Fig. 3

Enhanced Ca²⁺ signals in immortalized astrocytes from APOE4 vs APOE3 targeted replacement mice. Ca²⁺ responses measured using fura-2/AM in APOE3 and APOE4 astrocytes after stimulation with (a) 100 μM ATP, (b) 10 μM noradrenaline (NA), and (c) 100 μM acetylcholine (Ach). Representative traces and quantification of the magnitude of the responses are shown (N = 4 for a and c, and N = 3 for b). d Images of astrocytes transfected with the Ca²⁺ probes for mitochondria (CEPIA3mt) and ER (G-CEPIA1er). Scale bar represents 15 μm. e Representative traces and quantification of mitochondrial Ca²⁺ in APOE3 and APOE4 cells transfected with CEPIA3mt upon stimulation with ATP (N = 3). f Representative traces and quantification of the decrease in ER Ca²⁺ upon stimulation of purinergic receptors in APOE3 and APOE4 cells transfected with GCEPIA1er (N = 5). Unpaired parametric T-test was used to compare responses in APOE3 vs APOE4 astrocytes. p < 0.05 (*), p < 0.01 (**), p < 0.001 (***)