Background and aims <p>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.</p> Methods &amp; results <p>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.</p> Conclusions <p>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.</p>

错误:搜索内容不能为空,请输入英文关键词
错误:关键词超出字数限制,请精简
高级检索

BMDM-derived ORP8 suppresses lipotoxicity and inflammation by relieving endoplasmic reticulum stress in mice with MASH

  • Yi Chen,
  • Kangjie Xie,
  • Caiyang Chen,
  • Xihui Wang,
  • Chenchen Ma,
  • Zhangxiang Huang,
  • Yingfu Jiao,
  • Weifeng Yu

摘要

Background and aims

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.

Conclusions

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.