Search

SF3B1 mutations, which occur in 20% of patients with myelodysplastic syndromes (MDS), are the hallmarks of a specific MDS subtype, MDS with ringed sideroblasts (MDS-RS), which is characterized by the accumulation of erythroid precursors in the bone marrow and primarily affects the elderly population. Here, using single-cell technologies and functional validation studies of primary SF3B1-mutant MDS-RS samples, we show that SF3B1 mutations lead to the activation of the EIF2AK1 pathway in response to heme deficiency and that targeting this pathway rescues aberrant erythroid differentiation and enables the red blood cell maturation of MDS-RS erythroblasts. These data support the development of EIF2AK1 inhibitors to overcome transfusion dependency in patients with SF3B1-mutant MDS-RS with impaired red blood cell production.SignificanceMDS-RS are characterized by significant anemia. Patients with MDS-RS die from a shortage of red blood cells and the side effects of iron overload due to their constant need for transfusions. Our study has implications for the development of therapies to achieve long-lasting hematologic responses. This article is highlighted in the In This Issue feature, p. 476.

Myeloproliferative neoplasms (MPNs) cause the over-production of blood cells such as erythrocytes (polycythemia vera) or platelets (essential thrombocytosis). JAK2 V617F is the most prevalent somatic mutation in many MPNs, but previous modeling of this mutation in mice relied on transgenic overexpression and resulted in diverse phenotypes that were in some cases attributed to expression level. CRISPR-Cas9 engineering offers new possibilities to model and potentially cure genetically encoded disorders via precise modification of the endogenous locus in primary cells. Here we develop "scarless" Cas9-based reagents to create and reverse the JAK2 V617F mutation in an immortalized human erythroid progenitor cell line (HUDEP-2), CD34+ adult human hematopoietic stem and progenitor cells (HSPCs), and immunophenotypic long-term hematopoietic stem cells (LT-HSCs). We find no overt in vitro increase in proliferation associated with an endogenous JAK2 V617F allele, but co-culture with wild type cells unmasks a competitive growth advantage provided by the mutation. Acquisition of the V617F allele also promotes terminal differentiation of erythroid progenitors, even in the absence of hematopoietic cytokine signaling. Taken together, these data are consistent with the gradually progressive manifestation of MPNs and reveals that endogenously acquired JAK2 V617F mutations may yield more subtle phenotypes as compared to transgenic overexpression models.

Objective To investigate the role and mechanism of erythroid precursor cells (EPC) and its subtypes in Alzheimer's disease (AD). Methods The patients with AD (AD group) firstly diagnosed and treated in Qinghai Provincial People's Hospital from October 2018 to October 2019 were included, and olanzapine combined with donepezil were used for treatment; while 30 healthy volunteers were selected as the control group. The proportion of EPC, CD45+EPC and CD45-EPC in peripheral blood in control group and AD group before and after treatment was detected and sorted by flow cytometry. Primary cortical neurons were used to construct AD cells model, flow cytometry was used to detect the apoptosis of neurons in control group, AD model group, CD45+EPC group, CD45-EPC group and Artemin block group. Results There was no significant difference in the proportion of EPC in peripheral blood between AD group and control group, or between AD group before and after treatment (P＞0.05, for all). However, the proportion of CD45+EPC subtype (t=7.277, P=0.000) and ROS content (t=10.817, P=0.000) in AD group before treatment were higher than those in control group. The proportion of CD45-EPC subtype (t=7.277, P=0.000) and Artemin content (t=6.547, P=0.000) were lower than those in control group, but there were no significant differences in proportion of CD45+EPC and CD45-EPC subtypes, ROS and Artemin contents before and after treatment in AD group (P＞0.05, for all). Neuronal apoptosis experiment showed the proportion of neuronal apoptosis in different treatment groups was significantly different (F=25.662, P=0.000). The proportion of neuronal apoptosis in AD model group (t=9.330, P=0.000), CD45+EPC group (t=14.362, P=0.000), CD45-EPC group (t=2.423, P=0.036) and Artemin block group (t=9.970, P=0.000) were higher than those in control group. AD model group (t=4.548, P=0.001), CD45+EPC group (t=8.759, P=0.000), Artemin block group (t=5.387, P=0.000) were higher than those in CD45-EPC group. CD45+EPC group was also higher than that in AD model group (t=5.091, P=0.000) and Artemin block group (t=3.175, P=0.004). Conclusions The proportion of CD45+EPC subtype in peripheral blood of AD patients was significantly increased and the proportion of CD45-EPC subtype was decreased. CD45-EPC subtype can reduce the neuronal apoptosis induced by AD by secreting Artemin.

