Abstract
In a screening program to discover therapeutic drugs for heart diseases, we identified BTZO-1, a 1,3-benzothiazin-4-one derivative, which activated antioxidant response element (ARE)-mediated gene expression and suppressed oxidative stress-induced cardiomyocyte apoptosis in vitro. An active BTZO-1 derivative for ARE-activation protected heart tissue during ischemia/reperfusion injury in rats. Macrophage migration inhibitory factor (MIF), which is known to protect cells from oxidative insult, was identified as a specific BTZO-1-binding protein. BTZO-1 binds to MIF with a K(d) of 68.6 nM, and its binding required the intact N-terminal Pro1. MIF, in the presence of BTZO-1, activated the glutathione S-transferase Ya subunit (GST Ya) gene ARE, whereas reduction of cellular MIF protein levels by siRNA suppressed BTZO-1-induced GST Ya expression. These results suggest that BTZO-1 activates the GST Ya gene ARE by interacting with MIF.