bluuebunny/crossref_metadata_2025_split huggingface dataset:
Coexpression of IL-5 and Eotaxin-2 in Mice Creates an Eosinophil-Dependent Model of Respiratory Inflammation with Characteristics of Severe Asthma
Authors: Ochkur Sergei I. , Jacobsen Elizabeth A. , Protheroe Cheryl A. , Biechele Travis L. , Pero Ralph S. , McGarry Michael P. , Wang Huiying , O’Neill Katie R. , Colbert Dana C. , Colby Thomas V. , Shen Huahao , Blackburn Michael R. , Irvin Charles C. , Lee James J. , Lee Nancy A. 
Published: April 2014

Abstract
Mouse models of allergen provocation and/or transgenic gene expression have provided significant insights regarding the cellular, molecular, and immune responses linked to the pathologies occurring as a result of allergic respiratory inflammation. Nonetheless, the inability to replicate the eosinophil activities occurring in patients with asthma has limited their usefulness to understand the larger role(s) of eosinophils in disease pathologies. These limitations have led us to develop an allergen-naive double transgenic mouse model that expresses IL-5 systemically from mature T cells and eotaxin-2 locally from lung epithelial cells. We show that these mice develop several pulmonary pathologies representative of severe asthma, including structural remodeling events such as epithelial desquamation and mucus hypersecretion leading to airway obstruction, subepithelial fibrosis, airway smooth muscle hyperplasia, and pathophysiological changes exemplified by exacerbated methacholine-induced airway hyperresponsiveness. More importantly, and similar to human patients, the pulmonary pathologies observed are accompanied by extensive eosinophil degranulation. Genetic ablation of all eosinophils from this double transgenic model abolished the induced pulmonary pathologies, demonstrating that these pathologies are a consequence of one or more eosinophil effector functions.
Paratope Plasticity in Diverse Modes Facilitates Molecular Mimicry in Antibody Response
Authors: Krishnan Lavanya , Lomash Suvendu , Raj Beena Patricia Jeevan , Kaur Kanwal J. , Salunke Dinakar M. 
Published: April 2014

Abstract
The immune response against methyl-α-d-mannopyranoside mimicking 12-mer peptide (DVFYPYPYASGS) was analyzed at the molecular level towards understanding the equivalence of these otherwise disparate Ags. The Ab 7C4 recognized the immunizing peptide and its mimicking carbohydrate Ag with comparable affinities. Thermodynamic analyses of the binding interactions of both molecules suggested that the mAb 7C4 paratope lacks substantial conformational flexibility, an obvious possibility for facilitating binding to chemically dissimilar Ags. Favorable changes in entropy during binding indicated the importance of hydrophobic interactions in recognition of the mimicking carbohydrate Ag. Indeed, the topology of the Ag-combining site was dominated by a cluster of aromatic residues, contributed primarily by the specificity defining CDR H3. Epitope-mapping analysis demonstrated the critical role of three aromatic residues of the 12-mer in binding to the Ab. Our studies delineate a mechanism by which mimicry is manifested in the absence of either structural similarity of the epitopes or conformational flexibility in the paratope. An alternate mode of recognition of dissimilar yet mimicking Ags by the anti-peptide Ab involves plasticity associated with aromatic/hydrophobic and van der Waals interactions. Thus, antigenic mimicry may be a consequence of paratope-specific modulations rather than being dependent only on the properties of the epitope. Such modulations may have evolved toward minimizing the consequences of antigenic variation by invading pathogens.
Lung Dendritic Cells Rapidly Mediate Anthrax Spore Entry through the Pulmonary Route
Authors: Cleret Aurélie , Quesnel-Hellmann Anne , Vallon-Eberhard Alexandra , Verrier Bernard , Jung Steffen , Vidal Dominique , Mathieu Jacques , Tournier Jean-Nicolas 
Published: April 2014

