Myeloid-derived suppressor cells (MDSC) emerged as major factors driving the tumor progression due to numerous immunosuppressive mechanisms they possess. Prostaglandin (PG)E2 is shown critical for ...the induction of MDSC and their suppressive functions
, but it is poorly understood how it affects the capacity of MDSC to induce different subsets of regulatory T cells (Treg). By using a novel protocol for the generation of mononuclear (M)-MDSC, we showed that PGE2 potentiates the GM-CSF/IL-6-dependent induction of CD33
CD11b
HLA-DR
CD14
M-MDSC
. PGE2 diminished the capacity of GM-CSF/IL-6 M-MDSC to produce proinflammatory cytokines upon activation and augmented their capacity to produce IL-27, IL-33, and TGF-β. These results correlated with an increased potential of GM-CSF/IL-6/PGE2 M-MDSC to suppress T cell proliferation, expand alloreactive Th2 cells, and reduce the development of alloreactive Th17 and cytotoxic T cells. Interestingly, GM-CSF/IL-6/PGE2 M-MDSC displayed a lower capacity to induce TGF-β-producing FoxP3
regulatory Treg compared to GM-CSF/IL-6 M-MDSC, as a consequence of reduced IDO-1 expression. In contrast, GM-CSF/IL-6/PGE2 M-MDSC potentiated IL-10 production by CD8
T, Th2, and particularly CD4
FoxP3
type 1 Treg, the latter of which depended on ILT3 and ILT4 expression. Cumulatively, PGE2 potentiated the suppressive phenotype and functions of GM-CSF/IL-6-induced M-MDSC and changed the mechanisms involved in Treg induction, which could be important for investigating new therapeutic strategies focused on MDSC-related effects in tumors and autoimmune diseases.
Peripheral nerve injury (PNI) triggers a complex multi-cellular response involving the injured neurons, Schwann cells (SCs), and immune cells, often resulting in poor functional recovery. The aim of ...this study was to investigate the effects of the treatment with vitamin B (B1, B2, B3, B5, B6, and B12) complex on the interaction between macrophages and SCs during the recovery period after PNI. Transection of the motor branch of the femoral nerve followed by reconstruction by termino-terminal anastomosis was used as an experimental model. Isolated nerves from the sham (S), operated (O), and operated groups treated with the B vitamins (OT group) were used for immunofluorescence analysis. The obtained data indicated that PNI modulates interactions between macrophages and SCs in a time-dependent manner. The treatment with B vitamins complex promoted the M1-to M2-macrophage polarization and accelerated the transition from the non-myelin to myelin-forming SCs, an indicative of SCs maturation. The effect of B vitamins complex on both cell types was accompanied with an increase in macrophage/SC interactions, all of which correlated with the regeneration of the injured nerve. Clearly, the capacity of B vitamins to modulate macrophages-SCs interaction may be promising for the treatment of PNI.
Proinflammatory and immunoregulatory cytokines are important for the pathogenesis of periapical lesions. However, little is known about how their functions are balanced and controlled at different ...phases of lesion development. The aim of this study was to examine the relationship between the production of Th1, Th2, Th17 and T regulatory cell (T reg) cytokines by human periapical lesion mononuclear cells (PL-MNC) in culture and their correlation with cellular composition and clinical presentation of the lesions. We show that symptomatic lesions are characterized by the infiltration of neutrophils, high production of IL-17, positive correlation between IL-17 and IFN-γ, but not between IL-17 and IL-23 production. Most IL-17
+ cells coexpressed IFN-γ. Asymptomatic lesions were phenotypically heterogeneous. The lesions with the predominance of T cells over B cells/plasma cells expressed higher levels of IFN-γ which correlated with higher production of IL-12 and the frequency of macrophages. In contrast, in most B-type lesions higher levels of IL-5 and TGF-β were observed, as well as positive correlation between the production of TGF-β and IL-10. The addition of Th cytokines in PL-MNC cultures confirmed that Th1, Th2 and Th17 cytokines are mutually antagonistic, except that IL-17, unexpectedly, augmented the production of IFN-γ. IL-10 and TGF-β inhibited the production of both Th1 and Th17 cytokines. Dendritic cells (DCs) from periapical lesions, composed of immature (CD83
−), and mature (CD83
+) myeloid type DCs and plasmacytoid (BDCA2
+) DCs produced higher levels of IL-12 and IL-23 but lower levels of IL-10 and TNF-α than monocyte (Mo) -derived DCs. IL-23 stimulated the production of IL-17 by PL-MNC, whereas the secretion of IFN-γ was enhanced by both IL-12 and IL-23. Cumulatively, these results suggest that: (1) Th1 immune response is most probably important for all stages of periapical lesion development; (2) Th2 and immunoregulatory cytokines are more significant for advanced types of lesions with the predominance of B cells/plasma cells; (3) Th17 immune response seems to play a dominant role in exacerbating inflammation.
