Role of VSMC-Derived Exosomes in the Cardiovascular Complications of Diabetes

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 DESCRIPTION (provided by applicant): The cardiovascular complications of diabetes derive, in part, from pro-atherosclerotic changes in the function of endothelial cells (ECs), macrophages, and vascular smooth muscle cells (VSMCs). Thus, changes in miRNA expression in VSMCs as a result of diabetes may promote the cardiovascular complications of diabetes via exosome mediated transfer of miRNA that induce endothelial activation and arterial inflammation. The objective of this proposal is determining the impact of exosome mediated transfer of miR-221/222 in the diabetes mediated increase in cardiovascular disease. Our preliminary data demonstrate that diabetic VSMC-derived exosomes (DVEs) promote endothelial cell activation, endothelial dysfunction, and a shift of macrophages toward an inflammatory phenotype. Furthermore, we found that DVEs promote atherosclerotic plaque formation in vivo. This proposal hypothesizes: Diabetes is accompanied by increased miR-221/222 in the exosomes secreted by VSMCs that accelerates cardiovascular disease progression by promoting endothelial cell activation and dysfunction as well as a polarization of macrophages toward a pro-inflammatory phenotype (M1). The hypothesis will be tested through three specific aims: 1) Demonstrate that DVEs promote atherosclerotic plaque formation through an increase in miR-221/222.; 2) Demonstrate that DVEs promote endothelial cell activation and increased reactive oxygen species through eNOS uncoupling as well as a shift in macrophage phenotype toward the pro-inflammatory M1 state; 3) Link loss of the IGFR in VSMCs to the increased miR-221/222 content of DVEs and increased atherosclerotic plaque formation in response to DVE treatment. Aim 1 will demonstrate that DVEs promote atherosclerotic plaque formation. Aims 2 will characterize how DVEs promote EC dysfunction, EC activation, and polarization of macrophages toward an inflammatory phenotype. Each aim will also examine the role of miR-221/222 in these effects. Aim 3 will extend the findings of our current research to understand the mechanism underlying the increase in miR-221/222 in DVEs. Together the expected outcome of this project is a demonstration that diabetes is accompanied by the generation of DVEs that promote cardiovascular disease in ECs and macrophages. These data will have a significant positive impact as they will identify novel mechanisms behind the increased cardiovascular disease in the diabetic population. The research in this proposal is innovative because it will drive a paradigm shift in our understanding of the role of VSMCs in atherosclerotic lesion formation by introducing a novel mechanism whereby VSMCs alter EC and macrophage function.