Inhibition of aldehyde dehydrogenase 2 activity enhances antimycin-induced rat cardiomyocytes apoptosis through activation of MAPK signaling pathway

Aldehyde dehydrogenase 2 (ALDH2), a mitochondrial-specific enzyme, has been proved to be involved in oxidative stress-induced cell apoptosis, while little is known in cardiomyocytes. This study was aimed at investigating the role of ALDH2 in antimycin A-induced cardiomyocytes apoptosis by suppressing ALDH2 activity with a specific ALDH2 inhibitor Daidzin. Antimycin A (40 μg/ml) was used to induce neonatal cardiomyocytes apoptosis. Daidzin (60 μM) effectively inhibited ALDH2 activity by 50% without own effect on cell apoptosis, and significantly enhanced antimycin A-induced cardiomyocytes apoptosis from 33.5 ± 4.4 to 56.5 ± 6.4% (Hochest method, p < 0.05), and from 57.9 ± 1.9 to 74.0 ± 11.9% (FACS, p < 0.05). Phosphorylation of activated MAPK signaling pathway, including extracellular signal-regulated kinase (ERK1/2), c-Jun NH2-terminal kinase (JNK) and p38 was also increased in antimycin A and daidzin treated cardiomyocytes compared to the cells treated with antimycin A alone. These findings indicated that modifying mitochondrial ALDH2 activity/expression might be a potential therapeutic option on reducing oxidative insults induced cardiomyocytes apoptosis.