Human Milk Oligosaccharides 2’-Fucosyllactose Alleviates Intestinal Inflammation by Regulating Bile Acid Metabolizing Enzymes

• 2′-FL can alleviate the symptoms of colitis in mice. • 2′-FL can regulate the composition of gut microbiota and reverse dysbiosis. • 2′-FL can regulate bile acid metabolic enzymes and balance bile acid metabolism. Ulcerative colitis (UC) is a chronic disease with an increasing incidence worldwide. 2’-Fucosyllactose (2’-FL) is the most abundant fucosylated neutral human milk oligosaccharides (HMOs), accounting for approximately 31% of the total HMOs content, and shows considerable potential in alleviating UC. This study aimed to investigate the therapeutic effect of 2’-FL on DSS-induced colitis in mice and explore its potential mechanisms. The results showed that HMO alleviated the symptoms of DSS-induced colitis in mice by alleviating weight loss, reducing the disease activity index (DAI), increasing the length of the mouse colon and improving the spleen index; HMO enhanced intestinal barrier function by repairing colon tissue damage, reducing intestinal permeability (DAO and D-LA), increasing the expression of Tight junctions (TJs), promoting the production of anti-inflammatory factor IL-10, and inhibiting cytokines (IL-1β, IL-6, and TNF-α). In addition, the activation of the colitis-related NF-κB pathway was significantly inhibited after HMO intervention. Furthermore, metagenomic analysis revealed that HMO intervention in colitis mice significantly increased the relative abundance of Bacteroidetes, Parabacteroidetes, Parabacteroides and Prevotella .; non-targeted metabolomics analysis demonstrated that HMO modulated the host's bile acid metabolism by preserving the level of deoxycholic acid. To further investigate the molecular mechanisms affecting bile acid metabolism, enzyme scanning was performed based on species-level genome enriched in different groups. The results showed that the bacteria mainly enriched in the HMO treatment group showed greater potential in encoding bile salt hydrolases (BSH) responsible for the dissociation of primary bile acids and 7α-hydroxysteroid dehydrogenases (7α-HSDs) that produce secondary bile acids. In summary, this study showed that HMO intervention changed the composition of the intestinal flora, and the specially enriched intestinal microorganisms regulated the host's secondary bile acid metabolism, thereby effectively alleviating colon inflammation in mice. Gut microbiome determines therapeutic effects of 2′-fucosyllactose on DSS-induced colitis by modulating bile acid metabolism. (Created in BioRender. Harry, P. (2024) https://BioRender.com/d84c944 )