Cardiac lineage determination and nuclear architecture

心脏谱系测定和核结构

• 批准号: 10329887
• 负责人: Jonathan A. Epstein
• 金额: $ 95.8万
• 依托单位: UNIVERSITY OF PENNSYLVANIA
• 依托单位国家: 美国
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-01-01 至 2024-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10329887
• 关键词: 3-Dimensional; Amino Acids; Architecture; Cardiac; Cardiac Myocytes; Cardiovascular Diseases; Cardiovascular system; Cell Nucleus; Cell division; Cells; Characteristics; Chromatin; Code; Complex; DNA; DNA biosynthesis; Data; Daughter; Epigenetic Process; Epitopes; Excision; Foundations; Gene Expression; Gene Expression Regulation; Genes; Genome; Glucose; Goals; Heart Diseases; Histones; Lamins; Malignant Neoplasms; Mediating; Metabolic; Metabolism; Mitosis; Modeling; Myocardial Infarction; Nuclear; Nuclear Envelope; Nuclear Inner Membrane; Pattern; Phosphorylation; Predisposition; Publishing; Pyruvate Kinase; Regulation; Scientist; Signal Transduction; Tail; Testing; aurora B kinase; cancer cell; cardiac regeneration; daughter cell; epigenetic memory; fatty acid metabolism; genome-wide; genomic locus; innovation; novel; programs; regenerative approach; regenerative therapy; stem cells; transdifferentiation

This R35 application proposes a conceptual framework in which a body of work produced by the PI over the past 20 years is utilized as the foundation for launching innovative studies that seek to incorporate cutting edge understanding of nuclear architecture (how chromatin is organized in three dimensions in the nucleus) to produce a novel paradigm of lineage determination and cell fate identity. The goal is to better understand how broad gene expression programs that characterize cell identity are regulated in order to inform regenerative approaches to cardiovascular disease. Preliminary data suggest that regions of the genome that are localized to the nuclear periphery (called “lamin associated domains” or LADs) are silenced by specific histone marks, including H3K9me2, and that these regions are released from the periphery upon lineage determination in order to allow for simultaneous activation of entire gene programs. Data suggests that the H3K9me2 mark characteristic of LADs is “remembered” through mitosis providing a mechanism for epigenetic memory of lineage identity. The proposed model suggests that epigenetic marks such as H3K9me2 that define LADs are recognized by “LAD-tethers” that mediate spatial localization, and that these histone epitopes can be “shielded” by phosphorylation of adjacent amino acid residues of the histone tails (including phosphorylation of H3S10 and H3T11). We propose to test that during mitosis, aurora B kinase which phosphorylates H3S10, acts to un-tether LADs by shielding the H3K9me2 epitope, allowing for the release of LADs, subsequent breakdown of the nuclear membrane and DNA replication, followed by removal of S10 phosphorylation and re-establishment of LADs as the daughter nuclear membranes form around the exposed histone mark. Thus, if the genome-wide pattern of LADs in a given cell defines its identity by representing a “code” of silenced alternative lineage programs, then cellular identity can be remembered through mitosis and efficiently re-established in daughter cells. Implications for reprogramming, trans-differentiation, asymmetric cell division, and stability of lineage identity (and thus cancer susceptibility) will be explored. Signal transduction cascades that regulate dramatic changes in cellular metabolism and function (such as the switch between glucose and fatty acid metabolism characteristic of developing and ailing cardiac myocytes and of cancer cells) may impact nuclear architecture and LAD dynamics by converging on phosphorylation of histone residues including H3T11. This notion is supported by published data indicating that a nuclear form of pyruvate kinase that is implicated in metabolic shifts can phosphorylate H3T11 and can interact with Hdac3 which we have shown is a LAD tether, resulting in epigenetic changes and activation of specific gene loci. Thus, this proposal provides the opportunity to provide experimental support for a model of gene regulation and cellular identity that incorporates three dimensional regulation of chromatin packaging within the nucleus extending our understanding of cellular identity and providing a novel mechanism to understand the way in which entire gene programs are coordinately regulated.

此R35应用程序提出了一个概念框架，其中PI过去生产的作品 20年被用作启动创新研究的基础，试图融合最前沿 了解核结构（如何在细胞核中的三个维度组织染色质）产生 谱系确定和细胞命运身份的新型范式。目标是更好地了解 调节表征细胞身份的基因表达程序，以告知再生 心血管疾病的方法。初步数据表明，基因组的本地化区域 特定组蛋白标记沉默到核周围（称为“层lamin相关结构域”或LAD）的核周围。 包括H3K9Me2，并且在谱系确定按顺序确定时将这些区域从外围释放 允许简单激活整个基因程序。数据表明H3K9me2标记 LAD的特征是通过有丝分裂提供了表观遗传记忆的机制 身份。提出的模型表明，定义LAD的表观遗传标记，例如H3K9me2 通过介导空间定位的“ lad-tethers”认可，这些组蛋白表位可以“屏蔽” 通过组蛋白尾巴的相邻氨基酸残基的磷酸化（包括H3S10和 H3T11）。我们建议测试在有丝分裂期间，光颗粒化H3S10的Aurora B激酶作用于无束 通过屏蔽H3K9me2 episodeTope，允许释放小伙子，随后破裂核 膜和DNA复制，然后去除S10磷酸化并重新建立小伙子 女儿核膜周围形成了暴露的组蛋白标记。那，如果全基因组模式的模式 给定单元格中的小伙子通过表示沉默的替代血统程序的“代码”来定义其身份，然后 可以通过有丝分裂记忆细胞身份，并有效地在子细胞中重新建立。含义 用于重编程，反差异，不对称细胞分裂以及谱系身份的稳定性（因此 将探索癌症的敏感性）。信号翻译级联，调节细胞的急剧变化 代谢和功能（例如葡萄糖和脂肪酸代谢之间的切换的特征 发育和疾病的心肌细胞和癌细胞）可能会影响核结构和LAD动力学 通过在包括H3T11在内的组蛋白保留率的磷酸化中融合。这个概念得到了已发布的支持 数据表明在代谢转移中实现的丙酮酸激酶的核形式可以磷酸化 H3T11并可以与HDAC3相互作用，我们显示的是LAD系绳，导致表观遗传变化和 特定基因基因座的激活。这就是该提议提供了为实验支持的机会 基因调控和细胞身份的模型，该模型结合了染色质的三维调节 核内包装，扩展了我们对细胞身份的理解并提供了新的机制 了解整个基因程序的协调方式。