Transplantation of bone marrow mesenchymal stem cells improves motor function in a DMD mouse model

AIM: To observe amelioration of motor function in a Duchenne muscular dystrophy (DMD) mouse model (dko mice) after transplantation of bone marrow mesenchymal stem cells (MSCs). METHODS: Passage fifth MSCs cultured in vitro were transplanted into dko mice by tail vein, motor functions of experimental mice and matched control mice, including traction, rotating rods, rotated wheel, upside down, turning over and walking (all were recorded by Sony digital camera) were tested 15 weeks after transplantation. The fluorescent expression of dystrophin and utrophin in gastrocnemius muscle tissue of dko mice was detected by SABC-Cy3, and average optical density of positive fibers was calculated. RESULTS: MSCs grew in colony over passage third, and there was low immunologic reaction by vein transplantation. There was dystrophin and utrophin fluorescent expression in sarcolemma of dko mice 15 weeks after transplantation, but no any fluorescent expression in controls. There was significant difference in fluorescent average optical density of positive fibers between two groups (P＜0.05). Amelioration of motor functions in dko mice was found 15 weeks after MSCs transplantation compared with the control mice (P＜0.05). CONCLUSION: Transplantation of MSCs ameliorates the positive and passive motor functions of dko mice.     

Transfusion of mesenchymal stem cells improve the hematopoiesis in mice with aplastic anemia by regulating immune cells

AIM: To study the possible immunologic mechanism of mesenchymal stem cells (MSCs) by which the hematopoiesis of mice with aplastic anemia (AA) is improved. METHODS: The mice model of immuno-mediated aplastic anemia was established. Thirty BALB/c mice were divided into 3 groups: radiation group, AA model group and MSCs group. The mice in radiation group only had processing of 5 Gy ［60Co］γ radiation. The mice in AA model group were intravenously injected with the cell suspension of thymocyte and lymph-node cell mixture (prepared from DBA/2 mice, 1×106 cells) after 5 Gy ［60Co］γ radiation. The animals in MSCs group received the same treatment as the mice in AA model group did, and afterwards was injected with 1×106 MSCs intravenously at 3 days. All the mice in the 3 groups were observed and analyzed the following parameters: peripheral blood cells, pathological features of bone marrow, the relation between the changes of peripheral CD4+, CD8+, CD4+/CD8+, NK cells and the hematopoiesis. RESULTS: After 5 Gy ［60Co］γ radiation, the peripheral blood cells in all groups decreased at 7 days, while at 21 days those in MSCs group and radiation group restored to normal but those in AA model group was still at lower level. At 7 days, the cells of CD4+, CD8+ and CD4+/CD8+ in each group were similar without statistical difference, but the number of NK cells in MSCs group was quite lower than that in the other 2 groups (P<0.05). At 14 days, the CD4+ cells in all groups were obviously decreased, while the CD8+ cells in MSCs group and AA model group were significantly higher than those in radiation group. At 21 days, the CD8+ and NK cells in MSCs group were quite the same as those in radiation group while those in AA model group were obviously higher compared to the other 2 groups. The number of adipose cells observed in the pathological slice of femoral bone in MSCs group and radiation group was no difference while that in AA model group was much higher. CONCLUSION: MSCs transfusion improves the hematopoiesis in mice with aplastic anemia by regulating the functions of immune cells.     

The effects of FTY720 on lymphocytes and monocytes in mouse intestinal transplantation

AIM：To test the effects of FTY720 on mouse intestinal allografts.METHODS：C3H mice（H-2k）were used as donor and C57BL/6 mice (H-2b) as recipients.FTY720 group,allogeneic control group and isogeneic control group were set up.6 and 14 days after transplantation,murine intestinal grafts were harvested for histologic assessment.Lymphocytes were collected from mesenteric lymph nodes (MLN),Peyer’s patch (PP),lamina propria lymphocytes (LPL) and intraepithelial lymphocytes (IEL) in the graft,then were analyzed by cytometry.RESULTS：Rejection was inhibited in FTY720 group at the 6th post-transplant day,although not at the 14th day.Recipient CD4+ and CD8+ T cells,CD19+ B cells,as well as γδ TCR lymphocytes,were greatly reduced by FTY720 therapy.The similar action of FTY720 was also revealed in Gr1+CD11b+ monocytes.CONCLUSION：FTY720 is efficient on alleviating allo-immune response by reducing the infiltration of both lymphocytes and monocytes into the graft in a mouse intestinal transplantation model.     

