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Title: Apolipoprotein
biopolymer markers indicative of insulin resistance
United States Patent: 7,314,762
Issued: January 1, 2008
Inventors: Jackowski;
George (Kettleby, CA), Marshall; John (Toronto, CA)
Assignee: Nanogen, Inc. (San
Diego, CA)
Appl. No.: 09/993,366
Filed: November 21, 2001
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Pharm Bus Intell
& Healthcare Studies
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Abstract
The instant invention involves the use of
a combination of preparatory steps in conjunction with mass spectroscopy
and time-of-flight detection procedures to maximize the diversity of
biopolymers which are verifiable within a particular sample. The cohort of
biopolymers verified within such a sample is then viewed with reference to
their ability to evidence at least particular disease state; thereby
enabling a diagnostician to gain the ability to characterize either the
presence or the absence of at least one disease state relative to
recognition of the presence and/or the absence of the biopolymer, predict
disease risk assessment, and develop therapeutic avenues against the
disease.
Description of the
Invention
SUMMARY OF THE INVENTION
The instant invention is characterized by the use of a combination of
preparatory steps, e.g. chromatography and 1-D tricine polyacrylamide gel
electrophoresis. Subsequent to which the gel is stained, e.g. with
Coomasie blue, silver or rubidium. Next, bands are selected from the gels
for further study. Tryptic digestion of each band follows, concluding with
the extraction of tryptic peptides from the digest. This extraction may be
accomplished utilizing C18 ZIPTIPs, or organic extract and dry technique
followed by MALDI Qq TOF (Maldi Quadrupole Quadrupole Time of Flight)
processing.
Additional methodologies may include SELDI MS, 2-D gel technology, MALDI
MS/MS and time-of-flight detection procedures to maximize the diversity of
biopolymers which are verifiable within a particular sample. The cohort of
biopolymers verified within a sample is then compared to develop data
indicating their presence, absence or relative strength/concentration in
disease vs normal controls, and further studied to determine whether the
up-regulation or down-regulation of a single biopolymer or group of
biopolymers is indicative of a disease state or predictive of the
development of said disease state. Additionally, biopolymers recognized as
being indicative or predictive of a disease state in accordance with the
instant invention are useful in therapeutic intervention, e.g. as
therapeutic modalities in their own right, in the course of therapeutic
target recognition, in the development and validation of efficacious
therapeutic modalities, e.g when interrogating or developing phage display
libraries, and as ligands or receptors for use in conjunction with
therapeutic intervention.
Although all manner of biomarkers related to all disease conditions are
deemed to be within the purview of the instant invention and methodology,
particular significance was given to those markers and diseases associated
with the complement system, cognitive diseases, e.g. Alzheimer's disease
and Syndrome X and diseases related thereto.
The complement system is an important part of non-clonal or innate
immunity that collaborates with acquired immunity to destroy invading
pathogens and to facilitate the clearance of immune complexes from the
system. This system is the major effector of the humoral branch of the
immune system, consisting of nearly 30 serum and membrane proteins. The
proteins and glycoproteins composing the complement system are synthesized
largely by liver hepatocytes. Activation of the complement system involves
a sequential enzyme cascade in which the proenzyme product of one step
becomes the enzyme catalyst of the next step. Complement activation can
occur via two pathways: the classical and the alternative. The classical
pathway is commonly initiated by the formation of soluble antigen-antibody
complexes or by the binding of antibody to antigen on a suitable target,
such as a bacterial cell. The alternative pathway is generally initiated
by various cell-surface constituents that are foreign to the host. Each
complement component is designated by numerals (C1-C9), by letter symbols,
or by trivial names. After a component is activated, the peptide fragments
are denoted by small letters. The complement fragments interact with one
another to form functional complexes. Ultimately, foreign cells are
destroyed through the process of a membrane-attack complex mediated lysis.
