Intestinal NLRP3 Deficiency Exacerbates MASLD in Male Mice via Reduced Butyrate Production

ABSTRACT Objectives Metabolic dysfunction–associated steatotic liver disease (MASLD) represents a major global health burden, yet its underlying mechanisms remain incompletely defined. We aimed to investigate the role of intestinal NOD‐, LRR‐, and pyrin‐domain‐containing protein 3 (NLRP3) inflammasome in the gut–liver axis to identify potential therapeutic targets for MASLD. Methods Eight‐week‐old male mice were given a methionine‐choline‐deficient (MCD) diet for 4 weeks to induce MASLD‐associated fibrosis. The functional role of NLRP3 was assessed using Vil1 cre Nlrp3 f/f mice with intestinal epithelial cell‐specific Nlrp3 deletion. To evaluate the potential influence of the gut microbiota, Vil1 cre Nlrp3 f/f ‐MCD mice were co‐housed with Nlrp3 f/f ‐MCD counterparts. The effect of butyrate was also evaluated in Vil1 cre Nlrp3 f/f ‐MCD mice via oral gavage for 3 weeks. The role of intestinal NLRP3 was further validated in a carbon tetrachloride (CCl 4 )‐induced liver fibrosis model. Results Intestinal NLRP3 expression was markedly reduced in wild‐type mice given MCD diet. Compared with Nlrp3 f/f ‐MCD mice, Vil1 cre Nlrp3 f/f ‐MCD mice developed more severe MASLD and exhibited impaired intestinal barrier integrity, whereas the co‐housing condition alleviated hepatic pathology. Moreover, butyrate administration significantly improved hepatic steatosis and fibrosis in Vil1 cre Nlrp3 f/f ‐MCD mice. Mechanistic analysis revealed attenuated hepatic peroxisome proliferator‐activated receptor α (PPARα) activation and enhanced hepatic activator protein (AP)‐1 signaling in Vil1 cre Nlrp3 f/f ‐MCD mice, both of which improved under co‐housing condition or butyrate treatment. Similarly, intestinal Nlrp3 deletion aggravated CCl 4 ‐induced liver fibrosis. Conclusion Loss of intestinal Nlrp3 diminished butyrate production, inhibited PPARα expression, and enhanced AP‐1 signaling, collectively intensifying MASLD progression.