Biological characteristics and induced differentiation of bone marrow-derived mesenchymal stem cells from sensitized mice in vitro

AIM: To evaluate the biological characteristics and differentiating potentials of bone marrow-derived mesenchymal stem cells (MSCs) from sensitized mice by allogeneic splenocyte transfusion in vitro. METHODS: Adherent culture method was applied for culturing the bone marrow-derived MSCs from sensitized mice. The cell morphology was examined and the surface marker profiles were analyzed by flow cytometry. The differentiating potentials of the MSCs into osteogenic, adipogenic and myogenic lineages were explored. The bone marrow-derived MSCs from the normal mice were collected and served as controls. RESULTS: Both the bone marrow-derived MSCs from sensitized and normal mice were exhibited a homogeneous distinctive morphology and were positive for the surface markers CD29, CD105, CD44 and Sca-1, negative in CD 34 and CD11b. The abilities of both MSCs to differentiate into osteogenic, adipogenic and myogenic pathways in the same condition were also observed. CONCLUSION: There is no difference in the biological characteristics and induced differentiating potentials between the sensitized mouse bone marrow-derived MSCs by allogeneic splenocytes transfusion and the MSCs from normal mice.     

Distribution and identification of immunocytes in humanized SCID mouse model

AIM: Humanized-NOD/SCID(hu-NOD/SCID) mouse model was established and the level of immune reconstitution was assessed in this model. METHODS: Mononuclear cells (MNC) and CD34⁺ cells were isolated or sorted from cord blood(CB). Human CD45, CD19, CD3 markers on cells from NOD/SCID murine peripheral blood(PB), bone marrow(BM), thymus were detected by FCM from 4 to 10 weeks after hematopoietic stem cell transplantation. After 10 weeks, the gene expressions of the human β₂M and RAG2 were detected by RT-PCR in PB or bone marrow of mice model. RESULTS: Human CD45, CD19, CD3 cells populations in PB and BM were found by flow cytometry in mice model transplanted with CD34+ cells or CB MNC from 4 to 10 weeks. The highest positivity of human lymphocytes was at 8 week after transplantation. The levels of human cell engraftment in mice transplanted with CD34⁺ cells were higher than those in mice transplanted with CB MNC. The mRNA of human β₂M and RAG2 were found by RT-PCR in BM.CONCLUSION: The higher level of human lymphocyte engraftment is established in NOD/SCID mouse model transplanted with CD34⁺ compared with CB MNC. The maturation of T lymphocytes could be happened in bone marrow of mice model.     

Effect of livin-modified BM-MSCs transplantation on cardiac function following acute myocardial infarction in a rat model

AIM: To study the effect of livin gene-modified bone marrow mesenchymal stem cells(BM-MSCs) transplantation on the cardiac function following acute myocardial infarction in a rat model and the expression of livin, caspase-3, caspase-7 and caspase-9 in the livin gene-modified BM-MSCs. METHODS: The MSCs were obtained by the whole bone marrow culture method, and the apoptosis of the MSCs after infection with adenovirus vector carrying enhanced green fluorescent protein(EGFP) gene and livin recombinant vector(rAd-livin) were detected by flow cytometry. The expression of livin, caspase-3, caspase-7 and caspase-9 was detected by Western blot. After permanent left anterior descending artery occlusion, the rats were randomized to receive intramyocardial injection of DMEM without cells(vehicle group), or containing MSCs(MSCs group), MSCs(EGFP)(rAd-control/MSCs group) or MSCs(livin)(rAd-livin/MSCs group). Left ventricular systolic pressure(LVSP), left ventricular end-diastolic pressure(LVEDP), the maximum increased rate of left ventricular pressure(-dp/dt_max) and the maximum decline rate of left ventricular pressure(+dp/dt_max) were recorded for evaluating the cardiac functions. RESULTS: The apoptosis of rAd-livin/MSCs was significantly decreased as compared with MSCs and rAd-control/MSCs(P<0.05). Meanwhile, the expression of caspase-3, caspase-7 and caspase-9 was significantly downregulated as compared with the other 2 groups(P<0.05). The cardiac function in rAd-livin/MSCs group was significantly improved as compared with DMEM group, and those in the other 2 groups got the similar results, but the function in rAd-livin/MSCs group was better improved. Meanwhile, the number of surviving cells in rAd-livin/MSCs group was significantly improved as compared with the other 2 groups. CONCLUSION: The apoptosis of MSCs is decreased after rAd-livin transfection, and the expression of caspase-3, caspase-7 and caspase-9 is also significantly downregulated while the expression of livin is significantly upregulated. Transplantation of livin-modified BM-MSCs by lentiviral vector results in better prognosis for treating myocardial infarction by enhancing cell survival.     

