Репозиторий Университета

© 2021, The Author(s). Background: The acute phase response (APR) to CNS insults contributes to the overall magnitude and nature of the systemic inflammatory response. Aspects of this response are thought to drive secondary inflammatory pathology at the lesion site, and suppression of the APR can therefore afford some neuroprotection. In this study, we examined the APR in a mouse model of traumatic spinal cord injury (SCI), along with its relationship to neutrophil recruitment during the immediate aftermath of the insult. We specifically investigated the effect of IL-1 receptor antagonist (IL-1RA) administration on the APR and leukocyte recruitment to the injured spinal cord. Methods: Adult female C57BL/6 mice underwent either a 70kD contusive SCI, or sham surgery, and tissue was collected at 2, 6, 12, and 24 hours post-operation. For IL-1RA experiments, SCI mice received two intraperitoneal injections of human IL-1RA (100mg/kg), or saline as control, immediately following, and 5 hours after impact, and animals were sacrificed 6 hours later. Blood, spleen, liver and spinal cord were collected to study markers of central and peripheral inflammation by flow cytometry, immunohistochemistry and qPCR. Results were analysed by two-way ANOVA or student’s t-test, as appropriate. Results: SCI induced a robust APR, hallmarked by elevated hepatic expression of pro-inflammatory marker genes and a significantly increased neutrophil presence in the blood, liver and spleen of these animals, as early as 2 hours after injury. This peripheral response preceded significant neutrophil infiltration of the spinal cord, which peaked 24 hours post-SCI. Although expression of IL-1RA was also induced in the liver following SCI, its response was delayed compared to IL-1β. Exogenous administration of IL-1RA during this putative therapeutic window was able to suppress the hepatic APR, as evidenced by a reduction in CXCL1 and SAA-2 expression as well as a significant decrease in neutrophil infiltration in both the liver and the injured spinal cord itself. Conclusions: Our data indicate that peripheral administration of IL-1RA can attenuate the APR which in turn reduces immune cell infiltration at the spinal cord lesion site. We propose IL-1RA treatment as a viable therapeutic strategy to minimise the harmful effects of SCI-induced inflammation.

© 2020 Elsevier B.V. Neutrophils release neutrophil extracellular traps (NETs) in response to numerous pathogenic microbes as the last suicidal resource (NETosis) in the fight against infection. Apart from the host defense function, NETs play an essential role in the pathogenesis of various autoimmune and inflammatory diseases. Therefore, understanding the molecular mechanisms of NETosis is important for regulating aberrant NET release. The initiation of NETosis after the recognition of pathogens by specific receptors is mediated by an increase in intracellular Ca2+ concentration, therefore, the use of Ca2+ ionophore A23187 can be considered a semi-physiological model of NETosis. Induction of NETosis by various stimuli depends on reactive oxygen species (ROS) produced by NADPH oxidase, however, NETosis induced by Ca2+ ionophores was suggested to be mediated by ROS produced in mitochondria (mtROS). Using the mitochondria-targeted antioxidant SkQ1 and specific inhibitors of NADPH oxidase, we showed that both sources of ROS, mitochondria and NADPH oxidase, are involved in NETosis induced by A23187 in human neutrophils. In support of the critical role of mtROS, SkQ1-sensitive NETosis was demonstrated to be induced by A23187 in neutrophils from patients with chronic granulomatous disease (CGD). We assume that Ca2+-triggered mtROS production contributes to NETosis either directly (CGD neutrophils) or by stimulating NADPH oxidase. The opening of the mitochondrial permeability transition pore (mPTP) in neutrophils treated by A23187 was revealed using the electron transmission microscopy as a swelling of the mitochondrial matrix. Using specific inhibitors, we demonstrated that the mPTP is involved in mtROS production, NETosis, and the oxidative burst induced by A23187.

© 2019, © 2019 Informa UK Limited, trading as Taylor  &  Francis Group. Human polymorphonuclear leukocytes (PMNLs, neutrophils) play a major role in the immune response to bacterial and fungal infections and eliminate pathogens through phagocytosis. During phagocytosis of microorganisms, the 5-lipoxygenase (5-LOX) pathway is activated resulting in generation of leukotrienes, which mediate host defense. In this study, a library of oligodeoxyribonucleotides (ODNs) with varying numbers of human telomeric repeats (d(TTAGGG)n) and their analogues with phosphorothioate internucleotide linkages and single-nucleotide substitutions was designed. These ODNs with the potential to fold into G-quadruplex structures were studied from structural and functional perspectives. We showed that exogenous G-quadruplex-forming ODNs significantly enhanced 5-LOX metabolite formation in human neutrophils exposed to Salmonella Typhimurium bacteria. However, the activation of leukotriene synthesis was completely lost when G-quadruplex formation was prevented by substitution of guanosine with 7-deazaguanosine or adenosine residues at several positions. To our knowledge, this study is the first to demonstrate that G-quadruplex structures are potent regulators of 5-LOX product synthesis in human neutrophils in the presence of targets of phagocytosis. Communicated by Ramaswamy H. Sarma.

