Fig. 3. Piezo1 is important for swelling-induced insulin secretion.

a [Ca²⁺]_i in INS-1 832/13 cells (measured using Fura-2 fluorescence; F_i) normalized to the basal (F₀) in cells superfused with 2.8 mM glucose before and during exposure to hypotonic solutions (‘hypo’) in the absence (black) or presence (red) of GsMTx4 followed by stimulation with 70 mM K⁺ as indicated. b Average of increase in AUC above basal for hypotonic stimulation with or without GsMTx4 treatment in a (n = 85 and 81 cells for Ctrl and GsMTx4 treatment, respectively, p < 0.0001). c As in a but in control cells (si-Ctrl) and after silencing of Piezo1 (si-Piezo1) superfused as indicated. d As in b but in control cells (si-Ctrl) and after silencing of Piezo1 (si-Piezo1) for c (n = 164 and 156 cells for control and si-Piezo1, respectively, p < 0.0001). e As in a but changes in membrane potential ∆ψ_p measured using PMPI. f Average of increase in AUC above basal for changes in ∆ψ_p induced by the superfusion medium with or without GsMTx4 for e (n = 71 and 62 cells for control and GsMTx4, respectively, p < 0.0001). g Insulin secretion in INS-1 832/13 cells in isotonic (~320 mOsm) or hypotonic buffer (~200 mOsm) with or without GsMTx4 (n = 4) as indicated, p values for the comparison between isotonic and hypotonic stimulation without/with GsMTx4 treatment are 0.0003, 0.7647, respectively, p value for the comparison between hypotonic stimulation without/with GsMTx4 is 0.0002. h Insulin secretion in INS-1 832/13 cells under shear stress (ss) with or without GsMTx4 in isotonic 2.8 mM glucose secretion buffer (n = 8), p values for the comparison between Ctrl and ss without/with GsMTx4 treatment are 0.0095, 0.0075, respectively. Data are presented as box Tukey plot in figures b, d, and f. In g and h, dot plots of individual experiments with mean values ± SEM are shown. The definition of box Tukey is as indicated as in Fig. 1. Evaluation of statistical significance was done using unpaired two-tailed Student’s t-test in figure b, d, and f, two-way ANOVA multiple comparisons in g. In h, statistical significances were evaluated by one-way ANOVA multiple comparisons. *, the significance compared between 2.8 mM and 16.7 mM glucose, #, the significance compared between treatments with and without pharmacological drugs. All statistical tests used were two-sided unless otherwise indicated. **p < 0.01, ***p < 0.001, ****p < 0.0001, ^###p < 0.001.