RAF KINASE AND EPIGENETIC REGULATION OF FETAL VASCULAR DEVELOPMENT

 描述(由申请者提供)：RAF激酶与胎儿血管发育的表观遗传学调节。项目摘要血管系统的发育是一个动态的过程，依赖于众多基因的协调表达。然而，在血管发育过程中调节基因表达的因素并没有得到很好的定义。我们的初步数据和其他人关于B-Raf基因敲除小鼠血管发育受损的报告已经阐明了这一途径在血管发育中的意义。重要的是，B-Raf调控血管发育的下游机制(S)尚不清楚。根据我们的初步数据，我们认为B-Raf激酶通过蛋白激酶C(PKC)、信号转导和转录激活因子3(STAT3)和P53调节DNA甲基转移酶(DNMT)和Ten-11转位甲基胞嘧啶双加氧酶(Tet)基因的表达和活性。DNMT和Tet活性的改变导致启动子DNA甲基化的改变，导致调控细胞凋亡的基因如bcl2的表达改变。这些通路在胎儿血管发育中起着至关重要的作用。在这个项目中，我们将检验B-Raf使Bcl2启动子低甲基化以调节胎儿血管干细胞存活的假设。在这三个特定的目标中，我们将研究(1)B-Raf的下游介体，如PKC、STAT3和P53；(2)B-Raf介导的对DNMT和Tet表达和活性的调节；以及(3)B-Raf通过DNMT和Tet对抗凋亡基因bcl2启动子DNA甲基化的调节。这些研究具有很强的创新性和重要意义。目前对DNA甲基化等表观遗传现象的研究还不够深入，从基础科学的角度来看，它具有重要的基础性意义。此外，调节胎儿VSC凋亡的途径参与了几种胎儿和新生儿疾病的发病机制，如生长受限、脑瘫、血管瘤等。从临床的角度来看，这些研究将提供几个治疗靶点，以调节从器官生长和伤口愈合到心肌梗死、脑血管意外(中风)和一般胎儿发育等多种情况下的血管生成和血管增殖。

 DESCRIPTION (provided by applicant): Raf Kinase and Epigenetic Regulation of Fetal Vascular Development. Project Summary Development of the vasculature is a dynamic process that relies on the coordinated expression of numerous genes. The factors that regulate gene expression during blood vessel development are not well defined, however. Our preliminary data and reports from others of impaired vascular development in B-Raf knockout mice have elucidated the significance of this pathway in the developing vasculature. Importantly, downstream mechanism(s) through which B-Raf regulates vascular development are not known. Based on our preliminary data, we propose that B-Raf kinases via Protein Kinase C (PKC), Signal Transducer and Activator of Transcription 3 (STAT3) and p53 regulate DNA methyl Transferase (DNMT) and Ten-Eleven Translocation Methylcytosine Dioxygenase (TET) gene expression and activities. The altered activities of DNMT and TET lead to changes in promoter DNA methylation resulting in altered expression of genes regulating apoptosis such as Bcl2. These pathways play a crucial role in fetal vascular development. In this project, we will test the hypothesis that B-Raf hypomethylates the Bcl2 promoter to regulate fetal vascular stem cell survival. In the three Specific Aims, we will examine the (1) downstream mediators of B-Raf such as PKC, STAT3, and p53 (2) B-Raf-mediated regulation of DNMT and TET expression and activity, and (3) B-Raf-mediated regulation of promoter DNA methylation of the antiapoptotic gene Bcl2 via DNMT and TET. These studies are highly innovative and significant. Kinase-mediated regulation of epigenetic phenomenon such as DNA methylation is not well studied and is of fundamental importance from a basic science perspective. Moreover, pathways regulating fetal VSC apoptosis are involved in the pathogenesis of several fetal and neonatal disorders such as growth restriction, cerebral palsy, hemangioma, etc. From a clinical perspective, these studies will provide several therapeutic targets to regulate angiogenesis and vascular proliferation in many conditions from organ growth and wound healing to disorders such as myocardial infarction, cerebrovascular accident (stroke), and fetal development in general.