Regulation of vascular smooth muscle cell plasticity

项目摘要/摘要 VSMC表型的调节仍然是血管平滑肌细胞中一个关键的未回答的问题。 肌细胞（VSMC）生物学。VSMC具有去分化和再进入的可塑性 细胞周期允许生长和愈合。然而，这种可塑性也有助于 严重的血管病变，包括再狭窄、移植失败、动脉粥样硬化和移植 血管病变值得注意的是，尽管进行了大量的研究，但调节VSMC可塑性的过程仍然是不稳定的。 很大程度上是未知的，很少有治疗成功地针对这一过程。与不断增长的 许多患有血管疾病的患者迫切需要发现新的靶点。 有正当理由 我们取得了令人兴奋的发现，去分化的VSMC表达基因 与干细胞多能性相关的基因，包括Sox 2、Oct 4、Nanog和KLF 4。我们提出 这些干细胞相关基因解释了成熟VSMC独特的可塑性。 最近的突破性研究已经确定了泰特（10 - 11易位）家族， 染色质修饰蛋白作为胚胎和造血多能性的关键介质 干细胞我们的初步结果暗示TET 2作为VSMC的表观遗传主调节因子 表型。重要的是，我们发现TET 2抑制干细胞相关基因的表达， 和去分化表型的经典标志物。我们先前发现， mTORC 1抑制剂雷帕霉素促进VSMC分化。我们现在发现雷帕霉素 调节TET 2表达。值得注意的是，我们发现TET 2也调节miRNA， 调节分化特异性和干细胞相关基因表达。我们 假设TET 2通过其协调作用成为VSMC表型的主要调节因子 调节收缩和干细胞相关基因的启动子以及miRNA。 在具体目标1中，我们将确定干细胞相关基因在VSMC表型中的作用。 在具体目标2中，我们将确定TET 2调节的miRNA在VSMC表型中的作用。在 具体目标3，我们将确定是否靶向TET 2或干细胞相关基因， 在内膜增生的体内模型中的治疗效用。如果我们的目标实现，我们将 已经确定了一种新的机制VSMC可塑性。了解关键 mTORC 1调节VSMC表型的机制将导致改善的 心血管治疗学

Project Summary/Abstract Regulation of VSMC phenotype remains a key unanswered question in vascular smooth muscle cell (VSMC) biology. VSMC retain a remarkable plasticity to de-differentiate and re-enter the cell cycle allowing for growth and healing. However, such plasticity can also contribute to severe vascular pathologies, including restenosis, graft failure, atherosclerosis, and transplant vasculopathy. Remarkably, despite intense study, the process regulating VSMC plasticity is largely unknown with few therapies successfully targeting this process. With the growing numbers of patients suffering from vascular disease the discovery of novel targets is urgently warranted. We have made the exciting discovery that de-differentiated VSMC express genes associated with stem cell pluripotency, including Sox2, Oct4, Nanog, and KLF4. We propose that these stem cell-associated genes account for the unique plasticity of mature VSMC. Recent groundbreaking studies have identified the TET (ten-eleven translocation) family of chromatin modifying proteins as key mediators of pluripotency in embryonic and hematopoietic stem cells. Our Preliminary Results implicate TET2 as an epigenetic master regulator of VSMC phenotype. Importantly, we find that TET2 inhibits expression of stem cell-associated genes and classic markers of the de-differentiated phenotype. We previously discovered that the mTORC1 inhibitor, rapamycin, promotes VSMC differentiation. We now find that rapamycin regulates TET2 expression. Remarkably, we find that TET2 also regulates miRNAs that can modulate both differentiation-specific and stem cell-associated gene expression. We hypothesize that TET2 is a master regulator of VSMC phenotype through its coordinated regulation of the promoters of contractile and stem cell-associated genes, as well as of miRNAs. In Specific Aim 1, we will determine the role of stem cell-associated genes in VSMC phenotype. In Specific Aim 2, we will determine the role of TET2-regulated miRNAs in VSMC phenotype. In Specific Aim 3, we will determine whether targeting TET2 or stem cell-associated genes has therapeutic utility in in vivo models of intimal hyperplasia. If our goals are achieved, we will have identified a novel mechanism underlying VSMC plasticity. Understanding the critical mechanisms by which mTORC1 regulates VSMC phenotype will lead to improved cardiovascular therapeutics.