Cardiac lineage determination and nuclear architecture

心脏谱系测定和核结构

• 批准号: 10449605
• 负责人: Jonathan A. Epstein
• 金额: $ 3.57万
• 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/10449605
• 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.

该 R35 应用程序提出了一个概念框架，其中包含 PI 过去所做的工作主体 20年被用作开展创新研究的基础，旨在融合尖端技术 了解核结构（染色质如何在细胞核的三个维度上组织）以产生 谱系决定和细胞命运身份的新范式的目标是更好地理解其广泛性。 表征细胞身份的基因表达程序受到调节，以告知再生 初步数据表明基因组区域是局部的。 核外围（称为“核纤层蛋白相关结构域”或 LAD）被特定的组蛋白标记沉默， 包括H3K9me2，并且这些区域在谱系确定后从外围释放，以便 允许同时激活整个基因程序 数据表明 H3K9me2 标记。 LAD 的特征通过有丝分裂被“记住”，为谱系的表观遗传记忆提供了机制 所提出的模型表明，定义 LAD 的表观遗传标记（例如 H3K9me2）是相同的。 被介导空间定位的“LAD-tethers”识别，并且这些组蛋白表位可以被“屏蔽” 通过组蛋白尾部相邻氨基酸残基的磷酸化（包括 H3S10 和 H3S10 的磷酸化） H3T11）。我们建议测试在有丝分裂过程中，磷酸化 H3S10 的极光 B 激酶的作用，以解除束缚。 LADs 通过屏蔽 H3K9me2 表位，允许释放 LADs，随后破坏核 膜和 DNA 复制，然后去除 S10 磷酸化并重建 LAD，如下所示 子核膜在暴露的组蛋白标记周围形成，因此，如果全基因组模式。 给定细胞中的 LAD 通过代表沉默的替代谱系程序的“代码”来定义其身份，然后 细胞身份可以通过有丝分裂被记住并在子细胞中有效地重建。 用于重编程、转分化、不对称细胞分裂和谱系身份的稳定性（因此 癌症易感性）将被探索调节细胞的巨大变化的信号转导级联。 代谢和功能（例如葡萄糖和脂肪酸代谢特征之间的转换） 发育中和患病的心肌细胞和癌细胞）可能会影响核结构和 LAD 动力学 通过聚合包括 H3T11 在内的组蛋白残基的磷酸化，这一观点得到了已发表的文章的支持。 数据表明与代谢变化有关的丙酮酸激酶的核形式可以磷酸化 H3T11 可以与 Hdac3 相互作用，我们已经证明 Hdac3 是 LAD 系链，导致表观遗传变化和 因此，该提案提供了为以下方面提供实验支持的机会。 整合染色质三维​​调控的基因调控和细胞身份模型 细胞核内的包装扩展了我们对细胞身份的理解并提供了一种新的机制 了解整个基因程序的协调调节方式。