Figure 1: Identification of microbial 5-ASA inactivating enzymes from IBD microbiome population multi-omics.

As part of the HMP2 IBDMDB (timeline, upper left),²² 132 participants with and without IBD were followed for 1 year, each completing multiple dietary and medication questionnaires, and each providing stool every two weeks and blood samples approximately quarterly. After excluding participants without IBD or without metabolomics data, we identified 45 verified users of 5-ASA in the cohort and 34 non-users. Among 5-ASA users, we found 13 individuals who started or resumed using the drug during the cohort follow-up. Stool from >1,000 samples was then profiled through metagenomics, metatranscriptomics, and/or metabolomics; blood was analyzed by exome sequencing which was ultimately leveraged to determine human NAT2 acetylation phenotypes (“fast” vs. “slow”) for our clinical exploration. In the analysis phase, we first studied the impact of 5-ASA on the fecal metabolome and then identified gut bacterial enzymes involved in inactivating 5-ASA to N-acetyl 5-ASA. Finally, we related these enzymes to risk of disease relapse.