摘要
肝细胞含有丰富的内质网和线粒体,两者以相互作用的方式调控肝细胞生命活动,但相互作用的机制尚未完全阐明。内质网中存在一套高度保守的蛋白质质量控制系统,即内质网相关降解(endoplasmic reticulum associated degradation,ERAD)。最新研究发现,ERAD可通过线粒体相关膜性结构(mitochondria associated membranes,MAMs)调控脂肪细胞线粒体功能,但在肝细胞中,关于ERAD与线粒体之间的相互作用及机制目前仍不明确。本研究选用HepG2作为细胞模型,通过化学药物诱导和基因敲除2种方法构建ERAD功能障碍肝细胞模型。采用荧光标记、流式分析和免疫印迹等技术手段,探究ERAD在肝细胞线粒体中的作用。结果发现,ERAD功能障碍会降低HepG2肝细胞线粒体膜电位和ATP水平(P<0.01);而且,ERAD功能障碍还会破坏HepG2细胞内质网与线粒体Ca^(2+)稳态,当减少内质网Ca^(2+)释放时,可改善线粒体能量代谢功能(P<0.05)。这些发现在ERAD功能障碍小鼠原代肝细胞中得到进一步验证。上述结果表明,ERAD在肝细胞内质网与线粒体相互作用中具有重要的调控作用,增强ERAD功能可能提升肝细胞线粒体活性,为线粒体功能障碍相关疾病提供新的研究思路。
In hepatocytes,the endoplasmic reticulum and mitochondria work together in a reciprocal manner to regulate the physiological functions of the cells.Nevertheless,its precise mechanism remains unknown.Endoplasmic reticulum-associated degradation(ERAD)is a key process for maintaining protein quality in the endoplasmic reticulum.Recent studies have found that ERAD can regulate the adipocyte mitochondrial function through mitochondria associated membranes(MAMs).However,it is still unknown how exactly ERAD and mitochondria interact with one another in hepatocytes.In this study,chemical induction and gene deletion were used to induce ERAD deficiency in HepG2 cells.To investigate the effect of ERAD on mitochondrial function in hepatocytes,we employed fluorescent labelling,flow analysis,immunoblotting and other methods.The results demonstrated that ERAD dysfunction resulted in a reduction in the mitochondrial membrane potential and ATP levels in HepG2 cells(P<0.01).Furthermore,ERAD dysfunction also disrupted the endoplasmic reticulum and mitochondrial Ca^(2+)homeostasis in HepG2 cells,and improved mitochondrial energy metabolism function when endoplasmic reticulum Ca^(2+)release was reduced(P<0.05).These findings were further validated in ERAD dysfunctional primary hepatocytes,which had been induced by pharmacological agents.The data above indicate that ERAD plays a key regulatory role in endoplasmic reticulum-mitochondrial interactions in hepatocytes.Enhanced ERAD function may boost mitochondrial activity in hepatocytes.This study offers fresh perspectives on disorders linked to mitochondrial malfunction.
作者
蒋贝尔
张峰
白永凤
吴麒
胡亚兵
JIANG Bei-Er;ZHANG Feng;BAI Yong-Feng;WU Qi;HU Ya-Bing(Department of Pulmonary and Critical Care Medicine,The Quzhou Affiliated Hospital of Wenzhou Medical University,Quzhou 324000,Zhejiang,China;Precision Medicine Center,The Quzhou Affiliated Hospital of Wenzhou Medical University,Quzhou 324000,Zhejiang,China;Department of Physiology,School of Basic medical Sciences,Xuzhou Medical University,Xuzhou 221004,Jiangsu,China)
出处
《中国生物化学与分子生物学报》
CAS
CSCD
北大核心
2024年第12期1723-1731,共9页
Chinese Journal of Biochemistry and Molecular Biology
基金
国家自然科学基金(No.8210033791)
衢州市高层次医疗卫生人才培养工程(No.KYQD2022-05)资助。
关键词
肝细胞
细胞器相互作用
内质网相关降解
线粒体功能
钙离子
hepatocyte
organelle interactions
endoplasmic reticulum associated degradation(ERAD)
mitochondrial function
calcium ion(Ca^(2+))