Zhu Ying, Yang Meng, Li Xue-Hui, Xu Wu-Jian, Gao Wei, Chen Yu-Han, Li Jian-Dong, Li Qiang
Department of Respiratory and Critical Care Medicine, Seventh Medical Center of Chinese PLA General Hospital, Beijing, China.
Department of Geriatrics, Changhai Hospital, Navy Military Medical University, Shanghai, China.
Ann Transl Med. 2021 Apr;9(7):563. doi: 10.21037/atm-20-6143.
Idiopathic pulmonary fibrosis (IPF) is a fatal chronic pulmonary fibrosis disease and pathological mechanisms of fibrogenesis in IPF are still to be elucidated. Here, we investigated the potential role of Nogo-B in pulmonary fibrogenesis.
A mouse model of pulmonary fibrosis was established by intratracheal injection of bleomycin (BLM). Lung epithelial cells MLE-12 and TC-1 JHU-1 were cultured for TGF-β treatment. The extent of lung fibrosis was evaluated using hematoxylin and eosin (HE) staining and Masson staining in model mice and Nogo-B knockout mice. The protein levels of Nogo-B, endoplasmic reticulum stress (ERS) sensors including PERK, IRE1α, ATF6 and epithelial-mesenchymal transition (EMT) markers including E-cadherin and N-cadherin, vimentin were assayed by Western blotting respectively after Nogo-B knockdown or overexpression with lentivirus. Enzyme-linked immunosorbent assay (ELISA) was used to evaluate cytokine levels of TGF-β, TNF-α, IL-1β, IL-6 and IL-10 in bronchoalveolar lavage fluid (BALF).
Nogo-B expression was up-regulated in lung tissues of fibrosis model mice and alveolar epithelial cells. Nogo-B knockdown significantly attenuated lung fibrogenesis, downregulated the levels of inflammatory cytokines, inhibited EMT as well as decreased the level of phosphor-PERK/PERK but not the levels of phosphor-IRE1α/IRE1α and c-ATF6. Additionally, a potential efficacy of PERK blockade was demonstrated in improving the extent of lung fibrosis in model mice.
This study discovered that involvement of Nogo-B in pulmonary fibrogenesis was associated with the PERK branch of ERS pathway and EMT. Nogo-B could be considered as a potential therapeutic target for the treatment of IPF.
特发性肺纤维化（IPF）是一种致命的慢性肺纤维化疾病，IPF 中纤维化形成的病理机制仍有待阐明。在此，我们研究了 Nogo-B 在肺纤维化形成中的潜在作用。
通过气管内注射博来霉素（BLM）建立肺纤维化小鼠模型。培养肺上皮细胞 MLE-12 和 TC-1 JHU-1 用于转化生长因子-β（TGF-β）处理。在模型小鼠和 Nogo-B 基因敲除小鼠中，使用苏木精和伊红（HE）染色及 Masson 染色评估肺纤维化程度。在用慢病毒敲低或过表达 Nogo-B 后，分别通过蛋白质印迹法检测 Nogo-B、内质网应激（ERS）传感器包括 PERK、IRE1α、ATF6 的蛋白水平以及上皮-间质转化（EMT）标志物包括 E-钙黏蛋白、N-钙黏蛋白、波形蛋白的蛋白水平。采用酶联免疫吸附测定（ELISA）评估支气管肺泡灌洗液（BALF）中 TGF-β、肿瘤坏死因子-α（TNF-α）、白细胞介素-1β（IL-）、白细胞介素-6（IL-6）和白细胞介素-10（IL-10）的细胞因子水平。
Nogo-B 在纤维化模型小鼠的肺组织和肺泡上皮细胞中表达上调。敲低 Nogo-B 可显著减轻肺纤维化，下调炎性细胞因子水平，抑制 EMT，同时降低磷酸化 PERK/PERK 水平，但不影响磷酸化 IRE1α/IRE1α 和裂解型 ATF6 的水平。此外，还证明了 PERK 阻断在改善模型小鼠肺纤维化程度方面具有潜在疗效。
本研究发现 Nogo-B 参与肺纤维化形成与 ERS 途径的 PERK 分支及 EMT 相关。Nogo-B 可被视为治疗 IPF 的潜在治疗靶点。
