Mdivi 1

Mdivi-1 is a selective cell-permeable inhibitor of mitochondrial division DRP1 (dynamin-related GTPase) and mitochondrial division Dynamin I (Dnm1) with IC50 of 1-10 μM. (In Vitro) :Mdivi-1 inhibits Dnm1 GTPase activity in a dose-dependent manner, with an estimated EC50 of 1-10 μM. Mdivi-1 increases the apparent K0.5 for GTP, lowers the apparent Vmax for GTP hydrolysis, and causes an increase in the Hill coefficient observed for GTP in the Dnm1 GTP hydrolysis reaction. Cells treated with mdivi-1 display decreased cytochrome c release and a reduced rate of phosphatidylserine exposure on their surface following apoptosis induction, consistent with an inhibition of apoptosis and with previous studies using other strategies to compromise DRP1 activity. Mdivi-1 results in apoptotic cell death in ischemic retina. (In Vivo) :The mitochondrial division DRP, Dnm1, is the target of mdivi-1 in vivo. Mdivi-1 quantitatively blocks GMPPCP- dependent Dnm1 self-assembly in a concentration range similar to its effects on mitochondrial division in vivo. Mdivi-1 (50 mg/kg, i.p.) significantly decreases GFAP protein expression in the normal mouse retina.