Human Phenome Institute, Center for Medical Research and Innovation, Shanghai Pudong Hospital, Fudan University Pudong Medical Centre, Zhangjiang Fudan International Innovation Center, Shanghai Key Laboratory of Bioactive Small Molecules, Fudan University, Shanghai, China.
Department of Cardiovascular Surgery, Shanghai General Hospital, Shanghai Jiao Tong University of Medicine, Shanghai, China.
Cell Death Dis. 2024 Sep 18;15(9):683. doi: 10.1038/s41419-024-07053-2.
Cardiomyocyte hypertrophy is a major outcome of pathological cardiac hypertrophy. The m6A demethylase ALKBH5 is reported to be associated with cardiovascular diseases, whereas the functional role of ALKBH5 in cardiomyocyte hypertrophy remains confused. We engineered Alkbh5 siRNA (siAlkbh5) and Alkbh5 overexpressing plasmid (Alkbh5 OE) to transfect cardiomyocytes. Subsequently, RNA immunoprecipitation (RIP)-qPCR, MeRIP-qPCR analysis and the dual-luciferase reporter assays were applied to elucidate the regulatory mechanism of ALKBH5 on cardiomyocyte hypertrophy. Our study identified ALKBH5 as a new contributor of cardiomyocyte hypertrophy. ALKBH5 showed upregulation in both phenylephrine (PE)-induced cardiomyocyte hypertrophic responses in vitro and transverse aortic constriction (TAC)/high fat diet (HFD)-induced pathological cardiac hypertrophy in vivo. Knockdown or overexpression of ALKBH5 regulated the occurrence of hypertrophic responses, including the increased cardiomyocyte surface areas and elevation of the hypertrophic marker levels, such as brain natriuretic peptide (BNP) and atrial natriuretic peptide (ANP). Mechanically, we indicated that ALKBH5 activated JAK2/STAT3 signaling pathway and mediated m6A demethylation on Stat3 mRNA, but not Jak2 mRNA, resulting in the phosphorylation and nuclear translocation of STAT3, which enhances the transcription of hypertrophic genes (e.g., Nppa) and ultimately leads to the emergence of cardiomyocytes hypertrophic growth. Our work highlights the functional role of ALKBH5 in regulating the onset of cardiomyocyte hypertrophy and provides a potential target for hypertrophic heart diseases prevention and treatment. ALKBH5 activated JAK2/STAT3 signaling pathway and mediated m6A demethylation on Stat3 mRNA, but not Jak2 mRNA, resulting in the phosphorylation and nuclear translocation of STAT3, which enhances the transcription of hypertrophic genes (e.g., Nppa) and ultimately leads to the emergence of cardiomyocytes hypertrophic growth.
心肌细胞肥大是病理性心肌肥大的主要结果。m6A 去甲基酶 ALKBH5 与心血管疾病有关，然而 ALKBH5 在心肌细胞肥大中的功能作用仍存在混淆。我们设计了 Alkbh5 siRNA（siAlkbh5）和 Alkbh5 过表达质粒（Alkbh5 OE）转染心肌细胞。随后，应用 RNA 免疫沉淀（RIP）-qPCR、MeRIP-qPCR 分析和双荧光素酶报告基因 assays 来阐明 ALKBH5 对心肌细胞肥大的调控机制。我们的研究确定了 ALKBH5 是心肌细胞肥大的一个新的贡献者。ALKBH5 在体外苯肾上腺素（PE）诱导的心肌细胞肥大反应和体内横主动脉缩窄（TAC）/高脂肪饮食（HFD）诱导的病理性心脏肥大中均上调。ALKBH5 的敲低或过表达调节了肥大反应的发生，包括增加心肌细胞表面积和升高肥大标志物水平，如脑钠肽（BNP）和心钠肽（ANP）。机制上，我们表明 ALKBH5 激活了 JAK2/STAT3 信号通路，并介导了 Stat3 mRNA 的 m6A 去甲基化，但 Jak2 mRNA 没有，导致 STAT3 的磷酸化和核转位，增强了肥大基因（如 Nppa）的转录，最终导致心肌细胞肥大生长的出现。我们的工作强调了 ALKBH5 在调节心肌细胞肥大发生中的功能作用，并为肥大性心脏病的预防和治疗提供了一个潜在的靶点。
