Vascular Epigenome Dynamics in African-American Hypertensives

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DESCRIPTION (provided by applicant): Hypertension is the most common modifiable risk factor that leads to the major causes of death and disability in the US. It is a complex, heritable disease of multi-factorial etiology that involves the interactions between environmental factors and multiple genetic susceptibility alleles. It is postulated that the high prevalence and more virulent course of hypertensive vascular disease among African-Americans reflects a critical interplay between genes and environment that is mediated by the vascular epigenome. The pathogenesis of hypertension-induced vascular complications (e.g. stroke) involves long-term changes in vessel function and structure. However, the molecular mechanisms of vascular 'memory' that govern these chronic changes remain poorly defined. Our central hypothesis poses that the chronic maintenance and progressive nature of vascular disease in hypertension is mediated by dynamic changes in the vascular epigenome that promote the selective up-regulation of a "vasculopathic" gene expression profile as well as the coordinate repression of intrinsic "vasculo-protective" genes. The proposed project will utilize genome-wide, deep sequencing technology to characterize a topographical map of DNA and histone methylation marks associated with changes in the hypertensive vascular transcriptome as well as define the dynamic response of the vascular epigenome to therapeutic interventions. We will test several related hypotheses: " There is a distinctive 'molecular signature' of the vascular transcriptome and a corresponding epigenomic pattern of DNA and histone methylation that is characteristic of the microvasculature of African-Americans with hypertension compared to age-matched African-American controls without hypertension. " The clinical efficacy of pharmacologic blockade of angiotensin II in the treatment of hypertension is mediated in part by its distinctive, dynamic effects on the epigenomic pattern of DNA and histone methylation and its consequent influence on the vascular transcriptome. " The blood pressure lowering efficacy of the DASH diet is mediated by specific, nutrient-responsive elements in the vascular epigenome and its consequent effects on the vascular transcriptome. Overall, this project holds promise for creating a unique Epigenomic Data Resource and a novel integration of genetics, epigenetic, nutrigenomics and pharmacogenomics in a common, clinically significant disease that contributes to racial/ethnic disparities in cardiovascular health. It is anticipated that these studies will yield novel insights and new drug discovery paradigms for the treatment of hypertension. Public Health Relevance: High blood pressure affects 1 in 3 adults in the US and is a major cause of strokes and heart attacks. It involves the interplay between genetic predisposition and external factors such as diet (e.g. high salt intake). The pathways that mediate the long-term effects of diet on the function of the blood vessel are unknown. This project will test the hypothesis that the expression of genes that promote or protect individuals from hypertension is modulated by epigenetic marks or codes that are responsive to changes in dietary nutrients.