背景与目的:肿瘤的发生、发展过程中会发生代谢重编程,1-酰基甘油-3-磷酸O-酰基转移酶(1-acylglycerol-3-phosphate O-acyltransferase,AGPAT)作为三酰甘油(triacylglycerol,TAG)从头合成的关键酶,与肿瘤的进展密切相关。但目前作为亚...背景与目的:肿瘤的发生、发展过程中会发生代谢重编程,1-酰基甘油-3-磷酸O-酰基转移酶(1-acylglycerol-3-phosphate O-acyltransferase,AGPAT)作为三酰甘油(triacylglycerol,TAG)从头合成的关键酶,与肿瘤的进展密切相关。但目前作为亚型之一的AGPAT5在癌症中的研究还十分有限,本研究深入剖析AGPAT5在肝癌发生、发展中发挥的作用及潜在的分子机制,旨在为肝癌诊断和治疗策略提供新思路。方法:利用慢病毒感染将多种肝癌细胞系中的AGPAT5敲减,并通过锥虫蓝计数、划痕、transwell及平板克隆等实验在体外检测AGPAT5对肝癌细胞增殖、迁移及抗失巢凋亡能力的影响。通过回复野生型或酶活性缺失型的AGPAT5,探究其作为代谢酶是否发挥经典代谢作用调控肝癌细胞迁移。构建BALB/c裸鼠尾静脉注射移植瘤模型,从体内层面验证体外的细胞表型。采用免疫沉淀质谱联用(immunoprecipitation mass spectrum,IP-MS)鉴定出与AGPAT5相互作用的蛋白,并进行免疫共沉淀(co-immunoprecipitation,coIP)验证。蛋白质翻译后通过修饰鉴定分析AGPAT5潜在的修饰位点,通过体外实验探究点突变前后对肝癌细胞迁移的影响。通过coIP探究该位点突变前后AGPAT5与相互作用蛋白结合的情况。通过敲低相互作用蛋白确定其在细胞表型中的作用。通过回复实验验证AGPAT5是否通过相互作用蛋白发挥作用。检测野生型肝癌细胞系中的AGPAT5和相互作用蛋白的表达水平,检验两者之间是否具有相关性。结果:肝癌细胞敲减AGPAT5后会更加耐受无血清饥饿,并促进细胞迁移,但不会影响细胞增殖和失巢凋亡。而酶活性缺失并不影响AGPAT5对肝癌细胞迁移的抑制。敲减AGPAT5可促进肝癌细胞在裸鼠体内的肺转移和肝转移。AGPAT5可以与原纤维蛋白(fibrillarin,FBL)相互作用,并在无血清饥饿刺激下加强两者的结合。遏制FBL的表达会抑制肝癌细胞迁移,且效果与过表达AGPAT5相似。抑制FBL的表达可削弱敲低AGPAT5对肝癌细胞迁移的促进作用。在已检测的肝癌细胞系中,AGPAT5和FBL在蛋白水平上并不存在相关性。K201位点突变使AGPAT5对肝癌细胞迁移的抑制作用减弱,并使AGPAT5与FBL的结合减弱。结论:敲低AGPAT5能够显著提高肝癌细胞迁移能力。AGPAT5可以与FBL相互作用,在无血清饥饿刺激下,AGPAT5或通过K201位点的乙酰化加强与FBL的结合,从而更有效地遏制FBL,进而抑制肝癌细胞迁移。但这种抑制作用并非来自AGPAT5的代谢酶活性,而是由非代谢作用所驱动。展开更多
Nonalcoholic fatty liver disease (NAFLD) has, although it is a very common disorder, only relatively recently gained broader interest among physicians and scientists. Fatty liver has been documented in up to 10 to 15 ...Nonalcoholic fatty liver disease (NAFLD) has, although it is a very common disorder, only relatively recently gained broader interest among physicians and scientists. Fatty liver has been documented in up to 10 to 15 percent of normal individuals and 70 to 80 percent of obese individuals. Although the pathophysiology of NAFLD is still subject to intensive research, several players and mechanisms have been suggested based on the substantial evidence. Excessive hepatocyte triglyceride accumulation resulting from insulin resistance is the first step in the proposed 'two hit' model of the pathogenesis of NAFLD. Oxidative stress resulting from mitochondrial fatty acids oxidation, NF-κB-dependent inflammatory cytokine expression and adipocytokines are all considered to be the potential factors causing second hits which lead to hepatocyte injury, inflammation and fibrosis. Although it was initially believed that NAFLD is a completely benign disorder, histologic follow-up studies have showed that fibrosis progression occurs in about a third of patients. A small number of patients with NAFLD eventually ends up with end-stage liver disease and even hepatocellular carcinoma. Although liver biopsy is currently the only way to confirm the NAFLD diagnosis and distinguish between fatty liver alone and NASH, no guidelines or firm recommendations can still be made as for when and in whom it is necessary. Increased physical activity, gradual weight reduction and in selected cases bariatric surgery remain the mainstay of NAFLD therapy. Studies with pharmacologic agents are showing promising results, but available data are still insufficient to make specific recommendations; their use therefore remains highly individual.展开更多
