Regulation of Venous and Lymphatic Identity by Chromatin-Remodeling

描述（由申请人提供）：表观遗传调节因子在多种发育过程中发挥重要作用，但对它们如何调节血管规格知之甚少。申请人实验室的长期目标是了解atp依赖的染色质重塑复合体如何从表观遗传学上调节导致发育和出生后血管病变的基因转录，例如那些由血液和淋巴管错误规范引起的病变。本研究的目的是了解胚胎发育过程中染色质重塑酶BRG1和CHD4如何影响静脉和淋巴的特性。中心假设是BRG1和CHD4通过调节核受体Coup-TFII的血管表达来影响静脉和淋巴的身份。该假设基于申请人实验室产生的初步数据以及血管Brg1、Chd4和Coup-TFII突变小鼠胚胎之间的表型相似性。Coup-TFII在静脉和淋巴规范中发挥重要作用，但对促进其血管表达的原因尚不清楚。因此，确定调节其表达的表观遗传机制将阐明COUP-TFII如何影响血管发育。将采用两个具体目标来检验中心假设。首先，BRG1和CHD4对静脉和淋巴身份的时间/空间影响将使用一系列遗传工具来识别。突变胚胎中的静脉和淋巴标记物将在整个发育过程中进行分析，以准确确定BRG1和CHD4何时何地影响这些血管。其次，我们将研究BRG1和CHD4对静脉和淋巴管中Coup-TFII表达的表观遗传影响。在Brg1和Chd4突变体中，COUP-TFII的表达将与Aim 1中定义的神经和淋巴特异性表型相关。此外，将使用原代和培养的内皮细胞来验证BRG1和CHD4通过在Coup-TFII启动子处的核小体重塑和组蛋白乙酰化直接促进血管Coup-TFII表达的假设。这项研究具有重要意义，因为它将提供染色质重塑酶如何影响Coup-TFII表达的新信息，并将作为开发操纵Coup-TFII表达的药理学策略的第一步，以积极或消极地影响血管发育。本研究的创新之处在于它强调血管发育的表观遗传调控，这与传统的研究方法有所不同。

DESCRIPTION (provided by applicant): Epigenetic regulators play important roles in a variety of developmental processes, but little is understood about how they modulate vascular specification. A long-term goal of the applicant's laboratory is to understand how ATP-dependent chromatin-remodeling complexes epigenetically regulate transcription of genes that con- tribute to developmental and postnatal vascular pathologies, such as those that arise from misspecification of blood and lymphatic vessels. The objective of this proposal is to understand how the chromatin-remodeling enzymes BRG1 and CHD4 influence venous and lymphatic identity during embryonic development. The cen- tral hypothesis is that BRG1 and CHD4 affect venous and lymphatic identity by modulating vascular expression of the nuclear receptor Coup-TFII. This hypothesis is based on preliminary data produced in the applicant's laboratory and on phenotypic similarities between vascular Brg1, Chd4, and Coup-TFII mutant mouse em- bryos. Coup-TFII plays important roles in venous and lymphatic specification but nothing is known about what promotes its vascular expression. Therefore identification of epigenetic mechanisms for regulating its expres- sion would elucidate how COUP-TFII influences vessel development. Two specific aims will be employed to test the central hypothesis. First, the temporal/spatial impact of BRG1 and CHD4 on venous and lymphatic identity will be discerned using an array of genetic tools. Venous and lymphatic markers in mutant embryos will be analyzed throughout development to determine precisely when and where BRG1 and CHD4 affect these vessels. Secondly, the epigenetic impact of BRG1 and CHD4 on Coup-TFII expression in veins and lymphatics will be examined. COUP-TFII expression in Brg1 and Chd4 mutants will be correlated with the ve- nous and lymphatic specification phenotypes defined in Aim 1. In addition, primary and cultured endothelial cells will be used to test the hypothesis that BRG1 and CHD4 directly promote vascular Coup-TFII expression through nucleosome remodeling and histone acetylation at the Coup-TFII promoter. The proposed research is significant because it will provide novel information about how chromatin-remodeling enzymes affect Coup-TFII expression and will serve as a first step toward developing pharmacological strategies to manipulate Coup-TFII expression in order to positively or negatively influence vascular development. This research is innovative be- cause it emphasizes epigenetic regulation of vascular development, which deviates from traditional ways of approaching this subject.