LYMPH NODE REGULATORY T-CELL IN Muc2-/- MICE WITH HELICOBACTER SPP.

The immune processes associated with the formation of resistance to pathogens in the intestine depend on the microbiome. The maintenance of homeostasis in the intestine is provided by regulatory T-cells. In inflammatory bowel disease (IBD), both a disturbance of the T-regulatory function and changes in microflora are observed. Aggravation of the disease is accompanied by various infections. However, pathobionts such as Helicobacter spp., can affect regulatory T-cells. One of the genetic models for studying IBD is Muc2 knockout mice. In these mice, as in humans with IBD, intestinal epithelial and immune cells closely interact with the microflora. It is believed that the immune cells of the lymph nodes Muc2-/- mice are sensitive to changes in the microflora formed in them. In this study, the effect of Helicobacter spp. on the number and percentage of different types of leukocytes and T regulatory cells in the mesenteric lymph nodes of Muc2-/- mice was studied. The number of CD45+CD19+, CD45+CD3+, CD45+CD3+CD4+, CD45+CD3+CD8+-cells in the mesenteric lymph nodes of Muc2-/- mice was significantly higher to compare with wild-type Muc2+/+ mice. However, the presence of infection in Muc2-/- mice canceled the increase in the number of CD45+CD19+, CD45+CD3+, CD45+CD3+CD4+, CD45+CD3+CD8+-cells. In wild-type Muc2+/+ mice, infection had no significant effect on cells in mesenteric lymph nodes. This change in the decrease in immune cells in the mesenteric lymph nodes under the Helicobacter spp. may be associated with the activation of regulatory T-cells. Indeed, it has been shown that the presence of a congenital Helicobacter spp. infection increased of the number of regulatory T-cells (CD45+CD4+CD25+FoxP3+) in the mesenteric lymph nodes. Well known that regulatory T-cells mediate anti-inflammatory responses in the gut. Thus, an increase in regulatory T-cells promotes a decrease in all types of immune cells in the mesenteric lymph nodes of Muc2-/- mice infected with Helicobacter spp. It could provide an improvement in the vital functions of these mice and possibly reduces inflammatory responses in the intestine. This may indicate that some congenital pathobionts activate of the regulatory mechanisms of immunity and, thereby, have a beneficial effect on the host

Non3 is an essential Drosophila gene required for proper nucleolus assembly

The nucleolus is a dynamic non-membrane-bound nuclear organelle, which plays key roles not only in ribosome biogenesis but also in many other cellular processes. Consistent with its multiple functions, the nucleolus has been implicated in many human diseases, including cancer and degenerative pathologies of the nervous system and heart. Here, we report the characterization of the Drosophila Non3 (Novel nucleolar protein 3) gene, which encodes a protein homologous to the human Brix domain-containing Rpf2 that has been shown to control ribosomal RNA (rRNA) processing. We used imprecise P-element excision to generate four new mutant alleles in the Non3 gene. Complementation and phenotypic analyses showed that these Non3 mutations can be arranged in an allelic series that includes both viable and lethal alleles. The strongest lethal allele (Non3∆600) is a genetically null allele that carries a large deletion of the gene and exhibits early lethality when homozygous. Flies heterozygous for Non3∆600 occasionally exhibit a mild reduction in the bristle size, but develop normally and are fertile. However, heteroallelic combinations of viable Non3 mutations (Non3197, Non3310 and Non3259) display a Minute-like phenotype, consisting in delayed development and short and thin bristles, suggesting that they are defective in ribosome biogenesis. We also demonstrate that the Non3 protein localizes to the nucleolus of larval brain cells and it is required for proper nucleolar localization of Fibrillarin, a protein important for post-translational modification and processing of rRNAs. In summary, we generated a number of genetic and biochemical tools that were exploited for an initial characterization of Non3, and will be instrumental for future functional studies on this gene and its protein product

Role of the Mucin-2 and Kaiso genes in the social behavior of mice

Inflammatory processes in the gut lead to abnormal­ities in various systems of the body, in particular, to changes in the activity of the central nervous system. Although the mechanisms of these effects are not yet known, it has been demonstrated that intestinal inflammation is associated with anxiety and depression. In this work, we used an animal model of intestinal inflammation, which might result in behavioral changes. The animals used were knock-out mice with double mutations in the Kaiso and Mucin-2 genes. The Kaiso gene encodes a transcription factor that is expressed both in the brain and in the intestine. The Mucin-2 gene encodes a protein that serves as a scaffold for the synthesis of intestinal proteoglycan. Mucin-2 is a major proteoglycan of the intestinal mucus layer and performs multiple functions, including barrier and defensive ones. We used knock-out animals with a mutation in the trans­cription factor Kaiso in tests assessing social behavior, but did not observe any difference between test subjects and wild-type animals. By contrast, double knock-out animals that additionally had a mutation in Mucin-2, a major gene for intestinal proteoglycan, displayed significant changes in social behavior: lower aggression rates and higher rates of courtship behavior toward a male intruder. These results suggest that intestinal homeostasis might have a strong impact on the nervous system of the animals. It remains unclear whether the influence of the two genes is synergistic or the knock-out of the Mucin-2 gene alone determines this behavior in mice. Further investigations will help clarify the matter

Role of the Kaiso gene in the development of inflammation in Mucin-2 defcient mice

