U.S. patent application number 15/665973 was filed with the patent office on 2018-02-01 for apelin fusion proteins and uses thereof.
The applicant listed for this patent is Regeneron Pharmaceuticals, Inc.. Invention is credited to Andrew Murphy, Panayiotis Stevis.
Application Number | 20180030099 15/665973 |
Document ID | / |
Family ID | 50680161 |
Filed Date | 2018-02-01 |
United States Patent
Application |
20180030099 |
Kind Code |
A1 |
Stevis; Panayiotis ; et
al. |
February 1, 2018 |
Apelin Fusion Proteins and Uses Thereof
Abstract
The invention provides a fusion protein or polypeptide
comprising an apelin peptide fused to a multimerizing component.
The invention also provides a fusion protein or polypeptide
comprising an apelin peptide fused to an Fc domain, a fragment of
an Fc domain, or a variant of an Fc domain. Apelin Fc-fusion
polypeptides are capable of binding to the apelin receptor (APLNR).
Apelin Fc-fusion polypeptides are capable of activating the APLNR
and have improved pharmacokinetic properties compared to apelin
peptides that are not fused to an Fc or an Fc fragment. Apelin
Fc-fusion polypeptides are useful in diseases and conditions
related to cardiovascular function, diabetes, cancer, obesity and
other apelin-related conditions.
Inventors: |
Stevis; Panayiotis; (West
Orange, NJ) ; Murphy; Andrew; (Croton-on-Hudson,
NY) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Regeneron Pharmaceuticals, Inc. |
Tarrytown |
NY |
US |
|
|
Family ID: |
50680161 |
Appl. No.: |
15/665973 |
Filed: |
August 1, 2017 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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15146730 |
May 4, 2016 |
9751921 |
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15665973 |
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14212753 |
Mar 14, 2014 |
9353163 |
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15146730 |
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61786172 |
Mar 14, 2013 |
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61906567 |
Nov 20, 2013 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C07K 14/47 20130101;
A61P 35/00 20180101; A61P 3/04 20180101; A61K 38/00 20130101; A61P
9/12 20180101; A61P 35/04 20180101; A61P 9/00 20180101; A61P 3/10
20180101; A61P 31/18 20180101; A61P 3/12 20180101; A61P 9/10
20180101; A61P 9/04 20180101; C07K 2319/30 20130101; C07K 14/435
20130101 |
International
Class: |
C07K 14/47 20060101
C07K014/47; C07K 14/435 20060101 C07K014/435 |
Claims
1-48. (canceled)
49. A polypeptide comprising an apelin peptide fused to an Fc
domain, a fragment of an Fc domain, or variant of an Fc domain,
wherein the N-terminus of the apelin peptide is fused to the
C-terminus of the Fc domain or fragment or variant thereof,
optionally via a peptide linker, and wherein the apelin peptide is
selected from the group consisting of apelin61-77 (apelin-17),
apelin63-77 (apelin-15), apelin64-77 (apelin-14), apelin66-77
(apelin-12), apelin67-77 (apelin-11), apelin68-77 (apelin-10),
apelin73-77 (apelin-5), apelin61-76 (apelin-K16P), apelin61-75
(apelin-K15M), apelin61-74 (apelin-K14P), apelin65-77
(apelin-F13A), apelin65-76, apelin65-75, apelin66-76, apelin67-76,
apelin66-75, apelin67-75, and [Pyr.sup.1]Apelin-13.
50. The polypeptide of claim 49, wherein the apelin peptide is
selected from the group consisting of apelin65-77 (apelin-F13A),
apelin65-76, apelin65-75, apelin66-76, apelin67-76, apelin66-75,
apelin67-75, apelin66-77 (apelin-12), and apelin67-77
(apelin-11).
51. The polypeptide of claim 50, wherein the apelin peptide is
apelin65-75.
52. The polypeptide of claim 50, wherein the apelin peptide is
apelin66-77 (apelin-12).
53. The polypeptide of claim 50, wherein the apelin peptide is
apelin66-76.
54. The polypeptide of claim 50, wherein the apelin peptide is
apelin67-76.
55. The polypeptide of claim 50, wherein the apelin peptide is
apelin66-75.
56. The polypeptide of claim 49, wherein the apelin peptide is
fused to the Fc domain, or fragment thereof, via one or more
peptide linkers, optionally wherein the one or more peptide linkers
comprise one or more Gly-Ser linkers.
57. The polypeptide of claim 49, wherein the Fc domain is selected
from the group consisting of IgG1 CH2 domain and IgG1 CH3 domain;
IgG4 CH2 domain and IgG4 CH3 domain; IgG1 CH2 domain and IgG4 CH3
domain; and IgG4 CH2 domain and an IgG1 CH3 domain, optionally
wherein the Fc domain further comprises an IgG hinge domain or a
fragment or variant thereof.
58. The polypeptide of claim 57, wherein the Fc domain comprises an
IgG hinge domain comprising SEQ ID NO: 14, SEQ ID NO: 17, SEQ ID
NO: 18, SEQ ID NO:21, or SEQ ID NO: 22.
59. The polypeptide of claim 49, wherein the polypeptide (i) is an
APLNR agonist that exhibits an EC50 of less than about 10 nM, or
less than about 1 nM when measured in an in vitro APLNR activation
assay, and/or (ii) has an in vivo half-life of at least about 1
hour, or at least about 2, 3, 4, 5, 6, 7, 8, 9, or 10 hours.
60. A composition comprising the polypeptide of claim 49 and at
least one pharmaceutically acceptable carrier or diluent.
61. A nucleic acid molecule encoding the polypeptide of claim
49.
62. A vector comprising the nucleic acid molecule of claim 61.
63. A cell comprising the nucleic acid molecule of claim 61.
64. The cell of claim 63, wherein the nucleic acid is stably
integrated into the genome of the cell.
65. The cell of claim 63, wherein the cell is a eukaryotic cell,
optionally wherein the cell is selected from the group consisting
of CHO, COS, retinal cell, Vero, CV1, 293, MDCK, HaK, BHK, HeLa,
HepG2, WI38, MRC 5, Colo25, HB 8065, HL-60, Jurkat, Daudi, A431
(epidermal), CV-1, U937, 3T3, L cell, C127 cell, SP2/0, NS-0, MMT
cell, and tumor cell.
66. The cell of claim 63, wherein the cell is an animal cell,
optionally wherein the cell is a mammalian cell.
67. The cell of claim 66, wherein the cell is a CHO cell.
68. The cell of claim 67, wherein the cell is a CHO-K1 cell.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. application Ser.
No. 15/146,730, filed May 4, 2016, which is a continuation of U.S.
application Ser. No. 14/212,753, filed Mar. 14, 2014, which claims
the benefit under 35 USC .sctn.119(e) of U.S. Provisional Patent
Application No. 61/786,172, filed 14 Mar. 2013, and claims the
benefit under 35 USC .sctn.119(e) of U.S. Provisional Patent
Application No. 61/906,567, filed 20 Nov. 2013, which applications
are each specifically incorporated herein by reference in their
entirety.
SEQUENCE LISTING
[0002] This application incorporates by reference the Sequence
Listing submitted in Computer Readable Form as file
8050U503-Sequence.txt, created on Aug. 1, 2017 and containing
43,513 bytes.
FIELD OF THE INVENTION
[0003] The present invention relates to fusion proteins engineered
with multimerizing components, such as human immunoglobulin Fc
domains, fused to the N-terminus or C-terminus of apelin peptides.
Recombinant proteins of the invention and compositions thereof, are
useful in treating cardiovascular disease, ischemia-reperfusion,
diabetes, and other apelin-related therapies.
BACKGROUND OF THE INVENTION
[0004] Preproapelin is a 77 amino acid protein expressed in the
human CNS and peripheral tissues, e.g. lung, heart, and mammary
gland. Peptides comprising C-terminal fragments of varying size of
apelin peptide were shown to activate the G protein--coupled
receptor, APJ receptor (Habata, et al., 1999, Biochem Biophys Acta
1452:25-35; Hosoya, et al., 2000, JBC, 275(28):21061-67; Lee, et
al., 2000, J Neurochem 74:34-41; Medhurst, et al., 2003, J
Neurochem 84:1162-1172). Many studies indicate that apelin peptides
and analogues convey cardiovascular actions through their
interaction with the APJ receptor (also known as APLNR), such as
endothelium-dependent vasodilation (Tatemoto et al., 2001, Regul
Pept 99:87-92), positive inotropic actions (Szokodi et al., 2002,
Circ Res 91:434-440; Maguire, et al., 2009, Hypertension
54:598-604, epub before print on Jul. 13, 2009) and myocardial
regional ischemia and reperfusion (Pisarenko, et al., 2013, J
Pharmacol Pharmacother. "Effects of structural analogues of
apelin-12 in acute myocardial infarction in rats", epub before
print). Apelin-13, in particular, is a potent inotrope which could
provide a treatment for heart failure by increasing heart
contractility (Dai, et al., 2006, Eur J Pharmacol 553(1-3):
222-228; Maguire, et al, 2009, Hypertension. 54:598-604).
[0005] Transcriptional profiling of pre- and post-surgical
ventricle tissue in human patients revealed that APLNR was the most
significantly upregulated gene (Chen et al, 2003, Circulation,
108:1432-39). Apelin (apelin.sup.-/-) and APJ (APJ.sup.-/-)
knockout studies in mice suggest that lack of an endogenous
apelin-APJ pathway leads to a decreased ability to respond to
cardiovascular stress, such as exercise (Charo et al., 2009, Am J
Physiol. Heart Circ. Physiol., 297:H1904-1913).
[0006] Apelin has also been reported in the regulation of insulin
and mechanisms of diabetes and obesity-related disorders. In mouse
models of obesity, apelin is released from adipocytes and is
directly upregulated by insulin (Boucher, et al., 2005, Endocrinol
146:1764-71). Apelin knockout mice demonstrate diminished insulin
sensitivity (Yue, et al., 2010, Am J Physiol Endocrinol Metab
298:E59-E67).
[0007] APLNR-modulating agents also find utility in HIV treatment,
since synthetic apelin peptides inhibited HIV-1 entry into
CD4-APLNR-expressing cells (Cayabyab, M., et al., 2000, J. Virol.
74: 11972-11976). Furthermore, APLNR inhibitors, i.e. capable of
blocking pathological angiogenesis, may be useful in inhibiting
tumor growth or vascularization in the retina (Kojima, Y. and
Quertermous, T., 2008, Arterioscler Thromb Vasc Biol; 28;
1687-1688; Rayalam, S. et al. 2011, Recent Pat Anticancer Drug
Discov 6(3):367-72). Apelin neuroprotection is also seen where
apelin-13, apelin-17 and apelin-36 act through signaling pathways
to promote neuronal survival (Cheng, B, et al., 2012, Peptides
37(1):171-3).
[0008] APLNR binding agents are useful in ameliorating
cardiovascular disease, as well as cancer, and diabetes, among
other apelin related diseases. Since apelin peptides are rapidly
cleared from the circulation and have a short plasma half-life of
no more than eight minutes (Japp, et al, 2008, J of Amer College
Cardiolog, 52(11):908-13), apelin is currently dosed continuously
to see a therapeutic effect.
[0009] There is a need in the art for improved apelin binding
agents as therapeutic agents, particularly those having extended
half-life, while maintaining APLNR binding activity.
SUMMARY OF THE INVENTION
[0010] The present invention provides apelin fusion proteins, such
as apelin fused to an Fc domain, engineered to deliver biologically
active apelin peptides. In particular, apelin fusion proteins have
improved pharmacokinetic properties compared to wild-type apelin
peptides while maintaining APLNR activity.
[0011] One aspect of the invention provides a polypeptide
comprising an apelin peptide fused to a multimerizing component. In
one embodiment, the multimerizing component comprises an amino acid
sequence containing at least one cysteine residue. In another
embodiment, the multimerizing component comprises an amino acid
sequence containing a leucine zipper, a helix-loop motif, a
coiled-coil motif, or an immunoglobulin-derived domain. In another
embodiment, the multimerizing component comprises an amino acid
sequence containing an Fc domain.
[0012] In a related aspect, the invention provides a polypeptide
comprising an apelin peptide fused to an Fc domain, a fragment of
an Fc domain, or variant of an Fc domain. In some cases, the
polypeptide can be part of a higher order structure, such as a
protein or multimeric complex. In some embodiments, the apelin
peptide is fused to the Fc domain, or fragment thereof, via one or
more peptide linkers. In other embodiments, the apelin peptide is
fused to the C-terminus of said Fc domain, or the apelin peptide is
fused to the N-terminus of said Fc domain, or fragment thereof.
[0013] In one embodiment, the Fc domain of any of the apelin fusion
proteins described herein comprises an immunoglobulin CH2 domain or
an immunoglobulin CH3 domain. In another embodiment, the Fc domain
comprises an immunoglobulin CH2 and CH3 domain. In some
embodiments, the Fc domain is selected from the group consisting of
IgG1 CH2 and CH3 domain, IgG4 CH2 and CH3 domain, IgG1 CH2 and an
IgG4 CH3 domain, and IgG4 CH2 and an IgG1 CH3 domain. In other
embodiments, the Fc domain comprises an IgG hinge domain. In still
other embodiments, the Fc domain comprises an IgG hinge domain
selected from the group consisting of SEQ ID NO: 14, SEQ ID NO: 17,
SEQ ID NO: 18, SEQ ID NO: 21, and SEQ ID NO: 22.
[0014] In another embodiment, the polypeptide comprises a monomeric
fusion polypeptide capable of forming a dimer. In some embodiments,
the fusion polypeptide forms at least one disulfide bond with a
second polypeptide.
[0015] In another related aspect, the invention provides an apelin
receptor (APNLR) binding molecule comprising: an apelin peptide
component, a human IgG Fc domain, and at least one linker
component. In some embodiments, the apelin receptor (APNLR) binding
molecule is an APLNR agonist, and in other cases the apelin
receptor (APNLR) binding molecule is an APLNR antagonist.
[0016] In another aspect of the invention, an apelin fusion
polypeptide or an apelin receptor binding molecule is provided that
has a plasma or serum in vivo half-life of at least about 1 hour,
or at least about 2, 3, 4, 5, 6, 7, 8, 9, or 10 or more hours.
[0017] In some embodiments, the apelin fusion polypeptide or
receptor binding molecule of the invention comprises an apelin
peptide selected from the group consisting of apelin42-77
(apelin-36), apelin61-77 (apelin-17), apelin63-77 (apelin-15),
apelin64-77 (apelin-14), apelin65-77 (apelin-13), apelin66-77
(apelin-12), apelin67-77 (apelin-11), apelin68-77 (apelin-10),
apelin73-77 (apelin-5), apelin61-76 (apelin-K16P), apelin61-75
(apelin-K15M), apelin61-74 (apelin-K14P), apelin-F13A, apelin65-76,
apelin65-75, apelin66-76, apelin67-76, apelin66-75, apelin 67-75,
and [Pyr.sup.1]Apelin-13.
[0018] In certain aspects, the apelin fusion polypeptide or apelin
receptor binding molecule is a serum stable protein. In some
embodiments, the polypeptide has 95%, or 96%, or 97%, or 98%, or
99% or greater sequence identity to the amino acid sequence
comprising SEQ ID NO: 2 or SEQ ID NO: 4. In other aspects, the
polypeptide comprises an amino acid sequence at least 99% identical
to SEQ ID NO: 2 or SEQ ID NO: 4. In other aspects, the polypeptide
has an amino acid sequence comprising SEQ ID NO: 2 or SEQ ID NO: 4.
In still other aspects, the polypeptide has an amino acid sequence
selected from the group consisting of SEQ ID NO: 39, SEQ ID NO: 40
and SEQ ID NO: 41.
[0019] In certain aspects, the invention provides a recombinant
polypeptide, wherein the polypeptide comprises
N'-P1.sub.m-X1.sub.n-X2-X3-P2-A1-C', wherein: N' is the N-terminus
and C' is the C-terminus of the polypeptide; P1 is a peptide
linker; X1 comprises an IgG hinge domain; X2 comprises an IgG CH2
domain; X3 comprises an IgG CH3 domain, P2 is a peptide linker; and
A1 is an amino acid sequence comprising a human apelin peptide, or
a fragment or derivative thereof; wherein m=0 or 1, and n=0 or
1.
[0020] In certain aspects, the invention provides a recombinant
polypeptide, wherein the polypeptide comprises
N'-A1-P2-X1.sub.n-X2-X3-C', wherein: N' is the N-terminus and C' is
the C-terminus of the polypeptide; A1 is an amino acid sequence
comprising a human apelin peptide, or a fragment or derivative
thereof; P2 is a peptide linker; X1 comprises an IgG hinge domain;
X2 comprises an IgG CH2 domain; and X3 comprises an IgG CH3 domain;
wherein n=0 or 1.
[0021] In a second aspect, the invention provides a nucleic acid
molecule encoding any apelin fusion polypeptide or apelin receptor
binding molecule of the invention. In one embodiment, the nucleic
acid molecule has a sequence selected from the group consisting of
SEQ ID NO: 27 and SEQ ID NO: 28. In other embodiments, the nucleic
acid molecule encodes for an amino acid sequence selected from the
group consisting of SEQ ID NO: 2, SEQ ID NO: 4, SEQ ID NO: 39, SEQ
ID NO: 40 and SEQ ID NO: 41.
[0022] In a third aspect, the invention provides vectors and cells
comprising the nucleic acid molecules encoding an apelin fusion
polypeptide or an apelin receptor binding molecule of the
invention. In one embodiment, the vectors encode a nucleic acid
molecule linked to a signal peptide sequence.
[0023] The invention also provides vectors encoding apelin fusion
proteins comprising a nucleotide sequence encoding a signal
peptide. The invention further provides vectors encoding apelin
fusion proteins comprising a nucleotide sequence encoding a peptide
linker fused to the C-terminus of a signal peptide placed upstream
of the fusion protein.
[0024] In a fourth aspect, the invention provides a process for
determining APLNR activity of a test molecule, contacting cells
expressing APLNR, with the apelin fusion protein of the invention
under the same test conditions as the test molecule, to determine
whether the test molecule is an APLNR agonist or an APLNR
antagonist.
[0025] In one embodiment, the invention provides a process for
determining activation of an APLN receptor (APLNR) comprising: (a)
contacting cells expressing APLNR with a test molecule, under
conditions permitting the activation of the APLNR, (b) measuring
APLNR activity, (c) separately contacting cells expressing APLNR
with an apelin fusion protein of the invention under the same
conditions as in step (a), (d) measuring APLNR activity of the
cells in step (c) in the same manner as step (b), wherein the
measurement of APLNR activity in step (b) compared to the
measurement of APLNR activity in step (d) determines that the test
molecule activates the APLNR.
[0026] Another aspect of the invention provides a method of making
a fusion protein comprising apelin, said method comprising: (a)
transfecting a host cell with a nucleic acid molecule encoding the
fusion protein, wherein the nucleic acid molecule comprises a
nucleotide sequence encoding a signal peptide, fused to either i) a
nucleotide sequence encoding an Fc domain of human IgG linked to a
nucleotide sequence encoding an apelin peptide, at the N-terminus
of said apelin peptide, or ii) a nucleotide sequence encoding an
apelin peptide linked to a nucleotide sequence encoding an Fc
domain of a human IgG, at the N-terminus of said Fc domain, and (b)
making the fusion protein by expressing the nucleic acid molecule
of (a) in the host cell. The invention provides host cells
secreting the fusion proteins of the invention into the cell
culture medium.
[0027] In yet another aspect, the invention provides a method for
treatment of a disease or condition related to apelin in a subject
in need thereof, the method comprising administering to the subject
a therapeutically effective amount of the apelin fusion proteins of
the invention. The invention also provides a method for treating
the disease or condition selected from the group consisting of
cardiovascular disease, acute decompensated heart failure,
congestive heart failure, myocardial infarction, cardiomyopathy,
ischemia, ischemia/reperfusion injury, pulmonary hypertension,
diabetes, obesity, cancer, metastatic disease, fluid homeostasis,
pathological angiogenesis, retinopathy, fibrosis, and HIV
infection, the method comprising administering to the subject a
therapeutically effective amount of the apelin fusion protein of
the invention.
[0028] The invention further provides compositions and kits
comprising an apelin fusion polypeptide or an apelin receptor
binding molecule of the invention. In some embodiments, the kit
comprises one or more containers filled with at least one apelin
fusion protein or polypeptide of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0029] FIG. 1A depicts components of an hFc-Apelin fusion protein,
such as the amino acid sequence of SEQ ID NO: 2. The sequence of
SEQ ID NO: 2 consists of (from N-terminus to C-terminus) human IgG1
Fc (underlined), G4S repeat peptide linker (italicized), and
Apelin-13 (double-underlined).
[0030] FIG. 1B represents a secreted Fc-Apelin fusion protein and
its components in the form of a homodimer.
[0031] FIG. 2A depicts the components of an Apelin-hFc fusion
protein, such as the amino acid sequence of SEQ ID NO: 4. The
sequence of SEQ ID NO: 4 consists of (from N-terminus to
C-terminus) Apelin-13 (double-underlined), G4S repeat peptide
linker (italicized), and human IgG1 Fc (underlined).
[0032] FIG. 2B represents a secreted Apelin-Fc fusion protein and
its components in the form of a homodimer.
[0033] FIG. 3A illustrates the migration of Apelin Fc-fusion
proteins and protein ladder control on an SDS-PAGE gel. Lane
1=protein marker measurements (31 and 38 kD); Lane 2=hFc-apelin-13
(SEQ ID NO: 2); Lane 3=apelin13-hFc protein (SEQ ID NO: 4); Lane
4=hFc only.
