bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cotransplantation of human stromal cell progenitors into preimmune fetal sheep results in early appearance of human donor cells in circulation and boosts cell levels in bone marrow at later time points after transplantation
Authors: Almeida-Porada Graça , Porada Christopher D. , Tran Nam , Zanjani Esmail D. 
Published: October 2019

Abstract
Both in utero and postnatal hematopoietic stem cell (HSC) transplantation would benefit from the development of approaches that produce increased levels of engraftment or a reduction in the period of time required for reconstitution. We used the in utero model of human–sheep HSC transplantation to investigate ways of improving engraftment and differentiation of donor cells after transplantation. We hypothesized that providing a more suitable microenvironment in the form of human stromal cell progenitors simultaneously with the transplanted human HSC would result in higher rates of engraftment or differentiation of the human cells in this xenogeneic model. The results presented here demonstrate that the cotransplantation of both autologous and allogeneic human bone marrow-derived stromal cell progenitors resulted in an enhancement of long-term engraftment of human cells in the bone marrow of the chimeric animals and in earlier and higher levels of donor cells in circulation both during gestation and after birth. By using marked stromal cells, we have also demonstrated that injected stromal cells alone engraft and remain functional within the sheep hematopoietic microenvironment. Application of this method to clinical HSC transplantation could potentially lead to increased levels of long-term engraftment, a reduction in the time for hematopoietic reconstitution, and a means of delivery of foreign genes to the hematopoietic system.
Circulating hematopoietic progenitor cells in first trimester fetal blood
Authors: Campagnoli Cesare , Fisk Nicholas , Overton Timothy , Bennett Phillip , Watts Timothy , Roberts Irene 
Published: October 2019

AbstractThe yolk sac and aorto-gonad-mesonephros region are well recognized as the principal sites of hematopoiesis in the developing embryo, and the liver is the principal site of hematopoiesis in the fetus. However, little is known about circulating hematopoietic stem and progenitor cells in early fetal life. We investigated the number and characteristics of circulating progenitors in first trimester blood of 64 human fetuses (median gestational age, 10+4 weeks; range, 7+6-13+6 weeks). CD34+ cells accounted for 5.1 ± 1.0% of CD45+ cells in first trimester blood, which is significantly more than in term cord blood (0.4 ± 0.03%;P = .0015). However, the concentration of CD34+ cells (6.6 ± 2.4 × 104/mL) was similar to that in term cord blood (5.6 ± 3.9 × 104/mL). The total number of progenitors cultured from unsorted mononuclear cells (MNCs) in first trimester blood was 19.2 ± 2.1 × 103/mL, which is similar to that in term cord blood (26.4 ± 5.6 × 103/mL). All lineages were seen: colony-forming unit–GEMM (CFU-GEMM), CFU-GM, BFU-e, BFU-MK, and CFU-MK. Clonogenic assays of CD34+ cells purified from first trimester samples produced mainly two lineages: BFU-e (39.0 ± 9.6 × 103/mL CD34+ cells) and CFU-GEMM (22.6 ± 4.7 × 103/mL CD34+ cells). Short-term liquid culture of first trimester blood MNCs in SCF + IL-3 + Flt-3 (stem cell factor + interleukin-3 + Flt-3) increased, by 7-fold, the numbers of CFU-GEMM and induced a dramatic increase in BFU-e (65.6 ± 12.1–fold). These data show that significant numbers of committed and multipotent progenitors with capacity for expansion circulate in first trimester fetal blood and can be CD34 selected. These cells should be suitable targets for gene transfer and stem cell transplantation and, because fetal hematopoietic progenitors have been demonstrated in the maternal circulation from early gestation, may also be manipulated for noninvasive prenatal diagnosis of major genetic disorders.
Scavenger receptors on liver Kupffer cells mediate the in vivo uptake of oxidatively damaged red blood cells in mice
Authors: Terpstra Valeska , van Berkel Theo J. C. 
Published: October 2019

