Browsing by Author "Karaöz, E"

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    Age-related changes in the immunomodulatory effects of human dental pulp derived mesenchymal stem cells on the CD4+ T cell subsets
    Özdemir, RBÖ; Özdemir, AT; Kirmaz, C; Sariboyaci, AE; Karaöz, E; Erman, G; Vatansever, HS; Gökmen, NM
    Mesenchymal stem cells (MSCs) are powerful immunomodulatory cells. The effects of the aging on these abilities of MSCs have not been adequately clarified. In this study, alterations in immunomodulatory abilities of MSCs caused by aging were investigated. For this, dental pulp (DP) MSCs and peripheral blood mononuclear cells (PBMCs) of elderly and young donors were co-cultured age-matched and cross. We detected that the effects of DP-MSCs on Th1 and Th2 cells and their specific cytokines IFN-gamma and IL-4 are not affected by aging. However, we observed that young and elderly DP-MSCs have different effects on Th17 and Treg cells. Th17 frequencies of young and elderly PBMCs were significantly increased only by young DP-MSCs, in contrast, Treg frequencies were significantly increased by elderly DP-MSCs. IL-6, IL-17a and HGF levels of both young and elderly PBMCs showed a significant increase only by young DP-MSCs, but TGF-beta levels were significantly increased only by elderly DP-MSCs. The oral cavity is home to a rich microflora. The interactions of dental tissues with this microflora can lead them to acquire different epigenetic modifications. Aging can affect the microflora composition of the oral cavity and change this process in different directions. According to our findings, DP-MSCs are effective cells in the regulation of CD4(+) T cells, and their effects on Th1 and Th2 cells were not affected by aging. However, pleiotropic molecules IL-6 and HGF expressions, which are important in dental and bone tissue regeneration, decreased significantly in elderly DP-MSCs. This situation may have indirectly made a difference in the modulation effects of young and elderly DP-MSCs on the Th17 and Treg cells.
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    The paracrine immunomodulatory interactions between the human dental pulp derived mesenchymal stem cells and CD4 T cell subsets
    Özdemir, AT; Özdemir, RBÖ; Kirmaz, C; Sariboyaci, AE; Halbutogllari, ZSÜ; Özel, C; Karaöz, E
    Mesenchymal stem cells (MSCs) have strong immunomodulatory properties, however these properties may show some differences according to the tissue type of their isolate. In this study we investigated the paracrine interactions between human DP derived MSCs (hDP-MSCs) and the CD4(+) T helper cell subsets to establish their immunomodulatory mechanisms. We found that the CD4(+)-Tbet(+) (Th1) and CD4(+)-Gata3(+) (Th2) cells were suppressed by the hDP-MSCs, but the CD4(+)-Stat3(+) (Th17) and CD4(+)-CD25(+)-FoxP3(+) (Treg) cells were stimulated. The expressions of T cell specific cytokines interferon gamma (IFN-g), interleukin (IL)-4 and IL-17a decreased, but IL-10 and transforming growth factor beta-1 (TGF-b1) increased with the hDP-MSCs. The expressions of indoleamine-pyrrole 2,3-dioxygenase (IDO), prostaglandin E2 (PGE2), soluble human leukocyte antigen G (sHLA-G) derived from hDP-MSCs slightly increased, but hepatocyte growth factor (HGF) significantly increased in the co-culture groups. According to our findings, the hDP-MSCs can suppress the Th1 and Th2 subsets but stimulate the Th17 and Treg subsets. The Stat3 expression of Th17 cells may have been stimulated by the HGF, and thus the pro-inflammatory Th17 cells may have altered into the immunosuppressive regulatory Th17 cells. Further prospective studies are needed to confirm our findings. (C) 2016 Elsevier Inc. All rights reserved.