Mitochondrial metabolism is crucial for providing energy and heme precursors during erythroid development. Oxoglutarate dehydrogenase complex (OGDC) is a key enzyme in the mitochondrial tricarboxylic acid (TCA) cycle, and its level gradually increases during erythroid development, indicating its significant role in erythroid development. The aim of the present study was to explore the role and mechanism of OGDC in erythroid development. In this study, we treated erythroid progenitor cells with CPI-613, a novel lipoic acid analog that competitively inhibits OGDC. The results showed that CPI-613 inhibited erythropoietin (EPO)-induced differentiation and enucleation of human CD34⁺ hematopoietic stem cells into erythroid cells, suppressed cell proliferation, and induced apoptosis. The results of in vivo experiments showed that CPI-613 also hindered the recovery of mice from acute hemolytic anemia. Further mechanism research results showed that CPI-613 increased reactive oxygen species (ROS) in erythroid progenitor cells, inhibited mitochondrial respiration, caused mitochondrial damage, and suppressed heme synthesis, thereby inhibiting erythroid differentiation. Clinical research results showed that oxoglutarate dehydrogenase (OGDH) protein expression levels were up-regulated in bone marrow cells of polycythemia vera (PV) patients. Treatment with CPI-613 significantly inhibited the excessive proliferation and differentiation of erythroid progenitor cells of the PV patients. These findings demonstrates the critical role of OGDC in normal erythroid development, suggesting that inhibiting its activity could be a novel therapeutic strategy for treating PV.
Animals ; Humans ; Mitochondria/metabolism* ; Mice ; Ketoglutarate Dehydrogenase Complex/physiology* ; Cell Differentiation/drug effects* ; Cells, Cultured ; Erythropoiesis/drug effects* ; Reactive Oxygen Species/metabolism* ; Cell Proliferation/drug effects* ; Erythroid Precursor Cells/cytology* ; Apoptosis/drug effects* ; Thioctic Acid/pharmacology* ; Caprylates ; Sulfides

Transcription factor PU.1, as a core member of the ETS family, plays a pivotal role in the multi-lineage differentiation of hematopoietic stem cells, particularly in the regulation of erythroid differentiation. PU.1 orchestrates the process of hematopoietic stem cell differentiation towards erythroid cells by modulating the transcription of lineage-determining factors and interacting with other key transcription factors in a fine-tuned manner. PU.1 plays an irreplaceable role in the development and function of red blood cells, with its abnormal expression closely related to the occurrence and progression of various blood diseases, including leukemia, myelodysplastic syndromes, and various types of anemia. This article comprehensively analyzes the functional roles and molecular mechanisms of PU.1 in various stages of erythroid differentiation, as well as its potential roles in related blood diseases. This review not only deepens our understanding of the mechanism by which PU.1 regulates erythroid differentiation, but also provides theoretical grounds for blood disease therapies based on PU.1.
Humans ; Proto-Oncogene Proteins/genetics* ; Trans-Activators/genetics* ; Cell Differentiation/physiology* ; Hematologic Diseases/physiopathology* ; Erythroid Cells/cytology* ; Animals ; Erythropoiesis/physiology*

Macrophages have two major roles in regulating the dynamic equilibrium in erythropoiesis, promoting the differentiation and maturation of nucleated red blood cells into reticulocytes and removing old red blood cells. A recent mouse study has demonstrated that the phenotype of macrophages in erythroblastic islands is CD169+ VCAM-1+ ER-HR3+ CD11b+ F4/80+ Ly-6G+. Molecular connections between erythroid progenitor cells and central macrophages help to maintain the function and integrity of erythroblastic islands. New research advances in Kruppel-like factor 1 (KLF1) provide new evidence for the important role of macrophages in erythroblastic islands. Macrophages play an important role in erythropoiesis both in sickness and in health, and provide a potential targeted therapy for diseases such as polycythemia vera and beta-thalassemia in the future.
Animals ; Erythropoiesis ; Humans ; Integrin alpha4beta1 ; physiology ; Kruppel-Like Transcription Factors ; physiology ; Macrophages ; physiology ; Mice ; Phenotype ; Vascular Cell Adhesion Molecule-1 ; physiology

