Epigenetic regulation of vascular smooth muscle cell phenotype

描述(申请人提供)：血管平滑肌细胞表型的表观遗传调控血管平滑肌细胞(SMC)分化是血管生成和血管生成过程中的一个非常重要的过程，人们普遍认为SMC表型的改变在动脉粥样硬化、高血压和再狭窄等几种突出的心血管疾病状态的进展中起着作用。尽管血清反应因子(SRF)和肌钙蛋白因子对SMC的分化至关重要，但我们实验室和其他实验室最近的研究表明，表观遗传机制对SMC特异性基因表达的整体模式也是至关重要的。事实上，我们已经确定组蛋白去甲基酶jmjd1a是一种与肌钙蛋白因子相互作用的蛋白，并且已经表明jmjd1a通过使SMC特异性的H3K9去甲基化来刺激SMC分化标记基因的表达。目前建议的一个主要目标将是密切检查jmjd1a基因敲除小鼠对SMC表型的影响，我们将在几个SMC表型调节的体外和体内模型中表征H3K9甲基化。H3K9甲基化与DNA甲基化密切相关，有趣的是，SMC特异性启动子内的SRF结合区嵌入在CpG岛中。根据我们的初步数据表明，SMC特异性启动子受甲基化调节，目标2的目标是确定涉及的分子机制。最后，为了更好地了解控制SMC表型的全球染色质变化，我们与Jason Lieb和Terry Furrey建立了合作，利用DNA酶超敏反应和甲醛辅助的调节元件分离(FAIRE)来“绘制”SMC中开放的染色质区域。我们已经从人的主动脉SMC培养中生成了一个全基因组图谱，并确定了一些以前未被研究的启动子区域对于SMC特异性基因的表达具有潜在的重要意义。目标3的目的是测试这些区域是否在体内驱动表达，并确定参与其中的染色质修饰和转录因子。

DESCRIPTION (provided by applicant): Epigenetic regulation of vascular smooth muscle cell phenotype Vascular smooth muscle cell (SMC) differentiation is a very important process during vasculogenesis and angiogenesis, and it is well recognized that alterations in SMC phenotype play a role in the progression of several prominent cardiovascular disease states including atherosclerosis, hypertension, and restenosis. Although serum response factor (SRF) and the myocardin factors are critical for SMC differentiation, recent studies from our lab and others indicate that epigenetic mechanisms are also critical for the overall pattern of SMC-specific gene expression. Indeed, we identified the histone demethylase, jmjd1a, as a myocardin factor interacting protein and have shown that jmjd1a stimulates SMC differentiation marker gene expression in aortic SMC cultures by demethylating H3K9 near the SMC-specific. A major goal of the current proposal will be to closely examine jmjd1a knock-out mice for effects on SMC phenotype, and we will characterize H3K9 methylation in several in vitro and in vivo models of SMC phenotypic modulation. H3K9 methylation is strongly associated with DNA methylation, and interestingly, the SRF binding regions within the SMC-specific promoters are embedded within CpG islands. Based on our preliminary data indicating that the SMC-specific promoters are regulated by methylation, the goal of Aim 2 is to identify the molecular mechanisms involved. Finally, in an attempt to better understand the global chromatin changes that control SMC phenotype, we have established collaborations with Jason Lieb and Terry Furrey to "map" open chromatin regions in SMC using DNase hypersensitivity and Formaldehyde-Assisted Isolation of Regulatory Elements (FAIRE). We have generated a genome-wide map from human aortic SMC cultures and have identified a number of previously unexamined promoter regions as potentially important for SMC-specific gene expression. The goals of Aim 3 are to test whether these regions drive expression in vivo and to identify the chromatin modifying and transcription factors that are involved.