N6-methyladenosine demethylase ALKBH5 mediates remote ischemic postconditioning in cerebral ischemia-reperfusion injury by regulating KLF4

This study aimed to investigate the role of the m6A demethylase ALKBH5 in RIPostC against CI/R injury and its underlying regulatory mechanism. A rat model of CI/R was established using the MCAO method. Subsequently, RIPostC was performed to evaluate its therapeutic potential against CI/R injury. The effects of overexpressing ALKBH5 and KLF4 on CI/R injury were also examined in the rat model. A cellular model of CI/R was established by inducing OGD/R in PC12 cells. The effects of ALKBH5 and KLF4 on cellular function in the CI/R model were investigated, and the specific regulatory role of ALKBH5 in the m 6 A modification of KLF4 was elucidated. The mRNA expression of ALKBH5 and KLF4 in acute ischemic stroke patients and healthy individuals was measured by RT-qPCR. The results demonstrated that ALKBH5 and KLF4 expression was decreased in acute ischemic stroke patients, as well as in CI/R rats and OGD/R-induced cells. RIPostC treatment alleviated MCAO-induced neurological deficits, reduced cerebral infarct volume, apoptosis, and inflammatory cytokines levels. Furthermore, RIPostC upregulated the expression of ALKBH5 and KLF4 in CI/R rats. Overexpression of ALKBH5 and KLF4 further enhanced the therapeutic efficacy of RIPostC in CI/R rats. Overexpression of ALKBH5 and KLF4 alleviated OGD/R-induced cellular injury. Mechanistically, overexpression of ALKBH5 upregulated KLF4 expression by promoting m6A demethylation of KLF4 mRNA. In conclusion, overexpression of ALKBH5 upregulates KLF4 by promoting m 6 A demethylation modification, thereby attenuating CI/R injury.