bluuebunny/crossref_metadata_2025_split huggingface dataset:
IL-4 Induces Apoptosis in A549 Lung Adenocarcinoma Cells: Evidence for the Pivotal Role of 15-Hydroxyeicosatetraenoic Acid Binding to Activated Peroxisome Proliferator-Activated Receptor γ Transcription Factor
Authors: Shankaranarayanan Pattabhiraman , Nigam Santosh 
Published: April 2014

Abstract
The proinflammatory cytokine IL-4 is secreted in large amounts during allergic inflammatory response in asthma and plays a pivotal role in the airway inflammation. IL-4 has been shown to up-regulate 15-lipoxygenase and produce 15(S)-hydroxyeicosatetraenoic acid (15(S)-HETE) in A549 cells via the Janus kinase/STAT6 pathway under coactivation of CREB binding protein/p300. IL-4 has also been shown to up-regulate peroxisome proliferator-activated receptor γ (PPARγ) nuclear receptors in macrophages and A549 cells. In this study we demonstrate that 15(S)-HETE binds to PPARγ nuclear receptors and induces apoptosis in A549 cells. Moreover, pretreatment of cells with nordihydroguaiaretic acid, a 15-lipoxygenase inhibitor, prevented PPARγ activation and apoptosis. The latter was accomplished by the interaction of the 15(S)-HETE/PPARγ complex with the adapter protein Fas-associating protein with death domain and caspase-8, as shown by transfection of Fas-associating protein with death domain dominant negative vector and cleavage of caspase 8 to active subunits p41/42 and p18. Whereas IL-4 and PPARγ ligands failed to induce cleavage of Bid and release of cytochrome c from mitochondria, they caused translocation of the proapoptotic protein Bax from cytoplasm to mitochondria with a concomitant decrease in the Bcl-xL level. We therefore believe that in unstimulated cells Bcl-xL and Bax form a heterodimer, in which Bcl-xL dominates and prevents the induction of apoptosis, whereas in IL-4-stimulated cells the 15(S)-HETE/PPARγ complex down-regulates Bcl-xL, and the resulting overweight of Bax commits the cell to apoptosis via caspase-3. However, this pathway does not rule out the direct caspase-8-mediated activation of caspase-3. In conclusion, IL-4-induced apoptosis may contribute to severe loss of alveolar structures and infiltration of eosinophils, mononuclear phagocytes, etc., into the lung tissue of chronic asthma patients.
Lipid Raft-Independent B Cell Receptor-Mediated Antigen Internalization and Intracellular Trafficking
Authors: Putnam Michelle A. , Moquin Amy E. , Merrihew Megan , Outcalt Christopher , Sorge Emily , Caballero Adriana , Gondré-Lewis Timothy A. , Drake James R. 
Published: April 2014

AbstractThe Ag-specific B cell receptor (BCR) expressed by B lymphocytes has two distinct functions upon interaction with cognate Ag: signal transduction (generation of intracellular second messenger molecules) and Ag internalization for subsequent processing and presentation. While it is known that plasma membrane domains, termed lipid rafts, are involved in BCR-mediated signal transduction, the precise role of plasma membrane lipid rafts in BCR-mediated Ag internalization and intracellular trafficking is presently unclear. Using a highly characterized model system, it was determined that while plasma membrane lipid rafts can be internalized by B lymphocytes, lipid rafts do not represent a major pathway for the rapid and efficient internalization of cell surface Ag-BCR complexes. Moreover, internalized plasma membrane lipid rafts are delivered to intracellular compartments distinct from those to which the bulk of internalized Ag-BCR complexes are delivered. These results demonstrate that B lymphocytes, like other cell types, possess at least two distinct endocytic pathways (i.e., clathrin-coated pits and plasma membrane lipid rafts) that deliver internalized ligands to distinct intracellular compartments. Furthermore, Ag-BCR complexes differentially access these two distinct internalization pathways.
Lipid Raft Distribution of CD4 Depends on its Palmitoylation and Association with Lck, and Evidence for CD4-Induced Lipid Raft Aggregation as an Additional Mechanism to Enhance CD3 Signaling
Authors: Fragoso Roben , Ren Dejian , Zhang Xiaoping , Su Michael Wei-Chih , Burakoff Steven J. , Jin Yong-Jiu 
Published: April 2014

