Adropin Alleviates High-Glucose-Induced Cardiomyocyte Apoptosis In Vitro via the Modulation of Mitophagy and Mitochondrial Dynamics

Background and Objective: Diabetic cardiomyopathy (DbCM) is a serious complication of diabetes. Adropin (ADR), a 76-amino acid peptide encoded by the Energy homeostasis associated (Enho) gene, plays a crucial role in energy homeostasis. However, the effects of (Enho) on cardiomyocytes (CMs) apoptosis under hyperglycemic conditions and the associated mechanisms remain poorly understood. Thus, this study aimed to investigate the protective effects of ADR against high glucose-induced CM apoptosis and elucidate the underlying mechanisms involving mitophagy and mitochondrial dynamics. Materials and Methods: Neonatal rat CMs were cultured in vitro and divided into three groups: control (CMs), high glucose condition (HGLc; CMs + HGLc), and HGLc with ADR treatment (CMs + HGLc + ADR). Cell viability was assessed using the MTT assay, while apoptosis was quantified by flow cytometry. Lysosomal activity was evaluated via fluorescent probes, and autophagic flux was measured using the monomeric Red Fluorescent Protein-enhanced Green Fluorescent Protein-Microtubule-associated protein 1 light chain 3 (mRFP-eGFP-LC3) dual-fluorescence system. The expression of Proteins invoved in mitophagy and mitochondrial dynamics was analyzed by Western blotting. Results: High glucose exposure significantly reduced CM viability, increased apoptosis, and impaired mitochondrial membrane potential and autophagy (p < 0.05 vs. the controls group). These effects were accompanied by downregulation of sequestosome 1 (p62), PTEN-induced kinase 1 (PINK1), Parkin, Mitofusin 1 (Mfn1), and Mitofusin 2 (Mfn2), and upregulation of Dynamin-related protein 1 (Drp1) . ADR treatment attenuated these abnormalities, restoring viability, reducing apoptosis, and improving mitochondrial function and autophagy (p < 0.05 vs. CMs + HGLc group). Notably, ADR upregulated p62, PINK1, Parkin, Mfn1 and Mfn2 while suppressing Drp1 expression (p < 0.05 vs CMs + HGLc group). Conclusion: ADR mitigates high glucose-induced CMs apoptosis by enhancing mitophagy and restoring mitochondrial dynamics, suggesting that ADR treatment offers therapeutic potential for DbCM.