IADR Abstract Archives
Effect of Vitamin D3 on CD4+ T Lymphocytes in the Presence of Human Periodontal Ligament Stem Cells and Interferon-γ
Objectives: Human periodontal ligament stem cells (hPDLSCs) possess immunomodulatory ability, which is enhanced by inflammatory cytokines. Among others, hPDLSCs inhibit CD4+ T cell proliferation and stimulate Treg formation. Vitamin D3 inhibits function of CD4+ T cell and modulates the inflammatory response in hPDLCs. However, the combined effect of vitamin D3 and hPDLSCs on immune cells has never been investigated. Therefore, we analyzed combined effect of vitamin D3 and hPDLSCs on CD4+ T cell proliferation and CD4+ FoxP3+ CD25+ Tregs formation in an in vitro co-culture model in the presence and in the absence of inflammatory stimuli. Further, we investigated the influence of vitamin D3 on the expression of immunomodulatory proteins in hPDLSCs, involved in the interplay with CD4+ T cells.
Methods: Allogenic CD4+ T cells were activated by phytohemagglutinin and co-cultured with hPDLCs for 5 days. The experiments were performed in the presence or in the absence of IFN-γ. T cell proliferation was assessed by CFSE labelling and Tregs differentiation by CD4, CD25 and FoxP3 immunostaining, followed by flow cytometry analysis. Additionally, the expression of immunomodulatory factors indolamine-2,3-dioxygenase (IDO), prostaglandin-E2 (PGE-2), protein death ligand 1 (PD-L1) in hPDLCs was assessed.
Results: 1,25(OH)2D3 suppressed CD4+ T cell proliferation and triggered Tregs differentiation in the absence of hPDLCs. CD4+ T proliferation was suppressed by hPDLSCs and further suppressed after addition of IFN-γ. In the presence of hPDLSCs, 1,25(OH)2D3 had no effect on CD4+ T proliferation. Moreover, in the presence of hPDLSCs and IFN-γ, addition of 1,25(OH)2D3 resulted in the activation of CD4+T cell proliferation. Furthermore, under these conditions 1,25(OH)2D3 decreased CD4+ FoxP3+ CD25+ Tregs formation. IFN-γ induced expression of immunomodulatory factors in hPDLSCs was significantly suppressed by 1,25(OH)2D3 in a concentration dependent manner.
Conclusions: In summary, vitamin D3 exerts different effects on the local CD4+ T cell response depending on the presence of hPDLCs and the microenvironment. Therefore, the exact role of vitamin D3 in the local inflammatory response during periodontitis and its therapeutic potential should be further clarified.
Methods: Allogenic CD4+ T cells were activated by phytohemagglutinin and co-cultured with hPDLCs for 5 days. The experiments were performed in the presence or in the absence of IFN-γ. T cell proliferation was assessed by CFSE labelling and Tregs differentiation by CD4, CD25 and FoxP3 immunostaining, followed by flow cytometry analysis. Additionally, the expression of immunomodulatory factors indolamine-2,3-dioxygenase (IDO), prostaglandin-E2 (PGE-2), protein death ligand 1 (PD-L1) in hPDLCs was assessed.
Results: 1,25(OH)2D3 suppressed CD4+ T cell proliferation and triggered Tregs differentiation in the absence of hPDLCs. CD4+ T proliferation was suppressed by hPDLSCs and further suppressed after addition of IFN-γ. In the presence of hPDLSCs, 1,25(OH)2D3 had no effect on CD4+ T proliferation. Moreover, in the presence of hPDLSCs and IFN-γ, addition of 1,25(OH)2D3 resulted in the activation of CD4+T cell proliferation. Furthermore, under these conditions 1,25(OH)2D3 decreased CD4+ FoxP3+ CD25+ Tregs formation. IFN-γ induced expression of immunomodulatory factors in hPDLSCs was significantly suppressed by 1,25(OH)2D3 in a concentration dependent manner.
Conclusions: In summary, vitamin D3 exerts different effects on the local CD4+ T cell response depending on the presence of hPDLCs and the microenvironment. Therefore, the exact role of vitamin D3 in the local inflammatory response during periodontitis and its therapeutic potential should be further clarified.