Mechanism of granulocyte colony-stimulating factor for promoting cell viability of bone marrow mesenchymal stem cells / 生理学报

The present study was aimed to investigate the mechanism of the granulocyte colony-stimulating factor (G-CSF) on the viability of the bone marrow mesenchymal stem cells (MSCs). MSCs were cultured by classical whole bone marrow adhering method, and the MSCs were analyzed for the cell surface differentiation markers CD34, CD133, CD90 and CD105 by flow cytometry (FCM). The ability of the MSCs to differentiate into osteocytes and adipocytes was tested in osteogenic and adipogenic mediums, separately. The effect of G-CSF (20 mug/mL) on the passage 3 MSCs viability was evaluated by MTT method, and the molecular mechanism of the G-CSF mediated effects was assayed through the pretreatment of the signal pathway inhibitors including 50 nmol/L wortmannin (phosphatidylinoesitol 3 kinase inhibitor), 50 mumol/L PD98059 [extracellular signal-regulated-kinase1/2 (ERK1/2) inhibitor], 30 mumol/L SB203580 (p38 mitogen-activated protein kinase inhibitor), 10 mumol/L H89 (protein kinase A inhibitor), 20 mumol/L Y27632 (Rho kinase inhibitor), 1 mumol/L rapamycin [mammalian target of rapamycin (mTOR) inhibitor], 10 mmol/L straurosporine [protein kinase C (PKC) inhibitor], 6 nmol/L G0697 (PKCalpha inhibitor) and 50 mumol/L Pseudo Z (PKCzeta inhibitor). Cultured passage 3 MSCs expressed CD90 and CD105 strongly, and showed the ability of multi-differentiation into osteocytes and adipocytes. G-CSF promoted the viability of MSCs, and the promotion was completely inhibited by PKC inhibitor straurosporine and partially inhibited by wortmannin, rapamycin, PD98059, SB203580 or G0697. However, its effect was not inhibited by H89, Y27632 and Pseudo Z. It is thus suggested that the promoting effect of G-CSF on MSCs viability was closely related to AKT-mTOR-PKC signal pathway, and PKC maybe the central role in the signal pathway.

Effects of different doses of thrombopoietin on proliferation of bone marrow mesenchymal stem cells in mice / 中国实验血液学杂志

To explore the effect of different doses of thrombopoietin on proliferation of bone marrow mesenchymal stem cells (MSCs) in mice, 20 Kunming mice (35 +/- 5 g) were divided randomly into 4 groups: low-dose TPO group, moderate-dose TPO group, high-dose TPO group and normal control group (n = 5). The experimental groups were subjected to intraperitoneal injections of TPO at a dose of 25, 50, 100 microg/kg, respectively, and normal control group were treated with saline at a dose of 0.1 ml/g per day for 5 days. The bone marrow was harvested on 12 hours after the final administration. The bone marrow nucleated cells (BMNCs) were counted and seeded at a density of 10(6) cells/cm(2). The colony-forming unit-fibroblast (CFU-F) of MSCs was cultured and evaluated. The CFU-F of MSCs underwent osteo-genic induction and adipogenic induction, and cytochemical and immunocytochemical staining were performed to verify their multipotential. CFU-F and the cell percentage of CD90(+), CD105(+), CD34(+) in BMNCs were analyzed by flow cytometry. The results showed that the number of BMNCs and the cell percentage of CD90(+), CD105(+), CD34(+) and CFU-F increased obviously in TPO groups as compared with the normal control group (p < 0.05). The number of BMNCs increased most obviously in the 50 microg/kg TPO group. However, there was no significant difference in number of CFU-F between 50 microg/kg and 100 microg/kg TPO group (p > 0.05). The CFU-F of MSCs in bone marrow had their osteogenic and adipogenic differentiation potentials in vitro. It is concluded that the number of BMNCs and the cell percentage of CD90(+), CD105(+) and CFU-F increased after administration with TPO. It means that TPO can enhance MSCs to proliferate in bone marrow. However, the number of BMNCs and CFU-F can not increase with the increase of TPO dose.

