bluuebunny/crossref_metadata_2025_split huggingface dataset:
The MKK6/p38 Stress Kinase Cascade Is Critical for Tumor Necrosis Factor-–Induced Expression of Monocyte-Chemoattractant Protein-1 in Endothelial Cells
Authors: Goebeler Matthias , Kilian Karin , Gillitzer Reinhard , Kunz Manfred , Yoshimura Teizo , Bröcker Eva-B. , Rapp Ulf R. , Ludwig Stephan 
Published: October 2019

AbstractMonocyte chemoattractant protein-1 (MCP-1), a member of the C-C subfamily of chemokines, is important for the local recruitment of leukocytes to sites of inflammatory challenge. Here, we investigated endothelial signaling pathways involving members of the mitogen-activated protein (MAP) kinase superfamily and studied their role for MCP-1 expression in endothelium. We show that tumor necrosis factor- (TNF-), a potent inflammatory activator of endothelium, leads to activation of MAP kinases ERK, p38, and JNK in human umbilical vein endothelial cells (HUVEC). Contribution of MAP kinase pathways to TNF-–induced synthesis of endothelial MCP-1 was then studied by pharmacologic inhibition and transient expression of dominant negative or constitutively active kinase mutants using flow cytometry, Northern blot, and luciferase reporter gene assays. Inhibition of Raf/MEK/ERK or SEK/JNK pathways had no significant effect on MCP-1 levels, whereas blocking the MKK6/p38 pathway by p38 inhibitors SB203580 or SB202190 or by a dominant negative mutant of MKK6, the upstream activator of p38, strongly inhibited TNF-–induced expression of MCP-1. Consistent with that finding, expression of wild-type or constitutively active MKK6 significantly enhanced the effect of limiting TNF- concentrations on MCP-1 synthesis. These data suggest a crucial role for the MKK6/p38 stress kinase cascade in TNF-–mediated endothelial MCP-1 expression.
Latent Infection and Reactivation of Human Herpesvirus 6 in Two Novel Myeloid Cell Lines
Authors: Yasukawa Masaki , Ohminami Hideki , Sada Eiji , Yakushijin Yoshihiro , Kaneko Masahiko , Yanagisawa Kohsuke , Kohno Hidehisa , Bando Shiro , Fujita Shigeru 
Published: October 2019

AbstractIt has been reported that reactivation of human herpesvirus-6 (HHV-6) causes a failure of hematopoiesis. To clarify the mechanisms of bone marrow suppression induced by HHV-6 infection, it is necessary to establish an in vitro model of HHV-6 infection in hematopoietic progenitor cells. We have established two novel Philadelphia chromosome–positive myeloid cell lines, SAS413 and SAS527, which possess different hematologic characteristics and show distinct susceptibility to infection by HHV-6, from a patient with blast crisis of chronic myelogenous leukemia (CML). HHV-6 subgroup A (HHV-6A) showed marked replication in SAS413, forming syncytia and inducing cell lysis in short-term culture. On the other hand, HHV-6A–inoculated SAS527 continued to proliferate without cell lysis and only a few cells showed HHV-6 antigen expression. In contrast to HHV-6A infection, inoculation with HHV-6 subgroup B (HHV-6B) did not induce any cytopathic effect (CPE) or viral antigen expression in either of the cell lines. Although HHV-6B replication was undetectable, the presence of the HHV-6 genome in both cell lines was shown by polymerase chain reaction (PCR) during culture for more than 10 months, suggesting that HHV-6B latently infected SAS413 and SAS527. Phorbol ester treatment of SAS527 latently infected with HHV-6B resulted in reactivation of HHV-6, as shown by the appearance of a CPE, positive reactivity for the HHV-6 antigen, and isolation of infectious HHV-6. These novel cell lines should be useful for studying the mechanisms of HHV-6–induced hematopoietic failure and HHV-6 latency and reactivation, as well as differentiation, of the myeloid cell lineage.
Interferon-γ Upregulates CCR5 Expression in Cord and Adult Blood Mononuclear Phagocytes
Authors: Hariharan Deepa , Douglas Steven D. , Lee Benhur , Lai Jian-Ping , Campbell Donald E. , Ho Wen-Zhe 
Published: October 2019

