bluuebunny/crossref_metadata_2025 huggingface dataset:
The PIG-A Mutation and Absence of Glycosylphosphatidylinositol-Linked Proteins Do Not Confer Resistance to Apoptosis in Paroxysmal Nocturnal Hemoglobinuria
Authors: Ware Russell E. , Nishimura Jun-ichi , Moody M. Anthony , Smith Clay , Rosse Wendell F. , Howard Thad A.
Published: October 2019

Paroxysmal nocturnal hemoglobinuria (PNH) is a clonal stem cell disorder characterized by complement-mediated hemolysis and deficient hematopoiesis. The development of PNH involves an acquired mutation in the X-linked PIG-A gene, which leads to incomplete bioassembly of glycosylphosphatidylinositol (GPI) anchors and absent or reduced surface expression of GPI-linked proteins. The origin and mechanisms by which the PNH clone becomes dominant are not well understood, but recently resistance to apoptosis has been postulated. To test the hypothesis that the PIG-A mutation and absence of GPI-linked surface proteins directly confer resistance to apoptosis, we isolated peripheral granulocytes from 26 patients with PNH and 20 normal controls and measured apoptosis induced by serum starvation. Granulocytes from patients with PNH were relatively resistant to apoptosis (38.8% ± 14.1%) as compared with granulocytes from controls (55.0% ± 12.0%, P < .001). However, this resistance to apoptosis was not related to the dominance of the PNH clone because patients with a low percentage of GPI-deficient granulocytes had a similar rate of apoptosis as those with a high percentage of GPI-deficient granulocytes. Similarly, the resistance to granulocyte apoptosis was not influenced by the degree of neutropenia or a prior history of aplastic anemia. To investigate formally the importance of GPI-linked surface proteins in apoptosis, we introduced the PIG-A cDNA sequence into the JY5 GPI-negative B-lymphoblastoid cell line using two different methods: (1) stable transfection of a plasmid containing PIG-A, and (2) stable transduction of a retroviral vector containing PIG-A. We then measured rates of apoptosis induced either by Fas antibody, serum starvation, or γ-irradiation. With each stimulus, apoptosis of JY5 with stable surface expression of GPI-linked proteins was not statistically different from the parent JY5 cell line or the JY25 (GPI-positive) cell line. Our data confirm that granulocytes from patients with PNH have a relative resistance to apoptosis as compared with normal granulocytes. However, this resistance does not vary with the level of expression of GPI-linked proteins, and stable introduction of PIG-A cDNA with correction of GPI-linked surface expression does not change the rate of apoptosis. Taken together, our data do not support the hypothesis that the PIG-A mutation and absence of GPI-linked surface proteins directly confer resistance to apoptosis in PNH. We conclude that the resistance to apoptosis in PNH is not related to the PIG-A mutation, indicating that other factors must be important in the origin of this phenomenon and the clonal dominance observed in PNH.
Nonobese Diabetic/Severe Combined Immunodeficiency (NOD/SCID) Mouse as a Model System to Study the Engraftment and Mobilization of Human Peripheral Blood Stem Cells
Authors: van der Loo Johannes C.M. , Hanenberg Helmut , Cooper Ryan J. , Luo F.-Y. , Lazaridis Emmanuel N. , Williams David A.
Published: October 2019

Mobilized CD34+ cells from human peripheral blood (PB) are increasingly used for hematopoietic stem-cell transplantation. However, the mechanisms involved in the mobilization of human hematopoietic stem and progenitor cells are largely unknown. To study the mobilization of human progenitor cells in an experimental animal model in response to different treatment regimens, we injected intravenously a total of 92 immunodeficient nonobese diabetic/severe combined immunodeficiency (NOD/SCID) mice with various numbers of granulocyte colony-stimulating factor (G-CSF) –mobilized CD34+ PB cells (ranging from 2 to 50 × 106cells per animal). Engraftment of human cells was detectable for up to 6.5 months after transplantation and, depending on the number of cells injected, reached as high as 96% in the bone marrow (BM), displaying an organ-specific maturation pattern of T- and B-lymphoid and myeloid cells. Among the different mobilization regimens tested, human clonogenic cells could be mobilized from the BM into the PB (P= .019) with a high or low dose of human G-CSF, alone or in combination with human stem-cell factor (SCF), with an average increase of 4.6-fold over control. Therefore, xenotransplantation of human cells in NOD/SCID mice will provide a basis to further study the mechanisms of mobilization and the biology of the mobilized primitive human hematopoietic cell.
Integrins Involved in the Adhesion of Megakaryocytes to Fibronectin and Fibrinogen
Authors: Schick P.K. , Wojenski C.M. , He X. , Walker J. , Marcinkiewicz C. , Niewiarowski S.
Published: October 2019

We studied integrins involved in the adhesion of resting and activated megakaryocytes (MK) to fibronectin (FN) and fibrinogen (FGN). Guinea pig MK were isolated and in some experiments were activated by thrombin. MK adhering to FN or FGN coated on coverslips were quantitated by a computerized image analysis program. The binding of soluble human FN to MK was detected by Western blotting. Anti-integrin antibodies, disintegrins, and cyclic RGD peptides were used to identify integrins involved in the adhesion of MK to FN or FGN. Resting MK adhered to coverslips with immobilized FN. The adhesion of MK to FN was primarily inhibited by an anti-5 antibody and EMF-10, a distintegrin highly specific for 5β1. However, the adhesion of MK to FN was not blocked by agents that inhibit ΙΙbβ3, vβ3 or 4β1. A β1 activating antibody increased the number of MK bound to FN due to the activation of 5β1. The binding of soluble FN was also primarily inhibited by agents that block 5β1. Resting MK did not adhere to FGN. However, MK activated by thrombin did adhere to FGN. This binding was mediated by ΙΙbβ3, because binding was inhibited by bitistatin, a disintegrin, and a cyclic RGD peptide that are known to block this integrin. The binding of thrombin-activated MK to FN was mediated by both 5β1 and ΙΙbβ3 based on the additive effect of agents that inhibit these integrins. The study indicates that resting MK bind to FN but not to FGN and that 5β1 is the major integrin involved in the binding of MK to FN. Activated MK bind to FGN primarily by IIbβ3. However, the binding of activated MK to FN is due to both 5β1 and IIbβ3. The demonstration that 5β1 and that IIbβ3 are involved in MK adhesion indicates that these integrins may have a role in MK maturation and platelet production.