Abstract
Inhalational anthrax is a life-threatening infectious disease of considerable concern, especially because anthrax is an emerging bioterrorism agent. The exact mechanisms leading to a severe clinical form through the inhalational route are still unclear, particularly how immobile spores are captured in the alveoli and transported to the lymph nodes in the early steps of infection. We investigated the roles of alveolar macrophages and lung dendritic cells (LDC) in spore migration. We demonstrate that alveolar macrophages are the first cells to phagocytose alveolar spores, and do so within 10 min. However, interstitial LDCs capture spores present in the alveoli within 30 min without crossing the epithelial barrier suggesting a specific mechanism for rapid alveolus sampling by transepithelial extension. We show that interstitial LDCs constitute the cell population that transports spores into the thoracic lymph nodes from within 30 min to 72 h after intranasal infection. Our results demonstrate that LDCs are central to spore transport immediately after infection. The rapid kinetics of pathogen transport may contribute to the clinical features of inhalational anthrax.
Depletion of CD8+ Cells in Sooty Mangabey Monkeys Naturally Infected with Simian Immunodeficiency Virus Reveals Limited Role for Immune Control of Virus Replication in a Natural Host Species
Authors: Barry Ashley P. , Silvestri Guido , Safrit Jeffrey T. , Sumpter Beth , Kozyr Natalia , McClure Harold M. , Staprans Silvija I. , Feinberg Mark B. 
Published: April 2014

Abstract
SIV infection of sooty mangabeys (SMs), a natural host species, does not cause AIDS despite high-level virus replication. In contrast, SIV infection of nonnatural hosts such as rhesus macaques (RMs) induces an AIDS-like disease. The depletion of CD8+ T cells during SIV infection of RMs results in marked increases in plasma viremia, suggesting a key role for CD8+ T cells in controlling levels of SIV replication. To assess the role that CD8+ T cells play in determining the virologic and immunologic features of nonpathogenic SIV infection in SMs, we transiently depleted CD8+ T cells in SIV-infected and uninfected SMs using a CD8α-specific Ab (OKT8F) previously used in studies of SIV-infected RMs. Treatment of SMs with the OKT8F Ab resulted in the prompt and profound depletion of CD8+ T cells. However, in contrast to CD8+ cell depleted, SIV-infected RMs, only minor changes in the levels of plasma viremia were observed in most SIV-infected SMs during the period of CD8+ cell deficiency. Those SMs demonstrating greater increases in SIV replication following CD8+ cell depletion also displayed higher levels of CD4+ T cell activation and/or evidence of CMV reactivation, suggesting that an expanded target cell pool rather than the absence of CD8+ T cell control may have been primarily responsible for transient increases in viremia. These data indicate that CD8+ T cells exert a limited influence in determining the levels of SIV replication in SMs and provide additional evidence demonstrating that the absence of AIDS in SIV-infected SMs is not due to the effective control of viral replication by cellular immune responses.
Macrophage-Inflammatory Protein-3α Mediates Epidermal Growth Factor Receptor Transactivation and ERK1/2 MAPK Signaling in Caco-2 Colonic Epithelial Cells via Metalloproteinase-Dependent Release of Amphiregulin
Authors: Keates Sarah , Han Xinbing , Kelly Ciarán P. , Keates Andrew C. 
Published: April 2014

Abstract
Previously, we reported that normal colonocytes produce the memory CD4+ T cell-directed chemokine MIP-3α, and that epithelial MIP-3α levels are elevated in inflammatory bowel disease. Interestingly, the unique receptor for MIP-3α, CCR6, is expressed by a variety of cell types including colonocytes, suggesting that MIP-3α may regulate additional biological activities in the intestine. The aim of this study was to determine whether MIP-3α can induce intestinal epithelial cell proliferation and to examine the signaling mechanisms that mediate this response. We show that nonstimulated Caco-2 and HT-29 colonic epithelial cells express CCR6, and that stimulation of Caco-2 cells by MIP-3α can dose dependently increase cell proliferation as well as activate the epidermal growth factor receptor (EGFR) and ERK1/2 MAPK. MIP-3α-mediated ERK1/2 activation in Caco-2 cells appeared to require metalloproteinase-dependent release of the endogenous EGFR ligand amphiregulin and transactivation of the EGFR. Moreover, blockade of amphiregulin bioactivity using a neutralizing polyclonal Ab significantly reduced MIP-3α-mediated, but not EGF-mediated Caco-2 cell proliferation. Taken together, our findings indicate that MIP-3α can regulate mitogenic signaling in colonic epithelial cells and thus may serve an important homeostatic function in the intestine by regulating tissue turnover and maintenance of the epithelium, in addition to its role in regulating leukocyte recruitment.
IL-10 Underlies Distinct Susceptibility of BALB/c and C57BL/6 Mice to Mycobacterium avium Infection and Influences Efficacy of Antibiotic Therapy
Authors: Roque Susana , Nobrega Claudia , Appelberg Rui , Correia-Neves Margarida 
Published: April 2014

