bluuebunny/crossref_metadata_2025_split huggingface dataset:
Autocrine Regulation of IL-21 Production in Human T Lymphocytes
Authors: Caprioli Flavio , Sarra Massimiliano , Caruso Roberta , Stolfi Carmine , Fina Daniele , Sica Giuseppe , MacDonald Thomas T. , Pallone Francesco , Monteleone Giovanni 
Published: April 2014

Abstract
IL-21 has pathologic function in immune-inflammatory diseases. IL-21 mediates its functions through a heterodimeric receptor, composed of a specific subunit, termed IL-21R, and the common γ-chain. IL-21 is mostly produced by CD4+ T cells, but molecular mechanisms that regulate IL-21 synthesis are not fully understood. The fact that CD4+ T cells express high levels of IL-21R and are capable of functionally responding to IL-21 raises the possibility that IL-21 may regulate its own production. We here show that IL-21 enhances IL-21 RNA and protein expression in human peripheral blood CD3+ T cells in a dose- and time-dependent fashion. Additionally, both IL-7 and IL-15, but not IL-4, induce IL-21, thus suggesting that common γ-chain signals are not sufficient to promote IL-21 synthesis. Analysis of molecular mechanisms underlying IL-21 induction reveals that IL-21 activates Stat3 and enhances its recruitment to IL-21 gene promoter. Pharmacologic inhibition and knockdown of Stat3 by small interference RNA largely prevent IL-21 induction in IL-21-treated cells. Consistently, IL-21 is inducible in T cells by IL-6, another cytokine that activates Stat3. Finally, we show that IL-21 positively regulates its own expression in human intestinal CD3+ lamina propria lymphocytes, and blockade of endogenous IL-21 in cultures of CD3+ lamina propria lymphocytes isolated from patients with Crohn’s disease, a chronic inflammatory bowel disease characterized by high IL-21, down-regulates Stat3 activation and IL-21 expression. These data suggest the existence of a positive autocrine loop that could help to amplify and stabilize IL-21-driven, T cell-mediated responses.
Cyclin-Dependent Kinase Inhibitors Block Leukocyte Adhesion and Migration
Authors: Liu Li , Schwartz Barbara , Tsubota Yoshiaki , Raines Elaine , Kiyokawa Hiroaki , Yonekawa Karyn , Harlan John M. , Schnapp Lynn M. 
Published: April 2014

Abstract
Leukocyte trafficking is a tightly regulated process essential for an appropriate inflammatory response. We now report a new adhesion pathway that allows unstimulated leukocytes to adhere to and migrate through exposed endothelial matrix or high-density ligand, a process we have termed ligand-induced adhesion. This ligand-induced adhesion is integrin mediated, but in contrast to phorbol ester-stimulated adhesion, it is not dependent on the small GTPase Rap-1 activity. Instead, we show a critical role for cyclin-dependent kinase (Cdk) 4 in ligand-induced adhesion by three independent lines of evidence: inhibition by pharmacological inhibitors of Cdk, inhibition by dominant-negative construct of Cdk4, and inhibition by Cdk4 small interfering RNA. The major substrate of Cdk4, Rb, is not required for ligand-induced adhesion, suggesting the involvement of a novel Cdk4 substrate. We also demonstrate that Cdk4−/− mice have impaired recruitment of lymphocytes to the lung following injury. The finding that Cdk inhibitors can block leukocyte adhesion and migration may expand the clinical indications for this emerging class of therapeutics.
Sphingosine 1-Phosphate 1 and TLR4 Mediate IFN-β Expression in Human Gingival Epithelial Cells
Authors: Eskan Mehmet A. , Rose Beate G. , Benakanakere Manjunatha R. , Lee Menq-Jer , Kinane Denis F. 
Published: April 2014