© 1998 by The American Society of Hematology.
Molecular and Serological Examination of the Relationship of Human Herpesvirus 8 to Multiple Myeloma: orf 26 Sequences in Bone Marrow Stroma Are Not Restricted to Myeloma Patients and Other Regions of the Genome Are Not Detected
Authors: Tisdale John F. , Stewart A. Keith , Dickstein Bruce , Little Richard F. , Dubé Ian , Cappe D. , Dunbar Cynthia E. , Brown Kevin E.
Published: October 2019

Human herpesvirus 8 (HHV-8) genomic sequences were recently detected by polymerase chain reaction (PCR) and in situ hybridization in bone marrow stromal cells grown from multiple myeloma (MM) patients, but not in cells from control subjects (Rettig et al, Science 276:1851, 1997). We sought to confirm these observations in our own group of MM patients (n = 30). DNA was extracted from adherent stromal cells grown under varying conditions and assayed for HHV-8 sequence using PCR to amplify the orf 26 (KS330) sequence (Chang et al,Science 266:1865, 1997), as initially reported. Samples from human control subjects (n = 25) were concurrently extracted and analyzed. After 30 cycles of amplification, we did not detect any positive samples. In a more sensitive nested PCR, samples from 18 of 30 (60%) MM patients were positive, at about the limit of detection, but orf 26 sequence was also amplified from 11 of 25 (44%) human control samples. However, PCR amplification from other regions of the viral genome (orf 72 and orf 75) was uniformly negative for all MM and control samples, despite equivalent sensitivity. Additionally, all sera from MM patients were negative for HHV-8 IgG by immunofluorescence. Our data do not support a role of HHV-8 in the etiology of MM but may suggest the presence of a related (KS330-containing) virus in MM patients and in some control subjects.

This is a US government work. There are no restrictions on its use.
Polymorphisms of Platelet Membrane Glycoprotein Ib Associated With Arterial Thrombotic Disease
Authors: Gonzalez-Conejero Rocio , Lozano Maria L. , Rivera Jose , Corral Javier , Iniesta Juan A. , Moraleda Jose M. , Vicente Vicente
Published: October 2019

Platelet membrane glycoprotein Ib (GPIb) is a major receptor for von Willebrand factor and thrombin, which plays a key role in the initial development of thrombi. Two polymorphisms (HPA-2 and VNTR) that affect phenotype have been described in GPIb. The relevance of these polymorphisms to thrombotic disease was investigated by genotypic identification in three case-control studies: 104 case patients with acute cerebrovascular disease (CVD), 101 case patients with acute coronary heart disease (CHD), 95 patients with deep venous thrombosis (DVT), and one control age-, sex-, and race-matched for each case patient. Results show that the C/B genotype of the VNTR and the HPA-2b polymorphisms of GPIb are strongly associated with increased risk of coronary heart disease and cerebral vascular disease but not with deep vein thrombosis. These two polymorphisms of GPIb may represent newly identified risk factors for arterial thrombotic disease, but not for venous thrombosis.

© 1998 by The American Society of Hematology.
A Regulatory Role for Fcγ Receptors CD16 and CD32 in the Development of Murine B Cells
Authors: de Andres Belen , Mueller Allan L. , Verbeek Sjef , Sandor Matyas , Lynch Richard G.
Published: October 2019

Early in development, murine B-lineage progenitor cells express two classes of IgG Fc receptors (FcγR) designated as FcγRII (CD32) and FcγRIII (CD16), but mature B lymphocytes only express FcγRII (CD32), which functions as an inhibitor of B-cell activation when it is induced to associate with mIgM. The functions of CD16 and CD32 on B-lineage precursor cells have not previously been investigated. To search for FcγR functions on developing B-lineage cells, normal murine bone marrow cells were cultured in the presence of 2.4G2, a rat monoclonal antibody that binds to CD16 and CD32, or in the presence of control normal rat IgG, and then the B-lineage compartment was analyzed for effects. Cultures that contained 2.4G2 showed enhanced growth and differentiation of B-lineage cells compared with control cultures. The enhancing effect of 2.4G2 also occurred when fluorescence-activated cell-sorted B-cell precursors (B220+, sIgM−, HSAhigh, FcγR+) from normal bone marrow were cocultured with BMS2, a bone marrow stromal cell line, but not when they were cultured in BMS2-conditioned media. The enhancement of B-lineage development induced by 2.4G2 was CD16-dependent and CD32-dependent, because 2.4G2 did not effect B-lineage growth or differentiation in cultures of bone marrow from mice in which either the gene encoding CD16 or CD32 had been disrupted. Analysis of fresh bone marrow from the CD16 gene-disrupted mice showed normal numbers and distribution of cells within the B-cell compartment, but in CD32 gene-disrupted mice, the B-cell compartment was significantly enlarged. These experiments provide several lines of evidence that the FcγR expressed on murine B-cell precursors can influence their growth and differentiation.

