Stable overexpression of DJ-1 protects H9c2 cells against oxidative stress under a hypoxia condition.

It has been well accepted that increased reactive oxygen species (ROS) and the subsequent oxidative stress is one of the major causes of ischemia/reperfusion (I/R) injury. DJ-1 protein, as a multifunctional intracellular protein, plays an important role in regulating cell survival and antioxidant stress. Here, we wondered whether DJ-1 overexpression attenuates simulated ischemia/reperfusion (sI/R)-induced oxidative stress. A rat cDNA encoding DJ-1 was inserted into a mammalian expression vector. After introduction of this construct into H9c2 myocytes, stable clones were obtained. Western blot analysis of the derived clones showed a 2.6-fold increase in DJ-1 protein expressing. Subsequently, the DJ-1 gene-transfected and control H9c2 cells were subjected to sI/R, and then cell viability, lactate dehydrogenase, malondialdehyde, intracellular ROS and antioxidant enzymes (superoxide dismutase, catalase and glutathione peroxidase) were measured appropriately. The results showed that stable overexpression of DJ-1 efficiently attenuated sI/R-induced viability loss and lactate dehydrogenase leakage. Additionally, stable overexpression of DJ-1 inhibited sI/R-induced the elevation of ROS and MDA contents followed by the increase of antioxidant enzymes (superoxide dismutase, catalase and glutathione peroxidase) activities and expression. Our data indicate that overexpression of DJ-1 attenuates ROS generation, enhances the cellular antioxidant capacity and prevents sI/R-induced oxidative stress, revealing a novel mechanism of cardioprotection. Importantly, DJ-1 overexpression may be an important part of a protective strategy against ischemia/reperfusion injury.