BACKGROUND Endoplasmic reticulum(ER)stress-related hepatocyte apoptosis is responsible for multiple hepatic diseases.Previous studies have revealed that endoplasmic reticulophagy(ER-phagy)promotes the selective cleara...BACKGROUND Endoplasmic reticulum(ER)stress-related hepatocyte apoptosis is responsible for multiple hepatic diseases.Previous studies have revealed that endoplasmic reticulophagy(ER-phagy)promotes the selective clearance of damaged ER fragments during ER stress,playing a crucial role in maintaining ER homeostasis and inhibiting apoptosis.Family with sequence similarity 134 member B(FAM134B)is a receptor involved in ER-phagy that can form a complex with calnexin(CNX)and microtubule-associated protein 1 light chain 3(LC3).The complex can mediate the selective isolation of ER fragments to attenuate hepatocyte apoptosis.However,the precise regulatory mechanisms remain unclear.AIM To elucidate the effect of FAM134B-mediated ER-phagy on ER stress-induced apoptosis in buffalo rat liver 3A(BRL-3A)rat hepatocytes and the potential regulatory mechanisms.METHODS ER stress-related hepatocyte apoptosis was induced using dithiothreitol(DTT).Proteins related to ER stress and autophagy were measured with western blotting.Protein complex interactions with FAM134B were isolated by co-immunoprecipitation.ER-phagy was evaluated in immunofluorescence experiments.Cell cycle distribution and apoptosis were measured by flow cytometry.Mitochondrial Ca^(2+) levels were evaluated by the co-localization of intracellular Ca^(2+)-tracker and Mitotracker.The small interfering RNA against FAM134B was used to knockdown FAM134B in BRL-3A cells.RESULTS ER stress-related and autophagy-related proteins in BRL-3A cells were elevated by both short and long-term DTT treatment.Furthermore,co-immunoprecipitation confirmed an interaction between FAM134B,CNX,FAM134B,and LC3 in BRL-3A cells.Immunofluorescence assays revealed that autolysosomes significantly decreased following short-term DTT treatment,but increased after long-term treatment.Mitochondrial Ca2+levels and apoptotic rates were dramatically elevated,and more cells were arrested in the G1 stage after short-term DTT treatment;however,these decreased 48 h later.Moreover,FAM134B downregulation accelerated mitochondrial apoptotic pathway activation and aggravated hepatocyte apoptosis under ER stress.CONCLUSION FAM134B-mediated ER-phagy attenuates hepatocyte apoptosis by suppressing the mitochondrial apoptotic pathway.Our findings provide new evidence highlighting the importance of FAM134Bmediated ER-phagy in attenuating hepatocyte apoptosis.展开更多
目的研究FAM134B在肝癌组织中的表达情况,探讨其表达差异与临床病理特征以及预后生存的关系。方法挖掘Oncomine、Human Protein Atlas、TCGA和Kaplan Meier-Plotter数据库,分析FAM134B在肝癌组织中的表达,并对表达量与临床病理特征以及...目的研究FAM134B在肝癌组织中的表达情况,探讨其表达差异与临床病理特征以及预后生存的关系。方法挖掘Oncomine、Human Protein Atlas、TCGA和Kaplan Meier-Plotter数据库,分析FAM134B在肝癌组织中的表达,并对表达量与临床病理特征以及预后生存的关系进行探讨。计数资料组间比较采用χ^2检验。FAM134B表达与肝癌预后的关系采用Kaplan-Meier模型分析。结果正常组织中,FAM134B在肾脏中表达量最高,肝脏居第9位,肿瘤组织中,其在肾癌组织表达最高,肝癌第11位。共147项有关FAM134B表达差异的研究结果差异具有统计学意义,各种癌症中其表达差异不一致。其在肝癌组织中表达量较正常肝组织中低。FAM134B蛋白定位于内质网,其表达量与肝癌患者发病年龄、肝硬化、AFP、人种、分化程度有相关性(P值均<0.05)。FAM134B表达量与肝癌患者总生存率有关[风险比(HR)=0.67,95%可信区间(95%CI):0.47~0.95,P=0.026],且对亚洲人种预后有显著影响(HR=0.40,95%CI:0.22~0.74,P=0.003),但对白色人种影响不显著(HR=0.65,95%CI:0.40~1.05,P=0.076)。结论FAM134B在不同癌症中表达不一致,在肝癌中低表达,蛋白定位于内质网,其低表达与肝癌部分恶性表型相关,且与患者总体生存率低有关。展开更多
