Supplementation of endothelial cells with mitochondria-targeted antioxidants inhibit peroxide-induced mitochondrial iron uptake, oxidative damage, and apoptosis.
The mitochondria-targeted drugs mitoquinone (Mito-Q) and mitovitamin E (MitoVit-E) are a new class of antioxidants containing the triphenylphosphonium cation moiety that facilitates drug accumulation in mitochondria. In this study, Mito-Q (ubiquinone attached to a triphenylphosphonium cation) and MitoVit-E (vitamin E attached to a triphenylphosphonium cation) were used. The aim of this study was to test the hypothesis that mitochondria-targeted antioxidants inhibit peroxide-induced oxidative stress and apoptosis in bovine aortic endothelial cells (BAEC) through enhanced scavenging of mitochondrial reactive oxygen species, thereby blocking reactive oxygen species-induced transferrin receptor (TfR)-mediated iron uptake into mitochondria. Glucose/glucose oxidase-induced oxidative stress in BAECs was monitored by oxidation of dichlorodihydrofluorescein that was catalyzed by both intracellular H(2)O(2) and transferrin iron transported into cells. Pretreatment of BAECs with Mito-Q (1 microM) and MitoVit-E (1 microM) but not untargeted antioxidants (e.g. vitamin E) significantly abrogated H(2)O(2)- and lipid peroxide-induced 2',7'-dichlorofluorescein fluorescence and protein oxidation. Mitochondria-targeted antioxidants inhibit cytochrome c release, caspase-3 activation, and DNA fragmentation. Mito-Q and MitoVit-E inhibited H(2)O(2)- and lipid peroxide-induced inactivation of complex I and aconitase, TfR overexpression, and mitochondrial uptake of (55)Fe, while restoring the mitochondrial membrane potential and proteasomal activity. We conclude that Mito-Q or MitoVit-E supplementation of endothelial cells mitigates peroxide-mediated oxidant stress and maintains proteasomal function, resulting in the overall inhibition of TfR-dependent iron uptake and apoptosis.[1]References
- Supplementation of endothelial cells with mitochondria-targeted antioxidants inhibit peroxide-induced mitochondrial iron uptake, oxidative damage, and apoptosis. Dhanasekaran, A., Kotamraju, S., Kalivendi, S.V., Matsunaga, T., Shang, T., Keszler, A., Joseph, J., Kalyanaraman, B. J. Biol. Chem. (2004) [Pubmed]
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