bluuebunny/crossref_metadata_2025_split huggingface dataset:
Down-Regulation of E-Cadherin in Human Bronchial Epithelial Cells Leads to Epidermal Growth Factor Receptor-Dependent Th2 Cell-Promoting Activity
Authors: Heijink Irene H. , Kies P. Marcel , Kauffman Henk F. , Postma Dirkje S. , van Oosterhout Antoon J. M. , Vellenga Edo 
Published: April 2014

Abstract
Airway epithelial cells are well-known producers of thymus- and activation-regulated chemokine (TARC), a Th2 cell-attracting chemokine that may play an important role in the development of allergic airway inflammation. However, the mechanism responsible for up-regulation of TARC in allergy is still unknown. In the asthmatic airways, loss of expression of the cell-cell contact molecule E-cadherin and reduced epithelial barrier function has been observed, which may be the result of an inadequate repair response. Because E-cadherin also suppressed multiple signaling pathways, we studied whether disruption of E-cadherin-mediated cell contact may contribute to increased proallergic activity of epithelial cells, e.g., production of the chemokine TARC. We down-regulated E-cadherin in bronchial epithelial cells by small interference RNA and studied effects on electrical resistance, signaling pathways, and TARC expression (by electric cell-substrate impedance sensing, immunodetection, immunofluorescent staining, and real-time PCR). Small interference RNA silencing of E-cadherin resulted in loss of E-cadherin-mediated junctions, enhanced phosphorylation of epidermal growth factor receptor (EGFR), and the downstream targets MEK/ERK-1/2 and p38 MAPK, finally resulting in up-regulation of TARC as well as thymic stromal lymphopoietin expression. The use of specific inhibitors revealed that the effect on TARC is mediated by EGFR-dependent activation of the MAPK pathways. In contrast to TARC, expression of the Th1/Treg cell-attracting chemokine RANTES was unaffected by E-cadherin down-regulation. In summary, we show that loss of E-cadherin-mediated epithelial cell-cell contact by damaging stimuli, e.g., allergens, may result in reduced suppression of EGFR-dependent signaling pathways and subsequent induction of Th2 cell-attracting molecule TARC. Thus, disruption of intercellular epithelial contacts may specifically promote Th2 cell recruitment in allergic asthma.
Phenotypic and Functional Effects of Heat Shock Protein 90 Inhibition on Dendritic Cell
Authors: Bae Jooeun , Mitsiades Constantine , Tai Yu-Tzu , Bertheau Robert , Shammas Masood , Batchu Ramesh Babu , Li Cheng , Catley Lawrence , Prabhala Rao , Anderson Kenneth C. , Munshi Nikhil C. 
Published: April 2014

Abstract
The 90-kDa heat shock protein (Hsp90) plays an important role in conformational regulation of cellular proteins and thereby cellular signaling and function. As Hsp90 is considered a key component of immune function and its inhibition has become an important target for cancer therapy, we here evaluated the role of Hsp90 in human dendritic cell (DC) phenotype and function. Hsp90 inhibition significantly decreased cell surface expression of costimulatory (CD40, CD80, CD86), maturation (CD83), and MHC (HLA-A, B, C and HLA-DP, DQ, DR) markers in immature DC and mature DC and was associated with down-regulation of both RNA and intracellular protein expression. Importantly, Hsp90 inhibition significantly inhibited DC function. It decreased Ag uptake, processing, and presentation by immature DC, leading to reduced T cell proliferation in response to tetanus toxoid as a recall Ag. It also decreased the ability of mature DC to present Ag to T cells and secrete IL-12 as well as induce IFN-γ secretion by allogeneic T cells. These data therefore demonstrate that Hsp90-mediated protein folding is required for DC function and, conversely, Hsp90 inhibition disrupts the DC function of significant relevance in the setting of clinical trials evaluating novel Hsp90 inhibitor therapy in cancer.
Transcriptional Targeting of B Cells for Induction of Peripheral CD8 T Cell Tolerance
Authors: Werner-Klein Melanie , Dresch Christiane , Marconi Peggy , Brocker Thomas 
Published: April 2014

