Прегледај по Аутор "Vučević, Dragana"
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- СтавкаAnti-inflammatory effect of amalgam on periapical lesion cells in culture(Ministry of Defance, Serbia, 2021) Eraković, Mile; Duka, Miloš; Bekić, Marina; Milanović, Marijana; Tomić, Sergej; Vučević, Dragana; Čolić, MiodragBackground/Aim. Amalgam h as b een u sed f or y ears in dentistry, but the controversy on its adverse effects, both on local oral/dental tissues and systemic health, still exists. When used for retrograde filling in apical surgery, amalgam comes in close contact with the periapical tissue, and it is sometimes responsible for the induction of periapical lesion (PL) or its exacerbation. Therefore, the aim of the study was to examine the effect of amalgam on cytotoxicity and production of pro-inflammatory cytokine by cells isolated from PL. Methods. Conditioned medium from freshly prepared amalgam (ACM) was performed according to the ISO 10993-12 by incubating the alloy in RPMI medium (0.2 g/mL) for 3 days at 37°C. Cells were isolated from 20 human PLs after apicoectomy by collagenase/DNA-ase digestion and cultured with different dilutions of ACM. Cytotoxicity was determined by MTT assay (n = 7 cultures) and apoptosis/necrosis assays (n = 8 cultures), whereas cytokine production was measured by a Flow Cytomix Microbeads Assay (n = 8 cultures). Results. Undiluted (100%) and 75% ACM was cytotoxic due to induction of apoptosis of PL cells. Non-cytotoxic concentrations of ACM (50% and 25%) inhibited the production of pro-inflammatory cytokines (TNF-α, IL-1β, IL-6, and IL-8), concentrationdependently. Conclusion. For t he f irst t ime, o ur results showed an unexpected anti-inflammatory property of amalgam on PL cells, which could be beneficial for PL healing after apicoectomy
- СтавкаFecal microbiota composition associates with the capacity of human peripheral blood monocytes to differentiate into immunogenic dendritic cells in vitro(2021) Radojević, Dušan; Tomić, Sergej; Mihajlović, Dušan; Tolinački, Maja; Pavlović, Bojan; Vučević, Dragana; Bojić, Svetlana; Golić, Nataša; Čolić, Miodrag; Đokić, JelenaAlthough promising for active immunization in cancer patients, dendritic cells (DCs) vaccines generated in vitro display high inter-individual variability in their immunogenicity, which mostly limits their therapeutic efficacy. Gut microbiota composition is a key emerging factor affecting individuals’ immune responses, but it is unknown how it affects the variability of donors’ precursor cells to differentiate into immunogenic DCs in vitro. By analyzing gut microbiota composition in 14 healthy donors, along with the phenotype and cytokines production by monocyte-derived DCs, we found significant correlations between immunogenic properties of DC and microbiota composition. Namely, donors who had higher α-diversity of gut microbiota and higher abundance of short-chain fatty acid (SCFAs) and SCFA-producing bacteria in feces, displayed lower expression of CD1a on immature (im)DC and higher expression of ILT-3, costimulatory molecules (CD86, CD40) proinflammatory cytokines (TNF-α, IL-6, IL-8) and IL-12p70/IL-10 ratio, all of which correlated with their lower maturation potential and immunogenicity upon stimulation with LPS/IFNγ, a well-known Th1 polarizing cocktail. In contrast, imDCs generated from donors with lower α-diversity and higher abundance of Bifidobacterium and Collinsella in feces displayed higher CD1a expression and higher potential to up-regulate CD86 and CD40, increase TNF-α, IL-6, IL-8 production, and IL-12p70/IL-10 ratio upon stimulation. These results emphasize the important role of gut microbiota on the capacity of donor precursor cells to differentiate into immunogenic DCs suitable for cancer therapy, which could be harnessed for improving the actual and future DC-based cancer therapies.
- СтавкаFunctionalization-dependent effects of cellulose nanofibrils on tolerogenic mechanisms of human dendritic cells(Dove Medical Press, 2018) Tomić, Sergej; Ilić, Nataša; Kokol, Vanja; Gruden-Movsesijan, Alisa; Mihajlović, Dušan; Bekić, Marina; Sofronić-Milosavljević, Ljiljana; Čolić, Miodrag; Vučević, DraganaBackground: Cellulose nanofibrils (CNF) are attractive nanomaterials for various biomedical applications due to their excellent biocompatibility and biomimetic properties. However, their immunoregulatory properties are insufficiently investigated, especially in relation to their functionalization, which could cause problems during their clinical application. Methods: Using a model of human dendritic cells (DC), which have a central role in the regulation of immune response, we investigated how differentially functionalized CNF, ie, native (n) CNF, 2,2,6,6-tetramethylpiperidine 1-oxyl radical-oxidized (c) CNF, and 3-aminopropylphosphoric acid-functionalized (APAc) CNF, affect DC properties, their viability, morphology, differentiation and maturation potential, and the capacity to regulate T cell-mediated immune response. Results: Nontoxic doses of APAcCNF displayed the strongest inhibitory effects on DC differentiation, maturation, and T helper (Th) 1 and Th17 polarization capacity, followed by cCNF and nCNF, respectively. These results correlated with a specific pattern of regulatory cytokines production by APAcCNF-DC and their increased capacity to induce suppressive CD8+CD25+IL-10+ regulatory T cells in immunoglobulin-like transcript (ILT)-3- and ILT-4-dependent manner. In contrast, nCNF-DC induced predominantly suppressive CD4+CD25hiFoxP3hi regulatory T cells in indolamine 2,3-dioxygenase-1-dependent manner. Different tolerogenic properties of CNF correlated with their size and APA functionalization, as well as with different expression of CD209 and actin bundles at the place of contact with CNF. Conclusion: The capacity to induce different types of DC-mediated tolerogenic immune responses by functionalized CNF opens new perspectives for their application as well-tolerated nanomaterials in tissue engineering and novel platforms for the therapy of inflammatory T cell-mediated pathologies.
