Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Hog confinement workers are at high risk to develop chronic bronchitis as a result of their exposure to organic dust. Chronic bronchitis is characterized by inflammatory changes of the airway epithelium. A key mediator in inflammation is Toll-like receptor 2 (TLR2). We investigated the role of TLR2 in pulmonary inflammation induced by hog confinement dust. Normal human bronchial epithelial cells (NHBE) were grown in culture and exposed to hog confinement dust extract. Hog confinement dust upregulated airway epithelial cell TLR2 mRNA in a concentration- and time-dependent manner using real-time PCR. There was a similar increase in TLR2 protein at 48 h as shown by Western blot. TLR2 was upregulated on the surface of airway epithelial cells as shown by flow cytometry. A similar upregulation of pulmonary TLR2 mRNA and protein was shown in a murine model of hog confinement dust exposure. Hog confinement dust is known to stimulate epithelial cells to produce IL-6. To determine whether TLR2 expression was being regulated by IL-6, the production of IL-6 was blocked using an IL-6-neutralizing antibody. This resulted in attenuation of the dust-induced upregulation of TLR2. To further demonstrate the importance of IL-6 in the regulation of TLR2, NHBE were directly stimulated with recombinant human IL-6. IL-6 alone was able to upregulate TLR2 in airway epithelial cells. Hog confinement dust upregulates TLR2 in the airway epithelium through an IL-6-dependent mechanism.
Am J Physiol Lung Cell Mol Physiol 2008 Jun
PMID:Toll-like receptor 2 is upregulated by hog confinement dust in an IL-6-dependent manner in the airway epithelium. 1835 83

Toll-like receptor (TLR) ligands, i.e. lipopolysaccharide (LPS), induce dendritic cell (DC) production of both inflammatory and anti-inflammatory cytokines including interleukin (IL)-12, tumor necrosis factor (TNF)-alpha, and IL-10. The balance of inflammatory versus anti-inflammatory cytokines appears to be crucial to control immune homeostasis. In the present study, we investigated TLR-mediated regulation of inflammatory versus anti-inflammatory cytokine production using murine bone marrow derived conventional DCs. Standard LPS (sLPS) that contains lipoprotein, a TLR2 ligand, induced vigorous production of both IL-10 and IL-12 p40 by DCs. Highly purified LPS (ultra-pure LPS, upLPS) also induced vigorous production of IL-12 p40, but markedly low IL-10 production. Thus, signal deficiency through TLR2 appeared to result in marked reduction in DC production of IL-10 but not IL-12 p40 upon stimulation with upLPS. To examine this possibility, DCs were stimulated with Pam3CSK4, a synthetic ligand of TLR2, in addition to stimulation with upLPS. It was shown that Pam3CSK4 alone failed to induce IL-10 production. However, Pam3CSK4 synergistically enhanced upLPS-induced DC production of IL-10 but neither IL-12 p40 nor TNF-alpha. Extracellular signal-regulated kinase (ERK)1/2, p38 mitogen-activated protein kinase (MAPK), and c-jun N-terminal kinase (JNK)1/2 in DCs were significantly activated by upLPS stimulation. The upLPS-induced activities of these MAPKs were considerably enhanced by additional stimulation with Pam3CSK4. Blocking either p38 MAPK or JNK1/2 pathway completely inhibited the synergistic enhancement of the IL-10 production by DCs upon upLPS and Pam3CSK4 stimulation. Thus, cooperated stimulation of these MAPKs via TLR4 and TLR2 appeared to induce selective synergy in anti-inflammatory cytokine production by murine conventional DCs.
Mol Immunol 2008 May
PMID:Selective synergy in anti-inflammatory cytokine production upon cooperated signaling via TLR4 and TLR2 in murine conventional dendritic cells. 1837 43