AbstractThe C-C chemokine receptors CCR5 and CCR3 are fusion coreceptors for human immunodeficiency virus (HIV) entry into macrophages. The regulation of their expression influences infectivity by HIV. We report here that interferon-γ (IFN-γ) a cytokine that has bidirectional effects on HIV infection of macrophages, significantly upregulated CCR5 and CCR3 cell surface expression in human mononuclear phagocytes isolated from placental cord blood and adult peripheral blood. Monocytes treated with IFN-γ showed increased chemotaxis to the CCR5 ligands macrophage inflammatory protein-1 (MIP-1) and MIP-1β, confirming the functional relevance of IFN-γ–induced CCR5 expression. However, IFN-γ suppressed HIV entry into macrophages. Interestingly, we demonstrated that IFN-γ inhibited cell surface expression of CD4, the major receptor for HIV. This finding may explain the suppressive effect of IFN-γ on HIV entry into macrophages, despite its enhancing effect on the expression of CCR5 and CCR3 by these cells. In addition, IFN-γ–induced secretion of C-C chemokines (RANTES, MIP-1, and MIP-1β) by mononuclear phagocytes may also suppress HIV entry into macrophages. These data provide further evidence for cytokine-mediated regulation of CCR5 expression and are consistent with a novel paradigm in which cytokines regulate HIV infection and leukocyte migration by reciprocal and opposing effects on the expression of CD4 and chemokine receptors.
Sialylation of the Sialic Acid Binding Lectin Sialoadhesin Regulates Its Ability to Mediate Cell Adhesion
Authors: Barnes Yvonne C. , Skelton Tim P. , Stamenkovic Ivan , Sgroi Dennis C. 
Published: October 2019

AbstractThe macrophage-specific cell surface receptor sialoadhesin, which is a member of the newly recognized family of sialic acid binding lectins called siglecs, binds glycoprotein and glycolipid ligands containing a2-3–linked sialic acid on the surface of several leukocyte subsets. Recently, the sialic acid binding activity of the siglec CD22 has been demonstrated to be regulated by sialylation of the CD22 receptor molecule. In the present work, we show that desialylation of in vivo macrophage sialylconjugates enhances sialoadhesin-mediated lectin activity. Herein, we show that receptor sialylation of soluble sialoadhesin inhibits its binding to Jurkat cell ligands, and that charge-dependent repulsion alone cannot explain this inhibition. Furthermore, we show that the inhibitory effect of sialic acid is partially dependent on the presence of an intact exocyclic side chain. These results, in conjunction with previous findings, suggest that sialylation of siglecs by specific glycosyltransferases may be a common mechanism by which siglec-mediated adhesion is regulated.
Maturation of Embryonic Stem Cells Into Endothelial Cells in an In Vitro Model of Vasculogenesis
Authors: Hirashima Masanori , Kataoka Hiroshi , Nishikawa Satomi , Matsuyoshi Norihisa , Nishikawa Shin-Ichi 
Published: October 2019

AbstractA primitive vascular plexus is formed through coordinated regulation of differentiation, proliferation, migration, and cell-cell adhesion of endothelial cell (EC) progenitors. In this study, a culture system was devised to investigate the behavior of purified EC progenitors in vitro. Because Flk-1+ cells derived from ES cells did not initially express other EC markers, they were sorted and used as EC progenitors. Their in vitro differentiation into ECs, via vascular endothelial-cadherin (VE-cadherin)+ platelet-endothelial cell adhesion molecule-1 (PECAM-1)+ CD34−to VE-cadherin+ PECAM-1+CD34+ stage, occurred without exogenous factors, whereas their proliferation, particularly at low cell density, required OP9 feeder cells. On OP9 feeder layer, EC progenitors gave rise to sheet-like clusters of Flk-1+ cells, with VE-cadherin concentrated at the cell-cell junction. The growth was suppressed by Flt-1-IgG1 chimeric protein and dependent on vascular endothelial growth factor (VEGF) but not placenta growth factor (PIGF). Further addition of VEGF resulted in cell dispersion, indicating the role of VEGF in the migration of ECs as well as their proliferation. Cell-cell adhesion of ECs in this culture system was mediated by VE-cadherin. Thus, the culture system described here is useful in dissecting the cellular events of EC progenitors that occur during vasculogenesis and in investigating the molecular mechanisms underlying these processes.
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

AbstractInterleukin-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.
A Prospective Study on TT Virus Infection in Transfusion-Dependent Patients With β-Thalassemia
Authors: Prati Daniele , Lin Yu-Huei , De Mattei Claudia , Liu Jen-Kuei , Farma Elena , Ramaswamy Latha , Zanella Alberto , Lee Helen , Rebulla Paolo , Allain Jean-Pierre , Sirchia Girolamo , Chen Benjamin 
Published: October 2019