[0034] FIG. 3B illustrates the reactivity of either 10 ng or 100 ng
of isolated hFc-apelin13 or apelin13-hFc protein in a Western blot
with anti-apelin antibody.
[0035] FIG. 4 represents the dose-response curve and half-maximal
concentrations (EC50s) of each of the following ligands: apelin-13
(- -), hFc-apelin13 (-.box-solid.-), or apelin13-hFc
(-.diamond-solid.-) in a CRE-luc assay by measuring
forskolin-induced cAMP response in APJ (APNLR)-expressing
cells.
[0036] FIG. 5 represents the dose-response curve and half-maximal
concentrations (EC50s) of each of the following ligands: apelin-13
(- -), hFc-apelin13 (-.box-solid.-), apelin13-hFc
(-.tangle-solidup.-), or hFc only (--) in a .beta.-arrestin
assay.
[0037] FIG. 6 represents the normalized p-ERK assay dose-response
curve and half-maximal concentrations (EC50s) of hFc-apelin13 (- -)
or apelin13-hFc (-.box-solid.-), compared to hFc
(-.tangle-solidup.-), showing activation of APNLR-expressing cells
by both ligands.
[0038] FIG. 7A shows the stability of 2.8 mg/kg apelin13-hFc
(-.box-solid.-) in serum of subcutaneously dosed C57/Bl6 mice,
reaching levels of about 10 .mu.g/mL for up to 48 hrs, compared to
levels of hFc alone (- -).
[0039] FIG. 7B shows stability of 5 mg/kg hFc-apelin13
(-.box-solid.-) in serum of subcutaneously dosed C57/Bl6 mice,
reaching 3 .mu.g/mL at 24 hrs, and gradually decreasing to 1
.mu.g/mL at about 14 days.
DETAILED DESCRIPTION OF THE INVENTION
[0040] It is to be understood that this invention is not limited to
particular methods, and experimental conditions described, as such
methods and conditions may vary. It is also to be understood that
the terminology used in this specification is for the purpose of
describing particular embodiments only, and is not intended to be
limiting, since the scope of the present invention is defined by
the claims.
[0041] As used in this specification and the appended claims, the
singular forms "a", "an", and "the" include plural references
unless the context clearly dictates otherwise. Thus for example, a
reference to "a method" includes one or more methods, and/or steps
of the type described herein and/or which will become apparent to
those persons skilled in the art upon reading this disclosure.
[0042] Unless defined otherwise, all technical and scientific terms
used in this application have the same meaning as commonly
understood by one of ordinary skill in the art to which this
invention belongs. Although any methods and materials similar or
equivalent to those described in this specification can be used in
the practice of the present invention, particular methods and
materials are now described. All publications mentioned herein are
incorporated herein by reference in their entirety.
Fusion Proteins
[0043] The term "immunoglobulin" (Ig) refers to a class of
structurally related glycoproteins consisting of two pairs of
polypeptide chains, one pair of light (L) chains and one pair of
heavy (H) chains, which may all four be inter-connected by
disulfide bonds. The structure of immunoglobulins has been well
characterized. See for instance Fundamental Immunology Ch. 7 (Paul,
W., ed., 2nd ed. Raven Press, N. Y. (1989)). Each heavy chain
typically comprises a heavy chain variable region (abbreviated
herein as V.sub.H or VH) and a heavy chain constant region (C.sub.H
or CH). The heavy chain constant region typically comprises three
domains, CH1, CH2, and CH3. The CH1 and CH2 domains are linked by a
hinge. The Fc portion comprises at least the CH2 and CH3
domains.
[0044] Typically, the numbering of amino acid residues of
immunoglobulins is according to IMGT, Sequences of Proteins of
Immunological Interest, 5th Ed. Public Health Service, National
Institutes of Health, Bethesda, Md. (1991), or by the EU numbering
system of Kabat (also known as "EU numbering" or "EU index"), e.g.,
as in Kabat, E. A. et al. Sequences of Proteins of Immunological
interest. 5.sup.th ed. US Department of Health and Human Services,
NIH publication No. 91-3242 (1991).
[0045] As used in the specification, a "multimerizing component" is
any macromolecule, protein, polypeptide, peptide, or amino acid
that has the ability to associate with a second multimerizing
component of the same or similar structure or constitution. For
example, a multimerizing component may be a polypeptide comprising
an immunoglobulin C.sub.H3 domain. A non-limiting example of a
multimerizing component is an Fc portion of an immunoglobulin,
e.g., an Fc domain of an IgG selected from the isotypes IgG1, IgG2,
IgG3, and IgG4, as well as any allotype within each isotype group.
In certain embodiments, the multimerizing component is an Fc
fragment or an amino acid sequence of 1 to about 500 amino acids in
length containing at least one cysteine residues. In other
embodiments, the multimerizing component is a cysteine residue, or
a short cysteine-containing peptide. Other multimerizing domains
include peptides or polypeptides comprising or consisting of a
leucine zipper, a helix-loop motif, or a coiled-coil motif.
[0046] The term "Fc" refers to a portion of a heavy chain constant
region that comprises at least the CH2 and CH3 domains that
typically bind to an Fc receptor e.g., an Fc.gamma.R, namely
Fc.gamma.RI (CD64), Fc.gamma.RII (CD32), Fc.gamma.RIII (CD16) or an
FcRn, i.e., a neonatal Fc receptor. If the CH2 and CH3 region
contains deletions, substitutions, and/or insertions or other
modifications that render it unable to bind any Fc receptor, then
the CH2 and CH3 region is considered to be non-functional in terms
of its typical biological function.
[0047] The phrase "fusion proteins", and specifically "apelin
fusion proteins", includes recombinant polypeptides and proteins
derived from apelin that have been engineered to contain a
multimerizing component as described herein.
[0048] The phrase "Fc-fusion proteins", and specifically
"apelin-Fc" or "Fc-apelin" fusion proteins, includes recombinant
polypeptides and proteins derived from apelin that have been
engineered to contain an Fc fragment as described herein. For
example, an "apelin Fc-fusion protein" includes a chimeric protein
comprising an amino acid sequence of an apelin peptide or analogue
fused to an amino acid sequence of an Fc domain of Ig, either at
the N-terminus or the C-terminus, with or without peptide linkers.
Examples of peptides used in fusion proteins are known in the art
(see e.g. Dumont, et al., 2006, Biodrugs 20(3):150-160). Fc-fusion
proteins are also referred to in the art as immunoadhesins.
[0049] The phrase "fused to", as used herein, means (but is not
limited to) a polypeptide formed by expression of a chimeric gene
made by combining more than one sequence, typically by cloning one
gene into an expression vector in frame with a second gene such
that the two genes are encoding one continuous polypeptide. In
addition to being made by recombinant technology, parts of a
polypeptide can be "fused to" each other by means of chemical
reaction, or other means known in the art for making custom
polypeptides.
[0050] The term "protein" is meant to include quaternary
structures, ternary structures and other complex macromolecules
composed of at least one polypeptide. The term "protein" includes
polypeptide.
[0051] As used herein, a "polypeptide" is a single linear polymer
chain of amino acids bonded together by peptide bonds between the
carboxyl and amino groups of adjacent amino acid residues. The term
"protein" may also be used to describe a large polypeptide, such as
a seven transmembrane spanning domain protein.
[0052] The polypeptides of the invention comprise amino acid
sequences that are derived from an immunoglobulin domain. A
polypeptide or amino acid sequence "derived from" a designated
protein or polypeptide refers to the origin of the polypeptide. As
used herein, "isotype" refers to the immunoglobulin class or
subclass (for instance, IgG1, IgG2, IgG3, IgG4, IgD, IgA, IgE, or
IgM) that is encoded by heavy chain constant region genes.
[0053] The phrase "heavy chain" or "immunoglobulin (Ig) heavy
chain", as used herein, includes Ig heavy chain constant region
sequence from any organism, and unless otherwise specified includes
a heavy chain variable domain. Heavy chain variable domains include
three heavy chain complementary determining regions (CDRs) and four
framework regions (FRs), unless otherwise specified. Fragments of
heavy chain variable domains include CDRs, or both CDRs and FRs. A
typical heavy chain constant region (CH) has, following the
variable domain, from N-terminal to C-terminal: a CH1 domain, a
hinge, a CH2 domain, and a CH3 domain. A functional fragment of a
heavy chain, e.g. in an antigen-binding protein, includes a
fragment that is capable of specifically recognizing an antigen
(e.g., recognizing the antigen with a K.sub.D in the micromolar,
nanomolar, or picomolar range), that is capable of being expressed
in and secreted from a cell, and that comprises at least one
CDR.
[0054] Flow cytometry-based autologous secretion trap (FASTR)
methods, which utilize a membrane-bound human Fc.gamma. receptor
(hFc.gamma.R) to capture co-secreted proteins, can be used to
rapidly isolate high expression clones expressing or secreting an
antibody or Fc-fusion protein. (See, US20090137416 A1, which is
herein incorporated by reference.) Such high expression clones may
be employed to isolate cells expressing proteins comprising an
Fc-fusion protein as described herein. FASTR methods may be
utilized to directly screen and isolate cells expressing any
recombinant polypeptide or Fc-fusion protein of the invention.
[0055] The term "hinge", as used herein, is intended to include the
region of consecutive amino acid residues that connect the
C-terminus of the CH1 to the N-terminus of the CH2 domain of an
immunoglobulin. Several amino acids of the N-terminus of the CH2
domain, which are coded by the CH2 exon, are also considered part
of the "lower hinge". Without being bound by any one theory, amino
acids of the hinge region of IgG1, IgG2 and IgG4 have been
characterized as comprising 12-15 consecutive amino acids encoded
by a distinct hinge exon, and several N-terminal amino acids of the
CH2 domain (encoded by the CH2 exon) (Brekke, O. H., et al., 1995,
Immunology Today 16(2):85-90). On the other hand, IgG3 comprises a
hinge region consisting of four segments: one upper segment
resembling the hinge region of IgG1, and 3 segments that are
identical amino acid repeats unique to IgG3.
[0056] Amino acid residues derived from Ig domains, such as human
IgG, are identified herein by the EU numbering system of Kabat,
also known as "EU numbering" or the "EU index" (according to Kabat,
E. A. et al. Sequences of Proteins of Immunological interest.
5.sup.th ed. US Department of Health and Human Services, NIH
publication No. 91-3242, 1991, and updated according to the
IMGT.RTM. Scientific Chart, IMGT.RTM., the international
ImMunoGeneTics information System.RTM.,
http://www.imgt.org/IMGTScientificChart/Numbering/Hu_IGHGnber.html,
created: 17 May 2001, last updated:10 Jan. 2013).
[0057] For example, EU numbering for human IgG1 hinge amino acids
and the corresponding IMGT unique numbering convention, and the
Kabat numbering convention (according to Kabat, E. A. et al, 1991,
and IMGT.RTM. Scientific Chart supra) are listed in Table 1.
TABLE-US-00001 TABLE 1 IgG1 hinge numbering IgG1 (IGHG1) IMGT
Unique amino acids Numbering for EU Kabat [SwissProt P01857] the
hinge Numbering Numbering (E) 1 216 226 P 2 217 227 K 3 218 228 S 4
219 232.sup.a [229].sup.b C 5 220 233.sup.a [230].sup.b D 6 221
234.sup.a [232].sup.b K 7 222 235 T 8 223 236 H 9 224 237 T 10 225
238 C 11 226 239 P 12 227 240 P 13 228 241 C 14 229 242 P 15 230
243 Amino acids resulting from exon splicing are shown in
parentheses. .sup.anumbering according to the last updated IMGT
Scientific Chart .sup.bnumbering according to EU index as
originally reported in Kabat, EA, et al. 1991 See also, e.g.,
Lefranc, M.-P. et al., Devel Comp Immunol, 29, 185-203 (2005); and
Edelman, G. M. et al. PNAS USA, 63: 78-85 (1969).
TABLE-US-00002 TABLE 2 IgG1 C-domain hinge numbering IgG1 (IGHG1)
IMGT Unique amino acids Numbering for EU Kabat [SwissProt P01857]
C-domains Numbering Numbering (A) 1.6 231 244 P 1.5 232 245 E 1.4
233 246 L 1.3 234 247 L 1.2 235 248 G 1.1 236 249
[0058] In one embodiment, Fc-fusion proteins of the invention
comprise an Fc domain or any Fc domain fragment or any Fc domain
variant. In some embodiments, the Fc domain comprises an Ig CH2 and
an Ig CH3 domain, or a fragment or variant thereof. In other
embodiments, the Fc domain comprises an Ig hinge domain, or a
fragment or variant thereof, an Ig CH2 domain or a fragment or
variant thereof and an Ig CH3 domain or a fragment or variant
thereof. In still other embodiments, the Fc domain comprises an Ig
CH1 domain or a fragment or variant thereof, an Ig hinge domain or
a fragment or variant thereof, an Ig CH2 domain a fragment or
variant thereof, and an Ig CH3 domain a fragment or variant
thereof.
[0059] The term "chimeric", as used herein, means composed of parts
of different origin. The phrase "chimeric protein", which
encompasses "chimeric polypeptides", includes a first amino acid
polypeptide linked to a second amino acid polypeptide that is not
normally linked in nature. The amino acid sequences may normally
exist as separate polypeptides or in a different arrangement on the
same polypeptide or protein, and are brought together in a fusion
polypeptide in a new arrangement.
[0060] The Fc domain may be chimeric, combining Fc sequences
derived from more than one immunoglobulin isotype. For example, a
chimeric Fc domain can comprise part or all of a CH2 sequence
derived from a human IgG1, human IgG2 or human IgG4 CH2 region, and
part or all of a CH3 sequence derived from a human IgG1, human IgG2
or human IgG4. A chimeric Fc domain can also contain a chimeric
hinge region. For example, a chimeric hinge may comprise an "upper
hinge" sequence, derived from a human IgG1, a human IgG2 or a human
IgG4 hinge region, combined with a "lower hinge" sequence, derived
from a human IgG1, a human IgG2 or a human IgG4 hinge region. A
chimeric Fc domain can have altered Fc receptor binding, which in
turn affects Fc effector function.
[0061] For certain therapies, the Fc domain may be engineered to
activate all, some, or none of the normal Fc effector functions,
without affecting the desired Fc-fusion protein's pharmacokinetic
properties. Therefore, engineered Fc domains that have altered Fc
receptor binding may have reduced side effects. Thus, in one
embodiment, the protein comprises a chimeric or otherwise modified
Fc domain. For an example of a chimeric Fc domain, see U.S.
Provisional Application No. 61/759,578, filed Feb. 1, 2013, which
is herein incorporated in its entirety.
[0062] The invention also provides apelin Fc-fusion proteins
comprising variant Fc domain sequences. Such "variant" Fc domains
and Fc domain fragments comprise one or more additions, deletions,
or substitutions of amino acids when compared to wild-type
sequence, but essentially function as desired, e.g. exhibit APLNR
activity and prolong half-life of the fusion protein, as described
in this specification.
[0063] In some embodiments, the Fc domain comprises an IgG CH2 and
CH3 domain. In other embodiments, the Fc domain comprises an IgG1
CH2 and CH3 domain, IgG4 CH2 and CH3 domain, IgG1 CH2 domain and an
IgG4 CH3 domain, or IgG4 CH2 domain and an IgG1 CH3 domain. In some
embodiments, the Fc domain is a chimeric Fc domain comprising a
fragment selected from the group consisting of CH1 domain, hinge
domain, CH2 domain and CH3 domain, wherein the fragment is derived
from IgG1, IgG2, IgG3, IgG4, IgD, IgA, IgE, or IgM. In some
embodiments, the chimeric Fc domain comprises a CH2 domain selected
from the group consisting of SEQ ID NO: 15, SEQ ID NO: 19, and SEQ
ID NO: 23. In some embodiments, the chimeric Fc domain comprises a
CH3 domain selected from the group consisting of SEQ ID NO: 16, SEQ
ID NO: 20, and SEQ ID NO: 24. In another embodiment, the Fc domain
comprises a chimeric IgG CH2-CH3 domain. Accordingly, variants and
fragments of such Fc domains are also part of this invention.
[0064] In one embodiment, the Fc domain comprises an IgG1, IgG2,
IgG3 or IgG4 hinge domain. In one embodiment, the hinge domain
comprises SEQ ID NO: 14, SEQ ID NO: 17, SEQ ID NO: 18, SEQ ID NO:
21 or SEQ ID NO: 22. In another embodiment, the Fc domain comprises
a chimeric hinge domain. In another embodiment, the Fc domain
comprises a chimeric hinge domain comprising a hinge fragment
selected from the group consisting of SEQ ID NO: 14, SEQ ID NO: 18,
and SEQ ID NO: 22.
[0065] According to certain embodiments of the present invention,
Fc-fusion proteins are provided comprising an Fc domain comprising
one or more mutations which enhance or diminish protein binding to
the FcRn receptor, e.g., at acidic pH as compared to neutral pH.
For example, the present invention includes Fc-fusion proteins
comprising a mutation in the CH2 or a CH3 region of the Fc domain,
wherein the mutation(s) increases the affinity of the Fc domain to
FcRn in an acidic environment (e.g., in an endosome where pH ranges
from about 5.5 to about 6.0). Such mutations may result in an
increase in serum half-life of the antibody when administered to an
animal. Non-limiting examples of such Fc modifications include,
e.g., a modification at position 250 (e.g., E or Q); 250 and 428
(e.g., L or F); 252 (e.g., L/Y/F/W or T), 254 (e.g., S or T), and
256 (e.g., S/R/Q/E/D or T); or a modification at position 428
and/or 433 (e.g., H/L/R/S/P/Q or K) and/or 434 (e.g., H/F or Y); or
a modification at position 250 and/or 428; or a modification at
position 307 or 308 (e.g., 308F, V308F), and 434. In one
embodiment, the modification comprises a 428L (e.g., M428L) and
434S (e.g., N434S) modification; a 428L, 2591 (e.g., V2591), and
308F (e.g., V308F) modification; a 433K (e.g., H433K) and a 434
(e.g., 434Y) modification; a 252, 254, and 256 (e.g., 252Y, 254T,
and 256E) modification; a 250Q and 428L modification (e.g., T250Q
and M428L); and a 307 and/or 308 modification (e.g., 308F or
308P).
[0066] For example, the present invention includes Fc-fusion
proteins comprising an Fc domain comprising one or more pairs or
groups of mutations selected from the group consisting of: 250Q and
248L (e.g., T250Q and M248L); 252Y, 254T and 256E (e.g., M252Y,
S254T and T256E); 428L and 434S (e.g., M428L and N434S); and 433K
and 434F (e.g., H433K and N434F). All possible combinations of the
foregoing Fc domain mutations, and other mutations within the
fusion proteins disclosed herein, are contemplated within the scope
of the present invention.
[0067] Modifications to the Fc domain of an Fc-fusion protein may
confer increased stability, such as resistance to degradation.
Fusion proteins may be modified using ordinary molecular biological
techniques and synthetic chemistry so as to improve their
resistance to proteolytic cleavage or resistance to metal
ion-related cleavage. Analogues of such polypeptides include
substitution variants made by the exchange of one amino acid for
another or substitution with residues other than naturally
occurring L-amino acids, e.g. D-amino acids or non-naturally
occurring synthetic amino acids.
[0068] In one embodiment, Fc-fusion proteins of the invention
comprise an apelin peptide fused to an Fc domain as described
herein.
[0069] In some embodiments, the Fc-fusion protein of the invention
activates the APLNR receptor and has a greater half-life than that
of an apelin peptide that is not fused to an Fc domain, such as a
greater half-life of more than eight minutes.
Apelin Ligand and Apelin Receptor
[0070] Apelin is produced endogenously as a prepropeptide of 77
amino acids which is cleaved to yield several shorter biologically
active fragments, or apelin peptides.
[0071] In some embodiments, Fc-fusion proteins of the invention
comprise an apelin peptide as described herein.
[0072] In some embodiments, the apelin peptide comprises a fragment
or derivative of the preproapelin polypeptide (SEQ ID NO: 5).
[0073] "Apelin peptides" includes specific apelin fragments and
derivatives known in the art, e.g., an apelin peptide comprising
amino acids 6-77, 40-77, 42-77, 43-77, 47-77, 59-77, 61-77, 63-77,
64-77, 65-77, 66-77, 67-77, 73-77, 1-25, 6-25, 42-64, 61-64, 61-74,
61-75, 61-76, 65-76, 65-75, 66-76, 67-76, 66-75, 67-75, 42-58,
42-57, 42-56, 42-55, 42-54, 42-53, or pyroglutamylated apelin65-77
([Pyr.sup.1]Apelin-13), of the preproapelin polypeptide (SEQ ID NO:
5). See e.g. U.S. Pat. No. 6,492,324, issued on Dec. 10, 2002, and
El Messari et al. 2004, J Neurochem, 90:1290-1301, which are both
herein incorporated by reference. In one embodiment, the apelin
peptide comprises amino acids 65-76, 65-75, 61-77, 63-77, 64-77,
65-77, 66-77, 67-77, 66-76, 67-76, 66-75, 67-75, or 42-77 of SEQ ID
NO: 5.
[0074] It has been demonstrated herein that fragments of apelin
peptides, for example peptides having C-terminal deletions, retain
their cellular activities (see also El Messari et al. 2004, J
Neurochem, 90:1290-1301). Certain apelin peptide derivatives, such
as apelin peptides and fusions having additional one or more
C-terminal amino acids, are shown herein to retain their cellular
activities. As such, fragments and derivatives of the apelin
peptides described in this specification are included in the
invention. Other fragments and derivatives of apelin peptides may
be made by recombinant technology by the skilled artisan.
