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Objective: Clastogenic injury of the erythroid lineage results in anemia, reticulocytopenia, and transient appearance of micronucleated reticulocytes. However, the micronucleated reticulocyte dose-response in murine models is only linear to 2 Gy total body irradiation and paradoxically decreases at higher exposures, suggesting complex radiation effects on erythroid intermediates. To better understand this phenomenon, we investigated the kinetics and apoptotic response of the erythron to sublethal radiation injury.
Materials And Methods: We analyzed the response to 1 and 4 Gy total body irradiation of erythroid progenitors and precursors using colony assays and imaging flow cytometry, respectively. We also investigated cell cycling and apoptotic gene expression of the steady-state erythron.
Results: After 1 Gy total body irradiation, erythroid progenitors and precursors were partially depleted. In contrast, essentially all bone marrow erythroid progenitors and precursors were lost within 2 days after 4 Gy irradiation. Imaging flow cytometry analysis revealed preferential loss of phenotypic erythroid colony-forming units and proerythroblasts immediately after sublethal irradiation. Furthermore, these populations underwent radiation-induced apoptosis, without changes in steady-state cellular proliferation, at much higher frequencies than later-stage erythroid precursors. Primary erythroid precursor maturation is associated with marked Bcl-xL upregulation and Bax and Bid downregulation.
Conclusions: Micronucleated reticulocyte loss after higher sublethal radiation exposures results from rapid depletion of erythroid progenitors and precursors. This injury reveals that erythroid colony-forming units and proerythroblasts constitute a particularly proapoptotic compartment within the erythron. We conclude that the functional transition of primary proerythroblasts to later-stage erythroid precursors is characterized by a shift from a proapoptotic to an antiapoptotic phenotype.
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http://dx.doi.org/10.1016/j.exphem.2011.01.010 | DOI Listing |
Front Pharmacol
August 2025
Department of Medical Genetics, NHC Key Laboratory of Healthy Birth and Birth Defect Prevention in Western China, The First People's Hospital of Yunnan Province, Kunming, China.
Introduction: β-thalassemia is a genetic hemoglobinopathy characterized by defective β-globin synthesis and ineffective erythropoiesis. Pharmacological induction of fetal hemoglobin (HbF) via γ-globin gene activation represents a promising therapeutic strategy. Total ginsenosides (TG), the principal active constituents of , have shown epigenetic and transcriptional modulatory properties, yet their role in HbF induction remains unexplored.
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September 2025
Institute for Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, Stanford, CA, USA; Department of Medicine, Division of Hematology, Stanford University School of Medicine, Stanford, CA, USA; Cancer Institute, Stanford University School of Medicine, Stanford, CA, USA
Hematopoietic multipotent progenitors (MPPs) regulate blood cell production to meet the evolving demands of an organism. Adult human MPPs remain ill defined, whereas mouse MPPs are well characterized, with distinct immunophenotypes and lineage potencies. Using multi-omic single-cell analyses and functional assays, we identified distinct human MPPs within Lin-CD34+CD38dim/lo adult bone marrow with unique biomolecular and functional properties.
View Article and Find Full Text PDFUnlabelled: Samd14 is crucial for cell signaling and survival in mouse models of acute anemia. Samd14 has an N-terminal actin capping protein (CP) and a C-terminal sterile alpha motif (SAM) to coordinate stem cell factor/Kit and erythropoietin receptor signaling pathways during terminal differentiation of red blood cell precursors. Here we present new findings that Samd14 expression is needed to maintain balanced autophagy in red blood cell precursors following acute anemia.
View Article and Find Full Text PDFUnlabelled: Patients with myelodysplastic syndrome (MDS)/acute myeloid leukemia (AML) with high-risk features including mutations and deletions have poor outcomes due to lack of effective therapies. The atypical chemokine surface receptor C-C motif chemokine receptor-like 2 (CCRL2) is overexpressed in MDS and secondary AML (sAML) compared to healthy hematopoietic cells and we recently found that -mutated MDS/AML and AML with erythroid features express the highest levels of this receptor across MDS/AML subtypes. To illustrate the therapeutic potential of CCRL2 as a therapeutic target, we developed an anti-CCRL2 antibody-drug conjugate (ADC) by conjugating an anti-CCRL2 antibody with the cytotoxic drug pyrrolobenzodiazepine (PBD), which causes DNA double-strand breaks leading to cancer cell death.
View Article and Find Full Text PDFMutations in the RNA splicing factor are among the most common in MDS and are strongly associated with MDS with ring sideroblasts (MDS-RS). While aberrant splicing of terminal erythroid regulators has been implicated in MDS pathogenesis, the impact of mutations on early hematopoietic progenitor function remains unclear. Here, we identify CDK8, a key kinase of the mediator complex involved in transcriptional regulation, as a recurrent mis-spliced target in -mutant MDS.
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