Role of bone marrow-derived mesenchymal stem cells in reduction of graft-versus-host disease by effecting CD4+CD25+ regulatory T cells in rats / 中国实验血液学杂志

The study was purposed to investigate the effects and mechanism of bone marrow-derived mesenchymal stem cells (MSCs) on graft-versus-host desease (GVHD) after allogeneic hematopoietic stem cell transplantation (allo-HSCT). The model of GVHD in rat had been established by allo-HSCT with donor derived T cells. The occurence of GVHD in recipients was observed in condition with or without donor derived MSC co-transplantation. Effects of MSCs on GVHD were analyzed by model rat survival rate and pathology. Proportions of CD4+CD25+ regulatory T cells were determined by using label spleen lymphocytes and thymocytes with double fluorescent-labeled antibodies and flow cytometry. The results showed that MSCs inhibited the lethal GVHD after HSC co-transplantation and increased the survival rate. The ratio of CD4/CD8 deceased in GVHD group in different levels, as compared with that in the experimental group. The proportion of CD4+CD25+ regulatory T cells of spleen lymphocytes was 31.55 +/- 7.58% and 20.90 +/- 1.90% in experimental and GVHD groups, respectively. Similarly, the proportion of CD4+CD25+ regulatory T cells of thymocytes was 93.20 +/- 2.69% and 57.17 +/- 6.79% in experimental and the GVHD groups, respectively. Meanwhile the proportion of CD4+CD25+ regulatory T cells was higher in experimental group than that in GVHD group. It is concluded that MSCs may prevent the lethal GVHD after allo-HSC co-transplantation and raise the survival rate of model rats by acting on the CD4+CD25+ regulatory T cells in vivo.

Analysis of the different effects of murine bone marrow endothelial cell conditioned medium on the growth of embryonic and adult hematopoietic stem/progenitor cells in vitro / 中国实验血液学杂志

In the present study, the effects of murine bone marrow endothelial cell conditioned medium (mBMEC-CM) on the growth of yolk sac and bone marrow hematopoietic stem/progenitor cells (HSPC) were investigated. Nonadherent cells of yolk sac and bone marrow were collected for semisolid culture assay of CFU-GM and HPP-CFC after being cultured in DMEM with 10% FBS, 10% mBMEC-CM and/or FL (5 ng/ml), TPO (2 ng/ml) for 24 hours. The number of CFU-GM and HPP-CFC was counted by day 7 and 14 respectively. Atlas cDNA Expression Array was used for analysis of cytokine receptor expression of yolk sac and bone marrow HSPC. The results showed that mBMEC-CM could support the expansion of CFU-GM and HPP-CFC in liquid culture system. The expansion effects of mBMEC-CM were enhanced by combination with FL and TPO. mBMEC-CM was more effective on expansion of bone marrow CFU-GM and HPP-CFC than that of yolk sac CFU-GM and HPP-CFC. The differential expression of cytokine receptors were detected between yolk sac and bone marrow HSPC. PDGF-Rbeta, PDGF-Ralpha and corticotropin releasing factor receptor (CRFR) were only expressed in yolk sac hematopoietic cells while IFN-gammaR, GM-CSFR, Dopamine D2R and follicle-stimulating hormone receptor were only expressed in bone marrow hematopoietic cells. In conclusion, mBMEC-CM could support the growth and proliferation of yolk sac and bone marrow HSPC, and this effect was further enhanced by addition of FL and TPO. mBMEC-CM was more effective on expansion of bone marrow HSPC than on expansion of yolk sac HSPC. The comparative study indicated that the different expressions of cytokine receptors existed between yolk sac and bone marrow hematopoietic cells, which might lead to the difference in expansion in vitro between embryonic and adult HSPC.

Effects of murine bone marrow endothelial cell conditioned medium on the growth of yolk sac hematopoietic stem cells and progenitors / 中国医学科学院学报

<p><b>OBJECTIVE</b>To investigate the effects of murine bone marrow endothelial cell conditioned medium (mBMEC-CM) on the growth of yolk sac hematopoietic progenitors.</p><p><b>METHODS</b>The serum-free mBMEC-CM was obtained from subcultures of murine endothelial cell line derived from bone marrow which was established in our laboratory. The murine yolk sacs were harvested on day 8.5 postcoitus (pc) and incubated with 0.1% collagenase in 10% fetal calf serum at 37 degrees C for 40 minutes. Yolk sac cells were incubated in tissue culture dishes at 37 degrees C for 1 hour. Nonadherent cells were collected for semisolid culture assay of granulocyte-macrophage colony forming unit (CFU-GM) and high proliferative potential-colony forming cell (HPP-CFC) after being cultured in DMEM with 10% mBMEC-CM and 10% FBS for 24 hours. The number of CFU-GM and HPP-CFC was counted at day 7 and day 14 respectively.</p><p><b>RESULTS</b>The growth of CFU-GM and HPP-CFC was supported by mBMEC-CM with GM-CSF. mBMEC-CM could induce the proliferation and differentiation of yolk sac hematopoietic stem cells and progenitors in liquid culture system. The percentages of CFU-GM and HPP-CFC compared with the 0 hour control were (119.5 +/- 5.7)% and (130.8 +/- 9.8)% respectively after 24 hours liquid culture (P < 0.05). The expansion effects of mBMEC-CM on CFU-GM and HPP-CFC were enhanced by compounded with flt3 ligand (FL) and thrombopoietin (TPO). The percentages of CFU-GM and HPP-CFC compared with the 0 hour control were (132.0 +/- 6.2)% and (176.9 +/- 12.8)% respectively after 24 hours liquid culture (P < 0.01).</p><p><b>CONCLUSION</b>Murine bone marrow endothelial cell conditioned medium could support the growth and proliferation of yolk sac hematopoitic stem cells and progenitors, and this promoting effect was further enhanced by addition of FL and TPO.</p>

