Control of cardiomyocyte cell cycle by REST in heart failure and regeneration

在这个研究项目中，我们打算研究re1沉默转录的分子机制。 因子(REST)通过小鼠遗传学、分子生物学的协同方法调节心肌细胞周期 和系统生物学。我们的最终目标是确定潜在的治疗目标，通过以下方式对抗心脏病 促进心肌细胞增殖，修复受损的成人心脏。成人心脏的修复有限 能力，因为大多数成年心肌细胞是非分裂细胞。用于成人心脏再生，通过预 现有的心肌细胞，我们需要了解心肌细胞的增殖是如何控制的，是什么群体 心肌细胞维持增殖潜能，无论心肌细胞的发育机制 在有病的条件下，如果可以进一步执行，扩散就会重新激活。在这里，我们计划 通过研究小鼠心脏的休息功能来解决这些问题，因为我们最近的研究已经 REST是胚胎心脏所需的一种新的心肌细胞增殖内在调节因子 发育与新生儿心脏再生。REST抑制细胞周期抑制物p21以维持 心肌细胞周期。几个关键的细胞周期激活物的表达也需要REST。基座 根据这些发现，我们假设，上调休息时间可能通过以下方式促进受伤心脏的更新 调节细胞周期基因和调节因子的表达，促进心肌细胞增殖。我们会 在两个目标上检验这一假设。目标1将确定心力衰竭患者的强迫休息表现 促进心肌细胞周期，改善疾病结局。我们将特别停用Rest in 心肌细胞，有或没有p21失活，以及强迫静息表达，以确定 成人心脏修复是否需要休息。Aim 2将研究REST如何控制心肌细胞 研究和比较正常心脏和衰竭心脏的静息调节网络 (MYH6)和未成熟(MYH7)心肌细胞。我们还将研究REST监管网络 确定不同染色质辅助因子对基因激活或抑制的剩余募集。这将是 通过使用细胞类型特异性、全基因组静止染色质免疫沉淀测序来实现 (ChIP-seq)和转录组学(RNA-seq)比较正常或损伤的MYH6和MYH7心肌细胞 红心。老鼠发现的人类相关性将通过关键休息的功能研究来确定- 人可诱导多能干细胞来源的心肌细胞增殖调控基因 (IPSC)。通过完成这个项目，我们将确定REST在促进心肌细胞方面的作用 增殖以改善衰竭成人心脏的更新和功能。我们还会学到一种基因 REST调节成人心肌细胞周期和识别新靶点的调控网络 改善心肌细胞增殖以促进心脏再生。这一新信息将推动我们的 了解心脏生物学，为治疗心力衰竭提供新的方向。

In this research project, we propose to study the molecular mechanisms by which RE1 silencing transcription factor (REST) regulates cardiomyocyte cell cycle using synergistic approaches of mouse genetics, molecular and systems biology. Our ultimate goal is to identify potential therapeutic targets to combat heart disease by promoting cardiomyocyte proliferation to repair the injured adult heart. The adult heart has a limited repairing capacity, because most adult cardiomyocytes are non-dividing cells. For adult heart regeneration by pre- existing cardiomyocytes, we need to understand how cardiomyocyte proliferation is controlled, what population of cardiomyocytes maintains proliferation potential, whether developmental mechanisms of cardiomyocyte proliferation are re-activated under diseased conditions, and if they can be further enforced. Here we plan to address these questions by investigating REST functions in the mouse heart, because our recent studies have identified REST as a new intrinsic regulator of cardiomyocyte proliferation required for embryonic heart development and neonatal heart regeneration. REST represses the cell cycle inhibitor p21 to maintain cardiomyocyte cell cycling. REST is also required for the expression of several key cell cycle activators. Based on these findings, we hypothesize that upregulation of REST may improve the renewal of the injured heart by modulating the expression of cell cycle genes and regulators to promote cardiomyocyte proliferation. We will test this hypothesis in two aims. Aim 1 will determine whether forced REST expression in failing hearts promotes cardiomyocyte cell cycle and improves the disease outcome. We will specifically inactivate REST in the cardiomyocytes, with or without the p21 inactivation, as well as forced REST expression, to determine whether REST is required for adult heart repair. Aim 2 will investigate how REST controls cardiomyocyte cell cycle in normal and failing hearts by studying and comparing the REST regulatory network in the mature (MYH6+) and immature (MYH7+) cardiomyocytes. We will also study the REST regulatory network by determining the REST recruitment of different chromatin co-factors for gene activation or repression. This will be achieved by using the cell-type specific, genome wide REST chromatin immunoprecipitation sequencing (ChIP-seq) and transcriptomics (RNA-seq) for MYH6+ versus MYH7+ cardiomyocytes from normal or injured hearts. The human relevance of mouse findings will be ascertained by the functional study of key REST- regulated genes in the proliferation of cardiomyocytes derived from the human inducible pluripotent stem cells (iPSC). By completing this project, we will have determined the REST role in promoting cardiomyocyte proliferation to improve the renewal and function of failing adult hearts. We will have also learned a genetic regulatory network by which REST regulates adult cardiomyocyte cell cycle and identified new targets for improving cardiomyocyte proliferation for heart regeneration. The new information will advance our understanding of cardiac biology and provide a new direction to treat heart failure.