Cardioprotective effects of fibroblast growth factor 21 against doxorubicin-induced toxicity via the SIRT1/LKB1/AMPK pathway

Doxorubicin (DOX) is a highly effective antineoplastic anthracycline drug; however, the adverse effect of the cardiotoxicity has limited its widespread application. Fibroblast growth factor 21 (FGF21), as a well-known regulator of glucose and lipid metabolism, was recently shown to exert cardioprotective effects. The aim of this study was to investigate the possible protective effects of FGF21 against DOX-induced cardiomyopathy. We preliminarily established DOX-induced cardiotoxicity models in H9c2 cells, adult mouse cardiomyocytes, and 129S1/SyImJ mice, which clearly showed cardiac dysfunction and myocardial collagen accumulation accompanying by inflammatory, oxidative stress, and apoptotic damage. Treatment with FGF21 obviously attenuated the DOX-induced cardiac dysfunction and pathological changes. Its effective anti-inflammatory activity was revealed by downregulation of inflammatory factors (tumor necrosis factor-a and interleukin-6) via the IKK/I kappa B alpha/nuclear factor-kappa B pathway. The anti-oxidative stress activity of FGF21 was achieved via reduced generation of reactive oxygen species through regulation of nuclear transcription factor erythroid 2-related factor 2 transcription. Its anti-apoptotic activity was shown by reductions in the number of TUNEL-positive cells and DNA fragments along with a decreased ratio of Bax/Bcl-2 expression. In a further mechanistic study, FGF21 enhanced sirtuin 1 (SIRT1) binding to liver kinase B1 (LKB1) and then decreased LKB1 acetylation, subsequently inducing AMP-activated protein kinase (AMPK) activation, which improved the cardiac inflammation, oxidative stress, and apoptosis. These alterations were significantly prohibited by SIRT1 RNAi. The present work demonstrates for the first time that FGF21 obviously prevented DOX-induced cardiotoxicity via the suppression of oxidative stress, inflammation, and apoptosis through the SIRT1/LKB1/AMPK signaling pathway.