To investigate the possible involvement of Ras signaling in the hematopoietic differentiation of embryonic stem cells (ES cells), ES cells were transfected with RasN17, the dominant-negative mutant of Ras. Western blot was used to test the effect of RasN17 expression on Erk1/2 and Akt phosphorylation, semi-quantitative RT-PCR was used to detect expression of gene related to hematopoiesis in differentiation of ES cells. The results showed that the expression of RasN17 in the ES cells remarkably downregulated the phosphorylation of Erk1/2 and Akt simultaneously. Moreover, the expression of several markers related with hematopoiesis including Runx1, SCL and beta-major globin, were significantly suppressed in the EB expressing RasN17, whereas the transcription of Flk1, a gene required earlier than SCL in development of hematopoietic and endothelial lineages, was not influenced. It is concluded that the activation of Ras is pivotal for in vitro hematopoietic differentiation of ES cells.

To study the regulation of TGF-beta(1) on the development of hemangioblast, embryonic stem cell-derived blast forming cells (BL-CFC) were used as the model of hemangioblast in vitro. TGF-beta(1) or anti-TGF-beta(1) neutralization antibody was added in the medium of embryoid body (EB) generation for observating influence of TGF-B(1) addition in different culture stages on number of BL-CFC and differentiation of BL-CFC to endothelial and hematopoietic cells. The results showed that antagonizing TGF-beta(1) in the course of EB growth could significantly reduce the number of BL-CFC (P<0.01), and the frequency of Flk-1(+) cells was also decreased consistently. Furthermore, the BL-CFC derived from EB pretreated with TGF-beta(1) demonstrated remarkably elevated hematopoietic and endothelial potential, whereas such bi-potential was impaired in the group with neutralizing antibody. It is concluded that TGF-beta(1), a conventional negative regulator in hematopoiesis and angiogenesis exert positive effects on the development and differentiation capacities of BL-CFC in vitro.

The aim of this study was to investigate the effects of human fetal bone marrow stromal cells (FBMSC) in combination with exogenous cytokines on supporting in vitro expansion of CD133(+) cells in cord blood mononuclear cells (MNC). MNCs separated from cord blood (CB) were cultured for up to 14 days in a serum-free system with FBMSC or exogenous cytokines or both of them. On day 0, 6, 10 and 14, total nucleated cells (TNC) were counted; CD133(+) cells were quantified by FACS, and hematopoietic progenitor cells were assessed by semisolid culture assay. The results showed that the number of TNC was remarkably increased in FBMSC and cytokine group, the expansion of CD133(+) cells and CFU were increased in FBMSC and cytokine group except that on day 14. It is concluded that FBMSC play an important role in delaying the differentiation of hematopoietic cells. FBMSC in combination with exogenous cytokines can promote the effective expansion of CB MNC and CD133(+) cells, this expanding system may meet the needs for clinical application of expanded CD133(+) cells.

To investigate the effect of irradiation on the quantity and osteogenesis potential of BMMSCs and to explore the response of them in the irradiation stress and its contribution to long-term effects of radiation-induced bone and hematologic injury, a total body irradiation (TBI) murine model was adopted. The number of CFU-F and cell cycle profile of BMMSCs were analyzed at different time points before and after TBI. Osteogenic differentiation was evaluated by Von Kossa staining, expressions of osteogenesis-related genes and transcriptional coactivator with PDZ-binding motif (TAZ) were detected by real-time RT-PCR. The results showed that the number of CFU-F decreased greatly at day 28 after TBI. At day 3 after TBI, more cells entered cell cycle and the osteogenesis potential was greatly enhanced followed by recovery of cell cycle distribution and significant defect in osteoblast differentiation respectively, meanwhile the expression of TAZ was changed. It is concluded that TBI results in the reduction of bone marrow mesenchymal stem/progenitor cell pool and alters the osteogenesis potential of BMMSCs, which is related to the change of TAZ expression.

