bluuebunny/crossref_metadata_2025 huggingface dataset:
Interleukin-7 (IL-7) Enhances Class Switching to IgE and IgG4 in the Presence of T Cells Via IL-9 and sCD23
Authors: Jeannin Pascale , Delneste Yves , Lecoanet-Henchoz Sybille , Gretener Denise , Bonnefoy Jean-Yves
Published: October 2019

Interleukin-7 (IL-7) is a B-cell growth factor produced by both bone marrow stroma cells and follicular dendritic cells (FDCs) located in primary lymphoid follicles and germinal centers. In this study, we have evaluated the role of IL-7 on human Ig class switching. IL-7 was added to peripheral blood mononuclear cells (PBMCs) or tonsillar B cells in the absence or presence of IL-4 and/or anti-CD40 monoclonal antibody (MoAb). Alone, IL-7 did not affect Ig production by PBMCs or by anti-CD40 MoAb-stimulated B cells. Rather, IL-7 potentiated IL-4–induced IgE and IgG4 production by PBMCs. In parallel, IgG3 production was also enhanced but to a lesser extent, whereas the production of the other isotypes was unaltered. The activity of IL-2, IL-9, or IL-15, which share usage of the common γ chain for signaling, was also assessed. IL-9, like IL-7, potentiated mainly IgE and IgG4 production by IL-4–stimulated PBMCs. IL-15, in contrast, was ineffective, whereas IL-2 enhanced the production of all isotypes. More precisely, IL-7 potentiation of IgE and IgG4 production required the presence of T cells and was accompanied by an increase of the expression of two soluble molecules favoring preferentially IgE and IgG4 synthesis: CD23 (sCD23) and IL-9. Moreover, neutralizing anti-CD23 and anti–IL-9 antibodies partly inhibited the increase of IgE synthesis induced by IL-7. Thus, IL-7 produced locally in the germinal centers by FDCs may interact with T cells and potentiate human IgE and IgG4 switching by favoring IL-9 and sCD23 production.
Acute Bleeding After Bone Marrow Transplantation (BMT)— Incidence and Effect on Survival. A Quantitative Analysis in 1,402 Patients
Authors: Nevo S. , Swan V. , Enger C. , Wojno K.J. , Bitton R. , Shabooti M. , Fuller A.K. , Jones R.J. , Braine H.G. , Vogelsang G.B.
Published: October 2019

Acute bleeding after bone marrow transplantation (BMT) was investigated in 1,402 patients receiving transplants at Johns Hopkins Hospital between January 1, 1986 and June 30, 1995. Bleeding categorization was based on daily scores of intensity used by the blood transfusion service. Moderate and severe episodes were analyzed for bleeding sites. Analysis of the cause of death and the interval of the bleeding episode to outcome endpoints was recorded. Survival estimates were computed for 1,353 BMT patients. The overall incidence was 34%. Minor bleeding was seen in 10.6%, moderate bleeding was seen in 11.3%, and severe bleeding was seen in 12% of all patients. Fourteen percent of patients had moderate or severe gastrointestinal hemorrhage, 6.4% had moderate or severe hemorrhagic cystitis, 2.8% had pulmonary hemorrhage, and 2% had intracranial hemorrhage. Sixty-one percent had 1 bleeding site and 34.4% had more than 1 site. Moderate and severe bleeding was more prevalent in allogeneic (31%) and unrelated patients (62.5%) compared with autologous patients (18.5%). Significant distribution of incidence was found among the different diagnoses, but not by disease status in acute myeloid leukemia, acute lymphoblastic leukemia, chronic myelogenous leukemia, Hodgkin's disease, and non-Hodgkin's lymphoma. Bleeding was associated with significantly reduced survival in allogeneic, autologous, and unrelated BMT and in each disease category except multiple myeloma. Survival was correlated with the bleeding intensity, bleeding site, and the number of sites. Although close temporal association was evident to mortality, bleeding was recorded as the cause of death in only the minority of cases compared with other toxicities after BMT (graft-versus-host disease, infections, and preparative regimen toxicity). Acute bleeding is a common complication after BMT that is profoundly associated with morbidity and mortality. Although bleeding was not a direct cause of death in the majority of cases, it has a potential prognostic implication as a predictor of poor outcome in clinical assessment of patients after BMT.
Apoptotic Signal of Fas Is Not Mediated by Ceramide
Authors: Hsu Shu-Ching , Wu Chia-Cheng , Luh Tien-Yau , Chou Chen-Kung , Han Shau-Hwa , Lai Ming-Zong
Published: October 2019

Ceramide has been suggested as the secondary messenger mediating the apoptotic signal for Fas engagement. By using different inhibitors, we demonstrated here that ceramide is unlikely a mediator of Fas-initiated apoptosis. First, cAMP prevented cell death induced by ceramide but not by Fas. Second, ceramide-triggered, but not Fas-triggered, apoptosis was antagonized by the free radical scavenger C60. Third, the metal chelator pyrrolidinedithiocarbamate suppressed ceramide-initiated DNA fragmentation but had no effect on the Fas-induced cell death. Fourth, the SAPK/ERK kinase dominant negative mutant, which attenuated ceramide-induced cell death, did not prevent Fas-induced apoptosis. Finally, activation of NF-κB inhibited ceramide-induced but not Fas-initiated apoptosis. The fact that many antagonists of ceramide-induced apoptosis could not suppress Fas-mediated cell death clearly indicates that ceramide is not the mediator for Fas-initiated apoptotic signal.
An In Vitro Model of Human Red Blood Cell Production From Hematopoietic Progenitor Cells
Authors: Malik Punam , Fisher Timothy C. , Barsky Lora L.W. , Zeng Licheng , Izadi Parvin , Hiti Alan L. , Weinberg Kenneth I. , Coates Thomas D. , Meiselman Herbert J. , Kohn Donald B.
Published: October 2019