Erythropoietin promotes proliferation of human bone marrow mesenchymal stem cells in vitro / 中国实验血液学杂志

This study was aimed to investigate the effects of recombinant human erythropoietin (rhEPO) on proliferation of human bone marrow-derived mesenchymal stem cells (MSCs) in vitro. The aspirates of the bone marrow from healty volunteers were seeded in culture medium. Then MSCs were isolated according to characteristics adhering to the plastics. After three passages in culture, bone marrow-derived adherent cells were identified by growing morphological features, cell surface antigens and differentiation into multi-lineages. Then P3-MSCs which had been identified were incubated with different concentrations of rhEPO (0.5, 1, 5, 10 and 50 U/ml). Subsequently, proliferation of MSCs was measured by MTT assay, as well as cell counts. At the same time, cell cycle was detected by flow cytometry (FCM). The results indicated that the expressions of CD90 and CD105 in P3 bone marrow-derived adherent cells were positive, while the expressions of CD34 and CD45 were negative, and these cells could differentiate into adipocytes, osteocytes and chondrocytes in induction media. MTT assay showed that the optical density (OD) of group treated with EPO was significantly higher than that in the control group (p<0.05), and the group treated with 50 U/ml EPO achieved the most predominant effects. The results of cell count were coincident with that of MTT assay. Furthermore, the cell cycle analysis by FCM revealed that rhEPO could relatively decrease the cell ratio in G0/G1 phase, and increase the cell ratio in S and G2/M phases. As compared with the control group, all those differences were statistically significant (p<0.01). It is concluded that erythropoietin can promote proliferation of human bone marrow mesenchymal stem cells in vitro, which may be correlated with the increased entry into S and M phases of cell cycle of MSCs adjusted by EPO.

Effects of rhG-CSF on mobilization of mouse mesenchymal stem cells / 中国实验血液学杂志

To evaluate the effects of rhG-CSF on mobilization of mesenchymal stem cells (MSCs) of mouse bone marrow at different time point, thirty mice were randomly divided into rhG-CSF treatment group and control group. The mice were subcutaneously injected with rhG-CSF in a dose of 80 microg/kg or saline for 5 days. The bone marrow and peripheral blood were obtained at time points of 6, 12, 168 hours after final injection of rhG-CSF or saline. Bone marrow mononuclear cells (BMMNCs) were seeded at density of 1 x 10(6) MNCs onto 12-well plate for culture expansion in DMEM supplemented with 10% FBS, and the number of colony forming unit - fibroblast (CFU-F) was counted after 14 days. The cells were collected by trypsinization and the surface antigens CD34, CD133, CD90 and CD105 were analyzed by flow cytometry. The multi-differentiation of MSCs were done in the culture condition of induced-adipocyte and osteocyte. Peripheral blood MNCs examination was same as the bone marrow. The results indicated that the number of CFU-F of bone marrow in rhG-CSF group was more than that in control group (p < 0.01), the number of CFU-F in rhG-CSF group at 6 hours was more than that at 12 hours and 168 hours, respectively (p < 0.01). There was no obvious difference between CFU-F at 12 hours and at 168 hours (p > 0.05). MSCs were positive for CD90, CD105 and negative for CD34 and CD133. MSCs were found to differentiate into adipocyte and osteocyte in vitro. The CFU-F of PBMNCs obtained and cultured in vitro in the same culture conditions could be observed after the rhG-CSF injection at 6 hours, but cloning efficiency was (0.50 +/- 0.11) x 10(-6) MNCs and showed statistical difference as compared with control. It is concluded that rhG-CSF to mobilize hemopoietic stem cells can be used to induce mouse MSCs in vivo expansion, which showed the peak value within 6 hours after final injection of rhG-CSF. rhG-CSF have the mini-mobilization effect on murine MSCs derived from bone marrow.