AbstractIn vitro studies have shown that damaged red cells and apoptotic cells are efficiently phagocytosed by scavenger receptors from macrophages, even under non-opsonizing conditions. Damaged red blood cells are in vivo effectively removed from the blood circulation, but the responsible receptor systems are largely unknown. We used a murine model in which 51Cr-labeled oxidized red blood cells were injected intravenously, and the cellular uptake sites and the potential involvement of scavenger receptors were analyzed. The decay of damaged red cells was rapid (more than 50% removed within 10 minutes after injection), whereas native red cells were not cleared. The main site of uptake of damaged red cells was the liver Kupffer cells, which contained 24% of the injected dose at 10 minutes after injection. The blood decay and liver uptake were inhibited by typical ligands for scavenger receptors, such as polyinosinic acid, liposomes containing phosphatidylserine, oxidized low-density lipoprotein, and fucoidan, but not by polyadenosinic acid or liposomes without phosphatidylserine. Mice lacking scavenger receptors class A type I and II showed no significant decrease in the ability to take up damaged red cells from the circulation. We conclude that Kupffer cells are mainly responsible for the removal of damaged red cells from the blood circulation, a process mediated by polyinosinic acid- and phosphatidylserine-sensitive scavenger receptors, different from scavenger receptor class A type I and II. Our data indicate that scavenger receptors, as pattern-recognizing receptors, play an important role in vivo in the removal of apoptotic, damaged, or other unwanted cells from the blood circulation.
Transgenic expression of granulocyte-macrophage colony-stimulating factor induces the differentiation and activation of a novel dendritic cell population in the lung
Authors: Wang Jun , Snider Denis P. , Hewlett Bryan R. , Lukacs Nick W. , Gauldie Jack , Liang Hong , Xing Zhou 
Published: October 2019

AbstractThe role of granulocyte-macrophage colony-stimulating factor (GM-CSF) in the differentiation of dendritic cells (DCs) during pulmonary viral infection was investigated by using a mouse model of GM-CSF transgene expression established with an adenoviral vector (AdGM-CSF). GM-CSF gene transfer resulted in increased levels of GM-CSF in the lung, which peaked at day 4 and remained increased up to day 19. A striking cellular response composed predominantly of macrophage-like cells was observed in the lung receiving AdGM-CSF but not control vector. By FACS analysis, the majority of these cells were identified at an early time point as macrophages and later as mature/activated myeloid DCs characterized by CD11bbright, CD11cbright, MHC class IIbright, and B7.1bright. In contrast, GM-CSF had a weak effect on a small DC population that was found present in normal lung and was characterized by CD11cbright and CD11blow. By immunohistochemistry staining for MHC II, the majority of activated antigen-presenting cells were localized to the airway epithelium and peribronchial/perivascular areas in the lung. A concurrently enhanced Th1 immune response was observed under these conditions. The number of CD4 and CD8 T cells was markedly increased in the lung expressing GM-CSF, accompanied by increased release of interferon (IFN)γ in the lung. Furthermore, lymphocytes isolated from either lung parenchyma or local draining lymph nodes of these mice but not the control mice released large amounts of IFNγ on adenoviral antigen stimulation in vitro. These findings reveal that GM-CSF promotes the differentiation and activation of a myeloid DC population primarily by acting on macrophages during pulmonary immune responses.
Transcriptional control of the human plasma membranephospholipid scramblase 1 gene is mediated by interferon-α
Authors: Zhou Quansheng , Zhao Ji , Al-Zoghaibi Fahad , Zhou Aimin , Wiedmer Therese , Silverman Robert H. , Sims Peter J. 
Published: October 2019

AbstractInterferons (IFNs) mediate their diverse biologic activities through induction of the expression of multiple genes. Whereas the mode of action of certain of these IFN-regulated genes has been well characterized, most of the molecular and cellular events underlying the constellation of biologic responses to the IFNs remain unresolved. This study showed that the newly identified PLSCR1 gene for phospholipid scramblase, previously implicated in remodeling of plasma membrane phospholipids, is regulated at the transcriptional level by IFN-. Analysis of 5′ flanking genomic sequence in reporter constructs showed that transcriptional control of PLSCR1 was entirely regulated by a single IFN-stimulated response element located in the first exon. A similar induction of PLSCR1 by IFN-2a was also observed in a variety of other human tumor cell lines as well as in human umbilical vein endothelial cells. In these cell lines, the marked IFN-2a–induced increase in PLSCR1 protein expression, ranging as high as 10-fold above basal levels, was not accompanied by increased cell surface exposure of phosphatidylserine, suggesting that remodeling of the cell surface requires both exposure to IFN and a second yet-to-be identified event to stimulate plasma membrane phospholipid scramblase activity and to mobilize phosphatidylserine to the cell surface.
Adenoviral vector–mediated gene transfer to primitive human hematopoietic progenitor cells: assessment of transduction and toxicity in long-term culture
Authors: MacKenzie Karen L. , Hackett Neil R. , Crystal Ronald G. , Moore Malcolm A. S. 
Published: October 2019