Hemoglobinopathies, such as β-thalassemias and sickle cell anemia (SCA), are among the most common inherited gene defects. Novel models of human erythropoiesis that result in terminally differentiated red blood cells (RBCs) would be able to address the pathophysiological abnormalities in erythrocytes in congenital RBC disorders and to test the potential of reversing these problems by gene therapy. We have developed an in vitro model of production of human RBCs from normal CD34+ hematopoietic progenitor cells, using recombinant growth factors to promote terminal RBC differentiation. Enucleated RBCs were then isolated to a pure population by flow cytometry in sufficient numbers for physiological studies. Morphologically, the RBCs derived in vitro ranged from early polylobulated forms, resembling normal reticulocytes to smooth biconcave discocytes. The hemoglobin pattern in the in vitro-derived RBCs mimicked the in vivo adult or postnatal pattern of β-globin production, with negligible γ-globin synthesis. To test the gene therapy potential using this model, CD34+ cells were genetically marked with a retroviral vector carrying a cell-surface reporter. Gene transfer into CD34+ cells followed by erythroid differentiation resulted in expression of the marker gene on the surface of the enucleated RBC progeny. This model of human erythropoiesis will allow studies on pathophysiology of congenital RBC disorders and test effective therapeutic strategies.
Chronic Lymphocytic Leukemia B Cells Can Express CD40 Ligand and Demonstrate T-Cell Type Costimulatory Capacity
Authors: Schattner Elaine J. , Mascarenhas John , Reyfman Inna , Koshy Mary , Woo Caroline , Friedman Steven M. , Crow Mary K.
Published: October 2019

Chronic lymphocytic leukemia (CLL) is characterized by a clonal expansion of CD5+ B cells in the peripheral blood. Associated immune aberrations include abnormal Th-cell function and pathogenic autoantibodies. Under most circumstances, CLL B cells do not proliferate in culture and express a limited repertoire of surface antigens, including CD19, CD20, CD23, CD27, CD40, and CD70. In this report, we demonstrate that freshly isolated B cells from a subset of CLL cases constitutively express CD40 ligand (CD40L, CD154), a member of the tumor necrosis factor family which is normally expressed by activated CD4+ T cells and mediates T-cell–dependent B-cell proliferation and antibody production. The degree of CD40L expression varied considerably among the CLL cases examined. CD40L was detected in purified CLL B cells by immunofluorescence flow cytometry, by RT-PCR, and by immunoprecipitation. To demonstrate that CD40L in the CLL B cells is functional, we used irradiated CLL cells to stimulate IgG production by target, nonmalignant B cells in coculture. The CLL B cells induced IgG production by normal B cells to a similar degree as did purified T cells in a process which was partially inhibited by monoclonal antibody to CD40L. This is one of the first reports of CD40L expression in a B-cell tumor. The data suggest that CD40L in the tumor cells may be a factor in the generation of pathologic antibodies by normal B cells in some patients with CLL.
Randomized Study on Hydroxyurea Alone Versus Hydroxyurea Combined With Low-Dose Interferon-α2b for Chronic Myeloid Leukemia
Authors:   The Benelux CML Study Group
Published: October 2019

Interferon-α (IFN-α) is considered the standard therapy for chronic myeloid leukemia (CML) patients not suitable for allogeneic stem cell transplantation. From 1987 through 1992, 195 patients in the Benelux with recent untreated CML were randomized between low-dose IFN-α2b (3 MIU, 5 days/wk) or hydroxyurea alone (control group). The white blood cell count had to be kept less than 10 × 109/L in both arms; to this end, the IFN group received additional hydroxyurea, if necessary. The complete hematologic responses at 6 months in the IFN group were 62%, versus 38% in the control group. In the IFN group, a complete hematologic response at 6 months predicted a better survival (P = .001), but such a tendency was also seen in the control group (P = .07). Cytogenetic responses in the IFN group yielded 9% complete responders, 7% partial responders (<35% Ph+), and 24% minor responders (36% to 95% Ph+). The quality of cytogenetic response within the first 24 months was highly predictive for survival (P = .002). Twenty-four patients discontinued IFN-α because of side effects, but they did this at a long median interval of 17.6 months; the remaining patients did not require dose adaptations. Although the hematologic and cytogenetic responses in the IFN group were higher than in the control group, the duration of chronic phase from randomization was not statistically different with 53 and 44 months in the IFN and control group, respectively. Also, no advantage for survival calculated from diagnosis was seen for the IFN group (median, 64 months) compared with the control group (median, 68 months).
CD148 Is a Membrane Protein Tyrosine Phosphatase Present in All Hematopoietic Lineages and Is Involved in Signal Transduction on Lymphocytes
Authors: de la Fuente-Garcı́a Miguel Angel , Nicolás Josep Maria , Freed John H. , Palou Eduard , Thomas Andrew P. , Vilella Ramón , Vives Jordi , Gayá Antoni
Published: October 2019

Evidence is presented showing that a protein tyrosine phosphatase different from CD45 is present on the membrane of human hematopoietic cells. The molecule recognized by the monoclonal antibody 143-41, which has been classified as CD148 in the VI International Workshop on Leukocyte Differentiation Antigens, was immunopurified and sequenced. The sequence obtained from N-terminus as well as from two different CNBr-digested peptides showed a close identity with a previously described tyrosine phosphatase named HPTP-η/DEP-1. CD148 is present on all hematopoietic lineages, being expressed with higher intensity on granulocytes than on monocytes and lymphocytes. Interestingly, whereas it is clearly present on peripheral blood lymphocytes, it is poorly expressed on different lymphoid cell lines of T and B origin. When this protein tyrosine phosphatase was cocrosslinked with CD3, an inhibition of the normally observed calcium mobilization was observed. This inhibition correlates with a decrease in phospholipase C-γ (PLC-γ) phosphorylation and is similar to the one observed with CD45. In addition, it is shown that the crosslinking of the CD148 alone is also able to induce an increase in [Ca2+]i. This increase is abolished in the presence of genistein and by cocrosslinking with CD45. These data, together with the induction of tyrosine phosphorylation on several substrates, including PLC-γ, after CD148 crosslinking, suggest the involvement of a tyrosine kinase-based signaling pathway in this process. In conclusion, the data presented show that CD148 corresponds to a previously described protein tyrosine phosphatase HPTP-η/DEP-1 and that this molecule is involved in signal transduction in lymphocytes.
Retinoic Acid Selectively Inhibits Lipopolysaccharide Induction of Tissue Factor Gene Expression in Human Monocytes
Authors: Oeth Paul , Yao Jin , Fan Sao-Tah , Mackman Nigel
Published: October 2019

