U.S. patent application number 12/948199 was filed with the patent office on 2011-03-17 for lacritin-syndecan interactions.
This patent application is currently assigned to UNIVERSITY OF VIRGINIA PATENT FOUNDATION. Invention is credited to Gordon W. Laurie, Peisong Ma.
Application Number | 20110065189 12/948199 |
Document ID | / |
Family ID | 43730963 |
Filed Date | 2011-03-17 |
United States Patent
Application |
20110065189 |
Kind Code |
A1 |
Laurie; Gordon W. ; et
al. |
March 17, 2011 |
Lacritin-Syndecan Interactions
Abstract
The present invention relates to methods and compositions useful
for the regulation of lacritin, syndecan, and lacritin-syndecan
interactions and the signaling pathway downstream of
lacritin-syndecan interactions. The invention also relates to
regulating lacritin-syndecan interaction to regulate ocular cell
survival in response to an insult or injury, in protecting against
ocular inflammation, and in promoting ocular wound repair.
Inventors: |
Laurie; Gordon W.;
(Charlottesville, VA) ; Ma; Peisong; (Voorhees,
NJ) |
Assignee: |
UNIVERSITY OF VIRGINIA PATENT
FOUNDATION
Charlottesville
VA
|
Family ID: |
43730963 |
Appl. No.: |
12/948199 |
Filed: |
November 17, 2010 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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12212517 |
Sep 17, 2008 |
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12948199 |
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60994090 |
Sep 17, 2007 |
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Current U.S.
Class: |
435/375 |
Current CPC
Class: |
A61K 38/47 20130101 |
Class at
Publication: |
435/375 |
International
Class: |
C12N 5/02 20060101
C12N005/02 |
Goverment Interests
US GOVERNMENT RIGHTS
[0003] This invention was made with United States Government
support under Grant No. RO1 EY13143, awarded by National Institutes
of Health. The United States Government may have certain rights in
the invention.
Claims
1.-7. (canceled)
8. A method to enhance lacritin-syndecan-1 interactions in a cell
comprising contacting a cell with heparanase.
9. The method of claim 8, wherein the heparanase modifies
syndecan.
10. The method of claim 9, wherein the modification is the removal
of a heparin sulfate moiety.
11. The method of claim 8, wherein the heparanase deglycanates
syndecan.
12-14. (canceled)
Description
RELATED APPLICATIONS
[0001] This application claims priority from U.S. Provisional
Application Ser. No. 60/994,090, filed Sep. 17, 2007, titled
Lacritin-Syndecan Interactions, which application is herein
incorporated in its entirety by reference.
[0002] This application is also related to U.S. Pat. No. 7,320,870;
U.S. application Ser. No. 10/468,372 which published as 20040081984
on Apr. 29, 2004; U.S. application Ser. No. 11/596,506 which
published as 20070207522 on Sep. 6, 2007 and WO 2008/033477, which
patent, applications and publications are herein incorporated in
their entirety by referenced.
BACKGROUND
[0004] Cell surface proteoglycans are key players in epithelial
morphogenesis. They form gradients that immobilize mitogens in
proximity to signaling receptors (Wang and Laurie, 2004; Hacker et
al., 2005; Radtke and Clevers, 2005), contribute to cellular
adhesion by ligating the extracellular matrix (ECM) and at least in
one case participate in integrin coupling (Beauvais et al., 2004;
McQuade et al., 2006). Cell surface proteoglycans consist of a core
protein and associated glycosaminoglycan chains, mainly heparan
sulfate (HS). Current dogma states that mitogen, cytokine and ECM
binding is largely the domain of the anionic HS chains (Couchman
2003; Hacker et al., 2005). HS chains are generated by a complement
of Golgi polymerases, epimerase, and sulphotransferases during
post-translational modification. Each is thought to vary in
relative activity by cell or tissue type (Perrimon and Bernfield,
2000). Thus within a given epithelium or endothelium, a
structurally similar HS chain can be attached to genetically
distinct core protein (Zako et al., 2003).
[0005] New work has shed light on how HS proteoglycan specificity
is generated in development and disease. Most involve extracellular
enzymes that affect cell surface HS proteoglycans in unexpected
ways. Removal of certain HS 6-O-sulfates by endo-6-O-sulfatases
Sulf1 and Sulf2 disrupts the binding of the BMP inhibitor Noggin,
leading to its dispersal and establishment of BMP signaling
(Viviano et al., 2004). In contrast, this same HS modification
diminishes FGF binding and assembly with its signaling receptor
(Dai et al., 2005). In another extracellular modification
mechanism, HS cleavage by heparanase generates soluble fragments of
HS that form complexes of FGF-HS and trigger cellular
proliferation, migration, and angiogenesis (Kato et al., 1998). In
another mechanism, matrix metalloproteinase-7-dependent shedding of
the entire syndecan ectodomain promotes cancer-associated
upregulation of glypican-1 and tumor growth (Ding et al.,
2005).
[0006] In addition to its HS-dependent signaling mechanisms, recent
work has shown that the syndecan core proteins themselves
participate as cell surface receptors. Their extracellular protein
domains regulate the activation of integrins (Beauvais et al. 2003;
Beauvais et al., 2004; McQuade et al. 2006), bind growth factors,
including Wnt, midkine and pleitrophin (Capurro et al, 2005; Deepa
et al. 2004), and disrupt carcinoma activity when added as
recombinant competitors, presumably by disrupting their assembly
with other signaling receptors at the cell surface.
[0007] There is a long felt need in the art for methods and
compositions to identify and regulate the signaling pathways of
lacritin and syndecan. The present invention satisfies these
needs.
SUMMARY OF THE INVENTION
[0008] Here we report on a novel mechanism of syndecan-1 (SDC1)
signaling that relies on a direct binding interaction of the
extracellular core protein domain of the syndecan and modification
of the proteoglycan by HS-modifying enzyme. The mechanism involves
the partially characterized prosecretory mitogen lacritin
discovered as a consequence of a search for epithelial
differentiation factors (Sanghi et al., 2001). Lacritin is a small
(12.3 kDa) epithelial-selective human glycoprotein secreted in tear
protein (accession Q9GZZ8). Lacritin signals to STIM1, mTOR and
NFATC1 via rapid PKC.alpha. dephosphorylation and PLD activation
(Wang et al., 2006) to potentially regulate differentiation,
renewal and secretion by the non-germative exocrine epithelia that
it preferentially targets. With the exception of pancreatic
.beta.-cells (Dor et al., 2004), mechanisms of non-germative
epithelial differentiation and renewal are poorly understood.
Lacritin deletion analysis identified a C-terminal mitogenic domain
with amphipathic alpha-helical structure (Wang et al., 2006) common
to many ligand-receptor or ligand-ligand binding sites (Barden et
al, 1997; Siemeister et al., 1998). We report here that lacritin's
C-terminus targets the SDC1 core protein as a prerequisite for
mitogenesis. A second and novel prerequisite is prior modification
or removal of HS from the syndecan by heparanase-1. We postulate
that the localized action of heparanase converts a widely expressed
cell surface proteoglycan into a localized lacritin-binding protein
that is required for mitogenic signaling.
[0009] The present invention is based on the discovery that
lacritin interacts with syndecan, as well as novel regulation of
syndecan. The present invention is directed to the regulation of
lacritin-syndecan interactions and the associated signal
transduction pathway and events and processes regulated by this
pathway. In one aspect, regulation of the pathway is useful to
promote ocular cell survival, and more particularly to promote
ocular cell survival in the presence of an environmental insult.
The invention is also directed to the use of lacritin to prevent
and treat corneal infections and inflammation. The invention is
further directed to the use of lacritin to promote corneal wound
repair following environmental insult or surgical procedures of the
cornea. The invention is also directed to the use of lacritin as a
mitogen for only specific epithelial cells.
[0010] In one aspect, the invention encompasses a composition for
treating or preventing a disease, disorder, or condition which is
regulated or effected by lacritin via a lacritin-syndecan
interaction and signaling pathway as described herein. In one
aspect, the signaling pathways are PKC-.alpha.-dependent NFAT and
mTOR pathways. In one aspect, the compounds comprise siRNA.
[0011] Lacritin is a selective mitogen for only certain epithelial
cells. In one embodiment, the invention provides a method of
inducing proliferation of epithelial cells which are sensitive to
induction of proliferation by lacritin and fragments, derivatives,
and homologs thereof.
[0012] In one aspect, proliferation can be inhibited or blocked
using methods to inhibit lacritin, to inhibit lacritin-syndecan
interaction, and by inhibiting the downstream signaling pathway
induced by lacritin-syndecan interactions (for example, with
siRNA).
[0013] In one aspect, proliferation can be stimulated by
stimulating or enhancing lacritin, lacritin-syndecan interaction,
syndecan modification, and by stimulating the downstream signaling
pathway induced by lacritin-syndecan interactions.
[0014] In one embodiment, the present invention provides methods
and compositions for regulating or modifying syndecan to modulate
its interaction and binding with lacritin. In one aspect, the
invention provides methods and compositions for heparanase
modification of syndecan. In one aspect, the entire heparan sulfate
moiety is removed. In another aspect, the invention provides
methods and compositions for deglycanating syndecan.
[0015] One aspect provides a fusion protein comprising syndecan-1
and lacritin. In one embodiment only the N-terminal portion of
syndecan-1 is present in a fusion protein with lacritin, for
example, amino acids 1-51 of syndecan (the fusion protein is
prepared by methods available to those of skill in the art
(including recombinant techniques), as an example, the preparation
of a fusion protein is outlined in FIG. 16). Thus, heparanase or
other factors would not be needed for the interaction of lacritin
and syndecan. This fusion protein can be used in any of the methods
described herein including epithelial proliferation, protection
against inflammation and aid in wound healing after an injury or an
insult to the eye (e.g., laser eye surgery including lasik surgery
and photorefractive keratectomy (PRK)) or in preventing injury or
insult to the eye (e.g., prior to eye surgery).
[0016] In one embodiment, methods and compositions useful for
regulating heparanase are encompassed within the invention.
[0017] In one embodiment, the present invention provides methods
and compositions for targeting the binding/interaction regions of
lacritin and syndecan as described herein. In one aspect, the
domain on lacritin is at about amino acid residues 100 and 109.
[0018] In another embodiment, the invention provides a method of
treating or preventing diseases, disorders, or conditions in a
subject in need thereof by methods and compositions encompassed
within the present invention.
[0019] The invention further provides a kit for administering the
compositions of the invention.
[0020] Various aspects and embodiments of the invention are
described in further detail below.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] FIG. 1. Lacritin affinity purification of cell surface SDC1.
Detergent lysates of surface biotinylated HSG cells were incubated
overnight in detergent and physiological salt with intein-chitin
columns either lacking (A) or containing (B) lacritin. After
extensive washing in the same buffer, the columns were eluted with
1 M NaCl and eluted proteins were identified by blotting with
streptavidin-peroxidase. A predominant 190 kDa biotinylated protein
eluting from the lacritin column was identified by mass
spectrometry as human SDC1.
[0022] FIG. 2. Lacritin binding to SDC1 is independent of complete
HS/CS glycosaminoglycans. (A) Lacritin affinity precipitation of
human SDC1 multimers stably expressed by HEK293T cells.
Lacritin-intein beads were incubated with cell lysates, washed
extensively, and treated with heparitinase I/chondroitinase ABC.
Pellet (P) and supernatant (S) from the centrifuged digest were
then blotted with mAb B-B4 for SDC1 core protein. (B)
Lacritin-intein, lacritin-GST, FGF2-GST, intein and GST beads were
incubated with lysates from the same HEK293T cells stably
expressing human SDC1. Precipitates were washed, treated,
centrifuged and blotted identically as above. (C) Lacritin-intein
and FGF2-GST beads were incubated with lysate of HEK293T cells
stably expressing human SDC2 or lysate of another HEK293T cell line
stably expressing human SDC4. Beads were washed, treated and
centrifuged identically as above. Blots were detected with
anti-SDC2 mAb L-18 or anti-SDC4 mAb N-19 respectively. (A) shows
both 190 and 80 kDa bands. (B) and (C), and all subsequent figures
show the 80 kDa band which is more predominant in HEK293T
transfectants.
[0023] FIG. 3. Lacritin's C-terminus binds SDC1. (A) Schematic
diagram of lacritin with dotted lines indicating N- and C-terminal
truncations. All lacritin truncations were expressed as intein
fusion proteins for affinity precipitation. Asterisk indicates
mitogenic domain (Wang et al, submitted), and boxes represent
PSIPRED-predicted alpha helices. (B) Lacritin-, C-5-, C-10-, C-15-,
C-25- and C-59-intein beads were incubated with lysates from
HEK293T cells stably expressing human SDC1. Beads were washed and
treated with heparitinase I/chondroitinase ABC. The digests were
centrifuged, and pellets (P) and supernatants (S) blotted with mAb
B-B4 for SDC1 core protein, all as in FIG. 2. (C) Incubation of
lacritin-, N-15- and N-24-intein beads with the same human SDC1
lysates was followed with identical washing, heparitinase
I/chondroitinase ABC digestion, centrifugation and B-B4 mAb
blotting. Lys, lysate.
[0024] FIG. 4. Lacritin-SDC1 binding is inhibited by soluble hS1ED,
lacritin and N-24, but not by C-25, C-59, HS, CS, SDC2 or SDC4. (A)
Top row, lacritin-intein beads were incubated with human SDC1
lysates from stably expressing HEK293T cells in the presence of
increasing amounts of soluble HS (70-700 .mu.g), HS (700 .mu.g)
plus CS (700 .mu.g), lacritin (14-700 .mu.g) or no inhibitor (-).
Quantity of soluble inhibitor was calibrated relative to the
approximately 7-8 .mu.g of human SDC1 elutable from lacritin-intein
beads with 1 M NaCl. After incubation, beads were washed
extensively and treated with heparitinase I/chondroitinase ABC. The
digests were centrifuged, and pellets blotted with mAb B-B4 for
SDC1 core protein, as in FIG. 2. Bottom row, lacritin-intein beads
were incubated with human SDC1 lysates in the presence of soluble
N-24, C-25, C-59 (14 .mu.g of each), increasing amounts of
bacterially expressed human SDC1 ectodomain (hS1ED; 35-700 n), or
with HEK293T cell-expressed native SDC2 or native SDC4 (70 .mu.g of
each). Beads were washed and treated identically as above. (B)
Quantification of inhibition binding.
[0025] FIG. 5. SDC1 is required for lacritin-dependent mitogenesis
and COX2 expression. (A) Proliferation assay in which HSG cells
were grown for 24 h in serum-free media containing 10 nM lacritin,
10 nM C-25 lacritin or FBS in the absence or presence of increasing
amounts of soluble hS1ED. (B) Identically performed proliferation
assay in which HSG cells were treated with 10 nM lacritin or FBS 48
h after being mock transfected, or transfected with 10 nM of
Ambion's negative control siRNA #1 (neg), 1-100 nM SDC1 siRNA, or
10 nM SDC2 siRNA. (C) Above, RT-PCR and Western blotting of mock vs
SDC1 siRNA (10 nM)-treated cells. RT-PCR is for SDC1 and SDC2
mRNAs. Blotting is with mAb B-B4 for SDC1 core protein, or with
anti-GAPDH. Below, RT-PCR for SDC2 mRNA in mock transfected cells
or cells transfected with 10 nM SCD2 siRNA. (D) RT-PCR of COX2
expression by HSG cells without (-) or with (+) 10 nM lacritin
stimulation. 48 h earlier the cells were mock transfected or
transfected with 10 nM SDC1, 10 nM SDC2 or 1 nM heparanase-1
(HPSE-1) siRNAs. At bottom is GAPDH expression.
[0026] FIG. 6. Lacritin and FGF2 bind different forms of cell
surface SDC1. (A) Sequential affinity precipitation assays. Lanes
1-3, lysate from human SDC1 stably expressing HEK293T cells was
sequentially incubated with three rounds of fresh FGF2-GST beads.
Half of the final depleted lysate was then incubated with
lacritin-intein beads (lane 4) and the other half was methanol
precipitated (lane 9). Similarly in lanes 5-7, a different aliquot
of lysate from the same cells was sequentially incubated with three
rounds of fresh lacritin-intein beads. Half of the final depleted
lysate was then incubated with FGF2-GST beads (lane 8) and the
other half was methanol precipitated (lane 10). Beads were washed
and treated with heparitinase I/chondroitinase ABC. The digests
were centrifuged, and pellets (P) and supernatants (S) blotted with
mAb B-B4 for SDC1 core protein. Respectively shown are digest
supernatants (lanes 1-3 and 8) and pellets (lanes 4-7) as per
heparitinase release of FGF2-bound or resistance of lacritin-bound
SDC1. (B) HEK293T cells stably expressing human SDC1 were either
lysed as usual, or first briefly trypsinized (<5 min; 0.05%)
then treated with serum to inactivate trypsin, washed and lysed.
Both lysates were incubated with lacritin-intein beads. Beads were
washed, treated with heparitinase I/chondroitinase ABC. The digests
were centrifuged, and pellets (P) and supernatants (S) blotted with
mAb B-B4 for SDC1 core protein. (C) Lysates from HEK293T cells
stably expressing human SDC1 were incubated with lacritin-intein
beads. Beads were washed and either left untreated (lane 1) or
treated with heparitinase I/chondroitinase ABC (lanes 2, 3). The
treated sample was centrifuged. Pellet (P; lane 2), supernatant (S;
lane 3), untreated precipitate (lane 1), starting lysate (lane 4)
and lacritin-intein solubilized from fresh lacritin-intein beads
were blotted with mAb 3G10 for desaturated uronates in SDC1.
