Hematopoietic Stem Cell Induction by Somite-Derived Endothelial Cells Controlled by meox1 Researchers reveal that somite specification of hematopoietic stem cells occurs via the deployment of a specific endothelial precursor population, which arises within a sub-compartment of the zebrafish somite that they have defined as the endotome. [Nature] Abstract | Press Release Dnmt3a and Dnmt3b Have Overlapping and Distinct Functions in Hematopoietic Stem Cells Researchers report conditional inactivation of Dnmt3b in hematopoietic stem cells (HSCs) either alone or combined with Dnmt3a deletion. Combined loss of Dnmt3a and Dnmt3b was synergistic, resulting in enhanced HSC self-renewal and a more severe block in differentiation than in Dnmt3a-null cells, whereas loss of Dnmt3b resulted in a mild phenotype. [Cell Stem Cell] Abstract | Graphical Abstract Tight Regulation of Ubiquitin-Mediated DNA Damage Response by USP3 Preserves the Functional Integrity of Hematopoietic Stem Cells Investigators generated mice deficient for Ub-specific protease 3 (USP3), a histone H2A deubiquitinating enzyme which negatively regulates ubiquitin-dependent DNA damage response signaling. Notably, USP3 deletion increased the levels of histone ubiquitination in adult tissues, reduced the hematopoietic stem cell reserves over time, and shortened animal life span. [J Exp Med] Abstract MEIS1 Regulates Early Erythroid and Megakaryocytic Cell Fate Scientists show that two MEIS1 splice variants are expressed in hematopoietic progenitor cells. Constitutive expression of both directed human hematopoietic progenitors towards a megakaryocyte-erythrocyte progenitor fate. [Haematologica] Abstract | Full Article Longitudinal Analysis of DNA Methylation in CD34+ Hematopoietic Progenitors in Myelodysplastic Syndrome Investigators analyzed global DNA methylation in purified CD34+ hematopoietic progenitors from myelodysplastic syndrome patients undergoing multiple rounds of 5-azacytidine treatment. [Stem Cells Transl Med] Abstract Human Leukocyte Antigen DR Surface Expression on CD14+ Monocytes during Adverse Events after Hematopoietic Stem Cell Transplantation Scientists hypothesized that human leukocyte antigen DR expression might be similarly altered after hematopoietic stem cell transplantation and during post-transplant complications. [Ann Hematol] Abstract CLINICAL RESEARCH Impact of Platelet Transfusion on Toxicity and Mortality after Hematopoietic Progenitor Cell Transplantation A retrospective single-center cohort study was conducted on 522 patients undergoing hematopoietic progenitor cell transplantation. Associations between platelet transfusion events and clinical characteristics with transplant-related outcomes were assessed using univariate and multivariate analysis. [Transfusion] Abstract Sequential Infusion of Donor Derived Dendritic Cells with Donor Lymphocyte Infusion for Relapsed Hematologic Cancers after Allogeneic Hematopoietic Stem Cell Transplantation Donor lymphocyte infusion (DLI) is often given to induce a graft-versus-leukemia effect after allogeneic hematopoietic stem cell transplantation. Researchers conducted a Phase I trial testing the co-infusion of dendritic cells followed by donor lymphocyte infusion. [Am J Hematol] Abstract Effects of Priming with Recombinant Human Granulocyte Colony-Stimulating Factor on Conditioning Regimen for High-Risk Acute Myeloid Leukemia Patients Undergoing HLA-Haploidentical Hematopoietic Stem Cell Transplantation: A Multicenter Randomized Controlled Study in Southwest China In a multicenter randomized controlled trial in southwestern China, 178 high-risk acute myeloid leukemia patients received HLA-haploidentical hematopoietic stem cell transplantation with conditioning regimens involving recombinant human granulocyte colony-stimulating factor (rhG-CSF) or non-rhG-CSF. [Biol Blood Marrow Transplant] Abstract |