AbstractBy mutagenesis, we demonstrated that the palmitoylation of the membrane-proximal Cys396 and Cys399of CD4, and the association of CD4 with Lck contribute to the enrichment of CD4 in lipid rafts. Ab cross-linking of CD4 induces an extensive membrane patching on the T cell surface, which is related to lipid raft aggregation. The lipid raft localization of CD4 is critical for CD4 to induce the aggregation of lipid rafts. The localization of CD4 in lipid rafts also correlates to the ability of CD4 to enhance receptor tyrosine phosphorylation. Thus, our data suggest that CD4-induced aggregation of lipid rafts may play an additional role in CD4 signaling besides its adhesion to MHC molecules and association with Lck.
Impaired Transporter Associated with Antigen Processing (TAP) Function Attributable to a Single Amino Acid Alteration in the Peptide TAP Subunit TAP1
Authors: Ritz Ulrike , Drexler Ingo , Sutter Dirk , Abele Rupert , Huber Christoph , Seliger Barbara 
Published: April 2014

AbstractThe heterodimeric peptide transporter TAP belongs to the ABC transporter family. Sequence comparisons with the P-glycoprotein and cystic fibrosis transmembrane conductance regulator and the functional properties of selective amino acids in these ABC transporters postulated that the glutamic acid at position 263 and the phenylalanine at position 265 of the TAP1 subunit could affect peptide transporter function. To define the role of both amino acids, TAP1 mutants containing a deletion or a substitution to alanine at position 263 or 265 were generated and stably expressed in murine and human TAP1−/− cells. The different TAP1 mutants were characterized in terms of expression and function of TAP, MHC class I surface expression, immune recognition, and species-specific differences. The phenotype of murine and human cells expressing human TAP1 mutants with a deletion or substitution of Glu263 was comparable to that of TAP1−/− cells. In contrast, murine and human TAP1 mutant cells containing a deletion or mutation of Phe265 of the TAP1 subunit exhibit wild-type TAP function. This was associated with high levels of MHC class I surface expression and recognition by specific CTL, which was comparable to that of wild-type TAP1-transfected control cells. Thus, biochemical and functional evidence is presented that the Glu263 of the TAP1 protein, but not the Phe265, is critical for proper TAP function.
A Single Polymorphic Residue Within the Peptide-Binding Cleft of MHC Class I Molecules Determines Spectrum of Tapasin Dependence
Authors: Park Boyoun , Lee Sungwook , Kim Euijae , Ahn Kwangseog 
Published: April 2014

AbstractDifferent HLA class I alleles display a distinctive dependence on tapasin for surface expression and Ag presentation. In this study, we show that the tapasin dependence of HLA class I alleles correlates to the nature of the amino acid residues present at the naturally polymorphic position 114. The tapasin dependence of HLA class I alleles bearing different residues at position 114 decreases in the order of acidity, with high tapasin dependence for acidic amino acids (aspartic acid and glutamic acid), moderate dependence for neutral amino acids (asparagine and glutamine), and low dependence for basic amino acids (histidine and arginine). A glutamic acid to histidine substitution at position 114 allows the otherwise tapasin-dependent HLA-B4402 alleles to load high-affinity peptides independently of tapasin and to have surface expression levels comparable to the levels seen in the presence of tapasin. The opposite substitution, histidine to glutamic acid at position 114, is sufficient to change the HLA-B2705 allele from the tapasin-independent to the tapasin-dependent phenotype. Furthermore, analysis of point mutants at position 114 reveals that tapasin plays a principal role in transforming the peptide-binding groove into a high-affinity, peptide-receptive conformation. The natural polymorphisms in HLA class I H chains that selectively affect tapasin-dependent peptide loading provide insights into the functional interaction of tapasin with MHC class I molecules.
The GDP Exchange Factor AND-34 Is Expressed in B Cells, Associates With HEF1, and Activates Cdc42
Authors: Cai Dongpo , Felekkis Kyriakos N. , Near Richard I. , O’Neill Geraldine M. , van Seventer Jean Maguire , Golemis Erica A. , Lerner Adam 
Published: April 2014