[0027] FIG. 7. Bacterial heparitinase digestion exposes
FGF2-bindable SDC1 to lacritin-binding via a domain in SDC1's
N-terminal 50 amino acids. (A) Human SDC1, SDC2 and SDC4 from
stably expressing HEK293T cells were individually purified on
FGF2-GST, eluted (0.5 and 1 M NaCl, respectively lanes 1 and 2
[SDC1], lanes 3 and 4 [SDC2], lanes 5 and 6 [SDC4]), then treated
with heparitinase I/chondroitinase ABC (2 h) and incubated with
lacritin-intein beads. Blotting is respectively with mAb B-B4 for
SDC1, polyclonal antibody L-18 for SDC2 or polyclonal N-19 for
SDC4--all core protein specific. (B) Schematic diagram of human
SDC1 with the dotted line indicating truncation sites in the
ectodomain forming deletion constructs: `del 1-51`, `del 51-252`,
and `del 51-310`. Boxes represent PSIPRED-predicted alpha helices.
Wavy lines represent HS and CS. TM, transmembrane domain. (C)
Comparative incubation of FGF2-GST and lacritin-intein beads with
human SDC1 or human SDC1 `del 1-51` lysates from stably expressing
HEK293T cells. After incubation, beads were washed extensively,
then either treated with heparitinase I/chondroitinase ABC (+) or
left untreated (-). Beads were centrifuged, and pellets (P) and
supernatants (S) blotted with mAb B-B4 for SDC1 core protein.
Lysate from HEK293T cells stably expressing SDC1 `del 1-51` is
blotted in lanes 6, 7. (D) Comparative incubation of
lacritin-intein beads with human SDC1 `del 51-252`, `del 1-51` or
`del 51-310` lysates from stably or transiently expressing HEK293T
cells. `pcDNA` is lysate from cells transfected with vector only.
After incubation, beads were washed extensively, then treated with
heparitinase I/chondroitinase ABC. Beads were centrifuged, and
pellets blotted with mAb 3G10 for desaturated uronates in SDC1.
[0028] FIG. 8. Heparanase is expressed by HEK293T and HSG cells and
is required for lacritin-dependent mitogenesis. (A) Lysates of HSG
cells (lane 1) and HEK293T cells stably expressing human SDC1
(lanes 2), versus 2 M NaCl eluant of each after incubation with
HiTrap heparin affinity columns (respectively lanes 3, 4). Blotting
is with polyclonal anti-human heparanase-1 (HPSE1) antibody. (B)
Lysates from HSG cells that had been mock transfected, or
transfected with 1 nM heparanase-1 siRNA. Blotting is with
polyclonal anti-human HPSE1 or anti-tubulin antibodies. (C)
Proliferation assay in which HSG cells were treated with 10 nM
lacritin or 1 nM EGF 48 h after being mock transfected, or
transfected with 10 nM of Ambion's negative control siRNA #1 (neg),
1-100 nM HPSE1 siRNA, or 1 nM HPSE2 siRNA. Some HPSE1 siRNA cells
were lacritin treated for 24 h in the presence of 1 .mu.g of
heparanase-enriched eluant (A, above) from HEK293T cells stably
expressing SDC1 (`1 nM+HPSE`) or 0.0001 U of bacterial
heparitinase. (D) Sepharose CL-6B gel filtration chromatography of
HS from lacritin and FGF2 affinity enriched SDC1 isolated from
normal or HPSE1 depleted HSG cells. Lysates from cells labeled with
50 .mu.Ci/ml Na.sub.2.sup.35SO.sub.4 in DMEM for 48 h were affinity
precipitated with FGF2-GST or lacritin-intein. Equal microgram
amounts of SDC1 bound to beads was digested with chondroitin ABC
lyase to remove CS, eluted with 2 M NaCl and then subjected to
NaBH4 eliminative cleavage. Released HS was neutralized by drop
wise addition of 1 M HCl and then subjected to Sepharose CL-6B gel
filtration chromatography to compare relative size of HS chains.
V0, void volume (dextran blue); Vt, total volume (sodium
dichromate).
[0029] FIG. 9. Proposed model of epithelial cell targeting by
lacritin. Deglycanated core protein of SDC1 targets the epithelial
selective prosecretory mitogen lacritin. (i) Binding requires prior
partial or complete removal of HS chains by endogenous HPSE1. (ii)
Binding is mutually specified by lacritin's C-terminal mitogenic
domain and SDC1's N-terminus.
[0030] FIG. 10. Size heterogeneity of native SDC1 is attributable
to its HS and CS chains. Lysates of HSG and HEK293T cells stably
expressing human SDC1 either without (-) or with (+) heparitinase
I/chondroitinase ABC digestion. Blotting is with mAb B-B4 for SDC1
core protein.
[0031] FIG. 11. Heparanase and heparitinase alone are not mitogenic
for HSG cells. Mitogenic assay in which HPSE1-depleted HSG cells
were incubated for 24 h with 1 .mu.g of heparanase (enriched
fraction from HEK293T) or with 0.0001 U of bacterial heparitinase
in the presence of 3H-thymidine. FBS serves as a positive
control.
[0032] FIG. 12. A, Heparanase-dependent signaling. Removal of
heparan sulfate chain(s) from syndecan-1 unblocks a lacritin
binding site on an N-terminal domain of the core protein of
syndecan-1 (Ma et al, '06). Syndecan-1 binding may improve
lacritin's affinity for its G-protein coupled receptor (possibly
ADRA2C; Ma and Laurie, unpublished), thereby activating calcineurin
and mTOR signaling towards ocular surface wetting and renewal. B,
Equal protein loads of human tears from normal and dry eye patients
blotted for heparanase. C, Detection of heparanase released into
the medium of HSG (human salivary ductal) cells after stimulation
for 2 hr with 10 .mu.M ATP, 10 .mu.M UTP or 10 nM lacritin. HCE-T
cells are also responsive (not shown).
[0033] FIG. 13. Competition binding assay of lacritin, C-25 and
N-24 for cloned GPCRs against radiolabeled agonist. N-24 inhibits
64% of 125I-iodoclonidine binding to the alpha-2C-adrenergic
receptor (`Alpha2C` or `ADRA2C`). Significant inhibition is
considered >50% (red dashed line). Determinations were repeated
four times. Assay descriptions are available to an art worker and
at http://pdsp.med.unc.edu/. The lacritin receptor is expected to
be a GPCR because lacritin signaling is pertussis toxin sensitive
(Wang et al, '06). ADRA2C couples to pertussis toxin sensitive
G-proteins.
[0034] FIG. 14. LEFT, Lacritin-dependent mitogenesis by mock or
lamin siRNA (negative control; `neg`) transfected cells contrasts
with the full or partial inhibitory effect of transfecting with
ADRA2C siRNA. D1-4 pool is most effective, followed by D1-3, D3 and
D2 (asterisks). D1 and D4 have minimal effect. Cells were
transfected with 10 nM pooled and individual siRNAs as described
for PKC.quadrature. in FIG. 4 of Wang et al ('06). RIGHT, RT-PCR of
ADRA2C at 0, 24 and 48 hrs after siRNA transfection with 10 nM
D1-4.
[0035] FIG. 15. LEFT, new N-terminal lacritin deletions (N-24
previously tested) with full length lacritin and negative control
C-25. A signaling receptor binding site (`GPCR?`) is hypothetically
suggested by loss of activity with removal of six N-amino acids
(KSIVEK) from N-65. Black box indicates region of syndecan-1 (SDC1)
binding. RIGHT, proliferation of subconfluent HCE-T cells treated
with 10 nM of each deletion construct in serum-free medium (Wang
and Laurie, unpublished). EGF serves as a positive control.
Proliferation was determined by 3H-thymidine uptake (Wang et al,
'06; Ma et al, '06). Absolute fold-increase values between FIGS. 14
and 15 are not comparable because lacritin preps differ.
[0036] FIG. 15. An example of a preparation of a lacritin/syndecan
fusion protein.
DETAILED DESCRIPTION OF THE INVENTION
Abbreviations and Acronyms
[0037] FACS means fluorescence activated cell sorter
[0038] HCE means human corneal epithelial
[0039] HS means heparan sulfate
[0040] HSG means human salivary gland
[0041] IRB means institutional review board
[0042] SDC1 means syndecan-1
DEFINITIONS
[0043] In describing and claiming the invention, the following
terminology will be used in accordance with the definitions set
forth below.
[0044] The articles "a" and "an" are used herein to refer to one or
to more than one (i.e., to at least one) of the grammatical object
of the article. By way of example, "an element" means one element
or more than one element.
[0045] As used herein, amino acids are represented by the full name
thereof, by the three letter code corresponding thereto, or by the
one-letter code corresponding thereto, as indicated in the
following table:
TABLE-US-00001 Full Name Three-Letter Code One-Letter Code Aspartic
Acid Asp D Glutamic Acid Glu E Lysine Lys K Arginine Arg R
Histidine His H Tyrosine Tyr Y Cysteine Cys C Asparagine Asn N
Glutamine Gln Q Serine Ser S Threonine Thr T Glycine Gly G Alanine
Ala A Valine Val V Leucine Leu L Isoleucine Ile I Methionine Met M
Proline Pro P Phenylalanine Phe F Tryptophan Trp W
[0046] The expression "amino acid" as used herein is meant to
include both natural and synthetic amino acids, and both D and L
amino acids. "Standard amino acid" means any of the twenty standard
L-amino acids commonly found in naturally occurring peptides.
"Nonstandard amino acid residue" means any amino acid, other than
the standard amino acids, regardless of whether it is prepared
synthetically or derived from a natural source. As used herein,
"synthetic amino acid" also encompasses chemically modified amino
acids, including but not limited to salts, amino acid derivatives
(such as amides), and substitutions. Amino acids contained within
the peptides of the present invention, and particularly at the
carboxy- or amino-terminus, can be modified by methylation,
amidation, acetylation or substitution with other chemical groups
which can change the peptide's circulating half-life without
adversely affecting their activity. Additionally, a disulfide
linkage may be present or absent in the peptides of the
invention.
[0047] The term "amino acid" is used interchangeably with "amino
acid residue," and may refer to a free amino acid and to an amino
acid residue of a peptide. It will be apparent from the context in
which the term is used whether it refers to a free amino acid or a
residue of a peptide.
[0048] Amino acids have the following general structure:
##STR00001##
[0049] Amino acids may be classified into seven groups on the basis
of the side chain R: (1) aliphatic side chains, (2) side chains
containing a hydroxylic (OH) group, (3) side chains containing
sulfur atoms, (4) side chains containing an acidic or amide group,
(5) side chains containing a basic group, (6) side chains
containing an aromatic ring, and (7) proline, an imino acid in
which the side chain is fused to the amino group.
[0050] The nomenclature used to describe the peptide compounds of
the present invention follows the conventional practice wherein the
amino group is presented to the left and the carboxy group to the
right of each amino acid residue. In the formulae representing
selected specific embodiments of the present invention, the amino-
and carboxy-terminal groups, although not specifically shown, will
be understood to be in the form they would assume at physiologic pH
values, unless otherwise specified.
[0051] The term "basic" or "positively charged" amino acid as used
herein, refers to amino acids in which the R groups have a net
positive charge at pH 7.0, and include, but are not limited to, the
standard amino acids lysine, arginine, and histidine.
[0052] The term "antibody," as used herein, refers to an
immunoglobulin molecule which is able to specifically bind to a
specific epitope on an antigen. Antibodies can be intact
immunoglobulins derived from natural sources or from recombinant
sources and can be immunoreactive portions of intact
immunoglobulins. Antibodies are typically tetramers of
immunoglobulin molecules. The antibodies in the present invention
may exist in a variety of forms including, for example, polyclonal
antibodies, monoclonal antibodies, Fv, Fab and F(ab).sub.2, as well
as single chain antibodies and humanized antibodies.
[0053] "Antimicrobial agent," as used herein, refers to any
compound which impedes the growth of any microbes, or kills such
microbes.
[0054] As used herein, the term "antisense oligonucleotide" or
antisense nucleic acid means a nucleic acid polymer, at least a
portion of which is complementary to a nucleic acid which is
present in a normal cell or in an affected cell. "Antisense" refers
particularly to the nucleic acid sequence of the non-coding strand
of a double stranded DNA molecule encoding a protein, or to a
sequence which is substantially homologous to the non-coding
strand. As defined herein, an antisense sequence is complementary
to the sequence of a double stranded DNA molecule encoding a
protein. It is not necessary that the antisense sequence be
complementary solely to the coding portion of the coding strand of
the DNA molecule. The antisense sequence may be complementary to
regulatory sequences specified on the coding strand of a DNA
molecule encoding a protein, which regulatory sequences control
expression of the coding sequences. The antisense oligonucleotides
of the invention include, but are not limited to, phosphorothioate
oligonucleotides and other modifications of oligonucleotides.
[0055] As used herein, the terms "complementary" or
"complementarity" are used in reference to polynucleotides (i.e., a
sequence of nucleotides) related by the base-pairing rules. For
example, for the sequence "A-G-T," is complementary to the sequence
"T-C-A."
[0056] The terms "detect" and "identify" are used interchangeably
herein.
[0057] As used herein, a "detectable marker" or a "reporter
molecule" is an atom or a molecule that permits the specific
detection of a compound comprising the marker in the presence of
similar compounds without a marker. Detectable markers or reporter
molecules include, e.g., radioactive isotopes, antigenic
determinants, enzymes, nucleic acids available for hybridization,
chromophores, fluorophores, chemiluminescent molecules,
electrochemically detectable molecules, and molecules that provide
for altered fluorescence polarization or altered light
scattering.
[0058] An "enhancer" is a DNA regulatory element that can increase
the efficiency of transcription, regardless of the distance or
orientation of the enhancer relative to the start site of
transcription.
[0059] As used herein, the phrase "enhancing survival" refers to
decreasing the amount of death, or the rate of death, in a cell
population. Enhancing survival can be due to preventing cell death
alone (e.g., cell death in conjunction with apoptosis), or
decreasing the rate of cell death. The decrease in cell death can
also result from indirect effects such as inducing proliferation of
some cells, such indirect effect effectively replenishing at least
some or all of a population of cells as they die. Enhancing
survival of cells can also be accomplished by a combination of
inducing proliferation and decreasing cell death, or the rate of
cell death. "Promoting survival" and "enhancing survivability" are
used interchangeably with "enhancing survival" herein.
[0060] A "fragment" or "segment" is a portion of an amino acid
sequence, comprising at least one amino acid, or a portion of a
nucleic acid sequence comprising at least one nucleotide. The terms
"fragment" and "segment" are used interchangeably herein. A
fragment of a lacritin peptide which is used herein as part of a
composition for use in a treatment or to elicit a lacritin effect,
is presumed to be a biologically active fragment for the response
to be elicited.
[0061] As used herein, a "functional" biological molecule is a
biological molecule in a form in which it exhibits a property or
activity by which it is characterized. A functional enzyme, for
example, is one which exhibits the characteristic catalytic
activity by which the enzyme is characterized.
[0062] As used herein, a "gene" refers to the nucleic acid coding
sequence as well as the regulatory elements necessary for the DNA
sequence to be transcribed into messenger RNA (mRNA) and then
translated into a sequence of amino acids characteristic of a
specific polypeptide.
[0063] "Homologous" as used herein, refers to the subunit sequence
similarity between two polymeric molecules, e.g., between two
nucleic acid molecules, e.g., two DNA molecules or two RNA
molecules, or between two polypeptide molecules. When a subunit
position in both of the two molecules is occupied by the same
monomeric subunit, e.g., if a position in each of two DNA molecules
is occupied by adenine, then they are homologous at that position.
The homology between two sequences is a direct function of the
number of matching or homologous positions, e.g., if half (e.g.,
five positions in a polymer ten subunits in length) of the
positions in two compound sequences are homologous then the two
sequences are 50% homologous, if 90% of the positions, e.g., 9 of
10, are matched or homologous, the two sequences share 90%
homology. By way of example, the DNA sequences 3'ATTGCC5' and
3'TATGGC share 50% homology.
[0064] As used herein, "homology" is used synonymously with
"identity."
[0065] The determination of percent identity between two nucleotide
or amino acid sequences can be accomplished using a mathematical
algorithm. For example, a mathematical algorithm useful for
comparing two sequences is the algorithm of Karlin and Altschul
(1990, Proc. Natl. Acad. Sci. USA 87:2264-2268), modified as in
Karlin and Altschul (1993, Proc. Natl. Acad. Sci. USA
90:5873-5877). This algorithm is incorporated into the NBLAST
and)(BLAST programs of Altschul, et al. (1990, J. Mol. Biol.
215:403-410), and can be accessed, for example at the National
Center for Biotechnology Information (NCBI) world wide web site.
BLAST nucleotide searches can be performed with the NBLAST program
(designated "blastn" at the NCBI web site), using the following
parameters: gap penalty=5; gap extension penalty=2; mismatch
penalty=3; match reward=1; expectation value 10.0; and word size=11
to obtain nucleotide sequences homologous to a nucleic acid
described herein. BLAST protein searches can be performed with the
XBLAST program (designated "blastn" at the NCBI web site) or the
NCBI "blastp" program, using the following parameters: expectation
value 10.0, BLOSUM62 scoring matrix to obtain amino acid sequences
homologous to a protein molecule described herein. To obtain gapped
alignments for comparison purposes, Gapped BLAST can be utilized as
described in Altschul et al. (1997, Nucleic Acids Res.
