Dipeptides Increase Functional Activity of Human Skin Fibroblasts

We analyzed the effect of dipeptide Glu-Trp and isovaleroyl-Glu-Trp in concentrations of 0.2, 2 and 20 μg/ml and Actovegin preparation on functional activity of human skin fibroblasts. Dipeptides, especially Glu-Trp, produce a stimulating effect on human skin fibroblasts and their effect is equivalent to that of Actovegin. Dipeptides stimulate cell renewal processes by activating synthesis of Ki-67 and reducing expression of caspase-9 and enhance antioxidant function of the cells by stimulating the expression of Hsp-90 and inducible NO-synthase. These findings suggest that dipeptides are promising candidates for preparations stimulating reparative processes.

Effects of Lys-Glu-Trp peptide on cell-cell interactions and vascular endothelium proliferation under normal conditions and during atherosclerosis

The molecular mechanism of atherosclerosis is based on decreased expression of signal molecules connexin (Cx37 and Cx40), vascular endothelial growth factor (VEGF), and proliferative protein Ki-67, which characterize the processes of cell-cell interactions and proliferation of vascular endotheliocytes. Lys-Glu-Trp peptide in doses of 4 and 40 μg/ml promoted recovery of Cx37, Cx40, and VEGF expression in cultured endotheliocytes from the aorta of patients with atherosclerosis, which attests to vasoprotective effects of this agent.

Short peptides stimulate serotonin expression in cells of brain cortex

Peptides Glu-Asp-Arg and Lys-Glu-Asp stimulate serotonin expression in aging cultures of brain cortex cells. Peptide regulation of 5-tryptophan hydroxylase gene encoding the enzyme involved in serotonin synthesis was demonstrated by the molecular docking method. The CCTGCC nucleotide sequence in 5-tryptophan hydroxylase gene was found to be complementary to these peptides. Hence, Glu-Asp-Arg and Lys-Glu-Asp peptides epigenetically regulate serotonin synthesis in the brain cortex, which indicates their neuro- and geroprotective activities.

[Tripeptides slow down aging process in renal cell culture]

The mechanism of geroprotective effect of peptides AED and EDL was studied in ageing renal cell culture. Peptide AED and EDL increase cell proliferation, decreasing expression of marker of aging p16, p21, p53 and increasing expression of SIRT-6 in young and aged renal cell culture. The reduction of SIRT-6 synthesis in cell is one of the causes of cell senescence. On the basis of experimental data models of interaction of peptides with various sites of DNA were constructed. Both peptides form most energetically favorable complexes with d(ATATATATAT)2 sequences in minor groove of DNA. It is shown that interaction of peptides AED and EDL with DNA is the cause of gene expression, encoded marker of ageing in renal cells.

Immunomodulating effects of Vilon and its analogue in the culture of human and animal thymus cells

We studied molecular mechanisms of immunoprotective effects of two dipeptides, AB-O and R-1, on cultured human and rat thymic cells. Both dipeptides were shown to increase the expression of lymphocyte differentiation marker CD5 in thymic cells. Dipeptide AB-O induced T-cells precursor differentiation towards CD4(+)T-helpers and its effect was weaker than that of dipeptide R-1. Dipeptide R-1 stimulates differentiation of CD5(+) cells to mature T-helpers and cytotoxic CD8(+) T cells and hence can be considered as a bioactive substance possessing immunomodulator and antiallergic activity.

[Tetrapeptide stimulates functional activity of the pancreatic cells in aging]

In this study the molecular mechanisms of pancreoprotective action of researched tetrapeptide H-Lys-Glu-Asp-Trp-NH2 in aging pancreatic cells of a human were investigated. It is established that the studied tetrapeptide increases the expression of matrix metalloproteinase MMP2, MMP9, serotonin, glycoprotein CD79alpha, antiapoptotic protein Mcl1, proliferation markers PCNA and Ki67 and decreases the expression of proapoptotic protein p53 in aged pancreatic cell cultures. Thus, the capability to activate the expression of signaling molecules--markers of functional activity of pancreatic cells lies behind the clinical effect of studied tetrapeptide observing in elderly patients with type 2 diabetes mellitus.

[Age-related features of immunocompetent cells of human placenta associated with diabetes mellitus]

The immune-competent cells of placenta play the important role in protection of developing fetus against infectious agents; but their dysfunction can lead to development of placental insufficiency that affects health both fetus and mother. The aim of this study was the comparative analysis of presence of immune competent cells in villous chorion of mature placenta, taken from women with diabetes of different age groups. In our study we found three subpopulations of immune cells in villous chorion of mature placenta: natural killer cells (NK), B-lymphocytes and macrophages. Prevailing subpopulation are macrophages, they are detected 1,8 times more often than B-lymphocytes, and 2,3 times more often than NK. The quantity of immune competent cells in groups with diabetes of various types is different. Thus, the greatest number of macrophages was detected in group with diabetes type II of middle age (29-35 years)-- 4.62 +/- 0.93%, B-lymphocytes in group of women with diabetes type I of younger age (18-28 years)--2.50 +/- 0.30%, NK-cells in group with diabetes type I of younger age--1.98 +/- 0,42%. Analysis of received data showed the differences in expression of markers of immune cells in women of different age groups, which brings about the conclusion of various reactance of immune system of women with diabetes depending on age.