文摘背景与目的:肿瘤的发生、发展过程中会发生代谢重编程,1-酰基甘油-3-磷酸O-酰基转移酶(1-acylglycerol-3-phosphate O-acyltransferase,AGPAT)作为三酰甘油(triacylglycerol,TAG)从头合成的关键酶,与肿瘤的进展密切相关。但目前作为亚型之一的AGPAT5在癌症中的研究还十分有限,本研究深入剖析AGPAT5在肝癌发生、发展中发挥的作用及潜在的分子机制,旨在为肝癌诊断和治疗策略提供新思路。方法:利用慢病毒感染将多种肝癌细胞系中的AGPAT5敲减,并通过锥虫蓝计数、划痕、transwell及平板克隆等实验在体外检测AGPAT5对肝癌细胞增殖、迁移及抗失巢凋亡能力的影响。通过回复野生型或酶活性缺失型的AGPAT5,探究其作为代谢酶是否发挥经典代谢作用调控肝癌细胞迁移。构建BALB/c裸鼠尾静脉注射移植瘤模型,从体内层面验证体外的细胞表型。采用免疫沉淀质谱联用(immunoprecipitation mass spectrum,IP-MS)鉴定出与AGPAT5相互作用的蛋白,并进行免疫共沉淀(co-immunoprecipitation,coIP)验证。蛋白质翻译后通过修饰鉴定分析AGPAT5潜在的修饰位点,通过体外实验探究点突变前后对肝癌细胞迁移的影响。通过coIP探究该位点突变前后AGPAT5与相互作用蛋白结合的情况。通过敲低相互作用蛋白确定其在细胞表型中的作用。通过回复实验验证AGPAT5是否通过相互作用蛋白发挥作用。检测野生型肝癌细胞系中的AGPAT5和相互作用蛋白的表达水平,检验两者之间是否具有相关性。结果:肝癌细胞敲减AGPAT5后会更加耐受无血清饥饿,并促进细胞迁移,但不会影响细胞增殖和失巢凋亡。而酶活性缺失并不影响AGPAT5对肝癌细胞迁移的抑制。敲减AGPAT5可促进肝癌细胞在裸鼠体内的肺转移和肝转移。AGPAT5可以与原纤维蛋白(fibrillarin,FBL)相互作用,并在无血清饥饿刺激下加强两者的结合。遏制FBL的表达会抑制肝癌细胞迁移,且效果与过表达AGPAT5相似。抑制FBL的表达可削弱敲低AGPAT5对肝癌细胞迁移的促进作用。在已检测的肝癌细胞系中,AGPAT5和FBL在蛋白水平上并不存在相关性。K201位点突变使AGPAT5对肝癌细胞迁移的抑制作用减弱,并使AGPAT5与FBL的结合减弱。结论:敲低AGPAT5能够显著提高肝癌细胞迁移能力。AGPAT5可以与FBL相互作用,在无血清饥饿刺激下,AGPAT5或通过K201位点的乙酰化加强与FBL的结合,从而更有效地遏制FBL,进而抑制肝癌细胞迁移。但这种抑制作用并非来自AGPAT5的代谢酶活性,而是由非代谢作用所驱动。
文摘Nonalcoholic fatty liver disease (NAFLD) has, although it is a very common disorder, only relatively recently gained broader interest among physicians and scientists. Fatty liver has been documented in up to 10 to 15 percent of normal individuals and 70 to 80 percent of obese individuals. Although the pathophysiology of NAFLD is still subject to intensive research, several players and mechanisms have been suggested based on the substantial evidence. Excessive hepatocyte triglyceride accumulation resulting from insulin resistance is the first step in the proposed 'two hit' model of the pathogenesis of NAFLD. Oxidative stress resulting from mitochondrial fatty acids oxidation, NF-κB-dependent inflammatory cytokine expression and adipocytokines are all considered to be the potential factors causing second hits which lead to hepatocyte injury, inflammation and fibrosis. Although it was initially believed that NAFLD is a completely benign disorder, histologic follow-up studies have showed that fibrosis progression occurs in about a third of patients. A small number of patients with NAFLD eventually ends up with end-stage liver disease and even hepatocellular carcinoma. Although liver biopsy is currently the only way to confirm the NAFLD diagnosis and distinguish between fatty liver alone and NASH, no guidelines or firm recommendations can still be made as for when and in whom it is necessary. Increased physical activity, gradual weight reduction and in selected cases bariatric surgery remain the mainstay of NAFLD therapy. Studies with pharmacologic agents are showing promising results, but available data are still insufficient to make specific recommendations; their use therefore remains highly individual.