Human parvovirus B19 is a known etiological agent for aplastic crisis in patients with chronic hemolysis and immunodeficiencies. The aplastic state caused in healthy children and adults is usually transient as compared to the more severe form seen in at risk population. Here we present a case of adult immunocompetent male with megaloblastic anemia complicated by aplastic crisis induced by parvovirus B19. A 23 year old male on treatment for megaloblastic anemia, presented with breathlessness, weakness and mild hepatomegaly. Laboratory investigations revealed an Hb-5.7g/dl, reticulocyte count-0.13% and absolute reticulocyte count of 0.00 × 106/μL. His serum vitamin B levels were 974 pg/ml. Bone marrow studies were 12 done to evaluate the cause. Aspiration smears showed erythroid suppression with large proerythroblasts having vacuolated cytoplasm and eosinophilic intranuclear inclusions (Lantern cells). Biopsy showed proerythroblasts with nucleomegaly, pale chromatin and eosinophilic intranuclear inclusions, morphologically suggestive of parvovirus infection. Parvovirus B19DNA was isolated by TaqMan PCR. Patient was managed by red blood cell transfusion to which he responded well. Aplastic crisis due to parvovirus B19 has been reported in patients with sickle cells anemia, thalassemia, haematological malignancies, transplant recipients and acquired immunodeficiency states. Development of erythroblastopenia due to parvovirus in background of nutritional anemia is unusual. A bone marrow examination in such a scenario helps to exclude causes like myelodysplastic syndrome, lymphoproliferative disorder and provides clues for diagnosis of parvovirus infection which is a treatable etiology.

Human parvovirus B19 is a known etiological agent for aplastic crisis in patients with chronic hemolysis and immunodeficiencies. The aplastic state caused in healthy children and adults is usually transient as compared to the more severe form seen in at risk population. Here we present a case of adult immunocompetent male with megaloblastic anemia complicated by aplastic crisis induced by parvovirus B19. A 23 year old male on treatment for megaloblastic anemia, presented with breathlessness, weakness and mild hepatomegaly. Laboratory investigations revealed an Hb-5.7g/dl, reticulocyte count-0.13% and absolute reticulocyte count of 0.00 × 106/µL. His serum vitamin B levels were 974 pg/ml. Bone marrow studies were 12 done to evaluate the cause. Aspiration smears showed erythroid suppression with large proerythroblasts having vacuolated cytoplasm and eosinophilic intranuclear inclusions (Lantern cells). Biopsy showed proerythroblasts with nucleomegaly, pale chromatin and eosinophilic intranuclear inclusions, morphologically suggestive of parvovirus infection. Parvovirus B19DNA was isolated by TaqMan PCR. Patient was managed by red blood cell transfusion to which he responded well. Aplastic crisis due to parvovirus B19 has been reported in patients with sickle cells anemia, thalassemia, haematological malignancies, transplant recipients and acquired immunodeficiency states. Development of erythroblastopenia due to parvovirus in background of nutritional anemia is unusual. A bone marrow examination in such a scenario helps to exclude causes like myelodysplastic syndrome, lymphoproliferative disorder and provides clues for diagnosis of parvovirus infection which is a treatable etiology. [ABSTRACT FROM AUTHOR]

