Calcium-dependent Regulation of Smooth Muscle Phenotype

平滑肌表型的钙依赖性调节

• 批准号: 7148612
• 负责人: Brian Wamhoff
• 金额: $ 28.49万
• 依托单位: UNIVERSITY OF VIRGINIA
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-09-15 至 2011-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7148612
• 关键词: angiogenesis; atherosclerosis; biological signal transduction; blood vessels; calcineurin; calcium flux; cardiovascular injury; cell differentiation; cellular polarity; embryonic stem cell; gene expression; genetically modified animals; laboratory mouse; muscle contraction; phenotype; sphingosine; transcription factor; vascular smooth muscle

DESCRIPTION (provided by applicant): The overall aim of this proposal is to determine the mechanisms by which calcium (Ca) signaling differentially regulates vascular smooth muscle cell (SMC) phenotype. SMC phenotypic modulation is characterized by alterations in SMC differentiation marker gene expression (SMGX) including SM cr-actin, smooth muscle myosin heavy chain (SMMHC) and SM22a. Transcriptional regulation of SM a-actin, SMMHC, and SM22a is regulated in part through the transcription factor SRF (serum response factor) binding to CArG c/s regulatory promoter elements. Multiple SRF-CArG-dependent signaling pathways have been described in regulating SMC phenotypic modulation during development, in mature contractile SMCs and in vascular disease (i.e. atherosclerosis. However, although Ca has connections to virtually every biological process in nature, including SMC contraction, it is still unclear what role Ca plays in regulating SMGX and SMC phenotypic modulation. We recently showed in adult SMCs that Ca influx via L-type voltage-gated Ca channels (VGCC) resulted in an increase in SMGX through mechanisms that are dependent on RhoA/Rho-kinase, myocardin (a SMC-selective SRF co-factor) and increased binding of SRF to CArG cis promoter regulatory elements required for SMGX. Exciting recent studies from our lab provide evidence showing that the contractile agonist sphingosine-1-phosphate increases SMGX in part via VGCCs/Rho-kinase/SRF and selective S1P receptor subtypes. However, sphingosine-1-phosphate, not VGCC activation alone, also mediates SMGX through calcineurin and enrichment of NFAT2, a Ca-activated transcription factor, within CArG promoter elements of intact chromatin. Taken together, the preceding studies clearly implicate a role for differential regulation of SMGX by sphingosine-1-phosphate- and depolarization-dependent Ca signaling. Thus, Aim 1 will determine molecular mechanisms by which Ca differentially regulates SMGX in adult SMCs. Our hypothesis is that sphingosine-1-phosphate and depolarization-induced Ca influx regulate SRF-dependent SMGX through RhoA/Rho-kinase/myocardin but differentially regulate the interaction of Ca-activated transcription factors mediated by calcineurin/NFAT signaling pathways and by inducing changes in chromatin structure that enhance binding of SRF to CArG elements. Aim 2 will determine the role of Ca-dependent signaling on differentiation, maturation and function of SMCs derived from embryonic stem cells. We will employ embryonic stem cells genetically null for select genes (defined in Aim 1) to determine the role of these factors in regulating SMC differentiation/maturation/function in the embryoid body model of SMC differentiation. Aim 3 will determine the role of Ca signaling pathways in SMC phenotypic modulation associated with vascular injury using SMC-selective Cre/lox technology. The overall hypothesis is that Ca-dependent molecular mechanisms regulate SMGX during SMC development and maintenance of the contractile phenotype, and that these control mechanisms are altered during phenotypic modulation associated with atherosclerosis.

描述（由申请人提供）：该提案的总体目的是确定钙（CA）信号差异调节血管平滑肌细胞（SMC）表型的机制。 SMC表型调制的特征是SMC分化标记基因表达（SMGX）的改变，包括SM CR-ACTIN，平滑肌肌球蛋白重链（SMMHC）和SM22A。 SM A-ACTIN，SMMHC和SM22A的转录调控部分通过转录因子SRF（血清反应因子）与CARG C/S调节启动子元件结合。 Multiple SRF-CArG-dependent signaling pathways have been described in regulating SMC phenotypic modulation during development, in mature contractile SMCs and in vascular disease (i.e. atherosclerosis. However, although Ca has connections to virtually every biological process in nature, including SMC contraction, it is still unclear what role Ca plays in regulating SMGX and SMC phenotypic modulation. We recently showed in adult SMCs that Ca influx通过L型电压门控CA通道（VGCC），通过依赖RhoA/Rho-kinase，Myocardin，SMC选择性SRF Co-Factor的机制增加了SMGX，并增加了SRF对CARG CIS启动元素的结合，以使我们的SMGX受到cons smgx的影响。通过VGCC/Rho-kinase/srf的一部分增加了SMGX，但是选择性S1P受体亚型，但是，鞘氨醇1-磷酸盐，而不是单独的VGCC激活，也通过钙调蛋白和NFAT2的富含NFAT2（CA激活的转录因子）介导SMGX。综上所述，前面的研究清楚地暗示了通过鞘氨醇1-磷酸和去极化依赖性CA信号传导对SMGX差异调节的作用。因此，AIM 1将确定CA在成年SMC中差异调节SMGX的分子机制。我们的假设是，通过RhoA/Rho--激酶/肌动蛋白调节SRF依赖性SMGX，但差异地调节了CA激活转录因子的相互作用，该相互作用由钙调蛋白/NFAT信号通路和诱导SR诱导Chartin emantity Carcing emations Carcting Carcing构建的变化。 AIM 2将确定CA依赖性信号传导对胚胎干细胞的分化，成熟和功能的作用。我们将采用胚胎干细胞以遗传为null的精选基因（在AIM 1中定义）来确定这些因素在调节SMC分化/成熟/功能中的作用在SMC分化的胚胎体模型中。 AIM 3将确定使用SMC选择性CRE/LOX技术与血管损伤相关的SMC表型调节中CA信号通路的作用。总体假设是CA依赖性分子机制在SMC开发和维持收缩表型过程中调节SMGX，并且在与动脉粥样硬化相关的表型调节过程中，这些控制机制发生了改变。