Akkermansia muciniphila exacerbates acute radiation-induced intestinal injury by depleting mucin and enhancing inflammation

Dysbiosis of gut microbiota plays a crucial role in acute radiation-induced intestinal injury. However, studies on the influence of gut microbiota on acute radiation-induced intestinal injury are inconsistent. In this study, we established an acute radiation-induced intestinal injury mouse model and performed fecal microbiota transplantation to explore the role of the gut microbiota in acute radiation-induced intestinal injury. We observed a significant increase in Akkermansia muciniphila following irradiation, whereas fecal microbiota transplantation effectively reduced Akkermansia muciniphila levels. Contrary to expectations, Akkermansia muciniphila supplementation increased acute radiation-induced intestinal injury and mortality. Mechanistically, post-radiation Akkermansia muciniphila upregulates mucin metabolism genes and consumes mucin, thinning the mucosal barrier and promoting the adhesion and translocation of potential pathogens to epithelial cells, thus exacerbating acute radiation-induced intestinal injury. This enables Akkermansia muciniphila to use mucin as an energy source. Additionally, Akkermansia muciniphila increases the inflammatory macrophage changes and secretion of inflammatory cytokines, leading to a decrease in epithelial stem cell density and inhibition of goblet cell differentiation, further exacerbating acute radiation-induced intestinal injury. Our findings suggest that in certain intestinal environments, the addition of Akkermansia muciniphila may worsen radiation-induced intestinal damage; thus, alternative approaches to reverse the dysbiosis associated with radiotherapy should be explored.