Unlimited self renewal capacity and differentiation potential make human pluripotent stem cells (PSC) a promising source for the ex vivo manufacture of red blood cells (RBCs) for safe transfusion. Current methods to induce erythropoiesis from PSC suffer from low yields of RBCs, most of which are immature and contain embryonic and fetal rather than adult hemoglobins. We have previously shown that homodimerization of the intracellular component of MPL (ic-MPL) induces erythropoiesis from human cord blood progenitors. The goal of this study was to investigate the potential of ic-MPL dimerization to induce erythropoiesis from human embryonic stem cells (hESCs) and to identify the signaling pathways activated by this strategy. We present here the evidence that ic-MPL dimerization induces erythropoietin (EPO)-independent erythroid differentiation from hESC by inducing the generation of erythroid progenitors and by promoting more efficient erythroid maturation with increased RBC enucleation as well as increased gamma:epsilon globin ratio and production of beta-globin protein. ic-MPL dimerization is significantly more potent than EPO in inducing erythropoiesis, and its effect is additive to EPO. Signaling studies show that dimerization of ic-MPL, unlike stimulation of the wild type MPL receptor, activates AKT in the absence of JAK2/STAT5 signaling. AKT activation upregulates GATA-1 and FOXO3 transcriptional pathways with resulting inhibition of apoptosis, modulation of cell cycle, and enhanced maturation of erythroid cells. These findings open up potential new targets for the generation of therapeutically relevant RBC products from hPSC.

Although formaldehyde (FA) has been classified as a human leukemogen, the mechanisms of leukemogenesis remain elusive. Previously, using colony-forming assays in semi-solid media, we showed that FA exposure in vivo and in vitro was toxic to human hematopoietic stem/progenitor cells. In the present study, we have applied new liquid in vitro erythroid expansion systems to further investigate the toxic effects of FA (0-150 μM) on cultured mouse and human hematopoietic stem/progenitor cells. We determined micronucleus (MN) levels in polychromatic erythrocytes (PCEs) differentiated from mouse bone marrow. We measured cell growth, cell cycle distribution, and chromosomal instability, in erythroid progenitor cells (EPCs) expanded from human peripheral blood mononuclear cells. FA significantly induced MN in mouse PCEs and suppressed human EPC expansion in a dose-dependent manner, compared with untreated controls. In the expanded human EPCs, FA slightly increased the proportion of cells in G2/M at 100 μM and aneuploidy frequency in chromosomes 7 and 8 at 50 μM. Our findings provide further evidence of the toxicity of FA to hematopoietic stem/progenitor cells and support the biological plausibility of FA-induced leukemogenesis.

Purpose of Review: Recent work reveals that cell cycle duration and structure are remodeled in lock-step with distinct stages of erythroid differentiation. These cell cycle features have regulatory roles in differentiation, beyond the generic function of increasing cell number., Recent Findings: Developmental progression through the early erythroid progenitor stage (known as colony-forming-erythroid, or 'CFU-e') is characterized by gradual shortening of G1 phase of the cycle. This process culminates in a key transcriptional switch to erythroid terminal differentiation (ETD) that is synchronized with, and dependent on, S phase progression. Further, the CFU-e/ETD switch takes place during an unusually short S phase, part of an exceptionally short cell cycle that is characterized by globally fast replication fork speeds. Cell cycle and S phase speed can alter developmental events during erythroid differentiation, through pathways that are targeted by glucocorticoid and erythropoietin signaling during the erythroid stress response., Summary: There is close inter-dependence between cell cycle structure and duration, S phase and replication fork speeds, and erythroid differentiation stage. Further, modulation of cell cycle structure and speed cycle impacts developmental progression and cell fate decisions during erythroid differentiation. These pathways may offer novel mechanistic insights and potential therapeutic targets., (Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.)

