Сапожников Александр Михайлович

Избранные публикации

  1. Boyko A.A., Azhikina T.L., Streltsova M.A., Sapozhnikov A.M., Kovalenko E.I. (2016). HSP70 in human polymorphonuclear and mononuclear leukocytes: comparison of the protein content and transcriptional activity of HSPA genes. Cell Stress Chaperones , [+]

    Cell-type specific variations are typical for the expression of different members of the HSP70 family. In circulating immune cells, HSP70 proteins interact with units of signaling pathways involved in the immune responses and may promote cell survival in sites of inflammation. In this work, we compared basal HSP70 expression and stress-induced HSP70 response in polymorphonuclear and mononuclear human leukocytes. The intracellular content of inducible and constitutive forms of HSP70 was analyzed in relation to the transcriptional activity of HSPA genes. Hyperthermia was used as the stress model for induction of HSP70 synthesis in the cells. Our results demonstrated that granulocytes (mainly neutrophils) and mononuclear cells differ significantly by both basal HSP70 expression and levels of HSP70 induction under hyperthermia. The differences were observed at the levels of HSPA gene transcription and intracellular HSP70 content. The expression of constitutive Hsс70 protein was much higher in mononuclear cells consisting of monocytes and lymphocytes than in granulocytes. At the same time, intact neutrophils showed increased expression of inducible Hsp70 protein compared to mononuclear cells. Heat treatment induced additional expression of HSPA genes in leukocytes. The most pronounced increase in the expression was observed in polymorphonuclear and mononuclear leukocytes for HSPA1A/B. However, in granulocytes, the induction of the transcription of the HSPA8 gene encoding the Hsc70 protein was significantly higher than in mononuclear cells. These variations in transcriptional activity of HSPA genes and intracellular HSP70 content in different populations of leukocytes may reflect specified requirements for the chaperone activity in the cells with a distinct functional role in the immune system.

    ID:1663
  2. Shevchenko M.A., Troyanova N.I., Servuli E.A., Bolkhovitina E.L., Fedorina A.S., Sapozhnikov A.M. (2016). Study of immunomodulatory effects of extracellular HSP70 in a mouse model of allergic airway inflammation. BIOCHEMISTRY(Moscow) 81 (11), 1384–1395 ID:1659
  3. Troyanova N.I., Shevchenko M.A., Boyko A.A., Mirzoyev R.R., Pertseva M.A., Kovalenko E.I., Sapozhnikov A.M. (2015). Modulating Effect of Extracellular HSP70 on Generation of Reactive Oxigen Species in Populations of Phagocytes. Russ. J. Bioorgan. Chem. 41 (3), 271–279 [+]

    Reactive oxygen species (ROS) produced by phagocytic cells of the innate immune system play an important role in the first line of defense protecting the host from pathogens. The NADPH oxidase multi-subunit complex is the main source of ROS in all types of the phagocytes. Formation of the membrane-associated enzyme complex and its activity are dependent on many different factors controlling both intensification and suppression of the ROS production rate. However, the evidences are emerging in recent years indicating existence of poorly studied mechanisms of restriction of ROS generation level in phagocytes directed at protection of host tissues in the sites of inflammation from destruction caused by the oxygen free radicals. Our previous data and results of other authors demonstrate that a mechanism of the limitation of ROS production by phagocytes may by connected with immunomodulating activity of extracellular pool. of HSP70. In the present work, we used inhibitors of NADPH oxidase and in vitro cultures of different phagocytes to study a possible relationship between down-regulating effect of exogenous HSP70 on ROS generation and the interaction of the protein with the enzyme subunits. Our results confirmed the literature data concerning the ability of extracellular HSP70 to modulate NADPH oxidase activity and demonstrated for the first time an inhibitory effect of the protein on intracellular ROS generation in phagocytes.

