VASCULAR SMOOTH MUSCLE REMODELING--ARGININE VASOPRESSIN

血管平滑肌重塑--精氨酸加压素

• 批准号: 7098764
• 负责人: RAPHAEL A. NEMENOFF
• 金额: $ 37.54万
• 依托单位: UNIVERSITY OF COLORADO DENVER
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/7098764
• 关键词: JUN kinase; RNA interference; arginine; arginine vasopressin; biological signal transduction; cardiac myocytes; cardiogenesis; cell differentiation; genetic regulation; genetic transcription; growth factor; guanine nucleotide binding protein; immunofluorescence technique; laboratory mouse; laboratory rat; mechanical stress; mitogen activated protein kinase; phenotype; platelet derived growth factor; protein localization; two dimensional gel electrophoresis; vascular smooth muscle

During normal development, vascular smooth muscle cells (VSMC) undergo differentiation from a proliferative phenotype characteristic of neonatal and embryonic vessels, to a contractile phenotype associated with adult vessels. In contrast to development of cardiac or skeletal muscle, VSMC retain much greater plasticity. In adult VSMC, phenotypic modulation resulting in changes in altered expression of a number of muscle-specific genes (SM-markers), results in cells with altered contractile, proliferative and migratory capacity. Transcriptional control of these genes occurs in response to multiple extracellular stimuli including circulating factors, extracellular matrix and mechanical forces. We hypothesize that phenotypic modulation requires sensing by VSMC of these multiple inputs, which integrate at the level of common signal transduction pathways. These pathways act on transcription factors, most critically serum response factor (SRF), that bind to the promoter elements of multple target genes. The goal of this proposal is to define these molecular signaling events and determine how they regulate transcription. During the previous funding period we have demonstrated that coordinated induction of SM-markers by arginine vasopression (AVP) is mediated through activation of the JNK and p38 family of MAP kinases. Induction by mechanical forces also involves these pathways. Conversely, PDGF suppression of SM-gene expression is mediated through activation of Ras and the PI3 kinase/Akt pathways. We have also demonstrated that growth of VSMC on matrices of different composition, through engagement of specific integrins and modulation of cytoskeleton, results in changes in expression of SM-markers. SRF is critical for regulation in all of these settings, and shows altered phosphorylation and subcellular localization. In this application we will focus on understanding the integration of signals generated by vasoconstrictors such as AVP, growth factors, and cell attachment resulting in alterations in gene expression. Three specific aims are proposed. Specific aim 1 will examine the role of MAP kinase and Rho family members in mediating the inductive effects of AVP. The second specific aim will define the mechanisms whereby Ras and Akt cooperate to mediate regulation of SM-gene expression by PDGF and redistribution of SRF. The final specific aim will examine the role of SRF phosphorylation in mediating control of SM-gene expression. These studies should provide a detailed molecular understanding of the events that control phenotypic remodeling in VSMC, and provide potential new targets for controlling this process in disease states.

在正常发育过程中，血管平滑肌细胞 (VSMC) 会从 新生儿和胚胎血管的增殖表型特征转变为与成人血管相关的收缩表型。与心肌或骨骼肌的发育相比，VSMC 保留了更大的可塑性。在成人 VSMC 中，表型调节导致许多肌肉特异性基因（SM 标记）表达发生变化，从而导致细胞收缩、增殖和迁移能力发生改变。这些基因的转录控制是响应多种细胞外刺激而发生的，包括循环因子、细胞外基质和机械力。我们假设表型调节需要 VSMC 感知这些多个输入，这些输入在常见信号转导途径的水平上进行整合。这些途径作用于转录因子，最关键的是血清 反应因子（SRF），与多个靶基因的启动子元件结合。该提案的目标是定义这些分子信号传导事件并确定它们如何调节转录。在之前的资助期间，我们已经证明精氨酸血管加压 (AVP) 对 SM 标记物的协调诱导是通过激活 JNK 和 MAP 激酶的 p38 家族来介导的。机械力感应也涉及这些途径。相反，PDGF 对 SM 基因表达的抑制是通过激活 Ras 和 PI3 激酶/Akt 途径介导的。我们还证明了增长 VSMC 在不同组成的基质上，通过特定整合素的参与和细胞骨架的调节，导致 SM 标记物表达的变化。 SRF 对于所有这些环境中的调节都至关重要，并且显示出磷酸化和亚细胞定位的改变。在此应用中，我们将重点了解血管收缩剂（如 AVP、生长因子和细胞附着）产生的信号整合，从而导致基因表达的改变。提出了三个具体目标。具体目标1将 检查 MAP 激酶和 Rho 家族成员在介导 AVP 诱导作用中的作用。第二个具体目标将确定 Ras 和 Akt 合作介导 PDGF 对 SM 基因表达的调节和 SRF 重新分配的机制。最终的具体目标将检查 SRF 磷酸化在介导 SM 基因表达控制中的作用。这些研究应该提供对 VSMC 中控制表型重塑事件的详细分子理解，并为在疾病状态下控制这一过程提供潜在的新靶点。