- СтавкаPhosphonate-Modified Cellulose Nanocrystals Potentiate the Th1 Polarising Capacity of Monocyte-Derived Dendritic Cells via GABA-B Receptor(Dove Medical Press, 2022) Bekić, Marina; Vasiljević, Miloš; Stojanović, Dušica; Kokol, Vanja; Mihajlović, Dušan; Vučević, Dragana; Uskoković, Petar; Čolić, Miodrag; Tomić, SergejPurpose: Phosphonates, like 3-AminoPropylphosphonic Acid (ApA), possess a great potential for the therapy of bone tumours, and their delivery via cellulose nanocrystals (CNCs) seems a promising approach for their increased efficacy in target tissues. However, the immunological effects of CNC-phosphonates have not been investigated thoroughly. The main aim was to examine how the modification of CNCs with phosphonate affects their immunomodulatory properties in human cells. Methods: Wood-based native (n) CNCs were modified via oxidation (ox-CNCs) and subsequent conjugation with ApA (ApA-CNCs). CNCs were characterised by atomic force microscopy (AFM) and nanoindentation. Cytotoxicity and immunomodulatory potential of CNCs were investigated in cultures of human peripheral blood mononuclear cells (PBMCs) and monocyte-derived dendritic cells (MoDCs)/T cells co-cultures by monitoring phenotype, cytokines production, allostimulatory and Th/Treg polarisation capacity. Results: AFM showed an increase in CNCs' thickens, elasticity modulus and hardness during the modification with ApA. When applied at non-toxic doses, nCNCs showed a tolerogenic potential upon internalisation by MoDCs, as judged by their increased capacity to up-regulate tolerogenic markers and induce regulatory T cells (Treg), especially when present during the differentiation of MoDCs. In contrast, ox- and ApA-CNCs induced oxidative stress and autophagy in MoDCs, which correlated with their stimulatory effect on the maturation of MoDCs, but also inhibition of MoDCs differentiation. ApA-CNC-treated MoDCs displayed the highest allostimulatory and Th1/CTL polarising activity in co-cultures with T cells. These effects of ApA-CNCs were mediated via GABA-B receptor-induced lowering of cAMP levels in MoDCs, and they could be blocked by GABA-B receptor inhibitor. Moreover, the Th1 polarising and allostimulatory capacity of MoDCs differentiated with ApA-CNC were largely preserved upon the maturation of MoDCs, whereas nCNC- and ox-CNC-differentiated MoDCs displayed an increased tolerogenic potential. Conclusion: The delivery of ApA via CNCs induces potent DC-mediated Th1 polarisation, which could be beneficial in their potential application in tumour therapy.
- СтавкаProstaglanin-E2 Potentiates the Suppressive Functions of Human Mononuclear Myeloid-Derived Suppressor Cells and Increases Their Capacity to Expand IL-10-Producing Regulatory T Cell Subsets(Frontiers, 2019) Tomić, Sergej; Joksimović, Bojan; Bekić, Marina; Vasiljević, Miloš; Milanović, Marijana; Čolić, Miodrag; Vučević, DraganaMyeloid-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 in vivo, 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 in vitro. 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-b. These results correlated with an increased potential of GM-CSF/IL-6/PGE2 M-MDSC to suppress T cell proliferation, 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-b-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.
- СтавкаThe Effect of Stabilisation Agents on the Immunomodulatory Properties of Gold Nanoparticles Obtained by Ultrasonic Spray Pyrolysis(MDPI, 2019) Bekić, Marina; Tomić, Serge; Rudolf, Rebeka; Milanović, Marijana; Vučević, Dragana; Anžel, Ivan; Čolić, MiodragGold nanoparticles (GNPs) have been investigated extensively as drug carriers in tumour immunotherapy in combinationwith 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 andimmune response in vitro. SphericalGNPs, 20 nmin size, werepreparedbyultrasonic spraypyrolysis (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 g/mL), in contrast to PVP-GNPs, which were cytotoxic at higher concentrations. Control GNPs inhibited the production of IFN-U 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- ) and Th1-related cytokines (IFN-U 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.