Fig. 7: Differences in PDX1 and MAFA levels are encoded by islet signaling patterns.
From: PDX1LOW MAFALOW β-cells contribute to islet function and insulin release
a–c Islet dissociation (B-NORM DISS.) leads to loss of β-cells in the bottom 15 percentile for PDX1 (a) and MAFA (b), also shown by representative images (c) (B-NORM data are superimposed for comparison) (n = 6 islets/4 animals; two-way ANOVA, Bonferroni’s multiple comparison) (PDX1: F = 7.23, DF = 19) (MAFA: F = 4.69, DF = 20) (scale bar = 42.5 µm). d PDX1LOW β-cells are present 3 h following islet dissociation (n = 80 islets/10 coverslips; two-way ANOVA; Bonferonni’s multiple comparison test) (PDX1: F = 9.54, DF = 40) (MAFA: F = 5.22, DF = 20). e, f shGjd2 decreases Gjd2 expression (e) (n = 5 animals; paired t-test), but this does not alter the proportion of PDX1LOW β-cells (f) (n = 8 islets/2 animals; two-way ANOVA, Bonferroni’s multiple comparison) (F = 12.85, DF = 20). g–i h4MDi is expressed at the β-cell membrane (g) (n = 3 islets) (scale bar = 85 µm), allowing silencing of Ca2+ activity in D-MAT but not D-NORM (control) islets (h, i) (n = 7 islets/3 animals; paired t-test). j 3 h CNO incubation decreases Ca2+ levels in D-MAT islets (vehicle, DMSO) (n = 16 islets/5 animals; Mann-Whitney U-test). k, l CNO decreases Ca2+ oscillation frequency (k) in D-MAT islets, also shown by traces (l) (n = 6 islets/2 animals; unpaired t-test). m–o 48 h CNO incubation induces β-cell loss in the bottom 15 percentile for PDX1 (m) and MAFA (n) in D-MAT islets, also shown by representative images (o) (n = 8 islets/3 animals; two-way ANOVA, Bonferroni’s multiple comparison) (PDX1: F = 5.34, DF = 20) (MAFA: F = 4.63, DF = 20) (scale bar = 60 µm). p 2 h washout restores Ca2+ levels in CNO-treated islets (n = 21 islets/3 animals; unpaired t-test). q, r Ca2+ traces (q) showing blunted responses to 11 mM glucose (G11) and KCl (10 mM) (r) in D-MAT islets (following CNO washout) (n = 21 islets/3 animals; unpaired t-test). s, t D-MAT islets display decreases in β-cell–β-cell connectivity (s), associated with hub loss (red circles) (t) (n = 7 islets/4 animals; Mann Whitney U-test). u Schematic showing effects of altering Ca2+ signaling patterns. Bar graphs and traces show the mean ± SEM. Box-and-whiskers plot shows median and min-max. All tests are two-sided where relevant.
