Electroacupuncture protects intestinal barrier integrity in MAFLD mice and is associated with a macrophage α7nAChR/exosomal miR-217-5p/epithelial HO-1 signaling axis.

OBJECTIVE

The aim of this study was to identify how electroacupuncture (EA) maintains intestinal barrier integrity in metabolic dysfunction-associated fatty liver disease (MAFLD) and related to a macrophage α7 nicotinic acetylcholine receptor (α7nAChR)-linked exosomal miR-217-5p/epithelial HO-1 signaling.

METHODS

Control and intestinal epithelial-specific HO-1 knockout mice fed Western diet were treated with EA at ST-36 in the presence of further α7nAChR blockade or miR-217-5p agomir/antagomir intervention. The polarization of macrophages, exosome transfer, exosomal miRNA profiling, and target validation were evaluated using U937-derived macrophages and Caco-2/HT-29 epithelial cells.

RESULTS

EA recovered intestinal architecture, enhanced tight junction protein expression and decreased circulating endotoxin and D-lactate. These barrier-associated changes were accompanied by reduced hepatic steatosis and improved metabolic abnormalities. EA was associated with enhanced α7nAChR signaling in intestinal macrophages, reduced M1-like polarization, promoted M2-like features, and increased epithelial HO-1 expression. Exosomes of α7nAChR-stimulated macrophages were taken up by epithelial cells and inhibited the barrier dysfunction caused by lipopolysaccharide as demonstrated by the upregulation of ZO-1, Occludin, and Claudin-1 and elevated transepithelial electrical resistance. Small RNA sequencing and validation revealed that miR-217-5p is one of the primary exosomal mediators that are increased in M1 macrophage-derived exosomes but decreased following α7nAChR stimulation. miR-217-5p was a direct target of HMOX1 and its inhibition recovered epithelial HO-1 levels and barrier function, but HO-1 knockdown eliminated this defense. In vivo, miR-217-5p suppression augmented and miR-217-5p overexpression or epithelial HO-1 deficiency undermined the positive impacts of EA.

CONCLUSION

These findings support the involvement of a macrophage α7nAChR-associated exosomal miR-217-5p/epithelial HO-1 pathway in EA-mediated intestinal barrier protection and MAFLD improvement. EA may represent an adjunctive strategy for MAFLD.