© 1998 by The American Society of Hematology.
DNA Fiber Fluorescence In Situ Hybridization Analysis of Immunoglobulin Class Switching in B-Cell Neoplasia: Aberrant CH Gene Rearrangements in Follicle Center-Cell Lymphoma
Authors: Vaandrager Jan-Willem , Schuuring Ed , Kluin-Nelemans Hanneke C. , Dyer Martin J.S. , Raap Anton K. , Kluin Philip M.
Published: October 2019

Immunoglobulin class switching usually involves deletion of part of the immunoglobulin CH region. By DNA fiber fluorescence in situ hybridization (FISH) with a barcode of probes covering the DH, JH, and CH genes, the configuration of the entire CH region can be visualized on single DNA molecules. Using this technique, we have studied class switching in three types of B-cell neoplasia, mantle-cell lymphoma (MCL), follicular lymphoma (FL) and hairy cell leukemia (HCL), representing B cells in, respectively, pregerminal center, germinal center, and postgerminal center stages of development. In MCL and FL, simultaneous detection of the t(11;14) and t(14;18) breakpoint with probes for the BCL-1 and BCL-2 loci, respectively, allowed differentiation between productive and nonproductive alleles. In none of 10 MCL cases was class switching detected. In 21 HCL, all nonimmunoglobulin M (IgM) cases had class-switch deletion consistent with the expressed isotype on at least one allele. In FL, however, a peculiar pattern of CH rearrangement was observed. In IgM expressing FL, the translocated alleles had switched in 11 of 13 cases, and the nontranslocated allele showed complex rearrangements downstream from the Cμ-Cδ genes in 9 of 13 cases. These downstream rearrangements may reflect tumor-specific deregulation of the class-switch machinery. All seven immunoglobulin G (IgG) expressing FL showed class switching on both alleles. Fiber FISH analysis also showed several polymorphisms. The most frequent one, present on 38% of all analyzed alleles, consisted of an extra Cγ gene or pseudogene in the 3′ cluster.

© 1998 by The American Society of Hematology.
The Relationship of the −5, −8, and −24 Variant Alleles in African Americans to Triosephosphate Isomerase (TPI) Enzyme Activity and to TPI Deficiency
Authors: Schneider Arthur , Forman Linda , Westwood Beryl , Yim Catherine , Lin James , Singh Satinder , Beutler Ernest
Published: October 2019

In 424 African-American and 75 white subjects, we found that the −5 (TPI 592 A→G), −8 (TPI 589 G→A), and −24 (TPI 573 T→G) variants in the triosephosphate isomerase (TPI) gene occurred frequently (41.0%) in the African-American subjects but did not occur in the whites. These data suggest that this set of polymorphisms may turn out to be one of the higher-incidence molecular markers of African lineage, a surprising finding because others had reported that these nucleotide substitutions were restricted to a small subset of African Americans who had been characterized as TPI-deficiency heterozygotes. Additionally, we investigated the relationship of these variants to TPI-enzyme activity. Although the variant substitutions (occurring in three haplotypes: −5 alone, −5 −8, and −5 −8 −24) were associated with moderate reduction in enzyme activity, severe-deficiency heterozygotes could not be identified with certainty, and none of the haplotypes were restricted to subjects with marked reduction of enzyme activity. Three subjects were homozygous for the −5 −8 haplotype, a finding inconsistent with the putative role of this haplotype as the cause of a null variant incompatible with life in homozygotes. Despite these findings, the possibility remains that the −5 −8 or −5 −8 −24 haplotypes may in some instances contribute to compound heterozygosity and clinical TPI deficiency.

© 1998 by The American Society of Hematology.
Tyrosine-Dependent and -Independent Mechanisms of STAT3 Activation by the Human Granulocyte Colony-Stimulating Factor (G-CSF) Receptor Are Differentially Utilized Depending on G-CSF Concentration
Authors: Ward Alister C. , Hermans Mirjam H.A. , Smith Louise , van Aesch Yvette M. , Schelen Anita M. , Antonissen Claudia , Touw Ivo P.
Published: October 2019

The granulocyte colony-stimulating factor receptor (G-CSF-R) activates multiple STAT proteins. Although the membrane-proximal cytoplasmic region of the G-CSF-R is necessary and sufficient for activation of STAT1 and STAT5, activation of STAT3 requires the membrane distal region that contains four tyrosines. Although one of these (Y704) has previously been shown to be involved in STAT3 activation from a truncated G-CSF-R derived from a patient with severe chronic neutropenia (SCN), this tyrosine is not required for STAT3 activation by the full-length G-CSF-R. To investigate possible alternative mechanisms of STAT3 activation, we generated a series of Ba/F3 cell transfectants expressing the wild-type G-CSF-R or mutant receptors that either completely lack tyrosines or retain just one of the four cytoplasmic tyrosines of the G-CSF-R. We show that, at saturating G-CSF concentrations, STAT3 activation from the full-length G-CSF-R is efficiently mediated by the C-terminal domain in a manner independent of receptor tyrosines. In contrast, at low G-CSF concentrations, Y704 and Y744 of the G-CSF-R play a major role in STAT3 activation. Both tyrosine-dependent and -independent mechanisms of STAT3 activation are sensitive to the Jak2 inhibitor AG-490, follow similar kinetics, and lead to transactivation of a STAT3 reporter construct, indicating functional equivalence. STAT3 activation is also impaired, particularly at nonsaturating G-CSF concentrations, in bone marrow cells from mice expressing a truncated G-CSF-R (gcsfr-▵715). These findings suggest that G-CSF–induced STAT3 activation during basal granulopoiesis (low G-CSF) and “emergency” granulopoiesis (high G-CSF) are differentially controlled. In addition, the data establish the importance of the G-CSF-R C-terminus in STAT3 activation in primary cells, which has implications for understanding why truncated G-CSF-R derived from SCN patients are defective in maturation signaling.
Biochemical Characterization and Molecular Cloning of a Novel Endothelial-Specific Sialomucin
Authors: Morgan Suzanne Marie , Samulowitz Ulrike , Darley Liz , Simmons David L. , Vestweber Dietmar
Published: October 2019

