Immunoregulatory Effects Of Mesenchumal Stem Cells (MSCs) In Systemic Lupus Erythematosus (SLE)

Objective: Immunoregulatory effects of human mesenchymal stem cells (HMSCs) in Systemic lupus erythematosus (SLE) and mouse mesenchymal stem cells (mMSCs) combined with leflunomide(LEF) on mice T-lymphocytes in vitro.Methods: MSCs were isolated from human bone marrow and BALB/c mice bone marrow. (1) The BALB/c mice's splenic lymphocytes were isolated by using EZ-SepTM Mouse 1X. Under ConA stimulating, splenic lymphocytes were pretreated with LEF, then washed and co-cultured with mMSCs. we set up four groups to investigate in this study: group A, splenic lymphocytes alone; group B, splenic lymphocytes with mMSCs; group C, LEF-pretreated splenic lymphocytes alone and the group D, LEF-pretreated splenic lymphocytes with mMSCs. T-lymphocytes' proliferation were assessed by MTT. FCM was used to analysis T-lymphocytes' apoptosis and surface markers.The mRNA expression of interleukm(IL)2,IL-10 were detected by Real-time RT-PCR.(2) The HMSCs (4×10~4,1×10~4) were added into wells containing peripheral blood lymphocytes (2×10~5) from SLE patients in the presence of phytohemagglutinin (PHA). We assessed the proliferation of T-lymphocytes , We also observed the T lymphocytes' apoptosis and the mRNA expression of interferonγ(IFN-γ), interleukin-10 (IL-10), transforming growth factor-β1(TGF-β1). (3) The monocytes were isolated from peripheral blood of SLE patients and cultivated into dendritic cell(DC) with cytokines such as rhGM-CSF and rhIL-4. DC of SLE patients were cocultured with HMSCs. Immunophenotypes (CD86, CD83, HLA-DR, CD1a) of cells were analyzed by FCM. The ability of DC stimulating lymphocytes proliferation was detected by MTT.Results: (1) mMSCs combined with LEF cooperatedly inhibit T-lymphocytes proliferation and the mRNA expression of IL-10. (2) With the presence of HMSCs, SLE patients of peripheral blood T-lymphocytes resulted in a statistically significant decrease of their proliferative activities and apoptosis as dose-dependent manner. HMSCs promote the mRNA expression of TGF-β1and inhibit the mRNA expression of IL-10,IFN-γ。(3) HMSCs strongly inhibited the initial differentiation of DCs from monocytes which from peripheral blood of SLE patients, inhibited the maturation of DCs and induce lymphocytes unresponsiveness.Conclusion:(1) mMSCs combined with LEF show some collaborative immunoregulatory effects on mice's T-lymphocytes.(2) HMSCs can inhibit the proliferative activities and apoptosis of SLE patients peripheral blood T-lymphocytes, higher the mRNA expression of T-lymphocytes' TGF-β1and lower the mRNA expression of IL-10,IFN-γ, inhibit differentiation and function of SLE patients monocyte-derived DC which may play an important role in it's immunoimpressive affects in SLE.