Vascular Cell Phenotype on Physiologically-relevant Bioengineered Substrata

描述（由申请人提供）：虽然血管介入治疗血管闭塞性疾病已经有了很大的进步，但介入后的再狭窄（血管闭塞）仍然是一个主要的临床问题。本研究的长期目标是阐明控制血管闭塞性疾病相关VSMC行为变化的关键因素，并设计出能够探测和控制这种行为的新型工程生物材料。虽然已经有大量的研究检查了ECM变化的生化效应，但相对而言，很少有人关注ECM的生物力学特性对VSMC表型的影响。我们的初步数据表明：(i)血小板衍生生长因子（PDGF）诱导的VSMC信号传导和（ii） VSMC定向迁移都受到基质刚度的显著调节。我们进一步发现，底物硬度影响ECM沉积（I型和III型胶原）以及已知降解基质的基质金属蛋白酶(MMP) -2和-9的产生和分泌。基于这些观察结果，我们的中心假设是局部机械环境在血管稳态和对ECM结构组成的广泛调节作用中起重要作用。我们进一步假设，初始损伤促进VSMC表型开关，随后通过正反馈促进血管闭塞性疾病的发展。为了验证这些假设，我们将使用多尺度方法来探索生物力学环境在分子水平上对细胞、组织和组织工程仿生模型系统的影响。我们将使用VSMCs和来自正常和动脉粥样硬化动物（Watanabe遗传性高脂血症兔）的天然血管来获得临床相关性。具体目标1：研究机械特性（如顺应性和ECM）的相互关系，并开发生理相关的生物工程模型基质。具体目标2：确定机械环境对模拟血管生理和病理条件的生物工程基质VSMC表型调节的影响。具体目标3：通过在活体条件下的组织培养，表征机械环境和生化变化对血管行为的影响。在组织培养中验证我们的生物工程基质结果将产生有价值的数据，为阐明生物力学在ECM重塑和VSMC表型中的作用建立机制基础。这些目标的成功完成将导致通过靶向调节血管壁的ECM生物力学特性来控制与血管闭塞性疾病相关的VSMC表型的新策略。公共卫生相关性：本研究旨在了解血管中一种主要细胞类型的转换行为的控制机制，这种细胞类型在动脉粥样硬化的进展中起关键作用，动脉粥样硬化是西方世界的主要死亡原因。通过研究这些特定的机制，我们有可能发现治疗心血管疾病的新治疗策略。

DESCRIPTION (provided by applicant): While there have been vast improvements in vascular intervention to combat vascular occlusive diseases, restenosis (occlusion of the vessel) following the intervention remains a major clinical problem. The long-term goal of this proposal is to elucidate key factors that control changes in VSMC behavior associated with vascular occlusive disease and to design novel engineered biomaterials that can probe and control this behavior. While there have been extensive studies examining the biochemical effects of changes in the ECM, comparatively little attention has been focused on the effects of the biomechanical properties of the ECM on VSMC phenotype. Our preliminary data show that both (i) VSMC signaling induced by platelet-derived growth factor (PDGF) and (ii) VSMC directional migration are modulated significantly by substrate stiffness. We further find that substrate stiffness influences ECM deposition (collagen type I and III) and the production and secretion of matrix metalloproteinases (MMP) -2 and -9 that are known to degrade the matrix. Based on these observations, our central hypothesis is that the local mechanical environment has an essential role in vascular homeostasis and broad modulatory effects on the structural composition of ECM. We further hypothesize that initial injury promotes a VSMC phenotypic switch that subsequently contributes via positive feedback to the development of vascular occlusive diseases. To test these hypotheses, we will use a multi-scale approach to explore the effect of biomechanical environment on the molecular level, on cells, tissues, and tissue-engineered biomimetic model systems. We will use VSMCs and also native vessels from normal and atherosclerotic animals (Watanabe Hereditable Hyperlipidemic rabbit) to achieve clinical relevance. Specific Aim 1: Investigate the interrelationship of mechanical properties such as compliance and ECM and develop physiologically-relevant bioengineered model substrata. Specific Aim 2: Determine the effects of mechanical environment on VSMC phenotypic modulation on bioengineered substrata mimicking physiological and pathological conditions of blood vessels. Specific Aim 3: Characterize the effects of mechanical environment and biochemical changes on vessel behavior by tissue culture under in vivo-like conditions. Validation of our bioengineered substrata results in tissue cultures will yield valuable data, establishing a mechanistic foundation for elucidating the role of biomechanics on ECM remodeling and VSMC phenotype. The successful completion of these aims will lead to new strategies to control VSMC phenotype related to vascular occlusive disease by targeting regulation of ECM biomechanical properties of the vessel wall. PUBLIC HEALTH RELEVANCE: This proposal seeks to understand the mechanisms that control the switching behavior of a major cell type in blood vessels that play a key role in the progression of atherosclerosis the leading cause of death in the Western world. Through researching these specific mechanisms, we have the potential to uncover novel therapeutic strategies to treat cardiovascular disease.