The immunomodulatory roles of supracrestal gingival connective tissue-derived human mesenchymal stromal cells in the polarization of macrophages

Abstract

MSCs exert their immunomodulatory effects on various immune cells by cell-cell contact and cytokines secretion. Our previous study has demonstrated that supracrestal gingival connective tissue-derived mesenchymal stem cells (SG-MSCs) were recognized to be a good candidate for periodontal regeneration. SG-MSCs showed the similar potential to PDL-MSCs and held significant advantage over PDL-MSCs by which a tooth extraction is not required. In terms of immunomodulatory properties, the effect of SG-MSCs on macrophage has never been explored. This study was aimed to investigate the effects of SG-MSCs on macrophages by cocultured SG-MSCs and THP-1-derived macrophages (THP-1-MPs) in direct cell-cell contact condition. Briefly, phorbol 12-myristate 13-acetate (PMA) differentiated THP-1 macrophages were prepared in 6-well plate then SG-MSCs were added directly into 6-well plate at different proportions of 0:1, 0.1:1, 1:1 and 1:0 for 72 hours. THP-1-MPs and supernatants were collected after 72 hours and analyzed by flow cytometry and Enzyme-linked Immunoabsorbent Assay (ELISA). The results showed that the expression of IL-10 and TGF-β were upregulated, while TNF-α was downregulated significantly (p<0.05) after co-cultured. However, the alteration in expression of either CD80 (M1 marker) or CD206 (M2 marker) in THP-1 macrophages could not be observed. This study has presented for the first time the role of SG-MSCs on aninhibition of TNF-α secretion and an increase of IL-10 and TGF-β secretion suggesting a potential candidate of SG-MSCs in controlling inflammation of periodontitis and enhancing periodontal regeneration.