[0075] In other embodiments, the apelin peptide is selected from
the group consisting of apelin40-77 (apelin-38), apelin42-77
(apelin-36), apelin43-77 (apelin-35), apelin47-77 (apelin-31),
apelin59-77 (apelin-19), apelin61-77 (apelin-17), apelin63-77
(apelin-15), apelin64-77 (apelin-14), apelin65-77 (apelin-13),
apelin66-77 (apelin-12, or A12), apelin67-77 (apelin-11),
apelin68-77 (apelin-10), apelin73-77 (apelin-5), apelin61-76
(apelin-K16P), apelin61-75 (apelin-K15M), apelin61-74
(apelin-K14P), and [Pyr.sup.1]Apelin-13.
[0076] In still other embodiments, the apelin peptide is selected
from the group consisting of apelin61-77 (apelin-17; SEQ ID NO: 7),
apelin65-77 (apelin-13; SEQ ID NO: 6), apelin-F13A (SEQ ID NO: 29),
apelin66-77 (apelin-12, or A12, SEQ ID NO: 32), apelin67-77
(apelin-11; SEQ ID NO: 33), apelin65-76 (SEQ ID NO:30), apelin65-75
SEQ ID NO: 31), apelin67-77 (SEQ ID NO: 6), apelin66-76 (SEQ ID NO:
34), apelin67-76 (SEQ ID NO: 35), apelin 66-75 (SEQ ID NO: 36),
apelin 67-75 (SEQ ID NO: 37), and [Pyr.sup.1]Apelin-13.
[0077] In some embodiments, the apelin peptide is modified to
minimize degradation and to enhance serum stability. In certain
embodiments, the modified apelin peptide is selected from the group
consisting of SEQ ID NO: 38 (apelin-13+5G), SEQ ID NO: 42
(apelin-13+R), SEQ ID NO: 43 (apelin-13+S), and SEQ ID NO: 44
(apelin-13+H).
[0078] In one embodiment, the apelin peptide is selected from the
group consisting of apelin-36 (SEQ ID NO: 8), apelin-17 (SEQ ID NO:
7), apelin-13 (SEQ ID NO: 6) and [Pyr.sup.1]Apelin-13. In another
embodiment, the apelin peptide comprises apelin-13 (SEQ ID NO: 6),
or a fragment thereof.
[0079] Apelin peptides are rapidly cleared from the circulation and
have a short plasma half-life of no more than eight minutes (Japp,
et al, 2008, J of Amer College Cardiolog, 52(11):908-13). Apelin
fusion proteins of the invention have increased half-life compared
to apelin peptides.
[0080] Included in the invention are analogues of apelin modified
to include non-standard amino acids or modified amino acids. Such
peptides containing non-natural, or natural but non-coded, amino
acids may be synthesized by an artificially modified genetic code
in which one or mode codons is assigned to encode an amino acid
which is not one of the standard amino acids. For example, the
genetic code encodes 20 standard amino acids, however, three
additional proteinogenic amino acids occur in nature under
particular circumstances: selenocysteine, pyrrolysine and
N-Formyl-methionine (Ambrogelly, et al. 2007, Nature Chemical
Biology, 3:29-35; Bock, A. et al, 1991, TIBS, 16 (12): 463-467; and
Theobald-Dietrich, A., et al., 2005, Biochimie, 87(9-10):813-817).
Post-translationally modified amino acids, such as carboxyglutamic
acid (.gamma.-carboxyglutamate), hydroxyproline, and hypusine, are
also included. Other non-standard amino acids include, but are not
limited to, citrulline, 4-benzoylphenylalanine, aminobenzoic acid,
aminohexanoic acid, N.sup..alpha.-methylarginine,
.alpha.-Amino-n-butyric acid, norvaline, norleucine,
alloisoleucine, t-leucine, .alpha.-Amino-n-heptanoic acid,
pipecolic acid, .alpha.,.beta.-diaminopropionic acid,
.alpha.,.gamma.-diaminobutyric acid, ornithine, allothreonine,
homoalanine, homoarginine, homoasparagine, homoaspartic acid,
homocysteine, homoglutamic acid, homoglutamine, homoisoleucine,
homoleucine, homomethionine, homophenylalanine, homoserine,
homotyrosine, homovaline, isonipecotic acid, .beta.-Alanine,
.beta.-Amino-n-butyric acid, .beta.-Aminoisobutyric acid,
.gamma.-Aminobutyric acid, .alpha.-aminoisobutyric acid, isovaline,
sarcosine, naphthylalanine, nipecotic acid, N-ethyl glycine,
N-propyl glycine, N-isopropyl glycine, N-methyl alanine, N-ethyl
alanine, N-methyl .beta.-alanine, N-ethyl .beta.-alanine,
octahydroindole-2-carboxylic acid, penicillamine, pyroglutamic
acid, sarcosine, t-butylglycine,
tetrahydro-isoquinoline-3-carboxylic acid, isoserine, and
.alpha.-hydroxy-.gamma.-aminobutyric acid. A variety of formats to
expand the genetic code are known in the art and may be employed in
the practice of the invention. (See e.g. Wolfson, W., 2006, Chem
Biol, 13(10): 1011-12.)
[0081] Apelin analogues incorporating such non-standard amino acids
or post-translational modifications can be synthesized by known
methods. Exemplary apelin analogues include
N.sup..alpha.-methylarginine-apelin-A12 analogue, [Nle.sup.75,
Tyr]apelin-36, [Glp.sup.65Nle.sup.75,Tyr.sup.77]apelin-13,
(Pyr.sup.1)[Met(O)11]-apelin-13, (Pyr.sup.1)-apelin-13,
[d-Ala.sup.12]-A12, and N-alpha-acetyl-nona-D-arginine amide
acetate.
[0082] Also included in the invention are analogues of the apelin
component of an apelin fusion protein modified to be resistant to
cleavage, for example cleavage by angiotensin converting enzyme 2
(ACE2). Such apelin analogues have been shown to have a marked
increase in efficacy compared to unmodified apelin ligands in in
vivo models of myocardial response to ischemia (Wang, et al. Jul.
1, 2013, J Am Heart Assoc. 2: e000249).
[0083] Such cleavage-protected apelin fusion proteins comprise
apelin peptides that are modified to include substitution variants,
i.e. variants made by the exchange of one amino acid for another at
one or more cleavage sites within the protein. Such amino acid
substitutions are envisioned to confer increased stability without
the loss of other functions or properties of the protein. Other
cleavage-protected apelin fusion proteins comprise apelin peptides
modified to include terminal amide or acetyl groups. In some
embodiments, cleavage-protected apelin fusion proteins comprise
proteinogenic amino acids, non-standard amino acids or
post-translationally modified amino acids. Still other
cleavage-protected or cleavage-resistant apelin fusion proteins
comprise modified apelin peptides that include one or more
additional N-terminal amino acids. It is desirable that such
modified apelin peptides do not alter the peptide's ability to
activate the APLNR. Exemplary modified apelin peptides and fusion
proteins of the invention that activate APLNR include SEQ ID NO:
38, SEQ ID NO: 39, SEQ ID NO: 40, SEQ ID NO: 41, SEQ ID NO: 42, SEQ
ID NO: 43, and SEQ ID NO: 44.
[0084] Apelin, as mentioned above, is known to be a ligand of
APLNR, a G protein-coupled receptor. The term "ligand", as used
herein, means a molecule that binds to another molecule such as a
receptor. A ligand molecule capable of binding to a G
protein-coupled receptor (GPCR) is selected from the group
consisting of an ion, small organic molecule, peptide, polypeptide,
antibody, bispecific antibody, antibody fragment, protein, and
large organic molecule. A ligand may be further characterized as,
for example, an agonist, partial agonist, inverse agonist,
antagonist, competitive antagonist, positive allosteric modulator
or negative allosteric modulator depending on the state of activity
it confers through the receptor to which it binds. For example, for
agonists to bind to a GPCR, other molecular interactions that keep
such GPCR in an inactive state are disrupted.
[0085] The term "agonist", as used herein, includes a moiety that
interacts with (directly or indirectly binds) and activates a
receptor, such as the APLNR receptor, and initiates a physiological
or pharmacological response characteristic of that receptor, such
as when bound to its endogenous ligand. For example, upon binding
to a GPCR, moieties may activate an intracellular response, enhance
GTP binding to cell membranes, or internalize the receptor. Such
agonist moiety can be for example a protein, polypeptide, peptide,
antibody, antibody fragment, large molecule, or small molecule.
[0086] The term "antagonist", as used herein, is intended to mean a
moiety that competitively binds to the receptor at the same site as
an agonist (for example, the endogenous ligand), but which does not
activate the intracellular response initiated by the active form of
the receptor, and thereby inhibits the intracellular response by an
agonist or partial agonist. In some cases, antagonists do not
diminish the baseline intracellular response in the absence of an
agonist or partial agonist. An antagonist does not necessarily have
to function as a competitive binding inhibitor, but may work by
sequestering an agonist, or indirectly modulating a downstream
effect.
[0087] G protein-coupled receptors (GPCRs), which are seven
transmembrane domain receptors, typically transduce their cellular
signals via heterotrimeric guanine nucleotide-binding proteins (G
proteins), consisting of an alpha (.alpha.), beta (.beta.), and
gamma (.gamma.) subunit, whereas the a subunit contains a binding
site for GTP/GDP, and the .beta..gamma. dimer is bound to the a
subunit in an inactive state. G proteins are naturally occurring on
the cytoplasmic side of the plasma membrane. Binding of an
extracellular ligand leads to a conformational change in the
receptor protein that allows it to make contact with a
guanine-nucleotide binding protein (G protein), and thus enhance
the exchange of GTP for GDP. Upon the exchange, the .beta..gamma.
dimer dissociates from the a subunit. Both the activated a subunit
and the .beta..gamma. dimer can influence intracellular effector
proteins.
[0088] In general, GPCRs activate a particular G.alpha. protein
subunit family, which leads to the activation or inactivation of a
particular signal transduction pathway. The apelin receptor (APLNR)
is a GPCR.
[0089] Upon interaction with a ligand or binding molecule, the
apelin receptor (APLNR) triggers one or more of several
intracellular signaling cascades including signaling initiated by:
1) inhibitory G protein subunit, g.alpha..sub.l/o, 2) activation of
ERKs through PKC, or 3) internalization of the GPCR. In other
words, the pharmacological and/or physiological response of APLNR
in its active state is determined by the downstream action of
G.alpha..sub.i subunits (which, e.g., inhibit adenylyl cyclase),
phosphorylated ERKs or internalized APLNR. It is understood that
other intracellular effectors may be engaged by an activated
APLNR.
[0090] Apelin receptor (APLNR) originally named APJ receptor
(O'Dowd, et al., 1993, Gene 136(1-2):355-360), was isolated from
human genomic DNA as a 380 amino acid 7-transmembrane domain orphan
receptor. (See NCBI RefSeq No. NP_005152, which is herein
incorporated by reference.) Apelin was shown to be the endogenous
ligand for APLNR (APJ) when tissue extracts from bovine stomach
revealed apelin peptides that stimulated acidification rate in CHO
cells expressing APLNR (APJ) in a range from 0.1-100 nM (Tatemoto,
et al., 1998, Biochem Biophys Res Comm 251:471-476).
[0091] The interaction between apelin and APLNR, and hence the
interaction between apelin fusion proteins and APLNR, can be
measured by a number of in vitro (e.g. as in a test tube or plate),
ex vivo (e.g. as in a cell culture from a living animal) and in
vivo (e.g. as in a living animal) bioassays known to the skilled
person in the relevant art.
[0092] In some embodiments, APLNR agonists are selected from the
group consisting of apelin-36, apelin-19, apelin-17, apelin-13,
apelin-12, N.sup..alpha.-methylarginine-apelin-A12 analogue,
[Nle.sup.75, Tyr]apelin-36, [Glp.sup.65Nle.sup.75,
Tyr.sup.77]apelin-13, (Pyr.sup.1)[Met(O)11]-apelin-13, and
(Pyr.sup.1)-apelin-13.
[0093] In one embodiment, the apelin fusion polypeptide is an APLNR
agonist selected from the group consisting of SEQ ID NO: 2, SEQ ID
NO: 4, SEQ ID NO: 39, SEQ ID NO: 40 and SEQ ID NO: 41, and
fragments or derivatives thereof.
[0094] Antagonists of the receptor are known to block the
hypotensive action of the APLNR. The apelin peptide derivative made
by modifying apelin-13 at its C-terminal phenylalanine (F) to
alanine (A) (apelin-13(F13A); SEQ ID NO: 29) was described by Lee,
et al. 2005 (Endocrinol 146(1):231-236) as a functional antagonist.
The APLNR antagonist F13A was also reported to improve circulatory
and renal function in cirrhotic animals, indicating that the
antagonist may have mediated the overactive effects of an
upregulated apelin system in pathogenic disease such as fibrosis of
the liver (Principe, A., et al. 2008, Hepatology, 48(4):1193-1201).
In some embodiments, APLNR antagonists are selected from the group
consisting of apelin-13(F13A) (SEQ ID NO: 29), [d-Ala.sup.12]-A12,
cyclo(1-6)CRPRLC-KH-cyclo(9-14)CRPRLC, and
N-alpha-acetyl-nona-D-arginine amide acetate (ALX40-4C; CAS
Registry No. 153127-49-2).
[0095] In another embodiment, the apelin fusion protein or
polypeptide comprises an APLNR binding molecule. In other
embodiments, the apelin fusion protein or polypeptide comprises an
APLNR agonist. In some embodiments, the fusion polypeptide of the
invention comprises an APLNR antagonist.
Receptor Assays
[0096] It is understood that receptor screening assays are employed
not only to the subject apelin fusion proteins of the invention,
but also any test compounds including agonists and antagonists of
the APLNR. Many receptor screening assays to determine activation
or inactivation of the APLNR are well-known in the art, and the
following examples are not intended to limit the scope of what the
inventors regard as their invention.
[0097] GPCR-mediated guanine nucleotide exchange is monitored by
measuring [.sup.35S]GTP.gamma.S binding to plasma membranes
prepared from cells expressing GPCRs of interest. The
[.sup.35S]GTP.gamma.S assay is generally useful for Gi/o-coupled
receptors because Gi/o is the most abundant G protein in most cells
and has a faster GDP-GTP exchange rate than other G proteins
(Milligan G., 2003, Trends Pharmacol Sci, 2003, 24:87-90).
Commercially available Scintillation Proximity Assay (SPA.TM.) kits
allow measurement of desired [.sup.35S]GTP.gamma.S-bound a subunit
(PerkinElmer, Waltham, Mass., USA).
[0098] Activation of Gi/o-coupled receptors results in decreased
adenylyl cyclase activity and therefore inhibition of cAMP in the
cell, via the G alpha subunits Gi or Go. To maximize the inhibition
signal, forskolin (a direct activator of adenylate cyclase) is
typically utilized to stimulate adenylyl cyclase in the assay, and
thus cAMP, thereby rendering the inhibition signal more easily
detectable. Radiometric GE Healthcare SPA.TM. (Piscataway, N.J.,
USA) and Perkin Elmer Flash-Plate.TM. cAMP assays are available, as
well as fluorescence or luminescence-based homogenous assays (e.g.
PerkinElmer AlphaScreen.TM., DiscoveRx HitHunter.TM. (Fremont,
Calif., USA), and Molecular Devices FLIPR.RTM. (Sunnyvale, Calif.,
USA)) to measure accumulation of intracellular cAMP.
[0099] The action of GPCRs that modulate cAMP levels, like APLNR,
may be linked to luciferase transcription in a cell by a cAMP
response element (CRE). A CRE-luc construct (CRE-responsive
luciferase) encodes a luciferase reporter gene under the control of
a promoter and tandem repeats of the CRE transcriptional response
element (TRE). Following activation of the receptor, cAMP
accumulation in the cell is measured by the amount of luciferase
expressed in the cell following addition of chemiluminescent
detection reagents. For APLNR, and other Gi-coupled receptors,
forskolin is added to induce cAMP and a decrease in CRE activity
(chemiluminescence) indicates GPCR activation. Various commercial
kits are available, such as from Promega (Madison, Wis., USA),
SABiosciences (A Qiagen Company, Valencia, Calif., USA), etc.
[0100] In some instances, agonist binding to the receptor may
initiate arrestin-mediated signaling, without triggering G
protein-mediated signaling or slow down G protein-mediated
signaling. Beta-arrestin (.beta.-arrestin) interaction with GPCRs
at the cell-surface can uncouple heterotrimeric G proteins to the
receptor and lead to other cell signaling cascades. .beta.-arrestin
is known to trigger endocytosis and activation of the ERK pathway.
In one example assay, bioluminescence resonance energy transfer or
BRET has been used to study the interaction of GPCRs fused to
Renilla luciferase (Rlu) with .beta.-arrestin fused to green
fluorescent protein (GFP). In this example, BRET is based on the
transfer of energy between recombinant expressed GPCR-Rlu and
.beta.-arrestin-GFP when they are in close proximity after the
addition of the luciferase substrate coelentcrazine, thus allowing
measurement of real-time evaluation of these protein-protein
interactions in whole cells.
[0101] Other assays have been developed, such as PathHunter.RTM.
GPCR assays (DiscoveRx Corp., Fremont, Calif., USA) that directly
measure GPCR activity by detecting .beta.-arrestin interaction with
the activated GPCR. Briefly, the GPCR is fused in frame with the
small enzyme fragment ProLink.TM. and co-expressed in cells stably
expressing a fusion protein of .beta.-arrestin and a deletion
mutant of .beta.-galactosidase (i.e. .beta.-gal, an enzyme
acceptor, or EA). Activation of the GPCR stimulates binding of
.beta.-arrestin to the ProLink-tagged GPCR and the complementation
of the two enzyme fragments results in formation of an active
.beta.-gal enzyme. An increase in enzyme activity (i.e. GPCR
activation) can be measured using chemiluminescent detection
reagents.
[0102] .beta.-arrestin molecules have been shown to regulate GPCR
internalization (i.e. endocytosis) following activation of GPCRs,
such as APLNR. Agonist-activation of GPCRs leads to conformational
changes, phosphorylation of the receptor, and activation of
.beta.-arrestin, or other pathways, to mediate receptor
sequestration from the cell surface. The sequestration mechanism
may be a means of desensitization (i.e. receptor is degraded
following internalization) or resensitization (i.e. receptor is
recycled back to the cell surface). See, e.g., Claing, A., et al.
2002, Progress in Neurobiology 66: 61-79, for review.
[0103] APLNR antagonists may block internalization of the receptor.
APLNR agonists may induce internalization and/or resensitization of
the APLNR (Lee, D K, et al. 2010, BBRC, 395:185-189). In some
embodiments, the APLNR agonist exhibits or induces increased APLNR
resensitization, as measured by an internalization assay. In other
embodiments, the APLNR agonist exhibits or induces increased
cell-surface receptor copy of the APLNR, as measured in an
internalization assay. Measuring the extent (such as an increase)
of receptor internalization in any internalization assay is done by
determining the difference between the noninternalized measurement
(i.e., cells without prior exposure to agonist) and the measurement
obtained with agonist in the assay.
[0104] Apelin receptor sequestration, and thus apelin receptor
copy, may be measured by a number of methods well-known in the art.
APLNR agonist stimulation may result in increased or decreased
receptor copy on the surface of a particular cell. For example, an
apelin receptor agonist that induces APLNR internalization may have
an effect on blood pressure. Receptor internalization assays are
routinely done employing, for example, fluorescently-labeled or
radiolabeled ligands, or immunofluorescent labels
(fluorescently-tagged anti-receptor antibodies), followed by
microscopy and digital imaging techniques (see, e.g., El Messari et
al. 2004, J Neurochem, 90:1290-1301; and Evans, N., 2004, Methods
of Measuring Internalization of G Protein--Coupled Receptors.
Current Protocols in Pharmacology. 24: 12.6.1-12.6.22).
[0105] Phosphorylated ERK (p-ERK) may be measured in cell lysates
from cells expressing APLNR receptors to determine APLNR
activation. Endogenous extracellular signal-regulated kinase 1 and
2 (ERK1 and ERK2), belong to a conserved family of serine/threonine
protein kinases and are involved cellular signaling events
associated with a range of stimuli. The kinase activity of ERK
proteins is regulated by dual phosphorylation at Threonine
202/Tyrosine 204 in ERK1, and Threonine 185/Tyrosine 187 in ERK2.
MEK1 and MEK2 are the primary upstream kinases responsible for ERK
1/2 in this pathway. Many downstream targets of ERK 1/2 have been
identified, including other kinases, and transcription factors. In
one example, the p-ERK 1/2 assay utilizes an enzyme-linked
immunosorbent assay (ELISA) method to measure specific
phosphorylation of ERK 1 in cellular lysates of cell cultures
expressing recombinant or endogenous receptors. In another example,
the p-ERK 1/2 assay uses a primary (non-conjugated) antibody which
recognizes phosphorylated Thr202/Tyr204 in ERK1 or
phos-Thr185/Tyr187 in ERK2 and a secondary conjugated antibody that
recognizes the primary antibody, whereas the secondary conjugated
mAb provides a method of detection such as a conjugate reacts with
an exogenously added substrate. Various commercial kits are
available, such as AlphaScreen.RTM. SureFire.TM. (PerkinElmer),
ThermoScientific (Waltham, Mass., USA), Sigma Aldrich (St. Louis,
Mo., USA), ELISAOne (TGR BioSciences (South Australia, Australia)
etc.).