    ID:1502
  4. Israel L.L., Kovalenko E.I., Boyko A.A., Sapozhnikov A.M., Rosenberger I., Kreuter J., Passoni L., Lellouche J.P. (2015). Towards hybrid biocompatible magnetic rHuman serum albumin-based nanoparticles: use of ultra-small (CeLn)3/4+ cation-doped maghemite nanoparticles as functional shell. Nanotechnology 26 (4), ID:1152
  5. Semenkov V.F., Michalski A.I., Sapozhnikov A.M. (2015). Heating and ultraviolet light activate anti-stress gene functions in humans. Front Genet 6, 245 [+]

    Different environmental factors (i.e., toxins, heavy metals, ultraviolet (UV) rays, and X-radiation) cause damage to DNA, cell membranes and other organelles and induce oxidative stress, which results in the excessive production of reactive oxygen species (ROS) by phagocytes. All types of cell stress are accompanied by the activation of anti-stress genes that can suppress ROS synthesis. We hypothesized that different environmental factors would affect organisms through the activation of anti-stress genes by autologous serum (AS) proteins, followed by the synthesis of molecules that increase cell resistance to oxidative stress. The goal of this work was to study the influence of AS on ROS production by peripheral blood neutrophils isolated from donors in different age groups. Neutrophils were isolated from 59 donors (38-94 years old). AS was heated at 100°C for 30 s. or irradiated by UV light at 200-280 nm and 8 W for 10 min. Neutrophils were exposed to heat shock at 42°C for 1 min. (short-term heating stress) or 43°C for 10 min., followed by the determination of the chemiluminescence reaction induced by zymosan. AS can increase or decrease ROS production by neutrophils depending on the structure of the proteins in the serum; these structures can be changed by heating or UV treatment and the temperature of their interaction (4 or 37°C). We propose that the effect of environmental factors on AS proteins can cause an adverse increase in oxidative stress levels due to the functional reduction of anti-stress genes. We found a negative correlation between the quantity of intracellular Hsp70 and levels of intracellular ROS production following 10 min of heat shock at 43°C. Short-term heating stress (1 min) at 42°C was followed by a prominent reduction in ROS production. This effect may be a result of the impact of the hormone adrenaline on the functions of anti-stress genes. Indeed, the same effect was observed after treatment of the neutrophils with adrenaline at concentrations of 10(-4) and 10(-5) M. In contrast, dexamethasone from the other stress hormone group did not evoke the same effect at the same concentrations.

    ID:1500
  6. Kovalenko E.I., Boyko A.A., Semenkov V.F., Lutsenko G.V., Grechikhina M.V., Kanevskiy L.M., Azhikina T.L., Telford W.G., Sapozhnikov A.M. (2014). ROS production, intracellular HSP70 levels and their relationship in human neutrophils: effects of age. Oncotarget 5 (23), 11800–12 [+]

    ROS production and intracellular HSP70 levels were measured in human neutrophils for three age groups: young (20-59 years), elders (60-89 years) and nonagenarians (90 years and older). Elders showed higher levels of spontaneous intracellular ROS content compared with young and nonagenarian groups, which had similar intracellular ROS levels. Zymosan-induced (non-spontaneous) extracellular ROS levels were also similar for young and nonagenarians but were lower in elders. However, spontaneous extracellular ROS production increased continuously with age. Correlation analysis revealed positive relationships between HSP70 levels and zymosan-stimulated ROS production in the elder group. This was consistent with a promoting role for HSP70 in ROS-associated neutrophils response to pathogens. No positive correlation between ROS production and intracellular HSP70 levels was found for groups of young people and nonagenarians. In contrast, significant negative correlations of some ROS and HSP70 characteriscics were found for neutrophils from young people and nonagenarians. The observed difference in ROS and HSP70 correlations in elders and nonagenarians might be associated with an increased risk of mortality in older individuals less than 90 years old.

    ID:1140
  7. Kanevskiy L.M., Erokhina S.A., Streltsova M.A., Telford W.G., Sapozhnikov A.M., Kovalenko E.I. (2014). Bacterial lipopolysaccharide activates CD57-negative human NK cells. Biochemistry Mosc. 79 (12), 1339–48 [+]

    NK cells play an important regulatory role in sepsis by induction and augmentation of proinflammatory reactions in early stages of the septic process and by suppression of immune response in later stages of inflammation. The present work was aimed at the effect of bacterial lipopolysaccharide (LPS), the main pathogenic factor of sepsis development, on human NK cells ex vivo. We show that LPS activates immature CD57-negative NK cells, which typically constitute less than half of the normal NK cell population in human peripheral blood. Under conditions of NK cell stimulation with IL-2, addition of LPS provokes an increase in IFN-γ production. However, LPS both increased and inhibited NK cell cytotoxic activity. It is important to note that the activation of NK cells on LPS addition was observed in the absence of TLR4 on the NK cell surface. These results confirm our previous data arguing for a direct interaction of LPS with NK cells and evidence an atypical mechanism of LPS-induced NK cell activation without the involvement of surface TLR4.

