LABORATORY RESEARCH Monocytes-Macrophages that Express α-Smooth Muscle Actin Preserve Primitive Hematopoietic Cells in the Bone Marrow Investigators identified a previously unknown subset of α-smooth muscle actin-positive activated monocytes and macrophages that maintain hematopoietic stem and progenitor cells and protect them from exhaustion during alarm situations. [Nat Immunol] Abstract Recombinant IL-7/HGFβ Efficiently Induces Transplantable Murine Hematopoietic Stem Cells Researchers used the recombinant single-chain form of a naturally occurring murine hybrid cytokine of IL-7 and the β chain of hepatocyte growth factor (rIL-7/HGFβ) in culture to induce large numbers of hematopoietic stem cells (HSCs) from multiple cell sources, including unseparated BM cells, purified HSCs, CD45- BM cells, and embryonic stem cells. [J Clin Invest] Full Article Protein Kinase D-HDAC5 Signaling Regulates Erythropoiesis and Contributes to Erythropoietin Crosstalk with GATA1 Scientists showed that erythropoietin regulates GATA1 through protein kinase D activation, promoting histone deacetylase 5 (HDAC5) dissociation from GATA1, and subsequent GATA1 acetylation. In ex vivo studies, HDAC5-/- progenitors display enhanced entry into and passage through the erythroid lineage, as well as evidence of erythropoietin-independent differentiation. [Blood] Abstract ERG and FLI1 Binding Sites Demarcate Targets for Aberrant Epigenetic Regulation by AML1-ETO in Acute Myeloid Leukemia The results highlight the dual importance of ETS factors in t(8;21) leukemogenesis, both as transcriptional regulators of the oncofusion protein itself as well as proteins that facilitate AML1-ETO binding. [Blood] Abstract Loss of p53 Exacerbates Multiple Myeloma Phenotype by Facilitating the Reprogramming of Hematopoietic Stem/Progenitor Cells to Malignant Plasma Cells by MafB The efficiency of the MafB-induced multiple myeloma reprogramming of normal hematopoietic stem/progenitor cells to terminally differentiated malignant plasma cells is enhanced by p53 deficiency, in analogy to what happens in reprogramming to pluripotency. [Cell Cycle] Abstract Notch Signals Contribute to Preserve the Multipotentiality of Human CD34+CD38-CD45RA-CD90+ Hematopoietic Progenitors by Maintaining T Cell Lineage Differentiation Potential Researchers identified cord blood CD34+CD38-CD45RA-CD90+ cells as one of the earliest targets of Notch in human hematopoiesis. Upon Notch activation CD34+CD38- cells are blocked in their differentiation at the CD34+CD38-CD45RA-CD90+ stage. Notch signaling is required before lymphoid commitment to preserve T-cell potential of CD34+CD38-CD45RA-CD90+ cells. [Exp Hematol] Abstract Identification of the Hemogenic Endothelial Progenitor and Its Direct Precursor in Human Pluripotent Stem Cell Differentiation Cultures The authors showed that human hemogenic endothelium progenitors capable of generating definitive hematopoietic cells can be obtained from human pluripotent stem cells and identified precisely by a VE-cadherin+CD73–CD235a/CD43– phenotype. [Cell Rep] Abstract CLINICAL RESEARCH Targeting p53 In Vivo: A First-in-Human Study with p53-Targeting Compound APR-246 in Refractory Hematologic Malignancies and Prostate Cancer APR-246 is a novel drug that restores transcriptional activity of unfolded wild-type or mutant p53. APR-246 was administered as a two-hour intravenous infusion once per day for four consecutive days in 22 patients with hematologic malignancies and prostate cancer. [J Clin Oncol] Abstract | Press Release Autologous Blood Cell Transplantation versus HLA-Identical Sibling Transplantation for Acute Myeloid Leukemia in First Complete Remission: A Registry Study from the Center for International Blood and Marrow Transplantation Research Investigators compared treatment related mortality, relapse, leukemia-free survival, and overall survival for acute myeloid leukemia in first complete remission receiving myeloablative HLA-matched sibling donor versus autologous peripheral blood. [Haematologica] Abstract | Full Article T-Cell Depleted Stem-Cell Transplantation for Adults with High-Risk Acute Lymphoblastic Leukemia: Long-Term Survival for Patients in 1st Complete Remission with a Decreased Risk of Graft-versus-Host Disease Researchers performed a 56 patient retrospective study to evaluate T-cell depleted allogeneic hematopoietic stem cell transplantation for the treatment of acute lymphoblastic leukemia following myeloablative TBI-based therapy. [Biol Blood Marrow Transplant] Abstract |