Background: Erythropoiesis is a complex developmental process in which a hematopoietic stem cell undergoes serial divisions and differentiates through well-defined stages to give rise to red blood cells. Over the last decades, several protocols have been developed to perform ex vivo erythroid differentiation, allowing investigation into erythropoiesis and red cell production in health and disease., Results: In the current study, we compared the two commonly used protocols by assessing the differentiation kinetics, synchronisation, and cellular yield, using molecular and cellular approaches. Peripheral blood CD34 + cells were cultured in a two-phase (2P) or a four-phase (4P) liquid culture (LC) and monitored for 20 days. Both protocols could recapitulate all stages of erythropoiesis and generate reticulocytes, although to different extents. Higher proliferation and viability rates were achieved in the 4P-LC, with a higher degree of terminal differentiation and enucleation, associated with higher levels of the erythroid-specific transcription factors GATA-1, KLF-1, and TAL-1. Although the 2P-LC protocol was less efficient regarding terminal erythroid differentiation and maturation, it showed a higher yield of erythroid progenitors in the erythropoietin (EPO)-free expansion phase., Conclusions: We provide data supporting the use of one protocol or the other to study the biological processes occurring in the early or late stages of erythroid differentiation, depending on the physiological process or pathological defect under investigation in a given study., Competing Interests: Declaration of competing interest The authors declare that they have no competing interests., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

We generated a human induced pluripotent stem cell (hiPSC) line from erythroid progenitor cells (EPCs) of a 20-year-old female healthy donor using Sendai virus vector encoding Yamanaka factors OCT3/4, SOX2, c-MYC, and KLF4. The established hiPSCs showed a standard morphology and expression of typical undifferentiated stem cell markers, a normal karyotype (46, XX), and demonstrated potential for differentiation in vitro. Furthermore, they were successfully differentiated into cardiomyocytes that expressed cardiomyocyte-specific markers. The iPSC line and iPSC-derived cardiomyocytes will provide new avenues for future drug testing/development and personalized cell therapy for cardiovascular diseases (CVDs)., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Author(s). Published by Elsevier B.V. All rights reserved.)

Techniques allowing the long-term culture of the burst-forming unit of erythroid (BFU-E) progenitor cells are essential for understanding erythropoiesis. Here, we present a protocol for sorting mouse BFU-E cells and culturing them in a medium that promotes BFU-E cell expansion. We describe steps for isolating BFU-E cells from mouse fetal livers by combining magnetic microbeads with flow cytometry and culturing BFU-E cells with a specific expansion media. This approach can enhance the production of BFU-E cells. For complete details on the use and execution of this protocol, please refer to Li et al.. 1 ., Competing Interests: Declaration of interests We have a Chinese patent pending review (2023105116380)., (Copyright © 2023 The Authors. Published by Elsevier Inc. All rights reserved.)

Mean values of hematological parameters are currently used in the clinical laboratory settings to characterize red blood cell properties. Those include red blood cell indices, osmotic fragility test, eosin 5-maleimide (EMA) test, and deformability assessment using ektacytometry to name a few. Diagnosis of hereditary red blood cell disorders is complemented by identification of mutations in distinct genes that are recognized “molecular causes of disease.” The power of these measurements is clinically well-established. However, the evidence is growing that the available information is not enough to understand the determinants of severity of diseases and heterogeneity in manifestation of pathologies such as hereditary hemolytic anemias. This review focuses on an alternative approach to assess red blood cell properties based on heterogeneity of red blood cells and characterization of fractions of cells with similar properties such as density, hydration, membrane loss, redox state, Ca2+ levels, and morphology. Methodological approaches to detect variance of red blood cell properties will be presented. Causes of red blood cell heterogeneity include cell age, environmental stress as well as shear and metabolic stress, and multiple other factors. Heterogeneity of red blood cell properties is also promoted by pathological conditions that are not limited to the red blood cells disorders, but inflammatory state, metabolic diseases and cancer. Therapeutic interventions such as splenectomy and transfusion as well as drug administration also impact the variance in red blood cell properties. Based on the overview of the studies in this area, the possible applications of heterogeneity in red blood cell properties as prognostic and diagnostic marker commenting on the power and selectivity of such markers are discussed.

