ATM inhibition attenuates ferroptosis-associated injury and reduces infarct volume in experimental stroke

Abstract

Aims: Ferroptosis, an iron-dependent form of regulated cell death, contributes to neuronal injury after ischemic stroke. Because our previous cancer-cell screens identified ataxia-telangiectasia mutated (ATM) kinase, as a ferroptosis regulator, we investigated whether ATM inhibition protects neural tissue after ischemic stroke and examined determinants of therapeutic response. Methods: ATM inhibitors, including the brain-penetrant clinical compound AZD1390, were evaluated in cultured cancer and neuronal cells, oxygen-glucose-deprived rat and mouse brain slices, and permanent middle cerebral artery occlusion models using multiple inbred and Rabep2-genotype mouse strains. Cell viability, cytotoxicity, lipid peroxidation, ferroptosis-associated markers, infarct volume, and collateral vessel density were assessed. Topical AZD1390 was also tested in mice with impaired collateral networks. Results: ATM inhibition reduced ferroptosis-associated lipid oxidative injury and protected neurons in multiple preclinical stroke models. AZD1390 decreased lipid peroxidation and neuronal death, and reduced infarct volume in B6/J and B6/NJ mice, but not in BALB mice. Treatment efficacy varied among strains and was correlated with collateral vascular density. Systemic AZD1390 was likewise ineffective in Rabep2-knockout mice with deficient collateral networks. Early topical administration also reduced infarct volume in mice with limited collateral networks; however, differences in treatment timing and route preclude direct attribution to improved local drug delivery. Conclusion: ATM inhibition may attenuate ferroptosis-associated neuronal injury after ischemic stroke, while collateral vascular anatomy may influence therapeutic response. These findings support further mechanistic and translational evaluation of ferroptosis-targeting strategies in stroke.