Biomimetic Vascular Matrix for Vascular Smooth Muscle Cell Mechanobiology and Pathology

总结

SUMMARY Arterial stiffness is a key risk factor for cardiovascular disease (CVD) events. Change in arterial stiffness is a significant pathology in vascular injury, atherosclerosis, and coronary disease by which stiffening of the vessel wall promotes anomalous migration and proliferation of vascular smooth muscle cells (VSMCs) causing neointima formation of the vessel wall. Yet, the molecular mechanisms by which pathological ECM stiffness regulates VSMC proliferation and migration associated with pathological ne- ointima formation are unclear. This research proposal will address this gap by exploring how changes in arterial stiffness elicit VSMC behaviors that contribute to CVD. More specifically, this work draws upon newly collected preliminary data that show a novel role for the protein survivin as a key regulator of stiffness-mediated VSMC proliferation and migration and an effector of arterial stiffening and remodel- ing. Using mouse and human VSMCs, this study will first explore how vascular ECM stiffness impacts VSMC migration, proliferation, and chromatin organization at the single-cell level (early stage of disease progression; Aim 1); and, secondly, determine how pathological ECM stiffness drives neointima for- mation altering the local mechanical environment of VSMCs in vitro (advanced stage of disease pro- gression; Aim 2). Lastly, this research proposal will test survivin’s role in regulating both ECM production and arterial stiffness (in vivo animal model; Aim 2). These aims will be achieved using a 3D cell culture using a novel in vitro porcine decellularized aorta ECM based (daECM) fibrous scaffold system and engineered mouse injury models. Briefly, VSMCs isolated from mouse and human aortas will be cultured on daECM-based nanofibrous scaffolds of different stiffnesses that mimic normal and pathological con- ditions in the body. The VSMC responses to pathological ECM stiffness will be analyzed using advanced microscopy to observe changes in cellular/nuclear structure, biomechanical properties, and the RNA and protein expressions at the single-cell level in vitro. Finally, engineered mice will be used to study stiffness and VSMC function in intact arteries, performing a histological examination and biochemical analyses of dissected tissue after stiffness is manipulated by arterial injury, drug treatment, or genetic mutations. This project will, for the first time, study the molecular and biophysical mechanisms by which survivin 1) mediates stiffness-sensitive VSMC functions, and 2) contributes to neointima formation and stiffening, revealing a completely new aspect of survivin biology in VSMCs and in the pathology of arte- rial stiffness. Overall, this proposal is unique in its ability to identify potential new therapeutic targets for the treatment of CVDs.