Fig. 5: Dysfunction of cytosolic calcium in Gal3-treated MIN6 cells and mouse islets.

a Typical traces of time-lapse calcium imaging via fluo-4, AM (1 μM) in MIN6 cells with high glucose (16.8 mM) stimulation and Gal3 (80 ng/ml, 6 h) treatment. n = 33 cells in vehicle group, and n = 26 cells in Gal3 group. b Frequency of cytosolic calcium spikes of (a). c–e Cytosolic calcium dynamics (c), frequency of cytosolic calcium spikes (d) and peak value of cytosolic calcium transient (e) stimulated by high glucose (16.8 mM) in different β cells of Ins1-GCaMP6f mouse islets with or without Gal3 (250 ng/ml, 6 h) treatment. Scale bar, 10 μm. n = 4 biologically independent samples (12-week-old NC-fed mice, c–e). f, g The ratios of fluorescence signals (f) and distribution analysis of concentrations of cytosolic free Ca²⁺ ([Ca²⁺]i) (g) by fura-2, AM (2 μM) at 340 nm and 380 nm in MIN6 cells with basal glucose (2.8 mM) and Gal3 (80 ng/ml, 6 h) treatment. n = 222 cells in vehicle group, and n = 232 cells in Gal3 group. h Diagram of patch clamp experiment, created with BioRender.com. i, j Ca²⁺ currents records in MIN6 cells without Gal3 and sequentially given Gal3 (80 ng/ml, 5 min) (n = 4 biologically independent cell samples). k Ca²⁺ currents records in MIN6 cells without Gal3 and sequentially given Gal3 (80 ng/ml, 5 min) and then given vehicle buffer washout. Data were analyzed by two-sided Student’s t-test without adjustments for multiple comparisons. All data are presented as the mean ± SEM. Source data are provided as Source Data file.