STIMULATING EFFECT OF HIGH DOSE HEPARIN ON MIGRATION ACTIVITY AND MSC STEMNESS PRESERVATION IN THE PRESENCE OF BONE-SUBSTITUTING MATERIALS

Synthetic materials used in regenerative medicine, upon implantation, induce the development of an inflammatory reaction necessary for the effective regeneration of damaged bone tissue. Implant contact with tissues is accompanied by the deposition of blood proteins and interstitial fluid on its surface, contributing to the activation of the complement system, components of innate immunity, initiating coagulation hemostasis, leading to the formation of a fibrin clot. An extracellular matrix based on fibrin, collagen and elastin forms on the implant’s surface, which provides the basis for the formation of tissue structure through the adhesion of stem cells to the forming bone callus before the formation of bone regenerate. To prevent the development of postoperative pathological conditions caused by hypercoagulable syndrome, therapeutic strategies are used to use anticoagulants (heparin, warfarin). However, their use limits the normal formation of a fibrin clot in vivo. This can slow down the migration of mesenchymal stem cells (MSC) and disrupt the formation of callus, inhibiting the processes of osseointegration of the implant and bone healing. The study’s goal was to study the effect of heparin in a gradient of low and high concentrations on the migration activity and stem capacity of human MSCs under in vitro cultivation conditions. According to the results of flow cytometry, it was revealed that high concentrations of heparin (130, 260 IU/ml) in a 2D cultivation model contribute to an increase in the number of cells expressing surface markers CD73 and CD90, which indicates that MSCs retain high clonogenic potential. A 3D model of in vitro cultivation with the addition of heparin and osteosubstituting implants bearing a CF coating with a roughness index of Ra = 2.6-4.9 μm contributed to preserving the “stemness” character of MSCs through the expression of surface markers CD73 and CD90. According to the results obtained using the xCELLigence system, heparin at a later time (from 20-40 hours) increases the invasion of MSCs through micropores that simulate the state of the blood vessel walls. However, in the presence of HAP nanoparticles that mimic the remodeling processes of the mineral bone matrix and/or resorption of bone cement, the effect of heparin was less pronounced. The results can be used in the field of regenerative medicine associated with the introduction of MSCs. The data can serve as a prerequisite for developing new therapeutic strategies for surgical patients with a high risk of postoperative thrombosis after osteosynthesis

THE ROLE OF PREGNANCY-SPECIFIC GLYCOPROTEIN IN REGULATION OF MOLECULAR GENETIC DIFFERENTIATION MECHANISMS OF IMMUNE MEMORY T CELLS

The role of pregnancy-specific β1-glycoprotein (PSG) in the regulation of molecular genetic factors determining the functional activity of naїve T cells and T cells of immune memory in vitro was studied. Human PSG was isolated with a proprietary immuno-purification method using a biospecific sorbent followed by removing of immunoglobulin contamination with a HiTrapTM Protein G HP column. Physiological concentrations of PSG were used in the experiments. They corresponded to PSG levels in the peripheral blood of pregnant woman: 1, 10 and 100 μg/ml (I, II, III trimester, respectively). The objects of study were monocultures of naїve T cells (CD45RA+) and memory T cells (CD45R0+), obtained by immunomagnetic separation from the peripheral blood of women of reproductive age.It was established that at the level of naїve T cells (CD45RA+) PSG inhibited the expression of CD28 (1, 10, 100 μg/ml) and CD25 (100 μg/ml), without affecting the interleukin-2 (IL-2) production by these cells. At the same time, PSG in all concentrations studied suppressed the expression of CD25 at the immune memory T-cell (CD45R0+) surface but increased the IL-2 production. Expression of U2af1l4, Gfi1, hnRNPLL genes regulating the alternative splicing of the Ptprc gene encoding CD45 was also evaluated. It was found, that PSG reduced the expression of the Gfi1 (1, 10, 100 μg/ml), hnRNPLL (10, 100 μg/ml) genes, but increased the expression of the U2af1l4 gene (1, 10, 100 μg/ml) in the naїve T cells. It was shown that at the immune memory T-cells’ level the effects were similar, with PSG rendering them in all concentrations used. The revealed changes in the mRNA transcription of U2af1l4, Gfi1 and hnRNPLL genes in the studied T cell subsets may lead to the inhibition of CD45 “mature” isoform formation – CD45R0.Thus, PSG reduces the functional activity of naїve T cells and immune memory T cells associated with the expression of costimulation/activation molecules CD25 and CD28 and is involved in the regulation of Ptprc gene alternative splicing, which determines the ratio of CD45 molecule variants. Apparently, using these mechanisms, PSG regulates the functional activity of the memory T cell circulating pool, which is potentially capable of carrying out antigen-specific cytotoxic reactions against fetal antigens in vivo. In general, the data obtained broadens the notion of the PSG role in the regulation of molecular-genetic mechanisms of naїve T cells and immune memory T cells differentiation

