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.

Aged kidney: can we protect it? Autophagy, mitochondria and mechanisms of ischemic preconditioning

“…In the nearest future, we can expect the emergence of new uncouplers with an increasingly wide therapeutic window. The uncouplers were shown to prevent proinflammatory changes in endothelial cells in vitro and animal death induced inflammation, indicating an important role for mitochondria in the regulation of inflammatory response [110,111]. Translation these results from the bench to the bed implies the possibility of treatment with uncouplers of a late diagnosed AKI through inhibition of inflammatory processes in the organism.…”

Mitochondria‐Targeted Antioxidants and Uncouplers of Oxidative Phosphorylation in Treatment of the Systemic Inflammatory Response Syndrome (SIRS)

“…As a result, C 12 TPP catalyzed transmembrane translocation of the deprotonated FFA which is the limiting step in protonophorous FFA cycling. C 12 TPP inhibited TNF-stimulated expression of ICAM1, VCAM1, and neutrophil adhesion to the surface of endothelial cells (Romaschenko et al, 2015). Dodecyl(triphenyl)phosphonium rhodamine-19 (C 12 R1) and propyl(triphenyl)phosphonium rhodamine-19 (C 4 R1) were shown to be cationic protonophores due to protonation-deprotonation cycling of the rhodamine residue (Khailova et al, 2014).…”

“…As a result, C 12 TPP catalyzed transmembrane translocation of the deprotonated FFA which is the limiting step in protonophorous FFA cycling. C 12 TPP inhibited TNF‐stimulated expression of ICAM1 , VCAM1 , and neutrophil adhesion to the surface of endothelial cells (Romaschenko et al, ).…”

Insights into the molecular mechanisms of diabetes-induced endothelial dysfunction: focus on oxidative stress and endothelial progenitor cells

“…The use of anti-oxidants and their subsequent downstream effects attenuates the activation/ phosphorylation of p38 mitogen activated protein kinase (MAPK) and c-Jun N-terminal kinase (JNK) pathways by TGF-b, thus inhibiting ECs apoptosis [28]. Uncouplers of oxidative phosphorylation decrease ROS production in mitochondria which inhibit inhibitor of kappa B (IjB) phosphorylation, inciting a state of resistance to tumor necrosis factor-a (TNF-a) activation of Nuclear factor jB (NF-jB) signaling pathway and inflammation in ECs [29]. Moreover, H 2 O 2 and peroxynitrite-mediated activation of poly (ADPribose) polymerase (PARP-1) depletes cellular ATP and NAD ?…”