Research Paper Volume 1, Issue 4 pp 425—437

Figure 5. Mice deficient in Atg7 expression within pancreatic β cells demonstrate altered mitochondria. (A) Western blot analysis of purified pancreatic islets obtained from Atg7^F/+:Rip2-CRE or Atg7^F/F:Rip2-CRE mice demonstrating the relative expression of Atg7, p62 and actin (loading control). (B) Intracellular insulin levels (mean +/- SEM) in pancreatic tissue of 8-9 week old Atg7^F/+:Rip2-Cre (n=4 mice) or Atg7^F/F:Rip2-Cre mice (n=5 mice). The slight reduction in insulin levels in the Atg7^F/F:Rip2-Cre mice was not significant when compared to the control. (C) Pancreatic sections of control Atg7^F/+:Rip2-Cre or Atg7^F/F:Rip2-Cre mice were stained for non-β cell components within the islets with the simultaneous use of anti-glucagon, anti-somatostatin, and anti-polypeptide antibodies. (D) Serial sections were used to visualize β cells with an anti-insulin antibody. Eight week old mice lacking autophagy in β cells have qualitatively similar levels of α, δ, and polypeptide producing cells within their islets, as well as similar levels of β cells when compared to control mice. (E) Electron micrographs demonstrating the accumulation of swollen, dysmorphic mitochondria within the Atg7-deficient β cells. (F) Isolated islets from control and Atg7^-/- mice were assessed for fold +/- SEM changes in basal respiration (Atg7^F/+:Rip2-Cre isolated islets=1), and for oxygen consumption in the presence of oligomycin (0.5 μM) or FCCP (0.5 μM). Results are normalized to islet protein concentration and are from n=4 mice per genotype. (G) Impaired glucose tolerance in Atg7^F/F:Rip2-Cre mice. Blood glucose measurements were made in 8-10 week-old control mice Atg7^F/+:Rip2-Cre (n=10 mice) or Atg7^F/F:Rip2-Cre mice (n=8 mice) following the IP injection of D-glucose (1 g/kg). Data represent the mean +/- SEM. *p≤0.05; **p≤0.01.