Abstract
Several mechanisms are in place to neutralize autoimmune CD8 T cells by tolerance induction. Developing self-specific CD8 T cells are eliminated in the thymus by Ag-presenting epithelial and dendritic cells (DCs). However, CD8 T cells escaping thymic central tolerance can also be inactivated by tolerance mechanisms in peripheral organs. In contrast to DCs, the role of B cells in generating CD8 T cell tolerance is not well-characterized. To investigate this question in more detail, we transcriptionally targeted Ag to B cells using B cell-specific retroviral vectors in vivo. Although Ag expression could be detected in B cells of thymus, lymph nodes, and spleen, B cells were unable to induce central tolerance of CD8 thymocytes. In contrast, in peripheral organs, we could identify clonal deletion and functional inhibition (anergy) of CD8 T cells as tolerance-inducing mechanisms. Although Ag expressed by B cells was acquired and cross-presented by DCs, B cells were also sufficient to tolerize CD8 T cells directly. These findings suggest exploitation of B cells for Ag-specific immunotherapy of CD8 T cell-mediated autoimmune diseases.
TLR Agonists Selectively Promote Terminal Plasma Cell Differentiation of B Cell Subsets Specialized in Thymus-Independent Responses
Authors: Genestier Laurent , Taillardet Morgan , Mondiere Paul , Gheit Hanane , Bella Chantal , Defrance Thierry 
Published: April 2014

Abstract
Naive murine B cells are known to proliferate and differentiate in response to LPS or CpG, which bind to TLR4 and TLR9, respectively. However, the naive murine B cell compartment is heterogeneous and comprises four different B cell subsets: B-1a, B-1b, marginal zone (MZ), and follicular (FO) B cells. B-1a, B-1b, and MZ B cells are specialized in the response to thymus-independent Ag, and FO B cells are involved in the response to thymus-dependent Ag. This study was undertaken to compare those four naive B cell subsets for their responses to TLR agonists. Quantitative RT-PCR analysis revealed that expression of TLR transcripts differs quantitatively but not qualitatively from one subset to the other. All TLR agonists, with the exception of flagellin and poly(I:C), stimulate B cell proliferation whatever the subset considered. However, TLR ligation leads to massive differentiation of B-1 and MZ B cells into mature plasma cells (PC) but only marginally promotes PC differentiation of FO B cells. Moreover, TLR stimulation strongly up-regulates expression of Blimp-1 and XBP-1S, two transcription factors known to be instrumental in PC differentiation, in B-1 and MZ B cells but not in FO B cells. Altogether, our findings suggest that B-1 and MZ B cells are poised to PC differentiation in response to the microbial environment and that TLR agonists can be instrumental in stimulating Ab-mediated innate immune protection during microbial infections.
Protein Kinase Cδ Regulates Antigen Receptor-Induced Lytic Granule Polarization in Mouse CD8+ CTL
Authors: Ma Jennifer S. Y. , Monu Ngozi , Shen David T. , Mecklenbräuker Ingrid , Radoja Nadežda , Haydar Tarik F. , Leitges Michael , Frey Alan B. , Vukmanović Stanislav , Radoja Saša 
Published: April 2014

AbstractLytic granule exocytosis is the major pathway used by CD8+ CTL to kill virally infected and tumor cells. Despite the obvious importance of this pathway in adaptive T cell immunity, the molecular identity of enzymes involved in the regulation of this process is poorly characterized. One signal known to be critical for the regulation of granule exocytosis-mediated cytotoxicity in CD8+ T cells is Ag receptor-induced activation of protein kinase C (PKC). However, it is not known which step of the process is regulated by PKC. In addition, it has not been determined to date which of the PKC family members is required for the regulation of lytic granule exocytosis. By combination of pharmacological inhibitors and use of mice with targeted gene deletions, we show that PKCδ is required for granule exocytosis-mediated lytic function in mouse CD8+ T cells. Our studies demonstrate that PKCδ is required for lytic granule exocytosis, but is dispensable for activation, cytokine production, and expression of cytolytic molecules in response to TCR stimulation. Importantly, defective lytic function in PKCδ-deficient cytotoxic lymphocytes is reversed by ectopic expression of PKCδ. Finally, we show that PKCδ is not involved in target cell-induced reorientation of the microtubule-organizing center, but is required for the subsequent exocytosis step, i.e., lytic granule polarization. Thus, our studies identify PKCδ as a novel and selective regulator of Ag receptor-induced lytic granule polarization in mouse CD8+ T cells.
Follicular Dendritic Cell Secreted Protein (FDC-SP) Regulates Germinal Center and Antibody Responses
Authors: Al-Alwan Monther , Du Qiujiang , Hou Sen , Nashed Baher , Fan Yijun , Yang Xi , Marshall Aaron J. 
Published: April 2014

