Stiffness, cadherins, and integrins in mechanochemical signaling

描述(申请人提供)：本项目重点研究钙粘附素、整合素和细胞骨架协同调节血管平滑肌细胞(VSMCs)增殖的机制。VSMCs的异常去分化和增殖在损伤和动脉粥样硬化部位的血管狭窄中起主要作用。研究人员已经表明，这些部位局部组织硬度的异常增加改变了整合素介导的细胞-ECM和钙粘附素介导的细胞-细胞黏附，这两种细胞黏附似乎对增殖至关重要。 后遗症。了解动脉力学的这些变化如何调控增殖，不仅是制定合理的阻断血管疾病进展的策略的优先事项，而且也为更广泛地了解机械力、钙粘附素和整合素如何合作影响生物功能提供了机会。我们认为，在肌动蛋白细胞骨架中产生的Rho介导的张力将来自钙粘附素和整合素的信号耦合到一个整合的机械力化学信号系统中，该信号系统调节增殖。在这项提案中，Chen和Assoian实验室利用他们在工程微环境和细胞周期黏附调节方面的各自专业知识，通过结合体外、体内和体内模型系统的综合方法，研究组织硬化如何启动增殖刺激信号。我们发现血管损伤部位的组织硬化会导致 N-钙粘附素的表达显著增加，这是血管平滑肌细胞增殖和血管狭窄所必需的。具体目的1研究细胞外基质僵硬对N-钙粘附素的刺激作用以及N-钙粘附素对VSMC周期的刺激作用的机制。具体目标2将研究RhoA和细胞骨架张力在僵硬和钙粘附素诱导的循环中的作用。为了开始探索这一新的体内增殖途径的相关性，特殊目的3将研究ECM硬化、FAK和N-钙粘素在体内VSMC周期中的相互作用。该项目将导致对血管平滑肌细胞如何协调钙粘附素、整合素和细胞骨架张力的信号进入增殖反应的完整分子理解，为在体内和体外研究这些复杂的粘连和机械效应提供新的方法，并可能提出新的治疗策略来阻断再狭窄和动脉硬化的进展。

DESCRIPTION (provided by applicant): This project focuses on the mechanisms by which cadherins, integrins and the cytoskeleton cooperate to regulate proliferation in vascular smooth muscle cells (VSMCs). Aberrant dedifferentiation and proliferation of VSMCs plays a major role in vascular stenosis at sites of injury and atherosclerosis. The investigators have shown an aberrant increase in local tissue stiffness at these sites that changes integrin-mediated cell-ECM and cadherin-mediated cell-cell adhesion, both of which appear to be critical for the proliferative sequelae. Understanding how these changes in arterial mechanics regulate proliferation is not only a priority in the development of rational strategies to interrupt progression of vascular disease, but also provides an opportunity to more broadly understand how mechanical forces, cadherins, and integrins cooperate to influence biological functions. We propose that Rho-mediated tension generated in the actin cytoskeleton couples signals from cadherins and integrins in an integrated mechanochemical signaling system that regulates proliferation. In this proposal, the Chen and Assoian labs bring to bear their respective expertise in engineered microenvironments and adhesive regulation of the cell cycle to investigate how tissue stiffening initiates a stimulatory signal for proliferation in an integrated approach that combines in vitro, x vivo, and in vivo model systems. We show that tissue stiffening at sites of vascular injury results in a dramatic increase in N-cadherin expression and that this effect is required for VSMC proliferation and vascular stenosis. Specific Aim 1 will characterize the mechanisms underlying the stimulatory effect of ECM stiffness on N-cadherin and the stimulatory effect of N-cadherin on VSMC cycling. Specific Aim 2 will examine the role of RhoA and cytoskeletal tension in stiffness- and cadherin-induced cycling. To begin to explore the relevance of this novel proliferative pathway in vivo, Specific Aim 3 will examine the interplay between ECM stiffening, FAK and N-cadherin during VSMC cycling in vivo. This project will lead to an integrated molecular understanding of how vascular smooth muscle cells coordinate signals from cadherins, integrins, and cytoskeletal tension into a proliferative response, provide novel approaches to study these complex adhesive and mechanical effects both in vivo and in vitro, and may suggest new therapeutic strategies to interrupt the progression of restenosis and arteriosclerosis.