© 2019 The Journal of Rheumatology. All rights reserved. Objective. To determine whether neutropenia is associated with increased risk for infection in patients with systemic juvenile idiopathic arthritis (sJIA) and polyarticular-course juvenile idiopathic arthritis (pcJIA) treated with tocilizumab (TCZ). Methods. Data up to Week 104 from 2 phase III trials of intravenous TCZ in sJIA (n = 112; ClinicalTrials.gov, NCT00642460) and pcJIA (n = 188; ClinicalTrials.gov, NCT00988221) were pooled. Worst common toxicity criteria grade and lowest observed absolute neutrophil count (ANC) were identified for each patient. Associations between patient characteristics and lowest observed ANC were tested using univariate regression analysis. Infection and serious infection rates per 100 patient-years (PY) in periods associated with grades 1/2 and 3/4 neutrophil counts were compared with rates associated with normal neutrophil counts. Results.ANC decreased to grade ≥ 3 in 25.0% and 5.9% of sJIA and pcJIA patients, respectively, and decreases were transient. Young age (p = 0.047) and methotrexate use (p = 0.012) were positively associated with neutropenia in patients with sJIA but not in patients with pcJIA. The rate of serious infections in patients with sJIA (10.9/100 PY; 95% CI 6.8-16.5) tended to be higher than in patients with pcJIA (5.2/100 PY; 95% CI 3-8.5). No increase in rates of serious or nonserious infections was observed during periods of neutropenia in either trial. Conclusion. Patients with JIA treated with TCZ experienced transient neutropenia that was not associated with an increased number of infections.

© 2018 Vitebsk State Medical University. All rights reserved. Objective: To study the functional activity and cytoarchitectonics of neutrophilic granulocytes by the atomic force microscopy technique in the patients with mechanical jaundice of benign genesis of varying severity. Methods: The subject of the study were 92 patients aged from 47 to 69 years undergoing the in-patient treatment in the surgical departments of medical institutions in Krasnoyarsk with the diagnosis of mechanical jaundice of benign genesis. The control group consisted of 60 donors, comparable in sex and age with the main group. Depending on the severity of mechanical jaundice, luminol-dependent chemiluminescence of neutrophils was investigated and atomic-force microscopy of neurophilic granulocytes was performed to determine the shape, membrane state, geometric dimensions and adhesion forces of the blood neutrophils. Results: In patients with mechanical jaundice, the intensity of spontaneous chemiluminescence depends on the severity of mechanical jaundice. The kinetics of the chemiluminescent response of the peripheral blood neutrophils indicates an increase in the compensatory functional capacity of this cell population in case of mild degree of mechanical jaundice severity with their depletion in parallel with the increase in the severity of mechanical jaundice. Atomic force microscopy revealed violations of the structural organization of the neutrophil granulocyte. With increasing severity of mechanical jaundice, neutrophil became convex in shape, the number of segments of the nucleus increased, the cell membrane became irregular, the neutrophil volume reached 62.20 + 5.94 m3. The magnitude of the adhesion forces of neutrophils decreased by 25% in patients with class B severity of mechanical jaundice and by 31% with class C severity of mechanical jaundice. Conclusions: Based on the analysis of the chemiluminescent activity of neutrophilic granulocytes and their cytoarchitectonics, we concluded that the functional capabilities of neutrophilic granulocytes in mechanical jaundice are depleted in parallel with the increase in the severity of mechanical jaundice. Dysfunctions of neutrophils in mechanical jaundice are caused by the change in its cytoarchitectonics and by the decrease in adhesion forces.

