Volume 57, Nº 4 (2023)

Endothelial cells (ECs), which form the inner surface of the blood vessels, contact with blood, withstand mechanical pressure, and demonstrate heterogeneous reactions to exogenous and endogenous stimuli. ECs have unique properties in accordance with their niche, and play an important role in regulating vascular homeostasis. Endothelial cells may undergo a dynamic phenotypic switch in terms of its heterogeneity, which may lead to endothelial dysfunction and a number of associated pathologies. Endothelial-mesenchymal transition (EndMT) is one of the possible molecular and cellular mechanisms of such kind. EndMT is characterized by phenotypic changes in ECs through which the cells obtain new properties, i.e. start producing mesenchymal markers such as alpha-SMA and vimentin, change morphology, and become able to migrate. EndMT is a complex biological process, which may be induced by inflammation, hypoxia or oxidative stress, and be involved in pathogenesis of cardiovascular disease. This manuscript presents the key markers, inhibitors, inducers of endothelial-mesenchymal transition, and overall state-of-the-art of EndMT in cardiovascular diseases.

5-Methyl-2'-deoxycytidine (mC) at CpG sites plays a key role in the epigenetic gene function regulation, cell differentiation and carcinogenesis. Despite the importance of mC for normal cell function, CpG dinucleotides are known as mutagenesis hotspots. mC is deaminated with the formation of T, causing C→T transitions. However, several recent studies demonstrated the effect of epigenetic modifications of C on the fidelity and efficiency of DNA polymerases and excision repair enzymes. This review summarizes the known data indicating the existence of mutagenesis mechanisms independent of deamination at CpG sites.

The study of the past through the analysis of ancient DNA allows us to solve scientific problems related to the genogeographic origin and patterns of population migration. The Khazar Khaganate is a subject of controversy among scientists in various fields of science: its complex historical formation, the lack of a sufficient number of artistic and written sources, together with the disappearance of representatives of the Khazar culture, leaves open the question of the appearance of the Khazars. In this work, DNA-phenotyping of bone remains from the elite burials of the South of Russia of the Khazar period was carried out on the basis of the color of eyes, hair, skin, and blood groups according to the AB0 system. It was established that 8 out of 10 buried had brown eyes, dark hair (to varying degrees), and predominantly dark skin during their lifetime. People from two burials had gray-blue eyes, and one person had blond hair. In 8 individuals, the most probable blood type was established according to the AB0 system: 5 people had 0 (I) group, 4 people had A (II) group and one B (III). Assessment of allele distribution of ten autosomal markers with population specificity indicates high heterogeneity of ethnogeographic origin of the studied Khazars. The obtained results are evidence of the ethnocultural, genetic and phenotypic diversity of the Khazar Khaganate.

Atherosclerosis is characterized by excessive uptake of cholesterol-rich low-density lipoproteins by the vascular wall macrophages. It leads to macrophage transformation into foam cells, accumulation of lipids in the intima of the arteries, atherosclerotic plaques development and following progression of cardiovascular diseases. Adiponectin, adipose tissue adipokine, has anti-atherogenic and anti-inflammatory effects that are mediated through binding to its receptors – AdipoR1 and AdipoR2. One of the mechanisms of adiponectin anti-atherogenic activity may be the participation in the regulation of reverse cholesterol transport and prevention of foam cells formation. We assumed that AdipoRon, a small-molecule adiponectin receptor agonist, could modulate the reverse cholesterol transport and inflammation genes expression in human macrophages. The aim of the present study was to investigate the effect of various concentrations of AdipoRon on the lipid metabolism ABCA1, ABCG1, APOA1, NR1H3 (LXRα), NR1H2 (LXRβ), PPARG, ACAT1 genes expression and inflammation IL6, TNFA, TLR4 genes expression in human macrophages. Primary human macrophages and THP-1 macrophages cell line were treated with various concentrations of AdipoRon. Cell viability was measured using the MTS assay. ABCA1, ABCG1, APOA1, NR1H3, NR1H2, PPARG, ACAT1, IL6, TNFA, TLR4 mRNA levels in the primary human macrophages was assessed using real-time PCR. The increase of PPARG and ABCA1 mRNA levels was shown in the primary human macrophages after 5 and 10 μM A-dipoRon treatment for 24 h. At the same time high concentration (20 μM) of AdipoRon has cytotoxic effect on macrophages, especially, on THP-1 cell line. The effect of AdipoRon on human macrophages and the investigation of potential adiponectin receptor agonists is of interest, due to the search for new approaches to the prevention and treatment of atherosclerosis.