We have generated rat monoclonal antibodies (MoAbs) against cell surface antigens of the mouse endothelioma cell line bEND.3. Three antibodies (V.1A7, V.5C7, and V.7C7) were selected, all of which recognize a 75-kD antigen on bEND.3 cells and bind selectively to endothelial cells in cryostat sections of mouse tissues. A cDNA for the antigen was isolated from a bEND.3 pCDM8 expression library by using transient expression in COS-7 cells and immunoselection with the three MoAbs. This cDNA coded for a novel, type I membrane protein of 248 amino acids with an extracellular domain rich in threonine and serine residues (35%). The protein is sensitive to O-sialoglycoprotein endopeptidase, indicating that it belongs to the class of sialomucin-like proteins. Therefore, we suggest the name endomucin. Treatment of isolated endomucin by sialidase and O-glycosidase reduced the apparent molecular weight to 45 kD and abolished binding of all three antibodies, indicating that carbohydrates are directly or indirectly involved in the formation of the antibody epitopes. Immunohistological analysis of all examined mouse tissues showed that endomucin is an endothelial antigen found in venous endothelium as well as in capillaries, but not on arterial endothelium. Interestingly, high endothelial venules of peripheral and mesenteric lymph nodes as well as of Peyers’s patches were negative for staining with the three MoAbs.
The Vascular Endothelial-Cadherin Promoter Directs Endothelial-Specific Expression in Transgenic Mice
Authors: Gory S. , Vernet M. , Laurent M. , Dejana E. , Dalmon J. , Huber P.
Published: October 2019

Vascular endothelial-cadherin (VE-cadherin) is a calcium-dependent adhesive molecule, exclusively and constitutively expressed in endothelial cells. Analysis of the VE-cadherin promoter fused to a reporter gene in bovine aortic endothelial cells showed three major functional regions. The proximal region alone (−139, +24) promoted nonspecific transcription; the addition of the (−289, −140) and (−2226, −1190) domains abolished transcription in fibroblasts while expression in endothelial cells remained unchanged, suggesting that fragments (−2226, +24) and longer contain the full endogenous promoter activity. To study the transcriptional specificity of the promoter region in vivo, we generated transgenic mice carrying the chimeric construct containing the (−2486, +24) region. The promoter directed reporter expression in all examined organs of adult transgenic mice. During embryonic development, transgene expression was detected at the early steps of vasculogenesis. Later, the expression persisted during development of the vascular system and was restricted to the endothelial layer of the vessels. Together, these data provide evidence for specific regulatory regions within the VE-cadherinpromoter. Furthermore, the identification of DNA sequences restricting gene expression to the endothelium has many potential applications for the development of animal models of cardiovascular or angiogenic diseases or for the delivery of therapeutic molecules.
Protein Replacement by Receptor-Mediated Endocytosis Corrects the Sensitivity of Fanconi Anemia Group C Cells to Mitomycin C
Authors: Youssoufian Hagop , Kruyt Frank A.E. , Li Xiaotong
Published: October 2019

Current methods for direct gene transfer into hematopoietic cells are inefficient. Here we show that functional complementation of Fanconi anemia (FA) group C cells by protein replacement can be as efficacious as by transfection with wild-type FAC cDNA. We expressed a chimeric protein (called His-ILFAC) consisting of the mature coding portion of gibbon interleukin-3 (IL-3) and full-length FAC inEscherichia coli. The purified bacterial protein is internalized by hematopoietic cells via IL-3 receptors. The intracellular half-life of His-ILFAC is approximately 60 minutes, which is comparable to that of the transgene-encoded FAC protein. In this cell-culture model His-ILFAC completely corrects the sensitivity of FA group C cells to mitomycin C, but it has no effect on FA cells that belong to complementation groups A and B. We suggest that receptor-mediated endocytosis of cytokine-fusion proteins may be of general use to deliver macromolecules into hematopoietic progenitor cells.
DNA Typing for HLA-A and HLA-B Identifies Disparities Between Patients and Unrelated Donors Matched by HLA-A and HLA-B Serology and HLA-DRB1
Authors: Prasad Vinod K. , Kernan Nancy A. , Heller Glenn , O’Reilly Richard J. , Yang Soo Young
Published: October 2019

