ATG5 Knockdown Attenuates Ischemia‒Reperfusion Injury by Reducing Excessive Autophagy-Induced Ferroptosis

Autophagy has been described to be both protective and pathogenic in cerebral ischemia/reperfusion (I/R) injury. The underlying association between autophagy and ferroptosis in ischemic stroke has not yet been clearly investigated. The purpose of this study was to explore the role of autophagy-related gene 5 (ATG5) in experimental ischemic stroke. After injection of ATG5 shRNA lentivirus, mice underwent surgery for transient middle cerebral artery occlusion (MCAO)-induced focal cerebral ischemia. The infarct volume, neurological function, apoptosis, reactive oxygen species (ROS), autophagy, and ferroptosis levels were evaluated. After MCAO, ATG5-knockdown mice had a smaller infarct size and fewer neurological deficits than wild-type mice. The levels of apoptosis and ROS in ischemic mouse brains were alleviated through ATG5 knockdown. The expression of LC3 I/II was reduced through ATG5 knockdown after MCAO. Additionally, the expression of beclin1 and LC3 II was increased after I/R, but the increase was counteracted by preconditioning with ATG5 knockdown. After ischemic stroke, the levels of Fe²⁺ and malondialdehyde (MDA) were increased, but they were reduced by ATG5 knockdown. Similarly, the expression of glutathione peroxidase 4 (GPX4) and glutathione (GSH) was decreased by I/R but elevated by ATG5 knockdown. The present study shows that ATG5 knockdown attenuates autophagy-induced ferroptosis, which may offer a novel potential approach for ischemic stroke treatment.