Abstract
We previously identified follicular dendritic cell secreted protein (FDC-SP), a small secreted protein of unknown function expressed in human tonsillar germinal centers (GC). To assess potential in vivo activities of FDC-SP, transgenic mice were generated to constitutively express FDC-SP in lymphoid tissues. FDC-SP transgenic mice show relatively normal development of immune cell populations, with the exception of a small increase in mature follicular B cells, and normal lymphoid tissue architecture. Upon immunization with a T-dependent Ag, FDC-SP transgenic mice were capable of producing an Ag-specific Ab; however, the titers of Ag-specific IgG2a and IgE were significantly reduced. GC responses after immunization were markedly diminished, with transgenic mice showing decreased numbers and sizes of GCs but normal development of follicular dendritic cell networks and normal positioning of GCs. FDC-SP transgenic mice also showed reduced production of Ag-specific IgG3 Ab after immunization with a type II T-independent Ag, suggesting that the FDC-SP can also regulate the induction of B cell responses outside the GC. Purified FDC-SP transgenic B cells function normally in vitro, with the exception of blunted chemotaxis responses to CXCL12 and CXCL13. FDC-SP can induce the chemotaxis of CD40-stimulated nontransgenic B cells and can significantly enhance B cell migration in combination with chemokines, indicating that FDC-SP may function in part by regulating B cell chemotaxis. These results provide the first evidence for immunomodulatory activities of FDC-SP and implicate this molecule as a regulator of B cell responses.
A Quantitative Analysis of the Variables Affecting the Repertoire of T Cell Specificities Recognized after Vaccinia Virus Infection
Authors: Assarsson Erika , Sidney John , Oseroff Carla , Pasquetto Valerie , Bui Huynh-Hoa , Frahm Nicole , Brander Christian , Peters Bjoern , Grey Howard , Sette Alessandro 
Published: April 2014

Abstract
Many components contribute to immunodominance in the response to a complex virus, but their relative importance is unclear. This was addressed using vaccinia virus and HLA-A*0201 as the model system. A comprehensive analysis of 18 viral proteins recognized by CD8+ T cell responses demonstrated that approximately one-fortieth of all possible 9- to 10-mer peptides were high-affinity HLA-A*0201 binders. Peptide immunization and T cell recognition data generated from 90 peptides indicated that about one-half of the binders were capable of eliciting T cell responses, and that one-seventh of immunogenic peptides are generated by natural processing. Based on these results, we estimate that vaccinia virus encodes ∼150 dominant and subdominant epitopes restricted in by HLA-A*0201. However, of all these potential epitopes, only 15 are immunodominant and actually recognized in vivo during vaccinia virus infection of HLA-A*0201 transgenic mice. Neither peptide-binding affinity, nor complex stability, nor TCR avidity, nor amount of processed epitope appeared to strictly correlate with immunodominance status. Additional experiments suggested that vaccinia infection impairs the development of responses directed against subdominant epitopes. This suggested that additional factors, including immunoregulatory mechanisms, restrict the repertoire of T cell specificities after vaccinia infection by a factor of at least 10.
RNA Interference Elucidates the Role of Focal Adhesion Kinase in HLA Class I-Mediated Focal Adhesion Complex Formation and Proliferation in Human Endothelial Cells
Authors: Jin Yi-Ping , Korin Yael , Zhang Xiaohai , Jindra Peter T. , Rozengurt Enrique , Reed Elaine F. 
Published: April 2014

Abstract
Ligation of class I molecules by anti-HLA Ab stimulates an intracellular signaling cascade resulting in endothelial cell (EC) survival and proliferation, and has been implicated in the process of chronic allograft rejection and transplant-associated vasculopathy. In this study, we used small interfering RNA blockade of focal adhesion kinase (FAK) protein to determine its role in class I-mediated organization of the actin cytoskeleton, cell survival, and cell proliferation in primary cultures of human aortic EC. Knockdown of FAK appreciably inhibited class I-mediated phosphorylation of Src at Tyr418, p85 PI3K, and Akt at both Thr308 and Ser473 sites. FAK knockdown also reduced class I-mediated phosphorylation of paxillin at Try118 and blocked class I-induced paxillin assembly into focal contacts. FAK small interfering RNA completely abrogated class I-mediated formation of actin stress fibers. Interestingly, FAK knockdown did not modify fibroblast growth factor receptor expression induced by class I ligation. However, FAK knockdown blocked HLA class I-stimulated cell cycle proliferation in the presence and absence of basic fibroblast growth factor. This study shows that FAK plays a critical role in class I-induced cell proliferation, cell survival, and focal adhesion assembly in EC and may promote the development of transplant-associated vasculopathy.
Episodes of Natural Selection Shaped the Interactions of IgA-Fc with FcαRI and Bacterial Decoy Proteins
Authors: Abi-Rached Laurent , Dorighi Kristel , Norman Paul J. , Yawata Makoto , Parham Peter 
Published: April 2014