Abstract
Adenoviral gene transfer to primitive hematopoietic progenitor cells (HPCs) would be useful in gene therapy applications where transient, high-level transgene expression is required. In the present investigations, we have used an adenoviral vector expressing the green fluorescent protein (AdGFP) to quantify transduction of primitive HPCs and assess adenoviral-associated toxicity in long-term culture. Here we show that a cytokine cocktail protects mass populations of CD34+ cells and primary colony forming unit–cultures (CFU-Cs) from toxicity, enabling transduction of up to 79% of CD34+ cells. Transduction of CFU-Cs and more primitive HPCs was quantified following fluorescence activated cell sorting for green flourescence protein expression. Our results demonstrate transduction of 45% of primary CFU-Cs, 33% of week-5 cobblestone area forming cells (CAFCs), and 18% of week-5 CFU-Cs. However, AdGFP infection inhibited proliferation of more primitive cells. Although there was no apparent quantitative change in week-5 CAFCs, the clonogenic capacity of week-5 AdGFP-infected cells was reduced by 40% (P &lt; .01) when compared with mock-infected cells. Adenoviral toxicity specifically affected the transduced subset of primitive HPCs. Transduction of primitive cells is therefore probably underestimated by week-5 CFU-Cs and more accurately indicated by week-5 CAFCs. These studies provide the first functional and quantitative evidence of adenoviral transduction of primitive HPCs. However, further investigations will be necessary to overcome adenoviral toxicity toward primitive HPCs before adenoviral vectors can be considered a safe option for gene therapy.
CD9 expression enhances the susceptibility of myeloma cell lines to cell-mediated cytolysis
Authors: Shallal Suhair , Kornbluth Jacki 
Published: October 2019

AbstractMyeloma tumor cells, both freshly excised and cultured, are extremely resistant to cell-mediated cytolysis. As evidence suggests that B-cell susceptibility to lysis is dependent upon its state of differentiation and activation, we tested the ability of a variety of B-cell proliferation and differentiation agents, including pokeweed mitogen (PWM), to enhance the sensitivity of myeloma cells to cell-mediated lysis. PWM was found to significantly enhance the susceptibility of myeloma cell lines and freshly isolated myeloma cells to interleukin-2 (IL-2)–activated cell-mediated cytolysis. This effect was seen with the use of both IL-2–stimulated natural killer (NK) cells and T cells as effectors. The enhanced sensitivity of myeloma cells to cytolysis correlated with an increase in their cell surface expression of CD9, a pre-B cell marker and member of the transmembrane 4 superfamily. Incubation of PWM-stimulated myeloma cells with either monoclonal antibodies or antisense oligonucleotides directed against CD9 abrogated the effect of PWM. In order to determine whether there was a direct relationship between the expression of CD9 and enhanced sensitivity to cytolysis, myeloma cell lines that lacked CD9 expression were transfected with the CD9 gene. The level of cell surface CD9 expression correlates with enhanced susceptibility to lysis. Therefore, CD9 appears to be an important component in enhancing the sensitivity of myeloma cells to lysis mediated by IL-2–activated T cells and NK cells.
Thymic atrophy in murine acute graft-versus-host disease is effected by impaired cell cycle progression of host pro-T and pre-T cells
Authors: Krenger Werner , Rossi Simona , Piali Luca , Holländer Georg A. 
Published: October 2019

AbstractReconstitution of the peripheral T-cell compartment is a critical aspect for the success of bone marrow transplantation and is also dependent on the reestablishment of normal thymic structure and function. Graft-versus-host disease (GVHD), however, exacerbates posttransplant immunodeficiency through a deleterious effect on thymic function. To investigate the mechanisms of GVHD-mediated thymic disease, 2 murine parent→F1transplantation models of acute and chronic GVHD, respectively, were studied. Acute GVHD was associated with changes in thymic architecture and a reduction in cellularity mainly because of the decrease in CD4+CD8+, or double-positive (DP) thymocytes, to less than 15% of values found in mice without GVHD. Simultaneously, mature donor-derived T cells expanded in the confines of the allogeneic thymic microenvironment, leading to local inflammation. Through analysis of in vivo cell proliferation, we demonstrated that the ensuing depletion of DP thymocytes was secondary to a decreased commitment of resident pro-T and pre-T cells to enter the cell cycle. Moreover, DP cells themselves showed altered proliferative capacities in the presence of acute GVHD. These findings suggested that thymic atrophy in acute GVHD is effected by impaired cellular proliferation of immature host thymocytes and that the failure of these cells to enter the cell cycle is dependent on an interferon (IFN)-γ–driven immune response. In contrast, interleukin-4–driven chronic GVHD was not accompanied by a sustained thymic infiltration of donor T cells. Consequently, there was a lack of apparent structural changes, a restricted in situ transcription of inflammatory cytokines, and a virtually unchanged cell cycle progression in vivo.
Increased lipoprotein (a) levels as an independent risk factor for venous thromboembolism
Authors: von Depka Mario , Nowak-Göttl Ulrike , Eisert Roswith , Dieterich Christian , Barthels Monika , Scharrer Inge , Ganser Arnold , Ehrenforth Silke 
Published: October 2019