Abstract
IFN-β production is a critical step in human innate immune responses and is primarily controlled at the transcription level by highly ordered mechanisms. IFN-β can be induced by pattern-recognition receptors such as the TLR4. S1P1 is a G protein-coupled receptor, which has a high affinity for sphingosine 1-phosphate (S1P). Although many of the receptors and signaling pathways leading to the expression of IFN-β have been identified and characterized, it is still unclear how IFN-β is regulated in primary human gingival epithelial cells (HGECs). In this study, we demonstrate that S1P1 and TLR4, acting in unison, play an important role in IFN-β expression at the protein and mRNA level in HGECs. We demonstrate that the expression of both IFN-β and IFN-inducible protein-10 (CXCL-10) is significantly up-regulated by LPS and S1P or LPS and a specific S1P1 agonist. This enhanced innate immune response is attenuated in HGECs by small interfering RNA knockdown of either TLR4 or S1P1. Moreover, we show that triggering of TLR4 results in the increased expression of S1P1 receptors. Furthermore, we found that IFN-regulatory factor 3 activation was maximized by LPS and S1P through PI3K. Our data show that triggering TLR4 increases S1P1, such that both TLR4 and S1P1 acting through PI3K enhancement of IFN-regulatory factor 3 activation increase IFN-β expression in epithelial cells. The functional association between TLR4 and the S1P1 receptor demonstrates a novel mechanism in the regulation of IFN-β and CXCL-10 in human primary gingival epithelial cells.
Cyclooxygenase-2 Deficiency Enhances Th2 Immune Responses and Impairs Neutrophil Recruitment in Hepatic Ischemia/Reperfusion Injury
Authors: Hamada Takashi , Tsuchihashi Seiichiro , Avanesyan Armine , Duarte Sergio , Moore Carolina , Busuttil Ronald W. , Coito Ana J. 
Published: April 2014

AbstractCyclooxygenase-2 (COX-2) is a prostanoid-synthesizing enzyme that is critically implicated in a variety of pathophysiological processes. Using a COX-2-deficient mouse model, we present data that suggest that COX-2 has an active role in liver ischemia/reperfusion (I/R) injury. We demonstrate that COX-2-deficient mice had a significant reduction in liver damage after I/R insult. The inability of COX-2−/− to elaborate COX-2 products favored a Th2-type response in these mice. COX-2−/− livers after I/R injury showed significantly decreased levels of IL-2, as well as IL-12, a cytokine known to have a central role in Th1 effector cell differentiation. Moreover, such livers expressed enhanced levels of the anti-inflammatory cytokine IL-10, shifting the balance in favor of a Th2 response in COX-2-deficient mice. The lack of COX-2 expression resulted in decreased levels of CXCL2, a neutrophil-activating chemokine, reduced infiltration of MMP-9-positive neutrophils, and impaired late macrophage activation in livers after I/R injury. Additionally, Bcl-2 and Bcl-xL were normally expressed in COX-2−/− livers after injury, whereas respective wild-type controls were almost depleted of these two inhibitors of cell death. In contrast, caspase-3 activation and TUNEL-positive cells were depressed in COX-2−/− livers. Therefore, our data support the concept that COX-2 is involved in the pathogenic events occurring in liver I/R injury. The data also suggest that potential valuable therapeutic approaches in liver I/R injury may result from further studies aimed at identifying specific COX-2-derived prostanoid pathways.
Polarized Localization of Epithelial CXCL11 in Chronic Obstructive Pulmonary Disease and Mechanisms of T Cell Egression
Authors: Porter Joanna C. , Falzon Mary , Hall Alan 
Published: April 2014

Abstract
The exit of lymphocytes from the interstitium of the lung, across the bronchial epithelium and into the airway lumen, is known as egression, or luminal clearance. Egression is important for immune surveillance and the resolution of inflammation, but the mechanisms involved are unknown. We show that egression of human T cells across the bronchial epithelium is a multistep process, driven in part by a polarized transepithelial gradient of CXCL11 that is up-regulated in patients with chronic obstructive airways disease. Previous studies have shown that T cells can migrate across a disrupted bronchial epithelium, but we provide evidence that egression does not require epithelial injury, and can take place across an intact epithelial barrier. After negotiating the extracellular matrix, the T cell adheres to the basal surface of the bronchial epithelial cell using α4 and leukocyte function associated-1 integrins before crossing the epithelium in an leukocyte function associated-1-dependent way. We demonstrate an egression-dependent decrease in transepithelial resistance across the epithelium without gross alteration in tight-junction proteins. The process of egression has been relatively overlooked when considering the control of leukocyte trafficking in the lung and other epithelial organs. This study highlights the role of the respiratory epithelium in the trafficking of T lymphocytes from the pulmonary interstitium and into the large airways, during the onset and resolution of pulmonary inflammation.
Histone Deimination As a Response to Inflammatory Stimuli in Neutrophils
Authors: Neeli Indira , Khan Salar N. , Radic Marko 
Published: April 2014

