U.S. patent application number 12/948012 was filed with the patent office on 2011-06-09 for method for differentiating between multiple sclerosis subtypes.
This patent application is currently assigned to Dianovix, Inc.. Invention is credited to Virender BHAN, John Gillard, Andrea Hebb, Martin Holcik, Robert G. Korneluk, George Robertson.
Application Number | 20110136133 12/948012 |
Document ID | / |
Family ID | 38337952 |
Filed Date | 2011-06-09 |
United States Patent
Application |
20110136133 |
Kind Code |
A1 |
BHAN; Virender ; et
al. |
June 9, 2011 |
METHOD FOR DIFFERENTIATING BETWEEN MULTIPLE SCLEROSIS SUBTYPES
Abstract
Disclosed herein is a method for differentiating between
multiple sclerosis subtypes in a patient. The method comprises a)
determining an amount of an IAP gene expression level in a blood
sample obtained from the patient; and b) correlating the amount of
the IAP gene expression level in the blood sample with the presence
of a multiple sclerosis subtype in the patient.
Inventors: |
BHAN; Virender; (Halifax,
CA) ; Gillard; John; (Baie D'Urfe, CA) ; Hebb;
Andrea; (Nova Scotia, CA) ; Holcik; Martin;
(Ottawa, CA) ; Korneluk; Robert G.; (Ottawa,
CA) ; Robertson; George; (Halifax, CA) |
Assignee: |
Dianovix, Inc.
Halifax
CA
|
Family ID: |
38337952 |
Appl. No.: |
12/948012 |
Filed: |
November 17, 2010 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11702657 |
Feb 6, 2007 |
7858309 |
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12948012 |
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60765734 |
Feb 7, 2006 |
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Current U.S.
Class: |
435/7.1 |
Current CPC
Class: |
C12Q 2600/158 20130101;
G01N 2800/285 20130101; C12Q 1/6883 20130101; C12Q 2600/112
20130101; G01N 33/564 20130101 |
Class at
Publication: |
435/7.1 |
International
Class: |
G01N 33/53 20060101
G01N033/53 |
Claims
1. A method for identifying a patient suffering from active
relapsing remitting multiple sclerosis, the method comprising: a)
determining an amount of XIAP and HIAP-2 gene expression levels in
peripheral blood mononuclear (PBMN) cells obtained from the
patient; and b) comparing the amount of the XIAP and HIAP-2 gene
expression levels in the PBMN cells with the XIAP and HIAP-2 gene
expression levels of control subjects, the gene expression levels
being determined by measuring the levels of XIAP protein and HIAP-2
protein in the PBMN cells, an increase in the XIAP and HIAP-2 gene
expression levels being an indication that the patient is suffering
from active relapsing remitting multiple sclerosis.
2. The method, according to claim 1, in which the control subjects
are those having benign MS or are healthy normal subjects.
3. The method, according to claim 1, in which the PBMN cells are
isolated from a blood sample taken from the patient.
4. The method, according to claim 1, in which the levels of XIAP
protein and HIAP-2 protein are measured using an immunoassay.
5. A method for determining whether a patient suffering from active
relapsing remitting multiple sclerosis is at risk of developing
secondary progressive multiple sclerosis, the method comprising: a)
determining an amount of XIAP and HIAP-2 gene expression levels in
peripheral blood mononuclear (PBMN) cells obtained from the
patient; and b) comparing the amount of the XIAP and HIAP-2 gene
expression levels in the PBMN cells with the XIAP and HIAP-2 gene
expression levels of control subjects, the gene expression levels
being determined by measuring the levels of XIAP protein and HIAP-2
protein in the PBMN cells, an increase in the XIAP and HIAP-2 gene
expression levels being an indication that the patient is at risk
of developing secondary progressive multiple sclerosis.
6. The method, according to claim 5, in which the control subjects
are those having benign MS or are healthy normal subjects.
7. The method, according to claim 5, in which the levels of XIAP
protein and HIAP-2 protein are measured using an immunoassay.
8. The method, according to claim 5, in which the PBMN cells are
isolated from a blood sample taken from the patient.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] Applicants hereby claim priority from previously filed U.S.
Provisional Patent Application Ser. No. 60/765,734, filed Feb. 7,
2006, the entire contents of which are hereby incorporated by
reference.
FIELD OF THE INVENTION
[0002] The present invention concerns methods for differentiating
between multiple sclerosis subtypes, and more particularly to
methods of using different IAP expression levels as markers for the
multiple sclerosis subtypes.
BACKGROUND OF THE INVENTION
[0003] Multiple sclerosis (MS) is a progressive neurological
disorder characterized by an autoimmune mediated attack against the
myelin sheath in the CNS resulting in inflammation, demyelination,
gliosis and ultimately axonal degeneration [Bruck and Stadelmann
2003]. The clinical course of MS has been divided into four major
categories: RR, SP, PP and benign. Patients who have clinical
relapses every few months or years with intervening periods of
clinical stability define RRMS. RRMS is twice as common in females
than males in the second or third decade of life [Noseworthy et al.
2000]. Although the majority of MS patients are initially diagnosed
with RRMS, over time increasing numbers of these individuals
convert to SPMS characterized by a gradual decline in neurological
function [Trojano et al. 2003]. Approximately 15% of MS patients
have PPMS characterized by an absence of clinical relapses and an
unrelenting deterioration of neurological function from disease
onset [McDonnell and Hawkins 2002]. PPMS is characterized by
relatively late-onset (mean age .about.39 years) although it has
been suggested based on clinical and MRI data that the pre-clinical
phase of PPMS occurs during the same time frame as in RRMS. In PPMS
as in RRMS the CNS lesions have the same age of onset, but it takes
10 years for PPMS patients to develop symptoms [McDonnell et al.
2003]. MRI with the contrast agent gadolinium is often employed
during or following an initial attack to identify lesions within
the CNS that are consistent with a diagnosis of MS. MRI is also
used at protracted intervals in MS patients to identify new areas
of demyelinated plaques within the brain and spinal cord [Calabresi
2004]. Moreover, MRI activity correlates with immune cell
perturbations in early possible MS. For example, Rinaldi et al.
(2006) demonstrated that distinct changes in peripheral lymphocyte
subsets occur over the course of 1 year, which differentiate MRI
active, and MRI inactive patients following a clinically isolated
syndrome. Yet results obtained by MRI do not correlate with
clinical disability and are therefore not recommended as
therapeutic end-points for new MS therapeutics [Siva 2006]. In
addition to RRMS, SPMS and PPMS, there is a benign form of the
disease that affects approximately 15% of RRMS patients. Benign MS
is arbitrarily defined in RRMS patients who after more than 10 to
15 years following initial diagnosis are still mobile and show only
mild deficits (EDSS.ltoreq.4). Typically, these patients show
little or no progression after their initial attack. Moreover,
those patients with an EDSS score of .ltoreq.2 and disease duration
of more than 10 to 15 years tend to maintain a low EDSS disability
score for an additional 10 years. Benign MS requires no therapeutic
intervention, however, it is not possible to diagnose this form of
MS until at least 5 to 10 years from MS onset [Hawkins and
McDonnell 1999; Pittock et al. 2004]. Unfortunately, there are no
diagnostic tests that would allow a clinician to predict whether a
newly diagnosed MS patient will follow a benign or aggressive
disease course.
[0004] MS is considered to be a T cell-mediated autoimmune disease
of the brain and spinal cord [Traugott et al. 1983; Vizier et al.
1999]. While there appears to be a localized CNS immune response,
peripheral immune cell abnormalities appear to correlate with
central disease activity [Hafler and Weiner 1989] and may precede
MRI activity. Apoptosis is an important mechanism in immune system
regulation, responsible for elimination of autoreactive
T-lymphocytes (T cells), B-lymphocytes (B cells) and monocytes from
the circulation and prevention of their entry into the CNS [Mahoney
and Rosen 2005; Todaro et al. 2004]. It has been hypothesized that
a genetic predisposition exists in MS patients whereby a failure of
autoreactive T cells and B cells as well as activated macrophages
to undergo apoptosis contributes to the pathogenesis of MS [Bernard
and Derosbo 1992; Pender 1998; Pender and Rist 2001]. Consistent
with this hypothesis expression of members of the IAP family of
anti-apoptotic proteins are elevated in mitogen (PHA) stimulated T
cells derived from the CSF or blood of MS patients relative to
healthy or neurological control subjects [Segal and Cross 2000;
Seki et al. 1988; Semra et al. 2002; Sharief et al. 2002b; Sharief
and Semra 2001; Tsukamoto et al. 1986]. The IAP family of
anti-apoptotic genes encodes proteins that directly bind to and
inactivate initiator and effector caspases, a group of cysteinyl
proteases that mediate the initiation and execution of apoptosis
[Holcik et al. 2001; Salvesen and Duckett 2002]. First discovered
in baculovirus, the IAPs are well conserved in eukaryotes, ranging
from yeast to humans and to date, eight human IAPs have been
identified [Holcik et al. 2001; Nachmias et al. 2004]. Importantly,
IAPs are the only intrinsic inhibitors of caspases. The IAPs are
typified by the presence of a variable number of highly conserved
domains about 70 amino acids in length, known as BIR domains, which
are critical for anti-apoptotic activity. For example, while XIAP,
HIAP-1 and HIAP-2 contain three BIR domains, survivin possesses
only one BIR domain. Although highly similar, the individual BIR
domains are not functionally equivalent. The BIR2 domain and the
preceding linker region of XIAP, HIAP-1, and HIAP-2 facilitate the
interaction with and suppression of caspases 3 and 7; the two most
potent effector caspases [Eckelman and Salvesen 2006; Nachmias et
al. 2004; Robertson et al. 2000]. Inhibition of the initiator
caspase 9 is accomplished by the BIR3 domain. While XIAP, HIAP-1
and HIAP-2 possess BIR domains 2 and 3 capable of binding caspases
7 and 9, only XIAP contains critical domain residues capable of
direct caspase inhibition [Eckelman and Salvesen 2006]. In addition
to BIR domains, XIAP, HIAP-1 and HIAP-2 possess a carboxy-terminal
RING zinc finger motif that has E3 ubiquitin ligase activity
targeting caspases for degradation by proteosomes [Holcik et al.
2001]. In addition, it has been shown recently that IAPs are
themselves controlled by ubiquitin-mediated degradation. For
example, HIAP-1 is a direct target for HIAP-2-mediated
ubiquitination and proteosomal degradation [Conze et al. 2005]. The
RING domain of XIAP also mediates polyubiquitination of TAK-1, an
enzyme responsible for activation of the pro-apoptotic kinase, JNK
[Kaur et al. 2005]. In this fashion, XIAP is able to target TAK-1
for degradation by the proteosome thereby preventing JNK-mediated
apoptosis. Structurally similar, both HIAP-1 and HIAP-2 possess a
CARD, a highly conserved domain noted to promote homodimerization
and oligomerization with other CARD containing proteins. While
elevated expression of XIAP, HIAP-1, HIAP-2 and survivin in
mitogen-stimulated T cells from patients with active RRMS
correlates with clinical features of disease activity, deficits in
Fas mediated cell death [Comi et al. 2000] and T cell resistance to
apoptosis [Sharief et al. 2002b; Sharief and Semra 2001], a
systematic examination of the expression patterns of these genes in
whole blood, PBMN and resting T cells in patients with various
forms of MS has yet to be done. Given that the failed apoptosis of
auto-reactive T cells has been implicated in MS pathogenesis and
that MS is a clinically heterogeneous disorder [Chofflon 2005], it
would be advantageous if specific patterns of IAP expression in
different immune cell subtypes could be measured and correlated
with distinct forms of the disease. Furthermore, it would be highly
advantageous to develop a reliable, rapid and inexpensive
diagnostic test for multiple sclerosis subtypes based on specific
patterns of basal IAP gene expression in peripheral immune cells.
Finally, a diagnostic test would allow clinicians to decide whether
interferon drug treatment is appropriate for a specific disease
subtype.
SUMMARY OF THE INVENTION
[0005] We have unexpectedly discovered that human patients
suffering from the major categories (or subtypes) of multiple
sclerosis (MS) have basal IAP gene expression profiles that
correlate with the disease severity. Specifically, we have
discovered that XIAP and HIAP-2 are differentially expressed in
high levels and are associated with aggressive forms of the disease
including active relapsing remitting MS and secondary progressive
MS. Advantageously, the gene expression profiles of XIAP and HIAP-2
are useful as diagnostic markers that may aid early diagnosis of
the aggressive forms of MS. Furthermore, the unique IAP gene
expression profiles allow differentiation between the various
subtypes of MS. With early diagnosis, patients can be treated more
rapidly than previously allowable thereby ensuring optimal
therapeutic response. Moreover, the differences in IAP expression
profiles are predictive of interferon-.beta. (IFN-.beta.)
responsiveness, which will allow clinicians to appropriately select
patients for whom the use IFN-.beta. drugs will provide maximum
benefit and avoid the use of IFN-.beta. drugs, which are expensive,
on patients who suffer from benign and primary progressive MS for
which little or no therapeutic benefit will be afforded. Moreover,
in patients suffering from PPMS, we have also discovered that
survivin expression is elevated in the resting T cells compared to
XIAP, HIAP 1 and HIAP-2. Surprisingly, in mRNA extracted from whole
blood, NAIP mRNA levels were elevated in all forms of MS except
those patients with benign MS or normal subjects.
