Fig. 7

Loss of lipid-dependent coordination of Ca²⁺ fluxes across plasma and lysosomal membranes in APOE4 immortalized astrocytes. a Representative traces and quantification of the magnitude of ATP- triggered intracellular Ca²⁺ responses in cells treated with DMSO or with 100 μM Ned 19 for 20 min in KH medium (N = 3). b, c Representative traces and quantification of lysosomal Ca²⁺ content measured as AUC after 200 μM GPN addition to (b) APOE3 and (c) APOE4 astrocytes in KH medium, as compared to DMEM medium supplemented with FBS (FBS) (N = 3) (FBS-related results were presented in Fig. 3); d Representative traces and quantification of Ca²⁺ ER release in 100 μM ATP-stimulated astrocytes transfected with G-CEPIA1er, and kept in KH medium supplemented or not with FBS (N = 4). e, f Representative traces and quantification of purinergic-induced Ca²⁺ responses in (e) APOE3 and (f) APOE4 astrocytes in KH medium supplemented with 10% of FBS with or without Ca²⁺/1 mM EGTA for 10 min, and KH medium with Ca²⁺ or without Ca²⁺/500 μM EGTA for 1 min. g Representative images from Lamp1 immunofluorescence of both cell lines and quantification of the percentage of lysosomes in different ranges of distance, the 0 value being the nucleus in each cell. (N = 3, 30 to 40 cells quantified). Scale bar represents 15 μm. One-way ANOVA was used in sections a, d, e and f, unpaired parametric T-test in b and c, and two-way ANOVA in g. p < 0.05 (*), p < 0.001 (***), p < 0.0001 (****)