Expression of tissue factor (TF) by activated monocytes in several diseases leads to disseminated intravascular coagulation. Lipopolysaccharide (LPS)-induced monocyte TF expression is downregulated by the nuclear hormone all-trans retinoic acid (ATRA). In this study, we examined the mechanism by which ATRA inhibits monocyte TF expression. We show that ATRA selectively inhibited LPS induction of TF expression in human monocytes and monocytic THP-1 cells without affecting LPS induction of tumor necrosis factor-α (TNF-α) and interleukin-8 (IL-8). Inhibition of TF expression occurred at the level of transcription as determined by nuclear run-on. ATRA did not significantly alter the binding or functional activity of the transcription factors c-Fos/c-Jun and c-Rel/p65, which are required for LPS induction of the TF promoter in monocytic cells. In contrast to the ATRA inhibition of the endogenous TF gene, LPS induction of the cloned TF promoter was not inhibited by ATRA in transiently transfected THP-1 cells. Our results demonstrate that ATRA selectively inhibited LPS-induced TF gene transcription in human monocytic cells by a mechanism that does not involve repression of AP-1– or NF-κB–mediated transcription.
Effects of Guanine Nucleotide Depletion on Cell Cycle Progression in Human T Lymphocytes
Authors: Laliberté Josée , Yee Ann , Xiong Yue , Mitchell Beverly S.
Published: October 2019

Depletion of guanine nucleotide pools after inhibition of inosine monophosphate dehydrogenase (IMPDH) potently inhibits DNA synthesis by arresting cells in G1 and has been shown to induce the differentiation of cultured myeloid and erythroid cell lines, as well as chronic granulocytic leukemic cells after blast transformation. Inhibitors of IMPDH are also highly effective as immunosuppressive agents. The mechanism underlying these pleiotropic effects of depletion of guanine nucleotides is unknown. We have examined the effects of mycophenolic acid (MPA), a potent IMPDH inhibitor, on the cell cycle progression of activated normal human T lymphocytes. MPA treatment resulted in the inhibition of pRb phosphorylation and cell entry into S phase. The expression of cyclin D3, a major component of the cyclin-dependent kinase (CDK) activity required for pRb phosphorylation, was completely abrogated by MPA treatment of T cells activated by interleukin-2 (IL-2) and leucoagglutinin (PHA-L), whereas the expression of cyclin D2, CDK6, and CDK4 was more mildly attenuated. The direct kinase activity of a complex immunoprecipitated with anti-CDK6 antibody was also inhibited. In addition, MPA prevented the IL-2–induced elimination of p27Kip1, a CDK inhibitor, and resulted in the retention of high levels of p27Kip1 in IL-2/PHA-L–treated T cells bound to CDK2. These results indicate that inhibition of the de novo synthesis of guanine nucleotides blocks the transition of normal peripheral blood T lymphocytes from G0 to S phase in early- to mid-G1 and that this cell cycle arrest results from inhibition of the induction of cyclin D/CDK6 kinase and the elimination of p27Kip1 inhibitory activity.
Characterization of Nonrandom Chromosomal Gains and Losses in Multiple Myeloma by Comparative Genomic Hybridization
Authors: Cigudosa Juan C. , Rao Pulivarthi H. , Calasanz M. Jose , Odero M. Dolores , Michaeli Joseph , Jhanwar Suresh C. , Chaganti R.S.K.
Published: October 2019

Clonal chromosomal changes in multiple myeloma (MM) and related disorders are not well defined, mainly due to the low in vivo and in vitro mitotic index of plasma cells. This difficulty can be overcome by using comparative genomic hybridization (CGH), a DNA-based technique that gives information about chromosomal copy number changes in tumors. We have performed CGH on 25 cases of MM, 4 cases of monoclonal gammopathy of uncertain significance, and 1 case of Waldenstrom's macroglobulinemia. G-banding analysis of the same group of patients demonstrated clonal chromosomal changes in only 13 (43%), whereas by CGH, the number of cases with clonal chromosomal gains and losses increased to 21 (70%). The most common recurrent changes detected by CGH were gain of chromosome 19 or 19p and complete or partial deletions of chromosome 13. +19, an anomaly that has so far not been detected as primary or recurrent change by G-banding analysis of these tumors, was noted in 2 cases as a unique change. Other recurrent changes included gains of 9q, 11q, 12q, 15q, 17q, and 22q and losses of 6q and 16q. We have been able to narrow the commonly deleted regions on 6q and 13q to bands 6q21 and 13q14-21. Gain of 11q and deletion of 13q, which have previously been associated with poor outcome, can thus be detected by CGH, allowing the use of this technique for prognostic evaluation of patients, without relying on the success of conventional cytogenetic analysis.
Differential Effects of Chondroitin Sulfates A and B on Monocyte and B-Cell Activation: Evidence for B-Cell Activation Via a CD44-Dependent Pathway
Authors: Rachmilewitz Jacob , Tykocinski Mark L.
Published: October 2019

