卡尔帕因
肌球蛋白轻链激酶
压力过载
肌肉肥大
肌球蛋白
内科学
内分泌学
生物
细胞生物学
医学
生物化学
心肌肥大
酶
作者
Shun Wang,Haixiong Wang,Xiaoling Su,Beilei Liu,Le Wang,Hui Yan,Shuai Mao,He Huang,Congxin Huang,Mian Cheng,Gang Wu
标识
DOI:10.1016/j.biopha.2020.110438
摘要
β-adrenergic activation is able to exacerbate cardiac hypertrophy. Myosin light chain kinase (MLCK) and its phosphorylated substrate, phospho-myosin light chain 2 (p-MLC2), play vital roles in regulating cardiac hypertrophy. However, it is not yet clear whether there is a relationship between β-adrenergic activation and MLCK in the progression of cardiac hypertrophy. Therefore, we explored this relationship and the underlying mechanisms in this work. Cardiac hypertrophy and cardiomyocyte hypertrophy were induced by pressure overload and isoproterenol (ISO) stimulation, respectively. Echocardiography, histological analysis, immunofluorescence and qRT-PCR were used to confirm the successful establishment of the models. A β-blocker (metoprolol) and a calpain inhibitor (calpeptin) were administered to inhibit β-adrenergic activity in rats and calpain in cardiomyocytes, respectively. The protein expression levels of MLCK, myosin light chain 2 (MLC2), p-MLC2, myosin phosphatase 2 (MYPT2), calmodulin (CaM) and calpain were measured using western blotting. A cleavage assay was performed to assess the degradation of recombinant human MLCK by recombinant human calpain. The β-blocker alleviated cardiac hypertrophy and dysfunction, increased MLCK and MLC2 phosphorylation and decreased calpain expression in pressure overload-induced cardiac hypertrophy. Additionally, the calpain inhibitor calpeptin attenuated cardiomyocyte hypertrophy, upregulated MLCK and p-MLC2 and reduced MLCK degradation in ISO-induced cardiomyocyte hypertrophy. Recombinant human calpain degraded recombinant human MLCK in vitro in concentration- and time-dependent manners, and this degradation was inhibited by the calpain inhibitor calpeptin. Our study suggested that β-adrenergic activation may promote the degradation of MLCK through calpain in pressure overload-induced cardiac hypertrophy.
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