Genetic and epigenetic regulation of vascular smooth muscle cell phenotype and contractility

总结 血管平滑肌细胞（SMC）的分化是血管发生和分化的重要过程， 血管生成，并且众所周知SMC表型的改变在血管生成的进展中起作用。 几种主要的心血管疾病状态，包括动脉粥样硬化、高血压和再狭窄。 在之前的资助期间，我们使用高通量测序和计算生物学来研究 全基因组水平上的人类主动脉平滑肌细胞的染色质结构和转录因子结合。我们的工作 导致了以前未被识别的SMC选择性蛋白的鉴定， 调节SMC收缩性和血压的遗传机制，以及新的转录 调节SMC特异性基因表达的机制。利用质谱分析方法，我们最近发现 SMC-选择性甲基转移酶，PRDM 6，作为心肌素因子相互作用蛋白，具有细胞培养物 以及体内数据表明PRDM 6是维持SMC分化和血压所必需的。 重要的是，最近的人类遗传学研究描述了导致导管未闭的PRDM 6编码突变 GWAS已经确定了PRDM中与血压调节和颅内动脉硬化相关的位点， 动脉瘤在目标1中，我们将确定转录机制和人类遗传变异， PRDM 6是SMC特异性表达的PRDM 6。由于PRDM 6调节基因的机制 表达是完全未知的，在Aim 2中，我们将使用全基因组方法来识别直接PRDM 6 我们将测试PRDM 6是否通过直接甲基化调节MRTF-A活性。在目标3中， 继续评估PRDM 6对血压和SMC表型调节的贡献， 体内使用我们的条件SMC特异性PRDM 6敲除小鼠。我们还与 北卡罗来纳州大学的临床心血管研究小组开始研究 PRDM 6基因型与当地人群高血压的关系。

Summary 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. During the previous funding period we used high throughput sequencing and computational biology to study chromatin structure and transcription factor binding in human aortic SMCs on a genome-wide level. Our work has led to the identification of previously unrecognized SMC-selective proteins, to the characterization of genetic mechanisms that regulate SMC contractility and blood pressure, and to novel transcription mechanisms that regulate SMC-specific gene expression. Using mass spec approaches we recently identified the SMC-selective methyltransferase, PRDM6, as a myocardin factor interacting protein and have cell culture and in vivo data that PRDM6 is required for the maintenance of SMC differentiation and blood pressure. Importantly recent human genetic study described PRDM6 coding mutations that cause patent ductus arteriosis, and GWAS have identified a locus in PRDM that was associated with BP regulation and intracranial aneurysm. In Aim 1 we will identify the transcription mechanisms and human genetic variations that regulate PRDM6 the SMC-specific expression of PRDM6. Since the mechanisms by which PRDM6 regulates gene expression are completely unknown, in Aim2 we will use genome-wide approaches to identify direct PRDM6 targets, and we will test whether PRDM6 regulates MRTF-A activity by direct methylation. In Aim 3 we will continue to evaluate the contributions of PRDM6 to the regulation of blood pressure and SMC phenotype in vivo using our conditional SMC-specific PRDM6 knockout mice. We have also established collaborations with clinical cardiovascular research teams at the University of North Carolina to begin to examine the correlation between PRDM6 genotype and hypertension in local populations.