OBJECTIVE: To investigate the changes of GATA-1 protein expression during erythroid differentiation of K562 cells under hypoxia and how GATA-1 can regulate erythroid differentiation by up-regulating the expression of miR-451a and inhibiting the expression of 14-3-3ζ. METHODS: K562 cells were divided into 2 groups: the normoxia group and the hypoxia group, after the induction of hemin for 96 h, the positive cells rate of the benzidine staining, the mRNA expression of γ-globin and the expression of CD235a were detected, and the success of the model was verified. The changes of GATA-1 and miR-451a expression in the above-mentioned 2 groups, the changes of miR-451a expression after over-expressed GATA-1 were detected by Western blot and qRT-PCR. The cells in normoxic group and hypoxia group were divided into negative control group (NC group) and miR-451a over-expression group respectively, and the degree of erythroid differentiation in the four groups was judged according to the corresponding erythroid differentiation indexes, and the expression of 14-3-3ζ was detected by Western blot after over-expressed miR-451a. RESULTS: The positive cell rate of benzidine staining, mRNA expression of γ-globin and the expression of CD235a after 96 h induction by K562 cells under hypoxia were significantly higher than 0 h, suggesting that the erythroid differentiation model of K562 cells under hypoxia was replicated successfully. The expression levels of GATA-1 protein and miR-451a in the hypoxic group were significantly higher than that in the normoxic group (P<0.05). The expression level of miR-451a in hypoxia group was significantly higher than that in NC group after overexpressed GATA-1 (P<0.05). After over-expressed of miR-451a under hypoxia, the positive cell rate of benzidine staining, the mRNA expression level of γ-globin and the expression of CD235a were significantly higher than those in NC group (P<0.05). The expression level of 14-3-3ζ protein in miR-451a over-expressed group was lower than that in NC group under hypoxia (P<0.05). CONCLUSION Hypoxia can significantly increase the expression of GATA-1 protein, and the increase of GATA-1 expression can up-regulate the expression of miR-451a, thereby inhibiting the expression of 14-3-3ζ protein, which hinders the cell proliferation in erythroid differentiation model of K562 cells and plays an important role in promoting erythroid differentiation.
14-3-3 Proteins ; Cell Differentiation ; Erythroid Cells/metabolism* ; GATA1 Transcription Factor/metabolism* ; Humans ; Hypoxia ; K562 Cells ; MicroRNAs/genetics*

This study investigated the effects of N-acetylcysteine (NAC) and ascorbic acid (AA) on hemin-induced K562 cell erythroid differentiation and the role of reactive oxygen species (ROS) in this process. Hemin increased ROS levels in a concentration-dependent manner, whereas NAC and AA had opposite effects. Both NAC and AA eliminated transient increased ROS levels after hemin treatment, inhibited hemin-induced hemoglobin synthesis, and decreased mRNA expression levels of β-globin, γ-globin, and GATA-1 genes significantly. Pretreatment with 5,000 μmol/L AA for 2 h resulted in a considerably lower inhibition ratio of hemoglobin synthesis than that when pretreated for 24 h, whereas the ROS levels were the lowest when treated with 5,000 μmol/L AA for 2 h. These results show that NAC and AA might inhibit hemin-induced K562 cell erythroid differentiation by downregulating ROS levels.
Acetylcysteine ; pharmacology ; Antioxidants ; pharmacology ; Ascorbic Acid ; pharmacology ; Cell Differentiation ; drug effects ; Down-Regulation ; Erythroid Cells ; drug effects ; Hemin ; pharmacology ; Humans ; K562 Cells ; Reactive Oxygen Species ; metabolism

OBJECTIVETo investigate the effects of oxygen concentration and reactive oxygen species (ROS) on the biological characteristics of hematopoietic stem cells (HSC) and to analyzed the relationship among the oxygen concentration, ROS and the biological characteristics of mouse HSC through simulation of oxygen environment experienced by PB HSC during transplantation.

METHODSThe detection of reactive oxygen species (ROS), in vitro amplification, directional differentiation (BFU-E, CFU-GM, CFU-Mix), homing of adhesion molecules (CXCR4, CD44, VLA4, VLA5, P-selectin), migration rate, CFU-S of NOD/SCID mice irradiated with sublethal dose were performed to study the effect of oxgen concentration and reactive oxygen species on the biological characteristics of mouse BM-HSC and the relationship among them.

RESULTSThe oxygen concentrations lower than normal oxygen concentration (especially hypoxic oxygen environment) could reduce ROS level and amplify more Lin(-) c-kit(+) Sca-1(+) BM HSC, which was more helpful to the growth of various colonies (BFU-E, CFU-GM, CFU-Mix) and to maintain the migratory ability of HSC, thus promoting CFU-S growth significantly after the transplantation of HSC in NOD/SCID mice irradiated by a sublethal dose. BM HSC exposed to oxygen environments of normal, inconstant oxygen level and strenuously thanging of oxygen concentration could result in higher level of ROS, at the same time, the above-mentioned features and functional indicators were relatively lower.

