1,25(OH)D Differently Affects Immunomodulatory Activities of Mesenchymal Stem Cells Depending on the Presence of TNF-α, IL-1β and IFN-γ.

Periodontal ligament-derived mesenchymal stem cells (hPDLSCs) possess immunomodulatory abilities which are strongly enhanced by various inflammatory cytokines. Vitamin D has anti-inflammatory effects on hPDLSCs and immune cells. However, no study to date has directly compared the influence of 1,25(OH)D on the immunomodulatory activities of hPDLSCs in the presence of different cytokines. In the present study, the effects of hPDLSCs treated with tumor necrosis factor (TNF)-α, interleukin (IL)-1β, or interferon (IFN)-γ in the presence of 1,25(OH)D on the proliferation of allogenic CD4 T lymphocyte or on the functional status of primary CD68 macrophages were analyzed in coculture models. Additionally, the effects of 1,25(OH)D on TNF-α-, IL-1β-, and IFN-γ-induced gene expression of some immunomodulatory factors in hPDLSCs were compared. Under coculture conditions, 1,25(OH)D increased or decreased CD4 T lymphocyte proliferation via hPDLSCs, depending on the cytokine. hPDLSCs primed with 1,25(OH)D and different cytokines affected pro- and anti-inflammatory cytokine expression in macrophages variably, depending on the priming cytokine. With one exception, 1,25(OH)D significantly reduced TNF-α-, IL-1β-, and IFN-γ-induced expression of all the investigated immunomediators in hPDLSCs, albeit to different extents. These results suggest that 1,25(OH)D influences the immunomodulatory activities of hPDLSCs depending qualitatively and quantitatively on the presence of certain inflammatory cytokines.