[0106] As used herein, the term "binding", such as in the context
of the binding of ligand to a receptor (e.g. GPCR), or such as an
antibody binding to an antigen, typically refers to an interaction
or association between a minimum of two entities, or molecular
structures, such as a receptor-ligand interaction, or an
antibody-antigen interaction. Thus a "receptor binding molecule"
refers to a ligand or other moiety, such as a protein, that binds
to, i.e. interacts with, a receptor.
[0107] For instance, binding affinity between the ligand (e.g., an
apelin fusion protein) and the receptor (e.g., an APLNR or ligand
binding fragment of APLNR) typically corresponds to a K.sub.D value
of about 10.sup.-7 M or less, such as about 10.sup.-8 M or less,
such as about 10.sup.-9 M or less. Binding affinity can be
determined by any one or more of several methods, such as by
surface plasmon resonance (SPR) using a BIAcore 3000 instrument.
Accordingly, the ligand binds to the receptor with an affinity
corresponding to a K.sub.D value that is at least ten-fold lower,
such as at least 100 fold lower, for instance at least 1,000 fold
lower, such as at least 10,000 fold lower, for instance at least
100,000 fold lower than its affinity for binding to a non-specific
ligand (e.g., BSA, casein).
[0108] The term "K.sub.D" (M), as used herein, refers to the
dissociation equilibrium constant of a particular ligand-receptor
interaction. There is an inverse relationship between K.sub.D and
binding affinity, therefore the smaller the K.sub.D value, the
higher the affinity. Thus, the term "lower affinity" relates to a
lower ability to form an interaction and therefore a larger K.sub.D
value.
[0109] The term "k.sub.d" (sec.sup.-1 or 1/s), as used herein,
refers to the dissociation rate constant of a particular
ligand-receptor interaction. Said value is also referred to as the
k.sub.off value.
[0110] The term "k.sub.a" (M.sup.-1.times.sec.sup.-1 or 1/M), as
used herein, refers to the association rate constant of a
particular ligand-receptor interaction.
[0111] The term "K.sub.A" (M.sup.-1 or 1/M), as used herein, refers
to the association equilibrium constant of a particular
ligand-receptor interaction, or the association equilibrium
constant of antibody-antigen interaction. The association
equilibrium constant is obtained by dividing the k.sub.a by the
k.sub.d.
[0112] The term "EC.sub.50" or "EC50", as used herein, refers to
the half maximal effective concentration, which includes the
concentration of a ligand that induces a response, for example a
cellular response, halfway between the baseline and maximum after a
specified exposure time. The EC.sub.50 essentially represents the
concentration of a ligand where 50% of its maximal effect is
observed. Thus, with regard to cellular signaling, increased
activity is observed with a decreased EC.sub.50 value, i.e. half
maximal effective concentration value (less ligand needed to effect
a greater response).
[0113] In one embodiment, decreased binding refers to an increased
EC.sub.50 protein concentration, which enables half-maximal binding
to the target receptor or receptor-expressing cells.
[0114] In some embodiments, decreased activity refers to an
increased EC.sub.50 protein concentration, which enables
half-maximal cellular activation of the target receptor or
receptor-expressing cells.
[0115] The term "IC.sub.50" or "IC50", as used herein, refers to
the half maximal inhibitory concentration of a cellular response.
In other words, the measure of the effectiveness of a particular
moiety (e.g. protein, compound, or molecule) in inhibiting
biological or biochemical function, wherein an assay quantitates
the amount of such moiety needed to inhibit a given biological
process. Thus, with regard to cellular signaling, a greater
inhibitory activity is observed with a decreased IC.sub.50, or
half-maximal inhibitory concentration, value.
[0116] In one embodiment, the apelin fusion protein is an agonist
of the APLNR with an EC50 of less than about 100 nM, or less than
about 50 nM, or less than about 25 nM, or less than about 10 nM, or
less than about 1 nM, in an in vitro assay that measures activation
of the APLNR. In one embodiment, the apelin fusion protein
comprises an Fc domain linked to the N-terminus of an apelin
peptide, and exhibits an EC50 of less than about 1 nM, or less than
about 500 .mu.M.
Apelin Fusion Proteins of the Invention
[0117] Methods of making fusion proteins are known in the art. In
one such method, a DNA expression vector is engineered to contain
an apelin-encoding nucleic acid sequence linked in-frame to an
Fc-encoding nucleic acid sequence such that the DNA expression
vector expresses one contiguous fusion polypeptide. Apelin peptide
may be linked to the C-terminus or to the N-terminus of the
Fc-containing polypeptide. Apelin fusion proteins of the invention
are expected to be more stable than apelin peptides alone. Serum
stable proteins include proteins that confer resistance to
degradation or have a reduced clearance from the circulation.
Exemplary serum stable apelin fusion proteins of the invention
include SEQ ID NO: 2, SEQ ID NO: 4, SEQ ID NO: 39, SEQ ID NO: 40
and SEQ ID NO: 41.
[0118] In the context of constructing fusion proteins, the phrase
"joined in-frame" means that the components are linked together is
such a way that their complete translation, use or operation is
possible and thus not disrupted. For example, a fusion protein
comprising at least two polypeptides, may or may not have a linker
or spacer sequence between the polypeptides, and thus the
polypeptides are joined in-frame as one continuous polypeptide with
each polypeptide maintaining its operability. Two or more
polypeptides linked or fused together in a fusion protein are
typically derived from two or more independent sources, and
therefore a fusion protein comprises two or more linked
polypeptides not normally found linked in nature. Furthermore, DNA
encoding such fusion proteins may contain linker sequences that
maintain operable in-frame (e.g. triplet codon) translation of the
transcribed mRNA molecules encoding such polypeptides.
[0119] The phrase "operably linked", such as in the context of DNA
expression vector constructs, a control sequence, e.g., a promoter
or operator, is appropriately placed at a position relative to a
coding sequence such that the control sequence directs the
production of a polypeptide encoded by the coding sequence.
[0120] The term "signal peptide" or "signal peptide sequence" is
defined herein as a peptide sequence usually present at the
N-terminal end of newly synthesized secretory or membrane
polypeptides which directs the polypeptide across or into a cell
membrane of the cell (the plasma membrane in prokaryotes and the
endoplasmic reticulum membrane in eukaryotes). It is usually
subsequently removed by enzyme cleavage. In some embodiments, said
signal peptide may be capable of directing the polypeptide into a
cell's secretory pathway. In some embodiments, the signal peptide
comprises the amino acid sequence from 1-29 of mouse ROR1, GenBank
Accession No. BAA75480 (SEQ ID NO: 10). In other embodiments the
signal peptide has at least about 96%, or at least about 97%, or at
least about 98%, or at least about 99% homology to the signal
peptide amino acid sequence shown in SEQ ID NO: 9. In still other
embodiments, the signal peptide is encoded by a nucleotide having
at least about 96%, or at least about 97%, or at least about 98%,
or at least about 99% homology to the signal peptide nucleic acid
sequence shown in SEQ ID NO: 9.
[0121] In some embodiments, the components or peptides of an
Fc-fusion protein are separated by a linker (or "spacer") peptide.
Such peptide linkers are well known in the art (e.g., polyglycine)
and typically allow for proper folding of one or both of the
components of the fusion protein. The linker provides a flexible
junction region of the component of the fusion protein, allowing
the two ends of the molecule to move independently, and may play an
important role in retaining each of the two moieties' appropriate
functions. Therefore, the junction region acts in some cases as
both a linker, which combines the two parts together, and as a
spacer, which allows each of the two parts to form its own
biological structure and not interfere with the other part.
Furthermore, the junction region should create an epitope that will
not be recognized by the subject's immune system as foreign, in
other words, will not be considered immunogenic. Linker selection
may also have an effect on binding activity of the fusion molecule.
(See Huston, et al, 1988, PNAS, 85:16:5879-83; Robinson &
Bates, 1998, PNAS 95(11):5929-34; Arai, et al. 2001, PEDS,
14(8):529-32; and Chen, X. et al., 2013, Advanced Drug Delivery
Reviews 65:1357-1369.) In one embodiment, the apelin peptide is
connected to the C-terminus or to the N-terminus of the
Fc-containing polypeptide, or fragment thereof, via one or more
peptide linkers.
[0122] The length of the linker chain may be 2, 3, 4, 5, 6, 7, 8,
9, 10, 11, 12, 13, 14 15 or more amino acid residues, but typically
is between 5 and 25 residues. Examples of linkers include
polyGlycine linkers, such as Gly-Gly, Gly-Gly-Gly (3Gly), 4Gly,
5Gly, 6Gly, 7Gly, 8Gly or 9Gly. Examples of linkers also include
Gly-Ser peptide linkers such as Ser-Gly, Gly-Ser, Gly-Gly-Ser,
Ser-Gly-Gly, Gly-Gly-Gly-Ser, Ser-Gly-Gly-Gly, Gly-Gly-Gly-Gly-Ser,
Ser-Gly-Gly-Gly-Gly, Gly-Gly-Gly-Gly-Gly-Ser,
Ser-Gly-Gly-Gly-Gly-Gly, Gly-Gly-Gly-Gly-Gly-Gly-Ser,
Ser-Gly-Gly-Gly-Gly-Gly-Gly, (Gly-Gly-Gly-Gly-Ser)n, and
(Ser-Gly-Gly-Gly-Gly)n, wherein n=1 to 10. (Gly-Gly-Gly-Gly-Ser)n
and (Ser-Gly-Gly-Gly-Gly)n are also known as (G4S)n and (S4G)n,
respectively.
[0123] In one such embodiment of the invention, the apelin peptide
is connected to the C-terminus or to the N-terminus of the
Fc-containing polypeptide, or fragment thereof, via one or more
Gly-Ser peptide linkers.
[0124] In one embodiment, the peptide linker is
(Gly-Gly-Gly-Gly-Ser).sub.1, (Gly-Gly-Gly-Gly-Ser).sub.2,
(Gly-Gly-Gly-Gly-Ser).sub.3, or (Gly-Gly-Gly-Gly-Ser).sub.4. In one
embodiment, the peptide linker comprises
(Gly-Gly-Gly-Gly-Ser).sub.3 (SEQ ID NO: 11).
[0125] In some embodiments, the signal peptide is connected to the
N-terminus of the Fc-fusion polypeptide via one or more peptide
linkers or spacers. In some embodiments, the signal peptide is
encoded upstream of the Fc-fusion protein in an expression vector
and a spacer is encoded in-frame between the signal peptide and
N-terminus of the Fc-fusion protein. In another embodiment, the
peptide linker or spacer comprises RSTGSPGSG (SEQ ID NO: 12).
Modified Apelin Fusion Polypeptides
[0126] In other embodiments, the sequence of any Fc-fusion protein
of the invention may be modified so that it does not comprise any
acceptor sites for N-linked glycosylation. In still other
embodiments, the sequence of any Fc-fusion protein of the invention
may be modified to enhance or diminish antibody binding to the FcRn
receptor, e.g., at acidic pH as compared to neutral pH. In other
embodiments, the sequence of any Fc-fusion protein of the invention
may be modified to resist cleavage or degradation. As such,
addition of one or more C-terminal amino acids to the apelin
peptide of an apelin-Fc-fusion protein may confer increased
stability, such as resistance to degradation. Without being bound
by one theory, additional C-terminal amino acids may eliminate
susceptibility to cleavage sites within the peptide or fusion
protein. Stability may be conferred due to decreased or slowed
clearance from the circulation (i.e. renal excretion or clearance).
Such modifications to apelin peptides do not alter their ability to
activate the APLNR. Exemplary modified apelin peptides are included
in Tables 3 and 4, e.g. SEQ ID NO: 38, SEQ ID NO: 42, SEQ ID NO:
43, and SEQ ID NO: 44. Exemplary apelin fusion proteins of the
invention include SEQ ID NO: 39, SEQ ID NO: 40 and SEQ ID NO:
41.
[0127] In general, proteins, including Fc-fusion proteins described
herein may be modified by inclusion of any suitable number of such
modified amino acids (including non-standard amino acids, discussed
supra) and/or associations with conjugated substituents.
Suitability in this context is generally determined by the ability
to at least substantially retain the Fc-fusion protein's associated
selectivity and/or specificity, for example binding to APLNR. The
modified amino acid may, for instance, be selected from a
glycosylated amino acid, a PEGylated amino acid, a farnesylated
amino acid, a geranyl-geranylated amino acid, an acetylated amino
acid, a biotinylated amino acid, an amino acid conjugated to a
lipid moiety, or an amino acid conjugated to an organic
derivatizing agent, or the like. The inclusion of one or more
modified amino acids may be advantageous in, for example, further
increasing polypeptide serum half-life, reducing polypeptide
antigenicity, or increasing polypeptide storage stability. Amino
acid(s) are modified, for example, co-translationally or
post-translationally during recombinant production (e.g., N-linked
glycosylation at N-X-S/T motifs during expression in mammalian
cells) or modified by synthetic means. Non-limiting examples of a
modified amino acid include a glycosylated amino acid, a sulfated
amino acid, a prenylated (e.g., farnesylated, geranyl-geranylated)
amino acid, an acetylated amino acid, an acylated amino acid, a
fatty acylated amino acid, a PEGylated amino acid, a biotinylated
amino acid, a carboxylated amino acid, a phosphorylated amino acid,
and the like. References adequate to guide one of skill in the
modification of amino acids are replete throughout the literature.
Example protocols are found in Walker, 1998, Protein Protocols On
CD-Rom, Humana Press, Totowa, N.J.
[0128] Proteins, including Fc-fusion proteins of the invention may
also be chemically modified by covalent conjugation to a polymer
to, for instance, further increase their circulating half-life.
Exemplary polymers, and methods to attach them to peptides, are
illustrated in for instance U.S. Pat. No. 4,766,106, U.S. Pat. No.
4,179,337, U.S. Pat. No. 4,495,285 and U.S. Pat. No. 4,609,546.
Additional illustrative polymers include polyoxyethylated polyols
and polyethylene glycol (PEG) (e.g., a PEG with a molecular weight
of between about 1,000 and about 40,000, such as between about
2,000 and about 20,000, e.g., about 3,000-12,000 g/mol). See, e.g.,
WO2012/125408, which describes a PEG-apelin-36, a polypeptide with
prolonged inotropic effects in rats.
[0129] In one embodiment, proteins including Fc-fusion proteins
comprising one or more radiolabeled amino acids are provided. A
radiolabeled antibody may be used for both diagnostic and
therapeutic purposes. In another embodiment, proteins, including
Fc-fusion proteins of the present invention may be conjugated to a
molecule which is a therapeutic agent or a detectable marker. In
one embodiment, the therapeutic agent is a cytotoxic agent, such as
a radioisotope. Examples of radioisotopes for polypeptides include,
but are not limited to, .sup.3H, .sup.14C, .sup.15N, .sup.35S,
.sup.90Y, .sup.99Tc, and .sup.125I, .sup.131I, .sup.186Re, and
.sup.225Ac. Methods for preparing radiolabeled amino acids and
related peptide derivatives are known in the art (see for instance
Junghans et al., in Cancer Chemotherapy and Biotherapy 655-686 (2nd
edition, Chafner and Longo, eds., Lippincott Raven (1996)) and U.S.
Pat. No. 4,681,581, U.S. Pat. No. 4,735,210, U.S. Pat. No.
5,101,827, U.S. Pat. No. 5,102,990 (U.S. RE35,500), U.S. Pat. No.
5,648,471 and U.S. Pat. No. 5,697,902. For example, a radioisotope
may be conjugated by a chloramine T method. In further embodiments,
a detectable marker may be a radiolabel, an enzyme, a chromophore,
or a fluorescent label.
Expression Systems
[0130] The invention provides an expression vector encoding a
polypeptide, e.g. an apelin Fc-fusion protein of the invention.
Such expression vectors may be used for recombinant production of
polypeptides of the invention.
[0131] An expression vector in the context of the present invention
may be any suitable vector, including chromosomal, non-chromosomal,
and synthetic nucleic acid vectors (a nucleic acid sequence
comprising a suitable set of expression control elements). Examples
of such vectors include derivatives of SV40, bacterial plasmids,
phage DNA, baculovirus, yeast plasmids, vectors derived from
combinations of plasmids and phage DNA, and viral nucleic acid (RNA
or DNA) vectors. In one embodiment, an Fc-fusion protein or
polypeptide-encoding nucleic acid molecule is comprised in a naked
DNA or RNA vector, including, for example, a linear expression
element (as described in, for instance, Sykes and Johnston, Nat
Biotech 12, 355-59 (1997)), a compacted nucleic acid vector (as
described in for instance U.S. Pat. No. 6,077,835 and/or WO
00/70087), or a plasmid vector such as pBR322, pUC 19/18, or pUC
118/119. Such nucleic acid vectors and the usage thereof are well
known in the art (see, for instance, U.S. Pat. No. 5,589,466 and
U.S. Pat. No. 5,973,972).
[0132] In another embodiment, the vector comprises a nucleic acid
molecule encoding a polypeptide of the invention, including an
expression vector comprising the nucleic acid molecules described
wherein the nucleic acid molecule is operatively linked to an
expression control sequence.
[0133] In one embodiment, the vector is suitable for expression of
a polypeptide of the invention in a bacterial cell. Examples of
such vectors include expression vectors such as BlueScript
(Stratagene), pIN vectors (Van Heeke & Schuster, 1989, J Biol
Chem 264, 5503-5509), pET vectors (Novagen, Madison, Wis.) and the
like.
[0134] An expression vector may also or alternatively be a vector
suitable for expression in a yeast system. Any vector suitable for
expression in a yeast system may be employed. Suitable vectors
include, for example, vectors comprising constitutive or inducible
promoters such as yeast alpha factor, alcohol oxidase and PGH
(reviewed in: F. Ausubel et al., ed., 1987, Current Protocols in
Molecular Biology, Greene Publishing and Wiley InterScience New
York; and Grant et al., 1987, Methods in Enzymol 153, 516-544).
[0135] In other embodiments, the expression vector is suitable for
expression in baculovirus-infected insect cells. (Kost, T; and
Condreay, J P, 1999, Current Opinion in Biotechnology 10 (5):
428-33.)
[0136] A vector comprising a nucleic acid molecule of the invention
is provided, wherein the nucleic acid molecule is operably linked
to an expression control sequence suitable for expression in a
mammalian host cell.
[0137] Expression control sequences are engineered to control and
drive the transcription of genes of interest, and subsequent
expression of proteins in various cell systems. Plasmids combine an
expressible gene of interest with expression control sequences
(i.e. expression cassettes) that comprise desirable elements such
as, for example, promoters, enhancers, selectable markers,
operators, etc. In an expression vector of the invention, Fc-fusion
protein or antibody-encoding nucleic acid molecules may comprise or
be associated with any suitable promoter, enhancer, selectable
marker, operator, repressor protein, polyA termination sequences
and other expression-facilitating elements.
[0138] "Promoter" as used herein indicates a DNA sequence
sufficient to direct transcription of a DNA sequence to which it is
operably linked, i.e., linked in such a way as to permit
transcription of the Fc-fusion protein or antibody-encoding
nucleotide sequence when the appropriate signals are present. The
expression of a Fc-fusion protein or antibody-encoding nucleotide
sequence may be placed under control of any promoter or enhancer
element known in the art. Examples of such elements include strong
expression promoters (e. g., human CMV IE promoter/enhancer or CMV
major IE (CMV-MIE) promoter, as well as RSV, SV40 late promoter,
SL3-3, MMTV, ubiquitin (Ubi), ubiquitin C (UbC), and HIV LTR
promoters).
[0139] In some embodiments, the vector comprises a promoter
selected from the group consisting of SV40, CMV, CMV-IE, CMV-MIE,
RSV, SL3-3, MMTV, Ubi, UbC and HIV LTR.
[0140] Nucleic acid molecules of the invention may also be operably
linked to an effective poly (A) termination sequence, an origin of
replication for plasmid product in E. coli, an antibiotic
resistance gene as selectable marker, and/or a convenient cloning
site (e.g., a polylinker). Nucleic acids may also comprise a
regulatable inducible promoter (inducible, repressable,
developmentally regulated) as opposed to a constitutive promoter
such as CMV IE (the skilled artisan will recognize that such terms
are actually descriptors of a degree of gene expression under
certain conditions).
[0141] Selectable markers are elements well-known in the art. Under
the selective conditions, only cells that express the appropriate
selectable marker can survive. Commonly, selectable marker genes
express proteins, usually enzymes, that confer resistance to
various antibiotics in cell culture. In other selective conditions,
cells that express a fluorescent protein marker are made visible,
and are thus selectable. Embodiments include beta-lactamase (bla)
(beta--lactam antibiotic resistance or ampicillin resistance gene
or ampR), bls (blasticidin resistance acetyl transferase gene), bsd
(blasticidin-S deaminase resistance gene), bsr (blasticidin-S
resistance gene), Sh ble (Zeocin.RTM. resistance gene), hygromycin
phosphotransferase (hpt) (hygromycin resistance gene), tetM
(tetracycline resistance gene or tetR), neomycin phosphotransferase
II (npt) (neomycin resistance gene or neoR), kanR (kanamycin
resistance gene), and pac (puromycin resistance gene).
[0142] In certain embodiments, the vector comprises one or more
selectable marker genes selected from the group consisting of bla,
bls, BSD, bsr, Sh ble, hpt, tetR, tetM, npt, kanR and pac. In other
embodiments, the vector comprises one or more selectable marker
genes encoding green fluorescent protein (GFP), enhanced green
fluorescent protein (eGFP), cyano fluorescent protein (CFP),
enhanced cyano fluorescent protein (eCFP), or yellow fluorescent
protein (YFP).
