m6A Demethylase ALKBH5 attenuates doxorubicin-induced cardiotoxicity via posttranscriptional stabilization of Rasal3

The clinical application of anthracyclines such as doxorubicin (DOX) is limited due to their cardiotoxicity. N6-methyladenosine (m6A) plays an essential role in numerous biological processes. However, the roles of m6A and m6A demethylase ALKBH5 in DOX-induced cardiotoxicity (DIC) remain unclear. In this research, DIC models were constructed using Alkbh5-knockout (KO), Alkbh5-knockin (KI), and Alkbh5-myocardial-specific knockout (ALKBH5flox/flox, aMyHC-Cre) mice. Cardiac function and DOX-mediated signal transduction were investigated. As a result, both Alkbh5 whole-body KO and myocardial-specific KO mice had increased mortality, decreased cardiac function, and aggravated DIC injury with severe myocardial mitochondrial damage. Conversely, ALKBH5 overexpression alleviated DOX-mediated mitochondrial injury, increased survival, and improved myocardial function. Mechanistically, ALKBH5 regulated the expression of Rasal3 in an m6A-dependent manner through posttranscriptional mRNA regulation and reduced Rasal3 mRNA stability, thus activating RAS3, inhibiting apoptosis through the RAS/RAF/ERK signaling pathway, and alleviating DIC injury. These findings indicate the potential therapeutic effect of ALKBH5 on DIC. Overall design: We performed MeRIP-seq and MeRIP-seq-Qpcr analysis on the myocardial tissues of ALKBH5flox/flox (n = 3, ALKBH5flox/flox-DOX group) and ALKBH5flox/flox, aMyHC-Cre (n = 3, ALKBH5flox/flox, aMyHC-Cre-DOX group) treated with doxorubicin.