To demonstrate the effect of AB serum on terminal erythroid differentiation ex vivo.
 Methods: After separation of CD34+ cells from cord blood, the cells were cultured and divided into a control group and an experimental group. The effects of AB serum were examined by the expressions of different markers (GPA, Band3 and α4-integrin) for erythroblast differentiation and enucleation by flow cytometry. 
 Results: The CD34+ cells were successfully differentiated to enucleated red blood cells. There were evident differences among the expressions of GPA, Band3 and α4-integrin between the 2 groups. The percentage of GPA positive cells in the experimental group was bigger than that in the control group in every time point. The expression of Band3 in the experimental group was higher than that in the control group. The expression of α4-integrin in the experimental group was lower than that in the control group. In addition, the enucleation rate in the experimental group was higher than that in the control group.
 Conclusion: AB serum can promote the cell differentiation and enucleation during terminal erythroid differentiation in vitro.
ABO Blood-Group System ; blood ; physiology ; Anion Exchange Protein 1, Erythrocyte ; metabolism ; Antigens, CD34 ; blood ; Cell Differentiation ; genetics ; physiology ; Cell Nucleus ; Cells, Cultured ; Erythrocytes ; physiology ; ultrastructure ; Erythropoiesis ; genetics ; physiology ; Fetal Blood ; cytology ; physiology ; Flow Cytometry ; Glycophorins ; metabolism ; Humans ; Integrin alpha4beta1 ; metabolism

Erythropoiesis ; physiology ; Humans ; Mitochondria ; physiology ; Mitochondrial Degradation

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

In men, testosterone (T) deficiency is associated with decreased physical performance, as defined by adverse traits in body composition, namely increased body fat content and reduced muscle mass. Physical abilities in androgen-deficient men are further attenuated by lower oxygen supply due to decreased hemoglobin concentrations and by poor glucose utilization. Dysthymia and a lack of necessary aggressiveness also contribute to deteriorate physical effectiveness. Substitution of T can improve lipid and insulin metabolism as well as growth of muscle fibers and decreasing fat depots, which consequently will result in changes of body composition. Increment of bone density will further contribute to increase physical fitness. The effects of T replacement therapy (TRT) are strongly influenced by age, training, and also pharmacogenetics: the CAG repeat polymorphism in exon 1 of the androgen receptor (AR) gene modulates androgen effects. In vitro, transcription of androgen-dependent target genes is attenuated with increasing length of triplet residues. Clinically, the CAG repeat polymorphism causes significant modulations of androgenicity in healthy eugonadal men as well as efficacy of TRT. Thresholds at which T treatment should be initiated, as well as androgen dosage, could be tailored according to this polymorphism.
Affect ; Body Composition ; Erythropoiesis ; Glucose ; metabolism ; Hormone Replacement Therapy ; Humans ; Male ; Pharmacogenetics ; Polymorphism, Genetic ; Receptors, Androgen ; genetics ; physiology ; Testosterone ; administration & dosage ; pharmacology

OBJECTIVETo explore impaired erythropoiesis and relative inadequacy of erythropoietin production in the anemic cancer patients and the correlation of tumor necrosis factor-alpha (TNF-alpha) or interferon-gamma (IFN-gamma) with inadequate erythropoietin (EPO) response and impaired erythropoiesis in cancer patients with anemia.

METHODSFifty adult anemic and 15 non-anemic tumor patients were studied. Serum EPO levels were measured by radioimmunoassay (RIA) and serum soluble transferrin receptor (sTfR). TNF-alpha and IFN-gamma levels by enzyme-linked immunosorbent assay (ELISA). Log transformed EPO and sTfR values were used in statistical analysis. The R correlation analyses were performed.

RESULTSThe mean serum immunoreactive erythropoietin level in anemic cancer patients [(23.11 +/- 10.00) IU/L] was not significantly higher than in healthy people (P = 0.053), but significantly lower than in IDA patients with similar degree of anemia [(43.00 +/- 22.00) IU/L, P < 0.01]. Both O/P EPO [0.88 (0.54-1.10)] and O/P sTfR [0.89 (0.57-1.22)] were significantly lower in anemic cancer patients than in controls and in non-anemic cancer patients. There was no significant difference between the latter two groups. Furthermore, the expected inverse linear relation between serum EPO and hemoglobin levels was absent in the anemic cancer patients, and so did the relation between serum sTfR and hemoglobin levels. There was no correlation between O/P EPO and O/P sTfR. The serum levels of both TNF-alpha and IFN-gamma in anemic cancer patients [(25.75 +/- 26.71) ng/L, (50.49 +/- 42.12) ng/L, respectively] were significantly higher than those in healthy controls (both P < 0.01) or in nonanemic cancer patients (both 0.01 < P < 0.05), and so did between non-anemic cancer patients and controls. The serum levels of TNF-alpha were inversely correlated with hemoglobin levels (r = - 0.40, P = 0.004), O/P EPO (r = -0.32, P = 0.025) or O/P sTfR (r = -0.36, P = 0.01); while serum levels of IFN-gamma were inversely correlated with hemoglobin levels (r = -0.36, P = 0.01) or O/P sTfR (r = 0.39, P = 0.006), but not with O/P EPO. Conclusions Anemia of cancer is due to impaired erythropoiesis and relative inadequacy of EPO production. TNF-alpha might inhibit EPO production and erythropoiesis, while IFN-gamma maybe directly inhibit erythropoiesis and be independent of EPO response inadequacy.

