Whole-Body Loss of NUCB2/Nesfatin-1 Alters Enteric Hormone Expression

Abstract

Objectives: Post-prandial insulin secretion is predominantly regulated by four intestinal hormones: glucagon-like peptide 1 (GLP-1), glucose-dependent insulinotropic polypeptide (GIP) [collectively called incretins], Cholecystokinin (CCK) and peptide YY (PYY). Nesfatin-1, an insulinotropic and anorexigenic secreted peptide encoded by nucleobindin-2 (NUCB2) was reported in the mouse hypothalamus. We have earlier reported that nesfatin-1 stimulates incretins and CCK expression and secretion while being a potent inhibitor of PYY expression, both in vitro and vivo. We further this observation in this abstract by testing the incretin, CCK, and PYY expression in a mouse model of global Nesfatin-1/NUCB2 knockout (NKO). Methods: For the current study 6-8 weeks old male NKO mice and age-matched littermate C57BL/6J mice were used as controls (n=7). Total RNA extraction followed by Real-Time quantitative PCR (RT-qPCR) of small/large intestine samples was carried out. One-way ANOVA followed by Tukey’s multiple comparison test using GraphPad Prism software was used for data analysis. p<0.01 was considered statistically significant. Results: We found that whole-body knockout of NUCB2/Nesfatin-1 downregulated large and small intestinal expression of incretins, CCK, and increased expression of PYY. Conclusion: The current data extends our earlier observation in a mouse model lacking nesfatin-1. Lack of nesfatin-1 affects the healthy expression of incretins, CCK, and PYY in the intestine. These results highlight the importance of endogenous nesfatin-1 and its role in energy balance by modulating crucial enteroendocrine hormones known for their role in energy balance. Source of Support: Dr. Unniappan's lab (University of Saskatchewan) and Canadian Institutes of Health Research (CIHR).