Abstract
Posttranslational modifications, such as the deimination of arginine to citrulline by peptidyl arginine deiminase (PAD4), change protein structure and function. For autoantigens, covalent modifications represent a mechanism to sidestep tolerance and stimulate autoimmunity. To examine conditions leading to histone deimination in neutrophils, we used Abs that detect citrullines in the N terminus of histone H3. Deimination was investigated in human neutrophils and HL-60 cells differentiated into granulocytes. We observed rapid and robust H3 deimination in HL-60 cells exposed to LPS, TNF, lipoteichoic acid, f-MLP, or hydrogen peroxide, which are stimuli that activate neutrophils. Importantly, we also observed H3 deimination in human neutrophils exposed to these stimuli. Citrullinated histones were identified as components of extracellular chromatin traps (NETs) produced by degranulating neutrophils. In contrast, apoptosis proceeded without detectable H3 deimination in HL-60 cells exposed to staurosporine or camptothecin. We conclude that histone deimination in neutrophils is induced in response to inflammatory stimuli and not by treatments that induce apoptosis. Our results further suggest that deiminated histone H3, a covalently modified form of a prominent nuclear autoantigen, is released to the extracellular space as part of the neutrophil response to infections. The possible association of a modified autoantigen with microbial components could, in predisposed individuals, increase the risk of autoimmunity.
Role of Sphingosine 1-Phosphate in the Pathogenesis of Sjögren’s Syndrome
Authors: Sekiguchi Masahiro , Iwasaki Tsuyoshi , Kitano Masayasu , Kuno Hideki , Hashimoto Naoaki , Kawahito Yutaka , Azuma Masayuki , Hla Timothy , Sano Hajime 
Published: April 2014

Abstract
Primary Sjögren’s syndrome (SS) is an autoimmune disease characterized by inflammatory mononuclear cell infiltration and destruction of epithelial cells of lacrimal and salivary glands. Sphingosine 1-phosphate (S1P) and signaling through its receptor S1P1 have been implicated in many critical cellular events including inflammation, cancer, and angiogenesis. This study was undertaken to examine the role of S1P1 signaling in the pathogenesis of primary SS. S1P1 and sphingosine kinase 1, which converts sphingosine to S1P, were detected in the cytoplasm of inflammatory mononuclear cells, vascular endothelial cells, and epithelial cells in all labial salivary glands by immunohistochemistry. The expression of S1P1 in inflammatory mononuclear cells was enhanced in advanced stages of primary SS. S1P enhanced proliferation and IFN-γ production by CD4+ T cells. The enhancing effect of S1P on IFN-γ production by CD4+ T cells was stronger in patients with primary SS than in healthy controls. S1P also enhanced Fas expression and Fas-mediated caspase-3 induction in salivary gland epithelial cells. IL-6 expression was detected in the cytoplasm of inflammatory mononuclear cells and ductal epithelial cells and was enhanced in advanced stages of primary SS. Furthermore, both IFN-γ and S1P augmented IL-6 secretion by salivary gland epithelial cells. These effects of S1P were inhibited by pretreatment of pertussis toxin. Our data reveal that S1P1 signaling may modulate the autoimmune phenotype of primary SS by the action of immune as well as epithelial cells.
Distinct, Specific IL-17- and IL-22-Producing CD4+ T Cell Subsets Contribute to the Human Anti-Mycobacterial Immune Response
Authors: Scriba Thomas J. , Kalsdorf Barbara , Abrahams Deborah-Ann , Isaacs Fatima , Hofmeister Jessica , Black Gillian , Hassan Hisham Y. , Wilkinson Robert J. , Walzl Gerhard , Gelderbloem Sebastian J. , Mahomed Hassan , Hussey Gregory D. , Hanekom Willem A. 
Published: April 2014