[0143] For the purposes of this invention, gene expression in
eukaryotic cells may be tightly regulated using a strong promoter
that is controlled by an operator that is in turn regulated by a
regulatory protein, which may be a recombinant "regulatory fusion
protein" (RFP). The RFP consists essentially of a transcription
blocking domain, and a ligand-binding domain that regulates its
activity. Examples of such expression systems are described in
US20090162901A1, which is herein incorporated by reference in its
entirety.
[0144] As used herein "operator" indicates a DNA sequence that is
introduced in or near a gene in such a way that the gene may be
regulated by the binding of the RFP to the operator and, as a
result, prevents or allow transcription of the gene of interest,
i.e. a nucleotide encoding a polypeptide of the invention. A number
of operators in prokaryotic cells and bacteriophage have been well
characterized (Neidhardt, ed., Escherichia coli and Salmonella;
Cellular and Molecular Biology 2d. Vol 2 ASM Press, Washington D.C.
1996). These include, but are not limited to, the operator region
of the LexA gene of E. coli, which binds the LexA peptide, and the
lactose and tryptophan operators, which bind the repressor proteins
encoded by the Lacl and trpR genes of E. coli. These also include
the bacteriophage operators from the lambda P.sub.R and the phage
P22 ant/mnt genes, which bind the repressor proteins encoded by
lambda cl and P22 arc. In some embodiments, when the transcription
blocking domain of the RFP is a restriction enzyme, such as Notl,
the operator is the recognition sequence for that enzyme. One
skilled in the art will recognize that the operator must be located
adjacent to, or 3' to the promoter such that it is capable of
controlling transcription by the promoter. For example, U.S. Pat.
No. 5,972,650, which is incorporated by reference herein, specifies
that tetO sequences be within a specific distance from the TATA
box. In specific embodiments, the operator is preferably placed
immediately downstream of the promoter. In other embodiments, the
operator is placed within 10 base pairs of the promoter.
[0145] In certain embodiments, the operator is selected from the
group consisting of tet operator (tetO), Notl recognition sequence
(not familiar with this; I know Notl as a restriction enzyme), LexA
operator, lactose operator, tryptophan operator and Arc operator
(AO). In some embodiments, the repressor protein is selected from
the group consisting of TetR, LexA, Lacl, TrpR, Arc, LambdaC1 and
GAL4. In other embodiments, the transcription blocking domain is
derived from a eukaryotic repressor protein, e.g. a repressor
domain derived from GAL4. Bacterial operators can be employed in
mammalian and other host cell systems (see, e.g., US 20090162901A1,
which is herein incorporated by reference).
[0146] In an exemplary cell expression system, cells are engineered
to express the tetracycline repressor protein (TetR) and a protein
of interest is placed under transcriptional control of a promoter
whose activity is regulated by TetR. Two tandem TetR operators
(tetO) are placed immediately downstream of a CMV-MIE
promoter/enhancer in the vector. Transcription of the gene encoding
the protein of interest directed by the CMV-MIE promoter in such
vector may be blocked by TetR in the absence of tetracycline or
some other suitable inducer (e.g. doxycycline). In the presence of
an inducer, TetR protein is incapable of binding tetO, hence
transcription then translation (expression) of the protein of
interest occurs. (See, e.g., U.S. Pat. No. 7,435,553, which is
herein incorporated by reference in its entirety.)
[0147] Another exemplary cell expression system includes regulatory
fusion proteins such as TetR-ER.sub.LBDT2 fusion protein, in which
the transcription blocking domain of the fusion protein is TetR and
the ligand-binding domain is the estrogen receptor ligand-binding
domain (ER.sub.LBD) with T2 mutations (ER.sub.LBDT2; Feil et al.,
1997, Biochem. Biophys. Res. Commun. 237:752-757). When tetO
sequences were placed downstream and proximal to the strong CMV-MIE
promoter, transcription of the nucleotide sequence of interest from
the CMV-MIE/tetO promoter was blocked in the presence of tamoxifen
and unblocked by removal of tamoxifen. In another example, use of
the fusion protein Arc2-ER.sub.LBDT2, a fusion protein consisting
of a single chain dimer consisting of two Arc proteins connected by
a 15 amino acid linker and the ER.sub.LBDT2 (supra), involves an
Arc operator (AO), more specifically two tandem arc operators
immediately downstream of the CMV-MIE promoter/enhancer. Cell lines
may be regulated by Arc2-ER.sub.LBDT2, wherein cells expressing the
protein of interest are driven by a CMV-MIE/ArcO2 promoter and are
inducible with the removal of tamoxifen. (See, e.g., US
20090162901A1, which is herein incorporated by reference.)
[0148] In some embodiments, a vector of the invention comprises a
CMV-MIE/TetO or CMV-MIE/AO2 hybrid promoter.
[0149] The vectors of the invention may also employ Cre-lox
recombination tools to facilitate the integration of a gene of
interest into a host genome. A Cre-lox strategy requires at least
two components: 1) Cre recombinase, an enzyme that catalyzes
recombination between two loxP sites; and 2) loxP sites (e.g. a
specific 34-base pair bp sequence consisting of an .beta.-bp core
sequence, where recombination takes place, and two flanking 13-bp
inverted repeats) or mutant lox sites. (See, e.g. Araki et al.,
1995, PNAS 92:160-4; Nagy, A. et al., 2000, Genesis 26:99-109;
Araki et al., 2002, Nuc Acids Res 30(19):e103; and US20100291626A1,
all of which are herein incorporated by reference). In another
recombination strategy, yeast-derived FLP recombinase may be
utilized with the consensus sequence FRT (see also, e.g. Dymecki,
S. M., 1996, PNAS 93(12): 6191-6196).
[0150] In another aspect, a gene (i.e. a nucleotide sequence
encoding a recombinant polypeptide of the invention) is inserted
within an expression-enhancing sequence of the expression cassette,
and is optionally operably linked to a promoter, wherein the
promoter-linked gene is flanked 5' by a first recombinase
recognition site and 3' by a second recombinase recognition site.
Such recombinase recognition sites allow Cre-mediated recombination
in the host cell of the expression system. In some instances, a
second promoter-linked gene is downstream (3') of the first gene
and is flanked 3' by the second recombinase recognition site. In
still other instances, a second promoter-linked gene is flanked 5'
by the second recombinase site, and flanked 3' by a third
recombinase recognition site. In some embodiments, the recombinase
recognition sites are selected from a loxP site, a lox511 site, a
lox2272 site, and a FRT site. In other embodiments, the recombinase
recognition sites are different. In a further embodiment, the host
cell comprises a gene capable of expressing a Cre recombinase.
[0151] In some embodiments, the vector further comprises an
X-box-binding-protein 1 (mXBP1) gene capable of enhancing protein
production/protein secretion through control of the expression of
genes involved in protein folding in the endoplasmic reticulum
(ER). (See, e.g. Ron D, and Walter P., 2007, Nat Rev Mol Cell Biol.
8:519-529).
[0152] The term "cell" includes any cell that is suitable for
expressing a recombinant nucleic acid sequence. Cells include those
of prokaryotes and eukaryotes (single-cell or multiple-cell),
bacterial cells (e.g., strains of E. coli, Bacillus spp.,
Streptomyces spp., etc.), mycobacteria cells, fungal cells, yeast
cells (e.g. S. cerevisiae, S. pombe, P. partoris, P. methanolica,
etc.), plant cells, insect cells (e.g. SF-9, SF-21,
baculovirus-infected insect cells, Trichoplusia ni, etc.),
non-human animal cells, mammalian cells, human cells, or cell
fusions such as, for example, hybridomas or quadromas. In certain
embodiments, the cell is a human, monkey, ape, hamster, rat or
mouse cell. In other embodiments, the cell is eukaryotic and is
selected from the following cells: CHO (e.g. CHO K1, DXB-11 CHO,
Veggie-CHO), COS (e.g. COS-7), retinal cells, Vero, CV1, kidney
(e.g. HEK293, 293 EBNA, MSR 293, MDCK, HaK, BHK21), HeLa, HepG2,
WI38, MRC 5, Colo25, HB 8065, HL-60, Jurkat, Daudi, A431
(epidermal), CV-1, U937, 3T3, L cell, C127 cell, SP2/0, NS-0, MMT
cell, tumor cell, and a cell line derived from an aforementioned
cell. In some embodiments, the cell comprises one or more viral
genes, e.g. a retinal cell that expresses a viral gene (e.g. a
PER.C6.RTM. cell).
[0153] In some embodiments, the cell is a CHO cell. In other
embodiments, the cell is a CHO K1 cell.
[0154] For example, in one embodiment, the present invention
provides a host cell comprising a nucleic acid stably integrated
into the cellular genome that comprises a nucleotide sequence
coding for expression of a recombinant polypeptide of the present
invention. In another embodiment, the present invention provides a
cell comprising a non-integrated (i.e., episomal) nucleic acid,
such as a plasmid, cosmid, phagemid, or linear expression element,
which comprises a sequence coding for expression of a recombinant
polypeptide of the invention. In other embodiments, the present
invention provides a cell line produced by stably transfecting a
host cell with a plasmid comprising an expression vector of the
invention.
[0155] In a further aspect, the invention relates to a method for
producing an Fc-fusion protein of the invention, said method
comprising the steps of a) culturing a host cell of the invention
as described herein above, and b) purifying the Fc-fusion protein
(supra) from the culture media.
Therapeutic and Diagnostic Uses of the Invention
[0156] In an even further aspect, the invention relates to a
composition comprising an apelin fusion polypeptide or protein as
defined herein.
[0157] The compositions may be formulated with pharmaceutically
acceptable carriers or diluents as well as known adjuvants and
excipients in accordance with conventional techniques such as those
disclosed in Remington: The Science and Practice of Pharmacy, 19th
Edition, Gennaro, Ed., Mack Publishing Co., Easton, Pa., 1995, and
using trial and error experimentation.
[0158] The pharmaceutically acceptable carriers or diluents as well
as any other known adjuvants and excipients should be suitable for
the chosen apelin fusion or apelin Fc-fusion protein of the present
invention and the chosen mode of administration. The actual dosage
levels of the active ingredients in the pharmaceutical compositions
of the present invention may be varied so as to obtain an amount of
the active ingredient which is effective to achieve the appropriate
stability of drug substance, desired therapeutic response for a
particular patient, composition, and mode of administration. The
selected dosage level will depend upon a variety of pharmacokinetic
factors.
[0159] The pharmaceutical composition may be administered by any
suitable route and mode. Suitable routes of administering an apelin
fusion protein of the present invention in vivo are well known in
the art and may be selected by those of ordinary skill in the art.
(Daugherty, A L, and Msrny, R J, 2006, Adv Drug Delivery Rev,
58(5-6): 686-706).
[0160] Apelin fusion proteins are agents administered for the
management of cardiovascular conditions, such as inotropic agents,
specifically positive inotropic agents. Without being bound to a
particular theory, positive inotropic agents increase myocardial
contractility, and are used to support cardiac function in
conditions such as congestive heart failure, myocardial infarction,
cardiomyopathy, and others. (See Dai, et al., 2006, Eur J Pharmacol
553(1-3): 222-228; Maguire, et al, Hypertension. 2009; 54:598-604;
and Berry, M., et al., 2004 Circulation, 110:11187-11193.)
Apelin-induced vasodilation may be protective in
ischemia-reperfusion injury. Promotion of angiogenesis and
induction of larger nonleaky vessels by apelin peptides may
contribute to functional recovery from ischemia. (Eyries M, et al.,
2008, Circ Res 103:432-440; Kidoya H, et al., 2010, Blood
115:3166-3174).
[0161] Apelin receptor agonists are considered pro-angiogenic
agents which are administered to increase cardiac output, improve
cardiac function, stabilize cardiac function, limit a decrease in
cardiac function, or promote new blood vessel growth in an ischemic
or damaged area of the heart or other tissue. Thus, apelin receptor
agonists of the invention are useful to promote angiogenesis and
therefore treat ischemia, restore bloodflow to ischemic organs and
tissues, for example to treat limb ischemia, peripheral ischemia,
renal ischemia, ocular ischemia, cerebral ischemia, or any ischemic
disease.
[0162] Apelin fusion proteins of the invention are agents
administered to increase blood flow, or increase heart
contractility, such as to treat or alleviate ischemia and heart
failure.
[0163] Apelin fusion proteins are agents administered to treat or
alleviate ischemia and reperfusion injury, such as to limit
ischemia/reperfusion (I/R) injury or delay the onset of necrosis of
the heart tissue, or to provide preventive treatment, for example,
to protect the heart from ischemia/reperfusion (I/R) injury,
improve cardiac function, or limit the development myocardial
infarction.
[0164] Apelin fusion proteins are agents administered for the
management of metabolic conditions related to diabetes and obesity.
Apelin improves glucose tolerance and enhances glucose utilization,
by muscle tissue, in obese insulin-resistant mice (Dray et al.,
2008, Cell Metab 8:437-445). Apelin KO mice have diminished insulin
sensitivity (Yue at al., 2010, Am J Physiol Endocrinol Metab
298:E59-E67). As such, Apelin fusion proteins are agents
administered to improve glucose-tolerance in the treatment of
insulin-resistant diabetes.
[0165] Changes in muscle apelin mRNA levels are also correlative
with whole-body insulin sensitivity improvements (Besse-Patin, A.
et al., 2013 Aug. 27, Int J Obes (Lond). doi: 10.1038/ijo.2013.158,
Epub ahead of print). Due to such metabolic improvements in muscle
tissue, and apelin-induced vasodilation, agonistic apelin fusion
proteins may also be administered to stimulate muscle growth and
endurance.
[0166] It has been shown that primary HIV-1 isolates can also use
APLNR as a coreceptor and synthetic apelin peptides inhibited HIV-1
entry into CD4-APLNR-expressing cells (Cayabyab, M., et al., 2000,
J. Virol., 74: 11972-11976). Apelin fusion proteins are
administered to treat HIV infection.
[0167] Apelin-neuroprotection is also seen where apelin peptides
act through signaling pathways to promote neuronal survival (Cheng,
B, et al., 2012, Peptides, 37(1):171-3). Apelin fusion proteins are
administered to promote or increase survival of neurons.
[0168] An apelin receptor agonist is also described as a hot flash
suppressant. (See WO2012/133825, published Oct. 4, 2012.) Apelin
fusion proteins of the invention may also be administered to treat,
improve or suppress hot flash symptoms in a subject.
[0169] Apelin peptide may promote obesity through adipose tissue
expansion. Apelin is induced by hypoxia and drives angiogenesis
within the hypoxic interior of expanding adipose tissue. (Kunduzova
O, et al., 2008, FASEB J, 22:4146-4153). Some apelin fusion
proteins however are antagonists of the APLNR that act as
inhibiting agents of this mechanism, in a tissue-specific manner,
to promote weight loss or treat obesity. Therefore, apelin fusion
proteins are blocking agents administered to treat obesity and to
promote weight loss.
[0170] Pathological angiogenesis, involved in promoting tumor
growth or neovascularization in the retina may be responsive to
apelin or APLNR antagonist. (Kojima, Y. and Quertermous, T., 2008,
Arterioscler Thromb Vasc Biol, 28:1687-1688; Rayalam, S. et al.
2011, Recent Pat Anticancer Drug Discov 6(3):367-72). As such,
apelin fusion proteins are inhibiting agents administered to slow
tumor growth or metastasis, or to treat cancer and metastatic
disease. Apelin fusion proteins are also administered to treat
retinopathy.
[0171] APLNR antagonists may also reduce angiogenesis and improve
function, such as in fibrotic tissues, by ameliorating the effects
of an overactive apelin system caused by a pathogenic disease
(Principe, et al., 2008; Reichenbach, et al., 2012, JPET
340(3):629-637). Without being bound by any one theory, blocking
the apelin system may slow the formation of excess fibrous
connective tissue in an organ or tissue in a reparative or reactive
process, such as in a pathological condition like cirrhosis. As
such, apelin fusion proteins may be used as inhibiting agents
administered to slow or prevent the progression of fibrosis, or to
treat fibrosis.
[0172] In some embodiments, Fc-fusion proteins of the invention
provide a method for the treatment of a disease or condition, the
method comprising administering to a subject in need thereof a
therapeutically effective amount of an apelin fusion protein
sufficient to treat the disease or condition.
[0173] In one embodiment, provided herein is a method for treatment
of a disease or condition related to apelin in a subject in need
thereof, the method comprising administering to the subject a
therapeutically effective amount of an apelin fusion protein.
[0174] In some embodiments, the apelin fusion protein comprises a
polypeptide comprising an apelin peptide fused to an Fc domain, or
a fragment thereof.
[0175] Diseases or conditions are selected from the group
consisting of cardiovascular disease, acute decompensated heart
failure, congestive heart failure, myocardial infarction,
cardiomyopathy, ischemia, ischemia/reperfusion injury, pulmonary
hypertension, diabetes, obesity, cancer, metastatic disease, fluid
homeostasis, pathological angiogenesis, retinopathy, and HIV
infection.
[0176] In some embodiments, the apelin fusion protein is an APLNR
agonist useful for treating a disease or condition selected from
the group consisting of cardiovascular disease, acute decompensated
heart failure, congestive heart failure, myocardial infarction,
cardiomyopathy, ischemia, ischemia/reperfusion injury, pulmonary
hypertension, diabetes, hot flash symptoms, fluid homeostasis, and
HIV infection. In another embodiment, the apelin fusion protein is
an APLNR agonist that promotes neuronal cell survival. In another
embodiment, the apelin fusion protein is an APLNR agonist that
decreases sensitivity to insulin.
[0177] In some embodiments, the apelin fusion protein is an APLNR
antagonist useful for treating a disease or condition selected from
the group consisting of obesity, cancer, metastatic disease,
retinopathy, fibrosis, and pathological angiogenesis. In one
embodiment, the apelin fusion protein is an APLNR antagonist that
promotes weight loss. In one embodiment, the apelin fusion protein
is an APLNR antagonist that decreases pathological angiogenesis or
neovascularization. In other embodiments, the apelin fusion protein
is an APLNR antagonist that decreases or inhibits tumor growth.
[0178] As used herein, a "therapeutically effective amount" of an
Fc-fusion protein means an amount sufficient to ameliorate,
alleviate or partially arrest the clinical manifestations of a
given disease and its complications in a therapeutic intervention
comprising the administration of said protein. An amount adequate
to accomplish this is defined as "therapeutically effective
amount". Effective amounts for each purpose will depend on the
severity of the disease or injury as well as the weight and general
state of the subject.
[0179] In the present context, the term "treatment" and "treating"
means the management and care of a patient for the purpose of
combating a condition, such as a disease or a disorder. The term is
intended to include the full spectrum of treatments for a given
condition from which the patient is suffering, such as
administration of the active ingredient (Fc-fusion protein) to
alleviate or relieve symptoms and/or complications, to delay the
progression of the disease, disorder or condition, and/or to remedy
or eliminate the disease, disorder or condition as well as to
prevent the condition, wherein prevention is to be understood as
the management and care of a patient for the purpose of stopping
the disease progression, and includes the administration of the
active ingredients to prevent the onset of the symptoms or
complications. Nonetheless, preventive, palliative, and therapeutic
(curative) treatments are each aspects of the invention. The
subject to be treated is a mammal, in particular a human being.
[0180] In some embodiments, the treatment is maintenance treatment,
recurrence prevention or stabilization of the disease or
condition.
[0181] The present invention includes compositions and therapeutic
formulations comprising any of the apelin fusion proteins described
herein in combination with one or more additional therapeutically
active components, and methods of treatment comprising
administering such combinations to subjects in need thereof.
[0182] Such additional therapeutically active components include
VEGF inhibitors, blood pressure medication, calcium channel
blockers, digitalis, anti-arrhythmics, ACE inhibitors,
anti-coagulants, immunosuppressants, pain relievers, vasodilators,
etc.
[0183] The apelin fusion proteins of the invention provide agents
with improved pharmacokinetic properties, such as circulating serum
half-life and stability compared to apelin peptides that do not
have an Fc domain or fragment of an Fc domain. In one embodiment,
the apelin fusion protein post-injection serum level is increased
or elevated for more than about 1 hour, or more than about 2 hours,
or more than about 3 hours, or more than about 4 hours, or more
than about 5 hours, or more than about 10 hours, or more than about
24 hours. In other embodiments, the apelin fusion protein has a
serum or plasma half-life of more than about 10 minutes, or more
than about 1 hour, or more than about 2, 3, 4, 5, 6, 7, 8, 9, or
more than about 10 hours, or more than about 24 hours.
[0184] Labeled apelin fusion proteins of the invention can be used
for diagnostic purposes to detect, diagnose, or monitor diseases or
disorders. The invention provides for the detection or diagnosis of
a disease or disorder, comprising: (a) assaying the existence of
apelin receptor (APLNR) in cells or tissue samples of a subject
using one or more apelin fusion proteins that immunospecifically
bind to the target APLNR; and (b) comparing the level of the APLNR
with a control level, e.g. levels in normal tissue samples, whereby
an increase in the assayed level of APLNR compared to the control
level of APLNR is indicative of the disease or disorder, or
indicative of the severity of the disease or disorder.