Toll-like receptors (TLRs) are critical for the recognition of inhaled pathogens that deposit on the airway epithelial surface. The epithelial response to pathogens includes signaling cascades that activate the EGF receptor (EGFR). We hypothesized that TLRs communicate with EGFR via epithelial signaling to produce certain innate immune responses. Airway epithelium expresses the highest levels of TLR2, TLR3, TLR5, and TLR6, and here we found that ligands for these TLRs increased IL-8 and VEGF production in normal human bronchial epithelial cells. These effects were prevented by treatment with a selective inhibitor of EGFR phosphorylation (AG-1478), a metalloprotease (MP) inhibitor, a reactive oxygen species (ROS) scavenger, and an NADPH oxidase inhibitor. In an airway epithelial cell line (NCI-H292), TNF-alpha-converting enzyme (TACE) small interfering RNA (siRNA) was used to confirm that TACE is the MP involved in TLR ligand-induced IL-8 and VEGF production. We show that transforming growth factor (TGF)-alpha is the EGFR ligand in this signaling cascade by using TGF-alpha neutralizing antibody and by showing that epithelial production of TGF-alpha occurs in response to TLR ligands. Dual oxidase 1 (Duox1) siRNA was used to confirm that Duox1 is the NADPH oxidase involved in TLR ligand-induced IL-8 and VEGF production. We conclude that multiple TLR ligands induce airway epithelial cell production of IL-8 and VEGF via a Duox1--> ROS--> TACE--> TGF-alpha--> EGFR phosphorylation pathway. These results show for the first time that multiple TLRs in airway epithelial cells produce innate immune responses by activating EGFR via an epithelial cell signaling cascade.
Am J Physiol Lung Cell Mol Physiol 2008 Jun
PMID:Multiple TLRs activate EGFR via a signaling cascade to produce innate immune responses in airway epithelium. 1837 43

Gene delivery applications to treat lung diseases are, in some instances, suboptimal due to deleterious host inflammatory reactions. Current DNA plasmids (pDNA) exert toxicity in part via unmethylated CpG motifs that stimulate Toll-like receptor (TLR)9-expressing leukocytes; however, the airway epithelial response has not been well defined. Bronchial epithelial cells (BEAS-2B) were exposed to pDNA complexes and inflammatory mediators were measured. As patients with inflammatory lung disease are susceptible to infectious exacerbations, we also evaluated the reciprocal inflammatory response to pDNA and bacterial components lipopolysaccharide (LPS) and lipoteichoic acid (LTA), recognized by TLR4 and TLR2, respectively. Cells primed with pDNA synergistically expressed IL-8 mRNA and protein in response to LPS and LTA (3- to 5-fold). A similar induction was also observed for IL-1beta, IL-6, colony-stimulating factor (CSF)-1, and granulocyte macrophage-CSF. Their synergistic elevation was associated with an increase in TLR4 and TLR2 levels. Methylation of pDNA only partially reduced (25-30%) IL-8 release; hence, signaling occurs via CpG/TLR9-dependent and -independent modules. As epidermal growth factor receptor (EGFR) signaling has been implicated in bronchial IL-8 expression, we assessed whether pDNA priming events were coordinated via EGFR. AG1478 (EGFR inhibitor) restored normal TLR4/2 levels and also suppressed synergistic release of IL-8. The extracellular signal-regulated kinase (Erk) mitogen-activated protein kinase inhibitor also blocked IL-8 release, implicating Erk as a key mediator of EGFR signaling. Our findings identify a novel EGFR-dependent mechanism for regulating TLR, and show that targeted disruption of EGFR signaling ameliorates the airway epithelial inflammatory response to pDNA. Targeting the EGFR system may improve the efficiency, tolerability, and safety of gene therapy strategies.
Am J Respir Cell Mol Biol 2008 Sep
PMID:DNA vector augments inflammation in epithelial cells via EGFR-dependent regulation of TLR4 and TLR2. 1840 79