[0006] According to one embodiment of the present invention, there
is provided a method for differentiating between multiple sclerosis
subtypes in a patient, the method comprising: [0007] a) determining
an amount of an IAP gene expression level in a blood sample
obtained from the patient; and [0008] b) correlating the amount of
the IAP gene expression level in the blood sample with the presence
of a multiple sclerosis subtype in the patient.
[0009] In one aspect, typically the IAP gene expression level is
compared those of control subjects. An increase in the IAP gene
expression level relative to those of the control subjects
indicates that the patient is suffering from the MS subtype. The
control subjects are those having benign MS or are healthy normal
subjects. The MS subtype is benign MS, quiescent relapsing
remitting MS, active relapsing remitting MS, primary progressive MS
or secondary progressive MS. The IAP gene expression level is
determined by measuring the levels of transcribed IAP mRNA in the
blood sample. The level of IAP mRNA is measured using quantitative
real time polymerase chain reaction (qRT-PCR).
[0010] In one aspect of the present invention, the IAP gene
expression level is determined by measuring the level of IAP
protein in the blood sample. The IAP protein level is measured
using an immunoassay.
[0011] In another aspect, the IAP gene encodes an IAP protein
selected from NAIP, XIAP, HIAP-1, HIAP-2 or survivin.
[0012] In another aspect, typically peripheral blood mononuclear
(PBMN) cells are isolated from the blood sample. The IAP gene
expression level is measured in the PBMNs. The IAP gene expression
level is compared to those of control subjects, an increase in the
IAP gene expression level relative to those of the control subjects
indicates that the patient is suffering from the MS subtype. The
increased gene expression level includes increased levels of XIAP
mRNA and HIAP-2 mRNA. The MS subtype is active relapsing remitting
MS. The MS subtype is secondary progressive MS. Typically, the
control subjects are those having benign MS, or are healthy normal
subjects.
[0013] In another aspect, typically T cells are isolated from the
blood sample. The IAP gene expression level is measured in the T
cells. The T cells are resting T cells.
[0014] In one aspect, typically, the IAP gene expression level is
compared to those of control subjects, an increase in the IAP gene
expression level relative to those of the control subjects
indicates that the patient is suffering from the MS subtype. The
increased gene expression level includes increased levels of HIAP-1
mRNA or HIAP-2 mRNA. The increased levels of only HIAP-1 mRNA
indicate that the patient is suffering from quiescent relapsing
remitting MS. The increased levels of HIAP-1 mRNA and HIAP-2 mRNA
levels indicate that the patient is suffering from active relapsing
remitting MS. The increased levels of only HIAP-2 mRNA indicate
that the patient is suffering from secondary progressive MS. The
increased gene expression level includes increased levels of
survivin mRNA. The increased level of survivin mRNA indicates that
the patient is suffering from primary progressive MS. The control
subjects are those having benign MS, or are healthy normal
subjects. The level of HIAP-2 expression correlates to the degree
of disability measured by EDSS scores.
[0015] In another aspect, the blood sample is whole blood. The IAP
gene expression is measured in the whole blood. The IAP gene
expression level is compared to those of control subjects, an
increase in the IAP gene expression level relative to those of the
control subjects indicates that the patient is suffering from the
MS subtype. The increased gene expression level includes increased
levels of NAIP mRNA in patients who are suffering from relapsing
remitting MS, quiescent relapsing remitting MS, primary progressive
MS and secondary progressive MS. The control subjects are those
having benign MS or are healthy normal subjects.
[0016] According to another embodiment of the present invention,
there is provided a method for differentiating active relapsing
remitting multiple sclerosis in a patient, the method comprising:
[0017] a) determining an amount of XIAP and HIAP-2 gene expression
levels in peripheral blood mononuclear (PBMN) cells obtained from
the patient; and [0018] b) comparing the amount of the XIAP and
HIAP-2 gene expression levels in the PBMNs with the XIAP and HIAP-2
gene expression levels of control subjects, an increase in the XIAP
and HIAP-2 gene expression levels being an indication that the
patient is suffering from active relapsing remitting multiple
sclerosis.
[0019] According to another embodiment of the present invention,
there is provided a method for differentiating secondary
progressive multiple sclerosis in a patient, the method comprising:
[0020] a) determining an amount of XIAP and HIAP-2 gene expression
levels in peripheral blood mononuclear (PBMN) cells obtained from
the patient; and [0021] b) comparing the amount of the XIAP and
HIAP-2 gene expression levels in the PBMNs with the XIAP and HIAP-2
gene expression levels of control subjects, an increase in the XIAP
and HIAP-2 gene expression levels being an indication that the
patient is suffering from secondary progressive multiple
sclerosis.
[0022] According to another embodiment of the present invention,
there is provided a method for differentiating quiescent relapsing
remitting multiple sclerosis in a patient, the method comprising:
[0023] a) determining an amount of HIAP-1 gene expression level in
T cells obtained from the patient; and [0024] b) comparing the
amount of the HIAP-1 gene expression level in the T cells with the
HIAP-1 gene expression levels of control subjects, an increase in
the HIAP-1 gene expression levels being an indication that the
patient is suffering from quiescent relapsing remitting multiple
sclerosis.
[0025] According to another embodiment of the present invention,
there is provided a method for differentiating active relapsing
remitting multiple sclerosis in a patient, the method comprising:
[0026] a) determining an amount of HIAP-1 and HIAP-2 gene
expression levels in T cells obtained from the patient; and [0027]
b) comparing the amount of the HIAP-1 and HIAP-2 gene expression
levels in the T cells with the HIAP-1 and HIAP-2 gene expression
levels of control subjects, an increase in the HIAP-1 and HIAP-2
gene expression levels being an indication that the patient is
suffering from active relapsing remitting multiple sclerosis.
[0028] According to an alternative embodiment of the present
invention, there is provided a method for differentiating between
quiescent and active relapsing remitting multiple sclerosis in a
patient, the method comprising: [0029] a) determining an amount of
HIAP-1 and HIAP-2 gene expression levels in T cells obtained from
the patient; and [0030] b) comparing the amount of the HIAP-1 and
HIAP-2 gene expression levels in the T cells with the HIAP-1 and
HIAP-2 gene expression levels of control subjects, either an
increase in only HIAP-1 gene expression levels being an indication
that the patient is suffering from quiescent relapsing remitting
multiple sclerosis, or an increase in both the HIAP-1 and HIAP-2
gene expression levels being an indication that the patient is
suffering from active relapsing remitting multiple sclerosis.
[0031] According to another alternative embodiment of the present
invention, there is provided a method for differentiating secondary
progressive multiple sclerosis in a patient, the method comprising:
[0032] a) determining an amount of HIAP-2 gene expression level in
T cells obtained from the patient; and [0033] b) comparing the
amount of the HIAP-2 gene expression level in the T cells with the
HIAP-2 gene expression levels of control subjects, an increase in
the HIAP-2 gene expression levels being an indication that the
patient is suffering from secondary progressive multiple
sclerosis.
[0034] According to another embodiment of the present invention,
there is provided a method for differentiating primary progressive
multiple sclerosis in a patient, the method comprising: [0035] a)
determining an amount of survivin gene expression level in T cells
obtained from the patient; and [0036] b) comparing the amount of
the survivin gene expression level in the T cells with the survivin
gene expression levels of control subjects, an increase in the
survivin gene expression levels being an indication that the
patient is suffering from primary progressive multiple
sclerosis.
[0037] According to another embodiment of the present invention,
there is provided a method for differentiating between benign and
either relapsing remitting MS, primary progressive MS or secondary
progressive MS in a patient, the method comprising: [0038] a)
determining an amount of NAIP gene expression levels in whole blood
obtained from the patient; and [0039] b) comparing the amount of
NAIP gene expression levels with the amount of NAIP gene expression
levels in control subjects, an increase in the NAIP gene expression
levels being an indication that the patient is suffering from
either relapsing remitting MS, primary progressive MS or secondary
progressive MS and not benign MS.
[0040] According to another embodiment of the present invention,
there is provided a method of testing a patient's suitability for
interferon-.beta. treatment of multiple sclerosis, the method
comprising: [0041] a) determining an amount of an IAP gene
expression level in a blood sample obtained from the patient
suspected of having an aggressive subtype of multiple sclerosis;
and [0042] b) comparing the amount of the IAP gene expression level
to the IAP gene expression levels of control subjects, an increase
in IAP gene expression levels being an indication that the patient
is suffering from an aggressive subtype of multiple sclerosis, the
patient being suitable for treatment with interferon-.beta..
[0043] According to another embodiment of the present invention,
there is provided a method of identifying whether a patient is at
risk of developing secondary progressive multiple sclerosis from
active relapsing remitting multiple sclerosis, the method
comprising: [0044] a) obtaining a blood sample for the patient; and
[0045] b) comparing XIAP mRNA levels in PBMNs isolated from the
sample, and HIAP-1 and HIAP-2 mRNA levels in T cells isolated from
the sample, with those of a control subject, an increase in the
XIAP mRNA levels in the PBMNs and an increase the HIAP-2 mRNA
levels in the T cells, and normal HIAP-1 levels in the T cells,
being an indication that the patient is at risk of developing
secondary progressive MS. The method further including detecting a
normalization of HIAP-1 in T cells.
[0046] According to an alternative embodiment of the present
invention, there is provided use of IAP mRNA expression or IAP
protein expression as a biomarker for the differentiation of
multiple sclerosis subtypes in a subject, an increased level of
expression compared to control subjects being an indication that
the patient has a multiple sclerosis subtype.
[0047] According to another embodiment of the present invention,
there is provided a method for monitoring the progress of a
multiple sclerosis therapy of a patient, the method comprising:
[0048] a) determining an amount of an IAP gene expression level in
a first blood sample obtained from the patient at first time
period; [0049] b) determining an amount of the IAP gene expression
level in a second blood sample obtained from the patient at a
second time period; and [0050] b) comparing in the IAP gene
expression levels, a decrease in the IAP gene expression level at
the second time period being an indication that the patient is
responding to the multiple sclerosis therapy.
[0051] According to an alternative embodiment of the present
invention, there is provided a diagnostic kit for differentiating a
patient suspected of having a subtype of multiple sclerosis, the
kit comprising: [0052] a) a vessel or vessels for receiving a blood
sample from the subject; [0053] b) an agent that specifically
detects IAP protein or amplifies IAP mRNA; and [0054] c) printed
instructions for detecting the IAP protein or the amplified IAP
mRNA in the sample.
[0055] In one aspect, typically, the agent for amplifying the IAP
mRNA are the primers and probes selected form Table 2. The IAP
protein is detected using immunoassays. The immunoassay is an
ELISA.
[0056] According to another embodiment of the present invention,
there is provided a method of differentiating between multiple
sclerosis subtypes in a patient blood sample, the method
comprising: [0057] a) determining an amount of an IAP gene
expression level in the blood sample; and [0058] b) correlating the
amount of the IAP gene expression level in the blood sample with
the presence of a multiple sclerosis subtype.
[0059] According to an alternative embodiment of the present
invention, there is provided a method for the differentiation of a
multiple sclerosis subtype in a subject, the method comprising:
[0060] a) obtaining a peripheral blood sample from the subject; and
[0061] b) detecting an increased level of IAP mRNA in the sample
compared to the level in a healthy subject, wherein the increased
level of the IAP mRNA is diagnostic of the multiple sclerosis
subtype in the subject.
[0062] Examples of IAPs that are useful in practicing the methods
of the invention include, but are not limited to, human and mouse
survivin, NAIP, XIAP, HIAP-1 (cIAP2), and HIAP-2 (cIAP1), which are
disclosed U.S. Pat. Nos. 5,919,912; 6,156,535; 6,656,704;
6,020,127; 6,656,684; 6,429,011; 6,994,957; US2002/0137028.
BRIEF DESCRIPTION OF THE DRAWINGS
[0063] Further aspects and advantages of the present invention will
become better understood with reference to the description in
association with the following Figures, wherein:
[0064] FIGS. 1A to 1C are graphs illustrating the relative
quantification of XIAP mRNA expression in RNA extracted from (A)
whole blood, (B) PBMN cells and (C) T cells employing qRT-PCR. The
graphs depict the expression of XIAP mRNA relative to the
expression of the endogenous control gene .beta..sub.2
microglobulin (2.sup.-.DELTA..DELTA.CT) in normal subjects (NS) and
patients with benign, Relapsing-Remitting (RR),
Secondary-Progressive (SP) or Primary-Progressive (PP) MS patients.
Quiescent (Q)=MS symptoms in remission at time of blood draw and
the patient has not experienced any relapses in the 2 years prior
to blood draw; Active (A)=MS symptoms are active at time of blood
draw and the patient has experienced at least one relapse in the 2
years prior to blood draw. (A) XIAP gene expression in whole blood
was not affected in MS relative to NS. (B) XIAP gene expression is
increased in PBMN cell RNA of RRA and SPMS patients relative to NS.
Note also that XIAP mRNA levels are higher in patients whose
symptoms are active (RRA) rather than quiescent (RRQ). (C) XIAP
gene expression in T cells is similar among NS and all subtypes of
MS patients. *p<0.05.
