Changes in tryptophan de novo NAD synthesis associated with chronic intestinal inflammation

Tryptophan metabolism and de novo NAD biosynthesis is associated with behavioural changes in IBD patients. The microbiota and tryptophan de novo syntheses of the distal colon, distal colon and brain of C57BL/6 control mice and Winnie mice littermates with chronic intestinal inflammation were compared using RNA-Seq. Differentially expressed genes were analysed using Micromon software. Changes in tryptophan and nicotinamide metabolism-associated gene expressions, metabolites, and abundance of gut microbiota associated with chronic intestinal inflammation and dysregulated tryptophan metabolism in the Winnie mouse distal colon and brain were apparent. Our findings shed light on the physiological alterations in tryptophan metabolism, specifically its diversion from the serotonergic pathway towards the kynurenine pathway and the consequential effects on de novo NAD+ synthesis, in the context of chronic intestinal inflammation