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Erythroblast enucleation is a unique process during mammalian erythropoiesis, yet its regulatory mechanisms remain largely elusive. Here, we demonstrate the specific regulatory role of the oncogene PIM1, the most highly expressed protein kinase in orthochromatic erythroblasts, in enucleation. Unlike its well-established roles in cancer cell proliferation and survival, knockdown of PIM1 in human erythroid cells does not affect cell growth or apoptosis, but specifically inhibits erythroblast enucleation without altering differentiation. To elucidate the functional conservation of PIM1 in mammalian erythropoiesis, we generate Pim1fl/flEpoRCre mice in which Pim1 is deleted in erythroid cells. Consistent with human erythropoiesis, deletion of Pim1 in mice has no detectable effect on apoptosis or differentiation of erythroid cells, but specifically inhibits erythroblast enucleation. Phosphoproteomic analysis reveals that PIM1 deficiency causes a pronounced decrease in phosphorylation of GTPase-associated proteins involved in actin assembly and vesicle trafficking. Functionally, this perturbation results in an aberrant distribution of F-actin and endocytic vesicles within enucleating cells. These findings reveal the unexpected role of PIM1 in normal erythropoiesis and enhance our understanding of mammalian erythroblast enucleation. The oncogene PIM1 regulates erythroblast enucleation via GTPase-dependent cytoskeletal remodeling and vesicle trafficking, independent of its canonical roles in cell proliferation and apoptosis.

The ten‐eleven translocation family of enzymes (TET1/2/3) promotes DNA demethylation and is essential for hematopoiesis. While the roles of TET1 and TET2 are well‐studied in hematopoiesis, the requirement of TET3 in embryonic and adult hematopoiesis is less investigated. In this study, by characterizing embryonic and adult hematopoiesis in Tie2 +/cre ; Tet3 f/f mice, we have established a requirement for TET3 in regulating hematopoietic stem cells (HSCs; CD150 + CD48 – ). We found that loss of TET3 in the fetal liver and adult bone marrow causes a reduction in the percent of long‐term HSCs (LT‐HSCs; CD150 + CD48 – CD34 – ). This was accompanied by reduced colony forming capacity of TET3‐deficient HSCs in vitro and reduced contribution of HSCs after a competitive bone marrow transplantation in vivo. TET3 deficiency increased DNA methylation at several cell cycle regulator genes leading to their down regulation. This is consistent with, and likely underpins, the reduced number of quiescent HSCs in TET3‐deficient bone marrow. These findings uncover a new role for TET3 in HSC homeostasis during embryonic and adult hematopoiesis.

Myelodysplastic syndrome (MDS) is a malignant hematologic disorder with limited curative options, primarily reliant on hematopoietic stem cell transplantation. Anemia, a prevalent symptom of MDS, has few effective treatment strategies. Realgar, though known for its therapeutic effects on MDS, remains poorly understood in terms of its mechanism of action. In this study, both in vivo and in vitro experiments were conducted using Realgar and its primary active component, As 2 S 2 , to examine their impact on mouse erythroblasts at the single-cell level. Realgar treatment significantly altered the transcriptional profiles and cellular composition of bone marrow in mice, both in vivo and in vitro. Differentially expressed genes in erythroblasts regulated by Realgar were identified, unveiling potential regulatory functions and signaling pathways, such as heme biosynthesis, hemoglobin production, oxygen binding, IL-17 signaling, and MAPK pathways. These findings suggest that Realgar enhances the differentiation of erythroblasts in mouse bone marrow and improves overall blood cell counts. This work offers preliminary insights into Realgar’s mechanisms, expands the understanding of this mineral medicine, and may inform strategies to optimize its therapeutic potential in hematologic diseases. The online version contains supplementary material available at 10.1186/s12935-025-03768-0.