This proposal capitalizes on a unique team of investigators with complementary expertise to delineate and exploitthe mechanistic relationships between diet, the microbiota, and inflammatory bowel disease and thus establisha framework for mapping diet-microbiota-host interactions for many biological signatures of interest. We willengineer and test an unconventional synbiotic therapy (nutrients plus microbes) for treating ulcerative colitis(UC), with in silico, ex vivo, and in vivo validation and approaches with generalizability to synbiotic formulationsfor many diseases. Extensive research has been performed on the anti-inflammatory role of the gut microbiota,primarily mediated through endogenous microbial molecules and fermentation end products . However, fewinvestigators have explored the capacity of the gut microbiota to metabolize bioactive molecules, specificallyplant-derived dietary metabolites that ameliorate gut inflammation. Among these phytochemicals areglucosinolates, low molecular weight S-linked glycosides present in all members of the Brassicaceae family (e.g.,cabbage, radishes) . Glucosinolates are precursor metabolites for microbe-derived isothiocyanates (ITCs),anti-inflammatory agents that act on NF-?B and Nrf2 [5,6]. Optimal synthesis of isothiocyanates is dependentupon environmental factors that include a metabolic profile established by the gut microbiome although themechanisms are poorly understood . Using computational tools and multi-omic approaches, the outlinedknowledge gap of microbe-mediated conversion of a key glucosinolate (glucoraphanin or GRN) to a keyisothiocyanate (sulforaphane or SFN) presents a profound opportunity to identify bacterial species with definedcapacity for optimal phytochemical processing, host responses, and subsequent mechanisms of benefit to hosthealth. The long-term goal is to maximize localized delivery of isothiocyanates to inflamed tissue(s) throughmanipulation of the gut microbiota and phytochemical supplementation. The rationale for the proposed researchis that once a mechanistic understanding of these conditions and species is achieved, tailored synbiotic therapiesbecome a possibility. We plan to test our central hypothesis that specific bacteria have a mitigating effect oninflammatory bowel disease by metabolizing a plant-derived glucosinolate into an anti-inflammatoryisothiocyanate by pursuing the following three specific aims: (1) Delineate mechanisms of SFN production byknown microbial species. (2) Employ ex vivo human colonoids to test the impact of SFN on intestinal epithelialhomeostasis. (3) Elucidate the impact of selected synbiotics on localized SFN bioavailability in murine colitis.The proposed program will be implemented by investigators with expertise in metabolic modeling and omicstechnologies (Dr. Papin), enteroid models and gastroenterology (Drs. Moore and Rosen), and in vivo mousemodels (Drs. Kolling, Moore, and Rosen). We anticipate that completion of this work will generate mechanisticunderstanding of patient-centric synbiotic therapies for ulcerative colitis and other intestinal inflammatorydisorders tailored to the individualized gut environment.