Significance of nutrient media choice for the long-term cultures of leukemic T-lymphoblasts

Correct choice of nutrient media for culturing different types of cells in various applications is one of the most important aspects of modern biotechnology, since chemical composition of the culture media largely contains the necessary metabolites to support certain cells’ growth lines outside the body. Jurkat line of human leukemic T-lymphoblast-like cells (hereinafter Jurkat T-cells) is actively used for in vitro modeling of intracellular signaling and activation of normal blood T-lymphocytes mediated by the T-cell receptor/CD3/ CD4 complex in toxicological studies of immune and secretory responses, to test medicinal substances and ions. Also, Jurkat T-cells are widely used for ex vivo testing in immunology, oncology, toxicology, orthopedics, and traumatology. The existing standards and numerous studies are mainly based on short-term in vitro cultivation of Jurkat T-cells in RPMI 1640 nutrient medium. Meanwhile, the issues of long-term maintenance of the growth of Jurkat T-cells culture are poorly presented in the research literature. This study aimed for studying the activity of Jurkat T-cells over 7 to 14 days of in vitro culture and comparing the relative value of RPMI 1640 and αMEM media for the behavior of immunocompetent tumor cells. Using flow cytometry, multiplex analysis, and phase contrast Cell-IQ microscopy, the proportions of living cells and those dying by apoptosis and necrosis, secretion of cytokines and chemokines, and the dynamics of cell biomass propagation were studied. It was found that the αMEM medium in the complete nutrient medium, as compared with RPMI 1640, is more appropriate to in vitro promotion of cell viability (increased proportion of viable cells by 13.5% at the day 14), their secretory ability for 23 из 27 tested biomolecules, shortened adaptation time (на 32%) in culture before growth initiation, 5-fold increase of the Jurkat Т-cell cellularity by the day 7. Potential significance of the chemical components of nutrient media and secreted biomolecules for these results is discussed. As based on the results obtained, we concluded on superior properties of αMEM medium for long-term in vitro cultures of Jurkat T-cells. Consequently, the in vitro testing of medical devices intended for long-term contact with the body, including those for cancer patients, using Jurkat T-cell leukemia line in RPMI 1640 medium, may lead to wrong predictions on their biocompatibility and potential antitumor activity

Клеточные реакции CD3+ CD4+ CD45RO+ Т-лимфоцитов на дексаметазон в норме и при ревматоидном артрите в системе in vitro