Graphene quantum dots (GQD) are atom-thick nanodimensional carbon sheets with excellent physico-chemical and biological properties, making them attractive for application in theranostics. However, ...their immunoregulatory properties are insufficiently investigated, especially in human primary immune cells. We found that non-toxic doses of GQD inhibit the production of proinflammatory and T helper (Th)1 cytokines, and augment the production of anti-inflammatory and Th2 cytokines by human peripheral blood mononuclear cells. While unable to affect T cells directly, GQD impaired the differentiation and functions of monocyte-derived dendritic cells (DC), lowering their capacity to stimulate T cell proliferation, development of Th1 and Th17 cells, and T-cell mediated cytotoxicity. Additionally, GQD-treated DC potentiated Th2 polarization, and induced suppressive CD4+CD25highFoxp3+ regulatory T cells. After internalization in a dynamin-independent, cholesterol-dependent manner, GQD lowered the production of reactive oxygen species and nuclear translocation of NF-κB in DC. The activity of mammalian target of rapamycin (mTOR) was reduced by GQD, which correlated with the increase in transcription of autophagy genes and autophagic flux in DC. Genetic suppression of autophagy impaired the pro-tolerogenic effects of GQD on DC. Our results suggest that GQD-triggered autophagy promotes tolerogenic functions in monocyte-derived DC, which could be beneficial in inflammatory T-cell mediated pathologies, but also harmful in GQD-based anti-cancer therapy.
Aim
Even though IL‐6 is a key inflammatory cytokine in periapical lesions (PLs), its function in stable periapical disease is unknown. Therefore, the aim of this study was to investigate the ...following: first, the ex vivo production of IL‐6 by clinically different PLs; next, subsets of immune cells expressing IL‐6 in PLs according to their inflammatory status and finally, modulatory effect of IL‐6 on T‐cell cytokine production in cell cultures.
Methodology
Inflammatory cells were isolated from a total of 95 human PLs. Detection of IL‐6+ cells within the myeloid and lymphoid populations was performed by multicolour flow cytometry. ELISA and FlowCytomix Microbeads Assay were used to measure cytokine levels in culture supernatants. To study the role of IL‐6 in PLs, mononuclear cells (MNC) from symptomatic (Sy) or asymptomatic (Asy) PLs were treated with IL‐6 or Tocilizumab, an IL‐6R blocking antibody. The differences between groups were tested by unpaired t‐test, Mann–Whitney or Friedman tests.
Results
The levels of IL‐6 in PL MNC culture supernatants were significantly higher compared with total PL cells and PL granulocytes (p < .001). MNC from Sy PLs produced significantly higher levels of IL‐6 than MNC from Asy PLs (p < .001). Flow cytometry analysis showed that NKT cells, CD8+ T cells and M2 macrophages (MØ), were dominant IL‐6+ cells, in contrast to CD4+ T cells. However, CD8+ and CD4+ T cells contributed the most to IL‐6 production. IL‐6hi producing MNC cultures had higher levels of Th1 (IFN‐γ), Th17 (IL‐17A), Tfh (IL‐21) and RANKL, whereas Th2 (IL‐4) and Tregs cytokines (IL‐10, TGF‐β) were lower compared with IL‐6low‐producing cultures. Exogenous IL‐6 stimulated 17A, IL‐21 and RANKL, independently of PL activation status, but decreased IFN‐γ, IL‐4 and IL‐33 levels in IL‐6hi‐producing cultures. Tocilizumab increased IL‐10 and TGF‐β in IL‐6low‐producing cultures. All differences were p < .05.
Conclusions
Most immune cells from Sy PLs expressed higher levels of IL‐6 compared with Asy PLs, which correlated with IL‐6 production in culture. Analysis of cytokines suggested a dominant pro‐inflammatory T‐cell response and osteodestructive function of IL‐6 in PLs judging by Th17/Tfh cell activation, Tregs inhibition and increased RANKL/OPG ratio. Excessive IL‐6 production decreased Th1/Th2 responses.