    ID:1258
  8. Бойко А.А., Ветчинин С.С., Сапожников А.М., Коваленко Е.И. (2014). Изменение уровня белков теплового шока семейства 70 кДа в нейтрофилах человека под действием теплового шока. Биоорг. хим. 40 (5), 528–540 ID:1156
  9. Shevchenko M.A., Bolkhovitina E.L., Servuli E.A., Sapozhnikov A.M. (2013). Elimination of Aspergillus fumigatus conidia from the airways of mice with allergic airway inflammation. Respir. Res. 14, 78 [+]

    Aspergillus fumigatus conidia can exacerbate asthma symptoms. Phagocytosis of conidia is a principal component of the host antifungal defense. We investigated whether allergic airway inflammation (AAI) affects the ability of phagocytic cells in the airways to internalize the resting fungal spores.

    ID:987
  10. Kanevskiy L.M., Telford W.G., Sapozhnikov A.M., Kovalenko E.I. (2013). Lipopolysaccharide induces IFN-γ production in human NK cells. Front Immunol 4, 11 [+]

    Natural killer (NK) cells have been shown to play a regulatory role in sepsis. According to the current view, NK cells become activated via macrophages or dendritic cells primed by lipopolysaccharide (LPS). Recently, TLR4 gene expression was detected in human NK cells suggesting the possibility of a direct action of LPS on NK cells. In this study, effects of LPS on NK cell cytokine production and cytotoxicity were studied using highly purified human NK cells. LPS was shown to induce IFN-γ production in the presence of IL-2 in NK cell populations containing>98% CD56(+) cells. Surprisingly, in the same experiments LPS decreased NK cell degranulation. No significant expression of markers related to blood dendritic cells, monocytes or T or B lymphocytes in the NK cell preparations was observed; the portions of HLA-DR(-bright), CD14(+), CD3(+), and CD20(+) cells amounted to less than 0.1% within the cell populations. No more than 0.2% of NK cells were shown to be slightly positive for surface TLR4 in our experimental system, although intracellular staining revealed moderate amounts of TLR4 inside the NK cell population. These cells were negative for surface CD14, the receptor participating in LPS recognition by TLR4. Incubation of NK cells with IL-2 or/and LPS did not lead to an increase in TLR4 surface expression. TLR4(-)CD56(+) NK cells isolated by cell sorting secreted IFN-γ in response to LPS. Antibody to TLR4 did not block the LPS-induced increase in IFN-γ production. We have also shown that R(e)-form of LPS lacking outer core oligosaccharide and O-antigen induces less cytokine production in NK cells than full-length LPS. We speculate that the polysaccharide fragments of LPS molecule may take part in LPS-induced IFN-γ production by NK cells. Collectively our data suggest the existence of a mechanism of LPS direct action on NK cells distinct from established TLR4-mediated signaling.

    ID:1158
  11. Луценко Г.В., Гречихина М.В., Дьячкова Л.Г., Сапожников А.М. (2013). Протективное действие аутокринных факторов цитотоксических Т-лимфоцитов в условиях химической гипоксии. Иммунология 34 (5), 251–254 ID:1166
  12. Shevchenko M.A., Bolkhovitina E.L., Servuli E.A., Sapozhnikov A.M. (2013). Elimination of Aspergillus fumigatus conidia from the airways of mice with allergic airway inflammation. Respir. Res. , ID:1241
  13. Kovalenko E., Kanevskiy L., Klinkova A., Kuchukova A., Streltsova M., Telford W., Sapozhnikov A. (2012). Stress-Induced Molecules in Regulation of NK Cell Activity. Chapter in a book “Cell Interaction” , 93–120 ID:1168