[0065] FIGS. 2A to 2C are graphs illustrating the relative
quantification of HIAP-1 mRNA expression in RNA extracted from (A)
whole blood, (B) PBMN cells and (C) T cells employing qRT-PCR. The
graphs depict the expression of HIAP-1 mRNA relative to the
expression of the endogenous control gene .beta..sub.2
microglobulin (2.sup.-.DELTA..DELTA.CT) in normal subjects (NS) and
patients with benign, Relapsing-Remitting (RR),
Secondary-Progressive (SP) or Primary-Progressive (PP) MS patients.
Quiescent (Q)=MS symptoms in remission at time of blood draw and
the patient has not experienced any relapses in the 2 years prior
to blood draw; Active (A)=MS symptoms are active at time of blood
draw and the patient has experienced at least one relapse in the 2
years prior to blood draw. (A) HIAP-1 gene expression in whole
blood was not affected in MS relative to NS. (B) There appears to
be no change in HIAP-1 gene expression in PBMN cells of MS patients
relative to NS. (C) In contrast to XIAP gene expression levels in T
cells, HIAP-1 gene expression is increased in T cells of RRMS
patients irrespective of disease activity (RRQ and RRA) relative to
NS and patients with benign and PPMS. *p<0.05.
[0066] FIGS. 3A to 3C are graphs illustrating the relative
quantification of HIAP-2 mRNA expression in RNA extracted from (A)
whole blood, (B) PBMN cells and (C) T cells employing qRT-PCR. The
graphs depict the expression of HIAP-2 mRNA relative to the
expression of the endogenous control gene .beta..sub.2
microglobulin (2.sup.--.DELTA..DELTA.CT) in normal subjects (NS)
and patients with benign, Relapsing-Remitting (RR),
Secondary-Progressive (SP) or Primary-Progressive (PP) MS patients.
Quiescent (Q)=MS symptoms in remission at time of blood draw and
the patient has not experienced any relapses in the 2 years prior
to blood draw; Active (A)=MS symptoms are active at time of blood
draw and the patient has experienced at least one relapse in the 2
years prior to blood draw. (A) HIAP-2 gene expression in whole
blood was not affected in MS relative to NS. (B) HIAP-2 gene
expression is increased in PBMN cell RNA of RRA and SPMS patients
relative to NS. (C) The increased HIAP-2 expression in PBMN cells
is most likely due to increased HIAP-2 T cell gene expression.
HIAP-2 is increased in T cells of RRA and SPMS patients relative to
NS. *p<0.05.
[0067] FIGS. 4A to 4C are graphs illustrating the relative
quantification of survivin mRNA expression in RNA extracted from
(A) whole blood, (B) PBMN cells and (C) T cells employing qRT-PCR.
The graphs depict the expression of survivin mRNA relative to the
expression of the endogenous control gene .beta..sub.2
microglobulin (2.sup..DELTA..DELTA.CT) in normal subjects (NS) and
patients with benign, Relapsing-Remitting (RR),
Secondary-Progressive (SP) or Primary-Progressive (PP) MS patients.
Quiescent (Q)=MS symptoms in remission at time of blood draw and
the patient has not experienced any relapses in the 2 years prior
to blood draw; Active (A)=MS symptoms are active at time of blood
draw and the patient has experienced at least one relapse in the 2
years prior to blood draw. (A) Survivin gene expression in whole
blood was not affected in MS relative to NS. (B) Survivin gene
expression was not affected in PBMN cells of MS patients relative
to NS. (C) Survivin gene expression was increased in T cells of
patients with PPMS relative to NS and all other MS groups.
[0068] FIGS. 5A and 5B illustrate the IAP protein levels in
patients with different types of MS and normal control subjects. A.
XIAP protein levels in patients with different types of MS and
normal control subjects. In PBMN cells there was a difference in
XIAP protein levels between the various groups with increased
levels of protein detected in RRA and SP MS patients relative to
all other groups. These findings were matched by a concordant
increase in XIAP PBMN cell mRNA levels in patients with RRA and SP
MS relative to all other groups (see FIG. 1B). B. Optical density
analysis confirmed the increase of XIAP protein in patients with
RRA and SPMS (*p<0.05).
[0069] FIGS. 6A to 6C illustrate the HIAP-1 protein levels in
patients with different types of MS and normal control subjects.
(A) HIAP-1 protein levels in T cells from patients with RR, SP and
PP MS appeared to be increased relative to subjects with benign MS
and normal control subjects. (B) The variability of HIAP-1 protein
expression in PPMS patients was reminiscent of the changes observed
in mRNA (see FIG. 2C). (C) Optical density analysis confirmed the
increase of HIAP-1 in RRMS relative to normal subjects, benign
patients and patients with either SPMS or PPMS (*p<0.05).
[0070] FIGS. 7A to 7C illustrates the relative quantification of
NAIP mRNA expression in RNA extracted from (A) whole blood, (B)
PBMN cells and (C) T cells employing qRT-PCR. This graph depicts
the expression of NAIP mRNA relative to the expression of the
endogenous control gene .beta..sub.2 microglobulin
(2.sup.--.DELTA..DELTA.CT) in normal subjects (NS) and patients
with benign, Relapsing-Remitting (RR), Secondary-Progressive (SP)
or Primary-Progressive (PP) MS patients. Quiescent (Q)=MS symptoms
in remission at time of blood draw and the patient has not
experienced any relapses in the 2 years prior to blood draw; Active
(A)=MS symptoms are active at time of blood draw and the patient
has experienced at least one relapse in the 2 years prior to blood
draw. (A) NAIP gene expression in whole blood was increased in RRQ,
RRA and SPMS relative to normal subjects. (B) NAIP gene expression
was not affected in PBMN cells of MS patients relative to normal
control subjects. (C) NAIP gene expression appeared to be increased
in a subset of PPMS patients relative to normal control subjects
(P>0.05).
DETAILED DESCRIPTION OF THE INVENTION
Definitions
[0071] Unless otherwise stated, the following terms apply:
[0072] The singular forms "a", "an" and "the" include corresponding
plural references unless the context clearly dictates
otherwise.
[0073] As used herein, the term "comprising" is intended to mean
that the list of elements following the word "comprising" are
required or mandatory but that other elements are optional and may
or may not be present.
[0074] As used herein, the term "consisting of" is intended to mean
including and limited to whatever follows the phrase "consisting
of". Thus the phrase "consisting of" indicates that the listed
elements are required or mandatory and that no other elements may
be present.
[0075] As used herein the terms "apoptosis" is intended to mean the
process of cell death in which a dying cell displays a set of
well-characterized biochemical indicia that include cell membrane
blebbing, cell soma shrinkage, chromatin condensation, and DNA
laddering.
[0076] As used herein, the term "cell" is intended to mean a
single-cellular organism, a cell from a multi-cellular organism or
it may be a cell contained in a multi-cellular organism.
[0077] As used herein, the term "subject" or "patient" is intended
to mean humans and non-human mammals such as primates, cats, dogs,
swine, cattle, sheep, goats, horses, rabbits, rats, mice and the
like. In one example, the subject is a human.
[0078] As used herein, the term "IAP gene" is intended to mean a
gene encoding a polypeptide having at least one BIR domain and
which is capable of modulating (inhibiting or enhancing) apoptosis
in a cell or tissue. The IAP gene is a gene having about 50% or
greater nucleotide sequence identity to at least one of survivin,
NAIP, HIAP-1 (cIAP2), HIAP-2 (cIAP1), and XIAP. The region of
sequence over which identity is measured is a region encoding at
least one BIR domain and a ring zinc finger domain. Mammalian IAP
genes include nucleotide sequences isolated from any mammalian
source. In one example, the mammal is a human.
[0079] As used herein, the term "protein", "polypeptide" or
"polypeptide fragment" is intended to mean any chain of more than
two amino acids, regardless of post-translational modification, for
example, glycosylation or phosphorylation, constituting all or part
of a naturally occurring polypeptide or peptide, or constituting a
non-naturally occurring polypeptide or peptide.
[0080] As used herein, the term "IAP protein" or "IAP polypeptide"
is intended to mean a polypeptide or protein, or fragment thereof,
encoded by an IAP gene. Examples of IAP polypeptides include, but
are not limited, to survivin, NAIP, HAP-1 (cIAP2), HIAP-2 (cIAP1),
and XIAP.
[0081] As used herein, the term "blood sample" is intended to mean
whole blood taken from the periphery of the subject from which
immune cells, for example, peripheral blood mononuclear (PBMN)
cells; and T cells can be isolated.
[0082] As used herein, the term "IAP mRNA expression" is intended
to mean expression of IAP genes which encode survivin, NAIP, XIAP,
HIAP-1 and HIAP-2.
[0083] As used herein the term "IAP gene expression level" is
intended to mean a measurable amount of the IAP gene expressed in a
PBMN or a T cell, such as for example, an amount of IAP mRNA or an
amount of an IAP protein.
[0084] As used herein, the term "biomarker" is intended to mean a
detectable level of either an IAP mRNA or an IAP protein in such a
pattern characterizing a specific MS subtype.
[0085] As used herein, the term "multiple sclerosis subtype" is
intended to mean one or more of four categories of multiple
sclerosis and includes relapsing-remitting (RRMS),
secondary-progressive (SPMS), primary progressive (PPMS) and
benign. The term "relapsing-remitting multiple sclerosis" can be
further categorized into quiescent relapsing-remitting multiple
sclerosis (RRQ) and active relapsing-remitting multiple sclerosis
(RRA).
[0086] As used herein, the term "aggressive form of multiple
sclerosis" is intended to mean RRA and SPMS.
[0087] As used herein, the term "control subjects" is intended to
mean subjects who are healthy normal, or who have been diagnosed as
having benign MS.
[0088] We have unexpectedly discovered distinct patterns of IAP
mRNA and IAP protein level expression in whole blood, peripheral
blood mononuclear cells (PBMN) and resting T cells from healthy
subjects and patients with benign MS, quiescent RRMS (RRQ), active
RRMS (RRA), SPMS or PPMS. Taken together, these results demonstrate
that patterns of IAP expression in whole blood, PBMN and resting T
cells can be used to differentiate between, and are diagnostic of,
sub-types of MS. Thus, we can now design new (non-MRI based)
diagnostic tests for MS based on the detection of the IAP gene
expression levels and that these genes may serve as surrogate
biomarkers for therapeutics based on the treatment of MS by the
induction of apoptosis in auto-reactive immune cells.
[0089] Accordingly in an embodiment of the present invention, there
is provided a method for differentiating between multiple sclerosis
subtypes in a patient, the method comprising: a) determining an
amount of an IAP gene expression level in a blood sample obtained
from the patient; and b) correlating the amount of the IAP gene
expression level in the blood sample with the presence of a
multiple sclerosis subtype in the patient. For example, the IAP
gene expression level is compared to those of control subjects in
which an increase in the IAP gene expression level relative to
those of the control subjects indicates that the patient is
suffering from one of the MS subtypes. The MS subtypes include
benign MS, quiescent relapsing remitting MS, active relapsing
remitting MS, primary progressive MS or secondary progressive MS.
The control subjects are those subjects who have been previously
diagnosed as having benign MS or are healthy normal subjects.
[0090] The invention provides for quantitative detection and
determination of the IAP gene expression levels by measuring either
the levels of transcribed IAP mRNA or the level of IAP protein in
the blood sample. One skilled in the art will recognize that many
techniques are available to measure the levels of the aforesaid IAP
gene expression levels. The IAP genes encode an IAP protein
selected from NAIP, XIAP, HIAP-1, HIAP-2 or survivin. In one
example, IAP mRNA is measured using quantitative real time
polymerase chain reaction (qRT-PCR), which is described in more
detail below, whereas IAP protein level is measured using an
immunoassay.
[0091] Immunoassays for example include, but are not limited to,
competitive and non-competitive assay systems using techniques such
as western blots, radioimmunoassays, ELISA (enzyme linked
immunosorbent assay), "sandwich" immunoassays, immunoprecipitation
assays, precipitin reactions, gel diffusion precipitin reactions,
immunodiffusion assays, fluorescent immunoassays and the like. Such
assays are routine and well known in the art (see, e.g., Ausubel et
al, eds, 1994, Current Protocols in Molecular Biology, Vol. 1, John
Wiley & Sons, Inc., New York, which is incorporated by
reference herein in its entirety). Exemplary immunoassays are
described briefly below (but are not intended by way of
limitation).
[0092] Immunoprecipitation protocols generally comprise lysing a
population of cells in a lysis buffer such as RIPA buffer (1% NP-40
or Triton X-100, 1% sodium deoxycholate, 0.1% SDS, 0.15 M NaCl,
0.01 M sodium phosphate at pH 7.2, 1% Trasylol) supplemented with
protein phosphatase and/or protease inhibitors (e.g., EDTA, PMSF,
aprotinin, sodium vanadate), adding an antibody of interest to the
cell lysate, incubating for a period of time (e.g., 1-4 hours) at 4
degrees C., adding protein A and/or protein G sepharose beads to
the cell lysate, incubating for about an hour or more at 4 degrees
C., washing the beads in lysis buffer and re-suspending the beads
in SDS/sample buffer. The ability of the antibody to
immunoprecipitate a particular antigen can be assessed by, e.g.,
western blot analysis. One skilled in the art would be
knowledgeable as to the parameters that can be modified to increase
the binding of the antibody to an antigen and decrease the
background (e.g., pre-clearing the cell lysate with sepharose
beads). For further discussion regarding immunoprecipitation
protocols see, e.g., Ausubel et al, eds, 1994, Current Protocols in
Molecular Biology, Vol. 1, John Wiley & Sons, Inc., New York at
10.16.1.
