Inhibition of mitochondrial superoxide promotes the development of hiPS-CMs during differentiation

The redox state is a crucial determinant of the maturation transition of cardiomyocytes in vivo. Mitochondria, the primary site of superoxide generation, are very sensitive to various stimulations, including oxygen and nutrient supply. How mitochondrial superoxide affects the differentiation and development of induced pluripotent stem cell (iPSC)-derived cardiac myocytes (iPS-CMs) is not completely clear. To address the questions, we monitored the superoxide level during the differentiation and development of human iPS-CMs using MitoSOX. Mitochondria-targeted antioxidant Mito-TEMPO was used to treat hiPS-CMs in the differentiation period. We found that mitochondrial superoxide generation was dramatically enhanced during the differentiation and early development of iPS-CMs. Increased oxidative stress induced oxidative damage to macromolecules in iPS-CMs, such as lipids, proteins, and DNA. Mito-TEMPO protected mitochondrial functions, alleviated oxidative damage to lipids, proteins, and DNA and improved cellular structure and fatty acid utilization. Our findings confirmed that iPS-CM suffered from oxidative stress during differentiation and that mitochondrial-targeted antioxidant is beneficial for the maturation of iPS-CMs.