Browsing by Author "Ozdemir R.B.O."
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Item The effects of preconditioning with IFN-γ, IL-4, and IL-10 on costimulatory ligand expressions of mesenchymal stem cells(Kare Publishing, 2021) Ozdemir A.T.; Oztatlici M.; Ozdemir R.B.O.; Cakir B.; Ozbilgin K.; Dariverenli E.; Kirmaz C.Objectives: Mesenchymal stem cells (MSCs) are strong immunomodulatory cells, and co-stimulation may play an important role in increasing the effects of MSCs on adaptive immune cells. Preconditioning may add to the effectiveness of MSCs. The aim of this study was to investigate alterations in the costimulatory ligand expressions of MSCs preconditioned with inflammatory cytokines. Methods: MSCs were preconditioned with interferon gamma (IFN-γ), interleukin (IL) 4 (IL-4), and IL-10, and changes in CD80, CD86, CD137L, CD252, CD274, CD275, and human leukocyte antigen (HLA) class I and II expressions were analyzed using flow cytometry and quantitative polymerase chain reaction methods. Human acute monocytic leukemia cell line (THP-1) macrophages preconditioned under the same conditions served as a control for comparison. Results: The frequencies of CD80 (p=0.0003), CD86 (p<0.0001), CD137L (p<0.0001), CD252 (p=0.0003), CD274 (p=0.0077), CD275 (p<0.0001), and HLA-II (p<0.0001)-positive MSCs was significantly lower than that of the THP-1 macrophages with either method, but there was no significant difference in the HLA-I (p=0.1506) cells. Comparison of the expression of the costimulatory ligands revealed that the expression of MSCs was significantly lower than that of THP-1 cells, and was not affected by cytokine stimuli. Conclusion: The study data indicated that although MSCs are strong immunomodulatory cells, the costimulatory li-gand expression required for an effective antigen presentation was extremely low compared with that of professional antigen presenting cells. In addition, preconditioning with IFN-γ, IL-4, and IL-10 failed to increase the expression of important costimulatory ligands, such as CD80 and CD86, in MSCs. The stability of costimulatory ligand expression suggests that MSCs may be an effective source for HLA-I-mediated peripheral tolerance. © 2021 by International Journal of Medical Biochemistry.Item In-vitro evaluation of effects of mesenchymal stem cells on tlr3, tlr7/8 and tlr9-activated natural killer cells(Kare Publishing, 2021) Ozdemir A.T.; Kirmaz C.; Ozdemir R.B.O.; Degirmenci P.; Oztatlici M.; Degirmenci M.Objectives: In this study, it was aimed to investigate the immunomodulatory effects of Mesenchymal stem cells (MSCs) on Natural Killer (NK) cells activated by Toll-like receptor (TLR) agonists. Methods: MDA-MB-231, MCF-7 and NK-92 cells were induced with TLR3, TLR7/8 and TLR9 agonists and co-cultured with MSCs. Alterations in IFN-γ, TNF-α, Granzyme-b and Perforin expressions were determined by qPCR method, CD69 and CD107a expressions were determined by flow cytometry, and cytotoxicity was determined by MTT-assay. Results: All TLR agonists significantly increased the expressions of the IFN-γ, TNF-α, Granzyme-b, Perforin, CD69 and CD107a in-vitro. We determined that the cytokine, cytotoxic molecules, and activation markers of NK-92 cells interact-ing with breast tumor cells significantly increased by TLR3 and TLR9 agonists. However, suppression rather than activation occurred on the NK-92 cells due to the simultaneous induction of the immunosuppressive effects of MSCs by these agonists. On the other hand, the TLR7/8 agonists provided a low NK-92 induction, however, the inhibitory effects of MSCs were not triggered. Therefore, it provided a more significant activation than TLR3 and TLR9 agonists. Conclusion: Our findings suggested that TLR7/8 agonists may be a better choice to induce antitumor effects of NK cells in a tumor tissue rich in MSCs. © 2021 by Eurasian Journal of Medicine and Oncology.Item In-Vitro Evaluation of Immunomodulation Effects of Mesenchymal Stem Cell-Derived Exosomes in Refractory Chronic Spontaneous Urticaria(Bilimsel Tip Yayinevi, 2023) Ozdemir A.T.; Kirmaz C.; Ozdemir R.B.O.; Oztatlici M.; Sonmez P.K.; Tuglu M.I.Objective: Approximately half of chronic spontaneous urticaria (CSU) patients are thought to have an autoimmune pathology, and they are resistant to current treatment approaches. Mesenchymal stem cells (MSCs) are adult cells that have been shown to be useful in many autoimmune pathologies due to their immunomodulation properties. This study aimed to investigate the immunomodulatory effects of MSCs, and exosomes isolated from refractory CSU patients. Materials and Methods: Peripheral blood mononuclear cells (PBMCs) were isolated from 5 refractory CSU patients and 5 healthy volunteers. The effects of MSCs isolated from CSU patients and healthy MSCs were compared. Co-culture experiments were performed to evaluate the efficacy of Mesenchymal Stem Cells and exosomes on PBMCs of CSU patients and healthy volunteers. To compare the resulting effects, changes in IFN-γ, IL-4, IL-10, IL-17a, and TGF-β cytokines were detected by the ELISA method. Cell proliferations were detected with the CCK-8 kit. Results: The effects of autologous and allogeneic MSCs on IFN- γ expressions were similar, both providing significant suppression at all cell ratios. However, IL-4 and IL-10 expression of PBMCs co-cultured with allogeneic MSCs significantly decreased while IL-17a and TGF-β expression increased significantly. In addition, our findings indicated that exosomes were capable of significant suppression at low PBMC ratios, regardless of autologous or allogeneic origin, but MSCs were more effective as the number of PBMCs increased. Conclusion: These preliminary findings from in-vitro experiments suggested that allogeneic MSC, or high-dose exosome administration may be a potential approach for treatment in CSU patients, most of whom are regarded as suffering from an autoimmune disease and resistant to current treatments. However, our findings need to be supported by clinical studies. Copyright © 2023 The Author(s).