Fig. 7: Wisp1 activates Akt in mouse and human pancreatic islets.
From: Wisp1 is a circulating factor that stimulates proliferation of adult mouse and human beta cells
a Determination of Akt activation (Ser473 phosphorylation) by immunoblot analysis in mouse islets incubated with recombinant mouse Wisp1 protein (rmWisp1) at 500 ng/ml for 30 min. Top: representative immunoblot image. Molecular weight markers are shown on the right. Bottom, quantification of Akt activation, expressed relative to control islets (no rmWisp1), given the value of 1 (control, in gray: n = 10; rmWisp1, in blue: n = 11, from five independent experiments). b, c Beta cell proliferation in mouse islets incubated with rmWisp1 protein and Akt inhibitors. b Representative immunofluorescence images showing ki67 staining in green and insulin in purple. Nuclei are marked with Hoechst (blue). c Percentage of beta cells (insulin+) that are ki67+ in islets incubated with rmWisp1protein at 500 ng/ml for 48 h alone (n = 41 islets, blue) or with the Akt inhibitors AZD5363 (n = 21 islets, pink) or Akti (n = 25 islets, yellow), or left untreated (control, gray: n = 39 islets) from three different isolation experiments. d Determination of AKT activation (Ser473 phosphorylation) by immunoblot analysis in human islets incubated with recombinant human WISP1 protein (rhWISP1) at 500 ng/ml for 15 min. Top: representative immunoblot image. Molecular weight markers are shown on the right. Bottom, quantification of AKT activation, expressed relative to control islets (no WISP1), given the value of 1 (control in gray: n = 12; rhWISP1 in blue: n = 7, from 3 donors) e, f Beta cell proliferation in human islets incubated with Wisp1 protein and Akt inhibitors. e Representative immunofluorescence images showing ki67 staining in green and insulin in red. Nuclei are marked with Hoechst (blue). f Percentage of beta cells (ins+) that are ki67+ in human islets incubated with rhWISP1 protein at 500 ng/ml for 48 h alone (n = 21 islets, blue) or with the Akt inhibitors AZD5363 (n = 31 islets, pink) or Akti (n = 15 islets, yellow), or left untreated (control, gray: n = 20 islets) from 3 donors. All data shown represent mean ± SEM for the indicated n. Comparisons were made using two-tailed Student’s t test (a, d) or one-way ANOVA (c, f). *p < 0.05; ***p < 0.001; ****p < 0.0001. Scale bars are 25 μm.
