Li Ying, Xiao Guangzhi, Fu Xianghui, Luo Xing, Yang Fengfan, Li Yadan, Zheng Zhaohui
Department of Clinical Immunology, Xijing Hospital, Fourth Military Medical University, Xi'an, China.
Department of Clinical Immunology, Xijing Hospital, Fourth Military Medical University, Xi'an, China.
Immunobiology. 2025 May;230(3):152908. doi: 10.1016/j.imbio.2025.152908. Epub 2025 Apr 24.
Chronic obstructive pulmonary disease (COPD) is intricately linked to pulmonary fibrosis, yet the underlying mechanisms remain unclear. This study investigates whether CH25H/25-hydroxycholesterol (25-HC) promotes pulmonary fibrosis in COPD by modulating AMPK/STAT6-dependent M2 macrophage polarization.
Using GEO datasets and a cigarette smoke-induced COPD mouse model, we analyzed CH25H expression and fibrotic pathology. CH25H was silenced via adeno-associated virus (AAV)-delivered shRNA. Histopathology, flow cytometry, qPCR, and Western blotting assessed fibrosis, macrophage polarization (M1/M2), and AMPK/STAT6 pathway activity. Bone marrow-derived macrophages (BMDMs) were employed to validate polarization mechanisms. The role of the AMPK/STAT6 pathway was investigated using the specific activator.
Analysis of the GEO database and experimental verification showed significantly increased CH25H expression in both lung tissues and macrophages from COPD mice. CH25H knockdown alleviated alveolar damage, airway remodeling, and pulmonary fibrosis in COPD mice, evidenced by reduced expression of fibrosis-related proteins, improved lung function, and attenuated inflammatory responses. Moreover, CH25H knockdown inhibited M2 macrophage polarization and decreased the proportion of M2-type macrophages. Importantly, decreased levels of 25-HC following CH25H knockdown were asso ciated with suppressed activation of the AMPK/STAT6 pathway. Rescue experiments demonstrated that the protective effects of CH25H knockdown could be reversed by adding the AMPKα activator GSK621.
Our findings demonstrate that CH25H/25-HC exacerbates COPD-associated pulmonary fibrosis by promoting AMPK/STAT6-dependent M2 macrophage polarization. Targeting CH25H may represent a novel therapeutic strategy for mitigating fibrosis in COPD.
慢性阻塞性肺疾病（COPD）与肺纤维化密切相关，但其潜在机制尚不清楚。本研究旨在探讨胆固醇25-羟化酶（CH25H）/25-羟基胆固醇（25-HC）是否通过调节AMPK/STAT6依赖的M2巨噬细胞极化来促进COPD中的肺纤维化。
利用基因表达综合数据库（GEO）数据集和香烟烟雾诱导的COPD小鼠模型，分析CH25H表达和纤维化病理。通过腺相关病毒（AAV）介导的短发夹RNA沉默CH25H。采用组织病理学、流式细胞术、定量聚合酶链反应（qPCR）和蛋白质免疫印迹法评估纤维化、巨噬细胞极化（M1/M2）和AMPK/STAT6信号通路活性。采用骨髓来源的巨噬细胞（BMDM）验证极化机制。使用特异性激活剂研究AMPK/STAT6信号通路的作用。
GEO数据库分析和实验验证表明，COPD小鼠肺组织和巨噬细胞中CH25H表达显著增加。CH25H基因敲低减轻了COPD小鼠的肺泡损伤、气道重塑和肺纤维化，表现为纤维化相关蛋白表达降低、肺功能改善和炎症反应减轻。此外，CH25H基因敲低抑制了M2巨噬细胞极化，降低了M2型巨噬细胞的比例。重要的是，CH25H基因敲低后25-HC水平降低与AMPK/STAT6信号通路激活受抑制有关。挽救实验表明，添加AMPKα激活剂GSK621可逆转CH25H基因敲低的保护作用。
我们的研究结果表明，CH25H/25-HC通过促进AMPK/STAT6依赖的M2巨噬细胞极化加重COPD相关的肺纤维化。靶向CH25H可能是减轻COPD纤维化的一种新的治疗策略。