AbstractAND-34, a novel GDP exchange factor, is expressed constitutively at significant levels in murine splenic B cells, but not in murine splenic T cells or thymocytes. In B cell lines, anti-IgM treatment up-regulates AND-34 transcript levels. B cell AND-34 associates with both the docking molecules p130Cas and HEF1. AND-34 binds by its GDP exchange factor domain to the C terminus of HEF1, a region of HEF1 previously implicated in apoptotic, adhesion, and cell cycle-regulated signaling. Overexpression of AND-34 in murine B cell lines activates the Rho family GTPase Cdc42, but not Rac, Rho, RalA, or Rap1. Consistent with this, a subpopulation of AND-34 overexpressing B cells have long filamentous actin-containing cellular extensions. AND-34 overexpression augments both autophosphorylation and kinase activity of the Cdc42/Rac-responsive serine/threonine kinase PAK1. As previously reported for lymphoid cells transfected with constitutively active Cdc42, AND-34 overexpression inhibits SDF-1α-induced B cell polarization. These studies suggest that p130Cas and HEF1-associated AND-34 may regulate B cell adhesion and motility through a Cdc42-mediated signaling pathway.
A Complex Containing Polypyrimidine Tract-Binding Protein Is Involved in Regulating the Stability of CD40 Ligand (CD154) mRNA
Authors: Kosinski Penelope A. , Laughlin Jennifer , Singh Karnail , Covey Lori R. 
Published: April 2014

AbstractCD40 ligand (CD154) expression has been shown to be regulated, in part, at the posttranscriptional level by a pathway of “regulated instability” of mRNA decay throughout a time course of T cell activation. This pathway is modulated at late times of activation by the binding of a stability complex (termed complex I) to a CU-rich region in the 3′ untranslated region of the CD154 message. We have undertaken experiments to extend these findings and to analyze the cis-acting elements and trans-acting factors involved in this regulation. We have previously shown that the minimal binding sequence for complex I is a 63 nt CU-rich motif. However, our current study shows that when this site was deleted additional complex binding was observed upstream and downstream of the minimal binding region. Only after deletion of an extended region (termed Δ1515) was complex binding completely abolished. Analysis of complex binding using competition experiments revealed that the three adjacent regions bound related but not identical complexes. However, all three sites appeared to have a 55-kDa protein as the RNA-binding protein. Deletion of the Δ1515 region resulted in reduced transcript stability as measured by both in vitro and in vivo decay assays. Finally, using Abs against known RNA-binding proteins, we identified the polypyrimidine tract-binding protein (or heterogeneous nuclear ribonucleoprotein I) as a candidate RNA-binding component of complex I.
TNF-Related Apoptosis-Inducing Ligand Mediates Tumoricidal Activity of Human Monocytes Stimulated by Newcastle Disease Virus
Authors: Washburn Birgit , Weigand Markus A. , Grosse-Wilde Anne , Janke Markus , Stahl Heiko , Rieser Eva , Sprick Martin R. , Schirrmacher Volker , Walczak Henning 
Published: April 2014

Abstract
The Newcastle disease virus (NDV) has antineoplastic and immunostimulatory properties, and it is currently clinically tested in anticancer therapy. However, the tumoricidal mechanisms of NDV tumor therapy are not fully understood. The results presented here demonstrate that NDV-stimulated human monocytes (Mφ) kill various human tumor cell lines and that this tumoricidal activity is mediated by TRAIL. In contrast to soluble TRAIL-R2-Fc, soluble CD95-Fc and TNF-R2-Fc showed only minimal blocking of the antitumor effect. TRAIL expression is induced on human Mφ after stimulation with NDV and UV-inactivated NDV. These results show that TRAIL induction on human Mφ after NDV stimulation is independent from viral replication and that TRAIL mediates the tumoricidal activity of NDV-stimulated human Mφ.
H2-M3-Restricted Memory T Cells: Persistence and Activation Without Expansion
Authors: Kerksiek Kristen M. , Ploss Alexander , Leiner Ingrid , Busch Dirk H. , Pamer Eric G. 
Published: April 2014

Abstract
H2-M3-restricted T cells respond more rapidly to primary Listeria monocytogenes infection than conventional MHC class Ia-restricted T cells. Reinfection with L. monocytogenes, while inducing explosive proliferation of H2-Kd-restricted T cells, does not stimulate significant expansion of H2-M3-restricted CTL. These disparate responses to reinfection are apparent within 5 days of primary L. monocytogenes infection. However, H2-M3-restricted memory T cells are generated, and are indistinguishable from classically restricted T cells in terms of cell surface memory markers and longevity. Early responses of H2-M3- and H2-Kd-restricted memory T cells to reinfection are similar, with increases in size and expression of activation markers. Interestingly, priming of H2-M3-restricted T cells with an L. monocytogenes-derived N-formyl peptide plus anti-CD40 generates memory T cells that expand upon re-exposure to Ag during L. monocytogenes infection. Our data indicate that disparate H2-M3- and MHC class Ia-restricted memory T cell responses reflect intrinsic differences between these T cell populations. Although distinct proliferative programs appear to be hardwired in these populations during primary L. monocytogenes infection, under different inflammatory circumstances M3-restricted T cell populations can maintain the ability to expand upon re-exposure to Ag.
Structure Function Differences in Nonpeptide CCR1 Antagonists for Human and Mouse CCR1
Authors: Onuffer James , McCarrick Margaret A. , Dunning Laura , Liang Meina , Rosser Mary , Wei Guo-Ping , Ng Howard , Horuk Richard 
Published: April 2014

