title: Low Concentrations of Uncouplers of Oxidative Phosphorylation Prevent Inflammatory Activation of Endothelial Cells by Tumor Necrosis Factor.
abstract: In endothelial cells, mitochondria play an important regulatory role in physiology as well as in pathophysiology related to excessive inflammation. We have studied the effect of low doses of mitochondrial uncouplers on inflammatory activation of endothelial cells using the classic uncouplers 2,4-dinitrophenol and 4,5,6,7-tetrachloro-2-trifluoromethylbenzimidazole, as well as the mitochondria-targeted cationic uncoupler dodecyltriphenylphosphonium (C12TPP). All of these uncouplers suppressed the expression of E-selectin, adhesion molecules ICAM1 and VCAM1, as well as the adhesion of neutrophils to endothelium induced by tumor necrosis factor (TNF). The antiinflammatory action of the uncouplers was at least partially mediated by the inhibition of NFκB activation due to a decrease in phosphorylation of the inhibitory subunit IκBα. The dynamic concentration range for the inhibition of ICAM1 expression by C12TPP was three orders of magnitude higher compared to the classic uncouplers. Probably, the decrease in membrane potential inhibited the accumulation of penetrating cations into mitochondria, thus lowering the uncoupling activity and preventing further loss of mitochondrial potential. Membrane potential recovery after the removal of the uncouplers did not abolish its antiinflammatory action. Thus, mild uncoupling could induce TNF resistance in endothelial cells. We found no significant stimulation of mitochondrial biogenesis or autophagy by the uncouplers. However, we observed a decrease in the relative amount of fragmented mitochondria. The latter may significantly change the signaling properties of mitochondria. Earlier we showed that both classic and mitochondria-targeted antioxidants inhibited the TNF-induced NFκB-dependent activation of endothelium. The present data suggest that the antiinflammatory effect of mild uncoupling is related to its antioxidant action.
authors.affiliation: Lomonosov Moscow State University, Belozersky Institute of Physico-Chemical Biology, Moscow, 119991, Russia. k_popova_ch@mail.ru.
authors.forename: V P
authors.initials: VP
authors.lastname: Romaschenko
authors.forename: R A
authors.initials: RA
authors.lastname: Zinovkin
authors.forename: I I
authors.initials: II
authors.lastname: Galkin
authors.forename: V V
authors.initials: VV
authors.lastname: Zakharova
authors.forename: A A
authors.initials: AA
authors.lastname: Panteleeva
authors.forename: A V
authors.initials: AV
authors.lastname: Tokarchuk
authors.forename: K G
authors.initials: KG
authors.lastname: Lyamzaev
authors.forename: O Yu
authors.initials: OY
authors.lastname: Pletjushkina
authors.forename: B V
authors.initials: BV
authors.lastname: Chernyak
authors.forename: E N
authors.initials: EN
authors.lastname: Popova
mesh_terms: D000975:Antioxidants / Q000494:pharmacology*; D002448:Cell Adhesion / Q000187:drug effects; D002460:Cell Line; D004305:Dose-Response Relationship, Drug; D019040:E-Selectin / Q000378:metabolism; D042783:Endothelial Cells / Q000378:metabolism* / Q000473:pathology; D005786:Gene Expression Regulation / Q000187:drug effects*; D006801:Humans; D020672:I-kappa B Proteins / Q000378:metabolism; D007249:Inflammation / Q000378:metabolism / Q000473:pathology; D018799:Intercellular Adhesion Molecule-1 / Q000378:metabolism; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects; D016328:NF-kappa B / Q000378:metabolism; D009504:Neutrophils / Q000378:metabolism* / Q000473:pathology; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis*; D014475:Uncoupling Agents / Q000494:pharmacology*; D019010:Vascular Cell Adhesion Molecule-1 / Q000378:metabolism
chemical_list: D000975:Antioxidants; D019040:E-Selectin; D020672:I-kappa B Proteins; C573420:ICAM1 protein, human; D016328:NF-kappa B; C439524:TNF protein, human; D014409:Tumor Necrosis Factor-alpha; D014475:Uncoupling Agents; D019010:Vascular Cell Adhesion Molecule-1; D018799:Intercellular Adhesion Molecule-1