The C4 component of the complement system is involved in the classical
activation pathway. It is a glycoprotein containing three polypeptide
chains (.alpha., .beta., and .gamma.). C4 is a substrate of component C1s
and is activated when C1s hydrolyzes a small fragment (C4a) from the amino
terminus of the .alpha. chain, exposing a binding site on the larger
fragment (C4b).
The native C3 component consists of two polypeptide chains, .alpha. and
.beta.. As a serum protein, C3 is involved in the alternative pathway.
Serum C3, which contains an unstable thioester bond, is subject to slow
spontaneous hydrolysis into C3a and C3b. The C3f component is involved in
the regulation required of the complement system which confines the
reaction to designated targets. During the regulation process, C3b is
cleaved into two parts: C3bi and C3f. C3bi is a membrane-bound
intermediate wherein C3f is a free diffusible (soluble) component.
Complement components have been implicated in the pathogenesis of several
disease conditions. C3 deficiencies have the most severe clinical
manifestations, such as recurrent bacterial infections and immune-complex
diseases, reflecting the central role of C3. The rapid profusion of C3f
moieties and resultant "accidental" lysis of normal cells mediated thereby
gives rise to a host of auto-immune reactions. The ability to understand
and control these mechanisms, along with their attendant consequences,
will enable practitioners to develop both diagnostic and therapeutic
avenues by which to thwart these maladies.
In the course of defining a plurality of disease specific marker
sequences, special significance was given to markers which were
evidentiary of a particular disease state or with conditions associated
with Syndrome-X. Syndrome-X is a multifaceted syndrome, which occurs
frequently in the general population. A large segment of the adult
population of industrialized countries develops this metabolic syndrome,
produced by genetic, hormonal and lifestyle factors such as obesity,
physical inactivity and certain nutrient excesses. This disease is
characterized by the clustering of insulin resistance and hyperinsulinemia,
and is often associated with dyslipidemia (atherogenic plasma lipid
profile), essential hypertension, abdominal (visceral) obesity, glucose
intolerance or noninsulin-dependent diabetes mellitus and an increased
risk of cardiovascular events. Abnormalities of blood coagulation (higher
plasminogen activator inhibitor type I and fibrinogen levels),
hyperuricemia and microalbuminuria have also been found in metabolic
syndrome-X.
The instant inventors view the Syndrome X continuum in its cardiovascular
light, while acknowledging its important metabolic component. The first
stage of Syndrome X consists of insulin resistance, abnormal blood lipids
(cholesterol, triglycerides and free fatty acids), obesity, and high blood
pressure (hypertension). Any one of these four first stage conditions
signals the start of Syndrome X.
Each first stage Syndrome X condition risks leading to another. For
example, increased insulin production is associated with high blood fat
levels, high blood pressure, and obesity. Furthermore, the effects of the
first stage conditions are additive; an increase in the number of
conditions causes an increase in the risk of developing more serious
diseases on the Syndrome X continuum.
A patient who begins the Syndrome X continuum risks spiraling into a maze
of increasingly deadly diseases. The next stages of the Syndrome X
continuum lead to overt diabetes, kidney failure, and heart failure, with
the possibility of stroke and heart attack at any time. Syndrome X is a
dangerous continuum, and preventative medicine is the best defense.
Diseases are currently most easily diagnosed in their later stages, but
controlling them at a late stage is extremely difficult. Disease
prevention is much more effective at an earlier stage.
In a further contemplated embodiment of the invention, samples may be
taken from a patient at one point in time, as a single sample or as
multiple samples, or at different points in time such that analysis is
carried out on multiple samples for ongoing analysis. Typically, a first
sample is taken from a patient upon presentation with possible symptoms of
a disease and analyzed according to the invention. Subsequently, some
period of time after presentation, for example, about 3-6 months after the
first presentation, a second sample is taken and analyzed according to the
invention. The data can be used, by way of example, to diagnose or monitor
a disease state, determine risk assessment, identify therapeutic avenues,
or determine the therapeutic value of an agent such as a pharmaceutical.
