Zheng Yu, Tao Yingying, Zhan Xiaobo, Wu Qi
Hepatobiliary Pancreatic Surgery Department, Tongde Hospital of Zhejiang Province, Hangzhou, China.
Emergency Intensive Care Unit, Hangzhou Ninth People's Hospital, Hangzhou, China.
Bioengineered. 2022 Apr;13(4):8349-8359. doi: 10.1080/21655979.2022.2053804.
The nuclear receptor 4A1 (NR4A1) is widely involved in the regulation of cell survival and is related to ischemic injury in several organs. This research examined the emerging role and mechanism of NR4A1 in hepatocyte ischemia-reperfusion injury (IRI). BRL-3A cells were subjected to hypoxia-reperfusion (H/R) to simulate an IRI model . The expression of NR4A1 and liver kinase B1 (LKB1)/AMP-activated protein kinase (AMPK) pathway-related proteins (LKB1, AMPK, and ACC) was detected by western blotting or RT-qPCR under H/R condition after NR4A1 overexpression or silencing. Then, radicicol, an inhibitor of LKB1 pathway, was used to determine the role of NR4A1 in hepatocyte H/R injury by regulating LKB1. Under the help of CCK-8 assay, cell viability was assessed. The levels of ROS, MDA, and SOD were determined with corresponding kits to evaluate oxidative stress. Additionally, RT-qPCR was employed to analyze the releases of the inflammatory factors. Flow cytometry was applied to estimate the apoptosis and its related proteins, and autophagy-associated proteins were assayed by western blotting. Results indicated that NR4A1 was highly expressed, while proteins in LKB1/AMPK signaling was downregulated in BRL-3A cells exposed to H/R. The activation of LKB1/AMPK pathway could be negatively regulated by NR4A1. Moreover, NR4A1 depletion conspicuously promoted cell viability, inhibited oxidative stress as well as inflammation, and induced apoptosis and autophagy in H/R-stimulated BRL-3A cells, which were reversed after radicicol intervention. Collectively, NR4A1/LKB1/AMPK axis is a new protective pathway involved in hepatocyte IRI, shedding new insights into the improvement of hepatocyte IRI.
核受体4A1(NR4A1)广泛参与细胞存活的调节,并与多个器官的缺血性损伤有关。本研究探讨了NR4A1在肝细胞缺血再灌注损伤(IRI)中的新作用及机制。对BRL-3A细胞进行缺氧复灌注(H/R)以模拟IRI模型。在过表达或沉默NR4A1后,通过蛋白质免疫印迹法或逆转录定量聚合酶链反应(RT-qPCR)检测H/R条件下NR4A1以及肝激酶B1(LKB1)/AMP活化蛋白激酶(AMPK)信号通路相关蛋白(LKB1、AMPK和乙酰辅酶A羧化酶(ACC))的表达。然后,使用LKB1信号通路抑制剂萝卜硫素,通过调节LKB1来确定NR4A1在肝细胞H/R损伤中的作用。借助细胞计数试剂盒(CCK-8)检测评估细胞活力。使用相应试剂盒测定活性氧(ROS)、丙二醛(MDA)和超氧化物歧化酶(SOD)水平以评估氧化应激。此外,采用RT-qPCR分析炎症因子的释放情况。运用流式细胞术评估细胞凋亡及其相关蛋白,并通过蛋白质免疫印迹法检测自噬相关蛋白。结果表明,在经历H/R的BRL-3A细胞中,NR4A1高表达,而LKB1/AMPK信号通路中的蛋白表达下调。NR4A1可负向调节LKB1/AMPK信号通路的激活。此外,在H/R刺激的BRL-3A细胞中,敲低NR4A1可显著提高细胞活力,抑制氧化应激和炎症,并诱导细胞凋亡和自噬,而萝卜硫素干预后这些作用得到逆转。总体而言,NR4A1/LKB1/AMPK轴是参与肝细胞IRI的一条新的保护途径,为改善肝细胞IRI提供了新的见解。