NAD metabolism fuels human and mouse intestinal inflammation.

1. Gut. 2018 Oct;67(10):1813-1823. doi: 10.1136/gutjnl-2017-314241. Epub 2017 Sep 6. NAD metabolism fuels human and mouse intestinal inflammation. Gerner RR(1)(2), Klepsch V(3), Macheiner S(1)(2), Arnhard K(4), Adolph TE(1), Grander C(1), Wieser V(1), Pfister A(1)(2), Moser P(5), Hermann-Kleiter N(3), Baier G, Oberacher H(4), Tilg H(1), Moschen AR(1)(2). Author information: (1)Division of Internal Medicine I, Department of Medicine, Medical University Innsbruck, Innsbruck, Austria. (2)Christian Doppler Laboratory for Mucosal Immunology, Medical University Innsbruck, Innsbruck, Austria. (3)Division of Translational Cell Genetics, Department for Pharmacology and Genetics, Medical University Innsbruck, Innsbruck, Austria. (4)Institute of Legal Medicine and Core Facility Metabolomics, Medical University Innsbruck, Innsbruck, Austria. (5)Department of Pathology, Medical University Innsbruck, Innsbruck, Austria. OBJECTIVE: Nicotinamide phosphoribosyltransferase (NAMPT, also referred to as pre-B cell colony-enhancing factor or visfatin) is critically required for the maintenance of cellular nicotinamide adenine dinucleotide (NAD) supply catalysing the rate-limiting step of the NAD salvage pathway. NAMPT is strongly upregulated in inflammation including IBD and counteracts an increased cellular NAD turnover mediated by NAD-depleting enzymes. These constitute an important mechanistic link between inflammatory, metabolic and transcriptional pathways and NAD metabolism. DESIGN: We investigated the impact of NAMPT inhibition by the small-molecule inhibitor FK866 in the dextran sulfate sodium (DSS) model of colitis and the azoxymethane/DSS model of colitis-associated cancer. The impact of NAD depletion on differentiation of mouse and human primary monocytes/macrophages was studied in vitro. Finally, we tested the efficacy of FK866 compared with dexamethasone and infliximab in lamina propria mononuclear cells (LPMNC) isolated from patients with IBD. RESULTS: FK866 ameliorated DSS-induced colitis and suppressed inflammation-associated tumorigenesis in mice. FK866 potently inhibited NAMPT activity as demonstrated by reduced mucosal NAD, resulting in reduced abundances and activities of NAD-dependent enzymes including PARP1, Sirt6 and CD38, reduced nuclear factor kappa B activation, and decreased cellular infiltration by inflammatory monocytes, macrophages and activated T cells. Remarkably, FK866 effectively supressed cytokine release from LPMNCs of patients with IBD. As FK866 was also effective in Rag1-⁄- mice, we mechanistically linked FK866 treatment with altered monocyte/macrophage biology and skewed macrophage polarisation by reducing CD86, CD38, MHC-II and interleukin (IL)-6 and promoting CD206, Egr2 and IL-10. CONCLUSION: Our data emphasise the importance of NAD immunometabolism for mucosal immunity and highlight FK866-mediated NAMPT blockade as a promising therapeutic approach in acute intestinal inflammation. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted. DOI: 10.1136/gutjnl-2017-314241 PMCID: PMC6145287 PMID: 28877980 [Indexed for MEDLINE] Conflict of interest statement: Competing interests: None declared.