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: 8448103
• 负责人: Zhong Wang
• 金额: $ 37.01万
• 依托单位: UNIVERSITY OF MICHIGAN AT ANN ARBOR
• 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 2017-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8448103
• 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.

描述（由申请人提供）：心脏祖细胞（CPC）的最新鉴定提供了用于研究和治疗心脏病的新范式。为了实现用于治疗目的的CPC的全部潜力，必须了解将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，我们对谱系分化表观遗传调节的基本知识为开发基于细胞的疗法的障碍带来了相当大的障碍。 ATP依赖性染色质改塑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，以调节转录因子访问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（包括心脏发育和疾病）中起着关键作用。为了解解CPC分化中的SWI/SNF介导的表观遗传机制，我们专注于介导SWI/SNF组装/募集的关键调节亚基BAF250A，并控制核小体密度以及组蛋白甲基化和泛素化。 尽管SWI/SNF复合物和BAF250A在心脏以外的多个组织中表达，但SWI/SNF复合物在每个组织中唯一部署以推动组织特异性分化程序。因此，了解一般因素BAF250A是如何利用驱动心源程序的如何将多能细胞引导到心肌细胞谱系所需的步骤的。确实，我们广泛的初步数据表明，第二心脏场（SHF）中的BAF250A缺失导致未牵引的右心室和心室中隔缺陷和E13附近的胚胎致死性。我们已经建立了基于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消融特异性抑制了心肌细胞的形成。 CPC中的BAF250A消融还选择性地下调了关键心脏转录因子MEF2C和NKX2.5的表达，但不是ISL1和GATA4。因此，我们假设BAF250A介导的染色质修饰使CPC分化为心肌细胞必不可少的转录因子的子集适当地表达。因此，我们建议确定BAF250A在调节SHF CPC差异化（目标1）中的功能，以测试BAF250A对于将CSWI/SNF复合物组装和募集到其目标的组装和募集至关重要的假设（AIM 2），并测试BAF250A介导的启动次数的促进次数的启动次数的启动因素（AIM 2） 3）。这些研究将产生对控制CPC分化的表观遗传机制的新见解，并可能对理解和治疗心脏病具有重要意义。