[0093] Western blot analysis generally comprises preparing protein
samples, electrophoresis of the protein samples in a polyacrylamide
gel (e.g., 8%-20% SDS-PAGE depending on the molecular weight of the
antigen), transferring the protein sample from the polyacrylamide
gel to a membrane such as nitrocellulose, PVDF or nylon, blocking
the membrane in blocking solution (e.g., PBS with 3% BSA or non-fat
milk), washing the membrane in washing buffer (e.g., PBS-Tween 20),
blocking the membrane with primary antibody (the antibody of
interest) diluted in blocking buffer, washing the membrane in
washing buffer, blocking the membrane with a secondary antibody
(which recognizes the primary antibody, e.g., an anti-human
antibody) conjugated to an enzymatic substrate (e.g., horseradish
peroxidase or alkaline phosphatase) or radioactive molecule (e.g.,
.sup.32P or .sup.125I) diluted in blocking buffer, washing the
membrane in wash buffer, and detecting the presence of the antigen.
One skilled in the art would be knowledgeable as to the parameters
that can be modified to increase the signal detected and to reduce
the background noise. For further discussion regarding western blot
protocols see, e.g., Ausubel et al, eds, 1994, Current Protocols in
Molecular Biology, Vol. 1, John Wiley & Sons, Inc., New York at
10.8.1.
[0094] ELISAs comprise preparing antigen (i.e. an IAP polypeptide
biomarker), coating the well of a 96 well microtiter plate with the
antigen, adding the antibody of interest conjugated to a detectable
compound such as an enzymatic substrate (e.g., horseradish
peroxidase or alkaline phosphatase) to the well and incubating for
a period of time, and detecting the presence of the antigen. In
ELISAs the antibody of interest does not have to be conjugated to a
detectable compound; instead, a second antibody (which recognizes
the antibody of interest) conjugated to a detectable compound may
be added to the well. Further, instead of coating the well with the
antigen, the antibody may be coated to the well. In this case, a
second antibody conjugated to a detectable compound may be added
following the addition of the antigen of interest to the coated
well. One skilled in the art would be knowledgeable as to the
parameters that can be modified to increase the signal detected as
well as other variations of ELISAs known in the art. For further
discussion regarding ELISAs see, e.g., Ausubel et al, eds, 1994,
Current Protocols in Molecular Biology, Vol. 1, John Wiley &
Sons, Inc., New York at 11.2.1.
[0095] In one example, peripheral blood mononuclear (PBMN) cells
and T cells are typically isolated from the blood samples of the
patients and are analyzed for IAP gene expression levels as is
described in more detail below. The IAP gene expression levels are
compared to those of the control subjects, an increase in the IAP
gene expression level relative to those of the control subjects
indicates that the patient is suffering from one of the MS subtypes
described above.
[0096] Detection of certain IAP gene biomarkers are diagnostic of
the specific subtype of MS. For example, in MS patients with RRA
(but not RRQ) and SPMS, XIAP mRNA and protein levels were
selectively elevated in PBMN cells relative to normal control
subjects or patients with benign or PPMS. HIAP-2 mRNA was elevated
in PBMN cells of patients with RRA and SPMS relative to normal
control subjects and patients with a benign MS disease course. In T
cells, HIAP-2 mRNA levels were elevated in patients with RRMS
irrespective of disease activity and SPMS relative to normal
control subjects. The expression of HIAP-1 was selectively elevated
in resting T cells from RRMS patients irrespective of disease
activity relative to all other experimental groups. In PPMS
patients, survivin expression was elevated in T cells relative to
normal control subjects, RRMS and SPMS patients.
Distinguishing Between Specific MS Subtypes
[0097] As illustrated in Table 3 below, the diagnostic methods of
the invention can be used to differentiate between specific MS
subtypes. For example, in one alternative aspect of the invention,
there is provided a method for distinguishing between quiescent and
active forms of relapsing remitting multiple sclerosis in a
patient. The method comprises determining the amount of XIAP and
HIAP-2 gene expression levels in peripheral blood mononuclear
(PBMN) cells obtained from the patient. The amount of XIAP and
HIAP-2 gene expression levels are compared to XIAP and HIAP-2 gene
expression levels of control subjects, an increase in the gene
expression levels coupled with clinical presentation being an
indication that the patient is suffering from active relapsing
remitting multiple sclerosis. In addition, there is also provided a
method for distinguishing secondary progressive multiple sclerosis
in a patient. In this case, the method comprises determining an
amount of XIAP and HIAP-2 gene expression levels in peripheral
blood mononuclear (PBMN) cells obtained from the patient. The
amount of the XIAP and HIAP-2 gene expression levels are compared
to these gene expression levels of control subjects, an increase in
the XIAP and HIAP-2 gene expression levels being an indication that
the patient is suffering from secondary progressive multiple
sclerosis.
[0098] In another alternative aspect, there is provided a method
for differentiating quiescent relapsing remitting multiple
sclerosis in a patient. In this case, the method comprises
determining an amount of HIAP-1 gene expression level is determined
in T cells obtained from the patient. The amount of the HIAP-1 gene
expression level in the T cells is compared to the HIAP-1 gene
expression levels of control subjects, an increase in the HIAP-1
gene expression levels being an indication that the patient is
suffering from quiescent relapsing remitting multiple
sclerosis.
[0099] In addition, there is provided a method for differentiating
active relapsing remitting multiple sclerosis in a patient. In this
case, the method comprises determining an amount of HIAP-1 and
HIAP-2 gene expression levels in T cells obtained from the patient.
The amount of the HIAP-1 and HIAP-2 gene expression levels in the T
cells is compared to the HIAP-1 and HIAP-2 gene expression levels
of control subjects, an increase in the HIAP-1 and HIAP-2 gene
expression levels being an indication that the patient is suffering
from active relapsing remitting multiple sclerosis.
[0100] In certain circumstances, where a clinician suspects that a
patient has RRMS, but is uncertain as to whether the RRMS is
quiescent or active, there is provided a method for differentiating
between quiescent and active relapsing remitting multiple sclerosis
in a patient. This method comprises determining an amount of HIAP-1
and HIAP-2 gene expression levels in T cells obtained from the
patient. The amount of the HIAP-1 and HIAP-2 gene expression levels
in the T cells is compared to the HIAP-1 and HIAP-2 gene expression
levels of control subjects. An increase in only HIAP-1 gene
expression levels is an indication that the patient is suffering
from quiescent relapsing remitting multiple sclerosis, whereas an
increase in both the HIAP-1 and HIAP-2 gene expression levels is an
indication that the patient is suffering from active relapsing
remitting multiple sclerosis.
[0101] In another alternative aspect of the present invention,
there is provided a method for differentiating secondary
progressive multiple sclerosis in a patient. In this case, the
method comprises determining an amount of HIAP-2 gene expression
level in T cells obtained from the patient. The amount of the
HIAP-2 gene expression level in the T cells is compared to the
HIAP-2 gene expression levels of control subjects, an increase in
the HIAP-2 gene expression levels being an indication that the
patient is suffering from secondary progressive multiple
sclerosis.
[0102] In another alternative aspect of the present invention,
there is provided a method for differentiating primary progressive
multiple sclerosis in a patient. In this case, the method comprises
determining an amount of survivin gene expression level in T cells
obtained from the patient. The amount of the survivin gene
expression level in the T cells is compared to the survivin gene
expression levels of control subjects, an increase in the survivin
gene expression levels being an indication that the patient is
suffering from primary progressive multiple sclerosis.
[0103] Currently, benign MS cannot be distinguished from other
types of MS, including relapsing remitting MS relapsing remitting
MS, primary progressive MS or secondary progressive MS. In patients
who first present themselves to a clinician, no diagnostic tests
are available to distinguish the benign MS from quiescent relapsing
remitting MS. It would therefore be advantageous to distinguish
between benign MS and the other types of MS to prevent unneeded
treatment of the benign MS patients with interferon drugs. We have
shown that NAIP expression is the only biomarker in which there is
an increase in whole blood. RRQ, RRA and SPMS relative to normal
healthy subjects. There was no difference in benign or PPMS whole
blood NAIP. In T cells, a subset of PPMS patients showed an
increase in NAIP mRNA expression.
[0104] Thus, according to another aspect of the present invention,
there is provided a method for differentiating between benign and
either relapsing remitting MS, primary progressive MS or secondary
progressive MS in a patient. In this case, the method comprises
determining an amount of NAIP gene expression levels in whole blood
obtained from the patient. The NAIP gene expression levels are then
compared to the amount of NAIP gene expression levels in control
subjects, an increase in the NAIP gene expression levels being an
indication that the patient is suffering from either relapsing
remitting MS, primary progressive MS or secondary progressive MS
and not benign MS.
Determination of a Patient's Suitability for Interferon Drug
Treatment
[0105] One advantage of the methods of the present invention
concern a clinician's ability to appropriately treat MS sufferers
with interferon drugs, such as Rebif 22, Rebif 44, Avonex, and
Betaseron. In instances where such treatment is inappropriate, such
as in patients suffering from benign MS or PPMS, the clinician may
now first screen patients to eliminate those for which treatment
would be inappropriate. Thus, according to an alternative aspect of
the present invention, there is provided a method of testing a
patient's suitability for interferon-.beta. treatment of multiple
sclerosis. This method comprises determining an amount of an IAP
gene expression level in a blood sample obtained from the patient
suspected of having an aggressive subtype of multiple sclerosis.
The amount of the IAP gene expression level can then be compared to
the IAP gene expression levels of control subjects, an increase in
IAP gene expression levels being an indication that the patient is
suffering from an aggressive subtype of multiple sclerosis, the
patient being suitable for treatment with interferon-.beta..
[0106] For those patients for which interferon therapy is
appropriate, one aspect of the invention would be a method for
monitoring the progress of a multiple sclerosis therapy of a
patient. This method comprises determining an amount of an IAP gene
expression level in a first blood sample obtained from the patient
at first time period, followed by determining an amount of the IAP
gene expression level in a second blood sample obtained from the
patient at a second time period. The difference between the two
time periods who be determined by the type of therapy used by the
clinician and how quickly the patient is progressing. The IAP gene
expression levels would be compared and a decrease in the IAP gene
expression level at the second time period being an indication that
the patient is responding to the multiple sclerosis therapy. The
therapy could be continued until the IAP gene expression is
significantly diminished or essentially eliminated.
[0107] For those patients who present clinical symptoms of active
relapsing remitting MS, it is advantageous to determine whether the
patient is at risk of developing secondary progressive MS. Thus,
another alternative embodiment of the present invention provides a
method of identifying whether a patient is at risk of developing
secondary progressive multiple sclerosis from active relapsing
remitting multiple sclerosis, the method comprising: a) obtaining a
blood sample for the patient; and b) comparing XIAP mRNA levels in
PBMNs, and HIAP-1 and HIAP-2 mRNA levels in T cells, with those of
a control subject, elevated XIAP mRNA levels in the PBMNs, elevated
HIAP-2 mRNA levels in the T cells, and normal HIAP-1 levels in the
T cells, being an indication that the patient is at risk of
developing secondary progressive MS. Furthermore, the aforesaid
alternative method may further include detecting a normalization of
HIAP-1 in T cells. Such a change would suggest initiation of more
aggressive treatments such as Tysabri.RTM..
II: Diagnostic Kits
[0108] Generally, speaking a clinician's office may be adapted to
aid quick and reliable diagnosis of a patient suspected of having
one of the above mentioned subtypes of MS. Thus, according to one
embodiment of the invention, there is provided a diagnostic kit for
diagnosing a patient suspected of having a subtype of multiple
sclerosis. The kit comprises a vessel or vessels for receiving a
blood sample taken from the subject, an agent that specifically
detects IAP protein or amplifies IAP mRNA; and printed instructions
for detecting the IAP protein or the amplified IAP mRNA in the
sample.
[0109] For example, the kits can be used to detect any one or more
of the IAP gene expression levels, such as IAP mRNA or IAP
polypeptide described herein, which biomarkers are differentially
present in samples of a patient and normal subjects. The kits of
the invention have many applications. For example, the kits can be
used to differentiate if a subject has benign MS, quiescent or
active relapsing remitting MS, primary progressive MS or secondary
progressive MS. In another example, the kits can be used to
identify compounds that modulate expression of one or more of the
markers in in vitro or in vivo animal models to determine the
effects of treatment.
[0110] The IAP protein is detected using immunoassays as described
above.
[0111] In one example, a kit comprises (a) an antibody that
specifically binds to an IAP polypeptide; and (b) a detection
agent. Such kits can be prepared from the materials described in
U.S. Pat. No. 5,919,912.
[0112] In the case of IAP mRNA, the agent for amplifying the IAP
mRNA are the primers and probes selected from Table 2 below. In
some instances, the kit may further comprise instructions for
suitable operation parameters in the form of a label or a separate
insert.
[0113] The invention also includes a diagnostic kit which includes
a substantially isolated antibody specifically immunoreactive with
IAP polypeptide antigens, and means for detecting the binding of
the polypeptide antigen to the antibody. In example, the antibody
is attached to a solid support. In a specific example, the antibody
may be a monoclonal antibody. The detecting means of the kit may
include a second, labeled monoclonal antibody. Alternatively, or in
addition, the detecting means may include a labeled, competing
antigen.
