Bioengineered Substrata to Probe Cellular Behavior

描述(由申请人提供)： 动脉内膜增生和血管收缩导致的再狭窄仍然是动脉闭塞性疾病治疗中的一个主要问题。平滑肌细胞在血管重塑中起着重要作用，对其细胞表型进行局部控制将极大地减少再狭窄的发生。血管损伤的一个常见结果是细胞外基质过度重塑，其中含有丰富的胶原蛋白和蛋白多糖。虽然这会导致生化特性的变化，但它也会显著改变生物力学特性。基于最近细胞对具有不同机械特性的基质的响应，我们的中心假设是基质的生物力学特性将调节与再狭窄相关的血管平滑肌细胞的表型。目前治疗再狭窄的方法主要涉及可溶性因子，但很少有人关注基质生物力学特性对细胞表型的影响。这项拟议的研究的目的是建立模型系统，以概括血管重塑过程中的生物力学环境，并确定与再狭窄相关的基质顺应性和细胞表型之间的关键关系。这一目标将通过研究基质顺应性对模型生物工程基质上平滑肌细胞表型的影响来实现，该模型生物工程基质旨在展示从微观到宏观长度尺度的顺应性的系统变化。这项研究的结果将是一种新的体外模型系统，它将更接近于重建的基质的生物力学环境，在其中人们可以测试药物对血管平滑肌细胞表型的影响。该模型系统也可应用于其他病理生理系统。为了控制局部的机械柔度，将使用合成水凝胶作为模型底物。目标1是开发在宏观和微观尺度上具有明确机械顺应性的生物工程基质。目标2和目标3的研究结果将用于目标1的改进。目标2将建立和量化基质顺应性和与再狭窄相关的血管平滑肌细胞表型之间的关系。目的3将测试底物顺应性对可能的机械敏感细胞成分(整合素、细胞骨架、FAK、帕西林、Rho GTP酶)表达、定位和活性的影响。这些研究将推动对控制血管平滑肌细胞表型改变的物理因素的新见解，目的是开发阻止再狭窄的治疗方法。

DESCRIPTION (provided by applicant): Restenosis due to intimal hyperplasia and vasoconstriction remains a major problem in treatments of arterial occlusive disease. Smooth muscle cells play a major role in vascular remodeling, and local control of their cellular phenotype would greatly enhance efforts to reduce the occurrence of restenosis. A common result of vascular injury is excessive remodeling of the extracellular matrix, which becomes rich in collagens and proteoglycans. While this leads to changes in biochemical properties, it also significantly alters biomechanical properties. Based on recent work that cells respond to substrata with varying mechanical properties, our central hypothesis is that the biomechanical properties of the substratum will modulate vascular smooth muscle cell cellular phenotype that is relevant for restenosis. Current therapies for restenosis largely involve soluble factors, but little attention has been focused on understanding the effects of substratum biomechanical properties on cellular phenotype. The objective of the proposed research is to create model systems that will recapitulate the biomechanical environment during vascular remodeling and to identify key relationships between substrate compliance and cellular phenotype associated with restenosis. This objective will be achieved by investigating the effect of substrate compliance on the cellular phenotype of smooth muscle cells on model bioengineered substrata that are designed to exhibit a systematic variation in their compliance ranging from the microscopic to macroscopic length scales. The outcome of this research will be a novel in vitro model system that will more closely mimic the biomechanical environment of the remodeled matrix in which one can test the effects of agents on vascular smooth muscle cell phenotype. This model system can also be applied to other pathophysiologic systems. Synthetic hydrogels will be used as model substrata in order to control the local mechanical compliance. Aim 1 is to develop bioengineered substrata with well-defined mechanical compliance at the macro- and microscales. Results from studies in Aims 2 and 3 will be used in the refinement of Aim 1. Aim 2 will establish and quantify relationships between substrate compliance and vascular smooth muscle cell phenotypes associated with restenosis. Aim 3 will test the effects of substrate compliance on the expression, localization, and activity of putative mechanosensing cellular components (integrins, cytoskeleton, FAK, paxillin, Rho GTPases). These studies will advance new insights on the physical factors that control phenotypic modulation of vascular smooth muscle cells with the aim of developing therapies to block restenosis.