Critical Role of TBX20 in Cardiomyocyte Maturation during Direct Cardiac Reprogramming

总结 直接心脏重编程以从成纤维细胞产生诱导心肌细胞（iCM）已经成为一种新的方法。 心力衰竭仍然是死亡的主要原因， 发达国家的发病率。虽然关于从小鼠细胞产生的iCM已知很多， 直接心脏重编程对人类细胞的适应受到效率低和质量差的阻碍 因为物种之间的内在差异。我们最近报道了单细胞转录组学分析 在人类心脏重编程过程中，发现iCM生成不足与 与欠发达的基因程序，如离子通道和细胞连接，这表明，额外的 可能需要调节心肌细胞功能的重编程因子。在这项研究计划中，我们 一种新的重编程因子TBX20在产生心肌细胞特性中起重要作用的假设 通过建立与心肌细胞功能相关的基因程序。为了支持我们的假设， 初步数据显示TBX20在人iCM中大部分表达不足。虽然被迫表达 TBX20的加入显著提高了重编程效率，并伴随着基因程序的激活。 与心肌细胞功能有关。为了检验假设，我们建议1）进一步确定影响 TBX20对直接人类心脏重编程的影响，以及2）确定TBX20如何作为一种重要的 在这个过程中的重编程因素。本建议的主要目标是确定以下方面的关键作用： TBX 20对直接心脏重编程过程中心肌细胞再生的影响完成这一 该提案不仅将提供关于心肌细胞身份如何通过直接再生的机制见解， 心脏重编程，而且使我们能够直接从人类产生功能可靠的心肌细胞。 非心肌细胞的心脏修复

SUMMARY Direct cardiac reprogramming to generated induced cardiomyocytes (iCMs) from fibroblasts has emerged as a promising therapeutic strategy for the treatment of heart failure, which is still the leading cause of mortality and morbidity in the developed country. While much is known regarding iCMs generated from mouse cells, the adaptation of direct cardiac reprogramming to human cells is hurdled with low efficiency and poor quality because of intrinsic differences between species. We recently reported the single cell transcriptomic analysis during human cardiac reprogramming and discovered that the insufficient generation of iCMs is associated with underdeveloped gene programs, such as ion channel and cell junction, suggesting that additional reprogramming factors regulating function of cardiomyocytes might be required. In this research program, we hypothesis that a novel reprogramming factor TBX20 plays an essential role to generate cardiomyocyte identity by establishing gene programs associated with cardiomyocyte function. In support of our hypothesis, our preliminary data have shown that TBX20 is largely under-expressed in human iCMs. While forced expression of TBX20 significantly enhanced reprogramming efficiency accompanied with activation of gene programs associated with cardiomyocyte function. To test the hypothesis, we propose to 1) further determine the impact of TBX20 on direct human cardiac reprogramming and 2) determine how TBX20 functions as an essential reprogramming factor during this process. The main objective of this proposal is to identify the critical role of TBX20 on regeneration of cardiomyocytes during direct cardiac reprogramming. The completion of this proposal will not only provide mechanistic insight into how cardiomyocyte identity can be regenerated by direct cardiac reprogramming but also enable us to generate functional-reliable cardiomyocytes directly from human non-myocytes for potential heart repair.