CONCLUSIONThe ROS levels of BM HSC in PB HSCT are closely related to the concentrations and stability of oxygen surrounding the cells. High oxygen concentration results in an high level of ROS, which is not helpful to maintain the biological characteristics of BM HSC. Before transplantation and in vitro amplification, the application of antioxidancs and constant oxygen level environments may be beneficial for transplantation of BMMSC.

Animals ; Cell Differentiation ; Culture Media ; chemistry ; Erythroid Precursor Cells ; cytology ; Granulocyte-Macrophage Progenitor Cells ; cytology ; Hematopoietic Stem Cells ; cytology ; metabolism ; Mice ; Mice, Inbred NOD ; Mice, SCID ; Oxygen ; chemistry ; Reactive Oxygen Species ; metabolism

Myelodysplastic syndrome (MDS) is a heterogeneous disease characterized by dysplasia and ineffective hematopoiesis. The dysplasia is crucial in the diagnosis of MDS, but the morphologic abnormalities of bone marrow cells are not specific for MDS. When the morphological evaluation of marrow dysplasia and cytogenetics can not give enough informations, for diagnosis of MDS, the application of flow cytometry (FCM) for immunophenotyping in MDS will become particularly important. Multiparametric evaluation of myeloid, monocytic maturation and antigen expression pattern contribute to the identification of two or more aberrancies in MDS cases. FCM evaluation of erythroid dysplasia is particularly difficult, because of the limited availability of specific markers. By analyzing the proteins involved in cellular iron metabolism, MDS erythroid cells present an "iron-loaded" phenotype characterized by increased ferritin contents and reduced transferrin receptor, which reflects the degree of dysplasia assessed by morphology. The proportion of CD34(+) cells increased, abnormal expression of surface antigen is also important. The application of flow cytometry in detecting dysplasia of myelodysplastic syndrome is discussed in this article.
Bone Marrow Cells ; pathology ; Erythroid Cells ; metabolism ; Flow Cytometry ; Humans ; Myelodysplastic Syndromes ; blood ; diagnosis ; pathology ; Receptors, Transferrin ; metabolism

The aim of this study was to investigate the expression of transferrin receptor 2 (TfR2) mRNA in bone marrow mononuclear cells (BMMNC) of children with hyperplastic anemia (HA), to analyze the correlation of TfR2 mRNA expression level with Hb level, bone marrow erythroid hyperplasia, iron status in body and underlying diseases, and to evaluate the role of TfR2 in erythroid hemopoiesis and the useful value in diagnosis of HA. The experiment was divided into 2 groups: test group, in which 40 patients with HA were enrolled, and control group in which 10 patients without erythroid disorders and hematological malignancies confirmed by bone marrow examination were enrolled. The bone marrow samples of patients in mentioned above 2 groups were collected, the TfR2 mRNA expression in BMMNC of patients with HA was detected by fluorescence-quantitative PCR, the correlation of HA with bone marrow erythroid hyperplasia, iron status of body and underlying diseases was analyzed. The results showed that the relative level of TfR2 mRNA expression in HA patients was significantly higher than that in control patients. The TfR2 mRNA expression level negatively correlated with Hb level in peripheral blood (r = -0.715), while it positively correlated with ratio of bone marrow erythroblasts (r = 0.533). It is concluded that TfR2 mRNA expression in HA patients increases and closely correlates with hyperplasia status of bone marrow and anemia level in peripheral blood.
Adolescent ; Anemia ; metabolism ; pathology ; Bone Marrow Cells ; metabolism ; Case-Control Studies ; Child ; Child, Preschool ; Erythroid Precursor Cells ; metabolism ; Female ; Humans ; Infant ; Male ; RNA, Messenger ; metabolism ; Receptors, Transferrin ; metabolism

BACKGROUND AND OBJECTIVELeukemic microenvironment has a major role in the progression of leukemia. Leukemic cells can induce reversible changes in microenvironmental components, especially the stromal function which results in improved growth conditions for maintaining the malignant leukemic cells. This study aimed to investigate the survival advantage of leukemic cells over normal hematopoietic cells in stromal microenvironment in long term.

METHODSThe mice were injected intraperitoneally with N-N' ethylnitrosourea (ENU) to induce leukemia; the mice received injection of normal saline were used as control. At 180 days after ENU induction, the mice were killed and the bone marrows were cultured for 19 days. Colony-forming assays were used to analyze the formation of various cell colonies. The expression of Sca-1, CD146, VEGFR2, CD95, pStat3, pStat5, and Bcl-xL in marrow cells were detected by flow cytometry.