Abstract
We investigated whether the proinflammatory T cell cytokines IL-17 and IL-22 are induced by human mycobacterial infection. Remarkably, &gt;20% of specific cytokine-producing CD4+ T cells in peripheral blood of healthy, mycobacteria-exposed adults expressed IL-17 or IL-22. Specific IL-17- and IL-22-producing CD4+ T cells were distinct from each other and from Th1 cytokine-producing cells. These cells had phenotypic characteristics of long-lived central memory cells. In patients with tuberculosis disease, peripheral blood frequencies of these cells were reduced, whereas bronchoalveolar lavage fluid contained higher levels of IL-22 protein compared with healthy controls. IL-17 was not detected in this fluid, which may be due to suppression by Th1 cytokines, as PBMC IL-17 production was inhibited by IFN-γ in vitro. However, Th1 cytokines had no effect on IL-22 production in vitro. Our results imply that the magnitude and complexity of the anti-mycobacterial immune response have historically been underestimated. IL-17- and IL-22-producing CD4+ T cells may play important roles in the human immune response to mycobacteria.
Plasticity of Macrophage Function during Tumor Progression: Regulation by Distinct Molecular Mechanisms
Authors: Biswas Subhra K. , Sica Antonio , Lewis Claire E. 
Published: April 2014

Abstract
Recent studies have shown that macrophages play an important part in both tumor initiation and various key steps in growth and metastasis. These cells show a remarkable degree of plasticity during tumor development with a “switch” in macrophage phenotypes occurring during the course of tumor progression. During chronic inflammation they appear to predispose a given tissue to tumor initiation by the release of factors that promote neoplastic transformation. Following this, their phenotype shifts more toward one that is immunosuppressive and supports tumor growth, angiogenesis, and metastasis. In this review, we discuss the evidence for this plasticity of macrophage functions, the specific signaling mechanisms that may be regulating it, and the new targets for anticancer therapies highlighted by these findings.
Cutting Edge: Activation by Innate Cytokines or Microbial Antigens Can Cause Arrest of Natural Killer T Cell Patrolling of Liver Sinusoids
Authors: Velázquez Peter , Cameron Thomas O. , Kinjo Yuki , Nagarajan Niranjana , Kronenberg Mitchell , Dustin Michael L. 
Published: April 2014

Abstract
Natural killer T (NKT) cells are innate-like lymphocytes that rapidly secrete large amounts of effector cytokines upon activation. Recognition of α-linked glycolipids presented by CD1d leads to the production of IL-4, IFN-γ, or both, while direct activation by the synergistic action of IL-12 and IL-18 leads to IFN-γ production only. We previously reported that in vitro cultured dendritic cells can modulate NKT cell activation and, using intravital fluorescence laser scanning microscopy, we reported that the potent stimulation of NKT cells results in arrest within hepatic sinusoids. In this study, we examine the relationship between murine NKT cell patrolling and activation. We report that NKT cell arrest results from activation driven by limiting doses of a bacteria-derived weak agonist, galacturonic acid-containing glycosphingolipid, or a synthetic agonist, α-galactosyl ceramide. Interestingly, NKT cell arrest also results from IL-12 and IL-18 synergistic activation. Thus, innate cytokines and natural microbial TCR agonists trigger sinusoidal NKT cell arrest and an effector response.
Cutting Edge: Progesterone Regulates IFN-α Production by Plasmacytoid Dendritic Cells
Authors: Hughes Grant C. , Thomas Sunil , Li Chang , Kaja Murali-Krishna , Clark Edward A. 
Published: April 2014