基金Supported by National Natural Science Foundation of China,No.81560105Science and Technology Foundation of Guizhou Province,No.Qiankehe Jichu-ZK[2021]365,and No.Qiankehe Pingtai Rencai[2019]5801National Natural Science Foundation Cultivation Project of Guizhou Medical University,No.20NSP016。
文摘BACKGROUND Endoplasmic reticulum(ER)stress-related hepatocyte apoptosis is responsible for multiple hepatic diseases.Previous studies have revealed that endoplasmic reticulophagy(ER-phagy)promotes the selective clearance of damaged ER fragments during ER stress,playing a crucial role in maintaining ER homeostasis and inhibiting apoptosis.Family with sequence similarity 134 member B(FAM134B)is a receptor involved in ER-phagy that can form a complex with calnexin(CNX)and microtubule-associated protein 1 light chain 3(LC3).The complex can mediate the selective isolation of ER fragments to attenuate hepatocyte apoptosis.However,the precise regulatory mechanisms remain unclear.AIM To elucidate the effect of FAM134B-mediated ER-phagy on ER stress-induced apoptosis in buffalo rat liver 3A(BRL-3A)rat hepatocytes and the potential regulatory mechanisms.METHODS ER stress-related hepatocyte apoptosis was induced using dithiothreitol(DTT).Proteins related to ER stress and autophagy were measured with western blotting.Protein complex interactions with FAM134B were isolated by co-immunoprecipitation.ER-phagy was evaluated in immunofluorescence experiments.Cell cycle distribution and apoptosis were measured by flow cytometry.Mitochondrial Ca^(2+) levels were evaluated by the co-localization of intracellular Ca^(2+)-tracker and Mitotracker.The small interfering RNA against FAM134B was used to knockdown FAM134B in BRL-3A cells.RESULTS ER stress-related and autophagy-related proteins in BRL-3A cells were elevated by both short and long-term DTT treatment.Furthermore,co-immunoprecipitation confirmed an interaction between FAM134B,CNX,FAM134B,and LC3 in BRL-3A cells.Immunofluorescence assays revealed that autolysosomes significantly decreased following short-term DTT treatment,but increased after long-term treatment.Mitochondrial Ca2+levels and apoptotic rates were dramatically elevated,and more cells were arrested in the G1 stage after short-term DTT treatment;however,these decreased 48 h later.Moreover,FAM134B downregulation accelerated mitochondrial apoptotic pathway activation and aggravated hepatocyte apoptosis under ER stress.CONCLUSION FAM134B-mediated ER-phagy attenuates hepatocyte apoptosis by suppressing the mitochondrial apoptotic pathway.Our findings provide new evidence highlighting the importance of FAM134Bmediated ER-phagy in attenuating hepatocyte apoptosis.
文摘目的研究FAM134B在肝癌组织中的表达情况,探讨其表达差异与临床病理特征以及预后生存的关系。方法挖掘Oncomine、Human Protein Atlas、TCGA和Kaplan Meier-Plotter数据库,分析FAM134B在肝癌组织中的表达,并对表达量与临床病理特征以及预后生存的关系进行探讨。计数资料组间比较采用χ^2检验。FAM134B表达与肝癌预后的关系采用Kaplan-Meier模型分析。结果正常组织中,FAM134B在肾脏中表达量最高,肝脏居第9位,肿瘤组织中,其在肾癌组织表达最高,肝癌第11位。共147项有关FAM134B表达差异的研究结果差异具有统计学意义,各种癌症中其表达差异不一致。其在肝癌组织中表达量较正常肝组织中低。FAM134B蛋白定位于内质网,其表达量与肝癌患者发病年龄、肝硬化、AFP、人种、分化程度有相关性(P值均<0.05)。FAM134B表达量与肝癌患者总生存率有关[风险比(HR)=0.67,95%可信区间(95%CI):0.47~0.95,P=0.026],且对亚洲人种预后有显著影响(HR=0.40,95%CI:0.22~0.74,P=0.003),但对白色人种影响不显著(HR=0.65,95%CI:0.40~1.05,P=0.076)。结论FAM134B在不同癌症中表达不一致,在肝癌中低表达,蛋白定位于内质网,其低表达与肝癌部分恶性表型相关,且与患者总体生存率低有关。