AbstractElevation of serum lipoprotein (a) (Lp[a]) is a known risk factor predisposing to cardiovascular and cerebrovascular disease. However, little is known about the role of increased Lp(a) in venous thromboembolism (VTE). This study evaluated the role of Lp(a) among a panel of established hereditary thrombogenic defects in patients with VTE. A total of 685 consecutive patients with at least one episode of VTE and 266 sex- and age-matched healthy controls were screened with regard to activated protein C resistance, protein C, protein S, and antithrombin deficiency, elevated serum levels of Lp(a), and the factor V G1691A, MTHFR C677T, and prothrombin G20210A mutations. Elevated Lp(a) levels above 30 mg/dL were found in 20% of all patients, as compared to 7% among healthy controls (P &lt; .001, odds ratio [OR] 3.2, 95% confidence interval [CI], 1.9-5.3). The coexistence of FV G1691A and elevated Lp(a) was significantly more prevalent among patients with VTE than in the control group (7% versus 0.8%; P &lt; .001, OR 9.8, 95% CI, 2.4-40.7). No other established prothrombotic risk factor was found to be significantly combined with increased Lp(a). These data suggest that Lp(a) concentrations greater than 30 mg/dL are a frequent and independent risk factor for VTE. Furthermore, elevated Lp(a) levels might contribute to the penetrance of thromboembolic disease in subjects being affected by other prothrombotic defects, such as FV G1691A mutation.
Immunophenotypic analysis of B cells in PNH: insights into the generation of circulating naive and memory B cells
Authors: Richards Stephen J. , Morgan Gareth J. , Hillmen Peter 
Published: October 2019

AbstractPeripheral blood B cells in patients with paroxysmal nocturnal hemoglobinuria (PNH) comprise variable mixtures of normal B cells produced before the onset of disease and glycosylphosphatidylinositol (GPI)-deficient B cells derived from the PNH hematopoietic stem cell. In a detailed phenotypic analysis of 29 patients with PNH, this study shows consistent phenotypic differences between PNH B cells and residual normal B cells. In the majority of patients with active disease, PNH B cells comprised mainly naive cells with a CD27−IgM+IgDstrong+IgG−phenotype. The proportion of CD27+ memory cells within this compartment was related to disease duration (Spearman [rs] 0.403; P = .030). In PNH patients with predominantly GPI-deficient hematopoiesis, that is, a large granulocyte PNH clone, the residual normal B cells had a predominantly memory (CD27+) phenotype. Furthermore, the majority of these memory B cells were not immunoglobulin (Ig) class switched and had an IgM+IgD+IgG− phenotype. Using PNH as a novel model with which to study B lymphopoiesis, this study provides direct evidence that production of new naive B cells occurs throughout life and that the major population of long-lived memory B cells are IgM+IgD+. Moreover, studies of GPI− B cells in 2 patients in remission from PNH suggest that the life span of a B-cell clone can be more than 24 years.
Differentiation-independent retinoid induction of folate receptor type β, a potential tumor target in myeloid leukemia
Authors: Wang Hui , Zheng Xuan , Behm Frederick G. , Ratnam Manohar 
Published: October 2019