High incidences of graft failure and graft-versus-host disease in the recipients of bone marrow transplantations (BMT) from unrelated donors (URD) may reflect the existence of allelic disparities between the patient and the URD despite apparent HLA identity at HLA-A, HLA-B, and HLA-DRB1 loci. To identify the extent and pattern of allelic disparities at HLA-A and HLA-B loci, 128 patients and 484 potential URD were evaluated by DNA typing. DNA typing for HLA-A, HLA-B, and HLA-DRB1 was performed at Memorial Sloan Kettering Cancer Center. HLA-A and HLA-B serotyping on URD was provided by the registries. By original typing (serology for HLA-A and HLA-B; DNA typing for DRB1) 187, 164, and 133 URD were 6/6, 5/6, and 4/6 matches, respectively. Following DNA typing, however, only 52.9% of the originally 6/6 matched URD remained 6/6, while 38.5%, 7.5%, and 1.1% were found to be 5/6, 4/6, and 3/6 matches. The level of disparity was higher in the originally 5/6 (P< .01) and 4/6 (P < .01) matched URD. A higher level of disparity was seen for HLA-B as compared to HLA-A. In addition, a serotype related variation was also noticed. For example, 24.1% of HLA-A2 and 60.1% of HLA-B35 seromatched URD were genotypically disparate, but no disparities were seen for HLA-A1 and HLA-B8. A higher percentage of HLA-A (67.4%) compared with HLA-B (35.4%) serologic homozygous URD remained genotypically homozygous (P = .01). The level of allelic disparity was lower (P < .01 for 6/6; P = .02 for 5/6) if the patient had one of the 15 most common haplotypes (A1B8DR3, A2B7DR15, A3B7DR15, etc) in comparison to the rest of the group. Outcome studies will answer the question whether these disparities are associated with a higher rate of immunological complications seen with URD-BMT.
Secondary Lymphoid-Tissue Chemokine (SLC) Is Chemotactic for Mature Dendritic Cells
Authors: Chan Vivien W.F. , Kothakota Srinivas , Rohan Michael C. , Panganiban-Lustan Lootsee , Gardner Jason P. , Wachowicz Matthew S. , Winter Jill A. , Williams Lewis T.
Published: October 2019

Dendritic cells (DC) take up antigen from the periphery and migrate to the lymphoid organs where they present the processed antigens to T cells. The propensity of DC to migrate changes during DC maturation and is probably dependent on alterations in the expression of chemokine receptors on the surface of DC. Secondary lymphoid tissue chemokine (SLC), a recently discovered chemokine for naı̈ve T cells, is primarily expressed in secondary lymphoid organs and may be important for colocalizing T cells with other cell types important for T-cell activation. We show here that SLC is a potent chemokine for mature DC but does not act on immature DC. SLC also induced calcium mobilization specifically in mature DC. SLC and Epstein-Barr virus–induced molecule 1 ligand chemokine completely cross-desensitized the calcium response of each other, indicating that they share similar signaling pathways in DC. The finding that SLC is a potent chemokine for DC as well as naı̈ve T cells suggests that it plays a role in colocalizing these two cell types leading to cognate T-cell activation.
Engraftment in Nonobese Diabetic Severe Combined Immunodeficient Mice of Human CD34+ Cord Blood Cells After Ex Vivo Expansion: Evidence for the Amplification and Self-Renewal of Repopulating Stem Cells
Authors: Piacibello Wanda , Sanavio Fiorella , Severino Antonella , Danè Alessandra , Gammaitoni Loretta , Fagioli Franca , Perissinotto Eliana , Cavalloni Giuliana , Kollet Orit , Lapidot Tsvee , Aglietta Massimo
Published: October 2019

Understanding the repopulating characteristics of human hematopoietic stem/progenitor cells is crucial for predicting their performance after transplant into patients receiving high-dose radiochemotherapy. We have previously reported that CD34+cord blood (CB) cells can be expanded in vitro for several months in serum containing culture conditions. The use of combinations of recombinant early acting growth factors and the absence of stroma was essential in determining this phenomenon. However, the effect of these manipulations on in vivo repopulating hematopoietic cells is not known. Recently, a new approach has been developed to establish an in vivo model for human primitive hematopoietic precursors by transplanting human hematopoietic cells into sublethally irradiated nonobese diabetic severe combined immunodeficient (NOD/SCID) mice. We have examined here the expansion of cells, CD34+ and CD34+38− subpopulations, colony-forming cells (CFC), long-term culture initiating cells (LTC-IC) and the maintenance or the expansion of SCID-repopulating cells (SRC) during stroma-free suspension cultures of human CD34+ CB cells for up to 12 weeks. Groups of sublethally irradiated NOD/SCID mice were injected with either 35,000, 20,000, and 10,000 unmanipulated CD34+ CB cells, which were cryopreserved at the start of cultures, or the cryopreserved cells expanded from 35,000, 20,000, or 10,000 CD34+ cells for 4, 8, and 12 weeks in the presence of a combination of early acting recombinant growth factors (flt 3/flk2 ligand [FL] + megakaryocyte growth and development factor [MGDF] ± stem cell factor [SCF] ± interleukin-6 [IL-6]). Mice that had been injected with ≥20,000 fresh or cryopreserved uncultured CD34+ cells did not show any sign or showed little engraftment in a limited number of animals. Conversely, cells that had been generated by the same number of initial CD34+ CB cells in 4 to 10 weeks of expansion cultures engrafted the vast majority of NOD/SCID mice. The level of engraftment, well above that usually observed when the same numbers of uncultured cells were injected in the same recipients (even in the presence of irradiated CD34− cells) suggested that primitive hematopoietic cells were maintained for up to 10 weeks of cultures. In addition, dilution experiments suggest that SRC are expanded more than 70-fold after 9 to 10 weeks of expansion. These results support and extend our previous findings that CD34+ CB stem cells (identified as LTC-IC) could indeed be grown and expanded in vitro for an extremely long period of time. Such information may be essential to design efficient stem cell expansion procedures for clinical use.
Characterization of Cell-Associated Plasminogen Activation Catalyzed by Urokinase-Type Plasminogen Activator, but Independent of Urokinase Receptor (uPAR, CD87)
Authors: Longstaff Colin , Merton R. Elizabeth , Fabregas Pere , Felez Jordi
Published: October 2019

