Trace amine-associated receptor 1 activation regulates glucose-dependent insulin secretion in pancreatic beta cells in vitro

Abstract

Trace amines are a group of endogenous monoamines which exert their action through a family of G protein-coupled receptors known as trace amine-associated receptors (TAARs). TAAR1 has been reported to regulate insulin secretion from pancreatic beta cells in vitro and in vivo. This study investigates the mechanism(s) by which TAAR1 regulates insulin secretion. The insulin secreting rat INS-1E -cell line was used for the study. Cells were pre-starved (30 minutes) and then incubated with varying concentrations of glucose (2.5 – 20 mM) or KCl (3.6 – 60 mM) for 2 hours in the absence or presence of various concentrations of the selective TAAR1 agonist RO5256390. Secreted insulin per well was quantified using ELISA and normalized to the total protein content of individual cultures. RO5256390 significantly (P < 0.0001) increased glucose-stimulated insulin secretion in a dose-dependent manner, with no effect on KCl-stimulated insulin secretion. Affymetrix-microarray data analysis identified genes (Gnas, Gng7, Gngt1, Gria2, Cacna1e, Kcnj8, and Kcnj11) whose expression was associated with changes in TAAR1 in response to changes in insulin secretion in pancreatic beta cell function. The identified potential links to TAAR1 supports the regulation of glucose-stimulated insulin secretion through KATP ion channels.