Texas A&M University College Station - Medicine
University of Pennsylvania
Texas A&M University
Philadelphia
•Proteomic analysis of nitration and chlorination of tyrosine on HDL particles.\n•Lipidomic analysis of phospholipid loss in HDL particles.\n•Demonstrated a correlation between lipid oxidative stress and protein misfolding.
Senior Research Assistant
University of Pennsylvania
University of Pennsylvania Health System
St. George's University
Grenada
Philadelphia
•Developed novel small molecule mass spectrometric assays to quantify lipid oxidative stress.\n•Used this technique to determine that Amyloid protein functions as an oxidant and antioxidant.\n•Refined solubilization techniques for MALDI analysis of modified
misfolded and insoluble proteins.\n•Novel biochemical/ mass spectrometric studies of the role of hydroxy-2-nonenal in protein misfolding.\n•Funded by private and NIH grants demonstrating effective research
communication and writing skills.\n•Managed laboratory equipment and supply budgets.
Research Associate
University of Pennsylvania Health System
University of Pennsylvania
•Identified structural regions of synuclein protein misfolding using circular dichroism and infrared spectroscopy.\n•Analyzed proteins using dialysis
HPLC
immunoprecipitation
electrophoresis
Western blots and ELISAS.\n•Conducted DNA analyses including cloning
agarose gel electrophoresis
and southern blots analysis.\n•Prepared
grew
harvested
affinity purified and tested polyclonal and monoclonal antibodies.\n•Analyzed antibodies via biacore analysis and immunohistochemistry.
University of Pennsylvania
Assistant Professor
•Identified amyloid plaques using a novel metal-based probe and a novel antibody method. Pioneered and published a unifying hypothesis for amyloid diseases
including linking metabolic diseases and Alzheimer’s disease. Managed a $400K total budget and a team of up to 8.\n•Mechanistically linked metabolic dysfunction and amyloid protein misfolding in Alzheimer’s disease (Fawver
Hall JAD 2012) and Type 2 Diabetes (manuscript in preparation). \n•Hypothesized that amyloids can function as sensors of dysfunction (Petrofes Chapa 2012).\n•Drug screening: screened anti- amyloid and antioxidant drugs for potential therapeutic use in Alzheimer’s disease (Fawver
Duong JAD 2012).\n•Identified post-translational oxidation/glycation modifications of Amyloid β.(Murray 2007
Ellis 2010)\n•Identified a novel metal based probe for imaging amyloid plaques in tissue sections and in vivo. (Cook 2012 in press)\n•Development of LCMS (QTRAP) methods to identify small compounds and lipids
and MALDI TOF identification of posttranslational modification (including protelytic digests and sequencing).\n•Taught medical histology to medical students.\n•Implemented several changes in the histology course- including 5 self-study video modules and reformatting review sessions to Jeopardy game format. These changes
studies over a 3 year period from 2010
resulted in a significant increase in student exam scores.
Texas A&M Health Science Center
Russian
Spanish
English
French
Hillview
Postdoctoral Training
Neuroscience
University of Pennsylvania School of Medicine
McGill University
Merck
McGill University
Merck
Montreal
Canada Area
•Pulmonary resistance & compliance screen for agents blocking arachidonic acid & leukotriene B pathways.
Research Technician
Taught physiology to medical students in the fall and spring (~1500/year with a very high student evaluation)\nDirector of Medical School Research Institute (MSRI) 2014-2019 (~50-100 students/year)\nProgram Director for Medical School Assessment Program (MSAP): an online admissions course.\n\nMy strengths also include:\n•> 12 years in medical education\n• > 19 years of demonstrated research experience in neuroscience;\n• > 6 years research experience in diabetes and obesity;\n•Analytical
innovative
visionary
and critical thinker; skilled at problem finding and problem solving;\n•Skilled in establishing research programs
leading projects
and laboratory management;\n•Effective early and rapid screening of existing drugs to avoid unnecessary lengthy clinical trials;\n•Have demonstrated both the ability to mentor and offer conflict resolution strategies;\n•Providing multiple opportunities to develop the strengths of junior researchers;\n•Developed a network of academic and biotech collaborations.\n\nTechnical Skills\n•Antibodies:Production
purification
conjugation. Antigenic epitope identification
and mapping. immunization. Biacore
ELISA
and RIA. \n•Biochemistry: Lipid extraction and purification. Protein expression
characterization
and purification.\n•Biophysics: UV-Vis
Fluorescence
FTIR spectroscopy
Circular dicroism.\n•Cell culture: Mammalian cells
primary fibroblasts
primary preadipocytes
cell transformation
hybridomas\nChromatography: FPLC
HPLC
ion exchange
gel filtration
reversed phase
HPLC
TLC\n•Gel electrophoresis: Western Blot
Filter trap
RIA
ELISA
IP
and co-IP.\nMass spectrometry: GC/MS
LCMS (LTQ
QTrap 2000)