25:3389-3402). Alternatively, PSI-Blast or PHI-Blast can be used to
perform an iterated search which detects distant relationships
between molecules (Id.) and relationships between molecules which
share a common pattern. When utilizing BLAST, Gapped BLAST,
PSI-Blast, and PHI-Blast programs, the default parameters of the
respective programs (e.g., XBLAST and NBLAST) can be used.
[0066] The percent identity between two sequences can be determined
using techniques similar to those described above, with or without
allowing gaps. In calculating percent identity, typically exact
matches are counted.
[0067] As used herein, the term "insult" refers to contact with a
substance or environmental change that results in an alteration of
normal cellular metabolism in a cell or population of cells.
Environmental insults may include, but are not limited to,
chemicals, environmental pollutants, heavy metals, viral or
bacterial infections, changes in temperature, changes in pH, as
well as agents producing oxidative damage, DNA damage, or
pathogenesis. The term "insult" is used interchangeably with
"environmental insult" herein.
[0068] An "isolated nucleic acid" refers to a nucleic acid segment
or fragment which has been separated from sequences which flank it
in a naturally occurring to state, e.g., a DNA fragment which has
been removed from the sequences which are normally adjacent to the
fragment, e.g., the sequences adjacent to the fragment in a genome
in which it naturally occurs. The term also applies to nucleic
acids which have been substantially purified from other components
which naturally accompany the nucleic acid, e.g., RNA or DNA or
proteins, which naturally accompany it in the cell. The term
therefore includes, for example, a recombinant DNA which is
incorporated into a vector, into an autonomously replicating
plasmid or virus, or into the genomic DNA of a prokaryote or
eukaryote, or which exists as a separate molecule (e.g., as a cDNA
or a genomic or cDNA fragment produced by PCR or restriction enzyme
digestion) independent of other sequences. It also includes a
recombinant DNA which is part of a hybrid gene encoding additional
polypeptide sequence.
[0069] As used herein, the term "lacritin polypeptide" and like
terms refers to peptides comprising the amino acid sequence of SEQ
ID NO: 4 and biologically active fragments, derivatives, and
homologs thereof. As used herein, the term "biologically active
fragments" or "bioactive fragment" of a lacritin polypeptide
encompasses natural or synthetic portions of the amino acid
sequence
TABLE-US-00002 (SEQ ID NO: 4)
MKFTTLLFLAAVAGALVYAEDASSDSTGADPAQEAGTSKPNEEISGPA
EPASPPETTTTAQETSAAAVQGTAKVTSSRQELNPLKSIVEKSILLTE
QALAKAGKGMHGGVPGGKQFIENGSEFAQKLLKKFSLLKPWA.
[0070] As used herein, the term "syndecan-1" refers to peptides
comprising the amino acid sequence of SEQ ID NO:12 and biologically
active fragments, derivatives, and homologs thereof. As used
herein, the term "biologically active fragments" or "bioactive
fragment" of a syndecan-1 polypeptide encompasses natural or
synthetic portions of the amino acid sequence
TABLE-US-00003 (SEQ ID NO: 12)
MRRAALWLWLCALALSLQPALPQIVATNLPPEDQDGSGDDSDNFSGSG
AGALQDITLSQQTPSTWKDTQLLTAIPTSPEPTGLEATAASTSTLPAG
EGPKEGEAVVLPEVEPGLTAREQEATPRPRETTQLPTTHQASTTTATT
AQEPATSHPHRDMQPGHHETSTPAGPSQADLHTPHTEDGGPSATERAA
EDGASSQLPAAEGSGEQDFTFETSGENTAVVAVEPDRRNQSPVDQGAT
GASQGLLDRKEVLGGVIAGGLVGLIFAVCLVGFMLYRMKKKDEGSYSL
EEPKQANGGAYQKPTKQEEFYA.
[0071] As used herein, the term "heparanase" refers to peptides
comprising the amino acid sequence of SEQ ID NO:13 and biologically
active fragments, derivatives, and homologs thereof. As used
herein, the term "biologically active fragments" or "bioactive
fragment" of a heparanase polypeptide encompasses natural or
synthetic portions of the amino acid sequence
TABLE-US-00004 (SEQ ID NO: 13)
MLLRSKPALPPPLMLLLLGPLGPLSPGALPRPAQAQDVVDLDFFTQEP
LHLVSPSFLSVTIDANLATDPRFLILLGSPKLRTLARGLSPAYLRFGG
TKTDFLIFDPKKESTFEERSYWQSQVNQDICKYGSIPPDVEEKLRLEW
PYQEQLLLREHYQKKFKNSTYSRSSVDVLYTFANCSGLDLIFGLNALL
RTADLQWNSSNAQLLLDYCSSKGYNISWELGNEPNSFLKKADIFINGS
QLGEDFIQLHKLLRKSTFKNAKLYGPDVGQPRRKTAKMLKSFLKAGGE
VIDSVTWHHYYLNGRTATKEDFLNPDVLDIFISSVQKVFQVVESTRPG
KKVWLGETSSAYGGGAPLLSDTFAAGFMWLDKLGLSARMGIEVVMRQV
FFGAGNYHLVDENFDPLPDYWLSLLFKKLVGTKVLMASVQGSKRRKLR
VYLHCTNTDNPRYKEGDLTLYAINLHNVTKYLRLPYPFSNKQVDKYLL
RPLGPHGLLSKSVQLNGLTLKMVDDQTLPPLMEKPLRPGSSLGLPAFS
YSFFVIRNAKVAACI.
[0072] As used herein, a "ligand" is a compound that specifically
binds to a target compound. A ligand (e.g., an antibody)
"specifically binds to" or "is specifically immunoreactive with" a
compound when the ligand functions in a binding reaction which is
determinative of the presence of the compound in a sample of
heterogeneous compounds. Thus, under designated assay (e.g.,
immunoassay) conditions, the ligand binds preferentially to a
particular compound and does not bind to a significant extent to
other compounds present in the sample. For example, an antibody
specifically binds under immunoassay conditions to an antigen
bearing an epitope against which the antibody was raised. A variety
of immunoassay formats may be used to select antibodies
specifically immunoreactive with a particular antigen. For example,
solid-phase ELISA immunoassays are routinely used to select
monoclonal antibodies specifically immunoreactive with an antigen.
See Harlow and Lane, 1988, Antibodies, A Laboratory Manual, Cold
Spring Harbor Publications, New York, for a description of
immunoassay formats and conditions that can be used to determine
specific immunoreactivity.
[0073] As used herein, the term "linkage" refers to a connection
between two groups. The connection can be either covalent or
non-covalent, including but not limited to ionic bonds, hydrogen
bonding, and hydrophobic/hydrophilic interactions.
[0074] As used herein, the term "linker" refers to a molecule that
joins two other molecules either covalently or noncovalently, e.g.,
through ionic or hydrogen bonds or van der Waals interactions.
[0075] "Ocular surface," as used herein, refers to the surface of
the eye, particularly the corneal surface.
[0076] The phrase "ocular surface-associated disease, disorder, or
condition," as used herein, refers to any disease, disorder or
condition which directly or indirectly causes, or can cause, any of
the problems or symptoms described herein regarding disease,
disorders, or conditions of the ocular surface.
[0077] "Operably linked" refers to a juxtaposition wherein the
components are configured so as to perform their usual function.
Thus, control sequences or promoters operably linked to a coding
sequence are capable of effecting the expression of the coding
sequence.
[0078] A "marker" is an atom or molecule that permits the specific
detection of a molecule comprising that marker in the presence of
similar molecules without such a marker. Markers include, for
example radioactive isotopes, antigenic determinants, nucleic acids
available for hybridization, chromophors, fluorophors,
chemiluminescent molecules, electrochemically detectable molecules,
molecules that provide for altered fluorescence-polarization or
altered light-scattering and molecules that allow for enhanced
survival of an cell or organism (i.e. a selectable marker). A
reporter gene is a gene that encodes for a marker.
[0079] A "polylinker" is a nucleic acid sequence that comprises a
series of three or more different restriction endonuclease
recognitions sequences closely spaced to one another (i.e. less
than 10 nucleotides between each site).
[0080] As used herein, the term "promoter/regulatory sequence"
means a nucleic acid sequence which is required for expression of a
gene product operably linked to the promoter/regulator sequence. In
some instances, this sequence may be the core promoter sequence and
in other instances, this sequence may also include an enhancer
sequence and other regulatory elements which are required for
expression of the gene product. The promoter/regulatory sequence
may, for example, be one which expresses the gene product in a
tissue specific manner.
[0081] A "constitutive promoter is a promoter which drives
expression of a gene to which it is operably linked, in a constant
manner in a cell. By way of example, promoters which drive
expression of cellular housekeeping genes are considered to be
constitutive promoters.
[0082] An "inducible" promoter is a nucleotide sequence which, when
operably linked with a polynucleotide which encodes or specifies a
gene product, causes the gene product to be produced in a living
cell substantially only when an inducer which corresponds to the
promoter is present in the cell.
[0083] A "tissue-specific" promoter is a nucleotide sequence which,
when operably linked with a polynucleotide which encodes or
specifies a gene product, causes the gene product to be produced in
a living cell substantially only if the cell is a cell of the
tissue type corresponding to the promoter.
[0084] As used herein, "nucleic acid," "DNA," and similar terms
also include nucleic acid analogs, i.e. analogs having other than a
phosphodiester backbone. For example, the so-called "peptide
nucleic acids," which are known in the art and have peptide bonds
instead of phosphodiester bonds in the backbone, are considered
within the scope of the present invention.
[0085] As used herein, the term "fragment" as applied to a nucleic
acid, may ordinarily be at least about 20 nucleotides in length,
typically, at least about 50 nucleotides, more typically, from
about 50 to about 100 nucleotides, preferably, at least about 100
to about 200 nucleotides, even more preferably, at least about 200
nucleotides to about 300 nucleotides, yet even more preferably, at
least about 300 to about 350, even more preferably, at least about
350 nucleotides to about 500 nucleotides, yet even more preferably,
at least about 500 to about 600, even more preferably, at least
about 600 nucleotides to about 620 nucleotides, yet even more
preferably, at least about 620 to about 650, and most preferably,
the nucleic acid fragment will be greater than about 650
nucleotides in length.
[0086] Unless otherwise specified, a "nucleotide sequence encoding
an amino acid sequence" includes all nucleotide sequences that are
degenerate versions of each other and that encode the same amino
acid sequence. Nucleotide sequences that encode proteins and RNA
may include introns.
[0087] The term "peptide" encompasses a sequence of 3 or more amino
acids wherein the amino acids are naturally occurring or synthetic
(non-naturally occurring) amino acids. Peptide mimetics include
peptides having one or more of the following modifications:
[0088] 1. peptides wherein one or more of the peptidyl --C(O)NR--
linkages (bonds) have been replaced by a non-peptidyl linkage such
as a --CH.sub.2-carbamate linkage
(--CH.sub.2OC(O)NR--), a phosphonate linkage, a
--CH.sub.2-sulfonamide (--CH 2-S(O).sub.2NR--) linkage, a urea
(--NHC(O)NH--) linkage, a --CH.sub.2-secondary amine linkage, or
with an alkylated peptidyl linkage (--C(O)NR--) wherein R is C1-C4
alkyl;
[0089] 2. peptides wherein the N-terminus is derivatized to a
--NRR1 group, to a NRC(O)R group, to a --NRC(O)OR group, to a
--NRS(O).sub.2R group, to a --NHC(O)NHR group where R and R1 are
hydrogen or C.sub.1-C.sub.4 alkyl with the proviso that R and R1
are not both hydrogen;
[0090] 3. peptides wherein the C terminus is derivatized to
--C(O)R2 where R 2 is selected from the group consisting of C1-C4
alkoxy, and --NR3R4 where R3 and R4 are independently selected from
the group consisting of hydrogen and C1-C4 alkyl.
[0091] Synthetic or non-naturally occurring amino acids refer to
amino acids which do not naturally occur in vivo but which,
nevertheless, can be incorporated into the peptide structures
described herein. The resulting "synthetic peptide" contain amino
acids other than the 20 naturally occurring, genetically encoded
amino acids at one, two, or more positions of the peptides. For
instance, naphthylalanine can be substituted for tryptophan to
facilitate synthesis. Other synthetic amino acids that can be
substituted into peptides include L-hydroxypropyl,
L-3,4-dihydroxyphenylalanyl, alpha-amino acids such as
L-alpha-hydroxylysyl and D-alpha-methylalanyl,
L-alpha.-methylalanyl, beta.-amino acids, and isoquinolyl. D amino
acids and non-naturally occurring synthetic amino acids can also be
incorporated into the peptides. Other derivatives include
replacement of the naturally occurring side chains of the 20
genetically encoded amino acids (or any L or D amino acid) with
other side chains.
[0092] The term "fusion polypeptide" or "fusion protein" refers to
a chimeric protein containing a reference protein (e.g., lacritin)
joined at the N- and/or C-terminus to one or more heterologous
sequences (e.g., a non lacritin polypeptide, such as syndecan).
Polypeptide molecules are said to have an "amino terminus" (N
terminus) and a "carboxy terminus" (C terminus) because peptide
linkages occur between the backbone amino group of a first amino
acid residue and the backbone carboxyl group of a second amino acid
residue. The terms "N terminal" and "C terminal" in reference to
polypeptide sequences refer to regions of polypeptides including
portions of the N terminal and C terminal regions of the
polypeptide, respectively. A sequence that includes a portion of
the N terminal region of polypeptide includes amino acids
predominantly from the N terminal half of the polypeptide chain,
but is not limited to such sequences. For example, an N terminal
sequence may include an interior portion of the polypeptide
sequence including bases from both the N terminal and C terminal
halves of the polypeptide. The same applies to C terminal regions.
N terminal and C terminal regions may, but need not, include the
amino acid defining the ultimate N terminus and C terminus of the
polypeptide, respectively.
[0093] The fusion proteins of the invention may be prepared by
recombinant methods or by solid phase chemical peptide synthesis
methods. Such methods have been known in the art since the early
1960's (Merrifield, 1963) (See also Stewart et al., Solid Phase
Peptide Synthesis, 2 ed., Pierce Chemical Co., Rockford, Ill., pp.
11-12)) and have recently been employed in commercially available
laboratory peptide design and synthesis kits (Cambridge Research
Biochemicals). Such commercially available laboratory kits have
generally utilized the teachings of Geysen et al. (1984) and
provide for synthesizing peptides upon the tips of a multitude of
"rods" or "pins" all of which are connected to a single plate. When
such a system is utilized, a plate of rods or pins is inverted and
inserted into a second plate of corresponding wells or reservoirs,
which contain solutions for attaching or anchoring an appropriate
amino acid to the pin's or rod's tips. By repeating such a process
step, e.g., inverting and inserting the rod's and pin's tips into
appropriate solutions, amino acids are built into desired peptides.
In addition, a number of available FMOC peptide synthesis systems
are available. For example, assembly of a polypeptide or fragment
can be carried out on a solid support using an Applied Biosystems,
Inc. Model 431A automated peptide synthesizer. Such equipment
provides ready access to the peptides of the invention, either by
direct synthesis or by synthesis of a series of fragments that can
be coupled using other known techniques.
[0094] The invention also includes a stable cell line that
expresses a lacritin/syndecan-1 fusion protein, as well as an
expression cassette comprising a nucleic acid molecule encoding the
lacritin/syndecan-1 fusion protein, and a vector capable of
expressing the nucleic acid molecule of the invention in a host
cell. Preferably, the expression cassette comprises a promoter,
e.g., a constitutive or regulatable promoter, operably linked to
the nucleic acid sequence. In one embodiment, the expression
cassette contains an inducible promoter. Also provided is a host
cell, e.g., a prokaryotic cell or an eukaryotic cell such as a
plant or vertebrate cell, e.g., a mammalian cell, including but not
limited to a human, non-human primate, canine, feline, bovine,
equine, ovine or rodent (e.g., rabbit, rat, ferret or mouse) cell,
which comprises the expression cassette or vector of the invention,
and a kit which comprises the nucleic acid molecule, expression
cassette, vector, host cell or lacritin/syndecan-1 fusion
protein.
[0095] As used herein, the term "pharmaceutically acceptable
carrier" includes any of the standard pharmaceutical carriers, such
as a phosphate buffered saline solution, water, emulsions such as
an oil/water or water/oil emulsion, and various types of wetting
agents. The term also encompasses any of the agents approved by a
regulatory agency of the US Federal government or listed in the US
Pharmacopeia for use in animals, including humans.
[0096] A "promoter" is a DNA sequence that directs the
transcription of a DNA sequence, such as the nucleic acid coding
sequence of a gene. Typically, a promoter is located in the 5'
region of a gene, proximal to the transcriptional start site of a
structural gene. Promoters can be inducible (the rate of
transcription changes in response to a specific agent), tissue
specific (expressed only in some tissues), temporal specific
(expressed only at certain times) or constitutive (expressed in all
tissues and at a constant rate of transcription).
[0097] A "core promoter" contains essential nucleotide sequences
for promoter function, including the TATA box and start of
transcription. By this definition, a core promoter may or may not
have detectable activity in the absence of specific sequences that
enhance the activity or confer tissue specific activity.
[0098] As used herein, the term "purified" and like terms relate to
the isolation of a molecule or compound in a form that is
substantially free of contaminants normally associated with the
molecule or compound in a native or natural environment. The term
"purified" does not necessarily indicate that complete purity of
the particular molecule has been achieved during the process. A
"highly purified" compound as used herein refers to a compound that
is greater than 90% pure.
