Fig. 1: Increased α/β cell ratio in βRapKO^GFP mice.

a Heatmap of genes critical to endocrine cell in wild type (WT) and βRapKO islets (n = 4–5). b The number of Ins⁺ cells per islet (n = 3, p = 0.0008) and c the number of Gcg⁺ cells per islet were calculated (n = 3, p = 0.023). At least, 46 islets were used for quantifications. d The proportion of pancreatic α-cell mass among pancreatic α- and β-cell mass was shown (n = 4, p = 0.0017). e The proliferation of Gcg⁺ cell was determined by quantification of the percentage of Ki67⁺ cells in Gcg⁺ cells (n = 3). At least, 50 islets were used for quantifications. f Pancreatic sections from 8-week-old WT, βRapKO^GFP mice were immunostained for insulin (white), glucagon (green), and GFP (red). Nuclei were stained with DAPI (blue) (n = 3). The yellow arrows indicated insulin, glucagon, and GFP co-stained cells. Scale bars, 20 μm. g The percentage of GFP⁺Gcg⁺ cells among GFP⁺ cells in 8-week-old WT and βRapKO^GFP mice (n = 3, p = 1.83046E-05). At least, 1837 GFP⁺ cells over three mice each group were used for quantifications. h Representative pancreatic sections showed expression of α-cells marker—Arx (red), insulin (white), and glucagon (green) in WT and βRapKO^GFP mice at 8 weeks of age (n = 3). Scale bars, 20 μm. i Immunostaining showed expression of α-cells marker—MafB (red), insulin (white), and glucagon (green) in control and βRapKO^GFP mice at 8 weeks of age (n = 3). Yellow boxes showed the specific areas of the islet, which were enlarged and represented by arrows on the right to demonstrate protein expression within specific cells. Scale bars, 20 μm. j Transmission electron microscopy (TEM) of pancreatic islets reveals a combination of mature insulin, immature insulin, and glucagon-like granules in the same cell in βRapKO^GFP mice (n = 3 independent samples). Granule identity is indicated by colored arrows: glucagon (red), mature insulin (blue), and immature insulin (yellow). Data represent means ± SEM. *p < 0.05, **p < 0.01, ***p < 0.001 by two-sided Student’s t-test.