The effect of TLR3 priming conditions on MSC immunosuppressive properties

BACKGROUND

Mesenchymal stromal cells (MSCs) have regenerative and immunomodulatory properties, making them suitable for cell therapy. Toll-like receptors (TLRs) in MSCs respond to viral load by secreting immunosuppressive or proinflammatory molecules. The expression of anti-inflammatory molecules in MSCs can be altered by the concentration and duration of exposure to the TLR3 ligand polyinosinic-polycytidylic acid (poly(I:C)). This study aimed to optimize the preconditioning of MSCs with poly(I:C) to increase immunosuppressive effects and to identify MSCs with activated TLR3 (prMSCs).

METHODS

Flow cytometry and histochemical staining were used to analyze MSCs for immunophenotype and differentiation potential. MSCs were exposed to poly(I:C) at 1 and 10 μg/mL for 1, 3, and 24 h, followed by determination of the expression of IDO1, WARS1, PD-L1, TSG-6, and PTGES2 and PGE2 secretion. MSCs and prMSCs were cocultured with intact (J-) and activated (J+) Jurkat T cells. The proportion of proliferating and apoptotic J+ and J- cells, IL-10 secretion, and IL-2 production after cocultivation with MSCs and prMSCs were measured. Liquid chromatography-mass spectrometry and bioinformatics analysis identified proteins linked to TLR3 activation in MSCs.

RESULTS

Poly(I:C) at 10 μg/mL during a 3-h incubation caused the highest expression of immunosuppression markers in MSCs. Activation of prMSCs caused a 18% decrease in proliferation and a one-third increase in apoptotic J+ cells compared to intact MSCs. Cocultures of prMSCs and Jurkat cells had increased IL-10 and decreased IL-2 in the conditioned medium. A proteomic study of MSCs and prMSCs identified 53 proteins with altered expression. Filtering the dataset with Gene Ontology and Reactome Pathway revealed that poly(I:C)-induced proteins activate the antiviral response. Protein‒protein interactions by String in prMSCs revealed that the antiviral response and IFN I signaling circuits were more active than in native MSCs. prMSCs expressed more cell adhesion proteins (ICAM-I and Galectin-3), PARP14, PSMB8, USP18, and GBP4, which may explain their anti-inflammatory effects on Jurkat cells.

CONCLUSIONS

TLR3 activation in MSCs is dependent on exposure time and poly(I:C) concentration. The maximum expression of immunosuppressive molecules was observed with 10 µg/mL poly(I:C) for 3-h preconditioning. This priming protocol for MSCs enhances the immunosuppressive effects of prMSCs on T cells.

Biochemical markers of connective tissue metabolism in the diagnostics of respiratory diseases in human and animals: retrospective analysis (1984–2010)

The aim: to analyze the literature data for the period from 1984 to 2010 on the use of biochemical markers of disorders of connective tissue metabolism in diseases of the respiratory system in humans and animals. Materials and methods. The research was conducted by the method of scientific literature open source analysis: PubMed, Elsevier, electronic resources of the National Library named after V.I. Vernadsky (1984–2010). Results. In the case of diseases of the respiratory system in humans, the pathogenesis of pneumonia is the development of inflammation in the interstitial, peribronchial, perivascular and perilobular connective tissue, lymphatic vessels of the lungs, followed by involvement of alveoli and bronchioles in the inflammation. The morphological basis of these changes may be pneumofibrosis and pneumosclerotic changes. In the chronic course of pneumonia, chronic obstructive pulmonary disease develops. This pathology is closely related to the action of inflammatory cytokines that regulate connective tissue proliferation. Similar studies were performed on eosinophilic bronchopneumonia in dogs, but the material for the study was bronchoalveolar lavage. The current method of diagnosing respiratory diseases using cytokines (interleukin-4, interferon-γ) and bronchoalveolar lavage has no diagnostic information in chronic bronchitis and bronchial asthma in cats. Fundamental studies of connective tissue biopolymers in clinically healthy and bronchopneumonia piglets have recently been conducted in veterinary medicine. Conclusions. Recently, in medicine of particular interest to researchers is the determination of the content in biological fluids of indicators of connective tissue metabolism (hydroxyproline, glycosaminoglycans, glycoproteins, sialic acids) to diagnose diseases of the respiratory system. To diagnose connective tissue disorders in lung diseases in medical practice use indicators of oxyproline in serum and urine. Oxyproline is one of the most important components of lung collagen. An increase in the content of free oxyproline in the blood indicates an increased rate of collagen breakdown in the lung tissue. Analysis of oxyproline fractions, as indicators of the direction of collagen metabolism, allows to assess the condition of the connective tissue of the lungs and can serve as a prognostic criterion for the course of the disease. Thus, the indicators of connective tissue metabolism showed significant diagnostic information, which allowed to recommend them for use in the practice of veterinary medicine.