The status of DNA methylation in the human genome changes during the pathogenesis of common diseases and acts as a predictor of life expectancy. Therefore, it is of interest to investigate the methylation level of regulatory regions of genes responsible for general biological processes that are potentially significant for the development of age-associated diseases. Among them there are genes encoding proteins of DNA repair system, which are characterized by pleiotropic effects. Here, results of the targeted methylation analysis of two regions of the human genome (the promoter of the MLH1 gene and the enhancer near the ATM gene) in different tissues of patients with carotid atherosclerosis are present. Analysis of the methylation profiles of studied genes in various tissues of the same individuals demonstrated marked differences between leukocytes and tissues of the vascular wall. Differences in methylation levels between normal and atherosclerotic tissues of the carotid arteries were revealed only for two studied CpG sites (chr11:108089866 and chr11:108090020, GRCh37/hg19 assembly) in the ATM gene. Based on this, we can assume the involvement of ATM in the development of atherosclerosis. “Overload” of the studied regions with transcription factor binding sites (according to ReMapp2022 data) indicate that the tissue-specific nature of methylation of the regulatory regions of the MLH1 and ATM may be associated with expression levels of these genes in a particular tissue. It has been shown that inter-individual differences in the methylation levels of CpG sites are associated with sufficiently distant nucleotide substitutions.

All-trans retinoic acid (ATRA) in acute promyelocytic leukemia (APL) has been the most famous differentiation induction therapy during which the expression of PU.1, a key transcription factor (TF) for myeloid lineage determination in normal hematopoiesis is restored. In our previous studies, we found a stress-inducible H3K27 demethylase, JMJD3, to directly upregulate PU.1 expression to promote myeloid commitment during normal myelopoiesis. In addition, JMJD3 acts as an oncorepressor and plays a critical regulatory role in the initiation and progression of malignant hematopoiesis. In this study, we further resolved the relationship between JMJD3 and PU.1 in APL therein JMJD3 exerts oncorepressor activity via promoting PU.1 expression.

MicroRNAs are small non-coding regulatory RNAs about 22 nt long, post-transcriptional and transcriptional regulators of gene expression that stabilize the cellular phenotype and play an important role in differentiation, development, and apoptosis. MicroRNA biogenesis includes several precisely controlled post-transcriptional stages of processing and transport, including cytoplasmic cleavage of pre-miRNA by type III ribonuclease DICER with the formation of a mature duplex included in the RISC complex. The role of miRNA and its biogenesis are not well understood in such an important process as cellular stress. Cellular stress is a non-specific cellular response to non-physiological stimuli that can switch a cell to death or cellular senescence. The global decrease in microRNA levels is a key feature of cancer cells and an important reason for the formation of a malignant phenotype. In this work, using flow cytometry and high-throughput analysis of gene expression, we showed that chronic endoplasmic reticulum (ER) stress, one of the types of cellular stress associated with impaired protein folding in the ER, leads to the formation of a cellular aging phenotype in fibroblast-like FRSN cells. Despite the fact that acute ER stress can reduce miRNA biogenesis, chronic stress does not lead to a significant drop in global miRNA expression and is accompanied by only a slight decrease in DICER1 mRNA expression. Under chronic ER stress, we found an increase in cell population heterogeneity in terms of lysosomal beta-galactosidase activity, which does not exclude induced or initial cell heterogeneity and in terms of expression of microRNA biogenesis pathway components.

Ras proteins are small GTPases and function as molecular switches to regulate cellular homeostasis. Ras-dependent signalling pathways regulate several essential processes such as cell cycle progression, growth, migration, apoptosis, and senescence. The dysregulation of Ras signaling pathway has been linked to several pathological outcomes. A potential role of RAS in regulating the redox signalling pathway has been established that includes the manipulation of ROS levels to provide a redox milieu that might be conducive to carcinogenesis. Reactive oxygen species (ROS) and mitochondrial impairment have been proposed as major factors affecting the physiology of cells and implicated in several pathologies. The present study was conducted to evaluate the role of Ras1, tert Butyl hydroperoxide (tBHP), and antimycin A in oxidative stress response in Schizosaccharomyces pombe cells. We observed decreased cell survival, higher levels of ROS, and mitochondrial dysfunctionality in ras1Δ cells and tBHP as well as respiratory inhibitor, antimycin A treated wild type cells. Furthermore, these defects were more profound in ras1Δ cells treated with tBHP or antimycin A. Additionally, Ras1 also has been shown to regulate the expression and activity of several antioxidant enzymes like glutathione peroxidase (GSH-Px), glutathione-S-transferase (GST), and catalase. Together, these results suggest the potential role of S. pombe Ras1 in mitigating oxidative stress response.

