SDF-1α Regulates The Expressions Of MiRNA-133 Of Mesenchymal Stem Cell In Up-regulating Regular B Cells Differentiation In ITP Patients

Background:Immune thrombocytopenia is a kind of autoimmune disease mainly manifested by hemorrhage.There are a variety of abnormalities in the function and quantity of immunomodulatory cells in ITP patients,among which the pathogenic antibodies produced by the self-reactive B cells can mediate the destruction of platelets.Mesenchymal stem cells have the property of immunomodulation,and have been used to control the immune response in clinical cases.Subsets with immunoregulatory functions also exist in B cells,which may be one of the targets of immune regulation by mesenchymal stem cells.Objective:To investigate the mechanism of mesenchymal stem cells in regulating the differentiation of peripheral blood mononuclear cell into regulatory B cell subsets in peripheral blood of ITP patients under the action of SDF-la.Methods:Collecting the peripheral blood from ITP patients or CD24hi/CD19+CD38hi cells from CD19+B cells by using flow cytometry,and content measured the IL-10 contentin the supernatant by ELISA.Changes in the content of miRNA-133 in mesenchymal stem cells stimulated by SDF-la were determined by q-PCR,and the mesenchymal stem cells transfected with miRNA-133 inhibitor were further co-cultured with PBMC from ITP patients.Changes in the subsets of PBMC before and after culture were detected by flow cytometry.normal control,we then measured the proportion of the IL-10 expression cells(the B10)and theResults:In the CD19+B cells population of ITP patients,the proportion of both CD19/CD24hi/CD38hi cells and B10 decreased(2.40±0.62%vs 8,12±1.21%,2.11±0.35%vs 6.02±0.44%,P<0.05)compared with that of normal controls.After co-culture with mesenchymal stem cells,the proportion of CD19/CD24hi/CD38hi cells and B10 increased(5.78±0.86%vs 2.44±0.58%,5.42±0.53%vs 2.01±0.46%,P<0.05)and the content of IL-10 in the supernatant also increased(830.55±70.71 pg/ml vs 180.06±23.11 pg/ml,P<0.05).The expression of miRNA-133 in mesenchymal stem cells increased after stimulation with SDF-1α(3.64±0.30).After transfected miRNA-133 inhibitor into mesenchymal stem cells,the MSCs cocultured with the PBMC compared with the MSCs no transfected with the miRNA-133 inhibitor,the transfected MSCs showed a poor ability to induce the differentiation of PBMC to B10 as well as a poor ability to induce the differentiation of CD19/CD24hi/CD38hi cells(3.21±0.54%vs 5.78±0.86%;2.1±0.33%vs 5.02±0.57%,P<0.05).Conclusions:The proportion of regulatory B cells in peripheral blood mononuclear cells in ITP patients was lower than that in normal controls,suggesting that the regulatory B cell subsets were reduced in TIP patients.Mesenchymal stem cells could induce regulatory B cell subsets in CD19+B cells from ITP patients.After stimulation of SDF-1α(0.1 ug/ml),an elevation of miRNA-133 was showed in the mesenchymal stem cells.Reducing the expression of miRNA-133 by transfecting the miRNA-133 inhibitor in umbilical cord-derived mesenchymal stem cells can reduce its ability to induce regulatory B cell differentiation in PBMC,indicating that SDF-1α(0.1 ug/ml)can affect the differentiation of PBMC to regular B cells by up-regulating the expression of miRNA-133.