Sample records for protein toll-like receptor

  1. Heat shock proteins and toll-like receptors.

    PubMed

    Asea, Alexzander

    2008-01-01

    Researchers have only just begun to elucidate the relationship between heat shock proteins (HSP) and Toll-like receptors (TLR). HSP were originally described as an intracellular molecular chaperone of naïve, aberrantly folded, or mutated proteins and primarily implicated as a cytoprotective protein when cells are exposed to stressful stimuli. However, recent studies have ascribed novel functions to the Hsp70 protein depending on its localization: Surface-bound Hsp70 specifically activate natural killer (NK) cells, while Hsp70 released into the extracellular milieu specifically bind to Toll-like receptors (TLR) 2 and 4 on antigen-presenting cells (APC) and exerts immunoregulatory effects, including upregulation of adhesion molecules, co-stimulatory molecule expression, and cytokine and chemokine release-a process known as the chaperokine activity of Hsp70. This chapter discusses the most recent advances in the understanding of heat shock protein (HSP) and TLR interactions in general and highlights recent findings that demonstrate Hsp70 is a ligand for TLR and its biological significance.

  2. Mincle suppresses Toll-like receptor 4 activation.

    PubMed

    Greco, Stephanie H; Mahmood, Syed Kashif; Vahle, Anne-Kristin; Ochi, Atsuo; Batel, Jennifer; Deutsch, Michael; Barilla, Rocky; Seifert, Lena; Pachter, H Leon; Daley, Donnele; Torres-Hernandez, Alejandro; Hundeyin, Mautin; Mani, Vishnu R; Miller, George

    2016-07-01

    Regulation of Toll-like receptor responses is critical for limiting tissue injury and autoimmunity in both sepsis and sterile inflammation. We found that Mincle, a C-type lectin receptor, regulates proinflammatory Toll-like receptor 4 signaling. Specifically, Mincle ligation diminishes Toll-like receptor 4-mediated inflammation, whereas Mincle deletion or knockdown results in marked hyperresponsiveness to lipopolysaccharide in vitro, as well as overwhelming lipopolysaccharide-mediated inflammation in vivo. Mechanistically, Mincle deletion does not up-regulate Toll-like receptor 4 expression or reduce interleukin 10 production after Toll-like receptor 4 ligation; however, Mincle deletion decreases production of the p38 mitogen-activated protein kinase-dependent inhibitory intermediate suppressor of cytokine signaling 1, A20, and ABIN3 and increases expression of the Toll-like receptor 4 coreceptor CD14. Blockade of CD14 mitigates the increased sensitivity of Mincle(-/-) leukocytes to Toll-like receptor 4 ligation. Collectively, we describe a major role for Mincle in suppressing Toll-like receptor 4 responses and implicate its importance in nonmycobacterial models of inflammation. © Society for Leukocyte Biology.

  3. Toll-like receptor 4 promotes proliferation and apoptosis resistance in human papillomavirus-related cervical cancer cells through the Toll-like receptor 4/nuclear factor-κB pathway.

    PubMed

    Jiang, Ninghong; Xie, Feng; Guo, Qisang; Li, Ming-Qing; Xiao, Jingjing; Sui, Long

    2017-06-01

    Toll-like receptor 4 is overexpressed in various tumors, including cervical carcinoma. However, the role of Toll-like receptor 4 in cervical cancer remains controversial, and the underlying mechanisms are largely elusive. Therefore, Toll-like receptor 4 in cervical cancer and related mechanisms were investigated in this study. Quantitative reverse transcription polymerase chain reaction and western blot analyses were used to detect messenger RNA and protein levels in HeLa, Caski, and C33A cells with different treatments. Proliferation was quantified using Cell Counting Kit-8. Cell cycle distribution and apoptosis were assessed by flow cytometry. Higher levels of Toll-like receptor 4 expression were found in human papillomavirus-positive cells compared to human papillomavirus-negative cells. Proliferation of HeLa and Caski cells was promoted in lipopolysaccharide-stimulated groups but suppressed in short hairpin RNA-transfected groups. Apoptosis rates were lower in lipopolysaccharide-stimulated groups relative to short hairpin RNA-transfected groups. In addition, G2-phase distribution was enhanced when Toll-like receptor 4 was downregulated. Moreover, the pNF-κBp65 level was positively correlated with the Toll-like receptor 4 level in HeLa and Caski cells, though when an nuclear factor-κB inhibitor was applied to lipopolysaccharide-stimulated groups, the patterns of proliferation and apoptosis were opposite to those of the lipopolysaccharide-stimulated groups without inhibitor treatment. In conclusion, these data suggest that Toll-like receptor 4 promotes proliferation and apoptosis resistance in human papillomavirus-related cervical cancer cells at least in part through the Toll-like receptor 4/nuclear factor-κB pathway, which may be correlated with the occurrence and development of cervical carcinoma.

  4. Innate Immune Regulation by Toll-Like Receptors in the Brain

    PubMed Central

    Mallard, Carina

    2012-01-01

    The innate immune system plays an important role in cerebral health and disease. In recent years the role of innate immune regulation by toll-like receptors in the brain has been highlighted. In this paper the expression of toll-like receptors and endogenous toll-like receptor ligands in the brain and their role in cerebral ischemia will be discussed. Further, the ability of systemic toll-like receptor ligands to induce cerebral inflammation will be reviewed. Finally, the capacity of toll-like receptors to both increase (sensitization) and decrease (preconditioning/tolerance) the vulnerability of the brain to damage will be disclosed. Studies investigating the role of toll-like receptors in the developing brain will be emphasized. PMID:23097717

  5. A novel Toll like receptor with two TIR domains (HcToll-2) is involved in regulation of antimicrobial peptide gene expression of Hyriopsis cumingii.

    PubMed

    Ren, Qian; Lan, Jiang-Feng; Zhong, Xue; Song, Xiao-Jun; Ma, Fei; Hui, Kai-Min; Wang, Wen; Yu, Xiao-Qiang; Wang, Jin-Xing

    2014-07-01

    Animal Toll-like receptors (TLRs) are involved in innate immunity. Toll proteins are generally transmembrane proteins. In this study, an atypical Toll-like receptor (HcToll-2) was identified from the triangle-shell pearl mussel Hyriopsis cumingii, which belongs to phylum Mollusca. Unlike the typical Toll like receptors with extracellular leucine-rich repeats (LRRs), transmembrane, and intracellular Toll/interleukin-1 receptor (TIR) domains, HcToll-2 has two homologous TIR domains located at the C-terminal (designated as HcTIR1 and HcTIR2) and lacks a transmembrane domain. Phylogenetic analysis showed that HcTIR1 was clustered with TIR of sea anemone Toll, and HcTIR2 was clustered with TIR of Drosophila Toll. HcToll-2 mRNA could be detected in the hepatopancreas and was upregulated after challenge with Escherichia coli and Staphylococcus aureus. Recombinant HcLRR protein with GST tag could bind to bacteria and also to LPS and PGN. Over-expression of both HcTIR1 and HcTIR2 induced drosomycin genes in Drosophila S2 cells. RNAi analysis showed that HcToll-2 was required for the expression of theromacin, which is a cysteine-rich antimicrobial peptide (AMP) gene. This research is the first report of an atypical Toll-like receptor HcToll-2 involved in antibacterial immunity through induction of AMP expression. Copyright © 2014 Elsevier Ltd. All rights reserved.

  6. Structural complementarity of Toll/interleukin-1 receptor domains in Toll-like receptors and the adaptors Mal and MyD88.

    PubMed

    Dunne, Aisling; Ejdeback, Mikael; Ludidi, Phumzile L; O'Neill, Luke A J; Gay, Nicholas J

    2003-10-17

    The Toll/interleukin 1 receptor (TIR) domain is a region found in the cytoplasmic tails of members of the Toll-like receptor/interleukin-1 receptor superfamily. The domain is essential for signaling and is also found in the adaptor proteins Mal (MyD88 adaptor-like) and MyD88, which function to couple activation of the receptor to downstream signaling components. Experimental structures of two Toll/interleukin 1 receptor domains reveal a alpha-beta-fold similar to that of the bacterial chemotaxis protein CheY, and other evidence suggests that the adaptors can make heterotypic interactions with both the receptors and themselves. Here we show that the purified TIR domains of Mal and MyD88 can form stable heterodimers and also that Mal homodimers and oligomers are dissociated in the presence of ATP. To identify structural features that may contribute to the formation of signaling complexes, we produced models of the TIR domains from human Toll-like receptor 4 (TLR4), Mal, and MyD88. We found that although the overall fold is conserved the electrostatic surface potentials are quite distinct. Docking studies of the models suggest that Mal and MyD88 bind to different regions in TLRs 2 and 4, a finding consistent with a cooperative role of the two adaptors in signaling. Mal and MyD88 are predicted to interact at a third non-overlapping site, suggesting that the receptor and adaptors may form heterotetrameric complexes. The theoretical model of the interactions is supported by experimental data from glutathione S-transferase pull-downs and co-immunoprecipitations. Neither theoretical nor experimental data suggest a direct role for the conserved proline in the BB-loop in the association of TLR4, Mal, and MyD88. Finally we show a sequence relationship between the Drosophila protein Tube and Mal that may indicate a functional equivalence of these two adaptors in the Drosophila and vertebrate Toll pathways.

  7. Regulation of dendritic cell function through toll-like receptors.

    PubMed

    Kaisho, Tsuneyasu; Akira, Shizuo

    2003-12-01

    Higher animals establish host defense by orchestrating innate and adaptive immunity. This is mediated by professional antigen presenting cells, i.e. dendritic cells (DCs). DCs can incorporate pathogens, produce a variety of cytokines, maturate, and present pathogen-derived peptides to T cells, thereby inducing T cell activation and differentiation. These responses are triggered by microbial recognition through type I transmembrane proteins, Toll-like receptors (TLRs) on DCs. TLRs consist of ten members and each TLR is involved in recognizing a variety of microorganism-derived molecular structures. TLR ligands include cell wall components, proteins, nucleic acids, and synthetic chemical compounds, all of which can activate DCs as immune adjuvants.

  8. Subverting Toll-Like Receptor Signaling by Bacterial Pathogens

    PubMed Central

    McGuire, Victoria A.; Arthur, J. Simon C.

    2015-01-01

    Pathogenic bacteria are detected by pattern-recognition receptors (PRRs) expressed on innate immune cells, which activate intracellular signal transduction pathways to elicit an immune response. Toll-like receptors are, perhaps, the most studied of the PRRs and can activate the mitogen-activated protein kinase (MAPK) and Nuclear Factor-κB (NF-κB) pathways. These pathways are critical for mounting an effective immune response. In order to evade detection and promote virulence, many pathogens subvert the host immune response by targeting components of these signal transduction pathways. This mini-review highlights the diverse mechanisms that bacterial pathogens have evolved to manipulate the innate immune response, with a particular focus on those that target MAPK and NF-κB signaling pathways. Understanding the elaborate strategies that pathogens employ to subvert the immune response not only highlights the importance of these proteins in mounting effective immune responses, but may also identify novel approaches for treatment or prevention of infection. PMID:26648936

  9. Promoters, toll like receptors and microRNAs: a strange association.

    PubMed

    Korla, Kalyani; Arrigo, Patrizio; Mitra, Chanchal K

    2013-06-01

    Toll-like receptors (TLRs) are proteins that play key role in the innate immune system. In the present study, -1000 base pairs upstream are taken from the transcription start site of the various TLR genes (10 known) in human. About 40 microRNAs have been identified that share 12-19 nucleotide sequence similarity with the promoter regions of 10 TLRs. It is proposed that the microRNA performs potential role in identification of promoter sequence and initiation of transcription.

  10. Tyrosine Phosphorylation in Toll-Like Receptor Signaling

    PubMed Central

    Chattopadhyay, Saurabh; Sen, Ganes C.

    2014-01-01

    There is a wealth of knowledge about how different Ser/Thr protein kinases participate in Toll-like receptor (TLR) signaling. In many cases, we know the identities of the Ser/Thr residues of various components of the TLR-signaling pathways that are phosphorylated, the functional consequences of the phosphorylation and the responsible protein kinases. In contrast, the analysis of Tyr-phosphorylation of TLRs and their signaling proteins is currently incomplete, because several existing analyses are not systematic or they do not rely on robust experimental data. Nevertheless, it is clear that many TLRs require, for signaling, ligand-dependent phosphorylation of specific Tyr residues in their cytoplasmic domains; the list includes TLR2, TLR3, TLR4, TLR5, TLR8 and TLR9. In this article, we discuss the current status of knowledge on the effect of Tyr-phosphorylation of TLRs and their signaling proteins on their biochemical and biological functions, the possible identities of the relevant protein tyrosine kinases (PTKs) and the nature of regulations of PTK-mediated activation of TLR signaling pathways. PMID:25022196

  11. Amyloid-beta mediates the receptor of advanced glycation end product-induced pro-inflammatory response via toll-like receptor 4 signaling pathway in retinal ganglion cell line RGC-5.

    PubMed

    Lee, Jong-Jer; Wang, Pei-Wen; Yang, I-Hui; Wu, Chia-Lin; Chuang, Jiin-Haur

    2015-07-01

    Patients with diabetes mellitus have an increased risk of developing Alzheimer's disease. Amyloid-β, a product of amyloid precursor protein, is associated with neuro-inflammation in patients with Alzheimer's diseases. The correlation between amyloid-beta and advanced glycation end products, which accumulate in tissue of diabetic patients, is not clear. The aims of this study were to determine the effect of advanced glycation end product on the expression of amyloid precursor protein/amyloid-beta and associated pro-inflammatory responses in retinal ganglion cell line RGC-5. Treatment with advanced glycation end product produced upregulation of amyloid precursor protein and increased secretion of amyloid-β(1-40). Additionally, amyloid-β(1-40) induced toll-like receptor 4-dependent phosphorylation of tyrosine in myeloid differentiation primary response gene (88). We found that N-[N-(3,5-Difluorophenacetyl)-l-alanyl]-S-phenylglycine t-butyl ester, a γ-secretase inhibitor, reduced the secretion of amyloid-β(1-40) and inhibited the advanced glycation end product-induced activation of myeloid differentiation primary response gene (88). Amyloid-β(1-40) induced the activation of NF-κB and the expression of TNFα mRNA. Knockdown of toll-like receptor 4 inhibited the amyloid-β(1-40)-induced phosphorylation of p65 in NF-κB. Additionally, the nuclear translocation of p65 and transcriptions of TNFα were inhibited by siRNA knockdown of receptor of advanced glycation end product or toll-like receptor 4. The advanced glycation end product-induced secretion of VEGF-A was also reduced by knockdown of toll-like receptor 4. Taken together, our data suggested that amyloid-β(1-40) mediates the interaction between receptor of advanced glycation end product and toll-like receptor 4. Inhibition of the toll-like receptor 4 is an effective method for suppressing the amyloid-β(1-40)-induced pro-inflammatory responses in RGC-5 cells. Copyright © 2015 Elsevier Ltd. All rights

  12. IMPDHII Protein Inhibits Toll-like Receptor 2-mediated Activation of NF-κB*

    PubMed Central

    Toubiana, Julie; Rossi, Anne-Lise; Grimaldi, David; Belaidouni, Nadia; Chafey, Philippe; Clary, Guilhem; Courtine, Emilie; Pene, Frederic; Mira, Jean-Paul; Claessens, Yann-Erick; Chiche, Jean-Daniel

    2011-01-01

    Toll-like receptor 2 (TLR2) plays an essential role in innate immunity by the recognition of a large variety of pathogen-associated molecular patterns. It induces its recruitment to lipid rafts induces the formation of a membranous activation cluster necessary to enhance, amplify, and control downstream signaling. However, the exact composition of the TLR2-mediated molecular complex is unknown. We performed a proteomic analysis in lipopeptide-stimulated THP1 and found IMPDHII protein rapidly recruited to lipid raft. Whereas IMPDHII is essential for lymphocyte proliferation, its biologic function within innate immune signal pathways has not been established yet. We report here that IMPDHII plays an important role in the negative regulation of TLR2 signaling by modulating PI3K activity. Indeed, IMPDHII increases the phosphatase activity of SHP1, which participates to the inactivation of PI3K. PMID:21460227

  13. Endotoxin, Toll-like Receptor-4, and Atherosclerotic Heart Disease

    PubMed Central

    Horseman, Michael A.; Surani, Salim; Bowman, John D.

    2017-01-01

    Background: Endotoxin is a lipopolysaccharide (LPS) constituent of the outer membrane of most gram negative bacteria. Ubiquitous in the environment, it has been implicated as a cause or con-tributing factor in several disparate disorders from sepsis to heatstroke and Type II diabetes mellitus. Starting at birth, the innate immune system develops cellular defense mechanisms against environmen-tal microbes that are in part modulated through a series of receptors known as toll-like receptors. Endo-toxin, often referred to as LPS, binds to toll-like receptor 4 (TLR4)/ myeloid differentiation protein 2 (MD2) complexes on various tissues including cells of the innate immune system, smooth muscle and endothelial cells of blood vessels including coronary arteries, and adipose tissue. Entry of LPS into the systemic circulation ultimately leads to intracellular transcription of several inflammatory mediators. The subsequent inflammation has been implicated in the development and progression atherosclerosis and subsequent coronary artery disease and heart failure. Objective: The potential roles of endotoxin and TLR4 are reviewed regarding their role in the pathogen-esis of atherosclerotic heart disease. Conclusion: Atherosclerosis is initiated by inflammation in arterial endothelial and subendothelial cells, and inflammatory processes are implicated in its progression to clinical heart disease. Endotoxin and TLR4 play a central role in the inflammatory process, and represent potential targets for therapeutic intervention. Therapy with HMG-CoA inhibitors may reduce the expression of TLR4 on monocytes. Other therapeutic interventions targeting TLR4 expression or function may prove beneficial in athero-sclerotic disease prevention and treatment.

  14. Structure-Based Rational Design of a Toll-like Receptor 4 (TLR4) Decoy Receptor with High Binding Affinity for a Target Protein

    PubMed Central

    Lee, Sang-Chul; Hong, Seungpyo; Park, Keunwan; Jeon, Young Ho; Kim, Dongsup; Cheong, Hae-Kap; Kim, Hak-Sung

    2012-01-01

    Repeat proteins are increasingly attracting much attention as alternative scaffolds to immunoglobulin antibodies due to their unique structural features. Nonetheless, engineering interaction interface and understanding molecular basis for affinity maturation of repeat proteins still remain a challenge. Here, we present a structure-based rational design of a repeat protein with high binding affinity for a target protein. As a model repeat protein, a Toll-like receptor4 (TLR4) decoy receptor composed of leucine-rich repeat (LRR) modules was used, and its interaction interface was rationally engineered to increase the binding affinity for myeloid differentiation protein 2 (MD2). Based on the complex crystal structure of the decoy receptor with MD2, we first designed single amino acid substitutions in the decoy receptor, and obtained three variants showing a binding affinity (KD) one-order of magnitude higher than the wild-type decoy receptor. The interacting modes and contributions of individual residues were elucidated by analyzing the crystal structures of the single variants. To further increase the binding affinity, single positive mutations were combined, and two double mutants were shown to have about 3000- and 565-fold higher binding affinities than the wild-type decoy receptor. Molecular dynamics simulations and energetic analysis indicate that an additive effect by two mutations occurring at nearby modules was the major contributor to the remarkable increase in the binding affinities. PMID:22363519

  15. Toll-like receptor signaling in vertebrates: testing the integration of protein, complex, and pathway data in the protein ontology framework.

    PubMed

    Arighi, Cecilia; Shamovsky, Veronica; Masci, Anna Maria; Ruttenberg, Alan; Smith, Barry; Natale, Darren A; Wu, Cathy; D'Eustachio, Peter

    2015-01-01

    The Protein Ontology (PRO) provides terms for and supports annotation of species-specific protein complexes in an ontology framework that relates them both to their components and to species-independent families of complexes. Comprehensive curation of experimentally known forms and annotations thereof is expected to expose discrepancies, differences, and gaps in our knowledge. We have annotated the early events of innate immune signaling mediated by Toll-Like Receptor 3 and 4 complexes in human, mouse, and chicken. The resulting ontology and annotation data set has allowed us to identify species-specific gaps in experimental data and possible functional differences between species, and to employ inferred structural and functional relationships to suggest plausible resolutions of these discrepancies and gaps.

  16. Toll-like receptor activation in the pathogenesis of lupus nephritis.

    PubMed

    Lorenz, Georg; Lech, Maciej; Anders, Hans-Joachim

    2017-12-01

    The pathogenesis of systemic lupus erythematosus (SLE) and lupus nephritis is complex but no longer enigmatic. Much progress has been made to on the polygenetic origin of lupus in identifying gene variants that permit the loss of tolerance against nuclear autoantigens. Along the same line in about 50% of lupus patients additional genetic weaknesses promote immune complex glomerulonephritis and filtration barrier dysfunction. Here we briefly summarize the pathogenesis of SLE with a focus on loss of tolerance and the role of toll-like receptors in the "pseudo"-antiviral immunity concept of systemic lupus. In addition, we discuss the local role of Toll-like receptors in intrarenal inflammation and kidney remodeling. Copyright © 2016 Elsevier Inc. All rights reserved.

  17. Effects of Air Pollutants on Innate Immunity: The Role of Toll-like receptors and nucleotide-binding oligomerization domain-like receptors

    EPA Science Inventory

    Interactions between exposure to ambient air pollutants and respiratory pathogens have been shown to modify respiratory immune responses. Emerging data suggest key roles for toll-like receptor (TLR) and NOD-like receptor (NLR) signaling in pathogen-induced immune responses. Simil...

  18. Role of Adaptor Protein Toll-Like Interleukin Domain Containing Adaptor Inducing Interferon β in Toll-Like Receptor 3- and 4-Mediated Regulation of Hepatic Drug Metabolizing Enzyme and Transporter Genes.

    PubMed

    Shah, Pranav; Omoluabi, Ozozoma; Moorthy, Bhagavatula; Ghose, Romi

    2016-01-01

    The expressions and activities of hepatic drug-metabolizing enzymes and transporters (DMETs) are altered during infection and inflammation. Inflammatory responses in the liver are mediated primarily by Toll-like receptor (TLR)-signaling, which involves recruitment of Toll/interleukin (IL)-1 receptor (TIR) domain containing adaptor protein (TIRAP) and TIR domain containing adaptor inducing interferon (IFN)-β (TRIF) that eventually leads to induction of proinflammatory cytokines and mitogen-activated protein kinases (MAPKs). Lipopolysaccharide (LPS) activates the Gram-negative bacterial receptor TLR4 and polyinosinic:polycytidylic acid (polyI:C) activates the viral receptor TLR3. TLR4 signaling involves TIRAP and TRIF, whereas TRIF is the only adaptor protein involved in the TLR3 pathway. We have shown previously that LPS-mediated downregulation of DMETs is independent of TIRAP. To determine the role of TRIF, we treated TRIF(+/+) and TRIF(-/-) mice with LPS or polyI:C. LPS downregulated (∼40%-60%) Cyp3a11, Cyp2a4, Ugt1a1, Mrp2 mRNA levels, whereas polyI:C downregulated (∼30%-60%) Cyp3a11, Cyp2a4, Cyp1a2, Cyp2b10, Ugt1a1, Mrp2, and Mrp3 mRNA levels in TRIF(+/+) mice. This downregulation was not attenuated in TRIF(-/-) mice. Induction of cytokines by LPS was observed in both TRIF(+/+) and TRIF(-/-) mice. Cytokine induction was delayed in polyI:C-treated TRIF(-/-) mice, indicating that multiple mechanisms mediating polyI:C signaling exist. To assess the role of MAPKs, primary hepatocytes were pretreated with specific inhibitors before treatment with LPS/polyI:C. We found that only the c-jun-N-terminal kinase (JNK) inhibitor attenuated the down-regulation of DMETs. These results show that TRIF-independent pathways can be involved in the downregulation of DMETs through TLR4 and 3. JNK-dependent mechanisms likely mediate this downregulation. Copyright © 2015 by The American Society for Pharmacology and Experimental Therapeutics.

  19. Toll-Like Receptors in the Pathogenesis of Autoimmune Diseases

    PubMed Central

    Mohammad Hosseini, Akbar; Majidi, Jafar; Baradaran, Behzad; Yousefi, Mehdi

    2015-01-01

    Human Toll-like receptors (TLRs) are a family of transmembrane receptors, which play a key role in both innate and adaptive immune responses. Beside of recognizing specific molecular patterns that associated with different types of pathogens, TLRs may also detect a number of self-proteins and endogenous nucleic acids. Activating TLRs lead to the heightened expression of various inflammatory genes, which have a protective role against infection. Data rising predominantly from human patients and animal models of autoimmune disease indicate that, inappropriate triggering of TLR pathways by exogenous or endogenous ligands may cause the initiation and/or perpetuation of autoimmune reactions and tissue damage. Given their important role in infectious and non-infectious disease process, TLRs and its signaling pathways emerge as appealing targets for therapeutics. In this review, we demonstrate how TLRs pathways could be involved in autoimmune disorders and their therapeutic application. PMID:26793605

  20. Induction of Direct Antimicrobial Activity Through Mammalian Toll-Like Receptors

    NASA Astrophysics Data System (ADS)

    Thoma-Uszynski, Sybille; Stenger, Steffen; Takeuchi, Osamu; Ochoa, Maria Teresa; Engele, Matthias; Sieling, Peter A.; Barnes, Peter F.; Röllinghoff, Martin; Bölcskei, Pal L.; Wagner, Manfred; Akira, Shizuo; Norgard, Michael V.; Belisle, John T.; Godowski, Paul J.; Bloom, Barry R.; Modlin, Robert L.

    2001-02-01

    The mammalian innate immune system retains from Drosophila a family of homologous Toll-like receptors (TLRs) that mediate responses to microbial ligands. Here, we show that TLR2 activation leads to killing of intracellular Mycobacterium tuberculosis in both mouse and human macrophages, through distinct mechanisms. In mouse macrophages, bacterial lipoprotein activation of TLR2 leads to a nitric oxide-dependent killing of intracellular tubercle bacilli, but in human monocytes and alveolar macrophages, this pathway was nitric oxide-independent. Thus, mammalian TLRs respond (as Drosophila Toll receptors do) to microbial ligands and also have the ability to activate antimicrobial effector pathways at the site of infection.

  1. Toll-like receptor-associated keratitis and strategies for its management.

    PubMed

    Kaur, Amandeep; Kumar, Vijay; Singh, Simranjeet; Singh, Joginder; Upadhyay, Niraj; Datta, Shivika; Singla, Sourav; Kumar, Virender

    2015-10-01

    Keratitis is an inflammatory condition, characterized by involvement of corneal tissues. Most recurrent challenge of keratitis is infection. Bacteria, virus, fungus and parasitic organism have potential to cause infection. TLR are an important class of protein which has a major role in innate immune response to combat with pathogens. In last past years, extensive research efforts have provided considerable abundance information regarding the role of TLR in various types of keratitis. This paper focuses to review the recent literature illustrating amoebic, bacterial, fungal and viral keratitis associated with Toll-like receptor molecules and summarize existing thoughts on pathogenesis and treatment besides future probabilities for prevention against TLR-associated keratitis.

  2. An anti-interferon activity shared by paramyxovirus C proteins: inhibition of Toll-like receptor 7/9-dependent alpha interferon induction.

    PubMed

    Yamaguchi, Mayu; Kitagawa, Yoshinori; Zhou, Min; Itoh, Masae; Gotoh, Bin

    2014-01-03

    Paramyxovirus C protein targets the host interferon (IFN) system for virus immune evasion. To identify its unknown anti-IFN activity, we examined the effect of Sendai virus C protein on activation of the IFN-α promoter via various signaling pathways. This study uncovers a novel ability of C protein to block Toll-like receptor (TLR) 7- and TLR9-dependent IFN-α induction, which is specific to plasmacytoid dendritic cells. C protein interacts with a serine/threonine kinase IKKα and inhibits phosphorylation of IRF7. This anti-IFN activity of C protein is shared across genera of the Paramyxovirinae, and thus appears to play an important role in paramyxovirus immune evasion. Copyright © 2013 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

  3. Bacterial Stimulation of Toll-Like Receptor 4 Drives Macrophages To Hemophagocytose

    PubMed Central

    McDonald, Erin M.; Pilonieta, M. Carolina; Nick, Heidi J.

    2015-01-01

    During acute infection with bacteria, viruses or parasites, a fraction of macrophages engulf large numbers of red and white blood cells, a process called hemophagocytosis. Hemophagocytes persist into the chronic stage of infection and have an anti-inflammatory phenotype. Salmonella enterica serovar Typhimurium infection of immunocompetent mice results in acute followed by chronic infection, with the accumulation of hemophagocytes. The mechanism(s) that triggers a macrophage to become hemophagocytic is unknown, but it has been reported that the proinflammatory cytokine gamma interferon (IFN-γ) is responsible. We show that primary macrophages become hemophagocytic in the absence or presence of IFN-γ upon infection with Gram-negative bacterial pathogens or prolonged exposure to heat-killed Salmonella enterica, the Gram-positive bacterium Bacillus subtilis, or Mycobacterium marinum. Moreover, conserved microbe-associated molecular patterns are sufficient to stimulate macrophages to hemophagocytose. Purified bacterial lipopolysaccharide (LPS) induced hemophagocytosis in resting and IFN-γ-pretreated macrophages, whereas lipoteichoic acid and synthetic unmethylated deoxycytidine-deoxyguanosine dinucleotides, which mimic bacterial DNA, induced hemophagocytosis only in IFN-γ-pretreated macrophages. Chemical inhibition or genetic deletion of Toll-like receptor 4, a pattern recognition receptor responsive to LPS, prevented both Salmonella- and LPS-stimulated hemophagocytosis. Inhibition of NF-κB also prevented hemophagocytosis. These results indicate that recognition of microbial products by Toll-like receptors stimulates hemophagocytosis, a novel outcome of prolonged Toll-like receptor signaling, suggesting hemophagocytosis is a highly conserved innate immune response. PMID:26459510

  4. Toll-Like Receptor Pathways in Autoimmune Diseases.

    PubMed

    Chen, Ji-Qing; Szodoray, Peter; Zeher, Margit

    2016-02-01

    Autoimmune diseases are a family of chronic systemic inflammatory disorders, characterized by the dysregulation of the immune system which finally results in the break of tolerance to self-antigen. Several studies suggest that Toll-like receptors (TLRs) play an essential role in the pathogenesis of autoimmune diseases. TLRs belong to the family of pattern recognition receptors (PRRs) that recognize a wide range of pathogen-associated molecular patterns (PAMPs). TLRs are type I transmembrane proteins and located on various cellular membranes. Two main groups have been classified based on their location; the extracelluar group referred to the ones located on the plasma membrane while the intracellular group all located in endosomal compartments responsible for the recognition of nucleic acids. They are released by the host cells and trigger various intracellular pathways which results in the production of proinflammatory cytokines, chemokines, as well as the expression of co-stimulatory molecules to protect against invading microorganisms. In particular, TLR pathway-associated proteins, such as IRAK, TRAF, and SOCS, are often dysregulated in this group of diseases. TLR-associated gene expression profile analysis together with single nucleotide polymorphism (SNP) assessment could be important to explain the pathomechanism driving autoimmune diseases. In this review, we summarize recent findings on TLR pathway regulation in various autoimmune diseases, including Sjögren's syndrome (SS), systemic lupus erythematosus (SLE), multiple sclerosis (MS), rheumatoid arthritis (RA), systemic sclerosis (SSc), and psoriasis.

  5. Toll-like receptor ligands sensitize B-cell receptor signalling by reducing actin-dependent spatial confinement of the receptor.

    PubMed

    Freeman, Spencer A; Jaumouillé, Valentin; Choi, Kate; Hsu, Brian E; Wong, Harikesh S; Abraham, Libin; Graves, Marcia L; Coombs, Daniel; Roskelley, Calvin D; Das, Raibatak; Grinstein, Sergio; Gold, Michael R

    2015-02-03

    Integrating signals from multiple receptors allows cells to interpret the physiological context in which a signal is received. Here we describe a mechanism for receptor crosstalk in which receptor-induced increases in actin dynamics lower the threshold for signalling by another receptor. We show that the Toll-like receptor ligands lipopolysaccharide and CpG DNA, which are conserved microbial molecules, enhance signalling by the B-cell antigen receptor (BCR) by activating the actin-severing protein cofilin. Single-particle tracking reveals that increased severing of actin filaments reduces the spatial confinement of the BCR within the plasma membrane and increases BCR mobility. This allows more frequent collisions between BCRs and greater signalling in response to low densities of membrane-bound antigen. These findings implicate actin dynamics as a means of tuning receptor signalling and as a mechanism by which B cells distinguish inert antigens from those that are accompanied by indicators of microbial infection.

  6. Toll-like receptor ligands sensitize B-cell receptor signalling by reducing actin-dependent spatial confinement of the receptor

    PubMed Central

    Freeman, Spencer A.; Jaumouillé, Valentin; Choi, Kate; Hsu, Brian E.; Wong, Harikesh S.; Abraham, Libin; Graves, Marcia L.; Coombs, Daniel; Roskelley, Calvin D.; Das, Raibatak; Grinstein, Sergio; Gold, Michael R.

    2015-01-01

    Integrating signals from multiple receptors allows cells to interpret the physiological context in which a signal is received. Here we describe a mechanism for receptor crosstalk in which receptor-induced increases in actin dynamics lower the threshold for signalling by another receptor. We show that the Toll-like receptor ligands lipopolysaccharide and CpG DNA, which are conserved microbial molecules, enhance signalling by the B-cell antigen receptor (BCR) by activating the actin-severing protein cofilin. Single-particle tracking reveals that increased severing of actin filaments reduces the spatial confinement of the BCR within the plasma membrane and increases BCR mobility. This allows more frequent collisions between BCRs and greater signalling in response to low densities of membrane-bound antigen. These findings implicate actin dynamics as a means of tuning receptor signalling and as a mechanism by which B cells distinguish inert antigens from those that are accompanied by indicators of microbial infection. PMID:25644899

  7. Toll-like receptors and chronic inflammation in rheumatic diseases: new developments.

    PubMed

    Joosten, Leo A B; Abdollahi-Roodsaz, Shahla; Dinarello, Charles A; O'Neill, Luke; Netea, Mihai G

    2016-06-01

    In the past few years, new developments have been reported on the role of Toll-like receptors (TLRs) in chronic inflammation in rheumatic diseases. The inhibitory function of TLR10 has been demonstrated. Receptors that enhance the function of TLRs, and several TLR inhibitors, have been identified. In addition, the role of the microbiome and TLRs in the onset of rheumatic diseases has been reported. We review novel insights on the role of TLRs in several inflammatory joint diseases, including rheumatoid arthritis, systemic lupus erythematosus, gout and Lyme arthritis, with a focus on the signalling mechanisms mediated by the Toll-IL-1 receptor (TIR) domain, the exogenous and endogenous ligands of TLRs, and the current and future therapeutic strategies to target TLR signalling in rheumatic diseases.

  8. Rapidly Evolving Toll-3/4 Genes Encode Male-Specific Toll-Like Receptors in Drosophila.

    PubMed

    Levin, Tera C; Malik, Harmit S

    2017-09-01

    Animal Toll-like receptors (TLRs) have evolved through a pattern of duplication and divergence. Whereas mammalian TLRs directly recognize microbial ligands, Drosophila Tolls bind endogenous ligands downstream of both developmental and immune signaling cascades. Here, we find that most Toll genes in Drosophila evolve slowly with little gene turnover (gains/losses), consistent with their important roles in development and indirect roles in microbial recognition. In contrast, we find that the Toll-3/4 genes have experienced an unusually rapid rate of gene gains and losses, resulting in lineage-specific Toll-3/4s and vastly different gene repertoires among Drosophila species, from zero copies (e.g., D. mojavensis) to nineteen copies (e.g., D. willistoni). In D. willistoni, we find strong evidence for positive selection in Toll-3/4 genes, localized specifically to an extracellular region predicted to overlap with the binding site of Spätzle, the only known ligand of insect Tolls. However, because Spätzle genes are not experiencing similar selective pressures, we hypothesize that Toll-3/4s may be rapidly evolving because they bind to a different ligand, akin to TLRs outside of insects. We further find that most Drosophila Toll-3/4 genes are either weakly expressed or expressed exclusively in males, specifically in the germline. Unlike other Toll genes in D. melanogaster, Toll-3, and Toll-4 have apparently escaped from essential developmental roles, as knockdowns have no substantial effects on viability or male fertility. Based on these findings, we propose that the Toll-3/4 genes represent an exceptionally rapidly evolving lineage of Drosophila Toll genes, which play an unusual, as-yet-undiscovered role in the male germline. © The Author 2017. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

  9. Rapidly Evolving Toll-3/4 Genes Encode Male-Specific Toll-Like Receptors in Drosophila

    PubMed Central

    Levin, Tera C.; Malik, Harmit S.

    2017-01-01

    Abstract Animal Toll-like receptors (TLRs) have evolved through a pattern of duplication and divergence. Whereas mammalian TLRs directly recognize microbial ligands, Drosophila Tolls bind endogenous ligands downstream of both developmental and immune signaling cascades. Here, we find that most Toll genes in Drosophila evolve slowly with little gene turnover (gains/losses), consistent with their important roles in development and indirect roles in microbial recognition. In contrast, we find that the Toll-3/4 genes have experienced an unusually rapid rate of gene gains and losses, resulting in lineage-specific Toll-3/4s and vastly different gene repertoires among Drosophila species, from zero copies (e.g., D. mojavensis) to nineteen copies (e.g., D. willistoni). In D. willistoni, we find strong evidence for positive selection in Toll-3/4 genes, localized specifically to an extracellular region predicted to overlap with the binding site of Spätzle, the only known ligand of insect Tolls. However, because Spätzle genes are not experiencing similar selective pressures, we hypothesize that Toll-3/4s may be rapidly evolving because they bind to a different ligand, akin to TLRs outside of insects. We further find that most Drosophila Toll-3/4 genes are either weakly expressed or expressed exclusively in males, specifically in the germline. Unlike other Toll genes in D. melanogaster, Toll-3, and Toll-4 have apparently escaped from essential developmental roles, as knockdowns have no substantial effects on viability or male fertility. Based on these findings, we propose that the Toll-3/4 genes represent an exceptionally rapidly evolving lineage of Drosophila Toll genes, which play an unusual, as-yet-undiscovered role in the male germline. PMID:28541576

  10. Proteomic Analysis of ABCA1-Null Macrophages Reveals a Role for Stomatin-Like Protein-2 in Raft Composition and Toll-Like Receptor Signaling.

    PubMed

    Chowdhury, Saiful M; Zhu, Xuewei; Aloor, Jim J; Azzam, Kathleen M; Gabor, Kristin A; Ge, William; Addo, Kezia A; Tomer, Kenneth B; Parks, John S; Fessler, Michael B

    2015-07-01

    Lipid raft membrane microdomains organize signaling by many prototypical receptors, including the Toll-like receptors (TLRs) of the innate immune system. Raft-localization of proteins is widely thought to be regulated by raft cholesterol levels, but this is largely on the basis of studies that have manipulated cell cholesterol using crude and poorly specific chemical tools, such as β-cyclodextrins. To date, there has been no proteome-scale investigation of whether endogenous regulators of intracellular cholesterol trafficking, such as the ATP binding cassette (ABC)A1 lipid efflux transporter, regulate targeting of proteins to rafts. Abca1(-/-) macrophages have cholesterol-laden rafts that have been reported to contain increased levels of select proteins, including TLR4, the lipopolysaccharide receptor. Here, using quantitative proteomic profiling, we identified 383 proteins in raft isolates from Abca1(+/+) and Abca1(-/-) macrophages. ABCA1 deletion induced wide-ranging changes to the raft proteome. Remarkably, many of these changes were similar to those seen in Abca1(+/+) macrophages after lipopolysaccharide exposure. Stomatin-like protein (SLP)-2, a member of the stomatin-prohibitin-flotillin-HflK/C family of membrane scaffolding proteins, was robustly and specifically increased in Abca1(-/-) rafts. Pursuing SLP-2 function, we found that rafts of SLP-2-silenced macrophages had markedly abnormal composition. SLP-2 silencing did not compromise ABCA1-dependent cholesterol efflux but reduced macrophage responsiveness to multiple TLR ligands. This was associated with reduced raft levels of the TLR co-receptor, CD14, and defective lipopolysaccharide-induced recruitment of the common TLR adaptor, MyD88, to rafts. Taken together, we show that the lipid transporter ABCA1 regulates the protein repertoire of rafts and identify SLP-2 as an ABCA1-dependent regulator of raft composition and of the innate immune response. © 2015 by The American Society for Biochemistry and

  11. Proteomic Analysis of ABCA1-Null Macrophages Reveals a Role for Stomatin-Like Protein-2 in Raft Composition and Toll-Like Receptor Signaling*

    PubMed Central

    Chowdhury, Saiful M.; Zhu, Xuewei; Aloor, Jim J.; Azzam, Kathleen M.; Gabor, Kristin A.; Ge, William; Addo, Kezia A.; Tomer, Kenneth B.; Parks, John S.; Fessler, Michael B.

    2015-01-01

    Lipid raft membrane microdomains organize signaling by many prototypical receptors, including the Toll-like receptors (TLRs) of the innate immune system. Raft-localization of proteins is widely thought to be regulated by raft cholesterol levels, but this is largely on the basis of studies that have manipulated cell cholesterol using crude and poorly specific chemical tools, such as β-cyclodextrins. To date, there has been no proteome-scale investigation of whether endogenous regulators of intracellular cholesterol trafficking, such as the ATP binding cassette (ABC)A1 lipid efflux transporter, regulate targeting of proteins to rafts. Abca1−/− macrophages have cholesterol-laden rafts that have been reported to contain increased levels of select proteins, including TLR4, the lipopolysaccharide receptor. Here, using quantitative proteomic profiling, we identified 383 proteins in raft isolates from Abca1+/+ and Abca1−/− macrophages. ABCA1 deletion induced wide-ranging changes to the raft proteome. Remarkably, many of these changes were similar to those seen in Abca1+/+ macrophages after lipopolysaccharide exposure. Stomatin-like protein (SLP)-2, a member of the stomatin-prohibitin-flotillin-HflK/C family of membrane scaffolding proteins, was robustly and specifically increased in Abca1−/− rafts. Pursuing SLP-2 function, we found that rafts of SLP-2-silenced macrophages had markedly abnormal composition. SLP-2 silencing did not compromise ABCA1-dependent cholesterol efflux but reduced macrophage responsiveness to multiple TLR ligands. This was associated with reduced raft levels of the TLR co-receptor, CD14, and defective lipopolysaccharide-induced recruitment of the common TLR adaptor, MyD88, to rafts. Taken together, we show that the lipid transporter ABCA1 regulates the protein repertoire of rafts and identify SLP-2 as an ABCA1-dependent regulator of raft composition and of the innate immune response. PMID:25910759

  12. Investigating the effect of key mutations on the conformational dynamics of toll-like receptor dimers through molecular dynamics simulations and protein structure networks.

    PubMed

    Mahita, Jarjapu; Sowdhamini, Ramanathan

    2018-04-01

    The Toll-like receptors (TLRs) are critical components of the innate immune system due to their ability to detect conserved pathogen-associated molecular patterns, present in bacteria, viruses, and other microorganisms. Ligand detection by TLRs leads to a signaling cascade, mediated by interactions among TIR domains present in the receptors, the bridging adaptors and sorting adaptors. The BB loop is a highly conserved region present in the TIR domain and is crucial for mediating interactions among TIR domain-containing proteins. Mutations in the BB loop of the Toll-like receptors, such as the A795P mutation in TLR3 and the P712H mutation (Lps d mutation) in TLR4, have been reported to disrupt or alter downstream signaling. While the phenotypic effect of these mutations is known, the underlying effect of these mutations on the structure, dynamics and interactions with other TIR domain-containing proteins is not well understood. Here, we have attempted to investigate the effect of the BB loop mutations on the dimer form of TLRs, using TLR2 and TLR3 as case studies. Our results based on molecular dynamics simulations, protein-protein interaction analyses and protein structure network analyses highlight significant differences between the dimer interfaces of the wild-type and mutant forms and provide a logical reasoning for the effect of these mutations on adaptor binding to TLRs. Furthermore, it also leads us to propose a hypothesis for the differential requirement of signaling and bridging adaptors by TLRs. This could aid in further understanding of the mechanisms governing such signaling pathways. © 2018 Wiley Periodicals, Inc.

  13. Toll-like receptors and gastrointestinal diseases: from bench to bedside?

    PubMed

    Cario, Elke

    2002-11-01

    The family of Toll-like receptors (TLRs) plays a key role in mediating innate immune responses to numerous luminal commensal- and pathogen-derived pattern molecules by the intestinal mucosa. Recent findings have identified several ligands recognized by TLRs as well as the complex downstream signaling effects resulting from activation of these receptors. Understanding is emerging of the importance of TLRs in mucosal host defense-potentially triggering gastrointestinal diseases.

  14. Proteome and Secretome Analysis Reveals Differential Post-transcriptional Regulation of Toll-like Receptor Responses*

    PubMed Central

    Koppenol-Raab, Marijke; Sjoelund, Virginie; Manes, Nathan P.; Gottschalk, Rachel A.; Dutta, Bhaskar; Benet, Zachary L.; Fraser, Iain D. C.

    2017-01-01

    The innate immune system is the organism's first line of defense against pathogens. Pattern recognition receptors (PRRs) are responsible for sensing the presence of pathogen-associated molecules. The prototypic PRRs, the membrane-bound receptors of the Toll-like receptor (TLR) family, recognize pathogen-associated molecular patterns (PAMPs) and initiate an innate immune response through signaling pathways that depend on the adaptor molecules MyD88 and TRIF. Deciphering the differences in the complex signaling events that lead to pathogen recognition and initiation of the correct response remains challenging. Here we report the discovery of temporal changes in the protein signaling components involved in innate immunity. Using an integrated strategy combining unbiased proteomics, transcriptomics and macrophage stimulations with three different PAMPs, we identified differences in signaling between individual TLRs and revealed specifics of pathway regulation at the protein level. PMID:28235783

  15. Human Milk Components Modulate Toll-Like Receptor-Mediated Inflammation.

    PubMed

    He, YingYing; Lawlor, Nathan T; Newburg, David S

    2016-01-01

    Toll-like receptor (TLR) signaling is central to innate immunity. Aberrant expression of TLRs is found in neonatal inflammatory diseases. Several bioactive components of human milk modulate TLR expression and signaling pathways, including soluble toll-like receptors (sTLRs), soluble cluster of differentiation (sCD) 14, glycoproteins, small peptides, and oligosaccharides. Some milk components, such as sialyl (α2,3) lactose and lacto-N-fucopentaose III, are reported to increase TLR signaling; under some circumstances this might contribute toward immunologic balance. Human milk on the whole is strongly anti-inflammatory, and contains abundant components that depress TLR signaling pathways: sTLR2 and sCD14 inhibit TLR2 signaling; sCD14, lactadherin, lactoferrin, and 2'-fucosyllactose attenuate TLR4 signaling; 3'-galactosyllactose inhibits TLR3 signaling, and β-defensin 2 inhibits TLR7 signaling. Feeding human milk to neonates decreases their risk of sepsis and necrotizing enterocolitis. Thus, the TLR regulatory components found in human milk hold promise as benign oral prophylactic and therapeutic treatments for the many gastrointestinal inflammatory disorders mediated by abnormal TLR signaling. © 2016 American Society for Nutrition.

  16. Structural insights into pharmacophore-assisted in silico identification of protein-protein interaction inhibitors for inhibition of human toll-like receptor 4 - myeloid differentiation factor-2 (hTLR4-MD-2) complex.

    PubMed

    Mishra, Vinita; Pathak, Chandramani

    2018-05-29

    Toll-like receptor 4 (TLR4) is a member of Toll-Like Receptors (TLRs) family that serves as a receptor for bacterial lipopolysaccharide (LPS). TLR4 alone cannot recognize LPS without aid of co-receptor myeloid differentiation factor-2 (MD-2). Binding of LPS with TLR4 forms a LPS-TLR4-MD-2 complex and directs downstream signaling for activation of immune response, inflammation and NF-κB activation. Activation of TLR4 signaling is associated with various pathophysiological consequences. Therefore, targeting protein-protein interaction (PPI) in TLR4-MD-2 complex formation could be an attractive therapeutic approach for targeting inflammatory disorders. The aim of present study was directed to identify small molecule PPI inhibitors (SMPPIIs) using pharmacophore mapping-based approach of computational drug discovery. Here, we had retrieved the information about the hot spot residues and their pharmacophoric features at both primary (TLR4-MD-2) and dimerization (MD-2-TLR4*) protein-protein interaction interfaces in TLR4-MD-2 homo-dimer complex using in silico methods. Promising candidates were identified after virtual screening, which may restrict TLR4-MD-2 protein-protein interaction. In silico off-target profiling over the virtually screened compounds revealed other possible molecular targets. Two of the virtually screened compounds (C11 and C15) were predicted to have an inhibitory concentration in μM range after HYDE assessment. Molecular dynamics simulation study performed for these two compounds in complex with target protein confirms the stability of the complex. After virtual high throughput screening we found selective hTLR4-MD-2 inhibitors, which may have therapeutic potential to target chronic inflammatory diseases.

  17. A Toll/interleukin (IL)-1 receptor domain protein from Yersinia pestis interacts with mammalian IL-1/Toll-like receptor pathways but does not play a central role in the virulence of Y. pestis in a mouse model of bubonic plague.

    PubMed

    Spear, Abigail M; Rana, Rohini R; Jenner, Dominic C; Flick-Smith, Helen C; Oyston, Petra C F; Simpson, Peter; Matthews, Stephen J; Byrne, Bernadette; Atkins, Helen S

    2012-06-01

    The Toll/interleukin (IL)-1 receptor (TIR) domain is an essential component of eukaryotic innate immune signalling pathways. Interaction between TIR domains present in Toll-like receptors and associated adaptors initiates and propagates an immune signalling cascade. Proteins containing TIR domains have also been discovered in bacteria. Studies have subsequently shown that these proteins are able to modulate mammalian immune signalling pathways dependent on TIR interactions and that this may represent an evasion strategy for bacterial pathogens. Here, we investigate a TIR domain protein from the highly virulent bacterium Yersinia pestis, the causative agent of plague. When overexpressed in vitro this protein is able to downregulate IL-1β- and LPS-dependent signalling to NFκB and to interact with the TIR adaptor protein MyD88. This interaction is dependent on a single proline residue. However, a Y. pestis knockout mutant lacking the TIR domain protein was not attenuated in virulence in a mouse model of bubonic plague. Minor alterations in the host cytokine response to the mutant were indicated, suggesting a potential subtle role in pathogenesis. The Y. pestis mutant also showed increased auto-aggregation and reduced survival in high-salinity conditions, phenotypes which may contribute to pathogenesis or survival.

  18. Toll-6 and Toll-7 function as neurotrophin receptors in the Drosophila melanogaster CNS.

    PubMed

    McIlroy, Graham; Foldi, Istvan; Aurikko, Jukka; Wentzell, Jill S; Lim, Mei Ann; Fenton, Janine C; Gay, Nicholas J; Hidalgo, Alicia

    2013-09-01

    Neurotrophin receptors corresponding to vertebrate Trk, p75(NTR) or Sortilin have not been identified in Drosophila, thus it is unknown how neurotrophism may be implemented in insects. Two Drosophila neurotrophins, DNT1 and DNT2, have nervous system functions, but their receptors are unknown. The Toll receptor superfamily has ancient evolutionary origins and a universal function in innate immunity. Here we show that Toll paralogs unrelated to the mammalian neurotrophin receptors function as neurotrophin receptors in fruit flies. Toll-6 and Toll-7 are expressed in the CNS throughout development and regulate locomotion, motor axon targeting and neuronal survival. DNT1 (also known as NT1 and spz2) and DNT2 (also known as NT2 and spz5) interact genetically with Toll-6 and Toll-7, and DNT1 and DNT2 bind to Toll-6 and Toll-7 promiscuously and are distributed in vivo in domains complementary to or overlapping with those of Toll-6 and Toll-7. We conclude that in fruit flies, Tolls are not only involved in development and immunity but also in neurotrophism, revealing an unforeseen relationship between the neurotrophin and Toll protein families.

  19. Toll-like receptors (TLRs) and immune disorders.

    PubMed

    Akashi-Takamura, Sachiko; Miyake, Kensuke

    2006-10-01

    Upon the invasion of pathogens, the immune system needs to mount defense responses immediately. Over the past 10 years, Toll-like receptors (TLRs) have been discovered in mammals and defined as pathogen sensors. TLRs are considered to bind directly to ligands, discriminate them immediately, and induce defense responses when appropriate. We here review microbial recognition by TLRs, downstream signaling, and the relationship of TLRs to susceptibility to infectious diseases and immune disorders. Recent reports have revealed a requirement for co-receptors in TLR responses. A TLR signaling pathway is required for protection against infectious diseases, but excessive signaling may lead to allergies, autoimmune diseases, or atherosclerosis. In humans, several deficiencies of signaling molecules downstream of TLRs, and TLR polymorphisms that affect recognition or signaling, were reported to cause immunodeficiencies. It is important to understand how TLR signaling is controlled.

  20. Toll-like receptor signaling and stages of addiction.

    PubMed

    Crews, Fulton T; Walter, T Jordan; Coleman, Leon G; Vetreno, Ryan P

    2017-05-01

    Athina Markou and her colleagues discovered persistent changes in adult behavior following adolescent exposure to ethanol or nicotine consistent with increased risk for developing addiction. Building on Dr. Markou's important work and that of others in the field, researchers at the Bowles Center for Alcohol Studies have found that persistent changes in behavior following adolescent stress or alcohol exposure may be linked to induction of immune signaling in brain. This study aims to illuminate the critical interrelationship of the innate immune system (e.g., toll-like receptors [TLRs], high-mobility group box 1 [HMGB1]) in the neurobiology of addiction. This study reviews the relevant research regarding the relationship between the innate immune system and addiction. Emerging evidence indicates that TLRs in brain, particularly those on microglia, respond to endogenous innate immune agonists such as HMGB1 and microRNAs (miRNAs). Multiple TLRs, HMGB1, and miRNAs are induced in the brain by stress, alcohol, and other drugs of abuse and are increased in the postmortem human alcoholic brain. Enhanced TLR-innate immune signaling in brain leads to epigenetic modifications, alterations in synaptic plasticity, and loss of neuronal cell populations, which contribute to cognitive and emotive dysfunctions. Addiction involves progressive stages of drug binges and intoxication, withdrawal-negative affect, and ultimately compulsive drug use and abuse. Toll-like receptor signaling within cortical-limbic circuits is modified by alcohol and stress in a manner consistent with promoting progression through the stages of addiction.

  1. Sleep deprivation and divergent toll-like receptor-4 activation of cellular inflammation in aging.

    PubMed

    Carroll, Judith E; Carrillo, Carmen; Olmstead, Richard; Witarama, Tuff; Breen, Elizabeth C; Yokomizo, Megumi; Seeman, Teresa; Irwin, Michael R

    2015-02-01

    Sleep disturbance and aging are associated with increases in inflammation, as well as increased risk of infectious disease. However, there is limited understanding of the role of sleep loss on age-related differences in immune responses. This study examines the effects of sleep deprivation on toll-like receptor activation of monocytic inflammation in younger compared to older adults. Community-dwelling adults (n = 70) who were categorized as younger (25-39 y old, n = 21) and older (60-84 y old, n = 49) participants, underwent a sleep laboratory-based experimental partial sleep deprivation (PSD) protocol including adaptation, an uninterrupted night of sleep, sleep deprivation (sleep restricted to 03:00-07:00), and recovery. Blood samples were obtained each morning to measure toll-like receptor-4 activation of monocyte intracellular production of the inflammatory cytokines interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α). Partial sleep deprivation induced a significant increase in the production of IL-6 and/or TNF-α that persisted after a night of recovery sleep (F(2,121.2) = 3.8, P < 0.05). Age moderated the effects of sleep loss, such that younger adults had an increase in inflammatory cytokine production that was not present in older adults (F(2,121.2) = 4.0, P < 0.05). Older adults exhibit reduced toll-like receptor 4 stimulated cellular inflammation that, unlike in younger adults, is not activated after a night of partial sleep loss. Whereas sleep loss increases cellular inflammation in younger adults and may contribute to inflammatory disorders, blunted toll-like receptor activation in older adults may increase the risk of infectious disease seen with aging. © 2015 Associated Professional Sleep Societies, LLC.