MALDI (Voyager MALDI-TOF
QSTAR
4700 TOF/TOF).\n•Histochemistry: Colorimetric
fluorescence.\n•Microscopy: Electron
fluorescence
light.\n•Transgenic models: Transgenic animal models: Mouse
C. elegans.
St. George's University
Grenada
Doctor of Philosophy (Ph.D.)
•Initiated animal model studies to characterize Acylation Stimulating Proteins function.\n•Developed in-house methods to measure postprandial lipid and glucose metabolism in mice and cell culture.
Obesity
Diabetes
McGill University
Pioneer Hi-Bred
•Performed Agrobacterium mediated transformation and shoot regeneration of Canola.\n•Contracted for PCR RAPD (polymorphism) screening of tomato hybrid seed purity.\n•Developed a 96 well Mini-DNA extraction method for tomato leaf tissue samples.
Research Technician
Ontario
Canada
Pioneer Hi-Bred
Houston
Texas Area
Associate Professor nontenure
Texas A&M University
Bachelor of Science (B.Sc.)
Biology/Biological Sciences
General
University of Waterloo
Physiology
Physiology
Coursera
Using Python to Access Web Data
TYENCH2UAPAF
Using Databases with Python
3933WZ68S6RR
Coursera
Physiology
Experimental Design
Neuroscience
Higher Education
Online courses
Teaching Classes
Education
Histology
Human Physiology
Train Employees
Health Education
Meta-analysis
Cell Physiology
Manage Complex Projects
Cardiac physiology
Teaching
Muscle Physiology
Systematic Reviews
Cardiovascular Physiology
Medical Education
Ruthenium red colorimetric and birefringent staining of amyloid beta aggregates in vitro and in Tg2576 mice
Alzheimer’s disease (AD) is a devastating neurodegenerative disease most notably characterized by the misfolding of amyloid-β (Aβ) into fibrils and its accumulation into plaques. In this Article
we utilize the affinity of Aβ fibrils to bind metal cations and subsequently imprint their chirality to bound molecules to develop novel imaging compounds for staining Aβ aggregates. Here
we investigate the cationic dye ruthenium red (ammoniated ruthenium oxychloride) that binds calcium-binding proteins
as a labeling agent for Aβ deposits. Ruthenium red stained amyloid plaques red under light microscopy
and exhibited birefringence under crossed polarizers when bound to Aβ plaques in brain tissue sections from the Tg2576 mouse model of AD. Staining of Aβ plaques was confirmed via staining of the same sections with the fluorescent amyloid binding dye Thioflavin S. In addition
it was confirmed that divalent cations such as calcium displace ruthenium red
consistent with a mechanism of binding by electrostatic interaction. We further characterized the interaction of ruthenium red with synthetic Aβ fibrils using independent biophysical techniques. Ruthenium red exhibited birefringence and induced circular dichroic bands at 540 nm upon binding to Aβ fibrils due to induced chirality. Thus
the chirality and cation binding properties of Aβ aggregates could be capitalized for the development of novel amyloid labeling methods
adding to the arsenal of AD imaging techniques and diagnostic tools.
