Figure 6

Figure 6

STAT3 plays an important role in high amino acid induced α cell proliferation.A–C, representative images (A) and quantification (B and C) of total STAT3/α-tubulin and p-STAT3/STAT3 levels in WT and ErbB3 KO αTC1-6 cells cultured in control or high amino acids medium, the relative protein level was analyzed using one-way ANOVA with a Bonferroni post hoc test. Data are presented as mean ± SD. ∗∗p < 0.01 and ∗∗∗∗p < 0.0001. D and E, representative immunofluorescence images (D) and quantification (E) of islets transduced by sh-ErbB3 or control adenovirus and cultured in control or glutamine plus alanine contained medium, white arrowheads indicate representative p-STAT3–positive α cells (n = 3–7), and the p-STAT3–positive α cells ratio was analyzed using two-way ANOVA with a Bonferroni post hoc test. Data are presented as mean ± SD. ∗∗p < 0.01. F and G, representative immunofluorescence images of p-STAT3 (F) and quantification (G) of the percentage of p-STAT3–positive α cells in pancreatic islets of WT and Gcgr^−/− mice (n = 8–15), and the p-STAT3–positive α cell ratio was analyzed using unpaired two-tailed t test. Data are presented as mean ± SD. ∗∗∗∗p < 0.0001. H and I, representative immunofluorescence images (H) and quantification (I) of islets cultured in the control medium or medium supplemented with glutamine and alanine in the presence of 1 μM Stattic or vehicle (n = 7–11), the Ki67-positive α cells ratio was analyzed using two-way ANOVA with a Bonferroni post hoc test. Data are presented as mean ± SD. ∗∗∗∗p < 0.0001. White arrowheads indicate representative Ki67-positive α cells. J and K, representative single optical section of islet immunofluorescence images (J) and quantification (K) of islets cultured in control medium or medium supplemented with glutamine and alanine in the presence of 30 nM rapamycin or vehicle (n = 6–10). White arrowheads indicate representative p-STAT3–positive α cells. The p-STAT3–positive α cells ratio was analyzed using two-way ANOVA with a Bonferroni post hoc test. Data are presented as mean ± SD. ∗ p < 0.05, ∗∗∗∗p < 0.0001. GCGR, glucagon receptor; STAT3, signal transducer and activator of transcription 3.