The demethylase FTO regulates the m6A modification and inflammation pathway in patients with cardiomyocytes after hypoxia-reoxygenation

Background Myocardial ischemia-reperfusion injury is an important clinical problem. Hypoxia-reperfusion(HR) triggers a series of complex cellular reactions and pathological changes. In recent years, the role of N-6-methyladenosine(m6A) modification in gene expression regulation has received extensive attention. New evidence suggests that m6A modifications may play a key role in the regulation of cellular responses to HR-damaged cardiomyocytes. Inflammation is an important part of the pathogenesis of myocardial ischemia-reperfusion injury. In the HR response, inflammatory factors such as interleukin(IL), tumor necrosis factor(TNF-α) and other cytokines are released and activated, which can trigger a series of intracellular signaling pathways leading to myocardial cell damage, apoptosis, and inflammation. In the context of cardiomyocyte H/R injury, it is important to study the relationship between m6A modification and the regulation of inflammatory cytokines expression. It is of great significance to fully understand the underlying mechanism of myocardial ischemia-reperfusion injury and develop new therapeutic strategies. Methods The hypoxic-reoxygenation model of H9C2 cells was established, and the overexpression and knockout model of fat mass and obesity associated gene(FTO) was established. The cells were divided into 6 groups: control group(CG), hypoxic-reperfusion group(HRG), FTO overexpression group(OG), FTO overexpression hypoxic-reperfusion group(OHG), FTO knockout group(KG) and FTO knockout hypoxic-reperfusion group(KHG). The changes of M6A were detected by colorimetry, FTO expression was detected by Western Blot, and the changes of FTO and phosphorylated nuclear factor kappa B(P-NF-κB) were observed by immunofluorescence. IL-6 was detected by enzymelinked immunosorbent assay(ELISA). Results The level of m6A in HRG was significantly higher than that in CG(P<0.05). The same pattern was observed in OG and KG(P<0.05). The level of m6A in KHG were higher than that in HRG, while lower in OHG than that in HRG(P<0.05). The expression of FTO decreased during hypoxia and reoxygenation(P<0.05). The expression of FTO in KHG was lower than that in KG(P<0.05). There was no significant difference in FTO expression between OG and OHG(P>0.05). Compared with HRG, FTO in OHG was decreased(P<0.01). Compared with HRG, FTO in KHG was decreased(P<0.01). The changes of P-NF-κB and IL-6 were consistent before and after hypoxia reoxygenation. The expression of these two inflammatory factors in HRG was significantly higher than that in CG(P<0.05). OHG compared with HRG, the two groups of inflammatory factors decreased; KHG was significantly higher than HRG(P<0.05). Conclusions Overexpression of FTO can significantly inhibit the increase of m6A, reduce inflammatory factors, and protect damaged cells during hypoxia and re-oxidation processes. [S Chin J Cardiol 2024; 25(3):169-178]