Identifying Epigenetic Biomarkers of Cardiovascular Disease Risk In Humans

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DESCRIPTION (provided by applicant): Cardiovascular disease (CVD) is the largest single contributor to global mortality and appears to dominate mortality trends in the future. New evidence is emerging that inflammation attributable to monocytes/macrophages contributes to the development of CVD. Traditional CVD risk factors, such as insulin resistance, hyperlipidemia, and smoking, have been associated with modification of epigenetic markers and signatures of epigenetic dysregulation can be detected in peripheral blood samples. Monocytes (CD14+CD16+) residing in peripheral blood from dialysis patients predicted cardiovascular disease incidence, implicating this cell type in disease pathology. Indeed, an increased percentage of CD14+CD16+ monocytes were observed in the blood of patients with coronary heart disease. An increased percentage of these monocytes were also observed in the blood of HIV+ patients. Data from our collaborators indicate that monocytes from persons with HIV infection are hyper-responsive to oxidized LDL or LPS, producing high levels of IL-1�, IL6 and IL8. Thus, HIV-mediated immune activation in monocytes may play a role in the development of CVD. In support of this link, our preliminary data demonstrate that monocytes from HIV+ individuals, who have an elevated risk for CVD, also exhibit hyper-responsiveness to inflammatory stimuli. Interestingly, we observed that the level of a specific epigenetic mark, DNA methylation, at the promoter region of a pro- inflammatory gene in part explained the varying degree to which monocytes from individuals with clinically determined "low" or "high" risk for CVD responded to inflammatory stimuli. The mechanistic link between monocyte inflammation and CVD risk may be fundamental, but more easily detectable in individuals with heightened inflammatory response, such as those infected with HIV. This proposal will therefore test the hypothesis that a heightened inflammatory response elicited by monocytes confers an increased risk to CVD due to epigenetic dysregulation of environmentally labile loci, including at pro-inflammatory genes. This may be independent of HIV infection status. To address this hypothesis, we aim to evaluate monocyte inflammatory response in banked blood specimens from HIV-infected and matched uninfected individuals selected based on clinical parameters of CVD risk, and characterize, compare, and integrate this data with genome-wide DNA methylation and gene expression profiles from these monocytes. Collectively, this unique clinical, immunological, and epigenomic database will allow us to identify novel biomarkers associated with CVD risk that may enable improved risk stratification strategies for cardiovascular disease. (End of Abstract)