[0185] Apelin fusion proteins of the invention can be used to assay
APLNR levels in a biological sample using immunohistochemical
methods well-known in the art. Other apelin-based methods useful
for detecting APLNR protein include immunoassays such as the enzyme
linked immunoassay (ELISA) and the radioimmunoassay (RIA). Suitable
apelin fusion protein labels may be used in such kits and methods,
and labels known in the art include enzyme labels, such as alkaline
phophatase and glucose oxidase; radioisotope labels, such as iodine
(.sup.125I, .sup.131I), carbon (.sup.14C), sulfur (.sup.35S),
tritium (.sup.3H), indium (121In) and technetium (.sup.99mTc); and
luminescent labels, such as luminol and luciferase; and fluorescent
labels, such as fluorescein and rhodamine.
[0186] Presence of labeled apelin fusion proteins may be detected
in vivo for diagnosis purposes. In one embodiment, diagnosis
comprises: a) administering to a subject an effective amount of a
labeled apelin fusion proteins; b) waiting for a time interval
following administration for permitting labeled apelin fusion
protein to concentrate at sites where APLNR may be detected and to
allow for unbound labeled apelin fusion protein to be cleared to
background level; c) determining a background level; and d)
detecting the labeled apelin fusion protein in the subject, such
that detection of labeled apelin fusion protein above the
background level is indicative that the subject has increased APLNR
protein, or has the disease or disorder, or the increase APLNR
protein is indicative of the severity of the disease or disorder.
In accordance with such embodiment, the apelin fusion protein is
labeled with an imaging moiety suitable for detection using a
particular imaging system known to those skilled in the art.
Background levels may be determined by various methods known in the
art, including comparing the amount of labeled apelin fusion
protein detected to a standard value previously determined for a
particular imaging system. Methods and systems that may be used in
the diagnostic methods of the invention include, but are not
limited to, computed tomography (CT), whole body scan such as
positron emission tomography (PET), magnetic resonance imaging
(MRI), and sonography.
[0187] The invention also provides a pack or kit (e.g., a
pharmaceutical pack or kit) comprising one or more containers
filled with at least one activating fusion protein of the
invention. The kits of the invention may be used in any applicable
method, including, for example, diagnostically. Optionally
associated with such container(s) can be a notice in the form
prescribed by a governmental agency regulating the manufacture, use
or sale of pharmaceuticals or biological products, which notice
reflects (a) approval by the agency of manufacture, use or sale for
human administration, (b) directions for use, or (c) both approval
for manufacture and directions for use.
Ex Vivo and In Vivo Assays
[0188] Apelin Fc-fusion proteins of the invention maintain
substantial activity with respect to the APLNR while prolonging
serum half-life. APLNR signal transduction provides the nexus
between apelin Fc-fusion proteins and the known therapeutic and
biological effects of apelin. Therefore, any demonstration of an
apelin Fc-fusion protein effect on APLNR activity in vitro, ex
vivo, or in vivo provides reasonable evidence of an in vivo
biological or medical effect of the apelin Fc-fusion protein in a
patient or animal. Among other studies, it has been demonstrated
that apelin/APLNR is an endogenous protective system against
myocardial ischemia/reperfusion (I/R) injury and the anti-apoptotic
effects of apelin/APLNR activation, specifically pERK, protects
against such injury (Zeng, et al. 2009, Peptides, 30(6):1144-52,
epub Feb. 24, 2009).
[0189] Agonists of APLNR, including endogenous apelin peptides,
apelin analogues, and modified apelin peptides, demonstrate
therapeutic activity in a number of in vivo assays (e.g.
PEG-apelin-36, as in WO2012125408, and non-peptidic apelin agonists
as in Iturrioz, X. et al. 2010, FASEB J, 24(5):1506-17. Epub Dec.
29, 2009).
[0190] APLNR agonism has been demonstrated to result in increased
heart rate and cardiac contractility (Ashley, E A, et. al. 2005,
Cardiovasc Res. 65(1):73-82). In addition, apelin peptide has been
demonstrated to alter the electrophysiology of cardiomyocytes.
Whole-cell patch-clamp techniques were used to investigate the
action potential (AP) and ionic currents in isolated rabbit left
atrial (LA) myocytes before and after the administration of apelin
(See, e.g., Farkasfalvi, K., et al., 2007, Biochem Biophys Res
Commun. 357(4):889-95. Epub 2007 April 12; and Cheng, C C, et al.,
2013, Eur J Clin Invest. 43(1):34-40. Epub Oct. 28, 2012; which are
both incorporated by reference herein). Isotropy induced by apelin
agonism may also be assessed by measuring ECG parameters in
isolated hearts from mice or rats using a Langendorf or Working
Heart System. Such electrophysiological and in vivo techniques,
such as micro-ultrasound or echocardiography, are used to assess
the therapeutic action of the polypeptides of the invention.
[0191] The protective effects of apelin Fc-fusion polypeptides may
be assessed following myocardial ischemia/reperfusion (I/R) injury
or hypoxia/re-oxygenation (H/R) in isolated rat or mouse hearts as
in the Langendorf system (see e.g. Zeng, et al. 2009, Peptides,
30(6):1144-52, epub Feb. 24, 2009; Pisarenko, et al. 2010,
Kardiologiia, 50(10):44-9; and Pisarenko, et al., 2013, J Pharmacol
Pharmacother. "Effects of structural analogues of apelin-12 in
acute myocardial infarction in rats", epub before print).
[0192] Transient LAD ligation may also be performed, with apelin
agonist administered prior to reperfusion. (See Pisarenko, et al.
2011, Bull Exp Biol Med. 152(1):79-82; Li, L. et al, 2012, Am J
Physiol Heart Circ Physiol, 303(5):H605-18, Epub Jun. 29, 2012; and
Tao, J., et al, 2011, Am J Physiol Heart Circ Physiol,
301(4):H1471-86, Epub Jul. 29, 2011.) Following cardiac injury,
microultrasound parameters may be used to measure cardiac function
with respect to improvement, as well as assessment of infarct
size.
[0193] The following examples are provided to describe to those of
ordinary skill in the art how to make and use methods and
compositions of the invention, and are not intended to limit the
scope of what the inventors regard as their invention. Efforts have
been made to ensure the accuracy with respect to numbers used (e.g.
amounts, concentrations, temperature, etc.) but some experimental
errors and deviations should be accounted for.
EXAMPLES
Example 1--Cloning of Expression Constructs
[0194] Synthetic gene fragments were used to generate N-terminal
and C-terminal hFc fusions with apelin-13. DNA encoding the
resulting fusions, hFc-Apelin13 (SEQ ID NO: 1) and Apelin13-hFc
(SEQ ID NO: 3), were inserted into expression vectors downstream of
a CMV promoter, using standard molecular cloning techniques. CHO
stable cell lines were generated and used for the production of
fusion proteins, which were then purified by affinity methods.
N-terminal hFc-Apelin13 and C-terminal Apelin13-hFc fusion proteins
migrate on SDS-PAGE gels consistent with their predicted mass. (See
FIG. 3A.) Western blot analysis, performed with the anti-apelin
antibody (Abcam, #ab59469), was used to confirm presence of apelin
on hFc-Apelin13 and Apelin13-hFc. (See FIG. 3B.)
Example 2--Potency and Efficacy of Apelin Fc Fusion Proteins in a
cAMP-Reporter Assay
[0195] Modulation of intraceullular cAMP levels by unmodified
apelin peptide (Bachem, # H-4568.0001) and apelin 13 fusion
proteins of the invention was evaluated using a bioassay that was
developed to detect the activation of hAPLNR. A HEK293 cell line
was transfected to stably express the full-length human hAPLNR
(amino acids 1-380 of accession number NP 005152.1), along with a
luciferase reporter [cAMP response element
(CRE,4.times.)-luciferase]. The resulting cell line,
HEK293/CRE-luc/hAPLNR, was maintained in DMEM containing 10% FBS,
NEAA, pencillin/streptomycin, and 100 .mu.g/mL hygromycin B. For
the bioassay, HEK293/CRE-luc/hAPLNR cells were seeded onto 96-well
assay plates at 20,000 cells/well in 80 .mu.L of OPTIMEM
supplemented with 0.1% FBS and penicillin/streptomycin/L-glutamine
and incubated for 16 hours at 37.degree. C. in 5% CO.sub.2. The
next morning, to measure inhibition of forskolin-induced cAMP
production via hAPLNR activation, unmodified apelin peptide and
apelin 13 fusion proteins were serially diluted (1:3) then mixed
with forskolin (Sigma, # F6886) in assay buffer (5 .mu.M final
forskolin concentration), and added to the cells. After 5 hours of
incubation at 37.degree. C. in 5% CO.sub.2, luminescence was
measured following the addition of One Glo reagent (Promega, #
E6051) using a Victor X instrument (Perkin Elmer). The data were
fit by nonlinear regression to a 4-parameter logistic equation with
Prism 5 software (GraphPad).
[0196] The hFc-Apelin13 fusion protein promoted inhibition of cAMP
release from forskolin-stimulated HEK293/CRE-luc/hAPLNR cells with
an EC.sub.50 value of 174 .rho.M and Apelin13-hFc activated with an
EC.sub.50 value of 22.1 nM. In this assay, apelin-13 activated with
an EC.sub.50 value of 36.5 .rho.M. (See FIG. 4.)
Example 3--Potency and Efficacy of Fc Fusion Proteins in a
.beta.-Arrestin Assay
[0197] The DiscoverX PathHunter.RTM. platform is based on the
recruitment of .beta.-arrestin to GPCRs in response to treatment
with a relevant ligand. In this assay format, .beta.-arrestin is
fused to an N-terminal deletion mutant of .beta.-galactosidase
(.beta.-gal) and stably-expressed in the cells whereas the GPCR is
fused to a smaller (42 amino acids), weakly complementing
.beta.-gal fragment. Ligand stimulation of the GPCR in this assay
results in the recruitment of .beta.-arrestin to the GPCR, forcing
the complementation of the two .beta.-gal fragments and resulting
in the formation of a functional enzyme that converts substrate to
detectable signal (DiscoverX Corporation, Fremont, Calif.,
USA).
[0198] For the assay, CHO-K1/hAPLNR DiscoverX cells were plated at
10,000 cells per well in assay media (DiscoverX Corporation;
#93-0250E2) and incubated for 48 hours at 37.degree. C. in 5%
CO.sub.2. Cells were then treated with a 1:10 serial dilution of
either unmodified apelin-13 peptide or the apelin-13 fusion
proteins. After 1.5 hours of incubation at 37.degree. C., detection
reagents were added as per the manufacturer's specifications and
incubated for 1 hour at RT, followed by luminescence measurement
using a Victor instrument (Perkin-Elmer)
[0199] The hFc-Apelin13, apelin-13, and Apelin13-hFc proteins
activated CHO-K1/hAPLNR DiscoverX cells in a dose-dependent manner,
with EC.sub.50 values of 992 .rho.M, 17.6 .rho.M, and 44.2 nM
(extrapolated value), respectively (FIG. 5).
Example 4--Potency and Efficacy of Fc Fusion Proteins in a pERK
Assay
[0200] To measure the effect of the apelin-13 fusion proteins of
the invention on the APLNR signaling pathway, an assay was used to
quantify the amount of phosphorylated ERK1/2 (pERK1/2) and total
ERK from an APLNR expressing cell line. A Chinese hamster ovary
(CHO) cell line was transfected to stably express the full-length
human APLNR (hAPLNR; amino acids 1-380 of accession number
NP_005152.1) under the control of a doxycycline-inducible CMV
promoter. The resulting cell line, CHO/hAPLNR was maintained in
Ham's F12 media containing 10% FBS, penicillin/streptomycin,
L-glutamine, and 250 ug/mL hygromycin B.
[0201] For the assay, CHO/hAPLNR cells were seeded onto 96 well
assay plates at 10,000 cells/well in 200 .mu.L of Ham's F12
containing 10% FBS, L-glutamine, penicillin/streptomycin and
incubated at 37.degree. C. in 5% CO.sub.2 for 24 hours. The next
day, to induce expression of the APLNR and prepare the cells for
the pERK assay, the cells were first washed once with 250 .mu.l of
1.times.PBS (Life Technologies; #20012-043), then serum-starved in
Ham's F12 containing 0.1% FBS, 1% BSA, L-glutamine,
penicillin/streptomycin, 0.5 .mu.g/mL doxycycline for 24 hours. On
the day of the assay, cells were treated with a 1:10 serial
dilution of either unmodified apelin peptide or fusion proteins in
Ham's F12 supplemented with 1% BSA, penicillin/streptomycin,
L-glutamine for 15 minutes at 37.degree. C. in 5% CO.sub.2. At the
end of the incubation, cells were washed with 200 .mu.L of PBS and
subsequently lysed with 100 uL of ELISAone Lysis Buffer (TGR
BioSciences; #EBF001). Extracts were then analyzed for
phosphorylated ERK (pERK1/2) and total ERK levels, as per the
manufacturer's specifications (TGR Biosciences, #EKT001). The
fluorescence signals were then measured using a Spectramax plate
reader (Molecular Devices). The ratio of measured pERK1/2 to
measured total ERK was calculated and the results were analyzed
using GraphPad Prism.
[0202] In the pERK assay, hFc-Apelin13 and Apelin13-hFc increased
the ratio of pERK1/2 to total ERK1/2 in CHO/hAPLNR cells in a
dose-dependent manner, with EC.sub.50 values of 216 pM and 33 nM,
respectively (FIG. 6).
Example 6--Pharmacokinetic Study to Evaluate Serum Stability of Fc
Fusions
[0203] C57/Bl6 mice (n=3 per group) were dosed subcutaneously
(s.c.) with hFc (2.5 mg/kg) or Apelin13-hFc (2.8 mg/kg) (FIG. 7A)
and plasma was collected at 1, 4, 24, and 48 hours. In a separate
experiment, hFc-Apein13 was injected s.c. in C57/Bl6 mice (n=3 per
group) at 5 mg/kg and serum was collected in 0, 1, 2, 4, 5, 6, 24
hours and 2, 3, 7, 14, 21 days (FIG. 7B).
[0204] To evaluate serum/plasma levels of the administered
proteins, 96-well ELISA plates were coated for 18 hrs at 4.degree.
C. with a 100 .mu.L/well of goat anti-human IgG antibody (Jackson
ImmunoLab; 109-005-098) at a concentration of 1 .mu.g/mL in PBS.
The plates were subsequently blocked for 1 hour at room temperature
(RT) with 300 .mu.L/well of 1.times.milk diluent/blocking solution
(KPL; #100108). Dilutions of hFc (for standard curve) and serum
samples in 100 .mu.L of diluent were then added to the plate. After
incubating for 2 hours at RT, the wells were then washed, and
plate-bound human Fc was detected by addition of a horse-radish
peroxidase conjugated anti-human IgG antibody (Jackson ImmuLab;
#109-035-098) to the plate for 7 minutes at RT. Samples were
developed for 7 minutes with a TMB solution (MP Biomedical;
#152346) to produce a colorimetric reaction and then neutralized
with 100 .mu.L/well of 2.0N H.sub.2SO.sub.4 (Mallinckrodt; #
H381-05) before measuring absorbance at 450 nm wavelength on a
Spectramax plate reader (Molecular Devices). Data were analyzed
using SoftMax software to determine concentrations of the samples
in serum.
[0205] Apelin13-hFc serum levels reached a maximum of 10 .mu.g/mL
(380 nM) at .about.4 hours and remained comparable to those of hFc
after 48 hrs (FIG. 7A). The hFc-Apelin13 serum levels reached a
maximum of 3 .mu.g/mL (100 nM) at 24 hours and gradually decreased
to 1 .mu.g/mL (38 nM) at day 14 (FIG. 7B).
Example 7--Potency and Efficacy of Apelin Peptides in a CRE
Assay
[0206] Apelin-13 having an Fc tethered to its N-terminus
(hFc-Apelin13) displays better potency than Apelin-13 having Fc
tethered to its C-terminus (Apelin-hFc), as seen in above Examples
2 through 6. Modified Apelin-13 peptides, such as Apelin-13
peptides having one or more amino acid(s) deleted from or added to
the N-terminus or C-terminus, were tested for their relative
potencies with respect to APLNR activation.
[0207] Modulation of cAMP levels by unmodified apelin-13 peptide
(Bachem, # H-4568.0001) and modified apelin peptides of the
invention were evaluated using a bioassay that was developed to
detect the activation of hAPLNR, according to the method of Example
2 (supra). The results were analyzed using nonlinear regression
(4-parameter logistics) with Prism 5 software (GraphPad).
[0208] As shown in Table 3, apelin-13 can tolerate deletions of
amino acids from both the N-terminus and C-terminus while still
retaining full efficacy, and displaying different degrees of
reduced potency compared to apelin-13. Furthermore, apelin-13 can
tolerate the addition of amino acid residues to its C-terminus,
such as five glycine residues, and still retain full efficacy but
with reduced potency, relative to apelin-13. It is envisioned that
similar variations of Fc-apelin fusion proteins will maintain their
efficacy.
TABLE-US-00003 TABLE 3 Apelin Peptides and Derivatives Maintain
Efficacy in CRE Assay Apelin Peptide Amino Acid Sequence EC.sub.50
(M) Apelin-13 QRPRLSHKGPMPF 1.403e-013 (SEQ ID NO: 6) Apelin-F13A
QRPRLSHKGPMPA 1.027e-010 (SEQ ID NO: 29) Apelin65-76 QRPRLSHKGPMP
5.713e-011 (SEQ ID NO: 30) Apelin65-75 QRPRLSHKGPM 3.604e-012 (SEQ
ID NO: 31) Apelin-12 RPRLSHKGPMPF 8.704e-013 (SEQ ID NO: 32)
Apelin-11 PRLSHKGPMPF 4.379e-010 (SEQ ID NO: 33) Apelin66-76
RPRLSHKGPMP 5.194e-012 (SEQ ID NO: 34) Apelin67-76 PRLSHKGPMP
1.137e-013 (SEQ ID NO: 35) Apelin66-75 RPRLSHKGPM 2.174e-012 (SEQ
ID NO: 36) Apelin67-75 PRLSHKGPM 3.738e-007 (SEQ ID NO: 37)
Apelin-13 + 5G QRPRLSHKGPMPFGGGGG 1.469e-010 (SEQ ID NO: 38)
Example .beta.--Potency and Efficacy of Modified Apelin Fusion
Proteins in a CRE Assay
[0209] Various apelin-Fc fusion proteins were made analogously to
Example 1, except having modified apelin peptides, such as SEQ ID
NO: 42, SEQ ID NO: 43 and SEQ ID NO:44, fused to the hFc. Such
hFc-Apelin13 fusion proteins have an additional C-terminal amino
acid at the C-terminus of the apelin peptide component. Modulation
of cAMP levels by apelin-13 peptide compared to these modified
Apelin-13 peptides with hFc tethered to its N-terminus
(hFc-Apelin13+) were evaluated using the CRE bioassay analogously
to the methods of Example 2 and Example 7 (supra). The results were
analyzed using nonlinear regression (4-parameter logistics) with
Prism 5 software (GraphPad).
[0210] As shown in Table 4, modified apelin fusion proteins (having
an Fc at the N-terminus and additional amino acid at the C-terminus
of the apelin peptide component) exhibit activity at the APLNR
similar to that of unmodified apelin-13. The hFc-Apelin13 fusion
protein having an additional arginine at the C-terminus activated
HEK293/CRE-luc/hAPLNR cells with an EC.sub.50 value of 60 .rho.M.
The hFc-Apelin13 fusion protein having an additional serine at the
C-terminus, and the hFc-Apelin13 fusion protein having an
additional histidine at the C-terminus, each activated APLNR with
an EC.sub.50 value of 96 .rho.M and 203 .rho.M, respectively. In
this assay, apelin-13 activated with an EC.sub.50 value of 56
.rho.M.
TABLE-US-00004 TABLE 4 Modified Apelin Fusion Proteins Maintain
Efficacy in CRE Assay Fusion SEQ ID NO: Protein tested (apelin
peptide SEQ ID NO:) EC.sub.50 (pM) apelin-13 -- (SEQ ID NO: 6) 56
hFc-Apelin13-R SEQ ID NO: 39 (SEQ ID NO: 42) 60 hFc-Apelin13-S SEQ
ID NO: 40 (SEQ ID NO: 43) 96 hFc-Apelin13-H SEQ ID NO: 41 (SEQ ID
NO: 44) 203
Example 9--Cardiovascular Evaluation of Apelin Fc Fusions
[0211] The effects of apelin Fc-fusion proteins of the invention
are assessed by electrocardiography in anesthetized mice and rats,
particularly effects on RR interval (index of heart rate) as well
as QT interval as an index of ion channel activity.
[0212] The effects of APLNR agonists on blood pressure, heart rate
and activity by radio telemetry in mice and rats are assessed for
apelin Fc-fusion proteins of the invention. This method involves
the implantation of a pressure transducer in the carotid artery to
measure aorta blood pressure, heart rate and activity, with
continuous data monitoring.
[0213] Cardiac function is also assessed by determining changes in
cardiac contractility by APLNR agonists in vivo. One method is the
use of micro-ultrasound, or echocardiography (ECG) in mice or rats.
Upon application of apelin Fc-fusion proteins in mice or rats,
alterations in left ventricle cardiac function are monitored using
measurement of left ventricle end diastolic and end systolic
volumes (EDV and ESV). Other parameters are also recorded, such as
ventricle diameters and heart rate, in order to calculate cardiac
output (CO), Ejection Fraction (EF), Stroke Volume (SV), Fractional
Shortening (FS) from recorded images of micro-ultrasound scans.
[0214] Isotropy, either induced by APNLR agonists or blocked by
antagonists, is also assessed by measuring left ventricular
pressure, and dP/dT (change in pressure over time), heart rate, and
cardiac conductance by ECG in isolated hearts from mice or rats
using a Langendorf or Working Heart system.