Duchenne muscular dystrophy (DMD) is a common X-linked disease characterized by widespread muscle damage that invariably leads to paralysis and death. There is currently no therapy for this disease. This study was purposed to investigate the feasibility to use adult adipose-derived mesenchymal stem cells (AD-MSCs) in the therapy of DMD. The Flk-1(+) MSCs were isolated from adipose tissue of adult GFP mice; the phenotype and cell cycle of MSCs were analyzed by flow cytometry; the AD-MSCs were directionally differentiated by myoblast and endotheliablast induction system in vitro and were identified by immumofluorecence staining and RT-PCR; the AD-MSCs were transplanted into CTX-injured mice model or mdx mice (DMD animal model) through tail vein; the distribution and differentiation of AD-MSCs were detected by immunofluorescence staining and RT-PCR respectively, and statistic analysis was performed. The results showed that the Flk-1(+) AD-MSCs could be induced to differentiate into myoblasts and endothelial cells in vitro. After transplanted into CTX-injured mice model or mdx mice, GFP-positive cells could be detected in damaged muscle, and these donor-derived cells were also positive for MHC, vWF, or Pax7. Flk-1(+) AD-MSC transplantation also partly reconstituted the expression of dystrophin, and reduced the percentage of centronucleated myofibers in mdx mice. It is concluded that Flk-1(+) AD-MSCs represent a possible tool for future cell therapy applications in DMD disease, as they can be delivered through the circulation for their potential of muscle homing. And Flk-1(+) AD-MSCs also show the ability to contribute to muscle repair, improvement of blood supply and long term reconstitution of dystrophy muscle.

This study was aimed to evaluate whether mesenchymal stem cells (MSCs) obtained from patients with myelodysplastic syndrome possess immunosuppressive effect. MSCs from bone marrow samples of MDS patients were isolated, cultured and expanded. MSCs were morphologically analyzed and their immunophenotype were determined by flow cytometry. Various amounts of MSCs were added into one-way mixed lymphocyte reaction. MSCs from MDS patients were tested for their ability to suppress in vitro proliferation of autologous and allogeneic peripheral blood lymphocytes (PBLs). The results showed that 3 x 10(3 - 1) x 10(5) MSCs from MDS patients could inhibit autologuous PBLs proliferation to (66.9 +/- 20.1)% - (30.2 +/- 5.9)% of maximal response, as well as inhibit allogeneic PBLs proliferation to (56.6 +/- 14.7)% - (20.5% +/- 9.7)% of maximal response, as compared with inhibitory ability of MSCs from healthy donors, there was no significant difference (P>0.05). It is concluded MSCs from patients with myelodysplastic syndrome also possess immunosuppressive activity.

This study was aimed to investigate the expression and regulation mechanism of DNA-dependent protein kinase catalylic subunit (DNA-PKcs) in chronic myeloid leukemia (CML) and its role in blast crisis of CML. Expression of DNA-PKcs mRNA was detected by semi-quantitative reverse transcription polymerase chain reaction (RT-PCR) and DNA-PKcs protein by Western blot in 62 CML patients and K562, as compared to those of 23 normal individual controls. In 26 CML patients received allogeneic peripheral blood stem cell transplantation (allo-PBSCT) and 4 CML patients treated with imatinib, the expression of bcr-abl mRNA and DNA-PKcs protein was detected by RT-PCR and Western blot, respectively. After treatment with imatinib in mononuclear cell (MNC) of CML patients and K562 in vitro, expression of DNA-PKcs mRNA was detected by RT-PCR and DNA-PKcs protein level, tyrosine phosphorylation of bcr-abl fusion protein were detected by Western blot. The results showed that the expression of DNA-PKcs protein was significantly lower in CML and K562 than those in normal control (P<0.05). In 26 CML patients received allo-PBSCT and 4 CML patients treated with imatinib, the expression of DNA-PKcs protein was enhanced while the expression of bcr-abl mRNA decreased. After treatment of MNC of CML and K562 with imatinib in vitro, the expression of DNA-PKcs protein was enhanced while tyrosine phosphorylation of bcr-abl fusion protein decreased. It is concluded that the expression of DNA-PKcs protein is down-regulate by bcr-abl fusion gene, and the bcr-abl fusion gene down-regulate the expression of DNA-PKcs protein by post-transcriptional mechanism; the decrease of DNA-PKcs protein expression may be one of mechanisms underlying the acute transformation of CML.

