bluuebunny/crossref_metadata_2025_split huggingface dataset:
Platelet-Derived Chemokines CXC Chemokine Ligand (CXCL)7, Connective Tissue-Activating Peptide III, and CXCL4 Differentially Affect and Cross-Regulate Neutrophil Adhesion and Transendothelial Migration
Authors: Schenk Birgit I. , Petersen Frank , Flad Hans-Dieter , Brandt Ernst 
Published: April 2014

Abstract
In this study, we have examined the major platelet-derived CXC chemokines connective tissue-activating peptide III (CTAP-III), its truncation product neutrophil-activating peptide 2 (CXC chemokine ligand 7 (CXCL7)), as well as the structurally related platelet factor 4 (CXCL4) for their impact on neutrophil adhesion to and transmigration through unstimulated vascular endothelium. Using monolayers of cultured HUVEC, we found all three chemokines to promote neutrophil adhesion, while only CXCL7 induced transmigration. Induction of cell adhesion following exposure to CTAP-III, a molecule to date described to lack neutrophil-stimulating capacity, depended on proteolytical conversion of the inactive chemokine into CXCL7 by neutrophils. This was evident from experiments in which inhibition of the CTAP-III-processing protease and simultaneous blockade of the CXCL7 high affinity receptor CXCR-2 led to complete abrogation of CTAP-III-mediated neutrophil adhesion. CXCL4 at substimulatory dosages modulated CTAP-III- as well as CXCL7-induced adhesion. Although cell adhesion following exposure to CTAP-III was drastically reduced, CXCL7-mediated adhesion underwent significant enhancement. Transendothelial migration of neutrophils in response to CXCL7 or IL-8 (CXCL8) was subject to modulation by CTAP-III, but not CXCL4, as seen by drastic desensitization of the migratory response of neutrophils pre-exposed to CTAP-III, which was paralleled by selective down-modulation of CXCR-2. Altogether our results demonstrate that there exist multiple interactions between platelet-derived chemokines in the regulation of neutrophil adhesion and transendothelial migration.
Lipopolysaccharide Signals an Endothelial Apoptosis Pathway Through TNF Receptor-Associated Factor 6-Mediated Activation of c-Jun NH2-Terminal Kinase
Authors: Hull Christopher , McLean Graeme , Wong Fred , Duriez Patrick J. , Karsan Aly 
Published: April 2014

Abstract
Inflammatory mediators such as TNF and bacterial LPS do not cause significant apoptosis of endothelial cells unless the expression of cytoprotective genes is blocked. In the case of TNF, the transcription factor NF-κB conveys an important survival signal. In contrast, even though LPS can also activate NF-κB, this signal is dispensable for LPS-inducible cytoprotective activity. LPS intracellular signals are transmitted through a member of the Toll-like receptor family, TLR4. This family of receptors transduces signals through a downstream molecule, TNFR-associated factor 6 (TRAF6). In this study, we demonstrate that the C-terminal fragment of TRAF6 (TRAF6-C) inhibits LPS-induced NF-κB nuclear translocation and c-Jun NH2-terminal kinase (JNK) activation in endothelial cells. In contrast, LPS activation of p38 kinase is not inhibited by TRAF6-C. TRAF6-C also inhibits LPS-initiated endothelial apoptosis, but potentiates TNF-induced apoptosis. LPS-induced loss of mitochondrial transmembrane potential, cytochrome c release, and caspase activation are all blocked by TRAF6-C. We demonstrate that TRAF6 signals apoptosis via JNK activation, since inhibition of JNK activation using a dominant-negative mutant also inhibits apoptosis. JNK inhibition blocks caspase activation, but the reverse is not true. Hence, JNK activation lies upstream of caspase activation in response to LPS stimulation.
The Pseudomonas Autoinducer N-(3-Oxododecanoyl) Homoserine Lactone Induces Cyclooxygenase-2 and Prostaglandin E2 Production in Human Lung Fibroblasts: Implications for Inflammation
Authors: Smith Roger S. , Kelly Rodney , Iglewski Barbara H. , Phipps Richard P. 
Published: April 2014

