Fig. 9.

TRPM2-S-expressing cells are more susceptible to H₂O₂-induced cell death. SH-SY5Y cells stably transfected with empty vector, TRPM2-L, or TRPM2-S were treated with 50 or 100 μM H₂O₂ for 6 h (A and C) or 24 h (B and D). A and B: cell viability determined by XTT assay. Values are means ± SE of 2 experiments done in triplicate at 6 h and 4 experiments at 24 h. *P ≤ 0.05. C and D: cell death confirmed by examining cleavage (Clvd) of poly(ADP-ribose) polymerase (PARP) and caspase-3 on Western blots. V, L, and S in C and D were probed at the same time, and spaces indicate where treatment with 1,000 μM H₂O₂ was removed because of poor viability. Western blotting was done on all experiments in A and B, and representative Western blots are shown in C and D. In D, light exposure shows reduced uncleaved PARP in S compared with V and L. E: Western blots from membrane fractionation of lysates of cells treated with H₂O₂ for 24 h were probed with anti-Glut1 or anti-Na⁺-K⁺-ATPase. Representative results of 2 experiments are shown. After exposure to H₂O₂, membrane Glut1 was decreased in TRPM2-S-expressing cells but increased in TRPM2-L-expressing cells.