Lentivirus-mediated calcitonin gene-related peptide transfection enhances endothelial differentiation of rat bone marrow mesenchymal stem cells

AIM：To study the effect of calcitonin gene-related peptide (CGRP) gene transfection mediated by lentivirus on the differentiation of rat bone marrow mesenchymal stem cells (MSCs) to endothelial cells. METHODS：Rat bone marrow MSCs were isolated by density gradient centrifugation combined with adherence method. Recombinant lentivirus vector carrying CGRP gene (Lenti-CGRP) was transfected into the MSCs. The secretion of CGRP in culture supernatants of the transfected MSCs was detected using ELISA method. The cells at passage 3 were divided into three groups: CGRP group (MSCs transfected with Lenti-CGRP), CGRP+CGRP8-37 (an antagonist of CGRP receptor) group and control group (MSCs transfected with PBS). The differentiation of the MSCs was detected by immunocytochemical staining for CD31 and factor Ⅷ-related antigen. The proliferation of the cells was measured by cell counting, and the angiogenic ability of the cells was analyzed using Matrigel assay. RESULTS：The proportion of CD31-and factor Ⅷ-related antigen-positive cells in CGRP and CGRP+CGRP8-37 groups was larger than that in control group (P<0.05). The numbers of the cells in CGRP and CGRP+CGRP8-37 groups were significantly increased compared with control group (P<0.05). Lumen-like structures were observed in CGRP and CGRP+CGRP8-37 groups. The above indexes in CGRP+CGRP8-37 group were reduced compared with CGRP group. CONCLUSION: Transfection with CGRP gene induces rat bone marrow MSCs to differentiate into endothelial cells and enhances their proliferation, suggesting that CGRP may play a role in the regulation of angiogenesis.     

Neural differentiation of bone marrow mesenchymal stem cells from an Alzheimer disease mouse model

AIM：To estimate the neural differentiation efficiency of bone marrow mesenchymal stem cells (MSCs) derived from amyloid precursor protein (APP) transgenic mice and to investigate the correlation with Notch1 signaling and the autophagy activity during the differentiation. METHODS：The MSCs were divided into APP group (MSCs from APP transgenic mice) and WT group (MSCs from wild-type mice). MSCs were treated with β-mercaptoethanol as an inducer for differentiating into neurons. The levels of Aβ40 and Aβ42 were measured using enzyme-linked immunosorbent assay kits. The expression of neural cell-specific markers, neuron-specific enolase (NSE) and microtubule-associated protein 2 (MAP-2), was measured by immunocytochemistry and Western blotting. The expression levels of Notch1, Notch intracellular domain (NICD), Hes5, LC3 and p62 (a selective substrate of autophagy) were also detected by Western blotting. RESULTS：The neural differentiation capacity and the Aβ expression level of the MSCs in APP group were higher than those in WT group, and stronger inhibition of Notch1 signaling pathway in the MSCs from APP group was observed. However, the process of autophagy, which is essential for the survival and function of the neural cells, was impaired in the neural differentiated counterpart of the MSCs in APP group. CONCLUSION:Over-expression of APP might contribute to the high neural differentiation capacity of MSCs by inhibiting Notch1 signaling pathway in vitro. However, autophagy is impaired in the differentiated MSCs from APP transgenic mice.     