Mean values of hematological parameters are currently used in the clinical laboratory settings to characterize red blood cell properties. Those include red blood cell indices, osmotic fragility test, eosin 5-maleimide (EMA) test, and deformability assessment using ektacytometry to name a few. Diagnosis of hereditary red blood cell disorders is complemented by identification of mutations in distinct genes that are recognized "molecular causes of disease." The power of these measurements is clinically well-established. However, the evidence is growing that the available information is not enough to understand the determinants of severity of diseases and heterogeneity in manifestation of pathologies such as hereditary hemolytic anemias. This review focuses on an alternative approach to assess red blood cell properties based on heterogeneity of red blood cells and characterization of fractions of cells with similar properties such as density, hydration, membrane loss, redox state, Ca2+ levels, and morphology. Methodological approaches to detect variance of red blood cell properties will be presented. Causes of red blood cell heterogeneity include cell age, environmental stress as well as shear and metabolic stress, and multiple other factors. Heterogeneity of red blood cell properties is also promoted by pathological conditions that are not limited to the red blood cells disorders, but inflammatory state, metabolic diseases and cancer. Therapeutic interventions such as splenectomy and transfusion as well as drug administration also impact the variance in red blood cell properties. Based on the overview of the studies in this area, the possible applications of heterogeneity in red blood cell properties as prognostic and diagnostic marker commenting on the power and selectivity of such markers are discussed. [ABSTRACT FROM AUTHOR]

Cellular iron uptake in most tissues occurs via endocytosis of diferric transferrin (Tf) bound to the transferrin receptor (TfR). Recently, a second transferrin receptor, transferrin receptor 2 (TfR2), has been identified and shown to play a critical role in iron metabolism. TfR2 is capable of Tf-mediated iron uptake and mutations in this gene result in a rare form of hereditary hemochromatosis unrelated to the hereditary hemochromatosis protein, HFE. Unlike TfR, TfR2 expression is not controlled by cellular iron concentrations and little information is currently available regarding the role of TfR2 in cellular iron homeostasis. To investigate the relationship between TfR and TfR2, we performed a series of in vivo and in vitro experiments using antibodies generated to each receptor. Western blots demonstrate that TfR2 protein is expressed strongest in erythroid/myeloid cell lines. Metabolic labeling studies indicate that TfR2 protein levels are approximately 20-fold lower than TfR in these cells. TfR and TfR2 have similar cellular localizations in K562 cells and coimmunoprecipitate to only a very limited extent. Western analysis of the receptors under nonreducing conditions reveals that they can form heterodimers.

The BCR/ABL oncogene causes chronic myelogenous leukemia (CML) in humans and a CML-like disease, as well as lymphoid leukemia, in mice. p210 BCR/ABL is an activated tyrosine kinase that phosphorylates itself and several cellular signaling proteins. The autophosphorylation site tyrosine 177 binds the adaptor Grb2 and helps determine the lineage and severity of BCR/ABL disease: Tyr177 mutation (BCR/ABL-Y177F) dramatically impairs myeloid leukemogenesis, while diminishing lymphoid leukemogenesis. The critical signal(s) from Tyr177 has remained unclear. We report that Tyr177 recruits the scaffolding adaptor Gab2 via a Grb2/Gab2 complex. Compared to BCR/ABL-expressing Ba/F3 cells, BCR/ABL-Y177F cells exhibit markedly reduced Gab2 tyrosine phosphorylation and association of phosphatidylinositol-3 kinase (PI3K) and Shp2 with Gab2 and BCR/ABL, and decreased PI3K/Akt and Ras/Erk activation, cell proliferation, and spontaneous migration. Remarkably, bone marrow myeloid progenitors from Gab2 (-/-) mice are resistant to transformation by BCR/ABL, whereas lymphoid transformation is diminished as a consequence of markedly increased apoptosis. BCR/ABL-evoked PI3K/Akt and Ras/Erk activation also are impaired in Gab2 (-/-) primary myeloid and lymphoid cells. Our results identify Gab2 and its associated proteins as key determinants of the lineage and severity of BCR/ABL transformation.