Abstract
Pseudomonas aeruginosa causes lethal lung infections in immunocompromised individuals such as those with cystic fibrosis. The lethality of these infections is directly associated with inflammation and lung tissue destruction. P. aeruginosa produces several acylated homoserine lactones (AHL) that are important in the regulation of bacterial virulence factors. Little is known about the effects of AHLs on human cells. In this work we report that the AHL N-(3-oxododecanoyl) homoserine lactone (3O-C12-HSL) from P. aeruginosa induces cyclooxygenase (Cox)-2, a seminal proinflammatory enzyme. When primary normal human lung fibroblasts were exposed to 3O-C12-HSL, an 8-fold induction in mRNA and a 35-fold increase in protein for Cox-2 were observed. In contrast, there was no substantial change in the expression of Cox-1. We also demonstrated that the induction of Cox-2 was regulated by 3O-C12-HSL activation of the transcription factor NF-κB. 3O-C12-HSL also stimulated an increase in the newly discovered inducible membrane-associated PGE synthase but had no effect on the expression of the cytosolic PGE synthase. We also demonstrate that 3O-C12-HSL stimulated the production of PGE2. PGE2 is known to induce mucus secretion, vasodilation, and edema, and acts as an immunomodulatory lipid mediator. We propose that 3O-C12-HSL induction of Cox-2, membrane-associated PGE synthase, and PGE2 likely contributes to the inflammation and lung pathology induced by P. aeruginosa infections in the lung. These studies further reinforce the concept that bacterial AHLs not only regulate bacterial virulence but also stimulate the activities of eukaryotic cells important for inflammation and immune defenses.
The Role of Matrix Metalloproteinase-2 and Matrix Metalloproteinase-9 in Antibody-Induced Arthritis
Authors: Itoh Takeshi , Matsuda Hidetoshi , Tanioka Masatoshi , Kuwabara Kenji , Itohara Shigeyoshi , Suzuki Ryuji 
Published: April 2014

Abstract
Matrix metalloproteinases (MMPs) are a large group of enzymes responsible for matrix degradation. Among them, the family of gelatinases (MMP-2/gelatinase A and MMP-9/gelatinase B) is overproduced in the joints of patients with rheumatoid arthritis. Because of their degradative effects on the extracellular matrix, gelatinases have been believed to play an important role in progression and cartilage degradation in this disease, although their precise roles are yet to be defined. To clarify these roles, we investigated the development of Ab-induced arthritis, one of the murine models of rheumatoid arthritis, in MMP-2 or MMP-9 knockout (KO) mice. Surprisingly, the MMP-2 KO mice exhibited severe clinical and histologic arthritis than wild-type mice. The MMP-9 KO mice displayed milder arthritis. Recovery from exacerbated arthritis in the MMP-2 KO mice was possible by injection of wild-type fibroblasts. These results indicated a suppressive role of MMP-2 and a pivotal role of MMP-9 in the development of inflammatory joint disease.
A Profibrotic Function of IL-12p40 in Experimental Pulmonary Fibrosis
Authors: Huaux Francois , Arras Mohammed , Tomasi David , Barbarin Virginie , Delos Monique , Coutelier Jean-Paul , Vink Anne , Phan Sem H. , Renauld Jean-Christophe , Lison Dominique 
Published: April 2014

AbstractThe p40 subunit of IL-12 (IL-12p40), but not the heterodimeric form IL-12p70, is secreted during the development of silica-induced lung fibrosis in C57BL/6 mice. To delineate the contribution of IL-12p40 to the lung inflammatory and fibrotic processes, we compared the pulmonary responses with silica particles of IL-12p35-deficient mice (IL-12p35−/−, able to produce IL-12p40) and IL-12p40-deficient mice (IL-12p40−/−). IL-12p35−/− and IL-12p40−/− animals developed strikingly contrasting responses to silica in comparison with wild-type C57BL/6 mice. Although the IL-12p40−/− mice exhibited limited inflammatory and fibrotic reactions, the IL-12p35−/− mice presented a robust and well-developed pulmonary inflammation and fibrosis. Furthermore, the silica-induced increase in lung IL-12p40 content was significantly higher in IL-12p35−/− mice than in wild-type controls, and was associated with extensive lung fibrosis and pulmonary macrophage infiltration. The contrasting responses observed between these two IL-12 subunit-deficient murine strains were not accompanied by a strict type 1 or type 2 polarization as estimated by the measurements of lung IFN-γ/IgG2a and IL-4/IgG1 content. In vitro proliferation, type I collagen expression, as well as myofibroblast differentiation of purified pulmonary fibroblasts were not affected by treatment with exogenous rIL-12p40. In vivo, supplementation with rIL-12p40 restored the impaired pulmonary fibrotic response and macrophage accumulation in silica-treated IL-12p40−/− mice, and also promoted fibrosis and macrophage influx in wild-type mice. Together, our data suggest that IL-12p40 plays an important role in silica-induced pulmonary inflammation and fibrosis, possibly by exacerbating macrophage recruitment.
Tryptase Activates the Mitogen-Activated Protein Kinase/Activator Protein-1 Pathway in Human Peripheral Blood Eosinophils, Causing Cytokine Production and Release
Authors: Temkin Vladislav , Kantor Boris , Weg Vivian , Hartman Mor-Li , Levi-Schaffer Francesca 
Published: April 2014

