Epigenetic control of multipotent cardiac progenitor cell differentiation

多能心脏祖细胞分化的表观遗传控制

• 批准号: 8297158
• 负责人: Zhong Wang
• 金额: $ 41.2万
• 依托单位: MASSACHUSETTS GENERAL HOSPITAL
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-04-01 至 2013-02-18
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8297158
• 关键词: Ablation; Affinity Chromatography; Biological Assay; Cardiac; Cardiac Myocytes; Cell Differentiation process; Cell Lineage; Cell Therapy; Chimera organism; Chromatin; Complex; DNA; Data; Deoxyribonuclease I; Development; Embryo; Endothelial Cells; Epigenetic Process; Gene Targeting; Genetic; Genetic Transcription; Heart; Heart Diseases; Histones; Hypersensitivity; Immunohistochemistry; In Vitro; Knowledge; Ligation; Mediating; Mesoderm Cell; Methylation; Modification; Molecular; Molecular Biology; Multiprotein Complexes; Nucleosomes; Pattern; Play; Positioning Attribute; Process; Recruitment Activity; Regenerative Medicine; Regulation; Right ventricular structure; Role; Smooth Muscle; Stem cells; System; Testing; Therapeutic; Tissues; Ventricular Septal Defects; base; cardiogenesis; cell type; chromatin modification; density; embryonic stem cell; improved; in vivo; insight; loss of function; multipotent cell; novel; programs; promoter; self-renewal; stoichiometry; transcription factor

DESCRIPTION (provided by applicant): The recent identification of cardiac progenitor cells (CPCs) provides a new paradigm for studying and treating heart disease. To realize the full potential of CPCs for therapeutic purposes, it is essential to understand the genetic and epigenetic mechanisms guiding CPC differentiation into cardiomyocytes, smooth muscle, or endothelial cells. At present, our rudimentary knowledge about the epigenetic regulation of lineage differentiation presents a considerable roadblock to developing cell-based therapies. ATP-dependent chromatin remodelers mediate one critical epigenetic mechanism. These large multiprotein complexes open up chromatin to modulate transcription factor access to DNA. SWI/SNF, one of the major types of chromatin remodelers, plays a key role in various aspects of development, including heart development and disease. To decipher SWI/SNF-mediated epigenetic mechanisms in CPC differentiation, we have focused on a key regulatory subunit BAF250a that mediates SWI/SNF assembly/recruitment and controls nucleosome density as well as histone methylation and ubiquitylation. While the SWI/SNF complex and BAF250a are expressed in multiple tissues besides heart, the SWI/SNF complex is uniquely deployed in each tissue to propel tissue-specific differentiation programs. Thus, understanding how a general factor, BAF250a, is utilized to drive the cardiogenic program will instruct us about the steps necessary to direct a multipotent cell into the cardiomyocyte lineage. Indeed, our extensive preliminary data show that BAF250a deletion in second heart field (SHF) caused non-trabeculated right ventricle and ventricular septal defects and embryonic lethality around E13. We have established ESC-based in vitro systems that recapitulate the formation and differentiation of SHF CPCs in vivo and showed that BAF250a ablation in CPCs specifically inhibits cardiomyocyte formation. BAF250a ablation in CPCs also selectively down-regulated the expression of key cardiac transcription factors Mef2c and Nkx2.5 but not Isl1 and Gata4. Thus, we hypothesize that BAF250a-mediated chromatin modifications enable the proper expression of a subset of transcription factors essential for CPC differentiation into cardiomyocytes. Therefore, we propose to determine the function of BAF250a in regulating SHF CPC differentiation (Aim 1), to test the hypothesis that BAF250a is essential for the assembly and recruitment of cSWI/SNF complex to its targets (Aim 2) and to test the hypothesis that BAF250a-mediated epigenetic modifications control CPC differentiation by regulating the promoter accessibility of key cardiac transcription factors (Aim 3). These studies will generate novel insights into epigenetic mechanisms that govern CPC differentiation and may have significant implications in understanding and treating heart disease. PUBLIC HEALTH RELEVANCE: Accomplishing these studies will generate novel insights into epigenetic mechanisms that govern cardiac progenitor cell differentiation. These studies will help identify chromatin marks and transcription and epigenetic factors that can promote specification, self-renewal and differentiation of cardiac progenitor cells and provide candidate targets to improve cardiac stem cell-based therapies.

描述（由申请人提供）：最近对心脏祖细胞（CPC）的鉴定为研究和治疗心脏病提供了新的范例。为了充分发挥 CPC 用于治疗目的的潜力，有必要了解指导 CPC 分化为心肌细胞、平滑肌或内皮细胞的遗传和表观遗传机制。目前，我们对谱系分化的表观遗传调控的基本了解为开发基于细胞的疗法提供了相当大的障碍。 ATP 依赖性染色质重塑因子介导一种关键的表观遗传机制。这些大型多蛋白复合物打开染色质来调节转录因子接触 DNA。 SWI/SNF 是染色质重塑剂的主要类型之一，在发育的各个方面发挥着关键作用，包括心脏发育和疾病。为了破译 SWI/SNF 介导的 CPC 分化表观遗传机制，我们重点研究了一个关键的调节亚基 BAF250a，它介导 SWI/SNF 组装/招募并控制核小体密度以及组蛋白甲基化和泛素化。 虽然 SWI/SNF 复合物和 BAF250a 在心脏以外的多种组织中表达，但 SWI/SNF 复合物在每个组织中都有独特的部署，以推动组织特异性分化程序。因此，了解如何利用一般因子 BAF250a 来驱动心源性程序将指导我们将多能细胞引导至心肌细胞谱系所需的步骤。事实上，我们广泛的初步数据表明，第二心区 (SHF) 中的 BAF250a 缺失导致非小梁化右心室和室间隔缺损以及 E13 左右的胚胎致死。我们建立了基于 ESC 的体外系统，该系统概括了体内 SHF CPC 的形成和分化，并表明 CPC 中的 BAF250a 消融特异性抑制心肌细胞形成。 CPC 中的 BAF250a 消融还选择性下调关键心脏转录因子 Mef2c 和 Nkx2.5 的表达，但不下调 Isl1 和 Gata4。因此，我们假设 BAF250a 介导的染色质修饰能够正确表达 CPC 分化为心肌细胞所必需的转录因子子集。因此，我们建议确定 BAF250a 在调节 SHF CPC 分化中的功能（目标 1），检验 BAF250a 对于 cSWI/SNF 复合物组装和招募至其靶点至关重要的假设（目标 2）并检验该假设BAF250a 介导的表观遗传修饰通过调节关键心脏转录因子的启动子可及性来控制 CPC 分化（目标 3）。这些研究将对控制 CPC 分化的表观遗传机制产生新的见解，并可能对理解和治疗心脏病产生重大影响。 公共健康相关性：完成这些研究将为控制心脏祖细胞分化的表观遗传机制产生新的见解。这些研究将有助于识别染色质标记以及转录和表观遗传因子，这些因子可以促进心脏祖细胞的规范、自我更新和分化，并为改善基于心脏干细胞的疗法提供候选靶标。