This study was purposed to investigate the sensitivity and specificity of conventional cytogenetics (CC), nested-reverse transcriptase polymerase chain reaction (nested-RT-PCR) and dual-color/dual-fusion fluorescence in situ hybridization (D-FISH) technique in monitoring the tumor load of chronic myeloid leukemia (CML) during treatment with transplantation. CC, nested-RT-PCR and interphase D-FISH were simultaneously carried out to detect the tumor load of 7 CML patients during treatment with non-myeloablative allogeneic stem cell transplantation (allo-NSCT). 40 specimens from 7 CML patients before and after allo-NSCT were analyzed. The results showed that 29 specimens were Ph (+) with different positive ratio and 3 specimens with lower cells were not analyzed by CC. 36 specimens were bcr/abl mRNA (+) by RT-PCR. 4 specimens from case 1 at 12, 18, 26 and 38 months after allo-NSCT were Ph (-) and bcr/abl mRNA (-), 4 Ph (-) bcr/abl (+) specimens containing 2 from case 1 at 9 and 10 months after allo-NSCT, 1 from case 2 at 15 months after allo-NSCT, 1 from case 3 at 12 months after allo-NSCT showed 5.4%, 0%, 16.5% and 1.5% bcr/abl (+) cells by FISH. 3 specimens with lower cells containing 2 from case 5 at 20 and 60 days after allo-NSCT and 1 from case 7 at 40 days after allo-NSCT were analyzed by FISH and showed 55.0%, 27.5% and 73.5% bcr/abl (+) cells. The Ph (-) bcr/abl (-) specimen from case 1 at 12 months post-allo-NSCT showed 0% bcr/abl (+) cells by FISH. It is concluded that CC can be used as a basic tool to monitor the change of tumor load in CML during treatment. When specimen with lower cells can not be analyzed by CC in early period after allo-NSCT, or result of CC can not evaluate precisely dynamic change of tumor load and when tumor load in treated patient are lower to Ph (-) by CC while bcr/abl mRNA (+) by RT-PCR, FISH must be used to detect precisely tumor load and monitor dynamic change of it. More sensitive RT-PCR is used to monitor tumor load when it is lower to bcr/abl (-) by FISH during treatment.

To determine whether the surviving mesenchymal stem cells (MSCs) in the testis after transplantation can differentiate into quasi-sperm.

Developmental programs of blood and endothelium are closely correlated and remarkably conserved among species. To categorize the ontogeny relationship between hematopoietic and endothelial lineages, two putative models are presented here. In the yolk sac, hematopoietic and endothelial cells are more likely derived from a common precursor--the hemangioblast. By comparison, the hemogenic endothelium is proposed to characterize the generation of hematopoietic stem cells from mature endothelium in the P-Sp/AGM region. Furthermore, couples of molecules, including Scl, Flk-1 and Runx-1, are involved in formation and subsequent differentiation of the hemangioblast or hemogenic endothelium during embryonic hematopoiesis. In this article, the development of primitive and definitive hematopoiesis, two models associated with development of hematopoietic and vascular endothelial cells as well as molecules associated with development of hematopoietic and endotheliate cells were summaried.

This study was purposed to investigate the immunoregulatory effect of endothelial cells derived from mesenchymal stem cells (MSC). The human MSC was induced to differentiate into endothelial cells for one week. The phenotypes were evaluated by flow cytometry, the cell morphologic feature was observed by invert phase-contrast microscope and analysis of capillary formation was performed by using the in vitro angiogenesis kit. The immunoregulatory effect was detected by lymphocyte transformation test. The result indicated that during the differentiation cells grew fast and there was no significant change in the phenotypes, i.e. CD73, CD105, HLA-ABC were positive and CD34, CD80, CD86, HLA-DR, CD31 were negative. Immunofluorescence analysis showed typical expression of the von Willebrand factor. Differentiated MSCs formed capillary-like structure. Endothelial cells derived from MSC also revealed immunosuppressive effect on T cell proliferation in a dose-dependent manner. It is concluded that endothelial cells derived from MSC also harbor immunoregulatory effect on T lymphocytes.

The aim of study was to select the best scheme of G-CSF to mobilize peripheral stem/progenitor cells in healthy donors. The clinical data of 60 cases received nonmyeloablative allogenic hematopoietic stem cell transplantation was analyzed retrospectively. The results indicated that the counts of MNC and CD34(+) cells were significantly higher in the 10 microg/(kg.d) group than that in the 5 microg/(kg.d) group (P < 0.05). The counts of MNC and CD34(+) cells which were collected after day 4 or 5 in the 10 microg/(kg.d) groups were not significantly different. The percentage of CD3(+) cells, CD4(+) cells and CD8(+) cells were not different in different groups. It is concluded that the scheme using 10 microg/(kg.d) G-CSF is more efficient than that in the 5 microg/(kg.d) group in mobilizing stem cells. It may reduce days for mobilization and decrease expense for collection of cells after 4 days of mobilization. Scheme using 10 microg/(kg.d) G-CSF for cells collecting after 4 days is more efficient.