[0114] Optionally, the kit may further comprise a standard or
control information so that a test sample can be compared with a
control information standard to determine if the test amount of a
marker detected in a sample is indicative of a MS subtype in a
patient clinically diagnosed with MS.
[0115] Optionally, the kit can further comprise instructions for
suitable operational parameters in the form of a label or a
separate insert. For example, the kit may have standard
instructions informing a consumer how to wash a probe after a
sample is contacted on the probe. In another example, the kit may
have instructions for pre-fractionating a sample to reduce
complexity of IAP proteins in the sample. In another example, the
kit may have instructions for automating the fractionation or other
processes.
[0116] The methods described above and below may also be carried
out on patient blood samples, which may have been obtained and
stored according to methods known to those skilled in the art of
blood sample handling and storage. Thus it is within the scope of
the present invention to provide a method of differentiating
between multiple sclerosis subtypes in a patient blood sample. In
this case, the method comprises determining an amount of an IAP
gene expression level in the blood sample, as described above, and
then correlating the amount of the IAP gene expression level in the
blood sample with the presence of a multiple sclerosis subtype.
Materials and Methods
[0117] The following examples are offered by way of illustration,
not by way of limitation. While specific examples have been
provided, the above description is illustrative and not
restrictive. Any one or more of the features of the previously
described embodiments can be combined in any manner with one or
more features of any other embodiments in the present invention.
Furthermore, many variations of the invention will become apparent
to those skilled in the art upon review of the specification. The
scope of the invention should, therefore, be determined not with
reference to the above description, but instead should be
determined with reference to the appended claims along with their
full scope of equivalents.
[0118] Unless otherwise stated, the following abbreviations are
used throughout:
CNS=central nervous system; CSF=cerebral spinal fluid;
EDSS=Expanded Disability Status Scale;
[0119] HIAP-1=human inhibitor of apoptosis protein-1; HIAP-2=human
inhibitor of apoptosis protein-2; IAP=inhibitor of apoptosis
protein;
MRI=Magnetic Resonance Imaging;
[0120] MS=multiple sclerosis; NAIP=meuronal apoptosis inhibitor
protein; PBMN cells=peripheral blood mononuclear cells;
RR=relapsing-remitting; RRQ=relapsing-remitting quiescent disease
activity; RRA=relapsing-remitting active disease; RRMS=relapsing
remitting Multiple Sclerosis, SP=secondary-progressive;
SPMS=secondary-progressive Multiple Sclerosis; PP=primary
progressive; PPMS=primary-progressive Multiple Sclerosis;
qRT-PCR=quantitative reverse transcriptase polymerase chain
reaction; and XIAP=X-linked inhibitor of apoptosis protein.
I. Patient Selection and Blood Sampling
[0121] Qualified clinical personnel obtained blood samples from MS
patients with Benign (n=12), RRMS (n=24), SPMS (n=22) and PPMS
(n=19) during the patients regularly scheduled visit to the
Dalhousie Multiple Sclerosis Research Unit (DMSRU). Research and
clinical personnel recruited 14 healthy volunteer subjects from the
community. All subjects gave informed consent prior to blood draw.
A practicing neurologist with a special interest in MS (VB) at the
DMSRU prior to study entry diagnosed all patients with definite MS
according to established diagnostic criteria [McDonald et al. 2001]
and determined each individual patient's level of disability and
disease progression employing the EDSS. Benign MS was characterized
in patients that had disease duration of more than 10 years and an
EDSS of 2.0 or less or in patients with disease duration of greater
than 15 years and an EDSS 3.0 or less. Relapsing-remitting MS
quiescent disease state (RRQ) was characterized in patients that
did not experience any relapses within the last 2 years and did not
experience EDSS progression over the same time period.
Relapsing-remitting MS active disease state (RRA) was characterized
in patients that had experienced 1 or more relapses in the last
year or gadolinium positive (Gd.sup.+) lesions on recent MRI.
Patients were diagnosed as having secondary-progressive MS (SPMS)
following a previous diagnosis of RRMS but were currently
experiencing progression of disability with or without concurrent
relapses. In comparison to RRMS most SPMS patients have an EDSS
greater than 4 and often greater than 6 as compared to the usual
EDSS course associated with RRMS. Primary progressive MS (PPMS) was
diagnosed in patients that displayed a progressive, non-phasic
neurological syndrome. Most patients presented as a spinal cord
syndrome or a cerebellar dysfunction coupled with Gd.sup.+ lesions
disseminated in space and time by MRI criteria with continued
clinical progression for at least one year, according to the
revised McDonald diagnostic criteria [Polman et al. 2005]. Patients
and normal control subjects were included if they were 18 years of
age or older, had no other major medical illness and gave written
informed consent. Subjects did not receive corticosteroid or immune
suppressive therapy within 3 months prior to blood draw. Subject
profiles are presented in Table 1
TABLE-US-00001 TABLE 1 MS Ave. Ave. Ave. Disease # Patients Ave.
Years on Subtype Gender Age .+-. S.D. EDSS .+-. S.D. Duration
(years) On DMT DMT .+-. S.D. NS 10 F; 9 M 39.7 .+-. 11.8 n/a n/a
n/a n/a Benign 14 F; 4 M 54.1 .+-. 6.4 1.8 .+-. 1.0 23.7 .+-. 6.1 0
6.3 .+-. 2.1 RRQ 15 F; 1 M 48.6 .+-. 7.9 2.5 .+-. 1.3 12.9 .+-. 6.9
12 3.0 .+-. 2.2 RRA 11 F; 4 M 42.1 .+-. 7.8 2.9 .+-. 1.5 9.3 .+-.
9.3 6 2.6 .+-. 2.8 SP 18 F; 6 M 55.3 .+-. 9.4 6.0 .+-. 1.3 22.6
.+-. 9.0 12 5.2 .+-. 2.3 PP 20 F; 11 M 57.7 .+-. 9.5 5.9 .+-. 1.9
17.8 .+-. 12.3 0 n/a NS = normal control subjects; Benign = Benign
MS; RRQ = RRMS quiescent disease activity RRA = RRMS active disease
activity; SP = SPMS; PP = PPMS; F = female; M = male; Ave. =
average; S.D. = standard deviation; DMT = disease modifying therapy
(Rebif 22, Rebif 44, Avonex, Betaseron, Copaxone).
[0122] Thirty-seven milliliters of blood was collected in four 8 ml
BD Vacutainer.RTM. sodium citrate Ficoll gradient tubes and two 2.5
ml Paxgene (Qiagen) whole blood RNA tubes. Our investigation sought
to determine not only if IAP levels were differentially affected in
specific subtypes of MS, but also whether these changes in IAP
expression could be detected in whole blood or peripheral blood
mononuclear (PBMN) cells in addition to resting T lymphocytes. The
blood samples were immediately transported at room temperature to
the Good Laboratory Practice (GLP) Accredited hematology laboratory
at the Queen Elizabeth Hospital, centrifuged at high speeds, and
the PBMN cells and T lymphocytes isolated from whole blood
employing negative selection and stored at -80.degree. C. until RNA
and protein extraction.
II. RNA Expression, Cell Purification, RNA Amplification and
Statistical Analyses
A. Whole Blood
[0123] Blood was collected in two 2.5 ml Paxgene RNA tubes, as last
blood-draw following collection in the 4 Ficoll-Gradient blood
tubes (below). Tubes were inverted several times to mix and left at
room temperature (RT) for 24 hours. Following the 24-hour RT
incubation period tubes were centrifuged at 3400.times.g in a
swinging bucket centrifuge for 10 minutes to pellet nucleic acids.
The pellets were washed, resuspended, and incubated in optimized
buffers containing Proteinase K to digest proteins followed by a
second centrifugation step to remove residual cell debris. The
supernatant was transferred to a fresh microcentrifuge tube,
ethanol added and the lysate applied to a Paxgene RNA spin column.
The column was washed and treated with RNAse-free DNAse (Qiagen)
and then pure RNA eluted according to the manufacturer's protocols
(Qiagen). Total RNA yields were measured by ultraviolet (UV)
absorbance and overall RNA quality was assessed by gel
electrophoresis and staining for visualization of RNA band
integrity. RNA samples were diluted in RNAse free water to give a
final concentration of 10 ng/.mu.l, prior to analysis of IAP gene
expression by qRT-PCR.
B. Isolation of RNA from Peripheral Blood Mononuclear Cells (PBMN)
and T Lymphocytes
[0124] Whole blood is made up of a heterogeneous population of
erythrocytes, granulocytes, and other peripheral blood mononuclear
(PBMN) cells that make it difficult to detect differential IAP gene
and protein expression that may occur in only a subset of immune
cell types. As such, in addition to blood collection in Paxgene
whole-blood RNA tubes, thirty-two ml of blood was collected in four
8 ml Ficoll-gradient tubes from each subject to isolate mononuclear
cells, including T and B lymphocytes as well as
monocytes/macrophages. Two of the tubes for each subject were used
to isolate PBMN cells and two of the tubes were used to isolate
resting (i.e. unactivated; not mitogen activated) T lymphocytes.
For the isolation of highly purified T lymphocytes
(2.times.10.sup.5) from whole blood of MS patients by negative
selection (StemCell Technologies, Vancouver, BC) four hundred
microliters (4) of RosetteSepT (Stem Cell Technologies) was added
to two of the four Ficoll-gradient tubes (Becton, Dickinson and
Company; BD Vacutainer.RTM. CPT.TM. Cell Preparation Tube with
Sodium Citrate) and incubated at room temperature for 20 minutes.
Negative selection was chosen over positive selection in order to
minimize T cell activation. For the isolation of PBMN cells,
RosetteSep T was withheld. All tubes were inverted twice to mix and
centrifuged at 1650-1800.times.g for 25 minutes in a swinging
bucket centrifuge. The T cells and PBMN cells were pipetted off
into separate 15 ml conical centrifugation tubes, treated with
ammonium chloride (StemCell Technologies, Vancouver, B.C.) for 10
minutes on ice to remove any remaining red blood cells, and
centrifuged at 1000.times.g for 10 minutes in a swinging bucket
centrifuge to pellet the cells. The red blood cells (RBC) and
polynuclear cells, including the neutrophils, the most abundant of
the white blood cells [Biswas et al. 2003; Stroncek et al. 1997]
were destroyed. Cell pellets were washed twice in phosphate
buffered saline/fetal bovine serum and stored at -80.degree. C.
until RNA and protein extraction. In most cases, pending
difficulties in blood withdrawal (i.e. vein collapsed) or tube
breakage, two T cell pellets and two PBMN cell pellets were
obtained for each subject. Total RNA was extracted from one T cell
pellet and one PBMN cell pellet from each patient using the Qiagen
RNeasy kit (Mississauga, Ontario) according to the manufacturer's
instructions. All sample preparations included RNAse-free DNAse
treatment. Total RNA yields were measured by UV absorbance. RNA
samples were diluted in RNAse free water to give a final
concentration of 10 ng/.mu.l.
III. Quantitative RT-PCR
[0125] Quantitative RT-PCR was performed to confirm changes in
NAIP, XIAP, HIAP-1, HIAP-2 and survivin gene expression in patients
with different subtypes of MS relative to normal control subjects.
Aegera Therapeutics Inc. provided Taqman probes and Taqman primers
for the IAPs. Total RNA (50 ng) isolated from whole blood, PBMN or
T cells was reverse transcribed to yield first-strand cDNA and
amplified using the Taqman one-step EZ RT-PCR Core reagents kit
(Applied Biosystems, Foster City, Calif., USA). For detection of
each IAP, forward and reverse primers were used at a concentration
of 600 nmol/L and all the Taqman fluorogenic probes at a
concentration of 200 nmol/L. The expression of beta .beta.2
microglobulin was used as an endogenous control reference (Applied
Biosystems, Foster City, Calif., USA). .beta.2 microglobulin was
amplified using Taqman .beta.2 Microglobulin Control Reagents Kit
(Applied Biosystems, Foster City, Calif., USA). The Taqman probe
and primer sequences for the IAPs are presented in Table 2. All
amplifications were done in triplicate within the same 96 well
plate and threshold cycle (CT) scores were averaged for subsequent
calculations of relative expression values. The CT scores represent
the cycle number at which the fluorescence signal (.DELTA.Rn)
crossed an arbitrary (user-defined) threshold. Data was extracted
and amplification plots generated with MJ Research Inc. (USA)
software. Quantification of IAP gene expression relative to .beta.2
microglobulin was calculated according to the experimental
protocol's 2.sup.-.DELTA..DELTA.CT method [Livak and Schmittgen
2001]. After the PCR amplification was finished the data were
analyzed using the software provided by MJ Research and then the
analyzed data was exported into an Excel/SPSS spreadsheet for
further statistical analysis. Results were expressed in Fold
increase or Relative to a "calibrator." The calibrator sample was
the RNA sample from a normal age-matched female subject. For
amplicons designed and optimized according to the Applied
Biosystems guidelines (amplicon size<150 bp), the efficiency is
close to one. Therefore, the amount of target, normalized to an
endogenous reference (i.e., .beta.2 microglobulin) and relative to
a calibrator (i.e., normal control RNA), is given by
2.sup.-.DELTA..DELTA.CT, where CT=Cycle Threshold (fractional cycle
number at which the amount of amplified target reaches a fixed
threshold), .DELTA.CT=CT, X-CT, R (difference in threshold cycles
for target and reference) and .DELTA..DELTA.CT=.DELTA.CT
(target)-.DELTA.CT (calibrator value). .DELTA..DELTA.CT scores for
the IAP mRNAs for each sample were subjected to separate one-way
analysis of variance (ANOVA) assessing the level of expression of
each of the genes among patients with different types of MS
(Benign, RR, SP, PP) and normal controls. The .DELTA..DELTA.CT
scores for the IAP mRNAs for RRMS patients were assessed according
to disease activity (RRQ or RRA) at the time of blood draw.
