Iduna protects HT22 cells from hydrogen peroxide-induced oxidative stress through interfering poly(ADP-ribose) polymerase-1-induced cell death (parthanatos)

Oxidative stress-induced cell death is common in many neurological diseases. However, the role of poly(ADP-ribose) polymerase-1-induced cell death (parthanatos) has not been fully elucidated. Here, we found that hydrogen peroxide (H₂O₂) could lead to PARP-1 activation and apoptosis-inducing factor nuclear translocation in a concentration dependent manner. Iduna, as a novel regulator of parthanatos, was also induced by H₂O₂. Down-regulation of Iduna by genetic ablation promoted H₂O₂-induced cell damage. Up-regulation of Iduna reduced the loss of mitochondrial potential and ATP and NAD + production, but did not affect the mitochondrial dysfunction-induced cytochrome c release, increase of Bax/Bcl-2 ratio, and Caspase-9/Caspase-3 activity. In contrast, overexpression of Iduna inhibited activation of PARP-1 and nuclear translocation of AIF. Further study showed that PARP-1 specific inhibitor, DPQ, blocked the protective effect of Iduna against H₂O₂-induced oxidative stress. Moreover, in the presence of proteasome inhibitor (MG-132) or ubiquitin E1 inhibitor (PYR-41), protective effect of Iduna was significantly weaken. These results indicate that Iduna acts as a potential antioxidant by improving mitochondrial function and inhibiting oxidative stress-induced parthanatos, and these protective effects are dependent on the involvement of ubiquitin–proteasome system.