Mechanism of RPE Cell Death in α-Crystallin Deficient Mice: A Novel and Critical Role for MRP1-Mediated GSH Efflux
Figure 6
Inhibition of MRP1 significantly decreases basal and apoptotic GSH efflux.
GSH efflux in ARPE-19 cells incubated with two MRP1 inhibitors (75 µM MK571 and 5 mM sulfinpyrazone [SP]) for 5 h (A). ARPE-19 cells were transfected with MRP1 siRNA at the indicated concentrations. RNA and protein were extracted 48 h post transfection. MRP1 mRNA and protein expression was significantly (P<0.01 vs scrambled control) decreased when compared to control or scrambled siRNA alone (B,C). GSH release from MRP1-silenced ARPE-19 cells incubated with 150 µM H2O2 for 5 h in serum free medium. A significant decrease (P<0.001 vs scrambled control) in GSH release was observed in 5 h. A decrease in GSH release only in control cells with no additional change in MRP1 inhibited cells was found and H2O2 treatment did not cause any further change (D). LDH release measured in MRP1 inhibited cells was not affected by any treatment (E). Values are mean± SE (n = 3–4). LDH- Lactate dehydrogenase. ** Significantly different from control cells, P<0.01.