Recording the cellular origins of cardiac regeneration

项目摘要 人的心脏在受伤后不能再生，而是用僵硬的肌肉取代受损的肌肉 损害心输出量的疤痕组织。促进心肌细胞增殖以补充受损心肌细胞 心肌是一种有希望的策略，可以提高生活质量和防止过早死亡 从心肌梗死中恢复的患者。到目前为止，再生疗法的尝试未能推广 对丢失的心肌有意义的恢复。治疗策略的一个很有希望的来源是研究 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 然而，比较非再生哺乳动物和斑马鱼的心脏损伤反应是困难的，然而， 通过巨大的进化差异。因此，需要更多与进化相关的比较来确定 区分再生物种和非再生物种的细胞行为。这份提案描述了 旨在确定促进心脏再生的独特遗传和细胞特征的实验 斑马鱼通过与青竹进行比较，青竹是一种非再生的硬骨鱼。在这个项目的第一个目标中 奖学金提案，我将制作斑马鱼和青竹心脏损伤反应的器官范围细胞图谱 通过单细胞RNA测序在几个时间点上。对这些数据集的分析将揭示关键细胞如何 在再生和非再生物种中，类型的基因表达模式不同。在第二个目标中， 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 参与斑马鱼心脏再生。这些实验将提供一个全面的视角， CMS和免疫细胞被激活，以恢复受损组织。在最终目标中，我将测试假设 应答免疫细胞的细胞自主行为促进了斑马鱼的心脏再生。我会化验 斑马鱼和斑马鱼之间造血干细胞相互移植的心脏再生 青竹，揭示免疫细胞功能是否足以赋予再生潜力。加在一起，这些 实验将为确定确切的细胞群体和基因表达提供重要的步骤 介导心脏再生的模式，并有可能有助于靶向治疗的开发 能促进人类心脏再生的物质。

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.