At inflammatory sites, proteoglycans are both secreted by activated mononuclear leukocytes and released as a consequence of extracellular matrix degradation. Chondroitin 4-sulfate proteoglycans constitute the predominant ones produced by activated human monocytes/macrophages. In this study, we show that two chondroitin 4-sulfate forms, CSA and CSB, can activate distinct peripheral blood mononuclear cell types. Whereas CSA activates monocytes (to secrete monokines), CSB activates B-cells (to proliferate). In contrast, the chondroitin 6-sulfate CSC and heparin do not exert these functional effects. We further show that CD44 monoclonal antibodies block CSB-induced B-cell proliferation. These findings point to glycosaminoglycans, and specifically chondroitin 4-sulfates, as a novel class of immunological mediators at inflammatory sites. Furthermore, the data link CD44 to B-cell activation, paralleling the established roles of CD44 in T-cell and monocyte activation.
Intracellular Storage and Regulated Plasma Membrane Expression of Human Complement Receptor Type 1 in Rat Basophil Leukemia Cell Transfectants
Authors: Jost Carolina , Klickstein Lloyd , Wetzler Erica , Kumar Anoopa , Berger Melvin
Published: October 2019

Polymorphonuclear neutrophils (PMN) contain multiple distinct secretory compartments that are sequentially mobilized during cell activation. Complement receptor type 1 (CR1) is a marker for a readily mobilizable secretory vesicle compartment, which can undergo exocytic fusion with the plasma membrane independently of secretion of traditional granule contents. The basis for the formation of these distinct compartments is incompletely understood. Primary and secondary granules are generated directly from the Golgi complex during different stages of development of the cell, obviating the need for sorting signals for proper packaging of their constituents. To determine whether the secretory vesicles are formed in a similar manner, we studied a stable rat basophilic leukemia cell line (RBL-CR1) transfected with a plasmid containing the cDNA of human CR1 driven by a viral promoter. The CR1 was present primarily intracellularly in small vesicles resembling the CR1 storage pools in resting PMN. Activation of RBL-CR1 resulted in translocation of intracellular CR1 to the plasma membrane, with mobilization requirements different from those of the classical RBL granules. Thus, in RBL-CR1, continuously synthesized CR1 is stored and upregulated in much the same way as in PMN. This suggests that differential timing of gene expression is not essential for proper storage of CR1 and that other sorting mechanisms are involved, which can be studied in RBL-transfectants.
Prostaglandin E2 Induces Resistance to Human Immunodeficiency Virus-1 Infection in Monocyte-Derived Macrophages: Downregulation of CCR5 Expression by Cyclic Adenosine Monophosphate
Authors: Thivierge Maryse , Le Gouill Christian , Tremblay Michel J. , Stanková Jana , Rola-Pleszczynski Marek
Published: October 2019

The chemokine receptor CCR5 can function as a coreceptor for human immunodeficiency virus-1 (HIV-1) entry into CD4+ T cells and macrophages, especially during the early stages of HIV-1 infection. The regulation of CCR5 expression may affect not only leukocyte migration, but also infectivity by HIV-1 and, therefore, acquired immunodeficiency syndrome (AIDS) pathogenesis. We report here that agents which increase intracellular concentrations of cyclic adenosine monophosphate (cAMP) rapidly downregulate CCR5 gene expression, with consequent loss of CCR5 expression and function in monocytes/macrophages. Chemotaxis and intracellular Ca2+mobilization in monocytes pretreated with prostaglandin E2or dibutyryl-cAMP for 24 hours were significantly reduced in response to the CCR5 ligand, MIP-1β. Moreover, HIV-1 entry into monocyte-derived macrophages pretreated with dibutyryl-cAMP or prostaglandin E2 was markedly decreased. Our findings suggest that resistance to HIV-1 can be induced by agents which increase cellular levels of cAMP and that this may suggest additional therapeutic strategies to limit infection by HIV-1.
Human Thymocytes Express CCR-3 and Are Activated by Eotaxin
Authors: Franz-Bacon Karin , Dairaghi Daniel J. , Boehme Stefen A. , Sullivan Susan K. , Schall Thomas J. , Conlon Paul J. , Taylor Naomi , Bacon Kevin B.
Published: October 2019

Eotaxin has been characterized as a chemokine involved in eosinophil activation; however, mRNA for this C-C chemokine has been shown to be constitutively expressed in thymus. Immunohistochemical analysis showed a punctate distribution pattern, with eotaxin expression localized mainly in the medulla and in Hassle’s corpuscles. Moreover, the receptor for eotaxin, CCR-3, was detected on thymocytes, with the highest level of expression being on the CD8 single-positive population. Equilibrium binding analyses on unfractionated thymocytes demonstrated specific 125I-eotaxin binding profiles comparable with CCR-3 transfectants. Eotaxin induced cell migration and mobilization of intracellular calcium in all thymocytes except the immature CD4−/CD8− population. Eotaxin also induced the secretion of the chemokines interleukin-8, RANTES, and macrophage inflammatory protein-1β from thymocyte cultures in vitro. These results suggest that eotaxin-induced thymocyte activation may have important physiological implications for lymphocyte mobilization within and from this lymphoid organ.
Interferon γ Induces Upregulation and Activation of Caspases 1, 3, and 8 to Produce Apoptosis in Human Erythroid Progenitor Cells
Authors: Dai Chunhua , Krantz Sanford B.
Published: October 2019