The number of people with inflammatory bowel disease (IBD) is constantly increasing worldwide. The main factors that have effects on the etiology of the disease are genetic, environmental and immunological. However, the mechanism of disease development and effective treatment of IBD have not yet been found. Animal models help address these problems. The most popular model is considered to be transgenic models in which individual genes are knocked out. One of such models for the study of IBD are mice with a null mutation of the Muc2 gene encoding the Mucin-2 protein, which is involved in the formation of a protective mucin layer in the small and large intestine. Some of transcription factors that change the expression of intestinal genes are involved in the development of IBD and colorectal cancer. One of such transcription factors is “zinc fnger” domain-containing protein Kaiso which is able to bind to methylated DNA. In this study, we assessed the role of Kaiso in the development of intestinal inflammation using the experimental model of C57BL/6Muc2-/-Kaiso-/-. We have shown that mice with impaired intestinal barrier function that develop processes similar to human IBD also develop inflammatory responses, such as increased expression of Il1, Tnf and Il17a genes. The defciency of the Kaiso transcription factor in Mucin-2 knockout mice causes a decrease in the expression level of only the Cox2 and Tff3 genes. Perhaps a decline in the expression of the gene encoding cyclooxygenase-2 can lead to a decrease in the expression of the antibacterial factor Trefoil factor 3. However, in the experimental model of IBD, Kaiso protein did not play a signifcant role in the regulation of pro-inflammatory cytokines of tumor necrosis factor and interleukins 1 and 17

Sirtuins and chemokines as markers of replicative and induced senescence of human endotheliocytes

Background. One of the factors of the pathogenesis of atherosclerosis and other cardiovascular diseases is induced endothelial senescence. In this regard, the urgent task of molecular biology and medicine is the search for molecules that affect the process of vascular endotheliocytes senescence.The aim. To assess the expression of Sirt-1,3,6 and chemokines IL-4, CXCL11 in the replicative and induced senescence of human endotheliocytes.Materials and methods. The study was conducted on the primary culture of isolated human umbilical vein endothelial cells (HUVECs). HUVECs were cultured under conditions of replicative (natural) and lipopolysaccharide induced senescence.Results. The synthesis of Sirt-1,3,6, IL-4 and CXCL11 was evaluated using western blot analysis. We revealed a decrease in Sirt-1,3,6 synthesis by 1.6–1.8 times (р < 0.05) in the conditions of HUVEC replicative senescence. Induced senescence of endotheliocytes is characterized by a more pronounced decrease (1.7–3.4 times; р < 0.05) in the Sirt-1,3,6 synthesis. CXCL11 synthesis increases by 1.4 times (р < 0.05) in replicative and by 3.4 times (р < 0.05) in induced HUVEC senescence. IL-4 synthesis increases by 4.7 times in conditions of induced HUVEC senescence and doesn’t have changes in replicative senescence of endotheliocytes.Conclusion. These data obtained indicate that sirtuins and chemokines play an important role in the development of endothelial dysfunction observed in natural and induced senescence

Features of the clinical course of infection caused by the human herpes virus type 6 in children

The purpose of the study is to determine the features of the clinical course of infection caused by the human herpes virus type 6 in children.Цель исследования — определить особенности клинического течения инфекции, вызванной вирусом герпеса человека 6 типа у детей

Role of intestinal mucin-2 in the effectiveness of the treatment of Helicobacter spp. infection in laboratory mice

Abnormal synthesis of the main intestinal proteo­glycan mucin-2 is typical of ulcerative colitis and Crohn’s disease in humans. Those morphological changes of the mucus layer affect the diversity of the intestinal microflora. Antibiotics may be ineffective or even dangerous to humans or animals deficient for mucin-2 because of the risk of sepsis and chronic inflammation. In this study, we investigated the potential of antibiotics (clarithromycin, amoxicillin, and metronidazole) in elimination of patho­genic infection from Muc2 knockout mice (Muc2–/–). We assayed the population sizes of pathogens (Heli­co­bacter spp.) and symbiotic (E. coli) bacteria in the intestines of animals as a criterion of antibiotic efficacy. The damaging effect of antibacterial treatment on the host body was estimated from their survival rate. Three antibiotics were ineffective in the elimination of Helicobacter spp. from mucin-2-deficient mice. Moreover, the mortality of Muc2 knockout mice during the antibacterial treatment was 60 %. The survival of wild-type mice (C57BL/6J) during the treatment was 100 %. The weight of wild-type mice showed no decrease during the treatment. The Helico­bacter spp. pathogen was fully eradicated from wild-type mice. Thus, therapy of Helicobacter spp. infection in mucin-2 deficient animals is not only poorly efficient but even deadly. The high susceptibility to antibiotics allows Muc2 knockout mice to be used as a test model to evaluate the pharmacological safety of new antibiotics

Association of genotypes of cows of the Kholmogory breed by beta-casein with milk productivity

The aim of the study is to identify the frequency of occurrence of various allelic variants and genotypes of beta-casein in cows of the Kholmogory breed and their relationship with dairy productivity. The tasks of the research are genotyping of cattle of the Kholmogory breed by the beta-casein locus and establishing its connection with qualitative and quantitative indicators of dairy productivity. As the objects for the research there were taken 150 cows of the 1st, 2nd and 3rd lactation. An allele-specific variant of the PCR method (AS-PCR) was used to identify A1 and A2 beta-casein. As the result it had been established that in the studied part of the herd, 23 % of animals had the A2A2 genotype, 43 % of animals had the A1A1 genotype and 34 % of animals had the A1A2 genotype. For 100 days of the first lactation, animals with A1A2 genotype showed the highest value in milk yield. Animals with A2A2 genotype for 305 days of lactation had the highest milk yield and the amount of milk protein, however, the difference was not statistically significant compared to the animals with A1A2 genotype. Genotype A1A1 has lower indicators by all the parameters studied, with a significant difference relative to genotypes A1A2 and A2A2. Thus, the study of CSN2 is a promising area of scientific research, and the results of the study of beta-casein genotypes can be used as a marker selection in improving the herds of the Kholmogory breed