Suppression of tumor growth by mRNA DC vaccine in severe combined immune deficiency mouse

AIM: To establish HCC Hu-PBL-SCID(severe combined immune deficiency) chimeric model,and to observe the antitumor effect of mRNA-dendritic cell vaccine.METHODS: Hu-PBL-SCID chimeric model was established by intraperitoneal injection of human peripheral blood lymphocytes.Human IgG in mouse serum was detected by ELISA to identify the model.After the model was established,the mice were divided into four groups,and were inoculated with mRNA DC vaccine,anti CD4+,CD8++mRNA DC,naive DC,and PBS,respectively.Then the animals were injected subcutaneously with 2×106 HepG-2 cells.Tumorigenecity,latent period,and tumor volume were observed,and antitumor efficacy of CTL was measured.RESULTS: The concentration of human IgG in mouse serum in Hu-PBL- SCID model was detected,indicating that the Hu-PBL-SCID model was established successfully.No significant difference of tumorigenecity among the four groups was observed.However,tumors in mRNA DC vaccine group grew slowly,tumor volumes were significantly smaller than those in anti CD⁴⁺,CD⁸⁺+mRNA DC,PBS and naive DC groups.The spleen cells in mRNA DC vaccine group specifically killed the HepG-2 cells but not SGC-7901 cells.CONCLUSION: mRNA DC vaccine shows anti-tumor immune response in vivo by inducing CD⁴⁺,CD⁸⁺T lymphocyte immune responses.     

Effect of lentiviral vector of microRNA-9-1 on differentiation of mouse bone marrow mesenchymal stem cells into neurons

AIM: To investigate the role of microRNA-9 in inducing bone marrow mesenchymal stem cell(MSCs) differentiation into neurons.METHODS: The lentiviral vector of microRNA-9-1(microRNA-9-1-LV) was constructed and transfected into mouse MSCs. The cells were divided into non-transfected group, transfected group(transfected with microRNA-9-1-LV) and negative control group(transfected with FU-RNAi-NC-LV). MSCs were treated with β-mercaptoethanol(β-ME) as an inducer for triggering the cells to differentiate into neurons. The fluorescence expressed by transfected MSCs were observed under inverted fluorescence microscope. The mRNA expression of microtublin-associated protein 2(MAP-2) was detected by RT-PCR. The expression of neuron-specific markers,neuron-specific enolase(NSE), MAP-2 and glial fibrillary acidic protein(GFAP), were measured by immunocytochemical method. The viability of MSCs was determined by MTT method. RESULTS: The results of PCR confirmed successful construction of mouse microRNA-9-1-LV. The virus titer was 1×10¹² TU/L(TU, transduction unit). The best transfection efficiency(up to 91.3%±4.2%) and survival rate appeared when multiply of infection(MOI)was 20 and on 4th day. β-ME induced MSCs to differentiate into neurons and the best efficiency of the induction was observed in transfected group. The expression levels of NSE and MAP-2 in transfected cells were higher than those in the cells of other group(P<0.05).CONCLUSION: MicroRNA-9-1-LV has high transfection efficiency in mouse MSCs. Higher differentiation rate from mouse MSCs to neurons is induced by β-ME after the cells are transfected with microRNA-9-1-LV.     

Regulatory T cells regulate function of effector T lymphocytes in tumor-draining lymph node of mouse hepatocelluar carcinoma

AIM: To investigate the roles of regulatory T cells (Tregs) on the function of effector T lymphocytes in tumor-draining lymph nodes (TDLNs). METHODS: The number expansion of Foxp3+ Tregs and CD4+ or CD8+ T cells in the TDLNs from mouse hepatocellular carcinoma model was detected by immunohistochemical staining and flow cytometry. Foxp3 mRNA expression was determined by real-time quantitative PCR. The ability of IFN-γ secretion in CD8+ T cells in the TDLNs was measured by enzyme-linked immunosorbent spot technique(ELISPOT). RESULTS: The expansions of Tregs and effector T cells were significantly increased in the TDLNs during tumor development. Tregs diffusely distributed in the CD8+ T cells occupancy area. The level of Foxp3 mRNA expression was significantly higher in the TDLNs than that in the inguinal lymph node (P<0.01) and spleen (P<0.01) from the same mouse inoculated Hepa1-6 cells. Tregs trended to accumulate within the TDLNs exclusively, but not in other peripheral lymph nodes(LNs) of the same host. Foxp3 mRNA expression was significantly higher in the spleen from the tumor mice than that from mice injected with LPS (P<0.01). Tregs suppressed the CD8+ T cells primed in the TDLNs that retained the ability to secrete IFN-γ via anti-CD3 stimulation. CONCLUSION: Tregs play an important role in regulating the function of CD8+ T cells. Deletion of Tregs could be crucial for establishment of tumor-specific immunotherapy.     

