Interferon-γ Enhances The Immunoregulatory Activities Of HUC-MSC And Its Transplantation In The Treatment Of Systemic Lupus Erythematosus

Objective: To investigate the effect of IFN-γ-pretreated human umbilical cord mesenchymal stem cells on its anti-inflammtory activities and its transplantation in the treatment of systemic lupus erythematosus in mice.Methods: hUC-MSC was induced by IFN-γ(20ng/ml)or separately cultured for 24 hours,the expression level of Indoleamine 2,3-dioxygenase was determined by Real-time Quantitative PCR Detecting System and Western Blot respectively.24 female Fas-/-mice were randomly divided into 3 groups: PBS group,IFN-γ-uninduced h UC-MSC group,IFN-γ-pretreated h UC-MSC group.Fas-/-mices in the three groups were injected with PBS、IFN-γ-uninduced h UC-MSC(1x106)、 h UC-MSC(1x106)induced by IFN-γ(20ng/ml)for 24 hours,respectively.The level of urine protein in Fas-/-mice was by 24 h urine tested in clinical laboratory.Collecting blood from the eye socket vein in mice to determine serum levels of anti double stranded DNA antibody(ds-DNA)and Disodium5-Guanylate(IMP)by Elisa Kits.Immunohistochemistry was used to detect whether there was immune complex Ig G and C3 deposition in the kidney.The level of CD3+CD4+T cells,CD3+CD8+T cells and CD4+CD25+T cells in blood in Fas-/-mice was detected by flow cytometry.Results:IFN-γ-uninduced hUC-MSC did not express IDO at the RNA level and protein level,but IFN-γ induced IDO expression in h UC-MSC.Ensuring a continuous view of Fas-/-mice for 8 weeks after cell transplantation,we found the level of urine protein,anti double stranded DNA antibody(ds-DNA)and Disodium 5-Guanylate(IMP)in IFN-γ-uninduced h UC-MSC group and IFN-γ-pretreated h UC-MSC group were significantly lower than those in PBS group(P<0.05 or P<0.01).Compared with the untreated,the level of urine protein,anti ds-DNA and IMP in PBS group increased significantly(P<0.05 or P<0.01);there was no significant change in the level of urine protein,ds-DNA and IMP in IFN-γ-uninduced h UC-MSC group(P>0.05);However,the level of urine protein,anti ds-DNA and IMP in IFN-γ-pretreated h UC-MSC group showed a significant downward(P<0.01).There were a large number of Ig G and C3 immune complexes appeared in glomerular mesangial region of Fas-/-mices in PBS group,There were a few number of Ig G and C3 immune complexes appeared in glomerular mesangial region of Fas-/-mices in IFN-γ-uninduced h UC-MSC group,There was no Ig G and C3 immune complexes appeared in glomerular mesangial region of Fas-/-mices in IFN-γ induced h UC-MSC group.The blood level of CD3+CD4+T cells,CD3+CD8+T cells in IFN-γ-uninduced h UC-MSC group compared with those in PBS group without obvious changes(P>0.05),IFN-γ-pretreatedh UC-MSC significantly decreased the blood level of CD3+CD4+T cells,CD3+CD8+T cells in mices(P<0.05 or P<0.01).Compared with PBS group,IFN-γ-uninduced h UC-MSC increased blood level of CD4+CD25+T cells level in mices(P<0.05 or P<0.01),and the blood level of CD4+CD25+T cells in IFN-γ induced h UC-MSC group was significantly higher than that in IFN-γ-uninduced h UC-MSC group(P<0.05 or P<0.01).Conclusion: IFN-γ enhanced the anti-inflammtory activities of h UC-MSC,and the transplantation of IFN-γ-pretreatedh UC-MSC has a better therapeutic effect on SLE in mice.