Hepatocellular carcinoma (HCC) is the most frequently diagnosed primary liver tumor worldwide. Tumor-associated macrophages (TAMs) usually have a similar phenotype to M2-like macrophages and can participate in tumor progression by secreting cytokines to suppress the immune response of tumor-infiltrating lymphocytes. We investigated the role of M2 macrophages in HCC progression and explored the effects of vascular endothelial growth factor receptor 2 inhibitor – apatinib . As a cellular model of HCC, Hepb3 cell line was used. M2 macrophages were obtained by differentiation of THP-1 cells. The Transwell chamber was used to co-culture M2 macrophages and Hepb3 cells. CCK-8 assay and EdU assay were conducted to measure cell viability and proliferation capacity. Transwell migration assay was conducted to estimate cellular metastatic potential. Cytokine expression levels were assessed by ELISA. Western blot was used to quantify the activation of the VEGFR2/STAT3/PD-L1 axis. It has been shown that co-culture with M2 macrophages increased, proliferation, viability, cytokine production, invasion, and migration of Hepb3 cells. The secretion of TGF-β1, IL-6, MMP-9, and VEGF was significantly increased after co-culture. Apatinib suppressed M2 macrophage-induced proliferation, cell viability, invasion, and migration of Hepb3 cells. Moreover, apatinib remarkedly decreased expression levels of p-VEGFR2, p-STAT3, and PD-L1 in Hepb3 cells under the co-culture conditions. In conclusion, apatinib treatment could suppress TAMs-mediated cancer cell behaviors of HCC cells via modulation of the VEGFR2/STAT3/PD-L1 signaling pathway.

Helicobacter pylori (H. pylori) infection can cause persistent inflammatory response in human gastric mucosal epithelial cells, which may result in the occurrence of cancer. However, the underlying mechanism of carcinogenesis has not been elucidated yet. Herein, we established the models of chronic H. pylori infection in GES-1 cells and C57BL/6J mice. Interleukin 8 (IL-8) level was detected by ELISA. The expression of NF-κB p65, IL-8, Wnt2 and β-catenin mRNA and proteins was evaluated by real-time PCR, Western blotting, immunofluorescence staining, and immunohistochemistry. The infection of H. pylori in mice was evaluated by rapid urease test, H&E staining and Warthin‒Starry silver staining. The morphological changes of gastric mucosa were observed by electron microscopy. Our results showed that in H. pylori infected gastric mucosal cells along with activation of NF-κB signaling pathway and increase of IL-8 level, the expression of Wnt2 was also increased significantly, which preliminarily indicates that IL-8 can positively regulate the expression of Wnt2. Studies in chronic H. pylori infected C57BL/6J mice models showed that there was an increased incidence of premalignant lesions in the gastric mucosa tissue. Through comparing changes of gastric mucosal cell ultrastructure and analyzing the relationship between NF-κB signaling pathway and Wnt2 expression, we found that H. pylori infection activated NF-κB signal pathways, and the massive release of IL-8 was positively correlated with the high expression of Wnt2 protein. Subsequently, the activated Wnt/β-catenin signal pathways may be involved in the malignant transformation of gastric mucosal cells. Collectively, H. pylori chronic infection may continuously lead to persistent inflammatory response: activate NF-κB pathway, promote IL-8 release and thereby activate Wnt/β-catenin pathway. IL-8 probably plays an important role of a linker in coupling these two signal pathways.

Enzymatic methylatransferase reactions are of crucial importance for cellular metabolism, and S-adenosyl-L-methionine is the main donor of the methyl group. DNA, RNA, proteins, and low-molecular-weight compounds are the substrates of methyltransferases. In mammals, methylation of the C5 position of cytosine residues in CpG sequences in DNA is performed de novo by DNA methyltransferase Dnmt3a. “Methylation pattern” is one of the factors determining the epigenetic regulation of gene expression. In the present work, we investigated the interaction of phosphonous and phosphonic analogues of S-adenosyl-L-methionine and S-adenosyl-L-homocysteine with the catalytic domain of Dnmt3a. The phosphonous and phosphonic analogs of S-adenosyl-L-methionine were shown to be substrates of Dnmt3a, and the efficiency of the methylation was only two times less than that of natural S-adenosyl-L-methionine. Both phosphorus-containing analogs of S- adenosyl-L-homocysteine, a natural methyltransferase inhibitor, exhibited similar inhibitory activity against Dnmt3a and were approximately four times less active than S-adenosyl-L-homocysteine. The activities of the phosphonous and phosphonic analogs turned out to be close that was quite unexpected, since the geometry and charge of the phosphorus-containing groups differ significantly. The possibilities of using phosphorus-containing analogs of S- adenosyl-L- methionine and S-adenosyl-L-homocysteine as promising tools for the investigation of methyltransferases are discussed.

Ctenophore Mnemiopsis leidyi A. Agassiz, 1865 responds to gentle mechanical stimulation with intense luminescence; however, the mechanism of this phenomenon is unknown. We searched for possible mechanosensitive receptors that initiate signal transduction resulting in photoprotein luminescence. The three ortholog genes of mouse (5z96) and Drosophila (5vkq) TRPC-proteins, such as ML234550a-PA (860 aa), ML03701a-PA (828 aa) and ML038011a-PA (1395 aa), were found in the M. leidyi genome. The latter protein contains a long ankyrin helix consisting of 16 ANK domains. Study of the annotated domains and the network of interactions between the interactome proteins suggests that the ML234550a-PA and ML03701a-PA proteins carry out cytoplasmic, but ML038011a-PA provides intranuclear transduction of mechanical signals. Spatial reconstruction of the studied proteins revealed differences in their structure, which may be related to various functions of these proteins in the cell. The question of which of these proteins is involved in the initiation of luminescence after mechanical stimulation is discussed.