Aging-Associated ALKBH5-m⁶A Modification Exacerbates Doxorubicin-Induced Cardiomyocyte Apoptosis Via AT-Rich Interaction Domain 2

Background: Chemotherapy-induced cardiovascular disease is a growing concern in the elderly population who have survived cancer, yet the underlying mechanism remains poorly understood. We investigated the role of ALKBH5 (AlkB homolog 5), a primary N-6-methyladenosine (m(6)A) demethylase, and its involvement in m(6)A methylation-mediated regulation of targets in aging-associated doxorubicin-induced cardiotoxicity.Methods and results: To validate the relationship between doxorubicin-induced cardiotoxicity and aging, we established young and old male mouse models. ALKBH5 expression was modulated through adeno-associated virus 9 (in vivo), Lentivirus, and siRNAs (in vitro) to examine its impact on cardiomyocyte m(6)A modification, doxorubicin-induced cardiac dysfunction, and remodeling. We performed mRNA sequencing, methylated RNA immunoprecipitation sequencing, and molecular assays to unravel the mechanism of ALKBH5-m(6)A modification in doxorubicin-induced cardiotoxicity. Our data revealed an age-dependent increase in doxorubicin-induced cardiac dysfunction, remodeling, and injury. ALKBH5 expression was elevated in aging mouse hearts, leading to reduced global m(6)A modification levels. Through mRNA sequencing and methylated RNA immunoprecipitation sequencing analyses, we identified ARID2 (AT-rich interaction domain 2) as the downstream effector of ALKBH5-m(6)A modulation in cardiomyocytes. Further investigations revealed that ARID2 modulates DNA damage response and enhances doxorubicin-induced cardiomyocyte apoptosis.Conclusions: Our findings provide insights into the role of ALKBH5-m(6)A modification in modulating doxorubicin-induced cardiac dysfunction, remodeling, and cardiomyocyte apoptosis in male mice. These results highlight the potential of ALKBH5-targeted treatments for elderly patients with cancer in clinical settings.