  2. Specificity in Toll-like receptor signalling through distinct effector functions of TRAF3 and TRAF6.

    PubMed

    Häcker, Hans; Redecke, Vanessa; Blagoev, Blagoy; Kratchmarova, Irina; Hsu, Li-Chung; Wang, Gang G; Kamps, Mark P; Raz, Eyal; Wagner, Hermann; Häcker, Georg; Mann, Matthias; Karin, Michael

    2006-01-12

    Toll-like receptors (TLRs) are activated by pathogen-associated molecular patterns to induce innate immune responses and production of pro-inflammatory cytokines, interferons and anti-inflammatory cytokines. TLRs activate downstream effectors through adaptors that contain Toll/interleukin-1 receptor (TIR) domains, but the mechanisms accounting for diversification of TLR effector functions are unclear. To dissect biochemically TLR signalling, we established a system for isolating signalling complexes assembled by dimerized adaptors. Using MyD88 as a prototypical adaptor, we identified TNF receptor-associated factor 3 (TRAF3) as a new component of TIR signalling complexes that is recruited along with TRAF6. Using myeloid cells from TRAF3- and TRAF6-deficient mice, we show that TRAF3 is essential for the induction of type I interferons (IFN) and the anti-inflammatory cytokine interleukin-10 (IL-10), but is dispensable for expression of pro-inflammatory cytokines. In fact, TRAF3-deficient cells overproduce pro-inflammatory cytokines owing to defective IL-10 production. Despite their structural similarity, the functions of TRAF3 and TRAF6 are largely distinct. TRAF3 is also recruited to the adaptor TRIF (Toll/IL-1 receptor domain-containing adaptor-inducing IFN-beta) and is required for marshalling the protein kinase TBK1 (also called NAK) into TIR signalling complexes, thereby explaining its unique role in activation of the IFN response.

  3. Roles of Toll-like receptors in allogeneic islet transplantation.

    PubMed

    Ro, Han; Hong, Juho; Kim, Beom Seok; Lee, Eun Won; Kim, Myung-Gyu; Han, Kyu Hyun; Yeom, Hye-Jung; Lee, Eun Mi; Jeong, Jong Cheol; Oh, Kook-Hwan; Ahn, Curie; Yang, Jaeseok

    2012-11-27

    Toll-like receptors (TLRs) are involved in the rejection of solid organ allografts. However, the roles of TLRs in islets are still controversial. We investigated the roles of TLRs in donor islets together with those in recipients in allogeneic islet transplantation. To assess the roles of TLRs in either donor islets or recipients, allogeneic islet transplantation was performed using myeloid differentiation factor 88 (MyD88)-knockout (KO), TLR4-KO, or Toll/interleukin-1 receptor domain-containing adaptor-inducing interferon-β (TRIF)-KO mice. Both polyriboinosinic polyribocytidylic acid and lipopolysaccharide (LPS) stimulation induced the mRNA expression of regulated and normal T cell expressed and secreted, interferon-γ-inducible protein-10, monocyte chemotactic protein-1, interleukin-8, and inducible nitric oxide synthase in murine islets, whereas the induction was attenuated in TRIF-KO, interferon-β promoter stimulator-1-KO, and TLR4-KO mice. When islets from MyD88-KO, TLR4-KO, or TRIF-KO C57BL/6 mice were transplanted to BALB/c recipients, graft survival was not better than that of wild-type (WT) islets. However, the survival of the MyD88-KO islet allograft was significantly prolonged when combined with anti-CD40L. In parallel, LPS stimulation in donor islets interfered with anti-CD40L blockade-mediated long-term survival of islet allografts in TLR4-KO recipients. LPS stimulation increased the perigraft infiltration of both T cells and macrophages. Then again, when islets from WT BALB/c mice were transplanted to MyD88-KO, TRIF-KO, or WT C57BL/6 mice, there was no difference in graft survival, although some of the MyD88-KO recipients obtained long-term graft survival. However, anti-CD40L prolonged graft survival significantly in MyD88-KO recipients. The absence of MyD88 in either donors or recipients decreased the perigraft infiltration of inflammatory cells when combined with anti-CD40L. TLRs in both donor islets and recipients are involved in islet allograft

  4. Toll-like receptor-2 deficiency induces schizophrenia-like behaviors in mice

    PubMed Central

    Park, Se Jin; Lee, Jee Youn; Kim, Sang Jeong; Choi, Se-Young; Yune, Tae Young; Ryu, Jong Hoon

    2015-01-01

    Dysregulation of the immune system contributes to the pathogenesis of neuropsychiatric disorders including schizophrenia. Here, we demonstrated that toll-like receptor (TLR)-2, a family of pattern-recognition receptors, is involved in the pathogenesis of schizophrenia-like symptoms. Psychotic symptoms such as hyperlocomotion, anxiolytic-like behaviors, prepulse inhibition deficits, social withdrawal, and cognitive impairments were observed in TLR-2 knock-out (KO) mice. Ventricle enlargement, a hallmark of schizophrenia, was also observed in TLR-2 KO mouse brains. Levels of p-Akt and p-GSK-3α/β were markedly higher in the brain of TLR-2 KO than wild-type (WT) mice. Antipsychotic drugs such as haloperidol or clozapine reversed behavioral and biochemical alterations in TLR-2 KO mice. Furthermore, p-Akt and p-GSK-3α/β were decreased by treatment with a TLR-2 ligand, lipoteichoic acid, in WT mice. Thus, our data suggest that the dysregulation of the innate immune system by a TLR-2 deficiency may contribute to the development and/or pathophysiology of schizophrenia-like behaviors via Akt-GSK-3α/β signaling. PMID:25687169

  5. Mycobacterium avium MAV2052 protein induces apoptosis in murine macrophage cells through Toll-like receptor 4.

    PubMed

    Lee, Kang-In; Choi, Han-Gyu; Son, Yeo-Jin; Whang, Jake; Kim, Kwangwook; Jeon, Heat Sal; Park, Hye-Soo; Back, Yong Woo; Choi, Seunga; Kim, Seong-Woo; Choi, Chul Hee; Kim, Hwa-Jung

    2016-04-01

    Mycobacterium avium and its sonic extracts induce apoptosis in macrophages. However, little is known about the M. avium components regulating macrophage apoptosis. In this study, using multidimensional fractionation, we identified MAV2052 protein, which induced macrophage apoptosis in M. avium culture filtrates. The recombinant MAV2052 induced macrophage apoptosis in a caspase-dependent manner. The loss of mitochondrial transmembrane potential (ΔΨm), mitochondrial translocation of Bax, and release of cytochrome c from mitochondria were observed in macrophages treated with MAV2052. Further, reactive oxygen species (ROS) production was required for the apoptosis induced by MAV2052. In addition, ROS and mitogen-activated protein kinases were involved in MAV2052-mediated TNF-α and IL-6 production. ROS-mediated activation of apoptosis signal-regulating kinase 1 (ASK1)-JNK pathway was a major signaling pathway for MAV2052-induced apoptosis. Moreover, MAV2052 bound to Toll-like receptor (TLR) 4 molecule and MAV2052-induced ROS production, ΔΨm loss, and apoptosis were all significantly reduced in TLR4(-/-) macrophages. Altogether, our results suggest that MAV2052 induces apoptotic cell death through TLR4 dependent ROS production and JNK pathway in murine macrophages.

  6. Toll-like receptor signaling in cell proliferation and survival

    PubMed Central

    Li, Xinyan; Jiang, Song; Tapping, Richard I.

    2009-01-01

    Toll-like receptors (TLRs) are important sensors of foreign microbial components as well as products of damaged or inflamed self tissues. Upon sensing these molecules, TLRs initiate a series of downstream signaling events that drive cellular responses including the production of cytokines, chemokines and other inflammatory mediators. This outcome results from the intracellular assembly of protein complexes that drive phosphorylation and other signaling cascades ultimately leading to chromatin remodeling and transcription factor activation. In addition to driving inflammatory responses, TLRs also regulate cell proliferation and survival which serves to expand useful immune cells and integrate inflammatory responses and tissue repair processes. In this context, central TLR signaling molecules, such as the mitogen-activated protein kinases (MAPK) and phosphoinositide 3-kinase (PI3K), play key roles. In addition, four major groups of transcription factors which are targets of TLR activation also control cell fate. This review focuses on the role of TLR signaling as it relates to cell proliferation and survival. This topic not only has important implications for understanding host defense and tissue repair, but also cancer which is often associated with conditions of chronic inflammation. PMID:19775907

  7. Energetics of Endotoxin Recognition in the Toll-Like Receptor 4 Innate Immune Response.

    PubMed

    Paramo, Teresa; Tomasio, Susana M; Irvine, Kate L; Bryant, Clare E; Bond, Peter J

    2015-12-09

    Bacterial outer membrane lipopolysaccharide (LPS) potently stimulates the mammalian innate immune system, and can lead to sepsis, the primary cause of death from infections. LPS is sensed by Toll-like receptor 4 (TLR4) in complex with its lipid-binding coreceptor MD-2, but subtle structural variations in LPS can profoundly modulate the response. To better understand the mechanism of LPS-induced stimulation and bacterial evasion, we have calculated the binding affinity to MD-2 of agonistic and antagonistic LPS variants including lipid A, lipid IVa, and synthetic antagonist Eritoran, and provide evidence that the coreceptor is a molecular switch that undergoes ligand-induced conformational changes to appropriately activate or inhibit the receptor complex. The plasticity of the coreceptor binding cavity is shown to be essential for distinguishing between ligands, whilst similar calculations for a model bacterial LPS bilayer reveal the "membrane-like" nature of the protein cavity. The ability to predict the activity of LPS variants should facilitate the rational design of TLR4 therapeutics.

  8. Targeting Toll-like receptor (TLR) signaling by Toll/interleukin-1 receptor (TIR) domain-containing adapter protein/MyD88 adapter-like (TIRAP/Mal)-derived decoy peptides.

    PubMed

    Couture, Leah A; Piao, Wenji; Ru, Lisa W; Vogel, Stefanie N; Toshchakov, Vladimir Y

    2012-07-13

    Toll/interleukin-1 receptor (TIR) domain-containing adapter protein/MyD88 adapter-like (TIRAP/Mal) is an adapter protein that facilitates recruitment of MyD88 to TLR4 and TLR2 signaling complexes. We previously generated a library of cell-permeating TLR4 TIR-derived decoy peptides fused to the translocating segment of the Drosophila Antennapedia homeodomain and examined each peptide for the ability to inhibit TLR4 signaling (Toshchakov, V. Y., Szmacinski, H., Couture, L. A., Lakowicz, J. R., and Vogel, S. N. (2011) J. Immunol. 186, 4819-4827). We have now expanded this study to test TIRAP decoy peptides. Five TIRAP peptides, TR3 (for TIRAP region 3), TR5, TR6, TR9, and TR11, inhibited LPS-induced cytokine mRNA expression and MAPK activation. Inhibition was confirmed at the protein level; select peptides abolished the LPS-induced cytokine production measured in cell culture 24 h after a single treatment. Two of the TLR4 inhibitory peptides, TR3 and TR6, also inhibited cytokine production induced by a TLR2/TLR1 agonist, S-(2,3-bis(palmitoyloxy)-(2R,2S)-propyl)-N-palmitoyl-(R)-Cys-Ser-Lys(4)-OH; however, a higher peptide concentration was required to achieve comparable inhibition of TLR2 versus TLR4 signaling. Two TLR4 inhibitory peptides, TR5 and TR6, were examined for the ability to inhibit TLR4-driven cytokine induction in mice. Pretreatment with either peptide significantly reduced circulating TNF-α and IL-6 in mice following LPS injection. This study has identified novel TLR inhibitory peptides that block cellular signaling at low micromolar concentrations in vitro and in vivo. Comparison of TLR4 inhibition by TLR4 and TIRAP TIR-derived peptides supports the view that structurally diverse regions mediate functional interactions of TIR domains.

  9. Toll-like receptors and intestinal defence: molecular basis and therapeutic implications.

    PubMed

    Cario, Elke

    2003-07-07

    Toll-like receptors (TLRs) play a principle role in distinct pathogen recognition and in the initiation of innate immune responses of the intestinal mucosa. Activated innate immunity interconnects downstream with adaptive immunity in complex feedback regulatory loops. Intestinal disease might result from inappropriate activation of the mucosal immune system driven by TLRs in response to normal luminal flora.

  10. Burn Enhances Toll-Like Receptor Induced Responses by Circulating Leukocytes

    DTIC Science & Technology

    2012-04-30

    Introduction Major burn is associated with a local and sys- temic activation of the innate immune system resulting in a profound inflammatory...plications. Previous studies have shown that responses after burn differ between fixed-tissue immune cells and circulating immune cells [15]. In the current...Abstract: Burn and toll-like receptors (TLR) are associated with innate immune system activation, but the impact of burn on TLR-induced inflammation

  11. Toll-like receptor signaling: a perspective to develop vaccine against leishmaniasis.

    PubMed

    Singh, Rakesh K; Srivastava, Ankita; Singh, Nisha

    2012-09-06

    The toll-like receptors (TLRs) are the sentinel factor of the innate immunity, which are essential for host defense. These receptors detect the presence of conserved molecular patterns of potentially pathogenic microorganisms and contribute in both, cellular as well as humoral immune responses. Leishmania is an intracellular pathogen that silently invades host immune system. After phagocytosis, it divides and proliferates in the harmful environment of host macrophages by down-regulating its vital effector functions. In leishmaniasis, the outcome of the infection basically relies on the skewed balance between Th1/Th2 immune responses. Lots of work have been done and on progress but still characterization of either preventive or prophylactic candidate antigen/s is far from satisfactory. How does Leishmania regulate host innate immune system? Still it is unanswered. TLRs play very important role during inflammatory process of various diseases such as cancer, bacterial and viral infections but TLR signaling is comparatively less explained in leishmanial infection. In the context to Th1/Th2 dichotomy, identification of leishmanial antigens that modulate toll-like receptor signaling will certainly help in the development of future vaccine. This review will initially describe global properties of TLRs, and later will discuss their role in the pathogenesis of leishmaniasis. Copyright © 2012 Elsevier GmbH. All rights reserved.

  12. Toll-Like Receptors in Secondary Obstructive Cholangiopathy

    PubMed Central

    Miranda-Díaz, A. G.; Alonso-Martínez, H.; Hernández-Ojeda, J.; Arias-Carvajal, O.; Rodríguez-Carrizalez, A. D.; Román-Pintos, L. M.

    2011-01-01

    Secondary obstructive cholangiopathy is characterized by intra- or extrahepatic bile tract obstruction. Liver inflammation and structural alterations develop due to progressive bile stagnation. Most frequent etiologies are biliary atresia in children, and hepatolithiasis, postcholecystectomy bile duct injury, and biliary primary cirrhosis in adults, which causes chronic biliary cholangitis. Bile ectasia predisposes to multiple pathogens: viral infections in biliary atresia; Gram-positive and/or Gram-negative bacteria cholangitis found in hepatolithiasis and postcholecystectomy bile duct injury. Transmembrane toll-like receptors (TLRs) are activated by virus, bacteria, fungi, and parasite stimuli. Even though TLR-2 and TLR-4 are the most studied receptors related to liver infectious diseases, other TLRs play an important role in response to microorganism damage. Acquired immune response is not vertically transmitted and reflects the infectious diseases history of individuals; in contrast, innate immunity is based on antigen recognition by specific receptors designated as pattern recognition receptors and is transmitted vertically through the germ cells. Understanding the mechanisms for bile duct inflammation is essential for the future development of therapeutic alternatives in order to avoid immune-mediated destruction on secondary obstructive cholangiopathy. The role of TLRs in biliary atresia, hepatolithiasis, bile duct injury, and primary biliary cirrhosis is described in this paper. PMID:22114589

  13. Toll-Like Receptor Signaling Induces Nrf2 Pathway Activation through p62-Triggered Keap1 Degradation.

    PubMed

    Yin, Shasha; Cao, Wangsen

    2015-08-01

    Toll-like receptors (TLRs) induce inflammation and tissue repair through multiple signaling pathways. The Nrf2 pathway plays a key role in defending against the tissue damage incurred by microbial infection or inflammation-associated diseases. The critical event that mediates TLR-induced Nrf2 activation is still poorly understood. In this study, we found that lipopolysaccharide (LPS) and other Toll-like receptor (TLR) agonists activate Nrf2 signaling and the activation is due to the reduction of Keap1, the key Nrf2 inhibitor. TLR signaling-induced Keap1 reduction promoted Nrf2 translocation from the cytoplasm to the nucleus, where it activated transcription of its target genes. TLR agonists modulated Keap1 at the protein posttranslation level through autophagy. TLR signaling increased the expression of autophagy protein p62 and LC3-II and induced their association with Keap1 in the autophagosome-like structures. We also characterized the interaction between p62 and Keap1 and found that p62 is indispensable for TLR-mediated Keap1 reduction: TLR signaling had no effect on Keap1 if cells lacked p62 or if cells expressed a mutant Keap1 that could not interact with p62. Our study indicates that p62-mediated Keap1 degradation through autophagy represents a critical linkage for TLR signaling regulation of the major defense network, the Nrf2 signaling pathway. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  14. Hepatocyte Toll-like receptor 4 regulates obesity-induced inflammation and insulin resistance

    USDA-ARS?s Scientific Manuscript database

    Chronic low-grade inflammation is a hallmark of obesity and thought to contribute to the development of obesity-related insulin resistance. Toll-like receptor 4 (Tlr4) is a key mediator of pro-inflammatory responses. Mice lacking Tlr4s are protected from diet-induced insulin resistance and inflammat...

  15. Toll-Like Receptor Stimulation Induces Nondefensin Protein Expression and Reverses Antibiotic-Induced Gut Defense Impairment

    PubMed Central

    Wu, Ying-Ying; Hsu, Ching-Mei; Chen, Pei-Hsuan; Fung, Chang-Phone

    2014-01-01

    Prior antibiotic exposure is associated with increased mortality in Gram-negative bacteria-induced sepsis. However, how antibiotic-mediated changes of commensal bacteria promote the spread of enteric pathogenic bacteria in patients remains unclear. In this study, the effects of systemic antibiotic treatment with or without Toll-like receptor (TLR) stimulation on bacterium-killing activity, antibacterial protein expression in the intestinal mucosa, and bacterial translocation were examined in mice receiving antibiotics with or without oral supplementation of dead Escherichia coli or Staphylococcus aureus. We developed a systemic ampicillin, vancomycin, and metronidazole treatment protocol to simulate the clinical use of antibiotics. Antibiotic treatment decreased the total number of bacteria, including aerobic bacteria belonging to the family Enterobacteriaceae and the genus Enterococcus as well as organisms of the anaerobic genera Lactococcus and Bifidobacterium in the intestinal mucosa and lumen. Antibiotic treatment significantly decreased the bacterium-killing activity of the intestinal mucosa and the expression of non-defensin-family proteins, such as RegIIIβ, RegIIIγ, C-reactive protein-ductin, and RELMβ, but not the defensin-family proteins, and increased Klebsiella pneumoniae translocation. TLR stimulation after antibiotic treatment increased NF-κB DNA binding activity, nondefensin protein expression, and bacterium-killing activity in the intestinal mucosa and decreased K. pneumoniae translocation. Moreover, germfree mice showed a significant decrease in nondefensin proteins as well as intestinal defense against pathogen translocation. Since TLR stimulation induced NF-κB DNA binding activity, TLR4 expression, and mucosal bacterium-killing activity in germfree mice, we conclude that the commensal microflora is critical in maintaining intestinal nondefensin protein expression and the intestinal barrier. In turn, we suggest that TLR stimulation induces

  16. Toll-like receptor stimulation induces nondefensin protein expression and reverses antibiotic-induced gut defense impairment.

    PubMed

    Wu, Ying-Ying; Hsu, Ching-Mei; Chen, Pei-Hsuan; Fung, Chang-Phone; Chen, Lee-Wei

    2014-05-01

    Prior antibiotic exposure is associated with increased mortality in Gram-negative bacteria-induced sepsis. However, how antibiotic-mediated changes of commensal bacteria promote the spread of enteric pathogenic bacteria in patients remains unclear. In this study, the effects of systemic antibiotic treatment with or without Toll-like receptor (TLR) stimulation on bacterium-killing activity, antibacterial protein expression in the intestinal mucosa, and bacterial translocation were examined in mice receiving antibiotics with or without oral supplementation of dead Escherichia coli or Staphylococcus aureus. We developed a systemic ampicillin, vancomycin, and metronidazole treatment protocol to simulate the clinical use of antibiotics. Antibiotic treatment decreased the total number of bacteria, including aerobic bacteria belonging to the family Enterobacteriaceae and the genus Enterococcus as well as organisms of the anaerobic genera Lactococcus and Bifidobacterium in the intestinal mucosa and lumen. Antibiotic treatment significantly decreased the bacterium-killing activity of the intestinal mucosa and the expression of non-defensin-family proteins, such as RegIIIβ, RegIIIγ, C-reactive protein-ductin, and RELMβ, but not the defensin-family proteins, and increased Klebsiella pneumoniae translocation. TLR stimulation after antibiotic treatment increased NF-κB DNA binding activity, nondefensin protein expression, and bacterium-killing activity in the intestinal mucosa and decreased K. pneumoniae translocation. Moreover, germfree mice showed a significant decrease in nondefensin proteins as well as intestinal defense against pathogen translocation. Since TLR stimulation induced NF-κB DNA binding activity, TLR4 expression, and mucosal bacterium-killing activity in germfree mice, we conclude that the commensal microflora is critical in maintaining intestinal nondefensin protein expression and the intestinal barrier. In turn, we suggest that TLR stimulation induces

  17. [Toll-like receptor in lung response to pathogens].

    PubMed

    Rivas-Santiago, Bruno; Juárez, Esmeralda

    2007-01-01

    Innate immunity plays a central role in antimicrobial defense. Advances in the understanding of pathogen recognition systems of innate cells have yielded the identification of Toll like receptors (TLR) as key elements of the lung defense mechanisms which is heavily exposed to a variety of stimuli. TLR recognition of several microbial compounds induces proinflammatory cytokines production whose contribution to the host may be either protective or detrimental. Human immune response diversity may explain the differences observed between patients facing bacterial, viral and fungal lung infections. New strategies designs that modify innate immune response may be useful to limit detrimental consequences of inflammatory processes in the lung.

  18. Toll-like receptor signaling and its relevance to intestinal inflammation.

    PubMed

    Cario, Elke; Podolsky, Daniel K

    2006-08-01

    This review discusses the current progress in the understanding of how commensal-mediated activation of toll-like receptors (TLRs) may be involved in the regulation of physiological and pathophysiological processes of the intestinal mucosa including tissue regeneration and inflammation. While regulation of TLRs and their downstream signaling mediators might be used to prevent and treat inflammatory bowel diseases, paradoxically, at this time, it remains uncertain whether this would be more effectively accomplished by enhancing or inhibiting these pathways.

  19. AP1S3 Mutations Are Associated with Pustular Psoriasis and Impaired Toll-like Receptor 3 Trafficking

    PubMed Central

    Setta-Kaffetzi, Niovi; Simpson, Michael A.; Navarini, Alexander A.; Patel, Varsha M.; Lu, Hui-Chun; Allen, Michael H.; Duckworth, Michael; Bachelez, Hervé; Burden, A. David; Choon, Siew-Eng; Griffiths, Christopher E.M.; Kirby, Brian; Kolios, Antonios; Seyger, Marieke M.B.; Prins, Christa; Smahi, Asma; Trembath, Richard C.; Fraternali, Franca; Smith, Catherine H.; Barker, Jonathan N.; Capon, Francesca

    2014-01-01

    Adaptor protein complex 1 (AP-1) is an evolutionary conserved heterotetramer that promotes vesicular trafficking between the trans-Golgi network and the endosomes. The knockout of most murine AP-1 complex subunits is embryonically lethal, so the identification of human disease-associated alleles has the unique potential to deliver insights into gene function. Here, we report two founder mutations (c.11T>G [p.Phe4Cys] and c.97C>T [p.Arg33Trp]) in AP1S3, the gene encoding AP-1 complex subunit σ1C, in 15 unrelated individuals with a severe autoinflammatory skin disorder known as pustular psoriasis. Because the variants are predicted to destabilize the 3D structure of the AP-1 complex, we generated AP1S3-knockdown cell lines to investigate the consequences of AP-1 deficiency in skin keratinocytes. We found that AP1S3 silencing disrupted the endosomal translocation of the innate pattern-recognition receptor TLR-3 (Toll-like receptor 3) and resulted in a marked inhibition of downstream signaling. These findings identify pustular psoriasis as an autoinflammatory phenotype caused by defects in vesicular trafficking and demonstrate a requirement of AP-1 for Toll-like receptor homeostasis. PMID:24791904

  20. Regulation of dendritic cell function through Toll-like receptors.

    PubMed

    Kaisho, Tsuneyasu; Akira, Shizuo

    2003-06-01

    Higher animals establish host defense by orchestrating innate and adaptive immunity. This is mediated by professional antigen presenting cells, i.e. dendritic cells (DCs). DCs can incorporate pathogens, produce a variety of cytokines, maturate, and present pathogen-derived peptides to T cells, thereby inducing T cell activation and differentiation. These responses are triggered by microbial recognition through type I transmembrane proteins, Toll-like receptors (TLRs) on DCs. TLRs consist of ten members and each TLR is involved in recognizing a variety of microorganism-derived molecular structures. TLR ligands include cell wall components, proteins, nucleic acids, and synthetic chemical compounds, all of which can activate DCs as immune adjuvants. Each TLR can activate DCs in a similar, but distinct manner. For example, TLRs can be divided into subgroups according to their type I interferon (IFN) inducing ability. TLR2 cannot induce IFN-alpha or IFN-beta, but TLR4 can lead to IFN-beta production. Meanwhile, TLR3, TLR7, and TLR9 can induce both IFN-alpha and IFN-beta. Recent evidences suggest that cytoplamic adapters for TLRs are especially crucial for this functional heterogeneity. Clarifying how DC function is regulated by TLRs should provide us with critical information for manipulating the host defense against a variety of diseases.

  1. Enrichment assessment of multiple virtual screening strategies for Toll-like receptor 8 agonists based on a maximal unbiased benchmarking data set.

    PubMed

    Pei, Fen; Jin, Hongwei; Zhou, Xin; Xia, Jie; Sun, Lidan; Liu, Zhenming; Zhang, Liangren

    2015-11-01

    Toll-like receptor 8 agonists, which activate adaptive immune responses by inducing robust production of T-helper 1-polarizing cytokines, are promising candidates for vaccine adjuvants. As the binding site of toll-like receptor 8 is large and highly flexible, virtual screening by individual method has inevitable limitations; thus, a comprehensive comparison of different methods may provide insights into seeking effective strategy for the discovery of novel toll-like receptor 8 agonists. In this study, the performance of knowledge-based pharmacophore, shape-based 3D screening, and combined strategies was assessed against a maximum unbiased benchmarking data set containing 13 actives and 1302 decoys specialized for toll-like receptor 8 agonists. Prior structure-activity relationship knowledge was involved in knowledge-based pharmacophore generation, and a set of antagonists was innovatively used to verify the selectivity of the selected knowledge-based pharmacophore. The benchmarking data set was generated from our recently developed 'mubd-decoymaker' protocol. The enrichment assessment demonstrated a considerable performance through our selected three-layer virtual screening strategy: knowledge-based pharmacophore (Phar1) screening, shape-based 3D similarity search (Q4_combo), and then a Gold docking screening. This virtual screening strategy could be further employed to perform large-scale database screening and to discover novel toll-like receptor 8 agonists. © 2015 John Wiley & Sons A/S.

  2. Postconditioning: "Toll-erating" mesenteric ischemia-reperfusion injury?

    PubMed

    Rosero, Olivér; Ónody, Péter; Kovács, Tibor; Molnár, Dávid; Fülöp, András; Lotz, Gábor; Harsányi, László; Szijártó, Attila

    2017-04-01

    Postconditioning may prove to be a suitable method to decrease ischemia-reperfusion injury of intestine after mesenteric arterial occlusion. Toll-like-receptor-4 is involved in the pathophysiology of organ damage after ischemia-reperfusion; therefore, the aim of our study was to investigate the effect of postconditioning on the mucosal expression of toll-like-receptor-4. Male Wistar rats (n = 10/group) underwent 60 minutes of superior mesenteric artery occlusion followed by 6 hours of reperfusion in 3 groups: sham-operated, ischemia-reperfusion, and a postconditioned group. Postconditioning was performed by 6 alternating cycles of 10 seconds of reperfusion/reocclusion. Blood and tissue samples were collected at the end of reperfusion. Intestinal histopathologic changes and immunohistochemical expression of mucosal caspase-3, antioxidant status, and protein levels of high-mobility group box-1 and toll-like-receptor-4 were assessed. Immunofluorescent labeling and confocal microscopic analysis of toll-like-receptor-4 were performed. Mucosal and serum levels of interleukin-6 and tumor necrosis factor-α protein were measured. Histologic alterations in the postconditioned group were associated with decreased caspase-3 positivity, less toll-like-receptor-4 mRNA, and less protein expression of high-mobility group box-1 and toll-like-receptor-4 in the intestinal villi compared with the ischemia-reperfusion group. Furthermore, a significantly improved antioxidant state of the intestinal mucosa and less mucosal and serum protein levels of interleukin-6 and tumor necrosis factor-α were detected in the postconditioned group. Small intestinal ischemia-reperfusion injury in male Wistar rats caused by the occlusion of the superior mesenteric artery was ameliorated by the use of postconditioning, showing a more favorable inflammatory response, which may be attributed to the decreased mucosal expression of toll-like-receptor-4. Copyright © 2016 Elsevier Inc. All rights

  3. In Celiac Disease, a Subset of Autoantibodies against Transglutaminase Binds Toll-Like Receptor 4 and Induces Activation of Monocytes

    PubMed Central

    Tridente, Giuseppe; Bason, Caterina; Sivori, Simona; Beri, Ruggero; Dolcino, Marzia; Valletta, Enrico; Corrocher, Roberto; Puccetti, Antonio

    2006-01-01

    Background Celiac disease is a small intestine inflammatory disorder with multiple organ involvement, sustained by an inappropriate immune response to dietary gluten. Anti-transglutaminase antibodies are a typical serological marker in patients with active disease, and may disappear during a gluten-free diet treatment. Involvement of infectious agents and innate immunity has been suggested but never proven. Molecular mimicry is one of the mechanisms that links infection and autoimmunity. Methods and Findings In our attempt to clarify the pathogenesis of celiac disease, we screened a random peptide library with pooled sera of patients affected by active disease after a pre-screening with the sera of the same patients on a gluten-free diet. We identified a peptide recognized by serum immunoglobulins of patients with active disease, but not by those of patients on a gluten-free diet. This peptide shares homology with the rotavirus major neutralizing protein VP-7 and with the self-antigens tissue transglutaminase, human heat shock protein 60, desmoglein 1, and Toll-like receptor 4. We show that antibodies against the peptide affinity-purified from the sera of patients with active disease recognize the viral product and self-antigens in ELISA and Western blot. These antibodies were able to induce increased epithelial cell permeability evaluated by transepithelial flux of [3H] mannitol in the T84 human intestinal epithelial cell line. Finally, the purified antibodies induced monocyte activation upon binding Toll-like receptor 4, evaluated both by surface expression of activation markers and by production of pro-inflammatory cytokines. Conclusions Our findings show that in active celiac disease, a subset of anti-transglutaminase IgA antibodies recognize the viral protein VP-7, suggesting a possible involvement of rotavirus infection in the pathogenesis of the disease, through a mechanism of molecular mimicry. Moreover, such antibodies recognize self-antigens and are

  4. Patents for Toll-like receptor ligands as radiation countermeasures for acute radiation syndrome.

    PubMed

    Singh, Vijay K; Pollard, Harvey B

    2015-01-01

    Acute radiation exposure induces apoptosis of tissues in the hematopoietic, digestive, cutaneous, cardiovascular and nervous systems; extensive apoptosis of these tissues ultimately leads to acute radiation syndrome. A novel strategy for developing radiation countermeasures has been to imitate the genetic mechanisms acquired by radiation-resistant tumors. Two mechanisms that underlie this ability of tumor cells are the p53 and NF-κB pathways. The loss of p53 function results in the inactivation of pro-apoptotic control mechanisms, while constitutive activation of NF-κB results in the up-regulation of anti-apoptotic genes. Various Toll-like receptor ligands are capable of up regulating the NF-κB pathway, which increases radio-resistance and reduces radiation-induced apoptosis in various tissues. Several Toll-like receptor ligands have been patented and are currently under development as radiation countermeasures for acute radiation syndrome. Ongoing studies suggest that a few of these attractive agents are progressing well along the US FDA approval pathway to become radiation countermeasures.

  5. Patents for Toll-like receptor ligands as radiation countermeasures for acute radiation syndrome

    PubMed Central

    Singh, Vijay K; Pollard, Harvey B

    2015-01-01

    Acute radiation exposure induces apoptosis of tissues in the hematopoietic, digestive, cutaneous, cardiovascular and nervous systems; extensive apoptosis of these tissues ultimately leads to acute radiation syndrome. A novel strategy for developing radiation countermeasures has been to imitate the genetic mechanisms acquired by radiation-resistant tumors. Two mechanisms that underlie this ability of tumor cells are the p53 and NF-κB pathways. The loss of p53 function results in the inactivation of pro-apoptotic control mechanisms, while constitutive activation of NF-κB results in the up-regulation of anti-apoptotic genes. Various Toll-like receptor ligands are capable of up regulating the NF-κB pathway, which increases radio-resistance and reduces radiation-induced apoptosis in various tissues. Several Toll-like receptor ligands have been patented and are currently under development as radiation countermeasures for acute radiation syndrome. Ongoing studies suggest that a few of these attractive agents are progressing well along the US FDA approval pathway to become radiation countermeasures. PMID:26135043

  6. Toll-like receptor 2 and type 2 diabetes.

    PubMed

    Sepehri, Zahra; Kiani, Zohre; Nasiri, Ali Akbar; Kohan, Farhad

    2016-01-01

    Innate immunity plays a crucial role in the pathogenesis of type 2 diabetes and related complications. Since the toll-like receptors (TLRs) are central to innate immunity, it appears that they are important participants in the development and pathogenesis of the disease. Previous investigations demonstrated that TLR2 homodimers and TLR2 heterodimers with TLR1 or TLR6 activate innate immunity upon recognition of damage-associated molecular patterns (DAMPs). Several DAMPs are released during type 2 diabetes, so it may be hypothesized that TLR2 is significantly involved in its progression. Here, we review recent data on the important roles and status of TLR2 in type 2 diabetes and related complications.

  7. [Association of polymorphisms in toll-like receptor genes with atopic dermatitis in the Republic of Bashkortostan].

    PubMed

    Gimalova, G F; Karunas, A S; Fedorova, Iu Iu; Gumennaia, É R; Levasheva, S V; Khismatullina, Z R; Prans, E; Koks, S; Étkina, É I; Khusnutdinova, É K

    2014-01-01

    Atopic dermatitis (AD) is a prevalent chronic inflammatory skin disease developing as a result of the interaction between genetic predisposition and environmental factors. Considerable role in allergic diseases development is played by polymorphisms of genes of pattern-recognition receptors (PRR) which are capable of recognizing conservative standard molecular structures (patterns) unique for large pathogen groups. In this study polymorphic variants of PRR genes--Toll-like receptors (TLR1, TLR2, TLR4, TLR5, TLR6, TLR9, TLR10), NOD-like receptors (NOD1, NOD2), lipopolysaccharide receptor CD14 gene, and C11orf30 and LRRC32 genes, located in 11q13.5 region, have been investigated in AD patients and control subjects from the Republic of Bashkortostan. An association of TLR1 (rs5743571 and rs5743604), TLR6 (rs5743794) and TLR10 (rs11466617) with AD was found. Our results confirm an important role of the innate immune system in the pathogenesis of AD and the significance of polymorphisms within the Toll-like receptor 2 subfamily genes in AD development.

  8. Anti-viral role of toll like receptor 4 in hepatitis B virus infection: An in vitro study.

    PubMed

    Das, Dipanwita; Sarkar, Neelakshi; Sengupta, Isha; Pal, Ananya; Saha, Debraj; Bandopadhyay, Manikankana; Das, Chandrima; Narayan, Jimmy; Singh, Shivram Prasad; Chakravarty, Runu

    2016-12-21

    Toll like receptors plays a significant anti-viral role in different infections. The aim of this study was to look into the role of toll like receptor 4 (TLR4) in hepatitis B virus (HBV) infection. Real time PCR was used to analyze the transcription of TLR4 signaling molecules, cell cycle regulators and HBV DNA viral load after triggering the HepG2.2.15 cells with TLR4 specific ligand. Nuclear factor (NF)-κB translocation on TLR4 activation was analyzed using microscopic techniques. Protein and cell cycle analysis was done using Western Blot and FACS respectively. The present study shows that TLR4 activation represses HBV infection. As a result of HBV suppression, there are several changes in host factors which include partial release in G1/S cell cycle arrest and changes in host epigenetic marks. Finally, it was observed that anti-viral action of TLR4 takes place through the NF-κB pathway. The study shows that TLR4 activation in HBV infection brings about changes in hepatocyte microenvironment and can be used for developing a promising therapeutic target in future.

  9. Repurposed transcriptomic data facilitate discovery of innate immunity toll-like receptor (TLR) Genes across Lophotrochozoa.

    PubMed

    Halanych, Kenneth M; Kocot, Kevin M

    2014-10-01

    The growing volume of genomic data from across life represents opportunities for deriving valuable biological information from data that were initially collected for another purpose. Here, we use transcriptomes collected for phylogenomic studies to search for toll-like receptor (TLR) genes in poorly sampled lophotrochozoan clades (Annelida, Mollusca, Brachiopoda, Phoronida, and Entoprocta) and one ecdysozoan clade (Priapulida). TLR genes are involved in innate immunity across animals by recognizing potential microbial infection. They have an extracellular leucine-rich repeat (LRR) domain connected to a transmembrane domain and an intracellular toll/interleukin-1 receptor (TIR) domain. Consequently, these genes are important in initiating a signaling pathway to trigger defense. We found at least one TLR ortholog in all but two taxa examined, suggesting that a broad array of lophotrochozoans may have innate immune systems similar to those observed in vertebrates and arthropods. Comparison to the SMART database confirmed the presence of both the LRR and the TIR protein motifs characteristic of TLR genes. Because we looked at only one transcriptome per species, discovery of TLR genes was limited for most taxa. However, several TRL-like genes that vary in the number and placement of LRR domains were found in phoronids. Additionally, several contigs contained LRR domains but lacked TIR domains, suggesting they were not TLRs. Many of these LRR-containing contigs had other domains (e.g., immunoglobin) and are likely involved in innate immunity. © 2014 Marine Biological Laboratory.

  10. Toll-like receptors as novel therapeutic targets for ovarian cancer.

    PubMed

    Muccioli, Maria; Sprague, Leslee; Nandigam, Harika; Pate, Michelle; Benencia, Fabian

    2012-01-01

    Ovarian cancer (OC) is an aggressive disease that affects approximately 1 in 70 women and has a poor prognosis (<50%, 5-year survival rate), in part because it is often diagnosed at a late stage. There are three main types of OC: neoplasms of surface epithelial, germ cell, or stromal origin, with surface epithelial tumors comprising about 80% of all OCs. In addition to improving diagnostics, it is necessary to develop more effective treatments for epithelial-origin OC. Here, we describe the paradoxical roles of toll-like receptor (TLR) signaling in the progression of cancer and discuss how its modulation may result in decreased tumor growth and metastasis via the attenuation of proangiogenic cytokines and potentiation of proapoptotic factors. In particular, it has been found that TLR activity can behave like a "double-edged sword", as its signaling pathways have been implicated as having both tumor-suppressive and tumor-promoting effects. With particular emphasis on OC, we discuss the need to consider the signaling details of TLRs and associated proteins in the multiple cell types present in the tumor milieu to achieve safe and effective design of TLR-based cancer therapies.

  11. Toll-Like Receptors as Novel Therapeutic Targets for Ovarian Cancer

    PubMed Central

    Muccioli, Maria; Sprague, Leslee; Nandigam, Harika; Pate, Michelle; Benencia, Fabian

    2012-01-01

    Ovarian cancer (OC) is an aggressive disease that affects approximately 1 in 70 women and has a poor prognosis (<50%, 5-year survival rate), in part because it is often diagnosed at a late stage. There are three main types of OC: neoplasms of surface epithelial, germ cell, or stromal origin, with surface epithelial tumors comprising about 80% of all OCs. In addition to improving diagnostics, it is necessary to develop more effective treatments for epithelial-origin OC. Here, we describe the paradoxical roles of toll-like receptor (TLR) signaling in the progression of cancer and discuss how its modulation may result in decreased tumor growth and metastasis via the attenuation of proangiogenic cytokines and potentiation of proapoptotic factors. In particular, it has been found that TLR activity can behave like a “double-edged sword”, as its signaling pathways have been implicated as having both tumor-suppressive and tumor-promoting effects. With particular emphasis on OC, we discuss the need to consider the signaling details of TLRs and associated proteins in the multiple cell types present in the tumor milieu to achieve safe and effective design of TLR-based cancer therapies. PMID:22530148

  12. Toll-like Receptor-mediated Down-regulation of the Deubiquitinase Cylindromatosis (CYLD) Protects Macrophages from Necroptosis in Wild-derived Mice*

    PubMed Central

    Schworer, Stephen A.; Smirnova, Irina I.; Kurbatova, Irina; Bagina, Uliana; Churova, Maria; Fowler, Trent; Roy, Ananda L.; Degterev, Alexei; Poltorak, Alexander

    2014-01-01

    Pathogen recognition by the innate immune system initiates the production of proinflammatory cytokines but can also lead to programmed host cell death. Necroptosis, a caspase-independent cell death pathway, can contribute to the host defense against pathogens or cause damage to host tissues. Receptor-interacting protein (RIP1) is a serine/threonine kinase that integrates inflammatory and necroptotic responses. To investigate the mechanisms of RIP1-mediated activation of immune cells, we established a genetic screen on the basis of RIP1-mediated necroptosis in wild-derived MOLF/EiJ mice, which diverged from classical laboratory mice over a million years ago. When compared with C57BL/6, MOLF/EiJ macrophages were resistant to RIP1-mediated necroptosis induced by Toll-like receptors. Using a forward genetic approach in a backcross panel of mice, we identified cylindromatosis (CYLD), a deubiquitinase known to act directly on RIP1 and promote necroptosis in TNF receptor signaling, as the gene conferring the trait. We demonstrate that CYLD is required for Toll-like receptor-induced necroptosis and describe a novel mechanism by which CYLD is down-regulated at the transcriptional level in MOLF/EiJ macrophages to confer protection from necroptosis. PMID:24706750

  13. Reptile Toll-like receptor 5 unveils adaptive evolution of bacterial flagellin recognition.

    PubMed

    Voogdt, Carlos G P; Bouwman, Lieneke I; Kik, Marja J L; Wagenaar, Jaap A; van Putten, Jos P M

    2016-01-07

    Toll-like receptors (TLR) are ancient innate immune receptors crucial for immune homeostasis and protection against infection. TLRs are present in mammals, birds, amphibians and fish but have not been functionally characterized in reptiles despite the central position of this animal class in vertebrate evolution. Here we report the cloning, characterization, and function of TLR5 of the reptile Anolis carolinensis (Green Anole lizard). The receptor (acTLR5) displays the typical TLR protein architecture with 22 extracellular leucine rich repeats flanked by a N- and C-terminal leucine rich repeat domain, a membrane-spanning region, and an intracellular TIR domain. The receptor is phylogenetically most similar to TLR5 of birds and most distant to fish TLR5. Transcript analysis revealed acTLR5 expression in multiple lizard tissues. Stimulation of acTLR5 with TLR ligands demonstrated unique responsiveness towards bacterial flagellin in both reptile and human cells. Comparison of acTLR5 and human TLR5 using purified flagellins revealed differential sensitivity to Pseudomonas but not Salmonella flagellin, indicating development of species-specific flagellin recognition during the divergent evolution of mammals and reptiles. Our discovery of reptile TLR5 fills the evolutionary gap regarding TLR conservation across vertebrates and provides novel insights in functional evolution of host-microbe interactions.

  14. Reptile Toll-like receptor 5 unveils adaptive evolution of bacterial flagellin recognition

    PubMed Central

    Voogdt, Carlos G. P.; Bouwman, Lieneke I.; Kik, Marja J. L.; Wagenaar, Jaap A.; van Putten, Jos P. M.

    2016-01-01

    Toll-like receptors (TLR) are ancient innate immune receptors crucial for immune homeostasis and protection against infection. TLRs are present in mammals, birds, amphibians and fish but have not been functionally characterized in reptiles despite the central position of this animal class in vertebrate evolution. Here we report the cloning, characterization, and function of TLR5 of the reptile Anolis carolinensis (Green Anole lizard). The receptor (acTLR5) displays the typical TLR protein architecture with 22 extracellular leucine rich repeats flanked by a N- and C-terminal leucine rich repeat domain, a membrane-spanning region, and an intracellular TIR domain. The receptor is phylogenetically most similar to TLR5 of birds and most distant to fish TLR5. Transcript analysis revealed acTLR5 expression in multiple lizard tissues. Stimulation of acTLR5 with TLR ligands demonstrated unique responsiveness towards bacterial flagellin in both reptile and human cells. Comparison of acTLR5 and human TLR5 using purified flagellins revealed differential sensitivity to Pseudomonas but not Salmonella flagellin, indicating development of species-specific flagellin recognition during the divergent evolution of mammals and reptiles. Our discovery of reptile TLR5 fills the evolutionary gap regarding TLR conservation across vertebrates and provides novel insights in functional evolution of host-microbe interactions. PMID:26738735

  15. Disseminated cysticercosis: clinical spectrum, Toll-like receptor-4 gene polymorphisms and role of albendazole

    PubMed Central

    Qavi, Abdul; Garg, Ravindra Kumar; Malhotra, Hardeep Singh; Jain, Amita; Kumar, Neeraj; Malhotra, Kiran Preet; Srivastava, Pradeep Kumar; Verma, Rajesh; Sharma, Praveen Kumar

    2016-01-01

    Abstract In this study, we describe clinical and imaging spectrum, and the natural course of patients with disseminated cysticercosis. How albendazole affects the course of disease has also been evaluated. We assessed the Toll-like receptor-4 gene polymorphisms, to know the reason for the apparently higher prevalence of disseminated cysticercosis in India. Sixty consecutive patients with disseminated cysticercosis were enrolled. Sixty age-and-sex-matched healthy controls were also enrolled for the purpose of genetic study. Twenty patients, who gave consent, were treated with albendazole along with corticosteroids. Forty patients did not give consent for antiparasitic therapy. Assessment for Toll-like receptor-4 gene polymorphisms (Asp299Gly and Thr399Ile genes) was done. Patients were followed for 6 months. We also performed a literature search of cases published in English language using PubMed electronic database and analyzed 56 cases thus available. There was an increased risk (6.63 fold and 4.61 fold) of disseminated cysticercosis in the presence of Asp299Gly and Thr399Ile polymorphisms in Toll-like receptor-4, respectively. The allelic frequency of Gly (11% vs. 3%, P = 0.024, odds ratio [OR] = 3.52) and Ile alleles (11% vs. 2%, P = 0.009, OR = 4.738) in disseminated cysticercosis was high. Albendazole resulted in complete disappearance of all cerebral lesions in 35% (7/20) patients and reduction in lesion load in remaining 65% (13/20) patients. No significant change in number of cysticercal lesion was noted in patients who did not receive albendazole. No major adverse reaction following antiparasitic treatment was noted. Three deaths were recorded in patients who did not receive antiparasitic treatment. Of the 56 cases reported in PubMed, 33 patients received antiparasitic treatment with follow-up data available for 31 patients. Most (24) of these patients received albendazole. A significant clinical and/or imaging improvements, on follow up, were observed in

  16. An electrochemical lipopolysaccharide sensor based on an immobilized Toll-Like Receptor-4.

    PubMed

    Mayall, R M; Renaud-Young, M; Chan, N W C; Birss, V I

    2017-01-15

    Infections affect millions of people each year and yet methods to ascertain their cause can take more than 24h to be effective. This delay between the presentation with symptoms and the ability to make an informed decision about treatment can have adverse consequences, including death in severe cases. Additionally, pathogen identification is a concern for public safety amid the growing threat of bioterrorism. Developing a detection system based on the immune system offers the advantage of broad specificity, while still remaining pertinent to human health. In this work, human Toll-Like Receptor-4 (TLR-4), a protein responsible for detecting lipopolysaccharide (LPS) of Gram-negative bacteria, was immobilized on both a large area and micro gold electrode via the tethering interaction of a modified Self-Assembled Monolayer (mSAM). In response to varying concentrations of its target, the protein-electrode combination showed a logarithmically proportional increased resistance to charge transfer from a solution-based redox probe, due to the formation of TLR-4 protein dimers. It also demonstrated excellent sensitivity to trace levels of Gram-negative bacteria, while remaining insensitive to both Gram-positive and viral challenges. Further characterization of our mSAM revealed that maintaining the appropriate receptor orientation on the electrode surface, mimicking TLR-4's role in a cellular context, was essential in producing a responsive sensor. Copyright © 2016 Elsevier B.V. All rights reserved.

  17. AP1S3 mutations are associated with pustular psoriasis and impaired Toll-like receptor 3 trafficking.

    PubMed

    Setta-Kaffetzi, Niovi; Simpson, Michael A; Navarini, Alexander A; Patel, Varsha M; Lu, Hui-Chun; Allen, Michael H; Duckworth, Michael; Bachelez, Hervé; Burden, A David; Choon, Siew-Eng; Griffiths, Christopher E M; Kirby, Brian; Kolios, Antonios; Seyger, Marieke M B; Prins, Christa; Smahi, Asma; Trembath, Richard C; Fraternali, Franca; Smith, Catherine H; Barker, Jonathan N; Capon, Francesca

    2014-05-01

    Adaptor protein complex 1 (AP-1) is an evolutionary conserved heterotetramer that promotes vesicular trafficking between the trans-Golgi network and the endosomes. The knockout of most murine AP-1 complex subunits is embryonically lethal, so the identification of human disease-associated alleles has the unique potential to deliver insights into gene function. Here, we report two founder mutations (c.11T>G [p.Phe4Cys] and c.97C>T [p.Arg33Trp]) in AP1S3, the gene encoding AP-1 complex subunit σ1C, in 15 unrelated individuals with a severe autoinflammatory skin disorder known as pustular psoriasis. Because the variants are predicted to destabilize the 3D structure of the AP-1 complex, we generated AP1S3-knockdown cell lines to investigate the consequences of AP-1 deficiency in skin keratinocytes. We found that AP1S3 silencing disrupted the endosomal translocation of the innate pattern-recognition receptor TLR-3 (Toll-like receptor 3) and resulted in a marked inhibition of downstream signaling. These findings identify pustular psoriasis as an autoinflammatory phenotype caused by defects in vesicular trafficking and demonstrate a requirement of AP-1 for Toll-like receptor homeostasis. Copyright © 2014 The American Society of Human Genetics. Published by Elsevier Inc. All rights reserved.

  18. Bench-to-bedside review: Toll-like receptors and their role in septic shock

    PubMed Central

    Opal, Steven M; Huber, Christian E

    2002-01-01

    The Toll-like receptors (TLRs) are essential transmembrane signaling receptors of the innate immune system that alert the host to the presence of a microbial invader. The recent discovery of the TLRs has rapidly expanded our knowledge of molecular events that initiate host–pathogen interactions. These functional attributes of the cellular receptors provide insights into the nature of pattern recognition receptors that activate the human antimicrobial defense systems. The fundamental significance of the TLRs in the generation of systemic inflammation and the pathogenesis of septic shock is reviewed. The potential clinical implications of therapeutic modulation of these recently characterized receptors of innate immunity are also discussed. PMID:11983038

  19. DIESEL EXHAUST ENHANCES TOLL-LIKE RECEPTOR 3 EXPRESSION AND SIGNALING IN RESPIRATORY EPITHELIAL CELLS

    EPA Science Inventory

    Our previous studies have shown that prior exposure of respiratory epithelial cells to an aqueous-trapped solution of DE (DEas) enhances the susceptibility to Influenza infections. Here we examined the effect of DEas on the toll-like receptor 3 (TLR3) pathway, which is responsib...

  20. Mannose-Binding Lectin and Toll-Like Receptor Polymorphisms and Chagas Disease in Chile

    PubMed Central

    Zulantay, Inés; Danquah, Ina; Hamann, Lutz; Schumann, Ralf R.; Apt, Werner; Mockenhaupt, Frank P.

    2012-01-01

    Mannose-binding lectin (MBL) and Toll-like receptor (TLR) polymorphisms may influence susceptibility and manifestation of Trypanosoma cruzi infection. In northern Chile, we examined 61 asymptomatic patients with chronic Chagas disease (CD), 64 patients with chronic Chagas cardiomyopathy (CCC), and 45 healthy individuals. Low-producer MBL2*B genotypes were more common in CD patients (48%) than healthy individuals (31%; adjusted odds ratio = 2.3, 95% confidence interval = 1.01–5.4, P = 0.047) but did not differ with manifestation. In contrast, the heterozygous Toll-like receptor 4 (TLR4)-deficiency genotype D299G/T399I occurred more frequently in asymptomatic (14.8%) than CCC patients (3.1%; P = 0.02). TLR1-I602S, TLR2-R753Q, TLR6-S249P, and MAL/TIRAP-S180L did not associate with CD or CCC. These findings support the complement system to be involved in defense against Trypanosoma cruzi infection and indicate that curbed TLR4 activation might be beneficial in preventing CCC. PMID:22302853

  1. Virtual Screening Approaches towards the Discovery of Toll-Like Receptor Modulators

    PubMed Central

    Pérez-Regidor, Lucía; Zarioh, Malik; Ortega, Laura; Martín-Santamaría, Sonsoles

    2016-01-01

    This review aims to summarize the latest efforts performed in the search for novel chemical entities such as Toll-like receptor (TLR) modulators by means of virtual screening techniques. This is an emergent research field with only very recent (and successful) contributions. Identification of drug-like molecules with potential therapeutic applications for the treatment of a variety of TLR-regulated diseases has attracted considerable interest due to the clinical potential. Additionally, the virtual screening databases and computational tools employed have been overviewed in a descriptive way, widening the scope for researchers interested in the field. PMID:27618029

  2. Crystal structure of Toll-like receptor adaptor MAL/TIRAP reveals the molecular basis for signal transduction and disease protection

    PubMed Central

    Valkov, Eugene; Stamp, Anna; DiMaio, Frank; Baker, David; Verstak, Brett; Roversi, Pietro; Kellie, Stuart; Sweet, Matthew J.; Mansell, Ashley; Gay, Nicholas J.; Martin, Jennifer L.; Kobe, Bostjan

    2011-01-01

    Initiation of the innate immune response requires agonist recognition by pathogen-recognition receptors such as the Toll-like receptors (TLRs). Toll/interleukin-1 receptor (TIR) domain-containing adaptors are critical in orchestrating the signal transduction pathways after TLR and interleukin-1 receptor activation. Myeloid differentiation primary response gene 88 (MyD88) adaptor-like (MAL)/TIR domain-containing adaptor protein (TIRAP) is involved in bridging MyD88 to TLR2 and TLR4 in response to bacterial infection. Genetic studies have associated a number of unique single-nucleotide polymorphisms in MAL with protection against invasive microbial infection, but a molecular understanding has been hampered by a lack of structural information. The present study describes the crystal structure of MAL TIR domain. Significant structural differences exist in the overall fold of MAL compared with other TIR domain structures: A sequence motif comprising a β-strand in other TIR domains instead corresponds to a long loop, placing the functionally important “BB loop” proline motif in a unique surface position in MAL. The structure suggests possible dimerization and MyD88-interacting interfaces, and we confirm the key interface residues by coimmunoprecipitation using site-directed mutants. Jointly, our results provide a molecular and structural basis for the role of MAL in TLR signaling and disease protection. PMID:21873236

  3. Toll-Like Receptor 2 and Mincle Cooperatively Sense Corynebacterial Cell Wall Glycolipids.

    PubMed

    Schick, Judith; Etschel, Philipp; Bailo, Rebeca; Ott, Lisa; Bhatt, Apoorva; Lepenies, Bernd; Kirschning, Carsten; Burkovski, Andreas; Lang, Roland

    2017-07-01

    Nontoxigenic Corynebacterium diphtheriae and Corynebacterium ulcerans cause invasive disease in humans and animals. Host sensing of corynebacteria is largely uncharacterized, albeit the recognition of lipoglycans by Toll-like receptor 2 (TLR2) appears to be important for macrophage activation by corynebacteria. The members of the order Corynebacterineae (e.g., mycobacteria, nocardia, and rhodococci) share a glycolipid-rich cell wall dominated by mycolic acids (termed corynomycolic acids in corynebacteria). The mycolic acid-containing cord factor of mycobacteria, trehalose dimycolate, activates the C-type lectin receptor (CLR) Mincle. Here, we show that glycolipid extracts from the cell walls of several pathogenic and nonpathogenic Corynebacterium strains directly bound to recombinant Mincle in vitro Macrophages deficient in Mincle or its adapter protein Fc receptor gamma chain (FcRγ) produced severely reduced amounts of granulocyte colony-stimulating factor (G-CSF) and of nitric oxide (NO) upon challenge with corynebacterial glycolipids. Consistently, cell wall extracts of a particular C. diphtheriae strain (DSM43989) lacking mycolic acid esters neither bound Mincle nor activated macrophages. Furthermore, TLR2 but not TLR4 was critical for sensing of cell wall extracts and whole corynebacteria. The upregulation of Mincle expression upon encountering corynebacteria required TLR2. Thus, macrophage activation by the corynebacterial cell wall relies on TLR2-driven robust Mincle expression and the cooperative action of both receptors. Copyright © 2017 American Society for Microbiology.

