LABORATORY RESEARCH Control of Hematopoietic Stem Cell Emergence by Antagonistic Functions of Ribosomal Protein Paralogs The authors demonstrated that despite ubiquitous expression, the ribosomal protein paralogs, Rpl22 and Rpl22-like1 play essential, distinct, and antagonistic roles in hematopoietic development. Knockdown of Rpl22 in zebrafish embryos selectively blocks the development of T lineage progenitors after they have seeded the thymus. [Dev Cell] Abstract | Graphical Abstract | Press Release TGFβ Restores Hematopoietic Homeostasis after Myelosuppressive Chemotherapy Scientists showed that TGFβ signaling is transiently activated in hematopoietic stem and progenitor cells during hematopoietic regeneration. Blockade of TGFβ signaling after chemotherapy accelerates hematopoietic reconstitution and delays the return of cycling hematopoietic stem cells to quiescence. [J Exp Med] Abstract Blockade of Individual Notch Ligands and Receptors Controls Graft-versus-Host Disease Using newly developed humanized antibodies and conditional genetic models, researchers demonstrated that Notch1/Notch2 receptors and the Notch ligands Delta-like1/4 mediate all the effects of Notch signaling in T cells during graft-versus-host disease, with dominant roles for Notch1 and Delta-like4. [J Clin Invest] Full Article | Press Release Erk1 and Erk2 Are Required for Maintenance of Hematopoietic Stem Cells and Adult Hematopoiesis Extracellular signal-regulated kinase 1 (Erk1) and Erk2 play crucial roles in cell survival, proliferation, cell adhesion, migration, and differentiation in many tissues. The authors report that the absence of Erk1 and Erk2 in murine hematopoietic cells leads to bone marrow aplasia, leukopenia, anemia and early lethality. [Blood] Abstract Generation of Multi-Leukemia Antigen-Specific T Cells to Enhance the Graft-versus-Leukemia Effect after Allogeneic Stem Cell Transplant Scientists explored the feasibility of generating tumor associated antigens-specific cytotoxic T lymphocytes from stem cell donors of patients with myeloid leukemia to enhance the graft-versus-leukemia effect after stem cell transplantation. [Leukemia] Abstract Hematopoietic Cells Produce BDNF and Regulate Appetite upon Migration to the Hypothalamus Scientists showed that brain-derived neurotrophic factor-producing hematopoietic cells control appetite and energy balance by migrating to the hypothalamic paraventricular nucleus. These hematopoietic-derived paraventricular nucleus cells produce microglial markers and make direct contacts with neurons in response to feeding status. [Nat Commun] Abstract | Press Release Eupalinilide E Inhibits Erythropoiesis and Promotes the Expansion of Hematopoietic Progenitor Cells The authors performed an unbiased screen using primary human CD34+ hematopoietic stem and progenitor cells (HSPCs) to identify natural products that selectively control their differentiation. They identified a plant-derived natural product, eupalinilide E, that promotes the ex-vivo expansion of HSPCs and hinders the in vitro development of erythrocytes. [ACS Chem Biol] Abstract CLINICAL RESEARCH Transferred WT1-Reactive CD8+ T Cells Can Mediate Antileukemic Activity and Persist in Post-Transplant Patients HLA-A*0201-restricted Wilms tumor antigen 1 (WT1)-specific donor-derived CD8+ cytotoxic T cell clones were administered after hematopoietic cell transplantation to 11 relapsed or high-risk leukemia patients without evidence of on-target toxicity. [Sci Transl Med] Abstract | Press Release Clinical Significance of CD33 Nonsynonymous Single-Nucleotide Polymorphisms in Pediatric Patients with Acute Myeloid Leukemia Treated with Gemtuzumab-Ozogamicin-Containing Chemotherapy Researchers evaluated the clinical implications of CD33 single-nucleotide polymorphisms in pediatric patients with acute myeloid leukemia treated with gemtuzumab-ozogamicin-based therapy. [Clin Cancer Res] Abstract | Press Release |