Abstract
A useful strategy for identifying ligand binding domains of G protein-coupled receptors has been the exploitation of species differences in antagonist potencies. We have used this approach for the CCR1 chemokine receptor with a novel series of antagonists, the 4-hydroxypiperidines, which were discovered by high throughput screening of human CCR1 and subsequently optimized. The structure-activity relationships for a number of different 4-hydroxypiperidine antagonists for human and mouse CCR1 were examined by receptor binding and functional assays. These compounds exhibit major differences in their rank order of potency for the human and mouse chemokine receptor CCR1. For example, the initial lead template, BX 510, which was a highly potent functional antagonist for human CCR1 (Ki = 21 nM) was &gt;400-fold less active on mouse CCR1 (Ki = 9150 nM). However, increasing the length of the linker between the piperidine and dibenzothiepine groups by one methylene group generated a compound, BX 511, which was equipotent for both human and mouse CCR1. These and other analogs of the lead template BX 510, which have major differences in potency for human and mouse CCR1, are described, and a model for their interaction with human CCR1 is presented.
The Mitochondrial Network of Human Neutrophils: Role in Chemotaxis, Phagocytosis, Respiratory Burst Activation, and Commitment to Apoptosis
Authors: Fossati Gianluca , Moulding Dale A. , Spiller David G. , Moots Robert J. , White Michael R. H. , Edwards Steven W. 
Published: April 2014

Abstract
It is commonly assumed that human neutrophils possess few, if any, functional mitochondria and that they do not depend on these organelles for cell function. We have used the fluorescent mitochondrial indicators, JC-1, MitoTracker Red, and dihydrorhodamine 123 to show that live neutrophils possess a complex mitochondrial network that extends through the cytoplasm. The membrane potential of these mitochondria was rapidly (within 2 min) disrupted by the addition of FCCP (IC50 = 20 nM), but not by the Fo-ATPase inhibitor, oligomycin (at up to 7 μg/ml). However, inhibition of mitochondrial function with both agents resulted in cell shape changes. Neither activation of the respiratory burst nor phagocytosis of either latex particles or serum-opsonized Staphylococcus aureus was affected by the addition of FCCP or oligomycin. However, FCCP inhibited chemotaxis at concentrations that paralleled disruption of mitochondrial membrane potential. Furthermore, prolonged (2-h) incubation with oligomycin resulted in an impaired ability to activate a respiratory burst and also inhibited chemotaxis. These observations indicate that intact mitochondrial function is required to sustain some neutrophil functions, but not for the rapid initiation of the respiratory burst or phagocytosis. Loss of mitochondrial membrane potential was a very early marker for commitment of neutrophils into apoptosis and preceded the appearance of phosphatidylserine on the cell surface. However, inhibition of mitochondrial function did not accelerate the rate of neutrophil apoptosis. These data shed important insights into the hitherto unrecognized importance of mitochondria in the function of neutrophils during infection and inflammation.
Modulation of HLA-A*0201-Restricted T Cell Responses by Natural Polymorphism in the IE1315–324 Epitope of Human Cytomegalovirus
Authors: Prod’homme Virginie , Retière Christelle , Imbert-Marcille Berthe-Marie , Bonneville Marc , Hallet Marie-Martine 
Published: April 2014