[0099] A "subject" of experimentation, diagnosis or treatment is an
animal, including a human.
[0100] The term "substantially pure" describes a compound, e.g., a
protein or polypeptide which has been separated from components
which naturally accompany it. Typically, a compound is
substantially pure when at least 10%, more preferably at least 20%,
more preferably at least 50%, more preferably at least 60%, more
preferably at least 75%, more preferably at least 90%, and most
preferably at least 99% of the total material (by volume, by wet or
dry weight, or by mole percent or mole fraction) in a sample is the
compound of interest. Purity can be measured by any appropriate
method, e.g., in the case of polypeptides by column chromatography,
gel electrophoresis, or HPLC analysis. A compound, e.g., a protein,
is also substantially purified when it is essentially free of
naturally associated components or when it is separated from the
native contaminants which accompany it in its natural state.
[0101] A "substantially pure nucleic acid", as used herein, refers
to a nucleic acid sequence, segment, or fragment which has been
purified from the sequences which flank it in a naturally occurring
state, e.g., a DNA fragment which has been removed from the
sequences which are normally adjacent to the fragment e.g., the
sequences adjacent to the fragment in a genome in which it
naturally occurs. The term also applies to nucleic acids which have
been substantially purified from other components which naturally
accompany the nucleic acid, e.g., RNA or DNA or proteins which
naturally accompany it in the cell.
[0102] A "therapeutic" treatment is a treatment administered to a
subject who exhibits signs of pathology for the purpose of
diminishing or eliminating those signs.
[0103] A "therapeutically effective amount" of a compound is that
amount of compound which is sufficient to provide a beneficial
effect to the subject to which the compound is administered.
[0104] As used herein, the term "treating" includes prophylaxis of
the specific disorder or condition, or alleviation of the symptoms
associated with a specific disorder or condition and/or preventing
or eliminating said symptoms. A "prophylactic" treatment is a
treatment administered to a subject who does not exhibit signs of a
disease or exhibits only early signs of the disease for the purpose
of decreasing the risk of developing pathology associated with the
disease. As used herein, the term "treating" includes alleviating
the symptoms associated with a specific disease, disorder or
condition and/or preventing or eliminating said symptoms.
[0105] A "vector" is also meant to include a composition of matter
which comprises an isolated nucleic acid and which can be used to
deliver the isolated nucleic acid to the interior of a cell.
Numerous vectors are known in the art including, but not limited
to, linear polynucleotides, polynucleotides associated with ionic
or amphiphilic compounds, plasmids, and viruses. Thus, the term
"vector" includes an autonomously replicating plasmid or a virus.
The term should also be construed to include non-plasmid and
non-viral compounds which facilitate transfer of nucleic acid into
cells, such as, for example, polylysine compounds, liposomes, and
the like. Examples of viral vectors include, but are not limited
to, adenoviral vectors, adeno-associated virus vectors, retroviral
vectors, plasmids, cosmids, lambda phage vectors, and the like.
[0106] "Expression vector" refers to a vector comprising a
recombinant polynucleotide comprising expression control sequences
operatively linked to a nucleotide sequence to be expressed. An
expression vector comprises sufficient cis-acting elements for
expression; other elements for expression can be supplied by the
host cell or in an in vitro expression system. Expression vectors
include all those known in the art, such as cosmids, plasmids
(e.g., naked or contained in liposomes) and viruses that
incorporate the recombinant polynucleotide.
[0107] As used herein, the term "wound" relates to a physical tear
or rupture to a tissue or cell layer. A wound may occur by any
physical insult, including a surgical procedure.
EMBODIMENTS OF THE INVENTION
[0108] The present invention is directed to uses of a human growth
factor-like molecule, "lacritin," and compositions comprising
lacritin, or fragments, derivatives, or homologs thereof, and to
its interaction with syndecan, and regulation of the pathways
effected by such interaction. The invention also encompasses
regulation and treatment of diseases, disorders, and conditions by
regulating lacritin, lacritin-syndecan interactions, syndecan, and
the pathways downstream from lacritin-syndecan interactions. The
invention also encompasses use of nucleic acid sequences encoding
lacritin, as well as the nucleic acid regulatory elements
controlling the expression of lacritin.
[0109] The full length `lacritin` cDNA was previously cloned from a
human lacrimal gland library, and the corresponding genomic gene
has been cloned and sequenced, including 5.2 kb of upstream and 2.8
kb of downstream genomic sequence.
[0110] In one embodiment, the present invention is directed to use
of a purified polypeptide comprising the amino acid sequence of SEQ
ID NOs: 4, 12 or 13, a bioactive fragment of SEQ ID NOs: 4, 12 or
13, or an amino acid sequence that differs from SEQ ID NOs: 4, 12
or 13 by one or more conservative amino acid substitutions. More
preferably, the purified polypeptide comprises an amino acid
sequence that differs from SEQ ID NOs: 4, 12 or 13 by 20 or less
conservative amino acid substitutions, and more preferably by 10 or
less conservative amino acid substitutions. Alternatively, the
polypeptide may comprise an amino acid sequence that differs from
SEQ ID NOs: 4, 12 or 13 by 1 to 5 alterations, wherein the
alterations are independently selected from a single amino acid
deletion, insertion, or substitution. Alternatively, the
polypeptide comprises an amino acid sequence that is at about 85%,
90%, 95% or 99% identical to SEQ ID NOs: 4, 12 or 13. In one
preferred embodiment a composition is provided comprising a
polypeptide, selected from the group consisting of SEQ ID NOs: 4,
12 or 13 and a pharmaceutically acceptable carrier. In another
preferred embodiment, the polypeptide or fragments thereof are of
the mature processed lacritin selected from the group of fragments
with up to 25 amino acids deleted from the C-terminus. In another
embodiment, up to 25 amino acids are deleted from the N-terminus of
SEQ ID NO:4, the full length lacritin.
[0111] Physiological experiments recently performed using
recombinant lacritin generated by E. coli suggests that lacritin is
also a survival factor, i.e., longevity in cell culture was
promoted by the addition of physiological amounts of lacritin.
Methods for measuring wound healing are known in the art (reviewed
in Woo et al., Experimental Eye Research, 80:633-642, 2000).
Methods for measuring cell survival are known in the art and
include various cellular, molecular, biochemical, and histological
techniques.
[0112] Lacritin is naturally produced in moderately large
quantities by the lacrimal gland for release into the corneal tear
film. The therapeutic potential of lacritin, and therefore the
lacritin-syndecan interactions in promoting the health of the
ocular surface is therefore considerable, particularly as
environmental exposure to pollutants and UV exposure increases, and
as the proportion of the population, suffering from Dry Eye
expands.
[0113] The cornea is the main refracting surface of the eye and is
vulnerable to environmental hazards or insult including exposure
(direct trauma, drying, radiant and ionizing energy), infectious
agents (bacteria, viruses--notably herpes simplex and herpes
zoster--fungi, and parasites), and inflammation, sometimes in
association with systemic dermatologic disorders such as atopic
dermatitis, cicatricial pemphigoid, rosacea, and erythema
multiforme (Stevens-Johnson syndrome). Bacteria include
pseudomonas. Keratitis is an inflammation or infection of the
cornea. It is often associated with inflammation of the iris
(iritis) or of the uveal tract--the iris, ciliary body, and choroid
(uveitis). Keratitis combined with uveitis or iritis is seen
commonly in Reiter's disease and occasionally Behcet's disease.
Keratitis and uveitis may also occur with herpes simplex infection,
in sarcoidosis, and in collagen vascular diseases.
[0114] As described above, a host of mediators are implicated in
the development and progression of corneal inflammation, such as
the proinflammatory cytokines TNF-.alpha., IL-1.beta., IL-6, and
the chemokine IL-8. Also involved are the arachidonic acid-derived
eicosanoids which are produced by the activity of cyclooxygenases
(primarily PGE2), lipooxygenases (12 (s)-HETE) and cytochrome P450
(12 (r)-HETE). Therefore, in one embodiment of the invention, any
method for enhancing lacritin-syndecan interactions and the signals
resulting therefrom is useful as an antagonist to inflammatory
processes such as those induced or supplemented by proinflammatory
agents such as proinflammatory cytokines.
[0115] In accordance with one embodiment, a method of reducing or
preventing ocular cell death in a mammalian species after contact
with an environmental insult, or in response to an
ocular-associated disease, disorder, or condition is provided. The
method comprises the steps of contacting the cells that have been
exposed to the environmental insult to a composition comprising
lacritin, or a fragment, derivative, or homolog thereof, as well as
methods to enhance lacritin-syndecan interaction. As used herein,
cells that are "exposed" to the environmental insult include those
cells that have been directly contacted by the environmental
insult, as well as those cells that suffer indirectly as a result
of direct contact of other cells with the environmental insult. In
one embodiment, the ocular cells comprise the corneal epithelial
cells. In one embodiment, the exposed cells are contacted with a
topically administered ophthalmic formulation comprising a lacritin
polypeptide, or a derivative, fragment, or homolog thereof, as well
as compounds to enhance lacritin-syndecan interactions.
[0116] The lacritin comprising compositions or compositions
comprising compounds which enhance lacritin-syndecan interaction of
the present invention can be administered prophylactically to
promote corneal epithelial cell survival in the presence of common
environmental insults such as exposure to UV exposure or
pollutants, particularly for those individuals that face excessive
exposure to such elements. In another embodiment, the lacritin
comprising compositions of the present invention are used to
regulate an immune response to inflammation and/or bacterial
infection. In another embodiment, a lacritin comprising composition
can be administered to aid in the healing process following a
surgical procedure to the eye, such as cataract or other
vision-corrective surgical procedures. The invention encompasses
all surgical procedures of the eye, including laser procedures.
[0117] In accordance with one embodiment, a method is provided for
treating infections of the eye. The method comprises the step of
topically administering a composition comprising a lacritin
polypeptide to the eye. In one embodiment, the composition further
comprises an anti-microbial agent. Suitable ophthalmic
anti-microbial agents are known to those skilled in the art and
include those described in U.S. Pat. Nos. 5,300,296, 6,316,669,
6,365,636 and 6,592,907, the disclosures of which are incorporated
herein. Examples of anti-microbial agents suitable for use in
accordance with the present invention include benzalkonium
chloride, benzethonium chloride, benzyl alcohol, chlorobutanol,
chlorhexidine digluconate or diacetate, methyl and propyl
hydroxybenzoate (parabens), phenylethyl alcohol, phenylmercuric
acetate or nitrate, sorbic acid, and thimerosal.
[0118] Current tear supplements are not popular with patients, in
part because the relief obtained from such products is very brief
(less than 15 min). Examples of the tear substitution approach
include the use of buffered, isotonic saline solutions, aqueous
solutions containing water soluble polymers that render the
solutions more viscous and thus less easily shed by the eye. Tear
reconstitution is also attempted by providing one or more
components of the tear film such as phospholipids and oils.
Examples of these treatment approaches are disclosed in U.S. Pat.
No. 4,131,651 (Shah et al.), U.S. Pat. No. 4,370,325 (Packman),
U.S. Pat. No. 4,409,205 (Shively), U.S. Pat. Nos. 4,744,980 and
4,883,658 (Holly), U.S. Pat. No. 4,914,088 (Glonek), U.S. Pat. No.
5,075,104 (Gressel et al.) and U.S. Pat. No. 5,294,607 (Glonek et
al.) the disclosures of which are incorporated herein. Existing
ophthalmic formulations may also include TGF-beta, corticosteroids,
or androgens. All are non-specific for the eye and have systemic
effects. In contrast, lacritin is highly restricted to the eye and
is a natural constituent of human tears and the tear film.
[0119] An ophthalmic formulation comprising lacritin, or fragments,
homologs, or derivatives thereof (for example, an artificial tear
fluids containing lacritin), is highly desirable due to the
activity of lacritin and its localized effects. In accordance with
one embodiment of the invention, compositions comprising lacritin
are used to enhance corneal wound healing, and/or treat patients
having deficient tear output. The lacritin compositions of the
present invention can be formulated using standard ophthalmic
components, and preferably, the compositions are formulated as
solutions, suspensions, and other dosage forms for topical
administration. Aqueous solutions are generally preferred, based on
ease of formulation, biological compatibility (especially in view
of the malady to be treated, e.g., dry eye-type diseases and
disorders), as well as a patient's ability to easily administer
such compositions by means of instilling one to two drops of the
solutions in the affected eyes. However, the compositions may also
be suspensions, viscous or semi-viscous gels, or other types of
solid or semi-solid compositions.
[0120] The compositions of the present invention may include
surfactants, preservative agents, antioxidants, tonicity agents,
buffers, preservatives, co-solvents and viscosity building agents.
Various surfactants useful in topical ophthalmic formulations may
be employed in the present compositions. These surfactants may aid
in preventing chemical degradation of lacritin and also prevent the
lacritin from binding to the containers in which the compositions
are packaged. Examples of surfactants include, but are not limited
to: Cremophor.RTM. EL, polyoxyl 20 ceto stearyl ether, polyoxyl 40
hydrogenated castor oil, polyoxyl 23 lauryl ether and poloxamer 407
may be used in the compositions. Antioxidants may be added to
compositions of the present invention to protect the lacritin
polypeptide from oxidation during storage. Examples of such
antioxidants include, but are not limited to, vitamin E and analogs
thereof, ascorbic acid and derivatives, and butylated
hydroxyanisole (BHA).
[0121] Existing artificial tears formulations can also be used as
pharmaceutically acceptable carriers for the lacritin active agent.
Thus in one embodiment, lacritin is used to improve existing
artificial tear products for Dry Eye syndromes, as well as develop
products to aid corneal wound healing. Examples of artificial tears
compositions useful as carriers include, but are not limited to,
commercial products, such as Tears Naturale.RTM., Tears Naturale
II.RTM., Tears Naturale Free.RTM., and Bion Tears.RTM. (Alcon
Laboratories, Inc., Fort Worth, Tex.). Examples of other
phospholipid carrier formulations include those disclosed in U.S.
Pat. No. 4,804,539 (Guo et al.), U.S. Pat. No. 4,883,658 (Holly),
U.S. Pat. No. 4,914,088 (Glonek), U.S. Pat. No. 5,075,104 (Gressel
et al.), U.S. Pat. No. 5,278,151 (Korb et al.), U.S. Pat. No.
5,294,607 (Glonek et al.), U.S. Pat. No. 5,371,108 (Korb et al.),
U.S. Pat. No. 5,578,586 (Glonek et al.); the foregoing patents are
incorporated herein by reference to the extent they disclose
phospholipid compositions useful as phospholipid carriers of the
present invention.
[0122] Other compounds may also be added to the ophthalmic
compositions of the present invention to increase the viscosity of
the carrier. Examples of viscosity enhancing agents include, but
are not limited to: polysaccharides, such as hyaluronic acid and
its salts, chondroitin sulfate and its salts, dextrans, various
polymers of the cellulose family; vinyl polymers; and acrylic acid
polymers. In general, the phospholipid carrier or artificial tears
carrier compositions will exhibit a viscosity of 1 to 400
centipoises ("cps"). Preferred compositions containing artificial
tears or phospholipid carriers and will exhibit a viscosity of
about 25 cps.
[0123] Topical ophthalmic products are typically packaged in
multidose form. Preservatives are thus required to prevent
microbial contamination during use. Suitable preservatives include:
benzalkonium chloride, chlorobutanol, benzododecinium bromide,
methyl paraben, propyl paraben, phenylethyl alcohol, edetate
disodium, sorbic acid, polyquaternium-1, or other agents known to
those skilled in the art. Such preservatives are typically employed
at a level of from 0.001 to 1.0% w/v. Unit dose compositions of the
present invention will be sterile, but typically unpreserved. Such
compositions, therefore, generally will not contain
preservatives.
[0124] Because the gene promoter regulating lacritin gene
expression is the most specific of any previously described
lacrimal gland gene, the regulatory elements of this gene could be
used to express other gene products in the eye. In particular, the
lacritin gene promoter can be operably linked to a wide variety of
exogenous genes to regulate the expression of the gene products to
the lacrimal gland and/or used as gene therapy to treat Dry Eye
syndromes.
[0125] The peptides of the present invention may be readily
prepared by standard, well-established techniques, such as
solid-phase peptide synthesis (SPPS) as described by Stewart et al.
in Solid Phase Peptide Synthesis, 2nd Edition, 1984, Pierce
Chemical Company, Rockford, Ill.; and as described by Bodanszky and
Bodanszky in The Practice of Peptide Synthesis, 1984,
Springer-Verlag, New York. At the outset, a suitably protected
amino acid residue is attached through its carboxyl group to a
derivatized, insoluble polymeric support, such as cross-linked
polystyrene or polyamide resin. "Suitably protected" refers to the
presence of protecting groups on both the .alpha.-amino group of
the amino acid, and on any side chain functional groups. Side chain
protecting groups are generally stable to the solvents, reagents
and reaction conditions used throughout the synthesis, and are
removable under conditions which will not affect the final peptide
product. Stepwise synthesis of the oligopeptide is carried out by
the removal of the N-protecting group from the initial amino acid,
and couple thereto of the carboxyl end of the next amino acid in
the sequence of the desired peptide. This amino acid is also
suitably protected. The carboxyl of the incoming amino acid can be
activated to react with the N-terminus of the support-bound amino
acid by formation into a reactive group such as formation into a
carbodiimide, a symmetric acid anhydride or an "active ester" group
such as hydroxybenzotriazole or pentafluorophenly esters.