  4. Toll-Like Receptor 2 and Mincle Cooperatively Sense Corynebacterial Cell Wall Glycolipids

    PubMed Central

    Schick, Judith; Etschel, Philipp; Bailo, Rebeca; Ott, Lisa; Bhatt, Apoorva; Lepenies, Bernd; Kirschning, Carsten

    2017-01-01

    ABSTRACT Nontoxigenic Corynebacterium diphtheriae and Corynebacterium ulcerans cause invasive disease in humans and animals. Host sensing of corynebacteria is largely uncharacterized, albeit the recognition of lipoglycans by Toll-like receptor 2 (TLR2) appears to be important for macrophage activation by corynebacteria. The members of the order Corynebacterineae (e.g., mycobacteria, nocardia, and rhodococci) share a glycolipid-rich cell wall dominated by mycolic acids (termed corynomycolic acids in corynebacteria). The mycolic acid-containing cord factor of mycobacteria, trehalose dimycolate, activates the C-type lectin receptor (CLR) Mincle. Here, we show that glycolipid extracts from the cell walls of several pathogenic and nonpathogenic Corynebacterium strains directly bound to recombinant Mincle in vitro. Macrophages deficient in Mincle or its adapter protein Fc receptor gamma chain (FcRγ) produced severely reduced amounts of granulocyte colony-stimulating factor (G-CSF) and of nitric oxide (NO) upon challenge with corynebacterial glycolipids. Consistently, cell wall extracts of a particular C. diphtheriae strain (DSM43989) lacking mycolic acid esters neither bound Mincle nor activated macrophages. Furthermore, TLR2 but not TLR4 was critical for sensing of cell wall extracts and whole corynebacteria. The upregulation of Mincle expression upon encountering corynebacteria required TLR2. Thus, macrophage activation by the corynebacterial cell wall relies on TLR2-driven robust Mincle expression and the cooperative action of both receptors. PMID:28483856

  5. Toll-like receptor mediated activation is possibly involved in immunoregulating properties of cow's milk hydrolysates

    PubMed Central

    Kiewiet, M. B. Gea; Dekkers, Renske; Gros, Marjan; van Neerven, R. J. Joost; Groeneveld, Andre; de Vos, Paul; Faas, Marijke M.

    2017-01-01

    Immunomodulating proteins and peptides are formed during the hydrolysis of cow’s milk proteins. These proteins are potential ingredients in functional foods used for the management of a range of immune related problems, both in infants and adults. However, the mechanism behind these effects is unknown. We hypothesize that the interaction of peptides with Toll-like receptors (TLRs) can induce immune effects, since these receptors are known to sample many dietary molecules in the intestine in order to regulate immune effects. To investigate this, we compared the immune effects and TLR activation and inhibition by whey and casein hydrolysates with different hydrolysis levels. We first measured cytokine production in primary peripheral blood mononuclear cells stimulated with either whey, casein, or their hydrolysates. IL-10 and TNFα were induced by whey hydrolysates (decreasing with increasing hydrolysis level), but not by casein hydrolysates. Next, the activation of TLR 2, 3, 5 and 9 receptors were observed by intact and mildly hydrolysed whey proteins only and not by casein hydrolysates in TLR reporter cell lines. Many casein hydrolysates inhibited TLR signaling (mainly TLR 5 and 9). These results demonstrate that the effects of cow’s milk proteins on the immune system are protein type and hydrolysis dependent. TLR signaling is suggested as a possible mechanism for differences in effect. This knowledge contributes to a better understanding of the immune effects of hydrolysates and the design of infant formula, and nutrition in general, with specific immunoregulatory effects. PMID:28594834

  6. Palmitate-induced ER stress and inhibition of protein synthesis in cultured myotubes does not require Toll-like receptor 4.

    PubMed

    Perry, Ben D; Rahnert, Jill A; Xie, Yang; Zheng, Bin; Woodworth-Hobbs, Myra E; Price, S Russ

    2018-01-01

    Saturated fatty acids, such as palmitate, are elevated in metabolically dysfunctional conditions like type 2 diabetes mellitus. Palmitate has been shown to impair insulin sensitivity and suppress protein synthesis while upregulating proteolytic systems in skeletal muscle. Increased sarco/endoplasmic reticulum (ER) stress and subsequent activation of the unfolded protein response may contribute to the palmitate-induced impairment of muscle protein synthesis. In some cell types, ER stress occurs through activation of the Toll-like receptor 4 (TLR4). Given the link between ER stress and suppression of protein synthesis, we investigated whether palmitate induces markers of ER stress and protein synthesis by activating TLR4 in cultured mouse C2C12 myotubes. Myotubes were treated with vehicle, a TLR4-specific ligand (lipopolysaccharides), palmitate, or a combination of palmitate plus a TLR4-specific inhibitor (TAK-242). Inflammatory indicators of TLR4 activation (IL-6 and TNFα) and markers of ER stress were measured, and protein synthesis was assessed using puromycin incorporation. Palmitate substantially increased the levels of IL-6, TNF-α, CHOP, XBP1s, and ATF 4 mRNAs and augmented the levels of CHOP, XBP1s, phospho-PERK and phospho-eIF2α proteins. The TLR4 antagonist attenuated both acute palmitate and LPS-induced increases in IL-6 and TNFα, but did not reduce ER stress signaling with either 6 h or 24 h palmitate treatment. Similarly, treating myotubes with palmitate for 6 h caused a 43% decline in protein synthesis consistent with an increase in phospho-eIF2α, and the TLR4 antagonist did not alter these responses. These results suggest that palmitate does not induce ER stress through TLR4 in muscle, and that palmitate impairs protein synthesis in skeletal muscle in part by induction of ER stress.

  7. Energetics of Endotoxin Recognition in the Toll-Like Receptor 4 Innate Immune Response

    PubMed Central

    Paramo, Teresa; Tomasio, Susana M.; Irvine, Kate L.; Bryant, Clare E.; Bond, Peter J.

    2015-01-01

    Bacterial outer membrane lipopolysaccharide (LPS) potently stimulates the mammalian innate immune system, and can lead to sepsis, the primary cause of death from infections. LPS is sensed by Toll-like receptor 4 (TLR4) in complex with its lipid-binding coreceptor MD-2, but subtle structural variations in LPS can profoundly modulate the response. To better understand the mechanism of LPS-induced stimulation and bacterial evasion, we have calculated the binding affinity to MD-2 of agonistic and antagonistic LPS variants including lipid A, lipid IVa, and synthetic antagonist Eritoran, and provide evidence that the coreceptor is a molecular switch that undergoes ligand-induced conformational changes to appropriately activate or inhibit the receptor complex. The plasticity of the coreceptor binding cavity is shown to be essential for distinguishing between ligands, whilst similar calculations for a model bacterial LPS bilayer reveal the “membrane-like” nature of the protein cavity. The ability to predict the activity of LPS variants should facilitate the rational design of TLR4 therapeutics. PMID:26647780

  8. Trial Watch: Toll-like receptor agonists in oncological indications.

    PubMed

    Aranda, Fernando; Vacchelli, Erika; Obrist, Florine; Eggermont, Alexander; Galon, Jérôme; Sautès-Fridman, Catherine; Cremer, Isabelle; Henrik Ter Meulen, Jan; Zitvogel, Laurence; Kroemer, Guido; Galluzzi, Lorenzo

    2014-01-01

    Toll-like receptors (TLRs) are an evolutionarily conserved group of enzymatically inactive, single membrane-spanning proteins that recognize a wide panel of exogenous and endogenous danger signals. Besides constituting a crucial component of the innate immune response to bacterial and viral pathogens, TLRs appear to play a major role in anticancer immunosurveillance. In line with this notion, several natural and synthetic TLR ligands have been intensively investigated for their ability to boost tumor-targeting immune responses elicited by a variety of immunotherapeutic and chemotherapeutic interventions. Three of these agents are currently approved by the US Food and Drug Administration (FDA) or equivalent regulatory agencies for use in cancer patients: the so-called bacillus Calmette-Guérin, monophosphoryl lipid A, and imiquimod. However, the number of clinical trials testing the therapeutic potential of both FDA-approved and experimental TLR agonists in cancer patients is stably decreasing, suggesting that drug developers and oncologists are refocusing their interest on alternative immunostimulatory agents. Here, we summarize recent findings on the use of TLR agonists in cancer patients and discuss how the clinical evaluation of FDA-approved and experimental TLR ligands has evolved since the publication of our first Trial Watch dealing with this topic.

  9. Association study of Toll-like receptor 5 (TLR5) and Toll-like receptor 9 (TLR9) polymorphisms in systemic lupus erythematosus.

    PubMed

    Demirci, F Yesim K; Manzi, Susan; Ramsey-Goldman, Rosalind; Kenney, Margaret; Shaw, Penny S; Dunlop-Thomas, Charmayne M; Kao, Amy H; Rhew, Elisa Y; Bontempo, Franklin; Kammerer, Candace; Kamboh, M Ilyas

    2007-08-01

    Toll-like receptors (TLR) play an important role in both adaptive and innate immunity. Variations in TLR genes have been shown to be associated with various infectious and inflammatory diseases. We investigated the association of TLR5 (Arg392Stop, rs5744168) and TLR9 (-1237T-->C, rs5743836) single nucleotide polymorphisms (SNP) with systemic lupus erythematosus (SLE) in Caucasian American subjects. We performed a case-control association study and genotyped 409 Caucasian women with SLE and 509 Caucasian healthy female controls using TaqMan allelic discrimination (rs5744168) or polymerase chain reaction-restriction fragment length polymorphism analysis (rs5743836). None of the 2 TLR SNP showed a statistically significant association with SLE risk in our cohort. Our results do not indicate a major influence of these putative functional TLR SNP on the susceptibility to (or protection from) SLE.

  10. Control of B-cell responses by Toll-like receptors

    NASA Astrophysics Data System (ADS)

    Pasare, Chandrashekhar; Medzhitov, Ruslan

    2005-11-01

    Toll-like receptors (TLRs) detect microbial infection and have an essential role in the induction of immune responses. TLRs can directly induce innate host defence responses, but the mechanisms of TLR-mediated control of adaptive immunity are not fully understood. Although TLR-induced dendritic cell maturation is required for activation of T-helper (TH) cells, the role of TLRs in B-cell activation and antibody production in vivo is not yet known. Here we show that activation and differentiation of TH cells is not sufficient for the induction of T-dependent B-cell responses. We find that, in addition to CD4+ T-cell help, generation of T-dependent antigen-specific antibody responses requires activation of TLRs in B cells.

  11. The evolution of vertebrate Toll-like receptors

    USGS Publications Warehouse

    Roach, J.C.; Glusman, G.; Rowen, L.; Kaur, A.; Purcell, M.K.; Smith, K.D.; Hood, L.E.; Aderem, A.

    2005-01-01

    The complete sequences of Takifugu Toll-like receptor (TLR) loci and gene predictions from many draft genomes enable comprehensive molecular phylogenetic analysis. Strong selective pressure for recognition of and response to pathogen-associated molecular patterns has maintained a largely unchanging TLR recognition in all vertebrates. There are six major families of vertebrate TLRs. This repertoire is distinct from that of invertebrates. TLRs within a family recognize a general class of pathogen-associated molecular patterns. Most vertebrates have exactly one gene ortholog for each TLR family. The family including TLR1 has more species-specific adaptations than other families. A major family including TLR11 is represented in humans only by a pseudogene. Coincidental evolution plays a minor role in TLR evolution. The sequencing phase of this study produced finished genomic sequences for the 12 Takifugu rubripes TLRs. In addition, we have produced > 70 gene models, including sequences from the opossum, chicken, frog, dog, sea urchin, and sea squirt. ?? 2005 by The National Academy of Sciences of the USA.

  12. Transgenic cloned sheep overexpressing ovine toll-like receptor 4.

    PubMed

    Deng, Shoulong; Li, Guiguan; Zhang, Jinlong; Zhang, Xiaosheng; Cui, Maosheng; Guo, Yong; Liu, Guoshi; Li, Guangpeng; Feng, Jianzhong; Lian, Zhengxing

    2013-07-01

    An ovine fetal fibroblast cell line highly expressing TLR4 was established by inserting TLR4 into a reconstructive p3S-LoxP plasmid. Transgenic sheep overexpressing TLR4 were produced by transferring TLR4-transfected fetal fibroblasts into metaphase (M)II-stage enucleated oocytes (using SCNT). Because reconstructed embryos derived from MII-stage enucleated oocytes matured in vivo using a delayed-activated method had a higher pregnancy rate (18.52%) than that from MII-stage enucleated oocytes matured in vitro, the former procedure was used. Nine TLR4-transgenic live births were confirmed using polymerase chain reaction and Southern blot analysis. Increased expression of TLR4 at mRNA and protein levels in ear tissues of transgenic lambs were verified using reverse transcription polymerase chain reaction and immunohistochemistry, respectively. More toll-like receptor 4 protein was expressed by peripheral blood monocytes and/or macrophages collected from 3-month-old TLR4-transgenic than nontransgenic lambs at 0, 1, and 4 hours after lipopolysaccharide stimulation. Furthermore, interferon-γ and tumor necrosis factor α secreted by monocytes and/or macrophages of TLR4-transgenic lambs were significantly higher at 1 hour. Therefore, lipopolysaccharide-induced inflammatory responses from monocytes and/or macrophages occurred sooner in TLR4-transgenic lambs, consistent with an enhanced host immune response. In conclusion, transgenic sheep overexpressing TLR4 are a primary model to investigate the role of transgenic animals in disease resistance and have potential for breeding sheep with disease resistance. Copyright © 2013 Elsevier Inc. All rights reserved.

  13. Modeling the interactions of bacteria and Toll-like receptor-mediated inflammation in necrotizing enterocolitis

    PubMed Central

    Arciero, Julia; Ermentrout, G. Bard; Siggers, Richard; Afrazi, Amin; Hackam, David; Vodovotz, Yoram; Rubin, Jonathan

    2016-01-01

    Necrotizing enterocolitis (NEC) is a severe disease of the gastrointestinal tract in premature infants, characterized by a disrupted intestinal epithelium and an exaggerated pro-inflammatory response. Since the activation of Toll-like receptor-4 (TLR4) blocks cell migration and proliferation and contributes to an uncontrolled inflammatory response within the intestine, this receptor has been identified as a key contributor to the development of NEC. Toll-like receptor-9 (TLR9) has been shown to sense bacterial genome components (CpG DNA) and to play an anti-inflammatory role in NEC. We present in vitro results demonstrating direct inhibition of TLR4 activation by CpG DNA, and we develop a mathematical model of bacteria–immune interactions within the intestine to investigate how such inhibition of TLR4 signaling might alter inflammation, associated bacterial invasion of tissue, and resulting outcomes. The model predicts that TLR9 can inhibit both the beneficial and detrimental effects of TLR4, and thus a proper balance of action by these two receptors is needed to promote intestinal health. The model results are also used to explore three interventions that could potentially prevent the development of NEC: reducing bacteria in the mucus layer, administering probiotic treatment, and blocking TLR4 activation. While the model shows that these interventions would be successful in most cases, the model is also used to identify situations in which the proposed treatments might be harmful. PMID:23238281

  14. Computational Insight Into the Structural Organization of Full-Length Toll-Like Receptor 4 Dimer in a Model Phospholipid Bilayer

    PubMed Central

    Patra, Mahesh Chandra; Kwon, Hyuk-Kwon; Batool, Maria; Choi, Sangdun

    2018-01-01

    Toll-like receptors (TLRs) are a unique category of pattern recognition receptors that recognize distinct pathogenic components, often utilizing the same set of downstream adaptors. Specific molecular features of extracellular, transmembrane (TM), and cytoplasmic domains of TLRs are crucial for coordinating the complex, innate immune signaling pathway. Here, we constructed a full-length structural model of TLR4—a widely studied member of the interleukin-1 receptor/TLR superfamily—using homology modeling, protein–protein docking, and molecular dynamics simulations to understand the differential domain organization of TLR4 in a membrane-aqueous environment. Results showed that each functional domain of the membrane-bound TLR4 displayed several structural transitions that are biophysically essential for plasma membrane integration. Specifically, the extracellular and cytoplasmic domains were partially immersed in the upper and lower leaflets of the membrane bilayer. Meanwhile, TM domains tilted considerably to overcome the hydrophobic mismatch with the bilayer core. Our analysis indicates an alternate dimerization or a potential oligomerization interface of TLR4-TM. Moreover, the helical properties of an isolated TM dimer partly agree with that of the full-length receptor. Furthermore, membrane-absorbed or solvent-exposed surfaces of the toll/interleukin-1 receptor domain are consistent with previous X-ray crystallography and biochemical studies. Collectively, we provided a complete structural model of membrane-bound TLR4 that strengthens our current understanding of the complex mechanism of receptor activation and adaptor recruitment in the innate immune signaling pathway. PMID:29593733

  15. Toll-like receptors participate in Naegleria fowleri recognition.

    PubMed

    Martínez-Castillo, Moisés; Santos-Argumedo, Leopoldo; Galván-Moroyoqui, José Manuel; Serrano-Luna, Jesús; Shibayama, Mineko

    2018-01-01

    Naegleria fowleri is a protozoan that invades the central nervous system and causes primary amoebic meningoencephalitis. It has been reported that N. fowleri induces an important inflammatory response during the infection. In the present study, we evaluated the roles of Toll-like receptors in the recognition of N. fowleri trophozoites by human mucoepithelial cells, analyzing the expression and production of innate immune response mediators. After amoebic interactions with NCI-H292 cells, the expression and production levels of IL-8, TNF-α, IL-1β, and human beta defensin-2 were evaluated by RT-PCR, ELISA, immunofluorescence, and dot blot assays, respectively. To determine whether the canonical signaling pathways were engaged, we used different inhibitors, namely, IMG-2005 for MyD88 and BAY 11-7085 for the nuclear factor NFkB. Our results showed that the expression and production of the pro-inflammatory cytokines and beta defensin-2 were induced by N. fowleri mainly through the canonical TLR4 pathway in a time-dependent manner.

  16. Toll-Like Receptor 4 Deficiency Impairs Motor Coordination

    PubMed Central

    Zhu, Jian-Wei; Li, Yi-Fei; Wang, Zhao-Tao; Jia, Wei-Qiang; Xu, Ru-Xiang

    2016-01-01

    The cerebellum plays an essential role in balance and motor coordination. Purkinje cells (PCs) are the sole output neurons of the cerebellar cortex and are critical for the execution of its functions, including motor coordination. Toll-like receptor (TLR) 4 is involved in the innate immune response and is abundantly expressed in the central nervous system; however, little is known about its role in cerebellum-related motor functions. To address this question, we evaluated motor behavior in TLR4 deficient mice. We found that TLR4−∕− mice showed impaired motor coordination. Morphological analyses revealed that TLR4 deficiency was associated with a reduction in the thickness of the molecular layer of the cerebellum. TLR4 was highly expressed in PCs but not in Bergmann glia or cerebellar granule cells; however, loss of TLR4 decreased the number of PCs. These findings suggest a novel role for TLR4 in cerebellum-related motor coordination through maintenance of the PC population. PMID:26909014

  17. Molecular cloning, characterization, and functional analysis of pigeon (Columba livia) Toll-like receptor 5.

    PubMed

    Xiong, Dan; Song, Li; Pan, Zhiming; Jiao, Xinan

    2018-06-26

    Toll-like receptors (TLRs) are pattern recognition receptors that are vital for the recognition of pathogen-associated molecular patterns. TLR5 is responsible for the recognition of bacterial flagellin to induce the NF-κB activation and innate immune responses. In this study, we cloned and identified the TLR5 gene from the King pigeon (Columba livia) designated as PiTLR5. Full-length PiTLR5 cDNA (2583 bp) encoded an 860-amino acid protein containing a signal peptide sequence, 10 leucine-rich repeat domains, a leucine-rich repeat C-terminal domain, a transmembrane domain, and an intracellular Toll-interleukin-1 receptor domain. Pigeon TLR5 mRNA expression was quantified by performing quantitative real-time PCR (qRT-PCR), which showed that PiTLR5 was broadly expressed in all examined tissues, with the highest expression in the liver, peripheral blood mononuclear cells, and spleen. PiTLR5-mediated innate immune responses were measured by determining its effects on NF-κB activation and cytokine expression. The results showed that HEK293T cells transfected with PiTLR5 robustly activated the NF-κB response to flagellin, but not other TLR stimuli, and induced significant upregulation of IL-1β, IL-8, TNF-α, and IFN-γ, indicating that PiTLR5 is a functional TLR5 homolog. Additionally, following flagellin stimulation of pigeon splenic lymphocytes, the levels of TLR5, NF-κB, IL-6, IL-8, CCL5, and IFN-γ mRNA, assessed using qRT-PCR, were significantly upregulated. Besides, TLR5 knockdown resulted in the significantly downregulated expression of NF-κB and related cytokines/chemokines. Triggering pigeon TLR5 contributes to significant upregulation of inflammatory cytokines and chemokines, suggesting that pigeon TLR5 plays an important role in the innate immune responses.

  18. Introgression of Neandertal- and Denisovan-like Haplotypes Contributes to Adaptive Variation in Human Toll-like Receptors

    PubMed Central

    Dannemann, Michael; Andrés, Aida M.; Kelso, Janet

    2016-01-01

    Pathogens and the diseases they cause have been among the most important selective forces experienced by humans during their evolutionary history. Although adaptive alleles generally arise by mutation, introgression can also be a valuable source of beneficial alleles. Archaic humans, who lived in Europe and Western Asia for more than 200,000 years, were probably well adapted to this environment and its local pathogens. It is therefore conceivable that modern humans entering Europe and Western Asia who admixed with them obtained a substantial immune advantage from the introgression of archaic alleles. Here we document a cluster of three Toll-like receptors (TLR6-TLR1-TLR10) in modern humans that carries three distinct archaic haplotypes, indicating repeated introgression from archaic humans. Two of these haplotypes are most similar to the Neandertal genome, and the third haplotype is most similar to the Denisovan genome. The Toll-like receptors are key components of innate immunity and provide an important first line of immune defense against bacteria, fungi, and parasites. The unusually high allele frequencies and unexpected levels of population differentiation indicate that there has been local positive selection on multiple haplotypes at this locus. We show that the introgressed alleles have clear functional effects in modern humans; archaic-like alleles underlie differences in the expression of the TLR genes and are associated with reduced microbial resistance and increased allergic disease in large cohorts. This provides strong evidence for recurrent adaptive introgression at the TLR6-TLR1-TLR10 locus, resulting in differences in disease phenotypes in modern humans. PMID:26748514

  19. Crosstalk Between Adrenergic and Toll-Like Receptors in Human Mesenchymal Stem Cells and Keratinocytes: A Recipe for Impaired Wound Healing

    PubMed Central

    Ramirez, Sandra R.; La, Thi Dinh; Gorouhi, Farzam; Nguyen, Chuong; Lin, Benjamin R.; Mashburn, Chelcy; Stewart, Heather; Peavy, Thomas R.; Nolta, Jan A.

    2014-01-01

    Previous studies demonstrate that skin wounds generate epinephrine (EPI) that can activate local adrenergic receptors (ARs), impairing healing. Bacterially derived activators of Toll-like receptors (TLRs) within the wound initiate inflammatory responses and can also impair healing. In this study, we examined the hypothesis that these two pathways crosstalk to one another, using EPI and macrophage-activating lipopeptide-2 (MALP2) to activate ARs and TLR2, respectively, in human bone marrow-derived mesenchymal stem cells (BM-MSCs) and neonatal keratinocytes (NHKs). BM-MSCs exposed to EPI significantly (p < .05) increased TLR2 message (sevenfold BM-MSCs), TLR2 protein (twofold), and myeloid differentiation factor 88 (MyD88) (fourfold). Conversely, activation of TLR2 by MALP2 in these cells increased β2-AR message (twofold in BM-MSCs, 2.7-fold in NHKs), β2-AR protein (2.5-fold), phosphorylation of β-AR-activated kinase (p-BARK, twofold), and induced release of EPI from both cell types (twofold). Treating cells with EPI and MALP2 together, as would be encountered in a wound, increased β2-AR and p-BARK protein expression (sixfold), impaired cell migration (BM-MSCs- 21%↓ and NHKs- 60%↓, p < .002), and resulted in a 10-fold (BM-MSCs) and 51-fold (NHKs) increase in release of IL-6 (p < .001) responses that were remarkably reduced by pretreatment with β2-AR antagonists. In vivo, EPI-stressed animals exhibited impaired healing, with elevated levels of TLR2, MyD88, and IL-6 in the wounds (p < .05) relative to nonstressed controls. Thus, our data describe a recipe for decreasing cell migration and exacerbating inflammation via novel crosstalk between the adrenergic and Toll-like receptor pathways in BM-MSCs and NHKs. PMID:24760207

  20. Toll-like receptor cascade and gene polymorphism in host-pathogen interaction in Lyme disease.

    PubMed

    Rahman, Shusmita; Shering, Maria; Ogden, Nicholas H; Lindsay, Robbin; Badawi, Alaa

    2016-01-01

    Lyme disease (LD) risk occurs in North America and Europe where the tick vectors of the causal agent Borrelia burgdorferi sensu lato are found. It is associated with local and systemic manifestations, and has persistent posttreatment health complications in some individuals. The innate immune system likely plays a critical role in both host defense against B. burgdorferi and disease severity. Recognition of B. burgdorferi, activation of the innate immune system, production of proinflammatory cytokines, and modulation of the host adaptive responses are all initiated by Toll-like receptors (TLRs). A number of Borrelia outer-surface proteins (eg, OspA and OspB) are recognized by TLRs. Specifically, TLR1 and TLR2 were identified as the receptors most relevant to LD. Several functional single-nucleotide polymorphisms have been identified in TLR genes, and are associated with varying cytokines types and synthesis levels, altered pathogen recognition, and disruption of the downstream signaling cascade. These single-nucleotide polymorphism-related functional alterations are postulated to be linked to disease development and posttreatment persistent illness. Elucidating the role of TLRs in LD may facilitate a better understanding of disease pathogenesis and can provide an insight into novel therapeutic targets during active disease or postinfection and posttreatment stages.

  1. Toll-like receptor cascade and gene polymorphism in host–pathogen interaction in Lyme disease

    PubMed Central

    Rahman, Shusmita; Shering, Maria; Ogden, Nicholas H; Lindsay, Robbin; Badawi, Alaa

    2016-01-01

    Lyme disease (LD) risk occurs in North America and Europe where the tick vectors of the causal agent Borrelia burgdorferi sensu lato are found. It is associated with local and systemic manifestations, and has persistent posttreatment health complications in some individuals. The innate immune system likely plays a critical role in both host defense against B. burgdorferi and disease severity. Recognition of B. burgdorferi, activation of the innate immune system, production of proinflammatory cytokines, and modulation of the host adaptive responses are all initiated by Toll-like receptors (TLRs). A number of Borrelia outer-surface proteins (eg, OspA and OspB) are recognized by TLRs. Specifically, TLR1 and TLR2 were identified as the receptors most relevant to LD. Several functional single-nucleotide polymorphisms have been identified in TLR genes, and are associated with varying cytokines types and synthesis levels, altered pathogen recognition, and disruption of the downstream signaling cascade. These single-nucleotide polymorphism-related functional alterations are postulated to be linked to disease development and posttreatment persistent illness. Elucidating the role of TLRs in LD may facilitate a better understanding of disease pathogenesis and can provide an insight into novel therapeutic targets during active disease or postinfection and posttreatment stages. PMID:27330321

  2. Inhibition of homodimerization of toll-like receptor 4 by 6-shogaol.

    PubMed

    Ahn, Sang-Il; Lee, Jun-Kyung; Youn, Hyung-Sun

    2009-02-28

    Toll-like receptors (TLRs) play a critical role in sensing microbial components and inducing innate immune and inflammatory responses by recognizing invading microbial pathogens. Lipopolysaccharide-induced dimerization of TLR4 is required for the activation of downstream signaling pathways including nuclear factor-kappa B (NF-kappaB). Therefore, TLR4 dimerization may be an early regulatory event in activating ligand-induced signaling pathways and induction of subsequent immune responses. Here, we report biochemical evidence that 6-shogaol, the most bioactive component of ginger, inhibits lipopolysaccharide-induced dimerization of TLR4 resulting in the inhibition of NF-kappaB activation and the expression of cyclooxygenase-2. Furthermore, we demonstrate that 6-shogaol can directly inhibit TLR-mediated signaling pathways at the receptor level. These results suggest that 6-shogaol can modulate TLR-mediated inflammatory responses, which may influence the risk of chronic inflammatory diseases.

  3. Toll-like receptor 2 enhances ZO-1-associated intestinal epithelial barrier integrity via protein kinase C.

    PubMed

    Cario, Elke; Gerken, Guido; Podolsky, Daniel K

    2004-07-01

    Protein kinase C (PKC) has been implicated in regulation of intestinal epithelial integrity in response to lumenal bacteria. Intestinal epithelial cells (IECs) constitutively express Toll-like receptor (TLR)2, which contains multiple potential PKC binding sites. The aim of this study was to determine whether TLR2 may activate PKC in response to specific ligands, thus potentially modulating barrier function in IECs. TLR2 agonist (synthetic bacterial lipopeptide Pam(3)CysSK4, peptidoglycan)-induced activation of PKC-related signaling cascades were assessed by immunoprecipitation, Western blotting, immunofluorescence, and kinase assays-combined with functional transfection studies in the human model IEC lines HT-29 and Caco-2. Transepithelial electrical resistance characterized intestinal epithelial barrier function. Stimulation with TLR2 ligands led to activation (phosphorylation, enzymatic activity, translocation) of specific PKC isoforms (PKCalpha and PKCdelta). Phosphorylation of PKC by TLR2 ligands was blocked specifically by transfection with a TLR2 deletion mutant. Ligand-induced activation of TLR2 greatly enhanced transepithelial resistance in IECs, which was prevented by pretreatment with PKC-selective antagonists. This effect correlated with apical tightening and sealing of tight junction (TJ)-associated ZO-1, which was mediated via PKC in response to TLR2 ligands, whereas morphologic changes of occludin, claudin-1, or actin cytoskeleton were not evident. Downstream the endogenous PKC substrate myristoylated alanine-rich C kinase substrate (MARCKS), but not transcriptional factor activator protein-1 (AP-1), was activated significantly on stimulation. The present study provides evidence that PKC is an essential component of the TLR2 signaling pathway with the physiologic consequence of directly enhancing intestinal epithelial integrity through translocation of ZO-1 on activation.

  4. GENES, IN ADDITION TO TOLL-LIKE RECEPTOR 2, PLAY A ROLE IN ANTIBACTERIAL DEFENSE TO STREPTOCOCCAL PNEUMONIA

    EPA Science Inventory

    Streptococcus infection in human populations continues to be a major cause of morbidity and mortality. To evaluate the effect of genetic background and toll-like receptor 2 (TLR2) on antibacterial defense to streptococcal infection, eight genetically diverse strains of mic...

  5. Toll-like Receptor 4-mediated Endoplasmic Reticulum Stress in Intestinal Crypts Induces Necrotizing Enterocolitis*

    PubMed Central

    Afrazi, Amin; Branca, Maria F.; Sodhi, Chhinder P.; Good, Misty; Yamaguchi, Yukihiro; Egan, Charlotte E.; Lu, Peng; Jia, Hongpeng; Shaffiey, Shahab; Lin, Joyce; Ma, Congrong; Vincent, Garrett; Prindle, Thomas; Weyandt, Samantha; Neal, Matthew D.; Ozolek, John A.; Wiersch, John; Tschurtschenthaler, Markus; Shiota, Chiyo; Gittes, George K.; Billiar, Timothy R.; Mollen, Kevin; Kaser, Arthur; Blumberg, Richard; Hackam, David J.

    2014-01-01

    The cellular cues that regulate the apoptosis of intestinal stem cells (ISCs) remain incompletely understood, yet may play a role in diseases characterized by ISC loss including necrotizing enterocolitis (NEC). Toll-like receptor-4 (TLR4) was recently found to be expressed on ISCs, where its activation leads to ISC apoptosis through mechanisms that remain incompletely explained. We now hypothesize that TLR4 induces endoplasmic reticulum (ER) stress within ISCs, leading to their apoptosis in NEC pathogenesis, and that high ER stress within the premature intestine predisposes to NEC development. Using transgenic mice and cultured enteroids, we now demonstrate that TLR4 induces ER stress within Lgr5 (leucine-rich repeat-containing G-protein-coupled receptor 5)-positive ISCs, resulting in crypt apoptosis. TLR4 signaling within crypts was required, because crypt ER stress and apoptosis occurred in TLR4ΔIEC-OVER mice expressing TLR4 only within intestinal crypts and epithelium, but not TLR4ΔIEC mice lacking intestinal TLR4. TLR4-mediated ER stress and apoptosis of ISCs required PERK (protein kinase-related PKR-like ER kinase), CHOP (C/EBP homologous protein), and MyD88 (myeloid differentiation primary response gene 88), but not ATF6 (activating transcription factor 6) or XBP1 (X-box-binding protein 1). Human and mouse NEC showed high crypt ER stress and apoptosis, whereas genetic inhibition of PERK or CHOP attenuated ER stress, crypt apoptosis, and NEC severity. Strikingly, using intragastric delivery into fetal mouse intestine, prevention of ER stress reduced TLR4-mediated ISC apoptosis and mucosal disruption. These findings identify a novel link between TLR4-induced ER stress and ISC apoptosis in NEC pathogenesis and suggest that increased ER stress within the premature bowel predisposes to NEC development. PMID:24519940

  6. Toll-like receptor 4-mediated endoplasmic reticulum stress in intestinal crypts induces necrotizing enterocolitis.

    PubMed

    Afrazi, Amin; Branca, Maria F; Sodhi, Chhinder P; Good, Misty; Yamaguchi, Yukihiro; Egan, Charlotte E; Lu, Peng; Jia, Hongpeng; Shaffiey, Shahab; Lin, Joyce; Ma, Congrong; Vincent, Garrett; Prindle, Thomas; Weyandt, Samantha; Neal, Matthew D; Ozolek, John A; Wiersch, John; Tschurtschenthaler, Markus; Shiota, Chiyo; Gittes, George K; Billiar, Timothy R; Mollen, Kevin; Kaser, Arthur; Blumberg, Richard; Hackam, David J

    2014-04-04

    The cellular cues that regulate the apoptosis of intestinal stem cells (ISCs) remain incompletely understood, yet may play a role in diseases characterized by ISC loss including necrotizing enterocolitis (NEC). Toll-like receptor-4 (TLR4) was recently found to be expressed on ISCs, where its activation leads to ISC apoptosis through mechanisms that remain incompletely explained. We now hypothesize that TLR4 induces endoplasmic reticulum (ER) stress within ISCs, leading to their apoptosis in NEC pathogenesis, and that high ER stress within the premature intestine predisposes to NEC development. Using transgenic mice and cultured enteroids, we now demonstrate that TLR4 induces ER stress within Lgr5 (leucine-rich repeat-containing G-protein-coupled receptor 5)-positive ISCs, resulting in crypt apoptosis. TLR4 signaling within crypts was required, because crypt ER stress and apoptosis occurred in TLR4(ΔIEC-OVER) mice expressing TLR4 only within intestinal crypts and epithelium, but not TLR4(ΔIEC) mice lacking intestinal TLR4. TLR4-mediated ER stress and apoptosis of ISCs required PERK (protein kinase-related PKR-like ER kinase), CHOP (C/EBP homologous protein), and MyD88 (myeloid differentiation primary response gene 88), but not ATF6 (activating transcription factor 6) or XBP1 (X-box-binding protein 1). Human and mouse NEC showed high crypt ER stress and apoptosis, whereas genetic inhibition of PERK or CHOP attenuated ER stress, crypt apoptosis, and NEC severity. Strikingly, using intragastric delivery into fetal mouse intestine, prevention of ER stress reduced TLR4-mediated ISC apoptosis and mucosal disruption. These findings identify a novel link between TLR4-induced ER stress and ISC apoptosis in NEC pathogenesis and suggest that increased ER stress within the premature bowel predisposes to NEC development.

  7. Synthesis and Characterization of PEGylated Toll Like Receptor 7 Ligands

    PubMed Central

    Chan, Michael; Hayashi, Tomoko; Mathewson, Richard D.; Yao, Shiyin; Gray, Christine; Tawatao, Rommel; Kalenian, Kevin; Zhang, Yanmei; Hayashi, Yuki; Lao, Fitzgerald S.; Cottam, Howard B.; Carson, Dennis A.

    2011-01-01

    Toll like receptor 7 (TLR7) is located in the endosomal compartment of immune cells. Signaling through TLR7, mediated by the adaptor protein MyD88, stimulates the innate immune system and shapes adaptive immune responses. Previously, we characterized TLR7 ligands conjugated to protein, lipid or polyethylene glycol (PEG). Among the TLR7 ligand conjugates, the addition of PEG chains reduced the agonistic potency. PEGs are safe in humans and widely used for improvement of pharmacokinetics in existing biologics and some low molecular weight compounds. PEGylation could be a feasible method to alter the pharmacokinetics and pharmacodynamics of TLR7 ligands. In this study, we systematically studied the influence of PEG chain length on the in vitro and in vivo properties of potent TLR7 ligands. PEGylation increased solubility of the TLR7 ligands and modulated protein binding. Adding a 6–10 length PEG to the TLR7 ligand reduced its potency toward induction of interleukin (IL)-6 by murine macrophages in vitro and IL-6 and tumor necrosis factor (TNF) in vivo. However, PEGylation with 18 or longer chain restored, and even enhanced, the agonistic activity of the drug. In human peripheral blood mononuclear cells, similar effects of PEGylation were observed for secretion of proinflammatory cytokines, IL-6, IL-12, TNF-α, IL-1β and type 1 interferon, as well for B cell proliferation. In summary, these studies demonstrate that conjugation of PEG chains to a synthetic TLR ligand can impact its potency for cytokine induction depending on the size of the PEG moiety. Thus, PEGylation may be a feasible approach to regulate the pharmacological properties of TLR7 ligands. PMID:21338093

  8. Toll-like receptors in inflammatory bowel diseases: a decade later.

    PubMed

    Cario, Elke

    2010-09-01

    Differential alteration of Toll-like receptor (TLR) expression in inflammatory bowel disease (IBD) was first described 10 years ago. Since then, studies from many groups have led to the current concept that TLRs represent key mediators of innate host defense in the intestine, involved in maintaining mucosal as well as commensal homeostasis. Recent findings in diverse murine models of colitis have helped to reveal the mechanistic importance of TLR dysfunction in IBD pathogenesis. It has become evident that environment, genetics, and host immunity form a multidimensional and highly interactive regulatory triad that controls TLR function in the intestinal mucosa. Imbalanced relationships within this triad may promote aberrant TLR signaling, critically contributing to acute and chronic intestinal inflammatory processes in IBD colitis and associated cancer.

  9. Expression and activation of toll-like receptor 3 and toll-like receptor 4 on human corneal epithelial and conjunctival fibroblasts.

    PubMed

    Erdinest, Nir; Aviel, Gal; Moallem, Eli; Anteby, Irene; Yahalom, Claudia; Mechoulam, Hadas; Ovadia, Haim; Solomon, Abraham

    2014-02-04

    Toll-like receptors (TLRs) are recognized as important contributors to the initiation and modulation of the inflammatory response in the eye. This study investigated the precise expression patterns and functionality of TLRs in human corneal epithelial cells (HCE) and in conjunctival fibroblasts (HCF). The cell surface expression of TLRs 2-4, TLR7 and TLR9 in HCE and HCF was examined by flow cytometry with or without stimulation with lipopolysaccharide (LPS) or polyinosinic:polycytidylic acid (poly I:C). The mRNA expression of the TLRs was determined by real-time PCR. The protein content levels of interleukin (IL)-6, IL-8, IL-1β and tumor necrosis factor-α (TNF-α) were measured in HCE and HCF using multiplex fluorescent bead immunoassay (FBI). The surface expression of TLR3 and TLR4 was detected on both HCE and HCF. Following incubation with LPS, the percentage of HCE cells staining for TLR4 decreased from 10.18% to 0.62% (P < 0.001). Incubation with poly I:C lowered the percentage of HCE cells positive for TLR3 from 10.44% to 2.84% (P < 0.001). The mRNA expression of TLRs2, 4, 7 and 9 was detected in HCE only. Activation of HCE with LPS complex elicited protein secretion up to 4.51 ± 0.85-fold higher levels of IL-6 (P < 0.05), 2.5 ± 0.36-fold IL-8 (P > 0.05), 4.35 ± 1.12-fold IL-1β (P > 0.05) and 29.35 ± 2.3-fold TNFα (P < 0.05) compared to cells incubated in medium. HCF and HCE both express TLRs that respond to specific ligands by increasing cytokine expression. Following activation, the surface expression of TLR3 and TLR4 on HCE is decreased, thus creating a negative feedback loop, mitigating the effect of TLR activation.

  10. Expression and activation of toll-like receptor 3 and toll-like receptor 4 on human corneal epithelial and conjunctival fibroblasts

    PubMed Central

    2014-01-01

    Background Toll-like receptors (TLRs) are recognized as important contributors to the initiation and modulation of the inflammatory response in the eye. This study investigated the precise expression patterns and functionality of TLRs in human corneal epithelial cells (HCE) and in conjunctival fibroblasts (HCF). Methods The cell surface expression of TLRs 2-4, TLR7 and TLR9 in HCE and HCF was examined by flow cytometry with or without stimulation with lipopolysaccharide (LPS) or polyinosinic:polycytidylic acid (poly I:C). The mRNA expression of the TLRs was determined by real-time PCR. The protein content levels of interleukin (IL)-6, IL-8, IL-1β and tumor necrosis factor-α (TNF-α) were measured in HCE and HCF using multiplex fluorescent bead immunoassay (FBI). Results The surface expression of TLR3 and TLR4 was detected on both HCE and HCF. Following incubation with LPS, the percentage of HCE cells staining for TLR4 decreased from 10.18% to 0.62% (P < 0.001). Incubation with poly I:C lowered the percentage of HCE cells positive for TLR3 from 10.44% to 2.84% (P < 0.001). The mRNA expression of TLRs2, 4, 7 and 9 was detected in HCE only. Activation of HCE with LPS complex elicited protein secretion up to 4.51 ± 0.85-fold higher levels of IL-6 (P < 0.05), 2.5 ± 0.36-fold IL-8 (P > 0.05), 4.35 ± 1.12-fold IL-1β (P > 0.05) and 29.35 ± 2.3-fold TNFα (P < 0.05) compared to cells incubated in medium. Conclusions HCF and HCE both express TLRs that respond to specific ligands by increasing cytokine expression. Following activation, the surface expression of TLR3 and TLR4 on HCE is decreased, thus creating a negative feedback loop, mitigating the effect of TLR activation. PMID:24491080

  11. Expression analysis of Toll like receptors and interleukins in Tharparkar cattle during acclimation to heat stress exposure.

    PubMed

    Bharati, Jaya; Dangi, S S; Mishra, S R; Chouhan, V S; Verma, V; Shankar, O; Bharti, M K; Paul, A; Mahato, Dilip K; Rajesh, G; Singh, G; Maurya, V P; Bag, S; Kumar, Puneet; Sarkar, M

    2017-04-01

    Six male Tharparkar cattle of 2-3 years old were selected for the study. After 15 days acclimation at thermo neutral zone (TNZ) in psychrometric chamber, animals were exposed at 42°C for 6h up to 23 days followed by 12 days of recovery period. Blood samples were collected during control period at TNZ (day 1, 5 and 12), after heat stress exposure (day 1-10, Short Term Heat Stress Acclimation - STHSA; day 15-23, Long Term Heat Stress Acclimation - LTHSA) and recovery period (day 7 and 12) and peripheral blood mononuclear cells (PBMCs) were isolated for RNA and protein extraction. Serum cortisol concentration was assessed by RIA. The mRNA and protein expression in PBMCs were determined by qPCR and western blot respectively. Samples at TNZ were taken as control. Serum cortisol concentration was increased (P<0.05) during STHSA and gradually declined during LTHSA. Toll like receptor 2 (TLR 2) expression was up regulated (P<0.05) during STHSA and declined to basal level during LTHSA and recovery phase. However, toll like receptor 4 (TLR 4) expression was up regulated (P<0.05) during STHSA and LTHSA while declined in recovery phase. Interleukin 2 (IL2) and interleukin 6 (IL 6) were up regulated (P<0.05) during STHSA and reduced to basal level during LTHSA. PBMCs culture study was conducted to study transcriptional abundance of TLR2/4 and IL2/6 at different temperature-time combinations. The present findings indicate that TLR 2/4 and IL 2/6 could possibly play a vital role in thermo tolerance in Tharparkar cattle during short term and long term heat stress exposure. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. Klotho preservation by Rhein promotes toll-like receptor 4 proteolysis and attenuates lipopolysaccharide-induced acute kidney injury.

    PubMed

    Bi, Fangfang; Chen, Fang; Li, Yanning; Wei, Ai; Cao, Wangsen

    2018-05-05

    Renal anti-aging protein Klotho exhibits impressive properties of anti-inflammation and renal protection, however is suppressed early after renal injury, making Klotho restoration an attractive strategy of treating renal inflammatory disorders. Here, we reported that Klotho is enriched in macrophages and Klotho preservation by Rhein, an anthraquinone derived from medicinal plant rhubarb, attenuates lipopolysaccharide (LPS)-induced acute inflammation essentially via promoting toll-like receptor 4 (TLR4) degradation. LPS-induced pro-inflammatory NF-κB signaling and cytokine expressions coincided with Klotho repression and toll-like receptor 4 (TLR4) elevation in macrophages, renal epithelial cells, and acutely- inflamed kidney. Intriguingly, Rhein treatment effectively corrected the inverted alterations of Klotho and TLR4 and mitigated the TLR4 downstream inflammatory response in a Klotho restoration and TLR4 repression-dependent manner. Klotho inducibly associated with TLR4 after LPS stimulation and suppressed TLR4 protein abundance mainly via a proteolytic process sensitive to the inhibition of Klotho's putative β-glucuronidase activity. Consistently, Klotho knockdown by RNA interferences largely diminished the anti-inflammatory and renal protective effects of Rhein in a mouse model of acute kidney injury incurred by LPS. Thus, Klotho suppression of TLR4 via deglycosylation negatively controls TLR-associated inflammatory signaling and the endogenous Klotho preservation by Rhein or possibly other natural or synthetic compounds possesses promising potentials in the clinical treatment of renal inflammatory disorders. • Klotho is highly expressed in macrophages and repressed by LPS in vitro and in vivo. • Klotho inhibits LPS-induced TLR4 accumulation and the downstream signaling. • Klotho decreases TLR4 via a deglycosylation-associated proteolytic process. • Rhein effectively prevents acute inflammation-incurred Klotho suppression. • Rhein reversal of

  13. The autoimmunity-associated gene PTPN22 potentiates toll-like receptor-driven, type 1 interferon-dependent immunity.

    PubMed

    Wang, Yaya; Shaked, Iftach; Stanford, Stephanie M; Zhou, Wenbo; Curtsinger, Julie M; Mikulski, Zbigniew; Shaheen, Zachary R; Cheng, Genhong; Sawatzke, Kristy; Campbell, Amanda M; Auger, Jennifer L; Bilgic, Hatice; Shoyama, Fernanda M; Schmeling, David O; Balfour, Henry H; Hasegawa, Kiminori; Chan, Andrew C; Corbett, John A; Binstadt, Bryce A; Mescher, Matthew F; Ley, Klaus; Bottini, Nunzio; Peterson, Erik J

    2013-07-25

    Immune cells sense microbial products through Toll-like receptors (TLR), which trigger host defense responses including type 1 interferons (IFNs) secretion. A coding polymorphism in the protein tyrosine phosphatase nonreceptor type 22 (PTPN22) gene is a susceptibility allele for human autoimmune and infectious disease. We report that Ptpn22 selectively regulated type 1 IFN production after TLR engagement in myeloid cells. Ptpn22 promoted host antiviral responses and was critical for TLR agonist-induced, type 1 IFN-dependent suppression of inflammation in colitis and arthritis. PTPN22 directly associated with TNF receptor-associated factor 3 (TRAF3) and promotes TRAF3 lysine 63-linked ubiquitination. The disease-associated PTPN22W variant failed to promote TRAF3 ubiquitination, type 1 IFN upregulation, and type 1 IFN-dependent suppression of arthritis. The findings establish a candidate innate immune mechanism of action for a human autoimmunity "risk" gene in the regulation of host defense and inflammation. Copyright © 2013 Elsevier Inc. All rights reserved.

  14. Characterization of Toll-like receptor 3 gene in large yellow croaker, Pseudosciaena crocea.

    PubMed

    Huang, Xue-Na; Wang, Zhi-Yong; Yao, Cui-Luan

    2011-07-01

    Toll-like receptor 3 (TLR3) plays an important role in innate immune responses. In this report, the full-length cDNA sequence and genomic structure of Pseudosciaena crocea TLR3 (PcTLR3) were identified and characterized. The full-length cDNA of PcTLR3 was of 3384 bp, including a 5'-terminal untranslated region (UTR) of 65 bp, a 3'-terminal UTR of 589 bp and an open reading frame (ORF) of 2730 bp encoding a polypeptide of 909 amino acid residues. The full-length genome sequence of PcTLR3 was composed of 5721 nucleotides, including five exons and four introns. The putative PcTLR3 protein contained a signal peptide sequence, 16 leucine-rich repeat (LRR) motifs, a transmembrane region and a Toll/interleukin-1 receptor (TIR) domain. Quantitative real-time reverse transcription PCR analysis revealed a broad expression of PcTLR3 in most tissues, with the predominant expression in liver, then intestine, and the weakest expression in blood cells. The expression of PcTLR3 after injection with poly inosinic:cytidylic (I:C) and Vibrio parahemolyticus was tested in spleen, blood cells and liver. The results indicated that PcTLR3 transcripts could be induced in the three tissues by injection with poly I:C. The highest expression was in the blood cells with 43.5 times (at 6h) greater expression than in the control (p<0.05). In addition, after V. parahemolyticus challenge, a moderate up-regulation and down-regulation of PcTLR3 was found in blood cells and liver, respectively. Our results suggested that PcTLR3 might play an important role in fish's defense against both viral and bacterial infection. Copyright © 2011 Elsevier Ltd. All rights reserved.

  15. Toll-Like Receptor Function in Acute Wounds

    PubMed Central

    Chen, Lin; DiPietro, Luisa A.

    2017-01-01

    Significance: Inflammation is an integral part of immune response and supports optimal wound healing in adults. Inflammatory cells such as neutrophils, macrophages, dendritic cells, lymphocytes, and mast cells produce important cytokines, chemokines, and growth factors. These immune cells interact with keratinocytes, fibroblasts, and endothelial cells (ECs), as well as the extracellular matrix within a complicated network that promotes and regulates wound healing. Aberrant and persistent inflammation may result in delayed wound healing, scar formation, or chronic wounds. Targeting the molecules involved in the inflammatory response may have great potential therapeutic value. Recent Advances and Critical Issues: Toll-like receptors (TLRs) are pattern recognition receptors that recognize pathogen-associated molecular patterns from microbes or danger-associated molecular patterns from damaged cells. The discovery of TLRs sheds new light on the mechanism by which the inflammatory or innate immune response is initiated in wound healing. Convincing evidence now shows that multiple types of cells, including infiltrating or resident inflammatory cells, keratinocytes, fibroblasts, and ECs, express specific types of TLRs. Experimental reduction of certain TLRs or treatment of wounds with TLR ligands has been shown to affect wound healing. A better understanding of the involvement of TLRs in the innate immune response during skin wound healing may suggest novel strategies to improve the quality of tissue repair. Future Directions: Despite the indisputable role of TLRs in regulating the immune response in acute wound healing, the functions of TLRs that are relevant to human wound healing and chronic wounds are poorly understood. PMID:29062591

  16. Assembly of oligomeric death domain complexes during Toll receptor signaling.

    PubMed

    Moncrieffe, Martin C; Grossmann, J Günter; Gay, Nicholas J

    2008-11-28

    The Drosophila Toll receptor is activated by the endogenous protein ligand Spätzle in response to microbial stimuli in immunity and spatial cues during embryonic development. Downstream signaling is mediated by the adaptor proteins Tube, the kinase Pelle, and the Drosophila homologue of myeloid differentiation primary response protein (dMyD88). Here we have characterized heterodimeric (dMyD88-Tube) and heterotrimeric (dMyD88-Tube-Pelle) death domain complexes. We show that both the heterodimeric and heterotrimeric complexes form kidney-shaped structures and that Tube is bivalent and has separate high affinity binding sites for dMyD88 and Pelle. Additionally we found no interaction between the isolated death domains of Pelle and dMyD88. These results indicate that the mode of assembly of the heterotrimeric dMyD88-Tube-Pelle complex downstream of the activated Toll receptor is unique. The measured dissociation constants for the interaction between the death domains of dMyD88 and Tube and of Pelle and a preformed dMyD88-Tube complex are used to propose a model of the early postreceptor events in Drosophila Toll receptor signaling.

  17. Assembly of Oligomeric Death Domain Complexes during Toll Receptor Signaling*

    PubMed Central

    Moncrieffe, Martin C.; Grossmann, J. Günter; Gay, Nicholas J.

    2008-01-01

    The Drosophila Toll receptor is activated by the endogenous protein ligand Spätzle in response to microbial stimuli in immunity and spatial cues during embryonic development. Downstream signaling is mediated by the adaptor proteins Tube, the kinase Pelle, and the Drosophila homologue of myeloid differentiation primary response protein (dMyD88). Here we have characterized heterodimeric (dMyD88-Tube) and heterotrimeric (dMyD88-Tube-Pelle) death domain complexes. We show that both the heterodimeric and heterotrimeric complexes form kidney-shaped structures and that Tube is bivalent and has separate high affinity binding sites for dMyD88 and Pelle. Additionally we found no interaction between the isolated death domains of Pelle and dMyD88. These results indicate that the mode of assembly of the heterotrimeric dMyD88-Tube-Pelle complex downstream of the activated Toll receptor is unique. The measured dissociation constants for the interaction between the death domains of dMyD88 and Tube and of Pelle and a preformed dMyD88-Tube complex are used to propose a model of the early postreceptor events in Drosophila Toll receptor signaling. PMID:18829464

  18. De Novo Transcriptome Analysis Shows That SAV-3 Infection Upregulates Pattern Recognition Receptors of the Endosomal Toll-Like and RIG-I-Like Receptor Signaling Pathways in Macrophage/Dendritic Like TO-Cells.

    PubMed

    Xu, Cheng; Evensen, Øystein; Munang'andu, Hetron

    2016-04-21

    A fundamental step in cellular defense mechanisms is the recognition of "danger signals" made of conserved pathogen associated molecular patterns (PAMPs) expressed by invading pathogens, by host cell germ line coded pattern recognition receptors (PRRs). In this study, we used RNA-seq and the Kyoto encyclopedia of genes and genomes (KEGG) to identify PRRs together with the network pathway of differentially expressed genes (DEGs) that recognize salmonid alphavirus subtype 3 (SAV-3) infection in macrophage/dendritic like TO-cells derived from Atlantic salmon (Salmo salar L) headkidney leukocytes. Our findings show that recognition of SAV-3 in TO-cells was restricted to endosomal Toll-like receptors (TLRs) 3 and 8 together with RIG-I-like receptors (RLRs) and not the nucleotide-binding oligomerization domain-like receptors NOD-like receptor (NLRs) genes. Among the RLRs, upregulated genes included the retinoic acid inducible gene I (RIG-I), melanoma differentiation association 5 (MDA5) and laboratory of genetics and physiology 2 (LGP2). The study points to possible involvement of the tripartite motif containing 25 (TRIM25) and mitochondrial antiviral signaling protein (MAVS) in modulating RIG-I signaling being the first report that links these genes to the RLR pathway in SAV-3 infection in TO-cells. Downstream signaling suggests that both the TLR and RLR pathways use interferon (IFN) regulatory factors (IRFs) 3 and 7 to produce IFN-a2. The validity of RNA-seq data generated in this study was confirmed by quantitative real time qRT-PCR showing that genes up- or downregulated by RNA-seq were also up- or downregulated by RT-PCR. Overall, this study shows that de novo transcriptome assembly identify key receptors of the TLR and RLR sensors engaged in host pathogen interaction at cellular level. We envisage that data presented here can open a road map for future intervention strategies in SAV infection of salmon.