Abstract
Use of the progesterone (Pg) birth control depot medroxyprogesterone acetate (DMPA) increases a woman’s risk for sexually transmitted infection with HIV or HSV-2 via unknown mechanisms. Plasmacytoid dendritic cells (pDCs) are circulating and tissue-resident sentinels capable of making large quantities of IFN-α upon recognizing viruses through TLRs 7 and 9. In this study, we show that Pg inhibits TLR9-induced IFN-α production by human and mouse pDCs and that DMPA impairs TLR9- and virus-induced IFN-α production by pDCs in mice, providing a potential explanation for how DMPA impairs innate antiviral immunity in women. Pg failed to inhibit the Mda-5 pathway of IFN-α induction in dendritic cells, suggesting that Pg regulates select antiviral DC programs. This may occur through selective blockade of IFN regulatory factor-7 activation, a novel steroid action. Thus, through inhibition of TLR-mediated IFN-α production by pDCs, Pg may regulate antiviral immunity.
4-1BB Engagement Costimulates NKT Cell Activation and Exacerbates NKT Cell Ligand-Induced Airway Hyperresponsiveness and Inflammation
Authors: Kim Dong-Hyeon , Chang Woo-Sung , Lee Yoon-Sook , Lee Kyoo-A , Kim Yoon-Keun , Kwon Byoung S. , Kang Chang-Yuil 
Published: April 2014

Abstract
Multiple studies have demonstrated that 4-1BB (CD137), a member of the TNF receptor superfamily, is expressed on several immune cells including activated T cells. However, the expression and the role of 4-1BB on natural killer T (NKT) cells have not been fully characterized. In this study, it was shown that 4-1BB was not expressed on naive NKT cells but was rapidly induced on activated NKT cells by TCR engagement with α-galactosylceramide (α-GalCer). Also, 4-1BB signaling provided by 3H3, an agonistic anti-4-1BB mAb, promoted NKT cell activation resulting in enhanced cytokine production of NKT cells driven by α-GalCer. When NKT cell-driven airway immune responses were evaluated by intranasal administration of α-GalCer, airway hyperresponsiveness (AHR) and lung inflammation were significantly more aggravated in mice treated with 3H3 and α-GalCer than in mice treated with α-GalCer alone. These aggravations were accompanied by up-regulation of IL-4, IL-13, and IFN-γ production. Interestingly, AHR was not developed in IL-4Rα-deficient mice treated with α-GalCer with or without 3H3 but was exacerbated in IFN-γ-deficient mice. Our study suggests that 4-1BB on NKT cells functions as a costimulatory molecule and exacerbates the induction of NKT cell-mediated AHR, which is dependent on the IL-4Rα-mediated pathway.
Inhibition of STAT3 Promotes the Efficacy of Adoptive Transfer Therapy Using Type-1 CTLs by Modulation of the Immunological Microenvironment in a Murine Intracranial Glioma
Authors: Fujita Mitsugu , Zhu Xinmei , Sasaki Kotaro , Ueda Ryo , Low Keri L. , Pollack Ian F. , Okada Hideho 
Published: April 2014

Abstract
A variety of cancers, including malignant gliomas, show aberrant activation of STAT3, which plays a pivotal role in negative regulation of antitumor immunity. We hypothesized that inhibition of STAT3 signals would improve the efficacy of T cell adoptive transfer therapy by reversal of STAT3-induced immunosuppression in a murine GL261 intracranial glioma model. In vitro treatment of GL261 cells with JSI-124, a STAT3 inhibitor, reversed highly phosphorylated status of STAT3. Systemic i.p. administration of JSI-124 in glioma-bearing immunocompetent mice, but not athymic mice, resulted in prolonged survival, suggesting a role of adaptive immunity in the antitumor effect. Furthermore, JSI-124 promoted maturation of tumor-infiltrating CD11c+ dendritic cells and activation of tumor-conditioned cytotoxic T cells, enhanced dendritic cells and GL261 production of CXCL-10, a critical chemokine for attraction of Tc1 cells. When i.p. JSI-124 administration was combined with i.v. transfer of Pmel-I mouse-derived type-1 CTLs (Tc1), glioma-bearing mice exhibited prolonged survival compared with i.p. JSI-124 or i.v. Tc1 therapy alone. Flow cytometric analyses of brain infiltrating lymphocytes revealed that JSI-124-treatment enhanced the tumor-homing of i.v. transferred Tc1 cells in a CXCL-10-dependent fashion. Systemic JSI-124 administration also up-regulated serum IL-15 levels, and promoted the persistence of transferred Tc1 in the host. These data suggest that systemic inhibition of STAT3 signaling can reverse the suppressive immunological environment of intracranial tumor bearing mice both systemically and locally, thereby promoting the efficacy of adoptive transfer therapy with Tc1.
Preassociation of IL-15 with IL-15Rα-IgG1-Fc Enhances Its Activity on Proliferation of NK and CD8+/CD44high T Cells and Its Antitumor Action
Authors: Dubois Sigrid , Patel Hiral J. , Zhang Meili , Waldmann Thomas A. , Müller Jürgen R. 
Published: April 2014