[0126] Examples of solid phase peptide synthesis methods include
the BOC method which utilized tert-butyloxcarbonyl as the
.alpha.-amino protecting group, and the FMOC method which utilizes
9-fluorenylmethyloxcarbonyl to protect the .alpha.-amino of the
amino acid residues, both methods of which are well known by those
of skill in the art.
[0127] Incorporation of N- and/or C-blocking groups can also be
achieved using protocols conventional to solid phase peptide
synthesis methods. For incorporation of C-terminal blocking groups,
for example, synthesis of the desired peptide is typically
performed using, as solid phase, a supporting resin that has been
chemically modified so that cleavage from the resin results in a
peptide having the desired C-terminal blocking group. To provide
peptides in which the C-terminus bears a primary amino blocking
group, for instance, synthesis is performed using a
p-methylbenzhydrylamine (MBHA) resin so that, when peptide
synthesis is completed, treatment with hydrofluoric acid releases
the desired C-terminally amidated peptide. Similarly, incorporation
of an N-methylamine blocking group at the C-terminus is achieved
using N-methylaminoethyl-derivatized DVB, resin, which upon HF
treatment releases a peptide bearing an N-methylamidated
C-terminus. Blockage of the C-terminus by esterification can also
be achieved using conventional procedures. This entails use of
resin/blocking group combination that permits release of side-chain
peptide from the resin, to allow for subsequent reaction with the
desired alcohol, to form the ester function. FMOC protecting group,
in combination with DVB resin derivatized with methoxyalkoxybenzyl
alcohol or equivalent linker, can be used for this purpose, with
cleavage from the support being effected by TFA in
dicholoromethane. Esterification of the suitably activated carboxyl
function e.g. with DCC, can then proceed by addition of the desired
alcohol, followed by deprotection and isolation of the esterified
peptide product.
[0128] Incorporation of N-terminal blocking groups can be achieved
while the synthesized peptide is still attached to the resin, for
instance by treatment with a suitable anhydride and nitrile. To
incorporate an acetyl-blocking group at the N-terminus, for
instance, the resin-coupled peptide can be treated with 20% acetic
anhydride in acetonitrile. The N-blocked peptide product can then
be cleaved from the resin, deprotected and subsequently
isolated.
[0129] To ensure that the peptide obtained from either chemical or
biological synthetic techniques is the desired peptide, analysis of
the peptide composition should be conducted. Such amino acid
composition analysis may be conducted using high-resolution mass
spectrometry to determine the molecular weight of the peptide.
Alternatively, or additionally, the amino acid content of the
peptide can be confirmed by hydrolyzing the peptide in aqueous
acid, and separating, identifying and quantifying the components of
the mixture using HPLC, or an amino acid analyzer. Protein
sequenators, which sequentially degrade the peptide and identify
the amino acids in order, may also be used to determine definitely
the sequence of the peptide.
[0130] Prior to its use, the peptide is purified to remove
contaminants. In this regard, it will be appreciated that the
peptide will be purified to meet the standards set out by the
appropriate regulatory agencies. Any one of a number of a
conventional purification procedures may be used to attain the
required level of purity including, for example, reversed-phase
high-pressure liquid chromatography (HPLC) using an alkylated
silica column such as C4-, C8- or C18-silica. A gradient mobile
phase of increasing organic content is generally used to achieve
purification, for example, acetonitrile in an aqueous buffer,
usually containing a small amount of trifluoroacetic acid.
Ion-exchange chromatography can be also used to separate peptides
based on their charge.
[0131] It will be appreciated, of course, that the peptides or
antibodies, derivatives, or fragments thereof may incorporate amino
acid residues which are modified without affecting activity. For
example, the termini may be derivatized to include blocking groups,
i.e. chemical substituents suitable to protect and/or stabilize the
N- and C-termini from "undesirable degradation", a term meant to
encompass any type of enzymatic, chemical or biochemical breakdown
of the compound at its termini which is likely to affect the
function of the compound, i.e. sequential degradation of the
compound at a terminal end thereof.
[0132] Blocking groups include protecting groups conventionally
used in the art of peptide chemistry which will not adversely
affect the in vivo activities of the peptide. For example, suitable
N-terminal blocking groups can be introduced by alkylation or
acylation of the N-terminus. Examples of suitable N-terminal
blocking groups include C.sub.1-C.sub.5 branched or unbranched
alkyl groups, acyl groups such as formyl and acetyl groups, as well
as substituted forms thereof, such as the acetamidomethyl (Acm)
group. Desamino analogs of amino acids are also useful N-terminal
blocking groups, and can either be coupled to the N-terminus of the
peptide or used in place of the N-terminal reside. Suitable
C-terminal blocking groups, in which the carboxyl group of the
C-terminus is either incorporated or not, include esters, ketones
or amides. Ester or ketone-forming alkyl groups, particularly lower
alkyl groups such as methyl, ethyl and propyl, and amide-forming
amino groups such as primary amines (--NH.sub.2), and mono- and
di-alkylamino groups such as methylamino, ethylamino,
dimethylamino, diethylamino, methylethylamino and the like are
examples of C-terminal blocking groups. Descarboxylated amino acid
analogues such as agmatine are also useful C-terminal blocking
groups and can be either coupled to the peptide's C-terminal
residue or used in place of it. Further, it will be appreciated
that the free amino and carboxyl groups at the termini can be
removed altogether from the peptide to yield desamino and
descarboxylated forms thereof without affect on peptide
activity.
[0133] Other modifications can also be incorporated without
adversely affecting the activity and these include, but are not
limited to, substitution of one or more of the amino acids in the
natural L-isomeric form with amino acids in the D-isomeric form.
Thus, the peptide may include one or more D-amino acid resides, or
may comprise amino acids which are all in the D-form. Retro-inverso
forms of peptides in accordance with the present invention are also
contemplated, for example, inverted peptides in which all amino
acids are substituted with D-amino acid forms.
[0134] Acid addition salts of the present invention are also
contemplated as functional equivalents. Thus, a peptide in
accordance with the present invention treated with an inorganic
acid such as hydrochloric, hydrobromic, sulfuric, nitric,
phosphoric, and the like, or an organic acid such as an acetic,
propionic, glycolic, pyruvic, oxalic, malic, malonic, succinic,
maleic, fumaric, tataric, citric, benzoic, cinnamie, mandelic,
methanesulfonic, ethanesulfonic, p-toluenesulfonic, salicyclic and
the like, to provide a water soluble salt of the peptide is
suitable for use in the invention.
[0135] The present invention also provides for analogs of proteins.
Analogs can differ from naturally occurring proteins or peptides by
conservative amino acid sequence differences or by modifications
which do not affect sequence, or by both.
[0136] For example, conservative amino acid changes may be made,
which although they alter the primary sequence of the protein or
peptide, do not normally alter its function. To that end, 10 or
more conservative amino acid changes typically have no effect on
peptide function. Conservative amino acid substitutions typically
include substitutions within the following groups:
[0137] glycine, alanine;
[0138] valine, isoleucine, leucine;
[0139] aspartic acid, glutamic acid;
[0140] asparagine, glutamine;
[0141] serine, threonine;
[0142] lysine, arginine;
[0143] phenylalanine, tyrosine.
[0144] Modifications (which do not normally alter primary sequence)
include in vivo, or in vitro chemical derivatization of
polypeptides, e.g., acetylation, or carboxylation. Also included
are modifications of glycosylation, e.g., those made by modifying
the glycosylation patterns of a polypeptide during its synthesis
and processing or in further processing steps; e.g., by exposing
the polypeptide to enzymes which affect glycosylation, e.g.,
mammalian glycosylating or deglycosylating enzymes. Also embraced
are sequences which have phosphorylated amino acid residues, e.g.,
phosphotyrosine, phosphoserine, or phosphothreonine.
[0145] Also included are polypeptides or antibody fragments which
have been modified using ordinary molecular biological techniques
so as to improve their resistance to proteolytic degradation or to
optimize solubility properties or to render them more suitable as a
therapeutic agent. Analogs of such polypeptides include those
containing residues other than naturally occurring L-amino acids,
e.g., D-amino acids or non-naturally occurring synthetic amino
acids. The peptides of the invention are not limited to products of
any of the specific exemplary processes listed herein.
[0146] Substantially pure protein obtained as described herein may
be purified by following known procedures for protein purification,
wherein an immunological, enzymatic or other assay is used to
monitor purification at each stage in the procedure. Protein
purification methods are well known in the art, and are described,
for example in Deutscher et al. (ed., 1990, Guide to Protein
Purification, Harcourt Brace Jovanovich, San Diego).
[0147] The invention also includes a kit comprising the composition
of the invention and an instructional material which describes
administering the composition to a subject. In another embodiment,
this kit comprises a (preferably sterile) solvent suitable for
dissolving or suspending the composition of the invention prior to
administering the composition.
[0148] As used herein, the term "physiologically acceptable" ester
or salt means an ester or salt form of the active ingredient which
is compatible with any other ingredients of the pharmaceutical
composition, which is not deleterious to the subject to which the
composition is to be administered.
[0149] The formulations of the pharmaceutical compositions
described herein may be prepared by any method known or hereafter
developed in the art of pharmacology. In general, such preparatory
methods include the step of bringing the active ingredient into
association with a carrier or one or more other accessory
ingredients, and then, if necessary or desirable, shaping or
packaging the product into a desired single- or multi-dose
unit.
[0150] Although the descriptions of pharmaceutical compositions
provided herein are principally directed to pharmaceutical
compositions which are suitable for ethical administration to
humans, it will be understood by the skilled artisan that such
compositions are generally suitable for administration to animals
of all sorts. Modification of pharmaceutical compositions suitable
for administration to humans in order to render the compositions
suitable for administration to various animals is well understood,
and the ordinarily skilled veterinary pharmacologist can design and
perform such modification with merely ordinary, if any,
experimentation. Subjects to which administration of the
pharmaceutical compositions of the invention is contemplated
include, but are not limited to, humans and other primates, mammals
including commercially relevant mammals such as cattle, pigs,
horses, sheep, cats, and dogs, and to birds including commercially
relevant birds such as chickens, ducks, geese, and turkeys.
[0151] Pharmaceutical compositions that are useful in the methods
of the invention may be prepared, packaged, or sold in formulations
suitable for oral, rectal, vaginal, parenteral, intravenous,
topical, pulmonary, intranasal, buccal, ophthalmic, intrathecal or
another route of administration. Other contemplated formulations
include projected nanoparticles, liposomal preparations, resealed
erythrocytes containing the active ingredient, and
immunologically-based formulations.
[0152] A pharmaceutical composition of the invention may be
prepared, packaged, or sold in bulk, as a single unit dose, or as a
plurality of single unit doses. As used herein, a "unit dose" is
discrete amount of the pharmaceutical composition comprising a
predetermined amount of the active ingredient. The amount of the
active ingredient is generally equal to the dosage of the active
ingredient which would be administered to a subject or a convenient
fraction of such a dosage such as, for example, one-half or
one-third of such a dosage.
[0153] The relative amounts of the active ingredient, the
pharmaceutically acceptable carrier, and any additional ingredients
in a pharmaceutical composition of the invention will vary,
depending upon the identity, size, and condition of the subject
treated and further depending upon the route by which the
composition is to be administered. By way of example, the
composition may comprise between 0.1% and 100% (w/w) active
ingredient.
[0154] In addition to the active ingredient, a pharmaceutical
composition of the invention may further comprise one or more
additional pharmaceutically active agents. Particularly
contemplated additional agents include anti-emetics and scavengers
such as cyanide and cyanate scavengers.
[0155] Controlled- or sustained-release formulations of a
pharmaceutical composition of the invention may be made using
conventional technology.
[0156] A formulation of a pharmaceutical composition of the
invention suitable for oral administration may be prepared,
packaged, or sold in the form of a discrete solid dose unit
including, but not limited to, a tablet, a hard or soft capsule, a
cachet, a troche, or a lozenge, each containing a predetermined
amount of the active ingredient. Other formulations suitable for
oral administration include, but are not limited to, a powdered or
granular formulation, an aqueous or oily suspension, an aqueous or
oily solution, or an emulsion.
[0157] As used herein, an "oily" liquid is one which comprises a
carbon-containing liquid molecule and which exhibits a less polar
character than water.
[0158] Liquid formulations of a pharmaceutical composition of the
invention which are suitable for oral administration may be
prepared, packaged, and sold either in liquid form or in the form
of a dry product intended for reconstitution with water or another
suitable vehicle prior to use.
[0159] Liquid suspensions may be prepared using conventional
methods to achieve suspension of the active ingredient in an
aqueous or oily vehicle. Aqueous vehicles include, for example,
water and isotonic saline. Oily vehicles include, for example,
almond oil, oily esters, ethyl alcohol, vegetable oils such as
arachis, olive, sesame, or coconut oil, fractionated vegetable
oils, and mineral oils such as liquid paraffin. Liquid suspensions
may further comprise one or more additional ingredients including,
but not limited to, suspending agents, dispersing or wetting
agents, emulsifying agents, demulcents, preservatives, buffers,
salts, flavorings, coloring agents, and sweetening agents. Oily
suspensions may further comprise a thickening agent. Known
suspending agents include, but are not limited to, sorbitol syrup,
hydrogenated edible fats, sodium alginate, polyvinylpyrrolidone,
gum tragacanth, gum acacia, and cellulose derivatives such as
sodium carboxymethylcellulose, methylcellulose,
hydroxypropylmethylcellulose.
[0160] Known dispersing or wetting agents include, but are not
limited to, naturally-occurring phosphatides such as lecithin,
condensation products of an alkylene oxide with a fatty acid, with
a long chain aliphatic alcohol, with a partial ester derived from a
fatty acid and a hexitol, or with a partial ester derived from a
fatty acid and a hexitol anhydride (e.g. polyoxyethylene stearate,
heptadecaethyleneoxycetanol, polyoxyethylene sorbitol monooleate,
and polyoxyethylene sorbitan monooleate, respectively). Known
emulsifying agents include, but are not limited to, lecithin and
acacia. Known preservatives include, but to are not limited to,
methyl, ethyl, or n-propyl-para-hydroxybenzoates, ascorbic acid,
and sorbic acid. Known sweetening agents include, for example,
glycerol, propylene glycol, sorbitol, sucrose, and saccharin. Known
thickening agents for oily suspensions include, for example,
beeswax, hard paraffin, and cetyl alcohol.
[0161] Liquid solutions of the active ingredient in aqueous or oily
solvents may be prepared in substantially the same manner as liquid
suspensions, the primary difference being that the active
ingredient is dissolved, rather than suspended in the solvent.
Liquid solutions of the pharmaceutical composition of the invention
may comprise each of the components described with regard to liquid
suspensions, it being understood that suspending agents will not
necessarily aid dissolution of the active ingredient in the
solvent. Aqueous solvents include, for example, water and isotonic
saline. Oily solvents include, for example, almond oil, oily
esters, ethyl alcohol, vegetable oils such as arachis, olive,
sesame, or coconut oil, fractionated vegetable oils, and mineral
oils such as liquid paraffin.
[0162] A pharmaceutical composition of the invention may also be
prepared, packaged, or sold in the form of oil-in-water emulsion or
a water-in-oil emulsion. The oily phase may be a vegetable oil such
as olive or arachis oil, a mineral oil such as liquid paraffin, or
a combination of these. Such compositions may further comprise one
or more emulsifying agents such as naturally occurring gums such as
gum acacia or gum tragacanth, naturally-occurring phosphatides such
as soybean or lecithin phosphatide, esters or partial esters
derived from combinations of fatty acids and hexitol anhydrides
such as sorbitan monooleate, and condensation products of such
partial esters with ethylene oxide such as polyoxyethylene sorbitan
monooleate. These emulsions may also contain additional ingredients
including, for example, sweetening or flavoring agents.
[0163] As used herein, "parenteral administration" of a
pharmaceutical composition includes any route of administration
characterized by physical breaching of a tissue of a subject and
administration of the pharmaceutical composition through the breach
in the tissue. Parenteral administration thus includes, but is not
limited to, administration of a pharmaceutical composition by
injection of the composition, by application of the composition
through a surgical incision, by application of the composition
through a tissue-penetrating non-surgical wound, and the like. In
particular, parenteral administration is contemplated to include,
but is not limited to, subcutaneous, intraperitoneal,
intramuscular, intrasternal injection, and kidney dialytic infusion
techniques.
[0164] Formulations of a pharmaceutical composition suitable for
parenteral administration comprise the active ingredient combined
with a pharmaceutically acceptable carrier, such as sterile water
or sterile isotonic saline. Such formulations may be prepared,
packaged, or sold in a form suitable for bolus administration or
for continuous administration. Injectable formulations may be
prepared, packaged, or sold in unit dosage form, such as in ampules
or in multi-dose containers containing a preservative. Formulations
for parenteral administration include, but are not limited to,
suspensions, solutions, emulsions in oily or aqueous vehicles,
pastes, and implantable sustained-release or biodegradable
formulations. Such formulations may further comprise one or more
additional ingredients including, but not limited to, suspending,
stabilizing, or dispersing agents. In one embodiment of a
formulation for parenteral administration, the active ingredient is
provided in dry (i.e. powder or granular) form for reconstitution
with a suitable vehicle (e.g. sterile pyrogen-free water) prior to
parenteral administration of the reconstituted composition.