Interferon γ (IFNγ) induces apoptosis in purified human erythroid colony-forming cells (ECFC) and inhibits cell growth. Fas (APO-1; CD95) and Fas ligand (FasL) mediate apoptosis induced by IFNγ, because Fas is significantly upregulated by IFNγ, whereas Fas ligand is constitutively present in the ECFC and neutralization of FasL greatly reduces the apoptosis. Because conversion of caspases from their dormant proenzyme forms to active enzymes has a critical role in transducing a cascade leading to apoptosis, we performed further studies of the expression and activation of caspases in normal human and IFNγ-treated day-6 ECFC to better understand the mechanism of IFNγ action in producing this cell death. RNase protection assays showed that the caspase-1, -2, -6, -8, and -9 mRNAs were upregulated by IFNγ, whereas the caspase-5 and -7 mRNAs were not increased. Western blots showed that FLICE/caspase-8 was upregulated and activated by 24 hours of incubation with IFNγ. FADD was not similarly altered by incubation with IFNγ. Western blots of ICE/caspase-1, which might be required for amplification of the initial FLICE activation signal, showed that pro-ICE expression significantly increased after treatment with IFNγ for 24 hours and cleavage of pro-ICE also increased. CPP32/apopain/caspase-3, responsible for the proteolytic cleavage of poly (ADP) ribose polymerase (PARP), was also studied and treatment of ECFC with IFNγ resulted in an increased concentration of caspase-3 by 24 hours and a clear induction of enzyme activation by 48 hours, which was identified by the appearance of its p17-kD peptide fragment. The cleavage of PARP was demonstrated by an obvious increase of the 89-kD PARP cleavage product, which was observed at almost the same time as caspase-3 activation in the IFNγ-treated cells, whereas untreated ECFC showed little change. Peptide inhibitors of the caspase proteins, DEVD-fmk, DEVD-cho, YVAD-cho, and IETD-fmk, were incubated with the ECFC to obtain further evidence for the involvement of caspases in IFNγ-induced apoptosis. The activation of FLICE/caspase-8 and CPP32/caspase-3 and cleavage of PARP clearly were inhibited, but the reduction of cell growth due to apoptosis, induced by IFNγ, was only partially blocked by the presence of the inhibitors. These results indicate that IFNγ acts on ECFC not only to upregulate Fas, but also to selectively upregulate caspases-1, -3, and -8, which are activated and produce apoptosis, whereas the concentrations of FasL and FADD are not demonstrably changed.
Modulation of Integrin Function in Hematopoietic Progenitor Cells by CD43 Engagement: Possible Involvement of Protein Tyrosine Kinase and Phospholipase C-γ
Authors: Anzai Naoyuki , Gotoh Akihiko , Shibayama Hirohiko , Broxmeyer Hal E.
Published: October 2019

Attachment of cells to extracellular matrix components is critical for the regulation of hematopoiesis. CD43 is a mucin-like transmembrane sialoglycoprotein expressed on the surface of almost all hematopoietic cells. A highly extended structure of extracellular mucin with negative charge may function as a repulsive barrier to hematopoietic cells. However, some investigators have shown that CD43 has proadhesive properties, and engagement of CD43 has been reported to upregulate integrin-mediated cell adhesion in T cells. We found that cross-linking of CD43 with monoclonal antibodies (MoAbs) enhanced integrin 4β1 (very late antigen [VLA]-4) and 5 β1 (VLA-5)-dependent adhesion of human cord blood CD34+ cells to fibronectin. CD34+ CD38hi, but not CD34+CD38−/low cells responded significantly to the stimulus, suggesting that committed, but not stem and more immature progenitors are sensitive to CD43-mediated activation of integrin. To elucidate the molecular mechanism leading to integrin activation, we used the growth factor-dependent cell line MO7e. Cross-linking of CD43 induced tyrosine phosphorylation of several intracellular molecules including the protein tyrosine kinase Syk, the proto-oncogene product Cbl, and phospholipase C (PLC)-γ2 in MO7e cells. Moreover, protein tyrosine kinase inhibitor herbimycin A and PLC inhibitor U73122 both blocked CD43-induced enhancement of adhesion to fibronectin. These results indicate that signals mediated through CD43 may increase integrin affinity to fibronectin via a pathway dependent on protein tyrosine kinase and PLC-γ activation in hematopoietic progenitors.
Additive Effects of Human Recombinant Interleukin-11 and Granulocyte Colony-Stimulating Factor in Experimental Gram-Negative Sepsis
Authors: Opal Steven M. , Jhung Jhung W. , Keith James C. , Goldman Samuel J. , Palardy John E. , Parejo Nicolas A.
Published: October 2019

Recombinant human granulocyte colony-stimulating factor (rhG-CSF) is widely used to promote granulocyte recovery from a variety of pathologic states. Recombinant human interleukin-11 (rhIL-11) has recently become available clinically as a platelet restorative agent after myelosuppressive chemotherapy. Preclinical data has shown that rhIL-11 limits mucosal injury after chemotherapy and attenuates the proinflammatory cytokine response. The potential efficacy of combination therapy with recombinant human forms of rhIL-11 and rhG-CSF was studied in a neutropenic rat model of Pseudomonas aeruginosa sepsis. At the onset of neutropenia, animals were randomly assigned to receive either rhG-CSF at a dose of 200 μg/kg subcutaneously every 24 hours for 7 days; rhIL-11 at 200 μg/kg subcutaneously every 24 hours for 7 days; the combination of both rhG-CSF and rhIL-11; or saline control. Animals were orally colonized with Pseudomonas aeruginosa 12.4.4 and then given a myelosuppressive dose of cyclophosphamide. rhG-CSF resulted in a slight increase in absolute neutrophil counts (ANC), but did not provide a survival advantage (0 of 12, 0% survival) compared with the placebo group (1 of 12 , 8% survival). rhIL-11 was partially protective (4 of 10, 40% survival); the combination of rhG-CSF and rhIL-11 resulted in a survival rate of 80% (16 of 20; P < .001). rhIL-11 alone or in combination with rhG-CSF resulted in preservation of gastrointestinal mucosal integrity (P < .001), lower circulating endotoxin levels (P < .01), and reduced quantitative levels of P. aeruginosa in quantitative organ cultures. These results indicate that the combination of rhIL-11 and rhG-CSF is additive as a treatment strategy in the prevention and treatment of experimental Gram-negative sepsis in immunocompromised animals. This combination may prove to be efficacious in the prevention of severe sepsis in neutropenic patients.
Reversible Expression of CD34 by Murine Hematopoietic Stem Cells
Authors: Sato Takashi , Laver Joseph H. , Ogawa Makio
Published: October 2019