Ruthenium red colorimetric and birefringent staining of amyloid beta aggregates in vitro and in Tg2576 mice
Neuronal and oligodendrocytic aggregates of fibrillar alpha-synuclein define several diseases of the nervous system. It is likely that these inclusions impair vital metabolic processes and compromise viability of affected cells. Here
we report that a 12-amino acid stretch ((71)VTGVTAVAQKTV(82)) in the middle of the hydrophobic domain of human alpha-synuclein is necessary and sufficient for its fibrillization based on the following observations: 1) human beta-synuclein is highly homologous to alpha-synuclein but lacks these 12 residues
and it does not assemble into filaments in vitro; 2) the rate of alpha-synuclein polymerization in vitro decreases after the introduction of a single charged amino acid within these 12 residues
and a deletion within this region abrogates assembly; 3) this stretch of 12 amino acids appears to form the core of alpha-synuclein filaments
because it is resistant to proteolytic digestion in alpha-synuclein filaments; and 4) synthetic peptides corresponding to this 12-amino acid stretch self-polymerize to form filaments
and these peptides promote fibrillization of full-length human alpha-synuclein in vitro. Thus
we have identified key sequence elements necessary for the assembly of human alpha-synuclein into filaments
and these elements may be exploited as targets for the design of drugs that inhibit alpha-synuclein fibrillization and might arrest disease progression.
A Hydrophobic stretch of 12 amino acid residues in the middle of alpha-synuclein is essential for filament assembly
lycation is the reaction of a reducing sugar with proteins and lipids
resulting in myriads of glycation products
protein modifications
cross-linking
and oxidative stress. Glycation reactions are also elevated during metabolic dysfunction such as in Alzheimer's disease (AD) and Down's syndrome. These reactions increase the misfolding of the proteins such as tau and amyloid-β (Aβ)
and colocalize with amyloid plaques in AD. Thus
glycation links metabolic dysfunction and AD and may have a causal role in AD. We have characterized the reaction of Aβ with reactive metabolites that are elevated during metabolic dysfunction. One metabolite
glyceraldehyde-3-phosphate
is a normal product of glycolysis
while the others are associated with pathology. Our data demonstrates that lipid oxidation products malondialdehyde
hydroxynonenal
and glycation metabolites (methylglyoxal
glyceraldehyde
and glyceraldehyde-3-phosphate) modify Aβ42 and increase misfolding. Using mass spectrometry
modifications primarily occurred at the amino terminus. However
the metabolite methylglyoxal modified Arg5 in the Aβ sequence. 4-Hydroxy-2-nonenal modifications were similar to our previous publication. To place such modifications into an in vivo context
we stained AD brain tissue for endproducts of glycation
or advanced glycation endproducts (AGE). Similar to previous findings
AGE colocalized with amyloid plaques. In summary
we demonstrate the glycation of Aβ and plaques by metabolic compounds. Thus
glycation potentially links metabolic dysfunction and Aβ misfolding in AD
and may contribute to the AD pathogenesis. This association can further be expanded to raise the tantalizing concept that such Aβ modification and misfolding can function as a sensor of metabolic dysfunction.
Amyloid beta (β) metabolite sensing: biochemical linking of glycation modification and misfolding.
http://www.ncbi.nlm.nih.gov/pubmed/22330832
Amyloids as sensors and protectors (ASAP) hypothesis.
Aggregated alpha-synuclein proteins form brain lesions that are hallmarks of neurodegenerative synucleinopathies
and oxidative stress has been implicated in the pathogenesis of some of these disorders. Using antibodies to specific nitrated tyrosine residues in alpha-synuclein
we demonstrate extensive and widespread accumulations of nitrated alpha-synuclein in the signature inclusions of Parkinson's disease
dementia with Lewy bodies
the Lewy body variant of Alzheimer's disease
and multiple system atrophy brains. We also show that nitrated alpha-synuclein is present in the major filamentous building blocks of these inclusions
as well as in the insoluble fractions of affected brain regions of synucleinopathies. The selective and specific nitration of alpha-synuclein in these disorders provides evidence to directly link oxidative and nitrative damage to the onset and progression of neurodegenerative synucleinopathies.
Oxidative damage linked to neurodegeneration by selective alpha-synuclein nitration in synucleinopathy lesions
Acylation stimulating protein (ASP) is a potent stimulator of triglyceride synthesis in adipocytes. In the present study
we have examined the effect of an ASP functional knockout (ASP(-/-)) on lipid metabolism in male mice. In both young (14 weeks) and older (26 weeks) mice there were marked delays in postprandial triglyceride clearance (80% increase at 14 weeks and 120% increase at 26 weeks versus wild type (+/+)). Postprandial nonesterified fatty acids were also increased in ASP(-/-) mice versus ASP(+/+) mice by 37% (low fat 10% Kcal) and by 73% (high fat 40% Kcal) diets
although there were no differences in fasting lipid levels. The ASP(-/-) mice had moderately increased energy intake (16% +/- 2% p < 0.0001) and reduced feed efficiency (33% increase in calories/g of body weight gained on low fat diet) versus wild type. The ASP(-/-) mice also had modest changes in insulin/glucose metabolism (30% to 40% decrease in insulin.glucose product)
implying increased insulin sensitivity. As well
there were decreases in leptin (29% shift in leptin to body weight ratio) and up to a 26% decrease in specific adipose tissue depots versus the wild type mice on both low fat and high fat diets. These results demonstrate that ASP plays an important role in adipose tissue metabolism and fat partitioning.