The 55-kD urokinase (uPA) receptor (uPAR, CD87) is capable of binding uPA and may be involved in regulating cell-associated plasminogen activation and pericellular proteolysis. While investigating the relationship between uPAR levels and plasmin generation, we found that uPA-catalyzed plasminogen activation is stimulated by cells which do not express uPAR. This uPAR-independent mechanism appears to be at least as effective in vitro as uPAR-dependent stimulation, such that stimulation on the order of 30-fold was observed, resulting from improvements in both apparent kcat and apparent Km. The mechanism depends on simultaneous binding of both uPA and plasminogen to the cell and requires the presence of the amino-terminal fragment (ATF), available in single chain and two chain high-molecular-weight uPA, but not low-molecular-weight uPA. Stimulation was observed in all leukemic cell lines investigated at similar optimum concentrations of 106to 107 cells/mL and may be more general. A mechanism is proposed whereby uPA can associate with binding sites on the cell surface of lower affinity, but higher capacity than uPAR, but these are sufficient to stimulate plasmin generation even at subphysiologic uPA concentrations. This mechanism is likely to operate under conditions commonly used for in vitro studies and may have some significance in vivo.
Prognostic Significance of Anaplastic Lymphoma Kinase (ALK) Protein Expression in Adults With Anaplastic Large Cell Lymphoma
Authors: Gascoyne Randy D. , Aoun Patricia , Wu Daniel , Chhanabhai Mukesh , Skinnider Brian F. , Greiner Timothy C. , Morris Stephan W. , Connors Joseph M. , Vose Julie M. , Viswanatha David S. , Coldman Andrew , Weisenburger Dennis D.
Published: October 2019

Anaplastic large cell lymphoma (ALCL) is an aggressive lymphoma that is frequently associated with the t(2;5)(p23;q35), resulting in expression of a fusion protein, nucleophosmin-anaplastic lymphoma kinase (NPM-ALK), which can be detected by either monoclonal or polyclonal antibodies to the ALK protein. The clinical features of adults with ALCL are incompletely described, and the prognostic factors that are useful for predicting survival remain unclear. This report describes the clinical and laboratory findings in 70 adults with systemic ALCL who were treated with curative intent. We attempted to identify the clinical and pathological factors of prognostic importance, including the International Prognostic Index (IPI), immunophenotype, and expression of the ALK protein. The median age of the patients was 49 years (range, 15 to 75). There were 26 women and 44 men with a median follow-up of 50 months for living patients. Advanced stage was present in 56% and B symptoms were noted in 70% of the patients. Immunostains showed that 46% of the cases had a T-cell phenotype, 36% a null phenotype, and 18% a B-cell phenotype. The expression of ALK protein was found in 51% of the cases. The IPI factors were evenly distributed between the ALK+ and ALK− groups, except that the ALK+ patients were younger (median age, 30 v 61 years; P < .002). The ALK+ cohort included cases with null (44%), T-cell (42%), and B-cell (14%) phenotypes. All 10 cases with cytogenetic or molecular evidence of a t(2;5) were ALK+. The 5-year overall survival (OS) of the entire cohort was 65%. The 5-year OS of the ALK+ and ALK− cases was 79% and 46%, respectively (P < .0003). Analysis of only the T-cell/null cases (n = 57) showed a 5-year OS of 93% for the ALK+ cases and only 37% for the ALK− cases (P < .00001). Univariate analysis of the clinical features showed that age ≤60 years (P < .007), a normal serum lactate dehydrogenase (LDH) (P < .00001), a good performance status (Eastern Cooperative Oncology Group [ECOG] <2) (P< .03), ≤1 extranodal site of disease (P < .012), and an IPI score ≤3 (P < .00001) were associated with improved OS. Although a younger age correlated with ALK positivity, multivariate analysis showed that only a normal serum LDH (P < .00001), an IPI score of ≤3 (P < .0005), and ALK protein expression (P < .005) predicted independently for an improved OS. We conclude that ALCL is a heterogeneous disorder. However, ALK protein expression is an independent predictor of survival and serves as a useful biologic marker of a specific disease entity within the spectrum of ALCL.
Serum Hyaluronan in Patients With Multiple Myeloma: Correlation With Survival and Ig Concentration
Authors: Dahl Inger Marie S. , Turesson Ingemar , Holmberg Erik , Lilja Karin
Published: October 2019

Serum from 386 myeloma patients were analyzed for serum hyaluronan (HYA) at diagnosis. Median age was 68 years (range, 32 to 87 years). The distribution of Ig classes was typical (58% IgG, 21% IgA, 1% IgD, and 20% light chain disease). The patients comprised 58% in stage III, 33% in stage II, and 9% in stage I. The majority (82%) had HYA values within an intermediate range (10 to 120 μg/L), 13% had high values (>120 μg/L), and 5% had abnormally low values (0 to 9 μg/L). For the first time, a patient group with abnormally low HYA serum values is reported. An inverse correlation between survival and HYA serum level was found (P = .015). When tested separately, patients with abnormally low or high HYA values had significantly shorter median survival (21.1 and 19.7 months, respectively) than those with an intermediate HYA concentration (32.6 months; P = .005). Patients with abnormally low or high HYA levels had more advanced disease as judged by staging and biochemical markers. Interestingly, there was an inverse correlation between the HYA value and the M-component concentration in serum. Fifty percent of patients with abnormally low HYA values had IgA myelomas. In conclusion, the serum concentration of HYA may be of prognostic value in selected cases of multiple myeloma. Further studies will be performed to elucidate possible explanations for our findings, especially those related to the HYA cell surface binding proteins.
Identification of Vascular Endothelial Growth Factor (VEGF) Receptor-2 (Flk-1) Promoter/Enhancer Sequences Sufficient for Angioblast and Endothelial Cell-Specific Transcription in Transgenic Mice
Authors: Kappel Andreas , Rönicke Volker , Damert Annette , Flamme Ingo , Risau Werner , Breier Georg
Published: October 2019