TMAO aggravates heart failure by promoting T-tubule remodeling in adult mouse cardiomyocytes

AIM To investigate the role of trimethylamine N-oxide （TMAO） in T-tubule in cultured adult mouse cardiomyocytes. METHODS T-tubule imaging was used to detect T-tubule network in cardiomyocytes. Ca²⁺ handling dysfunction was identified by confocal Ca²⁺ imaging. Tubulin densification and polymerization in the cardiomyocytes were assessed by Western blot and immunofluorescence staining. Echocardiography was used to detect cardiac function in the mice fed on TMAO and chow diet. RESULTS Compared with control group, the T-tubule density and T-tubule power of the mouse cardiomyocytes cultured with TMAO were significantly decreased (P<0.01). Compared with control group, the mean amplitude of Ca²⁺ transients in TMAO group was decreased (P<0.01), while the time to reach the Ca²⁺ transient peak and the dyssynchrony index increased (P<0.01). Compared with control group, the power of junctophilin-2 (JPH2） in the mouse cardiomyocytes treated with TMAO was decreased (P<0.01). Significant JPH2 accumulation was observed at the edge of the cardiomyocytes (P<0.01). Compared with control group, the microtubule density in TMAO group was significantly higher (P<0.01), and microtubule aggregation was enhanced (P<0.01). Compared with the mice in control group fed on a normal diet, the TMAO-fed mice had significantly lower systolic function and left ventricular ejection fraction (P<0.05). CONCLUSION TMAO impairs cardiac function via the promotion of tubulin polymerization, subsequent JPH2 translocation and T-tubule remodeling, which provides a novel mechanism for the relationship between heart failure and elevated TMAO.     

Effect of adoptive transfer of CD4+ T cells with miR-7 knockdown on acute liver injury in mice

AIM:To study the effect of adoptive transfer of CD4⁺ T cells with microRNA-7 (miR-7) knockdown (KD) on mouse acute liver injury model and to investigate its significance. METHODS:CD4⁺ CD62L⁺ T cells were purified from the spleen of normal wild-type (WT) mice and miR-7KD mice by magnetic bead sorting, and were stained with CFSE. These 2×10⁶ CFSE-labeling cells were injected into normal mice via tail vein, and then the mouse acute liver injury model was induced by intraperitoneal injection of 30 mg/kg concanavalin A. After 72 h, the appearance, weight and weight index of the liver were investigated. The pathological change of the liver tissues was observed by HE staining. Real-time PCR was used to examine the mRNA expression of Bax and P53. The expression levels of CD62L, interleukin-4 (IL-4) and interferon-γ (IFN-γ) in the CD4⁺ T cells were analyzed by flow cytometry. RESULTS:We found that the liver tissue became lighter, and the weight (P<0.01) and weight index (P<0.05) were changed significantly in miR-7KD mice compared with control group. Moreover, HE staining showed that the liver cell damage was increased in the liver of miR-7KD mice. Meanwhile, the expression levels of Bax and P53 were significantly increased in miR-7KD group (P<0.05). The percentage of CD62L in CD4⁺ T cells was significantly decreased (P<0.01) in miR-7KD mice, with high expression of IFN-γ (P<0.05) and low expression of IL-4 (P<0.01) in CD4⁺T cells. CONCLUSION:These findings suggest that miR-7 knockdown significantly promotes the pathology of CD4⁺ T cell-mediated acute liver injury, which provides a preliminary experimental basis for further exploration on the mechanism of acute liver injury occurrence.     

Intracellular Ca2+ mobilization in mouse CD8+ T- lymphocytes immunized with gp96-peptide complexes

AIM: To further investigate the effect and mechanism of gp96-peptide complexes by observing ［Ca2+］i mobilization in CD8+ T-lymphocytes. METHODS: Spleen T-lymphocytes from the mice immunized with gp96-peptide complexes were used. The cell was stained with quantum-red-labeled anti-CD8 mAb and loaded with Fluo-3/AM. The double-color flow cytometry analysis method was used to detect ［Ca2+］i changes in CD8+ T-lymphocytes from the mice immunized with gp96-peptide complexes. A23187, MnCl2 and Con A were used as stimulators. RESULTS: The ［Ca2+］i in immunized CD8+T-lymphocytes was higher than that in non-immunized cells. Compared with the control group, A23187 and Con A induced higher ［Ca2+］i increases in spleen CD8+ T-lymphocytes of gp96-peptide complexes-stimulated mice than that in non-immunized cells. CONCLUSION: CD8+T-lymphocytes activation is likely due to an elevation of ［Ca2+］i. It suggests that gp96-peptide complexes play a significant role in the modulation of CD8+ T-lymphocytes responses.     