Abstract
Increased production of IL-10 has been frequently associated with augmented susceptibility to infection. However, the correlation between IL-10 activity and susceptibility to mycobacterial infection is still uncertain. Although studies using transgenic mice overexpressing IL-10 consistently showed an increased susceptibility to mycobacterial infection, experimental approaches in which IL-10 activity was reduced or abrogated originated inconclusive data. We show here that this controversy might be due to the mouse strains used in the various experimental procedures. Our results show that BALB/c mice are more susceptible than C57BL/6 to Mycobacterium avium infection. This increased susceptibility of BALB/c mice is, to a great extent, due to distinct activity of IL-10 between the two mouse strains. In accordance, reduction of IL-10 activity through the administration of anti-IL-10R mAb, or the absence of IL-10 as studied in IL-10 knockout mice, clearly decreased the susceptibility of BALB/c mice to M. avium but had a less obvious effect in C57BL/6 mice. Moreover, abrogation of IL-10 activity in infected BALB/c mice increased the efficacy of antimycobacterial therapy, whereas for the C57BL/6 mice it produced no effect. These observations show that the activity of IL-10 in response to the same mycobacterial stimulus influences not only the susceptibility to infection but also the efficacy of antimycobacterial therapy. This should now be considered in the context of human response to mycobacterial infection, particularly as a possible strategy to improve treatment against infections by mycobacteria.
Leukotriene B4 Triggers the In Vitro and In Vivo Release of Potent Antimicrobial Agents
Authors: Flamand Louis , Tremblay Michel J. , Borgeat Pierre 
Published: April 2014

Abstract
Leukotriene B4 (LTB4) is a bioactive lipid derived from the metabolism of arachidonic acid. Mainly produced by polymorphonuclear leukocytes (PMN) and macrophages, LTB4 triggers several functional responses important in host defense, including the secretion of lysosomal enzymes, the activation of NADPH oxidase activity, NO formation, and phagocytosis. We report that LTB4, but not structural analogs thereof, stimulates primed human PMN to release molecules having potent antimicrobial activities. Exposure of bacteria (Escherichia coli and Staphylococcus aureus) or viruses (herpes simplex virus type 1 and HIV type 1) to supernatants of LTB4-activated PMN lead to ≥90% reduction in infectivity. ELISA and mass spectroscopy analysis of proteins released from LTB4-activated PMN have identified several antimicrobial proteins, including α-defensins, cathepsin G, elastase, lysozyme C, and LL-37, that are likely to participate in the killing of microorganisms. In addition to these in vitro observations, i.v. injections of LTB4 (50 μg/kg) to monkeys led to an increase in α-defensin plasmatic levels and enhanced ex vivo antimicrobial activities of plasma. These results demonstrate the ability of LTB4 to cause the release of potent antimicrobial agents from PMN in vitro as well as in vivo and add further support to the important role of LTB4 in host defense.
Human Neutrophil Defensins Increase Neutrophil Uptake of Influenza A Virus and Bacteria and Modify Virus-Induced Respiratory Burst Responses
Authors: Tecle Tesfaldet , White Mitchell R. , Gantz Don , Crouch Erika C. , Hartshorn Kevan L. 
Published: April 2014

AbstractHuman neutrophil peptides (HNPs) are released from granules of neutrophils in response to various activating stimuli and they participate in the killing of bacteria and the stimulation of various inflammatory responses. HNPs also inhibit infectivity of enveloped viruses, including influenza A virus (IAV). In this study, we demonstrate that HNPs increase the uptake of IAV and bacteria by neutrophils. The dimeric HNPs also induced aggregation of IAV and bacterial particles, which may, in part, explain their ability to increase uptake. HNPs did not increase neutrophil respiratory burst responses to IAV. We have recently demonstrated direct interactions of HNPs with surfactant protein D (SP-D), another important effector of innate immunity and antimicrobial host defense. Although HNPs did not alter SP-D-dependent uptake of IAV, they counteracted the ability of SP-D to increase IAV-induced neutrophil H2O2 generation. Our studies reveal previously unappreciated functional effects of HNPs, expand our understanding of the antiviral properties of HNPs, and suggest important interactions between collectins and HNPs in the host response to viruses and bacteria.
Expression and Regulation of the Metalloproteinase ADAM-8 during Human Neutrophil Pathophysiological Activation and Its Catalytic Activity on L-Selectin Shedding
Authors: Gómez-Gaviro Maria , Domínguez-Luis Maria , Canchado Javier , Calafat Jero , Janssen Hans , Lara-Pezzi Enrique , Fourie Anne , Tugores Antonio , Valenzuela-Fernández Agustín , Mollinedo Faustino , Sánchez-Madrid Francisco , Díaz-González Federico 
Published: April 2014

