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.

心肌细胞肥大是病理性心脏肥大的主要结果。据报道，m6A 去甲基酶 ALKBH5 与心血管疾病相关，但 ALKBH5 在心肌细胞肥大中的功能作用仍不清楚。我们设计了Alkbh5 siRNA (si Alkbh5 ) 和Alkbh5过表达质粒 ( Alkbh5 OE) 来转染心肌细胞。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测定来阐明ALKBH5对心肌细胞肥大的调节机制。我们的研究确定 ALKBH5 是心肌细胞肥大的新贡献者。 ALKBH5 在体外去氧肾上腺素 (PE) 诱导的心肌细胞肥大反应和体内横主动脉缩窄 (TAC)/高脂饮食 (HFD) 诱导的病理性心脏肥大中均表现出上调。 ALKBH5 的敲低或过度表达可调节肥厚反应的发生，包括心肌细胞表面积增加和肥厚标志物水平升高，例如脑钠尿肽 (BNP) 和心房钠尿肽 (ANP)。从机制上讲，我们表明ALKBH5激活JAK2/STAT3信号通路并介导Stat3 mRNA而非Jak2 mRNA上的m6A去甲基化，导致STAT3磷酸化和核转位，从而增强肥大基因（例如Nppa ）的转录并最终导致心肌细胞肥大性生长的出现。我们的工作强调了 ALKBH5 在调节心肌细胞肥大发作中的功能作用，并为肥厚性心脏病的预防和治疗提供了潜在靶点。