METTL14 promotes hippocampal neuronal cuproptosis via m6A modification on FDX1 mRNA in cerebral ischemia-reperfusion injury

Cuproptosis, a consequence of excessively high copper concentrations, is considered a potential therapeutic target for cerebral ischemia-reperfusion injury (IRI). Methyltransferases are key modulators of cuproptosis through N6-methyladenosine (m6A) modification on ferredoxin 1 (FDX1) mRNA. This study aims to determine whether methyltransferase-like 14 (METTL14) regulates cuproptosis in cerebral IRI via m6A modification on FDX1 mRNA. The middle cerebral artery occlusion/reperfusion (MCAO/R)-treated mice, and oxygen glucose deprivation/reoxygenation-treated mouse primary hippocampal neurons were used to mimic cerebral IRI in vivo and in vitro, respectively. The functional role of METTL14 in cerebral IRI was determined by examining neurological functions, cerebral infarction, hippocampal CA1 tissue changes, neuronal viability, and cuproptosis using knockdown experiments. The involvement of FDX1 in the METTL14 regulatory pathway was verified by overexpressing FDX1. METTL14 expression was increased in the hippocampal tissue of mice subjected to MCAO/R. METTL14 knockdown reduced neurological deficits, infarct size, and hippocampal CA1 neuronal cuproptosis in MCAO/R mice. Furthermore, activation of hippocampal CA1 neuronal cuproptosis partly averted the alleviation of cerebral IRI by METTL14 knockdown. These results were reproduced in in vitro studies. Furthermore, mechanistic studies revealed that METTL14 knockdown reduced the stability of FDX1 mRNA through m6A modification and consequently limited FDX1 expression. Importantly, FDX1 overexpression could partly reverse the cuproptosis inhibition induced by METTL14 knockdown. Taken together, this research innovatively demonstrates the neuroprotective effect of METTL14 knockdown on hippocampal CA1 neurons in cerebral IRI via its regulation of FDX1, which might help design new therapies to improve cerebral IRI.