Cerebral ischemic preconditioning promotes brain ischemic tolerance through N6-methyladenosine suppression of ACSL4-induced ferroptosis

Title : Cerebral ischemic preconditioning promotes brain ischemic tolerance through N6-methyladenosine suppression of ACSL4-induced ferroptosis

Abstract:

Cerebral ischemic preconditioning (CIP), a phenomenon in which a brief, sub-lethal ischemic episode confers robust protection against a subsequent severe stroke, is a powerful intrinsic mechanism for enhancing brain ischemic tolerance. Ferroptosis is now recognized as a critical pathogenic component in ischemic brain injury. Concurrently, the dynamic N⁶-methyladenosine (m⁶A) RNA modification has emerged as a crucial epitranscriptomic regulator of diverse cellular processes, including cell death pathways. The potential role of m⁶A signaling in modulating ferroptosis within the context of CIP-induced neuroprotection remains largely unexplored. This study aimed to investigate the hypothesis that m⁶A-dependent mechanisms mediate the anti-ferroptotic effects of CIP. Utilizing complementary in vivo (mouse transient middle cerebral artery occlusion, MCAO) and in vitro (oxygen-glucose deprivation, OGD in HT22 neuronal cells) models, we found that both CIP and pharmacological ferroptosis inhibition significantly attenuated ischemia-induced neuronal ferroptosis. We identified acyl-CoA synthetase long-chain family member 4 (ACSL4) as a central player. Similarly, in HT22 cells, mild OGD preconditioning (OGDP) attenuated the OGD-triggered upregulation of ACSL4. Crucially, overexpression of ACSL4 abolished the protective effect of OGDP against ferroptosis, confirming its essential role. Mechanistically, we discovered that OGD downregulated the m⁶A "eraser" protein FTO (fat mass and obesity-associated protein) while upregulating the m⁶A "reader" proteins IGF2BP1 and IGF2BP3. This shift in the m⁶A regulatory machinery enhanced the stability of ACSL4 mRNA, promoting its expression and subsequent ferroptosis. OGDP reversed this cascade by restoring FTO expression, reducing IGF2BP1/3 levels, and thereby accelerating m⁶A-dependent decay of ACSL4 mRNA. Collectively, our results demonstrate that CIP attenuates ACSL4-mediated ferroptosis via the m⁶A-FTO-IGF2BP1/3 axis to establish ischemic tolerance, revealing a novel and promising epitranscriptomic target for therapeutic intervention in ischemic stroke.

Biography:

Min Zhang, born in 1968, PhD, Professor and Doctoral Supervisor. She have been engaged in research on the induction and mechanisms of cerebral ischemic tolerance since 2005. She have presided over several projects from the National Natural Science Foundation of China and provincial natural science foundations. She have published more than 50 academic papers, including 18 SCI papers as the first author or corresponding author. Her papers have been cited 49 times at most, with 41 non-self-citations. She have received five Hebei Provincial Science and Technology Progress Awards, including one first prize in 2025, ranking first.