ABSTRACT
@#【Objective】 To study the mechanisms and therapeutic effects of human olfactory mucosa-derived mesenchymal stem cells（OMSC）on experimental autoimmune encephalomyelitis（EAE）in mice.【Methods】Under local anesthesia by using nasal endoscopy，olfactory epithelia of healthy donors were obtained，digested and cultured up to the 5th passage. OMSC were identified，differentiated and stained. EAE models were induced in C57 female mice by myelin oligodendrocyte glycoprotein（MOG35- 55）and pertussis toxin（PT）. Neurological function was documented daily. On day 16 after immunization（peak of incidence），the mice were divided randomly into two groups and treated with OMSC and PBS via tail vein injection respectively. On day 24 after immunization ，blood was collected from angular vein and levels of IL-10，IL-17，IFN-γ and IL-6 were determined by cytometric beads array（CBA）. The size of the spinal cord lesion in mice was observed and measured by using HE and LFB staining. Peripheral blood lymphocytes（PBL）of healthy donors were obtained and then co-cultured with OMSC. The proportions of CD4+ T cells secreting IFN- γ（Th1 cells）in lymphocyte group and co-culture group were compared after 2 days of cultivation. Adding IDO or COX pathway inhibitor to co- culture group and cultivating for 2 days，we observed and compared the proportions of Th1 cells in lymphocyte group，co-culture group and inhibitor treatment group respectively.【Results】OMSC exhibited certain mesenchymal stem cell-like characteristics with respect to expression of stem cell surface markers and multilineage differentiation potentials. After induced by MOG35- 55 and PT，EAE models showed different levels of neurological damage. Compared with those in PBS treatment group，in OMSC treatment group，the severity of neural dysfunction in mice was significantly reduced（P =0.002），the level of IFN-γ in serum was lower（P = 0.032），but no significant differences in the levels of IL-10，IL-17 and IL-6 were found between two groups. HE and LFB staining revealed that the inflammatory infiltration and demyelinating areas in OMSC treatment group were less than those in PBS treatment group. The proportion of Th1 cells was lower in co-culture group than that in lymphocyte group（P = 0.001），higher in IDO inhibitor group than that in co-culture group（P = 0.01），but no significant difference was found between IDO inhibitor group and lymphocyte group or between COX inhibitor group and co-culture group.【Conclusions】OMSC may regulate the proportion of Th1 lymphocytes through IDO pathway so as to inhibit the demyelinating injuries of EAE in mice. This study provides a new idea for the clinical treatment of multiple sclerosis.
ABSTRACT
@#【Objective】To study the effect of mesenchymal stem cells（MSC）on proliferation and immunomodulation of B cells in vitro.【Methods】Bone marrow 30 mL from healthy donors was isolated by density gradient centrifugation. Isolated MSC were cultivated adherently with L- DMEM medium containing 10% fetal bovine serum（FBS）. Phenotype and differentiation capacity of MSC was detected after the sixth passage. Peripheral blood mononuclear cells（PBMC）of healthy donors were also obtained by density gradient centrifugation. CD19+ B cells were sorted by fluorescence activated and co-cultured with MSC（CD19+ B∶MSC = 5∶1）group. Stimulated by CpG+ CD40L，the proliferation of B cells of two groups were checked 96 hours after co-culture respectively. The CD19+CD5+ B cells percentage and its secretion of IL-10 were detected by FACS. The effects of CD19+ B cells on the proliferation of CD4+ T cells and the secretion of IFN-γ were continually observed. Anti-IL-10 was used to confirm the effect of B cells on proliferation and IFN-γ secretion of CD4+ T cells.【Results】MSC collected from healthy donors remained differentiation capacity. MSC derived from bone marrow expressed CD29，CD44，CD73，CD90，CD105，and CD166，but did not express CD45 and CD34. Compared with control group，the proportion of CD19+ B cells proliferation in co-cultured group was significantly increased after 3 days，meanwhile，the level of IFN-γ，which secreted by CD4+ T cells was significantly restrained. To make a further analysis of the subsets of CD19+ B cells，the percentage of CD5+ B cells in co-cultured group increased from（21.31±1.22）% to（31.27±0.92）%（P=0.014），and its IL-10 secretion increased from（1.09±0.08）% to（2.44±0.06）%（P<0.001）compared with control group. After anti-IL-10 was used，the B cells co-cultured with MSC showed a decreased capacity of inhibiting the proliferation and IFN-γ secretion of CD4+ T cells.【Conclusions】MSC could promote the proliferation of CD19+ B cells to inhibit the secretion of IFN-γ by CD4+ T cells，which may be related to the increasing expression of IL-10 by CD19+CD5+B cells.