[0215] Myocardial ischemia/reperfusion: Effects of apelin Fc-fusion
polypeptides may be assessed following myocardial
ischemia/reperfusion (I/R) injury or hypoxia/re-oxygenation (H/R)
in isolated rat or mouse hearts as in the Langendorf system (see
e.g. Zeng, et al. 2009, Peptides, 30(6):1144-52, epub Feb. 24,
2009). Transient LAD ligation is performed, with apelin Fc-fusion
polypeptides administered prior to reperfusion. (See e.g.
Pisarenko, et al. 2011, Bull Exp Biol Med. 152(1):79-82.)
Microultrasound measures of cardiac function (described
hereinabove) are applied to determine improvement in this context.
Infarct size is assessed by standard histology techniques.
[0216] Relaxation of pre-constricted aortic rings is assessed as
follows: Ex vivo preparation of thoracic aorta from mouse or rat is
suspended by titanium wires to a force transducer. Rings are
pre-constricted with a vasoconstrictor (such as Phenylephrine,
nor-epinephrine, or nor-adrenaline, endothelin or angiotensin II).
An increase in diameter and a decrease in force as measured by the
force transducer indicates an ability to induce vasorelaxation.
(See Iturrioz, X. et al. 2010, FASEB J, 24(5):1506-17, Epub Dec.
29, 2009; and also the Multi Myograph system as in Zhong, et al.,
2007, Cardiovasc Res 74(3): 388-395.)
Sequence CWU 1
1
441293PRTArtificial SequenceSynthetic 1Met His Arg Pro Arg Arg Arg
Gly Thr Arg Pro Pro Pro Leu Ala Leu 1 5 10 15 Leu Ala Ala Leu Leu
Leu Ala Ala Arg Gly Ala Asp Ala Arg Ser Thr 20 25 30 Gly Ser Pro
Gly Ser Gly Asp Lys Thr His Thr Cys Pro Pro Cys Pro 35 40 45 Ala
Pro Glu Leu Leu Gly Gly Pro Ser Val Phe Leu Phe Pro Pro Lys 50 55
60 Pro Lys Asp Thr Leu Met Ile Ser Arg Thr Pro Glu Val Thr Cys Val
65 70 75 80 Val Val Asp Val Ser His Glu Asp Pro Glu Val Lys Phe Asn
Trp Tyr 85 90 95 Val Asp Gly Val Glu Val His Asn Ala Lys Thr Lys
Pro Arg Glu Glu 100 105 110 Gln Tyr Asn Ser Thr Tyr Arg Val Val Ser
Val Leu Thr Val Leu His 115 120 125 Gln Asp Trp Leu Asn Gly Lys Glu
Tyr Lys Cys Lys Val Ser Asn Lys 130 135 140 Ala Leu Pro Ala Pro Ile
Glu Lys Thr Ile Ser Lys Ala Lys Gly Gln 145 150 155 160 Pro Arg Glu
Pro Gln Val Tyr Thr Leu Pro Pro Ser Arg Asp Glu Leu 165 170 175 Thr
Lys Asn Gln Val Ser Leu Thr Cys Leu Val Lys Gly Phe Tyr Pro 180 185
190 Ser Asp Ile Ala Val Glu Trp Glu Ser Asn Gly Gln Pro Glu Asn Asn
195 200 205 Tyr Lys Thr Thr Pro Pro Val Leu Asp Ser Asp Gly Ser Phe
Phe Leu 210 215 220 Tyr Ser Lys Leu Thr Val Asp Lys Ser Arg Trp Gln
Gln Gly Asn Val 225 230 235 240 Phe Ser Cys Ser Val Met His Glu Ala
Leu His Asn His Tyr Thr Gln 245 250 255 Lys Ser Leu Ser Leu Ser Pro
Gly Lys Gly Gly Gly Gly Ser Gly Gly 260 265 270 Gly Gly Ser Gly Gly
Gly Gly Ser Gln Arg Pro Arg Leu Ser His Lys 275 280 285 Gly Pro Met
Pro Phe 290 2255PRTArtificial SequenceSynthetic 2Asp Lys Thr His
Thr Cys Pro Pro Cys Pro Ala Pro Glu Leu Leu Gly 1 5 10 15 Gly Pro
Ser Val Phe Leu Phe Pro Pro Lys Pro Lys Asp Thr Leu Met 20 25 30
Ile Ser Arg Thr Pro Glu Val Thr Cys Val Val Val Asp Val Ser His 35
40 45 Glu Asp Pro Glu Val Lys Phe Asn Trp Tyr Val Asp Gly Val Glu
Val 50 55 60 His Asn Ala Lys Thr Lys Pro Arg Glu Glu Gln Tyr Asn
Ser Thr Tyr 65 70 75 80 Arg Val Val Ser Val Leu Thr Val Leu His Gln
Asp Trp Leu Asn Gly 85 90 95 Lys Glu Tyr Lys Cys Lys Val Ser Asn
Lys Ala Leu Pro Ala Pro Ile 100 105 110 Glu Lys Thr Ile Ser Lys Ala
Lys Gly Gln Pro Arg Glu Pro Gln Val 115 120 125 Tyr Thr Leu Pro Pro
Ser Arg Asp Glu Leu Thr Lys Asn Gln Val Ser 130 135 140 Leu Thr Cys
Leu Val Lys Gly Phe Tyr Pro Ser Asp Ile Ala Val Glu 145 150 155 160
Trp Glu Ser Asn Gly Gln Pro Glu Asn Asn Tyr Lys Thr Thr Pro Pro 165
170 175 Val Leu Asp Ser Asp Gly Ser Phe Phe Leu Tyr Ser Lys Leu Thr
Val 180 185 190 Asp Lys Ser Arg Trp Gln Gln Gly Asn Val Phe Ser Cys
Ser Val Met 195 200 205 His Glu Ala Leu His Asn His Tyr Thr Gln Lys
Ser Leu Ser Leu Ser 210 215 220 Pro Gly Lys Gly Gly Gly Gly Ser Gly
Gly Gly Gly Ser Gly Gly Gly 225 230 235 240 Gly Ser Gln Arg Pro Arg
Leu Ser His Lys Gly Pro Met Pro Phe 245 250 255 3284PRTArtificial
SequenceSynthetic 3Met His Arg Pro Arg Arg Arg Gly Thr Arg Pro Pro
Pro Leu Ala Leu 1 5 10 15 Leu Ala Ala Leu Leu Leu Ala Ala Arg Gly
Ala Asp Ala Gln Arg Pro 20 25 30 Arg Leu Ser His Lys Gly Pro Met
Pro Phe Gly Gly Gly Gly Ser Gly 35 40 45 Gly Gly Gly Ser Gly Gly
Gly Gly Ser Asp Lys Thr His Thr Cys Pro 50 55 60 Pro Cys Pro Ala
Pro Glu Leu Leu Gly Gly Pro Ser Val Phe Leu Phe 65 70 75 80 Pro Pro
Lys Pro Lys Asp Thr Leu Met Ile Ser Arg Thr Pro Glu Val 85 90 95
Thr Cys Val Val Val Asp Val Ser His Glu Asp Pro Glu Val Lys Phe 100
105 110 Asn Trp Tyr Val Asp Gly Val Glu Val His Asn Ala Lys Thr Lys
Pro 115 120 125 Arg Glu Glu Gln Tyr Asn Ser Thr Tyr Arg Val Val Ser
Val Leu Thr 130 135 140 Val Leu His Gln Asp Trp Leu Asn Gly Lys Glu
Tyr Lys Cys Lys Val 145 150 155 160 Ser Asn Lys Ala Leu Pro Ala Pro
Ile Glu Lys Thr Ile Ser Lys Ala 165 170 175 Lys Gly Gln Pro Arg Glu
Pro Gln Val Tyr Thr Leu Pro Pro Ser Arg 180 185 190 Asp Glu Leu Thr
Lys Asn Gln Val Ser Leu Thr Cys Leu Val Lys Gly 195 200 205 Phe Tyr
Pro Ser Asp Ile Ala Val Glu Trp Glu Ser Asn Gly Gln Pro 210 215 220
Glu Asn Asn Tyr Lys Thr Thr Pro Pro Val Leu Asp Ser Asp Gly Ser 225
230 235 240 Phe Phe Leu Tyr Ser Lys Leu Thr Val Asp Lys Ser Arg Trp
Gln Gln 245 250 255 Gly Asn Val Phe Ser Cys Ser Val Met His Glu Ala
Leu His Asn His 260 265 270 Tyr Thr Gln Lys Ser Leu Ser Leu Ser Pro
Gly Lys 275 280 4255PRTArtificial SequenceSynthetic 4Gln Arg Pro
Arg Leu Ser His Lys Gly Pro Met Pro Phe Gly Gly Gly 1 5 10 15 Gly
Ser Gly Gly Gly Gly Ser Gly Gly Gly Gly Ser Asp Lys Thr His 20 25
30 Thr Cys Pro Pro Cys Pro Ala Pro Glu Leu Leu Gly Gly Pro Ser Val
35 40 45 Phe Leu Phe Pro Pro Lys Pro Lys Asp Thr Leu Met Ile Ser
Arg Thr 50 55 60 Pro Glu Val Thr Cys Val Val Val Asp Val Ser His
Glu Asp Pro Glu 65 70 75 80 Val Lys Phe Asn Trp Tyr Val Asp Gly Val
Glu Val His Asn Ala Lys 85 90 95 Thr Lys Pro Arg Glu Glu Gln Tyr
Asn Ser Thr Tyr Arg Val Val Ser 100 105 110 Val Leu Thr Val Leu His
Gln Asp Trp Leu Asn Gly Lys Glu Tyr Lys 115 120 125 Cys Lys Val Ser
Asn Lys Ala Leu Pro Ala Pro Ile Glu Lys Thr Ile 130 135 140 Ser Lys
Ala Lys Gly Gln Pro Arg Glu Pro Gln Val Tyr Thr Leu Pro 145 150 155
160 Pro Ser Arg Asp Glu Leu Thr Lys Asn Gln Val Ser Leu Thr Cys Leu
165 170 175 Val Lys Gly Phe Tyr Pro Ser Asp Ile Ala Val Glu Trp Glu
Ser Asn 180 185 190 Gly Gln Pro Glu Asn Asn Tyr Lys Thr Thr Pro Pro
Val Leu Asp Ser 195 200 205 Asp Gly Ser Phe Phe Leu Tyr Ser Lys Leu
Thr Val Asp Lys Ser Arg 210 215 220 Trp Gln Gln Gly Asn Val Phe Ser
Cys Ser Val Met His Glu Ala Leu 225 230 235 240 His Asn His Tyr Thr
Gln Lys Ser Leu Ser Leu Ser Pro Gly Lys 245 250 255 577PRTHomo
sapiens 5Met Asn Leu Arg Leu Cys Val Gln Ala Leu Leu Leu Leu Trp
Leu Ser 1 5 10 15 Leu Thr Ala Val Cys Gly Gly Ser Leu Met Pro Leu
Pro Asp Gly Asn 20 25 30 Gly Leu Glu Asp Gly Asn Val Arg His Leu
Val Gln Pro Arg Gly Ser 35 40 45 Arg Asn Gly Pro Gly Pro Trp Gln
Gly Gly Arg Arg Lys Phe Arg Arg 50 55 60 Gln Arg Pro Arg Leu Ser
His Lys Gly Pro Met Pro Phe 65 70 75 613PRTHomo sapiens 6Gln Arg
Pro Arg Leu Ser His Lys Gly Pro Met Pro Phe 1 5 10 717PRTHomo
sapiens 7Lys Phe Arg Arg Gln Arg Pro Arg Leu Ser His Lys Gly Pro
Met Pro 1 5 10 15 Phe 836PRTHomo sapiens 8Leu Val Gln Pro Arg Gly
Ser Arg Asn Gly Pro Gly Pro Trp Gln Gly 1 5 10 15 Gly Arg Arg Lys
Phe Arg Arg Gln Arg Pro Arg Leu Ser His Lys Gly 20 25 30 Pro Met
Pro Phe 35 929PRTMus musculus 9Met His Arg Pro Arg Arg Arg Gly Thr
Arg Pro Pro Pro Leu Ala Leu 1 5 10 15 Leu Ala Ala Leu Leu Leu Ala
Ala Arg Gly Ala Asp Ala 20 25 10937PRTMus musculus 10Met His Arg
Pro Arg Arg Arg Gly Thr Arg Pro Pro Pro Leu Ala Leu 1 5 10 15 Leu
Ala Ala Leu Leu Leu Ala Ala Arg Gly Ala Asp Ala Gln Glu Thr 20 25
30 Glu Leu Ser Val Ser Ala Glu Leu Val Pro Thr Ser Ser Trp Asn Thr
35 40 45 Ser Ser Glu Ile Asp Lys Gly Ser Tyr Leu Thr Leu Asp Glu
Pro Met 50 55 60 Asn Asn Ile Thr Thr Ser Leu Gly Gln Thr Ala Glu
Leu His Cys Lys 65 70 75 80 Val Ser Gly Asn Pro Pro Pro Ser Ile Arg
Trp Phe Lys Asn Asp Ala 85 90 95 Pro Val Val Gln Glu Pro Arg Arg
Ile Ser Phe Arg Ala Thr Asn Tyr 100 105 110 Gly Ser Arg Leu Arg Ile
Arg Asn Leu Asp Thr Thr Asp Thr Gly Tyr 115 120 125 Phe Gln Cys Val
Ala Thr Asn Gly Lys Lys Val Val Ser Thr Thr Gly 130 135 140 Val Leu
Phe Val Lys Phe Gly Pro Pro Pro Thr Ala Ser Pro Gly Ser 145 150 155
160 Ser Asp Glu Tyr Glu Glu Asp Gly Phe Cys Gln Pro Tyr Arg Gly Ile
165 170 175 Ala Cys Ala Arg Phe Ile Gly Asn Arg Thr Val Tyr Met Glu
Ser Leu 180 185 190 His Met Gln Gly Glu Ile Glu Asn Gln Ile Thr Ala
Ala Phe Thr Met 195 200 205 Ile Gly Thr Ser Ser His Leu Ser Asp Lys
Cys Ser Gln Phe Ala Ile 210 215 220 Pro Ser Leu Cys His Tyr Ala Phe
Pro Tyr Cys Asp Glu Thr Ser Ser 225 230 235 240 Val Pro Lys Pro Arg
Asp Leu Cys Arg Asp Glu Cys Glu Val Leu Glu 245 250 255 Asn Val Leu
Cys Gln Thr Glu Tyr Ile Phe Ala Arg Ser Asn Pro Met 260 265 270 Ile
Leu Met Arg Leu Lys Leu Pro Asn Cys Glu Asp Leu Pro Gln Pro 275 280
285 Glu Ser Pro Glu Ala Ala Asn Cys Ile Arg Ile Gly Ile Pro Met Ala
290 295 300 Asp Pro Ile Asn Lys Asn His Lys Cys Tyr Asn Ser Thr Gly
Val Asp 305 310 315 320 Tyr Arg Gly Thr Val Ser Val Thr Lys Ser Gly
Arg Gln Cys Gln Pro 325 330 335 Trp Asn Ser Gln Tyr Pro His Thr His
Ser Phe Thr Ala Leu Arg Phe 340 345 350 Pro Glu Leu Asn Gly Gly His
Ser Tyr Cys Arg Asn Pro Gly Asn Gln 355 360 365 Lys Glu Ala Pro Trp
Cys Phe Thr Leu Asp Glu Asn Phe Lys Ser Asp 370 375 380 Leu Cys Asp
Ile Pro Ala Cys Asp Ser Lys Asp Ser Lys Glu Lys Asn 385 390 395 400
Lys Met Glu Ile Leu Tyr Ile Leu Val Pro Ser Val Ala Ile Pro Leu 405
410 415 Ala Ile Ala Phe Leu Phe Phe Phe Ile Cys Val Cys Arg Asn Asn
Gln 420 425 430 Lys Ser Ser Ser Pro Pro Val Gln Arg Gln Pro Lys Pro
Val Arg Gly 435 440 445 Gln Asn Val Glu Met Ser Met Leu Asn Ala Tyr
Lys Pro Lys Ser Lys 450 455 460 Ala Lys Glu Leu Pro Leu Ser Ala Val
Arg Phe Met Glu Glu Leu Gly 465 470 475 480 Glu Cys Thr Phe Gly Lys
Ile Tyr Lys Gly His Leu Tyr Leu Pro Gly 485 490 495 Met Asp His Ala
Gln Leu Val Ala Ile Lys Thr Leu Lys Asp Tyr Asn 500 505 510 Asn Pro
Gln Gln Trp Thr Glu Phe Gln Gln Glu Ala Ser Leu Met Ala 515 520 525
Glu Leu His His Pro Asn Ile Val Cys Leu Leu Gly Ala Val Thr Gln 530
535 540 Glu Gln Pro Val Cys Met Leu Phe Glu Tyr Met Asn Gln Gly Asp
Leu 545 550 555 560 His Glu Phe Leu Ile Met Arg Ser Pro His Ser Asp
Val Gly Cys Ser 565 570 575 Ser Asp Glu Asp Gly Thr Val Lys Ser Ser
Leu Asp His Gly Asp Phe 580 585 590 Leu His Ile Ala Ile Gln Ile Ala
Ala Gly Met Glu Tyr Leu Ser Ser 595 600 605 His Phe Phe Val His Lys
Asp Leu Ala Ala Arg Asn Ile Leu Ile Gly 610 615 620 Glu Gln Leu His
Val Lys Ile Ser Asp Leu Gly Leu Ser Arg Glu Ile 625 630 635 640 Tyr
Ser Ala Asp Tyr Tyr Arg Val Gln Ser Lys Ser Ser Leu Pro Ile 645 650
655 Arg Trp Met Pro Pro Glu Ala Ile Met Tyr Gly Lys Phe Ser Ser Asp
660 665 670 Ser Asp Ile Trp Ser Phe Gly Val Val Leu Trp Glu Ile Phe
Ser Phe 675 680 685 Gly Leu Gln Pro Tyr Tyr Gly Phe Ser Asn Gln Glu
Val Ile Glu Met 690 695 700 Val Arg Lys Arg Gln Leu Leu Pro Cys Ser
Glu Asp Cys Pro Pro Arg 705 710 715 720 Met Tyr Ser Leu Met Thr Glu
Cys Trp Asn Glu Ile Pro Ser Arg Arg 725 730 735 Pro Arg Phe Lys Asp
Ile His Val Arg Leu Arg Ser Trp Glu Gly Leu 740 745 750 Ser Ser His
Thr Ser Ser Thr Thr Pro Ser Gly Gly Asn Ala Thr Thr 755 760 765 Gln
Thr Thr Ser Leu Ser Ala Ser Pro Val Ser Asn Leu Ser Asn Pro 770 775
780 Arg Phe Pro Asn Tyr Met Phe Pro Ser Gln Gly Ile Thr Pro Gln Gly
785 790 795 800 Gln Ile Ala Gly Phe Ile Gly Pro Ala Ile Pro Gln Asn
Gln Arg Phe 805 810 815 Ile Pro Ile Asn Gly Tyr Pro Ile Pro Pro Gly
Tyr Ala Ala Phe Pro 820 825 830 Ala Ala His Tyr Gln Pro Ala Gly Pro
Pro Arg Val Ile Gln His Cys 835 840 845 Pro Pro Pro Lys Ser Arg Ser
Pro Ser Ser Ala Arg Gly Ser Thr Ser 850 855 860 Thr Gly His Val Ala
Ser Leu Pro Ser Ser Gly Ser Asn Gln Glu Ala 865 870 875 880 Asn Val
Pro Leu Leu Pro His Met Ser Ile Pro Asn His Pro Gly Gly 885 890 895
Met Gly Ile Thr Val Phe Gly Asn Lys Ser Gln Lys Pro Tyr Lys Ile 900
905 910 Asp Ser Lys Gln Ser Ser Leu Leu Gly Asp Ser His Ile His Gly
His 915 920 925 Thr Glu Ser Met Ile Ser Ala Glu Val 930 935
1115PRTArtificial SequenceSynthetic 11Gly Gly Gly Gly Ser Gly Gly
Gly Gly Ser Gly Gly Gly Gly Ser 1 5 10 15 129PRTArtificial
SequenceSynthetic 12Arg Ser Thr Gly Ser Pro Gly Ser Gly 1 5
13227PRTHomo sapiens 13Asp Lys Thr His Thr Cys Pro Pro Cys Pro Ala
Pro Glu Leu Leu Gly 1 5 10 15 Gly Pro Ser Val Phe Leu Phe Pro Pro
Lys Pro Lys Asp Thr Leu Met 20 25 30 Ile Ser Arg Thr Pro Glu Val
Thr Cys
Val Val Val Asp Val Ser His 35 40 45 Glu Asp Pro Glu Val Lys Phe
Asn Trp Tyr Val Asp Gly Val Glu Val 50 55 60 His Asn Ala Lys Thr
Lys Pro Arg Glu Glu Gln Tyr Asn Ser Thr Tyr 65 70 75 80 Arg Val Val
Ser Val Leu Thr Val Leu His Gln Asp Trp Leu Asn Gly 85 90 95 Lys
Glu Tyr Lys Cys Lys Val Ser Asn Lys Ala Leu Pro Ala Pro Ile 100 105
110 Glu Lys Thr Ile Ser Lys Ala Lys Gly Gln Pro Arg Glu Pro Gln Val
115 120 125 Tyr Thr Leu Pro Pro Ser Arg Asp Glu Leu Thr Lys Asn Gln
