SIRT6 and colitis: reported that that inhibition of NAMPT via the small-molecule inhibitor FK866 effectively reduces NAD+ levels within the intestinal epithelium and ameliorates DSS-induced colitis by decreasing the expression of mucosal NAD+-consuming enzymes, including PARP1 and SIRT6, and reducing the mucosal immune cell infiltration and release of proinflammatory cytokines and chemokines (53).