Abstract
FcαRI, a receptor for IgA-Fc, recruits myeloid cells to attack IgA-coated pathogens. By competing with FcαRI for IgA, bacterial decoys, like SSL7 of Staphylococcus aureus, subvert this defense. We examined how pathogen selection has driven the diversification and coevolution of IgA and FcαRI. In higher primates, the IgA binding site of FcαRI diversified under positive selection, a strong episode occurring in hominoid ancestors about the time of the IgA gene duplication. The differential binding of SSL7 to IgA-Fc of different species correlates with substitution at seven positions in IgA-Fc, two of which were positively selected in higher primates. Two others, which reduce SSL7 binding, emerged during episodes of positive selection in the rabbit and rodent lineages. The FcαRI-IgA interaction evolves episodically under two types of positive selection: pressure from pathogen decoys selects for IgA escape variants which, in turn, selects for FcαRI variants to keep up with the novel IgA. When FcαRI cannot keep up, its function is lost and the gene becomes susceptible to elimination, as occurred in the mouse genome, either by chance or selection on one of the many linked, variable immune system genes. A cluster of positively selected residues presents a putative binding site for unknown IgA-binding factors.
IL-10 Regulates Movement of Intestinally Derived CD4+ T Cells to the Liver
Authors: Bliss Susan K. , Bliss Stuart P. , Beiting Daniel P. , Alcaraz Ana , Appleton Judith A. 
Published: April 2014

Abstract
Diseases that affect the intestine may have hepatic manifestations, but the mechanisms involved in establishing hepatic disease secondarily remain poorly understood. We previously reported that IL-10 knockout (KO) mice developed severe necrotizing hepatitis following oral infection with Trichinella spiralis. In this study, we used this model of intestinal inflammation to further examine the role of IL-10 in regulating hepatic injury. Hepatic damage was induced by migrating newborn larvae. By delivering the parasite directly into the portal vein, we demonstrated that an ongoing intestinal immune response was necessary for the development of hepatitis. Intestinally derived CD4+ cells increased in the livers of IL-10 KO mice, and Ab-mediated blockade of MAdCAM-1 inhibited the accumulation of CD4+α4β7+ cells in the liver. Moreover, adoptive transfer of intestinally primed CD4+ T cells from IL-10 KO mice caused hepatitis in infected immunodeficient animals. Conversely, transfer of wild-type donor cells reduced the severity of hepatic inflammation in IL-10 KO recipients, demonstrating regulatory activity. Our results revealed that IL-10 prevented migration of intestinal T cells to the liver and inhibited the development of hepatitis.
Dendritic Cells Derived from Murine Colonic Mucosa Have Unique Functional and Phenotypic Characteristics
Authors: Takenaka Shunsuke , Safroneeva Ekaterina , Xing Zhou , Gauldie Jack 
Published: April 2014

AbstractDendritic cells (DCs) residing in different tissues and exposed to different organisms are likely to have different reactivities to their surrounding environment. Many studies use in vitro generated DCs to examine functions of these cells, but such cells may not truly reflect the nature of DCs and their in situ activities in vivo. We have used magnetic label-based technique to isolate colonic DCs to conduct derailed characterization of these cells. Colonic DCs comprise mainly CD11b+ DCs with few CD8α+ DCs or plasmacytoid DCs. Functionally, isolated colonic DCs are able to endocytose and process proteins, undergo maturation, and stimulate T cells to proliferate. Importantly, expression of TLRs by colonic DCs is significantly lower than that of their spleen counterparts; however, they appear to be as, or more, responsive to stimulation by oligodeoxynucleotides containing CpG motif based on their cytokine production. We speculate that colonic DCs have unique reactivities differing from DCs residing in other lymphoid tissues and are adapted for the unique microenvironment of the colonic mucosa and that these cells react uniquely to their environment.
Long-Term Commitment to Inflammation-Seeking Homing in CD4+ Effector Cells
Authors: Jennrich Silke , Ratsch Boris A. , Hamann Alf , Syrbe Uta 
Published: April 2014

