The Role of Runx1 in Cardiomyocyte Cell Cycle and Ploidy

项目总结 心血管疾病仍然是全球主要的死亡原因，因此有必要继续研究 开发新的治疗策略。在历史上，成年哺乳动物心肌细胞(CMS)被认为是 有丝分裂后，因此不能在损伤后再生心肌。然而，近年来， 科学家已经证明，成年哺乳动物CM能够进行少量的增殖，尽管这 能力可能仅限于心肌细胞的一小部分。Patterson et.Al演示了使用 稀有单核二倍体心肌细胞比例较高的杂交小鼠多样性小组 (MNDCM)与心肌梗死后功能改善、瘢痕缩小和CM增殖增强有关 脑梗塞。随之而来的全基因组关联分析确定了与 MNDCM人口的频率。从这个筛选中出来的一个基因是RUNX1。并发，RUNX1 由于它在疾病状态下的存在增加，引起了心脏再生研究人员的注意， 一些人认为它可能是去分化(胎儿基因诱导)的标志。特定于CM RUNX1的过表达导致MNDCM群体翻了一番，从而验证了其对 人口。通过包括出生后发育和成人损伤在内的多种背景，敲除RUNX1 当过表达RUNX1时，DNA合成减少，而RUNX1增加DNA合成。此外，首字母 RNA测序数据分析表明，RUNX1在新生小鼠中过表达上调 已知的胎儿CM基因和CM细胞周期活性标志物。这些初步数据得到了 文献表明，在许多其他组织中，转录因子RUNX1直接调节许多 与细胞周期相关的基因，表明RUNX1的S作用可能在不同类型的细胞中高度保守。 这项研究的中心假设是RUNX1通过转录调节CM对心力衰竭的反应 胎儿基因和细胞周期活性的诱导。为了测试这一想法，这里提出的工作将利用两个增益- 和功能丧失的RUNX1小鼠模型，由CM特异的CRE暂时控制。AIM 1将调查 RUNX1对心肌梗死后预后和CM细胞周期的影响目标2将评估转录控制 RUNX1通过两种互补的基因组范围的方法：RNA测序和切割&标签。结果来自 这项研究将进一步促进该领域对心脏手术过程中所涉及的遗传成分的理解 并改进今后的治疗策略。

PROJECT SUMMARY Cardiovascular disease remains the leading cause of death worldwide, necessitating continued research to develop novel therapeutic strategies. Historically, adult mammalian cardiomyocytes (CMs) were thought to be post-mitotic and therefore unable to regenerate the myocardium after injury. However, in recent years, scientists have shown that the adult mammalian CM is capable of a small amount of proliferation, though this competence is potentially restricted to a subset of cardiomyocytes. Patterson et. al demonstrated using the hybrid mouse diversity panel that having greater percentages of the rare mononuclear diploid cardiomyocyte (MNDCM) is associated with improved function, smaller scars, and enhanced CM proliferation after myocardial infarction. An accompanying genome-wide association analysis identified genetic loci associated with the frequency of the MNDCM population. One gene to come out of this screen was Runx1. Concurrently, RUNX1 captured the attention of cardiac regeneration researchers due to its increased presence in disease states, with some suggesting it may be a marker for dedifferentiation (fetal gene induction). CM-specific overexpression of Runx1 results in a doubling of the MNDCM population, thereby validating its influence on the population. Via multiple contexts including postnatal development and adult injury, knocking out Runx1 decreases DNA synthesis while overexpressing Runx1 increases DNA synthesis. Furthermore, an initial analysis of RNA sequencing data demonstrates that RUNX1 overexpression in a neonatal mouse upregulates known fetal CM genes and markers of CM cell cycle activity. These preliminary data are supported by the literature, which has shown in many other tissues that RUNX1, a transcription factor, directly regulates many genes associated with the cell cycle, indicating that RUNX1's role may be highly conserved across cell types. The central hypothesis of this study is that Runx1 regulates the CM response to heart failure via transcriptional induction of fetal genes and cell cycle activity. To test this idea the work proposed here will utilize both gain- and loss-of-function Runx1 mouse models temporally controlled by a CM-specific Cre. Aim 1 will investigate the effect of Runx1 on post-infarction outcomes and CM cell cycle. Aim 2 will assess transcriptional control of RUNX1 through two complementary genome-wide approaches: RNA sequencing and CUT&Tag. Results from this study will further advance the field's understanding of the genetic components involved during a cardiac injury and improve future treatment strategies.