Recombinant human erythropoietin (rHuEPO) is a prevalent treatment for anemia in patients with chronic kidney disease. However, up to 10% of these patients exhibit EPO resistance or hyporesponsiveness, which may be caused by the depletion of erythroid progenitor cells. Thrombopoietin (TPO) has the potential to promote the growth of early progenitor cells and correct the depletion. In this study, we investigate the efficacy and the underlying mechanism of the combination therapy of TPO and EPO to EPO resistance. First, the in vivo studies suggested that intensive EPO treatment induced progenitor cell depletion in the bone marrow, where the depletion was corrected by TPO. Then, colony assays showed that EPO and TPO synergistically enhanced the burst-forming unit-erythroid (BFU-E) production but antagonistically boosted the colony-forming units of megakaryocytes (CFU-MK) production. Also, we found TPO promoted hematopoietic stem and progenitor cells (HSPCs) production, while EPO drove HSPCs toward the erythroid lineage. Additionally, EPO induced more megakaryocytic-erythroid progenitors (MEPs) toward the erythroid output. Model-based simulations indicate the efficacy of this combination therapy for treating EPO-resistant anemia in rats. In conclusion, our study demonstrated the efficacy of combination therapy in addressing EPO-resistant anemia by correcting EPO-induced erythroid progenitor depletion., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Inc. All rights reserved.)

During the recent coronavirus disease 2019 (COVID-19) pandemic several patients with β-thalassemia have been infected by severe acute respiratory syndrome coronavirus (SARS-CoV-2), and most patients were vaccinated against SARS-CoV-2. Recent studies demonstrate an impact of SARS-CoV-2 infection on the hematopoietic system. The main objective of this study was to verify the effects of exposure of erythroid precursor cells (ErPCs) from patients with β-thalassemia to SARS-CoV-2 spike protein (S-protein) and the BNT162b2 vaccine. Erythropoietin (EPO)-cultured ErPCs have been either untreated or treated with S-protein or BNT162b2 vaccine. The employed ErPCs were from a β-thalassemia cellular Biobank developed before the COVID-19 pandemic. The genotypes were β + -IVSI-110/β + -IVSI-110 (one patient),  β 0 39/β + -IVSI-110 (3 patients), and β 0 39/ β 0 39 (2 patients). After treatment with S-protein or BNT162b2 for 5 days, lysates were analyzed by high performance liquid chromatography (HPLC), for hemoglobin production, and isolated RNA was assayed by RT-qPCR, for detection of globin gene expression. The main conclusions of the results obtained are that SARS-CoV-2 S-protein and BNT162b2 vaccine (a) inhibit fetal hemoglobin (HbF) production by β-thalassemic ErPCs and (b) inhibit γ-globin mRNA accumulation. In addition, we have performed in silico studies suggesting a high affinity of S-protein to HbF. Remarkably, the binding interaction energy of fetal hemoglobin to S-protein was comparable with that of angiotensin-converting enzyme 2 (ACE2). Our results are consistent with the hypothesis of a relevant impact of SARS-CoV-2 infection and COVID-19 vaccination on the hematopoietic system., Competing Interests: Conflict of Interest Disclosure The authors do not have any conflicts of interest to declare in relation to this work., (Copyright © 2023 ISEH -- Society for Hematology and Stem Cells. Published by Elsevier Inc. All rights reserved.)

