
We
collaborate extensively with a variety of research groups at Dartmouth
and around the world. Our primary NIH-funded research projects
are summarized below.
I. Bioinformatics Strategies for Biodefense Vaccine Research
This project is funded by a 5-year grant from the National Institute of Allergy and Infectious Disease (NIH R01 AI59694, PI - Moore) with annual direct costs of approximately $350,000/year.
The
identification of biomarkers of adverse events following smallpox vaccination is
important for public health and bioterrorism defense. Fortunately, we now have the ability to
measure massive amounts of genetic, genomic, and proteomic information. Our ability to use this information to
facilitate the identification of biomarkers of adverse events will largely
depend on the architecture of the genotype-to-phenotype relationship. The process of innate and adaptive immunity
is a complex trait that involves many biochemical and physiological pathways and
thus many interacting genes. The
complexity of the genotype-phenotype relationship suggests that we need a
research strategy that embraces, rather than ignores, complexities due to
gene-gene (GxG) and gene-environment (GxE) interactions. We are developing and evaluating a
comprehensive bioinformatics strategy for identifying combinations biomarkers of
adverse events following vaccination for bioterrorism agents. The bioinformatics strategy combines new and
novel statistical and computational methods for detecting GxG and GxE
interactions with knowledge about hierarchical biological systems. This strategy
is being developed and evaluated using simulated data as well as genetic and
proteomic data available from more than 100 volunteers that are part of an ongoing
NIAID/NIH-sponsored trial to evaluate the Aventis Pasteur Smallpox Vaccine
(APSV). Software packages for all
methods are being developed and will be made available to the research
community.
II. Genetic Architecture of Plasma t-PA and PAI-1
This project was funded by a 5-year grant from the National Heart Lung and Blood Institute (NIH R01 HL65234, PI - Moore) with annual direct costs of approximately $250,000/year.
Arterial
thrombosis is the proximate cause of events in patients with ischemic
cardiovascular disease. A major risk
factor for thrombosis is alteration of the balance between tissue-type
plasminogen activator (t-PA) and plasminogen activator inhibitor type 1 (PAI-1),
two components of the fibrinolytic system.
Understanding the role of genetic variation in determining plasma t-PA
and PAI-1 levels, their variability, and their co-variability will improve our
ability to identify those at risk and will facilitate the development of new
prevention and treatment strategies. We
have selected two genes from the fibrinolytic system (t-PA
and PAI-1)
and four genes from the renin-angiotensin system (angiotensinogen
(AGT),
renin
(REN),
angiotensin
converting enzyme
(ACE)
and
angiotensin II receptor type 1
(AT-1)
as candidates for influencing plasma t-PA and PAI-1 levels, their variability,
and their co-variability based on the biology of these genes and because our
preliminary studies demonstrate an interaction between the two systems. We have established two large
population-based samples of human subjects to document the genetic architecture
of plasma t-PA and PAI-1. The first
sample consists of approximately 8500 Caucasians from the Prevention of REnal
and Vascular ENd-stage Disease (PREVEND) study in Groningen, The
Netherlands. The second sample consists
of more than 2500 Blacks from Ghana, Africa ascertained through our study site
in the regional capital of Sunyani. We
are utilizing these two population-based resources to identify the functional
variations in the fibrinolytic and renin-angiotensin system genes that influence
plasma t-PA and PAI-1 levels, variability, and
co-variability.
III. Genetic Basis of Trauma Recovery
This project is funded by a 5-year grant from the National Institute of Child Health and Human Development (NIH R01 HD047447, PI - Moore) with annual direct costs of approximately $370,000/year.
All
people, regardless of ethnicity, education, or socioeconomic status, are
susceptible to trauma. Recovery from
trauma is highly variable and there are currently no good predictors of who is
likely to recover and respond to rehabilitation. A major factor influencing recovery and
rehabilitation is the development of Adult Respiratory Distress Syndrome (ARDS)
or Acute Lung Injury (ALI). The goal of
this study is to identify genetic polymorphisms that predict who will develop
ARDS or ALI following trauma. We
have ascertained more than 1000 subjects from Nashville, TN that have
been admitted to the intensive care unit at Vanderbilt University
Medical Center following traumatic injury. We are focusing on
candidate genes for ARDS/ALI that are involved in nitric oxide
production, vascular resistance, cellular responses to injury, cellular
signaling, and alveolar function. This
study will capitalize on expertise in trauma medicine, biochemical and molecular
genetics, statistical genetics, and bioinformatics to provide a comprehensive
approach to the identification of genetic predictors of trauma recovery and
rehabilitation.
IV. Machine Learning Prediction of Cancer Susceptibility
This new project is funded by a 4-year grant from the National Library of Medicine (NIH R01 LM009012, PI - Moore) with annual direct costs of approximately $200,000/year.
Susceptibility to sporadic forms of cancer is determined by
numerous genetic factors that interact in a nonlinear manner in the context of
an individual’s age and environmental exposure.
This complex genetic architecture has important implications for the use
of genome-wide association studies for identifying susceptibility genes. The assumption of a simple architecture
supports a strategy of testing each single-nucleotide polymorphism (SNP)
individually using traditional univariate statistics followed by a correction
for multiple tests. However, a complex
genetic architecture that is characteristic of most types of cancer requires
analytical methods that specifically model combinations of SNPs and environmental
exposures. While new and novel methods
are available for modeling interactions, exhaustive testing of all combinations
of SNPs is not feasible on a genome-wide scale because the number of
comparisons is effectively infinite.
Thus, it is critical that we develop intelligent strategies for
selecting subsets of SNPs prior to combinatorial modeling. Our objective is to develop a research
strategy for the detection, characterization, and interpretation of gene-gene
and gene-environment interactions in a genome-wide association study of bladder
cancer susceptibility. To accomplish
this objective, we will develop and evaluate modifications and extensions to
the ReliefF algorithm for selecting or filtering subsets of single-nucleotide
polymorphisms (SNPs) for multifactor dimensionality reduction (MDR) analysis of
gene-gene and gene-environment interactions (AIM 1). We will develop and evaluate a stochastic
wrapper or search strategy for MDR analysis of interactions that utilizes
ReliefF values as a heuristic (AIM 2). The
filter approach will be statisyically compared to the wrapper approach. The best ReliefF strategies will be provided
as part of our open-source MDR software package (AIM 3). Finally, we will apply the best ReliefF-MDR
analysis strategy to the detection, characterization, and interpretation of
gene-gene and gene-environment interactions in a large genome-wide association
study of bladder cancer susceptibility (AIM 4).
The methods developed here will be applied to nearly 1500 haplotype
tagging SNPs (tagSNPs) across approximately 500 cancer susceptibility genes
measured in 542 subjects with bladder cancer and 745 healthy controls
ascertained as part of a large epidemiological study from the state of New
Hampshire.
Last updated by JHM on March 2, 2008