Alpha-ketoglutarate (αKG) emerged as a key regulator of energetic and redox metabolism in cells, affecting the immune response in various conditions. However, it remained unclear how the exogenous ...αKG modulates the functions of dendritic cells (DCs), key cells regulating T-cell response. Here we found that non-toxic doses of αKG display anti-inflammatory properties in human APC-T cell interaction models. In a model of monocyte-derived (mo)DCs, αKG impaired the differentiation, and the maturation of moDCs induced with lipopolysaccharide (LPS)/interferon (IFN)-γ, and decreased their capacity to induce Th1 cells. However, αKG also promoted IL-1β secretion by mature moDCs, despite inflammasome downregulation, potentiating their Th17 polarizing capacity. αKG induced the expression of anti-oxidative enzymes and hypoxia-induced factor (HIF)-1α in moDCs, activated Akt/FoxO1 pathway and increased autophagy flux, oxidative phosphorylation (OXPHOS) and glycolysis. This correlated with a higher capacity of immature αKG-moDCs to induce Th2 cells, and conventional regulatory T cells in an indolamine-dioxygenase (IDO)-1-dependent manner. Additionally, αKG increased moDCs' capacity to induce non-conventional T regulatory (Tr)-1 and IL-10-producing CD8+T cells via up-regulated immunoglobulin-like transcript (ILT3) expression in OXPHOS-dependent manner. These results suggested that exogenous αKG-altered redox metabolism in moDCs contributed to their tolerogenic properties, which could be relevant for designing more efficient therapeutic approaches in DCs-mediated immunotherapies.
Gold nanoparticles (GNPs) have been investigated extensively as drug carriers in tumour immunotherapy in combination with photothermal therapy. For this purpose, GNPs should be stabilised in ...biological fluids. The goal of this study was to examine how stabilisation agents influence cytotoxicity and immune response in vitro. Spherical GNPs, 20 nm in size, were prepared by ultrasonic spray pyrolysis (USP). Three types of stabilising agents were used: sodium citrate (SC), polyvinyl-pyrrolidone (PVP), and poly-ethylene glycol (PEG). Pristine, non-stabilised GNPs were used as a control. The culture models were mouse L929 cells, B16F10 melanoma cells and human peripheral blood mononuclear cells (PBMNCs), obtained from healthy donors. Control SC- and PEG-GNPs were non-cytotoxic at concentrations (range 1-100 µg/mL), in contrast to PVP-GNPs, which were cytotoxic at higher concentrations. Control GNPs inhibited the production of IFN-ϒ slightly, and augmented the production of IL-10 by PHA-stimulated PBMNC cultures. PEG-GNPs inhibited the production of pro-inflammatory cytokines (IL-1, IL-6, IL-8, TNF-α) and Th1-related cytokines (IFN-ϒ and IL-12p70), and increased the production of Th2 cytokines (IL-4 and IL-5). SC-PEG inhibited the production of IL-8 and IL-17A. In contrast, PVP-GNPs stimulated the production of pro-inflammatory cytokines, Th1 cytokines, and IL-17A, but also IL-10. When uptake of GNPs by monocytes/macrophages in PBMNC cultures was analysed, the ingestion of PEG- GNPs was significantly lower compared to SC- and PVP-GNPs. In conclusion, stabilisation agents modulate biocompatibility and immune response significantly, so their adequate choice for preparation of GNPs is an important factor when considering the use of GNPs for application in vivo.
Cu–Al–Ni shape memory alloys (SMAs) have been investigated as materials for medical devices, but their biomedical application is still limited. The aim of this work was to compare the microstructure, ...corrosion and cytotoxicity in vitro of a Cu–Al–Ni SMA. Rapidly solidified (RS) thin ribbons, manufactured via melt spinning, were used for the tests. The control alloy was a permanent mould casting of the same composition, but without shape memory effect. The results show that RS ribbons are significantly more resistant to corrosion compared with the control alloy, as judged by the lesser release of Cu and Ni into the conditioning medium. These results correlate with the finding that RS ribbons were not cytotoxic to L929 mouse fibroblasts and rat thymocytes. In addition, the RS ribbon conditioning medium inhibited cellular proliferation and IL-2 production by activated rat splenocytes to a much lesser extent. The inhibitory effects were almost completely abolished by conditioning the RS ribbons in culture medium for 4weeks. Microstructural analysis showed that RS ribbons are martensitic, with boron particles as a minor phase. In contrast, the control Cu–Al–Ni alloy had a complex multiphase microstructure. Examination of the alloy surfaces after conditioning by energy dispersive X-ray and Auger electron spectroscopy showed the formation of Cu and Al oxide layers and confirmed that the metals in RS ribbons are less susceptible to oxidation and corrosion compared with the control alloy. In conclusion, these results suggest that rapid solidification significantly improves the corrosion stability and biocompatibility in vitro of Cu–Al–Ni SMA ribbons.
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