Vol 13, No 4 (2019)

A new nonimmortalized mesenchymal stem cell (MSC) line from human epicardial adipose tissue (ADH–MSC) of a 50-year-old donor in the process of coronary artery bypass has been characterized. In the process of long-term cultivation (passages 8-16), the proportion of senescent cells gradually increases. According to the β-galactosidase activity, the number of senescent cells by passage 16 reached 66%. By this time, other signs indicate the onset of the active phase of replicative senescence: increased cell size and spreading, declined cloning efficiency and proliferation rate, increased the cell population doubling time. These results confirm the limited lifespan of ADH–MSC cells that is common for nonimmortalized cell populations. The karyotypic analysis showed, that at the eighth passage, the cells had normal human karyotype. By passage 12, the karyotypic heterogeneity became substantially increased, and by passage 16 it exceeded the permissible level of chromosomal disorders in normal MSCs. The formation of novel structural karyotype variants (SVK) was shown. The predominant participation of the short arm of one of the homologues of chromosome 21 in clonal and nonclonal rearrangements, as well as in dicentrics by the type of telomeric associations, was found. At passages 8 and 16, the cells exhibited high expression of surface antigens characteristic for human MSCs (CD44, CD73, CD90, CD105, HLA–ABC) and an absence of CD34, CD45, and HLA–DR expression. At the eighth passage, there was a significant expression of SSEA-4, a marker of early ESC differentiation. Its expression significantly reduced at passage 16. At passages 8–16, ADH–MSC cells were able to differentiate equally in the osteogenic and chondrogenic directions. The cell capacity for adipogenic differentiation decreases by passage 16. Collectively, our results show that the MSC cell line demonstrated significant changes in the process of early replicative senescence, possibly related to the altered microenvironment for the cells of the donor with heart disease. Early senescence and karyotypic instability may be associated with more significant impairment of the DNA repair system of ADH–MSC cells compared to other lines.

CAY10603 (CAY) is an effective inhibitor of HDAC6 histone deacetylase involved in α-tubulin deacetylation for murine fibroblasts transformed with E1A and cHa-ras oncogenes. In low concentrations, CAY blocks the cell cycle of the G₁/S phase of these cells and slows down their proliferation, but does not provoke apoptotic death. CAY treatment in combination with sodium butyrate generates accelerated senescence of E1A + cHa-ras-transformants. In murine fibroblasts transformed by oncogenes of E1A and cHa-ras CAY is an efficient inhibitor of histone deacetylase HDAC6 in relation to α-tubulin as its substrate. The G₁/S cell cycle block takes place at low concentrations of CAY in these cells. Their proliferation slows down, but apoptotic death is not provoked. CAY exposure also results in the accumulation of autophagic vacuoles and autophagosome protein LC3 in the cytoplasm of E1A + cHa-ras cells that can manifest participation of HDAC6 in autophagy induction in these transformed cells.

Influenza A virus and secondary bacterial infection may have remote effects in the form of cardiovascular complications or fibrosis in different organs. However, the mechanisms governing the development of complications remain poorly studied. The present work reports the comparative assessment of the functional changes which take place in human ECV-304 endothelial cell sublines obtained previously by the long-term culturing of cells after exposure to varying infectious doses (IDs) of influenza A virus, and/or bacterial lipopolysaccharide (LPS). It has been demonstrated that, in the course of long-term culturing (six passages) after exposure to pathogenic agents (influenza virus and/or LPS), endothelial cells maintain changes in their migratory activity, permeability, and expression of mRNA for cytokines TNFα and TGFβ (along with the changes in their proliferation activity, which has been demonstrated earlier). The pattern of changes depended on the type of the agent (agents) to which the cells were exposed. The differences in migratory activity (which was at its maximum 4 h after wounding) between the cell sublines at the sixth passage correlated with the differences in their proliferation activity at the first passage (proliferation data were obtained previously). In particular, an increase in migration and proliferation was observed in the sublines exposed to low virus doses (ECV-1ID), as well as exposed to LPS (ECV-LPS), while the suppression of migration and proliferation was observed in the subline exposed to high virus doses (ECV-1000ID). In the ECV-1ID, ECV-LPS, and most notably in ECV-1ID + LPS sublines, we detected an increase in the expression of mRNA for cytokines TNFα and TGFβ, which, however, didn’t lead to the induction of apoptosis. We have also demonstrated an increase in cell permeability in the analyzed sublines, which was indicated by a decrease in the expression of the mRNAs for the genes encoding occludin and ZO-1, the tight junctions proteins . This paper also reports an evaluation of the effects of the antiviral preparations rimantadine and alpisarin on the functional state of cell sublines. As a result, it has been demonstrated that these drugs may be able to prevent the development of the pathological changes caused by influenza A virus and/or LPS in endothelial cells. The results obtained in the present work may be of use when studying the mechanisms of development of the influenza A virus and secondary bacterial infection complications.

Dexamethasone, as well as other synthetic glucocorticoids, is widely employed in general obstetric practice. The principal indication for glucocorticoid treatment is a risk of miscarriage. However, certain data suggest that glucocorticoid administration during pregnancy may lead to aberrations of brain development and behavior in the offspring. Current research suggests that such aberrations are frequently mediated by epigenetic mechanisms. The goal of the present work was to investigate the patterns of histone H3 acetylation at lysine 24 (acH3K24) in neurons of the hippocampus and the neocortex of adult rats following administration of dexamethasone (0.8 mg/kg) in the beginning and the end of week 3 of their prenatal development. Immunohistochemical analysis was used to describe changes in the acH3K24 content in the cells of the hippocampus and the neocortex of adult rats after exposure to dexamethasone on gestation days 14–16 and 17–19. The principal differences concerned the number of cells strongly stained with acH3K24-specific antibodies. In particular, exposure to dexamethasone led to a decrease in the number of cells with a high acH3K24 content in the CA1 field and the dentate gyrus of the hippocampal formation, Specifically, this decrease constituted 53.5 and 76% in CA1 and 39.7 and 87.8% in the dentate gyrus following dexamethasone administration on gestation days 14–16 and 17–19, respectively. In cortical layer 5, the abundance of acH3K24 decreased (to 55% of the control level) following dexamethasone administration on gestation days 17–19, but not on days 14–16. The observed modifications of the epigenetic status of brain cells of rats exposed to dexamethasone may underlie the long-lasting changes in behavior and learning capacity described in our previous studies.

This article presents the results of comparative studies of the frequency and distribution of chiasmata in pollen mother cells (PMCs) in five diploid tomato species, Solanum lycopersicum, S. pimpinellifolium, S. peruvianum, S. habrochaites, and S. neorickii, and one autotetraploid species, S. pimpinellifolium. It was established that under the same growing conditions, the total chiasma frequency in the cell depended on the species. At the same time, the green-fruited species S. peruvianum, S. neorickii, and S. habrochaites differed in distal chiasma frequency, while the red-fruited species S. lycopersicum and S. pimpinellifolium differed in interstitial chiasma frequency. It was shown that the total chiasma frequency in PMCs of plants of one species is a stable index of recombination potential that does not depend on the growing conditions. The redistribution between distal and interstitial chiasmata was found to be more variable, depending on the species, year, geographic growth conditions. In autotetraploid, the chiasma frequency per bivalent was lower than that in diploid S. pimpinellifolium plants, primarily due to interstitial chiasmata, the frequency of which remained at the level characteristic for diploid plants. It was concluded that the recombination plasticity of the tomato genomes was due to the redistribution of chiasmata along bivalents, and not to the change in their number in the cell.