Abstract
A novel DNA virus designated TT virus (TTV) has been reported to be involved in the development of posttransfusion non–A-C hepatitis. We evaluated the frequency and natural course of TTV infection in a cohort of transfusion-dependent thalassemic patients in a 3-year follow-up study. Ninety-three serum hepatitis C virus (HCV) antibody-negative patients (median age of 8 years; range, 0 to 25) from eight centers were studied. Of them, 34 (37%) had an abnormal alanine-aminotransferase (ALT) baseline pattern, and the other 12 (13%) showed ALT flare-ups during the follow-up. TTV DNA in patient sera collected at the time of enrollment and at the end of follow-up was determined by polymerase chain reaction (PCR). In parallel, serum samples from 100 healthy blood donors were also tested. At baseline, 87 patient sera (93.5%) tested positive for the TTV DNA. Of these TTV DNA-positive patients, 84 (96.5%) remained viremic at the end of the study period. Of the 6 TTV DNA-negative patients, 3 acquired TTV infection during follow-up. However, no definite relation was observed between the results of TTV DNA determination and ALT patterns. TTV viremia was also detectable in 22% of blood donors. In conclusion, TTV infection is frequent and persistent among Italian transfusion-dependent patients. The high rate of viremia observed in healthy donors indicates that the parenteral route is not the only mode of TTV spread.
Role of Cytokine Signaling Molecules in Erythroid Differentiation of Mouse Fetal Liver Hematopoietic Cells: Functional Analysis of Signaling Molecules by Retrovirus-Mediated Expression
Authors: Chida Dai , Miura Osamu , Yoshimura Akihiko , Miyajima Atsushi 
Published: October 2019

AbstractErythropoietin (EPO) and its cell surface receptor (EPOR) play a central role in proliferation, differentiation, and survival of erythroid progenitors. Signals induced by EPO have been studied extensively by using erythroid as well as nonerythroid cell lines, and various controversial results have been reported as to the role of signaling molecules in erythroid differentiation. Here we describe a novel approach to analyze the EPO signaling by using primary mouse fetal liver hematopoietic cells to avoid possible artifacts due to established cell lines. Our strategy is based on high-titer retrovirus vectors with a bicistronic expression system consisting of an internal ribosome entry site (IRES) and green fluorescent protein (GFP). By placing the cDNA for a signaling molecule in front of IRES-GFP, virus-infected cells can be viably sorted by fluorescence-activated cell sorter, and the effect of expression of the signaling molecule can be assessed. By using this system, expression of cell-survival genes such as Bcl-2 and Bcl-XL was found to enhance erythroid colony formation from colony-forming unit–erythroid (CFU-E) in response to EPO. However, their expression was not sufficient for erythroid colony formation from CFU-E alone, indicating that EPO induces signals for erythroid differentiation. To examine the role of EPOR tyrosine residues in erythroid differentiation, we introduced a chimeric EGFR-EPOR receptor, which has the extracellular domain of the EGF receptor and the intracellular domain of the EPOR, as well as a mutant EGFR-EPOR in which all the cytoplasmic tyrosine residues are replaced with phenylalanine, and found that tyrosine residues of EPOR are essential for erythroid colony formation from CFU-E. We further analyzed the function of the downstream signaling molecules by expressing modified signaling molecules and found that both JAK2/STAT5 and Ras, two major signaling pathways activated by EPOR, are involved in full erythroid differentiation.
The Megakaryocyte/Platelet-Specific Enhancer of the 2β1 Integrin Gene: Two Tandem AP1 Sites and the Mitogen-Activated Protein Kinase Signaling Cascade
Authors: Zutter Mary M. , Painter Audrey D. , Yang Xun 
Published: October 2019