The vascular endothelial growth factor (VEGF) receptor-2 (Flk-1) is the first endothelial receptor tyrosine kinase to be expressed in angioblast precursors, and its function is essential for the differentiation of endothelial cells and hematopoietic precursors. We have identified cis-acting regulatory elements of the murineFlk-1 gene that mediate endothelium-specific expression of a LacZ reporter gene in transgenic mice. Sequences within the 5′-flanking region of the Flk-1 gene, in combination with sequences located in the first intron, specifically targeted transgene expression to angioblasts and endothelial cells of transgenic mice. The intronic regulatory sequences functioned as an autonomous endothelium-specific enhancer. Sequences of the 5′-flanking region contributed to a strong, uniform, and reproducible transgene expression and were stimulated by the transcription factor HIF-2. The Flk-1 gene regulatory elements described in this study should allow the elucidation of the molecular mechanisms involved in endothelial cell differentiation and angiogenesis.
Induction and Suppression of Endothelial Cell Apoptosis by Sphingolipids: A Possible In Vitro Model for Cell-Cell Interactions Between Platelets and Endothelial Cells
Authors: Hisano Nobuo , Yatomi Yutaka , Satoh Kaneo , Akimoto Shigeo , Mitsumata Masako , Fujino Masayuki A. , Ozaki Yukio
Published: October 2019

Because sphingosine (Sph) is actively incorporated into platelets and rapidly converted to sphingosine 1-phosphate (Sph-1-P), which is then released extracellularly, it is important to study the effects of Sph and Sph-1-P on endothelial cells from the viewpoint of platelet-endothelial cell interaction. In this study, we found that Sph, as well as ceramide, induces apoptosis in human umbilical vein endothelial cells (HUVECs). In contrast, Sph-1-P acts as a HUVEC survival factor; this bioactive lipid was shown to protect HUVECs from apoptosis induced by the withdrawal of growth factors and to stimulate HUVEC DNA synthesis. In metabolic studies, [3H]Sph, incorporated into HUVECs, was converted to [3H]Cer and further to [3H]sphingomyelin in a time-dependent manner, whereas [3H]Sph-1-P formation from [3H]Sph was weak and transient. These findings in HUVECs are very different from those of platelets, which possess a highly active Sph kinase but lack Sph-1-P lyase. As a result, platelets abundantly store Sph-1-P, whereas HUVECs contain much less Sph-1-P. Finally, HUVECs, in contrast to platelets, failed to release Sph-1-P extracellularly, indicating that HUVECs themselves are not able to supply the survival factor Sph-1-P, but receive it from activated platelets. Our results suggest that platelets may maintain the integrity of endothelial cells by incorporating Sph and releasing Sph-1-P.
Cellular and Subcellular Localization of the Nramp2 Iron Transporter in the Intestinal Brush Border and Regulation by Dietary Iron
Authors: Canonne-Hergaux F. , Gruenheid S. , Ponka P. , Gros P.
Published: October 2019

Genetic studies in animal models of microcytic anemia and biochemical studies of transport have implicated the Nramp2gene in iron transport. Nramp2 generates two alternatively spliced mRNAs that differ at their 3′ untranslated region by the presence or absence of an iron-response element (IRE) and that encode two proteins with distinct carboxy termini. Antisera raised against Nramp2 fusion proteins containing either the carboxy or amino termini of Nramp2 and that can help distinguish between the two Nramp2 protein isoforms (IRE: isoform I; non-IRE: isoform II) were generated. These antibodies were used to identify the cellular and subcellular localization of Nramp2 in normal tissues and to study possible regulation by dietary iron deprivation. Immunoblotting experiments with membrane fractions from intact organs show that Nramp2 is expressed at low levels throughout the small intestine and to a higher extent in kidney. Dietary iron starvation results in a dramatic upregulation of the Nramp2 isoform I in the proximal portion of the duodenum only, whereas expression in the rest of the small intestine and in kidney remains largely unchanged in response to the lack of dietary iron. In proximal duodenum, immunostaining studies of tissue sections show that Nramp2 protein expression is abundant under iron deplete condition and limited to the villi and is absent in the crypts. In the villi, staining is limited to the columnar absorptive epithelium of the mucosa (enterocytes), with no expression in mucus-secreting goblet cells or in the lamina propria. Nramp2 expression is strongest in the apical two thirds of the villi and is very intense at the brush border of the apical pole of the enterocytes, whereas the basolateral membrane of these cells is negative for Nramp2. These results strongly suggest that Nramp2 is indeed responsible for transferrin-independent iron uptake in the duodenum. These findings are discussed in the context of overall mechanisms of iron acquisition by the body.
Expression of 4-Integrin Defines the Earliest Precursor of Hematopoietic Cell Lineage Diverged From Endothelial Cells
Authors: Ogawa Minetaro , Kizumoto Masami , Nishikawa Satomi , Fujimoto Tetsuhiro , Kodama Hiroaki , Nishikawa Shin-Ichi
Published: October 2019

