bluuebunny/crossref_metadata_2025_split huggingface dataset:
Induction of Phosphorylation and Intracellular Association of CC Chemokine Receptor 5 and Focal Adhesion Kinase in Primary Human CD4+ T Cells by Macrophage-Tropic HIV Envelope
Authors: Cicala Claudia , Arthos James , Ruiz Margaret , Vaccarezza Mauro , Rubbert Andrea , Riva Agostino , Wildt Kathryn , Cohen Oren , Fauci Anthony S. 
Published: January 2023

Abstract
Binding of HIV-1 envelope glycoproteins to the surface of a CD4+ cell transduces intracellular signals through the primary envelope receptor, CD4, and/or the envelope coreceptor, a seven-transmembrane chemokine receptor. Macrophage-tropic strains of HIV-1 preferentially use CCR5 as an entry coreceptor, whereas T cell-tropic strains use CXC chemokine receptor-4 for entry. Intracellular signals transduced by HIV-1 envelope may have immunopathogenic consequences, including anergy, syncytium formation, apoptosis, and inappropriate cell trafficking. We demonstrate here that a recombinant envelope protein derived from an M-tropic isolate of HIV-1 can transduce CD4-dependent as well as CCR5-dependent intracellular signals in primary human CD4+ T cells. Novel HIV-induced intracellular signals that were identified include tyrosine phosphorylation of focal adhesion kinase (FAK) and CCR5, which are involved in cell adhesion and chemotaxis, respectively. HIV envelope-induced cellular association of FAK and CCR5 was also demonstrated, suggesting that ligation of CD4 and CCR5 leads to the formation of an activation complex composed of FAK and CCR5. Activation of this signaling pathway by HIV-1 envelope may be an important pathogenic mechanism of dysregulated cellular activation and trafficking during HIV infection.
IL-5 Increases Expression of 5-Lipoxygenase-Activating Protein and Translocates 5-Lipoxygenase to the Nucleus in Human Blood Eosinophils
Authors: Cowburn Andrew S. , Holgate Stephen T. , Sampson Anthony P. 
Published: January 2023

Abstract
Cysteinyl-leukotrienes are potent bronchoconstrictor mediators synthesized by the 5-lipoxygenase (5-LO) pathway. Eosinophilopoietic cytokines such as IL-5 enhance cysteinyl-leukotriene synthesis in eosinophils in vitro, mimicking changes in eosinophils from asthmatic patients, but the mechanism is unknown. We hypothesized that IL-5 induces the expression of 5-LO and/or its activating protein FLAP in eosinophils, and that this might be modulated by anti-inflammatory corticosteroids. Compared with control cultures, IL-5 increased the proportion of normal blood eosinophils immunostaining for FLAP (65 ± 4 vs 34 ± 4%; p &lt; 0.0001), enhanced immunoblot levels of FLAP by 51 ± 14% (p = 0.03), and quadrupled ionophore-stimulated leukotriene C4 synthesis from 5.7 to 20.8 ng/106 cells (p &lt; 0.02). IL-5 effects persisted for 24 h and were abolished by cycloheximide and actinomycin D. The proportion of FLAP+ eosinophils was also increased by dexamethasone (p &lt; 0.0001). Neither IL-5 nor dexamethasone altered 5-LO expression, but IL-5 significantly increased 5-LO immunofluorescence localizing to eosinophil nuclei. Compared with normal subjects, allergic asthmatic patients had a greater proportion of circulating FLAP+ eosinophils (46 ± 6 vs 27 ± 3%; p &lt; 0.03) and a smaller IL-5-induced increase in FLAP immunoreactivity (p &lt; 0.05). Thus, IL-5 increases FLAP expression and translocates 5-LO to the nucleus in normal blood eosinophils in vitro. This is associated with an enhanced capacity for cysteinyl-leukotriene synthesis and mimics in vivo increases in FLAP expression in eosinophils from allergic asthmatics.
Cutting Edge: SLP-76 Cooperativity with FYB/FYN-T in the Up-Regulation of TCR-Driven IL-2 Transcription Requires SLP-76 Binding to FYB at Tyr595 and Tyr651
Authors: Geng Liping , Raab Monika , Rudd Christopher E. 
Published: January 2023

