Evidence of Nesfatin-1 in Mouse Intestinal Enteroendocrine Cells

Abstract

Objectives: Post-prandial insulin secretion is predominantly regulated by four intestinal hormones: glucagon-like peptide 1 (GLP-1), glucose-dependent insulinotropic polypeptide (GIP), Cholecystokinin (CCK) and peptide YY (PYY). Nesfatin-1, an insulinotropic and anorexigenic secreted peptide was reported in mouse hypothalamus. Data supporting nesfatin-1 expression in intestine is minimal. Is nesfatin-1 expressed in mouse intestinal cells? Does it affect intestinal hormones known to stimulate or inhibit insulin secretion? We present STC-1 cells as viable in vitro models to study nesfatin-1’s biological action in intestine. Methods: Immunofluorescence histochemistry (IHC) of intestinal sections from male C57BL/6 mice were carried out. STC-1 cells (n=8 wells/treatment) were dose-dependently treated with nesfatin-1, followed by RT-qPCR and immunoassay (ELISA) respectively. 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: IHC showed NUCB2/nesfatin-1 co-localizing CCK, PYY and GLP-1 in the intestinal mucosa of mice. Static incubation of STC-1 cells with nesfatin-1 upregulated both CCK, PYY and GLP-1 mRNA expression (1 and 10nM) and secretion at 1 hr post-incubation (0.1, 1 and 10nM). Conversely, nesfatin-1 downregulated PYY mRNA expression and secretion in STC-1 cells (all doses tested). Conclusion: The current data shows cell-specific localization of nesfatin-1 in the intestinal mucosa and establishes STC-1 cells as in vitro models to study nesfatin-1. This study adds a novel function for intestinal nesfatin-1 in stimulating insulinotropic intestinal hormones (GLP-1, GIP, CCK) and inhibit PYY which is insulinostatic.