Embryonic stem cells can differentiate in vitro into hematopoietic cells through two intermediate stages; the first being FLK1+ E-cadherin− proximal lateral mesoderm and the second being CD45− VE-cadherin+endothelial cells. To further dissect the CD45−VE-cadherin+ cells, we have examined distribution of 4-integrin on this cell population, because 4-integrin is the molecule expressed on hematopoietic stem cells. During culture of FLK1+ E-cadherin− cells, CD45− VE-cadherin+4-integrin− cells differentiate first, followed by 4-integrin+ cells appearing in both CD45− VE-cadherin+ and CD45−VE-cadherin− cell populations. In the CD45−VE-cadherin+ cell population, 4-integrin+ subset but not 4-integrin− subset had the potential to differentiate to hematopoietic lineage cells, whereas endothelial cell progenitors were present in both subsets. The CD45−VE-cadherin− 4-integrin+ cells also showed hematopoietic potential. Reverse transcription-polymerase chain reaction analyses showed that differential expression of the Gata2 and Myb genes correlated with the potential of the 4-integrin+ cells to give rise to hematopoietic cell differentiation. Hematopoietic CD45−VE-cadherin+ 4-integrin+ cells were also present in the yolk sac and embryonic body proper of 9.5 day postcoitum mouse embryos. Our results suggest that the expression of 4-integrin is a marker of the earliest precursor of hematopoietic cell lineage that was diverged from endothelial progenitors.
Characterization of Two Naturally Occurring Mutations in the Second Epidermal Growth Factor-Like Domain of Factor VII
Authors: Hunault Mathilde , Arbini Arnaldo A. , Carew Josephine A. , Peyvandi Flora , Bauer Kenneth A.
Published: October 2019

We investigated the mechanisms responsible for severe factor VII (FVII) deficiency in homozygous Italian patients with either Gly97Cys or Gln100Arg mutations in the second epidermal growth factor domain of FVII. Transient expression of complementary DNA coding for the mutations in COS-1 cells showed impaired secretion of the mutant molecules. Using stably transfected Chinese hamster ovary (CHO) cells, we performed pulse-chase labeling studies, immunohistochemistry, and experiments with inhibitors of protein degradation, showing that FVII-Cys97 did not accumulate intracellularly but was degraded in a pre-Golgi, nonlysosomal compartment by a cysteine protease. In stably transfected CHO cells expressing FVII-Arg100, the level of intracellular FVII was not increased by several inhibitors of protein degradation, but FVII-Arg100 was retained in the endoplasmic reticulum for a longer period of time than wild-type FVII. FVII-Arg100 had a lower apparent molecular weight than did wild-type FVII under nondenaturing conditions, which is attributable to misfolding due to abnormal disulfide bond formation.
A Reduced Sensitivity for Activated Protein C in the Absence of Factor V Leiden Increases the Risk of Venous Thrombosis
Authors: de Visser Marieke C.H. , Rosendaal Frits R. , Bertina Rogier M.
Published: October 2019

Activated protein C (APC) resistance caused by the factor V Leiden mutation is associated with an increased risk of venous thrombosis. We investigated whether a reduced response to APC, not due to the factor V point mutation, is also a risk factor for venous thrombosis. For this analysis, we used the Leiden Thrombophilia Study (LETS), a case-control study for venous thrombosis including 474 patients with a first deep-vein thrombosis and 474 age- and sex-matched controls. All carriers of the factor V Leiden mutation were excluded. A dose-response relationship was observed between the sensitivity for APC and the risk of thrombosis: the lower the normalized APC sensitivity ratio, the higher the associated risk. The risk for the lowest quartile of normalized APC-SR (<0.92), which included 16.5% of the healthy controls, compared with the highest quartile (normalized APC-SR > 1.05) was greater than fourfold increased (OR = 4.4; 95% confidence interval, 2.9 to 6.6). We adjusted for VIII:C levels, which appeared to affect our APC resistance test. The adjusted (age, sex, FVIII:C) odds ratio for the lowest quartile was 2.5 (95% confidence interval, 1.5 to 4.2). So, after adjustment for factor VIII levels, a reduced response to APC remained a risk factor. Our results show that a reduced sensitivity for APC, not caused by the factor V Leiden mutation, is a risk factor for venous thrombosis.
Interleukin-4 (IL-4) and IL-13 Enhance the Effect of IL-1β on Production of IL-1 Receptor Antagonist by Human Primary Hepatocytes and Hepatoma HepG2 Cells: Differential Effect on C-Reactive Protein Production
Authors: Gabay Cem , Porter Brandon , Guenette Denis , Billir Bahri , Arend William P.
Published: October 2019

Interleukin-1 receptor antagonist (IL-1Ra) is produced by hepatocytes with characteristics of an acute-phase protein. To examine the role of IL-4 and IL-13 in production of IL-1Ra, human primary hepatocytes and HepG2 human hepatoma cells were cultured in the presence of IL-4 or IL-13 in combination with IL-1β and/or IL-6. The results indicated that both IL-4 and IL-13 amplified the stimulatory effect of IL-1β on production of IL-1Ra protein and messenger RNA (mRNA) by both human primary hepatocytes and HepG2 cells. IL-1Ra refers to three different peptides, one secreted (sIL-1Ra) and two intracellular (icIL-1RaI and icIL-1RaII), derived from the same gene. sIL-1Ra and icIL-1RaI are the products of two different mRNA, whereas icIL-1RaII is synthesized by alternative translation initiation mainly from sIL-1Ra mRNA. Our results show that both sIL-1Ra and icIL-1RaII, but not icIL-1RaI, are produced by HepG2 cells and human hepatocytes. Transient transfection experiments as well as mRNA stability studies indicated that IL-4 stimulated sIL-1Ra production primarly at the level of transcription. Gel retardation assays showed that IL-4 induced the formation of a STAT6-DNA complex with a STAT6 binding element within the sIL-1Ra promoter, but had no effect on IL-1–induced NF-κB binding activity. In contrast to IL-1Ra, production of C-reactive protein by human primary hepatocytes was stimulated by IL-6 and decreased by the addition of IL-4.