© 2018, Bionika Media Ltd.. All rights reserved. Objective. To investigate the relationship of the levels of preactivated (primed) neutrophils in the peripheral blood of pregnant women with preeclampsia. Subjects and methods. The investigation enrolled 14 women with preeclampsia (a study group, Group 1), 15 women with physiological pregnancy (a control group, Group 2), and 11 non-pregnant women (to obtain normative values). Formyl peptide, Ficoll-Hypaque (1.077 and 1.119 g/ml) gradients, lucigenin, Roswell Park Memorial Institute (RPMI) 1640 medium, Hanks medium, and fetal calf serum (Sigma-Aldrich) were determined in the peripheral blood. Neutrophils were isolated from the blood samples obtained from the ulnar vein (the anticoagulant heparin 35 IU/ml) using a two-step Ficoll-Hypaque gradient. Red blood cells were destroyed by hypotonic lysis. Neutrophils in the suspensions were at least 96%. The live cells tested with trypan blue were 94%. Suspensions containing 1×106 сells/ml were prepared. Formyl-methionyl-leucyl-phenylalanine (fMLP, 2 µM) was used as a stimulant. The formation of oxygen radicals was recorded in imp/sec, by using the luminophor lucigenin (30 µM) on a Biotox-7 chemiluminometer (Russia). The maximum radical formation amplitude, the time of its achievement, and the light sum were determined for a fixed time period. Results. The cell suspensions from non-pregnant women showed a monotonic spontaneous increase in oxygen radical formation at a very low rate. The rate increased by 1.3 times in healthy pregnant women (p > 0.05). The rate of spontaneous oxygen radical generation rose sharply in pregnant women with preeclampsia. In this group, the formation of oxygen radicals reached maximum values and plateaued at 24±7 min. The spontaneous radical formation might be due to the stimulation of initially primed neutrophils as a result of their adhesion on the cell walls. To test this assumption, the standard stimulant fMLP that strongly stimulates the neutrophil generation of oxygen radicals were added to the suspensions from the women with preeclampsia. It should be noted that in both non-pregnant women and healthy pregnant women, fMLP significantly increased the level of radicals compared to the responses of neutrophils in women with preeclampsia. Conclusion. The potentiated response to formyl peptide due to spontaneous neutrophil stimulation in pregnant women with preeclampsia suggests that their peripheral blood contain primed cells. This total response may suggest that the mechanism of stimulation of neutrophils due to their adhesion on the cell wall and to fMLP stimulation is different, additive in nature, and is carried out by different processes.

© 2018, SPb RAACI.  Modern studies have shown a high plasticity and phenotypic diversity of neutrophilic granulocytes (NG) provided by different receptors, which are diagnostic markers for the functional capacity of the cell in the course of their activities. We investigated NG from peripheral blood, obtained from healthy people of both sexes aged from 26 to 66 years. Evaluation of the neutrophil membrane receptor expression was carried out by flow cytometry. The relative amount of neutrophilic granulocytes expressing membrane CD62L, CD63, CD66d receptors and the intensity of their expression were determined according to their fluorescence intensities. The surface NG membrane receptors, i.e., CD62L, CD63, CD66d were studied upon the in vitro experimental influence of the following bacterial peptides: N-formyl-methionyl-leucyl-phenylalanine (FMLP, model 1); glucosaminylmuramyldipeptide (GMDP, model 2), and simultaneous incubation of NG blood with fMLP and GMDP (model 3). The in vitro treatment with fMLP in the in vitro model was used to transform the NG phenotype of conventionally healthy subjects, expressing CD62, CD63, CD66d molecules. The treatment caused a significantly decrease in both CD62L and the CD62L expression in relative amounts of neutrophilic granulocytes with a parallel increase of CD63 expression density. The effect of GMDP on the NG phenotype of conditionally healthy subjects did not change the amount of CD62L + NG and CD63 + NG, and did not affect CD62L and CD63 expression density on the surface of NG. However, the amount of CD66d + NG was significantly increased with the unchanged expression of CD66d molecules. GMDP introduced together with the bacterial fMLP peptide was shown to neutralize some features of the NG phenotype transformation caused by fMLP, i.e., the amount of CD62L + NG was restored by 22 % and the CD62L expression density increased significantly. At the same time, GMDP did not correct the negative effect of fMLP upon the number of CD63 + NG and CD66d + NG, and on the CD63 and CD66d expression. Simultaneous addition of fMLP and GMDP did significantly increase the amount of CD66d + NG and expression density of CD63 molecules on the CD63 + NG membrane as compared to intact NG of conditionally healthy subjects. The obtained data are important in order to justify some new immunotherapeutic strategies aimed at correction of the negatively transformed NG phenotype, which accompanies some infectious and inflammatory diseases of bacterial etiology with atypical clinical course.