QPRT and colitis: To verify the impact of hepatic NAD+ metabolism on the progression of colitis, we disrupted NAD+ metabolism specifically in the liver by knockdown of QPRT using AAV2/8‐TBG‐mir30‐m‐Qprt‐ZsGreen (Qprt‐KD), which successfully decrease the liver NAD+, plasma NAM and intestinal NAD+ levels, which was rescued by NMN (Figure 2I; Figure S3I,J, Supporting Information).