[Deposition of von Willebrand factor in human endothelial cells HUVEC in the endoplasmic reticulum stress induced by an excess of homocysteine in vitro].

Von Willebrand factor (vWF) is an adhesive glycoprotein synthesized and secreted by endothelial cells and megakaryocytes. Violation of vWF secretion by endothelial cells is a characteristic feature of endothelial dysfunction in hyperhomocysteinemia. In our study we examined to clarify the concentration-dependent effect of homocysteine (Hcy) on the expression of vWF. Our studies have shown that homocysteine excess induces changes in the intracellular deposition of von Willebrand factor in cultured human endothelial cells in vitro. Primary cultures of human umbilical vein endothelial cells (HUVEC) were incubated with the various concentrations of D,L-homocysteine (0.025 - 5 mM). Homocysteine at a concentration of 0.025 and 0.25 mM after 18 h incubation caused an increase in the intracellular fraction of vWF in HUVEC cells. High concentrations of homocysteine induced a dose-dependent decrease in the intracellular fraction of vWF. These dose-dependent variations may indicate the modulation by homocysteine of different mechanisms of the deposition, the constitutive secretion and the degradation of vWF in human endothelial cells. We proposed that Endoplasmic reticulum stress, in HUVEC cells by the action of an excess of homocysteine associated with increased intracellular levels of vWF at a relatively low concentration of the inducer. We found decline in intracellular vWF at the same duration but higher concentrations of inducer, which may be due to the ER-associated protein degradation.

[Induction of the endoplasmic reticulum stress in conditions of acid-base imbalance in human cells of T-lymphoblastic leukemia].

Endoplasmic reticulum stress - typical molecular pathophysiological process that underlies many cardiovascular, endocrine and other diseases. Violations of the protein conformational maturation processes in the endoplasmic reticulum can cause proteotoxic stress. Compensatory mechanisms are activated in response to ER stress include increased expression of enzymes involved in the formation of disulfide bonds in proteins. The sulfhydryl groups oxidation in the electron transport chain (PDI-ERO1-O2) is associated with reactive oxygen species (ROS) generation. Increased activity of oxidoreductase ERO1 could be one of the mechanisms of oxidative stress - however, a direct relationship of ER stress with the overproduction of ROS remains a subject of debate. In this study we have shown that induced by dithiothreitol (DTT) violation of the redox balance with low ROS production leads to the endoplasmic reticulum stress in Jurkat cells. ER-stress in these cells is not associated with increased ROS production, DTT treatment leads to induction of apoptosis. Modulation of intracellular levels of ROS can influence the apoptosis-inducing effects of ER-stress. Given the possible involvement of ROS in the generation of disulfide bonds, the role of ROS in ER stress may be a modulation of disulfide proteome including client proteins.