Gene Expression and Thrombosis in a Community Based Cohort Study

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Recent data suggest that patients with both acute and chronic cardiovascular disease (CVD) have not only enhanced platelet function, but also increased interactions between platelets and the inflammatory process. Platelets lead to acute thrombotic occlusion and also contribute to the chronic process of atherosclerosis. Whereas established risk factors, inflammatory and thrombotic biomarkers, and genotypic variations have been examined extensively to predict CVD events, methods utilizing gene expression profiles have not been reported from large population-based studies. In preliminary hospital-based data, we found distinct patterns of platelet gene expression in patients with CVD including enhanced expression of the inflammatory Toll receptors and 5-lipoxygenase. Importantly, these proteins all stimulate the pro- inflammatory NFkappa-B signaling pathway that leads to expression of specific pro-inflammatory and thrombotic genes. Expression of the NFkappa-B dependent genes cyclooxygehase 2 and interleukin 6 were also found to be increased. Previously, we have measured systemic biomarkers of vascular inflammation in the community-based sample of 3500 middle-aged and elderly men and women of the Framingham Heart Study (FHS) Offspring Study. In these subjects, inflammatory biomarkers were related to traditional CVD risk factors, and prevalent clinical and subclinical CVD. However, a large proportion of the variability in vascular disease and thrombosis remains unexplained and the contribution of gene expression from circulating peripheral cells is unknown. The central hypothesis of this proposal is that increased thrombotic and inflammatory pathways specifically mediated by NFkappa-B are a pro-atherothrombotic phenotype and can be measured as enhanced gene and biomarker expression due to NFkappa-B dependent activity. We hypothesize that the expression of these genes is itself a proatherosclerotic phenotype that is influenced by both environmental factors and genetic variability. We propose the following questions: 1. Is stimulation of the NFkappa-B pathway associated with increased expression of relevant markers of enhanced thrombosis and inflammation? 2. What is the relation between NFkappa-B dependent expression (RNA) and the relevant genotypes(DNA)? 3. Do established CVD risk factors correlate with NFkappa-B dependent changes in platelet and leukocyte gene expression in community-based individuals? 4. Do changes in gene expression in platelets and leukocytes predict subclinical and clinical CVD?