We used a mouse transplantation model to address the recent controversy about CD34 expression by hematopoietic stem cells. Cells from Ly-5.1 C57BL/6 mice were used as donor cells and Ly-5.2 mice were the recipients. The test cells were transplanted together with compromised marrow cells of Ly-5.2 mice. First, we confirmed that the majority of the stem cells with long-term engraftment capabilities of normal adult mice are CD34−. We then observed that, after the injection of 150 mg/kg 5-fluorouracil (5-FU), stem cells may be found in both CD34− and CD34+ cell populations. These results indicated that activated stem cells express CD34. We tested this hypothesis also by using in vitro expansion with interleukin-11 and steel factor of lineage−c-kit+ Sca-1+ CD34− bone marrow cells of normal mice. When the cells expanded for 1 week were separated into CD34− and CD34+ cell populations and tested for their engraftment capabilities, only CD34+ cells were capable of 2 to 5 months of engraftment. Finally, we tested reversion of CD34+ stem cells to CD34− state. We transplanted Ly-5.1 CD34+post–5-FU marrow cells into Ly-5.2 primary recipients and, after the marrow achieved steady state, tested the Ly-5.1 cells of the primary recipients for their engraftment capabilities in Ly-5.2 secondary recipients. The majority of the Ly-5.1 stem cells with long-term engraftment capability were in the CD34− cell fraction, indicating the reversion of CD34+ to CD34−stem cells. These observations clearly demonstrated that CD34 expression reflects the activation state of hematopoietic stem cells and that this is reversible.
Natural history of hereditary spherocytosis during the first year of life
Authors: Delhommeau F. , Cynober T. , Schischmanoff P. O. , Rohrlich P. , Delaunay J. , Mohandas N. , Tchernia G.
Published: October 2019

Although hereditary spherocytosis (HS) is a common disorder of the red cell membrane, its clinical and biologic expression at birth and in early infancy has received little attention. In order to obtain insights into the natural history of HS during infancy, we studied 46 neonates, 39 from families in which 1 of the parents had previously been given a diagnosis of HS and 7 presenting with nonimmune hemolytic anemia and no family history of HS. Of these 46 neonates, 23 were subsequently confirmed to have HS and 23 were found to be healthy. The hematologic and biologic analyses carried out in this cohort of 46 newborns enabled us to develop guidelines for early diagnosis of HS. A careful clinical follow-up of 34 HS patients during the first year of life allowed us to define several important clinical features of HS during this period. Hemoglobin values are usually normal at birth but decrease sharply during the subsequent 20 days, which leads, in many cases, to a transient and severe anemia. The anemia is severe enough to warrant blood transfusions in a large number of infants with HS (26 of 34 in our series). The aggravation of anemia appears to be related to the inability of these infants to mount an appropriate erythropoietic response to anemia and to the development of splenic filtering function. These findings indicate that careful monitoring of infants with HS during the first 6 months of life is important for appropriate clinical management.
High levels of lymphoid expression of enhanced green fluorescent protein in nonhuman primates transplanted with cytokine-mobilized peripheral blood CD34+ cells
Authors: Donahue Robert E. , Wersto Robert P. , Allay James A. , Agricola Brian A. , Metzger Mark E. , Nienhuis Arthur W. , Persons Derek A. , Sorrentino Brian P.
Published: October 2019

We have used a murine retrovirus vector containing an enhanced green fluorescent protein complimentary DNA (EGFP cDNA) to dynamically follow vector-expressing cells in the peripheral blood (PB) of transplanted rhesus macaques. Cytokine mobilized CD34+ cells were transduced with an amphotropic vector that expressed EGFP and a dihydrofolate reductase cDNA under control of the murine stem cell virus promoter. The transduction protocol used the CH-296 recombinant human fibronectin fragment and relatively high concentrations of the flt-3 ligand and stem cell factor. Following transplantation of the transduced cells, up to 55% EGFP-expressing granulocytes were obtained in the peripheral circulation during the early posttransplant period. This level of myeloid marking, however, decreased to 0.1% or lower within 2 weeks. In contrast, EGFP expression in PB lymphocytes rose from 2%-5% shortly following transplantation to 10% or greater by week 5. After 10 weeks, the level of expression in PB lymphocytes continued to remain at 3%-5% as measured by both flow cytometry and Southern blot analysis, and EGFP expression was observed in CD4+, CD8+, CD20+, and CD16/56+ lymphocyte subsets. EGFP expression was only transiently detected in red blood cells and platelets soon after transplantation. Such sustained levels of lymphocyte marking may be therapeutic in a number of human gene therapy applications that require targeting of the lymphoid compartment. The transient appearance of EGFP+ myeloid cells suggests that transduction of a lineage-restricted myeloid progenitor capable of short-term engraftment was obtained with this protocol.
Recombinant human interleukin-11 synergizes with steel factor and interleukin-3 to promote directly the early stages of murine megakaryocyte development in vitro
Authors: Weich Nadine S. , Fitzgerald Michael , Wang Anlai , Calvetti James , Yetz-Aldape Joanne , Neben Steven , Turner Katherine J.
Published: October 2019

