Competitive transplantation of marrow cells into runx1 mutants revealed a stem cell frequency similar to that of murine marrow cells, which demonstrates the utility of this model for quantifying HSC function. The streamlined approach and robustness of this assay will help broaden its feasibility for future high-throughput transplantation experiments in zebrafish and will enable further novel discoveries in the biology of HSCs.BCR-ABL, an oncogenic fusion gene, plays a central role in the pathogenesis of chronic myeloid leukemia (CML). Oncogenic signaling induces oncogene-induced senescence and senescence-associated secretory phenotype (SASP), which is characterized by enhanced production of various cytokines. BCR-ABL gene transduction confers senescent phenotype in vitro; however, the in vivo relevance of senescence has not been explored in this context. Transplantation of BCR-ABL-expressing hematopoietic stem/progenitor cells caused CML in mice with an increase in bone marrow BCR-ABL+CD41+CD150+ leukemic megakaryocyte-lineage (MgkL) cells, which exhibited enhanced senescence-associated β-galactosidase staining and increased expression of p16 and p21, key molecules that are crucially involved in senescence. Moreover, knockout of p16 and p21 genes reduced both BCR-ABL-induced abnormal megakaryopoiesis and the maintenance of CML cell leukemogenic capacity, as evidenced by attenuated leukemogenic capacity at secondary transplantation. The expression of transforming growth factor-β1 (TGF-β1), a representative SASP molecule, was enhanced in the leukemic MgkL cells, and TGF-β1 inhibition attenuated CML cell leukemogenic capacity both in vitro and in vivo. Furthermore, BCR-ABL-expressing MgkL cells displayed enhanced autophagic activity, and autophagy inhibition reduced bone marrow MgkL cell number and prolonged the survival of CML mice, which had transiently received the tyrosine kinase inhibitor, imatinib, earlier. Thus, BCR-ABL induced the expansion of senescent leukemic MgkL cells, which supported CML leukemogenesis by providing TGF-β1.Factor XI (FXI) is the zymogen of a plasma protease (FXIa) that contributes to hemostasis by activating factor IX (FIX).  https://www.selleckchem.com/products/gw4869.html  In the original cascade model of coagulation, FXI is converted to FXIa by factor XIIa (FXIIa), a component, along with prekallikrein and high-molecular-weight kininogen (HK), of the plasma kallikrein-kinin system (KKS). More recent coagulation models emphasize thrombin as a FXI activator, bypassing the need for FXIIa and the KKS. We took an evolutionary approach to better understand the relationship of FXI to the KKS and thrombin generation. BLAST searches were conducted for FXI, FXII, prekallikrein, and HK using genomes for multiple vertebrate species. The analysis shows the KKS appeared in lobe-finned fish, the ancestors of all land vertebrates. FXI arose later from a duplication of the prekallikrein gene early in mammalian evolution. Features of FXI that facilitate efficient FIX activation are present in all living mammals, including primitive egg-laying monotremes, and may represent enhancement of FIX-activating activity inherent in prekallikrein. FXI activation by thrombin is a more recent acquisition, appearing in placental mammals. These findings suggest FXI activation by FXIIa may be more important to hemostasis in primitive mammals than in placental mammals. FXI activation by thrombin places FXI partially under control of the vitamin K-dependent coagulation mechanism, reducing the importance of the KKS in blood coagulation. This would explain why humans with FXI deficiency have a bleeding abnormality, whereas those lacking components of the KKS do not.Intrabone (IB) injection of umbilical cord blood has been proposed as a potential mechanism to improve transplant engraftment and prevent graft failure. However, conventional IB techniques produce low retention of transplanted cells in the marrow. To overcome this barrier, we developed an optimized IB (OIB) injection method using low-volume, computer-controlled slow infusion that promotes cellular retention in the marrow. Here, we compare engraftment of CD34+ cells transplanted in a myeloablative rhesus macaque (RM) model using the OIB method compared with IV delivery. RM CD34+ cells obtained by apheresis were split equally for transduction with lentiviral vectors encoding either green fluorescent protein or yellow fluorescent protein reporters. Following conditioning, one marked autologous population of CD34+ cells was injected directly IB using the OIB method and the other was injected via slow IV push into the same animal (n = 3). Daily flow cytometry of blood quantified the proportion of engrafting cells deriving from each source. Marrow retention was examined using positron emission tomography/computed tomography imaging of 89Zirconium (89Zr)-oxine-labeled CD34+ cells. CD34+ cells injected via the OIB method were retained in the marrow and engrafted in all 3 animals. However, OIB-transplanted progenitor cells did not engraft any faster than those delivered IV and contributed significantly less to hematopoiesis than IV-delivered cells at all time points. Rigorous testing of our OIB delivery system in a competitive RM myeloablative transplant model showed no engraftment advantage over conventional IV infusion. Given the increased complexity and potential risks of IB vs IV approaches, our data do not support IB transplantation as a strategy to improve hematopoietic engraftment.CD19-directed chimeric antigen receptor (CAR) T-cell treatment has evolved as standard of care (SOC) for multiply relapsed/refractory (R/R) large B-cell lymphoma (LBCL). However, its potential benefit over allogeneic hematopoietic cell transplantation (alloHCT) remains unclear. We compared outcomes with both types of cellular immunotherapy (CI) by intention to treat (ITT). Eligble were all patients with R/R LBCL and institutional tumor board decision recommending SOC CAR T-cell treatment between July 2018 and February 2020, or alloHCT between January 2004 and February 2020. Primary end point was overall survival (OS) from indication. Altogether, 41 and 60 patients for whom CAR T cells and alloHCT were intended, respectively, were included. In both cohorts, virtually all patients had active disease at indication. CI was recommended as part of second-line therapy for 21 alloHCT patients but no CAR T-cell patients. Median OS from indication was 475 days with CAR T cells vs 285 days with alloHCT (P = .88) and 222 days for 39 patients for whom alloHCT beyond second line was recommended (P = .