Figure 4

H₂O₂ induced cytosolic Ca²⁺ rise by stimulating lysosomal TRPM2. (A, B). Representative traces (A) and data summary (B) showing the cytosolic [Ca²⁺] changes in response to 3 mM H₂O₂ in mASMCs bathed in 2.5 mM Ca²⁺-HBSS. The H₂O₂-induced [Ca²⁺] rise in mASMCs was reduced by lysosome disruption (200 µM GPN) and abolished by TRPM2 KO. (C–E) Representative traces (C, D) and data summary (E) showing the cytosolic [Ca²⁺] changes in response to 3 mM H₂O₂ in mASMCs bathed in 0 mM Ca²⁺-HBSS. The H₂O₂-induced [Ca²⁺] rise in mASMCs was abolished either by lysosome disruption (200 µM GPN) or by TRPM2 KO. (F) Comparison of basal cytosolic Ca²⁺ level in mASMCs from WT and TRPM2 KO mice under 3 h starvation and non-starvation conditions. Values are mean ± SEM (n = 3 including 8–10 cells in each experiment, *P < 0.05, **P < 0.01, ***P < 0.001, ns = not significant). One-way ANOVA was used for statistical test.