The study was purposed to explore the effects of NKG2D receptor and its ligands RAE-1 and H60 on graft-versus-tumor (GVT) response induced by MHC haploidentical bone marrow/spleen cell transplantation. Female (BALB/c x C57BL/6) F1 mice (CB6F1, H-2K(b/d)) inoculated with H22 cells to develop a solid tumor model were the recipients, and bone marrow mixed with spleen cells of the healthy male C57BL/6 (H-2K(b)) mice were the donor cells. GVT response was observed after transplantation that from donor cells T and NK cells were purged with anti-CD3 and anti-NK monoclonal antibody, and the NKG2D receptor was blocked with anti-NKG2D monoclonal antibody, the expression levels of RAE-1 and H60 mRNA in tumor tissue were measured by means of semi-quantitative reverse transcription polymerase chain reaction (RT-PCR) at different time points after transplantation. The results showed that the GVT response of transplantation was reduced after in vitro depletion of T and NK cells or blocking NKG2D receptor in donor cells of the graft, the expression levels of RAE-1 and H60 mRNA in tumor tissue increased after transplantation of haploidential bone marrow mixed with spleen cells. It is concluded that NKG2D and its ligands RAE-1 and H60 may play important roles in GVT response.

The study was purposed to analyze the relationship between the content of T-cell receptor excision DNA circles (TREC) and bcr-abl mRNA levels in CML patients and to evaluate the prognostic significance of recent thymic output function detection in patients with chronic myelogenous leukemia (CML). Quantitative detection of TREC and bcr-abl fusion gene transcripts in peripheral blood from 15 CML patients were preformed by real-time PCR. The change of bcr-abl levels in 6 patients was followed-up for two years. The results showed that there was no significant correlation between TREC and bcr-abl mRNA levels in peripheral blood from CML patients for the first attack. Patients who had higher TREC at diagnosis had a larger reduction of bcr-abl after 2 years of follow-up. While out of 2 patients who underwent haemopoietic stem cell transplantation (HSCT), one patient with higher level of TREC before transplantation was confirmed to express undetectable level of TREC by three consecutive detections after transplantation, other one patient was identified to express low level of bcr-abl. It is concluded that high thymic output function in CML patients can be beneficial for killing the residual CML cells.

The study was purposed to investigate the proliferation and the suppression effect of human cytomegalovirus (hCMV) on human promyelocyte cell line HL-60, and to study whether hCMV can induce apoptosis of HL-60 via direct infection in vitro and its mechanism. Promyelocyte cell line HL-60 and hCMV AD169 strain were co-cultured. PCR was used to detect the direct infection of HL-60 cells by hCMV IEA expression. The apoptosis cells were analyzed by morphologic observation, DNA ladder formation, flow cytometry with Annexin V/PI stain. The results indicated that hCMV AD169 suppressed the differentiation and proliferation of HL-60 cells in vitro significantly (P < 0.05). The suppression was dose-dependent. hCMV DNA was successfully detected in HL-60 cells of viral infection groups by PCR. The apoptotic cells were confirmed by morphologic observation and DNA ladder formation. The results of flow cytometry showed that the percentage of apoptotic cells increased along with the increase of hCMV titer and the time after infection. It is concluded that the promyelocyte can be infected directly by hCMV AD169 strain. hCMV AD169 strain inhibited the differentiation and proliferation of promyelocyte. The apoptosis of HL-60 cells can be induced by hCMV infection. With the increase of viral infectious titer and the time after infection, the percentage of apoptotic cells also increase and produce in dose-dependent and time- dependent manner. Induced apoptosis may be one of the mechanisms of granulocytopenia induced by hCMV infection.

To investigate the more effective methods of isolation, culture of mesenchymal stem cell (MSC), and examine the surface phenotype of MSC. MSC were separated from rats bone marrow by plastic adherence methods and purified by controlling the time of digestion combined with adhesion separation, and proliferated in culture flasks that were coated with I collogen.

To find a method for isolation and cultivation of human adipose-derived mesenchymal stem cells(ADSCs), and to investigate its chondrogenic ability.

To study the effect of human bone marrow derived mesenchymal stem cell (MSC) on T cell cycle and activation, and to investigate the inhibitory effect of MSC on T cell proliferation and the underlying mechanism.

To observe the effects of endothelial cells from umbilical cord blood (UCB) on the amplification of human early hematopoietic cells from UCB in vitro.

To explore the ability of QY1 bone marrow mesenchymal stem cell (MSCs) line cells to differentiate into adipocytes, chondrocytes, osteoblasts, cardiac myocytes,vascular endothelial cells, and neural cells in vitro.