Experimental Study Of Human Gingival Tissue-Derived Mesenchymal Stem Cells In Management Of Chronic Graft-versus-host Disease(GVHD)

Objective: Human gingival tissue-derived mesenchymal stem cells(GMSCs) are a convenient source of MSCs for treating autoimmune disease. In this study, we investigated the advantage of GMSCs compared with BMSCs or ASCs in immune regulation both in vitro and in vivo. Also as B cells play an important role in the pathogenesis of autoimmune disease especially in chronic-GVHD. We set following experiment to investigate the role of GMSCs in B cell directed disease such as chronic-GVHD.Methods: MSCs were derived from indicated human tissues of healthy volunteers. MSCs were cocultured with T cells with the addition of CD3/CD28 beads to test the immune regulating ability of MSCs at different passages in vitro. Also we established xeno-GVHD model using irradiated NOD mice with tail vein injection of PBMCs in vivo. To study the effect of GMSCs to chronic GVHD, B cells were sorted from human peripheral blood mononuclear cells(PBMC). B cells were co-cultured with GMSCs as fibroblast cells were determined as negative controls. Flow cytometry and Elisa were used to determine the expansion and cytokine expression of B cells. Additionally various antibodys for different signal were added to the culture, to scan the signal involved in the GMSCs function. Finally humanrized chronic GVHD model were injected with GMSCs to investigate the in vivo regulation function.Results: GMSCs showed similar expression of various phenotype as BMSCs or ASCs, and it presented stronger suppressive and proliferate ability against T cells expansion in vitro and xeno-GVHD in vivo compared with BMSCs or ASCs even at older passages. GMSCs injection prevented the lethality in humanrized chronic graft-versus-host disease(GVHD) model successfully in vivo. GMSCs regulated the proliferation of B cells and reduced the expression of cytokines and immunoglobulins in vitro. Also, GMSCs regulated B cells lost the antigen presenting ability to T cells which suppressed the proliferation of T cells indirectly. Mechanism study showed that GMSCs suppressed the proliferation of T cells and protected chronic-GVHD both in vitro and vivo via the TGF-β pathway.Conclusions: GMSCs suppressed the expansion, differentiation as well as the cytokine and IgG expressioin of B cells in vitro. In the meanwhile, injection of GMSCs protected the lethality of chronic GVHD. Taken together, these data indicate the potential prophylactic and therapeutic effects of human GMSCs in reducing chronic GVHD and other autoimmune disease.