Osteogenic differentiation of murine yolk sac mesenchymal stem cells in vitro / 中国医学科学院学报

<p><b>OBJECTIVE</b>To investigate the potential of yolk sac mesenchymal stem cells in osteogenic differentiation.</p><p><b>METHODS</b>Murine yolk sacs were harvested on day 8.5 postcoitus, yolk sac cells were obtained after the yolk sacs were digested by 0.1% type I collagenase for 1 hour, the non-adherent cells were removed after being cultured for 1 hour. The adherent cells were cultured in DMEM containing of 5 ng/ml bFGF and 15% FBS, and passaged when they became subconfluent. The morphologic characteristics, and AKP, BMP-2, as well as type I, III collagen of the yolk sac adherent cells were observed and tested. The attached cells were treated with 10(-8) mol/L dexamethasone, 10 mmol/L beta-glycerophosphate, and 50 micrograms/ml vitamin C at passage 4. Alternations of morphological characteristic, AKP activity, collagen of type I, III and mineralization were detected.</p><p><b>RESULTS</b>Pure mesenchymal stem cells which were of spindle shape, uniform in size, positive in type I, III collagen staining and weak positive in AKP activity could be induced to pleomorphism osteoblast-like cells in vitro. The cells were transformed from spindle shape to polygonal cells which were positive in type I collagen, negative in type III collagen, strong positive in BMP-2, and positive in Von Kossa's stain at week 8. The polygonal cells could form nodular structure and their AKP activity was increased. All these were coincidence with the characters of osteoblast.</p><p><b>CONCLUSION</b>Yolk sac mesenchymal stem cell can be purified and induced to osteoblast in vitro.</p>

Osteogenic and neurogenic differentiation of human yolk sacm esenchymal stem cells / 中国病理生理杂志

AIM: To purify human yolk sac mesenchymal ste m cells (hYS-MSC) and investigate its osteogenic and neurogenic differentiation potentials. METHODS: hYS-MSC were separated from yolk sac and purified via p assage culture. The karyotype of hYS-MSCs was analyzed via G-banded characterist ics. Flow cytometric analysis was used to determine the cell cycle and phenotype of hYS-MSC. The AKP expression of hYS-MSC was also tested. Osteogenic different iation of hYS-MSCs was induced by 10 -8mol/L dexamethasone, 10 mmol/L ?-gl ycerophosphate and 50 mg/L vitamin C. Alizarin red S stain was used for identifi cation of mineralization. ?-mecaptoethanol or salviae miltiorrhizae were used t o induce neurogenic differentiation of hYS-MSCs. The expressions of NSE, NF and GFAP were identified by immunohistochemical method. RESULTS: hYS-MSCs could be purified at passages 2 or 3. The cell cycle analysis suggested that hYS-MSCs showed strong proliferational potentials by which the cells kept normal diploid karyotype during the in vitro cultur e. Flow cytometry showed the phenotype of purified hYS-MSCs was uniformly positi ve for CD29, CD44, CD105, and CD166, and negative for reactivity to antigens CD3 4, CD45, or CD86. hYS-MSCs were weakly but clearly positive in AKP. Osteogenic d ifferentiation was appeared after induction of osteogenic differentiation. hYS-M SCs, which were of spindle shape, uniform in size, were induced to pleomorphism osteoblast-like cells which expressed high level of AKP. Aggregates or nodules w ere formed at day 7 and calcium accumulation was detected by alizarin red S stai ning on day 10 or day 14. Neurogenic differentiation of hYS-MSCs was induced by ?-mecaptoethanol or salviae miltiorrhizae. NSE, NF or GFAP positive cells were detected by immunohistochemical staining. CONCLUSIONS: hYS-MSCs have strong proliferation potential and th e normal diploid karyotype is kept during the in vitro culture. The phenoty pe of hYS-MSCs is coincident with adult hMSCs. hYS-MSCs could be induced to dif ferent iate into osteogenic or neurogenic cells.