The authors studied the role that interleukin (IL)-11 plays during the early stages of megakaryocyte (MK) development by investigating its in vitro effects on cell subpopulations enriched for bone marrow primitive progenitor cells and early and late committed progenitor cells. Progenitor subpopulations were isolated from bone marrow of normal or 5-fluorouracil (5FU)-treated mice and separated by sorting based on the surface antigens Sca-1, c-kit, and CD34. Functional analysis of the cell subpopulations, 5FU Lin−Sca-1+c-kit+ or normal bone marrow (NBM) Lin−Sca-1+c-kit+CD34−cells, indicated that exposure of these cells to recombinant human (rh)IL-11 in combination with steel factor (SF) stimulates the formation of colonies in methylcellulose and their proliferation in single cell-containing liquid cultures. Kinetic studies of MK progenitor generation, in response to SF and rhIL-11, demonstrated that a significant number of the progenitors produced are committed to the MK lineage. RhIL-11 also synergized with both SF and IL-3 to stimulate MK colony growth from NBM Lin−Sca-1+c-kit+ cells (early progenitors) and NBM Lin−Sca-1−c-kit+ cells (committed late progenitors). In the presence of IL-3, NBM, Lin−Sca-1−c-kit+ cells responded more strongly to rhIL-11 than SF. Consistent with these results is the observation that IL-11 receptor  chain mRNA is present in all the progenitor cells from which the MKs are derived. This cell culture and RNA analysis suggest that murine bone marrow primitive progenitor cells and early and late progenitor cells are direct targets of rhIL-11 and that rhIL-11 has the potential to promote megakaryocyte development at several very early stages. (Blood, 2000;95:503-509)
Protein kinase C-α isoform is involved in erythropoietin-induced erythroid differentiation of CD34+ progenitor cells from human bone marrow
Authors: Myklebust June Helen , Smeland Erlend B. , Josefsen Dag , Sioud Mouldy
Published: October 2019

Protein kinase C (PKC) is a family of serine/threonine protein kinases involved in many cellular responses. Although the analysis of PKC activity in many systems has provided crucial insights to its biologic function, the precise role of different isoforms on the differentiation of normal hematopoietic progenitor cells into the various lineages remains to be investigated. The authors have assessed the state of activation and protein expression of PKC isoforms after cytokine stimulation of CD34+ progenitor cells from human bone marrow. Freshly isolated CD34+ cells were found to express PKC-, PKC-β2, and PKC-ɛ, whereas PKC-δ, PKC-γ, and PKC-ζ were not detected. Treatment with erythropoietin (EPO) or with EPO and stem cell factor (SCF) induced a predominantly erythroid differentiation of CD34+ cells that was accompanied by the up-regulation of PKC- and PKC-β2 protein levels (11.8- and 2.5-fold, respectively) compared with cells cultured in medium. Stimulation with EPO also resulted in the nuclear translocation of PKC- and PKC-β2 isoforms. Notably, none of the PKC isoforms tested were detectable in CD34+ cells induced to myeloid differentiation by G-CSF and SCF stimulation. The PKC inhibitors staurosporine and calphostin C prevented EPO-induced erythroid differentiation. Down-regulation of the PKC-, PKC-β2, and PKC-ɛ expression by TPA pretreatment, or the down-regulation of PKC- with a specific ribozyme, also inhibited the EPO-induced erythroid differentiation of CD34+ cells. No effect was seen with PKC-β2–specific ribozymes. Taken together, these findings point to a novel role for the PKC- isoform in mediating EPO-induced erythroid differentiation of the CD34+ progenitor cells from human bone marrow.
CD38 ligation inhibits normal and leukemic myelopoiesis
Authors: Todisco Elisabetta , Suzuki Toshio , Srivannaboon Kleebsabai , Coustan-Smith Elaine , Raimondi Susana C. , Behm Frederick G. , Kitanaka Akira , Campana Dario
Published: October 2019

CD38 is a transmembrane molecule whose expression varies during hematopoietic cell differentiation. We used stroma-supported cultures of human myeloid cells to assess the effects of CD38 ligation on myeloid differentiation. In 8 experiments with CD34+cells purified from normal bone marrow or cord blood, flow cytometry used with antibodies to CD34 and myeloperoxidase (MPO) identified 4 cell populations after 7 days of culture. Addition of anti-CD38 (T16) to the cultures induced a profound reduction of the most mature (CD34−MPO++) cell population, which includes promyelocytes, myelocytes and metamyelocytes; mean (± SD) cell recovery was 12.8% ± 9.8% of that in parallel cultures with an isotype-matched control antibody. The suppressive effect of CD38 ligation on phenotypically more immature normal cells was inconsistent but generally less pronounced. Recovery of CD34++MPO− cells was 63.3% ± 24.4%, recovery of CD34[+/−]MPO− cells was 95.3% ± 35.1%, and recovery of CD34−MPO+cells was 42.0% ± 18.7% of that in control cultures. However, anti-CD38 suppressed recovery of cells obtained from 6 patients with CD38+ acute myeloid leukemia; after 7-day cultures, cell recovery was 25.2% ± 21.7% of that in control cultures. Cell recovery was also reduced by F(ab′)2 or Fab fragments of anti-CD38. CD38 ligation dramatically suppressed recovery of murine 32D myeloid cells transfected with human CD38 and cocultured with stroma (3.8% ± 7.3%; n = 7). CD38 ligation of CD38 + 32D cells also induced cell aggregation, tyrosine kinase activity, and Ca++ influx. We conclude that CD38 mediates signals that culminate in suppression of myeloid cell growth and survival.
Phenotypic correction of Fanconi anemia group C knockout mice
Authors: Gush Kimberly A. , Fu Kai-Ling , Grompe Markus , Walsh Christopher E.
Published: October 2019

Fanconi anemia (FA) is a genetic disorder characterized by bone marrow failure, congenital anomalies, and a predisposition to malignancy. FA cells demonstrate hypersensitivity to DNA cross-linking agents, such as mitomycin C (MMC). Mice with a targeted disruption of the FANCC gene (fancc −/− nullizygous mice) exhibit many of the characteristic features of FA and provide a valuable tool for testing novel therapeutic strategies. We have exploited the inherent hypersensitivity offancc −/− hematopoietic cells to assay for phenotypic correction following transfer of the FANCC complementary DNA (cDNA) into bone marrow cells. Murine fancc −/− bone marrow cells were transduced with the use of retrovirus carrying the humanfancc cDNA and injected into lethally irradiated recipients. Mitomycin C (MMC) dosing, known to induce pancytopenia, was used to challenge the transplanted animals. Phenotypic correction was determined by assessment of peripheral blood counts. Mice that received cells transduced with virus carrying the wild-type gene maintained normal blood counts following MMC administration. All nullizygous control animals receiving MMC exhibited pancytopenia shortly before death. Clonogenic assay and polymerase chain reaction analysis confirmed gene transfer of progenitor cells. These results indicate that selective pressure promotes in vivo enrichment offancc-transduced hematopoietic stem/progenitor cells. In addition, MMC resistance coupled with detection of the transgene in secondary recipients suggests transduction and phenotypic correction of long-term repopulating stem cells.
Apo-transferrin is internalized and routed differently from Fe-transferrin by Caco-2 cells: a confocal microscopy study of vesicular transport in intestinal cells
Authors: Alvarez-Hernandez Xavier , Smith Margaret , Glass Jonathan
Published: October 2019