Acylation stimulating protein (ASP) deficiency alters postprandial and adipose tissue metabolism in male mice
Alzheimer's disease (AD) is a devastating neurodegenerative disease with pathological misfolding of amyloid-β protein (Aβ). The recent interest in Aβ misfolding intermediates necessitates development of novel detection methods and ability to trap these intermediates. We speculated that two regions of Aβ may allow for detection of specific Aβ species: the N-terminal and 22-35
both likely important in oligomer interaction and formation. We determined via epitomics
proteomic assays
and electron microscopy that the Aβ42 species (wild type
ΔE22
and MetOx) predominantly formed fibrils
oligomers
or dimers
respectively. The 2H4 antibody to the N-terminal of Aβ
in the presence of 2% SDS
primarily detected fibrils
and an antibody to the 22-35 region detected low molecular weight Aβ species. Simulated molecular modeling provided insight into these SDS-induced structural changes. We next determined if these methods could be used to screen anti-Aβ drugs as well as identify compounds that trap Aβ in various conformations. Immunoblot assays determined that taurine
homotaurine (Tramiprosate)
myoinositol
methylene blue
and curcumin did not prevent Aβ aggregation. However
calmidazolium chloride trapped Aβ at oligomers
and berberine reduced oligomer formation. Finally
pretreatment of AD brain tissues with SDS enhanced 2H4 antibody immunostaining of fibrillar Aβ. Thus we identified and characterized Aβs that adopt specific predominant conformations (modified Aβ or via interactions with compounds)
developed a novel assay for aggregated Aβ
and applied it to drug screening and immunohistochemistry. In summary
our novel approach facilitates drug screening
increases the probability of success of antibody therapeutics
and improves antibody-based detection and identification of different conformations of Aβ.
Probing and trapping a sensitive conformation: amyloid beta fibrils
oligomers
and dimers
Alzheimer's disease (AD) is thought to start years or decades prior to clinical diagnosis. Overt pathology such as protein misfolding and plaque formation occur at later stages
and factors other than amyloid misfolding contribute to the initiation of the disease. Vascular and metabolic dysfunctions are excellent candidates
as they are well-known features of AD that precede pathology or clinical dementia. While the general notion that vascular and metabolic dysfunctions contribute to the etiology of AD is becoming accepted
recent research suggests novel mechanisms by which these/such processes could possibly contribute to AD pathogenesis. Vascular dysfunction includes reduced cerebrovascular flow and cerebral amyloid angiopathy. Indeed
there appears to be an interaction between amyloid β (Aβ) and vascular pathology
where Aβ production and vascular pathology both contribute to and are affected by oxidative stress. One major player in the vascular pathology is NAD(P)H oxidase
which generates vasoactive superoxide. Metabolic dysfunction has only recently regained popularity in relation to its potential role in AD. The role of metabolic dysfunction in AD is supported by the increased epidemiological risk of AD associated with several metabolic diseases such as diabetes
dyslipidemia and hypertension
in which there is elevated oxidative damage and insulin resistance. Metabolic dysfunction is further implicated in AD as pharmacological inhibition of metabolism exacerbates pathology
and several metabolic enzymes of the glycolytic
tricarboxylic acid cycle (TCA) and oxidative phosphorylation pathways are damaged in AD. Recent studies have highlighted the role of insulin resistance
in contributing to AD. Thus
vascular and metabolic dysfunctions are key components in the AD pathology throughout the course of disease. The common denominator between vascular and metabolic dysfunction emerging from this review appears to be oxidative stress and Aβ. ..
Vascular and metabolic dysfunction in Alzheimer’s disease: A review.
Ian
Murray
Texas A&M Health Science Center
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