Department of Traditional and Western Medical Hepatology, Third Hospital of Hebei Medical University, 050051 Shijiazhuang, China; Hebei Provincial Key Laboratory of Liver Fibrosis in Chronic Liver Diseases, China.
Department of Traditional and Western Medical Hepatology, Third Hospital of Hebei Medical University, 050051 Shijiazhuang, China; Hebei Provincial Key Laboratory of Liver Fibrosis in Chronic Liver Diseases, China.
Life Sci. 2020 Jul 15;253:117678. doi: 10.1016/j.lfs.2020.117678. Epub 2020 May 3.
The endoplasmic reticulum (ER) stress response plays a crucial role in the development of nonalcoholic steatohepatitis (NASH). Heme oxygenase-1 (HO-1) exerts beneficial effects against oxidative injury in NASH. This study is aimed to clarify whether HO-1 is an effective therapeutic strategy for NASH via regulation of ER stress.
The C57BL/6J mice were fed with methionine-choline deficient (MCD) for 4 weeks and high fat-high carbohydrate-high cholesterol (HFD) diet for 16 weeks, with hemin or zinc protoporphyrin IX (ZnPP-IX), respectively. The LO-2 cells were cultured in palmitic medium, with transfected pEX-HO-1 or sh-HO-1 plasmid for 24 h. Meanwhile, thirty NASH patients and 15 health controls were enrolled. The ER ultrastructure was observed by transmission electron microscopy (TEM) and confocal microscopy. The expressions of mRNAs and proteins of HO-1, ER stress related genes were detected by real time PCR, western blot and immunohistochemical staining, respectively.
The swelled and broken rough endoplasmic reticulums were observed in MCD and HFD fed mice. The reactive hepatic expression of HO-1 was related with the increased ROS production and ER stress, companied with upregulation of GRP78, p-IRE1, PERK, ATF6. Through hemin administration, hepatocyte apoptosis was suppressed companied down-regulation of CHOP, caspase12 and up-regulation of BCL2. Conserved results were exhibited in ZnPP-IX administrated mice and HO-1 silent cells. Consistent results were observed in the NASH Patients.
HO-1 could serve as a protective factor in the progression of nutritional steatohepatitis by suppresses hepatocyte excessive ER stress and might be a potential target for therapy of nonalcoholic steatohepatitis.
内质网（ER）应激反应在非酒精性脂肪性肝炎（NASH）的发展中起着至关重要的作用。血红素加氧酶-1（HO-1）在 NASH 的氧化损伤中发挥有益作用。本研究旨在通过调节 ER 应激来阐明 HO-1 是否是治疗 NASH 的有效策略。
将 C57BL/6J 小鼠分别用蛋氨酸-胆碱缺乏（MCD）喂养 4 周和高脂肪-高碳水化合物-高胆固醇（HFD）喂养 16 周，并用血红素或锌原卟啉 IX（ZnPP-IX）处理。将 LO-2 细胞在棕榈酸培养基中培养，用转染的 pEX-HO-1 或 sh-HO-1 质粒转染 24 小时。同时，纳入 30 名 NASH 患者和 15 名健康对照者。通过透射电子显微镜（TEM）和共聚焦显微镜观察 ER 超微结构。实时 PCR、Western blot 和免疫组织化学染色分别检测 HO-1、ER 应激相关基因的 mRNA 和蛋白表达。
在 MCD 和 HFD 喂养的小鼠中观察到肿胀和破裂的粗面内质网。HO-1 的反应性肝表达与 ROS 产生和 ER 应激的增加有关，同时伴有 GRP78、p-IRE1、PERK、ATF6 的上调。通过血红素给药，抑制了肝细胞核因子 4α（NF-κB）的激活，抑制了细胞凋亡，同时下调了 CHOP、caspase12 并上调了 BCL2。在 ZnPP-IX 处理的小鼠和沉默 HO-1 的细胞中观察到一致的结果。在 NASH 患者中也观察到一致的结果。
HO-1 可通过抑制肝细胞过度 ER 应激作为营养性脂肪性肝炎进展的保护因子，可能成为治疗非酒精性脂肪性肝炎的潜在靶点。
