ALKBH5-mediated RNA N6-methyladenosine demethylation protects against myocardial I/R-induced injury via FSP1-dependent inhibition of ferroptosis

Nov 24, 2025Journal of molecular histology

RNA modification by ALKBH5 may protect the heart from injury after blood flow loss and return by stopping iron-related cell death through FSP1

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Abstract

ALKBH5 expression was significantly downregulated during myocardial ischemia/reperfusion injury, resulting in global RNA m6A hypermethylation.

Overexpression of ALKBH5 improved cardiac function and reduced infarct size in mouse models of ischemia/reperfusion injury.
ALKBH5 enhances cell viability and preserves mitochondrial membrane potential in cardiomyocytes under hypoxic conditions.
ALKBH5 directly binds to and demethylates m6A modifications on the mRNA of ferroptosis suppressor protein 1 (FSP1), increasing its stability and expression.
The upregulation of FSP1 is associated with the inhibition of ferroptosis, evidenced by decreased lipid peroxidation and reactive oxygen species accumulation.
The protective effects of ALKBH5 were mimicked by the ferroptosis inhibitor ferrostatin-1 and negated by FSP1 knockdown.

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Myocardial ischemia/reperfusion (I/R) injury represents a major clinical challenge, and ferroptosis has been identified as a crucial mechanism of cardiomyocyte death. While RNA N6-methyladenosine (m6A) modification is a dynamic regulator of gene expression, its role in myocardial I/R injury remains poorly defined. This study investigates the function of the m6A demethylase ALKBH5 and its underlying mechanism in counteracting ferroptosis during I/R injury. Using both ex vivo Langendorf I/R model, in vivo mouse I/R model and in vitro cardiomyocyte hypoxia/reoxygenation (H/R) models, we found that ALKBH5 expression was significantly downregulated, leading to global RNA m6A hypermethylation. ALKBH5 overexpression conferred robust cardioprotection, improving cardiac function, and reducing infarct size in mice, while enhancing cell viability and preserving mitochondrial membrane potential in cardiomyocytes. Mechanistically, RNA sequencing and mechanistic studies revealed that ALKBH5 directly binds to and demethylates m6A modifications on the mRNA of ferroptosis suppressor protein 1 (FSP1), thereby enhancing its mRNA stability and protein expression. The upregulation of FSP1 inhibited ferroptosis, as evidenced by reduced lipid peroxidation, iron overload, and reactive oxygen species accumulation, alongside increased levels of glutathione peroxidase 4 (GPX4). Crucially, the protective effects of ALKBH5 were mimicked by the ferroptosis inhibitor ferrostatin-1 and were completely abolished by FSP1 knockdown. Our findings unveil a novel ALKBH5/m6A/FSP1 signaling axis that critically suppresses ferroptosis, highlighting the therapeutic potential of targeting epitranscriptomic mechanisms for the treatment of ischemic heart disease.

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ALKBH5-mediated RNA N6-methyladenosine demethylation protects against myocardial I/R-induced injury via FSP1-dependent inhibition of ferroptosis

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