Abstract
SLP-76 (Src homology (SH) 2-domain-containing leukocyte protein of 76 kDa) and FYB/SLAP (FYN-T-binding protein/SLP-76-associated protein) are two hemopoietic cell-specific adaptor proteins downstream of TCR-activated protein tyrosine kinases. SLP-76 has been implicated as an essential component in T cell signaling. FYB is selectively phosphorylated by FYN-T, providing a template for the recruitment of FYN-T and SLP-76 SH2 domains. Coexpression of FYN-T, FYB, and SLP-76 can synergistically up-regulate IL-2 production in T cells upon TCR ligation. In this report, we show that two tyrosines, Tyr595 and Tyr651, of FYB are major sites of phosphorylation by FYN-T and mediate binding to SLP-76 in Jurkat T cells. Furthermore, the synergistic up-regulation of IL-2 promoter activity in the FYN-T-FYB-SLP-76 pathway is contingent upon the interaction between FYB and SLP-76, but not the interaction between FYB and FYN-T. These observations define a pathway by which SLP-76 interacts with downstream components in the up-regulation of T cell cytokine production.
Sustained Activation of the Raf-MEK-ERK Pathway Elicits Cytokine Unresponsiveness in T Cells
Authors: Chen Dan , Heath Victoria , O’Garra Anne , Johnston James , McMahon Martin 
Published: January 2023

AbstractActivation of T cells via the TCR and other costimulatory receptors triggers a number of signaling cascades. Among them, the Ras-activated Raf-mitogen-activated protein/extracellular signal-related kinase (ERK) kinase (MEK)-ERK signaling cascade has been demonstrated to be crucial for both T cell development and activation. It has previously been demonstrated that high doses of Ag or anti-CD3 mAb are able to induce in T cells a nonresponsive state to subsequent treatment with cytokines such as IL-2. The precise biochemical mechanisms underlying this effect are not fully characterized. In this study, we demonstrate that cytokine nonresponsiveness is accompanied by the induction of the cyclin-dependent kinase inhibitor p21Cip1 that is mediated, at least in part, by the activation of the Raf-MEK-ERK pathway. Furthermore, we demonstrate that selective activation of the Raf-MEK-ERK signaling pathway in T cells is sufficient to induce cytokine nonresponsiveness in both a T cell clone and naive primary T cells. In this case, nonresponsiveness is accompanied by the induction of p21Cip1 and the prevention of p27Kip1 down-regulation, leading to inhibition of cyclin E/cyclin-dependent kinase 2 activity. These data suggest that anti-CD3 mAb-induced cytokine nonresponsiveness may be a consequence of hyperactivation of the Raf-MEK-ERK pathway, leading to alterations in the expression of key cell cycle regulators. These observations may provide a novel insight into the mechanisms of induction of peripheral tolerance.
Protein Kinase Cθ Cooperates with Calcineurin to Induce Fas Ligand Expression During Activation-Induced T Cell Death
Authors: Villalba Martin , Kasibhatla Shailaja , Genestier Laurent , Mahboubi Artin , Green Douglas R. , Altman Amnon 
Published: January 2023

