过表达甲基转移酶3发挥促进心肌纤维化的作用研究

Study on overexpression of methyltransferase-like 3 promoting myocardial fibrosis

目的研究过表达甲基转移酶3(METTL3)对小鼠心肌纤维化的影响。方法检测心衰患者和健康器官捐献者心肌METTL3表达水平。建立主动脉弓缩窄(TAC)手术诱导的C57BL/6小鼠心肌纤维化模型,检测TAC组与假手术组小鼠心肌METTL3表达水平。建立血管紧张素Ⅱ(AngⅡ)诱导小鼠心肌成纤维细胞(CF)的心肌纤维化细胞模型,并检测小鼠CF中METTL3的表达水平。利用腺病毒介导小鼠CF高表达METTL3,检测纤维化相关基因Ⅰ型胶原α1链(COL1α1)、Ⅲ型胶原α1链(COL3α1)和肌动蛋白α2(ACTα2)的表达。通过流式细胞术、EdU和Transwell细胞迁移实验检测小鼠CF的增殖和迁移能力。在整体水平鉴定心肌特异过表达METTL3对TAC小鼠心功能和心肌纤维化的影响。结果心衰患者心肌中METTL3的表达显著升高(P<0.05)。TAC小鼠心肌与AngⅡ诱导的小鼠CF中METTL3的表达显著增加(P<0.05)。过表达METTL3可显著提高小鼠CF的增殖、迁移能力和纤维化相关基因的表达。与假手术组小鼠相比,TAC诱导心肌特异过表达METTL3小鼠心肌中纤维化相关基因表达显著增加,心肌纤维化和心功能损伤显著加重。结论过表达METTL3具有促进心肌纤维化的作用。

Aim To investigate the effect of overexpression of methyltransferase-like 3(METTL3)on myocardial fibrosis.Methods METTL3 protein expression was detected in the myocardium of patients with heart failure(HF)and the healthy donors by Western blot assay.A C57BL/6 mouse model of transverse aortic constriction(TAC)surgery-induced myocardial fibrosis was established,and METTL3 protein expression was detected in the myocardium of TAC mice and sham mice.A cell model of angiotensinⅡ(AngⅡ)-induced myocardial fibrosis in mouse cardiac fibroblasts(CF)was established and used to detect METTL3 expression by Western blot assay.Expression of fibrosis-related genes,including collagen typeⅠα1(COL1α1),collagen typeⅢα1(COL3α1)and actinα2(ACTα2),was detected in mouse CF with adenovirus-mediated overexpression of METTL3.Flow cytometry,EdU and Transwell migration assay were used to detect proliferation and migration activity of mouse CF,respectively.Effects of cardiac specific expression of METTL3 on cardiac function and fibrosis were explored in mice subjected to TAC surgery.Results Protein expression of METTL3 was significantly increased in the myocardium of HF patients(P<0.05).Consistently,significant up-regulation of METTL3 was observed in the myocardium of TAC mice and AngⅡ-treated mouse CF(P<0.05,respectively).Overexpression of METTL3 could markedly enhance mouse CF proliferation and migration activities,as well as expression of fibrosis-related genes in mouse CF.Compared with mice in the sham group,significant increase of fibrosis-related gene expression,cardiac fibrosis and cardiac function injury were observed in TAC-induced mice with cardiac specific overexpression of METTL3.Conclusion Overexpression of METTL3 promotes cardiac fibrosis in mice.