穿心莲内酯介导c-SKI抑制心肌成纤维细胞转分化和心肌纤维化

Andrgrapholide-mediated c-SKI inhibits myocardial fibroblast transdif⁃ferentiation and myocardial fibrosis

目的:探讨c-SKI(cellular Sloan-Kettering Institute)蛋白表达变化对穿心莲内酯(andrgrapholide,Andr)治疗小鼠心肌纤维化的影响。方法:将18只C57雄性小鼠随机分为control组、模型组[异丙肾上腺素(isoprenaline,ISO)组]和ISO+Andr组,每组6只。ISO组和ISO+Andr组小鼠皮下注射ISO,control组注射生理盐水;ISO+Andr组小鼠给予Andr灌胃,ISO组和control组给予等体积生理盐水灌胃。给药8周,取心脏组织进行HE和Masson染色检测病理特征;免疫组化或Western blot实验检测c-SKI和细胞外基质(extracellular matrix,ECM)相关蛋白水平;qPCR检测c-SKI mRNA水平。用不同浓度Andr干预人心脏成纤维细胞(human cardiac fibroblasts,HCFBs)48 h,CCK-8实验检测细胞活力,Western blot实验检测c-SKI和ECM相关蛋白水平。用Andr最低有效剂量处理转分化细胞模型,显微镜观察细胞形态,Western blot实验检测c-SKI和ECM相关蛋白水平,qPCR检测c-SKI mRNA水平。敲减c-SKI和Andr联合处理转化生长因子β1(transforming growth factor-β1,TGF-β1)诱导的HCFBs,CCK-8实验检测细胞增殖活力,Western blot实验检测c-SKI和ECM相关蛋白水平。结果:与ISO组相比,Andr干预后小鼠心肌纤维排列整齐,心肌细胞形态基本正常,细胞膜完整,胶原容积分数显著减少(P<0.01),c-SKI的mRNA和蛋白水平显著上调(P<0.05或P<0.01),纤连蛋白1(fibronectin 1,FN1)、α-平滑肌肌动蛋白(α-smooth muscle actin,α-SMA)、波形蛋白(vimentin)和I型胶原(collagen type I,Col I)蛋白水平显著下调(P<0.01)。HCFBs经50μmol/L Andr处理48 h,细胞活力显著降低(P<0.01),FN1、α-SMA、vimentin和Col I蛋白水平显著下调(P<0.01),c-SKI表达显著上调(P<0.01)。与PBS组相比,TGF-β1组细胞数量增多,胞核固缩,细胞形态改变,细胞中FN1、α-SMA、vimentin和Col I蛋白表达显著上调(P<0.01),c-SKI表达显著下调(P<0.01);Andr干预逆转了TGF-β1对HCFBs的诱导作用。敲减c-SKI和Andr联合处理显著下调HCFBs中c-SKI表达(P<0.01),显著上调FN1、α-SMA、vimentin和Col I蛋白表达水平(P<0.05),显著增强细胞活力(P<0.05)。结论:Andr可能通过调控c-SKI表达影响TGF-β1信号通路,抑制心肌成纤维细胞增殖和ECM沉积,从而抑制心肌纤维化。

AIM:To investigate the effect of cellular Sloan-Kettering Institute(c-SKI)protein expression on myocardial fibrosis in mice treated with andrgrapholide(Andr).METHODS:Male C57 mice were randomly divided into control group,model group[isoprenaline(ISO)group]and ISO+Andr group,with 6 mice per group.The mice in ISO and ISO+Andr groups were subcutaneously injected with ISO,while those in control group were injected with normal saline.The mice in ISO+Andr group was intragastrically given Andr,while those in ISO and control groups were given normal saline.The histopathological characteristics of the heart tissue were detected by HE and Masson staining after 8 weeks of administration.The expression levels of c-SKI and extracellular matrix(ECM)-related proteins were detected by immunohistochemistry or Western blot.The c-SKI mRNA level was detected by qPCR.Human cardiac fibroblasts(HCFBs)were treated with different concentrations of Andr for 48 h.The cell viability was detected by CCK-8 assay,and the c-SKI and ECM-related protein levels were detected by Western blot.The transdifferentiated cell model was treated with the lowest effective dose of Andr.The cell morphology was observed under a microscope,the levels of c-SKI and ECM-related pro-teins were assessed by Western blot,and the c-SKI mRNA level was detected by qPCR.The transforming growth factor-β1(TGF-β1)-treated HCFBs were treated with the combination of c-SKI knockdown and Andr.The cell viability was detected by CCK-8 assay,and the levels of c-SKI and ECM-related proteins were detected by Western blot.RESULTS:After the intervention of Andr,the myocardial fibers in mice were neatly arranged,the morphology of myocardial cells was basically normal,the cell membrane was intact,and the collagen volume fraction was significantly reduced(P<0.01).The mRNA and protein levels of c-SKI were significantly up-regulated(P<0.05 or P<0.01),and the protein levels of fibronectin 1(FN1),α-smooth muscle actin(α-SMA),vimentin and collagen type I(Col I)were significantly down-regulated(P<0.01).After 50μmol/L Andr treatment for 48 h,the viability of HCFBs was significantly decreased(P<0.01),the pro-tein levels of Col I,α-SMA,vimentin and FN1 were significantly down-regulated(P<0.01),and c-SKI expression was significantly up-regulated(P<0.01).Compared with PBS group,the number of the HCFBs in TGF-β1 group increased with flattened and irregular morphological change,and the FN1,α-SMA,Col I and vimentin levels were significantly in-creased(P<0.01),while c-SKI expression was significantly decreased(P<0.01).After Andr intervention,the induction effect of TGF-β1 on HCFBs was reversed.Knockdown of c-SKI combined with Andr treatment in HCFBs significantly down-regulated c-SKI expression(P<0.01),significantly up-regulated FN1,α-SMA,vimentin and Col I levels(P<0.05),and significantly increased the cell viability.CONCLUSION:Andrgrapholide may affect the TGF-β1 signaling pathway by regulating c-SKI expression,and inhibit the proliferation of myocardial fibroblasts and ECM deposition,thus inhibiting myocardial fibrosis.