FGF20 modulates gut microbiota to mitigate dextran sodium sulfate-induced ulcerative colitis in mouse models

•The objective of this study is to demonstrate the therapeutic potential of FGF20 in UC and elucidate its mechanism of action involving modulation of the intestinal microbiota.•A mouse model of UC was established using dextran sodium sulfate (DSS), and the therapeutic effects and mechanism of FGF20 were investigated.•Administration of adeno-associated virus overexpressing FGF20 resulted in a significant improvement in UC-associated phenotypes.•FGF20 significantly ameliorated the dysbiosis of gut microbiota in UC mice by increasing the abundance of beneficial bacteria and decreasing the abundance of harmful bacteria.•The therapeutic effects of FGF20 in UC mice were noticeably attenuated following depletion of microbiota using an antibiotic cocktail. Fecal microbiota transplantation experiments further supported the implication of the gut microbiota in the therapeutic effects of FGF20 on UC mice. Ulcerative colitis (UC), a prevalent form of inflammatory bowel disease (IBD), presents a significant clinical challenge due to the lack of optimal therapeutic strategies. Emerging evidence suggests that fibroblast growth factor 20 (FGF20) may play a crucial role in mitigating UC symptoms, though the mechanistic underpinnings remain elusive. In this study, a mouse model of UC was established using dextran sodium sulfate (DSS) to investigate the potential role of FGF20. Our findings revealed a marked reduction in FGF20 expression in the serum and colonic tissues of DSS-treated mice. Furthermore, FGF20 knockout did not exacerbate colonic damage in these mice. Conversely, overexpression of FGF20 via adeno-associated virus (AAV) significantly alleviated UC-associated symptoms. This alleviation was evidenced by attenuated intestinal shortening, mitigated weight loss, increased colonic goblet cell density and crypt formation, reduced inflammation severity and inflammatory cell infiltration, and enhanced expression of tight junction and mucin proteins. Moreover, FGF20 significantly ameliorated the dysbiosis of gut microbiota in DSS-treated mice by increasing the abundance of beneficial bacteria and decreasing the abundance of harmful bacteria. The beneficial effects of FGF20 were notably attenuated following gut microbiota depletion with an antibiotic regimen. Fecal microbiota transplantation experiments further supported the critical role of gut microbiota in mediating the effects of FGF20 on DSS-treated mice. In conclusion, these findings highlight the potential involvem