  19. Large supramolecular structures of 33-mer gliadin peptide activate toll-like receptors in macrophages.

    PubMed

    Herrera, María Georgina; Pizzuto, Malvina; Lonez, Caroline; Rott, Karsten; Hütten, Andreas; Sewald, Norbert; Ruysschaert, Jean-Marie; Dodero, Veronica Isabel

    2018-04-22

    Gliadin, an immunogenic protein present in wheat, is not fully degraded by humans and after the normal gastric and pancreatic digestion, the immunodominant 33-mer gliadin peptide remains unprocessed. The 33-mer gliadin peptide is found in human faeces and urine, proving not only its proteolytic resistance in vivo but more importantly its transport through the entire human body. Here, we demonstrate that 33-mer supramolecular structures larger than 220 nm induce the overexpression of nuclear factor kappa B (NF-κB) via a specific Toll-like Receptor (TLR) 2 and (TLR) 4 dependent pathway and the secretion of pro-inflammatory cytokines such as IP-10/CXCL10 and TNF-α. Using helium ion microscopy, we elucidated the initial stages of oligomerisation of 33-mer gliadin peptide, showing that rod-like oligomers are nucleation sites for protofilament formation. The relevance of the 33-mer supramolecular structures in the early stages of the disease is paving new perspectives in the understanding of gluten-related disorders. Copyright © 2018. Published by Elsevier Inc.

  20. Symbiotic Bacterial Metabolites Regulate Gastrointestinal Barrier Function via the Xenobiotic Sensor PXR and Toll-like Receptor 4

    PubMed Central

    Venkatesh, Madhukumar; Mukherjee, Subhajit; Wang, Hongwei; Li, Hao; Sun, Katherine; Benechet, Alaxandre P.; Qiu, Zhijuan; Maher, Leigh; Redinbo, Matthew R.; Phillips, Robert S.; Fleet, James C.; Kortagere, Sandhya; Mukherjee, Paromita; Fasano, Alessio; Le Ven, Jessica; Nicholson, Jeremy K.; Dumas, Marc E.; Khanna, Kamal M.; Mani, Sridhar

    2014-01-01

    SUMMARY Intestinal microbial metabolites are conjectured to affect mucosal integrity through an incompletely characterized mechanism. Here we showed microbial-specific indoles regulated intestinal barrier function through the xenobiotic sensor, pregnane X receptor (PXR). Indole 3-propionic acid (IPA), in the context of indole, is as a ligand for PXR in vivo, and IPA down-regulated enterocyte TNF–α while up-regulated junctional protein-coding mRNAs. PXR-deficient (Nr1i2−/−) mice showed a distinctly “leaky” gut physiology coupled with up-regulation of the Toll-like receptor (TLR) signaling pathway. These defects in the epithelial barrier were corrected in Nr1i2−/−Tlr4−/− mice. Our results demonstrate that a direct chemical communication between the intestinal symbionts and PXR regulates mucosal integrity through a pathway which involves luminal sensing and signaling by TLR4. PMID:25065623

  1. Genetic variation in Toll-like receptors and disease susceptibility.

    PubMed

    Netea, Mihai G; Wijmenga, Cisca; O'Neill, Luke A J

    2012-05-18

    Toll-like receptors (TLRs) are key initiators of the innate immune response and promote adaptive immunity. Much has been learned about the role of TLRs in human immunity from studies linking TLR genetic variation with disease. First, monogenic disorders associated with complete deficiency in certain TLR pathways, such as MyD88-IRAK4 or TLR3-Unc93b-TRIF-TRAF3, have demonstrated the specific roles of these pathways in host defense against pyogenic bacteria and herpesviruses, respectively. Second, common polymorphisms in genes encoding several TLRs and associated genes have been associated with both infectious and autoimmune diseases. The study of genetic variation in TLRs in various populations combined with information on infection has demonstrated complex interaction between genetic variation in TLRs and environmental factors. This interaction explains the differences in the effect of TLR polymorphisms on susceptibility to infection and autoimmune disease in various populations.

  2. Toll-like receptor 4-related immunostimulatory polysaccharides: Primary structure, activity relationships, and possible interaction models.

    PubMed

    Zhang, Xiaorui; Qi, Chunhui; Guo, Yan; Zhou, Wenxia; Zhang, Yongxiang

    2016-09-20

    Toll-like receptor (TLR) 4 is an important polysaccharide receptor; however, the relationships between the structures and biological activities of TLR4 and polysaccharides remain unknown. Many recent findings have revealed the primary structure of TLR4/MD-2-related polysaccharides, and several three-dimensional structure models of polysaccharide-binding proteins have been reported; and these models provide insights into the mechanisms through which polysaccharides interact with TLR4. In this review, we first discuss the origins of polysaccharides related to TLR4, including polysaccharides from higher plants, fungi, bacteria, algae, and animals. We then briefly describe the glucosidic bond types of TLR4-related heteroglycans and homoglycans and describe the typical molecular weights of TLR4-related polysaccharides. The primary structures and activity relationships of polysaccharides with TLR4/MD-2 are also discussed. Finally, based on the existing interaction models of LPS with TLR4/MD-2 and linear polysaccharides with proteins, we provide insights into the possible interaction models of polysaccharide ligands with TLR4/MD-2. To our knowledge, this review is the first to summarize the primary structures and activity relationships of TLR4-related polysaccharides and the possible mechanisms of interaction for TLR4 and TLR4-related polysaccharides. Copyright © 2016 Elsevier Ltd. All rights reserved.

  3. The phosphoproteome of toll-like receptor-activated macrophages

    PubMed Central

    Weintz, Gabriele; Olsen, Jesper V; Frühauf, Katja; Niedzielska, Magdalena; Amit, Ido; Jantsch, Jonathan; Mages, Jörg; Frech, Cornelie; Dölken, Lars; Mann, Matthias; Lang, Roland

    2010-01-01

    Recognition of microbial danger signals by toll-like receptors (TLR) causes re-programming of macrophages. To investigate kinase cascades triggered by the TLR4 ligand lipopolysaccharide (LPS) on systems level, we performed a global, quantitative and kinetic analysis of the phosphoproteome of primary macrophages using stable isotope labelling with amino acids in cell culture, phosphopeptide enrichment and high-resolution mass spectrometry. In parallel, nascent RNA was profiled to link transcription factor (TF) phosphorylation to TLR4-induced transcriptional activation. We reproducibly identified 1850 phosphoproteins with 6956 phosphorylation sites, two thirds of which were not reported earlier. LPS caused major dynamic changes in the phosphoproteome (24% up-regulation and 9% down-regulation). Functional bioinformatic analyses confirmed canonical players of the TLR pathway and highlighted other signalling modules (e.g. mTOR, ATM/ATR kinases) and the cytoskeleton as hotspots of LPS-regulated phosphorylation. Finally, weaving together phosphoproteome and nascent transcriptome data by in silico promoter analysis, we implicated several phosphorylated TFs in primary LPS-controlled gene expression. PMID:20531401

  4. Mechanisms controlling nucleic acid-sensing Toll-like receptors.

    PubMed

    Miyake, Kensuke; Shibata, Takuma; Ohto, Umeharu; Shimizu, Toshiyuki; Saitoh, Shin-Ichiroh; Fukui, Ryutaro; Murakami, Yusuke

    2018-03-08

    Nucleic acid (NA)-sensing Toll-like receptors (TLRs) respond to DNA/RNA derived from pathogens and dead cells. Structural studies have revealed a variety of molecular mechanisms by which TLRs sense NAs. Double-stranded RNA and single-stranded DNA directly bind to TLR3 and TLR9, respectively, whereas TLR7 and TLR8 bind to nucleosides and oligoribonucleotides derived from RNAs. Activation of ligand-bound TLRs is influenced by the functional status of TLRs. Proteolytic cleavage of NA-sensing TLRs enables ligand-dependent TLR dimerization. Trafficking of ligand-activated TLRs in endosomal and lysosomal compartments is requisite for production of type I interferons. Activation of NA-sensing TLRs is required for the control of viruses such as herpes simplex virus and endogenous retroviruses. On the other hand, excessive activation of NA-sensing TLRs drives disease progression in a variety of inflammatory diseases including systemic lupus erythematosus, heart failure, arthritis and non-alcoholic steatohepatitis. NA-sensing TLRs are targets for therapeutic intervention in these diseases. We here focus on our recent progresses in our understanding of NA-sensing TLRs.

  5. Toll-like receptors in inflammatory bowel diseases: A decade later

    PubMed Central

    Cario, Elke

    2010-01-01

    Differential alteration of Toll-like receptor (TLR) expression in inflammatory bowel disease (IBD) was first described 10 years ago. Since then, studies from many groups have led to the current concept that TLRs represent key mediators of innate host defense in the intestine, involved in maintaining mucosal as well as commensal homeostasis. Recent findings in diverse murine models of colitis have helped to reveal the mechanistic importance of TLR dysfunction in IBD pathogenesis. It has become evident that environment, genetics, and host immunity form a multidimensional and highly interactive regulatory triad that controls TLR function in the intestinal mucosa. Imbalanced relationships within this triad may promote aberrant TLR signaling, critically contributing to acute and chronic intestinal inflammatory processes in IBD colitis and associated cancer. (Inflamm Bowel Dis 2010) PMID:20803699

  6. ROLE OF TOLL LIKE RECEPTORS ON PULMONARY INFLAMMATORY RESPONSES TO SIZE FRACTIONATED COMBUSTION AND AMBIENT AIR PARTICLES.

    EPA Science Inventory

    C3H/HeJ mice feature a single point mutation in the Toll like receptor 4 gene which renders these animals resistant to a number of pro-inflammatory agents including lipopolysaccharide and ozone. This study compared pulmonary inflammatory responses in endotoxin resistant (C3H/HeJ...

  7. Evolution of toll-like receptors in the context of terrestrial ungulates and cetaceans diversification.

    PubMed

    Ishengoma, Edson; Agaba, Morris

    2017-02-16

    Toll-like receptors (TLRs) are the frontline actors in the innate immune response to various pathogens and are expected to be targets of natural selection in species adapted to habitats with contrasting pathogen burdens. The recent publication of genome sequences of giraffe and okapi together afforded the opportunity to examine the evolution of selected TLRs in broad range of terrestrial ungulates and cetaceans during their complex habitat diversification. Through direct sequence comparisons and standard evolutionary approaches, the extent of nucleotide and protein sequence diversity in seven Toll-like receptors (TLR2, TLR3, TLR4, TLR5, TLR7, TLR9 and TLR10) between giraffe and closely related species was determined. In addition, comparison of the patterning of key TLR motifs and domains between giraffe and related species was performed. The quantification of selection pressure and divergence on TLRs among terrestrial ungulates and cetaceans was also performed. Sequence analysis shows that giraffe has 94-99% nucleotide identity with okapi and cattle for all TLRs analyzed. Variations in the number of Leucine-rich repeats were observed in some of TLRs between giraffe, okapi and cattle. Patterning of key TLR domains did not reveal any significant differences in the domain architecture among giraffe, okapi and cattle. Molecular evolutionary analysis for selection pressure identifies positive selection on key sites for all TLRs examined suggesting that pervasive evolutionary pressure has taken place during the evolution of terrestrial ungulates and cetaceans. Analysis of positively selected sites showed some site to be part of Leucine-rich motifs suggesting functional relevance in species-specific recognition of pathogen associated molecular patterns. Notably, clade analysis reveals significant selection divergence between terrestrial ungulates and cetaceans in viral sensing TLR3. Mapping of giraffe TLR3 key substitutions to the structure of the receptor indicates that

  8. Toll-like receptor 3 as an immunotherapeutic target for KRAS mutated colorectal cancer

    PubMed Central

    Maitra, Radhashree; Augustine, Titto; Dayan, Yitzchak; Chandy, Carol; Coffey, Matthew; Goel, Sanjay

    2017-01-01

    New therapeutic interventions are essential for improved management of patients with metastatic colorectal cancer (mCRC). This is especially critical for those patients whose tumors harbor a mutation in the KRAS oncogene (40-45% of all patients). This patient cohort is excluded from receiving anti-EGFR monoclonal antibodies that have added a significant therapeutic benefit for KRAS wild type CRC patients. Reovirus, a double stranded (ds) RNA virus is in clinical development for patients with chemotherapy refractory KRAS mutated tumors. Toll Like Receptor (TLR) 3, a member of the toll like receptor family of the host innate immune system is the pattern recognition motif for dsRNA pathogens. Using TLR3 expressing commercial HEK-Blue™-hTLR3 cells we confirm that TLR3 is the host pattern recognition motif responsible for the detection of reovirus. Further, our investigation with KRAS mutated HCT116 cell line showed that effective expression of host TLR3 dampens the infection potential of reovirus by mounting a robust innate immune response. Down regulation of TLR3 expression with siRNA improves the anticancer activity of reovirus. In vivo experiments using human CRC cells derived xenografts in athymic mice further demonstrate the beneficial effects of TLR3 knock down by improving tumor response rates to reovirus. Strategies to mitigate the TLR3 response pathway can be utilized as a tool towards improved reovirus efficacy to specifically target the dissemination of KRAS mutated CRC. PMID:28422714

  9. Adaptor protein-3 is required in dendritic cells for optimal Toll-like receptor signaling from phagosomes and antigen presentation to CD4+ T cells

    PubMed Central

    Mantegazza, Adriana R.; Guttentag, Susan H.; El-Benna, Jamel; Sasai, Miwa; Iwasaki, Akiko; Shen, Hao; Laufer, Terri M.; Marks, Michael S.

    2012-01-01

    SUMMARY Effective major histocompatibility complex-II (MHC-II) antigen presentation from phagocytosed particles requires phagosome-intrinsic toll-like receptor (TLR) signaling, but the molecular mechanisms underlying TLR delivery to phagosomes and how signaling regulates antigen presentation are incompletely understood. We show a requirement in dendritic cells (DCs) for adaptor protein-3 (AP-3) in efficient TLR recruitment to phagosomes and MHC-II presentation of antigens internalized by phagocytosis but not receptor-mediated endocytosis. DCs from AP-3-deficient pearl mice elicited impaired CD4+ T cell activation and Th1 effector function to particulate antigen in vitro and to recombinant Listeria monocytogenes infection in vivo. Whereas phagolysosome maturation and peptide:MHC-II complex assembly proceeded normally in pearl DCs, peptide:MHC-II export to the cell surface was impeded. This correlated with reduced TLR4 recruitment and proinflammatory signaling from phagosomes by particulate TLR ligands. We propose that AP-3-dependent TLR delivery from endosomes to phagosomes and subsequent signaling mobilize peptide:MHC-II export from intracellular stores. PMID:22560444

  10. Toll-like receptor polymorphisms in malaria-endemic populations

    PubMed Central

    Greene, Jennifer A; Moormann, Ann M; Vulule, John; Bockarie, Moses J; Zimmerman, Peter A; Kazura, James W

    2009-01-01

    Background Toll-like receptors (TLR) and related downstream signaling pathways of innate immunity have been implicated in the pathogenesis of Plasmodium falciparum malaria. Because of their potential role in malaria pathogenesis, polymorphisms in these genes may be under selective pressure in populations where this infectious disease is endemic. Methods A post-PCR Ligation Detection Reaction-Fluorescent Microsphere Assay (LDR-FMA) was developed to determine the frequencies of TLR2, TLR4, TLR9, MyD88-Adaptor Like Protein (MAL) single nucleotide polymorphisms (SNPs), and TLR2 length polymorphisms in 170 residents of two regions of Kenya where malaria transmission is stable and high (holoendemic) or episodic and low, 346 residents of a malaria holoendemic region of Papua New Guinea, and 261 residents of North America of self-identified ethnicity. Results The difference in historical malaria exposure between the two Kenyan sites has significantly increased the frequency of malaria protective alleles glucose-6-phoshpate dehydrogenase (G6PD) and Hemoglobin S (HbS) in the holoendemic site compared to the episodic transmission site. However, this study detected no such difference in the TLR2, TLR4, TLR9, and MAL allele frequencies between the two study sites. All polymorphisms were in Hardy Weinberg Equilibrium in the Kenyan and Papua New Guinean populations. TLR9 SNPs and length polymorphisms within the TLR2 5' untranslated region were the only mutant alleles present at a frequency greater than 10% in all populations. Conclusion Similar frequencies of TLR2, TLR4, TLR9, and MAL genetic polymorphisms in populations with different histories of malaria exposure suggest that these innate immune pathways have not been under strong selective pressure by malaria. Genotype frequencies are consistent with Hardy-Weinberg Equilibrium and the Neutral Theory, suggesting that genetic drift has influenced allele frequencies to a greater extent than selective pressure from malaria or any

  11. The role of MAPK in CD4{sup +} T cells toll-like receptor 9-mediated signaling following HHV-6 infection

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Chi, Jing; Wang, Fang; Li, Lingyun

    2012-01-05

    Human herpesvirus-6 (HHV-6) is an important immunosuppressive and immunomodulatory virus that primarily infects immune cells (mainly CD4{sup +} T cells) and strongly suppresses the proliferation of infected cells. Toll-like receptors are pattern-recognition receptors essential for the development of an appropriate innate immune defense against infection. To understand the role of CD4{sup +} T cells in the innate response to HHV-6 infection and the involvement of TLRs, we used an in vitro infection model and observed that the infection of CD4{sup +} T cells resulted in the activation of JNK/SAPK via up-regulation of toll-like receptor 9 (TLR9). Associated with JNK activation,more » annexin V-PI staining indicated that HHV-6A was a strong inducer of apoptosis. Apoptotic response associated cytokines, IL-6 and TNF-{alpha} also induced by HHV-6A infection.« less

  12. Mechanisms of Toll-like receptor 4 endocytosis reveal a common immune-evasion strategy used by pathogenic and commensal bacteria

    PubMed Central

    Tan, Yunhao; Zanoni, Ivan; Cullen, Thomas W.; Goodman, Andrew L.; Kagan, Jonathan C.

    2015-01-01

    Microbe-induced receptor trafficking has emerged as an essential means to promote innate immune signal transduction. Upon detection of bacterial lipopolysaccharides (LPS), CD14 induces an inflammatory endocytosis pathway that delivers Toll-like Receptor 4 (TLR4) to endosomes. Although several regulators of CD14-dependent TLR4 endocytosis have been identified, the cargo selection mechanism during this process remains unknown. We reveal that, in contrast to classic cytosolic interactions that promoted the endocytosis of transmembrane receptors, TLR4 was selected as cargo for inflammatory endocytosis entirely through extracellular interactions. Mechanistically, the extracellular protein MD-2 bound to and dimerized TLR4 in order to promote this endocytic event. Our analysis of LPS variants from human pathogens and gut commensals revealed a common mechanism by which bacteria prevent inflammatory endocytosis. We suggest that evasion of CD14-dependent endocytosis is an attribute that transcends the concept of pathogenesis, and may be a fundamental feature of bacteria that inhabit eukaryotic hosts. PMID:26546281

  13. Platelets Toll-like receptor-4 in Crohns disease.

    PubMed

    Schmid, Werner; Novacek, Gottfried; Vogelsang, Harald; Papay, Pavol; Primas, Christian; Eser, Alexander; Panzer, Simon

    2017-02-01

    Platelets are activated in Crohn's disease (CD) and interplay with leukocytes. Engagement of Toll-like receptor-4 (TLR-4), which is expressed in human platelets, may be involved in crosstalks between platelets and leukocytes leading to their mutual activation for host defense. Human neutrophil peptides (HNPs), lipoprotein binding peptides, and sCD14 were determined by enzyme-linked immunosorbent assays in 42 patients with active CD, in 43 patients with CD in remission, and in 30 healthy individuals. Neutrophil-platelet aggregates and binding of the TLR-4 monoclonal antibody to platelets were determined by flow cytometry. Levels of HNPs were higher in patients with CD than in controls (P = 0.0003 vs. active CD and P = 0.01 vs. CD in remission). Likewise, neutrophils with adhering platelets were higher in patients with active CD than in controls (P = 0.004). Binding of the TLR-4 antibody in patients with active CD was similar to that in controls, while patients in remission had significantly higher binding capacities (P = 0.59 and P = 0.003). Incubation of plasma from patients with active disease or patients in remission with platelets from healthy controls confirmed lower binding of the TLR-4 antibody in the presence of plasma from active diseased patients compared to controls (P = 0.039), possibly due to high levels of lipopolysaccharides, as suggested by high levels of sCD14 and lipoprotein binding protein. Our study indicates involvement of platelet TLR-4 in enhancing the secretion of antimicrobial peptides from neutrophils. While platelet aggregation can be due to a variety of mechanisms in inflammatory disease, the mutual activation of platelets and neutrophils may augment host defense. © 2016 Stichting European Society for Clinical Investigation Journal Foundation.

  14. Mesenchymal stem cells cannot affect mRNA expression of toll-like receptors in different tissues during sepsis.

    PubMed

    Pedrazza, Leonardo; Pereira, Talita Carneiro Brandão; Abujamra, Ana Lucia; Nunes, Fernanda Bordignon; Bogo, Maurício Reis; de Oliveira, Jarbas Rodrigues

    2017-07-01

    Experimental animal models and human clinical studies support a crucial role for TLRs in infectious diseases. The aim of this study was to test the ability of MSCs, which have immunomodulatory effects, of altering the mRNA expression of toll-like receptors during a experimental model of sepsis in different tissues. Three experimental groups (male C57BL/6 mice) were formed for the test: control group, untreated septic group and septic group treated with MSCs (1 × 10 6 cells/animal). Lungs, cortex, kidney, liver and colon tissue were dissected after 12 h of sepsis induction and TLR2/3/4/9 mRNA were evaluated by RT-qPCR. We observed a decrease of TLR2 and 9 mRNA expression in the liver of the sepsis group, while TLR3 was decreased in the lung and liver. No change was found between the sepsis group and the sepsis + MSC group. In this model of experimental sepsis the MSCs were unable to modify the mRNA expression of the different toll-like receptors evaluated.

  15. Genetic Diversity of Toll-Like Receptors and Immunity to M. leprae Infection

    PubMed Central

    Hart, Bryan E.; Tapping, Richard I.

    2012-01-01

    Genetic association studies of leprosy cohorts across the world have identified numerous polymorphisms which alter susceptibility and outcome to infection with Mycobacterium leprae. As expected, many of the polymorphisms reside within genes that encode components of the innate and adaptive immune system. Despite the preponderance of these studies, our understanding of the mechanisms that underlie these genetic associations remains sparse. Toll-like receptors (TLRs) have emerged as an essential family of innate immune pattern recognition receptors which play a pivotal role in host defense against microbes, including pathogenic strains of mycobacteria. This paper will highlight studies which have uncovered the association of specific TLR gene polymorphisms with leprosy or tuberculosis: two important diseases resulting from mycobacterial infection. This analysis will focus on the potential influence these polymorphic variants have on TLR expression and function and how altered TLR recognition or signaling may contribute to successful antimycobacterial immunity. PMID:22529866

  16. Painful Pathways Induced by Toll-like Receptor Stimulation of Dorsal Root Ganglion Neurons

    PubMed Central

    Qi, Jia; Buzas, Krisztina; Fan, Huiting; Cohen, Jeffrey I.; Wang, Kening; Mont, Erik; Klinman, Dennis; Oppenheim, Joost J.; Howard, O.M. Zack

    2011-01-01

    We hypothesize that innate immune signals from infectious organisms and/or injured tissues may activate peripheral neuronal pain signals. In this study, we demonstrated that toll-like receptors 3/7/9 (TLRs) are expressed by human dorsal root ganglion neurons (DRGNs) and in cultures of primary mouse DRGNs. Stimulation of murine DRGNs with TLR ligands induced expression and production of proinflammatory chemokines and cytokines CCL5 (RANTES), CXCL10 (IP10), interleukin-1alpha, interleukin-1beta, and prostaglandin E2 (PGE2), which have previously been shown to augment pain. Further, TLR ligands up-regulated the expression of a nociceptive receptor transient receptor potential vanilloid type 1 (TRPV1), and enhanced calcium flux by TRPV1 expressing DRGNs. Using a tumor-induced temperature sensitivity model, we showed that in vivo administration of a TLR9 antagonist, known as a suppressive ODN, blocked tumor-induced temperature sensitivity. Taken together, these data indicate that stimulation of peripheral neurons by TLR ligands can induce nerve pain. PMID:21515789

  17. Trial Watch: Toll-like receptor agonists for cancer therapy.

    PubMed

    Vacchelli, Erika; Eggermont, Alexander; Sautès-Fridman, Catherine; Galon, Jérôme; Zitvogel, Laurence; Kroemer, Guido; Galluzzi, Lorenzo

    2013-08-01

    Toll-like receptors (TLRs) have long been known for their ability to initiate innate immune responses upon exposure to conserved microbial components such as lipopolysaccharide (LPS) and double-stranded RNA. More recently, this family of pattern recognition receptors has been attributed a critical role in the elicitation of anticancer immune responses, raising interest in the development of immunochemotherapeutic regimens based on natural or synthetic TLR agonists. In spite of such an intense wave of preclinical and clinical investigation, only three TLR agonists are currently licensed by FDA for use in cancer patients: bacillus Calmette-Guérin (BCG), an attenuated strain of Mycobacterium bovis that operates as a mixed TLR2/TLR4 agonist; monophosphoryl lipid A (MPL), a derivative of Salmonella minnesota that functions as a potent agonist of TLR4; and imiquimod, a synthetic imidazoquinoline that activates TLR7. One year ago, in the August and September issues of OncoImmunology , we described the main biological features of TLRs and discussed the progress of clinical studies evaluating the safety and therapeutic potential of TLR agonists in cancer patients. Here, we summarize the latest developments in this exciting area of research, focusing on preclinical studies that have been published during the last 13 mo and clinical trials launched in the same period to investigate the antineoplastic activity of TLR agonists.

  18. Activation of Toll-like receptors nucleates assembly of the MyDDosome signaling hub

    PubMed Central

    Latty, Sarah Louise; Sakai, Jiro; Hopkins, Lee; Verstak, Brett; Paramo, Teresa; Berglund, Nils A; Cammorota, Eugenia; Cicuta, Pietro; Gay, Nicholas J; Bond, Peter J; Klenerman, David

    2018-01-01

    Infection and tissue damage induces assembly of supramolecular organizing centres (SMOCs)), such as the Toll-like receptor (TLR) MyDDosome, to co-ordinate inflammatory signaling. SMOC assembly is thought to drive digital all-or-none responses, yet TLR activation by diverse microbes induces anything from mild to severe inflammation. Using single-molecule imaging of TLR4-MyDDosome signaling in living macrophages, we find that MyDDosomes assemble within minutes of TLR4 stimulation. TLR4/MD2 activation leads only to formation of TLR4/MD2 heterotetramers, but not oligomers, suggesting a stoichiometric mismatch between activated receptors and MyDDosomes. The strength of TLR4 signalling depends not only on the number and size of MyDDosomes formed but also how quickly these structures assemble. Activated TLR4, therefore, acts transiently nucleating assembly of MyDDosomes, a process that is uncoupled from receptor activation. These data explain how the oncogenic mutation of MyD88 (L265P) assembles MyDDosomes in the absence of receptor activation to cause constitutive activation of pro-survival NF-κB signalling. PMID:29368691

  19. PGE2 released by primary sensory neurons modulates Toll-like receptor 4 activities through an EP4 receptor-dependent process.

    PubMed

    Tse, Kai-Hei; Chow, Kevin B S; Wise, Helen

    2016-04-15

    Exogenous prostaglandin E2 (PGE2) displays mixed regulatory properties with regard to inflammatory gene expression in dorsal root ganglion (DRG) cells. We show here that endogenously-produced nanomolar concentrations of PGE2, such as that generated in response to Toll-like receptor 4 (TLR4) stimulation, inhibits both cyclooxygenase-2 (COX-2) and tumour necrosis factor alpha (TNFα) mRNA expression in DRG cells in an EP4 receptor-dependent manner. DRG neurons appear to be the major source of PGE2 in the DRG and likely serve as both an autocrine and paracrine system for limiting over-activation of both DRG neurons and glial cells in response to TLR4 stimulation. Copyright © 2016 Elsevier B.V. All rights reserved.

  20. Regulation of B1 cell migration by signals through Toll-like receptors

    PubMed Central

    Ha, Seon-ah; Tsuji, Masayuki; Suzuki, Keiichiro; Meek, Bob; Yasuda, Nobutaka; Kaisho, Tsuneyasu; Fagarasan, Sidonia

    2006-01-01

    Peritoneal B1 cells are known to generate large amounts of antibodies outside their residential site. These antibodies play an important role in the early defense against bacteria and viruses, before the establishment of adaptive immune responses. Although many stimuli, including antigen, lipopolysaccharide, or cytokines, have been shown to activate B1 cells and induce their differentiation into plasma cells, the molecular signals required for their egress from the peritoneal cavity are not understood. We demonstrate here that direct signals through Toll-like receptors (TLRs) induce specific, rapid, and transient down-regulation of integrins and CD9 on B1 cells, which is required for detachment from local matrix and a high velocity movement of cells in response to chemokines. Thus, we revealed an unexpected role for TLRs in governing the interplay between integrins, tetraspanins, and chemokine receptors required for B1 cell egress and, as such, in facilitating appropriate transition from innate to adaptive immune responses. PMID:17060475

  1. Toll like receptors TLR1/2, TLR6 and MUC5B as binding interaction partners with cytostatic proline rich polypeptide 1 in human chondrosarcoma.

    PubMed

    Galoian, Karina; Abrahamyan, Silva; Chailyan, Gor; Qureshi, Amir; Patel, Parthik; Metser, Gil; Moran, Alexandra; Sahakyan, Inesa; Tumasyan, Narine; Lee, Albert; Davtyan, Tigran; Chailyan, Samvel; Galoyan, Armen

    2018-01-01

    Metastatic chondrosarcoma is a bone malignancy not responsive to conventional therapies; new approaches and therapies are urgently needed. We have previously reported that mTORC1 inhibitor, antitumorigenic cytostatic proline rich polypeptide 1 (PRP-1), galarmin caused a significant upregulation of tumor suppressors including TET1/2 and SOCS3 (known to be involved in inflammatory processes), downregulation of oncoproteins and embryonic stem cell marker miR-302C and its targets Nanog, c-Myc and Bmi-1 in human chondrosarcoma. To understand better the mechanism of PRP-1 action it was very important to identify the receptor it binds to. Nuclear pathway receptor and GPCR assays indicated that PRP-1 receptors are not G protein coupled, neither do they belong to family of nuclear or orphan receptors. In the present study, we have demonstrated that PRP-1 binding interacting partners belong to innate immunity pattern recognition toll like receptors TLR1/2 and TLR6 and gel forming secreted mucin MUC5B. MUC5B was identified as PRP-1 receptor in human chondrosarcoma JJ012 cell line using Ligand-receptor capture technology. Toll like receptors TLR1/2 and TLR6 were identified as binding interaction partners with PRP-1 by western blot analysis in human chondrosarcoma JJ012 cell line lysates. Immunocytochemistry experiments confirmed the finding and indicated the localization of PRP-1 receptors in the tumor nucleus predominantly. TLR1/2, TLR6 and MUC5B were downregulated in human chondrosarcoma and upregulated in dose-response manner upon PRP-1 treatment. Experimental data indicated that in this cellular context the mentioned receptors had tumor suppressive function.

  2. Toll like receptors TLR1/2, TLR6 and MUC5B as binding interaction partners with cytostatic proline rich polypeptide 1 in human chondrosarcoma

    PubMed Central

    Galoian, Karina; Abrahamyan, Silva; Chailyan, Gor; Qureshi, Amir; Patel, Parthik; Metser, Gil; Moran, Alexandra; Sahakyan, Inesa; Tumasyan, Narine; Lee, Albert; Davtyan, Tigran; Chailyan, Samvel; Galoyan, Armen

    2018-01-01

    Metastatic chondrosarcoma is a bone malignancy not responsive to conventional therapies; new approaches and therapies are urgently needed. We have previously reported that mTORC1 inhibitor, antitumorigenic cytostatic proline rich polypeptide 1 (PRP-1), galarmin caused a significant upregulation of tumor suppressors including TET1/2 and SOCS3 (known to be involved in inflammatory processes), downregulation of oncoproteins and embryonic stem cell marker miR-302C and its targets Nanog, c-Myc and Bmi-1 in human chondrosarcoma. To understand better the mechanism of PRP-1 action it was very important to identify the receptor it binds to. Nuclear pathway receptor and GPCR assays indicated that PRP-1 receptors are not G protein coupled, neither do they belong to family of nuclear or orphan receptors. In the present study, we have demonstrated that PRP-1 binding interacting partners belong to innate immunity pattern recognition toll like receptors TLR1/2 and TLR6 and gel forming secreted mucin MUC5B. MUC5B was identified as PRP-1 receptor in human chondrosarcoma JJ012 cell line using Ligand-receptor capture technology. Toll like receptors TLR1/2 and TLR6 were identified as binding interaction partners with PRP-1 by western blot analysis in human chondrosarcoma JJ012 cell line lysates. Immunocytochemistry experiments confirmed the finding and indicated the localization of PRP-1 receptors in the tumor nucleus predominantly. TLR1/2, TLR6 and MUC5B were downregulated in human chondrosarcoma and upregulated in dose-response manner upon PRP-1 treatment. Experimental data indicated that in this cellular context the mentioned receptors had tumor suppressive function. PMID:29138803

  3. Toll-like receptor-2 exacerbates murine acute viral hepatitis.

    PubMed

    Bleau, Christian; Burnette, Mélanie; Filliol, Aveline; Piquet-Pellorce, Claire; Samson, Michel; Lamontagne, Lucie

    2016-10-01

    Viral replication in the liver is generally detected by cellular endosomal Toll-like receptors (TLRs) and cytosolic helicase sensors that trigger antiviral inflammatory responses. Recent evidence suggests that surface TLR2 may also contribute to viral detection through recognition of viral coat proteins but its role in the outcome of acute viral infection remains elusive. In this study, we examined in vivo the role of TLR2 in acute infections induced by the highly hepatotrophic mouse hepatitis virus (MHV) type 3 and weakly hepatotrophic MHV-A59 serotype. To address this, C57BL/6 (wild-type; WT) and TLR2 knockout (KO) groups of mice were intraperitoneally infected with MHV3 or MHV-A59. MHV3 infection provoked a fulminant hepatitis in WT mice, characterized by early mortality and high alanine and aspartate transaminase levels, histopathological lesions and viral replication whereas infection of TLR2 KO mice was markedly less severe. MHV-A59 provoked a comparable mild and subclinical hepatitis in WT and TLR2 KO mice. MHV3-induced fulminant hepatitis in WT mice correlated with higher hepatic expression of interferon-β, interleukin-6, tumour necrosis factor-α, CXCL1, CCL2, CXCL10 and alarmin (interleukin-33) than in MHV-A59-infected WT mice and in MHV3-infected TLR2 KO mice. Intrahepatic recruited neutrophils, natural killer cells, natural killer T cells or macrophages rapidly decreased in MHV3-infected WT mice whereas they were sustained in MHV-A59-infected WT mice and MHV3-infected TLR2 KO. MHV3 in vitro infection of macrophagic cells induced rapid and higher viral replication and/or interleukin-6 induction in comparison to MHV-A59, and depended on viral activation of TLR2 and p38 mitogen-activated protein kinase. Taken together, these results support a new aggravating inflammatory role for TLR2 in MHV3-induced acute fulminant hepatitis. © 2016 John Wiley & Sons Ltd.

  4. The effects of administration of ligands for Toll-like receptor 4 and 21 against Marek’s disease in chickens

    USDA-ARS?s Scientific Manuscript database

    Ligands for Toll-like receptors (TLRs) are known to stimulate immune responses, leading to protection against bacterial and viral pathogens. Here, we aimed to examine the effects of various TLR ligands on the development of Marek’s disease in chickens. Specific-pathogen free chickens were treated wi...

  5. Bacterial Fimbriae and Their Peptides Activate Human Gingival Epithelial Cells through Toll-Like Receptor 2

    PubMed Central

    Asai, Yasuyuki; Ohyama, Yoshinori; Gen, Keika; Ogawa, Tomohiko

    2001-01-01

    Gingival epithelial cells are a central component of the barrier between oral microflora and internal tissues. Host responses to periodontopathic bacteria and surface components containing fimbriae are thought to be important in the development and progression of periodontal diseases. To elucidate this mechanism, we established immortalized human gingival epithelial cells (HGEC) that were transfected with human papillomavirus. HGEC predominantly expressed Toll-like receptor (TLR) 2, but not TLR4 or CD14. They also induced interleukin-8 (IL-8) production when stimulated with Porphyromonas gingivalis fimbriae and Staphylococcus aureus peptidoglycan, but not Escherichia coli-type synthetic lipid A. Furthermore, an active synthetic peptide composed of residues 69 to 73 (ALTTE) of the fimbrial subunit protein, derived from P. gingivalis and similar to a common component of cell wall peptidoglycans in parasitic bacteria, N-acetylmuramyl-l-alanyl-d-isoglutamine (MDP), significantly induced IL-8 production and NF-κB activation in HGEC, and these cytokine-producing activities were augmented by a complex of soluble CD14 and lipopolysaccharide-binding protein (LBP). IL-8 production in HGEC stimulated with these bacterial components was clearly inhibited by mouse monoclonal antibody to human TLR2. These findings suggest that P. gingivalis fimbrial protein and its active peptide are capable of activating HGEC through TLR2. PMID:11705912

  6. Role of Toll-Like Receptors in Hepatitis C Virus Pathogenesis and Treatment.

    PubMed

    Ashfaq, Usman Ali; Iqbal, Muhammad Sarfaraz; Khaliq, Saba

    2016-01-01

    Viral infections are rising every day, and viruses appear to be the most dangerous pathogens in the world. Hepatitis C virus (HCV) is accepted as one of the major destructive factors of promoting severe hepatic disorders by infecting more than 180 million individuals throughout the world. Chronic infection caused by HCV poses a serious global health emergency and appears to be a powerful threat to humanity. Almost 20 years have passed since the disclosure of HCV, but even now, treatment preferences remain limited. Humans are born with a rapid and nonspecific mechanism to prevent viral attacks through Toll-like receptors (TLRs), which are evolutionary conserved cellular activator proteins responsible for recognizing specific components present on penetrating microbes and viruses. Recent research efforts in TLR biology suggest that targeting the TLRs and their signaling pathways during HCV infection could contribute to novel therapies against HCV. The mobilization of TLRs boosts antiviral communication and integrates the development of long-lasting acquired immune responses to limit viral pathogenesis. Both activation and suppression of TLRs are necessary for the efficient treatment of HCV. For the proper management and eradication of HCV, novel drugs that target TLRs and their signaling pathway are needed. This review summarizes the role of TLR signaling in HCV infection and treatment.

  7. Toll-like receptors and cytokines as surrogate biomarkers for evaluating vaginal immune response following microbicide administration.

    PubMed

    Gupta, Sadhana M; Aranha, Clara C; Mohanty, Madhu C; Reddy, K V R

    2008-01-01

    Topical microbicides are intended for frequent use by women in reproductive age. Hence, it is essential to evaluate their impact on mucosal immune function in the vagina. In the present study, we evaluated nisin, a naturally occurring antimicrobial peptide (AMP), for its efficacy as an intravaginal microbicide. Its effect on the vaginal immune function was determined by localizing Toll-like receptors (TLRs-3, 9) and cytokines (IL-4, 6 , 10 and TNF-alpha) in the rabbit cervicovaginal epithelium following intravaginal administration of high dose of nisin gel for 14 consecutive days. The results revealed no alteration in the expression of TLRs and cytokines at both protein and mRNA levels. However, in SDS gel-treated group, the levels were significantly upregulated with the induction of NF-kappaB signalling cascade. Thus, TLRs and cytokines appear as sensitive indicators for screening immunotoxic potential of candidate microbicides.

  8. Toll-like receptor 4 stimulation with the detoxified ligand monophosphoryl lipid A improves Alzheimer’s disease-related pathology

    PubMed Central

    Michaud, Jean-Philippe; Hallé, Maxime; Lampron, Antoine; Thériault, Peter; Préfontaine, Paul; Filali, Mohammed; Tribout-Jover, Pascale; Lanteigne, Anne-Marie; Jodoin, Rachel; Cluff, Christopher; Brichard, Vincent; Palmantier, Rémi; Pilorget, Anthony; Larocque, Daniel; Rivest, Serge

    2013-01-01

    Alzheimer’s disease (AD) is the most common cause of dementia worldwide. The pathogenesis of this neurodegenerative disease, currently without curative treatment, is associated with the accumulation of amyloid β (Aβ) in brain parenchyma and cerebral vasculature. AD patients are unable to clear this toxic peptide, leading to Aβ accumulation in their brains and, presumably, the pathology associated with this devastating disease. Compounds that stimulate the immune system to clear Aβ may therefore have great therapeutic potential in AD patients. Monophosphoryl lipid A (MPL) is an LPS-derived Toll-like receptor 4 agonist that exhibits unique immunomodulatory properties at doses that are nonpyrogenic. We show here that repeated systemic injections of MPL, but not LPS, significantly improved AD-related pathology in APPswe/PS1 mice. MPL treatment led to a significant reduction in Aβ load in the brain of these mice, as well as enhanced cognitive function. MPL induced a potent phagocytic response by microglia while triggering a moderate inflammatory reaction. Our data suggest that the Toll-like receptor 4 agonist MPL may be a treatment for AD. PMID:23322736

  9. Coevolution of the Toll-Like Receptor 4 Complex with Calgranulins and Lipopolysaccharide

    PubMed Central

    Loes, Andrea N.; Bridgham, Jamie T.; Harms, Michael J.

    2018-01-01

    Toll-like receptor 4 (TLR4) induces inflammation in response to both pathogen- and host-derived molecules. Lipopolysaccharide (LPS) recognition by TLR4 has been shown to occur across the amniotes, but endogenous signaling through TLR4 has not been validated outside of placental mammals. To determine whether endogenous danger signaling is also shared across amniotes, we studied the evolution of TLR4-activation by the calgranulin proteins (S100A8, S100A9, and S100A12), a clade of host molecules that potently activate TLR4 in placental mammals. We performed phylogenetic and syntenic analysis and found MRP-126—a gene in birds and reptiles—is likely orthologous to the mammalian calgranulins. We then used an ex vivo TLR4 activation assay to establish that calgranulin pro-inflammatory activity is not specific to placental mammals, but is also exhibited by representative marsupial and sauropsid species. This activity is strongly dependent on the cofactors CD14 and MD-2 for all species studied, suggesting a conserved mode of activation across the amniotes. Ortholog complementation experiments between the calgranulins, TLR4, CD14, and MD-2 revealed extensive lineage specific-coevolution and multi-way interactions between components that are necessary for the activation of NF-κB signaling by calgranulins and LPS. Our work demonstrates that calgranulin activation of TLR4 evolved at least ~320 million years ago and has been conserved in the amniote innate immune system. PMID:29515592

  10. Toll-Like Receptors: New Players in Myocardial Ischemia/Reperfusion Injury

    PubMed Central

    Ha, Tuanzhu; Liu, Li; Kelley, Jim; Kao, Race; Williams, David

    2011-01-01

    Abstract Innate immune and inflammatory responses have been implicated in myocardial ischemia/reperfusion (I/R) injury. However, the mechanisms by which innate immunity and inflammatory response are involved in myocardial I/R have not been elucidated completely. Recent studies highlight the role of Toll-like receptors (TLRs) in the induction of innate immune and inflammatory responses. Growing evidence has demonstrated that TLRs play a critical role in myocardial I/R injury. Specifically, deficiency of TLR4 protects the myocardium from ischemic injury, whereas modulation of TLR2 induces cardioprotection against ischemic insult. Importantly, cardioprotection induced by modulation of TLRs involves activation of the phosphoinositide 3-kinase (PI3K)/Akt signaling pathway, suggesting that there is a crosstalk between TLRs and PI3K/Akt signaling pathways. In addition, TLRs also associate with other coreceptors, such as macrophage scavenger receptors in the recognition of their ligands. TLRs are also involved in the induction of angiogenesis, modulation of stem cell function, and expression of microRNA, which are currently important topic areas in myocardial I/R. Understanding how TLRs contribute to myocardial I/R injury could provide basic scientific knowledge for the development of new therapeutic approaches for the treatment and management of patients with heart attack. Antioxid. Redox Signal. 15, 1875–1893. PMID:21091074

  11. Toll-Like Receptor Signaling in Burn Wound Healing and Scarring

    PubMed Central

    D'Arpa, Peter; Leung, Kai P.

    2017-01-01

    Significance: Damage-associated molecular patterns (DAMPs) and pathogen-associated molecular patterns (PAMPs) emanate from burn-injured tissue and enter systemic circulation. Locally and systemically, they activate pattern-recognition receptors, including toll-like receptors (TLRs), to stimulate cytokine secretion, which in the severest burns typically results in extreme systemic cytokine levels, a dysfunctioning immune system, infection, impaired healing, and excessive scarring. This system-wide disruption of homeostasis can advance to life-threatening, multiorgan dysfunction syndrome. Knowledge of DAMP- and PAMP-TLR signaling may lead to treatments that ameliorate local and systemic inflammation and reduce scarring and other burn injury sequela. Recent Advances: Many PAMPs and DAMPs, the TLRs they activate, and their downstream signaling molecules have been shown to contribute to local and systemic inflammation and tissue damage following burn injury. Critical Issues: Whether TLR-pathway-targeting treatments applied at different times postburn injury might improve scarring remains an open question. The evaluation of this question requires the use of appropriate preclinical and clinical burn models carried out until after mature scar has formed. Future Directions: After TLR-pathway-targeting treatments are evaluated in porcine burn wound models and their safety is demonstrated, they can be tested in proof-of-concept clinical burn wound models. PMID:29062590

  12. Characterization and expression analysis of Toll-like receptor 3 cDNA from Atlantic salmon (Salmo salar).

    PubMed

    Vidal, R; González, R; Gil, F

    2015-06-10

    Innate pathway activation is fundamental for early anti-viral defense in fish, but currently there is insufficient understanding of how salmonid fish identify viral molecules and activate these pathways. The Toll-like receptor (TLR) is believed to play a crucial role in host defense of pathogenic microbes in the innate immune system. In the present study, the full-length cDNA of Salmo salar TLR3 (ssTLR3) was cloned. The ssTLR3 cDNA sequence was 6071 bp long, containing an open reading frame of 2754 bp and encoding 971 amino acids. The TLR group motifs, such as leucine-rich repeat (LRR) domains and Toll-interleukin-1 receptor (TIR) domains, were maintained in ssTLR3, with sixteen LRR domains and one TIR domain. In contrast to descriptions of the TLR3 in rainbow trout and the murine (TATA-less), we found a putative TATA box in the proximal promoter region 29 bp upstream of the transcription start point of ssTLR3. Multiple-sequence alignment analysis of the ssTLR3 protein-coding sequence with other known TLR3 sequences showed the sequence to be conserved among all species analyzed, implying that the function of the TLR3 had been sustained throughout evolution. The ssTLR3 mRNA expression patterns were measured using real-time PCR. The results revealed that TLR3 is widely expressed in various healthy tissues. Individuals challenged with infectious pancreatic necrosis virus and immunostimulated with polyinosinic:polycytidylic acid exhibited increased expression of TLR3 at the mRNA level, indicating that ssTLR3 may be involved in pathogen recognition in the early innate immune system.

  13. High glucose induces inflammatory cytokine through protein kinase C-induced toll-like receptor 2 pathway in gingival fibroblasts

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Jiang, Shao-Yun, E-mail: jiangshaoyun@yahoo.com; Wei, Cong-Cong; Shang, Ting-Ting

    2012-10-26

    Highlights: Black-Right-Pointing-Pointer High glucose significantly induced TLR2 expression in gingival fibroblasts. Black-Right-Pointing-Pointer High glucose increased NF-{kappa}B p65 nuclear activity, IL-1{beta} and TNF-{alpha} levels. Black-Right-Pointing-Pointer PKC-{alpha}/{delta}-TLR2 pathway is involved in periodontal inflammation under high glucose. -- Abstract: Toll-like receptors (TLRs) play a key role in innate immune response and inflammation, especially in periodontitis. Meanwhile, hyperglycemia can induce inflammation in diabetes complications. However, the activity of TLRs in periodontitis complicated with hyperglycemia is still unclear. In the present study, high glucose (25 mmol/l) significantly induced TLR2 expression in gingival fibroblasts (p < 0.05). Also, high glucose increased nuclear factor kappa B (NF-{kappa}B)more » p65 nuclear activity, tumor necrosis factor-{alpha} (TNF-{alpha}) and interleukin-l{beta} (IL-1{beta}) levels. Protein kinase C (PKC)-{alpha} and {delta} knockdown with siRNA significantly decreased TLR2 and NF-{kappa}B p65 expression (p < 0.05), whereas inhibition of PKC-{beta} had no effect on TLR2 and NF-{kappa}B p65 under high glucose (p < 0.05). Additional studies revealed that TLR2 knockdown significantly abrogated high-glucose-induced NF-{kappa}B expression and inflammatory cytokine secretion. Collectively, these data suggest that high glucose stimulates TNF-{alpha} and IL-1{beta} secretion via inducing TLR2 through PKC-{alpha} and PKC-{delta} in human gingival fibroblasts.« less

  14. Identification and functional characterization of Toll-like receptor 13 from orange-spotted grouper (Epinephelus coioides).

    PubMed

    Liang, Yaosi; Ding, Xu; Yu, Xue; Wang, Yu; Zhou, Ying; He, Jianan; Shi, Yu; Zhang, Yong; Lin, Haoran; Lu, Danqi

    2018-03-01

    Toll-like receptors (TLRs) are one of the most important innate immune receptors, which recognize various pathogen-associated molecular patterns and activate the downstream immune response. Mouse TLR13 has been found to recognize a highly conserved sequence from bacterial or viral RNA and activate the myeloid differentiation primary response gene 88-dependent signaling response. The function of teleost tlr13 is still not fully understood, especially its relationship with bacterial RNA. In our study, we identified and characterized a tlr13 from Epinephelus coioides (orange-spotted grouper). The full-length cDNA of Eco. tlr13 contained a 2844 bp open reading frame, encoding 947 amino acids. The polypeptide was constitutive of a signal peptide, 13 leucine-rich repeats domains, a C-terminal leucine-rich repeats, a transmembrane domain and a conserved Toll/interleukin (IL)-1 receptor domain, indicating that Eco. Tlr13 exhibited a typical TLR structure. Multiple alignments showed that the Toll/IL-1 receptor domain of Eco. Tlr13 was identical with other homologues, and the phylogenetic tree suggested that Eco. Tlr13 was clustered with other TLR13s and had the closest relationship with predicted Lates calcarifer (sea bass) Tlr13. Subcellular localization analysis revealed that Eco. Tlr13 colocalized with the endoplasmic reticulum and early endosome. Moreover, Eco. tlr13 was broadly observed in all tested tissues with the relatively high expressions in the brain and immune-related tissues. After challenged with 19-mer Staphylococcus aureus 23S ribosomal RNA-derived oligoribonucleotide (ORN Sa19), the expression of Eco. tlr13 was significantly up-regulated in grouper spleen cells. Also, the luciferase assay further revealed that with the overexpression of Eco. Tlr13 in human embryonic kidney 293T cells, ORN Sa19 activated the promoter activity of interferon-β in a dose-dependent pattern. These results indicate that Eco. tlr13 may involve in the recognition of bacterial RNA

  15. Activation of Toll-like receptors nucleates assembly of the MyDDosome signaling hub.

    PubMed

    Latty, Sarah Louise; Sakai, Jiro; Hopkins, Lee; Verstak, Brett; Paramo, Teresa; Berglund, Nils A; Cammorota, Eugenia; Cicuta, Pietro; Gay, Nicholas J; Bond, Peter J; Klenerman, David; Bryant, Clare E

    2018-01-24

    Infection and tissue damage induces assembly of supramolecular organizing centres (SMOCs)), such as the Toll-like receptor (TLR) MyDDosome, to co-ordinate inflammatory signaling. SMOC assembly is thought to drive digital all-or-none responses, yet TLR activation by diverse microbes induces anything from mild to severe inflammation. Using single-molecule imaging of TLR4-MyDDosome signaling in living macrophages, we find that MyDDosomes assemble within minutes of TLR4 stimulation. TLR4/MD2 activation leads only to formation of TLR4/MD2 heterotetramers, but not oligomers, suggesting a stoichiometric mismatch between activated receptors and MyDDosomes. The strength of TLR4 signalling depends not only on the number and size of MyDDosomes formed but also how quickly these structures assemble. Activated TLR4, therefore, acts transiently nucleating assembly of MyDDosomes, a process that is uncoupled from receptor activation. These data explain how the oncogenic mutation of MyD88 (L265P) assembles MyDDosomes in the absence of receptor activation to cause constitutive activation of pro-survival NF-κB signalling. © 2018, Latty et al.

  16. Toll-Like Receptor 4 in Paraventricular Nucleus Mediates Visceral Hypersensitivity Induced by Maternal Separation

    PubMed Central

    Tang, Hui-Li; Zhang, Gongliang; Ji, Ning-Ning; Du, Lei; Chen, Bin-Bin; Hua, Rong; Zhang, Yong-Mei

    2017-01-01

    Neonatal maternal separation (MS) is a major early life stress that increases the risk of emotional disorders, visceral pain perception and other brain dysfunction. Elevation of toll-like receptor 4 (TLR4) signaling in the paraventricular nucleus (PVN) precipitates early life colorectal distension (CRD)-induced visceral hypersensitivity and pain in adulthood. The present study aimed to investigate the role of TLR4 signaling in the pathogenesis of postnatal MS-induced visceral hypersensitivity and pain during adulthood. The TLR4 gene was selectively knocked out in C57BL/10ScSn mice (Tlr4-/-). MS was developed by housing the offspring alone for 6 h daily from postnatal day 2 to day 15. Visceral hypersensitivity and pain were assessed in adulthood. Tlr4+/+, but not Tlr4-/-, mice that had experienced neonatal MS showed chronic visceral hypersensitivity and pain. TLR4 immunoreactivity was observed predominately in microglia in the PVN, and MS was associated with an increase in the expression of protein and/or mRNA levels of TLR4, corticotropin-releasing factor (CRF), CRF receptor 1 (CRFR1), tumor necrosis factor-α, and interleukin-1β in Tlr4+/+ mice. These alterations were not observed in Tlr4-/- mice. Local administration of lipopolysaccharide, a TLR4 agonist, into the lateral cerebral ventricle elicited visceral hypersensitivity and TLR4 mRNA expression in the PVN, which could be prevented by NBI-35965, an antagonist to CRFR1. The present results indicate that neonatal MS induces a sensitization and upregulation of microglial TLR4 signaling activity, which facilitates the neighboring CRF neuronal activity and, eventually, precipitates visceral hypersensitivity in adulthood. Highlights (1)Neonatal MS does not induce chronic visceral hypersensitivity and pain in Tlr4-/- mice.(2)Neonatal MS increases the expression of TLR4 mRNA, CRF protein and mRNA, CRFR1 protein, TNF-α protein, and IL-1β protein in Tlr4+/+ mice.(3)TLR4 agonist LPS (i.c.v.) elicits visceral

  17. Interleukin-1 receptor-associated kinase-1 plays an essential role for Toll-like receptor (TLR)7- and TLR9-mediated interferon-α induction

    PubMed Central

    Uematsu, Satoshi; Sato, Shintaro; Yamamoto, Masahiro; Hirotani, Tomonori; Kato, Hiroki; Takeshita, Fumihiko; Matsuda, Michiyuki; Coban, Cevayir; Ishii, Ken J.; Kawai, Taro; Takeuchi, Osamu; Akira, Shizuo

    2005-01-01

    Toll-like receptors (TLRs) recognize microbial pathogens and trigger innate immune responses. Among TLR family members, TLR7, TLR8, and TLR9 induce interferon (IFN)-α in plasmacytoid dendritic cells (pDCs). This induction requires the formation of a complex consisting of the adaptor MyD88, tumor necrosis factor (TNF) receptor-associated factor 6 (TRAF6) and IFN regulatory factor (IRF) 7. Here we show an essential role of IL-1 receptor-associated kinase (IRAK)-1 in TLR7- and TLR9-mediated IRF7 signaling pathway. IRAK-1 directly bound and phosphorylated IRF7 in vitro. The kinase activity of IRAK-1 was necessary for transcriptional activation of IRF7. TLR7- and TLR9-mediated IFN-α production was abolished in Irak-1–deficient mice, whereas inflammatory cytokine production was not impaired. Despite normal activation of NF-κB and mitogen-activated protein kinases, IRF7 was not activated by a TLR9 ligand in Irak-1–deficient pDCs. These results indicated that IRAK-1 is a specific regulator for TLR7- and TLR9-mediated IFN-α induction in pDCs. PMID:15767370

  18. A tryptophan-rich motif in the human parainfluenza virus type 2 V protein is critical for the blockade of toll-like receptor 7 (TLR7)- and TLR9-dependent signaling.