Abstract
A disintegrin and metalloproteinase domain (ADAM) proteins are a family of transmembrane glycoproteins with heterogeneous expression profiles and proteolytic, cell-adhesion, -fusion, and -signaling properties. One of its members, ADAM-8, is expressed by several cell types including neurons, osteoclasts, and leukocytes and, although it has been implicated in osteoclastogenesis and neurodegenerative processes, little is known about its role in immune cells. In this study, we show that ADAM-8 is constitutively present both on the cell surface and in intracellular granules of human neutrophils. Upon in vitro neutrophil activation, ADAM-8 was mobilized from the granules to the plasma membrane, where it was released through a metalloproteinase-dependent shedding mechanism. Adhesion of resting neutrophils to human endothelial cells also led to up-regulation of ADAM-8 surface expression. Neutrophils isolated from the synovial fluid of patients with active rheumatoid arthritis expressed higher amounts of ADAM-8 than neutrophils isolated from peripheral blood and the concentration of soluble ADAM-8 in synovial fluid directly correlated with the degree of joint inflammation. Remarkably, the presence of ADAM-8 both on the cell surface and in suspension increased the ectodomain shedding of membrane-bound L-selectin in mammalian cells. All these data support a potential relevant role for ADAM-8 in the function of neutrophils during inflammatory response.
Regulated Shedding of Transmembrane Chemokines by the Disintegrin and Metalloproteinase 10 Facilitates Detachment of Adherent Leukocytes
Authors: Hundhausen Christian , Schulte Alexander , Schulz Beate , Andrzejewski Michael G. , Schwarz Nicole , von Hundelshausen Philipp , Winter Ulrike , Paliga Krzysztof , Reiss Karina , Saftig Paul , Weber Christian , Ludwig Andreas 
Published: April 2014

Abstract
CX3CL1 (fractalkine) and CXCL16 are unique members of the chemokine family because they occur not only as soluble, but also as membrane-bound molecules. Expressed as type I transmembrane proteins, the ectodomain of both chemokines can be proteolytically cleaved from the cell surface, a process known as shedding. Our previous studies showed that the disintegrin and metalloproteinase 10 (ADAM10) mediates the largest proportion of constitutive CX3CL1 and CXCL16 shedding, but is not involved in the phorbolester-induced release of the soluble chemokines (inducible shedding). In this study, we introduce the calcium-ionophore ionomycin as a novel, very rapid, and efficient inducer of CX3CL1 and CXCL16 shedding. By transfection in COS-7 cells and ADAM10-deficient murine embryonic fibroblasts combined with the use of selective metalloproteinase inhibitors, we demonstrate that the inducible generation of soluble forms of these chemokines is dependent on ADAM10 activity. Analysis of the C-terminal cleavage fragments remaining in the cell membrane reveals multiple cleavage sites used by ADAM10, one of which is preferentially used upon stimulation with ionomycin. In adhesion studies with CX3CL1-expressing ECV-304 cells and cytokine-stimulated endothelial cells, we demonstrate that induced CX3CL1 shedding leads to the release of bound monocytic cell lines and PBMC from their cellular substrate. These data provide evidence for an inducible release mechanism via ADAM10 potentially important for leukocyte diapedesis.
Histamine 4 Receptor Activation Induces Recruitment of FoxP3+ T Cells and Inhibits Allergic Asthma in a Murine Model
Authors: Morgan Ross K. , McAllister Brian , Cross Lillian , Green Daniel S. , Kornfeld Hardy , Center David M. , Cruikshank William W. 
Published: April 2014