Mycobacterium avium (MAV) and M. abscessus (MAB) are ubiquitous environmental organisms increasingly recognized to cause chronic lung disease in patients with apparently normal immune function. Little is yet known about their human pathophysiology. Our objective was to examine cytokine and chemokine responses (protein and gene expression) and signaling pathways triggered by reference and clinical isolates of MAB and MAV in human peripheral blood mononuclear cells, monocytes, and murine bone marrow-derived macrophages in vitro. MAB-induced TNF-alpha production was higher than that induced by MAV. IFN-gamma, IL-1beta, and the chemokines macrophage inflammatory protein-1alpha and regulated on activation, normal T cell expressed and secreted were equally up-regulated. Differences between MAB and MAV do not require replication and are heat stable. We found no differential effect due to rough or smooth colonies within the same species. Similar to MAV, MAB triggered mitogen-activated protein kinase (MAPK) signaling and nuclear factor-kappaB translocation. Induction of TNF-alpha was dependent on MAPK pathways, since pre-incubation of cells with signaling inhibitors led to more than 85% reduction in cytokine secretion. MAB also triggered a Toll-like receptor 2 (TLR2)-mediated response that led to TNF-alpha production by human monocytes. Accordingly, stimulation of murine TLR2- or myeloid differentiation factor 88-deficient bone marrow-derived macrophages did not elicit TNF-alpha, reinforcing a critical role for TLR2 in MAB-induced cell activation. We concluded that MAB signals human cells through MAPK and TLR2 pathways and triggers more pronounced pro-inflammatory cytokines and chemokines than MAV.
Am J Respir Cell Mol Biol 2008 Oct
PMID:Mycobacterium abscessus and M. avium trigger Toll-like receptor 2 and distinct cytokine response in human cells. 1844 Dec 80

The purpose of this study was to investigate the expression of IL-16 in the rheumatoid synovium and the role of inflammatory cytokines and Toll-like receptor (TLR) ligands in IL-16 production by fibroblast-like synoviocytes (FLS) of rheumatoid arthritis (RA) patients. Immunohistochemical staining was performed with a monoclonal antibody to IL-16 in synovial tissues from patients with RA and likewise in patients with osteoarthritis (OA). FLS were isolated from RA synovial tissues and stimulated with IL-15, IL-1beta, IFN-gamma, and IL-17. The IL-16 mRNA level was assessed by semiquantitative RT-PCR and real time (RT) PCR and a comparison was made between IL-16 mRNA levels produced by RA-FLS and OA-FLS. Production of IL-16 was identified by a western blot assay, and IL-16 production after stimulation by specific ligands of TLR2 and TLR4 was assessed by RT-PCR. While immunohistochemical staining demonstrated strong expression of IL-16 mRNA in synovial tissues from patients with RA, similar findings were not present in the OA group. Moreover, mRNA expression of IL-16 by RA-FLS increased after treatment with IL-17 but not with IL-15, IL-1beta, and IFN-gamma. Specifically, IL-17 increased IL-16 mRNA level by RA-FLS and peripheral blood mononuclear cells in a dose-dependent manner. However, IL-17 did not stimulate IL-16 production in OA-FLS. Peptidoglycan, a selective TLR2 ligand, also increased production of IL-16 by RA-FLS dose- dependently, whereas LPS, a selective TLR4 ligand, had no such stimulatory effect. The results from our data demonstrate that IL-17 and TLR2 ligands stimulate the production of IL-16 by RA-FLS.
Exp Mol Med 2008 Apr 30
PMID:IL-17 induces the production of IL-16 in rheumatoid arthritis. 1844 62

The generation of recombinant antibodies (Abs) using phage display is a proven method to obtain a large variety of Abs that bind with high affinity to a given antigen. Traditionally, the generation of single-chain Abs depends on the use of recombinant proteins in several stages of the procedure. This can be a problem, especially in the case of cell-surface receptors, because Abs generated and selected against recombinant proteins may not bind the same protein expressed on a cell surface in its native form and because the expression of some receptors as recombinant proteins is problematic. To overcome these difficulties, we developed a strategy to generate single-chain Abs that does not require the use of recombinant protein at any stage of the procedure. In this strategy, stably transfected cells are used for the immunization of mice, measuring Ab responses to immunization, panning the phage library, high-throughput screening of arrayed phage clones, and characterization of recombinant single-chain variable regions. This strategy was used to generate a panel of single-chain Abs specific for the innate immunity receptor Toll-like receptor 2. Once generated, individual single-chain variable regions were subcloned into an expression vector allowing the production of recombinant Abs in insect cells, thus avoiding the contamination of recombinant Abs with microbial products. This cell-based system efficiently generates Abs that bind to native molecules on the cell surface, bypasses the requirement of recombinant protein production, and avoids risks of microbial component contamination.
J Mol Biol 2008 May 30
PMID:An entirely cell-based system to generate single-chain antibodies against cell surface receptors. 1845 37