AbstractWe have previously shown that mast cells enhance eosinophil survival and activation. In this study we further characterized mast cell activity toward eosinophils. Sonicate of both rat peritoneal mast cells and the human mast cell line 1 (HMC-1) induced a concentration-dependent IL-6 and IL-8 release from human peripheral blood eosinophils (ELISA). HMC-1-induced IL-8 release was significantly reduced by the tryptase inhibitors GW-45 and GW-58 (90 and 87%, respectively, at an optimal concentration) but not by anti-stem cell factor, anti-TNF-α, or anti-IFN-γ neutralizing Abs or by the antihistamine drugs pyrilamine and cimetidine. In a manner similar to HMC-1, human recombinant tryptase induced the expression of mRNA for IL-8 (RT-PCR) and caused IL-8 release from the eosinophils. Addition of cycloheximide, actinomycin D, dexamethasone, PD 98059, curcumin, or SB 202190 completely inhibited the tryptase-induced IL-6 and IL-8 release. In contrast, cyclosporin A had no effect on tryptase-induced IL-8 release. Tryptase caused phosphorylation of extracellular signal-regulated kinases 1 and 2, c-Jun N-terminal kinases 1 and 2, and p38 (Western blot). Tryptase also induced the translocation of c-Jun from the cytosol to the nucleus (confocal microscopy) and enhanced AP-1 binding activity to the DNA (EMSA). Eosinophils were found to express proteinase-activated receptor 2 (FACS). When eosinophils were incubated with tryptase in the presence of anti-proteinase-activated receptor 2 antagonist Abs a significant decrease in the IL-6 and IL-8 release occurred. In summary, we have demonstrated that the preformed mast cell mediator tryptase induces cytokine production and release in human peripheral blood eosinophils by the mitogen-activated protein kinase/AP-1 pathway.
Prevention of Chronic Rejection in Murine Cardiac Allografts: A Comparison of Chimerism- and Nonchimerism-Inducing Costimulation Blockade-Based Tolerance Induction Regimens
Authors: Shirasugi Nozomu , Adams Andrew B. , Durham Megan M. , Lukacher Aron E. , Xu Huaying , Rees Phyllis , Cowan Shannon R. , Williams Matthew A. , Pearson Thomas C. , Larsen Christian P. 
Published: April 2014

AbstractWe have previously described a nonirradiation-based regimen combining costimulation blockade, busulfan, and donor bone marrow cells that promotes stable, high level chimerism, deletion of donor-reactive T cells, and indefinite survival of skin allografts in mice. The purpose of the current study is to determine the efficacy of this tolerance regimen in preventing acute and chronic rejection in a vascularized heart graft model and to compare this regimen with other putative tolerance protocols. Mice receiving costimulation blockade (CTLA4-Ig and anti-CD40 ligand) alone or in combination with donor cells enjoyed markedly prolonged heart graft survival and initially preserved histological structure. However, tolerance was not achieved, as evidenced by the eventual onset of chronic rejection characterized by obliterative vasculopathy and the rejection of secondary skin grafts. In contrast, following treatment with costimulation blockade, busulfan, and bone marrow, heart grafts survived indefinitely without detectable signs of chronic rejection or structural damage, even 100 days after placement of a secondary donor skin graft. We detected multilineage chimerism in peripheral blood, spleen, lymph nodes, and thymus, and peripheral deletion of donor-reactive cells was complete by day 90. These findings indicate that only the CD40/CD28 blockade chimerism induction regimen prevents both acute and chronic rejection of vascularized organ transplants. Further testing of these strategies in a preclinical large animal model is warranted.
Translocation of an Intracellular Antigen to the Surface of Medullary Breast Cancer Cells Early in Apoptosis Allows for an Antigen-Driven Antibody Response Elicited by Tumor-Infiltrating B Cells
Authors: Hansen Margit H. , Nielsen Heidi V. , Ditzel Henrik J. 
Published: April 2014