Abstract
Activation-induced cell death is mediated by the TCR-induced expression of the Fas ligand (FasL) on the surface of T cells, followed by binding to its receptor Fas. FasL expression is induced by stimulating T cells with a combination of phorbol ester and Ca2+ ionophore, implicating a role for protein kinase C (PKC) in this process. However, the precise mechanisms that regulate FasL expression, including the contribution of distinct T cell-expressed PKC isoforms, are poorly understood. Herein, we report that PKCθ, a Ca2+-independent PKC isoform that we have previously isolated as a PKC enzyme selectively expressed in T cells, plays an important role in these processes. A constitutively active PKCθ mutant preferentially induced FasL expression and activated the corresponding gene promoter; conversely, a dominant-negative PKCθ mutant blocked FasL expression induced by anti-CD3 or PMA plus ionomycin stimulation. Furthermore, PKCθ synergized with calcineurin to provide a potent stimulus for FasL promoter activation. Full activation of the promoter required its binding sites for the transcription factors NF-AT, AP-1, and NF-κB. The biological significance of these findings is implicated by the finding that rottlerin, a selective PKCθ inhibitor, blocked FasL induction by anti-CD3 or PMA plus ionomycin stimulation and, consequently, protected human Jurkat T cells and the mouse T cell hybridoma A1.1 from activation-induced cell death.
Augmentation of an Antitumor CTL Response In Vivo by Inhibition of Suppressor Macrophage Nitric Oxide
Authors: Medot-Pirenne Marianne , Heilman Michelle J. , Saxena Malinee , McDermott Patricia E. , Mills Charles D. 
Published: January 2023

AbstractEvidence is provided that inhibition of macrophage NO production can augment in vivo CTL responses. Specifically, administration of NG-monomethyl-l-arginine (NGMMA) via osmotic pumps increases the tumor-specific CTL response against the P815 mastocytoma in the peritoneal cavity of preimmunized mice. Both the magnitude and duration of the CTL response were increased. That the augmented CTL response resulted from inhibition of the NO synthase pathway is supported by the finding that macrophage NO production from NGMMA-treated mice was reduced. Also, in vitro inhibition of NO production by peritoneal exudate cells from P815 tumor-challenged mice augmented the secondary CTL response observed. Cell proliferation was augmented by NGMMA in these cultures, suggesting that macrophage NO may suppress CTL by inhibiting clonal expansion. NO-mediated inhibition was observed in vivo in this experimental system, even though the CTL response is not suppressed, in that tumor rejection occurs. Therefore, the present results are consistent with the conclusion that macrophage NO-mediated inhibition of the CTL response is a side effect of activating macrophages rather than resulting from the action of a distinct subset of what have long been termed suppressor macrophages. Most important, the results indicate that NO-mediated suppressor macrophage activity can be an important CTL immunoregulatory element in vivo.
Proliferation of Bone Marrow Pro-B Cells Is Dependent on Stimulation by the Pituitary/Thyroid Axis
Authors: Foster Melanie P. , Montecino-Rodriguez Encarnacion , Dorshkind Kenneth 
Published: January 2023

AbstractThe frequency and absolute number of pro-B, pre-B, and B cells in the bone marrow of the hypothyroid strain of mice are significantly reduced compared with those of their normal littermates. To investigate why this is the case, various B cell developmental processes were examined in the thyroid hormone-deficient mice. These studies revealed that the frequency of pro-B cells in the S-G2/M phase of the cell cycle was significantly reduced in hypothyroid mice. That thyroid hormone deficiency was responsible for this proliferation defect was established by demonstrating that treatment of hypothyroid mice with thyroxine resulted in a specific increase in the frequency and total number of cycling pro-B cells. The latter effect was paralleled by increases in the frequency and number of bone marrow B lineage cells. Additional in vitro experiments revealed that at least some thyroid hormone effects were directly mediated on the bone marrow. Taken together, these data demonstrate that thyroid hormones are required for normal B cell production in the bone marrow through regulation of pro-B cell proliferation and establish a role for the pituitary/thyroid axis in B cell development.
Requirement for Stat5 in Thymic Stromal Lymphopoietin-Mediated Signal Transduction
Authors: Isaksen Deborah E. , Baumann Heinz , Trobridge Patty A. , Farr Andrew G. , Levin Steven D. , Ziegler Steven F. 
Published: January 2023

