Cardioprotective Effect of Growth Differentiation Factor 15 Against Isoproterenol-Induced Cardiomyocyte Apoptosis via Regulation of the Mitochondrial Fusion

Objective: Pressure overload-induced myocardial apoptosis is a critical pathologically initiated process leading to heart failure (HF). Growth differentiation factor 15 (GDF15) dramatically increases during cardiac hypertrophy and dysfunction, but its functions and mechanisms are barely known. This study aims to elucidate the role and mechanism of GDF15 in HF. Methods: Between January 2017 and August 2018, 57 patients diagnosed with chronic HF (aged >18 years, with left ventricular ejection fraction (LVEF) <= 35%) and 57 non-HF patients (aged >18 years, LVEF >35%) were prospectively enrolled in this study based on the balance of the baseline characteristics. Other acute or chronic diseases and pregnant/lactating women were excluded. The serum concentrations of GDF15 were detected. Isoproterenol (ISO)-induced HF mouse model was established by pumping with ISO (30 mg/(kg<middle dot>day)) for 4 weeks, and the GDF15 expression in serum and heart tissue was evaluated in vivo. Primary cardiomyocytes were cultured and treated with ISO to induce cardiomyocytes damage. The apoptosis of cardiomyocytes and the effect of GDF15 on ISO-induced cardiomyocytes injury was evaluated in vitro. Results: After adjusting the baseline characteristic, serum levels of GDF15 were significantly higher in HF subjects than in non-HF patients. Similarly, in the ISO-induced HF mouse model, the significant increase in GDF15 was associated with the process of HF in vivo. Moreover, the elevation of GDF15 occurred prior to heart remodeling in the ISO-induced HF mouse model. Furthermore, using primary cardiomyocytes, we demonstrated that the GDF15 was remarkably enhanced in serum from pathological HF patients and cardiac tissue from the ISO-induced mouse model. Reducing GDF15 exaggerated the ISO-induced cell apoptosis by blocking mitochondrial fusion and increasing oxidative stress. In contrast, the silence of GDF15 aggravated the ISO-induced cardiomyocytes damage. Conclusions: GDF15 acts as a protective factor against cardiomyocyte apoptosis by improving mitochondria fusion during HF. These findings indicate that GDF15 may be a potential therapeutic target for HF.