Abstract
In the induction of an immune response, IL-15Rα on APCs transpresents IL-15 to NK and CD8+/CD44high T cells that express the IL-2/15Rβ and γc subunits only. In this study, we show data mimicking this transpresentation by using IL-15 preassociated with a chimeric protein that is comprised of the extracellular domain of murine IL-15Rα and the Fc portion of human IgG1. When tested in vitro, IL-15Rα-IgG1-Fc strongly increased the IL-15-mediated proliferation of murine NK and CD8+/CD44high T cells. The effect of IL-15Rα-IgG1-Fc was dependent on the presence of both IgG1-Fc and IL-15Rα. When injected into mice, IL-15Rα-IgG1-Fc enhanced the capacity of IL-15 to expand the number of NK and CD8+/CD44high T cells. The effect on cell numbers in vivo also depended on Fc receptor binding because reduced expansion was observed in FcRγ−/− mice. NK cells cultured in IL-15/IL-15Rα-IgG1-Fc complex gained cytotoxic activity toward a number of NK-sensitive targets. When mice bearing the NK-sensitive syngeneic tumor B16 were treated, the presence of IL-15Rα-IgG1-Fc increased the antitumor activity of IL-15. Thus, a preassociation with IL-15Rα-IgG1-Fc enhances the activities of IL-15 in vivo and in vitro that may be useful in the treatment of tumors.
Prostaglandin E2 Suppresses Lipopolysaccharide-Stimulated IFN-β Production
Authors: Xu X. Julia , Reichner Jonathan S. , Mastrofrancesco Balduino , Henry William L. , Albina Jorge E. 
Published: April 2014

Abstract
Macrophages activate the production of cytokines and chemokines in response to LPS through signaling cascades downstream from TLR4. Lipid mediators such as PGE2, which are produced during inflammatory responses, have been shown to suppress MyD88-dependent gene expression upon TLR4 activation in macrophages. The study reported here investigated the effect of PGE2 on TLR3- and TLR4-dependent, MyD88-independent gene expression in murine J774A.1 macrophages, as well as the molecular mechanism underlying such an effect. We demonstrate that PGE2 strongly suppresses LPS-induced IFN-β production at the mRNA and protein levels. Poly (I:C)-induced IFN-β and LPS-induced CCL5 production were also suppressed by PGE2. The inhibitory effect of PGE2 on LPS-induced IFN-β expression is mediated through PGE2 receptor subtypes EP2 and EP4, and mimicked by the cAMP analog 8-Br-cAMP as well as by the adenylyl cyclase activator forskolin. The downstream effector molecule responsible for the cAMP-induced suppressive effect is exchange protein directly activated by cAMP (Epac) but not protein kinase A. Moreover, data demonstrate that Epac-mediated signaling proceeds through PI3K, Akt, and GSK3β. In contrast, PGE2 inhibits LPS-induced TNF-α production in these cells through a distinct pathway requiring protein kinase A activity and independent of Epac/PI3K/Akt. In vivo, administration of a cyclooxygenase inhibitor before LPS injection resulted in enhanced serum IFN-β concentration in mice. Collectively, data demonstrate that PGE2 is a negative regulator for IFN-β production in activated macrophages and during endotoxemia.