    PubMed

    Kitagawa, Yoshinori; Yamaguchi, Mayu; Zhou, Min; Komatsu, Takayuki; Nishio, Machiko; Sugiyama, Tsuyoshi; Takeuchi, Kenji; Itoh, Masae; Gotoh, Bin

    2011-05-01

    Plasmacytoid dendritic cells (pDCs) do not produce alpha interferon (IFN-α) unless viruses cause a systemic infection or overcome the first-line defense provided by conventional DCs and macrophages. We show here that even paramyxoviruses, whose infections are restricted to the respiratory tract, have a V protein able to prevent Toll-like receptor 7 (TLR7)- and TLR9-dependent IFN-α induction specific to pDCs. Mutational analysis of human parainfluenza virus type 2 demonstrates that the second Trp residue of the Trp-rich motif (Trp-X(3)-Trp-X(9)-Trp) in the C-terminal domain unique to V, a determinant for IRF7 binding, is critical for the blockade of TLR7/9-dependent signaling.

  19. Gut microbial products regulate murine gastrointestinal motility via Toll-like Receptor 4 signaling

    PubMed Central

    Anitha, Mallappa; Vijay-Kumar, Matam; Sitaraman, Shanthi V.; Gewirtz, Andrew T.; Srinivasan, Shanthi

    2012-01-01

    Background & Aims Altered gastrointestinal motility is associated with significant morbidity and health care costs. Toll-like receptors regulate intestinal homeostasis. We examined the roles of Toll-like receptor (TLR)4 signaling in survival of enteric neurons and gastrointestinal motility. Methods We assessed changes in intestinal motility by assessing stool frequency, bead expulsion, and isometric muscle recordings of colonic longitudinal muscle strips from mice that do not express TLR4 (Tlr4Lps-d or TLR4−/−) or Myd88 (Myd88−/−), in wild-type germ-free mice or wild-type mice depleted of the microbiota, and in mice with neural crest-specific deletion of Myd88 (Wnt1Cre+/−/Myd88fl/fl). We studied the effects of the TLR4 agonist lipopolysaccharide (LPS) on survival of cultured, immortalized fetal enteric neurons (IM-FEN) and enteric neuronal cells isolated from wild-type and Tlr4Lps-d mice at embryonic day 13.5. Results There was a significant delay in gastrointestinal motility and reduced numbers of nitrergic neurons in TLR4Lps-d, TLR4−/−, and Myd88−/− mice, compared with wild-type mice. A similar phenotype was observed in germ-free mice, mice depleted of intestinal microbiota, and Wnt1Cre+/−/Myd88fl/fl mice. Incubation of enteric neuronal cells with LPS led to activation of the transcription factor NF-κB and increased cell survival. Conclusions Interactions between enteric neurons and microbes increases neuron survival and gastrointestinal motility in mice. LPS activation of TLR4 and NF-κB appears to promote survival of enteric neurons. Factors that regulate TLR4 signaling by neurons might be developed to alter gastrointestinal motility. PMID:22732731

  20. Upregulation of toll-like receptors in chronic enteropathies in dogs.

    PubMed

    Burgener, I A; König, A; Allenspach, K; Sauter, S N; Boisclair, J; Doherr, M G; Jungi, T W

    2008-01-01

    Inflammatory bowel disease (IBD) is thought to result from a dysregulated interaction between the host immune system and commensal microflora. Toll-like receptors (TLRs) recognize microbe-associated molecular patterns (MAMPs), but their role in enteropathies in dogs is unknown. That there is a dysregulation of TLRs recognizing bacterial MAMPs in dogs with IBD. Sixteen healthy beagles and 12 dogs with steroid-treated (ST) and 23 dogs with food-responsive (FR) diarrhea. Prospective, observational study. mRNA expression of canine TLR2, 4, and 9 was evaluated by quantitative real-time RT-PCR in duodenal and colonic biopsies obtained before and after standard therapy. Samples from control dogs were taken at necropsy, with additional biopsies of stomach, jejunum, ileum, and mesenteric lymph node in 6 dogs. There were significant differences (P< or = .017) in expression of TLR2, 4, and 9 between the 6 sampled locations in healthy control dogs (lymph node > small intestine > or = colon). Before therapy, ST expressed more mRNA than control dogs for all 3 receptors (P < .05). There were no significant differences between pretreatment and posttreatment values, even though 32/35 dogs improved clinically. No associations were found when comparing receptor mRNA expression with either histology or clinical activity scores. Bacteria-responsive TLR2, 4, and 9 are upregulated in duodenal and colonic mucosa in IBD. This might lead to increased inflammation through interaction with the commensal flora. The absence of significant changes after therapy despite clinical improvement might point toward the existence of a genetic predisposition to IBD as described in human IBD.

  1. Toll-like receptors 3, 7, and 9 in Juvenile nasopharyngeal angiofibroma.

    PubMed

    Renkonen, Suvi; Cardell, Lars-Olaf; Mattila, Petri; Lundberg, Marie; Haglund, Caj; Hagström, Jaana; Mäkitie, Antti A

    2015-05-01

    Juvenile nasopharyngeal angiofibroma (JNA) is a rare, benign tumor affecting adolescent males. The etiology of JNA as well as the causes determining the variable growth patterns of individual tumors remains unknown. Toll-like receptors (TLRs) are part of the innate immune response to microbes; by recognition of distinct features, they link to induction of pro-inflammatory signaling pathways. We immunostained TLR 3, 7, and 9 in 27 JNA specimens of patients treated at the Helsinki University Central Hospital, Helsinki, Finland, during the years 1970-2009. TLR 3, 7, and 9 expressions were found in stromal and endothelial cells of JNA, and their expression levels varied from negative to very strong positive. TLR 3 expression was found to have a significant correlation with the clinical stage of JNA. The present results propose a putative role of TLRs in the growth process of JNA. © 2015 APMIS. Published by John Wiley & Sons Ltd.

  2. Sequence variants of Toll-like receptor 4 and susceptibility to prostate cancer.

    PubMed

    Chen, Yen-Ching; Giovannucci, Edward; Lazarus, Ross; Kraft, Peter; Ketkar, Shamika; Hunter, David J

    2005-12-15

    Chronic inflammation has been hypothesized to be a risk factor for prostate cancer. The Toll-like receptor 4 (TLR4) presents the bacterial lipopolysaccharide (LPS), which interacts with ligand-binding protein and CD14 (LPS receptor) and activates expression of inflammatory genes through nuclear factor-kappaB and mitogen-activated protein kinase signaling. A previous case-control study found a modest association of a polymorphism in the TLR4 gene [11381G/C, GG versus GC/CC: odds ratio (OR), 1.26] with risk of prostate cancer. We assessed if sequence variants of TLR4 were associated with the risk of prostate cancer. In a nested case-control design within the Health Professionals Follow-up Study, we identified 700 participants with prostate cancer diagnosed after they had provided a blood specimen in 1993 and before January 2000. Controls were 700 age-matched men without prostate cancer who had had a prostate-specific antigen test after providing a blood specimen. We genotyped 16 common (>5%) single nucleotide polymorphisms (SNP) discovered in a resequencing study spanning TLR4 to test for association between sequence variation in TLR4 and prostate cancer. Homozygosity for the variant alleles of eight SNPs was associated with a statistically significantly lower risk of prostate cancer (TLR4_1893, TLR4_2032, TLR4_2437, TLR4_7764, TLR4_11912, TLR4_16649, TLR4_17050, and TLR4_17923), but the TLR4_15844 polymorphism corresponding to 11381G/C was not associated with prostate cancer (GG versus CG/CC: OR, 1.01; 95% confidence interval, 0.79-1.29). Six common haplotypes (cumulative frequency, 81%) were observed; the global test for association between haplotypes and prostate cancer was statistically significant (chi(2) = 14.8 on 6 degrees of freedom; P = 0.02). Two common haplotypes were statistically significantly associated with altered risk of prostate cancer. Inherited polymorphisms of the innate immune gene TLR4 are associated with risk of prostate cancer.

  3. Identification of Substituted Pyrimido[5,4-b]indoles as Selective Toll-Like Receptor 4 Ligands

    PubMed Central

    2013-01-01

    A cell-based high-throughput screen to identify small molecular weight stimulators of the innate immune system revealed substituted pyrimido[5,4-b]indoles as potent NFκB activators. The most potent hit compound selectively stimulated Toll-like receptor 4 (TLR4) in human and mouse cells. Synthetic modifications of the pyrimido[5,4-b]indole scaffold at the carboxamide, N-3, and N-5 positions revealed differential TLR4 dependent production of NFκB and type I interferon associated cytokines, IL-6 and interferon γ-induced protein 10 (IP-10) respectively. Specifically, a subset of compounds bearing phenyl and substituted phenyl carboxamides induced lower IL-6 release while maintaining higher IP-10 production, skewing toward the type I interferon pathway. Substitution at N-5 with short alkyl substituents reduced the cytotoxicity of the leading hit compound. Computational studies supported that active compounds appeared to bind primarily to MD-2 in the TLR4/MD-2 complex. These small molecules, which stimulate innate immune cells with minimal toxicity, could potentially be used as adjuvants or immune modulators. PMID:23656327

  4. Toll-like receptors 2 and 4 exert opposite effects on the contractile response induced by serotonin in mouse colon: role of serotonin receptors.

    PubMed

    Forcén, R; Latorre, E; Pardo, J; Alcalde, A I; Murillo, M D; Grasa, L

    2016-08-01

    What is the central question of this study? The action of Toll-like receptors (TLRs) 2 and 4 on the motor response to serotonin in mouse colon has not previously been reported. What is the main finding and its importance? Toll-like receptors 2 and 4 modulate the serotonin-induced contractile response in mouse colon by modifying the expression of serotonin (5-HT) receptors. Alterations in 5-HT2A and 5-HT2C receptors explain the increase of the response to serotonin in TLR2(-/-) mice. Alterations in 5-HT2C and 5-HT4 receptors explain the suppression of the response to serotonin in TLR4(-/-) mice. The microbiota, through Toll-like receptors (TLRs), may regulate gastrointestinal motility by activating neuroendocrine mechanisms. We evaluated the influence of TLR2 and TLR4 in spontaneous contractions and in the serotonin (5-HT)-induced motor response in mouse colon, and assessed the 5-HT receptors involved. Muscle contractility studies to evaluate the intestinal spontaneous motility and the response to 5-HT were performed in the colon from wild-type (WT), TLR2(-/-) , TLR4(-/-) and TLR2/4 double knockout (DKO) mice. The 5-HT receptor mRNA expression was determined by real-time PCR. The amplitude and frequency of the spontaneous contractions of the colon were smaller in TLR4(-/-) and TLR2/4 DKO mice with respect to WT mice. In WT, TLR2(-/-) and TLR2/4 DKO mice, 100 μm 5-HT evoked a contractile response. The contractile response induced by 5-HT was significantly higher in TLR2(-/-) than in WT mice. In TLR4(-/-) mice, 5-HT did not evoke any contractile response. The mRNA expression of 5-HT2A was increased in TLR2(-/-) and TLR2/4 DKO mice. The 5-HT2C and 5-HT4 mRNA expressions were increased in TLR4(-/-) and TLR2/4 DKO mice. The 5-HT2C mRNA expression was diminished in TLR2(-/-) mice. The 5-HT3 mRNA expression was increased in TLR2(-/-) , TLR4(-/-) and TLR2/4 DKO mice. The 5-HT7 mRNA expression was diminished in TLR2/4 DKO mice. In WT, TLR2(-/-) and TLR2/4 DKO mice, 5-HT2

  5. Downregulation of toll-like receptor-mediated signalling pathways in oral lichen planus.

    PubMed

    Sinon, Suraya H; Rich, Alison M; Parachuru, Venkata P B; Firth, Fiona A; Milne, Trudy; Seymour, Gregory J

    2016-01-01

    The objective of this study was to investigate the expression of Toll-like receptors (TLR) and TLR-associated signalling pathway genes in oral lichen planus (OLP). Initially, immunohistochemistry was used to determine TLR expression in 12 formalin-fixed archival OLP tissues with 12 non-specifically inflamed oral tissues as controls. RNA was isolated from further fresh samples of OLP and non-specifically inflamed oral tissue controls (n = 6 for both groups) and used in qRT(2)-PCR focused arrays to determine the expression of TLRs and associated signalling pathway genes. Genes with a statistical significance of ±two-fold regulation (FR) and a P-value < 0.05 were considered as significantly regulated. Significantly more TLR4(+) cells were present in the inflammatory infiltrate in OLP compared with the control tissues (P < 0.05). There was no statistically significant difference in the numbers of TLR2(+) and TLR8(+) cells between the groups. TLR3 was significantly downregulated in OLP (P < 0.01). TLR8 was upregulated in OLP, but the difference between the groups was not statistically significant. The TLR-mediated signalling-associated protein genes MyD88 and TIRAP were significantly downregulated (P < 0.01 and P < 0.05), as were IRAK1 (P < 0.05), MAPK8 (P < 0.01), MAP3K1 (P < 0.05), MAP4K4 (P < 0.05), REL (P < 0.01) and RELA (P < 0.01). Stress proteins HMGB1 and the heat shock protein D1 were significantly downregulated in OLP (P < 0.01). These findings suggest a downregulation of TLR-mediated signalling pathways in OLP lesions. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  6. Barrier-protective function of intestinal epithelial Toll-like receptor 2.

    PubMed

    Cario, E

    2008-11-01

    The intestinal epithelial cell (IEC) barrier plays an important role in maintaining mucosal immune homeostasis. Dysregulated IEC barrier function appears to trigger and perpetuate inflammation in inflammatory bowel diseases (IBD). Novel risk variants in the Toll-like receptor 2 (TLR2) gene have previously been associated with a more severe disease phenotype in a subgroup of IBD patients. Recent studies have provided important insights of the commensal and host defense mechanisms to maintain functional barrier integrity of the intestinal epithelium through TLR2. Deficient TLR2 signaling may imbalance commensal-dependent intestinal epithelial barrier defense, facilitating mucosal injury and leading to increased susceptibility of colitis. Treatment with a synthetic TLR2 ligand significantly suppresses mucosal inflammation by efficiently protecting tight junction-associated integrity of the intestinal epithelium in vivo. These beneficial effects may be supplemented by TLR2-induced anti-inflammatory immune responses (such as interleukin-10 production) in lamina propria mononuclear cells. Thus, cell-specific TLR2 targeting may offer a novel therapeutic approach to human IBD therapy by protecting IEC barrier function.

  7. Serum Amyloid A Promotes E-Selectin Expression via Toll-Like Receptor 2 in Human Aortic Endothelial Cells.

    PubMed

    Nishida, Eisaku; Aino, Makoto; Kobayashi, Shu-Ichiro; Okada, Kosuke; Ohno, Tasuku; Kikuchi, Takeshi; Hayashi, Jun-Ichiro; Yamamoto, Genta; Hasegawa, Yoshiaki; Mitani, Akio

    2016-01-01

    Periodontitis is a chronic inflammatory disease that affects the periodontium. Recent studies suggest an association between periodontal and cardiovascular diseases. However, the detailed molecular mechanism is unknown. A previous study has demonstrated that experimental periodontitis induces serum amyloid A (SAA) in the liver and peripheral blood of ApoE-deficient mice as an atherosclerosis model. SAA is an acute-phase protein that affects systemic inflammation. The aim of this study is to investigate the atherosclerosis-onset mechanism using human aortic endothelial cells (HAECs) stimulated by SAA in vitro . Atherosclerosis PCR array and qPCR analyses showed upregulation of adhesion molecules such as intercellular adhesion molecule-1, vascular cell adhesion molecule-1, and E-selectin in HAECs upon SAA stimulation. In addition, the results demonstrated that Toll-like receptor, TLR2, could serve as an important receptor of SAA in HAECs. Furthermore, small interfering RNA (siRNA) against TLR2 inhibited the upregulation of adhesion molecules in HAECs stimulated by SAA. Our results suggest that SAA stimulates the expression of adhesion molecules via TLR2. SAA could be an important molecule for atherosclerosis induced by periodontal disease.

  8. Serum Amyloid A Promotes E-Selectin Expression via Toll-Like Receptor 2 in Human Aortic Endothelial Cells

    PubMed Central

    2016-01-01

    Periodontitis is a chronic inflammatory disease that affects the periodontium. Recent studies suggest an association between periodontal and cardiovascular diseases. However, the detailed molecular mechanism is unknown. A previous study has demonstrated that experimental periodontitis induces serum amyloid A (SAA) in the liver and peripheral blood of ApoE-deficient mice as an atherosclerosis model. SAA is an acute-phase protein that affects systemic inflammation. The aim of this study is to investigate the atherosclerosis-onset mechanism using human aortic endothelial cells (HAECs) stimulated by SAA in vitro. Atherosclerosis PCR array and qPCR analyses showed upregulation of adhesion molecules such as intercellular adhesion molecule-1, vascular cell adhesion molecule-1, and E-selectin in HAECs upon SAA stimulation. In addition, the results demonstrated that Toll-like receptor, TLR2, could serve as an important receptor of SAA in HAECs. Furthermore, small interfering RNA (siRNA) against TLR2 inhibited the upregulation of adhesion molecules in HAECs stimulated by SAA. Our results suggest that SAA stimulates the expression of adhesion molecules via TLR2. SAA could be an important molecule for atherosclerosis induced by periodontal disease. PMID:27799725

  9. Bacterial interactions with cells of the intestinal mucosa: Toll-like receptors and NOD2.

    PubMed

    Cario, E

    2005-08-01

    Toll-like receptors (TLR) and NOD2 are emerging as key mediators of innate host defence in the intestinal mucosa, crucially involved in maintaining mucosal as well as commensal homeostasis. Recent observations suggest new (patho-) physiological mechanisms of how functional versus dysfunctional TLRx/NOD2 pathways may oppose or favour inflammatory bowel disease (IBD). In health, TLRx signalling protects the intestinal epithelial barrier and confers commensal tolerance whereas NOD2 signalling exerts antimicrobial activity and prevents pathogenic invasion. In disease, aberrant TLRx and/or NOD2 signalling may stimulate diverse inflammatory responses leading to acute and chronic intestinal inflammation with many different clinical phenotypes.

  10. Toll-like receptor activation by helminths or helminth products to alleviate inflammatory bowel disease.

    PubMed

    Sun, ShuMin; Wang, XueLin; Wu, XiuPing; Zhao, Ying; Wang, Feng; Liu, XiaoLei; Song, Yanxia; Wu, ZhiLiang; Liu, MingYuan

    2011-09-27

    Helminth infection may modulate the expression of Toll like receptors (TLR) in dendritic cells (DCs) and modify the responsiveness of DCs to TLR ligands. This may regulate aberrant intestinal inflammation in humans with helminthes and may thus help alleviate inflammation associated with human inflammatory bowel disease (IBD). Epidemiological and experimental data provide further evidence that reducing helminth infections increases the incidence rate of such autoimmune diseases. Fine control of inflammation in the TLR pathway is highly desirable for effective host defense. Thus, the use of antagonists of TLR-signaling and agonists of their negative regulators from helminths or helminth products should be considered for the treatment of IBD.

  11. Toll-like receptor activation by helminths or helminth products to alleviate inflammatory bowel disease

    PubMed Central

    2011-01-01

    Helminth infection may modulate the expression of Toll like receptors (TLR) in dendritic cells (DCs) and modify the responsiveness of DCs to TLR ligands. This may regulate aberrant intestinal inflammation in humans with helminthes and may thus help alleviate inflammation associated with human inflammatory bowel disease (IBD). Epidemiological and experimental data provide further evidence that reducing helminth infections increases the incidence rate of such autoimmune diseases. Fine control of inflammation in the TLR pathway is highly desirable for effective host defense. Thus, the use of antagonists of TLR-signaling and agonists of their negative regulators from helminths or helminth products should be considered for the treatment of IBD. PMID:21943110

  12. Taking a Toll on human disease: Toll-like receptor 4 agonists as vaccine adjuvants and monotherapeutic agents.

    PubMed

    Baldridge, Jory R; McGowan, Patrick; Evans, Jay T; Cluff, Christopher; Mossman, Sally; Johnson, David; Persing, David

    2004-07-01

    Toll-like receptor (TLR) agonists are being developed for use as vaccine adjuvants and as stand-alone immunomodulators because of their ability to stimulate innate and adaptive immune responses. Among the most thoroughly studied TLR agonists are the lipid A molecules that target the TLR4 complex. One promising candidate, monophosphoryl lipid A, which is a derivative of lipid A from Salmonella minnesota, has proven to be safe and effective as a vaccine adjuvant in > 120,000 human doses. A new class of synthetic lipid A mimetics, the aminoalkyl glucosaminide 4-phosphates (AGPs), have been engineered specifically to target human TLR4 and are showing promise as vaccine adjuvants and as monotherapeutic agents capable of eliciting nonspecific protection against a wide range of infectious pathogens. In this review, the authors provide an update of the preclinical and clinical experiences with the TLR4 agonists, MPL (Corixa Corporation) adjuvant and the AGPs.

  13. The structural basis for endotoxin-induced allosteric regulation of the Toll-like receptor 4 (TLR4) innate immune receptor.

    PubMed

    Paramo, Teresa; Piggot, Thomas J; Bryant, Clare E; Bond, Peter J

    2013-12-20

    As part of the innate immune system, Toll-like receptor 4 (TLR4) recognizes bacterial cell surface lipopolysaccharide (LPS) by forming a complex with a lipid-binding co-receptor, MD-2. In the presence of agonist, TLR4·MD-2 dimerizes to form an active receptor complex, leading to initiation of intracellular inflammatory signals. TLR4 is of great biomedical interest, but its pharmacological manipulation is complicated because even subtle variations in the structure of LPS can profoundly impact the resultant immunological response. Here, we use atomically detailed molecular simulations to gain insights into the nature of the molecular signaling mechanism. We first demonstrate that MD-2 is extraordinarily flexible. The "clamshell-like" motions of its β-cup fold enable it to sensitively match the volume of its hydrophobic cavity to the size and shape of the bound lipid moiety. We show that MD-2 allosterically transmits this conformational plasticity, in a ligand-dependent manner, to a phenylalanine residue (Phe-126) at the cavity mouth previously implicated in TLR4 activation. Remarkably, within the receptor complex, we observe spontaneous transitions between active and inactive signaling states of Phe-126, and we confirm that Phe-126 is indeed the "molecular switch" in endotoxic signaling.

  14. Sperm protection in the male reproductive tract by Toll-like receptors.

    PubMed

    Saeidi, S; Shapouri, F; Amirchaghmaghi, E; Hoseinifar, H; Sabbaghian, M; Sadighi Gilani, M A; Pacey, A A; Aflatoonian, R

    2014-09-01

    Sperm function can be affected by infection. Our understanding of innate immune system molecular mechanisms has been expanded, by the discovery of 'Toll-like receptors' (TLRs). It seems that these receptors could play a critical role in the protection of spermatozoa. This study seeks to examine the presence and distribution of TLRs in different parts of the human male reproductive tract and spermatozoa. So, TLR gene expression was examined by RT-PCR. Quantitative real-time PCR (Q-PCR) analysis used to compare the expression of TLRs in all sections of the male reproductive tract and TLRs 2, 3 and 4 in testicular sperm extraction (TESE) samples, which contained spermatozoa (TESE+) and those that did not (TESE-). Results showed that all TLR genes were expressed in different parts of the human male reproductive tract and spermatozoa. Moreover, Q-PCR indicated that the relative expression of TLRs did not significantly change in different parts of the male reproductive tract but this technique has shown only relative TLR2 expression in TESE- is lower than TESE+ samples. It could be concluded that TLRs may provide a broad spectrum of protection from infection in the male reproductive tract. Furthermore, TLRs may influence on the developmental process during spermatogenesis. © 2013 Blackwell Verlag GmbH.

  15. Secretion of Hepatitis C Virus Replication Intermediates Reduces Activation of Toll-Like Receptor 3 in Hepatocytes.

    PubMed

    Grünvogel, Oliver; Colasanti, Ombretta; Lee, Ji-Young; Klöss, Volker; Belouzard, Sandrine; Reustle, Anna; Esser-Nobis, Katharina; Hesebeck-Brinckmann, Jasper; Mutz, Pascal; Hoffmann, Katrin; Mehrabi, Arianeb; Koschny, Ronald; Vondran, Florian W R; Gotthardt, Daniel; Schnitzler, Paul; Neumann-Haefelin, Christoph; Thimme, Robert; Binder, Marco; Bartenschlager, Ralf; Dubuisson, Jean; Dalpke, Alexander H; Lohmann, Volker

    2018-06-01

    Hepatitis C virus (HCV) infections most often result in chronic outcomes, although the virus constantly produces replication intermediates, in particular double-stranded RNA (dsRNA), representing potent inducers of innate immunity. We aimed to characterize the fate of HCV dsRNA in hepatocyte cultures to identify mechanisms contributing to viral persistence in presence of an active innate immune response. We analyzed hepatocyte-based culture models for HCV for induction of innate immunity, secretion of virus positive- or negative-strand RNA, and viral replication using different quantification methods and microscopy techniques. Expression of pattern recognition receptors was reconstituted in hepatoma cells by lentiviral transduction. HCV-infected cells secrete substantial amounts of virus positive- and negative-strand RNAs in extracellular vesicles (EVs), toward the apical and basolateral domain of hepatocytes. Secretion of negative-strand RNA was independent from virus production, and viral RNA secreted in EVs contained higher relative amounts of negative-strands, indicating that mostly virus dsRNA is released. A substantial part of viral replication complexes and dsRNA was found in the endosomal compartment and multivesicular bodies, indicating that secretion of HCV replication intermediates is mediated by the exosomal pathway. Block of vesicle release in HCV-positive cells increased intracellular dsRNA levels and increased activation of toll-like receptor 3, inhibiting HCV replication. Using hepatocyte-based culture models for HCV, we found a portion of HCV dsRNA intermediates to be released from infected cells in EVs, which reduces activation of toll-like receptor 3. This represents a novel mechanism how HCV evades host immune responses, potentially contributing to viral persistence. Copyright © 2018 AGA Institute. Published by Elsevier Inc. All rights reserved.

  16. Modulation of Toll-like receptor signaling in innate immunity by natural products.

    PubMed

    Chen, Luxi; Yu, Jianhua

    2016-08-01

    For centuries, natural products and their derivatives have provided a rich source of compounds for the development of new immunotherapies in the treatment of human disease. Many of these compounds are currently undergoing clinical trials, particularly as anti-oxidative, anti-microbial, and anti-cancer agents. However, the function and mechanism of natural products in how they interact with our immune system has yet to be extensively explored. Natural immune modulators may provide the key to control and ultimately defeat disorders affecting the immune system. They can either up- or down-regulate the immune response with few undesired adverse effects. In this review, we summarize the recent advancements made in utilizing natural products for immunomodulation and their important molecular targets, members of the Toll-like receptor (TLR) family, in the innate immune system. Copyright © 2016 Elsevier B.V. All rights reserved.

  17. Innate immune receptor Toll-like receptor 4 signalling in neuropsychiatric diseases.

    PubMed

    García Bueno, B; Caso, J R; Madrigal, J L M; Leza, J C

    2016-05-01

    The innate immunity is a stereotyped first line of defense against pathogens and unspecified damage signals. One of main actors of innate immunity are the Toll-like receptors (TLRs), and one of the better characterized members of this family is TLR-4, that it is mainly activated by Gram-negative bacteria lipopolysaccharide. In brain, TLR-4 organizes innate immune responses against infections or cellular damage, but also possesses other physiological functions. In the last years, some evidences suggest a role of TLR-4 in stress and stress-related neuropsychiatric diseases. Peripheral and brain TLR-4 activation triggers sickness behavior, and its expression is a risk factor of depression. Some elements of the TLR-4 signaling pathway are up-regulated in peripheral samples and brain post-mortem tissue from depressed and suicidal patients. The "leaky gut" hypothesis of neuropsychiatric diseases is based on the existence of an increase of the intestinal permeability which results in bacterial translocation able to activate TLR-4. Enhanced peripheral TLR-4 expression/activity has been described in subjects diagnosed with schizophrenia, bipolar disorder and in autistic children. A role for TLR-4 in drugs abuse has been also proposed. The therapeutic potential of pharmacological/genetic modulation of TLRs signaling pathways in neuropsychiatry is promising, but a great preclinical/clinical scientific effort is still needed. Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. Mucosal interplay among commensal and pathogenic bacteria: lessons from flagellin and Toll-like receptor 5.

    PubMed

    Rumbo, Martin; Nempont, Clément; Kraehenbuhl, Jean-Pierre; Sirard, Jean-Claude

    2006-05-22

    Toll-like receptors (TLR) detect pathogen-associated molecular patterns (PAMP) and play a crucial role in triggering immunity. Due to their large surfaces in direct contact with the environment, mucosal tissues are the major sites of PAMP-TLR signalling. How innate and adaptive immunity are triggered through flagellin-TLR5 interaction is the main focus of the review. In view of recent reports on genetic polymorphism, we will summarize the impact of TLR5 on the susceptibility to mucosal infections and on various immuno-pathologies. Finally, the contribution of TLRs in the induction and maintenance of mucosal homeostasis and commensal discrimination is discussed.

  19. Neu1 Sialidase and Matrix Metalloproteinase-9 Cross-talk Is Essential for Toll-like Receptor Activation and Cellular Signaling*

    PubMed Central

    Abdulkhalek, Samar; Amith, Schammim Ray; Franchuk, Susan L.; Jayanth, Preethi; Guo, Merry; Finlay, Trisha; Gilmour, Alanna; Guzzo, Christina; Gee, Katrina; Beyaert, Rudi; Szewczuk, Myron R.

    2011-01-01

    The signaling pathways of mammalian Toll-like receptors (TLRs) are well characterized, but the precise mechanism(s) by which TLRs are activated upon ligand binding remains poorly defined. Recently, we reported a novel membrane sialidase-controlling mechanism that depends on ligand binding to its TLR to induce mammalian neuraminidase-1 (Neu1) activity, to influence receptor desialylation, and subsequently to induce TLR receptor activation and the production of nitric oxide and proinflammatory cytokines in dendritic and macrophage cells. The α-2,3-sialyl residue of TLR was identified as the specific target for hydrolysis by Neu1. Here, we report a membrane signaling paradigm initiated by endotoxin lipopolysaccharide (LPS) binding to TLR4 to potentiate G protein-coupled receptor (GPCR) signaling via membrane Gαi subunit proteins and matrix metalloproteinase-9 (MMP9) activation to induce Neu1. Central to this process is that a Neu1-MMP9 complex is bound to TLR4 on the cell surface of naive macrophage cells. Specific inhibition of MMP9 and GPCR Gαi-signaling proteins blocks LPS-induced Neu1 activity and NFκB activation. Silencing MMP9 mRNA using lentivirus MMP9 shRNA transduction or siRNA transfection of macrophage cells and MMP9 knock-out primary macrophage cells significantly reduced Neu1 activity and NFκB activation associated with LPS-treated cells. These findings uncover a molecular organizational signaling platform of a novel Neu1 and MMP9 cross-talk in alliance with TLR4 on the cell surface that is essential for ligand activation of TLRs and subsequent cellular signaling. PMID:21873432

  20. Polysaccharide of Dendrobium huoshanense activates macrophages via toll-like receptor 4-mediated signaling pathways.

    PubMed

    Xie, Song-Zi; Hao, Ran; Zha, Xue-Qiang; Pan, Li-Hua; Liu, Jian; Luo, Jian-Ping

    2016-08-01

    The present work aimed at investigating the pattern recognition receptor (PRR) and immunostimulatory mechanism of a purified Dendrobium huoshanense polysaccharide (DHP). We found that DHP could bind to the surface of macrophages and stimulate macrophages to secrete NO, TNF-α and IL-1β. To unravel the mechanism for the binding of DHP to macrophages, flow cytometry, confocal laser-scanning microscopy, affinity electrophoresis, SDS-PAGE and western blotting were employed to verify the type of PRR responsible for the recognition of DHP by RAW264.7 macrophages and peritoneal macrophages of C3H/HeN and C3H/HeJ macrophages. Results showed that toll-like receptor 4 (TLR4) was an essential receptor for macrophages to directly bind DHP. Further, the phosphorylation of ERK, JNK, Akt and p38 were observed to be time-dependently promoted by DHP, as well as the nuclear translocation of NF-κB p65. These results suggest that DHP activates macrophages via its direct binding to TLR4 to trigger TLR4 signaling pathways. Copyright © 2016 Elsevier Ltd. All rights reserved.

  1. Toll-like receptor 2-mediated peptidoglycan uptake by immature intestinal epithelial cells from apical side and exosome-associated transcellular transcytosis

    PubMed Central

    Bu, Heng-Fu; Wang, Xiao; Tang, Yi; Koti, Viola; Tan, Xiao-Di

    2015-01-01

    Peptidoglycan is a potent immune adjuvant derived from bacterial cell walls. Previous investigations suggest that intestinal epithelium may absorb peptidoglycan from the lumen. Nonetheless, how peptidoglycan is taken up and crosses intestinal epithelium remains largely unclear. Here, we first characterized peptidoglycan transport in vitro using IEC-18 and HT29-CL19A cells, which represent less mature epithelial cells in intestinal crypts. With fluorescent microscopy, we visualized internalization of dual-labeled peptidoglycan by enterocytes. Engulfed peptidoglycan was found to form a complex with peptidoglycan recognition protein-3, which may facilitate delivering peptidoglycan in vivo. Utilizing electronic microscopy, we revealed that uptake of apical peptidoglycan across intestinal epithelial monolayers was involved in phagocytosis, multivesicular body formation, and exosome secretion. We also studied transport of peptidoglycan using the transwell system. Our data indicated that apically loaded peptidoglycan was exocytosed to the basolateral compartment with exosomes by HT29-CL19A cells. The peptidoglycan-contained basolateral exosome extracts induced macrophage activation. Through gavaging mice with labeled peptidoglycan, we found that luminal peptidoglycan was taken up by columnar epithelial cells in crypts of the small intestine. Furthermore, we showed that pre-confluent immature but not post-confluent mature C2BBe1 cells engulfed peptidoglycan via a toll-like receptor 2-dependent manner. Together, our findings suggest that (1) crypt-based immature intestinal epithelial cells play an important role in transport of luminal peptidoglycan over the intestinal epithelium; and (2) luminal peptidoglycan is transcytosed across intestinal epithelia via a toll-like receptor 2-meciated phagocytosis-multivesicular body-exosome pathway. The absorbed peptidoglycan and its derivatives may facilitate maintenance of intestinal immune homeostasis. PMID:20020500

  2. Differential expression of Toll-like receptor pathway genes in chicken embryo fibroblasts from chickens resistant and susceptible to Marek’s disease

    USDA-ARS?s Scientific Manuscript database

    The Toll-like receptor (TLR) signaling pathway is one of the innate immune defense mechanisms against pathogens in vertebrates and invertebrates. However, the role of TLR in non-MHC genetic resistance or susceptibility to Marek’s disease (MD) in the chicken is yet to be elucidated. Chicken embryo fi...

  3. Toll-like receptor-mediated inhibition of Gas6 and ProS expression facilitates inflammatory cytokine production in mouse macrophages

    PubMed Central

    Deng, Tingting; Zhang, Yue; Chen, Qiaoyuan; Yan, Keqin; Han, Daishu

    2012-01-01

    Activation of Toll-like receptors (TLRs) triggers rapid inflammatory cytokine production in various cell types. The exogenous product of growth-arrest-specific gene 6 (Gas6) and Protein S (ProS) inhibit the TLR-triggered inflammatory responses through the activation of Tyro3, Axl and Mer (TAM) receptors. However, regulation of the Gas6/ProS-TAM system remains largely unknown. In the current study, mouse macrophages are shown to constitutively express Gas6 and ProS, which synergistically suppress the basal and TLR-triggered production of inflammatory cytokines, including those of tumour necrosis factor-α, interleukin-6 and interleukin-1β, by the macrophages in an autocrine manner. Notably, TLR signalling markedly decreases Gas6 and ProS expression in macrophages through the activation of the nuclear factor-κB. Further, the down-regulation of Gas6 and ProS by TLR signalling facilitates the TLR-mediated inflammatory cytokine production in mouse macrophages. These results describe a self-regulatory mechanism of TLR signalling through the suppression of Gas6 and ProS expression. PMID:22043818

  4. Mycobacterium leprae Activates Toll-Like Receptor-4 Signaling and Expression on Macrophages Depending on Previous Bacillus Calmette-Guerin Vaccination

    PubMed Central

    Polycarpou, Anastasia; Holland, Martin J.; Karageorgiou, Ioannis; Eddaoudi, Ayad; Walker, Stephen L.; Willcocks, Sam; Lockwood, Diana N. J.

    2016-01-01

    Toll-like receptor (TLR)-1 and TLR2 have been shown to be receptors for Mycobacterium leprae (M. leprae), yet it is unclear whether M. leprae can signal through alternative TLRs. Other mycobacterial species possess ligands for TLR4 and genetic association studies in human populations suggest that people with TLR4 polymorphisms may be protected against leprosy. Using human embryonic kidney (HEK)-293 cells co-transfected with TLR4, we demonstrate that M. leprae activates TLR4. We used human macrophages to show that M. leprae stimulation of cytokine production is diminished if pre-treated with TLR4 neutralizing antibody. TLR4 protein expression was up-regulated on macrophages derived from non-bacillus Calmette-Guerin (BCG) vaccinated healthy volunteers after incubation with M. leprae, whereas it was down-regulated in macrophages derived from BCG-vaccinated donors. Finally, pre-treatment of macrophages derived from BCG-naive donors with BCG reversed the effect of M. leprae on TLR4 expression. This may be a newly described phenomenon by which BCG vaccination stimulates “non-specific” protection to the human immune system. PMID:27458573

  5. Mycobacterium leprae Activates Toll-Like Receptor-4 Signaling and Expression on Macrophages Depending on Previous Bacillus Calmette-Guerin Vaccination.

    PubMed

    Polycarpou, Anastasia; Holland, Martin J; Karageorgiou, Ioannis; Eddaoudi, Ayad; Walker, Stephen L; Willcocks, Sam; Lockwood, Diana N J

    2016-01-01

    Toll-like receptor (TLR)-1 and TLR2 have been shown to be receptors for Mycobacterium leprae (M. leprae), yet it is unclear whether M. leprae can signal through alternative TLRs. Other mycobacterial species possess ligands for TLR4 and genetic association studies in human populations suggest that people with TLR4 polymorphisms may be protected against leprosy. Using human embryonic kidney (HEK)-293 cells co-transfected with TLR4, we demonstrate that M. leprae activates TLR4. We used human macrophages to show that M. leprae stimulation of cytokine production is diminished if pre-treated with TLR4 neutralizing antibody. TLR4 protein expression was up-regulated on macrophages derived from non-bacillus Calmette-Guerin (BCG) vaccinated healthy volunteers after incubation with M. leprae, whereas it was down-regulated in macrophages derived from BCG-vaccinated donors. Finally, pre-treatment of macrophages derived from BCG-naive donors with BCG reversed the effect of M. leprae on TLR4 expression. This may be a newly described phenomenon by which BCG vaccination stimulates "non-specific" protection to the human immune system.

  6. Intervention on toll-like receptors in pancreatic cancer.

    PubMed

    Vaz, Juan; Andersson, Roland

    2014-05-21

    Pancreatic ductal adenocarcinoma (PDA) is a devastating disease with pronounced morbidity and a high mortality rate. Currently available treatments lack convincing cost-efficiency determinations and are in most cases not associated with relevant success rate. Experimental stimulation of the immune system in murine PDA models has revealed some promising results. Toll-like receptors (TLRs) are pillars of the immune system that have been linked to several forms of malignancy, including lung, breast and colon cancer. In humans, TLRs are expressed in the pancreatic cancer tissue and in several cancer cell lines, whereas they are not expressed in the normal pancreas. In the present review, we explore the current knowledge concerning the role of different TLRs associated to PDA. Even if almost all known TLRs are expressed in the pancreatic cancer microenvironment, there are only five TLRs suggested as possible therapeutic targets. Most data points at TLR2 and TLR9 as effective tumor markers and agonists could potentially be used as e.g. future adjuvant therapies. The elucidation of the role of TLR3 in PDA is only in its initial phase. The inhibition/blockage of TLR4-related pathways has shown some promising effects, but there are still many steps left before TLR4 inhibitors can be considered as possible therapeutic agents. Finally, TLR7 antagonists seem to be potential candidates for therapy. Independent of their potential in immunotherapies, all existing data indicate that TLRs are strongly involved in the pathophysiology and development of PDA.

  7. Discovery and Structure-Activity Relationships of the Neoseptins: A New Class of Toll-like Receptor-4 (TLR4) Agonists.

    PubMed

    Morin, Matthew D; Wang, Ying; Jones, Brian T; Su, Lijing; Surakattula, Murali M R P; Berger, Michael; Huang, Hua; Beutler, Elliot K; Zhang, Hong; Beutler, Bruce; Boger, Dale L

    2016-05-26

    Herein, we report studies leading to the discovery of the neoseptins and a comprehensive examination of the structure-activity relationships (SARs) of this new class of small-molecule mouse Toll-like receptor 4 (mTLR4) agonists. The compounds in this class, which emerged from screening an α-helix mimetic library, stimulate the immune response, act by a well-defined mechanism (mouse TLR4 agonist), are easy to produce and structurally manipulate, exhibit exquisite SARs, are nontoxic, and elicit improved and qualitatively different responses compared to lipopolysaccharide, even though they share the same receptor.

  8. A novel toll-like receptor from Mytilus coruscus is induced in response to stress.

    PubMed

    Xu, Mengshan; Wu, Jiong; Ge, Delong; Wu, Changwen; Changfeng Chi; Lv, Zhenming; Liao, Zhi; Liu, Huihui

    2018-07-01

    Toll-like receptor (TLR) is considered to be an evolutionarily conserved transmembrane protein which promotes the Toll signal pathway to active the expression of transcription factors in the innate immunity of the organism. In this study, a full length of TLR homologue of 2525bp in Mytilus coruscus (named as McTLR-a, GenBank accession no: KY940571) was characterized. Its ORF was 1815 bp with a 5'untranslated region (UTR) of 128 bp and a 3'UTR of 582 bp, encoding 602 amino acid residues with a calculated molecular weight of 70.870 kDa (pI = 6.10). BLASTn analysis and phylogenetic relationship strongly suggested that this cDNA sequence was a member of TLR family. Quantitative real time RT-PCR showed that constitutive expression of McTLR-a was occurred, with increasing order in hemocyte, gonad, mantle, adducter, gill and hepatopancreas. Bacterial infection and heavy metals stimulation up-regulated the expression of McTLR-a mRNA in hepatopancreas with time-dependent manners. The maximum expression appeared at 12 h after pathogenic bacteria injection, with approximately 22-fold in Aeromonas hydrophila and 17-fold in Vibrio parahemolyticus higher than that of the blank group. In heavy metals stress group, they all reached peaks at 3d, while the diverse concentration caused the maximum expression were different. The highest expression reached approximately 7-fold higher than the blank in low concentration of Pb 2+ exposure. In Cu 2+ treated group, it reached the peak (approximately 12-fold higher than the blank)in middle concentration. These results indicated that McTLR-a might be involved in the defense response and had a significant role in mediating the environmental stress. Copyright © 2018 Elsevier Ltd. All rights reserved.

  9. Absence of Toll-like receptor 4 signaling results in delayed Yersinia enterocolitica YopP-induced cell death of dendritic cells.

    PubMed

    Gröbner, Sabine; Schulz, Sebastian; Soldanova, Irena; Gunst, Dani S J; Waibel, Michaela; Wesselborg, Sebastian; Borgmann, Stefan; Autenrieth, Ingo B

    2007-01-01

    In an initial period (< or =4 h) Toll-like receptor 4 (TLR4) signaling is required for Yersinia enterocolitica YopP-induced dendritic cell (DC) death. Later (>4 h), DC die independent of TLR4 signaling. In TLR4-deficient DC caspase 8 cleavage is delayed, indicating that TLR4 signaling accelerates caspase 8 activation, leading to DC death.

  10. Starring role of toll-like receptor-4 activation in the gut-liver axis

    PubMed Central

    Carotti, Simone; Guarino, Michele Pier Luca; Vespasiani-Gentilucci, Umberto; Morini, Sergio

    2015-01-01

    Since the introduction of the term “gut-liver axis”, many studies have focused on the functional links of intestinal microbiota, barrier function and immune responses to liver physiology. Intestinal and extra-intestinal diseases alter microbiota composition and lead to dysbiosis, which aggravates impaired intestinal barrier function via increased lipopolysaccharide translocation. The subsequent increased passage of gut-derived product from the intestinal lumen to the organ wall and bloodstream affects gut motility and liver biology. The activation of the toll-like receptor 4 (TLR-4) likely plays a key role in both cases. This review analyzed the most recent literature on the gut-liver axis, with a particular focus on the role of TLR-4 activation. Findings that linked liver disease with dysbiosis are evaluated, and links between dysbiosis and alterations of intestinal permeability and motility are discussed. We also examine the mechanisms of translocated gut bacteria and/or the bacterial product activation of liver inflammation and fibrogenesis via activity on different hepatic cell types. PMID:26600967

  11. DAT isn’t all that: cocaine reward and reinforcement requires Toll Like Receptor 4 signaling

    PubMed Central

    Northcutt, A.L.; Hutchinson, M.R.; Wang, X.; Baratta, M.V.; Hiranita, T.; Cochran, T.A.; Pomrenze, M.B.; Galer, E.L.; Kopajtic, T.A.; Li, C.M.; Amat, J.; Larson, G.; Cooper, D.C.; Huang, Y.; O’Neill, C.E.; Yin, H.; Zahniser, N.R.; Katz, J.L.; Rice, K.C.; Maier, S.F.; Bachtell, R.K.; Watkins, L.R.

    2014-01-01

    The initial reinforcing properties of drugs of abuse, such as cocaine, are largely attributed to their ability to activate the mesolimbic dopamine system. Resulting increases in extracellular dopamine in the nucleus accumbens (NAc) are traditionally thought to result from cocaine’s ability to block dopamine transporters (DATs). Here we demonstrate that cocaine also interacts with the immunosurveillance receptor complex, Toll-Like Receptor 4 (TLR4), on microglial cells to initiate central innate immune signaling. Disruption of cocaine signaling at TLR4 suppresses cocaine-induced extracellular dopamine in the NAc, as well as cocaine conditioned place preference and cocaine self-administration. These results provide a novel understanding of the neurobiological mechanisms underlying cocaine reward/reinforcement that includes a critical role for central immune signaling, and offer a new target for medication development for cocaine abuse treatment. PMID:25644383

  12. RasGRP3 limits Toll-like receptor-triggered inflammatory response in macrophages by activating Rap1 small GTPase.

    PubMed

    Tang, Songqing; Chen, Taoyong; Yu, Zhou; Zhu, Xuhui; Yang, Mingjin; Xie, Bin; Li, Nan; Cao, Xuetao; Wang, Jianli

    2014-08-14

    Host immune cells can detect and destruct invading pathogens via pattern-recognition receptors. Small Rap GTPases act as conserved molecular switches coupling extracellular signals to various cellular responses, but their roles as regulators in Toll-like receptor (TLR) signalling have not been fully elucidated. Here we report that Ras guanine nucleotide-releasing protein 3 (RasGRP3), a guanine nucleotide-exchange factor activating Ras and Rap1, limits production of proinflammatory cytokines (especially IL-6) in macrophages by activating Rap1 on activation by low levels of TLR agonists. We demonstrate that RasGRP3, a dominant member of RasGRPs in macrophages, impairs TLR3/4/9-induced IL-6 production and relieves dextrane sulphate sodium-induced colitis and collagen-induced arthritis. In RasGRP3-deficient RAW264.7 cells obtained by CRISPR-Cas9 genome editing, TLR3/4/9-induced activation of Rap1 was inhibited while ERK1/2 activation was enhanced. Our study suggests that RasGRP3 limits inflammatory response by activating Rap1 on low-intensity pathogen infection, setting a threshold for preventing excessive inflammatory response.

  13. High-Mobility Group Box 1 Inhibits Gastric Ulcer Healing through Toll-Like Receptor 4 and Receptor for Advanced Glycation End Products

    PubMed Central

    Nadatani, Yuji; Watanabe, Toshio; Tanigawa, Tetsuya; Ohkawa, Fumikazu; Takeda, Shogo; Higashimori, Akira; Sogawa, Mitsue; Yamagami, Hirokazu; Shiba, Masatsugu; Watanabe, Kenji; Tominaga, Kazunari; Fujiwara, Yasuhiro; Takeuchi, Koji; Arakawa, Tetsuo

    2013-01-01

    High-mobility group box 1 (HMGB1) was initially discovered as a nuclear protein that interacts with DNA as a chromatin-associated non-histone protein to stabilize nucleosomes and to regulate the transcription of many genes in the nucleus. Once leaked or actively secreted into the extracellular environment, HMGB1 activates inflammatory pathways by stimulating multiple receptors, including Toll-like receptor (TLR) 2, TLR4, and receptor for advanced glycation end products (RAGE), leading to tissue injury. Although HMGB1’s ability to induce inflammation has been well documented, no studies have examined the role of HMGB1 in wound healing in the gastrointestinal field. The aim of this study was to evaluate the role of HMGB1 and its receptors in the healing of gastric ulcers. We also investigated which receptor among TLR2, TLR4, or RAGE mediates HMGB1’s effects on ulcer healing. Gastric ulcers were induced by serosal application of acetic acid in mice, and gastric tissues were processed for further evaluation. The induction of ulcer increased the immunohistochemical staining of cytoplasmic HMGB1 and elevated serum HMGB1 levels. Ulcer size, myeloperoxidase (MPO) activity, and the expression of tumor necrosis factor α (TNFα) mRNA peaked on day 4. Intraperitoneal administration of HMGB1 delayed ulcer healing and elevated MPO activity and TNFα expression. In contrast, administration of anti-HMGB1 antibody promoted ulcer healing and reduced MPO activity and TNFα expression. TLR4 and RAGE deficiency enhanced ulcer healing and reduced the level of TNFα, whereas ulcer healing in TLR2 knockout (KO) mice was similar to that in wild-type mice. In TLR4 KO and RAGE KO mice, exogenous HMGB1 did not affect ulcer healing and TNFα expression. Thus, we showed that HMGB1 is a complicating factor in the gastric ulcer healing process, which acts through TLR4 and RAGE to induce excessive inflammatory responses. PMID:24244627

  14. High-mobility group box 1 inhibits gastric ulcer healing through Toll-like receptor 4 and receptor for advanced glycation end products.

    PubMed

    Nadatani, Yuji; Watanabe, Toshio; Tanigawa, Tetsuya; Ohkawa, Fumikazu; Takeda, Shogo; Higashimori, Akira; Sogawa, Mitsue; Yamagami, Hirokazu; Shiba, Masatsugu; Watanabe, Kenji; Tominaga, Kazunari; Fujiwara, Yasuhiro; Takeuchi, Koji; Arakawa, Tetsuo

    2013-01-01

    High-mobility group box 1 (HMGB1) was initially discovered as a nuclear protein that interacts with DNA as a chromatin-associated non-histone protein to stabilize nucleosomes and to regulate the transcription of many genes in the nucleus. Once leaked or actively secreted into the extracellular environment, HMGB1 activates inflammatory pathways by stimulating multiple receptors, including Toll-like receptor (TLR) 2, TLR4, and receptor for advanced glycation end products (RAGE), leading to tissue injury. Although HMGB1's ability to induce inflammation has been well documented, no studies have examined the role of HMGB1 in wound healing in the gastrointestinal field. The aim of this study was to evaluate the role of HMGB1 and its receptors in the healing of gastric ulcers. We also investigated which receptor among TLR2, TLR4, or RAGE mediates HMGB1's effects on ulcer healing. Gastric ulcers were induced by serosal application of acetic acid in mice, and gastric tissues were processed for further evaluation. The induction of ulcer increased the immunohistochemical staining of cytoplasmic HMGB1 and elevated serum HMGB1 levels. Ulcer size, myeloperoxidase (MPO) activity, and the expression of tumor necrosis factor α (TNFα) mRNA peaked on day 4. Intraperitoneal administration of HMGB1 delayed ulcer healing and elevated MPO activity and TNFα expression. In contrast, administration of anti-HMGB1 antibody promoted ulcer healing and reduced MPO activity and TNFα expression. TLR4 and RAGE deficiency enhanced ulcer healing and reduced the level of TNFα, whereas ulcer healing in TLR2 knockout (KO) mice was similar to that in wild-type mice. In TLR4 KO and RAGE KO mice, exogenous HMGB1 did not affect ulcer healing and TNFα expression. Thus, we showed that HMGB1 is a complicating factor in the gastric ulcer healing process, which acts through TLR4 and RAGE to induce excessive inflammatory responses.

  15. Decreased IL-10 production mediated by Toll-like receptor 9 in B cells in multiple sclerosis.

    PubMed

    Hirotani, Makoto; Niino, Masaaki; Fukazawa, Toshiyuki; Kikuchi, Seiji; Yabe, Ichiro; Hamada, Shinsuke; Tajima, Yasutaka; Sasaki, Hidenao

    2010-04-15

    The complexity of the roles of Toll-like receptors (TLRs) is attributable to their ability to promote or suppress autoimmune diseases. Recent studies have demonstrated that B cells regulate autoimmune diseases, including multiple sclerosis (MS), by producing interleukin (IL)-10. By using CpG DNA as a TLR9 agonist, we investigated the immunoregulatory functions of B cell via TLR9 in MS. Our results indicate that TLR9-mediated IL-10 production by B cells was significantly decreased in MS, and this decrease is likely due to decreased TLR9 expression in memory B cells, suggesting a role of TLR9 in immunoregulation in MS. Copyright 2010 Elsevier B.V. All rights reserved.

  16. Toll-like receptor 7 stimulation by imiquimod induces macrophage autophagy and inflammation in atherosclerotic plaques.

    PubMed

    De Meyer, Inge; Martinet, Wim; Schrijvers, Dorien M; Timmermans, Jean-Pierre; Bult, Hidde; De Meyer, Guido R Y

    2012-05-01

    Atherosclerotic plaques tend to rupture as a consequence of a weakened fibrous cap, particularly in the shoulder regions where most macrophages reside. Macrophages express Toll-like receptors to recognize pathogens and eliminate intracellular pathogens by inducing autophagy. Because Toll-like receptor 7 (TLR7) is thought to be expressed in macrophages but not in smooth muscle cells (SMCs), we investigated whether induction of macrophage autophagic death by TLR7 ligand imiquimod can affect the composition of atherosclerotic plaques in favor of their stability. Immunohistochemical staining of human carotid plaques as well as Western blotting of cultured macrophages and SMCs confirmed that TLR7 was expressed in macrophages, but not in SMCs. In vitro experiments showed that only TLR7 expressing cells underwent imiquimod-induced cell death, which was characterized by autophagosome formation. Imiquimod-treated macrophages activated nuclear factor-κB (NF-κB) and released pro-inflammatory cytokines and chemokines. This effect was inhibited by the glucocorticoid dexamethasone. Imiquimod-induced cytokine release was significantly decreased in autophagy-deficient macrophages because these cells died by necrosis at an accelerated pace. Local in vivo administration of imiquimod to established atherosclerotic lesions in rabbit carotid arteries induced macrophage autophagy without induction of cell death, and triggered cytokine production, upregulation of vascular adhesion molecule-1, infiltration of T-lymphocytes, accumulation of macrophages and enlargement of plaque area. Treatment with dexamethasone suppressed these pro-inflammatory effects in vivo. SMCs and endothelial cells in imiquimod-treated plaques were not affected. In conclusion, imiquimod induces macrophage autophagy in atherosclerotic plaques, but stimulates plaque progression through cytokine release and enhanced infiltration of inflammatory cells.

