The ROS/NF-κB/NR4A2 pathway is involved in H₂O₂ induced apoptosis of resident cardiac stem cells via autophagy

Cardiac stem cells (CSCs)-based therapy provides a promising avenue for the management of ischemic heart diseases. However, engrafted CSCs are subjected to acute cell apoptosis in the ischemic microenvironment. Here, stem cell antigen 1 positive (Sca-1⁺) CSCs proved to own therapy potential were cultured and treated with H₂O₂ to mimic the ischemia situation. As autophagy inhibitor, 3-methyladenine (3MA), inhibited H₂O₂-induced CSCs apoptosis, thus we demonstrated that H₂O₂ induced autophagy-dependent apoptosis in CSCs, and continued to find key proteins responsible for the crosstalk between autophagy and apoptosis. Nuclear Receptor Subfamily 4 Group A Member 2 (NR4A2), increased upon cardiomyocyte injury with unknown functions in CSCs, was increased by H₂O₂. NR4A2 siRNA attenuated H₂O₂ induced autophagy and apoptosis in CSCs, which suggested an important role of NR4A2 in CSCs survival in ischemia conditions. Reactive oxygen species (ROS) and NF-κB (P65) subunit were both increased by H₂O₂. Either the ROS scavenger, N-acetyl-l-cysteine (NAC) or NF-κB signaling inhibitor, bay11-7082 could attenuate H₂O₂-induced autophagy and apoptosis in CSCs, which suggested they were involved in this process. Furthermore, NAC inhibited NF-κB activities, while bay11-7082 inhibited NR4A2 expression, which revealed a ROS/NF-κB/NR4A2 pathway responsible for H₂O₂-induced autophagy and apoptosis in CSCs. Our study supports a new clue enhancing the survival rate of CSCs in the infarcted myocardium for cell therapy in ischemic cardiomyopathy.