Nuclear Mechanisms of VSMC Gene Regulation and Cellular Interactions in Diabetes

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DESCRIPTION (provided by applicant): Cardiovascular complications such as hypertension and atherosclerosis are highly prevalent in the diabetic population. Evidence supports a role for genes associated vascular inflammation in the pathogenesis of diabetic vascular disease. However, very little is known about the subtle molecular mechanisms or key nuclear factors involved in regulating these genes in vascular smooth muscle cells (VSMC), or their in vivo functional relevance. Recent studies show that diabetic vascular complications continue to progress in patients who have not had prior intensive glycemic control. Based on our new supportive data, we propose that novel "epigenetic" chromatin remodeling mechanisms of gene regulation in vascular cells may mediate this "diabetic memory" phenomenon. Our data also demonstrate that genes activated in VSMC under diabetic conditions in vitro or vivo via these nuclear mechanisms can lead to close interactions between VSMC and monocytes in the subendothelial space. Our central hypothesis is that diabetic stimuli such as high glucose (HG) and advanced glycation end products (AGEs) induce inflammatory chemokines and cytokines in VSMC via novel in vivo nuclear chromatin remodeling mechanisms. These factors can induce vascular inflammation, VSMC-monocyte interactions and phenotypic changes and thereby lead to accelerated cardiovascular disease. Specific Aim 1 is to examine the nuclear transcriptomic mechanisms by which diabetic stimuli lead to chemotactic gene expression in VSMC. Here we will determine the nuclear interplay between NF-kB transcription factor and key chromatin factors using gain- and loss-of-function approaches. Specific Aim 2 is to evaluate the in vivo relevance of these nuclear mechanisms and factors in VSMC and aortas derived from mouse models of diabetes. Here we will determine the potential association with hyperglycemic memory, sustained gene expression and activation observed in these diabetic cells. Specific Aims 3 and 4 are to determine the functional impact of diabetic and atherosclerotic conditions, and these chromatin changes in leading to vascular dysfunction by promoting heterotypic interactions between VSMC and monocytes in vitro and in the aortas of mouse models. Our preliminary results have uncovered novel hitherto unexplored vascular mechanisms of action of diabetic stimuli. Our state-of-the-art transcriptomic approaches in this proposal could significantly advance the field and make a key impact by unraveling new factors and mechanisms underlying the sustained vascular complications of diabetes. The completed results could provide strategies for the development of sorely needed newer and novel therapies to reduce the morbidity and mortality of diabetic cardiovascular disease.