The aim of the study was to analyze the influence of glucocorticoid (GC) dexamethasone (Dex) on changes in CD4+ T-cells expressing the surface molecule of activation (CD25, CD71, HLA-DR and CD95) and their ability to produce proinflammatory mediators in cultures of TCR-stimulated CD3+CD45RO+ T-lymphocytes obtained from healthy donors and patients with rheumatoid arthritis in vitro.Materials and methods. The study included 50 patients and 20 healthy donors. T-cell cultures (CD3+ CD45RO+) were obtained from mononuclear leukocytes of immunomagnetic separation (MACS® technology). As an activator of T-lymphocytes, antibiotic particles with biotinylated antibodies against CD2+, CD3+, CD28+, which simulate the process of costimulation of T cells by antigen-presenting cells, were used. The following concentrations of dexamethasone (2, 8, 16, 32, 64 mg) were used in the experiment. The change in the immunophenotype of T-lymphocytes was analyzed by flow cytofluoometry. The secretion of CD3+CD45RO+ T-cells of proinflammatory cytokines IL-2, IFNγ, TNFα, IL-17 and IL-21 was evaluated by enzyme-linked immunosorbent assay.Results. The general suppressor effect of Dex on CD3+CD45RO+ T-cell cultures mediated by a decrease in the number of CD4 + T cells expressing activation molecules (CD25) and proliferation (CD71), as well as inhibition of the production of inflammatory mediators: IFNγ, IL-2 and TNFα. It is shown that against the background of TCR activation Dex increases the number of CD4+CD95+HLA-DR+ cells in CD3+CD45RO+ cultures obtained from RA patients and does not change their content in the control. The correlations between the number of proinflammatory factors (IL-17, IL-21 and TNFα) in CD4+CD45RO+CD95+HLA-DR+ T cells in supernatants of cell cultures in RA patients indicate the presence of a pro-inflammatory potential of this population of T cells. We assume that the resistance of CD4+CD45RO+CD95+HLA-DR+ T cells in RA patients to the suppressor effect of GC generally leads to the preservation and enhancement of the functionality of autoreactive cells in the pathogenesis of RA. Целью исследования явился анализ влияния глюкокортикоида (ГК) дексаметазона (Dex) на изменение числа CD4+ Т-клеток, экспрессирующих поверхностные молекулы активации (CD25, CD71, HLA-DR и CD95), и их способности продуцировать провоспалительные медиаторы в культурах TCRстимулированных Т-лимфоцитов CD3+CD45RO+, полученных у здоровых доноров и больных ревматоидным артритом (РА), в системе in vitro. В исследование включены 50 больных и 20 условно здоровых доноров.Материал и методы. Культуры T-клеток (CD3+CD45RO+) получали из мононуклеарных лейкоцитов методом иммуномагнитной сепарации (технология MACS®). В качестве активатора Т-лимфоцитов использовали антибиотиновые частицы с биотинилированными антителами против CD2+, CD3+, CD28+ человека, имитирующие процесс костимуляции Т-клеток антиген-презентирующими клетками. В эксперименте использованы следующие концентрации дексаметазона – 2; 8; 16; 32; 64 мг. Методом проточной цитофлуориметрии проанализировано изменение иммунофенотипа Т-лимфоцитов; иммуноферментным анализом оценена секреция Т-клетками CD3+CD45RO+ провоспалительных цитокинов: IL-2, IFNγ, TNFα, IL-17 и IL-21.Результаты. Подтвержден общий супрессорный эффект Dex на культуры Т-клеток CD3+CD45RO+, опосредованный снижением числа Т-клеток CD4+, экспрессирующих молекулы активации (CD25) и пролиферации (CD71), а также угнетением продукции медиаторов воспаления: IL-2, IFNγ и TNFα. Показано, что на фоне TCR-активации Dex повышает число клеток CD4+CD95+HLA-DR+ в культурах СD3+CD45RO+, полученных от больных РА, и не изменяет их содержание в контроле. Корреляции между числом Т-клеток CD4+CD45RO+ CD95+HLA-DR+ с уровнем провоспалительных факторов (IL-17, IL-21 и TNFα) в супернатантах клеточных культур у больных РА свидетельствуют о наличии провоспалительного потенциала этой популяции Т-клеток. Предполагается, что резистентность Т-клеток CD4+CD45RO+CD95+HLA-DR+ больных РА к супрессорному действию ГК в целом приводит к сохранению и усилению функциональных возможностей аутореактивных клеток в патогенезе РА.

Human Mesenchymal Stem Cells as a Carrier for a Cell-Mediated Drug Delivery

A number of preclinical and clinical studies have demonstrated the efficiency of mesenchymal stromal cells to serve as an excellent base for a cell-mediated drug delivery system. Cell-based targeted drug delivery has received much attention as a system to facilitate the uptake a nd transfer of active substances to specific organs and tissues with high efficiency. Human mesenchymal stem cells (MSCs) are attracting increased interest as a promising tool for cell-based therapy due to their high proliferative capacity, multi-potency, and anti-inflammatory and immunomodulatory properties. In particular, these cells are potentially suitable for use as encapsulated drug transporters to sites of inflammation. Here, we studied the in vitro effects of incorporating synthetic polymer microcapsules at various microcapsule-to-cell ratios on the morphology, ultrastructure, cytokine profile, and migration ability of human adipose-derived MSCs at various time points post-phagocytosis. The data show that under appropriate conditions, human MSCs can be efficiently loaded with synthesized microcapsules without damaging the cell’s structural integrity with unexpressed cytokine secretion, retained motility, and ability to migrate through 8 ?m pores. Thus, the strategy of using human MSCs as a delivery vehicle for transferring microcapsules, containing bioactive material, across the tissue–blood or tumor–blood barriers to facilitate the treatment of stroke, cancer, or inflammatory diseases may open a new therapeutic perspective

Моделирование микроокружения мезенхимных стволовых клеток как перспективный подход к тканевой инженерии и регенеративной медицине (краткий обзор)

