Thrombopoietin Prevents CoCl-inducing Apoptosis of HUVEC through the PI3K/AKT Pathway / 中国实验血液学杂志

<p><b>OBJECTIVE</b>To investigate the effect of thrombopoietin (TPO) on chemical hypoxia-induced apoptosis of human umbilical vein endothelial cells (HUVEC), and to explore its potential mechanism.</p><p><b>METHODS</b>The experiment was divided into 4 groups. The untreated HUVECs were used as normal control group. HUVECs treated with CoCl was CoCl group, and TPO was added into the culture medium 48 h before CoCl treatment as TPO + CoCl group. The cells was treated with TPO alone as TPO group. The cell viability and apoptosis of each groups were tested by Cell Counter Kit 8 (CCK-8) assay and flow cytometry. The expression of Caspase-3 and mitochondrial membrane potential (MMP) were then determined by flow cytometry with Caspase-3-PE and JC-1. The effect of TPO in PI3K/AKT pathway was detected by using Western blot.</p><p><b>RESULTS</b>CoCl significantly inhibited the growth of HUVECs. The cell viability of HUVECs decreased gradually with enhancement of CoCl at a gradient of chemical concentrations (r= -0.997). CoCl dramatically increased apoptosis of HUVECs, whereas pre-treatment with TPO rescued cell apoptosis induced by CoCl (P<0.001). Further investigation found that TPO decreased the expression of Caspase-3 and inhibited the reduction of MMP induced by CoCl (P<0.05). TPO could increased the activation of PI3K/AKT pathway in HUVECs.</p><p><b>CONCLUSION</b>TPO has a protective effect against CoCl-induced apoptosis of HUVECs through activating the PI3K/AKT pathway, thus decreasing the expression of apoptosis protease Caspase-3 and inhibiting the reduction of MMP.</p>

PDGF-BB Promotes CFU-GM and CFU-MK Formation and Its Possible Mechnism / 中国实验血液学杂志

<p><b>OBJECTIVE</b>To investigate the effect of platelet-derived growth factor (PDGF-BB) on the formation of granulocyte-monocyte colony forming unit (CFU-GM) and megakaryocyte colony forming unit (CFU-MK) and its anti-apoptotic effect on CHRF cells.</p><p><b>METHODS</b>The CFU-GM and CFU-MK of murine and human bone marrow cells were cultured in vitro by using plasma clot culture system. The anti-apoptotic effect of PDGF-BB on CHRF cells and its mechanism were clarified by flow cytometry.</p><p><b>RESULTS</b>PDGF-BB 0-100 ng/ml stimulated the proliferation of murine and human CFU-GM and CFU-MK in a dose-dependent manner. The maximal stimulation effect was obtained at 50 ng/ml of PDGF-BB (P<0.01). Furthermore, PDGF-BB had an anti-apoptotic effect on CHRF cells as shown by the flow cytometry with AnnexinV/PI double staining, Caspase-3 expression and JC-1 detection (P<0.05).</p><p><b>CONCLUSION</b>PDGF-BB significantly stimulates the proliferation of CFU-GM and CFU-MK in vitro, and has an anti-apoptotic effect on CHRF cells.</p>

Role of PDGF/PDGFR Pathway in Essential Thrombocythemia and Its Action Mechanism / 中国实验血液学杂志

<p><b>OBJECTIVE</b>To study the role of PDGF/PDGFR in essential thrombocythemia (ET) by investigating the expression of PDGF-BB in bone marrow and the expression of PDGFR-β in bone marrow cells of patients with ET and explore the new target for treating ET patients through inhibiting the PDGFR of megakaryocytes.</p><p><b>METHODS</b>The expression level of PDGF-BB in bone marrow of ET patients and normal controls were assayed by using ELISA, the expression level of PDGFR-β (CD140) in bone marrow of ET patients and normal controls were detected by using flow cytometry, the effect of PDGF-BB in JAK2/STAT3 and PI3K/AKT pathway was detected by using flow cytometry or Werstern blot, and the effect of imatinib on the megakaryopoiesis of PDGF was observed.</p><p><b>RESULTS</b>The expression level of PDGF-BB in bone marrow of ET patients was significantly higher than that in normal controls; the expression level of PDGFR-β in bone marrow of ET patients was significantly higher than that in nornal controls; PDGF-BB could activate JAK2/STAT3 and PI3K/AKT pathway of megakaryocytes, while the imatinib could block the effect of PDGF-BB on megakaryocyte.</p><p><b>CONCLUSION</b>The elevated PDGF-BB and PDGFR-β may be involved in ET, and the physiopathologic mechanism is that the elevated PDGF-BB activates PDGFR with subsequent activation of the JAK2/STAT3 and PI3K/AKT pathways, stimulating megakaryopoiesis. Imatinib may have a therapeutical effect on ET via blocking of PDGFR.</p>

Anti-apoptotic effect of Astragalus Polysaccharide on myeloid cells / 中国实验血液学杂志

This study was aimed to assess the effect of Astragalus Polysaccharide (ASPS) on in-vitro hematopoiesis. CFU-GM assays were used to determine the effect of ASPS and thrombopoietin (TPO) on granulocytic-monocyte progenitor cells. The CFU assays were also used to investigate the effect of ASPS on the proliferation of HL-60 cells.HL-60 cells were cultured with serum-free RPMI 1640 medium and treated with or without of different concentrations of ASPS. After 72 h incubation, the number of cells were counted.In addition, the caspase-3 and JC-1 expression was determined by flow cytometry with Annexin V/PI double staining. The results showed that ASPS (100, 200 µg/ml) and TPO (100 ng/ml) significantly promoted CFU-GM formation in vitro. Various concentrations of ASPS and TPO also promoted the colony formation of HL-60 cells, the largest effect of ASPS was observed at a concentration of 100 µg/ml. There were no synergistic effects between TPO and ASPS on cellular proliferation. The results also showed that ASPS significantly protected HL-60 cells from apoptosis in condition of serum-free medium culture, suppressed caspase 3 activation, and reduced the cell apoptosis. It is concluded that ASPS can significantly promote the formation of bone marrow CFU-GM and the proliferation of HL-60 cells, the optimal concentration of ASPS is at 100 µg/ml. In the absence of serum inducing apoptosis, ASPS also significantly reduced the apoptosis of HL-60 cells via suppressing the activation of caspase-3.