  17. Toll-like Receptors and B-cell Receptors Synergize to Induce Immunoglobulin Class Switch DNA Recombination: Relevance to Microbial Antibody Responses

    PubMed Central

    Pone, Egest J.; Zan, Hong; Zhang, Jinsong; Al-Qahtani, Ahmed; Xu, Zhenming; Casali, Paolo

    2011-01-01

    Differentiation of naïve B cells, including immunoglobulin (Ig) class switch DNA recombination (CSR), is critical for the immune response and depends on the extensive integration of signals from the B cell receptor (BCR), tumor necrosis factor (TNF) receptor family members, Toll-like receptors (TLRs) and cytokine receptors. TLRs and BCR synergize to induce CSR in T cell-dependent and T cell-independent antibody responses to microbial pathogens. BCR triggering together with simultaneous endosomal TLR engagement leads to enhanced B cell differentiation and antibody responses. The requirement of both BCR and TLR engagement would ensure appropriate antigen-specific activation in an infection. Co-stimulation of TLRs and BCR likely plays a significant role in anti-microbial antibody responses to contain pathogen loads until the T cell-dependent antibody responses peak. Furthermore, the temporal sequence of different signals is also critical for optimal B cell responses, as exemplified by the activation of B cells by initial TLR engagement, leading to the upregulation of co-stimulatory CD80 and MHC-II receptors, which, in turn, result in more efficient interactions with T cells, thereby enhancing the germinal center (GC) reaction and antibody affinity maturation. Overall, BCR and TLR stimulation and the integration with signals from the pathogen or immune cells and their products, determine the ensuing B cell antibody response. PMID:20370617

  18. Nrf2-mediated induction of p62 controls Toll-like receptor-4–driven aggresome-like induced structure formation and autophagic degradation

    PubMed Central

    Fujita, Ken-ichi; Maeda, Daisuke; Xiao, Qi; Srinivasula, Srinivasa M.

    2011-01-01

    Toll-like receptors (TLRs) play a crucial role in several innate immune responses by regulating autophagy, but little is known about how TLR signaling controls autophagy. Here we demonstrate that p62/SQSTM1 is required for TLR4-mediated autophagy, which we show as selective autophagy of aggresome-like induced structures (ALIS). Treatment with LPS or Escherichia coli induced LC3+ dot-like structures, and their assembly, but not lysosomal degradation, occurred independently of classic autophagic machinery. Microscopic and ultrastructural analyses showed that p62 is a component of the induced LC3+ dots and these TLR4-induced p62+ structures resemble ALIS. The levels of p62 mRNA and protein were increased in TLR4-activated cells and knockdown of p62 suppressed the ALIS formation and LC3-II conversion. The accumulation of p62 and ALIS required activation of Nrf2 by reactive oxygen species-p38 axis-dependent TLR4/MyD88 signaling, suggesting a link between innate immune and oxidative-stress responses. These findings indicate that TLR4-driven induction of p62 plays an essential role in the formation and the autophagic degradation of ALIS, which might be critical for regulating host defense. PMID:21220332

  19. Glucuronic acid and the ethanol metabolite ethyl-glucuronide cause Toll-like receptor 4 activation and enhanced pain

    PubMed Central

    Lewis, Susannah S.; Hutchinson, Mark R.; Zhang, Yingning; Hund, Dana K.; Maier, Steven F.; Rice, Kenner C.; Watkins, Linda R.

    2013-01-01

    We have previously observed that the non-opioid morphine metabolite, morphine-3-glucuronide, enhances pain via a toll-like receptor 4 (TLR4) dependent mechanism. The present studies were undertaken to determine whether TLR4-dependent pain enhancement generalizes to other classes of glucuronide metabolites. In silico modeling predicted that glucuronic acid alone and ethyl glucuronide, a minor but long-lasting ethanol metabolite, would dock to the same MD-2 portion of the TLR4 receptor complex previously characterized as the docking site for morphine-3-glucuronide. Glucuronic acid, ethyl glucuronide and ethanol all caused an increase in TLR4-dependent reporter protein expression in a cell line transfected with TLR4 and associated co-signaling molecules. Glucuronic acid-, ethyl glucuronide-, and ethanol-induced increases in TLR4 signaling were blocked by the TLR4 antagonists LPS-RS and (+)-naloxone. Glucuronic acid and ethyl glucuronide both caused allodynia following intrathecal injection in rats, which was blocked by intrathecal co-administration of the TLR4 antagonist LPS-RS. The finding that ethyl glucuronide can cause TLR4-dependent pain could have implications for human conditions such as hangover headache and alcohol withdrawal hyperalgesia, as well as suggesting that other classes of glucuronide metabolites could have similar effects. PMID:23348028

  20. Association of Toll-Like Receptor 3 and Toll-Like Receptor 9 Single Nucleotide Polymorphisms with Hepatitis C Virus Infection and Hepatic Fibrosis in Egyptian Patients

    PubMed Central

    Zayed, Rania A.; Omran, Dalia; Mokhtar, Doha A.; Zakaria, Zinab; Ezzat, Sameera; Soliman, Mohamed A.; Mobarak, Lamiaa; El-Sweesy, Hossam; Emam, Ghada

    2017-01-01

    Toll-like receptors (TLRs) are recognized as fundamental contributors to the immune system function against infections. Hepatitis C virus (HCV) infection represents a global health problem especially in Egypt having the highest HCV prevalence worldwide where HCV infection is a continuing epidemic. The aim of the present study was to investigate the possible association between genetic variation in TLR-3 and TLR-9 and HCV infection and hepatic fibrosis in chronic HCV-positive Egyptian patients. The present study included 100 naïve chronic HCV-positive patients and 100 age- and sex-matched healthy controls. Genotyping of TLR-3 (_7 C/A [rs3775296]), TLR-3 (c.1377C/T [rs3775290]) and TLR-9 (1237T/C [rs5743836]) were done by polymerase chain reaction restriction fragment length polymorphism technique. Frequency of polymorphic genotypes in TLR-3 (_7 C/A), TLR-3 (c.1377C/T) and TLR-9 (1237T/C) were not significantly different between studied HCV-positive patients and controls with P values 0.121, 0.112, and 0.683, respectively. TLR-3 c.1377 T-allele was associated with advanced stage of hepatic fibrosis (P = 0.003). PMID:28093541

  1. [TOLL-LIKE RECEPTORS IN COSMONAUT'S PERIPHERAL BLOOD CELLS AFTER LONG-DURATION MISSIONS TO THE INTERNATIONAL SPACE STATION].

    PubMed

    Berendeeva, T A; Ponomarev, S A; Antropova, E N; Rykova, M P

    2015-01-01

    Studies of Toll-like receptors (TLR) in 20 cosmonauts-members of long-duration (124-199-day) missions to the International space station evidenced changes in relative and absolute counts of peripheral blood monocytes with TLR2, TLR4 and TLR6 on the surface, expression of TLR2 and TLR6 genes, and genes of molecules involved in the TLR signaling pathway and TLR-related NF-KB-, JNK/p38- and IRF pathways on the day of return to Earth. The observed changes displayed individual variability.

  2. Opioid activation of Toll-Like receptor 4 contributes to drug reinforcement

    PubMed Central

    Hutchinson, M.R.; Northcutt, A.L.; Hiranita, T.; Wang, X.; Lewis, S.; Thomas, J.; van Steeg, K.; Kopajtic, T.A.; Loram, L.; Sfregola, C.; Galer, E.; Miles, N.E.; Bland, S.T.; Amat, J.; Rozeske, R.R.; Maslanik, T.; Chapman, T.; Strand, K.; Fleshner, M.; Bachtell, R.K.; Somogyi, A.A.; Yin, H.; Katz, J.L.; Rice, K.C.; Maier, S.F.; Watkins, L.R.

    2012-01-01

    Opioid action was thought to exert reinforcing effects solely via the initial agonism of opioid receptors. Here we present evidence for an additional novel contributor to opioid reward: the innate immune pattern-recognition receptor, Toll-like receptor 4 (TLR4), and its MyD88-dependent signaling. Blockade of TLR4/MD2 by administration of the non-opioid, unnatural isomer of naloxone, (+)-naloxone (rats), or two independent genetic knockouts of MyD88-TLR4-dependent signaling (mice), suppressed opioid-induced conditioned place preference. (+)-Naloxone also reduced opioid (remifentanil) self-administration (rats), another commonly used behavioral measure of drug reward. Moreover, pharmacological blockade of morphine-TLR4/MD2 activity potently reduced morphine-induced elevations of extracellular dopamine in rat nucleus accumbens, a region critical for opioid reinforcement. Importantly, opioid-TLR4 actions are not a unidirectional influence on opioid pharmacodynamics, since TLR4 −/− mice had reduced oxycodone-induced p38 and JNK phosphorylation, whilst displaying potentiated analgesia. Similar to our recent reports of morphine-TLR4/MD2 binding, here we provide a combination of in silico and biophysical data to support (+)-naloxone and remifentanil binding to TLR4/MD2. Collectively, these data indicate that the actions of opioids at classical opioid receptors, together with their newly identified TLR4/MD2 actions, affect the mesolimbic dopamine system which amplifies opioid-induced elevations in extracellular dopamine levels and therefore possibly explaining altered opioid reward behaviors. Thus, the discovery of TLR4/MD2 recognition of opioids as foreign xenobiotic substances adds to the existing hypothesized neuronal reinforcement mechanisms, identifies a new drug target in TLR4/MD2 for the treatment of addictions, and provides further evidence supporting a role for central proinflammatory immune signaling in drug reward. PMID:22895704

  3. Neither Lys- and DAP-type peptidoglycans stimulate mouse or human innate immune cells via Toll-like receptor 2

    PubMed Central

    Langer, Marybeth; Girton, Alanson W.; Popescu, Narcis I.; Burgett, Tarea; Metcalf, Jordan P.

    2018-01-01

    Peptidoglycan (PGN), a major component of bacterial cell walls, is a pathogen-associated molecular pattern (PAMP) that causes innate immune cells to produce inflammatory cytokines that escalate the host response during infection. In order to better understand the role of PGN in infection, we wanted to gain insight into the cellular receptor for PGN. Although the receptor was initially identified as Toll-like receptor 2 (TLR2), this receptor has remained controversial and other PGN receptors have been reported. We produced PGN from live cultures of Bacillus anthracis and Staphylococcus aureus and tested samples of PGN isolated during the purification process to determine at what point TLR2 activity was removed, if at all. Our results indicate that although live B. anthracis and S. aureus express abundant TLR2 ligands, highly-purified PGN from either bacterial source is not recognized by TLR2. PMID:29474374

  4. Role of toll-like receptors in cardiovascular diseases.

    PubMed

    Vallejo, Jesus G

    2011-07-01

    The discovery and characterization of the TLR (Toll-like receptor) family has led to a better understanding of the innate immune system. The strategy of innate immune recognition is based on the detection of constitutive and conserved products of micro-organisms. However, host molecules that are released during injury can also activate TLRs. Engagement of TLRs by microbial or host-derived molecules induces the expression of pro-inflammatory cytokines, which may have both beneficial and detrimental effects on the host. In addition to being expressed in immune cells, TLRs are expressed in other tissues such as those of the cardiovascular system. In the present review, the role of TLRs in septic cardiomyopathy, viral myocarditis, atherosclerosis, ischaemia/reperfusion injury and cardiac remodelling after myocardial infarction are outlined, with attention paid to genetically modified murine models. Although much has been learned about stress-induced TLR activation in the tissues of the cardiovascular system, the role of individual TLRs in initiating and integrating homoeostatic responses within the heart remains to be defined. Accumulating evidence indicates that TLRs may play an important role in the pathogenesis of atherosclerosis, viral myocarditis, dilated cardiomyopathy, cardiac allograft rejection and sepsis-induced left ventricular dysfunction. Moreover, heart failure of diverse aetiology is also now recognized to have an important immune component, with TLR signalling influencing the process of cardiac remodelling and prognosis. In the present review, we outline the biology of TLRs as well as the current experimental and clinical evidence for the role of TLRs in cardiovascular diseases.

  5. Systematic Review of the Relation Between Intestinal Microbiota and Toll-Like Receptors in the Metabolic Syndrome: What Do We Know So Far?

    PubMed

    Portela-Cidade, José Pedro; Borges-Canha, Marta; Leite-Moreira, Adelino Ferreira; Pimentel-Nunes, Pedro

    2015-01-01

    Metabolic syndrome is an emerging problem in developed countries and presents itself as a potential threat worldwide. The role of diabetes, dyslipidaemia and hepatic steatosis as pivotal components of the metabolic syndrome is well known. However, their common persistent chronic inflammation and its potential cause still elude. This systematic review aims to present evidence of the mechanisms that link the intestinal microbioma, innate immunity and metabolic syndrome. A comprehensive research was made using PubMed database and 35 articles were selected. We found that metabolic syndrome is associated to increased levels of innate immunity receptors, namely, Toll-like receptors, both in intestine and systemically and its polymorphisms may change the risk of metabolic syndrome development. Microbioma dysbiosis is also present in metabolic syndrome, with lower prevalence of Bacteroidetes and increased prevalence of Firmicutes populations. The data suggest that the link between intestinal microbiota and Toll-like receptors can negatively endanger the metabolic homeostasis. Current evidence suggests that innate immunity and intestinal microbiota may be the hidden link in the metabolic syndrome development mechanisms. In the near future, this can be the key in the development of new prophylactic and therapeutic strategies to treat metabolic syndrome patients.

  6. Therapeutic impact of toll-like receptors on inflammatory bowel diseases: a multiple-edged sword.

    PubMed

    Cario, Elke

    2008-03-01

    Recent studies have begun to define the mechanisms through which Toll-like receptors (TLRs) regulate intestinal homeostasis in health and disease. Current therapies for inflammatory bowel diseases (IBDs) mostly aim at interrupting the inflammatory cascade through agents that regulate TH1 or TH2 cytokine responses. As recognition grows for TLR dysfunction to play a role in IBD pathogenesis, TLRs could provide another valid interventional target for novel therapy development. However, seemingly contradictory results from studying different murine models of colitis have so far confounded whether therapeutically useful modulation of TLRs is best accomplished by activating, inhibiting, or rather a combination of both at different stages of mucosal disease. This review evaluates potential strategies as well as their rationale and future prospects.

  7. Expression of Toll-Like Receptors 2 and 4 and Related Cytokines in Patients with Hepatic Cystic and Alveolar Echinococcosis

    PubMed Central

    Tuxun, Tuerhongjiang; Ma, Hai-Zhang; Apaer, Shadike; Zhang, Heng; Aierken, Amina; Li, Yu-Peng; Lin, Ren-Yong; Zhao, Jin-Ming; Zhang, Jin-Hui; Wen, Hao

    2015-01-01

    Several studies have demonstrated the important role of Toll-like receptors in various parasitic infections. This study aims to explore expression of Toll-like receptors (TLRs) and related cytokines in patients with human cystic echinococcosis (CE) and alveolar echinococcosis (AE). 78 subjects including AE group (N = 28), CE group (N = 22), and healthy controls (HC, N = 28) were enrolled in this study. The mRNA expression levels of TLR2 and TLR4 in blood and hepatic tissue and plasma levels related cytokines were detected by using ELISA. Median levels of TLR2 mRNA in AE and CE groups were significantly elevated as compared with that in healthy control group. Median levels of TLR4 expression were increased in AE and CE. Plasma concentration levels of IL-5, IL-6, and IL-10 were slightly increased in AE and CE groups compared with those in HC group with no statistical differences (p > 0.05). The IL-23 concentration levels were significantly higher in AE and CE groups than that in HC subjects with statistical significance. The increased expression of TLR2 and IL-23 might play a potential role in modulating tissue infiltrative growth of the parasite and its persistence in the human host. PMID:26635448

  8. Toll-like receptor 4 mediates lipopolysaccharide-induced muscle catabolism via coordinate activation of ubiquitin-proteasome and autophagy-lysosome pathways

    PubMed Central

    Doyle, Alexander; Zhang, Guohua; Abdel Fattah, Elmoataz A.; Eissa, N. Tony; Li, Yi-Ping

    2011-01-01

    Cachectic muscle wasting is a frequent complication of many inflammatory conditions, due primarily to excessive muscle catabolism. However, the pathogenesis and intervention strategies against it remain to be established. Here, we tested the hypothesis that Toll-like receptor 4 (TLR4) is a master regulator of inflammatory muscle catabolism. We demonstrate that TLR4 activation by lipopolysaccharide (LPS) induces C2C12 myotube atrophy via up-regulating autophagosome formation and the expression of ubiquitin ligase atrogin-1/MAFbx and MuRF1. TLR4-mediated activation of p38 MAPK is necessary and sufficient for the up-regulation of atrogin1/MAFbx and autophagosomes, resulting in myotube atrophy. Similarly, LPS up-regulates muscle autophagosome formation and ubiquitin ligase expression in mice. Importantly, autophagy inhibitor 3-methyladenine completely abolishes LPS-induced muscle proteolysis, while proteasome inhibitor lactacystin partially blocks it. Furthermore, TLR4 knockout or p38 MAPK inhibition abolishes LPS-induced muscle proteolysis. Thus, TLR4 mediates LPS-induced muscle catabolism via coordinate activation of the ubiquitin-proteasome and the autophagy-lysosomal pathways.—Doyle, A., Zhang, G., Abdel Fattah, E. A., Eissa, N. T., Li, Y.-P. Toll-like receptor 4 mediates lipopolysaccharide-induced muscle catabolism via coordinate activation of ubiquitin-proteasome and autophagy-lysosome pathways. PMID:20826541

  9. Human Milk Components Modulate Toll-Like Receptor–Mediated Inflammation12

    PubMed Central

    He, YingYing; Lawlor, Nathan T

    2016-01-01

    Toll-like receptor (TLR) signaling is central to innate immunity. Aberrant expression of TLRs is found in neonatal inflammatory diseases. Several bioactive components of human milk modulate TLR expression and signaling pathways, including soluble toll-like receptors (sTLRs), soluble cluster of differentiation (sCD) 14, glycoproteins, small peptides, and oligosaccharides. Some milk components, such as sialyl (α2,3) lactose and lacto-N-fucopentaose III, are reported to increase TLR signaling; under some circumstances this might contribute toward immunologic balance. Human milk on the whole is strongly anti-inflammatory, and contains abundant components that depress TLR signaling pathways: sTLR2 and sCD14 inhibit TLR2 signaling; sCD14, lactadherin, lactoferrin, and 2′-fucosyllactose attenuate TLR4 signaling; 3′-galactosyllactose inhibits TLR3 signaling, and β-defensin 2 inhibits TLR7 signaling. Feeding human milk to neonates decreases their risk of sepsis and necrotizing enterocolitis. Thus, the TLR regulatory components found in human milk hold promise as benign oral prophylactic and therapeutic treatments for the many gastrointestinal inflammatory disorders mediated by abnormal TLR signaling. PMID:26773018

  10. Contrasted evolutionary histories of two Toll-like receptors (Tlr4 and Tlr7) in wild rodents (MURINAE)

    PubMed Central

    2013-01-01

    Background In vertebrates, it has been repeatedly demonstrated that genes encoding proteins involved in pathogen-recognition by adaptive immunity (e.g. MHC) are subject to intensive diversifying selection. On the other hand, the role and the type of selection processes shaping the evolution of innate-immunity genes are currently far less clear. In this study we analysed the natural variation and the evolutionary processes acting on two genes involved in the innate-immunity recognition of Microbe-Associated Molecular Patterns (MAMPs). Results We sequenced genes encoding Toll-like receptor 4 (Tlr4) and 7 (Tlr7), two of the key bacterial- and viral-sensing receptors of innate immunity, across 23 species within the subfamily Murinae. Although we have shown that the phylogeny of both Tlr genes is largely congruent with the phylogeny of rodents based on a comparably sized non-immune sequence dataset, we also identified several potentially important discrepancies. The sequence analyses revealed that major parts of both Tlrs are evolving under strong purifying selection, likely due to functional constraints. Yet, also several signatures of positive selection have been found in both genes, with more intense signal in the bacterial-sensing Tlr4 than in the viral-sensing Tlr7. 92% and 100% of sites evolving under positive selection in Tlr4 and Tlr7, respectively, were located in the extracellular domain. Directly in the Ligand-Binding Region (LBR) of TLR4 we identified two rapidly evolving amino acid residues and one site under positive selection, all three likely involved in species-specific recognition of lipopolysaccharide of gram-negative bacteria. In contrast, all putative sites of LBRTLR7 involved in the detection of viral nucleic acids were highly conserved across rodents. Interspecific differences in the predicted 3D-structure of the LBR of both Tlrs were not related to phylogenetic history, while analyses of protein charges clearly discriminated Rattini and Murini

  11. Toll-like receptor 4-positive macrophages protect mice from Pasteurella pneumotropica-induced pneumonia

    NASA Technical Reports Server (NTRS)

    Hart, Marcia L.; Mosier, Derek A.; Chapes, Stephen K.

    2003-01-01

    This study investigates Toll-like receptor 4 (TLR4)-positive macrophages in early recognition and clearance of pulmonary bacteria. TLR4 is a trans-membrane receptor that is the primary recognition molecule for lipopolysaccharide of gram-negative bacteria. The TLR4(Lps-del) mouse strains C57BL10/ScN (B10) and STOCK Abb(tm1) TLR4(Lps-del) Slc11a1(s)(B10 x C2D) are susceptible to pulmonary infections and develop pneumonia when naturally or experimentally infected by the opportunistic bacterium Pasteurella pneumotropica. Since these mice have the TLR4(Lps-del) genotype, we hypothesized that reconstitution of mice with TLR4-positive macrophages would provide resistance to this bacterium. A cultured macrophage cell line (C2D macrophages) and bone marrow cells from C2D mice were adoptively transferred to B10 and B10 x C2D mice by intraperitoneal injection. C2D macrophages increased B10 and B10 x C2D mouse resistance to P. pneumotropica. In C2D-recipient mice there was earlier transcription of tumor necrosis factor alpha and chemokines JE and macrophage inflammatory protein 2 (MIP-2) in the lungs of B10 and B10 x C2D mice, and there was earlier transcription of KC and MIP-1alpha in B10 x C2D mice. In addition, the course of inflammation following experimental Pasteurella challenge was altered in C2D recipients. C2D macrophages also protected B10 x C2D mice, which lack CD4(+) T cells. These data indicate that macrophages are critical for pulmonary immunity and can provide host resistance to P. pneumotropica. This study indicates that TLR4-positive macrophages are important for early recognition and clearance of pulmonary bacterial infections.

  12. Hydrocortisone reduces the beneficial effects of toll-like receptor 2 deficiency on survival in a mouse model of polymicrobial sepsis.

    PubMed

    Bergt, Stefan; Wagner, Nana-Maria; Heidrich, Manja; Butschkau, Antje; Nöldge-Schomburg, Gabriele E F; Vollmar, Brigitte; Roesner, Jan P

    2013-11-01

    Toll-like receptors (TLRs) play a crucial role in early host defense against microorganisms. Toll-like receptor 2 (TLR2) polymorphisms have a prevalence of 10%; functional defects of TLR2 are associated with higher susceptibility toward gram-positive bacteria, and TLR2 deficiency has been associated with an impaired adrenal stress response. In the present study, we compared endogenous corticosterone production of wild-type (WT) and TLR2-deficient (TLR2) mice and analyzed survival after hydrocortisone therapy during sepsis induced by cecal ligation and puncture (CLP). Male C57BL/6J (WT); and B6.129-Tlr2tm1Kir/J (TLR2) mice were subjected to CLP or sham operation and randomly assigned to postoperative treatment with either hydrocortisone (5 mg/kg) or vehicle (n = 10 mice/group). Survival was documented for an observation period of 48 h. Endogenous corticosterone production following hydrocortisone treatment and lipoteichoic acid (LTA) exposure, interleukin 6 (IL-6) and IL-1β plasma levels, and blood counts were determined following sham operation or CLP using another n = 5 mice/group. Statistical analysis was performed using analysis of variance/Bonferroni. TLR2 mice exhibited a lack of suppression and an attenuated increase in endogenous corticosterone production following hydrocortisone or LTA treatment, respectively. After CLP, TLR2 mice exhibited an uncompromised adrenal stress response, higher IL-6 levels, and increased survival compared with WT controls (75 vs. 35%; P < 0.05). Hydrocortisone therapy of TLR2 mice completely abolished this advantage (decrease in survival to 45%, P < 0.05 vs. vehicle-treated TLR2 mice) and was associated with decreased IL-1β plasma concentrations. Toll-like receptor 2 deficiency is associated with an uncompromised adrenal stress response and increased survival rates during polymicrobial sepsis. Hydrocortisone treatment increases mortality of septic TLR2 mice, suggesting that hydrocortisone therapy might be harmful for

  13. "Host tissue damage" signal ATP promotes non-directional migration and negatively regulates toll-like receptor signaling in human monocytes.

    PubMed

    Kaufmann, Andreas; Musset, Boris; Limberg, Sven H; Renigunta, Vijay; Sus, Rainer; Dalpke, Alexander H; Heeg, Klaus M; Robaye, Bernard; Hanley, Peter J

    2005-09-16

    The activation of Toll-like receptors (TLRs) by lipopolysaccharide or other ligands evokes a proinflammatory immune response, which is not only capable of clearing invading pathogens but can also inflict damage to host tissues. It is therefore important to prevent an overshoot of the TLR-induced response where necessary, and here we show that extracellular ATP is capable of doing this in human monocytes. Using reverse transcription-PCR, we showed that monocytes express P2Y(1), P2Y(2), P2Y(4), P2Y(11), and P2Y(13) receptors, as well as several P2X receptors. To elucidate the function of these receptors, we first studied Ca(2+) signaling in single cells. ATP or UTP induced a biphasic increase in cytosolic Ca(2+), which corresponded to internal Ca(2+) release followed by activation of store-operated Ca(2+) entry. The evoked Ca(2+) signals stimulated Ca(2+)-activated K(+) channels, producing transient membrane hyperpolarization. In addition, ATP promoted cytoskeleton reorganization and cell migration; however, unlike chemoattractants, the migration was non-directional and further analysis showed that ATP did not activate Akt, essential for sensing gradients. When TLR2, TLR4, or TLR2/6 were stimulated with their respective ligands, ATPgammaS profoundly inhibited secretion of proinflammatory cytokines (tumor necrosis factor-alpha and monocyte chemoattractant protein-1) but increased the production of interleukin-10, an anti-inflammatory cytokine. In radioimmune assays, we found that ATP (or ATPgammaS) strongly increased cAMP levels, and, moreover, the TLR-response was inhibited by forskolin, whereas UTP neither increased cAMP nor inhibited the TLR-response. Thus, our data suggest that ATP promotes non-directional migration and, importantly, acts as a "host tissue damage" signal via the G(s) protein-coupled P2Y(11) receptor and increased cAMP to negatively regulate TLR signaling.

  14. Cot/tpl2-MKK1/2-Erk1/2 controls mTORC1-mediated mRNA translation in Toll-like receptor-activated macrophages.

    PubMed

    López-Pelaéz, Marta; Fumagalli, Stefano; Sanz, Carlos; Herrero, Clara; Guerra, Susana; Fernandez, Margarita; Alemany, Susana

    2012-08-01

    Cot/tpl2 is the only MAP3K that activates MKK1/2-Erk1/2 in Toll-like receptor-activated macrophages. Here we show that Cot/tpl2 regulates RSK, S6 ribosomal protein, and 4E-BP phosphorylation after stimulation of bone marrow-derived macrophages with lipopolysaccharide (LPS), poly I:C, or zymosan. The dissociation of the 4E-BP-eIF4E complex, a key event in the cap-dependent mRNA translation initiation, is dramatically reduced in LPS-stimulated Cot/tpl2-knockout (KO) macrophages versus LPS-stimulated wild-type (Wt) macrophages. Accordingly, after LPS activation, increased cap-dependent translation is observed in Wt macrophages but not in Cot/tpl2 KO macrophages. In agreement with these data, Cot/tpl2 increases the polysomal recruitment of the 5´ TOP eEF1α and eEF2 mRNAs, as well as of inflammatory mediator gene-encoding mRNAs, such as tumor necrosis factor α (TNFα), interleukin-6 (IL-6), and KC in LPS-stimulated macrophages. In addition, Cot/tpl2 deficiency also reduces total TNFα, IL-6, and KC mRNA expression in LPS-stimulated macrophages, which is concomitant with a decrease in their mRNA half-lives. Macrophages require rapid fine control of translation to provide an accurate and not self-damaging response to host infection, and our data show that Cot/tpl2 controls inflammatory mediator gene-encoding mRNA translation in Toll-like receptor-activated macrophages.

  15. Chronic exposure to indoxacarb and pulmonary expression of toll-like receptor-9 in mice.

    PubMed

    Kaur, Sandeep; Mukhopadhyay, C S; Sethi, R S

    2016-11-01

    Chronic exposure to indoxacarb and pulmonary expression of toll-like receptor 9 (TLR-9) in mice. In this study, healthy male Swiss albino mice (n=30) aging 8-10 weeks were used to evaluate TLR-9 expression in lungs of mice following indoxacarb exposure with and without lipopolysaccharide (LPS). Indoxacarb was administered orally dissolved in groundnut oil at 4 and 2 mg/kg/day for 90 days. On day 91, five animals from each group were challenged with LPS/normal saline solution at 80 µg/animal. The lung tissues were processed for real time and immunohistochemical studies. LPS resulted increase in fold change m-RNA expression level of TLR-9 as compare to control, while indoxacarb (4 mg/kg) alone and in combination with LPS resulted 16.21-fold change and 29.4-fold change increase in expression of TLR-9 m-RNA, respectively, as compared to control. Similarly, indoxacarb (2 mg/kg) alone or in combination with LPS also altered TLR-9 expression. Further at protein level control group showed minimal expression of TLR-9 in lungs as compare to other groups, however, LPS group showed intense positive staining in bronchial epithelium as well as in alveolar septal cells. Indoxacarb at both doses individually showed strong immuno-positive reaction as compare to control, however when combined with LPS resulted intense staining in airway epithelium as compare to control. Chronic oral administration of indoxacarb for 90 days (4 and 2 mg/kg) alters expression of TLR-9 at m-RNA and protein level and co-exposure with LPS exhibited synergistic effect.

  16. Bacterial lysates improve the protective antibody response against respiratory viruses through Toll-like receptor 4

    PubMed Central

    Coviello, Silvina; Wimmenauer, Vera; Polack, Fernando P; Irusta, Pablo M

    2014-01-01

    Respiratory viruses cause significant morbidity and mortality in infants and young children worldwide. Current strategies to modulate the immune system and prevent or treat respiratory viral infections in this age group have shown limited success. Here, we demonstrate that a lysate derived from Gram-positive and Gram-negative organisms positively modulates protective antibody responses against both respiratory syncytial virus (RSV) and influenza virus in murine models of infection. Interestingly, despite the complex mixture of Toll-like receptor (TLR) agonists present in the bacterial lysate, the modulatory effects were mostly dependent on TLR4 signaling. Our results indicate that the use of simple formulations of TLR-agonists can significantly improve the immune response against critical pediatric respiratory pathogens. PMID:25483455

  17. Microglial cells and peritoneal macrophages release activin A upon stimulation with Toll-like receptor agonists.

    PubMed

    Ebert, Sandra; Zeretzke, Moritz; Nau, Roland; Michel, Uwe

    2007-02-21

    Activin A levels are elevated in the cerebrospinal fluid (CSF) of patients with meningitis and in the sera of patients with sepsis. The source(s) of the elevated concentrations of activin A in CSF and serum have not yet been discovered. Here we demonstrate that primary mouse microglial cells and peritoneal macrophages release activin A after treatment with agonists of Toll-like receptor (TLR) 2, 4, and 9. These findings provide further evidence for a role of activin in the innate immune response and suggest that microglial cells and macrophages are a source of elevated activin A concentrations observed in the CSF during bacterial meningitis and in the systemic circulation during sepsis.

  18. Association between toll-like receptors expression and major depressive disorder.

    PubMed

    Hung, Yi-Yung; Kang, Hong-Yo; Huang, Kai-Wei; Huang, Tiao-Lai

    2014-12-15

    Accumulating evidences suggest that Toll-like receptors (TLRs) were involved in the pathophysiology of major depressive disorder. TLR4 was thought to be associated with major depressive disorder in animal model, but the others were still unknown. In order to examine TLR1-9 mRNA expression levels in peripheral blood and their relationships with the psychopathology of major depressive disorder, 30 patients with major depressive disorder were compared with 29 healthy controls. The 17-item Hamilton Depression Rating Scale (HAMD-17) was used to assess the severity of major depression. The mRNA expression levels of TLRs were examined in parallel with a housekeeping gene using real-time polymerase chain reaction (RT-PCR). Analysis of covariance with age and body mass index adjustment revealed a significantly higher expression of TLR3, 4, 5 and 7 mRNA but lower expression of TLR1 and 6 in patients with major depressive disorder as compared with healthy controls. Multiple linear regression analysis revealed that TLR4 was an independent risk factor relating to severity of major depression. These findings suggest that TLRs, especially TLR4, may be involved in the psychopathology of major depression. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  19. Apoptosis, Toll-like, RIG-I-like and NOD-like Receptors Are Pathways Jointly Induced by Diverse Respiratory Bacterial and Viral Pathogens

    PubMed Central

    Martínez, Isidoro; Oliveros, Juan C.; Cuesta, Isabel; de la Barrera, Jorge; Ausina, Vicente; Casals, Cristina; de Lorenzo, Alba; García, Ernesto; García-Fojeda, Belén; Garmendia, Junkal; González-Nicolau, Mar; Lacoma, Alicia; Menéndez, Margarita; Moranta, David; Nieto, Amelia; Ortín, Juan; Pérez-González, Alicia; Prat, Cristina; Ramos-Sevillano, Elisa; Regueiro, Verónica; Rodriguez-Frandsen, Ariel; Solís, Dolores; Yuste, José; Bengoechea, José A.; Melero, José A.

    2017-01-01

    Lower respiratory tract infections are among the top five leading causes of human death. Fighting these infections is therefore a world health priority. Searching for induced alterations in host gene expression shared by several relevant respiratory pathogens represents an alternative to identify new targets for wide-range host-oriented therapeutics. With this aim, alveolar macrophages were independently infected with three unrelated bacterial (Streptococcus pneumoniae, Klebsiella pneumoniae, and Staphylococcus aureus) and two dissimilar viral (respiratory syncytial virus and influenza A virus) respiratory pathogens, all of them highly relevant for human health. Cells were also activated with bacterial lipopolysaccharide (LPS) as a prototypical pathogen-associated molecular pattern. Patterns of differentially expressed cellular genes shared by the indicated pathogens were searched by microarray analysis. Most of the commonly up-regulated host genes were related to the innate immune response and/or apoptosis, with Toll-like, RIG-I-like and NOD-like receptors among the top 10 signaling pathways with over-expressed genes. These results identify new potential broad-spectrum targets to fight the important human infections caused by the bacteria and viruses studied here. PMID:28298903

  20. Lipids Derived from Virulent Francisella tularensis Broadly Inhibit Pulmonary Inflammation via Toll-Like Receptor 2 and Peroxisome Proliferator-Activated Receptor α

    PubMed Central

    Crane, Deborah D.; Ireland, Robin; Alinger, Joshua B.; Small, Pamela

    2013-01-01

    Francisella tularensis is a Gram-negative facultative intracellular pathogen that causes an acute lethal respiratory disease in humans. The heightened virulence of the pathogen is linked to its unique ability to inhibit Toll-like receptor (TLR)-mediated inflammatory responses. The bacterial component and mechanism of this inhibition are unknown. Here we show that lipids isolated from virulent but not attenuated strains of F. tularensis are not detected by host cells, inhibit production of proinflammatory cytokines by primary macrophages in response to known TLR ligands, and suppress neutrophil recruitment in vivo. We further show that lipid-mediated inhibition of inflammation is dependent on TLR2, MyD88, and the nuclear hormone and fatty acid receptor peroxisome proliferator-activated receptor α (PPARα). Pathogen lipid-mediated interference with inflammatory responses through the engagement of TLR2 and PPARα represents a novel manipulation of host signaling pathways consistent with the ability of highly virulent F. tularensis to efficiently evade host immune responses. PMID:23925884

  1. Chloroquine and inhibition of Toll-like receptor 9 protect from sepsis-induced acute kidney injury

    PubMed Central

    Yasuda, Hideo; Leelahavanichkul, Asada; Tsunoda, Shinichiro; Dear, James W.; Takahashi, Yoshiyuki; Ito, Shuichi; Hu, Xuzhen; Zhou, Hua; Doi, Kent; Childs, Richard; Klinman, Dennis M.; Yuen, Peter S.T.; Star, Robert A.

    2008-01-01

    Mortality from sepsis has remained high despite recent advances in supportive and targeted therapies. Toll-like receptors (TLRs) sense bacterial products and stimulate pathogenic innate immune responses. Mice deficient in the common adapter protein MyD88, downstream from most TLRs, have reduced mortality and acute kidney injury (AKI) from polymicrobial sepsis. However, the identity of the TLR(s) responsible for the host response to polymicrobial sepsis is unknown. Here, we show that chloroquine, an inhibitor of endocytic TLRs (TLR3, 7, 8, 9), improves sepsis-induced mortality and acute kidney injury in a clinically relevant polymicrobial sepsis mouse model, even when administered 6h after the septic insult. Chloroquine administration attenuated the decline in renal function, splenic apoptosis, serum markers of damage to other organs, and prototypical serum pro- and anti-inflammatory cytokines TNF-alpha and IL-10. An oligodeoxynucleotide inhibitor (H154) of TLR9 and TLR9-deficient mice mirror the actions of chloroquine in all functional parameters that we tested. In addition, chloroquine decreased TLR9 protein abundance in spleen, further suggesting that TLR9 signaling may be a major target for the protective actions of chloroquine. Our findings indicate that chloroquine improves survival by inhibiting multiple pathways leading to polymicrobial sepsis, and that chloroquine and TLR9 inhibitors represent viable broad-spectrum and targeted therapeutic strategies, respectively, that are promising candidates for further clinical development. PMID:18305095

  2. Single-nucleotide polymorphisms in Toll-like receptor (TLR)-2, TLR4 and heat shock protein 70 genes and susceptibility to scrub typhus.

    PubMed

    Janardhanan, Jeshina; Joseph Martin, Sherry; Astrup, Elisabeth; Veeramanikandan, R; Aukrust, Pål; Abraham, Ooriapadickal C; Varghese, George M

    2013-11-01

    Scrub typhus is a highly prevalent bacterial infection in India and South Asia that is caused by Orientia tsutsugamushi. The innate immune response to infections is modulated by Toll-like receptors (TLRs) and heat shock proteins (HSPs). This study was done to assess the prevalence and possible association of TLR and HSP polymorphisms in scrub typhus. TLR4 Asp299Gly, TLR4 Thr399Ile, TLR2 Arg753Gln and HSP70-2 A1267G are single-nucleotide polymorphisms (SNPs) that may modulate their activities, and these SNPs were assessed in 137 scrub typhus patients and 134 controls by PCR restriction fragment length polymorphism. We found that the two TLR4 mutations, TLR4 D299G and TLR4T399I, were present in 19.5% and 22% of the study population, respectively, and was in significant linkage disequilibrium with a D' of 0.8. The TLR2 mutation was found to be rare, whereas the HSP A>G mutation was very common (77.5%). Compared with the controls, the prevalence of heterozygous genotype of the TLR4D299G SNP, but not any of the other SNPs, was significantly higher among scrub typhus patients. Further studies using a larger sample size and more candidate genes may better enable in determining the role of these associations in susceptibility and severity of scrub typhus.

  3. The circadian clock controls toll-like receptor 9-mediated innate and adaptive immunity

    PubMed Central

    Silver, Adam C.; Arjona, Alvaro; Walker, Wendy E.; Fikrig, Erol

    2012-01-01

    Circadian rhythms refer to biologic processes that oscillate with a period of approximately 24 hours. These rhythms are sustained by a molecular clock and provide a temporal matrix that ensures the coordination of homeostatic processes with the periodicity of environmental challenges. We demonstrate the circadian molecular clock controls the expression and function of toll like receptor 9 (TLR9). In a vaccination model using TLR9 ligand as adjuvant, mice immunized at the time of enhanced TLR9 responsiveness presented weeks later with an improved adaptive immune response. In a TLR9-dependent mouse model of sepsis, we found that disease severity was dependent on the timing of sepsis induction, coinciding with the daily changes in TLR9 expression and function. These findings unveil a direct molecular link between the circadian and innate immune systems with important implications for immunoprophylaxis and immunotherapy. PMID:22342842

  4. The Structural Basis for Endotoxin-induced Allosteric Regulation of the Toll-like Receptor 4 (TLR4) Innate Immune Receptor*

    PubMed Central

    Paramo, Teresa; Piggot, Thomas J.; Bryant, Clare E.; Bond, Peter J.

    2013-01-01

    As part of the innate immune system, Toll-like receptor 4 (TLR4) recognizes bacterial cell surface lipopolysaccharide (LPS) by forming a complex with a lipid-binding co-receptor, MD-2. In the presence of agonist, TLR4·MD-2 dimerizes to form an active receptor complex, leading to initiation of intracellular inflammatory signals. TLR4 is of great biomedical interest, but its pharmacological manipulation is complicated because even subtle variations in the structure of LPS can profoundly impact the resultant immunological response. Here, we use atomically detailed molecular simulations to gain insights into the nature of the molecular signaling mechanism. We first demonstrate that MD-2 is extraordinarily flexible. The “clamshell-like” motions of its β-cup fold enable it to sensitively match the volume of its hydrophobic cavity to the size and shape of the bound lipid moiety. We show that MD-2 allosterically transmits this conformational plasticity, in a ligand-dependent manner, to a phenylalanine residue (Phe-126) at the cavity mouth previously implicated in TLR4 activation. Remarkably, within the receptor complex, we observe spontaneous transitions between active and inactive signaling states of Phe-126, and we confirm that Phe-126 is indeed the “molecular switch” in endotoxic signaling. PMID:24178299

  5. Improved Chemotherapeutic Activity by Morus alba Fruits through Immune Response of Toll-Like Receptor 4.

    PubMed

    Chang, Bo Yoon; Kim, Seon Beom; Lee, Mi Kyeong; Park, Hyun; Kim, Sung Yeon

    2015-10-13

    Morus alba L. fruits have long been used in traditional medicine by many cultures. Their medicinal attributes include cardiovascular, hepatoprotective, neuroprotective and immunomodulatory actions. However, their mechanism of macrophage activation and anti-cancer effects remain unclear. The present study investigated the molecular mechanisms of immune stimulation and improved chemotherapeutic effect of M. alba L. fruit extract (MFE). MFE stimulated the production of cytokines, nitric oxide (NO) and tumor necrosis factor-α (TNF-α) and tumoricidal properties of macrophages. MFE activated macrophages through the mitogen-activated protein kinase (MAPKinase) and nuclear factor-κB (NF-κB) signaling pathways downstream from toll-like receptor (TLR) 4. MFE was shown to exhibit cytotoxicity of CT26 cells via the activated macrophages, even though MFE did not directly affect CT26 cells. In a xenograft mouse model, MFE significantly enhanced anti-cancer activity combined with 5-fluorouracil and markedly promoted splenocyte proliferation, natural killer (NK) cell activity, cytotoxic T lymphocyte (CTL) activity and IFN-γ production. Immunoglobulin G (IgG) antibody levels were significantly increased. These results indicate the indirect anti-cancer activity of MFE through improved immune response mediated by TLR4 signaling. M. alba L. fruit extract might be a potential anti-tumor immunomodulatory candidate chemotherapy agent.

  6. Improved Chemotherapeutic Activity by Morus alba Fruits through Immune Response of Toll-Like Receptor 4

    PubMed Central

    Chang, Bo Yoon; Kim, Seon Beom; Lee, Mi Kyeong; Park, Hyun; Kim, Sung Yeon

    2015-01-01

    Morus alba L. fruits have long been used in traditional medicine by many cultures. Their medicinal attributes include cardiovascular, hepatoprotective, neuroprotective and immunomodulatory actions. However, their mechanism of macrophage activation and anti-cancer effects remain unclear. The present study investigated the molecular mechanisms of immune stimulation and improved chemotherapeutic effect of M. alba L. fruit extract (MFE). MFE stimulated the production of cytokines, nitric oxide (NO) and tumor necrosis factor-α (TNF-α) and tumoricidal properties of macrophages. MFE activated macrophages through the mitogen-activated protein kinase (MAPKinase) and nuclear factor-κB (NF-κB) signaling pathways downstream from toll-like receptor (TLR) 4. MFE was shown to exhibit cytotoxicity of CT26 cells via the activated macrophages, even though MFE did not directly affect CT26 cells. In a xenograft mouse model, MFE significantly enhanced anti-cancer activity combined with 5-fluorouracil and markedly promoted splenocyte proliferation, natural killer (NK) cell activity, cytotoxic T lymphocyte (CTL) activity and IFN-γ production. Immunoglobulin G (IgG) antibody levels were significantly increased. These results indicate the indirect anti-cancer activity of MFE through improved immune response mediated by TLR4 signaling. M. alba L. fruit extract might be a potential anti-tumor immunomodulatory candidate chemotherapy agent. PMID:26473845

  7. Toll like receptor 4: A novel signaling pathway during renal fibrogenesis

    PubMed Central

    Campbell, Matthew T.; Hile, Karen L; Zhang, Hongji; Asanuma, Hiroshi; Vanderbrink, Brian A.; Rink, Richard R.; Meldrum, Kirstan K.

    2010-01-01

    Background The toll like receptor (TLR) family serves an important regulatory role in the innate immune system, and recent evidence has implicated TLR signaling in the pro-inflammatory response of a variety of endogenous and exogenous stimuli within the kidney. The role of TLR signaling in fibrotic renal injury; however, remains unknown. Materials and Methods C3H/HeJ TLR4 hyporesponsive mice (TLR4Lps-d) or WT controls (C3H/Heou/J) underwent either sham operation or 1 week of unilateral ureteral obstruction (UUO). The kidneys were harvested and tissues were analyzed for TLR4 expression (Western Blot; RTPCR), E-cadherin and α-SMA expression (Western Blot), fibroblast accumulation (fibroblast specific protein (FSP-1+) staining), renal fibrosis (collagen I RTPCR, total collagen assay, Masson's trichrome staining), cytokine gene expression (tumor necrosis factor-α (TNF-α) and transforming growth factor-beta1 (TGF-β1) RTPCR), and pSMAD2 and integrin α1 expression (Western Blot). Results Mice with intact TLR4 signaling demonstrate a significant increase in TLR4 expression, α-SMA expression, fibroblast accumulation, collagen deposition, and interstitial fibrosis, and a significant decrease in E-cadherin expression in response to UUO. TLR4 deficient mice; however, exhibit a significant reduction in obstruction-induced α-SMA expression, fibroblast accumulation, and renal fibrosis, with preservation of E-cadherin expression. TLR4's influence on fibroblast accumulation and renal fibrosis occurred independent of any alterations in TNF-α,TGF-β1, or pSMAD2 expression, but did involve alterations integrin α1 expression. Conclusion TLR4 appears to be a significant mediator of fibrotic renal injury. While TLR4 signaling is recognized as a critical component of the innate immune response, this is the first study to demonstrate a novel role for TLR4 in renal fibroblast accumulation and tubulointerstitial fibrosis. PMID:20089260

  8. Toll-like Receptor 3 (TLR3) Induces Apoptosis via Death Receptors and Mitochondria by Up-regulating the Transactivating p63 Isoform α (TAP63α)*

    PubMed Central

    Sun, Ruili; Zhang, Yu; Lv, Qingshan; Liu, Bei; Jin, Miao; Zhang, Weijia; He, Qing; Deng, Minjie; Liu, Xueting; Li, Guancheng; Li, Yuehui; Zhou, Guohua; Xie, Pingli; Xie, Xiumei; Hu, Jinyue; Duan, Zhaojun

    2011-01-01

    Toll-like receptor 3 (TLR3), a member of the pathogen recognition receptors, is widely expressed in various cells and has been shown to activate immune signaling pathways by recognizing viral double-stranded RNA. Recently, it was reported that the activation of TLR3 induced apoptosis in some cells, but the detailed molecular mechanism is not fully understood. In this study, we found that in endothelial cells polyinosinic-polycytidylic acid (poly(I-C)) induced dose- and time-dependent cell apoptosis, which was elicited by TLR3 activation, as TLR3 neutralization and down-regulation repressed the apoptosis. Poly(I-C) induced the activation of both caspases 8 and 9, indicating that TLR3 triggered the signaling of both the extrinsic and intrinsic apoptotic pathways. Poly(I-C) up-regulated tumor necrosis factor-related apoptosis-inducing ligand and its receptors, death receptors 4/5, resulting in initiating the extrinsic pathway. Furthermore, poly(I-C) down-regulated anti-apoptotic protein, B cell lymphoma 2 (Bcl-2), and up-regulated Noxa, a key Bcl-2 homology 3-only antagonist of Bcl-2, leading to the priming of the intrinsic pathway. A p53-related protein, the transactivating p63 isoform α (TAp63α), was induced by TLR3 activation and contributed to the activation of both the intrinsic and extrinsic apoptotic pathways. Both the cells deficient in p63 gene expression by RNA interference and cells that overexpressed the N-terminally truncated p63 isoform α (ΔNp63α), a dominant-negative variant of TAp63α, by gene transfection, survived TLR3 activation. Taken together, TAp63α is a crucial regulator downstream of TLR3 to induce cell death via death receptors and mitochondria. PMID:21367858

  9. Alcohol, nutrition and liver cancer: Role of Toll-like receptor signaling

    PubMed Central

    French, Samuel W; Oliva, Joan; French, Barbara A; Li, Jun; Bardag-Gorce, Fawzia

    2010-01-01

    This article reviews the evidence that ties the development of hepatocellular carcinoma (HCC) to the natural immune pro-inflammatory response to chronic liver disease, with a focus on the role of Toll-like receptor (TLR) signaling as the mechanism of liver stem cell/progenitor transformation to HCC. Two exemplary models of this phenomenon are reviewed in detail. One model applies chronic ethanol/lipopolysaccharide feeding to the activated TLR4 signaling pathway. The other applies chronic feeding of a carcinogenic drug, in which TLR2 and 4 signaling pathways are activated. In the drug-induced model, two major methyl donors, S-adenosylmethionine and betaine, prevent the upregulation of the TLR signaling pathways and abrogate the stem cell/progenitor proliferation response when fed with the carcinogenic drug. This observation supports a nutritional approach to liver cancer prevention and treatment. The observation that upregulation of the TLR signaling pathways leads to liver tumor formation gives evidence to the popular concept that the chronic pro-inflammatory response is an important mechanism of liver oncogenesis. It provides a nutritional approach, which could prevent HCC from developing in many chronic liver diseases. PMID:20238401

  10. Targeting the Toll of Drug Abuse: The Translational Potential of Toll-Like Receptor 4

    PubMed Central

    Bachtell, Ryan; Hutchinson, Mark R.; Wang, Xiaohui; Rice, Kenner C.; Maier, Steven F; Watkins, Linda R.

    2017-01-01

    There is growing recognition that glial proinflammatory activation importantly contributes to the rewarding and reinforcing effects of a variety of drugs of abuse, including cocaine, methamphetamine, opioids, and alcohol. It has recently been proposed that glia are recognizing, and becoming activated by, such drugs as a CNS immunological response to these agents being xenobiotics; that is, substances foreign to the brain. Activation of glia, primarily microglia, by various drugs of abuse occurs via toll like receptor 4 (TLR4). The detection of such xenobiotics by TLR4 results in the release of glial neuroexcitatory and neurotoxic substances. These glial products of TLR4 activation enhance neuronal excitability within brain reward circuitry, thereby enhancing their rewarding and reinforcing effects. Indeed, selective pharmacological blockade of TLR4 activation, such as with the non-opioid TLR4 antagonist (+)-naltrexone, suppresses a number of indices of drug reward/reinforcement. These include: conditioned place preference, self-administration, drug-primed reinstatement, incubation of craving, and elevations of nucleus accumbens shell dopamine. Notably, TLR4 blockade fails to alter self-administration of food, indicative of a selective effect on drugs of abuse. Genetic disruption of TLR4 signaling recapitulates the effects of pharmacological TLR4 blockade, providing converging lines of evidence of a central importance of TLR4. Taken together, multiple lines of evidence converge to raise TLR4 as a promising therapeutic target for drug abuse. PMID:26022268

  11. Mannan-Binding Lectin Inhibits Candida albicans-Induced Cellular Responses in PMA-Activated THP-1 Cells through Toll-Like Receptor 2 and Toll-Like Receptor 4

    PubMed Central

    Yang, Jianbin; Zhao, Dongfang; Wang, Hongpo; Shao, Feng; Wang, Wenjun; Sun, Ruili; Ling, Mingzhi; Zhai, Jingjing; Song, Shijun

    2013-01-01

    Background Candida albicans (C. albicans), the most common human fungal pathogen, can cause fatal systemic infections under certain circumstances. Mannan-binding lectin (MBL),a member of the collectin family in the C-type lectin superfamily, is an important serum component associated with innate immunity. Toll-like receptors (TLRs) are expressed extensively, and have been shown to be involved in C. albicans-induced cellular responses. We first examined whether MBL modulated heat-killed (HK) C. albicans-induced cellular responses in phorbol 12-myristate 13-acetate (PMA)-activated human THP-1 macrophages. We then investigated the possible mechanisms of its inhibitory effect. Methodology/Principal Finding Enzyme-linked immunosorbent assay (ELISA) and reverse transcriptasepolymerase chain reaction (RT-PCR) analysis showed that MBL at higher concentrations (10–20 µg/ml) significantly attenuated C. albicans-induced chemokine (e.g., IL-8) and proinflammatory cytokine (e.g., TNF-α) production from PMA-activated THP-1 cells at both protein and mRNA levels. Electrophoretic mobility shift assay (EMSA) and Western blot (WB) analysis showed that MBL could inhibit C. albicans-induced nuclear factor-κB (NF-κB) DNA binding and its translocation in PMA-activated THP-1 cells. MBL could directly bind to PMA-activated THP-1 cells in the presence of Ca2+, and this binding decreased TLR2 and TLR4 expressions in C. albicans-induced THP-1 macrophages. Furthermore, the binding could be partially inhibited by both anti-TLR2 monoclonal antibody (clone TL2.1) and anti-TLR4 monoclonal antibody (clone HTA125). In addition, co-immunoprecipitation experiments and microtiter wells assay showed that MBL could directly bind to the recombinant soluble form of extracellular TLR2 domain (sTLR2) and sTLR4. Conclusions/Significance Our study demonstrates that MBL can affect proinflammatory cytokine and chemokine expressions by modifying C. albicans-/TLR-signaling pathways. This study supports an

  12. Macrophage interleukin-6 and tumour necrosis factor-α are induced by coronavirus fixation to Toll-like receptor 2/heparan sulphate receptors but not carcinoembryonic cell adhesion antigen 1a

    PubMed Central

    Jacques, Alexandre; Bleau, Christian; Turbide, Claire; Beauchemin, Nicole; Lamontagne, Lucie

    2009-01-01

    A rapid antiviral immune response may be related to viral interaction with the host cell leading to activation of macrophages via pattern recognition receptors (PPRs) or specific viral receptors. Carcinoembryonic cell adhesion antigen 1a (CEACAM1a) is the specific receptor for the mouse hepatitis virus (MHV), a coronavirus known to induce acute viral hepatitis in mice. The objective of this study was to understand the mechanisms responsible for the secretion of high-pathogenic MHV3-induced inflammatory cytokines. We report that the induction of the pro-inflammatory cytokines interleukin (IL)-6 and tumour necrosis factor (TNF)-α in peritoneal macrophages does not depend on CEACAM1a, as demonstrated in cells isolated from Ceacam1a−/− mice. The induction of IL-6 and TNF-α production was related rather to the fixation of the spike (S) protein of MHV3 on Toll-like receptor 2 (TLR2) in regions enriched in heparan sulphate and did not rely on viral replication, as demonstrated with denatured S protein and UV-inactivated virus. High levels of IL-6 and TNF-α were produced in livers from infected C57BL/6 mice but not in livers from Tlr2−/− mice. The histopathological observations were correlated with the levels of those inflammatory cytokines. Depending on mouse strain, the viral fixation to heparan sulfate/TLR2 stimulated differently the p38 mitogen-activated protein kinase (MAPK) and nuclear factor (NF)-κB in the induction of IL-6 and TNF-α. These results suggest that TLR2 and heparan sulphate receptors can act as new viral PPRs involved in inflammatory responses. PMID:19740307

  13. Structure of the Toll-Spatzle complex, a molecular hub in Drosophila development and innate immunity.

    PubMed

    Parthier, Christoph; Stelter, Marco; Ursel, Christian; Fandrich, Uwe; Lilie, Hauke; Breithaupt, Constanze; Stubbs, Milton T

    2014-04-29

    Drosophila Toll receptors are involved in embryonic development and the immune response of adult flies. In both processes, the only known Toll receptor ligand is the human nerve growth factor-like cystine knot protein Spätzle. Here we present the crystal structure of a 1:1 (nonsignaling) complex of the full-length Toll receptor ectodomain (ECD) with the Spätzle cystine knot domain dimer. The ECD is divided into two leucine-rich repeat (LRR) domains, each of which is capped by cysteine-rich domains. Spätzle binds to the concave surface of the membrane-distal LRR domain, in contrast to the flanking ligand interactions observed for mammalian Toll-like receptors, with asymmetric contributions from each Spätzle protomer. The structure allows rationalization of existing genetic and biochemical data and provides a framework for targeting the immune systems of insects of economic importance, as well as a variety of invertebrate disease vectors.