Subsequent to the isolation of particular disease state marker sequences
as taught by the instant invention, the promulgation of various forms of
risk assessment tests are contemplated which will allow physicians to
identify asymptomatic patients before they suffer an irreversible event
such as diabetes, kidney failure, and heart failure, and enable effective
disease management and preventative medicine. Additionally, the specific
diagnostic tests which evolve from this methodology provide a tool for
rapidly and accurately diagnosing acute Syndrome X events such as heart
attack and stroke, and facilitate treatment.
More particularly, biopolymer markers elucidated via methodologies of the
instant invention find utility related to broad areas of disease
therapeutics. Such therapeutic avenues include, but are not limited to:
1) utilization and recognition of said biopolymer markers, variants or
moieties thereof as direct therapeutic modalities, either alone or in
conjunction with an effective amount of a pharmaceutically effective
carrier;
2) validation of therapeutic modalities or disease preventative agents as
a function of biopolymer marker presence or concentration;
3) treatment or prevention of a disease state by formation of disease
intervention modalities; e.g. formation of biopolymer/ligand conjugates
which intervene at receptor sites to prevent, delay or reverse a disease
process;
4) use of biopolymer markers or moieties thereof as a means of elucidating
therapeutically viable agents, e.g. from a bacteriophage peptide display
library, a bacteriophage antibody library or the like;
5) instigation of a therapeutic immunological response; and
6) synthesis of molecular structures related to said biopolymer markers,
moieties or variants thereof which are constructed and arranged to
therapeutically intervene in the disease process.
A process for identifying or developing therapeutic avenues related to a
disease state utilizing any of the above examples may follow results
obtained from conducting an analysis inclusive of interacting with a
biopolymer including the sequence of the particular disease specific
marker or at least one analyte thereof of the present invention. Such
treatment or prevention of a disease state by formation of disease
intervention modalities may be by the formation of biopolymer/ligand
conjugates which intervene at receptor sites to prevent, delay, or reverse
a disease process. In addition, a means of elucidating therapeutically
viable agents may include the use of a bacteriophage peptide display
library or a bacteriophage antibody library. The therapeutic avenues may
regulate the presence or absence of the biopolymer including the sequence
of the particular disease specific marker or at least one analyte thereof
in the present invention.
Accordingly, it is an objective of the instant invention to define a
disease specific biopolymer marker sequence which is useful in evidencing
and categorizing at least one particular disease state.
It is an additional objective of the instant invention to develop methods
and means of disease therapy, including but not limited to:
1) utilization and recognition of said biopolymer markers, variants or
moieties thereof as direct therapeutic modalities, either alone or in
conjunction with an effective amount of a pharmaceutically effective
carrier;
2) validation of therapeutic modalities or disease preventative agents as
a function of biopolymer marker presence or concentration;
3) treatment or prevention of a disease state by formation of disease
intervention modalities; e.g. formation of biopolymer/ligand conjugates
which intervene at receptor sites to prevent, delay or reverse a disease
process;
4) use of biopolymer markers or moieties thereof as a means of elucidating
therapeutically viable agents, e.g. from a bacteriophage peptide display
library, a bacteriophage antibody library or the like;
5) instigation of a therapeutic immunological response; and
6) synthesis of molecular structures related to said biopolymer markers,
moieties or variants thereof which are constructed and arranged to
therapeutically intervene in the disease process, e.g. by directly
determining the three-dimensional structure of said biopolymer marker
directly from an amino acid sequence thereof.
It is another objective of the instant invention to evaluate samples
containing a plurality of biopolymers for the presence of disease specific
biopolymer marker sequences (disease specific markers) which evidence a
link to at least one specific disease state.
It is a further objective of the instant invention to elucidate
essentially all biopolymeric markers, moieties or variants thereof
contained within said samples, whereby particularly significant moieties
may be identified.
