Activation of the p62/Keap1/Nrf2 Pathway Protects Against Ferroptosis in Cerebral Ischemia-Reperfusion Injury.

BACKGROUND

Protein p62 interacts with Kelch-like ECH-associated protein 1 (Keap1) competitively, triggering the oxidative stress response mediated by NF-E2-related factor 2 (Nrf2) and preventing ferroptosis in SH-SY5Y cells. Emerging evidence implicates that this regulatory axis may confer neuroprotection against cerebral ischemia-reperfusion injury (CIRI). The current investigation was designed to elucidate whether the p62/Keap1/Nrf2 signaling pathway contributes to the amelioration of CIRI through modulation of ferroptosis.

METHODS

In SH-SY5Y cells, we used an oxygen-glucose deprivation/reperfusion (OGD/R) paradigm. In Sprague-Dawley rats, we used a middle cerebral artery occlusion/reperfusion (MCAO/R) model. Through these models, we investigated the effects of p62/Keap1/Nrf2 pathway activation. Additionally, we used in vitro experiments to analyze ferroptosis markers, cell damage, and the expression of pathway proteins. We injected the p62-overexpressing lentivirus into SH-SY5Y cells and the lateral ventricle of rats subjected to MCAO/R. Finally, we investigated the effects of an Nrf2 activator and a ferroptosis inhibitor.

RESULTS

Nrf2 negatively regulated OGD/R-triggered ferroptosis in SH-SY5Y cells by increasing glutathione peroxidase 4 (GPX4) expression and decreasing acyl-CoA synthetase long-chain family member 4 (ACSL4) levels. p62 overexpression in cells enhanced the interaction between Keap1 and p62, activating Nrf2 and protecting against OGD/R-triggered ferroptosis. Activating the p62/Keap1/Nrf2 signaling pathway in vivo reduced the brain injury area, decreased neuromotor functional impairment, and decreased the expression of ferroptosis markers in rats.

CONCLUSIONS

Activation of the p62/Keap1/Nrf2 signaling pathway reduces ferroptosis and alleviates CIRI. This protective mechanism provides novel directions for investigating the pathological mechanisms of CIRI.