AbstractFolate receptor (FR) type β is expressed in the myelomonocytic lineage, predominantly during neutrophil maturation and in myeloid leukemias. FR-β expression was elevated up to 20-fold by all-trans retinoic acid (ATRA) in KG-1 myeloid leukemia cells in a dose-dependent and reversible manner in the absence of terminal differentiation or cell growth inhibition. ATRA also increased FR-β expression in vitro in myeloid leukemia cells from patient marrow. FR-β was not up-regulated in KG-1 cells treated with phorbol ester, dexamethasone, 1,25-dihydroxy vitamin D3, or transforming growth factor β. ATRA did not induce FR-β expression in receptor negative cells of diverse origin. The ATRA-induced increase in FR-β expression in KG-1 cells occurred at the level of messenger RNA synthesis, and in 293 cells containing a stably integrated FR-β promoter–luciferase reporter construct, ATRA induced expression of the reporter. From experiments using retinoid agonists and antagonists and from cotransfection studies using the FR-β promoter and expression plasmids for the nuclear receptors retinoic acid receptor (RAR)α, RARβ, or RARγ, it appears that the retinoid effect on FR-β expression could be mediated by ligand binding to RARs α, β, or γ, but not to retinoid X receptors. Furthermore, there was apparent cross-talk between RARα and RARγ selective agonists or antagonists, suggesting a common downstream target for RAR isoforms in inducing FR-β expression. Thus, blocks in the RARα-specific pathway of retinoid-induced differentiation may be bypassed during retinoid induction of FR-β expression. The results suggest that to facilitate FR-targeted therapies, retinoids may be used to modulate FR-β expression in myeloid leukemia cells refractory to retinoid differentiation therapy.
Hematopoietic stem cells express Tie-2 receptor in the murine fetal liver
Authors: Hsu Hsiang-Chun , Ema Hideo , Osawa Mitsujiro , Nakamura Yukio , Suda Toshio , Nakauchi Hiromitsu 
Published: October 2019

Abstract
Tie-2 receptor tyrosine kinase expressed in endothelial and hematopoietic cells is believed to play a role in both angiogenesis and hematopoiesis during development of the mouse embryo. This article addressed whether Tie-2 is expressed on fetal liver hematopoietic stem cells (HSCs) at day 14 of gestation. With the use of anti–Tie-2 monoclonal antibody, its expression was detected in approximately 7% of an HSC population of Kit-positive, Sca-1–positive, lineage-negative or -low, and AA4.1-positive (KSLA) cells. These Tie-2–positive KSLA (T+ KSLA) cells represent 0.01% to 0.02% of fetal liver cells. In vitro colony and in vivo competitive repopulation assays were performed for T+ KSLA cells and Tie-2–negative KSLA (T− KSLA) cells. In the presence of stem cell factor, interleukin-3, and erythropoietin, 80% of T+ KSLA cells formed colonies in vitro, compared with 40% of T− KSLA cells. Long-term multilineage repopulating cells were detected in T+ KSLA cells, but not in T− KSLA cells. An in vivo limiting dilution analysis revealed that at least 1 of 8 T+ KSLA cells were such repopulating cells. The successful secondary transplantation initiated with a limited number of T+ KSLA cells suggests that these cells have self-renewal potential. In addition, engraftment of T+ KSLA cells in conditioned newborn mice indicates that these HSCs can be adapted equally by the adult and newborn hematopoietic environments. The data suggest that T+ KSLA cells represent HSCs in the murine fetal liver.
Identification of alloreactive T-cell epitopes on the Rhesus D protein
Authors: Stott Lisa-Marie , Barker Robert N. , Urbaniak Stanislaw J. 
Published: October 2019

AbstractAlthough considerable effort has been devoted to characterizing alloantibodies specific for the Rhesus D (RhD) blood group antigen, virtually nothing is known about the helper response that drives their production. Therefore, the aim of this study was to map alloreactive T-cell epitopes on the RhD protein. Peripheral blood mononuclear cells (PBMCs) were obtained from 22 RhD-negative volunteers in whom anti-D alloantibodies had developed after deliberate immunization or RhD-incompatible pregnancy. The PBMCs were stimulated with a panel of up to 68 overlapping synthetic 15-mer peptides spanning the complete sequence of the RhD protein. One or more peptides elicited proliferative responses by PBMCs from all 22 of the alloimmune volunteers but from only 2 of 8 alloantibody-negative control donors. Proliferation of PBMCs from the alloimmune donors was mediated by major histocompatibility complex class II–restricted T cells expressing the CD45RO marker of previous activation or memory. The number of peptides that induced proliferative responses was unrelated to either the frequency of, or time since, exposure to RhD-positive red blood cells, but it correlated strongly (Rs = 0.75;P &lt; .003) with the level of anti-D antibodies in deliberately immunized donors. The patterns of stimulatory peptides varied among alloimmune volunteers, but particular sequences were commonly recognized, with 4 peptides each eliciting a response in more than 50% of these donors. Identification of such peptides containing dominant alloreactive helper epitopes is the first step in the development of improved or new approaches to preventing hemolytic disease of the newborn that are based on modulating the T-cell response to the RhD protein.