Metabolomics reveals the impact of vitamin D on the microbiome (MUC4P.856)

Dysbiosis of the microbiome is an important factor in susceptibility to diseases such as inflammatory bowel disease (IBD). Vitamin D has known immunoregulatory roles and decreased levels of vitamin D are linked to IBD. Mice lacking the enzyme 1-α-hydroxylase (Cyp27B1 KO) cannot metabolize 25(OH)D 3 into bio-active 1,25(OH) 2 D 3 . These mice are more susceptible to experimental colitis compared to WT controls. Here we wanted to determine the effect of vitamin D 3 on the urinary metabolome, since microbial metabolites can be detected in urine. Urine was collected from WT, WT+20,000IU vitamin D 3 , and WT and Cyp27B1 KO littermates. Urine samples were profiled by ultra-performance liquid chromatography coupled with electrospray ionization quadrupole time-of-flight mass spectrometry (UPLC-ESI-QTOFMS) and multivariate data analysis tools. WT mice supplemented with vitamin D and WT and Cyp27B1 KO mice displayed changes in microbial metabolites compared to unsupplemented mice. Metabolites associated with the gut microbiota: p-cresol sulfate, indoxyl sulfate, xanthurenic acid, and betaine were different as a function of vitamin D 3 supplementation or Cyp27B1 expression. Alterations in the urinary metabolome suggest a role for vitamin D 3 in regulating the microbiota. Metabolite analysis will aid our understanding of the mechanisms by which vitamin D 3 affects host health and the microbiota, and future work will address how changes in the microbiota affect susceptibility to experimental IBD.