METTL3-Mediated m6A Modification of ISG15 mRNA Regulates Doxorubicin-Induced Endothelial Cell Apoptosis

N6-adenosine methylation (m6A) of RNA is involved in the regulation of various diseases. However, its role in chemotherapy-related vascular endothelial injury has not yet been elucidated. We found that methyltransferase-like 3 (METTL3) expression was significantly reduced during doxorubicin (DOX)-induced apoptosis of vascular endothelial cells both in vivo and in vitro, and that silencing of METTL3 further intensified this process. Combined transcriptome and proteome sequencing analyses revealed that the expression levels of interferon-stimulated gene 15 (ISG15) mRNA and protein significantly increased after METTL3 silencing. Methylated RNA immunoprecipitation (meRIP)-quantitative polymerase chain reaction (qPCR) and mRNA stability assays confirmed that METTL3 regulates the expression of ISG15 by methylating the 1,014,147 site on ISG15 RNA, thereby decreasing ISG15 mRNA levels. Silencing ISG15 significantly suppressed DOX-induced endothelial cell apoptosis and dysfunction caused by METTL3 silencing. In summary, our study revealed that METTL3-mediated methylation of ISG15 mRNA is involved in DOX-induced endothelial cell apoptosis and explored potential therapeutic targets for alleviating chemotherapy-associated vascular injury.