Abstract
Access of T effector cells to sites of inflammation is a prerequisite for an efficient action in immune defense and is mediated by different, partly tissue-specific sets of adhesion molecules. To what extent lymphocytes memorize the site of initial priming and develop organ-specific homing properties is still a matter of debate. Notably, data on the stability of homing receptor expression on T cells in vivo are largely lacking. We approached this question by the adoptive transfer of CD4+ T cells sorted for the expression of P-selectin ligands, which contribute to migration into inflamed sites in skin and other tissues. We observed long-term expression of P-selectin ligands on roughly one-third of effector cells. On those cells that had lost P-selectin ligands, re-expression upon Ag challenge was observed but only within pLNs, similar to the organ-selective induction upon the primary activation of naive T cells. The frequency of cells stably expressing P-selectin ligands was higher when cells were repeatedly stimulated under permissive conditions in the presence of IL-12, indicating a gradual fixation of this phenotype. In line with that finding, isolated P-selectin ligand positive memory T cells showed the highest frequency of long-term expressing cells. A tissue-specific environment was not required for the long-term maintenance of P-selectin ligand expression on the subfraction of effector cells. These data indicate that the expression of selectin ligands can become clonally imprinted under certain conditions, but also that a major fraction of the cells remains flexible and subject to environmental modulation upon restimulation.
CD8+ T Cells Are Required for Inflammation and Destruction in Cigarette Smoke-Induced Emphysema in Mice
Authors: Maeno Toshitaka , Houghton A. McGarry , Quintero Pablo A. , Grumelli Sandra , Owen Caroline A. , Shapiro Steven D. 
Published: April 2014

Abstract
Increased numbers of T lymphocytes are observed in the lungs of patients with chronic obstructive pulmonary disease, but their role in the disease process is not known. We investigated the role of CD8+ T cells in inflammatory cell recruitment and lung destruction in a cigarette smoke-induced murine model of emphysema. In contrast to wild-type C57BL/6J mice that displayed macrophage, lymphocyte, and neutrophil recruitment to the lung followed by emphysema in response to cigarette smoke, CD8+ T cell-deficient (CD8−/−) mice had a blunted inflammatory response and did not develop emphysema when exposed to long-term cigarette smoke. Further studies supported a pathogenetic pathway whereby the CD8+ T cell product, IFN-γ-inducible protein-10, induces production of macrophage elastase (matrix metalloproteinase 12) that degrades elastin, both causing lung destruction directly and generating elastin fragments that serve as monocyte chemokines augmenting macrophage-mediated lung destruction. These studies demonstrate a requirement for CD8+ T cells for the development of cigarette smoke-induced emphysema and they provide a unifying pathway whereby CD8+ T cells are a central regulator of the inflammatory network in chronic obstructive pulmonary disease.
Monocyte Chemoattractant Protein-1 Production by Intestinal Myofibroblasts in Response to Staphylococcal Enterotoxin A: Relevance to Staphylococcal Enterotoxigenic Disease
Authors: Pinchuk Irina V. , Beswick Ellen J. , Saada Jamal I. , Suarez Giovanni , Winston John , Mifflin Randy C. , Di Mari John F. , Powell Don W. , Reyes Victor E. 
Published: April 2014

Abstract
Food poisoning due to staphylococcal enterotoxins A and B (SEA and SEB) affects hundreds of thousands of people annually. SEA and SEB induce massive intestinal cytokine production, which is believed to be the key factor in staphylococcal enterotoxin enteropathy. MHC class II molecules are the major receptors for staphylococcal enterotoxins. We recently demonstrated that normal human subepithelial intestinal myofibroblasts (IMFs) express MHC class II molecules. We hypothesized that IMFs are among the first cells to respond to staphylococcal enterotoxins and contribute to the cytokine production associated with staphylococcal enterotoxin pathogenesis. We demonstrated here that primary cultured IMFs bind staphylococcal enterotoxins in a MHC class II-dependent fashion in vitro. We also demonstrated that staphylococcal enterotoxins can cross a CaCo-2 epithelial monolayer in coculture with IMFs and bind to the MHC class II on IMFs. IMFs responded to SEA, but not SEB, exposure with 3- to 20-fold increases in the production of proinflammatory chemokines (MCP-1, IL-8), cytokines (IL-6), and growth factors (GM-CSF and G-CSF). The SEA induction of the proinflammatory mediators by IMFs resulted from the efficient cross-linking of MHC class II molecules because cross-linking of class II MHC by biotinylated anti-HLA-DR Abs induced similar cytokine patterns. The studies presented here show that MCP-1 is central to the production of other cytokines elicited by SEA in IMFs because its neutralization with specific Abs prevented the expression of IL-6 and IL-8 by IMFs. Thus, MCP-1 may play a leading role in initiation of inflammatory injury associated with staphylococcal enterotoxigenic disease.