[0165] The pharmaceutical compositions may be prepared, packaged,
or sold in the form of a sterile injectable aqueous or oily
suspension or solution. This suspension or solution may be
formulated according to the known art, and may comprise, in
addition to the active ingredient, additional ingredients such as
the dispersing agents, wetting agents, or suspending agents
described herein. Such sterile injectable formulations may be
prepared using a non-toxic parenterally-acceptable diluent or
solvent, such as water or 1,3-butane diol, for example. Other
acceptable diluents and solvents include, but are not limited to,
Ringer's solution, isotonic sodium chloride solution, and fixed
oils such as synthetic mono- or di-glycerides. Other
parentally-administrable formulations which are useful include
those which comprise the active ingredient in microcrystalline
form, in a liposomal preparation, or as a component of a
biodegradable polymer systems. Compositions for sustained release
or implantation may comprise pharmaceutically acceptable polymeric
or hydrophobic materials such as an emulsion, an ion exchange
resin, a sparingly soluble polymer, or a sparingly soluble
salt.
[0166] Formulations suitable for topical administration include,
but are not limited to, liquid or semi-liquid preparations such as
liniments, lotions, oil-in-water or water-in-oil emulsions such as
creams, ointments or pastes, and solutions or suspensions.
Topically-administrable formulations may, for example, comprise
from about 1% to about 10% (w/w) active ingredient, although the
concentration of the active ingredient may be as high as the
solubility limit of the active ingredient in the solvent.
Formulations for topical administration may further comprise one or
more of the additional ingredients described herein.
[0167] A pharmaceutical composition of the invention may be
prepared, packaged, or sold in a formulation suitable for
ophthalmic administration. Such formulations may, for example, be
in the form of eye drops including, for example, a 0.1-1.0% (w/w)
solution or suspension of the active ingredient in an aqueous or
oily liquid carrier. Such drops may further comprise buffering
agents, salts, or one or more other of the additional ingredients
described herein. Other opthalmically-administrable formulations
which are useful include those which comprise the active ingredient
in microcrystalline form or in a liposomal preparation.
[0168] As used herein, "additional ingredients" include, but are
not limited to, one or more of the following: excipients; surface
active agents; dispersing agents; inert diluents; granulating and
disintegrating agents; binding agents; lubricating agents;
sweetening agents; flavoring agents; coloring agents;
preservatives; physiologically degradable compositions such as
gelatin; aqueous vehicles and solvents; oily vehicles and solvents;
suspending agents; dispersing or wetting agents; emulsifying
agents, demulcents; buffers; salts; thickening agents; fillers;
emulsifying agents; antioxidants; antibiotics; antifungal agents;
stabilizing agents; and pharmaceutically acceptable polymeric or
hydrophobic materials. Other "additional ingredients" which may be
included in the pharmaceutical compositions of the invention are
known in the art and described, for example in Genaro, ed., 1985,
Remington's Pharmaceutical Sciences, Mack Publishing Co., Easton,
Pa., which is incorporated herein by reference.
[0169] Typically, dosages of the compound of the invention which
may be administered to a subject, preferably a human, range in
amount from 1 .mu.g to about 100 g per kilogram of body weight of
the subject. While the precise dosage administered will vary
depending upon any number of factors, including but not limited to,
the type of subject and type of disease state being treated, the
age of the subject and the route of administration. Preferably, the
dosage of the compound will vary from about 1 mg to about 10 g per
kilogram of body weight of the subject. More preferably, the dosage
will vary from about 10 mg to about 1 g per kilogram of body weight
of the subject
[0170] The compound may be administered to a subject as frequently
as several times daily, or it may be administered less frequently,
such as once a day, once a week, once every two weeks, once a
month, or even lees frequently, such as once every several months
or even once a year or less. The frequency of the dose will be
readily apparent to the skilled artisan and will depend upon any
number of factors, such as, but not limited to, the type and
severity of the disease being treated, the type and age of the
subject, etc.
[0171] The invention also includes a kit comprising the composition
of the invention and an instructional material which describes
adventitially administering the composition to a cell or a tissue
of a subject. In another embodiment, this kit comprises a
(preferably sterile) solvent suitable for dissolving or suspending
the composition of the invention prior to administering the
compound to the subject.
[0172] As used herein, an "instructional material" includes a
publication, a recording, a diagram, or any other medium of
expression which can be used to communicate the usefulness of the
peptide of the invention in the kit for effecting alleviation of
the various diseases or disorders recited herein. Optionally, or
alternately, the instructional material may describe one or more
methods of alleviation the diseases or disorders in a cell or a
tissue of a subject. The instructional material of the kit of the
invention may, for example, be affixed to a container which
contains the peptide of the invention or be shipped together with a
container which contains the peptide. Alternatively, the
instructional material may be shipped separately from the container
with the intention that the instructional material and the compound
be used cooperatively by the recipient.
Example I
Methods
[0173] Cell Culture, Plasmid Constructs and Transfection
[0174] The human salivary gland ductal (HSG) cell line was provided
by Matthew Hoffman (NIDCR, Bethesda Md.). HSG cells were cultured
in DMEM/F12 with 10% FBS. Cells were assayed between passage 10 and
20. Some HSG cells were transfected with a SMARTpool of four human
SDC1 (Ambion Inc, Austin Tx) or heparanase-1 or heparanase-2
specific siRNAs at different doses (Dharmacon Inc, Lafayette
Colo.). Other cells were transfected with individual siRNAs also at
different doses. siRNAs sequences are as follows: (i) SDC1 siRNAs,
CGACAAUAAACGGUACUUGTT, GGAGGAAUUCUAUGCCUGA, GGACUUCACCUUUGAAACCTT,
and GGUAAGUUAAGUAAGUUGATT (gene bank accession no:
NM.sub.--002997); SDC2 siRNAs, GGAGUUUUAUGCGUAAAACTT,
GGAUGUAGAGAGUCCAGAGTT, and GGAGUGUAUCCUAUUGAUGTT (gene bank
accession no: NM.sub.--002998); heparanase-1 siRNAs,
GCAAUGAACCUAACAGUUUUU, GAUCAAACCUUGCCACCUUUU,
GGACUGGACUUGAUCUUUGUU, and GAACAGCACCUACUCAAGAUU (gene bank
accession no: NM.sub.--006665). Heparanase-2 siRNA sequences from
Dharmacon were not made publicly available. Also utilized was
Ambion's negative control siRNA #1 (catalogue no. 4611). Silencing
efficiency was evaluated by protein blotting and RT-PCR. HEK293T
cells were purchased from and propagated as suggested by ATCC
(Manassas Va.). HEK293T cells were transfected with a Bgl II
linearized expression vector coding for human SDC1 (hS1-pcDNA3)
using Lipofectamine.TM. 2000 reagent (Invitrogen Life Technologies,
Carlsbad Calif.). Stable populations expressing SDC1 were selected
in culture medium containing 400 ng/ml G418. A human SDC1 deletion
construct lacking 51 amino acids from the N-terminus (`del 1-51`)
was generated from hS1-pcDNA3 by long range reverse PCR using
forward primer 5'-GGTGGTGGATCCACGCAGCTCCTGACGGCTATTCCC-3' and
reverse primer 5'-GGTGGTGGATCCCAGGCTCAGCGCCAGCGCGCACAG-3'
containing BamH1 sites. Amplicons were cut using BamH1, ligated as
plasmid. Human SDC1 `del 51-252` (only N-terminal 50 amino acids of
ectodomain linked to the transmembrane and cytoplasmic domains) was
similarly generated from hS1-pcDNA3 using forward primer
5'-CTAGCTAGCTTGCAAAGCACCTGCACCTG-3' and reverse primer
5'-CTAGCTAGCGAGGTG CTGGGAGGGGTC-3'. This introduced NheI sites 5'
of the codon for Ala51 and 3' of the codon for Glu252 (most
C-terminal ectodomain amino acid). Amplicons were digested with
NheI and ligated as plasmid. Human SDC1 `del 51-310` (only
N-terminal 50 amino acids of ectodomain) N-50 amino acids only was
PCR amplified from hS1-pcDNA3 using forward primer
5'-CTATAGGGAGACCCAAGCTTGGTACCGAG-3' and reverse primer
5'-CCGGAATTCAGCACCTGCACCTGAG-3' containing HindIII and EcoR1 sites.
Amplicons were digested with HindIII and EcoR1 to create cohesive
ends, subsequently purified and ligated into the HindIII/EcoR1 site
of the pcDNA vector. All constructs were confirmed by DNA
sequencing. Plasmids were transfected into HEK293T cells, and
stable or transient transfectants generated. Generation of HEK293T
cells stably transfected with human SDC2 or SDC4 was previously
described (Utani et al., 2001). Development of lacritin-intein
constructs and purification are described elsewhere (Wang et al.,
submitted). A lacritin-GST construct was prepared by subcloning
lacritin cDNA into pGEX4T-2 (Amersham Biosciences, Piscataway N.J.)
using Sap1 and NdeI, in-frame with GST. Recombinant plasmids were
transformed into E. coli strain BL21. Bacterial cultures were
expanded and fusion protein purified on Glutathione-Sepharose 4B
(Amersham Biosciences, Piscataway N.J.). A human SDC1
ectodomain-GST construct was generated from pGEX-2T hS1 ED and
similarly purified.
[0175] Lacritin Affinity Chromatography
[0176] Cell surface biotinylation, and affinity chromatography
followed the method of Chen et al (1997). Briefly, six 150 mm
culture dishes of 80% confluent HSG cells were washed twice on ice
with ice-cold PBS and incubated for 30 min with EZ-Link
Sulfo-NHS-LC Biotin (Pierce, Rockford Ill.). Cells were then washed
twice with PBS-glycine, gently loosened with a cell scraper, and
pelleted at 4.degree. C. The pellet was twice resuspended in 25 ml
PBS-glycine, and incubated for 30 min in 1 ml lysis buffer (50 mM
Tris HCl, pH 7.4, 100 mM NaCl, 5 mM MnCl.sub.2, 2 mM PMSF, 200 mM
n-octyl-.beta.-D-glucopyranoside, and protease inhibitors (Roche
Diagnostics, Penzberg Germany)). Lysate was centrifuged for 15 min
at 4.degree. C., and the supernatant applied to a 1 ml pre-column
then washed through with 1 ml of binding buffer (50 mM Tris HCl, pH
7.4, 100 mM NaCl, 5 mM MnCl.sub.2, 2 mM PMSF, 50 mM
n-octyl-.beta.-D-glucopyranoside) and collected. Half was applied
to a lacritin-intein column in which lacritin was coupled to chitin
beads via chitin-binding intein, and the other half to a negative
control column that included an approximately equivalent molar
amount of intein-chitin only. Columns were rotated end-to-end
overnight at 4.degree. C., then each was washed with 20 column
volumes of affinity column buffer and eluted with the same buffer
containing 1 M NaCl. Twenty 100 .mu.L fractions were collected per
column. Fractions were run on 8% SDS-PAGE gels, and silver stained
or transferred to nitrocellulose for blotting with streptavidin
peroxidase. For the latter, blots were blocked with PBS containing
0.1% Tween-20 and 2.5% milk for 1 h at 37.degree. C., washed three
times with PBS/0.1% Tween-20, incubated in 50 ml of 1:1000
streptavidin-horseradish peroxidase conjugate (Amersham
Biosciences, Piscataway N.J.) in PBS/0.1% Tween-20, washed five
times with the same buffer and then detected using ECL reagent
(Pierce, Rockford Ill.). Bands of interest were excised and
sequenced by mass spectroscopy (Biomolecular Research Facility,
University of Virginia).
[0177] Affinity Precipitation Binding
[0178] Human SDC1, SDC2, or SDC4 stably-expressing HEK293T cells
were harvested on ice into 1 ml of the same lysis buffer used for
affinity chromatography. Lysates were cleared by centrifugation
(20,000.times.g) at 4.degree. C., and protein concentration of
supernatant was estimated by the BCA assay (Pierce, Rockford Ill.).
Lacritin-intein or lacritin-GST (5 .mu.g) and FGF2-GST fusion
proteins were respectively bound to chitin beads (New England
Biolabs, Ipswich Mass.) or glutathione-Sepharose beads (Amersham
Biosciences, Piscataway N.J.). Beads were incubated with lysates
(.about.200 .mu.g of SDC1 stably expressing HEK293T cells)
overnight at 4.quadrature.C., and washed three times with binding
buffer as above (each wash three times the bead volume). In
competition assays, SDC1 lysates were mixed with increasing amounts
of soluble lacritin, HS, HS plus CS (Seikagaku America, Falmouth
Mass.), bacterially expressed human SDC1 ectodomain (hS1 ED),
native SDC2, native SDC4, N-24 or C-25. Mixtures were then applied
to lacritin immobilized beads, and further studied as described
below. For sequential pull down assays, cell lysates were
sequentially affinity precipitated with FGF2-GST or
lacritin-intein. After FGF2-GST depletion of all available
FGF-bindable SDC1, one-half was precipitated with lacritin-intein.
The other half was methanol precipitated overnight and resuspended
in heparitinase buffer. Similarly, after lacritin-intein depletion
of all available lacritin-bindable SDC1, one-half was precipitated
with FGF2-GST and the other half precipitated by methanol
overnight, then resuspended in heparitinase buffer. The reactions
were separated by SDS-PAGE, and blotted using anti-SDC1 mAb B-B4
(Serotec, Oxford UK) or anti-SDC2 polyclonal antibody L-18 or
anti-SDC4 polyclonal antibody N-19 (Santa Cruz Biotechnology, Santa
Cruz Calif.) followed by ECL detection (Pierce, Rockford Ill.).
[0179] For SDS-PAGE and immunoblotting, beads were digested with
heparitinase I (Seikagaku America, Falmouth Mass.) and chondroitin
ABC lyase (MP Biochemicals, Aurora Ohio) since native syndecans
migrate as a heterodisperse smear in SDS-PAGE. Briefly, beads were
resuspended in heparitinase buffer (50 mM Hepes, pH 6.5, 50 mM
NaOAc, 150 mM NaCl, 5 mM CaCl.sub.2) with 0.0001 units heparitinase
and 0.005 units chondroitin ABC lyase for 2 h at 37.degree. C. A
second aliquot of each enzymes was added for an additional 2 h.
Samples were diluted with 2.times. sample buffer, separated by 10%
SDS-PAGE, transferred to Immobilon-P PVDF (Millipore, Billerica,
Mass.) for 4 h at 300 mA, fixed for 30 min in PBS containing 0.05%
glutaraldehyde (Sigma, Saint Louis Mo.), and blocked overnight at
4.degree. C. in TBS (10 mM Tris, 150 mM NaCl, pH 7.4) with 3% BSA.
mAb B-B4 diluted in blocking buffer was incubated with blots for 2
h at RT, washed five times with 10 mM Tris, 150 mM NaCl, pH 7.4
containing 0.1% Tween-20 and detected with alkaline-phosphatase
conjugated secondary antibody (Amersham Biosciences, Piscataway
N.J.) using ECL.
[0180] Heparanase Detection
[0181] For analysis, cellular heparanase was enriched by HiTrap
heparin affinity purification (Amersham Biosciences, Piscataway
N.J.). Briefly, HSG or HEK293 lysates were dialyzed overnight
against binding buffer (10 mM sodium phosphate, pH 7) and applied
to the column. After washing with 10 column volumes of binding
buffer, heparanase was eluted using 5 column volumes of elution
buffer (10 mM sodium phosphate, 2 M NaCl, pH 7). Protein
concentration was determined by BCA and analyzed by 10% SDS-PAGE.
Heparanase-1 was detected with rabbit polyclonal antibodies
directed against human heparanase (kindly provided by Israel
Vlodaysky, Rappaport Faculty of Medicine, Haifa, Israel) followed
by HRP-conjugated secondary antibody and ECL.
[0182] Mitogenesis Assay
[0183] HSG cells in serum-containing media were seeded in 24-well
plates at a density of 0.5.times.10.sup.5 cells/well. After 24 h,
the medium was changed to Minimum Essential Medium Alpha
Modification with washes for 24 h, then lacritin was added for 24 h
to a final concentration of 10 nM in the same medium containing
[3H]-thymidine (2 .mu.Ci/ml). Cells were incubated alone with
lacritin or together with increasing amount of bacterial-expressed
human SDC1 ectodomain (hS1 ED) as a soluble inhibitor. Cells
depleted of heparanase-1 or SDC1 were treated with lacritin in
[3H]-thymidine 48 h after siRNA transfection. To rescue heparanase
depleted cells, .about.1 .mu.g heparanase enriched from HSG or
HEK293 cells using heparin affinity column or 0.0001 units
bacterial heparitinase (Seikagaku America) was added together with
lacritin and [3H]-thymidine for 24 h. [3H]-thymidine incorporation
was stopped by placing on ice. Cultures were washed twice with
ice-cold PBS, fixed with cold and then RT TCA (10%) for 10 min
each, washed twice with RT PBS, collected in 1 N NaOH, neutralized
with 1 N HCl, and then transferred to liquid scintillation vials
for measurement.