Pathogenesis and methods of diagnosis of chronic kidney disease in cats: retrospective analysis (1981–2007)

The aim: to conduct a retrospective analysis of literature sources on the pathogenesis and methods of diagnosis of chronic kidney disease in cats. Materials and methods. The research was conducted by the method of scientific literature open-source analysis: PubMed, Elsevier, electronic resources of the National Library named after V.I. Vernadsky (1981–2007). Results. Chronic kidney disease is a common reason for cat owners to go to veterinary clinics. The term “chronic kidney disease” has a broader meaning than the more limited and not very specific name – chronic renal failure; it is also used to indicate the preazotemic stage of the disease. Chronic kidney disease is characterized by a gradual deterioration of the clinical condition of animals due to progressive decline in renal function. An idea of the pathogenesis and methods of diagnosis of chronic kidney disease in the period from 1981 to 2007 is presented. Conclusions. According to the results of retrospective analysis of literature sources for the period from 1981 to 2007, the basis was identified aspects of the pathogenesis of chronic kidney disease in domestic cats, which have not lost relevance today. The main link during chronic kidney disease in cats is the development of hyperazotemia and, as a consequence, endogenous intoxication of the body, which develops gradually and leads to the death of the animal. The morphological basis of chronic kidney disease in cats is the development of diffuse nephrosclerosis, which is reflected in the results of clinical, biochemical and instrumental studies. According to biochemical analysis of blood, in cats recorded an increase in urea and creatinine, the results of clinical studies of urine showed a decrease in its relative density, as well as the development of proteinuria, the appearance of erythrocytes and cylinders. According to the results of hematological research, anemic syndrome develops due to decreased erythropoietin synthesis. With age in cats, ultrasound examination of the kidneys reveals a decrease in their volume due to uniform sclerosis of the parenchyma: it is determined by its thinning and increased echogenicity due to the accumulation of connective tissue components, which is a sign of nephrosclerosis. Although kidney biopsy is the most informative method of diagnosing chronic kidney disease, it has many contraindications, which does not allow its use in the routine diagnosis of nephropathy in domestic cats. its thinning and increase in echogenicity due to the accumulation of connective tissue components, which is a sign of nephrosclerosis, is determined. Although kidney biopsy is the most informative method of diagnosing chronic kidney disease, it has many contraindications, which does not allow its use in the routine diagnosis of nephropathy in domestic cats. Its thinning and increase in echogenicity due to the accumulation of connective tissue components, which is a sign of nephrosclerosis, is determined

Dose-dependent effect of chronic exposure to lead acetate on the dynamics of the content of delta-aminolevulinic acid and essential trace elements in the serum of laying hens

  One of the most global and dangerous pollutants is considered to be lead, due to its ability to accumulate in living organisms, to be included in the metabolic cycle, to form highly toxic organometallic compounds, not being biodegradable. To study the chronic effects of lead acetate, an experiment was performed on laying hens of Lohmann Brown cross. For research, one control and three experimental groups were formed, 20 chickens in each. Birds of the experimental groups were administered lead acetate daily with compound feed in doses (in terms of metal): Group I – 50 mg/kg of feed, II – 75 mg/kg of feed, III – 150 mg/kg of feed. Access to water was not restricted. The birds of the control group received a complete diet without lead acetate. On the 30th, 90th, 120th days of the experiment and the 20th day after withdrawal of the toxicant (the 140th day of the experiment), we took blood samples from birds for biochemical and toxicological studies. The concentration of delta-aminolevulinic acid (δ-ALA) in the serum of laying hens was determined by reversed-phase high-performance liquid chromatography. Determination of the content of lead in the serum of laying hens was performed by X-ray fluorescence analysis. The concentration of total calcium, inorganic phosphorus, and magnesium in the serum of the laying hens was determined using production kits. We detected the dose-dependent chronic effect of lead acetate on the dynamics of the content of delta-aminolevulinic acid and essential trace elements in the serum of laying hens. The administration of lead acetate into the body of productive poultry for 120 days in doses of 50, 75, and 150 mg/kg with feed did not cause visible clinical signs of poisoning, but caused a violation of porphyrin metabolism, manifested in a reliable increase in the concentration of delta-aminolevulinic acid in serum on the 30th, 90th and 120th days of the experiment. It has been experimentally proven that the administration into the body of laying hens of lead acetate in doses of 50, 75 and 150 mg/kg of feed for 120 days leads to the maximum accumulation of lead in the serum on the 30th, 90th, and 120th days of the experiment. Prolonged administration of lead acetate to laying hens at high concentrations is characterized by a reliable decrease in the content of total calcium, inorganic phosphorus and magnesium in the serum of laying hens and a reliable increase in the content of ferrum. In the future it is necessary to study the intensity of lipid peroxidation processes in laying hens under chronic exposure to lead acetate.