Abstract
Histamine has an important role in regulation of immune response which is mediated by differential expression of four distinct receptors, H1R–H4R. H1R and HR2 have previously been shown to be involved with modulation of lung inflammation. H4R is also expressed on inflammatory cells; therefore, we investigated the potential role of H4R in development of allergic asthma in a murine model. We determined that the H4R agonist 4-methylhistamine when delivered intratracheally before Ag challenge mitigated airway hyperreactivity and inflammation. This was associated with an increase in IL-10 and IFN-γ, but not TGF-β or IL-16, as well as a decrease in IL-13 in the bronchoalveolar lavage fluid. We also observed that H4R agonist instillation resulted in accumulation of FoxP3+ T cells suggesting a direct effect on T regulatory cell recruitment. To investigate this further, we determined the in vitro effect of H4R stimulation on human T cell migration. The H4R agonist induced a 2- to 3-fold increase in T cell migration, similar to that seen for H1R agonists. Cells transmigrating to the H4R agonist, but not H1R, were skewed toward a CD4 cell expressing CD25 and intracellular FoxP3. H4R-responsive cells suppressed proliferation of autologous T cells, an effect that was dependent on IL-10 production. We conclude that H4R stimulation enriches for a regulatory T cell with potent suppressive activity for proliferation. These findings identify a novel function for H4R and suggest a potential therapeutic approach to attenuation of asthmatic inflammation.
TNF-α Inhibits Macrophage Clearance of Apoptotic Cells via Cytosolic Phospholipase A2 and Oxidant-Dependent Mechanisms
Authors: McPhillips Kathleen , Janssen William J. , Ghosh Moumita , Byrne Aideen , Gardai Shyra , Remigio Linda , Bratton Donna L. , Kang Jihee L. , Henson Peter 
Published: April 2014

Abstract
Removal of apoptotic cells from inflammatory sites is an important step in the resolution of inflammation. Both murine and human macrophages stimulated with TNF-α or directly administered arachidonic acid showed an impaired ability to ingest apoptotic cells (efferocytosis). The inhibition was shown to be due to generation of reactive oxygen species, was blocked with a superoxide dismutase mimetic, MnTBAP, and was mimicked by direct addition of H2O2. To determine the mechanism of TNF-α-stimulated oxidant production, bone marrow-derived macrophages from gp91phox-deficient mice were examined but shown to still produce oxidants and exhibit defective apoptotic cell uptake. In contrast, a specific cytosolic phospholipase A2 inhibitor blocked the oxidant production and reversed the inhibited uptake. The suppressive effect of endogenous or exogenous oxidants on efferocytosis was mediated through activation of the GTPase, Rho. It was reversed in macrophages pretreated with C3 transferase to inactivate Rho or with an inhibitor of Rho kinase. During maturation of human monocyte-derived macrophages, only mature cells exhibited TNF-α-induced suppression of apoptotic cell clearance. The resistance of immature macrophages to such inhibition was shown to result not from defective generation of oxidants, but rather, from lack of response of these cells to the oxidants. Overall, the data suggest that macrophages in a TNF-α- and oxidant-rich inflammatory environment are less able to remove apoptotic cells and, thereby, may contribute to the local intensity of the inflammatory response.
Identification of Ectonucleotidases CD39 and CD73 in Innate Protection during Acute Lung Injury
Authors: Eckle Tobias , Füllbier Lars , Wehrmann Manfred , Khoury Joseph , Mittelbronn Michel , Ibla Juan , Rosenberger Peter , Eltzschig Holger K. 
Published: April 2014

Abstract
Acute lung injury (ALI), such as that which occurs with mechanical ventilation, contributes to morbidity and mortality of critical illness. Nonetheless, in many instances, ALI resolves spontaneously through unknown mechanisms. Therefore, we hypothesized the presence of innate adaptive pathways to protect the lungs during mechanical ventilation. In this study, we used ventilator-induced lung injury as a model to identify endogenous mechanisms of lung protection. Initial in vitro studies revealed that supernatants from stretch-induced injury contained a stable factor which diminished endothelial leakage. This factor was subsequently identified as adenosine. Additional studies in vivo revealed prominent increases in pulmonary adenosine levels with mechanical ventilation. Because ectoapyrase (CD39) and ecto-5′-nucleotidase (CD73) are rate limiting for extracellular adenosine generation, we examined their contribution to ALI. In fact, both pulmonary CD39 and CD73 are induced by mechanical ventilation. Moreover, we observed pressure- and time-dependent increases in pulmonary edema and inflammation in ventilated cd39−/− mice. Similarly, pharmacological inhibition or targeted gene deletion of cd73 was associated with increased symptom severity of ventilator-induced ALI. Reconstitution of cd39−/− or cd73−/− mice with soluble apyrase or 5′-nucleotidase, respectively, reversed such increases. In addition, ALI was significantly attenuated and survival improved after i.p. treatment of wild-type mice with soluble apyrase or 5′-nucleotidase. Taken together, these data reveal a previously unrecognized role for CD39 and CD73 in lung protection and suggest treatment with their soluble compounds as a therapeutic strategy for noninfectious ALI.