Human erythropoiesis is a complex process leading to the production of 2.5 million red blood cells per second. Following commitment of hematopoietic stem cells to the erythroid lineage, this process can be divided into three distinct stages: erythroid progenitor differentiation, terminal erythropoiesis, and reticulocyte maturation. We recently resolved the heterogeneity of erythroid progenitors into four different subpopulations termed EP1-EP4. Here, we characterized the growth factor(s) responsiveness of these four progenitor populations in terms of proliferation and differentiation. Using mass spectrometry-based proteomics on sorted erythroid progenitors, we quantified the absolute expression of ~5500 proteins from EP1 to EP4. Further functional analyses highlighted dynamic changes in cell cycle in these populations with an acceleration of the cell cycle during erythroid progenitor differentiation. The finding that E2F4 expression was increased from EP1 to EP4 is consistent with the noted changes in cell cycle. Finally, our proteomic data suggest that the protein machinery necessary for both oxidative phosphorylation and glycolysis is present in these progenitor cells. Together, our data provide comprehensive insights into growth factor-dependence of erythroid progenitor proliferation and the proteome of four distinct populations of human erythroid progenitors which will be a useful framework for the study of erythroid disorders., (© 2023 The Authors. American Journal of Hematology published by Wiley Periodicals LLC.)

Induction of fetal hemoglobin (HbF) is highly beneficial for patients carrying β-thalassemia, and novel HbF inducers are highly needed. Here, we describe a new class of promising HbF inducers characterized by an isoxazole chemical skeleton and obtained through modification of two natural molecules, geldanamycin and radicicol. After preliminary biological assays based on benzidine staining and RT-qPCR conducted on human erythroleukemic K562 cells, we employed erythroid precursors cells (ErPCs) isolated from β-thalassemic patients. ErPCs weretreated with appropriate concentrations of isoxazole derivatives. The accumulation of globin mRNAs was studied by RT-qPCR, and hemoglobin production by HPLC. We demonstrated the high efficacy of isozaxoles in inducing HbF. Most of these derivatives displayed an activity similar to that observed using known HbF inducers, such as hydroxyurea (HU) or rapamycin; some of the analyzed compounds were able to induce HbF with more efficiency than HU. All the compounds were active in reducing the excess of free α-globin in treated ErPCs. All the compounds displayed a lack of genotoxicity. These novel isoxazoles deserve further pre-clinical study aimed at verifying whether they are suitable for the development of therapeutic protocols for β-thalassemia.

The process of erythropoiesis is complex and involves the transfer of cells from the yolk sac to the fetal hepar and, ultimately, to the bone marrow during embryonic development. Within the bone marrow, erythroid progenitor cells undergo several stages to generate reticulocytes that enter the bloodstream. Erythropoiesis is regulated by various factors, with erythropoietin (EPO) synthesized by the kidney being the promoting factor and hepcidin synthesized by the hepar inhibiting iron mobilization. Transcription factors, such as GATA and KLF, also play a crucial role in erythropoiesis. Disruption of any of these factors can lead to abnormal erythropoiesis, resulting in red cell excess, red cell deficiency, or abnormal morphological function. This review provides a general description of erythropoiesis, as well as its regulation, highlighting the significance of understanding the process for the diagnosis and treatment of various hematological disorders.

Background: : Erythroid cells play important roles in hemostasis and disease. However, there is still significant knowledge gap regarding stress erythropoiesis., Methods: : Two single-cell RNAseq datasets of erythroid cells on GEO with accession numbers GSE149938 and GSE184916 were obtained. The datasets from two sources, bone marrow and peripheral blood were analyzed using Seurat v4.1.1, and other tools in R. QC metrics were performed, data were normalized and scaled. Principal components that capture the variation of the data were determined. In clustering the cells, KNN graph was constructed and Louvain algorithm was applied to optimize the standard modularity function. Clusters were defined via differential expression of features., Results: We identified 9 different cell types, with a particular cluster representing the stress erythroids. The clusters showed differentially expressed genes as observed from the gene signature plot. The stress erythroid cluster differentially expressed some genes including ALAS2, HEMGN, and GUK1., Conclusion: The erythroid population was found to be heterogeneous, with a distinct sub-cell type constituting the stress erythroids; this may have important implications for our knowledge of steady-state and stress erythropoiesis, and the markers found in this cluster may prove useful for future research into the dynamics of stress erythroid progenitor cell differentiation.