Adolescent ; Adult ; Aged ; Anemia ; blood ; etiology ; physiopathology ; Erythropoiesis ; physiology ; Erythropoietin ; biosynthesis ; blood ; Female ; Humans ; Interferon-gamma ; blood ; Male ; Middle Aged ; Neoplasms ; complications ; Receptors, Transferrin ; blood ; Tumor Necrosis Factor-alpha ; metabolism

BACKGROUNDPolycythemia vera (PV) is a malignant disorder of hemaopoietic stem cells which is characterized by clonal hyperproliferation and a low rate of apoptosis. This study was to assess endogenous erythroid colony (EEC) formation in the bone marrow of PV patients and determine its clinical significance.

METHODSThe bone marrow mononuclear cells of 26 patients with PV, 2 patients with secondary erythrocytosis (SE), and 19 normal controls were cultured by Marsh's method for EEC evaluation, and the clinical significance was evaluated.

RESULTSEECs appeared in 25 patients with PV but not in 2 patients with SE and 19 normal controls. The number of EECs and the EEC ratio [EEC/erythropoietin (EPO)-dependent colony forming unit-erythroid (CFU-E)] in PV patients positively correlated with hemoglobin (Hb) levels. Their EEC number did not correlate with white blood cell (WBC) counts, platelet (PLT) counts, or leukocyte alkaline phosphatase (LAP) scores. Their EEC did not correlate with serum EPO levels. Fifteen patients with PV were treated with hydroxyurea (Hu) and/or interferon-alpha (IFN-alpha). Their EEC ratio before treatment positively correlated with the treatment time required for complete remission (CR) and negatively correlated with the time before relapse. The EEC numbers of 7 PV patients treated with Hu/IFN-alpha decreased after the blood cell counts dropped to normal levels. There was a positive correlation between the EEC ratio and the incidence of attacks of vascular thrombosis in PV patients. The numbers of apoptosised bone marrow mononuclear cells in PV patients were lower than those in normal controls. The EEC numbers of PV patients negatively correlated with the rate of apoptosis of bone marrow mononuclear cells.

CONCLUSIONSEEC formation is characteristic in PV patients. EEC number in PV patients positively correlates with Hb levels, the time required for CR, and the incidence of attacks of vascular thrombosis. EEC number negatively correlates with the time before relapse. Bone marrow suppressive treatment might decrease EEC number. Thus, EEC number is a sensitive and specific parameter reflecting the abnormal hematopoietic clone burden induced by polycythemia vera. EEC number is an important diagnostic parameter for PV patients.

Adult ; Aged ; Apoptosis ; Colony-Forming Units Assay ; Erythroid Precursor Cells ; physiology ; Erythropoiesis ; Erythropoietin ; blood ; Female ; Humans ; Male ; Middle Aged ; Polycythemia Vera ; blood ; therapy ; Thrombosis ; epidemiology

Evaluation of the mechanism of anemia in cancer patients might help to select patients for the more efficient use of erythropoietin (EPO, a growth factor for erythroid precursor cells). For this, we investigated whether the production of EPO responds to anemia and the bone marrow responds to EPO appropriately, and whether chronic inflammation is inhibitory to erythropoiesis in anemic cancer children. Serum levels of EPO, soluble transferrin receptor (sTfR), tumor necrosis factor (TNF)-alpha, and erythrocyte sedimentation rate (ESR) in anemic cancer children were measured by enzyme-linked immunosorbent assay and then the correlation coefficients between those parameters and hemoglobin (Hb) were determined. Both in leukemia and in solid tumor patients, there were significant inverse correlations between Hb and EPO (leukemia: tau=-0.547, p<0.0001; solid tumor: tau=-0.591, p<0.0001), and between sTfR and EPO (leukemia: tau=-0.223, p<0.05; solid tumor: tau=-0.401, p<0.05). In contrast, sTfR showed a correlation with Hb in leukemia (tau=0.216, p<0.05) but not in solid tumor patients. sTfR was suppressed in 53% of anemic episodes of leukemia and 78% of those of solid tumor patients. Our results suggest that in cancer children, the EPO production is not defective and chronic inflammation is not inhibitory to erythropoiesis. Rather, the defective erythropoiesis itself is thought to be responsible for the anemia.
Anemia/etiology/*physiopathology ; Blood Sedimentation ; Bone Marrow/physiology ; Child ; Erythropoiesis/*physiology ; Erythropoietin/blood ; Female ; Humans ; Male ; Neoplasms/complications/*physiopathology ; Receptors, Transferrin/blood ; Solubility ; Tumor Necrosis Factor-alpha/metabolism