Effects of glucocorticoid on miRNA-155 expression in CD4+T cells of asthmatic mice

AIM:To investigate the effects of glucocorticoid on the regulation of microRNA-155 (miRNA-155) expression in the CD4⁺ T cells of asthmatic mice. METHODS:The ovalbumin (OVA)-induced asthma mouse model was established and the mice were treated with glucocorticoid. The effects of glucocorticoid on the pulmpnary histopathological changes, the expression of miRNA-155 in the lung tissues and CD4⁺T cells, and the levels of cytokines in the bronchoal-veolar lavage fluid (BALF) were evaluated. RESULTS:The results of RT-qPCR showed that the expressions of miRNA-155 in the lung tissues and CD4⁺T cells from the spleen of asthmatic mice were significantly increased, and the level of miRNA-155 in the CD4⁺T cells was significantly increased with the increase in the allergen exposure time (P<0.01). HE and PAS staining showed that OVA significantly increased inflammatory cell infiltration as compared with control group, and the peribronchial and perivascular inflammation and mucus secretion of proliferative goblet cells were significantly reduced after glucocorticoid treatment. Glucocorticoid treatment inhibited the increase in the proportion of CD4⁺ CD8^- cells in the spleen and decreased the accumulation of CD4⁺ T cells in the lung tissues of asthmatic mice (P<0.01). After glucocorticoid treatment, the levels of interleukin-4 (IL-4), IL-5 and IL-13 in BALF were decreased, while the level of interferon-γ was increased significantly (P<0.01). CONCLUSION:Glucocorticoid reduces the accumulation of CD4⁺ T cells and inhibits the expression of miRNA-155 in the lung tissues and spleen CD4⁺ T cells of asthmatic mice.     

Treatment of Con A-induced autoimmune hepatitis with hepatic artery transplantation of allogeneic ADSCs in mice

AIM: To explore the therapeutic potential of adipose tissue-derived stem cell (ADSC) transplantation via hepatic artery in concanavalin A(Con A)-induced autoimmune hepatitis in mice. METHODS: Forty mice with Con A-induced hepatitis were randomly divided into 4 groups: negative group, hepatic artery group, caudal vein,group and positive control group. The mice in hepatic artery group and caudal group were transplanted with ADSCs (2×10⁶) via hepatic artery and caudal vein, respectively. Cyclophosphamide injection was taken as positive control. Inflammatory cytokines involved in Con A-induced hepatitis, liver function index, manifestations and pathological changes of the liver were observed before and after treatment. RESULTS: All animals survived after ADSC transplantation in hepatic artery group and caudal vein group. Compared with caudal vein transplantation group, ADSC transplantation via hepatic artery significantly reduced the release of inflammatory cytokines (IFN-γ,IL-4 and IL-5), and the serum levels of aspartate aminotransferase, alanine aminotransferase and alkaline phosphatase. Pathological changes of the livers showed that the extent of inflammatory infiltration after hepatic artery transplantation of ADSCs was similar to that in positive control group. The inflammatory cells and necrosis of hepatic cells were significantly reduced compared with those in caudal vein group. CONCLUSION: Transplantation of allogeneic ADSCs via hepatic artery attenuates Con A-induced autoimmune hepatitis in mice. ADSC transplantation may be the potential therapy for autoimmune hepatitis.     

