Capsaicin modulates Akkermansia muciniphila abundance by enhancing MUCIN2 levels in mice fed with high-fat diets

Extensive research has been conducted to investigate the impact of capsaicin (CAP) on lipid metabolism, focusing specifically on its interaction with the vanilloid subtype 1 (TRPV1) ion channel. Additionally, studies have illuminated the role of Akkermansia muciniphila (A. muciniphila), a specific strain of intestinal microbiota, in lipid metabolism. In this study, a model utilizing resiniferatoxin (RTX) was employed to deactivate TRPV1 ion channels in germ-free mice, followed by the administration of A. muciniphila via gavage. Following the collection of intestinal tissues for a comprehensive analysis, employing histopathology, qPCR, and ELISA techniques, our findings revealed a significant upregulation of MUC2 and MUC3 expression induced by CAP. This upregulation resulted in the thickening of the colonic mucus layers. Notably, this effect was absent when TRPV1 was selectively inhibited. Moreover, there was no discernible impact on goblet cells. The findings strongly indicate that CAP influences the system by activating the TRPV1 ion channel, thereby enhancing the expression of mucin MUC2 and promoting an augmentation in the thickness of the mucous layer. This activation, in turn, supplies A. muciniphila with an ample source of carbon and nitrogen. This insight potentially clarify the underlying mechanism through which CAP facilitates the increase in A. muciniphila abundance