Direct Reprogramming Improves Cardiac Function and Reverses Fibrosis in Chronic Myocardial Infarction
Direct Reprogramming Improves Cardiac Function and Reverses Fibrosis in Chronic Myocardial Infarction
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DOI：
10.1161/circulationaha.121.058655
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发表时间：
2023-01-17
期刊：
影响因子：
37.8
通讯作者：
Ieda，Masaki
中科院分区：
文献类型：
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作者：
Tani，Hidenori;Sadahiro，Taketaro;Ieda，Masaki
研究背景由于成年心肌细胞再生能力差，心肌梗死（myocardial infarction，MI）后，心肌成纤维细胞（cardiac fibroblasts，CFs）合成细胞外基质，形成纤维化，导致心功能障碍和心力衰竭。目前还缺乏能使心肌再生和逆转慢性心肌梗死纤维化的治疗方法。心肌转录因子Mef 2c/Gata 4/Tbx 5/Hand 2（MGTH）的过表达可直接将CFs重编程为诱导型心肌细胞（iCMs），改善急性MI时的心功能。然而，在体内心脏重编程修复慢性MI与建立scars的能力是undetermined.MethodsWe产生了一种新的Tcf 21 iCre/报告/MGTH 2A转基因小鼠系统中，他莫昔芬治疗可以诱导MGTH和报告表达的居民CFs心脏重编程和成纤维细胞谱系追踪。我们首先在体外和体内测试了这种转基因系统对急性MI的疗效。接下来，我们分别使用Tcf 21 iCre/Tomato/MGTH 2A和Tcf 21 iCre/mTmG/MGTH 2A小鼠分析了慢性MI下的体内心脏重编程和融合事件。微阵列和单细胞RNA测序进行，以确定在体内reprogramming.ResultsWe的心脏修复的机制，证实了转基因在体外和体内心脏重编程急性心肌梗死的疗效。在慢性MI中，体内心脏重编程将102%的驻留CF转化为iCM，其中大多数iCM是通过真正的心脏重编程而不是通过与心肌细胞融合产生的。心脏重编程显著改善了慢性MI患者的心肌收缩并减少了纤维化。微阵列分析显示，MGTH的过度表达激活了心脏程序，同时抑制了慢性MI中的成纤维细胞和炎症特征。单细胞RNA测序表明，居民CF由7个亚群组成，其中促纤维化CF人口增加慢性MI。心脏重编程通过将促纤维化CF转化为静止抗纤维化状态来抑制慢性MI中的成纤维细胞基因表达。MGTH过表达诱导的抗纤维化作用部分通过抑制Meox 1，成纤维细胞activation.ConclusionsThese结果表明，心脏重编程可以修复慢性心肌梗死通过心肌再生和减少纤维化。这些发现为慢性MI和心力衰竭的新疗法的开发提供了机会。
BackgroundBecause adult cardiomyocytes have little regenerative capacity, resident cardiac fibroblasts (CFs) synthesize extracellular matrix after myocardial infarction (MI) to form fibrosis, leading to cardiac dysfunction and heart failure. Therapies that can regenerate the myocardium and reverse fibrosis in chronic MI are lacking. The overexpression of cardiac transcription factors, includingMef2c/Gata4/Tbx5/Hand2(MGTH), can directly reprogram CFs into induced cardiomyocytes (iCMs) and improve cardiac function under acute MI. However, the ability of in vivo cardiac reprogramming to repair chronic MI with established scars is undetermined.MethodsWe generated a novel Tcf21iCre/reporter/MGTH2A transgenic mouse system in which tamoxifen treatment could induce both MGTH and reporter expression in the resident CFs for cardiac reprogramming and fibroblast lineage tracing. We first tested the efficacy of this transgenic system in vitro and in vivo for acute MI. Next, we analyzed in vivo cardiac reprogramming and fusion events under chronic MI using Tcf21iCre/Tomato/MGTH2A and Tcf21iCre/mTmG/MGTH2A mice, respectively. Microarray and single-cell RNA sequencing were performed to determine the mechanism of cardiac repair by in vivo reprogramming.ResultsWe confirmed the efficacy of transgenic in vitro and in vivo cardiac reprogramming for acute MI. In chronic MI, in vivo cardiac reprogramming converted ≈2% of resident CFs into iCMs, in which a majority of iCMs were generated by means of bona fide cardiac reprogramming rather than by fusion with cardiomyocytes. Cardiac reprogramming significantly improved myocardial contraction and reduced fibrosis in chronic MI. Microarray analyses revealed that the overexpression of MGTH activated cardiac program and concomitantly suppressed fibroblast and inflammatory signatures in chronic MI. Single-cell RNA sequencing demonstrated that resident CFs consisted of 7 subclusters, in which the profibrotic CF population increased under chronic MI. Cardiac reprogramming suppressed fibroblastic gene expression in chronic MI by means of conversion of profibrotic CFs to a quiescent antifibrotic state. MGTH overexpression induced antifibrotic effects partly by suppression of Meox1, a central regulator of fibroblast activation.ConclusionsThese results demonstrate that cardiac reprogramming could repair chronic MI by means of myocardial regeneration and reduction of fibrosis. These findings present opportunities for the development of new therapies for chronic MI and heart failure.