[0184] HS Chain Analysis
[0185] 50% confluent HSG cell cultures in 150-mm culture dishes
were metabolically labeled with 50 .mu.Ci/ml Na235SO.sub.4 (1494
Ci/mmol; PerkinElmer, Boston Mass.) in DMEM for 48 h as described
by Zako et al. (2003). Both normal and heparanase-1 depleted cells
were labeled. After washing three times with PBS, cell lysates were
collected and affinity precipitated with FGF2-GST or
lacritin-intein overnight at 4.degree. C. SDC1 bound to beads was
digested with chondroitin ABC lyase (MP Biochemicals, Aurora Ohio)
for 3 h at 37.degree. C., eluted with 2 M NaCl and then subjected
to eliminative cleavage and reduction of HS by adjusting to 100 mM
NaOH/1 M NaBH.sub.4 for 24 h at 37.degree. C. Released HS was
neutralized by drop wise addition of 1M HCl and subjected to
Sepharose CL-6B column (1.times.57 cm) gel filtration
chromatography in PBS at a flow rate 16 ml/h. Radioactivity was
measured by liquid scintillation counting. The void volume (V0,
fraction 26) and total column volume (Vt, fraction 62) were
respectively determined using dextran blue and sodium dichromate as
markers.
[0186] Other Methods--Other methods useful in the present invention
are described in PCT Publication PCT/US0225/016112 (WO 2005/119899)
and in U.S. patent application Ser. No. 10/468,372.
[0187] Results:
[0188] Lacritin Targets Cell Surface SDC1
[0189] Lacritin promotes epithelial proliferation at low nanomolar
levels, suggesting a cell surface binding K.sub.d in the nanomolar
range sufficient for affinity purification of its receptor. An
apparent 190 kDa cell surface protein eluted from lacritin, but not
control, columns after incubation with detergent lysates of surface
biotinylated human salivary ductal (HSG) cells in buffer containing
physiological levels of salt (FIG. 1). Sequencing identified the
190 kDa protein as a multimer of human SDC1, a transmembrane
proteoglycan that acts as a co-receptor for mitogenic signaling by
binding heparin-binding growth factors such as FGFs, HGFs, Wnts,
Hhs, and HGFs via its HS glycosaminoglycan chains (Alexander et
al., 2000; Esko and Selleck, 2002).
[0190] To assess this interaction by affinity precipitation, we
created a 293T cell line stably expressing human SDC1, and treated
lacritin or positive control FGF2 precipitates with bacterial
heparitinase and chondroitinase to remove the large and
heterogenous glycosaminoglycan chains. The supernatant and pellet
of the digest were then separately blotted for SDC1 using mAb B-B4
directed against the core protein. This revealed 190 and 80 kDa
bands, confirming the multimeric nature of the 190 kDa SDC1 band
(FIG. 2A). Lacritin-bound SDC1 was consistently detected in the
pellet, implying that the ligation was not solubilized by
heparitinase/chondroitinase digestion and therefore may involve the
core protein. In keeping with this possibility, lacritin did not
target SDC2 or SDC4 (FIG. 2C) that share HS chains but only 27-28%
ectodomain identity with SDC1. FGF2 as expected bound all three
syndecans via heparitinase cleavable HS (FIG. 2B, C).
[0191] SDC1 Binding Via a Lacritin C-Terminal Domain
[0192] Lacritin truncation analysis recently identified a
C-terminal mitogenic domain capable of forming an amphipathic alpha
helix as per the receptor binding domain of PTHLP (Wang et al.,
2006). Could SDC1 binding and mitogenic sites be shared? SDC1
binding was unaffected by deletion (FIG. 3A) of five and ten amino
acids from the C-terminus (FIG. 3B), or fifteen and twenty-four
amino acids from the N-terminus (FIG. 3C) of lacritin. However,
affinity was substantially diminished after five more C-terminal
amino acids were deleted (C-15) and completely abolished from C-25
and C-49 lacritin (FIG. 3B). These data point to a binding site
between amino acids 100 and 109 of mature lacritin that mirrors the
mitogenic domain. To validate and further probe this observation,
lacritin-SDC1 affinity precipitations were competitively challenged
with the truncated lacritin mutants (FIG. 4). Soluble lacritin and
N-24, but not C-25 and C-59 inhibited binding. Also inhibitory was
recombinant human SDC1 core protein (hS1 ED) expressed in E. coli,
but not HS, CS nor human SDC2 or SDC4. Taken together, these data
suggest that ligation of SDC1 is specified by a region within
lacritin's C-terminus that appears to show affinity for SDC1's core
protein but not HS or CS.
[0193] SDC1 is Required for Lacritin Mitogenesis
[0194] Since mitogenic (Wang et al, submitted) and SDC1 binding
domains map to the same ten amino acid region, we questioned
whether competition with recombinant hS1ED would disrupt
lacritin-dependent mitogenesis. Soluble hS1 ED inhibited
proliferation of lacritin-stimulated HSG cells in a dose-dependent
manner. The same inhibitory doses had no effect on C-25 treated
cells nor on FBS stimulated proliferation (FIG. 5A). To approach
this question differently, HSG cells were depleted of SDC1 by siRNA
(FIG. 5C). Dose-dependent depletion of SDC1, but not depletion of
SDC2 (FIG. 5C), completely abrogated lacritin mitogenic
responsiveness (FIG. 5B). Lacritin signals through G.alpha.i or
G.alpha.o/PKC.alpha.-PLC/Ca2+/calineurin/NFATC1/COX-2 toward
mitogenesis (Wang et al, submitted). We therefore examined COX-2
expression in SDC1 and SDC2 depleted cells. In SDC1, but not SDC2,
knockdown cells lacritin-dependent COX-2 expression was absent
(FIG. 5D). Ligation of SDC1 thus appears to be a required upstream
step in lacritin mitogenic signaling.
[0195] Lacritin and FGF2 Target Different Forms of SDC1
[0196] We noted how biotinylated SDC1 from surface-labeled HSG
cells was selectively purified on lacritin affinity columns and
that it migrated as a relatively distinct band (FIG. 1) without
prior heparitinase/chondroitinase to excise the heterogenous HS and
CS chains. In contrast, native SDC1 without digestion presents as a
broad smear (FIG. 10). Also, lacritin affinity precipitated SDC1
was retained in the pellet after heparitinase/chondroitinase
digestion. Could the sharply defined 190 and 80 kDa bands represent
a minor deglycanated or hypoglycosylated form preferentially
enriched because of lacritin's apparent core protein-related
affinity? To explore this possibility, we sequentially depleted
either FGF2- or lacritin-bindable SDC1 from lysates then challenged
the depleted lysates respectively with lacritin or FGF2 affinity
precipitation (FIG. 6). Affinity precipitates were treated with
heparitinase/chondroitinase prior to SDS-PAGE to simplify mAb B-B4
detection of the core protein in the digest supernatant (FGF2) or
pellet (lacritin). Successive pull-down with FGF2-GST depleted all
FGF2-bindable SDC1 (FIG. 6A, lanes 1-3). Interestingly, the amount
of SDC1 available to interact with lacritin-intein was unaffected
(FIG. 6A, lane 4 versus lanes 1 and 9). Similarly, depletion of
SDC1 with lacritin-intein slightly but not substantially diminished
SDC1 binding to FGF2-GST (FIG. 6A, lanes 5-7 versus lanes 8 and
10). This implies that two pools of SDC1 may be available. One is
apparently native SDC1, to which lacritin appears to lack affinity.
The other may be an HS-free or partially deglycanated form of SDC1.
Could the latter be an immature intracellular form? This appears
not to be the case. When cells were gently trypsinized prior to
lysis, no lacritin-bindable SDC1 was detected (FIG. 6B) in keeping
with the original purification of labeled SDC1 from surface
biotinylated cells (FIG. 1). Also ruled out was bacterial
heparitinase contamination of recombinant lacritin.
[0197] We took advantage of 3G10 mAb directed against a desaturated
uronate epitope generated by heparitinase digestion (David et al.,
1992) and could detect lacritin-bound SDC1 only after treatment
with exogenous heparitinase (FIG. 6C). That heparitinase can create
the 3G10 epitope is revealing, for it points to the presence of HS
or HS stubs on the core protein that is recognized by lacritin. HS
stubs could be generated by heparanase, a eukaryotic
endo-.beta.-D-glucuronidase that cleaves the entire HS chains
between GlcUA and GlcNAc linkages. Taken together these data
suggest that lacritin and FGF2 target different forms of cell
surface SDC1. SDC1 bound by lacritin is less heterogenous,
suggesting that although it is decorated with sufficient HS to be
recognized by heparitinase, much of its HS has been removed.
[0198] Heparanase-Dependent Lacritin Mitogenesis
[0199] One hypothesis to explain these data is that
heparanase-sensitive HS sterically blocks lacritin binding to a
latent core protein site in native SDC1. If this is true,
heparitinase digestion of native SDC1 should promote lacritin
binding (FIG. 7A). To study this possibility, SDC1 from cell
lysates was purified on FGF2-GST, washed, salt eluted, heparitinase
digested, and then incubated with lacritin-intein (lane 1, 0.5 M
NaCl eluate; lane 2, 1.0 M NaCl eluate). As controls, SDC2 and SDC4
from cell lysates were individually purified on FGF2-GST, washed,
salt eluted, heparitinase digested, and then also incubated with
lacritin-intein (SCD2: lane 3, 0.5 M NaCl eluate; lane 4, 1.0 M
NaCl eluate; and SCD4: lane 5, 0.5 M NaCl eluate; lane 6, 1.0 M
NaCl eluate). Affinity precipitates were
heparitinase/chondroitinase (+) treated prior to SDS-PAGE and
blotting for SDC1, SDC2 or SDC4. We observe that FGF2-purified
SDC1, but not FGF2-purified SDC2 or SDC4, can indeed bind lacritin
after heparitinase treatment (FIG. 7A, lanes 1, 2), presumably by
exposing a hidden site.
[0200] Where does lacritin bind? Steric hindrance by the N-terminal
HS chains suggests that lacritin may bind SDC1's N-terminus.
However binding might occur elsewhere when consideration is given
to HS chain length and core protein folding. To examine these
possibilities, we generated cell lines stably or transiently
expressing human SDC1 lacking 51 N-terminal amino acids (`del
1-51`), or lacking amino acids 51-252 of the ectodomain (`del
51-252`), or retaining only the N-terminal 50 amino acids as a
secreted form (`del 51-310`) (FIG. 7B). Del 51-252 and del 51-310
both bound lacritin, but not del 1-51 (FIG. 7C, D), suggesting that
SDC1's N-terminus is recognized by lacritin.
[0201] Although most heparanase is associated with endocytic
compartments, the argument for an active cell surface role is
compelling. Evidence includes heparanase secretion by activated
endothelial (Chen et al., 2004) and T cells during inflammation
(Fridman et al., 1987), antisense-inhibited cancer dissemination
(Uno et al., 2001), and overexpression-associated migration of hair
stem cell progeny (Zcharia et al., 2005). Is heparanase required
for lacritin mitogenic binding of SDC1? Blotting for heparanase-1
detected the active 50 kDa form that was enrichable on a HiTrap
heparin column from both HSG and HEK293/SDC1 lysates (FIG. 8A), in
keeping with the known affinity of heparanase for heparin. The
presence of heparanase in these fractions was confirmed in
preliminary activity assays showing digestion of
.sup.35SO.sub.4-labeled matrix (not shown). To assess whether
heparanase-1 or -2 is required for lacritin-dependent
proliferation, we treated HSG cells with siRNAs for each (FIG. 8B,
C). Heparanase-1 is abundantly expressed and when knocked-down
reduced lacritin-dependent proliferation to background in a dose
dependent manner. Importantly, the lowest effective doses did not
affect EGF-dependent mitogenesis and depleted cells were rescued by
addition of exogenous heparanase or heparitinase (FIG. 8C). In
depleted cells without lacritin, neither had any effect (FIG. S2),
thus eliminating the possibility that rescue was instead from
heparanase signaling (Gingis-Velitsky et al., 2004). Heparanase-2
siRNA also had no effect (FIG. 8C) but standard RT-PCR failed to
detect heparanase-2 expression in untreated cells (not shown) in
keeping with real time PCR detection of <15 mRNA copies/ng cDNA
in human salivary gland (McKenzie et al., 2000). Above we noted
that lacritin mitogenic signaling promotes COX-2 expression
downstream of NFATC1 (Wang et al, submitted), and that siRNA
depletion of SDC1, but not SDC2, abrogates lacritin-dependent COX-2
expression (FIG. 5D). If heparanase-1 is functionally linked with
SDC1 in lacritin mitogenic signaling, then depletion of
heparanase-1 should have a similar effect. We observe in FIG. 5D
that this is indeed the case. Lacritin has no effect on COX-2
expression in cells lacking heparanase-1.
[0202] Thus, it is apparent that two pools of SDC1 are available,
and that the lacritin-bindable pool is likely generated by
heparanase. If this is true, the distribution of HS chain sizes in
the FGF2-bindable vs lacritin-bindable pools should differ. To
explore this possibility, each pool was isolated by affinity
precipitation from .sup.35SO.sub.4-labeled cell lysates. After
chondroitinase digestion, and then elution with salt, HS was
cleaved from the core protein with NaBH4 and analyzed by CL-6B gel
filtration chromatography (FIG. 8D). In contrast to unimodal HS
from the FGF2 pool (Kav=0.3-0.33; .about.40 kDa), HS from the
lacritin pool was bimodal with most .sup.35SO.sub.4 eluting with a
Kav of 0.75-0.8. This corresponds to approximately 4-5 kDa. Both
estimates are based on Waterson's standard curve (Waterson, 1971).
Interestingly, lower molecular weight HS was eliminated by
heparanase-1 depletion (FIG. 8D). Taken together, these data
suggest a mechanism whereby SDC1's HS-rich N-terminus is partially
deglycanated by heparanase-1 to facilitate lacritin binding and
signaling to mitogenic COX-2.
Discussion
[0203] How cell surface proteoglycans specify regions of epithelial
morphogenesis, homeostasis or secretion is a central question in
developmental biology. We report a new mechanism in which the
N-terminal deglycanated core protein of SDC1 and not complete HS/CS
chains nor SDC2 or SDC4, appears to target the epithelial selective
prosecretory mitogen lacritin. An important and novel step in this
approach is that binding necessitates prior complete or partial
removal of HS chains by endogenous heparanase. Limiting lacritin
activity to specific sites of secreted heparanase thus transforms
widely expressed SDC1 into a regulated surface binding protein.
[0204] Recent studies emphasize a growing appreciation for an
interaction role of syndecan core proteins beyond the binding
accomplished by their HS chains. Sdc1 regulates the activation of
the .alpha.v.beta.3 and .alpha.v.beta.5 integrins in several cell
types, an interaction that depends on functional coupling between
an extracellular active site in the syndecan core protein and the
integrins (Beauvais and Rapraeger, 2003; Beauvais et al., 2004;
McQuade et al, 2006). HS plus a short extracellular hydrophobic
region near the transmembrane domain of mouse Sdc1 inhibits ARH-77
human B lymphoid cell invasion into collagen I (Langford et al.,
2005). Recombinant human SDC2 core protein from E. coli mediates
adhesion and proliferation of colon carcinoma cells (Park et al.,
2002), and mouse Sdc4 contains a high affinity cell-binding domain
proximal to HS attachment sites (McFall and Rapraeger, 1997, 1998).
Thus, the ectodomains of syndecan core proteins mediate a number of
morphogenetic and homeostatic events.
[0205] Lactitin's preference for heparanase-deglycanated SDC1 core
protein is an interesting cell targeting strategy that successfully
appropriates a ubiquitous proteoglycan for a role as a restrictive
cell surface binding protein. That this is feasible is a reflection
of the rarity of SDC1 as a part-time or hypoglycosylated
proteoglycan and the lack of general ectodomain sequence
conservation among syndecans. Focal heparanase release may regulate
lacritin's mitogenic and prosecretory activity with unusual
accuracy. Focal heparanase degradation of cell surface and
extracellular matrix HS is implicated in glandular morphogenesis
(Zcharia et al., 2004), stem cell migration (Zcharia et al., 2005)
and cell survival (Cohen et al., 2005). It also plays a central
role in inflammation and cancer (Reiland et al., 2004). Activated
endothelial (Chen et al., 2004) and T cells secrete heparanase
during inflammation (Fridman et al., 1987). Up-regulation of
heparanase mRNA is correlated with reduced HS in invasive
esophageal carcinomas (Mikami et al., 2001), whereas the opposite
is linked to an increase in overall HS in differentiating myoblasts
(Barbosa et al., 2005). Our studies did not address whether SDC2
and SDC4 are functional targets of heparanase. Neither bound
lacritin with or without prior heparitinase treatment. Nonetheless,
exploration of other ligands may reveal a similar capacity for
latency in these and other HS proteoglycans.
[0206] Heparanase-regulated proliferation has previously been
attributed to the release of HS-bound FGFs in metastatic breast
cancer (Kato et al., 1998). Notably, the first lacritin EST in
GenBank derives from a subtracted breast cancer library and
evidence has been presented for lacritin gene amplification in some
metastatic breast cancers (Porter et al., 2003). Others have
proposed that lacritin is the second most frequent SAGE marker for
circulating breast cancer cells (Bosma et al., 2002). Sdc1 is
required for Wnt-dependent breast cancer in mice (Alexander et al.,
2000), and in human cancers is upregulated in some but not others
coincident with a role in early proliferative events (Ding et al.,
2005). Thus, lacritin, heparanase, and SDC1 together potentially
offer a new paradigm for some human breast cancers.
[0207] Although the sequencing data did not expose lacritin's
putative signaling receptor, use of pharmacological inhibitors and
siRNA have identified proximal signaling elements as G.alpha.i or
G.alpha.o/PKC.alpha.-PLC/Ca2+/calcineurin/NFATC1/COX-2 and
G.alpha.i or G.alpha.o/PKC.alpha.-PLC/PLD1/mTOR (Wang et al.,
submitted). Both are ERK1 and ERK2-independent and thus contrast
with SDC1 cytoskeletal signaling. Lacritin signaling may thus
involve a G-protein coupled receptor or G-protein dependent ion
channel that gains ligand affinity as a consequence of lacritin
immobilization on SDC1. Possibly core protein binding may be
stabilized by interaction with HS stubs detected in the lower
molecular weight heparanase-dependent peak (FIG. 8D).