AbstractThe 2β1 integrin, a collagen receptor on platelets and megakaryocytes, is required for normal platelet function. Transcriptional regulation of the 2 integrin gene in cells undergoing megakaryocytic differentiation requires a core promoter between bp −30 and −92, a silencer between bp −92 and −351, and megakaryocytic enhancers in the distal 5′ flank. We have now identified a 229-bp region of the distal 5′ flank of the 2 integrin gene required for high-level enhancer activity in cells with megakaryocytic features. Two tandem AP1 binding sites with dyad symmetry are required for enhancer activity and for DNA-protein complex formation with members of the c-fos/c-jun family. The requirement for AP1 activation suggested a role for the mitogen-activated protein kinase (MAPK) signaling pathway in regulating 2 integrin gene expression. Inhibition of the MAP kinase cascade with PD98059, a specific inhibitor of MAPK kinase 1, prevented the expression of the 2 integrin subunit in cells induced to become megakaryocytic. We provide a model of megakaryocytic differentiation in which expression of the 2 integrin gene requires signaling via the MAP kinase pathway to activate two tandem AP1 binding sites in the 2 integrin enhancer.
Soluble HLA Class I, HLA Class II, and Fas Ligand in Blood Components: A Possible Key to Explain the Immunomodulatory Effects of Allogeneic Blood Transfusions
Authors: Ghio M. , Contini P. , Mazzei C. , Brenci S. , Barberis G. , Filaci G. , Indiveri F. , Puppo F. 
Published: October 2019

AbstractThe immunomodulatory effect of allogeneic blood transfusions (ABT) has been known for many years. However, a complete understanding of the effects of ABT on the recipient’s immune system has remained elusive. Soluble HLA class I (sHLA-I), HLA class II (sHLA-II), and Fas ligand (sFasL) molecules may play immunoregulatory roles. We determined by double-determinant immunoenzymatic assay (DDIA) sHLA-I, sHLA-II, and sFasL concentrations in different blood components. sHLA-I and sFasL levels in red blood cells (RBCs) stored for up to 30 days and in random-donor platelets are significantly (P &lt; .001) higher than in other blood components and their amount is proportionate to the number of residual donor leukocytes and to the length of storage. Blood components with high sHLA-I and sFasL levels play immunoregulatory roles in vitro as in allogeneic mixed lymphocyte responses (MLR) and antigen-specific cytotoxic T-cell (CTL) activity, and induce apoptosis in Fas-positive cells. These data suggest that soluble molecules in blood components are functional. If these results are paralleled in vivo, they should be taken into account in transfusion practice. Blood components that can cause immunosuppression should be chosen to induce transplantation tolerance, whereas blood components that lack immunosuppressive effects should be preferred to reduce the risk of postoperative complications and cancer recurrence.
Follicular Large Cell Lymphoma: An Aggressive Lymphoma That Often Presents With Favorable Prognostic Features
Authors: Rodriguez J. , McLaughlin P. , Hagemeister F.B. , Fayad L. , Rodriguez M.A. , Santiago M. , Hess M. , Romaguera J. , Cabanillas F. 
Published: October 2019

Abstract
It is debated whether follicular large cell lymphoma (FLCL) has a clinical behavior that is distinct from indolent follicular lymphomas, and whether there is a subset of patients who can be potentially cured. We report here our experience with 100 FLCL patients treated at our institution since 1984 with three successive programs. We evaluated the predictive value of pretreatment clinical features, including two risk models, the Tumor Score System and the International Prognostic Index (IPI). With a median follow-up of 67 months, the 5-year survival is 72% and the failure-free survival (FFS) is 67%, with a possible plateau in the FFS curve, particularly for patients with stage I-III disease. Features associated with shorter survival included age ≥60, elevated lactic dehydrogenase (LDH) or beta-2-microglobulin (β2M), advanced stage, and bone marrow involvement. Stage III patients had significantly better survival than stage IV patients (P &lt; .05). By the IPI and Tumor Score System, 80% of the patients were in the lower risk groups; both systems stratified patients into prognostic groups. Patients with FLCL have clinical features and response to treatment similar to that reported for diffuse large cell lymphoma. Prognostic risk systems for aggressive lymphomas are useful for FLCL. A meaningful fraction of patients may possibly be cured when treated as aggressive lymphomas.
Interaction Between Terminal Complement Proteins C5b-7 and Anionic Phospholipids
Authors: Liu Clive , Marshall Patricia , Schreibman Ian , Vu Ann , Gai Weiming , Whitlow Michael 
Published: October 2019

