SCGN deficiency results in colitis susceptibility

Abstract

Inflammatory bowel disease (IBD) affects 1.5-3.0 million people in the United States. IBD is genetically determined and many common risk alleles have been identified. Yet, a large proportion of genetic predisposition remains unexplained. In this study, we report the identification of an ultr arare missense variant (NM_006998.3:c.230G > A;p.Arg77His) in the <i>SCGN</i> gene causing Mendelian early-onset ulcerative colitis. <i>SCGN</i> encodes a calcium sensor that is exclusively expressed in neuroendocrine lineages, including enteroendocrine cells and gut neurons. SCGN interacts with the SNARE complex, which is required for vesicle fusion with the plasma membrane. We show that the <i>SCGN</i> mutation identified impacted the localization of the SNARE complex partner, SNAP25, leading to impaired hormone release. Finally, we show that mouse models of <i>Scgn</i> deficiency recapitulate impaired hormone release and susceptibility to DSS-induced colitis. Altogether, these studies demonstrate that functional deficiency in SCGN can result in intestinal inflammation and implicates the neuroendocrine cellular compartment in IBD.