Abstract
Thymic stromal lymphopoietin (TSLP) is a newly identified cytokine that uniquely promotes B lymphopoiesis to the B220+/IgM+ immature B cell stage. In addition, TSLP shares many biological properties with the related cytokine IL-7. This can be explained by the finding that the receptor complexes for TSLP and IL-7 both contain the IL-7R α-chain; IL-7Rα is paired with the common γ-chain (γc) in the IL-7 receptor complex and the unique TSLP-R chain in the TSLP receptor complex. Although TSLP and IL-7 both induce tyrosine phosphorylation of the transcription factor Stat5, only IL-7-mediated signal transduction could be associated with activation of Janus family kinases (Jaks). Because Stat5 phosphorylation following cytokine stimulation is generally mediated by Jaks, the lack of Jak activation after TSLP treatment suggested the possibility that tyrosine-phosphorylated Stat5 may be nonfunctional. Herein, we demonstrate that TSLP induces a functional Stat5 transcription factor in that TSLP stimulation results in Stat5-DNA complex formation and transcription of the Stat5-responsive gene CIS. We also show that the TSLP receptor complex is functionally reconstituted using TSLP-R and IL-7Rα and that TSLP-mediated signal transduction requires Stat5. Moreover, TSLP-mediated signaling is inhibited by suppressor of cytokine signaling (SOCS)-1 and a kinase-deficient version of Tec but not by kinase-deficient forms of Jak1 and Jak2.
High Affinity IgG Receptor Activation of Src Family Kinases Is Required for Modulation of the Shc-Grb2-Sos Complex and the Downstream Activation of the Nicotinamide Adenine Dinucleotide Phosphate (Reduced) Oxidase
Authors: Park Rae-Kil , Erdreich-Epstein Anat , Liu Ming , Izadi Kayvon D. , Durden Donald L. 
Published: January 2023

AbstractWe used the U937 cell line to examine the modulation of adaptor protein interactions (Shc, Grb2, and Cbl) after high affinity IgG receptor (FcγRI) cross-linking, leading to the formation of the Grb2-Sos complex, the activation of Ras, and the regulation of the respiratory burst. Cross-linking of FcγRI induced the conversion of GDP-Ras to GTP-Ras reaching a maximum 5 min after stimulation. Concomitant with Ras activation, Sos underwent an electrophoretic mobility shift and the Sos-Grb2 association was increased (6-fold). The Grb2-Sos complex was present only in the membrane fraction and was augmented after FcγRI stimulation. Tyrosine-phosphorylated Shc, mainly the p52 isoform, was observed to transiently onload to the membrane Grb2-Sos complex on FcγRI stimulation. Cross-linking of FcγRI induces the tyrosine phosphorylation of Cbl, which forms a complex with Grb2 and Shc via the Cbl C terminus. Kinetic experiments confirm that Cbl-Grb2 is relatively stable, whereas Grb2-Sos, Grb2-Shc, and Cbl-Shc interactions are highly inducible. The Src family tyrosine kinase inhibitor, PP1, was shown to completely inhibit Shc tyrosine phosphorylation, the Shc-Grb2 interaction, and the FcγR-induced respiratory burst. Our results provide the first evidence that the upstream activation of Src kinases is required for the modulation of the Shc-Grb2 interaction and the myeloid NADPH oxidase response.
Recruitment of CREB-Binding Protein by PU.1, IFN-Regulatory Factor-1, and the IFN Consensus Sequence-Binding Protein Is Necessary for IFN-γ-Induced p67phoxand gp91phoxExpression
Authors: Eklund Elizabeth A. , Kakar Renu 
Published: January 2023

AbstractActivation of the phagocyte respiratory burst oxidase requires interaction between the oxidase components p47phox, p67phox, p22phox, and gp91phox. IFN-γ induces transcription of the genes encoding p67phox (the NCF2 gene) and gp91phox (the CYBB gene) during monocyte differentiation, and also in mature monocytes. In these studies, we identify an NCF2 cis element, necessary for IFN-γ-induced p67phox expression, and determine that this element is activated by cooperation between the transcription factors PU.1, IFN regulatory factor 1 (IRF1), and the IFN consensus-binding protein (ICSBP). Previously, we identified a CYBB cis element, necessary for IFN-γ-induced gp91phox expression, and also activated by this transcription factor combination. In these investigations, we determine that recruitment of a coactivator protein, CBP (the CREBbinding protein), to the CYBB or NCF2 promoter is the molecular mechanism of transcriptional activation by PU.1, IRF1, and ICSBP. Also, we determine that the multiprotein interaction of CBP with PU.1, IRF1, and ICSBP requires either the CYBB- or NCF2--binding site. Because IFN-γ induces simultaneous expression of p67phox and gp91phox, these investigations identify a molecular event that coordinates oxidase gene transcription during the inflammatory response. Also, these investigations identify CBP recruitment by cooperation between PU.1, IRF1, and ICSBP as a novel molecular mechanism for IFN-γ-induced activation of myeloid genes that are involved in the system of host defense.
Lipoteichoic Acid inhibits Lipopolysaccharide-Induced Adhesion Molecule Expression and IL-8 Release in Human Lung Microvascular Endothelial Cells
Authors: Blease Kate , Chen Yan , Hellewell Paul G. , Burke-Gaffney Anne 
Published: January 2023

