Hexadecanamide-dosed mice alleviates experimental colitis and modify the gut microbiome

Hexadecanamide (HEX), a metabolite from the rumen fluid of Subacute ruminal acidosis (SARA) cows, is known to be beneficial in inflammation alleviation. However, the precise role and mechanism of HEX in colitis remain unknown. Herein, we first determined the effect of oral HEX on DSS-induced colitis in mice. Our results showed HEX alleviated DSS-induced colitis in mice, which was related to improvement of intestinal barrier integrity and the reduction of colonic inflammatory responses. Interestingly, HEX depressed DSS-induced initiation of ferroptosis. In detail, HEX inhibited autophagy and ferritinophagy, which subsequently blocked lipid peroxidation. 16S rRNA sequencing revealed that HEX intervention regulated the gut microbial composition, manifesting as increased the abundance of Actinobacteriota and Patescibacteria and decreased the relative abundance of Firmicutes. Particularly, HEX treatment enriched beneficial bacteria such as Bifidobacterium and Romboutsia. To validate these findings, we performed fecal microbiota transplantation (FMT) to DSS-treated mice. Microbiota from HEX-treated mice mitigated the colitis than microbiota from Control-treated mice shown by eminently anti-inflammatory effects and colonic barrier repair, and also enriched beneficial bacteria such as Turicibacter and Bacteroides, which was further confirmed by FMT.