肝再生增强因子通过增加自噬水平促进CCl4诱导的急性肝损伤中HL-7702细胞的增殖

Augmenter of liver regeneration promotes the proliferation of HL-7702 cells in carbon tetracldoride-induced acute liver injury via increasing autophagy

目的研究肝再生增强因子（ALR）保护急性肝损伤的作用及其机制。方法HL-7702细胞分为正常对照组、CCl4急性肝损伤组、ALR＋CCl4干预组、3-甲基腺嘌呤（3-MA）＋CCl4干预组以及ALR＋3-MA＋CCl4干预组，CCl4处理前8h对ALR＋CCl4和ALR＋3-MA＋CCl4干预组转染ALR质粒，对除正常对照组外其余四组给予CCl4处理，30min后对3-MA＋CCl4和ALR＋3-MA＋CCl4干预组给予3-MA处理，CCl4处理24h后收集细胞。收集HL-7702细胞和培养上清液，检测丙氨酸氨基转移酶（ALT）、天冬氨酸氨基转移酶（AST）水平；Westernblot检测细胞中ALR、细胞周期蛋白D、细胞周期蛋白E、增殖细胞核抗原（PCNA）、自噬相关基因7（Atg7）和自噬基因LC3、p62、Beclin-1水平；实时定量PCR检测ALRmRNA水平。多组样本均数的两两比较采用One-wayANOVA分析。结果ALR＋CCl4干预组与急性肝损伤组相比，ALR蛋白以及mRNA表达水平显著升高（P值均〈0．05）；CCl4急性肝损伤组与正常对照组相比，ALR蛋白以及mRNA表达水平同样显著升高（P值均〈0．05）。ALR＋CCl4干预组与CCl4急性肝损伤组相比，细胞上清液中ALT（0．73±0．17与1．43±0．38，P值均〈0．05）、AST（19．85±1．83与56．73±6．25，P值均〈0．05）水平显著降低（单位均为IU／L）；肝细胞中再生相关细胞周期蛋白D、细胞周期蛋白E、PCNA表达水平以及自噬相关LC3、Atg7、Beclin-1表达水平显著增高，P62表达水平显著降低，提示ALR可以保护急性肝损伤，促进肝细胞的再生，增强肝细胞的自噬水平。ALR＋3-MA＋CCl4干预组再生相关蛋白的表达水平相较于ALR＋CCl4干预组明显降低，与3-MA＋CCl4干预组相比无明显差异，提示抑制自噬后，肝细胞再生水平明显下降，ALR促进肝再生的作用也明显减弱。结论ALR可以促进肝脏实质细胞再生，这种再生是通过调节自噬完成的。

Objective To investigate the protective effect of augmenter of liver regeneration （ALR） against acute liver injury and related mechanisms. Methods HL-7702 cells were divided into normal control group, carbon tetrachloride （CCl4）-induced acute liver injury group, ALR＋CCl4 intervention group, 3-methyladenine （3-MA）＋CCl4 intervention group, and ALR＋3-MA＋CCl4 intervention group. The ALR＋CCl4 and ALR＋3-MA＋CCl4 intervention groups were transfected with ALR plasmids at 8 hours before CCl4 treatment. All groups except the normal control group were treated with CCl4, and 30 minutes later, the 3-MA＋CCl4 and ALR＋3-MA＋CCl4 intervention groups were treated with 3-MA. The cells were collected at 24 hours after CCl4 treatment. The HL-7702 cells and supematant were collected to measure the levels of alanine aminotransferase （ALT） and aspartate aminotransferase （AST） （IU/L）. Western blot was used to measure the levels ofALR, cyclin D, cyclin E, proliferating cell nuclear antigen （PCNA）, autophagy-related gene 7 （Atg7）, and autophagy genes LC3, p62, and Beclin-1. Quantitative real-time PCR was used to measure the mRNA expression ofALR. A one- way analysis of variance was used for comparison of means between any two groups. Results The ALR＋CCl4 intervention group had significant increases in the protein and mRNA expression of ALR compared with the acute liver injury group （both P 〈 0.05）. The CCl4-induced acute liver injury group had significant increases in the protein and mRNA expression of ALR compared with the normal control group （both P 〈 0.05）. Compared with the CCl4-induced acute liver injury group, the ALR＋CCl4 intervention group had significant reductions in ALT （0.73±0.17 IU/L vs 1.43±0.38 IU/L, P 〈 0.05） and AST （19.85±1.83 IU/L vs 56.73±6.25 IU/L, P 〈 0.05） in supematant, significantly increased expression of cyclin D, cyclin E, PCNA, LC3, Atg7, and Beclin-1 in hepatocytes, and significantly reduced expression of p62, which suggested that ALR protected the liver against acute liver injury, promoted the regeneration of hepatocytes, and enhanced the autophagy of hepatocytes. The ALR＋3-MA＋CCl4 intervention group had a significant reduction in the expression of regeneration-associated proteins compared with the ALR＋CCl4 intervention group, while there was no significant difference between the ALR＋3-MA＋CCl4 intervention group and 3-MA＋CCl4 intervention group, which suggested that after the inhibition of autophagy, there were significant reductions in the regeneration of hepatocytes and liver regeneration promoted by ALR. Conclusion ALR can promote the regeneration ofhepatocytes in liver parenchyma, which is achieved by the regulation of autophagy.