Fig. 1: Expression of GPR116 and structurally related aGPCRs in pancreatic islet cells.

a Pancreatic islet RNAseq analysis¹⁶ was re-analyzed to determine the expression of aGPCRs. Here, we observe high expression of aGPCRs with an already described function in islets such as Gpr56 or Lphn1. Among the highly expressed receptors we also detected Gpr116. Given is the mean ± SD of 10 animals. b qPCR analysis was performed to confirm high expression of Gpr116 in pancreatic islets. Furthermore, we also detected expression in specific cell lines mimicking delta (QGP-1), alpha (αTC1-9) and beta (MIN6, INS-1) cells. Given is the relative expression of GPR116 normalized to β-actin as reference gene as mean ± SEM of 2 (INS-1, MIN6), 3 (QGP-1, αTC1-9), or 9 (islets) independent experiments carried out in triplicates. Statistical differences in expression were determined in the cell lines αTC1-9, MIN6, and INS-1 in comparison to QGP-1 cells using Student’s t test (*P ≤ 0.05; **P ≤ 0.01). c–e To detect cell-type specific expression of Gpr116 mRNA in situ hybridization studies combined with immunofluorescence was performed on sections of mouse pancreas. Probes for Gpr116 (red) and somatostatin (white) as well as Gpr116 (red) and Cd34 (green) showed a partially overlapping expression (c), while Gpr116 mRNA was hardly detected in insulin- (d), or glucagon-positive (e) cells shown in green.