It is a further objective of the instant invention provide at least one
purified antibody which is specific to said disease specific marker
sequence.
It is yet another objective of the instant invention to teach a monoclonal
antibody which is specific to said disease specific marker sequence.
It is a still further objective of the invention to teach polyclonal
antibodies raised against said disease specific marker.
It is yet an additional objective of the instant invention to teach a
diagnostic kit for determining the presence, concentration, or relative
strength/concentration of said disease specific marker.
It is a still further objective of the instant invention to teach methods
for characterizing disease state based upon the identification of said
disease specific marker.
DETAILED DESCRIPTION OF THE INVENTION
In earlier work, for example in U.S. patent application Ser. No.
09/846,330 filed Apr. 30, 2000, the contents of which is herein
incorporated by reference, raw sera was obtained and mixed with formic
acid and extracted the peptides with C18 reversed phase ZIPTIPs.
In the instantly disclosed invention, we deal with proteins generally
having a molecular weight of about 20 kD or more. In general, proteins of
greater than 20 kD can reliably be fragmented by trypsin or other enzymes.
The instant technology incorporates sufficient sensitivity to deal with
even the low production of peptides from proteins less than 20 kD clipped
from gel.
Proteins differ from peptides in that they cannot be effectively resolved
by time of flight MS and they are too large (>3 kD) to be effectively
fragmented by collision with gases. The most commonly used solution to
these problems is to resolve the proteins by polyacrylamide gel
electrophoresis followed by staining with silver, or coomasie brilliant
blue or rubidium dyes or counter staining with Zinc-SDS complexes. Once
the proteins have been resolved and visualized with stains the proteins
that differ between disease states can then be excised from the gel and
the protein purified in the 1-D gel band or 2-D gel spot can be cleaved
into fragments less that 3 kD by proteolytic enzymes. Once protein has
been resolved by gel and cleaved by enzymes, the protein is considered in
the form of peptides and therefore can be dealt with as per earlier work
(09/846,330). The peptide is either collected and purified with C18
reversed phase chromatography or by some other form of chromatography
prior to reversed phase separation. The peptide can also be collected in
ammonium carbonate buffer that is subsequently evolved by reaction with
acid or by removal in organic solvents.
Once the peptides are collected they can be sequenced, e.g. with a
MALDI-Qq-TOF but also with a TOF-TOF, and ESI-Q-TOF or an ION-TRAP. Other
types of MS analysis which may be employed are SELDI MS and MS/MS. The
peptides are fragments of the original protein. The peptides are sequenced
by fragmentation to produced a spectrum composed of the parts of the
peptide. The peptide fragments can be produced by a strong ionization
energy with a laser, temperature, electron capture, collision between the
peptides themselves or with other objects such as gas molecules. The
spacing in terms of mass between the parts of the peptides is a
fragmentation pattern. The fragmentation pattern of each peptide from the
starting mass to the last remaining amino acid (from either end) is
unique.
The human genome contains the genes that encode all proteins. The
proteolytic cut sites within all these proteins can be predicted from the
translated amino acid sequence. The mass of the peptides that result from
the predicting cut sites can be calculated. Similarly, the fragmentation
pattern from each hypothetical peptide can be predicted. Thus, we can
conceptually digest the proteins within the human proteome and fragment
them.
When a peptide has been "sequenced" it is understood that the peptide
fragment has been purified by one of the methods above, i.e. Time of
flight (TOF) or by chromatography, before fragmenting it with gas to
produce the peptide fragments. The original peptide mass and fragmentation
pattern obtained is then fit to those from the theoretical digestion and
fragmentation of the genome. The peptide that best matches the theoretical
peptides and fragments and is biologically possible, i.e. a potential
human blood-borne protein, is thus identified. It is possible to identify
plural targets in this fashion.
Claim 1 of 8 Claims
1. An isolated biopolymer
marker consisting of SEQ ID NO:1 indicative of insulin resistance
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patent.
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