QPRT knockdown enhances inflammation, while NAD + precursor supplementation (e.g. nicotinamide riboside [NR]) restores cellular energy and reduces inflammation in vitro and in dextran sodium sulfate (DSS)-induced colitis.<h4>Conclusion</h4>A metabolic bottleneck at QPRT prevents efficient NAD+ synthesis from Trp in IBD, sustaining inflammation. This evidence concerns the gene QPRT and colitis.