Exosomal PPAR? derived from macrophages suppresses LPS-induced peritonitis by negative regulation of CD14/TLR4 axis

作者：Meng, Meng; Lu, Meizhi; Feng, Junxia; Zhou, Xiaoying; Meng, Ping; Chen, Luxuan; Zou, Xunliang; Liu, Xiaohui; Liu, Langxia^*; Gao, Xuejuan^*; Zhang, Yunfang^*

来源：Inflammation Research, 2023, 72(8): 1567-1581.

DOI：10.1007/s00011-023-01765-5

• Macrophages
• Exosome
• PPAR & gamma
• LPS
• CD14
• TLR4
• Peritonitis

Background Intercellular communication between macrophages and peritoneal mesothelial cells (PMCs) has been suggested as a key factor regulating peritonitis development. Here, we explored whether PPAR? (peroxisome proliferator-activated receptor gamma) can be packaged into macrophage exosomes to mediate intercellular communication and regulate peritonitis.Methods Macrophage exosomes were isolated by ultracentrifugation and identified by nanoparticle tracking analysis and transmission electron microscopy. Proteomic analysis of macrophage-derived exosomes was performed using mass spectrometry. Co-culture models of supernatants or exosomes with PMCs, as well as a mouse peritonitis model induced by lipopolysaccharide (LPS), were employed.Results In this study, using stable Raw264.7 cells overexpressing GFP-FLAG-PPAR? (OE-PPAR?), we found that PPAR? inhibited LPS-induced inflammatory responses in Raw264.7 cells and that PPAR? was incorporated into macrophage exosomes during this process. Overexpression of PPAR? mainly regulated the secretion of differentially expressed exosomal proteins involved in the biological processes of protein transport, lipid metabolic process, cell cycle, apoptotic process, DNA damage stimulus, as well as the KEGG pathway of salmonella infection. Using co-culture models and mouse peritonitis model, we showed that exosomes from Raw264.7 cells overexpressing PPAR? inhibited LPS-induced inflammation in co-cultured human PMCs and in mice through downregulating CD14 and TLR4, two key regulators of the salmonella infection pathway. Pretreatment of the PPAR? inhibitor GW9662 abolished the anti-inflammatory effect of exosomes from Raw264.7 OE-PPAR? cells on human PMCs.Conclusions These results suggested that overexpression of PPAR? largely altered the proteomic profile of macrophage exosomes and that exosomal PPAR? from macrophages acted as a regulator of intercellular communication to suppress LPS-induced inflammatory responses in vitro and in vivo via negatively regulating the CD14/TLR4 axis.

• 单位
  南方医科大学; 5