Tat-DJ-1 enhances cell survival by inhibition of oxidative stress, NF-κB and MAPK activation in HepG2 cells

Objectives To identify the protective effect of DJ-1 protein against oxidative stress-induced HepG2 cell death, we used cell-permeable wild type (WT) and a mutant (C106A Tat-DJ-1) protein. Results By using western blotting and fluorescence microscopy, we observed WT and C106A Tat-DJ-1 proteins were efficiently transduced into HepG2 cells. Transduced WT Tat-DJ-1 proteins increased cell survival and protected against DNA fragmentation and intracellular ROS generation levels in H2O2-exposed HepG2 cells. At the same time, transduced WT Tat-DJ-1 protein significantly inhibited NF-kappa B and MAPK (JNK and p38) activation as well as regulated the Bcl-2 and Bax expression levels. However, C106A Tat-DJ-1 protein did not show any protective effect against cell death responses in H2O2-exposed HepG2 cells. Conclusions Oxidative stress-induced HepG2 cell death was significantly reduced by transduced WT Tat-DJ-1 protein, not by C106A Tat-DJ-1 protein. Thus, transduction of WT Tat-DJ-1 protein could be a novel strategy for promoting cell survival in situations of oxidative stress-induced HepG2 cell death.