Abstract
Tumor-infiltrating lymphoplasmacytic cells are a key feature of medullary carcinoma of the breast (MCB), a distinct subtype of human breast cancer that, despite cytologically anaplastic characteristics, has a more favorable prognosis than other types of breast cancer. Since it has been proposed that the improved clinical outcome is due at least in part to the presence of a prominent lymphoplasmacytic cell infiltrate in the tumor stroma, we recently examined the tumor-infiltrating B cell response in MCB and showed that it is oligoclonal and directed against an intracellular protein translocated to the cell surface upon MCB cell apoptosis. Human Abs cloned from MCB lymphoplasmacytic infiltrate-derived phage display libraries and reflecting the dominant part of the response were used to identify the target Ag as actin. Here, we have characterized in detail the cloned human IgG Abs and the translocation process of actin to the cell surface of apoptotic MCB cells. Our analysis shows that the cloned Abs bind specifically and with high affinity to actin, as determined by ELISA and surface plasmon resonance. Sequence analysis revealed that the Abs are highly somatically mutated, with high replacement to silent ratios, indicative of an Ag-driven, affinity-matured response. Interestingly, the tumor-infiltrating B cells in half the MCB patients mainly exhibited an IgG2 response, while IgG1 dominated in the others. To gain insight to the molecular events that may elicit such an Ab response, we examined the translocation of actin to the cell surface of apoptotic MCB cells using flow cytometry and laser scanning cytometry. Our results show that actin becomes exposed on the cell surface of a large proportion of apoptotic MCB cells as an early apoptotic event. We propose that the Ab response against actin produced by tumor-infiltrating B lymphoplasmacytic cells is Ag-driven, affinity-matured, and elicited due to the increased rate of apoptosis occurring within the MCB tumor that facilitates the translocation and proteolytic fragmentation of intracellular proteins.
Functional Activation of Myelin-Specific T Cells by Virus-Induced Molecular Mimicry
Authors: Olson Julie K. , Eagar Todd N. , Miller Stephen D. 
Published: April 2014

AbstractMolecular mimicry is the process by which T cells activated in response to determinants on an infecting microorganism cross-react with self epitopes, leading to an autoimmune disease. Normally, infection of SJL/J mice with the BeAn strain of Theiler’s murine encephalomyelitis virus (TMEV) results in a persistent CNS infection, leading to a chronic progressive, CD4+ T cell-mediated demyelinating disease. Myelin damage is initiated by T cell responses to virus persisting in CNS APCs, and progressive demyelinating disease (50 days postinfection) is perpetuated by myelin epitope-specific CD4+ T cells activated by epitope spreading. We developed an infectious model of molecular mimicry by inserting a sequence encompassing the immunodominant myelin epitope, proteolipid protein (PLP) 139–151, into the coding region of a nonpathogenic TMEV variant. PLP139-TMEV-infected mice developed a rapid onset paralytic inflammatory, demyelinating disease paralleled by the activation of PLP139–151-specific CD4+ Th1 responses within 10–14 days postinfection. The current studies demonstrate that the early onset demyelinating disease induced by PLP139-TMEV is the direct result of autoreactive PLP139–151-specific CD4+ T cell responses. PLP139–151-specific CD4+ T cells from PLP139-TMEV-infected mice transferred demyelinating disease to naive recipients and PLP139–151-specific tolerance before infection prevented clinical disease. Finally, infection with the mimic virus at sites peripheral to the CNS induced early demyelinating disease, suggesting that the PLP139–151-specific CD4+ T cells could be activated in the periphery and traffic to the CNS. Collectively, infection with PLP139–151 mimic encoding TMEV serves as an excellent model for molecular mimicry by inducing pathologic myelin-specific CD4+ T cells via a natural virus infection.
Membrane Fas Ligand Activates Innate Immunity and Terminates Ocular Immune Privilege
Authors: Gregory Meredith S. , Repp Amanda C. , Holhbaum Andreas M. , Saff Rebecca R. , Marshak-Rothstein Ann , Ksander Bruce R. 
Published: April 2014

