[The Thymic Hormone Thymosin-1α Reduces the Pro-Inflammatory Response of Raw 264.7 Cells Induced by Endotoxin].

The aim of this work was to study the effects of thymosin-1 alpha (Tα1) on the anti-inflammatory response of RAW 264.7 macrophages cultured in the presence of lipopolysaccharide (LPS) from the walls of gram-negative bacteria. As well, we evaluated production of pro-inflammatory cytokines and the activity of the NF-κB and SAPK/JNK signaling pathways. In addition, the level of expression of a number of genes that regulate cell apoptosis, as well as the activity of receptors involved in the pro-inflammatory response, was determined. First, the addition of Tα1 normalized the level of cytokine production to varying degrees, with a particularly noticeable effect on IL-1ß and IL-6. Second, the addition of Tα1 normalized the activity of the NF-κB and SAPK/JNK signaling cascades and the expression of the Tlr4 gene. Third, Tα1 significantly reduced p53 and the activity of the P53 gene, which is a marker of cell apoptosis. Fourth, it was shown that the increase in Ar-1 gene expression under the influence of LPS was significantly reduced using Tα1. Thus, it was found that the presence of Tα1 in the RAW 264.7 cell culture medium significantly reduced the level of the pro-inflammatory response of cells.

[Ischemia-Reperfusion Injury: Molecular Mechanisms of Pathogenesis and Methods of Their Correction].

Ischemia-reperfusion is a cascade of complex and interrelated pathological processes underlying many human diseases, including such socially significant diseases as stroke, myocardial infarction, acute renal failure, etc. The present review considers modern ideas about the main biochemical and signal-regulatory processes in the cell under conditions of ischemia-reperfusion. Both generally accepted and newly developed ways of ischemia-reperfusion lesion correction aimed at different chains of this pathological process are considered.

Protective effect of exogenous peroxiredoxin 6 and thymic peptide thymulin on BBB conditions in an experimental model of multiple sclerosis.

This study aimed to assess the effects of the immunomodulator thymulin, a thymic peptide with anti-inflammatory effects, and peroxiredoxin 6 (Prdx6), an antioxidant enzyme with dual peroxidase and phospholipase A2 activities, on the blood‒brain barrier (BBB) condition and general health status of animals with relapsing-remitting experimental autoimmune encephalomyelitis (EAE), which is a model of multiple sclerosis in humans. Both thymulin and Prdx6 significantly improved the condition of the BBB, which was impaired by EAE induction, as measured by Evans blue dye accumulation, tight-junction protein loss in brain tissue, and lymphocyte infiltration through the BBB. The effect was associated with significant amelioration of EAE symptoms. Thymulin treatment was accompanied by a decrease in immune cell activation as judged by interleukin-6, -17, and interferon-gamma cytokine levels in serum and NF-kappaB cascade activation in splenocytes of mice with EAE. Prdx6 did not induce significant immunomodulatory effects but abruptly decreased EAE-induced NOX1 and NOX4 gene expression in brain tissue, which may be one of the possible mechanisms of its beneficial effects on BBB conditions and health status. The simultaneous administration of thymulin and Prdx6 resulted in complete symptomatic restoration of mice with EAE. The results demonstrate prospective strategies for multiple sclerosis treatment.

Geldanamycin Enhances the Radioprotective Effect of Peroxyredoxin 6 in Irradiated 3T3 Fibroblasts.

The aim of the study was to evaluate the possibility of increasing the radioprotective potential of peroxiredoxin 6 (Prdx6) and its mutant form S32A by their combined use with geldanamycin (GA) for 3T3 fibroblasts irradiated with X-rays at a dose of 6 Gy. The mutant enzyme S32A, which does not have phospholipase activity, exhibits a more pronounced radioprotective activity when combined with GA. The use of this combination of radioprotective drugs completely abolishes the peak of NF-κB activity in irradiated 3T3 cells. Another transcription factor, p53, which is an indicator of the level of cell apoptosis and increases upon irradiation, is also reduced by S32A in combination with GA. The low-molecular-weight protein p21, which is a marker of cell senescence and whose production increases upon irradiation, is also normalized when S32A is used in combination with GA. In addition, the use of this combination of radioprotective drugs significantly reduces the stress response of 3T3 cells to X-ray irradiation.

Protective role of exogenous recombinant peroxiredoxin 6 under ischemia-reperfusion injury of kidney.

Peroxiredoxin 6 (Prx6) is an important antioxidant enzyme with various functions in the cell. Prx6 reduces a wide range of peroxide substrates, playing a leading role in maintaining the redox homeostasis of mammalian cells. In addition to the peroxidase activity, a phospholipase A2-like activity was demonstrated for Prx6, which plays an important role in the metabolism of membrane phospholipids. Besides that, due to its peroxidase and phospholipase activities, Prx6 participates in intracellular and intercellular signal transduction, thus triggering regenerative processes in the cell, suppressing apoptosis caused by various factors, including ischemia-reperfusion injuries. A nephroprotective effect of exogenous recombinant Prx6 administered before ischemia-reperfusion injury was demonstrated on an animal model. Exogenous Prx6 effectively alleviates the severeness of renal ischemia-reperfusion injuries and facilitates normalization of their structural and functional conditions. Infusion of exogenous Prx6 increases the survival rate of experimental animals by almost 3 times. Application of exogenous Prx6 can be an effective approach in the prevention and treatment of renal ischemia-reperfusion kidney lesions and in preserving isolated kidneys during transplantation.

Natural Dicarbonyls Inhibit Peroxidase Activity of Peroxiredoxins.

It was established that recombinant human peroxiredoxins (Prx1, Prx2, Prx4, and Prx6) inhibit natural dicarbonyls formed during free radical peroxidation of unsaturated lipids (malonic dialdehyde) and oxidative transformations of glucose (glyoxal and methylglyoxal). A possible role of the decrease in the activity of peroxiredoxins under oxidative and carbonyl stress is discussed as an important factor that triggers the molecular mechanisms of vascular wall damage in atherosclerosis and diabetes mellitus.

Enzymatic antioxidant system of endotheliocytes.

It is shown that endothelial cells from human umbilical vein have a reduced activity and gene expression of the "classic" antioxidant enzymes (Cu,Zn-superoxide dismutase, catalase, and Se-containing glutathione peroxidase). At the same time, a high expression level of peroxiredoxin genes was identified in the same endothelial cells, which obviously indicates the predominant involvement of these enzymes in protecting the endothelium from the damaging effect of free radical peroxidation.