Contribution of MLKL to the development of doxorubicin-induced cardiomyopathy and its amelioration by rapamycin

• Published in: Journal of pharmacological sciences 2024-09, Vol.156 (1), p.9-18
• Main Authors: Shimizu, Masaki, Ohwada, Wataru, Yano, Toshiyuki, Kouzu, Hidemichi, Sato, Tatsuya, Ogawa, Toshifumi, Osanami, Arata, Toda, Yuki, Nagahama, Hiroshi, Tanno, Masaya, Miura, Tetsuji, Kuno, Atsushi, Furuhashi, Masato
• Format: Article
• Language: English
• Subjects: Animals; Antibiotics, Antineoplastic - adverse effects; Antibiotics, Antineoplastic - toxicity; Cardiomyopathies - chemically induced; Cardiomyopathies - metabolism; Cardiomyopathies - pathology; Cardiomyopathies - prevention & control; Cardiomyopathy; Doxorubicin; Doxorubicin - adverse effects; Male; Mice; Mice, Inbred C57BL; MLKL; Myocytes, Cardiac - drug effects; Myocytes, Cardiac - metabolism; Myocytes, Cardiac - pathology; Necroptosis; Necroptosis - drug effects; Protein Kinases - metabolism; Rapamycin; Receptor-Interacting Protein Serine-Threonine Kinases - genetics; Receptor-Interacting Protein Serine-Threonine Kinases - metabolism; Sirolimus - pharmacology
• ISSN: 1347-8613; 1347-8648; 1347-8648
• DOI: 10.1016/j.jphs.2024.06.005

Necroptosis, necrosis characterized by RIPK3-MLKL activation, has been proposed as a mechanism of doxorubicin (DOX)-induced cardiomyopathy. We showed that rapamycin, an mTORC1 inhibitor, attenuates cardiomyocyte necroptosis. Here we examined role of MLKL in DOX-induced myocardial damage and protective effects of rapamycin. Cardiomyopathy was induced in mice by intraperitoneal injections of DOX (10 mg/kg, every other day) and followed for 7 days. DOX-treated mice showed a significant decline in LVEF assessed by cardiac MRI (45.5 ± 5.1% vs. 65.4 ± 4.2%), reduction in overall survival rates, and increases in myocardial RIPK3 and MLKL expression compared with those in vehicle-treated mice, and those changes were prevented by administration of rapamycin (0.25 mg/kg) before DOX injection. In immunohistochemical analyses, p-MLKL signals were detected in the cardiomyocytes of DOX-treated mice, and the signals were reduced by rapamycin. Mlkl+/- and Mlkl-/- mice were similarly resistant to DOX-induced cardiac dysfunction, indicating that a modest reduction in MLKL level is sufficient to prevent the development of DOX-induced cardiomyopathy. However, evidence of cardiomyocyte necrosis assessed by C9 immunostaining, presence of replacement fibrosis, and electron microscopic analyses was negligible in the myocardium of DOX-treated mice. Thus, MLKL-mediated signaling contributes to DOX-induced cardiac dysfunction primarily by a necrosis-independent mechanism, which is inhibitable by rapamycin.