The effect of a formulation based on maduramycin and nicarbazine on rats and broiler chickens in a subacute experiment

The aim: to determine the effect of a preparative form of an antiemeric agent based on maduramycin and nicarbazine on the body of white rats and broiler chickens under the conditions of a subacute experiment. Materials and methods. The formulation based on maduramycin and nicarbazine was administered to rats and broiler chickens with feed for 28 days. One control and three experimental groups were formed for the experiment: Group I – animals received a complete diet without admixture of the formulation (control group), Group II – animals that were administered the formulation (by the amount of active substances) at a dose of 5.0 mg / kg, III – 25.0 mg / kg and IV – 50.0 mg / kg of feed, respectively. In order to establish the toxic effect of the formulation on the body of experimental birds on 7, 14, 28 days of the experiment and 7 days after discontinuation of the formulation, 5 heads from each group were killed under light ether anesthesia, blood samples were taken for hematological and biochemical studies. Results. During the study of the general clinical condition of rats and broiler chickens of the experimental groups, no significant changes in behavior and appearance were detected, compared with the control. Hematological parameters of broiler chickens it was found that the receipt of the formulation with feed at doses of 5, 25 and 50 mg/kg body weight, causes a decrease in hemoglobin and an increase in hematocrit in broiler chickens on day 7 of the experiment. It was found that the changes are reversible, on the 28th day of the experiment the value of these indicators was within the physiological norm. In the study of hematological and biochemical parameters of rats, it was found that the receipt of the formulation with food in doses of 25.0 and 50.0 mg/kg for 28 days, causes a decrease in hemoglobin and increase hematocrit, total protein, albumin, creatinine and urea in male rats on the 7th day of the experiment. Conclusions. Under conditions of repeated oral administration of the preparation mixture to rats and poultry at doses of 5, 25 and 50 mg/kg body weight in the absence of clinical signs of poisoning, insignificant fluctuations in hematological and biochemical parameters were identified

Pseudomonas aeruginosa as a priority group representative of bacteria with multiple antibiotic resistance

The aim: the aim of the research is an analytical review of the scientific literature on Рseudomonas aeruginosa as a priority group representative of bacteria with multiple antibiotics resistance. Materials and methods. The research was conducted by the method of scientific literature open source analysis: PubMed, Elsevier, electronic resources of the National Library named after V. I. Vernadsky and others. Results. The problem of antibiotic resistance is rightly called the “apocalypse of the XXI century”. P. aeruginosa bacteria are characterized by a very high natural ability to form resistant forms to antimicrobial drugs due to the formation of specific resistance genes, the ability to resist the entry of antibiotics into the cell or remove antibiotics from the cell, and form biofilms. A characteristic feature of the epidemic and epizootic processes of P. aeruginosa, as an opportunistic ubiquitous microorganism is host-pathogenic interaction - the interaction of the pathogen with the host organism. The peculiarity of this bacterium is opportunism and long-term persistence in the body of the host and in the environment. The global trend towards the spread of antibiotic-resistant gram-negative bacteria, including P. aeruginosa, underscores the need to develop comprehensive response strategies targeting all sectors of health. Conclusions. Bacteria P. aeruginosa is classified in 1th Critical Group of the WHO list of resistant to antibiotics "priority pathogens". Among the main reasons that contribute to the emergence of resistance are irrational antibiotic therapy in both humans and animals, and the use of antibiotics as growth stimulants in animal husbandry. While more R&D is vital, alone, it cannot solve the problem. To address resistance, there must also be better prevention of infections and appropriate use of existing antibiotics in humans and animals, as well as rational use of any new antibiotics that are developed in future. New methods of combating antibiotic resistance and antibacterial substances, alternatives to antibiotics (biofilm-destroying drugs, antimicrobial peptides (AMP), bacteriophages, nanopreparations, etc.) can make a positive contribution to overcoming the multiple drug resistance of gram-negatives

Determination of toxicological characteristics of a complex antiemeric drug based on maduramycin and nicarbazine

The aim: to determine the parameters of acute toxicity of the preparative form of an antiemeric agent based on maduramycin and nicarbazine for white mice, white rats and guinea pigs with a single oral administration. Materials and methods. Determination of acute toxicity of the formulation by oral administration was performed on 48 adult male mice, 48 adult nonlinear male rats, 48 adult male guinea pigs. To conduct an experiment on the principle analogues were formed seven experimental and one control group, 6 animal each. The dose of the formulation was calculated individually based on body weight values. It should be noted that the total volume of the emulsion of the formulation administered orally is not exceeded 1.0 cm3per 100 gram b. w. Results. Toxicometric parameters of the formulation were calculated by the method of least squares for probit analysis of mortality curves. It was found that the LD50 of the preparative form of antiemeric agent for white mice for a single oral administration is 238.05±28.08 mg/kg, LD16 – 128.71 mg/kg, LD84 – 347.39 mg/kg, LD100 - 402, 06 mg/kg body weight, respectively. LD50 of the preparative form of antiemeric agent for white rats with a single oral administration is 260.51±28.83 mg/kg, LD16 – 148.39 mg/kg, LD84 – 372.65 mg/kg, LD100 – 428.71 mg/kg body weight, respectively. LD50 of the preparative form of antiemeric agent for guinea pigs for a single oral administration is 275±21.12 mg/kg, LD16 – 201.74 mg/kg, LD84 – 348.25 mg/kg, LD100 – 384.88 mg/kg body weight body respectively. Conclusions. According to SOU 85.2-37-736: 2011 "Veterinary drugs. Determination of acute toxicity” preparative form of a complex antiemeric agent based on maduramycin and nicarbazine on the degree of toxicity can be attributed to moderately dangerous substances (3rd hazard class)