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

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*

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

The chronic myelogenous leukemic K562 cell line carrying Bcr-Abl tyrosine kinase is considered as pluripotent hematopoietic progenitor cells expressing markers for erythroid, granulocytic, monocytic, and megakaryocytic lineages. Here we investigated the signaling modulations required for induction of erythroid differentiation of K562 cells. When the K562 cells were treated with herbimycin A (an inhibitor of protein tyrosine kinase), ras antisense oligonucleotide, and PD98059 (a specific inhibitor of MEK), inhibition of ERK/MAPK activity and cell growth, and induction of erythroid differentiation were observed. The ras mutant, pZIPRas61leu-transfected cells, K562-Ras61leu, have shown a markedly decreased cell proliferation rate with approximately 2-fold doubling time, compared with the parental K562 cells, and about 60% of these cells have shown the phenotype of erythroid differentiation. In addition, herbimycin A inhibited the growth rate and increased the erythroid differentiation, but did not affect the elevated activity of ERK/MAPK in the K562-Ras61leu cells. On the other hand, effects of PD98059 on the growth and differentiation of K562-Ras61leu cells were biphasic. At low concentration of PD98059, which inhibited the elevated activity of ERK/MAPK to the level of parental cells, the growth rate increased and the erythroid differentiation decreased slightly, and at high concentration of PD98059, which inhibited the elevated activity of ERK/MAPK below that of the parental cells, the growth rate turned down and the erythroid differentiation was restored to the untreated control level. Taken together, these results suggest that an appropriate activity of ERK/MAPK is required to maintain the rapid growth and transformed phenotype of K562 cells.
Androstadienes/pharmacology ; Ca(2+)-Calmodulin Dependent Protein Kinase ; Cell Differentiation/drug effects ; Enzyme Inhibitors/pharmacology ; Erythroid Progenitor Cells/physiology* ; Erythroid Progenitor Cells/cytology ; Erythropoiesis* ; Flavones/pharmacology ; Human ; K562 Cells ; Leukemia, Myeloid/pathology ; Oligonucleotides, Antisense/pharmacology ; Quinones/pharmacology ; ras Proteins/metabolism*

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

The effects of the Smad3- knockout on the hematopoiesis of mouse were investigated in this work. Five pairs of wild type and Smad3- null mice were studied. White blood cell(WBC), red blood cell(RBC) and platelet (PLT) counting of peripheral blood cells were performed with blood obtained from tails. And white blood cells were classified by their morphology. Bone marrow nucleated cells (BMNCs) were counted and classified. The CFU-GM, BFU-E, CFU-GEMM yields were measured in each pair of mice. CFU-S yield of each mouse was measured by injecting bone marrow cells into lethally irradiated 8-10 weeks old wild type female mice. And the pathomorphism of their bone marrows, spleens and livers were observed. As a result, WBC and PLT of Smad3- null mice were significantly higher than those in wild type mice. Smad3- null mice had much more proportion of granulocytes in classification. There wasn't any difference in RBC counting and BFU-E measurement. The yield of CFU-GM increased, while the yields of CFU-GEMM and CFU-S markedly reduced. Bone marrows are actively proliferative, with granulocytosis. The granulocyte/erythrocyte ratio increased. There were no obviously alterative in spleen and liver. Thus Smad3- knockout results in a decreased number of stem and progenitor cells. Moreover hematopoietic differentiation is abnormal with a tendency to forming more granulocytes and platelets. The effect of Smad3 on hematopoiesis is correlative to that of TGF-beta.
Animals ; Bone Marrow Cells ; cytology ; metabolism ; Cell Differentiation ; Erythrocytes ; cytology ; metabolism ; Erythroid Precursor Cells ; cytology ; metabolism ; Female ; Granulocyte-Macrophage Progenitor Cells ; cytology ; metabolism ; Granulocytes ; cytology ; metabolism ; Hematopoiesis ; genetics ; Mice ; Mice, Knockout ; Myeloid Progenitor Cells ; cytology ; metabolism ; Smad3 Protein ; genetics

OBJECTIVETo isolate expressed sequence tags (ESTs) related to K562 cells erythroid differentiation.

METHODSModified differential display reverse transcription polymerase chain reaction (DDRT-PCR) method was applied to identify differential ESTs in uninduced and induced K562 cells by HEMIN for 36 hours. Remarkable differential ESTs were firstly selected for cloning, sequencing and bioinformational analyzing. Several ESTs representing new sequence or providing functional clue were selected for Northern blot analysis.

RESULTSSixty differentially expressed cDNA fragments related to K562 cells inducted into erythroid differentiation by HEMIN were obtained. Among them, 38 were upregulated and 22 downregulated. Among the 40 differential ESTs selected for cloning, sequencing and bioinformationally analyzing, 23 were found to match to known GenBank sequences and 10 represented cDNA sequences with only dbEST database matches and 7 ESTs have no any database matches. The results of 6 in 8 ESTs selected for Northern blot analysis were shown to be consistent with the differential expressions of DDRT-PCR.

CONCLUSIONSThe improved DDRT-PCR method had successfully overcome the problem of false positive. These ESTs provide some clue for studying the molecular mechanisms and regulation network of erythroid differentiation.

Cell Differentiation ; drug effects ; Cell Transformation, Neoplastic ; drug effects ; Erythroid Cells ; cytology ; Expressed Sequence Tags ; Hemin ; pharmacology ; Humans ; K562 Cells ; cytology ; metabolism ; Sequence Tagged Sites

Stirred culture offers a number of advantages over static systems as it maintains a stable, homogeneous culture environment and is easy to scale-up. This paper focused on the development and application of stirred tank bioreactor to culture hematopoietic cells. Preliminary study of stirred culture of hematopoietic cells was carried out in cord blood mononuclear cells culture in spinner flask. The results showed that the amplification rates of total cell, CFU-GM and BFU-E, with the exception of CFU-Mk, were greater in spinner flask than T-flask. The number of total cells increased 20 fold after 14 days incubation in spinner flask. The amplification rates of CFU-GM, CFU-Mk and BFU-E reached maximum at 10th day, 10th day and 7th day respectively, and the maximal amplification rates were 9.2-fold, 5.5-fold and 2.4-fold respectively, whereas the rate of CD34+ cells in spinner flask was (6.7 +/- 4.0)-fold at day 10. These results indicated that the stirred culture system is better than the static culture systems for hematopoietic cell proliferation. The biocompatibility of cord blood MNC to different types of materials used in bioreactors was also tested. The results showed that glass, stainless steel 316L and polytetraflouroethylene (PTFE) supported the growth of hematopoietic cells well. A higher cell density was reached in stirred bioreactors with controlled pH and DO than static culture. These findings suggested that the controlled large-scale culture could be used to overcome the clinical shortage of hematopoietic cells.
Antigens, CD34 ; metabolism ; Bioreactors ; Cell Culture Techniques ; instrumentation ; methods ; Erythroid Precursor Cells ; cytology ; Fetal Blood ; cytology ; Granulocyte-Macrophage Progenitor Cells ; cytology ; Humans ; Polytetrafluoroethylene ; Stainless Steel

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

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