AbstractCell adhesion molecule expression (CAM) and IL-8 release in lung microvascular endothelium facilitate neutrophil accumulation in the lung. This study investigated the effects of lipoteichoic acid (LTA), a cell wall component of Gram-positive bacteria, alone and with LPS or TNF-α, on CAM expression and IL-8 release in human lung microvascular endothelial cells (HLMVEC). The concentration-dependent effects of Staphylococcus aureus (S. aureus) LTA (0.3–30 μg/ml) on ICAM-1 and E-selectin expression and IL-8 release were bell shaped. Streptococcus pyogenes (S. pyogenes) LTA had no effect on CAM expression, but caused a concentration-dependent increase in IL-8 release. S. aureus and S. pyogenes LTA (30 μg/ml) abolished LPS-induced CAM expression, and S. aureus LTA reduced LPS-induced IL-8 release. In contrast, the effects of S. aureus LTA with TNF-α on CAM expression and IL-8 release were additive. Inhibitory effects of LTA were not due to decreased HLMVEC viability, as assessed by ethidium homodimer-1 uptake. Changes in neutrophil adhesion to HLMVEC paralleled changes in CAM expression. Using RT-PCR to assess mRNA levels, S. aureus LTA (3 μg/ml) caused a protein synthesis-dependent reduction (75%) in LPS-induced IL-8 mRNA and decreased the IL-8 mRNA half-life from &gt;6 h with LPS to ∼2 h. These results suggest that mechanisms exist to prevent excessive endothelial cell activation in the presence of high concentrations of bacterial products. However, inhibition of HLMVEC CAM expression and IL-8 release ultimately may contribute to decreased neutrophil accumulation, persistence of bacteria in the lung, and increased severity of infection.
Peptides of Human Thyroglobulin Reactive with Sera of Patients with Autoimmune Thyroid Disease
Authors: Saboori Ali M. , Rose Noel R. , Yuhasz Stacieann C. , Amzel L. Mario , Burek C. Lynne 
Published: January 2023

AbstractAutoantibodies to thyroglobulin (Tg) are a prominent feature of the two autoimmune thyroid diseases, chronic lymphocytic (Hashimoto’s) thyroiditis and Graves’ disease. Similar autoantibodies are found in the serum of many normal individuals without evidence of thyroid disease. Previous studies have indicated that patients with autoimmune thyroid disease recognize epitopes of Tg which are not usually recognized by normal individuals. The goal of this investigation was to identify peptide fragments of Tg bearing these disease-associated epitopes. For this purpose, we utilized a panel of mAbs that bind to different epitopes of the Tg molecule. One of these mAbs (137C1) reacted with an epitope that was also recognized by the sera of patients with autoimmune thyroiditis. In the present study, we show that two peptides (15 and 23 kDa) that reacted with mAb 137C1 are located in different parts of the Tg molecule. Each peptide inhibited the binding of mAb 137C1 to the other peptide and to the intact Tg, indicating that the same epitope was represented on the two peptides. Loops and helices of the secondary structure of the two peptides might be involved in the conformational epitope recognized by mAb 137C1. A striking finding of this study is that two apparently unrelated fragments of the Tg molecule bind to the same mAb. These findings may have important ramifications with regard to epitope spread and the progression of the autoimmune response to disease.
Identification of an IL-10-Producing HLA-DR-Negative Monocyte Subset in the Malignant Ascites of Patients with Ovarian Carcinoma That Inhibits Cytokine Protein Expression and Proliferation of Autologous T Cells
Authors: Loercher Amy E. , Nash Micheal A. , Kavanagh John J. , Platsoucas Chris D. , Freedman Ralph S. 
Published: January 2023