Graphpad Prism 4 (San Diego, Calif., USA) and SPSS 11.0 (SPSS,
Inc., Chicago, Ill., USA) software were used for all statistical
analyses. Individual group differences following significant ANOVA
(.alpha.=0.05) results were analyzed using Tukey's honestly
significant differences (HSD) or least significant differences
(LSD) where appropriate. Parametrical analysis using the Pearson
product moment correlation coefficient was employed to assess the
relationship between IAP levels and EDSS scores of MS patients.
Non-parametrical analysis using the Spearman rank correlation
coefficient was employed to assess the relationship between MS
disease subtype and EDSS scores. Normal subjects were included in
the analysis with an EDSS score of 0 indicative of normal
neurological function.
TABLE-US-00002 TABLE 2 Human Forward and Reverse Primer IAP and
Probe Sequences XIAP Forward 5'-GGT GAT AAA GTA AAG TGC TTT CAC
TGT-3' (SEQ ID NO: 1) Reverse 5'-TCA GTA GTT CTT ACC AGA CAC TCC
TCA A-3' (SEQ ID NO: 2) Probe 5'-(FAM)CAA CAT GCT AAA TGG TAT CCA
GGG TGC AAA TAT C(TAMRA)-3' (SEQ ID NO: 3) HIAP-1 Forward 5'-TGG
AGA TGA TCC ATG GGT TCA-3' (SEQ ID NO: 4) Reverse 5'-GAA CTC CTG
TCC TTT AAT TCT TAT CAA GT-3' (SEQ ID NO: 5) Probe 5'-(FAM)CTC ACA
CCT TGG AAA CCA CTT GGC ATG(TAMRA)-3' (SEQ ID NO: 6) HIAP-2 Forward
5'-TCT GGA GAT GAT CCA TGG GTA GA-3' (SEQ ID NO: 7) Reverse 5'-TGG
CCT TTC ATT CGT ATC AAG A-3' (SEQ ID NO: 8) Probe 5'-(FAM)CTC ACA
CCT TGG AAA CCA CTT GGC ATG(TAMRA)-3' (SEQ ID NO: 9) Survivin
Forward 5'-TCT GCT TCA AAG AGC TGG AA-3' (SEQ ID NO: 10) Reverse
5'-GAA AGG AAA GCG CAA CC G-3' (SEQ ID NO: 11) Probe 5'-(FAM)AGC
CAG ATG ACG ACC CCA TAG AGG AAC ATA(TAMRA)-3' (SEQ ID NO: 12) NAIP
Forward 5'-GCC ATT TTA TGT CCA AGG GAT ATC-3' (SEQ ID NO: 13)
Reverse 5'-CTT CCC AAT TTC CTA AAC ACT CA-3' (SEQ ID NO: 14) Probe
5'-(FAM)CTG TAC CGT GTC CTG TTT ACC TGT AAA GAC AAA GC(TAMRA)-3'
(SEQ ID NO: 15)
IV. Protein Purification, Protein Expression and Quantification
[0126] Results from our gene profiling studies were complimented
and cross-validated by determining whether there were corresponding
increases in the encoded proteins. In brief, T cells were isolated
by negative selection from 8 mL of blood as described above. T
cells and PBMN cells were lysed with radioimmunoprecipitation assay
(RIPA) lysis buffer with complete protease inhibitor (Roche) and
incubated on ice for 10 minutes. Cell lysates were centrifuged at
12000 rpm in an eppendorf microcentrofuge at 4.degree. C. for 20
minutes. The supernatant was extracted and transferred to a new
tube. Small aliquots (2 .mu.L) were used to determine protein
concentrations of the individual patient samples using the BCA
protein assay method (Pierce, Rockford, Ill., USA). Supernatants
were diluted 1:1 with 2.times. sodium dodecyl sulfate (SDS) sample
buffer with reducing agent dithiothreitol (DTT) (Sigma, D-9779) and
kept at -80.degree. C. until analyses.
[0127] Twenty .mu.g of protein was loaded on a 12% polyacrylamide
gel, separated by SDS-PAGE and transferred at 100 volts for 120
minutes to an Immobilin-P (polyvinylidene fluoride) membrane
(Millipore, Biorad Laboratories, Mississauga, Ontario, Canada).
Membranes were blocked for 2 hours at room temperature (RT) in 5%
skim milk powder in tris-buffered saline (TBS)/0.05%
polyoxyethylenesorbitan monolaurate (Tween-20) (Sigma, Canada).
Membranes were probed with XIAP (1:250; BD Pharminogen), HIAP-1
(1:250; BD Pharminogen), HIAP-2 (1:250; BD Pharminogen) or survivin
(1:250; Novus Biologicals) overnight at 4.degree. C. Membranes were
washed in TBS/0.05% Tween-20 and reprobed with an IgG anti-mouse
peroxidase (1:10 000) labeled antibody (Vector laboratories).
Chemiluminescence was detected by autoradiography with Hyperfilm
ECL.TM. high performance chemiluminescence film (Amersham Pharmacia
Biotech, England) and bands were quantified by analysis of scanned
images by Kodak 1D Scientific Imaging software (Kodak, USA).
Several film exposures were obtained for each protein investigated
to make certain that optical density signals were within a linear
range, permitting accurate quantification. Blots were then stripped
(Reblot, Chemicon) and reprobed for the endogenous control protein
.beta.-Actin (1:10 000; Sigma, Canada) to ensure equal protein
loading employing a peroxidase anti-mouse secondary antibody (1:10
000 Vector laboratories). Chemiluminescence was detected as
described above.
[0128] The optical density scores were subjected to a one-way ANOVA
assessing the relative protein expression of each of the IAPs in
the different MS patient groups (Benign, RRQ, RRA, SP, PP) and
normal controls. The optical density scores for the IAPs for RRMS
patients were assessed according to disease activity (active or
quiescent) at the time of blood draw. The inclusion of disease
activity was used to assess the protein expression profiles of the
IAPs from PBMN cells or T cells from RRMS patients to determine
whether the expression of specific proteins was related to disease
course. Individual group differences following significant ANOVA
(.alpha.=0.05) results were analyzed using Tukey's honestly
significant differences (HSD) or least significant difference (LSD)
multiple comparisons where appropriate. It should be mentioned that
although the aim of this investigation was to analyze 3 different
RNA preparations from the same subject (i.e. whole blood, PBMN
cells and T cells) along with the corresponding protein (PBMN cells
and T cells) most, but not all (-70%), patients are represented in
the three 3 types of RNA samples and 2 types of protein samples due
most commonly to low RNA and protein yields, especially with
respect to T cell samples.
Results
Patient Demographics and Past Clinical History
[0129] The Dalhousie Multiple Sclerosis Research Unit (DMSRU) is
the sole regional specialty clinic for MS in Nova Scotia and
maintains clinical records and a database on all patients seen
since 1979. The DMSRU database provides a detailed clinical history
of the majority of MS patients in Nova Scotia (Bhan et al., 2005)
permitting clinical features and biochemical markers (mRNA,
proteins) derived from blood samples to be correlated. Patients in
the present study first presented to the DSMRU as early as 1980.
All patients included in this study, presented to the DMSRU with a
RR, RR progressive or primary progressive disease activity. At this
time, patients with RR progressive or primary progressive disease
activity displayed higher scores on Kurtzke pyramidal (F(2,
94)=38.74, p<0.0001) and bowel and bladder scales (F(2,
94)=9.432, p<0.0001), while patients with primary progressive
disease activity also displayed elevated cerebellar symptom
contributions (F(2, 94)=3.162, p<0.05) relative to RR disease
course.
[0130] The presentation of neurological symptoms of patients
included in the present study were obtained from the DSMRU database
and revealed several specific clinical characteristics that
distinguished patients that come to display a progressive MS
disease course (SPMS and PPMS) from patients with present-day
benign, RRQ or RRA MS. Clinical histories of the various MS
patients revealed that patients that presented to the clinic with
pyramidal (F(4, 95)=8.576, p<0.0001) or bowel/bladder (F(4,
95)=3.53, p=0.01) dysfunction as measured by the Kurtzke pyramidal
or bowel and bladder score (0-6), indicative of motor cortical and
spinal cord deficits, would later develop a progressive disease
course (SP or PPMS). The frequency of initial symptom presentation
in patients that would be at the present date diagnosed with
benign, RRQ, RRA, SP or PP are as follows: Benign: frequent
presentation with brainstem (45%), cerebellar dysfunction (15%),
spinal cord (95%), cerebral-pyramidal symptoms (0%) and optic
neuritis (25%); RRQ: frequent presentation with brainstem (20%),
cerebellar dysfunction (20%), spinal cord (100%),
cerebral-pyramidal symptoms (0%) and optic neuritis (20%); RRA:
frequent presentation with brainstem (53%), cerebellar dysfunction
(0%), spinal cord (66%), cerebral-pyramidal symptoms (6%) and optic
neuritis (43%); SPMS: frequent presentation with brainstem (42%),
cerebellar dysfunction (29%), spinal cord (100%),
cerebral-pyramidal symptoms (9%) and optic neuritis (33%); PPMS:
frequent presentation with brainstem (33%), cerebellar dysfunction
(19%), spinal cord (96%), cerebral-pyramidal symptoms (4%) and
optic neuritis (30%).
Expanded Disability Status Scale (EDSS)
[0131] There was a strong correlation (r=0.833, p<0.0001)
between EDSS score and MS disease subtype. Patients with SPMS
(range 2.5 to 7.5) or PPMS (range 2 to 8.5) displayed higher EDSS
scores than patients with benign MS (range 0 to 3) or RRMS that
were categorized as either quiescent (range 1 to 6) or active
(range 1.5 to 6).
qRT-PCR
A. Whole Blood
[0132] There were no differences in XIAP (FIG. 1A), HIAP-1 (FIG.
2A), HIAP-2 (FIG. 3A), or survivin (FIG. 4A) mRNA levels in RNA
extracted from whole blood (ANOVA, p>0.05) among normal control
subjects (NS), or patients with benign, RRQ, RRA, SP or PPMS [XIAP
F (4, 66)=1.552, p=0.1974; HIAP-1 F (4, 70)>1, p=0.605, HIAP-2 F
(4, 69)=1.421, p=0.236, and survivin F (4, 61)=1.448, p=0.229,
respectively].
B. PBMN Cells
[0133] XIAP mRNA expression was increased approximately four and a
half-fold in PBMN cells from patients with RRA (n=10) or SPMS
(n=16) compared to NS (n=11), or patients with benign MS (n=8), RRQ
(n=10) or PPMS (n=12) [F (5, 61)=4.180, p<0.01]. There were no
differences in PBMN cell XIAP expression between NS or patients
with Benign, RRQ or PPMS (FIG. 1B). HIAP-1 expression in PBMN cells
was similar in NS (n=8) as well as in patients with Benign (n=10),
RR (n=16), SP (n=16) and PPMS (n=12) [F (4,57)=1.605, p=0.186]
(FIG. 2B). HIAP-2 expression was increased approximately two-fold
in PBMN cells from RRA (n=8) and SPMS patients (n=14) compared to
NS (n=10), and patients with benign (n=9) MS [F (5,57)=5.083,
p<0.001]. There were no differences in HIAP-2 PBMN mRNA levels
among RRQ (n=9) or PPMS (n=12) patients (FIG. 3B). There was a weak
positive correlation (r=0.310, p<0.05) between EDSS scores and
HIAP-2 mRNA levels in PBMN cells. Survivin PBMN cell mRNA levels
were the same in NS (n=6), patients with Benign (n=8), RR (n=16),
SP (n=12), and PPMS (n=6) [F (4,47)=1.655, p=0.178] (FIG. 46). NAIP
expression in PBMN cells was similar in normal control subjects
(n=7), or patients with Benign MS patients (n=10), qRRMS quiescent
(n=7), aRRMS (n=8), SPMS (n=14) or PPMS patients (n=9) [F
(5,50)<1, p=0.545], (FIG. 7B).
