Figure 4

Hyper-responsiveness to ATP increased intracellular Ca^{2 +}signal during APAP challenge. (A) Ca²⁺ signal induced by ATP and ADP (10 μM) in HepG2 cells. (B-C) Culture medium from necrotic/suffering cells triggered intracellular Ca²⁺ signal in “naïve” HepG2 cells, which was abolished by apyrase (10 U/ml) or P2 blocker suramin (0.1 mM). (D-E) Snapshots from confocal microscopy showing Ca²⁺ signal in HepG2 cells treated or not with APAP at 20 mM. (F-G) ATP-triggered Ca²⁺ signals from cells incubated or not with APAP for 24 hours. (H) Ca²⁺ sequestration by BAPTA-AM (1 nM) partially reverted APAP-mediated cell death. * P < 0.05 in comparison to control group and ** in comparison to vehicle or medium treated group.