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Thrombin-induced Signaling in Vascular Smooth Muscle

血管平滑肌中凝血酶诱导的信号传导

基本信息

批准号：
6866428
负责人：
GEORGE A STOUFFER
金额：
$ 25.46万
依托单位：
UNIV OF NORTH CAROLINA CHAPEL HILL
依托单位国家：
美国
项目类别：
财政年份：
2002
资助国家：
美国
起止时间：
2002-04-01 至 2007-03-31
项目状态：
已结题

项目摘要

Excessive proliferation of migration of vascular smooth muscle cells (SMC) plays a major role in the development of atherosclerotic plaques. Alpha-thrombin is of particular interest because it has been implicated in mediating vascular pathology in several different animal models. There is also compelling evidence that alpha-v-beta-3 integrins are involved in vascular healing responses; the challenge has been to understand their role in regulating SMC proliferation and migration in the injured artery. In studies from my laboratory, we found that alpha-thrombin-induced proliferation of human aortic SMC was partially inhibited by alpha-v- beta-3 antagonists and that alpha-v-beta-3 antagonists block alpha- thrombin-induced JNK1 activation. Furthermore, we have identified alphav-beta-3 integrin-dependent cytoplasmic events that occur in SMC in response to treatment with alpha-thrombin which provide insight into the integration signals from G-protein-coupled receptors and integrins. In particular, non-muscle myosin-A (NM-A), a cytoskeletal protein implicated in SMC proliferation, rapidly associates with alpha-v beta-3 integrins and with focal adhesion (FAK) following treatment of rat aortic SMC (RASMC) with alpha-thrombin. NM-A provides a unique site for regulation as an equilibrium exists between two distinct conformations: a folded state in which myosin can not assemble into filaments (i.e. 10S conformation) and an extended conformation that promotes the assembly of filaments (i.e. 6S). Equilibration between 6S and 10S is sensitive to the phosphorylation state of myosin light chain (MLC). Thus phosphorylation of MLC, which is stimulated by PAR-1-mediated signaling, could play an important regulatory role in integrin-mediate signaling in response to activation of G protein-coupled receptors. In the proposed studies, we will test the following hypothesis: The inducible association of NM-A with alpha-v beta-3 integrins, FAK and the actin cytoskeleton is required for alpha-thrombin-induced activation of c-jun NH2-terminal kinase-1 (JNK1) in SMC and is regulated by PAR-1 activation of RhoA and phosphorylation of myosin light chain. The studies we propose will provide insight into two critically important questions in vascular biology: 1) regulation of alpha-thrombin-induced SMC growth and 2) convergence of G protein-coupled receptor and integrin signaling. These studies will also contribute to the development of effective treatments for patients with vascular disease by increasing our understanding of how alpha-v beta-3 integrins regulate vascular healing.

血管平滑肌细胞（SMC）的过度增殖和迁移在动脉粥样硬化斑块的形成中起着重要作用。α-凝血酶是特别感兴趣的，因为它已经涉及在几种不同的动物模型中介导血管病理学。还有令人信服的证据表明，α-v-β-3整合素参与血管愈合反应;挑战是了解它们在调节受损动脉中SMC增殖和迁移中的作用。在我实验室的研究中，我们发现α-凝血酶诱导的人主动脉SMC增殖被α-v-β-3拮抗剂部分抑制，并且α-v-β-3拮抗剂阻断α-凝血酶诱导的JNK 1活化。此外，我们已经确定了α v-β-3整合素依赖性细胞质事件发生在SMC中的治疗与α-凝血酶，提供了深入了解整合信号从G-蛋白偶联受体和整合素。特别是，非肌肉肌球蛋白-A（NM-A），一种与SMC增殖有关的细胞骨架蛋白，在用α-凝血酶处理大鼠主动脉SMC（RASMC）后迅速与α-v β-3整联蛋白和粘着斑（FAK）结合。NM-A提供了一个独特的调节位点，因为两种不同的构象之间存在平衡：折叠状态，其中肌球蛋白不能组装成细丝（即10 S构象）和延伸构象，促进细丝的组装（即6S）。6S和10 S之间的平衡对肌球蛋白轻链（MLC）的磷酸化状态敏感。因此，MLC的磷酸化，这是刺激PAR-1介导的信号，可以发挥重要的调节作用，在整合素介导的信号响应激活G蛋白偶联受体。在本研究中，我们将验证以下假设：NM-A与α-v β-3整合素、FAK和肌动蛋白细胞骨架的诱导性结合是α-凝血酶诱导SMC中c-jun NH 2-末端激酶-1（JNK 1）活化所必需的，并受PAR-1活化RhoA和肌球蛋白轻链磷酸化的调节。我们提出的研究将提供深入了解血管生物学中的两个至关重要的问题：1）α-凝血酶诱导的SMC生长的调节和2）G蛋白偶联受体和整合素信号转导的收敛。这些研究也将有助于开发有效的治疗血管疾病的患者，增加我们的理解如何α-v β-3整合素调节血管愈合。