FIG. 7.

Role of Ref-1 in the redox control of cardiac stem cells. When adult cardiac stem cells are treated with 10 μM H₂O₂, Ref-1–mediated redox signaling is activated, leading to the protection of cells from injury. However, inhibition of Ref-1 through Ref-1 siRNA treatment resulted in the production of massive amounts of reactive oxygen species (ROS) and activation of NADPH oxidase, leading to p53-mediated apoptosis and differentiation in cardiac stem cells. Discontinuous line, Ref-1 may inhibit the massive production of ROS. Inhibition of Ref-1 with Ref-1 siRNA induces the production of massive amounts of ROS, leading to apoptosis and differentiation in adult cardiac stem cells.