PDF(Pubmed)
Abstract：
Cardiac fibrosis is a pathological scarring process that impairs cardiac function. N-acetyltransferase 10 (Nat10) is recently identified as the key enzyme for the N4-acetylcytidine (ac4C) modification of mRNAs. In this study, we investigated the role of Nat10 in cardiac fibrosis following myocardial infarction (MI) and the related mechanisms. MI was induced in mice by ligation of the left anterior descending coronary artery; cardiac function was assessed with echocardiography. We showed that both the mRNA and protein expression levels of Nat10 were significantly increased in the infarct zone and border zone 4 weeks post-MI, and the expression of Nat10 in cardiac fibroblasts was significantly higher compared with that in cardiomyocytes after MI. Fibroblast-specific overexpression of Nat10 promoted collagen deposition and induced cardiac systolic dysfunction post-MI in mice. Conversely, fibroblast-specific knockout of Nat10 markedly relieved cardiac function impairment and extracellular matrix remodeling following MI. We then conducted ac4C-RNA binding protein immunoprecipitation-sequencing (RIP-seq) in cardiac fibroblasts transfected with Nat10 siRNA, and revealed that angiomotin-like 1 (Amotl1), an upstream regulator of the Hippo signaling pathway, was the target gene of Nat10. We demonstrated that Nat10-mediated ac4C modification of Amotl1 increased its mRNA stability and translation in neonatal cardiac fibroblasts, thereby increasing the interaction of Amotl1 with yes-associated protein 1 (Yap) and facilitating Yap translocation into the nucleus. Intriguingly, silencing of Amotl1 or Yap, as well as treatment with verteporfin, a selective and potent Yap inhibitor, attenuated the Nat10 overexpression-induced proliferation of cardiac fibroblasts and prevented their differentiation into myofibroblasts in vitro. In conclusion, this study highlights Nat10 as a crucial regulator of myocardial fibrosis following MI injury through ac4C modification of upstream activators within the Hippo/Yap signaling pathway.
摘要：
心脏纤维化是损害心脏功能的病理性瘢痕形成过程。N-乙酰转移酶10（Nat10）最近被认为是mRNA的N4-乙酰胞苷（ac4C）修饰的关键酶。在这项研究中,我们研究了Nat10在心肌梗死（MI）后心脏纤维化中的作用及其相关机制。通过结扎左冠状动脉前降支在小鼠中诱发MI；用超声心动图评估心脏功能。我们发现，在MI后4周，在梗死区和边界区，Nat10的mRNA和蛋白表达水平均显着增加，MI后心肌成纤维细胞中Nat10的表达明显高于心肌细胞。Nat10的成纤维细胞特异性过表达促进小鼠MI后胶原沉积并诱导心脏收缩功能障碍。相反，Nat10的成纤维细胞特异性敲除可显着缓解MI后的心脏功能损害和细胞外基质重塑。然后，我们在用Nat10siRNA转染的心脏成纤维细胞中进行了ac4C-RNA结合蛋白免疫沉淀测序（RIP-seq），并揭示了血管动蛋白样1(Amotl1)，Hippo信号通路的上游调节因子,是Nat10的目标基因.我们证明了Nat10介导的ac4C修饰Amotl1增加了其在新生儿心脏成纤维细胞中的mRNA稳定性和翻译。从而增加Amotl1与yes相关蛋白1（Yap）的相互作用，并促进Yap易位到细胞核中。有趣的是，Amoll1或Yap的沉默，以及维替泊芬的治疗，一种选择性强效的Yap抑制剂,减弱了Nat10过表达诱导的心肌成纤维细胞增殖，并阻止了它们在体外分化为肌成纤维细胞。总之,本研究通过ac4C修饰Hippo/Yap信号通路中的上游激活剂,强调了Nat10作为MI损伤后心肌纤维化的关键调节因子。