Biological characteristics of bone marrow mesenchymal stem cells from GFP transgenic mice transfected with human β-nerve growth factor gene

AIM:To investigate the changes of biological characteristics of GFP transgenic mouse bone marrow mesenchymal stem cells (MSCs), which were transfected with human β-nerve growth factor (β-NGF) gene in a recombinant eukaryotic expression vector. METHODS:MSCs obtained from GFP transgenic mice were isolated, cultured and purified by the whole bone marrow adherence methods. Human β-NGF gene was transfected into the MSCs by a recombinant eukaryotic expression vector. The β-NGF expression in the MSCs was detected by the method of immunocytochemistry. Hippocampal neurons from neonatal mice were cultured with culture supernatant of the MSCs transfected with pcDNA3-β-NGF and the biological characteristics of the MSCs were investigated 3 d after culture under inverted phase-contrast microscope. RESULTS:The β-NGF positive rate of MSCs in pcDNA3-β-NGF transfection group ［(37.12±2.14)%］ was significantly higher than that in MSCs control group ［(2.36±0.62)%］ and blank control group ［(1.43±0.76)%］.The neurite length of neonatal mouse hippocampal neurons cultured with culture supernatant from pcDNA3-β-NGF-transfected MSCs ［(31±3)μm］ was significantly longer than that in negative control group ［(23±4)μm］, suggesting that MSCs transfected with β-NGF gene maintained better biological characteristics. CONCLUSION: The constructed recombinant eukaryotic expression vector of human β-NGF gene can be transfected into MSCs efficiently and NGF can be effectively expressed in MSCs. MSCs transfected with β-NGF gene are capable of stable expression and secretion of β-NGF, and maintenance of better biological characteristics.     

In vitro hematopoietic stem cells from embryonic stem cells reconstruct hematopoiesis in mice

AIM: To investigate the potential of hematopoietic stem cells (HSCs) derived from mouse embryonic stem cells (ESCs) to reconstruct hematopoiesis in vivo. METHODS: Using a three-step method, a mice embryonic stem cell line, E14.1 was induced into hematopoietic stem cells. The cell markers with CD34+/ Sca-1+ were identified by flow cytometry analysis, then HSCs (1×109 cells/L) from third-step were injected into SCID mice for observing teratoma formation. To validate function of HSCs, colonogenic cell assay was conducted and the hematopoiesis in lethally irradiated mice was reconstituted. RESULTS: The method of three-step differentiation, combined to use more hematopoietic stimulating factor promoted the E14.1 cell differentiation into HSCs with highest percent of CD34+/Sca-1+ cells (as high as 58.64%±4.20%) with more CFU-E, CFU-GM and CFU-GEMM populations. The cells showed the character of hematopoietic progenitors by Wright-Giemsa staining. Positive selected CD34+/Sca-1+ cells by magnetic sorting from third-step differentiation were transplanted into 7 lethally irradiated female mice while predominant hematopoietic reconstitution were observed in 10 d after transplantation, with 71.4% (5/7) successful engraftment rate. Three recipients showed that the cell population of the peripheral blood leukocytes, red blood cells and hemoglobin approached to normal index at 40 d after transplantation, but followed relative slow renew in platelet count. Survival rate in transplant group was 43%, compared to 100% mortality in control mice. Karyotyping assays confirmed the female mice with XY. CONCLUSION: The three-step differentiation and the culture conditions described here support the differentiation of mouse ESCs into HSCs. HSCs derived from mouse ESCs can reconstruct hematopoiesis.     

Effect of bone marrow mesenchymal stem cells on engraftment of hematopoietic stem/progenitor cells in sensitized mice

AIM: To evaluate the effects of bone marrow-derived mesenchymal stem cells (MSCs) on engraftment of hematopoietic stem/progenitor cells in sensitized mice. METHODS: Mouse bone marrow-derived MSCs were cultured by adherent culture method. MSCs combined with or without hematopoietic stem/progenitor cells were implanted into the sensitized mouse model, which was established by allogeneic splenocyte transfusion, and were divided into 6 groups: MSC intervention groups, including sensitized mice with MSCs on day 11, sensitized mice with MSCs on day 0 and sensitized-mice with MSCs both on day 11 and day 0; control groups, including sensitized mice without MSC intervention, non-sensitized mice without MSC intervention and non-sensitized mice without MSCs or transplantation of hematopoietic stem/progenitor cells. The survivors were assessed after transplantation and hematopoietic recovery was monitored weekly including hematological change, immune function reconstruction, bone marrow cell recovery, chimera analysis and graft-versus-host disease development. RESULTS: Compared with different control groups, MSC intervention did not prolong the survival rates of the sensitized model mice after lethal irradiation. CONCLUSION: Under the experimental conditions, MSC combined with C57BL/6 bone marrow hematopoietic stem/progenitor cells fail to promote the growth of engraftment in C57BL/6 allogeneic splenocyte-sensitized BALB/c mice in vivo.