Recording the cellular origins of cardiac regeneration

项目摘要 人的心脏在受伤后不能再生，而是用僵硬的肌肉替代受损的肌肉心肌。 减少心输出量的疤痕组织。促进心肌细胞（CMs）的增殖，以补充损伤 心肌代表了改善生活质量和预防过早死亡的一种有前途的策略。 心肌梗死康复中的患者。迄今为止，再生疗法的尝试未能促进 有意义的心肌恢复。治疗策略的一个有前途的来源涉及以下研究： 具有再生心脏组织的固有能力的脊椎动物，包括斑马鱼模式生物。研究 将非再生哺乳动物的心脏损伤反应与斑马鱼进行比较是困难的，然而， 巨大的进化差异因此，需要进行更多与进化相关的比较， 区分再生和非再生物种的细胞行为。该提案描述了 旨在确定促进心脏再生的独特遗传和细胞特征的实验， 通过与青鳉鱼（一种非再生硬骨鱼）的比较，对斑马鱼进行了研究。第一个目标是 根据奖学金计划，我将在斑马鱼和青鳉中生成心脏损伤反应的全器官细胞图谱 在几个时间点通过单细胞RNA测序。对这些数据集的分析将揭示关键细胞 在再生和非再生物种中，类型的基因表达模式不同。第二个目标， 我利用最近开发的单细胞谱系追踪技术来重建细胞的谱系关系 参与了斑马鱼心脏的再生。这些实验将提供一个全面的看法， CM和免疫细胞被激活以恢复受损组织。在最后的目标，我将测试的假设， 响应免疫细胞的细胞自主行为促进斑马鱼心脏再生。我会化验 斑马鱼和斑马鱼之间造血干细胞相互移植后的心脏再生 青鳉，揭示免疫细胞功能是否足以赋予再生潜力。所有这些 实验将为确定确切的细胞群和基因表达提供重要的步骤， 介导心脏再生的模式，并有可能帮助开发靶向治疗 可以促进人类心脏再生

Project Summary Human hearts fail to regenerate after injury, instead replacing injured regions of muscular myocardium with rigid scar tissue that impairs cardiac output. Promoting the proliferation of cardiomyocytes (CMs) to replenish injured heart muscle represents a promising strategy for improving the quality of life and preventing premature death of patients recovering from myocardial infarction. Attempts at regenerative therapies have thus far failed to promote meaningful restoration of lost myocardium. A promising source of therapeutic strategies involves the study of vertebrates with the inherent ability to regenerate cardiac tissue, including the zebrafish model organism. Studies comparing the cardiac injury response in non-regenerating mammals to zebrafish are made difficult, however, by vast evolutionary divergence. More evolutionarily relevant comparisons are therefore needed to determine the cellular behaviors that differentiate regenerating and non-regenerating species. This proposal describes experiments aimed at identifying the unique genetic and cellular features that facilitate cardiac regeneration in zebrafish through comparisons with medaka, a non-regenerating teleost fish species. In the first aim of this fellowship proposal, I will generate organ-wide cell atlases of cardiac injury response in zebrafish and medaka over several time points through single-cell RNA sequencing. Analyses of these datasets will reveal how key cell types differ in their gene expression patterns in regenerating and non-regenerating species. In the second aim, I utilize a recently developed single-cell lineage tracing technique to reconstruct the lineage relationships of cells participating in cardiac regeneration in zebrafish. These experiments will provide a comprehensive view of which CMs and immune cells are activated to restore injured tissue. In the final aim, I will test the hypothesis that the cell-autonomous behaviors of responding immune cells facilitate cardiac regeneration in zebrafish. I will assay heart regeneration following reciprocal transplantations of hematopoietic stem cells between zebrafish and medaka, revealing whether immune cell functions are sufficient to impart regenerative potential. Together, these experiments will provide important steps toward identifying the exact cell populations and gene expression patterns that mediate cardiac regeneration and have the potential to aid in the development of targeted therapies that promote cardiac regeneration in humans.