G protein-coupled receptors (GPCRs) in the gastrointestinal tract are involved in maintaining glucose and energy homeostasis by regulating the release of gut hormones in response to luminal dietary nutrients as well as microbial metabolites. We recently identified that an orphan GPCR, Gpr17, was co-expressed in glucagon-like peptide-1 (GLP-1) -expressing EECs in human and rodent intestinal epithelium. However, it is unknown how Gpr17 ablation in the intestinal epithelium affects feeding behavior and satiety regulation. To address this question, we used genetic knockout approach to generate intestinal Gpr17-deficient mice and analyzed their glucose metabolism and feeding behavior. We showed that intestinal Gpr17-deficient mice had similar growth curve, body composition, and ad libitum food intake compared with littermate controls. We found that acute genetic ablation of Gpr17 in intestinal epithelium (iKO) improved oral glucose tolerance and glucose-stimulated insulin secretion (GSIS) in female and male mice. iKO mice responded to glucose or lipid ingestion with increased secretion of GLP-1, but not the other incretin glucose-dependent insulinotropic polypeptide (GIP) . Intestinal Gpr17-deficient mice responded to fasting-refeeding challenge with reduced fasting locomotor activity and less food intake after refeeding, suggesting increased satiety during the phase of rebound hyperphagia. Furthermore, comprehensive studies including gut morphology, gut epithelium heterogeneity by scRNA-seq, and microbiome analysis were examined but none of them was changed because of intestinal Gpr17 ablation. In addition, male Gpr17 whole body knockout mice have improved intraperitoneal glucose tolerance, and increased insulin sensitivity in hyperinsulinemic-euglycemic clamp studies.
In conclusion, our work showed that ablation of intestinal Gpr17 signaling led to improved neurohormonal regulation to maintain metabolic homeostasis.
National Institute of Health (R01DK120772)