Li Rong, Yang Longbao, Li Shunle, Chen Shuo, Ren Yifan, Shen Lin, Dong Lei, Chen Xi, Li Junhui, Xu Meng
Department of Anesthesiology, The Second Affiliated Hospital of Xi'an JiaoTong University, Xi'an, People's Republic of China.
Department of Gastroenterology, The Second Affiliated Hospital of Xi'an JiaoTong University, Xi'an, People's Republic of China.
J Biochem Mol Toxicol. 2024 Jan;38(1):e23630. doi: 10.1002/jbt.23630.
Hepatic ischemia-reperfusion (IR) injury is a complex systemic process causing a series clinical problem. C/EBPα is a key transcription factor for hepatocyte function, but its role and mechanism in regulating hepatic IR injury are largely unknown. Occluding portal vein and hepatic artery was used to establish a mouse model of hepatic IR injury. C/EBPα expression was decreased in IR-injured liver compared with the sham, accompanied by increased contents of serum alanine transaminase (ALT), aspartate transaminase (AST), high mobility group box-1, and proportion of hepatic cells. Oxygen and glucose deprivation/recovery (OGD/R) was used to establish a cellular hepatic IR model in WRL-68 hepatocytes in vitro, and C/EBPα was overexpressed in the hepatocytes to evaluate its effect on hepatic IR injury. OGD/R promoted oxidative stress, cell apoptosis and endoplasmic reticulum (ER) stress in hepatocytes, which was reversed by C/EBPα overexpression. Then, we found that C/EBPα promoted histone deacetylase 1 (HDAC1) transcription through binding to HDAC1 promoter. Moreover, HDAC1 deacetylated the activating transcription factor 4 (ATF4), a key positive regulator of ER stress. Trichostatin-A (an HDAC inhibitor) or ATF4 overexpression reversed the improvement of C/EBPα on OGD/R-induced ER stress and hepatocyte dysfunction. 4-Phenylbutyric acid (an endoplasmic reticulum stress inhibitor) also reversed the hepatic IR injury induced by ATF4 overexpression. Finally, lentivirus-mediated C/EBPα overexpression vector was applied to administrate hepatic IR mice, and the results showed that C/EBPα overexpression ameliorated IR-induced hepatic injury, manifesting with reduced ALT/AST, oxidative stress and ER stress. Altogether, our findings suggested that C/EBPα ameliorated hepatic IR injury by inhibiting ER stress via HDAC1-mediated deacetylation of ATF4 promoter.
肝缺血再灌注（IR）损伤是一个复杂的全身性过程，会引发一系列临床问题。C/EBPα是肝细胞功能的关键转录因子，但其在调节肝IR损伤中的作用和机制尚不清楚。采用阻断门静脉和肝动脉的方法建立小鼠肝IR损伤模型。与假手术组相比，IR损伤肝脏中C/EBPα表达降低，同时血清丙氨酸转氨酶（ALT）、天冬氨酸转氨酶（AST）、高迁移率族蛋白B1含量增加，肝细胞比例升高。采用氧糖剥夺/复氧（OGD/R）法在体外WRL-68肝细胞中建立细胞肝IR模型，并在肝细胞中过表达C/EBPα以评估其对肝IR损伤的影响。OGD/R促进肝细胞氧化应激、细胞凋亡和内质网（ER）应激，而C/EBPα过表达可逆转这些现象。然后，我们发现C/EBPα通过与HDAC1启动子结合促进组蛋白去乙酰化酶1（HDAC1）转录。此外，HDAC1使ER应激的关键正向调节因子激活转录因子4（ATF4）去乙酰化。曲古抑菌素A（一种HDAC抑制剂）或ATF4过表达可逆转C/EBPα对OGD/R诱导的ER应激和肝细胞功能障碍的改善作用。4-苯基丁酸（一种内质网应激抑制剂）也可逆转ATF4过表达诱导的肝IR损伤。最后，将慢病毒介导的C/EBPα过表达载体应用于肝IR小鼠，结果表明C/EBPα过表达可改善IR诱导的肝损伤，表现为ALT/AST、氧化应激和ER应激降低。总之，我们的研究结果表明，C/EBPα通过HDAC1介导的ATF4启动子去乙酰化抑制ER应激，从而改善肝IR损伤。
