Vascular Cell Phenotype on Physiologically-relevant Bioengineered Substrata

描述（由申请人提供）：虽然在血管介入治疗血管闭塞性疾病方面已经取得了巨大的进步，但介入治疗后的再狭窄（血管闭塞）仍然是一个主要的临床问题。该提案的长期目标是阐明控制与血管闭塞性疾病相关的VSMC行为变化的关键因素，并设计可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ECM中的变化的生物化学效应，但相对较少的注意力集中在ECM的生物力学性质对VSMC表型的影响上。我们的初步数据表明，（i）由血小板衍生生长因子（PDGF）诱导的VSMC信号传导和（ii）VSMC定向迁移都受到基底刚度的显著调节。我们进一步发现，基板刚度影响ECM沉积（胶原蛋白I型和III型）和生产和分泌的基质金属蛋白酶（MMP）-2和-9已知降解基质。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内稳态和广泛的ECM结构组成的调节作用中起着至关重要的作用。我们进一步假设初始损伤促进VSMC表型转换，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。我们将使用正常和动脉粥样硬化动物（Watanabe Hereditable Hypertrophemic Rabbit）的VSMC和天然血管来实现临床相关性。具体目标1：研究柔顺性和ECM等机械性能的相互关系，开发生理相关的生物工程模型基质。具体目标二：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上的VSMC表型调节的影响。具体目标3：通过在类似体内的条件下进行组织培养，表征机械环境和生化变化对血管行为的影响。我们的生物工程基质的组织培养结果的验证将产生有价值的数据，建立一个机制的基础，阐明ECM重塑和VSMC表型的生物力学的作用。这些目标的成功完成将导致新的策略，以控制血管闭塞性疾病相关的VSMC表型，通过靶向调节ECM的血管壁的生物力学特性。公共卫生相关性：该提案旨在了解控制血管中主要细胞类型转换行为的机制，这些细胞类型在动脉粥样硬化的进展中发挥关键作用，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，我们有可能发现新的治疗策略来治疗心血管疾病。

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.