Fig. 5.

A reduced cytosolic NADH/NAD⁺ redox state suppresses Raptinal-induced apoptosis by inhibiting JNK activation. a HepG2 cells were pre-incubated for 1 h and clamped in media with different L/P ratios after which vehicle (0.1% DMSO) or 10 µM Raptinal was added for 2 h. Whole lysates were prepared and immunoblotted for p-JNK, and p-Bax. Shown is a representative experiment of N = 3. b HepG2 cells were pre-incubated for 1 h with the JNK inhibitor SP600125 under oxidizing redox clamp (L/P = 1). Subsequently, vehicle (0.1% DMSO) or 10 µM Raptinal was added for 1.5 h. At the end of the incubation, caspase 3/7 was measured. Data are normalized to vehicle in absence of SP600125 and shown are the mean ± SD of a representative experiment of N = 2. Statistical significance was tested with a two-way ANOVA with multiple comparison (Tukey) with ****p < 0.0001, **p < 0.01. c Treatment as in (b) but for 2 h with vehicle (0.1% DMSO) or 10 µM Raptinal in the presence and absence of SP600125. At the end of incubation, cells were harvested and immunoblotted for p-JNK, p-Bax, and PARP-1. Shown is a representative experiment of N = 2