Abstract
Cytotoxic T lymphocytes play a central role in the control of persistent human CMV (HCMV) infection and reactivation. In healthy virus carriers, the specific CD8+ CTL response is almost entirely directed against the virion tegument protein pp65 and/or the 72-kDa major immediate early protein, IE1. Studies that included a large panel of HCMV+ donors suggested that immunorelevance of pp65 and IE1 was directly related with individual HLA haplotype difference. Nevertheless, there are no data on the incidence of HCMV natural polymorphism on virus-specific CTL responses. To assess the impact of IE1 polymorphism on CTL response, we have sequenced in 103 clinical isolates the DNA region corresponding to IE1315–324, an immunodominant epitope presented by HLA-A*0201 molecules. Seven peptidic variants were found with extensive difference in their frequencies. The response of four HLA-A*0201-restricted anti-IE1 T lymphocyte clones, which were previously generated from one donor against autologous B lymphoblastoid cells expressing a recombinant clinical variant of IE1, was then evaluated using target cells loaded with mutant synthetic peptides or expressing rIE1 variants. One of four clones, which have been sorted 19 times among 22 clones targeted against IE1315–324, recognized six of the seven tested variant epitopes. All three other clones showed distinct reactivity patterns to target cells loaded with the different mutant peptides or expressing IE1 variants. Therefore, in the HLA-A2 context, clonal expansions of anti-IE1 memory CTLs may confer a protection against HCMV successive infections and reactivations by killing cells presenting most of the naturally occurring IE1315–324 epitope variants.
IL-13 Is Sufficient for Respiratory Syncytial Virus G Glycoprotein-Induced Eosinophilia After Respiratory Syncytial Virus Challenge
Authors: Johnson Teresa R. , Parker Robert A. , Johnson Joyce E. , Graham Barney S. 
Published: April 2014

Abstract
Although well studied in settings of helminth infection and allergen sensitization, the combined contributions of IL-4 and IL-13 and their signaling pathways in models of viral pathogenesis have not been reported. Using a murine model of respiratory syncytial virus (RSV) infection, we evaluated the contribution of IL-13, alone and in conjunction with IL-4, during immunization with recombinant vaccinia virus expressing RSV G glycoprotein (vvGs) or with formalin-inactivated RSV (FI-RSV). We showed that both IL-4 and IL-13 activity must be inhibited to modulate G-specific responses resulting in severe RSV-induced disease. Inhibition of IL-4 or IL-13 activity alone had minimal impact on disease in vvGs-immunized mice. However, treatment of IL-4-deficient mice with IL-13Ra during vvGs immunization reduced IL-5, IL-13, and eotaxin production and pulmonary eosinophilia after RSV challenge. In contrast, FI-RSV-induced immune responses were diminished when either IL-4 or IL-13 activity was blocked. After RSV challenge, these type 2 T cell responses were also diminished in vvGs-primed IL-4Rα-deficient mice. Our data suggest that secreted vvGs uses mechanisms requiring signaling through the IL-4Rα-chain by either IL-4 or IL-13 for induction of eosinophilia and is the first description of the relative contributions of IL-4, IL-13, and their receptors in viral pathogenesis.
Persistence and Turnover of Antigen-Specific CD4 T Cells During Chronic Tuberculosis Infection in the Mouse
Authors: Winslow Gary M. , Roberts Alan D. , Blackman Marcia A. , Woodland David L. 
Published: April 2014

Abstract
CD4 T cells are critical for resistance to Mycobacterium tuberculosis infection, but how effective T cell responses are maintained during chronic infection is not well understood. To address this question we examined the CD4 T cell response to a peptide from ESAT-6 during tuberculosis infection in the mouse. The ESAT-61–20/IAb-specific CD4 T cell response in the lungs, mediastinal lymph nodes, and spleen reached maxima 3–4 wk postinfection, when the bacteria came under the control of the immune response. Once chronic infection was established, the relative frequencies of Ag-specific CD4 T cells were maintained at nearly constant levels for at least 160 days. ESAT-61–20/IAb-specific CD4 T cells that responded in vitro expressed activation markers characteristic of chronically activated effector cells and used a limited Vβ repertoire that was clonally stable in vivo for at least 12 wk. 5-Bromo-2-deoxyuridine incorporation studies indicated a relatively high rate of cell division among both total CD4 and ESAT-61–20/IAb-specific CD4 T cells during acute infection, but the degree of 5-bromo-2-deoxyuridine incorporation by both the CD4 T cells and the Ag-specific cells declined at least 3-fold during chronic infection. The data indicate that the peripheral ESAT-61–20/IAb-specific CD4 T cell response to M. tuberculosis is characterized during the acute phase of infection by a period of extensive proliferation, but once bacterial control is achieved, this is followed during chronic infection by an extended containment phase that is associated with a persistent response of activated, yet more slowly proliferating, T cells.