Chen Yi, Xie Kangjie, Chen Caiyang, Wang Xihui, Ma Chenchen, Huang Zhangxiang, Jiao Yingfu, Yu Weifeng
Department of Anesthesiology, Renji Hospital, Jiaotong University School of Medicine, No. 160, Pujian Road, Pudong New District, Shanghai, 200217, China.
Key Laboratory of Anesthesiology, Shanghai Jiao Tong University, Ministry of Education, Shanghai, 200217, China.
Mol Med. 2025 May 30;31(1):213. doi: 10.1186/s10020-025-01275-6.
Metabolic dysfunction-associated steatohepatitis (MASH) is one of the most common chronic liver diseases worldwide, and specific treatment modalities are lacking. Accumulating evidence suggests that hepatic inflammation plays a key role in the progression from hepatic steatosis to MASH. Macrophages, especially anti-inflammatory macrophages, serve as natural immune cells that maintain homeostasis in the immune microenvironment. Here, we aimed to reveal the role of anti-inflammatory macrophages in MASH and investigate the underlying mechanism involved.
METHODS & RESULTS: Extracellular vesicles (EVs) were isolated from the supernatant of anti-inflammatory bone marrow-derived macrophages (BMDMs) by ultracentrifugation, and their protein profile was characterized by liquid chromatography-tandem mass spectrometry (LC‒MS/MS) analysis. Murine hepatocytes were stimulated with palmitic acid (PA) followed by treatment with EVs or oxysterol-binding protein-related protein 8 (ORP8/Osbpl8) shRNA. C57BL/6 mice were fed a methionine- and choline-deficient (MCD) diet for 3 weeks to establish MASH. The mice were then treated with EVs or shRNA-encoding AAV. In vitro and ex vivo experiments revealed that extracellular vesicles derived from anti-inflammatory BMDMs inhibited inflammatory responses and alleviated lipotoxicity during MASH. We identified Osbpl8 as a vital component of M2-BMDMs by LC-MS/MS analysis and found that Osbpl8 remodels lipid metabolism by inhibiting excessive IRE1α-XBP1-related ER stress. Furthermore, Osbpl8-enriched M2-BMDM-EVs promoted anti-inflammatory and antilipotoxic effects and could be a novel therapeutic target for the clinical treatment of MASH.
Our findings indicate that Osbpl8 derived from EVs secreted by anti-inflammatory BMDMs plays important roles in intercellular communication between macrophages and hepatocytes, revealing a novel regulatory mechanism of macrophage homoeostasis in MASH.
代谢功能障碍相关脂肪性肝炎（MASH）是全球最常见的慢性肝病之一，且缺乏特异性治疗方法。越来越多的证据表明，肝脏炎症在从肝脂肪变性发展至MASH的过程中起关键作用。巨噬细胞，尤其是抗炎巨噬细胞，作为维持免疫微环境稳态的天然免疫细胞。在此，我们旨在揭示抗炎巨噬细胞在MASH中的作用，并探究其潜在机制。
通过超速离心从抗炎骨髓来源巨噬细胞（BMDMs）的上清液中分离细胞外囊泡（EVs），并通过液相色谱-串联质谱（LC-MS/MS）分析对其蛋白质谱进行表征。用棕榈酸（PA）刺激小鼠肝细胞，随后用EVs或氧化甾醇结合蛋白相关蛋白8（ORP8/Osbpl8）短发夹RNA（shRNA）处理。给C57BL/6小鼠喂食蛋氨酸和胆碱缺乏（MCD）饮食3周以建立MASH模型。然后用EVs或编码shRNA的腺相关病毒（AAV）处理小鼠。体外和体内实验表明，源自抗炎BMDMs的细胞外囊泡在MASH期间抑制炎症反应并减轻脂毒性。我们通过LC-MS/MS分析确定Osbpl8是M2-BMDMs的重要组成部分，并发现Osbpl8通过抑制过度的肌醇需求酶1α（IRE1α）-X盒结合蛋白1（XBP1）相关的内质网应激来重塑脂质代谢。此外，富含Osbpl8的M2-BMDM-EVs促进抗炎和抗脂毒性作用，可能成为MASH临床治疗的新靶点。
我们的研究结果表明，抗炎BMDMs分泌的EVs来源的Osbpl8在巨噬细胞与肝细胞之间的细胞间通讯中起重要作用，揭示了MASH中巨噬细胞稳态的新调控机制。