RESULTSLong-term leukemic bone marrow culture showed abnormal elongated stromal fibroblasts with almost absence of normal hematopoietic cells. Adherent cell colonies were increased, but CFU-F and other hematopoietic cell colonies were significantly decreased in leukemia group (P<0.001). Primitive progenitor-specific Sca-1 receptor expression was decreased with subsequent increased expression of CD146 and VEGFR-2 in leukemic bone marrow cells. Decreased Fas antigen expression with increased intracellular pStat3, pStat5 and Bcl-xL proteins were observed in leukemic bone marrow cells.

CONCLUSIONSStromal microenvironment shows altered morphology and decreased maturation in leukemia. Effective progenitor cells are decreased in leukemia with increased leukemia-specific cell population. Leukemic microenvironment plays a role in promoting and maintaining the leukemic cell proliferation and survivability in long term.

Animals ; Antigens, Ly ; metabolism ; Bone Marrow Cells ; metabolism ; pathology ; CD146 Antigen ; metabolism ; Cell Count ; Cells, Cultured ; Colony-Forming Units Assay ; Erythroid Precursor Cells ; metabolism ; pathology ; Ethylnitrosourea ; Female ; Fibroblasts ; metabolism ; pathology ; Granulocyte-Macrophage Progenitor Cells ; metabolism ; pathology ; Granulocytes ; metabolism ; pathology ; Hematopoiesis ; Hematopoietic Stem Cells ; metabolism ; pathology ; Leukemia ; chemically induced ; metabolism ; pathology ; Male ; Membrane Proteins ; metabolism ; Mice ; Myeloid Progenitor Cells ; metabolism ; pathology ; Phenotype ; STAT3 Transcription Factor ; metabolism ; STAT5 Transcription Factor ; metabolism ; Tumor Microenvironment ; physiology ; Vascular Endothelial Growth Factor Receptor-2 ; metabolism ; bcl-X Protein ; metabolism ; fas Receptor ; metabolism

OBJECTIVETo investigate the effects of combined use of low-dose hydroxyurea (HU) and sodium butyrate (NaB) on the expression of 7 globin genes (zeta, alpha, epsilon, Ggamma, Agamma, delta, and beta) in human erythroid progenitor cells.

METHODSHuman erythroid progenitor cells were cultured using a two-step liquid culture system and treated with HU and NaB either alone or in combination. The inhibitory effects of the agents on the cell growth were monitored with trypan blue exclusion assay, and the changes in the mRNA of the 7 globin genes were detected using RT-PCR.

RESULTSLow-dose HU combined with NaB resulted in significantly lower inhibition rate of the erythroid progenitor cells than routine dose HU and NaB used alone (28.56% and 38.80%, respectively, P<0.05). Compared with untreated cells (0.653-/+0.092 and 0.515-/+0.048), HU combined with NaB significantly increased the expression of Ggamma-and Agamma- mRNA (1.203-/+0.018 and 0.915-/+0.088, respectively, P<0.05), and HU and NaB used alone produced similar effects (1.305-/+0.016 and 0.956-/+0.029 for HU, and 1.193-/+0.070 and 0.883-/+0.012 for NaB, P>0.05). HU and NaB, either used alone or in combination or at different doses, caused no significant changes in the other globin genes (zeta, alpha, epsilon, delta and beta) (P>0.05).

CONCLUSIONLow-dose HU combined with NaB can up-regulate gamma globin gene expression, especially Ggamma-mRNA expression, to decrease the growth inhibition on human erythroid progenitor cells in vitro, but produces no significant effect on the expressions of zeta, alpha, epsilon, delta and beta genes.

Anemia, Sickle Cell ; genetics ; Butyrates ; administration & dosage ; pharmacology ; therapeutic use ; Cells, Cultured ; Drug Therapy, Combination ; Erythroid Precursor Cells ; cytology ; drug effects ; physiology ; Erythropoiesis ; drug effects ; Humans ; Hydroxyurea ; administration & dosage ; pharmacology ; therapeutic use ; RNA, Messenger ; genetics ; metabolism ; gamma-Globins ; genetics ; metabolism