C. Resting T Cells
[0134] XIAP mRNA expression in resting T cells was similar in NS
(n=13) and patients with Benign (n=10), RR (n=17), SP (n=20) and
PPMS (n=17) [F (4,72)=1.433, p=0.232] (FIG. 1C). In contrast,
HIAP-1 mRNA expression was elevated approximately three-fold in
resting T cells from patients with RRMS irrespective of disease
activity (n=19) compared to NS (n=11) and patients with benign or
PPMS [F (4,77)=3.871, p<0.01] (FIG. 2C). There were no
differences in T cell HIAP-1 mRNA levels between patients with RRMS
and SPMS (n=22) (see FIG. 2C). In patients with RR (n=24) and SPMS
(n=20) HIAP-2 mRNA expression was increased approximately two and a
half-fold compared to NS (n=12) [F (4,81)=2.528, p<0.01]. There
were no differences in T cell HIAP-2 mRNA expression between
patients with benign MS (n=12) or PPMS (n=19) (FIG. 3C). Survivin T
cell mRNA expression was increased almost four and a half fold in
PPMS (n=18) relative to NS (n=10), patients with benign (n=7), RR
(n=15) and SPMS (n=17) [F (4,62)=4.271, p<0.01]. There was a
positive correlation (r=0.376; p<0.05) between the degree of
disability as reflected by EDSS scores and survivin mRNA expression
in T cells, (FIG. 4C). NAIP was also differentially increased in
resting T cells of a small subset of PPMS patients. At this
juncture, however, it is not clear what the increase in NAIP
represents.
[0135] Table 3 summarizes the relationships between IAP expression
patterns, immune cell subtype and multiple sclerosis subtype. The
arrows (1) indicate an increase in the IAP expression relative to
control subjects.
TABLE-US-00003 TABLE 3 MS Subtype Whole blood PBMN cells Resting T
cells Benign No change No change No change RRMSQ .uparw. NAIP No
change .uparw. HIAP-1 RRMSA .uparw. NAIP .uparw. XIAP, .uparw.
HIAP-2 .uparw. HIAP-1, .uparw. HIAP-2 SPMS .uparw. NAIP .uparw.
XIAP, .uparw. HIAP-2 .uparw. HIAP-2 PPMS No change No change
.uparw. Survivin
[0136] Expression patterns of the IAPs in whole blood, PBMNs and T
cells distinguish subtypes of MS. IAPs were not elevated in
patients with benign MS. Patients with RRMS, RRMS or SPMS displayed
elevated levels of NAIP in whole blood. Patients with relapse
remitting MS that were quiescent (RRMSQ) displayed elevated HIAP-1
in resting T cells. By contrast, patients with relapse remitting MS
that were in the active state (RRMSA) displayed elevated XIAP and
HIAP-2 in PBMNs and elevated HIAP-1 and HIAP-2 in resting T cells.
The same changes occurred in patients with secondary progressive MS
(SPMS) with the exception that only HIAP-2 was elevated in resting
T cells. Lastly, patients with primary progressive MS (PPMS) only
displayed elevated survivin expression in resting T cells. Survivin
up-regulation is often observed in many forms of cancer suggestive
of increased resistance to apoptosis and elevated high
proliferative status.
Western Blotting
[0137] XIAP PBMN cell optical density (55 kDa band) was increased
approximately two and a half-fold in PBMN cells from patients with
RRA (n=12) or SPMS (n=15) compared to NS (n=13), or patients with
PPMS (n=10) [F (5,65)=5.207, p<0.001]. There were no differences
in PBMN cell XIAP expression between NS or patients with Benign,
RRQ or PPMS (FIG. 5). Quantification of the HIAP-1 band (72 kDa)
revealed a 1.5 fold elevation of this protein from extracts from T
cells of patients with RRMS irrespective of disease activity
(combined RRQ and RRA) relative to other groups [F94, 56)=6.144,
p<0.001] (FIG. 6). The results obtained by western blotting were
therefore consistent with those obtained by qRT-PCR.
Discussion
[0138] The present invention demonstrates that distinct patterns of
elevated IAP expression (XIAP, HIAP-1, HIAP-2, survivin) in PBMN
cells and resting T cells are associated with different types of
MS. This finding is consistent with the proposal that MS is not a
single clinical entity but rather a heterogeneous disorder. Our
findings suggest that distinct apoptotic mechanisms are activated
in different populations of immune cells in patients with various
forms of MS. Furthermore, our results are consistent with the
hypothesis that increased IAP expression may contribute to the
pathogenesis of MS by delaying the removal of auto-reactive immune
cells by apoptosis [Sharief and Semra 2001; Semra et al. 2002]
thereby preventing the death of myelin-reactive immune cells
resulting in inflammation and demyelination in the brain and spinal
cord.
[0139] In the present investigation, XIAP mRNA and protein was
differentially increased in PBMN cell fractions with no notable
differences among groups of MS patients in whole blood or T cells.
Increased PBMN cell expression of XIAP was noted in RRMS patients
with a more active disease course as well as among patients with
SPMS. Monocytes comprise about 3-8% of the leukocytes in the blood.
It is therefore tempting to speculate that monocytes contribute to
the elevation of XIAP mRNA and protein observed in patients with
aggressive forms of MS. XIAP is expressed in normal monocytes but
relatively undetectable in granulocytes. Moreover, exaggerated
monocyte XIAP expression is associated with acute myeloid leukemia
that has a poor clinical outcome [Tamm et al. 2000]. Neutrophils
are the primary immune cell subtype in whole blood comprising up to
approximately 70% of leukocytes present in whole blood. Neutrophils
can regulate suppressor T cell responses to myelin [Zehntner at al.
2005b], have been associated with demyelinated plaques in a mouse
model of experimental autoimmune encephalomyelitis [Tsunoda et al.
2000] and promote demyelination [Gaupp at al. 2003].
Calpain-mediated degradation of XIAP is though to play a critical
role in controlling the number of circulating neutrophils
[Kobayashi et al. 2002] while the ability of the bacterium
Anaplasma phagoctophilium to delay neutrophil apoptosis is
associated with reduced degradation of XIAP [Ge and Rikihisa 2006].
XIAP was not increased in whole blood of MS patients relative to
normal control subjects although several patients with benign, RR,
SP and PP MS demonstrated values that were greater than controls.
These results suggest that at least as far as XIAP, HIAP-1 and
HIAP-2 are concerned; the resistance of neutrophils to apoptosis
does not play a major role in MS. The relative lack of XIAP mRNA
induction in whole blood was not due to an overall decrease in T
cell numbers or a reduced percentage of T cells in whole blood in
MS patients as levels of XIAP mRNA in subsequent resting T cell
fractions from the same patients were unremarkable. The lack of
increased XIAP mRNA expression in T cells in patients with
aggressive forms of MS contrasts with the report by Sharief and
Semra [2001] in which elevated XIAP protein levels were observed in
mitogen activated T cells isolated from RRMS patients relative to
normal and neurological control subjects. One explanation for this
discrepancy between the results of the present study and those of
Sharief and Semra [2001] is that we examined levels of XIAP mRNA in
resting T cells while levels of XIAP protein in mitogen activated T
cells were examined in the former. In MS, T cells may be primed by
PHA stimulation resulting in elevated XIAP expression.
[0140] The increase in XIAP, HIAP-1 and HIAP-2 in mitogen activated
immune cells [Sharief et al. 2002b], while supporting a role for
impaired activation-induced apoptosis in the immune cells of MS
patients, may simply be an exaggeration of the immune cells
sensitized to myelin antigens and thus more likely to display
elevated IAP levels upon stimulation with PHA. Consistent with this
notion, our inability to detect elevated XIAP levels in resting T
cells from MS patients suggests that mitogen stimulation
artificially activates a survival pathway by mechanisms not
relevant to MS. In further support of this hypothesis,
mitogen-stimulated apoptosis in non-myelin reactive CD4+ and CD8+ T
cells has been reported to be comparable in MS patients and normal
control subjects while activation of myelin-reactive CD4+ and CD8+
T cells was associated with decreased Fas associated apoptosis in
MS patients [Saresella et al. 2005; Zang et al. 1999]. The
demonstration that XIAP is increased in resting PBMN cells in the
present study suggests that these cells have been stimulated with
MS relevant antigens in the peripheral blood circulation such as
myelin basic protein or myelin oligodendrocyte glycoprotein,
inducing differentiation and prolonging their lifespan. Although
monocytes, B lymphocytes and T lymphocytes compose the cell types
present in the PBMN cell fraction, the increase in XIAP expression
was not present in T cell fractions, thus implicating either B
lymphocytes or monocytes as the major contributor to increases in
this apoptotic gene. While evidence for increased XIAP levels in B
lymphocytes in MS is lacking, the contribution of XIAP expression
in B lymphocytes to the overall increase in PBMN cell XIAP in
patients with RRMS and SPMS cannot be dismissed entirely. In humans
XIAP, HIAP-1 and HIAP-2 mRNAs are strongly expressed in B
lymphocytes of normal subjects as well as in patients with B-cell
chronic lymphocytic leukemia as measured by RNAse protection assay
[Munzert et al. 2002]. Still, monocytes have an important role in
the pathogenesis of MS and are one of the primary cell types
responsible for tissue damage [van der Goes et al. 2005]. Yet, it
has previously been demonstrated in monocytes derived from normal
subjects that differentiation induction and clonal expansion led to
an upregulation of XIAP protein, an effect not observed in
neutrophils, contributing to increased longevity of cells derived
from the monocyte lineage while treatment with XIAP antisense
oligonucleotides resulted in significant loss of cell viability
[Miranda et al. 2003]. XIAP, HIAP-1 and HIAP-2 mRNA is expressed in
neutrophils albeit the relative protein expression is low. Yet
stimulation of neutrophils with lipopolysaccharide (LPS) of
gram-negative bacteria induces upregulation of HIAP-1 and HIAP-2
mRNA. Moreover, in septic patients characterized by infection of
the bloodstream by toxin-producing bacteria, delayed neutrophil
apoptosis has been associated with increased XIAP mRNA expression
with no changes observed in HIAP-1 or HIAP-2 mRNA expression in
patients possibly contributing to the persistence of an
inflammatory reaction [O'Neill et al. 2004]. The lack of XIAP,
HIAP-1 and HIAP-2 in neutrophils of MS patients relative to
mitogen-induced IAP and reduced neutrophil apoptosis in septic
patients demonstrates the diversity of the immune cells involved in
differential immune perturbations and outlines the specificity of
inflammatory events underlying MS pathology. Taken together, while
neutrophils may characterize more acute peripheral inflammatory
conditions, increased expression of monocytes displaying
exaggerated XIAP mRNA levels suggest that these cell types play a
major role in more aggressive types of MS, characterized by
widespread tissue damage and marked neurological disability.
[0141] Expression of HIAP-1 and HIAP-2 appear to be more tissue
specific than XIAP [Liston et al. 2003; Vischioni at al. 2006].
Highest levels of HIAP-1 and HIAP-2 are found in tissues of
lymphoid origin including the thymus, peripheral lymphocytes and
spleen [Vischioni et al. 2006]. Both HIAP-1 and HIAP-2 have CARD
domains and are involved in the inactivation of caspase 9 [Reed at
al. 2003]. Through homotypic protein-protein interactions CARD
domains are thought to influence function of inflammatory and
apoptotic signaling pathways [Reed at al. 2003]. HIAP-1 and HIAP-2
mRNA is increased in T cells in MS patients that are experiencing
relapses/remissions and/or disease progression, respectively
suggesting a prominent role for inflammatory T cells in the
pathogenesis of RRMS disease progression reminiscent of data
previously reported by Sharief et al. in mitogen stimulated T
cells. Moreover, it has been revealed that the phenotypic profile
of immune cell types differs in patients in early MS at least as
far as in patients that have experienced a clinically isolated
syndrome. Patients with active MRI activity in the proceeding year
displayed distinct changes in peripheral lymphocyte subsets
relative to MRI-inactive patients that were predictive of MRI
activity in early disease. Interestingly, it has been reported that
infiltrating and clonally expanded autoreactive T cells persisted
for longer than 7 years in the CSF and blood of patients with RRMS,
irrespective of interferon-.beta. (IFN-.beta.) treatment history,
which does not eliminate autoreactive T cells, contributing to the
propensity of increased clinical exacerbations and possibly the
eventual progression of neural disability [Skulina et al. 2004].
While clonal expansion of auto-reactive T cells have been
identified in the blood and CSF of normal subjects, these cell
populations are susceptible to apoptosis [Skulina et al. 2004],
while myelin-primed T cells in MS are resistant to programmed cell
death proliferating and inducing CNS damage [Pender 1998]. In the
present investigation, increased expression of the anti-apoptotic
genes HIAP-1 and HIAP-2 in RRMS and SPMS would render the cells
apoptosis-resistant, increasing their life-span and contributing to
myelin destruction at the very least during the relapse phase. The
sole increase in HIAP-1 mRNA levels in unstimulated T cells is
consistent with a critical role for this population of immune cells
in MS. The differential expression of IAPs suggests cell-type
specific apoptotic pathways and redundancy in the immune system
such that defects in one pathway will not abolish apoptosis
altogether.
[0142] The gene expression pattern of HIAP-2 within immune cells
isolated from MS patients differed slightly from the pattern of
expression observed for HIAP-1. Elevated PBMN cell HIAP-2
expression was found in patients with RRA and SPMS likely
reflecting a contribution from T cells. HIAP-2 expression was
increased in T cells in patients with RRA and SPMS, but not
subjects with benign or PPMS, suggesting that the increased
expression of this anti-apoptotic gene in T cells is associated
with a clinical course characterized by either relapses and
remission or an unrelenting disease progression. Benign MS patients
can convert to RRA and SPMS with time, and increased IAP levels
within specific immune cell populations may have prognostic value
indicative of a change in MS disease course prior to the
reappearance of symptoms. In summary, XIAP, HIAP-1 and HIAP-2
displayed cell specific induction patterns among patients with
different subtypes and severity of RRMS that may perpetuate the
continuous phasic presentation of inflammation and resolution
within the CNS.