One of the promising areas is the design and modification of materials for control over the fate of multipotent mesenchymal stromal cells (MMSCs) that will allow stroma of various human and animal organs and tissues to be constructed. However, the discussion about the existence and functioning of microenvironment for the MMSCs is just beginning to develop. The design of artificial materials that are able to reproduce biomimetically the cellular and tissue microenvironment and based on ideas and main elements borrowed from wildlife is current direction in a development of medical materials technology and tissue bioengineering. Scaffold technology is a promising experimental approach to simulate the properties of natural microenvironment of stem cells. Our aim is a short review of key elements of MMSC microterritories, its advanced investigations and the attempts of modeling in application to tissue bioengineering and regenerative medicine.Одним из перспективных направлений являются разработка и модификация материалов для контроля жизнедеятельности мультипотентных мезенхимных стромальных клеток (ММСК), которые (ре)конструируют строму различных органов и тканей человека и животных. Тем не менее обсуждение вопроса о существовании и функционировании микроокружения ММСК только начинается. Это тормозит дальнейшее развитие клеточной биологии и тканевой инженерии. Дизайн искусственных материалов, способных к биомиметическому воспроизведению клеточного и тканевого микроокружения, основанный на идеях и элементах, заимствованных у природы, является современным направлением в развитии медицинского материаловедения и тканевой инженерии. Скеффолд-технологии – многообещающий экспериментальный подход к моделированию свойств природного микроокружения для стволовых клеток. Цель – краткий обзор ключевых элементов микротерриторий ММСК, его перспективных исследований и попыток моделирования в приложении к тканевой инженерии и регенеративной медицине.

EFFECTS OF γс-CYTOKINES (IL-2, IL-7 AND IL-15) UPON IN VITRO MATURATION AND DIFFERENTIATION OF CD4⁺CD45RО⁺/CD8⁺CD45RО⁺ T CELLS

Effect of γс-cytokines (IL-2, IL-7 и IL-15) upon maturation and differentiation of cytotoxic and helper CD45RО+ Tcell population was studied in the homeostatic in vitro culture conditions. We have found that IL-2, IL-7 and IL-15 mediate maturation and differentiation of CD8 T cells central memory, replenishing the population of cells that exhibit effector functions. Action of IL-2 on CD4+ central memory T cells is accociated with generation of effector memory cells by reducing the number of immature effectors (CD62L–CD27+), whereas IL-7 promotes the formation of immature (CD62L–CD27+) effectors. IL-2, IL-7 and IL-15 initiate formation of terminally-differentiated cells in a subpopulation of CD8+CD45RO+ lymphocytes, providing a stable immunological memory to a pathogen reinfestation

Cellular reactions of CD3+ CD4+ CD45RO+ T-lymphocytes on dexamethason in in normal patients and in patients with with rheumatoid arthritis in vitro

The aim of the study was to analyze the influence of glucocorticoid (GC) dexamethasone (Dex) on changes in CD4+ T-cells expressing the surface molecule of activation (CD25, CD71, HLA-DR and CD95) and their ability to produce proinflammatory mediators in cultures of TCR-stimulated CD3+CD45RO+ T-lymphocytes obtained from healthy donors and patients with rheumatoid arthritis in vitro.Materials and methods. The study included 50 patients and 20 healthy donors. T-cell cultures (CD3+ CD45RO+) were obtained from mononuclear leukocytes of immunomagnetic separation (MACS® technology). As an activator of T-lymphocytes, antibiotic particles with biotinylated antibodies against CD2+, CD3+, CD28+, which simulate the process of costimulation of T cells by antigen-presenting cells, were used. The following concentrations of dexamethasone (2, 8, 16, 32, 64 mg) were used in the experiment. The change in the immunophenotype of T-lymphocytes was analyzed by flow cytofluoometry. The secretion of CD3+CD45RO+ T-cells of proinflammatory cytokines IL-2, IFNγ, TNFα, IL-17 and IL-21 was evaluated by enzyme-linked immunosorbent assay.Results. The general suppressor effect of Dex on CD3+CD45RO+ T-cell cultures mediated by a decrease in the number of CD4 + T cells expressing activation molecules (CD25) and proliferation (CD71), as well as inhibition of the production of inflammatory mediators: IFNγ, IL-2 and TNFα. It is shown that against the background of TCR activation Dex increases the number of CD4+CD95+HLA-DR+ cells in CD3+CD45RO+ cultures obtained from RA patients and does not change their content in the control. The correlations between the number of proinflammatory factors (IL-17, IL-21 and TNFα) in CD4+CD45RO+CD95+HLA-DR+ T cells in supernatants of cell cultures in RA patients indicate the presence of a pro-inflammatory potential of this population of T cells. We assume that the resistance of CD4+CD45RO+CD95+HLA-DR+ T cells in RA patients to the suppressor effect of GC generally leads to the preservation and enhancement of the functionality of autoreactive cells in the pathogenesis of RA