AbstractWe have recently shown that C5b-6 binds to the erythrocyte membrane via an ionic interaction with sialic acid before the addition of C7 and subsequent membrane insertion. In this study we assessed the role of anionic lipids in the binding of the terminal complement proteins to the membrane and the efficiency of subsequent hemolysis. Human erythrocytes were modified by insertion of dipalmitoyl phosphatidylcholine (DPPC), dipalmitoyl phosphatidylserine (DPPS), dipalmitoyl phosphatidylethanolamine (DPPE), or dipalmitoyl phosphatidic acid (DPPA). Lipid incorporation and the hemolytic assays were done in the presence of 100 μmol/L sodium orthovanadate to prevent enzymatic redistribution of lipid. We found that the neutral lipids, DPPC and DPPE, did not affect C5b-7 uptake or hemolysis by C5b-9. In contrast, the two acidic phospholipids, DPPS and DPPA, caused a dose-dependent increase in both lysis and C5b-7 uptake. We conclude that the presence of anionic lipids on the exterior face of the membrane increases C5b-7 uptake and subsequent hemolysis. It is known that sickle cell erythrocytes have increased exposure of phosphatidylserine on their external face and are abnormally sensitive to lysis by C5b-9. The data presented here provide a plausible mechanism for this increased sensitivity.
Identification of Cord Blood Dendritic Cells as an Immature CD11c− Population
Authors: Sorg Rüdiger V. , Kögler Gesine , Wernet Peter 
Published: October 2019

AbstractDendritic cells (DC) are the main stimulators of primary T-cell responses and, thus, probably play a role in the immune reactions after stem cell transplantation. Very little is known about DC in cord blood (CB) and about their potential involvement in the low incidence and severity of acute graft-versus-host disease after CB transplantation. Here, CBDC were identified as a HLA-DR+ cell population, lacking the CD3, CD11b, CD14, CD16, CD19, CD34, CD56, and glycophorin A lineage markers (lin). This lin−/HLA-DR+population represented 0.3% ± 0.1% (mean ± SD; range, 0.1% to 0.6%; n = 15) of CB mononuclear cells, and CB contained 5.4 ± 3.2 × 103 CBDC/mL (1.8 to 13.0 × 103; n = 15). CBDC expressed CD4, CD11a, CD18, CD45RA, CD50, CD54, and CD123, but showed no expression of CD1a, CD11c, CD33, CD40, CD45R0, CD80, CD83, and CD86 and only limited expression of CD58, CD102, and CD116. Despite this immature phenotype, immunomagnetically lin−-enriched CBDC were potent stimulators of allogeneic CB T cells. As few as 266 ± 107 (193 to 530; n = 10) lin−/HLA-DR+ CBDC stimulated a significant response. However, CBDC failed to take up protein or peptide antigens. Thus, in CB there is a prevalence of a DC subpopulation, resembling the CD11c− DC identified in tonsils, the so-called plasmacytoid T cells, which may exert a function distinct from the CD11c+ DC subpopulation.
Graft-Versus-Leukemia Effect and Graft-Versus-Host Disease Can Be Differentiated by Cytotoxic Mechanisms in a Murine Model of Allogeneic Bone Marrow Transplantation
Authors: Tsukada Nobuhiro , Kobata Tetsuji , Aizawa Yoshifusa , Yagita Hideo , Okumura Ko 
Published: October 2019

AbstractAllogeneic bone marrow transplantation (allo-BMT) is associated with both graft-versus-host disease (GVHD) and graft-versus-leukemia (GVL) effect. In the present study, we examined the contribution of cytotoxic effector mechanisms, which are mediated by tumor necrosis factor- (TNF-), Fas ligand (FasL), or perforin, to GVHD and GVL effect in a murine BMT model. Bone marrow cells plus spleen cells (BMS) from wild-type, FasL-defective, or perforin-deficient donors were transferred into lethally irradiated recipients in the parent (C57BL/6) to F1 (C57BL/6 × DBA/2) BMT model with or without prior inoculation of DBA/2 leukemia L1210 or P815 mast cytoma cells. The effect of anti–TNF- antibody administration was also examined. Whereas the defect or blockade of each cytotoxic pathway could ameliorate lethal acute GVHD, the GVL effect was differentially affected. The wild-type BMS recipients died of acute GVHD within 50 days without residual leukemia cells. The FasL-defective BMS recipients showed 60%&lt; survival over 80 days without acute GVHD or residual leukemia cells. Administration of anti–TNF- antibody resulted in early leukemia relapse and the recipients died within 25 days with massive leukemia infiltration in the liver. The perforin-deficient BMS recipients died within 60 days with residual leukemia cells. These results suggest that blockade of the Fas/FasL pathway could be used for ameliorating GVHD without impairing GVL effect in allo-BMT.