Hepatocyte Nicotinamide Adenine Dinucleotide Phosphate Reduced Oxidase 4 Regulates Stress Signaling, Fibrosis, and Insulin Sensitivity During Development of Steatohepatitis in Mice.
Hepatocyte Nicotinamide Adenine Dinucleotide Phosphate Reduced Oxidase 4 Regulates Stress Signaling, Fibrosis, and Insulin Sensitivity During Development of Steatohepatitis in Mice.
复制标题
DOI：
10.1053/j.gastro.2015.04.009
复制
发表时间：
2015-08
期刊：
影响因子：
29.4
通讯作者：
Török NJ
中科院分区：
文献类型：
--
作者：
Bettaieb A;Jiang JX;Sasaki Y;Chao TI;Kiss Z;Chen X;Tian J;Katsuyama M;Yabe-Nishimura C;Xi Y;Szyndralewiez C;Schröder K;Shah A;Brandes RP;Haj FG;Török NJ
活性氧化物种(ROS)被认为与非酒精性脂肪性肝炎(NASH)的进展有关。然而，人们对肝细胞中ROS的来源及其在疾病进展中的作用知之甚少。我们研究了NASH患者和脂肪性肝炎小鼠肝组织中NADPH氧化酶4(NOX4)的作用。肝活检标本取自加州大学戴维斯分校癌症中心生物库的5例NASH患者、4例单纯性脂肪变性患者和5例非脂肪变性患者(对照)。肝细胞特异性缺失NOX4的小鼠(NOX4HepKO)和NOX4flxp+/+C57BL/6小鼠(对照组)分别给予快餐(添加高果糖玉米糖浆)或胆碱缺乏的L(一种定义为诱发脂肪性肝炎的氨基酸)或对照饮食20周。另一组小鼠被给予NOX4抑制剂(GKT137831)。免疫印迹法检测肝组织中NOX4、炎症和纤维化标志物、双链RNA活化蛋白激酶(PKR)和磷酸化eIF-2α激酶(PERK)介导的应激信号通路。我们进行了高胰岛素-正血糖钳夹研究和免疫沉淀分析，以确定PP1C的氧化和磷酸酶活性。与对照组相比，NASH患者血清NOX4水平升高。肝细胞特异性缺失NOX4可降低饮食诱导脂肪性肝炎小鼠的氧化应激、脂质过氧化和肝纤维化。NOX4的小分子抑制剂减少了饮食诱导的脂肪性肝炎小鼠的肝脏炎症和纤维化，并增加了胰岛素敏感性。在原代肝细胞中，NOX4降低了磷酸酶PP1C的活性，延长了PKR的激活时间，并延长了PERK介导的应激信号。肝细胞特异性缺失NOX4的小鼠和服用GKT137831的小鼠胰岛素敏感性增加。NOX4调节肝脏中的氧化应激，其水平在NASH患者和饮食性脂肪性肝炎小鼠中增加。NOX4的抑制剂可以减轻肝脏炎症和纤维化，增加胰岛素敏感性，并可能被开发用于治疗NASH。
Reactive oxidative species (ROS) are believed to be involved in the progression of non-alcoholic steatohepatitis (NASH). However, little is known about the sources of ROS in hepatocytes or their role in disease progression. We studied the effects of NADPH oxidase 4 (NOX4) in liver tissues from patients with NASH and mice with steatohepatitis. Liver biopsy samples were obtained from 5 patients with NASH, as well as 4 patients with simple steatosis and 5 patients without steatosis (controls) from the University of California, Davis Cancer Center Biorepository. Mice with hepatocyte-specific deletion of NOX4 (NOX4hepKO) and NOX4floxp+/+ C57BL/6 mice (controls) were given fast food diets (supplemented with high-fructose corn syrup) or choline-deficient L-amino acid-defined to induce steatohepatitis, or control diets, for 20 weeks. A separate group of mice were given the NOX4 inhibitor (GKT137831). Liver tissues were collected and immunoblot analyses were performed determine levels of NOX4, markers of inflammation and fibrosis, double-stranded RNA-activated protein kinase (PKR), and phospho-eIF-2alpha kinase (PERK)-mediated stress signaling pathways. We performed hyperinsulinemic-euglycemic clamp studies and immunoprecipitation analyses to determine the oxidation and phosphatase activity of PP1C. Levels of NOX4 were increased in patients with NASH, compared with controls. Hepatocyte-specific deletion of NOX4 reduced oxidative stress, lipid peroxidation, and liver fibrosis in mice with diet-induced steatohepatitis. A small molecule inhibitor of NOX4 reduced liver inflammation and fibrosis and increased insulin sensitivity in mice with diet-induced steatohepatitis. In primary hepatocytes, NOX4 reduced the activity of the phosphatase PP1C, prolonging activation of PKR and PERK-mediated stress signaling. Mice with hepatocyte-specific deletion of NOX4 and mice given GKT137831had increased insulin sensitivity. NOX4 regulates oxidative stress in the liver and its levels are increased in patients with NASH and mice with diet-induced steatohepatitis. Inhibitors of NOX4 reduce liver inflammation and fibrosis and increase insulin sensitivity, and might be developed for treatment of NASH.