RBM20和MURC双基因杂合变异对心肌细胞结构和生物学特性的影响

Effect of RBM20 and MURC digenic heterozygosity variation on the structure and biological characteristics of myocardial cells

目的探讨RNA结合基元蛋白20(RBM20)和肌肉相关卷曲螺旋蛋白(MURC)双基因杂合变异对人心肌细胞AC16(成人左心室心肌细胞系)结构和生物学特性的影响。方法构建对照组、空载组、野生组、MURC或RBM20单基因突变组、RBM20和MURC双基因突变组的心肌细胞AC16;采用Western blotting、免疫荧光染色和实时荧光定量PCR观察心肌细胞中RBM20和MURC定位、细胞表面积、骨架排列、骨架相关蛋白、细胞极性、细胞内钙浓度;采用流式细胞术检测心肌细胞凋亡;采用Ki-67染色检测心肌细胞增殖;采用划痕实验检测心肌细胞迁移。结果与RBM20或MURC单基因突变相比,RBM20和MURC双基因突变对心肌细胞结构和生物学特性影响更显著,表现为细胞表面积增大,细胞肥大相关基因肌球蛋白重链7和α肌动蛋白基因m RNA表达升高,骨架排列紊乱度升高,骨架蛋白β-tubulin和Vinculin荧光强度降低(均P<0.01);极性蛋白Part6荧光强度升高(P<0.05);心肌细胞凋亡率升高,增殖活性下降,迁移率增高,细胞内钙离子浓度升高(均P<0.01)。结论RBM20和MURC双基因杂合变异使心肌细胞结构及生物学特性发生改变,表现为细胞表面积增大,骨架排列紊乱,极性改变,凋亡率和迁移率升高,增殖活性和钙处理能力降低。

Objective To investigate the impact of variations in RNA-binding motif protein 20(RBM20)and muscle-restricted coiledcoil(MURC)digenic heterozygosity variation on the structural and biological characteristics of human cardiomyocyte AC16(an adult left ventricular myocardial cell line).Methods Cardiomyocyte AC16 cell lines were constructed with control,negative scramble,wildtype,MURC single-gene mutant,RBM20 single-gene mutant,and RBM20 and MURC digenic mutant groups.The localization of RBM20 and MURC in cardiomyocytes,cell area,cytoskeletal arrangement,cytoskeleton-related proteins,cell polarity,and intracellular calcium concentration were observed using Western blotting,immunofluorescence staining,and reverse transcription polymerase chain reaction.Myocardial apoptosis was detected using flow cytometry.Ki-67 staining and wound healing assays were performed to detect cardiomyocyte proliferation and migration,respectively.Results Digenic mutations had a more pronounced impact than single-gene mutations in RBM20 or MURC on the structural and biological characteristics of cardiomyocytes,manifested by increased cell area,upregulated mRNA expression of hypertrophy-related genes,such as myosin heavy chain 7 and alpha-actin,increased cytoskeleton disturbance,decreased fluorescence intensity of cytoskeletal proteinsβ-tubulin and Vinculin(all P<0.01);increased fluorescence intensity of the polarity protein Part 6(P<0.05);and significantly elevated cardiomyocyte apoptosis rate,decreased proliferative activity,and elevated migration rate and intracellular calcium ion concentration(all P<0.01).Conclusion The digenic heterozygous variation in RBM20 and MURC may induce changes in the morphological structure and biological characteristics of myocardial cells,including increased cell area,cytoskeleton disturbance,cell polarity,increased apoptosis rate and mobility,decreased cell proliferation activity,and calcium processing ability.