ИСТИНА

Using mitochondria-targeted antioxidants made of plastoquinone and penetrating cations (SkQ family), we investigated the role of mitochondrial reactive oxygen species (ROS) in the TNF-induced cytoskeleton reorganization and apoptosis in endothelial cells. SkQ, as well as the classic antioxidant N-acetylcysteine and Trolox significantly suppressed apoptosis induced by TNF [1]. Their action was directed at the suppressing the release of cytochrome c. We showed that SkQ treatment led to an increased level of Bcl-2, and reduced levels of Bax and p53 [1]. Nevertheless, SkQ had no on Bcl-2 mRNA expression, but it enhances Bcl-2 phosphorylation thus contributing to the inhibition of protein ubiquitination. We have also shown that SkQ prevents Bcl- 2 proteolysis induced by TNF. We assume that SkQ may affect activation of the redox sensitive stress kinases that are involved in the phosphorylation of the Bcl-2 family proteins. In our system we plan to evaluate the influence of mitochondria-targeted antioxidants on DNA damage induced by TNF. The results will be presented at the conference. We showed that SkQ as well as N-acetylcysteine and Trolox inhibited TNF-induced monolayer endothelial permeability for dextran with a molecular weight of 65-85 kDa. Endothelial monolayer permeability induced by TNF is accompanied by cytoskeleton reorganization. We observed that SkQ prevented TNF -induced release of VE- cadherin and β- catenin from the contact area, as well as disassembly of the annular peripheral beam of actin microfilaments. TNF-activated matrix metalloproteinases (MMP) cleaved extracellular fragment of VE- cadherins. We observed MMP-dependent decrease in the overall VE- cadherin level in the cells and the appearance of its cleavage product in cell medium induced by TNF. These effects were markedly suppressed by SkQ. Thus, it was shown that TNF-dependent endothelial cell damage was largely dependent.