AbstractIt has been proposed that the constitutive expression of Fas ligand (FasL) in the eye maintains immune privilege, in part through inducing apoptosis of infiltrating Fas+ T cells. However, the role of FasL in immune privilege remains controversial due to studies that indicate FasL is both pro- and anti-inflammatory. To elucidate the mechanism(s) by which FasL regulates immune privilege, we used an ocular tumor model and examined the individual roles of the membrane-bound and soluble form of FasL in regulating ocular inflammation. Following injection into the privileged eye, tumors expressing only soluble FasL failed to trigger inflammation and grew progressively. By contrast, tumors expressing only membrane FasL 1) initiated vigorous neutrophil-mediated inflammation, 2) terminated immune privilege, and 3) were completely rejected. Moreover, the rejection coincided with activation of both innate and adaptive immunity. Interestingly, a higher threshold level of membrane FasL on tumors is required to initiate inflammation within the immune privileged eye, as compared with nonprivileged sites. The higher threshold is due to the suppressive microenvironment found within aqueous humor that blocks membrane FasL activation of neutrophils. However, aqueous humor is unable to completely block the proinflammatory effects of tumor cells that express high levels of membrane FasL. In conclusion, our data indicate that the function of FasL on intraocular tumors is determined by the microenvironment in conjunction with the form and level of FasL expressed.
IL-2 Receptor Blockade Inhibits Late, But Not Early, IFN-γ and CD40 Ligand Expression in Human T Cells: Disruption of Both IL-12-Dependent and -Independent Pathways of IFN-γ Production
Authors: McDyer John F. , Li Zhuqing , John Susan , Yu Xiang , Wu Chang-you , Ragheb Jack A. 
Published: April 2014

AbstractmAbs directed against the α-chain (Tac/CD25) of the IL-2R are an emerging therapy in both transplantation and autoimmune disease. However, the mechanisms underlying their therapeutic efficacy have not been fully elucidated. Therefore, we examined the affect of IL-2R blockade on Th1 and Th2 cytokine production from human PBMC. Addition of a humanized anti-Tac Ab (HAT) to activated PBMC cultures inhibited IFN-γ production from CD4 and CD8 T cells by 80–90%. HAT partially inhibited production of TNF-α and completely inhibited production of IL-4, IL-5, and IL-10. Furthermore, IL-12, a central regulatory cytokine that induces IFN-γ, was undetectable in treated cultures. As T cell-dependent induction of IL-12 is regulated via CD40/CD40 ligand (CD40L) interactions, we examined the affect of HAT on CD40L expression. We found CD40L expression to be biphasic with an early (6 h) peak that is CD28/IL-2-independent, but a later peak (48 h) being CD28/IL-2-dependent and inhibited by HAT. Similarly, IFN-γ production at 6 h was CD28/IL-2-independent but CD28/IL-2-dependent and inhibited by HAT at 48 h. Nonetheless, addition of rCD40L or exogenous IL-12 to HAT-treated cultures could not restore IFN-γ production. The IFN-γ deficit in such cultures appears to be due to a direct inhibition by HAT of IL-12-independent IFN-γ production from T cells rather than altered expression of either the IL-12Rβ1 or IL-12Rβ2 chains. These data demonstrate that IL-2 plays a critical role in the regulation of Th1 and Th2 responses and impacts both IL-12-dependent and -independent IFN-γ production.
New Insights into the Functionality of a Virion-Anchored Host Cell Membrane Protein: CD28 Versus HIV Type 1
Authors: Giguère Jean-François , Paquette Jean-Sébastien , Bounou Salim , Cantin Réjean , Tremblay Michel J. 
Published: April 2014

AbstractIt is now well established that the HIV type 1 (HIV-1) incorporates a vast array of host-encoded molecules in its envelope during the budding process. Interestingly, it was demonstrated that the attachment process is accentuated by supplementary interactions between virion-anchored host molecules and their cognate ligands. Such an enhancement of the viral attachment process was found to result in an increase of infectivity for both T and macrophage-tropic strains of HIV-1. Given that previous work indicates that HIV-1 is budding at the site of cell-to-cell contact, a location rich in the costimulatory CD28 glycoprotein, we investigated whether CD28 could be efficiently acquired by HIV-1. We have been able to generate progeny viruses bearing or not bearing on their surfaces host-derived CD28 using our previously described transient transfection and expression system. The physical presence of CD28 was found to markedly increase virus infectivity in a CD28/B7-dependent manner following infection of two human lymphoid cell lines expressing high levels of surface B7-1/B7-2, two natural ligands of CD28. The physiological significance of CD28 incorporation was provided by the observation that an anti-CD28 Ab decreased replication in primary human mononuclear cells of clinical isolates of HIV-1 propagated in such cells. A virus precipitation assay revealed that M-, T-, and dual-tropic clinical strains of HIV-1 produced in primary human mononuclear cells do indeed incorporate CD28. These results show for the first time that HIV-1 can incorporate CD28 and the acquisition of this specific host surface glycoprotein modulates the virus life cycle.