MYOCARDIN AND VASCULAR SMOOTH MUSCLE

心肌素和血管平滑肌

• 批准号: 6929664
• 负责人: Michael S Parmacek
• 金额: $ 24.17万
• 依托单位: UNIVERSITY OF PENNSYLVANIA
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-07-06 至 2009-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6929664
• 关键词: angiogenesis; animal genetic material tag; cell differentiation; cell growth regulation; cell migration; cell morphology; developmental genetics; embryo /fetus; embryogenesis; embryonic stem cell; gene expression; genetic regulation; genetic regulatory element; genetically modified animals; immunocytochemistry; intermolecular interaction; laboratory mouse; protein structure function; transcription factor; vascular smooth muscle

The differential patterning of smooth muscle cells (SMCs) and pericytes within specific blood vessels ultimately defines and distinguishes the functional properties of the arteries, veins and capillaries. SMC phenotype and patterning, in turn, are determined via transcriptional programs that respond to developmental and environmental signals and cues. We have used transgenic and gene targeting strategies to elucidate the transcriptional programs that regulate vascular SMC differentiation. Our group and others have reported recently that the SAP domain transcription factor, myocardin, plays a critical role in SMC differentiation. Preliminary studies presented herein demonstrate that: i) myocardin is expressed in a precise developmentally regulated pattern in vascular and visceral SMCs, ii) forced expression of myocardin in non-SMCs activates multiple SMC-specific transcriptional regulatory elements, iii) forced expression of myocardin activates SMC-restricted genes in undifferentiated embryonic stem (ES) cells, and iv) expression of adominant-negative myocardin mutant protein or myocardin siRNA in SMCs represses activity of the SMC-specific SM22alpha-promoter. Together these studies suggest the central hypothesis that will be examined in the proposed studies: myocardin plays a critical role in the SRF-dependent transcriptional program that regulates SMC differentiation and phenotype. The overall goat of this project is to elucidate the molecular basis of myocardin-induced SMC differentiation. The specific aims are to: 1) Examine the cell autonomous functions of myocardin in SMCs during embryonic development, and on maintenance of the SMC phenotype, 2) Examine the molecular mechanisms underlying the activity and specificity of the myocardin-SRF dependent transcriptional program that regulates SMC differentiation, and 3) Generate and characterize mice containing null and conditioned mutations in the myocardin gene. At a basic level these studies will provide new insights into the transcriptional programs regulating SMC differentiation and modulation of SMC phenotype. As such, these studies are relevant to understanding the pathogenesis of atherosclerosis and other vascular proliferative syndromes.

特定血管内平滑肌细胞（SMC）和周细胞的差异模式最终定义和区分动脉、静脉和毛细血管的功能特性。SMC的表型和模式，反过来，是通过转录程序，响应发展和环境的信号和线索。我们已经使用转基因和基因靶向策略来阐明调节血管SMC分化的转录程序。我们的小组和其他人最近报道，SAP结构域转录因子，myocardin，在SMC分化中起着至关重要的作用。本文提出的初步研究表明：i）心肌蛋白在血管和内脏SMC中以精确的发育调节模式表达，ii）心肌蛋白的强制表达， 在非SMC中，肌钙蛋白的强制表达激活多个SMC特异性转录调节元件，iii）肌钙蛋白的强制表达激活未分化胚胎干（ES）细胞中的SMC限制性基因，和iv）在SMC中，adominant-negative肌钙蛋白突变蛋白或肌钙蛋白siRNA的表达抑制SMC特异性SM 22 α启动子的活性。总之，这些研究表明，将在拟议的研究中检查的中心假设：myocardin起着至关重要的作用，在SRF依赖的转录程序，调节SMC的分化和表型。本课题的总体目标是阐明心肌素诱导平滑肌细胞分化的分子基础。具体目标是：1）检查在胚胎发育期间SMC中心肌素的细胞自主功能，以及SMC表型的维持，2）检查调节SMC分化的心肌素-SRF依赖性转录程序的活性和特异性的分子机制，以及3）产生和表征在心肌素基因中含有无效和条件突变的小鼠。在基础水平上，这些研究将为调控SMC分化和SMC表型调节的转录程序提供新的见解。因此，这些研究与了解动脉粥样硬化和其他血管增生综合征的发病机制有关。