OBJECTIVE: To determine the expression of DLK1 gene in acute leukemias (AL) and its function in erythroid differentiation of K562 cells. METHODS: We detected the expression of DLK1 gene in 65 different acute leukemia categories (a test group) and 34 normal bone marrow controls (a control group) with RT-PCR. DLK1 protein in 20 out of the 65 AL patients and 13 of the 34 controls was assayed by Western blot. The K562 cell line was induced to erythroid differentiation by hemin. We observed the relationship between its expression and erythroid differentiation. RESULTS: Both leukemia cells and normal marrow cells expressed DLK1. The expression of DLK1 mRNA in patients in the test group was higher than that in the control group (P=0.018), while there was no significance between acute lymphoblastic leukemia and acute myelogenous leukemia (P>0.05).The expression of DLK1 mRNA in the test group at onset had no relation with the WBC and platelet count in the total peripheral blood, and the same was true for blast cell rates in bone marrow cells.The level of DLK1 protein in the test group was higher than that in the control group, which was consistent with the mRNA expression (P=0.042). The expression of DLK1 mRNA decreased gradually with K562 cells towards hemin-induced erythroid differentiation. CONCLUSION DLK1 gene may be involved in leukemia,but the mRNA level of DLK1 has no relation with some clinical characteristics of AL patients at onset. DLK1 may inhibit the erythroid differentiation of K562 cells.
Acute Disease ; Adolescent ; Adult ; Aged ; Calcium-Binding Proteins ; Case-Control Studies ; Cell Differentiation ; drug effects ; genetics ; Cell Transformation, Neoplastic ; genetics ; Child ; Child, Preschool ; Erythroid Cells ; pathology ; Erythroid Precursor Cells ; pathology ; Female ; Humans ; Intercellular Signaling Peptides and Proteins ; genetics ; metabolism ; K562 Cells ; Leukemia ; genetics ; metabolism ; Male ; Membrane Proteins ; genetics ; metabolism ; Middle Aged ; RNA, Messenger ; genetics ; metabolism ; Young Adult

The aim of study was to explore the potential of human erythroid membrane associated protein (ERMAP) gene in erythroid cell differentiation and development, mononuclear cells (MNCs) were isolated from umbilical cord blood and induced to erythroid cell differentiation by SCF, IL-3 and EPO. The cell morphology was observed by using optical microscopy, the positive rate of cells was counted by biphenylamine staining and the ratios of CD36+/CD235a-, CD36+/CD235a+, CD36-/CD235a+ cells were detected by flow cytometry, the change of human ermap gene expression level was analyzed by using fluorescent quantitative PCR (FQ-PCR). The results showed that the ermap gene expression level increased while MNCs were induced to erythroid lineage after treatment with SCF, IL-3 and EPO. It is concluded that the human ermap gene plays an important role in differentiation and development of erythroid cells.
Blood Group Antigens ; genetics ; metabolism ; Butyrophilins ; Cell Differentiation ; genetics ; Cells, Cultured ; Erythroid Cells ; cytology ; Fetal Blood ; cytology ; Humans ; Leukocytes, Mononuclear ; cytology ; metabolism ; Polymerase Chain Reaction ; methods

OBJECTIVETo explore the biological effect of Notch ligand Delta-1 (Notch L delta-1) on the sIL-6R during the differentiation of erythroid hematopoiesis.

METHODSMononuclear cells (MNCs) was isolated from the normal cord blood using Ficoll graduation solution. MNCs were enriched for CD34(+) CD38(-) cells by CD34 immunomagnetic beads and a FACS Vantage. CD34(+) CD38(-) cells was cultured for 7 days in the presence of SCF, Flt3L, TPO and IL-3 (4GFs). The cultured cells was detected for the expression of IL-6R and GPA. The subsequently enriched CD36(+) erythroid progenitors were sorted for cells with IL-6R(+) and IL-6R(-) using FACS Vantage. The CD36(+) GPA(-) IL-6R(-) cells were respectively cultured in the 4GFs, 4GFs + IL-6 or 4GFs + FP6 containing medium in the presence or absence of Notch L delta-1 for 14 days and CD36(+) GPA high red cells were counted.

RESULTSIL-6R cells accounted for 95% of CD36(+) GPA(+) cells. The CD36(+) GPA(-) cells was clearly divided into IL-6R(+) (46%) and IL-6R(-) (54%) subpopulations, the IL-6R(+) cell subpopulation formed only a few GM colonies (2.1 +/- 1.8) and a greater number of BFU-E colonies were generated from the IL-6R(-) subpopulation (58.2 +/- 18.1) (P < 0.05). The number of CD36(+) GPA high cell was (1.400 +/- 0.180) x 10(6) in the presence of FP6, lower than that [(2.460 +/- 0.190) x 10(6)] in the presence of FP6 + Notch L delta-1 (P < 0.05).

CONCLUSIONNotch L delta-1 enhances the sIL-6R-mediated effects of IL-6 on the generation of erythroid cells.

ADP-ribosyl Cyclase 1 ; Antigens, CD34 ; Cell Differentiation ; drug effects ; physiology ; Cells, Cultured ; Erythroid Precursor Cells ; cytology ; drug effects ; Humans ; Interleukin-6 ; metabolism ; physiology ; Intracellular Signaling Peptides and Proteins ; Membrane Proteins ; pharmacology ; Receptors, Interleukin-6 ; metabolism ; physiology