Val Ser 130 135 140 Leu Thr Cys Leu Val Lys Gly Phe Tyr Pro Ser Asp
Ile Ala Val Glu 145 150 155 160 Trp Glu Ser Asn Gly Gln Pro Glu Asn
Asn Tyr Lys Thr Thr Pro Pro 165 170 175 Val Leu Asp Ser Asp Gly Ser
Phe Phe Leu Tyr Ser Lys Leu Thr Val 180 185 190 Asp Lys Ser Arg Trp
Gln Gln Gly Asn Val Phe Ser Cys Ser Val Met 195 200 205 His Glu Ala
Leu His Asn His Tyr Thr Gln Lys Ser Leu Ser Leu Ser 210 215 220 Pro
Gly Lys 225 1416PRTHomo sapiens 14Asp Lys Thr His Thr Cys Pro Pro
Cys Pro Ala Pro Glu Leu Leu Gly 1 5 10 15 15104PRTHomo sapiens
15Gly Pro Ser Val Phe Leu Phe Pro Pro Lys Pro Lys Asp Thr Leu Met 1
5 10 15 Ile Ser Arg Thr Pro Glu Val Thr Cys Val Val Val Asp Val Ser
His 20 25 30 Glu Asp Pro Glu Val Lys Phe Asn Trp Tyr Val Asp Gly
Val Glu Val 35 40 45 His Asn Ala Lys Thr Lys Pro Arg Glu Glu Gln
Tyr Asn Ser Thr Tyr 50 55 60 Arg Val Val Ser Val Leu Thr Val Leu
His Gln Asp Trp Leu Asn Gly 65 70 75 80 Lys Glu Tyr Lys Cys Lys Val
Ser Asn Lys Ala Leu Pro Ala Pro Ile 85 90 95 Glu Lys Thr Ile Ser
Lys Ala Lys 100 16107PRTHomo sapiens 16Gly Gln Pro Arg Glu Pro Gln
Val Tyr Thr Leu Pro Pro Ser Arg Asp 1 5 10 15 Glu Leu Thr Lys Asn
Gln Val Ser Leu Thr Cys Leu Val Lys Gly Phe 20 25 30 Tyr Pro Ser
Asp Ile Ala Val Glu Trp Glu Ser Asn Gly Gln Pro Glu 35 40 45 Asn
Asn Tyr Lys Thr Thr Pro Pro Val Leu Asp Ser Asp Gly Ser Phe 50 55
60 Phe Leu Tyr Ser Lys Leu Thr Val Asp Lys Ser Arg Trp Gln Gln Gly
65 70 75 80 Asn Val Phe Ser Cys Ser Val Met His Glu Ala Leu His Asn
His Tyr 85 90 95 Thr Gln Lys Ser Leu Ser Leu Ser Pro Gly Lys 100
105 1717PRTHomo sapiens 17Glu Arg Lys Cys Cys Val Glu Cys Pro Pro
Cys Pro Ala Pro Pro Val 1 5 10 15 Ala 1810PRTHomo sapiens 18Cys Pro
Pro Cys Pro Ala Pro Pro Val Ala 1 5 10 19104PRTHomo sapiens 19Gly
Pro Ser Val Phe Leu Phe Pro Pro Lys Pro Lys Asp Thr Leu Met 1 5 10
15 Ile Ser Arg Thr Pro Glu Val Thr Cys Val Val Val Asp Val Ser His
20 25 30 Glu Asp Pro Glu Val Gln Phe Asn Trp Tyr Val Asp Gly Val
Glu Val 35 40 45 His Asn Ala Lys Thr Lys Pro Arg Glu Glu Gln Phe
Asn Ser Thr Phe 50 55 60 Arg Val Val Ser Val Leu Thr Val Val His
Gln Asp Trp Leu Asn Gly 65 70 75 80 Lys Glu Tyr Lys Cys Lys Val Ser
Asn Lys Gly Leu Pro Ala Pro Ile 85 90 95 Glu Lys Thr Ile Ser Lys
Thr Lys 100 20107PRTHomo sapiens 20Gly Gln Pro Arg Glu Pro Gln Val
Tyr Thr Leu Pro Pro Ser Arg Glu 1 5 10 15 Glu Met Thr Lys Asn Gln
Val Ser Leu Thr Cys Leu Val Lys Gly Phe 20 25 30 Tyr Pro Ser Asp
Ile Ser Val Glu Trp Glu Ser Asn Gly Gln Pro Glu 35 40 45 Asn Asn
Tyr Lys Thr Thr Pro Pro Met Leu Asp Ser Asp Gly Ser Phe 50 55 60
Phe Leu Tyr Ser Lys Leu Thr Val Asp Lys Ser Arg Trp Gln Gln Gly 65
70 75 80 Asn Val Phe Ser Cys Ser Val Met His Glu Ala Leu His Asn
His Tyr 85 90 95 Thr Gln Lys Ser Leu Ser Leu Ser Pro Gly Lys 100
105 2118PRTHomo sapiens 21Glu Ser Lys Tyr Gly Pro Pro Cys Pro Ser
Cys Pro Ala Pro Glu Phe 1 5 10 15 Leu Gly 2213PRTHomo sapiens 22Pro
Pro Cys Pro Ser Cys Pro Ala Pro Glu Phe Leu Gly 1 5 10 23104PRTHomo
sapiens 23Gly Pro Ser Val Phe Leu Phe Pro Pro Lys Pro Lys Asp Thr
Leu Met 1 5 10 15 Ile Ser Arg Thr Pro Glu Val Thr Cys Val Val Val
Asp Val Ser Gln 20 25 30 Glu Asp Pro Glu Val Gln Phe Asn Trp Tyr
Val Asp Gly Val Glu Val 35 40 45 His Asn Ala Lys Thr Lys Pro Arg
Glu Glu Gln Phe Asn Ser Thr Tyr 50 55 60 Arg Val Val Ser Val Leu
Thr Val Leu His Gln Asp Trp Leu Asn Gly 65 70 75 80 Lys Glu Tyr Lys
Cys Lys Val Ser Asn Lys Gly Leu Pro Ser Ser Ile 85 90 95 Glu Lys
Thr Ile Ser Lys Ala Lys 100 24107PRTHomo sapiens 24Gly Gln Pro Arg
Glu Pro Gln Val Tyr Thr Leu Pro Pro Ser Gln Glu 1 5 10 15 Glu Met
Thr Lys Asn Gln Val Ser Leu Thr Cys Leu Val Lys Gly Phe 20 25 30
Tyr Pro Ser Asp Ile Ala Val Glu Trp Glu Ser Asn Gly Gln Pro Glu 35
40 45 Asn Asn Tyr Lys Thr Thr Pro Pro Val Leu Asp Ser Asp Gly Ser
Phe 50 55 60 Phe Leu Tyr Ser Arg Leu Thr Val Asp Lys Ser Arg Trp
Gln Glu Gly 65 70 75 80 Asn Val Phe Ser Cys Ser Val Met His Glu Ala
Leu His Asn His Tyr 85 90 95 Thr Gln Lys Ser Leu Ser Leu Ser Leu
Gly Lys 100 105 25882DNAArtificial SequenceSynthetic 25atgcacagac
ctagacgtcg tggaactcgt ccacctccac tggcactgct cgctgctctc 60ctcctggctg
cacgtggtgc tgatgcaaga tctaccggta gcccgggctc cggagacaaa
120actcacacat gcccaccgtg cccagcacct gaactcctgg ggggaccgtc
agtcttcctc 180ttccccccaa aacccaagga caccctcatg atctcccgga
cccctgaggt cacatgcgtg 240gtggtggacg tgagccacga agaccctgag
gtcaagttca actggtacgt ggacggcgtg 300gaggtgcata atgccaagac
aaagccgcgg gaggagcagt acaacagcac gtaccgtgtg 360gtcagcgtcc
tcaccgtcct gcaccaggac tggctgaatg gcaaggagta caagtgcaag
420gtctccaaca aagccctccc agcccccatc gagaaaacca tctccaaagc
caaagggcag 480ccccgagaac cacaggtgta caccctgccc ccatcccggg
atgagctgac caagaaccag 540gtcagcctga cctgcctggt caaaggcttc
tatcccagcg acatcgccgt ggagtgggag 600agcaatgggc agccggagaa
caactacaag accacgcctc ccgtgctgga ctccgacggc 660tccttcttcc
tctacagcaa gctcaccgtg gacaagagca ggtggcagca ggggaacgtc
720ttctcatgct ccgtgatgca tgaggctctg cacaaccact acacgcagaa
gtccctctcc 780ctgtctccgg gtaaaggtgg aggcggttca ggcggaggtg
gctctggcgg tggcggatcg 840cagaggccca ggctgagcca caagggcccc
atgcccttct ga 88226855DNAArtificial SequenceSynthetic 26atgcacagac
ctagacgtcg tggaactcgt ccacctccac tggcactgct cgctgctctc 60ctcctggctg
cacgtggtgc tgatgcacag aggcccaggc tgagccacaa gggccccatg
120cccttcggtg gaggcggttc aggcggaggt ggctctggcg gtggcggatc
ggacaaaact 180cacacatgcc caccgtgccc agcacctgaa ctcctggggg
gaccgtcagt cttcctcttc 240cccccaaaac ccaaggacac cctcatgatc
tcccggaccc ctgaggtcac atgcgtggtg 300gtggacgtga gccacgaaga
ccctgaggtc aagttcaact ggtacgtgga cggcgtggag 360gtgcataatg
ccaagacaaa gccgcgggag gagcagtaca acagcacgta ccgtgtggtc
420agcgtcctca ccgtcctgca ccaggactgg ctgaatggca aggagtacaa
gtgcaaggtc 480tccaacaaag ccctcccagc ccccatcgag aaaaccatct
ccaaagccaa agggcagccc 540cgagaaccac aggtgtacac cctgccccca
tcccgggatg agctgaccaa gaaccaggtc 600agcctgacct gcctggtcaa
aggcttctat cccagcgaca tcgccgtgga gtgggagagc 660aatgggcagc
cggagaacaa ctacaagacc acgcctcccg tgctggactc cgacggctcc
720ttcttcctct acagcaagct caccgtggac aagagcaggt ggcagcaggg
gaacgtcttc 780tcatgctccg tgatgcatga ggctctgcac aaccactaca
cgcagaagtc cctctccctg 840tctccgggta aatag 85527768DNAArtificial
SequenceSynthetic 27gacaaaactc acacatgccc accgtgccca gcacctgaac
tcctgggggg accgtcagtc 60ttcctcttcc ccccaaaacc caaggacacc ctcatgatct
cccggacccc tgaggtcaca 120tgcgtggtgg tggacgtgag ccacgaagac
cctgaggtca agttcaactg gtacgtggac 180ggcgtggagg tgcataatgc
caagacaaag ccgcgggagg agcagtacaa cagcacgtac 240cgtgtggtca
gcgtcctcac cgtcctgcac caggactggc tgaatggcaa ggagtacaag
300tgcaaggtct ccaacaaagc cctcccagcc cccatcgaga aaaccatctc
caaagccaaa 360gggcagcccc gagaaccaca ggtgtacacc ctgcccccat
cccgggatga gctgaccaag 420aaccaggtca gcctgacctg cctggtcaaa
ggcttctatc ccagcgacat cgccgtggag 480tgggagagca atgggcagcc
ggagaacaac tacaagacca cgcctcccgt gctggactcc 540gacggctcct
tcttcctcta cagcaagctc accgtggaca agagcaggtg gcagcagggg
600aacgtcttct catgctccgt gatgcatgag gctctgcaca accactacac
gcagaagtcc 660ctctccctgt ctccgggtaa aggtggaggc ggttcaggcg
gaggtggctc tggcggtggc 720ggatcgcaga ggcccaggct gagccacaag
ggccccatgc ccttctga 76828768DNAArtificial SequenceSynthetic
28cagaggccca ggctgagcca caagggcccc atgcccttcg gtggaggcgg ttcaggcgga
60ggtggctctg gcggtggcgg atcggacaaa actcacacat gcccaccgtg cccagcacct
120gaactcctgg ggggaccgtc agtcttcctc ttccccccaa aacccaagga
caccctcatg 180atctcccgga cccctgaggt cacatgcgtg gtggtggacg
tgagccacga agaccctgag 240gtcaagttca actggtacgt ggacggcgtg
gaggtgcata atgccaagac aaagccgcgg 300gaggagcagt acaacagcac
gtaccgtgtg gtcagcgtcc tcaccgtcct gcaccaggac 360tggctgaatg
gcaaggagta caagtgcaag gtctccaaca aagccctccc agcccccatc
420gagaaaacca tctccaaagc caaagggcag ccccgagaac cacaggtgta
caccctgccc 480ccatcccggg atgagctgac caagaaccag gtcagcctga
cctgcctggt caaaggcttc 540tatcccagcg acatcgccgt ggagtgggag
agcaatgggc agccggagaa caactacaag 600accacgcctc ccgtgctgga
ctccgacggc tccttcttcc tctacagcaa gctcaccgtg 660gacaagagca
ggtggcagca ggggaacgtc ttctcatgct ccgtgatgca tgaggctctg
720cacaaccact acacgcagaa gtccctctcc ctgtctccgg gtaaatag
7682913PRTArtificial SequenceSynthetic 29Gln Arg Pro Arg Leu Ser
His Lys Gly Pro Met Pro Ala 1 5 10 3012PRTArtificial
SequenceSynthetic 30Gln Arg Pro Arg Leu Ser His Lys Gly Pro Met Pro
1 5 10 3111PRTArtificial SequenceSynthetic 31Gln Arg Pro Arg Leu
Ser His Lys Gly Pro Met 1 5 10 3212PRTArtificial SequenceSynthetic
32Arg Pro Arg Leu Ser His Lys Gly Pro Met Pro Phe 1 5 10
3311PRTArtificial SequenceSynthetic 33Pro Arg Leu Ser His Lys Gly
Pro Met Pro Phe 1 5 10 3411PRTArtificial SequenceSynthetic 34Arg
Pro Arg Leu Ser His Lys Gly Pro Met Pro 1 5 10 3510PRTArtificial
SequenceSynthetic 35Pro Arg Leu Ser His Lys Gly Pro Met Pro 1 5 10
3610PRTArtificial SequenceSynthetic 36Arg Pro Arg Leu Ser His Lys
Gly Pro Met 1 5 10 379PRTArtificial SequenceSynthetic 37Pro Arg Leu
Ser His Lys Gly Pro Met 1 5 3818PRTArtificial SequenceSynthetic
38Gln Arg Pro Arg Leu Ser His Lys Gly Pro Met Pro Phe Gly Gly Gly 1
5 10 15 Gly Gly 39256PRTArtificial SequenceSynthetic 39Asp Lys Thr
His Thr Cys Pro Pro Cys Pro Ala Pro Glu Leu Leu Gly 1 5 10 15 Gly
Pro Ser Val Phe Leu Phe Pro Pro Lys Pro Lys Asp Thr Leu Met 20 25
30 Ile Ser Arg Thr Pro Glu Val Thr Cys Val Val Val Asp Val Ser His
35 40 45 Glu Asp Pro Glu Val Lys Phe Asn Trp Tyr Val Asp Gly Val
Glu Val 50 55 60 His Asn Ala Lys Thr Lys Pro Arg Glu Glu Gln Tyr
Asn Ser Thr Tyr 65 70 75 80 Arg Val Val Ser Val Leu Thr Val Leu His
Gln Asp Trp Leu Asn Gly 85 90 95 Lys Glu Tyr Lys Cys Lys Val Ser
Asn Lys Ala Leu Pro Ala Pro Ile 100 105 110 Glu Lys Thr Ile Ser Lys
Ala Lys Gly Gln Pro Arg Glu Pro Gln Val 115 120 125 Tyr Thr Leu Pro
Pro Ser Arg Asp Glu Leu Thr Lys Asn Gln Val Ser 130 135 140 Leu Thr
Cys Leu Val Lys Gly Phe Tyr Pro Ser Asp Ile Ala Val Glu 145 150 155
160 Trp Glu Ser Asn Gly Gln Pro Glu Asn Asn Tyr Lys Thr Thr Pro Pro
165 170 175 Val Leu Asp Ser Asp Gly Ser Phe Phe Leu Tyr Ser Lys Leu
Thr Val 180 185 190 Asp Lys Ser Arg Trp Gln Gln Gly Asn Val Phe Ser
Cys Ser Val Met 195 200 205 His Glu Ala Leu His Asn His Tyr Thr Gln
Lys Ser Leu Ser Leu Ser 210 215 220 Pro Gly Lys Gly Gly Gly Gly Ser
Gly Gly Gly Gly Ser Gly Gly Gly 225 230 235 240 Gly Ser Gln Arg Pro
Arg Leu Ser His Lys Gly Pro Met Pro Phe Arg 245 250 255
40256PRTArtificial SequenceSynthetic 40Asp Lys Thr His Thr Cys Pro
Pro Cys Pro Ala Pro Glu Leu Leu Gly 1 5 10 15 Gly Pro Ser Val Phe
Leu Phe Pro Pro Lys Pro Lys Asp Thr Leu Met 20 25 30 Ile Ser Arg
Thr Pro Glu Val Thr Cys Val Val Val Asp Val Ser His 35 40 45 Glu
Asp Pro Glu Val Lys Phe Asn Trp Tyr Val Asp Gly Val Glu Val 50 55
60 His Asn Ala Lys Thr Lys Pro Arg Glu Glu Gln Tyr Asn Ser Thr Tyr
65 70 75 80 Arg Val Val Ser Val Leu Thr Val Leu His Gln Asp Trp Leu
Asn Gly 85 90 95 Lys Glu Tyr Lys Cys Lys Val Ser Asn Lys Ala Leu
Pro Ala Pro Ile 100 105 110 Glu Lys Thr Ile Ser Lys Ala Lys Gly Gln
Pro Arg Glu Pro Gln Val 115 120 125 Tyr Thr Leu Pro Pro Ser Arg Asp
Glu Leu Thr Lys Asn Gln Val Ser 130 135 140 Leu Thr Cys Leu Val Lys
Gly Phe Tyr Pro Ser Asp Ile Ala Val Glu 145 150 155 160 Trp Glu Ser
Asn Gly Gln Pro Glu Asn Asn Tyr Lys Thr Thr Pro Pro 165 170 175 Val
Leu Asp Ser Asp Gly Ser Phe Phe Leu Tyr Ser Lys Leu Thr Val 180 185
190 Asp Lys Ser Arg Trp Gln Gln Gly Asn Val Phe Ser Cys Ser Val Met
195 200 205 His Glu Ala Leu His Asn His Tyr Thr Gln Lys Ser Leu Ser
Leu Ser 210 215 220 Pro Gly Lys Gly Gly Gly Gly Ser Gly Gly Gly Gly
Ser Gly Gly Gly 225 230 235 240 Gly Ser Gln Arg Pro Arg Leu Ser His
Lys Gly Pro Met Pro Phe Ser 245 250 255 41256PRTArtificial
SequenceSynthetic 41Asp Lys Thr His Thr Cys Pro Pro Cys Pro Ala Pro
Glu Leu Leu Gly 1 5 10 15 Gly Pro Ser Val Phe Leu Phe Pro Pro Lys
Pro Lys Asp Thr Leu Met 20 25 30 Ile Ser Arg Thr Pro Glu Val Thr
Cys Val Val Val Asp Val Ser His 35 40 45 Glu Asp Pro Glu Val Lys
Phe Asn Trp Tyr Val Asp Gly Val Glu Val 50 55 60 His Asn Ala Lys
Thr Lys Pro Arg Glu Glu Gln Tyr Asn Ser Thr Tyr 65 70 75 80 Arg Val
Val Ser Val Leu Thr Val Leu His Gln Asp Trp Leu Asn Gly 85 90 95
Lys Glu Tyr Lys Cys Lys Val Ser Asn Lys Ala Leu Pro Ala Pro Ile 100
105 110 Glu Lys Thr Ile Ser Lys Ala Lys Gly Gln Pro Arg Glu Pro Gln
Val 115 120 125 Tyr Thr Leu Pro Pro Ser Arg Asp Glu Leu Thr Lys Asn
Gln
Val Ser 130 135 140 Leu Thr Cys Leu Val Lys Gly Phe Tyr Pro Ser Asp
Ile Ala Val Glu 145 150 155 160 Trp Glu Ser Asn Gly Gln Pro Glu Asn
Asn Tyr Lys Thr Thr Pro Pro 165 170 175 Val Leu Asp Ser Asp Gly Ser
Phe Phe Leu Tyr Ser Lys Leu Thr Val 180 185 190 Asp Lys Ser Arg Trp
Gln Gln Gly Asn Val Phe Ser Cys Ser Val Met 195 200 205 His Glu Ala
Leu His Asn His Tyr Thr Gln Lys Ser Leu Ser Leu Ser 210 215 220 Pro
Gly Lys Gly Gly Gly Gly Ser Gly Gly Gly Gly Ser Gly Gly Gly 225 230
235 240 Gly Ser Gln Arg Pro Arg Leu Ser His Lys Gly Pro Met Pro Phe
His 245 250 255 4214PRTArtificial SequenceSynthetic 42Gln Arg Pro
Arg Leu Ser His Lys Gly Pro Met Pro Phe Arg 1 5 10
4314PRTArtificial SequenceSynthetic 43Gln Arg Pro Arg Leu Ser His
Lys Gly Pro Met Pro Phe Ser 1 5 10 4414PRTArtificial
SequenceSynthetic 44Gln Arg Pro Arg Leu Ser His Lys Gly Pro Met Pro
Phe His 1 5 10
* * * * *
References