  14. Altered Toll-like receptor expression and function in HPV-associated oropharyngeal carcinoma

    PubMed Central

    Tobouti, Priscila Lie; Bolt, Robert; Radhakrishnan, Raghu; de Sousa, Suzana Cantanhede Orsini Machado; Hunter, Keith D.

    2018-01-01

    Toll-like receptors (TLRs) have been widely investigated due to their importance in the inflammatory response and possible links to tumor promotion/regression and prognosis. In cancers with an infective etiology, such as human papillomavirus (HPV)-associated Oropharyngeal Squamous Cell Carcinoma (OPSCC), TLR responses may be activated and play a role in tumorigenesis. Our aim was to assess the expression of all TLRs in OPSCC cell lines (both HPV+ and HPV–) by qPCR, Western Blot and flow cytometry and assess their response to TLR ligands lipopolysaccharide (LPS), LPS ultra-pure (LPS-UP) and peptidoglycan (PGN) by analyzing IL-8 and IL-6 production. We also immunostained 61 OPSCC tissue samples with anti-TLR4. Results showed lower TLR1 and TLR6 mRNA expression and higher TLR9 protein expression in HPV+ when compared to HPV–OPSCC cells. TLR4 expression did not vary by HPV status in OPSCC cells, but TLR4 expression was significantly lower in HPV+OPSCC tissues. After stimulation with PGN, only one cell line (HPV+) did not secrete IL-6 or IL-8. Furthermore, HPV+OPSCC lines showed no IL-6 or IL-8 production on treatment with LPS/LPS-UP. The data suggest changes in TLR4 signaling in HPV+OPSCC, since we have shown lower tissue expression of TLR4 and no pro-inflammatory response after stimulation with LPS and LPS-UP. Also, it suggests that OPSCC may respond to HPV infection by increased expression of TLR9. This study demonstrates differences in expression and function of TLRs in OPSCC, which are dependent on HPV status, and may indicate subversion of the innate immune response by HPV infection. PMID:29416610

  15. IgE Inhibits Toll-like Receptor 7- and Toll-like Receptor 9-Mediated Expression of Interferon-α by Plasmacytoid Dendritic Cells in Patients With Systemic Lupus Erythematosus.

    PubMed

    Khoryati, Liliane; Augusto, Jean-François; Shipley, Emilie; Contin-Bordes, Cécile; Douchet, Isabelle; Mitrovic, Stéphane; Truchetet, Marie-Elise; Lazaro, Estibaliz; Duffau, Pierre; Couzi, Lionel; Jacquemin, Clément; Barnetche, Thomas; Vacher, Pierre; Schaeverbeke, Thierry; Blanco, Patrick; Richez, Christophe

    2016-09-01

    Plasmacytoid dendritic cells (PDCs) play a central role in pathogenesis of systemic lupus erythematosus (SLE) through their unique ability to produce large amounts of type I interferon (IFN) upon Toll-like receptor 7 (TLR-7) and TLR-9 triggering. PDCs express specific surface regulatory receptors involved in negative regulation of IFNα secretion. These receptors use the γ-chain of high-affinity Fc receptor (FcR) for IgE, FcɛRI. We undertook this study to test our hypothesis that IgE engagement of FcɛRI on PDCs may impact IFNα production in SLE patients. Serum levels of total IgE were measured in healthy volunteers, SLE patients, and patients with IgE-dependent allergic disorders. FcɛRI expression on PDCs from SLE patients was evaluated by flow cytometry. Purified PDCs were incubated with monoclonal IgE for 24 hours, then stimulated for 18 hours with TLR agonists or immune complexes (ICs). IFNα production by PDCs was detected by quantitative real-time polymerase chain reaction (PCR) and enzyme-linked immunosorbent assay. Expression of TLR-7, TLR-9, and IFN regulatory factor 7 (IRF-7) in PDCs was quantified by quantitative real-time PCR. We observed significantly higher IgE levels in SLE patients with quiescent disease than in those with active disease. In SLE patients, IgE levels correlated inversely with disease activity. IgE levels were not associated with the presence of antinuclear IgE. Purified PDCs treated for 24 hours with monoclonal IgE up-regulated FcɛRI expression in an IgE dose-dependent manner. IgE-treated PDCs significantly decreased IFNα secretion and down-regulated CCR7 expression upon stimulation with TLR-7 and TLR-9 ligands and ICs from lupus patients. IgE treatment down-regulated expression of TLR-9 and IRF-7. Our results support the notion that IgE plays a protective role in SLE pathogenesis through the modulation of inflammatory response by PDCs. © 2016, American College of Rheumatology.

  16. Chronic exposure to indoxacarb and pulmonary expression of toll-like receptor-9 in mice

    PubMed Central

    Kaur, Sandeep; Mukhopadhyay, C. S.; Sethi, R. S.

    2016-01-01

    Aim: Chronic exposure to indoxacarb and pulmonary expression of toll-like receptor 9 (TLR-9) in mice. Materials and Methods: In this study, healthy male Swiss albino mice (n=30) aging 8-10 weeks were used to evaluate TLR-9 expression in lungs of mice following indoxacarb exposure with and without lipopolysaccharide (LPS). Indoxacarb was administered orally dissolved in groundnut oil at 4 and 2 mg/kg/day for 90 days. On day 91, five animals from each group were challenged with LPS/normal saline solution at 80 µg/animal. The lung tissues were processed for real time and immunohistochemical studies. Results: LPS resulted increase in fold change m-RNA expression level of TLR-9 as compare to control, while indoxacarb (4 mg/kg) alone and in combination with LPS resulted 16.21-fold change and 29.4-fold change increase in expression of TLR-9 m-RNA, respectively, as compared to control. Similarly, indoxacarb (2 mg/kg) alone or in combination with LPS also altered TLR-9 expression. Further at protein level control group showed minimal expression of TLR-9 in lungs as compare to other groups, however, LPS group showed intense positive staining in bronchial epithelium as well as in alveolar septal cells. Indoxacarb at both doses individually showed strong immuno-positive reaction as compare to control, however when combined with LPS resulted intense staining in airway epithelium as compare to control. Conclusion: Chronic oral administration of indoxacarb for 90 days (4 and 2 mg/kg) alters expression of TLR-9 at m-RNA and protein level and co-exposure with LPS exhibited synergistic effect. PMID:27956782

  17. No association of toll-like receptor 2 polymorphisms with Alzheimer's disease in Han Chinese.

    PubMed

    Yu, Jin-Tai; Sun, Yan-Ping; Ou, Jiang-Rong; Cui, Wei-Zhen; Zhang, Wei; Tan, Lan

    2011-10-01

    Toll-like receptor 2 (TLR2) represents a reasonable functional and positional candidate gene for Alzheimer's disease (AD) as it is located under the linkage region of AD on chromosome 4q, and is functionally involved in the microglia-mediated inflammatory response and amyloid β (Aβ) clearance. In the current study, 7 single nucleotide polymorphisms (SNPs) that span the TLR2 were selected and their associations with late-onset AD (LOAD) risk were assessed in a case-control sample comprising 785 individuals in a Han Chinese population. No significant differences in the frequency of TLR2 alleles, genotypes, and haplotypes in the AD cases were detected compared with the controls. TLR2 gene might not play a major role in the genetic predisposition to late-onset Alzheimer's disease in this population. Copyright © 2011 Elsevier Inc. All rights reserved.

  18. The active contribution of Toll-like receptors to allergic airway inflammation.

    PubMed

    Chen, Keqiang; Xiang, Yi; Yao, Xiaohong; Liu, Ying; Gong, Wanghua; Yoshimura, Teizo; Wang, Ji Ming

    2011-10-01

    Epithelia lining the respiratory tract represent a major portal of entry for microorganisms and allergens and are equipped with innate and adaptive immune signaling receptors for host protection. These include Toll-like receptors (TLRs) that recognize microbial components and evoke diverse responses in cells of the respiratory system. TLR stimulation by microorganism-derived molecules activates antigen presenting cells, control T helper (Th) 1, Th2, and Th17 immune cell differentiation, cytokine production by mast cells, and activation of eosinophils. It is clear that TLR are involved in the pathophysiology of allergic airway diseases such as asthma. Dendritic cells (DCs), a kind of antigen presenting cells, which play a key role in the induction of allergic airway inflammation, are privileged targets for pathogen associated molecular patterns (PAMPs). During the allergic responses, engagement of TLRs on DCs determines the Th2 polarization of the T cells. TLR signaling in mast cells increases the release of IL-5, and TLR activation of airway epithelial cells forces the generation of proallergic Th2 type of cytokines. Although these responses aim to protect the host, they may also result in inflammatory tissue damage in the airway. Under certain conditions, stimulation of TLRs, in particular, TLR9, may reduce Th2-dependent allergic inflammation by induction of Th1 responses. Therefore, understanding the complex regulatory roles of TLRs in the pathogenesis of allergic airway inflammation should facilitate the development of preventive and therapeutic measures for asthmatic patients. Copyright © 2011 Elsevier B.V. All rights reserved.

  19. Expression of toll-like receptors in hepatic cirrhosis and hepatocellular carcinoma.

    PubMed

    Sun, L; Dai, J J; Hu, W F; Wang, J

    2016-07-14

    Toll-like receptors (TLRs) can specifically identify pathogen-associated molecular patterns (PAMPs) by recognizing structural patterns in diverse microbial molecules, and can provide an effective defense against multiple microbial infectious. A variety of TLRs can be expressed on the surface of liver parenchymal as well as nonparenchymal cells. Kupffer cells are a type of hepatic nonparenchymal macrophage, and are positively associated with the severity of liver fibrosis. They play an important role in the synthesis and deposition of the extracellular matrix by upregulating the expression of tissue inhibitor of metalloproteinases and downregulating the activity of matrix metalloproteinases. Cirrhosis, a chronic diffuse lesion usually accompanying extensive liver fibrosis and nodular regeneration, is caused by liver parenchymal cells repeating injury-repair following reconstruction of organizational structure in the hepatic lobules. Hepatocellular carcinoma is caused by repeated and persistent chronic severe liver injury, and partial hepatocytes can eventually transform into hepatoma cells. Multiple TLRs such as TLR2, TLR3, TLR4, and TLR9, as well as other receptors, can be expressed in cirrhosis and hepatocellular carcinoma. About 53 and 85% of hepatocellular carcinoma patients frequently express TLR3 and TLR9, respectively. The chronic and repeated liver injury caused by alcohol, and HBV, HCV, or other pathogens can be recognized by TLRs through the PAMP pathway, which directly increases the risk for hepatic cirrhosis and hepatocellular carcinoma. In this review, we briefly present evidence that the novel cellular molecular mechanisms of TLRs may provide more information about new therapeutics targets of the anti-inflammatory immune response.

  20. Enhancement of islet engraftment and achievement of long-term islet allograft survival by Toll-like receptor 4 blockade.

    PubMed

    Giovannoni, Laurianne; Muller, Yannick D; Lacotte, Stéphanie; Parnaud, Géraldine; Borot, Sophie; Meier, Raphaël P H; Lavallard, Vanessa; Bédat, Benoît; Toso, Christian; Daubeuf, Bruno; Elson, Greg; Shang, Limin; Morel, Philippe; Kosco-Vilbois, Marie; Bosco, Domenico; Berney, Thierry

    2015-01-01

    Toll-like receptors are key players in sterile inflammation phenomena and can link the innate and adaptive immune systems by enhancing graft immunogenicity. They are also considered mediators of types 1 and 2 diabetes development. The aim of the present study was to assess the role of Toll-like receptor-4 (TLR4) in mediating the inflammatory and immune responses to pancreatic islets, thereby promoting inflammatory destruction and immune rejection of islet grafts. Experiments were conducted in murine and human in vitro systems and in vivo murine islet transplant models, using species-specific anti-TLR4 monoclonal antibodies. In vitro, mixed lymphocyte-islet reaction experiments were performed to assess T-cell activation and proliferation. In vivo, both a syngeneic (B6-to-B6) marginal mass islet transplant model to assess the impact of TLR4 blockade on islet engraftment and an allogeneic (DBA1-to-B6) model were used. In vitro TLR4 blockade decreased lipopolysaccharide-mediated β-cell apoptosis and T-cell activation and proliferation against allogeneic islets. In vivo, TLR4 blockade resulted in significantly better syngeneic marginal mass islet engraftment and in indefinite allogeneic islet graft survival. Tolerance was not observed because donor-specific skin graft rechallenge in nonrejecting animals resulted in rejection of both skin and islets, but without accelerated rejection as compared to naive animals. Taken together, our data indicate that TLR4 blockade leads to a significant improvement of syngeneic islet engraftment and of allogeneic islet graft survival. A mechanism of graft accommodation with concurrent inhibition of donor-specific immune memory is likely to be involved.

  1. Synthesis of Toll-like receptor 4 in Kupffer cells and its role in alcohol-induced liver disease.

    PubMed

    Zuo, Guoqing; Gong, Jianping; Liu, Chang'an; Wu, Chuanxin; Li, Shengwei; Dai, Lili

    2003-02-01

    To observe the synthesis of Toll-like receptor (TLR) 4 protein and its mRNA expression in Kupffer cells (KCs) and evaluate the role of TLR 4 in liver injury to rats through alcohol-induced liver disease. Twenty-eight Wistar rats were divided into two groups: ethanol-fed (group E) and control (group C). Group E rats were given ethanol at a dose of 5 - 12 g x kg(-1) x d(-1), while group C received dextrose. Animals from both groups were killed at 4 and 8 weeks. The KCs were isolated and synthesis of TLR 4 protein was determined by laser scanning confocal microscopy. TLR 4 mRNA expression in KCs was determined by reverse transcription polymerase chain reaction (RT-PCR) analysis. The levels of endotoxin, tumor necrosis factor-alpha (TNF-alpha) and interleukin-6 (IL-6) in plasma were determined. Changes in liver pathology were observed. Laser scanning confocal microscopy showed that the intensity of fluorescence of TLR 4 protein in group E was stronger than group C. Ethanol administration led to a significant increase in TLR 4 mRNA expression in group E compared with group C (P < 0.05). The concentrations of plasma endotoxin, TNF-alpha and IL-6 were higher in group E than in group C (P < 0.05). Liver sections from rats in group E demonstrated marked pathological changes. Ethanol administration can lead to the synthesis of TLR 4 protein and its gene expression in KCs, indicating that TLR 4 may play a major role in the development of alcohol-induced liver injury.

  2. Lipopolysaccharide (LPS)-binding protein stimulates CD14-dependent Toll-like receptor 4 internalization and LPS-induced TBK1-IKKϵ-IRF3 axis activation.

    PubMed

    Tsukamoto, Hiroki; Takeuchi, Shino; Kubota, Kanae; Kobayashi, Yohei; Kozakai, Sao; Ukai, Ippo; Shichiku, Ayumi; Okubo, Misaki; Numasaki, Muneo; Kanemitsu, Yoshitomi; Matsumoto, Yotaro; Nochi, Tomonori; Watanabe, Kouichi; Aso, Hisashi; Tomioka, Yoshihisa

    2018-05-14

    Toll-like receptor 4 (TLR4) is an indispensable immune receptor for lipopolysaccharide (LPS), a major component of the Gram-negative bacterial cell wall. Following LPS stimulation, TLR4 transmits the signal from the cell surface and becomes internalized in an endosome. However, the spatial regulation of TLR4 signaling is not fully understood. Here, we investigated the mechanisms of LPS-induced TLR4 internalization and clarified the roles of the extracellular LPS-binding molecules, LPS-binding protein (LBP), and glycerophosphatidylinositol-anchored protein (CD14). LPS stimulation of CD14-expressing cells induced TLR4 internalization in the presence of serum, and an inhibitory anti-LBP mAb blocked its internalization. Addition of LBP to serum-free cultures restored LPS-induced TLR4 internalization to comparable levels of serum. The secretory form of the CD14 (sCD14) induced internalization but required a much higher concentration than LBP. An inhibitory anti-sCD14 mAb was ineffective for serum-mediated internalization. LBP lacking the domain for LPS transfer to CD14 and a CD14 mutant with reduced LPS binding both attenuated TLR4 internalization. Accordingly, LBP is an essential serum molecule for TLR4 internalization, and its LPS transfer to membrane-anchored CD14 (mCD14) is a prerequisite. LBP induced the LPS-stimulated phosphorylation of TBK1, IKKϵ, and IRF3, leading to IFN-β expression. However, LPS-stimulated late activation of NFκB or necroptosis were not affected. Collectively, our results indicate that LBP controls LPS-induced TLR4 internalization, which induces TLR adaptor molecule 1 (TRIF)-dependent activation of the TBK1-IKKϵ-IRF3-IFN-β pathway. In summary, we showed that LBP-mediated LPS transfer to mCD14 is required for serum-dependent TLR4 internalization and activation of the TRIF pathway. Copyright © 2018, The American Society for Biochemistry and Molecular Biology.

  3. Cyclic GMP-dependent protein kinase II is necessary for macrophage M1 polarization and phagocytosis via toll-like receptor 2.

    PubMed

    Liao, Wei-Ting; You, Huey-Ling; Li, Changgui; Chang, Jan-Gowth; Chang, Shun-Jen; Chen, Chung-Jen

    2015-05-01

    Cyclic GMP-dependent protein kinase II (cGKII; PRKG2) phosphorylates a variety of biological targets and has been identified as a gout-susceptible gene. However, the regulatory role of cGKII in triggering gout disease has yet to be clarified. Thus, we plan to explore the specific function of cGKII in macrophages related to gout disease. By using cGKII gene knockdown method, we detected macrophage M1/M2 polarization, phagocytosis, and their responses to stimulation by monosodium urate (MSU). cGKII was highly expressed in M1 phenotype, but not in M2, and cGKII knockdown significantly inhibited macrophage M1 polarization by decreasing M1 chemokine markers (CXCL10 and CCL2) and downregulating phagocytosis function. We further identified that cGKII-associated phagocytosis was mediated by upregulating toll-like receptor 2 (TLR2) expression, but not by TLR4. Mimicking gout condition by MSU treatments, we found that MSU alone induced cGKII and TLR2 expression with increased M1 polarization markers and phagocytosis activity. It means that cGKII knockdown significantly inhibited this MSU-induced cGKII-TLR2-phagocytosis axis. Our study showed that cGKII plays a key role in M1 polarization, especially in TLR2-mediated phagocytosis under MSU exposure. The findings provide evidence for the possible role of cGKII as an inflammation exciter in gout disease. Gout-susceptible gene cGKII is necessary for macrophage M1 polarization. cGKII regulates M1 phagocytosis function via TLR2. Monosodium urate treatments increase cGKII expression and related function. This study reveals the role of cGKII in enhancing gouty inflammatory responses.

  4. Association of Toll-like receptor 3 and Toll-like receptor 9 single-nucleotide polymorphisms with hepatitis C virus persistence among Egyptians.

    PubMed

    Hamdy, Shaimaa; Osman, Ahmed M; Zakaria, Zainab A; Galal, Iman; Sobhy, Maha; Hashem, Mohamed; Allam, Walaa R; Abdel-Samiee, Mohamed; Rewisha, Eman; Waked, Imam; Abdelwahab, Sayed F

    2018-06-02

    Toll-like receptors (TLRs) give the innate immune system a considerable specificity for a large range of pathogens. TLR3 detects dsRNA of viruses while TLR9 recognizes bacterial and viral unmethylated CpG motifs. This study examined whether there is a potential association between single-nucleotide polymorphisms (SNPs) in the TLR3.rs3775290 (c.1377C/T), TLR9.rs5743836 (-1237T→C) and TLR9.rs352140 (G2848A) genes and HCV infection among Egyptian patients and healthcare workers (HCWs). We enrolled 546 subjects (409 HCWs and 137 patients) divided into four groups: group 1 included 265 seronegative, aviremic subjects; group 2 included 25 seronegative, viremic subjects; group 3 included 87 subjects with spontaneously resolved HCV infection; and group 4 included 169 chronic HCV patients. All subjects were genotyped for TLR3.rs3775290, TLR9.rs5743836 and TLR9.rs352140 SNPs by polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) analysis. TLR3.rs3775290 "CC" genotype was associated with chronic HCV infection, where there was a significantly greater frequency of this genotype among chronic patients when compared to subjects with spontaneously resolved infection (63.9% vs. 51.9%; p = 0.033; OR = 1.639 and 95% CI = 0.94-2.84). However, this SNP did not correlate with the HCV RNA load among the chronic subjects (p > 0.05). There was no significant difference in TLR9.rs5743836 and TLR9.rs352140 genotype distribution between groups (p > 0.05). Lack of association between the three SNPs was found, as the three SNPs are located on two different chromosomes. In conclusion, the TLR3.rs3775290 "CC" genotype was associated with HCV chronicity, while the TLR9 gene may not play a major role in HCV infection.

  5. Increased toll-like receptor 4 in cerebral endothelial cells contributes to the astrocyte swelling and brain edema in acute hepatic encephalopathy.

    PubMed

    Jayakumar, Arumugam R; Tong, Xiao Y; Curtis, Kevin M; Ruiz-Cordero, Roberto; Abreu, Maria T; Norenberg, Michael D

    2014-03-01

    Astrocyte swelling and the subsequent increase in intracranial pressure and brain herniation are major clinical consequences in patients with acute hepatic encephalopathy. We recently reported that conditioned media from brain endothelial cells (ECs) exposed to ammonia, a mixture of cytokines (CKs) or lipopolysaccharide (LPS), when added to astrocytes caused cell swelling. In this study, we investigated the possibility that ammonia and inflammatory agents activate the toll-like receptor 4 (TLR4) in ECs, resulting in the release of factors that ultimately cause astrocyte swelling. We found a significant increase in TLR4 protein expression when ECs were exposed to ammonia, CKs or LPS alone, while exposure of ECs to a combination of these agents potentiate such effects. In addition, astrocytes exposed to conditioned media from TLR4-silenced ECs that were treated with ammonia, CKs or LPS, resulted in a significant reduction in astrocyte swelling. TLR4 protein up-regulation was also detected in rat brain ECs after treatment with the liver toxin thioacetamide, and that thioacetamide-treated TLR4 knock-out mice exhibited a reduction in brain edema. These studies strongly suggest that ECs significantly contribute to the astrocyte swelling/brain edema in acute hepatic encephalopathy, likely as a consequence of increased TLR4 protein expression by blood-borne noxious agents. © 2013 International Society for Neurochemistry.

  6. Posttranslational Modification of HOIP Blocks Toll-Like Receptor 4-Mediated Linear-Ubiquitin-Chain Formation

    PubMed Central

    Bowman, James; Rodgers, Mary A.; Shi, Mude; Amatya, Rina; Hostager, Bruce; Iwai, Kazuhiro; Gao, Shou-Jiang

    2015-01-01

    ABSTRACT Linear ubiquitination is an atypical posttranslational modification catalyzed by the linear-ubiquitin-chain assembly complex (LUBAC), containing HOIP, HOIL-1L, and Sharpin. LUBAC facilitates NF-κB activation and inflammation upon receptor stimulation by ligating linear ubiquitin chains to critical signaling molecules. Indeed, linear-ubiquitination-dependent signaling is essential to prevent pyogenic bacterial infections that can lead to death. While linear ubiquitination is essential for intracellular receptor signaling upon microbial infection, this response must be measured and stopped to avoid tissue damage and autoimmunity. While LUBAC is activated upon bacterial stimulation, the mechanisms regulating LUBAC activity in response to bacterial stimuli have remained elusive. We demonstrate that LUBAC activity itself is downregulated through ubiquitination, specifically, ubiquitination of the catalytic subunit HOIP at the carboxyl-terminal lysine 1056. Ubiquitination of Lys1056 dynamically altered HOIP conformation, resulting in the suppression of its catalytic activity. Consequently, HOIP Lys1056-to-Arg mutation led not only to persistent LUBAC activity but also to prolonged NF-κB activation induced by bacterial lipopolysaccharide-mediated Toll-like receptor 4 (TLR4) stimulation, whereas it showed no effect on NF-κB activation induced by CD40 stimulation. This study describes a novel posttranslational regulation of LUBAC-mediated linear ubiquitination that is critical for specifically directing TLR4-mediated NF-κB activation. PMID:26578682

  7. Human esophageal myofibroblasts secrete proinflammatory cytokines in response to acid and Toll-like receptor 4 ligands

    PubMed Central

    Gargus, Matthew; Niu, Chao; Vallone, John G.; Binkley, Jana; Rubin, Deborah C.

    2015-01-01

    The pathophysiology of esophageal injury, repair, and inflammation in gastroesophageal reflux-disease (GERD) is complex. Whereas most studies have focused on the epithelial response to GERD injury, we are interested in the stromal response. We hypothesized that subepithelial esophageal myofibroblasts in GERD secrete proinflammatory cytokines in response to injurious agents encountered via epithelial barrier breaches or through dilated epithelial intercellular spaces. We determined the percentage of myofibroblasts [α-smooth muscle actin (α-SMA)+vimentin+CD31−] in the subepithelial GERD and normal esophageal stroma by immunomorphologic analysis. We performed α-SMA coimmunostaining with IL-6 and p65. We established and characterized primary cultures of α-SMA+vimentin+CD31−CD45− human esophageal myofibroblasts (HuEso MFs). We modeled GERD by treatment with pH 4.5-acidified media and Toll-like receptor 4 (TLR4) ligands, LPS and high-mobility group box 1 protein (HMGB1), and determined myofibroblast cytokine secretion in response to GERD injury. We demonstrate that spindle-shaped cell myofibroblasts are located near the basement membrane of stratified squamous epithelium in normal esophagus. We identify an increase in subepithelial myofibroblasts and activation of proinflammatory pathways in patients with GERD. Primary cultures of stromal cells obtained from normal esophagus retain myofibroblast morphology and express the acid receptor transient receptor potential channel vanilloid subfamily 1 (TRPV1) and TLR4. HuEso MFs stimulated with acid and TLR4 agonists LPS and HMGB1 increase IL-6 and IL-8 secretion via TRPV1 and NF-κB activation. Our work implicates a role for human subepithelial stromal cells in the pathogenesis of GERD-related esophageal injury. Findings of this study can be extended to the investigation of epithelial-stromal interactions in inflammatory esophageal mucosal disorders. PMID:25882613

  8. Toll-like receptor agonists are potent inhibitors of human immunodeficiency virus-type 1 replication in peripheral blood mononuclear cells.

    PubMed

    Buitendijk, Maarten; Eszterhas, Susan K; Howell, Alexandra L

    2014-05-01

    Innate immune responses to microbial pathogens are initiated following the binding of ligand to specific pattern recognition receptors. Each pattern recognition receptor, which includes members of the Toll-like receptor (TLR) family, is specific for a particular type of pathogen associated molecular pattern ensuring that the organism can respond rapidly to a wide range of pathogens including bacteria, viruses, and fungi. We studied the extent to which agonists to endosomal TLR could induce anti-HIV-1 activity in peripheral blood mononuclear cells (PBMCs). When agonists to TLR3, TLR7, TLR8 and TLR9 were added prior to infection with HIV-1, they significantly reduced infection of peripheral blood mononuclear cells. Interestingly, agonists to TLR8 and TLR9 were highly effective at blocking HIV replication even when added as late as 48 h or 72 h, respectively, after HIV-1 infection, indicating that the anti-viral effect was durable and long lasting. Analysis of the induction of anti-viral genes after agonist activation of TLR indicated that all of the agonists induced expression of the type I interferons and interferon stimulated genes, although to variable levels that depended on the agonist used. Interestingly, only the agonist to TLR9, ODN2395 DNA, induced expression of type II interferon and the anti-HIV proteins Apobec3G and SAMHD1. By blocking TLR activity using an inhibitor to the MyD88 adaptor protein, we demonstrated that, at least for TLR8 and TLR9, the anti-HIV activity was not entirely mediated by TLR activation, but likely by the activation of additional anti-viral sensors in HIV target cells. These findings suggest that agonists to the endosomal TLR function to induce expression of anti-HIV molecules by both TLR-mediated and non-TLR-mediated mechanisms. Moreover, the non-TLR-mediated mechanisms induced by these agonists could potentially be exploited to block HIV-1 replication in recently HIV-exposed individuals.

  9. Involvement of suppressors of cytokine signaling in toll-like receptor-mediated block of dendritic cell differentiation.

    PubMed

    Bartz, Holger; Avalos, Nicole M; Baetz, Andrea; Heeg, Klaus; Dalpke, Alexander H

    2006-12-15

    Dendritic cells (DCs) are important sentinels within innate immunity, monitoring the presence of infectious microorganisms. They operate in 2 different maturation stages, with transition from immature to mature DCs being induced by activation of toll-like receptors (TLRs). However, TLRs are also expressed on precursor cells of DCs. Here we analyzed the effects of TLR stimulation during the process of granulocyte-macrophage-colony-stimulating factor (GM-CSF)-mediated in vitro generation of immature DCs from precursor cells. We show that TLR triggering deviated phenotypic and functional differentiation from CD14+ monocytes to CD1a+ DCs. Similar results were obtained when differentiation of murine myeloid DCs from bone marrow cells was analyzed. The inhibitory effects were independent of soluble factors. TLR stimulation in DC precursor cells induced proteins of the suppressor of cytokine signaling family (SOCS), which correlated with loss of sensitivity to GM-CSF. Overexpression of SOCS-1 abolished GM-CSF signal transduction. Moreover, forced SOCS-1 expression in DC precursors mimicked the inhibitory effects on DC generation observed for TLR stimulation. The results indicate that TLR stimulation during the period of DC generation interferes with and deviates DC differentiation and that these effects are mediated particularly by SOCS-1.

  10. Bacterium-Induced CXCL10 Secretion by Osteoblasts Can Be Mediated in Part through Toll-Like Receptor 4

    PubMed Central

    Gasper, Nancy A.; Petty, Cynthia C.; Schrum, Laura W.; Marriott, Ian; Bost, Kenneth L.

    2002-01-01

    Two common pathogens known to cause bone infection, Salmonella and Staphylococcus aureus, were investigated to determine their abilities to induce chemokine expression in cultured mouse and human osteoblasts. While these cells are responsible for bone formation, we were surprised to find that they could respond to bacterial infection by upregulating expression of the chemokine CXCL10 (IP-10). However, there were significant differences in the abilities of the gram-negative bacterium Salmonella and the gram-positive bacterium S. aureus to induce expression of CXCL10. Reverse transcription-PCR and enzyme-linked immunosorbent assay analyses showed high levels of Salmonella-induced CXCL10 mRNA and protein expression, respectively, whereas the osteoblast response to S. aureus was significantly less. Consistent with these findings, Salmonella-derived lipopolysaccharide (LPS), but not S. aureus-derived peptidoglycan, could induce expression of CXCL10. An antibody against toll-like receptor 4 (TLR4) could block the LPS-induced CXCL10 production, demonstrating the functional expression of TLR4 by osteoblasts. Despite the inducible nature of TLR2 mRNA expression by bacterium-infected osteoblasts, peptidoglycan failed to stimulate CXCL10 secretion. Immunofluorescent staining of bacterium-infected calvaria (i.e., skull bone) demonstrated the presence of CXCL10 in osteoblasts. The fact that osteoblasts did not express CXCR3 mRNA, whereas T lymphocytes can express high levels of this receptor, suggests that osteoblast-derived CXCL10 may recruit T lymphocytes to the sites of bone infections. PMID:12117914

  11. Ocean acidification weakens the immune response of blood clam through hampering the NF-kappa β and toll-like receptor pathways.

    PubMed

    Liu, Saixi; Shi, Wei; Guo, Cheng; Zhao, Xinguo; Han, Yu; Peng, Chao; Chai, Xueliang; Liu, Guangxu

    2016-07-01

    The impact of pCO2 driven ocean acidification on marine bivalve immunity remains poorly understood. To date, this impact has only been investigated in a few bivalve species and the underlying molecular mechanism remains unknown. In the present study, the effects of the realistic future ocean pCO2 levels (pH at 8.1, 7.8, and 7.4) on the total number of haemocyte cells (THC), phagocytosis status, blood cell types composition, and expression levels of twelve genes from the NF-kappa β signaling and toll-like receptor pathways of a typical bottom burrowing bivalve, blood clam (Tegillarca granosa), were investigated. The results obtained showed that while both THC number and phagocytosis frequency were significantly reduced, the percentage of red and basophil granulocytes were significantly decreased and increased, respectively, upon exposure to elevated pCO2. In addition, exposure to pCO2 acidified seawater generally led to a significant down-regulation in the inducer and key response genes of NF-kappa β signaling and toll-like receptor pathways. The results of the present study revealed that ocean acidification may hamper immune responses of the bivalve T. granosa which subsequently render individuals more susceptible to pathogens attacks such as those from virus and bacteria. Copyright © 2016 Elsevier Ltd. All rights reserved.

  12. Toll-like receptor-mediated responses of primary intestinal epithelial cells during the development of colitis.

    PubMed

    Singh, Joy Carmelina Indira; Cruickshank, Sheena Margaret; Newton, Darren James; Wakenshaw, Louise; Graham, Anne; Lan, Jinggang; Lodge, Jeremy Peter Alan; Felsburg, Peter John; Carding, Simon Richard

    2005-03-01

    The interleukin-2-deficient (IL-2(-/-)) mouse model of ulcerative colitis was used to test the hypothesis that colonic epithelial cells (CEC) directly respond to bacterial antigens and that alterations in Toll-like receptor (TLR)-mediated signaling may occur during the development of colitis. TLR expression and activation of TLR-mediated signaling pathways in primary CEC of healthy animals was compared with CEC in IL-2(-/-) mice during the development of colitis. In healthy animals, CEC expressed functional TLR, and in response to the TLR4 ligand LPS, proliferated and secreted the cytokines IL-6 and monocyte chemoattractant protein-1 (MCP-1). However, the TLR-responsiveness of CEC in IL-2(-/-) mice was different with decreased TLR4 responsiveness and augmented TLR2 responses that result in IL-6 and MCP-1 secretion. TLR signaling in CEC did not involve NF-kappaB (p65) activation with the inhibitory p50 form of NF-kappaB predominating in CEC in both the healthy and inflamed colon. Development of colitis was, however, associated with the activation of MAPK family members and upregulation of MyD88-independent signaling pathways characterized by increased caspase-1 activity and IL-18 production. These findings identify changes in TLR expression and signaling during the development of colitis that may contribute to changes in the host response to bacterial antigens seen in colitis.

  13. Invasive Streptococcus mutans induces inflammatory cytokine production in human aortic endothelial cells via regulation of intracellular toll-like receptor 2 and nucleotide-binding oligomerization domain 2.

    PubMed

    Nagata, E; Oho, T

    2017-04-01

    Streptococcus mutans, the primary etiologic agent of dental caries, can gain access to the bloodstream and has been associated with cardiovascular disease. However, the roles of S. mutans in inflammation in cardiovascular disease remain unclear. The aim of this study was to examine cytokine production induced by S. mutans in human aortic endothelial cells (HAECs) and to evaluate the participation of toll-like receptors (TLRs) and cytoplasmic nucleotide-binding oligomerization domain (NOD) -like receptors in HAECs. Cytokine production by HAECs was determined using enzyme-linked immunosorbent assays, and the expression of TLRs and NOD-like receptors was evaluated by real-time polymerase chain reaction, flow cytometry and immunocytochemistry. The involvement of TLR2 and NOD2 in cytokine production by invaded HAECs was examined using RNA interference. The invasion efficiencies of S. mutans strains were evaluated by means of antibiotic protection assays. Five of six strains of S. mutans of various serotypes induced interleukin-6, interleukin-8 and monocyte chemoattractant protein-1 production by HAECs. All S. mutans strains upregulated TLR2 and NOD2 mRNA levels in HAECs. Streptococcus mutans Xc upregulated the intracellular TLR2 and NOD2 protein levels in HAECs. Silencing of the TLR2 and NOD2 genes in HAECs invaded by S. mutans Xc led to a reduction in interleukin-6, interleukin-8 and monocyte chemoattractant protein-1 production. Cytokine production induced by invasive S. mutans via intracellular TLR2 and NOD2 in HAECs may be associated with inflammation in cardiovascular disease. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  14. Molecular analysis of a novel Toll/interleukin-1 receptor (TIR)-domain containing virulence protein of Y. pseudotuberculosis among Far East scarlet-like fever serotype I strains.

    PubMed

    Nörenberg, Dominik; Wieser, Andreas; Magistro, Giuseppe; Hoffmann, Christiane; Meyer, Christian; Messerer, Maxim; Schubert, Sören

    2013-12-01

    Pathogenicity of Yersinia pseudotuberculosis is determined by an arsenal of virulence factors. Particularly, the Yersinia outer proteins (Yops) and the Type III secretion system (T3SS) encoded on the pYV virulence plasmid are required for Yersinia pathogenicity. A specific group of Y. pseudotuberculosis, responsible for the clinical syndrome described as Far East scarlet-like fever (FESLF), is known to have an altered virulence gene cluster. Far East strains cause unique clinical symptoms for which the pYV virulence plasmid plays apparently a rather secondary role. Here, we characterize a previously unknown protein of Y. pseudotuberculosis serotype I strains (TcpYI) which can be found particularly among the FESLF strain group. The TcpYI protein shares considerable sequence homology to members of the Toll/IL-1 receptor family. Bacterial TIR domain containing proteins (Tcps) interact with the innate immune system by TIR-TIR interactions and subvert host defenses via individual, multifaceted mechanisms. In terms of virulence, it appears that the TcpYI protein of Y. pseudotuberculosis displays its own virulence phenotype compared to the previously characterized bacterial Tcps. Our results clearly demonstrate that TcpYI increases the intracellular survival of the respective strains in vitro. Furthermore, we show here that the intracellular survival benefit of the wild-type strain correlates with an increase in tcpYI gene expression inside murine macrophages. In support of this, we found that TcpYI enhances the survival inside the spleens of mice in a mouse model of peritonitis. Our results may point toward involvement of the TcpYI protein in inhibition of phagocytosis, particularly in distinct Y. pseudotuberculosis strains of the FESLF strain group where the pYV virulence plasmid is absent. Copyright © 2013 Elsevier GmbH. All rights reserved.

  15. Ebola virus-like particles stimulate type I interferons and proinflammatory cytokine expression through the toll-like receptor and interferon signaling pathways.

    PubMed

    Ayithan, Natarajan; Bradfute, Steven B; Anthony, Scott M; Stuthman, Kelly S; Dye, John M; Bavari, Sina; Bray, Mike; Ozato, Keiko

    2014-02-01

    Ebola viruses (EBOV) can cause severe hemorrhagic disease with high case fatality rates. Currently, no vaccines or therapeutics are approved for use in humans. Ebola virus-like particles (eVLP) comprising of virus protein (VP40), glycoprotein, and nucleoprotein protect rodents and nonhuman primates from lethal EBOV infection, representing as a candidate vaccine for EBOV infection. Previous reports have shown that eVLP stimulate the expression of proinflammatory cytokines in dendritic cells (DCs) and macrophages (MΦs) in vitro. However, the molecular mechanisms and signaling pathways through which eVLP induce innate immune responses remain obscure. In this study, we show that eVLP stimulate not only the expression of proinflammatory cytokines but also the expression of type I interferons (IFNs) and IFN-stimulated genes (ISGs) in murine bone marrow-derived DCs (BMDCs) and MΦs. Our data indicate that eVLP trigger host responses through toll-like receptor (TLR) pathway utilizing 2 distinct adaptors, MyD88 and TRIF. More interestingly, eVLP activated the IFN signaling pathway by inducing a set of potent antiviral ISGs. Last, eVLP and synthetic adjuvants, Poly I:C and CpG DNA, cooperatively increased the expression of cytokines and ISGs. Further supporting this synergy, eVLP when administered together with Poly I:C conferred mice enhanced protection against EBOV infection. These results indicate that eVLP stimulate early innate immune responses through TLR and type I IFN signaling pathways to protect the host from EBOV infection.

  16. Evidence that opioids may have toll-like receptor 4 and MD-2 effects.

    PubMed

    Hutchinson, Mark R; Zhang, Yingning; Shridhar, Mitesh; Evans, John H; Buchanan, Madison M; Zhao, Tina X; Slivka, Peter F; Coats, Benjamen D; Rezvani, Niloofar; Wieseler, Julie; Hughes, Travis S; Landgraf, Kyle E; Chan, Stefanie; Fong, Stephanie; Phipps, Simon; Falke, Joseph J; Leinwand, Leslie A; Maier, Steven F; Yin, Hang; Rice, Kenner C; Watkins, Linda R

    2010-01-01

    Opioid-induced proinflammatory glial activation modulates wide-ranging aspects of opioid pharmacology including: opposition of acute and chronic opioid analgesia, opioid analgesic tolerance, opioid-induced hyperalgesia, development of opioid dependence, opioid reward, and opioid respiratory depression. However, the mechanism(s) contributing to opioid-induced proinflammatory actions remains unresolved. The potential involvement of toll-like receptor 4 (TLR4) was examined using in vitro, in vivo, and in silico techniques. Morphine non-stereoselectively induced TLR4 signaling in vitro, blocked by a classical TLR4 antagonist and non-stereoselectively by naloxone. Pharmacological blockade of TLR4 signaling in vivo potentiated acute intrathecal morphine analgesia, attenuated development of analgesic tolerance, hyperalgesia, and opioid withdrawal behaviors. TLR4 opposition to opioid actions was supported by morphine treatment of TLR4 knockout mice, which revealed a significant threefold leftward shift in the analgesia dose response function, versus wildtype mice. A range of structurally diverse clinically-employed opioid analgesics was found to be capable of activating TLR4 signaling in vitro. Selectivity in the response was identified since morphine-3-glucuronide, a morphine metabolite with no opioid receptor activity, displayed significant TLR4 activity, whilst the opioid receptor active metabolite, morphine-6-glucuronide, was devoid of such properties. In silico docking simulations revealed ligands bound preferentially to the LPS binding pocket of MD-2 rather than TLR4. An in silico to in vitro prediction model was built and tested with substantial accuracy. These data provide evidence that select opioids may non-stereoselectively influence TLR4 signaling and have behavioral consequences resulting, in part, via TLR4 signaling.

  17. Identification of Novel Synthetic Toll-like Receptor 2 Agonists by High Throughput Screening*

    PubMed Central

    Guan, Yue; Omueti-Ayoade, Katherine; Mutha, Sarita K.; Hergenrother, Paul J.; Tapping, Richard I.

    2010-01-01

    Toll-like receptors (TLRs) play a central role in host defense by inducing inflammatory and adaptive immune responses following infection. Drugs that target TLRs are of considerable interest as potential inflammatory regulators, vaccine adjuvants, and novel immunotherapeutics. TLR2, in cooperation with either TLR1 or TLR6, mediates responses to a wide variety of microbial products as well as products of host tissue damage. In an effort to understand the structural basis of TLR2 recognition and uncover novel TLR2 agonists, a synthetic chemical library of 24,000 compounds was screened using an IL-8-driven luciferase reporter in cells expressing these human receptors. The screening yielded several novel TLR2-dependent activators that utilize TLR1, TLR6, or both as co-receptors. These novel small molecule compounds are aromatic in nature and structurally unrelated to any known TLR2 agonists. The three most potent compounds do not exhibit synergistic activity, nor do they act as pseudoantagonists toward natural TLR2 activators. Interestingly, two of the compounds exhibit species specificity and are inactive toward murine peritoneal macrophages. Mutational analysis reveals that although the central extracellular region of TLR1 is required for stimulation, there are subtle differences in the mechanism of stimulation mediated by the synthetic compounds in comparison with natural lipoprotein agonists. The three most potent compounds activate cells in the nanomolar range and stimulate cytokine production from human peripheral blood monocytes. Our results confirm the utility of high throughput screens to uncover novel synthetic TLR2 agonists that may be of therapeutic benefit. PMID:20504771

  18. Role of a transductional-transcriptional processor complex involving MyD88 and IRF-7 in Toll-like receptor signaling

    PubMed Central

    Honda, Kenya; Yanai, Hideyuki; Mizutani, Tatsuaki; Negishi, Hideo; Shimada, Naoya; Suzuki, Nobutaka; Ohba, Yusuke; Takaoka, Akinori; Yeh, Wen-Chen; Taniguchi, Tadatsugu

    2004-01-01

    Toll-like receptor (TLR) activation is central to immunity, wherein the activation of the TLR9 subfamily members TLR9 and TLR7 results in the robust induction of type I IFNs (IFN-α/β) by means of the MyD88 adaptor protein. However, it remains unknown how the TLR signal “input” can be processed through MyD88 to “output” the induction of the IFN genes. Here, we demonstrate that the transcription factor IRF-7 interacts with MyD88 to form a complex in the cytoplasm. We provide evidence that this complex also involves IRAK4 and TRAF6 and provides the foundation for the TLR9-dependent activation of the IFN genes. The complex defined in this study represents an example of how the coupling of the signaling adaptor and effector kinase molecules together with the transcription factor regulate the processing of an extracellular signal to evoke its versatile downstream transcriptional events in a cell. Thus, we propose that this molecular complex may function as a cytoplasmic transductional-transcriptional processor. PMID:15492225

  19. Conservation of Toll-like receptor signaling pathways in teleost fish

    USGS Publications Warehouse

    Purcell, M.K.; Smith, K.D.; Aderem, A.; Hood, L.; Winton, J.R.; Roach, J.C.

    2006-01-01

    In mammals, toll-like receptors (TLR) recognize ligands, including pathogen-associated molecular patterns (PAMPs), and respond with ligand-specific induction of genes. In this study, we establish evolutionary conservation in teleost fish of key components of the TLR-signaling pathway that act as switches for differential gene induction, including MYD88, TIRAP, TRIF, TRAF6, IRF3, and IRF7. We further explore this conservation with a molecular phylogenetic analysis of MYD88. To the extent that current genomic analysis can establish, each vertebrate has one ortholog to each of these genes. For molecular tree construction and phylogeny inference, we demonstrate a methodology for including genes with only partial primary sequences without disrupting the topology provided by the high-confidence full-length sequences. Conservation of the TLR-signaling molecules suggests that the basic program of gene regulation by the TLR-signaling pathway is conserved across vertebrates. To test this hypothesis, leukocytes from a model fish, rainbow trout (Oncorhynchus mykiss), were stimulated with known mammalian TLR agonists including: diacylated and triacylated forms of lipoprotein, flagellin, two forms of LPS, synthetic double-stranded RNA, and two imidazoquinoline compounds (loxoribine and R848). Trout leukocytes responded in vitro to a number of these agonists with distinct patterns of cytokine expression that correspond to mammalian responses. Our results support the key prediction from our phylogenetic analyses that strong selective pressure of pathogenic microbes has preserved both TLR recognition and signaling functions during vertebrate evolution.

  20. B cell Toll-like receptors and immunoglobulin class-switch DNA recombination

    PubMed Central

    Pone, Egest J.; Xu, Zhenming; White, Clayton A.; Zan, Hong; Casali, Paolo

    2014-01-01

    Toll-like receptors (TLRs) are a family of conserved pattern recognition receptors (PRRs). Engagement of TLRs in B cells by microbe-associated molecular patterns (MAMPs) induces T-independent (TI) antibody responses and plays an important role in the early stages of T-dependent (TD) antibody responses before specific T cell help becomes available, in part by facilitating B cell entry into the germinal center reaction. The role of B cell TLRs in the antibody response is magnified by the synergy of B cell receptor (BCR) crosslinking and TLR engagement in promoting B cell proliferation and efficiently inducing immunoglobulin (Ig) class switch DNA recombination (CSR), which crucially diversifies the antibody biological effector functions. Dual engagement of TLRs and BCR can be mediated by complex MAMPs such as lipopolysaccharides (LPS), which engages TLR4 through its lipid A moiety and crosslinks the BCR through its polysaccharidic moiety (O-antigen). Dual BCR/TLR engagement induces CSR to all Ig isotypes, as directed by different cytokines, while engagement of any TLR alone induces only marginal CSR. Integration of BCR and TLR signaling results in activation of the canonical and non-canonical NF-κB pathways, induction of activation-induced cytidine deaminase (AID) and germline transcription of switch (S) regions in the IgH locus. The last two are essential events for CSR to unfold. A critical role of dual BCR/TLR engagement in induction of CSR and generation of neutralizing antibodies is emphasized by the emergence of TLR ligands as integral components of vaccines that greatly boost humoral immunity in a B cell-intrinsic fashion. Further, dual BCR/TLR engagement by complex self-antigens will result in dysregulation of AID expression and CSR in autoreactive B cells, leading to generation of isotype-switched pathogenic autoantibodies. Finally, an important aspect of dual BCR/TLR engagement is the boosting of specific antibody response to tumor antigens, as suggested by

  1. Pregnane X Receptor Regulates Pathogen-Induced Inflammation and Host Defense against an Intracellular Bacterial Infection through Toll-like Receptor 4.

    PubMed

    Qiu, Zhijuan; Cervantes, Jorge L; Cicek, Basak B; Mukherjee, Subhajit; Venkatesh, Madhukumar; Maher, Leigh A; Salazar, Juan C; Mani, Sridhar; Khanna, Kamal M

    2016-08-23

    The nuclear pregnane X receptor (PXR) plays a central role in regulating xenobiotic metabolism. We now report a novel role for PXR as a critical negative regulator of innate immunity after infection. Pxr(-/-) mice exhibited remarkably elevated pro-inflammatory cytokine and chemokine production following infection with Listeria monocytogenes (Lm). Despite the more robust innate immune response, Pxr(-/-) mice were highly susceptible to Lm infection. Surprisingly, disruption of the Toll-like receptor 4 (TLR4) but not TLR2 signaling restored the inflammation to normal levels and the ability to clear Lm in Pxr(-/-) mice. Mechanistically, the heightened inflammation in Pxr(-/-) mice resulted in the death of inflammatory monocytes that led to the enhanced susceptibility to Lm infection. These data demonstrated that PXR regulated pathogen-induced inflammation and host defense against Lm infection through modulating the TLR4 pathway. In summary, we discovered an apical role for PXR in regulating innate immunity. In addition, we uncovered a remarkable negative impact of the TLR4 pathway in controlling the quality of the inflammatory response and host defense against a gram-positive bacterial infection.

  2. Comparative genomics of Toll-like receptor signalling in five species

    PubMed Central

    Jann, Oliver C; King, Annemarie; Corrales, Nestor Lopez; Anderson, Susan I; Jensen, Kirsty; Ait-ali, Tahar; Tang, Haizhou; Wu, Chunhua; Cockett, Noelle E; Archibald, Alan L; Glass, Elizabeth J

    2009-01-01

    Background Over the last decade, several studies have identified quantitative trait loci (QTL) affecting variation of immune related traits in mammals. Recent studies in humans and mice suggest that part of this variation may be caused by polymorphisms in genes involved in Toll-like receptor (TLR) signalling. In this project, we used a comparative approach to investigate the importance of TLR-related genes in comparison with other immunologically relevant genes for resistance traits in five species by associating their genomic location with previously published immune-related QTL regions. Results We report the genomic localisation of TLR1-10 and ten associated signalling molecules in sheep and pig using in-silico and/or radiation hybrid (RH) mapping techniques and compare their positions with their annotated homologues in the human, cattle and mouse whole genome sequences. We also report medium-density RH maps for porcine chromosomes 8 and 13. A comparative analysis of the positions of previously published relevant QTLs allowed the identification of homologous regions that are associated with similar health traits in several species and which contain TLR related and other immunologically relevant genes. Additional evidence was gathered by examining relevant gene expression and association studies. Conclusion This comparative genomic approach identified eight genes as potentially causative genes for variations of health related traits. These include susceptibility to clinical mastitis in dairy cattle, general disease resistance in sheep, cattle, humans and mice, and tolerance to protozoan infection in cattle and mice. Four TLR-related genes (TLR1, 6, MyD88, IRF3) appear to be the most likely candidate genes underlying QTL regions which control the resistance to the same or similar pathogens in several species. Further studies are required to investigate the potential role of polymorphisms within these genes. PMID:19432955

  3. A20-binding inhibitor of NF-κB (ABIN1) controls Toll-like receptor-mediated CCAAT/enhancer-binding protein β activation and protects from inflammatory disease.

    PubMed

    Zhou, Jingran; Wu, Ruiqiong; High, Anthony A; Slaughter, Clive A; Finkelstein, David; Rehg, Jerold E; Redecke, Vanessa; Häcker, Hans

    2011-11-01

    Toll-like receptors (TLRs) are expressed on innate immune cells and trigger inflammation upon detection of pathogens and host tissue injury. TLR-mediated proinflammatory-signaling pathways are counteracted by partially characterized anti-inflammatory mechanisms that prevent exaggerated inflammation and host tissue damage as manifested in inflammatory diseases. We biochemically identified a component of TLR-signaling pathways, A20-binding inhibitor of NF-κB (ABIN1), which recently has been linked by genome-wide association studies to the inflammatory diseases systemic lupus erythematosus and psoriasis. We generated ABIN1-deficient mice to study the function of ABIN1 in vivo and during TLR activation. Here we show that ABIN1-deficient mice develop a progressive, lupus-like inflammatory disease characterized by expansion of myeloid cells, leukocyte infiltrations in different parenchymatous organs, activated T and B lymphocytes, elevated serum Ig levels, and the appearance of autoreactive antibodies. Kidneys develop glomerulonephritis and proteinuria, reflecting tissue injury. Surprisingly, ABIN1-deficient macrophages exhibit normal regulation of major proinflammatory signaling pathways and mediators but show selective deregulation of the transcription factor CCAAT/enhancer binding protein β (C/EBPβ) and its target genes, such as colony-stimulating factor 3 (Csf3), nitric oxide synthase, inducible (Nos2), and S100 calcium-binding protein A8 (S100a8). Their gene products, which are intimately linked to innate immune cell expansion (granulocyte colony-stimulating factor), cytotoxicity (inducible nitric oxide synthase), and host factor-derived inflammation (S100A8), may explain, at least in part, the inflammatory phenotype observed. Together, our data reveal ABIN1 as an essential anti-inflammatory component of TLR-signaling pathways that controls C/EBPβ activity.

  4. Toll-like receptors 2 and 4 modulate intestinal IL-10 differently in ileum and colon

    PubMed Central

    Layunta, Elena; Grasa, Laura; Pardo, Julián; García, Santiago; Alcalde, Ana I

    2017-01-01

    Background Inflammatory bowel diseases are consequence of an intestinal homeostasis breakdown in which innate immune dysregulation is implicated. Toll-like receptor (TLR)2 and TLR4 are immune recognition receptors expressed in the intestinal epithelium, the first physical-physiological barrier for microorganisms, to inform the host of the presence of Gram-positive and Gram-negative organisms. Interleukin (IL)-10 is an essential anti-inflammatory cytokine that contributes to maintenance of intestinal homeostasis. Aim Our main aim was to investigate intestinal IL-10 synthesis and release, and whether TLR2 and TLR4 are determinants of IL-10 expression in the intestinal tract. Methods We used Caco-2 cell line as an enterocyte-like cell model, and also ileum and colon from mice deficient in TLR2, TLR4 or TLR2/4 to test the involvement of TLR signaling. Results Intestinal epithelial cells are able to synthesize and release IL-10 and their expression is increased after TLR2 or TLR4 activation. IL-10 regulation seems to be tissue specific, with IL-10 expression in the ileum regulated by a compensation between TLR2 and TLR4 expression, whereas in the colon, TLR2 and TLR4 affect IL-10 expression independently. Conclusions Intestinal epithelial cells could release IL-10 in response to TLR activation, playing an intestinal tissue-dependent and critical intestinal immune role. PMID:29774159

  5. Toll-like receptors 2 and 4 modulate intestinal IL-10 differently in ileum and colon.

    PubMed

    Latorre, Eva; Layunta, Elena; Grasa, Laura; Pardo, Julián; García, Santiago; Alcalde, Ana I; Mesonero, José E

    2018-04-01

    Inflammatory bowel diseases are consequence of an intestinal homeostasis breakdown in which innate immune dysregulation is implicated. Toll-like receptor (TLR)2 and TLR4 are immune recognition receptors expressed in the intestinal epithelium, the first physical-physiological barrier for microorganisms, to inform the host of the presence of Gram-positive and Gram-negative organisms. Interleukin (IL)-10 is an essential anti-inflammatory cytokine that contributes to maintenance of intestinal homeostasis. Our main aim was to investigate intestinal IL-10 synthesis and release, and whether TLR2 and TLR4 are determinants of IL-10 expression in the intestinal tract. We used Caco-2 cell line as an enterocyte-like cell model, and also ileum and colon from mice deficient in TLR2, TLR4 or TLR2/4 to test the involvement of TLR signaling. Intestinal epithelial cells are able to synthesize and release IL-10 and their expression is increased after TLR2 or TLR4 activation. IL-10 regulation seems to be tissue specific, with IL-10 expression in the ileum regulated by a compensation between TLR2 and TLR4 expression, whereas in the colon, TLR2 and TLR4 affect IL-10 expression independently. Intestinal epithelial cells could release IL-10 in response to TLR activation, playing an intestinal tissue-dependent and critical intestinal immune role.

