[HTML][HTML] β cell GHS-R regulates insulin secretion and sensitivity

G Pradhan, CS Wu, D Villarreal, JH Lee… - International Journal of …, 2021 - mdpi.com
G Pradhan, CS Wu, D Villarreal, JH Lee, HW Han, A Gaharwar, Y Tian, W Fu, S Guo
International Journal of Molecular Sciences, 2021mdpi.com
Growth hormone secretagogue receptor (GHS-R) is widely known to regulate food intake
and adiposity, but its role in glucose homeostasis is unclear. In this study, we investigated
the expression of GHS-R in mouse pancreatic islets and its role in glycemic regulation. We
used Ghsr-IRES-tauGFP mice, with Green Fluorescent Protein (GFP) as a surrogate for GHS-
R, to demonstrate the GFP co-localization with insulin and glucagon expression in
pancreatic islets, confirming GHS-R expression in β and α cells. We then generated β-cell …
Growth hormone secretagogue receptor (GHS-R) is widely known to regulate food intake and adiposity, but its role in glucose homeostasis is unclear. In this study, we investigated the expression of GHS-R in mouse pancreatic islets and its role in glycemic regulation. We used Ghsr-IRES-tauGFP mice, with Green Fluorescent Protein (GFP) as a surrogate for GHS-R, to demonstrate the GFP co-localization with insulin and glucagon expression in pancreatic islets, confirming GHS-R expression in β and α cells. We then generated β-cell-specific GHSR-deleted mice with MIP-Cre/ERT and validated that GHS-R suppression was restricted to the pancreatic islets. MIP-Cre/ERT;Ghsrf/f mice showed normal energy homeostasis with similar body weight, body composition, and indirect calorimetry profile. Interestingly, MIP-Cre/ERT;Ghsrf/f mice exhibited an impressive phenotype in glucose homeostasis. Compared to controls, MIP-Cre/ERT;Ghsrf/f mice showed lower fasting blood glucose and insulin; reduced first-phase insulin secretion during a glucose tolerance test (GTT) and glucose-stimulated insulin secretion (GSIS) test in vivo. The isolated pancreatic islets of MIP-Cre/ERT;Ghsrf/f mice also showed reduced insulin secretion during GSIS ex vivo. Further, MIP-Cre/ERT;Ghsrf/f mice exhibited improved insulin sensitivity during insulin tolerance tests (ITT). Overall, our results confirmed GHS-R expression in pancreatic β and α cells; GHS-R cell-autonomously regulated GSIS and modulated systemic insulin sensitivity. In conclusion, β cell GHS-R was an important regulator of glucose homeostasis, and GHS-R antagonists may have therapeutic potential for Type 2 Diabetes.
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