title: Supplementation of endothelial cells with mitochondria-targeted antioxidants inhibit peroxide-induced mitochondrial iron uptake, oxidative damage, and apoptosis.
abstract: 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.
authors.affiliation: Department of Biophysics and Free Radical Research Center, Medical College of Wisconsin, Milwaukee, Wisconsin 53226, USA.
authors.forename: Anuradha
authors.initials: A
authors.lastname: Dhanasekaran
authors.forename: Srigiridhar
authors.initials: S
authors.lastname: Kotamraju
authors.forename: Shasi V
authors.initials: SV
authors.lastname: Kalivendi
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Matsunaga
authors.forename: Tiesong
authors.initials: T
authors.lastname: Shang
authors.forename: Agnes
authors.initials: A
authors.lastname: Keszler
authors.forename: Joy
authors.initials: J
authors.lastname: Joseph
authors.forename: B
authors.initials: B
authors.lastname: Kalyanaraman
mesh_terms: D000154:Aconitate Hydratase / Q000037:antagonists & inhibitors; D000818:Animals; D000975:Antioxidants / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D002417:Cattle; D002478:Cells, Cultured; D042967:Electron Transport Complex I / Q000037:antagonists & inhibitors; D004730:Endothelium, Vascular / Q000187:drug effects* / Q000378:metabolism; D005949:Glucose Oxidase / Q000494:pharmacology; D020287:In Situ Nick-End Labeling; D007501:Iron / Q000378:metabolism*; D008928:Mitochondria / Q000187:drug effects* / Q000378:metabolism; D018384:Oxidative Stress / Q000187:drug effects*; D010545:Peroxides / Q000037:antagonists & inhibitors*; D011990:Receptors, Transferrin / Q000502:physiology
chemical_list: D000975:Antioxidants; D010545:Peroxides; D011990:Receptors, Transferrin; D007501:Iron; D005949:Glucose Oxidase; D000154:Aconitate Hydratase; D042967:Electron Transport Complex I