[0143] Survivin is a unique member of the IAP family implicated in
both cell proliferation and apoptosis [Ambrosini et al. 1997]. The
survivin pathway interfaces with both the cell-death machinery and
mechanisms of cell-cycle progression and microtubule stability,
specifically expressed during the G2/M phase of the cell cycle.
Survivin expression is undetectable in most normal adult tissues
[Fukuda and Pelus 2001] including PBMN cells, T cells and
whole-blood cell lysates, but is over expressed in virtually every
human tumor that has been studied [Ouhtit 2007]. Survivin
expression was relatively undetectable in whole blood, PBMN cells
or resting T lymphocytes in NS and patients with benign, RR and
SPMS, reminiscent of the findings of Sharief and Semra [Livak and
Schmittgen 2001]. Although several RRMS and SPMS patients with
elevated EDSS scores demonstrated increased survivin levels in
whole blood and PBMN cells suggestive of active inflammatory
disease these increases were not associated with a specific MS
disease subtype. It should be mentioned that although survivin mRNA
levels were low or undetectable in most normal and benign MS blood
samples, detectable levels of survivin expression have been
previously reported in normal peripheral lymphocytes [Shinozawa et
al. 2000] that are upregulated during clonal expansion of these
cells as well as non-malignant T cells increasing their resistance
to apoptosis [Sharief and Semra 2001]. In comparison, mitogen
activation of T cells in culture elevated survivin expression may
be associated with clonal expansion as reported by Sharief and
Semra [Sharief et al. 2002a] and therefore may simply reflect cell
proliferation and not apoptotic status. Survivin expression prior
to T cell activation was undetectable, while increased survivin
expression was found in memory T cells following stimulation with
PHA in lymphocytes isolated from normal donors [Kornacker et al.
2001]. Indeed, survivin is now believed to regulate chromosome
segregation during mitosis [Fukuda and Pelus 2001]. In the present
study, the scattered increase in survivin expression in whole-blood
and PBMN cells may be indicative of cells undergoing division and
proliferation at the time of blood draw, although the correlation
of survivin levels with EDSS disability may be of pathogenic
significance in MS, at the very least allowing prolonged immune
cell viability, proliferation and ultimately contributing to CNS
damage and clinical disability.
[0144] It should be underscored; however, that in the present
study, PPMS patients displayed survivin levels approximately 5 fold
higher in resting T cells relative to NS, benign, RR and SPMS.
Primary progressive MS has been associated with a specific
polymorphism of the cytotoxic T-lymphocyte antigen 4 gene, that
down-regulates T-cell function [Maurer et al. 2002]. In contrast, a
small portion of T cells with elevated survivin would be expected
to reduce T-cell elimination producing a more prolonged disease
time-course. It is notable that survivin, a marker and potential
target for the treatment of cancer therapy is upregulated in a type
of MS for which there is no effective treatment As a result,
survivin may hold diagnostic utility for distinguishing SPMS and
PPMS in patients for which a clear clinical history is
unavailable.
[0145] Neuronal apoptosis inhibitory protein (NAIP) like XIAP,
human IAP-1 (HIAP-1) and human IAP-2 (HIAP-2) possesses 3 BIR
domains, while survivin possesses 1 BIR domain, that support the
suppression of caspase 3 and 7; the two most potent effector
caspases NAIP, unlike the other IAPs, has a NACHT domain and
proteins of the NACHT family may serve as critical pathogen sensing
and signal transducing molecules within the innate immune system.
In contrast to XIAP, HIAP-1, or HIAP-2 expression in whole blood,
NAIP mRNA expression (FIG. 7A) was increased approximately two to
three-fold elevation of NAIP mRNA in the whole blood from patients
with qRRMS (n=9), aRRMS (n=11), SPMS (n=14), PPMS (n=8) relative to
patients with Benign MS (n=8) or healthy subjects (n=14) [F (5,
59)=1.947, p=0.1]. There was a moderate positive correlation
(r=0.368, p<0.01) between EDSS disability and NAIP mRNA
expression in whole blood. There were no difference between whole
blood NAIP expression between normal subjects (n=14) or patients
with Benign MS (n=8). Neutrophils are the primary immune cell
subtype in the PBMN fraction that comprise up to approximately 70%
of leukocytes present in whole blood. Neutrophils can regulate
suppressor T cell responses to myelin, have been associated with
demyelinated plaques in a mouse model of experimental autoimmune
encephalomyelitis and promote demyelination. Calpain-mediated
degradation of XIAP is though to play a critical role in
controlling the number of circulating neutrophils while the ability
of the bacterium Anaplasma phagoctophilium to delay neutrophil
apoptosis is associated with reduced degradation of XIAP. However,
XIAP is not increased in whole blood.
[0146] One unexpected observation was the differential expression
of NAIP within whole blood. Regarding NAIP expression in patients
within the different sub-types of MS, NAIP was differentially
increased, unlike the other IAPs in which the increase was
restricted to a specific cell fraction, in both whole blood of
patients with RRMS and SPMS. Interestingly, NAP is increased in
whole blood but not PBMN cell mRNA of patients with RR and SPMS.
The difference in the expression of NAIP mRNA in whole blood
compared to PBMN cell fractions likely reflects the increased
number of granulocytes or dendritic cells in whole blood, cells in
low levels or relatively absent in PBMN cell fractions. NAIP
possess a NACHT NTPase domain that codes for proteins involved in
intracellular pathogen sensing and regulation of the innate immune
response and inflammation. It is of note that NACHT gene mutations
have been associated with inflammatory bowel disease, suggesting a
prominent role of NACHT proteins in deterring pathogens from the
gut. The NACHT domain is also present in those proteins involved in
Major Histocompatability Complex (MHC) type II antigen
transcription. MHC II antigens are present on dendritic cells,
macrophages and neutrophils, the major antigen presenting cells
(APC) involved in the innate immune response, representing the
initial line of defense against foreign pathogens, present in whole
blood. In RR and SP MS patients experiencing relapses, NAIP may
increase the lifespan of APC such as neutrophils. Gene and protein
expression of HIAP-1, HIAP-2 and XIAP are found in neutrophils,
although at relatively low levels compared to NAIP and survivin.
Monocytes in whole blood can differentiate into phagocytotic
macrophages or dendritic cells (DCs). DCs are antigen-presenting
leukocytes that function to initiate the immune response by
activating T-lymphocytes and stimulating the secretion of
cytokines. In this regard, DCs stimulate an immune response that
may be prolonged by the extended survival of DCs by blocking DC
apoptosis. In normal subjects, less than 0.1% of circulating
leukocytes are immature DCs. Mature DCs are localized in lymphoid
tissues. However, among individuals with RR, SP and PP MS
circulating dendritic cells secreting pro-inflammatory cytokines
are increased relative to normal control subjects that are thought
to reflect a prominent role of DCs in MS disease pathogenesis.
Under basal states of inactivation, NAIP is strongly expressed in
immature DCs, while HIAP-1, HIAP-2 are rather weakly expressed, and
XIAP and survivin are not expressed at all. Upon activation with
antigen and subsequent maturation, NAIP expression was down
regulated while levels of XIAP, HIAP-1 and HIAP-2 gene expression
increased. Survivin levels remained undetectable. Bcl-2 and Bcl-xL,
members of the Bcl-2 family of anti-apoptotic genes, were not or
rather weakly expressed, in DCs, respectively. Although Bcl-2
protein levels are high in resting T lymphocytes, the expression of
Bcl-2 protein was similarly expressed in basal and cultured T cells
activated with PHA among normal subjects and corresponding patients
with RRMS. In humans, NAIP mRNA levels are low while XIAP, HIAP-1
and HIAP-2 mRNAs are strongly expressed in B lymphocytes of normal
subjects. NAIP gene expression appears to be regulated by different
factors than HIAP-1, HIAP-2, XIAP, survivin and the Bcl-2 family.
The increase of NAIP expression in whole blood likely reflects
increased survival of immune cells involved in inflammatory
processes and myelin damage as reflected by increased EDSS
scores.
[0147] In the mouse, NAIP is highly expressed in macrophages. NAIP
is increased in macrophages in mice in response to infection with
an intracellular pathogen (Legionella pneumophila) that causes
Legionnaire's disease, an acute form of pneumonia, in humans. While
the success of Legionella pneumophila infection is dependant upon
macrophage apoptosis, inducible NAIP expression within macrophages
serves a protective role by inhibiting caspase 3 activities thus
increasing the lifespan of the cell. Monocytes, macrophages,
neutrophils and dendritic cells secrete pro-inflammatory cytokines
that are associated with the inflammatory relapse phase of
relapsing-remitting forms of MS. It is not clear at this juncture
whether the increase NAIP expression in sub-types of MS with a
prominent inflammatory response dictates specific immune cell
contributions to the heterogeneous subtypes of MS, defining
inflammatory and non-inflammatory conditions. Yet, neutrophil
apoptosis regulation during an immune-mediated inflammatory
response plays a key role in its resolution. Neutrophils are
activated following release of pro-inflammatory cytokines,
including IL-1, IL-6, tumor necrosis factor .alpha. and interferon
.gamma. that also serve to inhibit apoptotic death. Increase of
NAIP in whole blood RNA from RR and SPMS patients, suggests that
over expression of NAIP may prolong neutrophils-induced
inflammatory response which may be the basis for the correlation of
NAIP in whole blood with EDSS scores, akin to the response of
macrophages to infection with Legionella pneumophila associated
with the relapse phase of the disease underlying extensive myelin
damage. Increased expression of NAIP in inflammatory neutrophils
would prevent their apoptotic deletion and delay resolution of
acute MS symptomatology.
CONCLUSIONS
[0148] Taken together, the present findings indicate that specific
patterns of IAP expression in distinct populations of immune cells
have potential diagnostic and prognostic value for MS. To
recapitulate, high levels of XIAP and HIAP-2 expression in PBMN
cells and HIAP-2 in T cells may be associated with aggressive forms
of this disorder (RRA and SPMS) characterized by inflammation that
are best managed through early intervention. In contrast, XIAP,
HIAP-1 and HIAP-2 expression in immune cell subsets is not elevated
in benign and primary progressive forms of MS that do not do not
require treatment or do not respond to current disease modifying
therapies, respectively. In patients with PPMS, elevated expression
of survivin may provide a novel therapeutic target for this
devastating form of MS in which there are no current treatments. In
addition to the prognostic value of IAP expression within distinct
cell populations, our findings suggest that apoptotic dysregulation
of potentially autoreactive immune cells in MS occurs through
multiple immune pathways involving cells of both the innate (PBMN
cells) and the adaptive (T cells) immune systems. The over
expression of IAPs increase the resistance of specific cell types
to apoptosis that contribute to the various subtypes of MS. It is
of note that pre-clinical studies with the XIAP anti-sense molecule
(data not shown) demonstrate that decreasing levels of XIAP in the
immune system reduce symptom severity in an animal model of MS
[Zehntner et al. 2005a]. Preliminary studies in cancer patients
suggest that this compound has clinical efficacy suggesting that
such a compound may represent a novel treatment for other diseases
where impaired apoptosis has been implicated such as MS. In
conclusion, basal expression patterns of several IAPs in specific
immune cell populations not only reflect the diverse range of
apoptotic mechanisms involved in MS pathogenesis but may have
diagnostic utility in distinguishing between various subtypes of MS
and serve as potential drug targets for different forms of this
autoimmune disorder.
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Other Embodiments
[0219] From the foregoing description, it will be apparent to one
of ordinary skill in the art that variations and modifications may
be made to the invention described herein to adapt it to various
usages and conditions. Such embodiments are also within the scope
of the present invention.
[0220] All publications mentioned in this specification are hereby
incorporated by reference.
Sequence CWU 1
1
15127DNAArtificial SequenceOligonucleotide chain 1ggtgataaag
taaagtgctt tcactgt 27228DNAArtificial SequenceOligoncleotide chain
2tcagtagttc ttaccagaca ctcctcaa 28334DNAArtificial
SequenceOligonucleotide chain 3caacatgcta aatggtatcc agggtgcaaa
tatc 34421DNAArtificial SequenceOligonucleotide chain 4tggagatgat
ccatgggttc a 21529DNAArtificial SequenceOligonucleotide chain
5gaactcctgt cctttaattc ttatcaagt 29627DNAArtificial
SequenceOligonucleotide chain 6ctcacacctt ggaaaccact tggcatg
27723DNAArtificial SequenceOligonucleotide chain 7tctggagatg
atccatgggt aga 23822DNAArtificial SequenceOligonucleotide chain
8tggcctttca ttcgtatcaa ga 22927DNAArtificial
SequenceOligonucleotide chain 9ctcacacctt ggaaaccact tggcatg
271020DNAArtificial SequenceOligonucleotide chain 10tctgcttcaa
agagctggaa 201118DNAArtificial SequenceOligonucleotide chain
11gaaaggaaag cgcaaccg 181230DNAArtificial SequenceOligonucleotide
chain 12agccagatga cgaccccata gaggaacata 301324DNAArtificial
SequenceOligonucleotide chain 13gccattttat gtccaaggga tatc
241423DNAArtificial SequenceOligonucleotide chain 14cttcccaatt
tcctaaacac tca 231535DNAArtificial SequenceOligonucleotide chain
15ctgtaccgtg tcctgtttac ctgtaaagac aaagc 35
* * * * *