Understanding the Cardiac Benefits of Exercise at the Cellular and Molecular Level

项目摘要/摘要 心力衰竭(HF)是发病率和死亡率的一个日益增长的原因。尽管有最好的治疗方法， 许多心力衰竭患者的预后仍然很差，这突显了对新的心力衰竭疗法的临床需求尚未得到满足。 这一杰出调查者奖的申请灵感来自于一项观察，即锻炼保护 心脏，促进心肌细胞(CM)的存活和增殖，同时减少纤维化和炎症。还没有 我们对负责任的机制知之甚少，也不知道它们是否可以用于治疗。这里, 我计划利用NHLBI R35卓越产品提供的长期支持和科学灵活性 研究人员奖阐明运动对心脏有益的细胞和分子基础 在临床前模型中验证潜在的新治疗靶点。我们发现，虽然锻炼和 病理性应激均可导致心肌肥大，运动诱发心肌肥大的机制 肥大在很大程度上是不同的，并且矛盾地保护心脏，而不是导致不利的后遗症。 (《细胞》，2010)。我们还发现，运动显著增强了成年人的内源性心肌生成 哺乳动物心脏(《自然通讯》，2018)。在某些情况下，模仿运动中看到的变化不仅 预防但可以逆转已建立的心衰(科学翻译Med.，2019)。在这里，我们提出一个广泛的计划 为了描述运动的细胞和分子效应，定义调节机制的通路 运动的心肌发生和其他益处，并探索这些途径的翻译潜力 在临床前模型中。在心肌细胞和非心肌细胞中描述心脏对运动的适应性反应 心肌细胞，一系列无偏见的发现工具将被使用，包括单核RNA- 测序(SnRNA-seq)、散装RNA-seq和转座酶可及染色质分析(atac-seq)。 SnRNA-seq将提供对运动反应中特定细胞系基因表达变化的洞察。 随着时间的推移，这种方法将与特定血统的功能获得和丧失模型相结合，以帮助 定义小区类型之间的串扰。将使用几种标注工具来帮助识别划分 CMS在SnRNA-seq研究中描述了这一动态过程，并测试了特定的假设 心肌发生需要CMS和/或许可环境的亚群。统计学上讲 将使用相关的体外细胞筛选出具有保护和心肌生成作用的强健候选细胞 培养和体内斑马鱼模型。最有希望的研究将在临床前小鼠和猪身上进行 发现新的生物途径和开发新的治疗方法的模型。R35机制 独一无二地提供所需的灵活性和时间框架，以支持建议的无偏见发现和 生物信息学分析和独特动物模型的产生。成功完成此计划 将促进我们对心肌发生和运动对心脏的有益影响的理解，而 描绘可能减轻心力衰竭的途径，从而满足紧迫的临床需求。

Project Summary/Abstract Heart failure (HF) is a growing cause of morbidity and mortality. Despite the best available treatments, prognosis remains poor for many HF patients underscoring the unmet clinical need for new HF therapies. This Outstanding Investigator Award application is inspired by the observation that exercise protects the heart, promoting cardiomyocyte (CM) survival and proliferation while reducing fibrosis and inflammation. Yet we understand little of the responsible mechanisms and whether they can be exploited therapeutically. Here, I plan to leverage the longer-term support and scientific flexibility afforded by the NHLBI R35 Outstanding Investigator Award to illuminate the cellular and molecular basis of the cardiac benefits of exercise and to validate potential new therapeutic targets in preclinical models. We discovered that although exercise and pathological stress both induce cardiac hypertrophy, the mechanisms underlying exercise-induced hypertrophy are largely distinct and, rather than leading to adverse sequelae, paradoxically protect the heart (Cell, 2010). We also found that exercise dramatically enhances endogenous cardiomyogenesis in the adult mammalian heart (Nature Comm., 2018). In some cases, mimicking the changes seen in exercise not only prevents but can reverse established HF (Science Transl. Med., 2019). Here we propose a broad program to delineate the cellular and molecular effects of exercise, define the mechanistic pathways mediating cardiomyogenesis and other benefits of exercise, and explore the translational potential of these pathways in preclinical models. To describe the heart’s adaptive response to exercise in cardiomyocytes and non- cardiomyocytes, a range of unbiased discovery tools will be employed including single nucleus RNA- sequencing (snRNA-seq), bulk RNA-seq, and Assay for Transposase-Accessible Chromatin (ATAC-seq). snRNA-seq will provide insight into cell lineage-specific changes in gene expression in response to exercise over time, and this approach will be combined with lineage-specific gain- and loss-of-function models to help define crosstalk between cell types. Several labeling tools will be used to facilitate identification of dividing CMs in snRNA-seq studies to profile this dynamic process and test the hypotheses that specific subpopulations of CMs and/or permissive environments are required for cardiomyogenesis. Statistically robust candidates will be screened for protective and cardiomyogenic effects using relevant in vitro cell culture and in vivo zebrafish models. The most promising will be studied in preclinical murine and porcine models to uncover new biological pathways and develop new therapeutic approaches. The R35 mechanism uniquely provides the flexibility and timeframe required to support the proposed unbiased discovery and bioinformatic analyses and the generation of unique animal models. Successful completion of this program will advance our understanding of cardiomyogenesis and the beneficial effects of exercise in the heart, while delineating pathways with the potential to mitigate heart failure, thus meeting a pressing clinical need.