The spirochete Borrelia burgdorferi, the etiologic agent of Lyme disease, causes severe subacute arthritis in susceptible inbred mouse strains, such as C3H/HeN, but only mild arthritis in resistant strains such as C57BL/6. The degree of Lyme arthritis severity is controlled in part by host genetics and several quantitative trait loci have been identified which contribute to this regulation. In addition, the anti-inflammatory cytokine IL-10 assumes an important role in the control of arthritis in C57BL/6 mice. However, the identification of genes and signaling pathways that dictate arthritis severity has remained elusive. In an attempt to elucidate such genes and pathways, the power of microarray analysis was combined with information gleaned from gene manipulation models. As a result of this approach, two novel gene profiles were identified: an IFN-inducible profile in arthritis-susceptible C3H and IL-10(-/-) mice, and an epidermal/differentiation profile in C57BL/6 mice. Application of this information to TLR2(-/-) mice, which also develop severe arthritis, indicated that they also upregulated IFN-responsive genes. These results provided new insight into the regulation of Lyme arthritis development and illustrated the utility of combining gene expression analyses with genetically manipulated mouse models in unraveling mechanisms underlying specific disease processes.
Exp Mol Pathol 2008 Aug
PMID:Gene expression profiling provides insights into the pathways involved in inflammatory arthritis development: murine model of Lyme disease. 1846 18

Streptococcus pneumoniae is the leading pathogen of community-acquired pneumonia and is a main cause of infectious deaths. However, little is known about host-pathogen interaction in human lung tissue. We tested the hypothesis that human alveolar macrophages (AMs) and alveolar epithelial cells (AECs) are important for initiating the host response against S. pneumoniae, and we evaluated the role of Toll-like receptor (TLR) 2, TLR4, and p38 mitogen-activated protein kinase (MAPK) signaling in the inflammatory response after pneumococcal infection. We established a novel model of acute S. pneumoniae infection using vital human lung specimens. In situ hybridization analysis showed that S. pneumoniae DNA was detected in 80 to 90% of AMs and 15 to 30% of AECs after in vitro infection accompanied by increased expression of inflammatory cytokines. Enhanced phosphorylation of p38 MAPK and increased TLR2 and 4 mRNA expression were observed in infected lung tissue. Thirty to fifty percent of AMs and 10 to 20% of AECs showed evidence of apoptosis 24 hours after pneumococcal infection. After macrophage deactivation with Clodronate/liposomes, infected lung tissue exhibited a significantly decreased release of inflammatory mediators. Inhibition of p38 MAPK signaling markedly reduced inflammatory cytokine release from human lungs, whereas TLR2 blockade revealed only minor effects. AMs are central resident immune cells during S. pneumoniae infection and are the main source of early proinflammatory cytokine release. p38 MAPK holds a major role in pathogen-induced pulmonary cytokine release and is a potential molecular target to modulate overwhelming lung inflammation.
Am J Respir Cell Mol Biol 2008 Nov
PMID:Modulation of the inflammatory response to Streptococcus pneumoniae in a model of acute lung tissue infection. 1848 19

Toll-like receptor (TLR) family is crucial for microbial elimination and homeostasis, and has an important immunoregulatory role. In this study, we comparatively analyze innate immune response and tissular injury elicited in BALB/c and C57BL/6 (B6) mice during acute Trypanosoma cruzi infection. The liver was the most affected tissue with numerous cellular infiltrates, apoptotic cells and necrotic areas. The apoptotic rate, evaluated by Hoescht stain, was highest in liver of B6. Infection increased transaminase activities in both mouse strains, although they were highest in B6. BALB/c showed sixfold higher parasitemias than B6 but the latter presented higher mortality (80%) than BALB/c (40%). To gain insight into the molecular basis, we investigated the TLRs commitment in liver. We found that, TLR2 and TLR4 were up-regulated in BALB/c while they were down-regulated in B6. However, TLR9 showed a diminution in BALB/c and an increase in B6 at the end of infection. Moreover, an intensified pro-inflammatory cytokine profile was observed in B6 and F4/80+ and Gr1+ leukocytes were the predominant cells in liver from both mouse strains. Thus, altered TLR2, TLR4 and TLR9 signalling and exacerbate inflammatory cytokine profile could be responsible of the fatal hepatic damage observed in infected B6.
Mol Immunol 2008 Aug
PMID:TLR2, TLR4 and TLR9 are differentially modulated in liver lethally injured from BALB/c and C57BL/6 mice during Trypanosoma cruzi acute infection. 1856 85


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