AbstractA newly described subset of monocytes has been identified in peritoneal exudate cells (PEC) from the malignant ascites from patients with ovarian cancer. These cells were characterized by the production of IL-10 and TGF-β2, but not IL-12, IL-1α, or TNF-α, and they expressed CD14, CD16, and CD54, but not HLA-DR, CD80, CD86, CD11a, CD11b, or CD25 cell surface Ags. Since this subset of monocytes could affect the modulation of tumor immune responses in vivo, studies were undertaken to determine their effect on the activation and proliferation of autologous T cells from the peritoneal cavity of patients with ovarian carcinoma. Expression of cytokine-specific transcripts in T cells was determined by RT-PCR. Transcripts for the following cytokines were detected in patient specimens that also contained the IL-10-producing monocytes IL-2 (12 of 17 specimens), GM-CSF (9 of 17 specimens), IFN-γ (6 of 17 specimens), and TNF-α (4 of 17 specimens). Cytokine production by T cells was determined by intracellular flow cytometry and by ELISA. IL-2 and IFN-γ proteins, unlike their transcripts, were detected only in specimens that lacked IL-10-producing monocytes. IL-10-producing monocytes cocultured with autologous T cells inhibited the proliferation of the T cells in response to PHA. However, T cells cocultured with PEC from which the IL-10-producing monocytes had been removed did not inhibit T cell proliferation. Moreover, the inhibition of T cell proliferation by IL-10-producing monocytes could be reversed by adding neutralizing Abs to both IL-10R and TGF-β2. These results suggest that this subset of monocytes may modulate immune responses by inhibiting T cell proliferation and cytokine protein production.
Essential Role for Both CD80 and CD86 Costimulation, But Not CD40 Interactions, in Allergen-Induced Th2 Cytokine Production from Asthmatic Bronchial Tissue: Role for αβ, But Not γδ, T Cells
Authors: Jaffar Zeina H. , Stanciu Luminita , Pandit Anita , Lordan James , Holgate Stephen T. , Roberts Kevan 
Published: January 2023

AbstractCD80 and CD86 interact with CD28 and deliver costimulatory signals required for T cell activation. We demonstrate that ex vivo allergen stimulation of bronchial biopsy tissue from mild atopic asthmatic, but not atopic nonasthmatic, subjects induced production of IL-5, IL-4, and IL-13. Explants from both study groups did not produce IFN-γ, but secreted the chemokine RANTES without any overt stimulation. In addition to allergen, stimulation of asthmatic explants with mAbs to CD3 and TCR-αβ but not TCR-γδ induced IL-5 secretion. Allergen-induced IL-5 and IL-13 production by the asthmatic tissue was inhibited by anti-CD80 and, to a lesser extent, by anti-CD86 mAbs. In contrast, the production of these cytokines by PBMCs was not affected by mAbs to CD80, was inhibited by anti-CD86, and was strongly attenuated in the presence of both Abs. FACS analysis revealed that stimulated asthmatic bronchial tissue was comprised of CD4+ T cells that expressed surface CD28 (75.3%) but little CTLA-4 (4.0%). Neutralizing mAbs to CD40 ligand had no effect on the cytokine levels produced by asthmatic tissue or PBMCs. Collectively, these findings suggest that allergen-specific αβ T cells are resident in asthmatic bronchial tissue and demonstrate that costimulation by both CD80 and CD86 is essential for allergen-induced cytokine production. In contrast, CD86 appears to be the principal costimulatory molecule required in PBMC responses. Attenuation of type 2 αβ T cell responses in the bronchial mucosa by blocking these costimulatory molecules may be of therapeutic potential in asthma.