Interestingly, since lacritin- and FGF2-bindable SDC1 pools share
some HS chains of similar size, not all HS on lacritin-bound SDC1
seem to be cleaved. Lack of complete competition of soluble
lacritin for SDC1 in lacritin affinity precipitation assays vs N-24
might hypothetically result from folding of lacritin's more
negatively charged N-terminus onto its positively charge
C-terminus. Cleavage of HS by heparanase to generate
lacritin-dependent mitogenic activity offers a novel mechanism of
epithelial renewal with important implications to the physiology of
human exocrine glands.
[0208] Taken together, these observations contribute to the growing
appreciation of mechanisms by which extracellular enzymes regulate
proteoglycan activity in unexpected ways. Recently described Sulf1
and Sulf2 modify the character of HS chains by selectively removing
certain 6-O-sulfate groups thus altering growth factor signaling
and tumor growth (Dai et al., 2005). Heparanase cleavage of HS
promotes angiogenesis by solubilizing HS-bound growth factors
(Sanderson et al., 2004). This new discovery that heparanase
removal of HS chains removes a block to mitogenic signaling offers
a new regulatory paradigm.
Example II
[0209] Heparanase is an `on` switch for lacritin binding to
syndecan-1 (FIG. 12A; Ma et al, '06) that in turn appears to
facilitate activation of a receptor. The receptor has the signaling
characteristics of a G.alpha.i or G.alpha.o coupled receptor (GPCR;
Wang et al, '06). For heparanase to play such a central role in
lacritin cell targeting, one might expect heparanase to be a normal
constituent of human tears. To the best of our knowledge heparanase
has not been reported in tears. Collaborator Leslie Olsakovsky (UVa
Ophthalmology) collected tears from normals and patients suffering
from dry eye (mostly non-Sjogren's). Western blots of equal protein
loads of 30 tear samples from normals vs dry eye patients suggest
that heparanase is a normal tear constituent (see example blot FIG.
12B) and is substantially reduced in dry eye tears. Interestingly
lacritin, UTP and ATP stimulate heparanase release (FIG. 12C). The
65 kDa form detected is the latent pro-survival form. Heparanase
becomes active upon processing to 50 kDa, a form that can be
detected with this antibody (Ma et al, '06). We suspect that
availability of active heparanase is transient, as per the lacritin
`off/on` switch mechanism. The Inspire Pharmaceutical product
INS365 for dry eye is a UTP analogue. Latent heparanase is
constitutively expressed by all layers of the normal corneal
epithelium in mice (Berk et al, '04). Heparanase has been
implicated in glandular morphogenesis, epidermal stem cell
migration and cell survival.
[0210] Lacritin N-24 Partially Inhibits 125I-Iodoclonidine Binding
to the Alpha-2C Adrenergic Receptor. FGF2 displays low affinity
binding to FGFR1 with affinity enhanced by coincident binding to
syndecan-1, heparin or heparan sulfate. If we are correct that
syndecan-1 increases lacritin's affinity for a G-protein coupled
receptor (GPCR), possibly some low affinity GPCR binding can be
detected without syndecan-1 in low salt. To ask this question, a
low salt screen of 31 immobilized human GPCRs in which 10 nM
lacritin, N-24 or C-25 were asked to compete with 125I-receptor
ligand for receptor binding. Cutoff is 50% inhibition. N-24
lacritin (64%), but not intact lacritin (29%) or inactive C-25
(15%), competed for binding to the alpha-2C-adrenergic (ADRA2C)
receptor with an equilibrium dissociation constant (Ki) of
1289.+-.121 nM in repeated assays (FIG. 13). Although preliminary,
this compares to 1698 nM for native agonist epinephrine. Possibly
N-24's lack of seven negatively charged residues may improve
binding in the absence of syndecan-1.
[0211] We depleted ADRA2C by transfecting with 10 nM pooled or
individual siRNAs to ADRA2C (FIG. 14). Pooled siRNAs D1-D4 reduced
lacritin responsiveness below baseline. We then transfected
individual or D1-3 pooled siRNAs. D3 and D1-3 reduced the
lacritin-dependent mitogenesis by almost 50%, whereas D1 and D4
were less effective. Individual siRNAs had no effect on
FBS-stimulated mitogenesis (not shown). ADRA2C is G.alpha.i or
G.alpha.o coupled (pertussis toxin sensitive) and expressed by
normal human conjunctival (Diebold et al, '05) and corneal (Huang
et al, '95) epithelia. ADRA2C is best known as a neural receptor
involved in the regulation of sympathetic neurotransmitter release.
Little is known of its role on epithelial cells.
[0212] Lacritin N-Terminal Deletion Analysis Suggests a Putative
Signaling Receptor Binding Site. Syndecan-1 binds lacritin's
C-terminus (Ma et al, '06). Where might the hypothetical signaling
receptor bind? A series of lacritin N-terminal deletion mutants
were developed, expressed and purified by our JMU collaborators.
Subconfluent HCE-T cells in serum-free medium were treated with
each in our standard 3H-thymidine mitogenesis assay. N-24, N-35,
N-45, N-55, N-65 and lacritin are all mitogenic. Activity is lost
when the amino acids KSIVEK are removed from N-65. PeptideStructure
and HelicalWheel analyses implicate this region as another
amphipathic .alpha.-helix. Interestingly, the lacritin alternative
splice form `lacritin-b` lacks the sequence SIVEKSILLTE (Ma et al,
'07), and alternative splice form `lacritin-c` has a completely
novel C-terminus, lacking both this site and the syndecan-1 binding
site. This suggests that lacritin-b and -c would be inactive.
[0213] Discovery of Lacritins in Lower Species: Conservation of Two
Binding Motifs. New public genomic sequencing (Sanger Institute
Ensembl website) has recently revealed a number of novel lower
species lacritins. Putative lacritin orthologues were detected in
armadillo, domestic cat, lesser hedgehog, microbat, tree shrew and
common shrew. We expect this list to expand as more species are
sequenced to completion. We extracted each sequence then
constructed a Phylogram using GrowTree (not shown). Chimp and tree
shrew lacritins are respectively the most and least identical to
human lacritin. We also aligned each using ClustralW+. Interesting
regions of conservation include KSIVEK and the C-terminal
syndecan-1 binding site (not shown). We performed helical wheel
analysis on sequences from the latter. The putative amphipathic
.alpha.-helix (Wang et al, '06) appears to be conserved in all
species and thus most may be capable of binding syndecan-1, as per
human lacritin (Ma et al, '06).
[0214] Headings are included herein for reference and to aid in
locating certain sections. These headings are not intended to limit
the scope of the concepts described therein under, and these
concepts may have applicability in other sections throughout the
entire specification.
[0215] The disclosures of each and every patent, patent
application, and publication cited herein are hereby incorporated
herein by reference in their entirety.
[0216] While this invention has been disclosed with reference to
specific embodiments, it is apparent that other embodiments and
variations of this invention may be devised by others skilled in
the art without departing from the true spirit and scope of the
invention.
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Sequence CWU 1
1
2216PRTHomo sapiens 1Lys Ser Ile Val Glu Lys1 5221DNAArtificial
SequenceA synthetic siRNA 2cgacaauaaa cgguacuugt t 21319RNAHomo
sapiens 3ggaggaauuc uaugccuga 194138PRTHomo sapiens 4Met Lys Phe
Thr Thr Leu Leu Phe Leu Ala Ala Val Ala Gly Ala Leu1 5 10 15Val Tyr
Ala Glu Asp Ala Ser Ser Asp Ser Thr Gly Ala Asp Pro Ala 20 25 30Gln
Glu Ala Gly Thr Ser Lys Pro Asn Glu Glu Ile Ser Gly Pro Ala 35 40
45Glu Pro Ala Ser Pro Pro Glu Thr Thr Thr Thr Ala Gln Glu Thr Ser
50 55 60Ala Ala Ala Val Gln Gly Thr Ala Lys Val Thr Ser Ser Arg Gln
Glu65 70 75 80Leu Asn Pro Leu Lys Ser Ile Val Glu Lys Ser Ile Leu
Leu Thr Glu 85 90 95Gln Ala Leu Ala Lys Ala Gly Lys Gly Met His Gly
Gly Val Pro Gly 100 105 110Gly Lys Gln Phe Ile Glu Asn Gly Ser Glu
Phe Ala Gln Lys Leu Leu 115 120 125Lys Lys Phe Ser Leu Leu Lys Pro
Trp Ala 130 135521DNAArtificial SequenceA synthetic siRNA
5ggacuucacc uuugaaacct t 21621DNAArtificial SequenceA synthetic
siRNA 6gguaaguuaa guaaguugat t 21721DNAArtificial SequenceA
synthetic siRNA 7ggaguuuuau gcguaaaact t 21821DNAArtificial
SequenceA synthetic siRNA 8ggauguagag aguccagagt t
21921DNAArtificial SequenceA synthetic siRNA 9ggaguguauc cuauugaugt
t 211021RNAArtificial SequenceA synthetic siRNA 10gcaaugaacc
uaacaguuuu u 211121RNAArtificial SequenceA synthetic siRNA
11gaucaaaccu ugccaccuuu u 2112310PRTHomo sapiens 12Met Arg Arg Ala
Ala Leu Trp Leu Trp Leu Cys Ala Leu Ala Leu Ser1 5 10 15Leu Gln Pro
Ala Leu Pro Gln Ile Val Ala Thr Asn Leu Pro Pro Glu 20 25 30Asp Gln
Asp Gly Ser Gly Asp Asp Ser Asp Asn Phe Ser Gly Ser Gly 35 40 45Ala
Gly Ala Leu Gln Asp Ile Thr Leu Ser Gln Gln Thr Pro Ser Thr 50 55
60Trp Lys Asp Thr Gln Leu Leu Thr Ala Ile Pro Thr Ser Pro Glu Pro65
70 75 80Thr Gly Leu Glu Ala Thr Ala Ala Ser Thr Ser Thr Leu Pro Ala
Gly 85 90 95Glu Gly Pro Lys Glu Gly Glu Ala Val Val Leu Pro Glu Val
Glu Pro 100 105 110Gly Leu Thr Ala Arg Glu Gln Glu Ala Thr Pro Arg
Pro Arg Glu Thr 115 120 125Thr Gln Leu Pro Thr Thr His Gln Ala Ser
Thr Thr Thr Ala Thr Thr 130 135 140Ala Gln Glu Pro Ala Thr Ser His
Pro His Arg Asp Met Gln Pro Gly145 150 155 160His His Glu Thr Ser
Thr Pro Ala Gly Pro Ser Gln Ala Asp Leu His 165 170 175Thr Pro His
Thr Glu Asp Gly Gly Pro Ser Ala Thr Glu Arg Ala Ala 180 185 190Glu
Asp Gly Ala Ser Ser Gln Leu Pro Ala Ala Glu Gly Ser Gly Glu 195 200
205Gln Asp Phe Thr Phe Glu Thr Ser Gly Glu Asn Thr Ala Val Val Ala
210 215 220Val Glu Pro Asp Arg Arg Asn Gln Ser Pro Val Asp Gln Gly
Ala Thr225 230 235 240Gly Ala Ser Gln Gly Leu Leu Asp Arg Lys Glu
Val Leu Gly Gly Val 245 250 255Ile Ala Gly Gly Leu Val Gly Leu Ile
Phe Ala Val Cys Leu Val Gly 260 265 270Phe Met Leu Tyr Arg Met Lys
Lys Lys Asp Glu Gly Ser Tyr Ser Leu 275 280 285Glu Glu Pro Lys Gln
Ala Asn Gly Gly Ala Tyr Gln Lys Pro Thr Lys 290 295 300Gln Glu Glu
Phe Tyr Ala305 31013543PRTHomo sapiens 13Met Leu Leu Arg Ser Lys
Pro Ala Leu Pro Pro Pro Leu Met Leu Leu1 5 10 15Leu Leu Gly Pro Leu
Gly Pro Leu Ser Pro Gly Ala Leu Pro Arg Pro 20 25 30Ala Gln Ala Gln
Asp Val Val Asp Leu Asp Phe Phe Thr Gln Glu Pro 35 40 45Leu His Leu
Val Ser Pro Ser Phe Leu Ser Val Thr Ile Asp Ala Asn 50 55 60Leu Ala
Thr Asp Pro Arg Phe Leu Ile Leu Leu Gly Ser Pro Lys Leu65 70 75
80Arg Thr Leu Ala Arg Gly Leu Ser Pro Ala Tyr Leu Arg Phe Gly Gly
85 90 95Thr Lys Thr Asp Phe Leu Ile Phe Asp Pro Lys Lys Glu Ser Thr
Phe 100 105 110Glu Glu Arg Ser Tyr Trp Gln Ser Gln Val Asn Gln Asp
Ile Cys Lys 115 120 125Tyr Gly Ser Ile Pro Pro Asp Val Glu Glu Lys
Leu Arg Leu Glu Trp 130 135 140Pro Tyr Gln Glu Gln Leu Leu Leu Arg
Glu His Tyr Gln Lys Lys Phe145 150 155 160Lys Asn Ser Thr Tyr Ser
Arg Ser Ser Val Asp Val Leu Tyr Thr Phe 165 170 175Ala Asn Cys Ser
Gly Leu Asp Leu Ile Phe Gly Leu Asn Ala Leu Leu 180 185 190Arg Thr
Ala Asp Leu Gln Trp Asn Ser Ser Asn Ala Gln Leu Leu Leu 195 200
205Asp Tyr Cys Ser Ser Lys Gly Tyr Asn Ile Ser Trp Glu Leu Gly Asn
210 215 220Glu Pro Asn Ser Phe Leu Lys Lys Ala Asp Ile Phe Ile Asn
Gly Ser225 230 235 240Gln Leu Gly Glu Asp Phe Ile Gln Leu His Lys
Leu Leu Arg Lys Ser 245 250 255Thr Phe Lys Asn Ala Lys Leu Tyr Gly
Pro Asp Val Gly Gln Pro Arg 260 265 270Arg Lys Thr Ala Lys Met Leu
Lys Ser Phe Leu Lys Ala Gly Gly Glu 275 280 285Val Ile Asp Ser Val
Thr Trp His His Tyr Tyr Leu Asn Gly Arg Thr 290 295 300Ala Thr Lys
Glu Asp Phe Leu Asn Pro Asp Val Leu Asp Ile Phe Ile305 310 315
320Ser Ser Val Gln Lys Val Phe Gln Val Val Glu Ser Thr Arg Pro Gly
325 330 335Lys Lys Val Trp Leu Gly Glu Thr Ser Ser Ala Tyr Gly Gly
Gly Ala 340 345 350Pro Leu Leu Ser Asp Thr Phe Ala Ala Gly Phe Met
Trp Leu Asp Lys 355 360 365Leu Gly Leu Ser Ala Arg Met Gly Ile Glu
Val Val Met Arg Gln Val 370 375 380Phe Phe Gly Ala Gly Asn Tyr His
Leu Val Asp Glu Asn Phe Asp Pro385 390 395 400Leu Pro Asp Tyr Trp
Leu Ser Leu Leu Phe Lys Lys Leu Val Gly Thr 405 410 415Lys Val Leu
Met Ala Ser Val Gln Gly Ser Lys Arg Arg Lys Leu Arg 420 425 430Val
Tyr Leu His Cys Thr Asn Thr Asp Asn Pro Arg Tyr Lys Glu Gly 435 440
445Asp Leu Thr Leu Tyr Ala Ile Asn Leu His Asn Val Thr Lys Tyr Leu
450 455 460Arg Leu Pro Tyr Pro Phe Ser Asn Lys Gln Val Asp Lys Tyr
Leu Leu465 470 475 480Arg Pro Leu Gly Pro His Gly Leu Leu Ser Lys
Ser Val Gln Leu Asn 485 490 495Gly Leu Thr Leu Lys Met Val Asp Asp
Gln Thr Leu Pro Pro Leu Met 500 505 510Glu Lys Pro Leu Arg Pro Gly
Ser Ser Leu Gly Leu Pro Ala Phe Ser 515 520 525Tyr Ser Phe Phe Val
Ile Arg Asn Ala Lys Val Ala Ala Cys Ile 530 535
5401421RNAArtificial SequenceA synthetic siRNA 14ggacuggacu
ugaucuuugu u 211521RNAArtificial SequenceA synthetic siRNA
15gaacagcacc uacucaagau u 211636DNAArtificial SequenceA synthetic
primer 16ggtggtggat ccacgcagct cctgacggct attccc
361736DNAArtificial SequenceA synthetic primer 17ggtggtggat
cccaggctca gcgccagcgc gcacag 361829DNAArtificial SequenceA
synthetic primer 18ctagctagct tgcaaagcac ctgcacctg
291927DNAArtificial SequenceA synthetic primer 19ctagctagcg
aggtgctggg aggggtc 272029DNAArtificial SequenceA synthetic primer
20ctatagggag acccaagctt ggtaccgag 292125DNAArtificial SequenceA
synthetic primer 21ccggaattca gcacctgcac ctgag 252211PRTHomo
sapiens 22Ser Ile Val Glu Lys Ser Ile Leu Leu Thr Glu1 5 10
* * * * *
References