AATF alleviates cerebral ischemia-reperfusion injury by suppressing endoplasmic reticulum stress-induced ferroptosis through upregulating the PI3K/Akt pathway.

OBJECTIVE

The study aimed to investigate the role of apoptosis-antagonizing transcription factor (AATF) in regulating endoplasmic reticulum (ER) stress-ferroptosis interaction and its neuroprotective mechanism in cerebral ischemia-reperfusion injury (CIRI).

METHODS

Two models were used: oxygen-glucose deprivation/reperfusion (OGD/R)-induced hippocampal neuron cells and transient middle cerebral artery occlusion/reperfusion (tMCAO/R)-induced rats. AATF overexpression and knockdown were respectively performed to assess its impact on neuronal injury. Ferroptosis biomarkers - glutathione peroxidase 4 (GPX4), ferritin heavy chain 1 (FTH1), iron responsive element binding protein 2 (IREB2) and ER stress markers - phosphorylated eukaryotic initiation factor 2α (p-EIF2α)/EIF-2α, activating transcription factor 4 (ATF4) were analyzed by Western blot and enzyme-linked immunosorbent assay (ELISA). Pharmacological inhibitors or activators were utilized to explore the regulatory relationship between AATF, ER stress, and ferroptosis.

RESULTS

AATF was significantly upregulated during CIRI. AATF overexpression improved neuronal viability, reduced reactive oxygen species (ROS), and alleviated ferrous ion (Fe2+) accumulation; conversely, endogenous knockdown of AATF reversed its neuroprotective effects. Pathologically, AATF reduced cerebral infarction volume, neurological deficits, and brain edema. Mechanistic analysis showed that AATF inhibited the ER stress-ferroptosis axis by regulating related proteins. Pharmacological phosphatidylinositol 3-kinase (PI3K) inhibition reversed the neuroprotective effects of AATF, indicating the essential role of the PI3K- protein kinase B (Akt) signaling pathway in AATF-mediated suppression of both ferroptosis and ER stress.

DISCUSSION: AATF mitigates CIRI injury by modulating the ER stress-ferroptosis axis, primarily through the activation of the PI3K-Akt signaling pathway. These findings position AATF as a promising therapeutic target for brain ischemia-reperfusion injury.