KLHL8-mediated ubiquitination and TAX1BP1-dependent autophagic degradation of GPX4 drive neuronal ferroptosis.

Ferroptosis, characterized by iron-dependent lipid peroxidation, is considered a key cell death pathway activated during ischemic stroke. GPX4, a negative regulator of ferroptosis, exacerbates brain damage. However, the precise regulatory mechanisms governing this process remain poorly understood. Here, we determined that oxygen-glucose deprivation/reoxygenation (OGD/R)-induced GPX4 degradation is primarily dependent on autophagy activation. Mechanistically, the E3 ubiquitin ligase KLHL8 tags GPX4 through ubiquitination and promotes its binding to the selective autophagy receptor TAX1BP1, thereby synergistically mediating GPX4's autophagic-lysosomal degradation. Clinical database analysis also confirmed that KLHL8 and TAX1BP1 expression are significantly upregulated in brain tissue from patients with ischemic stroke and positively correlated with ferroptosis scores. Therapeutic approaches have shown that AAV-mediated GPX4 overexpression or the use of autophagy inhibitors can effectively stabilize GPX4 levels, inhibit neuronal ferroptosis, and significantly improve cerebral infarction and neurological function in mice undergoing middle cerebral artery occlusion (MCAO). In particular, the combination of GPX4 overexpression and artesunate demonstrated a potent synergistic neuroprotective effect. These findings suggest that a cascade consisting of KLHL8-mediated ubiquitination and TAX1BP1-mediated selective autophagy is a key pathway for GPX4 degradation, and that the KLHL8-TAX1BP1-GPX4 regulatory axis provides a potential therapeutic target for ischemic stroke.