Caco-2 cells grown as monolayers on porous membranes in bicameral chambers have been used to study the transport of Fe from the apical (lumenal) chamber to the basal (serosal) chamber. The transport of Fe is stimulated by the presence of either apo-transferrin (apo-Tf) or ferri-transferrin (Fe-Tf) in the basal chamber with the stimulation occurring at much lower concentrations of apo-Tf than Fe-Tf. To further explore the involvement of Tf in Fe transport across the basal surface, laser scanning confocal microscopy with 3-dimensional reconstruction of the confocal images was used to visualize the internalization of Texas Red–labeled apo-Tf and Bodipy-labeled Fe-Tf from the basal chamber. These studies show that apo-Tf was readily internalized and routed preferentially to a perinuclear region of the Caco-2 cells while internalized Fe-Tf stayed preferentially below the nuclei. These findings suggest that intestinal cells have a specialized mechanism to recognize and sort apo-Tf.
Arsenic induces apoptosis of multidrug-resistant human myeloid leukemia cells that express Bcr-Abl or overexpress MDR, MRP, Bcl-2, or Bcl-xL
Authors: Perkins Charles , Kim Caryn N. , Fang Guofu , Bhalla Kapil N.
Published: October 2019

We investigated the in vitro growth inhibitory and apoptotic effects of clinically achievable concentrations of As2O3 (0.5 to 2.0 μmol/L) against human myeloid leukemia cells known to be resistant to a number of apoptotic stimuli. These included chronic myelocytic leukemia (CML) blast crisis K562 and HL-60/Bcr-Abl cells, which contain p210 and p185 Bcr-Abl, respectively, and HL-60 cell types that overexpress Bcl-2 (HL-60/Bcl-2), Bcl-xL(HL-60/Bcl-xL), MDR (HL-60/VCR), or MRP (HL-60/AR) protein. The growth-inhibitory IC50 values for As2O3 treatment for 7 days against all these cell types ranged from 0.8 to 1.5 μmol/L. Exposure to 2 μmol/L As2O3 for 7 days induced apoptosis of all cell types, including HL-60/Bcr-Abl and K562 cells. This was associated with the cytosolic accumulation of cyt c and preapoptotic mitochondrial events, such as the loss of inner membrane potential (▵Ψm) and the increase in reactive oxygen species (ROS). Treatment with As2O3 (2 μmol/L) generated the activities of caspases, which produced the cleavage of the BH3 domain containing proapoptotic Bid protein and poly (ADP-ribose) polymerase. Significantly, As2O3-induced apoptosis of HL-60/Bcr-Abl and K562 cells was associated with a decline in Bcr-Abl protein levels, without any significant alterations in the levels of Bcl-xL, Bax, Apaf-1, Fas, and FasL. Although As2O3 treatment caused a marked increase in the expression of the myeloid differentiation marker CD11b, it did not affect Hb levels in HL-60/Bcr-Abl, K562, or HL-60/neo cells. However, in these cells, As2O3 potently induced hyper-acetylation of the histones H3 and H4. These findings characterize As2O3 as a growth inhibiting and apoptosis-inducing agent against a variety of myeloid leukemia cells resistant to multiple apoptotic stimuli.
Cell-specific, activation-dependent regulation of neutrophil CD32A ligand-binding function
Authors: Nagarajan Shanmugam , Venkiteswaran Kala , Anderson Michael , Sayed Umar , Zhu Cheng , Selvaraj Periasamy
Published: October 2019

Neutrophils express 2 low-affinity FcγR, FcγRIIIB (CD16B), and FcγRIIA (CD32A). CD16B is a glycosyl-phosphatidyl inositol-anchored molecule, whereas CD32A is a polypeptide-anchored molecule. These 2 receptors also differ in their signaling. The biological significance of coexpression of 2 FcγRs with distinct membrane anchors and signaling capacities is not clearly understood. Using neutrophils from a CD16B-deficient donor and normal neutrophils treated with anti-CD16 monoclonal antibodies, the authors demonstrated that affinity modulation of CD32A is one of the mechanisms by which neutrophils regulate their FcγR-dependent functions. Neutrophils isolated from a CD16B− donor rosetted poorly with sheep erythrocytes opsonized with rabbit IgG (EA) (12% ± 2% versus 80% ± 6% for control) and were unable to mediate immunophagocytosis. However, activation of CD16B−neutrophils with fMLP, a bacterial chemotactic peptide, increased the CD32A-dependent EA rosetting to 58%. The CD32A-dependent rosetting of fMLP-activated normal neutrophils also increased nearly 5-fold, but there was no increase in CD32A expression. The CD32A-dependent immune complex (IC) binding was also increased in activated neutrophils. This affinity regulation was not observed with CD32A expressed on Chinese hamster ovary cells. These results suggest that in resting neutrophils CD32A is in a low-affinity state and that these cells primarily engage CD16B for IC binding. However, once the neutrophils are activated, the CD32A is converted to a high-affinity state that leads to CD32A-dependent ligand binding and signaling. These results suggest that neutrophils adopt a novel strategy to engage the 2 different FcγR selectively during physiologic and pathologic conditions to carry out their functions efficiently.