Karthikeyani Chellappa, Melanie R McReynolds, Wenyun Lu, Xianfeng Zeng, Mikhail Makarov, Faisal Hayat, Sarmistha Mukherjee, Yashaswini R Bhat, Siddharth R Lingala, Rafaella T Shima, Hélène C Descamps, Timothy Cox, Lixin Ji, Connor Jankowski, Qingwei Chu, Shawn M Davidson, Christoph A Thaiss, Marie E Migaud, Joshua D Rabinowitz, Joseph A Baur
Nicotinamide adenine dinucleotide (NAD) is an essential redox cofactor in mammals and microbes. Here we use isotope tracing to investigate the precursors supporting NAD synthesis in the gut microbiome of mice. We find that dietary NAD precursors are absorbed in the proximal part of the gastrointestinal tract and not available to microbes in the distal gut. Instead, circulating host nicotinamide enters the gut lumen and supports microbial NAD synthesis. The microbiome converts host-derived nicotinamide into nicotinic acid, which is used for NAD synthesis in host tissues and maintains circulating nicotinic acid levels even in the absence of dietary consumption...
December 6, 2022: Cell Metabolism