  6. Distinct Patterns of Dendritic Cell Cytokine Release Stimulated by Fungal β-Glucans and Toll-Like Receptor Agonists▿

    PubMed Central

    Huang, Haibin; Ostroff, Gary R.; Lee, Chrono K.; Wang, Jennifer P.; Specht, Charles A.; Levitz, Stuart M.

    2009-01-01

    β-Glucans derived from fungal cell walls have potential uses as immunomodulating agents and vaccine adjuvants. Yeast glucan particles (YGPs) are highly purified Saccharomyces cerevisiae cell walls composed of β1,6-branched β1,3-d-glucan and free of mannans. YGPs stimulated secretion of the proinflammatory cytokine tumor necrosis factor alpha (TNF-α) in wild-type murine bone marrow-derived myeloid dendritic cells (BMDCs) but did not stimulate interleukin-12p70 (IL-12p70) production. A purified soluble β1,6-branched β1,3-d-glucan, scleroglucan, also stimulated TNF-α in BMDCs. These two β-glucans failed to stimulate TNF-α in Dectin-1 (β-glucan receptor) knockout BMDCs. Costimulation of wild-type BMDCs with β-glucans and specific Toll-like receptor (TLR) ligands resulted in greatly enhanced TNF-α production but decreased IL-12p70 production compared with TLR agonists alone. The upregulation of TNF-α and downregulation of IL-12p70 required Dectin-1, but not IL-10. Gamma interferon (IFN-γ) priming did not overcome IL-12p70 reduction by β-glucans. Similar patterns of cytokine regulation were observed in human monocyte-derived dendritic cells (DCs) costimulated with YGPs and the TLR4 ligand lipopolysaccharide. Finally, costimulation of BMDCs with YGPs and either the TLR9 ligand, CpG, or the TLR2/1 ligand, Pam3CSK4, resulted in upregulated secretion of IL-1α and IL-10 and downregulated secretion of IL-1β, IL-6, and IFN-γ-inducible protein 10 but had no significant effects on IL-12p40, keratinocyte-derived chemokine, monocyte chemotactic protein 1, or macrophage inflammatory protein α, compared with the TLR ligand alone. Thus, β-glucans have distinct effects on cytokine responses following DC stimulation with different TLR agonists. These patterns of response might contribute to the skewing of immune responses during mycotic infections and have implications for the design of immunomodulators and vaccines containing β-glucans. PMID:19273561

  7. Interaction Between Helminths and Toll-Like Receptors: Possibilities and Potentials for Asthma Therapy.

    PubMed

    Zakeri, Amin; Borji, Hassan; Haghparast, Alireza

    2016-05-03

    Toll-like receptors (TLRs) are essential components of the innate immune system. They play an important role in the pathogenesis of allergic diseases, especially asthma. Since TLRs significantly orchestrate innate and adaptive immune response, their manipulation has widely been considered as a potential approach to control asthma symptoms. It is well established that helminths have immunoregulatory effects on host immune responses, especially innate immunity. They release bioactive molecules such as excretory-secretory (ES) products manipulating TLRs expression and signaling. Thus, given the promising results derived from preclinical studies, harnessing helminth-derived molecules affecting TLRs can be considered as a potential biological therapy for allergic diseases. Prospectively, the data that are available at present suggest that, in the near future, it is possible that helminth antigens will offer new therapeutic strategies and druggable targets for fighting allergic diseases. This review describes the interactions between helminths and TLRs and discusses the potential possibilities for asthma therapy. In this opinion paper, the authors aimed to review the updated literatures on the interplay between helminths, TLRs, and asthma with a view to proposing helminth-based asthma therapy.

  8. Resolution of Toll-like receptor 4-mediated acute lung injury is linked to eicosanoids and suppressor of cytokine signaling 3

    PubMed Central

    Hilberath, Jan N.; Carlo, Troy; Pfeffer, Michael A.; Croze, Roxanne H.; Hastrup, Frantz; Levy, Bruce D.

    2011-01-01

    The purpose of this study was to investigate roles for Toll-like receptor 4 (TLR4) in host responses to sterile tissue injury. Hydrochloric acid was instilled into the left mainstem bronchus of TLR4-defective (both C3H/HeJ and congenic C.C3-Tlr4Lps-d/J) and control mice to initiate mild, self-limited acute lung injury (ALI). Outcome measures included respiratory mechanics, barrier integrity, leukocyte accumulation, and levels of select soluble mediators. TLR4-defective mice were more resistant to ALI, with significantly decreased perturbations in lung elastance and resistance, resulting in faster resolution of these parameters [resolution interval (Ri); ∼6 vs. 12 h]. Vascular permeability changes and oxidative stress were also decreased in injured HeJ mice. These TLR4-defective mice paradoxically displayed increased lung neutrophils [(HeJ) 24×103 vs. (control) 13×103 cells/bronchoalveolar lavage]. Proresolving mechanisms for TLR4-defective animals included decreased eicosanoid biosynthesis, including cysteinyl leukotrienes (80% mean decrease) that mediated CysLT1 receptor-dependent vascular permeability changes; and induction of lung suppressor of cytokine signaling 3 (SOCS3) expression that decreased TLR4-driven oxidative stress. Together, these findings indicate pivotal roles for TLR4 in promoting sterile ALI and suggest downstream provocative roles for cysteinyl leukotrienes and protective roles for SOCS3 in the intensity and duration of host responses to ALI.—Hilberath, J N., Carlo, T., Pfeffer, M. A., Croze, R. H., Hastrup, F., Levy, B. D. Resolution of Toll-like receptor 4-mediated acute lung injury is linked to eicosanoids and suppressor of cytokine signaling 3. PMID:21321188

  9. HIV Gag protein conjugated to a Toll-like receptor 7/8 agonist improves the magnitude and quality of Th1 and CD8+ T cell responses in nonhuman primates

    NASA Astrophysics Data System (ADS)

    Wille-Reece, Ulrike; Flynn, Barbara J.; Loré, Karin; Koup, Richard A.; Kedl, Ross M.; Mattapallil, Joseph J.; Weiss, Walter R.; Roederer, Mario; Seder, Robert A.

    2005-10-01

    Induction and maintenance of antibody and T cell responses will be critical for developing a successful vaccine against HIV. A rational approach for generating such responses is to design vaccines or adjuvants that have the capacity to activate specific antigen-presenting cells. In this regard, dendritic cells (DCs) are the most potent antigen-presenting cells for generating primary T cell responses. Here, we report that Toll-like receptor (TLR) agonists and ligands that activate DCs in vitro influence the magnitude and quality of the cellular immune response in nonhuman primates (NHPs) when administered with HIV Gag protein. NHPs immunized with HIV Gag protein and a TLR7/8 agonist or a TLR9 ligand [CpG oligodeoxynucleotides (CpG ODN)] had significantly increased Gag-specific T helper 1 and antibody responses, compared with animals immunized with HIV Gag protein alone. Importantly, conjugating the HIV Gag protein to the TLR7/8 agonist (Gag-TLR7/8 conjugate) dramatically enhanced the magnitude and altered the quality of the T helper 1 response, compared with animals immunized with HIV Gag protein and the TLR7/8 agonist or CpG ODN. Furthermore, immunization with the Gag-TLR7/8 conjugate vaccine elicited Gag-specific CD8+ T responses. Collectively, our results show that conjugating HIV Gag protein to a TLR7/8 agonist is an effective way to elicit broad-based adaptive immunity in NHPs. This type of vaccine formulation should have utility in preventive or therapeutic vaccines in which humoral and cellular immunity is required. vaccine | dendritic cell | cross-presentation | cellular immunity

  10. Implicating Receptor Activator of NF-κB (RANK)/RANK Ligand Signalling in Microglial Responses to Toll-Like Receptor Stimuli

    PubMed Central

    Kichev, Anton; Eede, Pascale; Gressens, Pierre; Thornton, Claire; Hagberg, Henrik

    2017-01-01

    Inflammation in the perinatal brain caused by maternal or intrauterine fetal infection is now well established as an important contributor to the development of perinatal brain injury. Exposure to inflammatory products can impair perinatal brain development and act as a risk factor for neurological dysfunction, cognitive disorders, cerebral palsy, or preterm birth. Pre-exposure to inflammation significantly exacerbates brain injury caused by hypoxic/ischaemic insult. Tumour necrosis factor (TNF) is a family of cytokines largely involved in inflammation signalling. In our previous study, we identified the importance of TNF-related apoptosis-inducing ligand (TRAIL) signalling in the development of perinatal brain injury. We observed a significant increase in the expression levels of a soluble decoy receptor for TRAIL, osteoprotegerin (OPG). Besides TRAIL, OPG is able to bind the receptor activator of the NF-κB (RANK) ligand (RANKL) and inhibit its signalling. The function of the RANK/RANKL/OPG system in the brain has not come under much scrutiny. The aim of this research study was to elucidate the role of RANK, RANKL, and OPG in microglial responses to the proinflammatory stimuli lipopolysaccharide (LPS) and polyinosinic-polycytidylic acid (Poly I:C). Here, we show that RANK signalling is important for regulating the activation of the BV2 microglial cell line. We found that LPS treatment causes a significant decrease in the expression of RANK in the BV2 cell line while significantly increasing the expression of OPG, Toll-like receptor (TLR)3, and the adaptor proteins MyD88 and TRIF. We found that pretreatment of BV2 cells with RANKL for 24 h before the LPS or Poly I:C exposure decreases the expression of inflammatory markers such as inducible nitric oxide synthase and cyclooxygenase. This is accompanied by a decreased expression of the TLR adaptor proteins MyD88 and TRIF, which we observed after RANKL treatment. Similar results were obtained in our experiments with

  11. Implicating Receptor Activator of NF-κB (RANK)/RANK Ligand Signalling in Microglial Responses to Toll-Like Receptor Stimuli.

    PubMed

    Kichev, Anton; Eede, Pascale; Gressens, Pierre; Thornton, Claire; Hagberg, Henrik

    2017-01-01

    Inflammation in the perinatal brain caused by maternal or intrauterine fetal infection is now well established as an important contributor to the development of perinatal brain injury. Exposure to inflammatory products can impair perinatal brain development and act as a risk factor for neurological dysfunction, cognitive disorders, cerebral palsy, or preterm birth. Pre-exposure to inflammation significantly exacerbates brain injury caused by hypoxic/ischaemic insult. Tumour necrosis factor (TNF) is a family of cytokines largely involved in inflammation signalling. In our previous study, we identified the importance of TNF-related apoptosis-inducing ligand (TRAIL) signalling in the development of perinatal brain injury. We observed a significant increase in the expression levels of a soluble decoy receptor for TRAIL, osteoprotegerin (OPG). Besides TRAIL, OPG is able to bind the receptor activator of the NF-κB (RANK) ligand (RANKL) and inhibit its signalling. The function of the RANK/RANKL/OPG system in the brain has not come under much scrutiny. The aim of this research study was to elucidate the role of RANK, RANKL, and OPG in microglial responses to the proinflammatory stimuli lipopolysaccharide (LPS) and polyinosinic-polycytidylic acid (Poly I:C). Here, we show that RANK signalling is important for regulating the activation of the BV2 microglial cell line. We found that LPS treatment causes a significant decrease in the expression of RANK in the BV2 cell line while significantly increasing the expression of OPG, Toll-like receptor (TLR)3, and the adaptor proteins MyD88 and TRIF. We found that pretreatment of BV2 cells with RANKL for 24 h before the LPS or Poly I:C exposure decreases the expression of inflammatory markers such as inducible nitric oxide synthase and cyclooxygenase. This is accompanied by a decreased expression of the TLR adaptor proteins MyD88 and TRIF, which we observed after RANKL treatment. Similar results were obtained in our experiments with

  12. Sea anemone model has a single Toll-like receptor that can function in pathogen detection, NF-κB signal transduction, and development

    PubMed Central

    Brennan, Joseph J.; Messerschmidt, Jonathan L.; Williams, Leah M.; Matthews, Bryan J.; Reynoso, Marinaliz; Gilmore, Thomas D.

    2017-01-01

    In organisms from insects to vertebrates, Toll-like receptors (TLRs) are primary pathogen detectors that activate downstream pathways, specifically those that direct expression of innate immune effector genes. TLRs also have roles in development in many species. The sea anemone Nematostella vectensis is a useful cnidarian model to study the origins of TLR signaling because its genome encodes a single TLR and homologs of many downstream signaling components, including the NF-κB pathway. We have characterized the single N. vectensis TLR (Nv-TLR) and demonstrated that it can activate canonical NF-κB signaling in human cells. Furthermore, we show that the intracellular Toll/IL-1 receptor (TIR) domain of Nv-TLR can interact with the human TLR adapter proteins MAL and MYD88. We demonstrate that the coral pathogen Vibrio coralliilyticus causes a rapidly lethal disease in N. vectensis and that heat-inactivated V. coralliilyticus and bacterial flagellin can activate a reconstituted Nv-TLR–to–NF-κB pathway in human cells. By immunostaining of anemones, we show that Nv-TLR is expressed in a subset of cnidocytes and that many of these Nv-TLR–expressing cells also express Nv-NF-κB. Additionally, the nematosome, which is a Nematostella-specific multicellular structure, expresses Nv-TLR and many innate immune pathway homologs and can engulf V. coralliilyticus. Morpholino knockdown indicates that Nv-TLR also has an essential role during early embryonic development. Our characterization of this primitive TLR and identification of a bacterial pathogen for N. vectensis reveal ancient TLR functions and provide a model for studying the molecular basis of cnidarian disease and immunity. PMID:29109290

  13. Toll-Like Receptor-3 Is Dispensable for the Innate MicroRNA Response to West Nile Virus (WNV)

    PubMed Central

    Chugh, Pauline E.; Damania, Blossom A.; Dittmer, Dirk P.

    2014-01-01

    The innate immune response to West Nile virus (WNV) infection involves recognition through toll-like receptors (TLRs) and RIG-I-like receptors (RLRs), leading to establishment of an antiviral state. MiRNAs (miRNAs) have been shown to be reliable biomarkers of TLR activation. Here, we sought to evaluate the contribution of TLR3 and miRNAs to the host response to WNV infection. We first analyzed HEK293-NULL and HEK293-TLR3 cells for changes in the innate immune response to infection. The presence of TLR3 did not seem to affect WNV load, infectivity or phosphorylation of IRF3. Analysis of experimentally validated NFκB-responsive genes revealed a WNV-induced signature largely independent of TLR3. Since miRNAs are involved in viral pathogenesis and the innate response to infection, we sought to identify changes in miRNA expression upon infection in the presence or absence of TLR3. MiRNA profiling revealed 70 miRNAs induced following WNV infection in a TLR3-independent manner. Further analysis of predicted gene targets of WNV signature miRNAs revealed genes highly associated with pathways regulating cell death, viral pathogenesis and immune cell trafficking. PMID:25127040

  14. A Toll-Like Receptor 9 Antagonist Improves Bladder Function and White Matter Sparing in Spinal Cord Injury

    PubMed Central

    David, Brian T.; Sampath, Sujitha; Dong, Wei; Heiman, Adee; Rella, Courtney E.; Elkabes, Stella

    2014-01-01

    Abstract Spinal cord injury (SCI) affects motor, sensory, and autonomic functions. As current therapies do not adequately alleviate functional deficits, the development of new and more effective approaches is of critical importance. Our earlier investigations indicated that intrathecal administration of a toll-like receptor 9 (TLR9) antagonist, cytidine-phosphate-guanosine oligodeoxynucleotide 2088 (CpG ODN 2088), to mice sustaining a severe, mid-thoracic contusion injury diminished neuropathic pain but did not alter locomotor deficits. These changes were paralleled by a decrease in the pro-inflammatory response at the injury epicenter. Using the same SCI paradigm and treatment regimen, the current studies investigated the effects of the TLR9 antagonist on bladder function. We report that the TLR9 antagonist decreases SCI-elicited urinary retention and ameliorates bladder morphopathology without affecting kidney function. A significant improvement in white matter sparing was also observed, most likely due to alterations in the inflammatory milieu. These findings indicate that the TLR9 antagonist has beneficial effects not only in reducing sensory deficits, but also on bladder dysfunction and tissue preservation. Thus, modulation of innate immune receptor signaling in the spinal cord can impact the effects of SCI. PMID:24936867

  15. A toll-like receptor 9 antagonist improves bladder function and white matter sparing in spinal cord injury.

    PubMed

    David, Brian T; Sampath, Sujitha; Dong, Wei; Heiman, Adee; Rella, Courtney E; Elkabes, Stella; Heary, Robert F

    2014-11-01

    Spinal cord injury (SCI) affects motor, sensory, and autonomic functions. As current therapies do not adequately alleviate functional deficits, the development of new and more effective approaches is of critical importance. Our earlier investigations indicated that intrathecal administration of a toll-like receptor 9 (TLR9) antagonist, cytidine-phosphate-guanosine oligodeoxynucleotide 2088 (CpG ODN 2088), to mice sustaining a severe, mid-thoracic contusion injury diminished neuropathic pain but did not alter locomotor deficits. These changes were paralleled by a decrease in the pro-inflammatory response at the injury epicenter. Using the same SCI paradigm and treatment regimen, the current studies investigated the effects of the TLR9 antagonist on bladder function. We report that the TLR9 antagonist decreases SCI-elicited urinary retention and ameliorates bladder morphopathology without affecting kidney function. A significant improvement in white matter sparing was also observed, most likely due to alterations in the inflammatory milieu. These findings indicate that the TLR9 antagonist has beneficial effects not only in reducing sensory deficits, but also on bladder dysfunction and tissue preservation. Thus, modulation of innate immune receptor signaling in the spinal cord can impact the effects of SCI.

  16. Disifin (sodium tosylchloramide) and Toll-like receptors (TLRs): evolving importance in health and diseases.

    PubMed

    Ofodile, Okom Nkili F C

    2007-12-01

    Disifin has emerged as a unique and very effective agent used in disinfection of wounds, disinfection of surfaces, materials and water, and other substances contaminated with almost every type of pathogenic microorganism ranging from viruses, bacteria, fungi and yeast, and, very possibly, protozoan parasites, as well. The major active component of Disifin is tosylchloramide sodium (chloramine T). However, the mechanism by which Disifin suppresses the activities of pathogenic microbial agents remains enigmatic. The molecular mechanisms, and the receptors and the signal transducing pathways responsible for the biological effects of Disifin are largely unknown. Despite considerable advances, enormous investigative efforts and large resources invested in the research on infectious diseases, microbial infection still remains a public health problem in many parts of the world. The exact nature of the pathogenic agents responsible for many infectious diseases, and the nature of the receptors mediating the associated inflammatory events are incompletely understood. Recent advances in understanding the molecular basis for mammalian host immune responses to microbial invasion suggest that the first line of defense against microbes is the recognition of pathogen-associated molecular patterns (PAMPs) by a family of transmembrane pattern-recognizing and signal transducing receptor proteins called Toll-like receptors (TLRs). The TLR family plays an instructive role in innate immune responses against microbial pathogens, as well as the subsequent induction of adaptive immune responses. TLRs mediate recognition and inflammatory responses to a wide range of microbial products and are crucial for effective host defense by eradication of the invading pathogens. Now, recent updates demonstrated the ability of Disifin-derived products, Disifin-Animal and Disifin-Pressant to effectively suppress the progression and activities of Chikungunya fever and that of avian influenza A virus [A

  17. Controversial roles played by toll like receptor 4 in urinary bladder cancer; A systematic review.

    PubMed

    Afsharimoghaddam, Amin; Soleimani, Mohammad; Lashay, Alireza; Dehghani, Mahdi; Sepehri, Zahra

    2016-08-01

    Urinary bladder cancer (UBC) is a prevalent human cancer. The main mechanisms which lead to eradication or progression the disease has yet to be clarified. Toll like receptor (TLR) 4 is a membrane receptor which is expressed either on immune cells or tumor cells. This review article was aimed to clear the main mechanisms played by TLR4 and its related intracellular pathways on outcome of UBC. PubMed, Scopus and Google scholar databases have been used for searching related research articles which have evaluated the roles played by TLR4 and its related intracellular pathways on outcome of UBC. Collected information from the related articles revealed that TLR4 either participates in induction of immune responses against UBC or development of the malignancy. There are limited investigations regarding the genetic variations of TLR4 in UBC. According to the results it seems that TLR4/ligands interaction outcome is dependent on several factors including TLR4 ligand doses, interaction of TLR4 with its ligands on immune cells or tumor cells, and other TLRs/ligand interaction simultaneously. Copyright © 2016 Elsevier Inc. All rights reserved.

  18. Activation of Toll-like receptor 3 increases mouse aortic vascular smooth muscle cell contractility through ERK1/2 pathway.

    PubMed

    Hardigan, Trevor; Spitler, Kathryn; Matsumoto, Takayuki; Carrillo-Sepulveda, Maria Alicia

    2015-11-01

    Activation of Toll-like receptor 3 (TLR3), a pattern recognition receptor of the innate immune system, is associated with vascular complications. However, whether activation of TLR3 alters vascular contractility is unknown. We, therefore, hypothesized that TLR3 activation augments vascular contractility and activates vascular smooth muscle cell (VSMC) contractile apparatus proteins. Male mice were treated with polyinosinic-polycytidylic acid (Poly I:C group, 14 days), a TLR3 agonist; control mice received saline (vehicle, 14 days). At the end of protocol, blood pressure was measured by tail cuff method. Aortas were isolated and assessed for contractility experiments using a wire myograph. Aortic protein content was used to determine phosphorylated/total interferon regulatory factor 3 (IRF3), a downstream target of TLR3 signaling, and ERK1/2 using Western blot. We investigated the TLR3/IRF3/ERK1/2 signaling pathway and contractile-related proteins such as phosphorylated/total myosin light chain (MLC) and caldesmon (CaD) in aortic VSMC primary cultures. Poly I:C-treated mice exhibited (vs. vehicle-treated mice) (1) elevated systolic blood pressure. Moreover, Poly I:C treatment (2) enhanced aortic phenylephrine-induced maximum contraction, which was suppressed by PD98059 (ERK1/2 inhibitor), and (3) increased aortic levels of phosphorylated IRF3 and ERK1/2. Stimulation of mouse aortic VSMCs with Poly I:C resulted in increased phosphorylation of IRF3, ERK1/2, MLC, and CaD. Inhibition of ERK1/2 abolished Poly I:C-mediated phosphorylation of MLC and CaD. Our data provide functional evidence for the role of TLR3 in vascular contractile events, suggesting TLR3 as a potential new therapeutic target in vascular dysfunction and regulation of blood pressure.

  19. Toll-like Receptor 2: A Novel Therapeutic Target for Ischemic White Matter Injury and Oligodendrocyte Death

    PubMed Central

    Choi, Jun Young

    2017-01-01

    Despite paramount clinical significance of white matter stroke, there is a paucity of researches on the pathomechanism of ischemic white matter damage and accompanying oligodendrocyte (OL) death. Therefore, a large gap exists between clinical needs and laboratory researches in this disease entity. Recent works have started to elucidate cellular and molecular basis of white matter injury under ischemic stress. In this paper, we briefly introduce white matter stroke from a clinical point of view and review pathophysiology of ischemic white matter injury characterized by OL death and demyelination. We present a series of evidence that Toll-like receptor 2 (TLR2), one of the membranous pattern recognition receptors, plays a cell-autonomous protective role in ischemic OL death and ensuing demyelination. Moreover, we also discuss our recent findings that its endogenous ligand, high-mobility group box 1 (HMGB1), is released from dying OLs and exerts autocrine trophic effects on OLs and myelin sheath under ischemic condition. We propose that modulation of TLR2 and its endogenous ligand HMGB1 can be a novel therapeutic target for ischemic white matter disease. PMID:28912641

  20. Increased Expression of Toll-Like Receptors by Monocytes and Natural Killer Cells in ANCA-Associated Vasculitis

    PubMed Central

    Tadema, Henko; Abdulahad, Wayel H.; Stegeman, Coen A.; Kallenberg, Cees G. M.; Heeringa, Peter

    2011-01-01

    Introduction Toll-like receptors (TLRs) are a family of receptors that sense pathogen associated patterns such as bacterial cell wall proteins. Bacterial infections are associated with anti-neutrophil cytoplasmic antibodies (ANCA)-associated vasculitis (AAV). Here, we assessed the expression of TLRs 2, 4, and 9 by peripheral blood leukocytes from patients with AAV, and investigated TLR mediated responses ex vivo. Methods Expression of TLRs was determined in 38 AAV patients (32 remission, 6 active disease), and 20 healthy controls (HC). Membrane expression of TLRs 2, 4, and 9, and intracellular expression of TLR9 by B lymphocytes, T lymphocytes, NK cells, monocytes and granulocytes was assessed using 9-color flowcytometry. Whole blood from 13 patients and 7 HC was stimulated ex vivo with TLR 2, 4 and 9 ligands and production of cytokines was analyzed. Results In patients, we observed increased proportions of TLR expressing NK cells. Furthermore, patient monocytes expressed higher levels of TLR2 compared to HC, and in a subset of patients an increased proportion of TLR4+ monocytes was observed. Monocytes from nasal carriers of Staphylococcus aureus expressed increased levels of intracellular TLR9. Membrane expression of TLRs by B lymphocytes, T lymphocytes, and granulocytes was comparable between AAV patients and HC. Patients with active disease did not show differential TLR expression compared to patients in remission. Ex vivo responses to TLR ligands did not differ significantly between patients and HC. Conclusions In AAV, monocytes and NK cells display increased TLR expression. Increased TLR expression by these leukocytes, probably resulting from increased activation, could play a role in disease (re)activation. PMID:21915309

  1. Endocytosis of particulate matter induces cytokine production by neutrophil via Toll-like receptor 4.

    PubMed

    Miyake, Tadahiro; Wang, Duo; Matsuoka, Hidetada; Morita, Kentaro; Yasuda, Hiroshi; Yatera, Kazuhiro; Kanazawa, Tamotsu; Yoshida, Yasuhiro

    2018-04-01

    Particulate matter (PM) with a median diameter <2.5 μm, is associated with respiratory and cardiovascular diseases. We previously reported the biological effects of PM in vivo, and although neutrophils play an important role in initiating inflammation, few reports have focused on the relationship between PM inhalation and immune responses. Here, we investigated the effect of PM particle size on neutrophils, including their endocytosis activity and reactive oxygen species (ROS) production. Flow cytometry analysis indicated that 1 μm particles are readily endocytosed by neutrophils and that endocytosis is reduced at 4 °C. Inhibitors of the pleckstrin homology domain of dynamin repressed this process; however, GTPase and clathrin inhibitors did not affect endocytosis. Endocytosis by neutrophils in Toll-like receptor 4 (TLR4)- and MyD88-knockout mice was reduced compared with that in wild-type mice, indicating that TLR4 and MyD88 are important for the process. Neutrophil-mediated endocytosis caused oxidative stress, and N-acetylcysteine enhanced endocytosis. Expression levels of the oxidative stress markers, heme oxygenase-1 and p62 protein, were increased in an endocytosis-dependent manner. Phagocytosed neutrophils produced IL-6 and TNFα, whose production was decreased by dynamin inhibitors. We observed that infiltrated CD11b-positive cells in bronchoalveolar lavage fluid endocytose PMs. Overall, these results indicate that endocytosis and ROS production via TLR4 are important for the initiation of immune responses by neutrophils. Copyright © 2018 Elsevier B.V. All rights reserved.

  2. Toll-like receptor 4 regulates lipopolysaccharide-induced inflammation and lactation insufficiency in a mouse model of mastitis.

    PubMed

    Glynn, Danielle J; Hutchinson, Mark R; Ingman, Wendy V

    2014-05-01

    Lactation mastitis is a debilitating inflammatory breast disease in postpartum women. Disease severity is associated with markers of inflammation rather than bacterial load, suggesting that immune-signaling pathways activated in the host are important in the disease pathology. The role of the innate pattern recognition receptor toll-like receptor 4 (TLR4) in progression and resolution of mastitislike disease was investigated in a mouse model. Lipopolysaccharide in Matrigel (10 μg/10 μl) was administered into the teat canal of lactating Tlr4 null mutant and wild-type mice to induce a localized area of inflammation. Mastitis induction resulted in a marked influx of RB6-positive neutrophils and F4/80-positive macrophages, which was higher in Tlr4(-/-) mice compared to wild-type mice. Tlr4 null mutation resulted in an altered immune-signaling fingerprint following induction of mastitis, with attenuated serum cytokines, including CXCL1, CCL2, interleukin 1 beta, and tumor necrosis factor alpha compared to wild-type mice. In both genotypes, the localized area of inflammation had resolved after 7 days, and milk protein was evident. However, the mammary glands of wild-type mice exhibited reduced capacity for milk production, with decreased percent area populated with glandular epithelium and decreased abundance of nuclear phosphorylated signal transducer and activator of transcription 5 compared to Tlr4 null mice. This study demonstrates that inflammatory pathways activated in the host are critically important in mastitis disease progression and suggests that lactation insufficiency associated with mastitis may be a consequence of TLR4-mediated inflammation, rather than the bacterial infection itself.

  3. Evidence that opioids may have toll like receptor 4 and MD-2 effects

    PubMed Central

    Hutchinson, Mark R.; Zhang, Yingning; Shridhar, Mitesh; Evans, John H.; Buchanan, Madison M.; Zhao, Tina X.; Slivka, Peter F.; Coats, Benjamen D.; Rezvani, Niloofar; Wieseler, Julie; Hughes, Travis S.; Landgraf, Kyle E.; Chan, Stefanie; Fong, Stephanie; Phipps, Simon; Falke, Joseph J.; Leinwand, Leslie A.; Maier, Steven F.; Yin, Hang; Rice, Kenner C.; Watkins, Linda R.

    2009-01-01

    Opioid-induced proinflammatory glial activation modulates wide-ranging aspects of opioid pharmacology including: opposition of acute and chronic opioid analgesia, opioid analgesic tolerance, opioid-induced hyperalgesia, development of opioid dependence, opioid reward, and opioid respiratory depression. However, the mechanism(s) contributing to opioid-induced proinflammatory actions remains unresolved. The potential involvement of toll like receptor 4 (TLR4) was examined using in vitro, in vivo, and in silico techniques. Morphine non-stereoselectively induced TLR4 signaling in vitro, blocked by a classical TLR4 antagonist and non-stereoselectively by naloxone. Pharmacological blockade of TLR4 signaling in vivo potentiated acute intrathecal morphine analgesia, attenuated development of analgesic tolerance, hyperalgesia, and opioid withdrawal behaviors. TLR4 opposition to opioid actions was supported by morphine treatment of TLR4 knockout mice, which revealed a significant threefold leftward shift in the analgesia dose response function, versus wildtype mice. A range of structurally diverse clinically employed opioid analgesics was found to be capable of activating TLR4 signaling in vitro. Selectivity in the response was identified since morphine-3-glucuronide, a morphine metabolite with no opioid receptor activity, displayed significant TLR4 activity, whilst the opioid receptor active metabolite, morphine-6-glucuronide, was devoid of such properties. In silico docking simulations revealed ligands bound preferentially to the LPS binding pocket of MD-2 rather than TLR4. An in silico to in vitro prediction model was built and tested with substantial accuracy. These data provide evidence that select opioids may non-stereoselectively influence TLR4 signaling and have behavioral consequences resulting, in part, via TLR4 signaling. PMID:19679181

  4. Disseminated cysticercosis: clinical spectrum, Toll-like receptor-4 gene polymorphisms and role of albendazole: A prospective follow-up of 60 cases with a review of 56 published cases.

    PubMed

    Qavi, Abdul; Garg, Ravindra Kumar; Malhotra, Hardeep Singh; Jain, Amita; Kumar, Neeraj; Malhotra, Kiran Preet; Srivastava, Pradeep Kumar; Verma, Rajesh; Sharma, Praveen Kumar

    2016-09-01

    In this study, we describe clinical and imaging spectrum, and the natural course of patients with disseminated cysticercosis. How albendazole affects the course of disease has also been evaluated. We assessed the Toll-like receptor-4 gene polymorphisms, to know the reason for the apparently higher prevalence of disseminated cysticercosis in India.Sixty consecutive patients with disseminated cysticercosis were enrolled. Sixty age-and-sex-matched healthy controls were also enrolled for the purpose of genetic study. Twenty patients, who gave consent, were treated with albendazole along with corticosteroids. Forty patients did not give consent for antiparasitic therapy. Assessment for Toll-like receptor-4 gene polymorphisms (Asp299Gly and Thr399Ile genes) was done. Patients were followed for 6 months. We also performed a literature search of cases published in English language using PubMed electronic database and analyzed 56 cases thus available.There was an increased risk (6.63 fold and 4.61 fold) of disseminated cysticercosis in the presence of Asp299Gly and Thr399Ile polymorphisms in Toll-like receptor-4, respectively. The allelic frequency of Gly (11% vs. 3%, P = 0.024, odds ratio [OR] = 3.52) and Ile alleles (11% vs. 2%, P = 0.009, OR = 4.738) in disseminated cysticercosis was high. Albendazole resulted in complete disappearance of all cerebral lesions in 35% (7/20) patients and reduction in lesion load in remaining 65% (13/20) patients. No significant change in number of cysticercal lesion was noted in patients who did not receive albendazole. No major adverse reaction following antiparasitic treatment was noted. Three deaths were recorded in patients who did not receive antiparasitic treatment.Of the 56 cases reported in PubMed, 33 patients received antiparasitic treatment with follow-up data available for 31 patients. Most (24) of these patients received albendazole. A significant clinical and/or imaging improvements, on follow up, were observed in 27 patients

  5. Cigarette smoke increases Toll-like receptor 4 and modifies lipopolysaccharide-mediated responses in airway epithelial cells

    PubMed Central

    Pace, Elisabetta; Ferraro, Maria; Siena, Liboria; Melis, Mario; Montalbano, Angela M; Johnson, Malcolm; Bonsignore, Maria R; Bonsignore, Giovanni; Gjomarkaj, Mark

    2008-01-01

    Airway epithelium is emerging as a regulator of innate immune responses to a variety of insults including cigarette smoke. The main goal of this study was to explore the effects of cigarette smoke extracts (CSE) on Toll-like receptor (TLR) expression and activation in a human bronchial epithelial cell line (16-HBE). The CSE increased the expression of TLR4 and the lipopolysaccharide (LPS) binding, the nuclear factor-κB (NF-κB) activation, the release of interleukin-8 (IL-8) and the chemotactic activity toward neutrophils. It did not induce TLR2 expression or extracellular signal-regulated signal kinase 1/2 (ERK1/2) activation. The LPS increased the expression of TLR4 and induced both NF-κB and ERK1/2 activation. The combined exposure of 16-HBE to CSE and LPS was associated with ERK activation rather than NF-κB activation and with a further increase of IL-8 release and of chemotactic activity toward neutrophils. Furthermore, CSE decreased the constitutive interferon-inducible protein-10 (IP-10) release and counteracted the effect of LPS in inducing both the IP-10 release and the chemotactic activity toward lymphocytes. In conclusion, cigarette smoke, by altering the expression and the activation of TLR4 via the preferential release of IL-8, may contribute to the accumulation of neutrophils within the airways of smokers. PMID:18217953

  6. Toll like receptor 4 contributes to blood pressure regulation and vascular contraction in spontaneously hypertensive rat

    PubMed Central

    Bomfim, Gisele F.; Dos Santos, Rosangela A.; Oliveira, Maria Aparecida; Giachini, Fernanda R.; Akamine, Eliana H.; Tostes, Rita C.; Fortes, Zuleica B.; Webb, R. Clinton; Carvalho, Maria Helena C.

    2014-01-01

    Activation of Toll-like receptors (TLR) induces gene expression of proteins involved in the immune system response. TLR4 has been implicated in the development and progression of cardiovascular diseases. Innate and adaptive immunity contribute to hypertension-associated end-organ damage, although the mechanism by which this occurs remains unclear. In the present study we hypothesize that inhibition of TLR4 decreases blood pressure and improves vascular contractility in resistance arteries from spontaneously hypertensive rats (SHR). TLR4 protein expression in mesenteric resistance arteries was higher in 15 weeks-old SHR than in same age Wistar controls or in 5 weeks-old SHR. In order to decrease activation of TLR4, 15 weeks-old SHR and Wistar rats were treated with anti-TLR4 antibody or non-specific IgG control antibody for 15 days (1µg per day, i.p.). Treatment with anti-TLR4 decreased mean arterial pressure as well as TLR4 protein expression in mesenteric resistance arteries and interleukin-6 (IL-6) serum levels from SHR when compared to SHR treated with IgG. No changes in these parameters were found in Wistar treated rats. Mesenteric resistance arteries from anti-TLR4-treated SHR exhibited decreased maximal contractile response to noradrenaline compared to IgG-treated-SHR. Inhibition of cyclooxygenase-1 (Cox) and Cox-2, enzymes related to inflammatory pathways, decreased noradrenaline responses only in mesenteric resistance arteries of SHR treated with IgG. Cox-2 expression and thromboxane A2 release were decreased in SHR treated with anti-TLR4 compared with IgG-treated-SHR. Our results suggest that TLR4 activation contributes to increased blood pressure, low grade inflammation and plays a role in the augmented vascular contractility displayed by SHR. PMID:22233532

  7. Toll-like receptor 9 deficiency impacts sensory and motor behaviors.

    PubMed

    Khariv, Veronika; Pang, Kevin; Servatius, Richard J; David, Brian T; Goodus, Matthew T; Beck, Kevin D; Heary, Robert F; Elkabes, Stella

    2013-08-01

    Toll-like receptors (TLRs) mediate the induction of the innate immune system in response to pathogens, injury and disease. However, they also play non-immune roles and are expressed in the central nervous system (CNS) during prenatal and postnatal stages including adulthood. Little is known about their roles in the CNS in the absence of pathology. Several members of the TLR family have been implicated in the development of neural and cognitive function although the contribution of TLR9 to these processes has not been well defined. The current studies were undertaken to determine whether developmental TLR9 deficiency affects motor, sensory or cognitive functions. We report that TLR9 deficient (TLR9(-/-)) mice show a hyper-responsive sensory and motor phenotype compared to wild type (TLR9(+/+)) controls. This is indicated by hypersensitivity to thermal stimuli in the hot plate paw withdrawal test, enhanced motor-responsivity under anxious conditions in the open field test and greater sensorimotor reactivity in the acoustic startle response. Prepulse inhibition (PPI) of the acoustic startle response was also enhanced, which indicates abnormal sensorimotor gating. In addition, subtle, but significant, gait abnormalities were noted in the TLR9(-/-) mice on the horizontal balance beam test with higher foot slip numbers than TLR9(+/+) controls. In contrast, spatial learning and memory, assessed by the Morris water maze, was similar in the TLR9(-/-) and TLR9(+/+) mice. These findings support the notion that TLR9 is important for the appropriate development of sensory and motor behaviors. Copyright © 2013 Elsevier Inc. All rights reserved.

  8. The acylation state of mycobacterial lipomannans modulates innate immunity response through toll-like receptor 2.

    PubMed

    Gilleron, Martine; Nigou, Jérôme; Nicolle, Delphine; Quesniaux, Valérie; Puzo, Germain

    2006-01-01

    Detection of Mycobacterium tuberculosis antigens by professional phagocytes via toll-like receptors (TLR) contributes to controlling chronic M. tuberculosis infection. Lipomannans (LM), which are major lipoglycans of the mycobacterial envelope, were recently described as agonists of TLR2 with potent activity on proinflammatory cytokine regulation. LM correspond to a heterogeneous population of acyl- and glyco-forms. We report here the purification and the complete structural characterization of four LM acyl-forms from Mycobacterium bovis BCG using MALDI MS and 2D (1)H-(31)P NMR analyses. All this biochemical work provided the tools to investigate the implication of LM acylation degree on its proinflammatory activity. The latter was ascribed to the triacylated LM form, essentially an agonist of TLR2, using TLR2/TLR1 heterodimers for signaling. Altogether, these findings shed more light on the molecular basis of LM recognition by TLR.

  9. Increased expression of Toll-like receptors (TLRs) 7 and 9 and other cytokines in systemic lupus erythematosus (SLE) patients: ethnic differences and potential new targets for therapeutic drugs.

    PubMed

    Lyn-Cook, Beverly D; Xie, Chenghui; Oates, Jarren; Treadwell, Edward; Word, Beverly; Hammons, George; Wiley, Kenneth

    2014-09-01

    Increased expression of pro-inflammatory cytokines such as interferon, tumor necrosis factors (TNFs) and specific interleukins (ILs) has been found in a number of autoimmune diseases, including systemic lupus erythematous (SLE). These cytokines are induced by toll-like receptors (TLRs). Toll-like receptors are activated in response to accumulation of apoptotic bodies. These receptors play critical roles in innate immune systems. Increased levels of interferon-alpha (INF-α) have also been found in many SLE patients and often correlate with disease severity. The objectives of this study were to examine the expression of selected TLRs and cytokines that have been identified in animal models and some limited human studies in a group of African Americans (AA) and European Americans (EA) women with lupus in comparison to age-matched non-lupus women. Blood samples were consecutively obtained by informed consent from 286 patients, 153 lupus and 136 non-lupus, seen in the rheumatology clinics at East Carolina University. Cytokines were analyzed from blood serum using enzyme linked immunoassay (ELISA) for IL-6 and INF-α. Total RNA was isolated, using a Paxgene kit, from peripheral blood mononuclear cells of African American and European American women blood samples. Quantitative real-time PCR using the CFX real-time system was conducted on all samples to determine TLRs 7 and 9, as well as INF-α expression. Toll-like receptor 7 (p<0.01) and 9 (p=0.001) expression levels were significantly increased in lupus patients compared to age-matched controls. African American women with lupus had a 2-fold increase in TLR-9 expression level when compared to their healthy controls or European American lupus patients. However, there was no ethnic difference in expression of TLR-7 in lupus patients. INF-α expression was significantly higher in lupus patients (p<0.0001) and also showed ethnic difference in expression. Serum levels revealed significant increases in expression of IL-6

  10. Reduced cerebral ischemia-reperfusion injury in Toll-like receptor 4 deficient mice

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Cao Canxiang; Yang Qingwu; Lv Fenglin

    Inflammatory reaction plays an important role in cerebral ischemia-reperfusion injury, however, its mechanism is still unclear. Our study aims to explore the function of Toll-like receptor 4 (TLR4) in the process of cerebral ischemia-reperfusion. We made middle cerebral artery ischemia-reperfusion model in mice with line embolism method. Compared with C3H/OuJ mice, scores of cerebral water content, cerebral infarct size and neurologic impairment in C3H/Hej mice were obviously lower after 6 h ischemia and 24 h reperfusion. Light microscopic and electron microscopic results showed that cerebral ischemia-reperfusion injury in C3H/Hej mice was less serious than that in C3H/OuJ mice. TNF-{alpha} andmore » IL-6 contents in C3H/HeJ mice were obviously lower than that in C3H/OuJ mice with ELISA. The results showed that TLR4 participates in the process of cerebral ischemia-reperfusion injury probably through decrease of inflammatory cytokines. TLR4 may become a new target for prevention of cerebral ischemia-reperfusion injury. Our study suggests that TLR4 is one of the mechanisms of cerebral ischemia-reperfusion injury besides its important role in innate immunity.« less

  11. Neu1 sialidase and matrix metalloproteinase-9 cross-talk regulates nucleic acid-induced endosomal TOLL-like receptor-7 and -9 activation, cellular signaling and pro-inflammatory responses.

    PubMed

    Abdulkhalek, Samar; Szewczuk, Myron R

    2013-11-01

    The precise mechanism(s) by which intracellular TOLL-like receptors (TLRs) become activated by their ligands remains unclear. Here, we report a molecular organizational G-protein coupled receptor (GPCR) signaling platform to potentiate a novel mammalian neuraminidase-1 (Neu1) and matrix metalloproteinase-9 (MMP-9) cross-talk in alliance with neuromedin B GPCR, all of which form a tripartite complex with TLR-7 and -9. siRNA silencing Neu1, MMP-9 and neuromedin-B GPCR in RAW-blue macrophage cells significantly reduced TLR7 imiquimod- and TLR9 ODN1826-induced NF-κB (NF-κB-pSer(536)) activity. Tamiflu, specific MMP-9 inhibitor, neuromedin B receptor specific antagonist BIM23127, and the selective inhibitor of whole heterotrimeric G-protein complex BIM-46174 significantly block nucleic acid-induced TLR-7 and -9 MyD88 recruitment, NF-κB activation and proinflammatory TNFα and MCP-1 cytokine responses. For the first time, Neu1 clearly plays a central role in mediating nucleic acid-induced intracellular TLR activation, and the interactions involving NMBR-MMP9-Neu1 cross-talk constitute a novel intracellular TLR signaling platform that is essential for NF-κB activation and pro-inflammatory responses. © 2013. Published by Elsevier Inc. All rights reserved.

  12. Stimulants of Toll-like receptor (TLR)-2 and TLR-4 are abundant in certain minimally-processed vegetables.

    PubMed

    Erridge, Clett

    2011-06-01

    Stimulants of the innate immune receptors Toll-like receptor (TLR)-2 and TLR4 have been shown to promote insulin resistance and atherosclerosis in animal models of these diseases. As minimally processed vegetables (MPV) can contain a relatively large bacterial load compared to other foodstuffs, we aimed to quantify the abundance of stimulants of TLR2 and TLR4 in MPV using a transfection-based bioassay calibrated with Escherichia coli LPS and the synthetic lipopeptide Pam(3)CSK(4). Of 5 classes of MPV and 3 classes of related vegetable products considered to be likely to contain a high microbial load, diced onion and bean sprouts contained the highest levels of stimulants of TLR2 (up to 18.5 μg Pam(3)CSK(4)-equivalents per g) and TLR4 (up to 11.4 μg LPS-equivalents per g). By contrast, the majority of fresh whole vegetables examined reproducibly contained minimal or undetectable levels of TLR2- or TLR4-stimulants. The accumulation of TLR-stimulants in MPVs correlated well with growth of enterobacterial spoilage organisms. In conclusion, the modern trend towards eating minimally processed vegetables rather than whole foods is likely to be associated with increased oral exposure to stimulants of TLR2 and TLR4. Copyright © 2011 Elsevier Ltd. All rights reserved.

  13. Contribution of Toll-like receptor/myeloid differentiation factor 88 signaling to murine liver regeneration.

    PubMed

    Seki, Ekihiro; Tsutsui, Hiroko; Iimuro, Yuji; Naka, Tetsuji; Son, Gakuhei; Akira, Shizuo; Kishimoto, Tadamitsu; Nakanishi, Kenji; Fujimoto, Jiro

    2005-03-01

    Toll-like receptors (TLRs) act as innate immune signal sensors and play central roles in host defense. Myeloid differentiation factor (MyD) 88 is a common adaptor molecule required for signaling mediated by TLRs. When the receptors are activated, cells bearing TLRs produce various proinflammatory cytokines in a MyD88-dependent manner. Liver regeneration following partial hepatectomy (PH) requires innate immune responses, particularly interleukin-6 (IL-6) and tumor necrosis factor alpha (TNF-alpha) production by Kupffer cells, although the recognition and activation processes are still unknown. We investigated whether TLR/MyD88 signaling is critical for induction of innate immune responses after PH. In Myd88(-/-) mice after PH, induction of expression of immediate early genes involved in hepatocyte replication and phosphorylation of STAT3 in the liver, and production of TNF-alpha/IL-6 by and activation of NF-kappaB in the Kupffer cells were grossly subnormal and were associated with impaired liver regeneration. However, TLR2, 4 and 9, which recognize gram-negative and -positive bacterial products, are not essential for NF-kappaB activation and IL-6 production after PH, which excludes a possible contribution of TLR2/TLR4 or TLR9 to MyD88-mediated pathways. In conclusion, the TLR/MyD88 pathway is essential for incidental liver restoration, particularly its early phase.

  14. Modulation of Immunoregulatory Properties of Mesenchymal Stromal Cells by Toll-Like Receptors: Potential Applications on GVHD

    PubMed Central

    2016-01-01

    In the last decade, the immunomodulatory properties of mesenchymal stromal cells (MSCs) have attracted a lot of attention, due to their potential applicability in the treatment of graft-versus-host disease (GVHD), a condition frequently associated with opportunistic infections. The present review addresses how Pathogen-Associated Molecular Patterns (PAMPS) modulate the immunosuppressive phenotype of human MSCs by signaling through Toll-like receptors (TLRs). Overall, we observed that regardless of the source tissue, human MSCs express TLR2, TLR3, TLR4, and TLR9. Stimulation of distinct TLRs on MSCs elicits distinct inflammatory signaling pathways, differentially influencing the expression of inflammatory factors and the ability of MSCs to suppress the proliferation of immune system cells. The capacity to enhance the immunosuppressive phenotype of MSCs through TLRs stimulation might be properly elucidated in order to improve the MSC-based immunotherapy against GVHD. PMID:27738438

  15. Toll-like receptor 2 gene polymorphisms in Chinese Holstein cattle and their associations with bovine tuberculosis.

    PubMed

    Zhao, Zhanqin; Xue, Yun; Hu, Zhigang; Zhou, Feng; Ma, Beibei; Long, Ta; Xue, Qiao; Liu, Huisheng

    2017-04-01

    This study evaluated whether there was an association between polymorphisms within the Toll-like receptor 2 gene (TLR2) of Chinese Holstein cattle and susceptibility to bovine tuberculosis (BTB). In a case-control study including 210 BTB cases and 237 control cattle, we found only two common single-nucleotide polymorphisms (SNPs) within the entire coding region of the TLR2 gene, A631G (rs95214857) and T1707C (rs1388116488). Additionally, the allele and genotype distributions of A631G and T1707C were not different between case and control groups, indicated that these SNPs were not associated with susceptibility to BTB. These results suggested that polymorphisms in the TLR2 gene might not play a significant role in the BTB risk in Chinese Holstein cattle. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. Differential effects of two probiotics on the risks of eczema and atopy associated with single nucleotide polymorphisms to Toll-like receptors.

    PubMed

    Marlow, Gareth; Han, Dug Yeo; Wickens, Kristin; Stanley, Thorsten; Crane, Julian; Mitchell, Edwin A; Dekker, James; Barthow, Christine; Fitzharris, Penny; Ferguson, Lynnette R; Morgan, Angharad R

    2015-05-01

    There is strong evidence to support a genetic predisposition to eczema and more recently studies have suggested that probiotics might be used to prevent eczema by modifying the expression of putative allergy-associated genes. The aim of this present study was to investigate whether two probiotics, Lactobacillus rhamnosus HN001 (HN001) and Bifidobacterium animalis subsp. lactis HN019 (HN019), can modify the known genetic predisposition to eczema conferred by genetic variation in the Toll-like receptor (TLR) genes in a high-risk infant population. We selected 54 SNPs in the Toll-like receptor genes. These SNPs were analysed in 331 children of sole European ancestry as part of a double-blind, randomized, placebo-controlled trial examining the effects of HN001 and HN019 supplementation on eczema development and atopic sensitization. The data showed that 26 TLR SNPs interacted with HN001 resulting in a significantly reduced risk of eczema, 18 for eczema severity as defined by SCORAD ≥ 10 and 20 for atopic sensitization compared to placebo. There were only two SNPs that interacted with HN019 resulting in a reduced risk of eczema, eczema severity or atopy. This is the first study to show that the negative impact of specific TLR genotypes may be positively affected by probiotic supplementation. HN001 exhibits a much stronger effect than HN019 in this respect. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  17. Toll like receptors gene expression of human keratinocytes cultured of severe burn injury.

    PubMed

    Cornick, Sarita Mac; Noronha, Silvana Aparecida Alves Corrêa de; Noronha, Samuel Marcos Ribeiro de; Cezillo, Marcus V B; Ferreira, Lydia Masako; Gragnani, Alfredo

    2014-01-01

    To evaluate the expression profile of genes related to Toll Like Receptors (TLR) pathways of human Primary Epidermal keratinocytes of patients with severe burns. After obtaining viable fragments of skin with and without burning, culture hKEP was initiated by the enzymatic method using Dispase (Sigma-Aldrich). These cells were treated with Trizol(r) (Life Technologies) for extraction of total RNA. This was quantified and analyzed for purity for obtaining cDNA for the analysis of gene expression using specific TLR pathways PCR Arrays plates (SA Biosciences). After the analysis of gene expression we found that 21% of these genes were differentially expressed, of which 100% were repressed or hyporegulated. Among these, the following genes (fold decrease): HSPA1A (-58), HRAS (-36), MAP2K3 (-23), TOLLIP (-23), RELA (-18), FOS (-16), and TLR1 (-6.0). This study contributes to the understanding of the molecular mechanisms related to TLR pathways and underlying wound infection caused by the burn. Furthermore, it may provide new strategies to restore normal expression of these genes and thereby change the healing process and improve clinical outcome.

  18. The protein kinase Pelle mediates feedback regulation in the Drosophila Toll signaling pathway.

    PubMed

    Towb, P; Bergmann, A; Wasserman, S A

    2001-12-01

    Dorsoventral polarity in the Drosophila embryo is established through a signal transduction cascade triggered in ventral and ventrolateral regions. Activation of a transmembrane receptor, Toll, leads to localized recruitment of the adaptor protein Tube and protein kinase Pelle. Signaling through these components directs degradation of the IkappaB-like inhibitor Cactus and nuclear translocation of the Rel protein Dorsal. Here we show through confocal immunofluorescence microscopy that Pelle functions to downregulate the signal-dependent relocalization of Tube. Inactivation of the Pelle kinase domain, or elimination of the Tube-Pelle interaction, dramatically increases Tube recruitment to the ventral plasma membrane in regions of active signaling. We also characterize a large collection of pelle alleles, identifying the molecular lesions in these alleles and their effects on Pelle autophosphorylation, Tube phosphorylation and Tube relocalization. Our results point to a mechanism operating to modulate the domain or duration of signaling downstream from Tube and Pelle.

  19. Selective Toll-Like Receptor 4 Antagonists Prevent Acute Blood-Brain Barrier Disruption After Subarachnoid Hemorrhage in Mice.

    PubMed

    Okada, Takeshi; Kawakita, Fumihiro; Nishikawa, Hirofumi; Nakano, Fumi; Liu, Lei; Suzuki, Hidenori

    2018-05-31

    There are no direct evidences showing the linkage between Toll-like receptor 4 (TLR4) and blood-brain barrier (BBB) disruption after subarachnoid hemorrhage (SAH). The purpose of this study was to examine if selective blockage of TLR4 prevents BBB disruption after SAH in mice and if the TLR4 signaling involves mitogen-activated protein kinases (MAPKs). One hundred and fifty-one C57BL/6 male mice underwent sham or endovascular perforation SAH operation, randomly followed by an intracerebroventricular infusion of vehicle or two dosages (117 or 585 ng) of a selective TLR4 antagonist IAXO-102 at 30 min post-operation. The effects were evaluated by survival rates, neurological scores, and brain water content at 24-72 h and immunoglobulin G immunostaining and Western blotting at 24 h post-SAH. IAXO-102 significantly prevented post-SAH neurological impairments, brain edema, and BBB disruption, resulting in improved survival rates. IAXO-102 also significantly suppressed post-SAH activation of a major isoform of MAPK p46 c-Jun N-terminal kinase (JNK) and matrix metalloproteinase-9 as well as periostin induction and preserved tight junction protein zona occludens-1. Another selective TLR4 antagonist TAK-242, which has a different binding site from IAXO-102, also showed similar effects to IAXO-102. This study first provided the evidence that TLR4 signaling is involved in post-SAH acute BBB disruption and that the signaling is mediated at least partly by JNK activation. TLR4-targeted therapy may be promising to reduce post-SAH morbidities and mortalities.

  20. Toll-like receptor 4 increases intestinal permeability through up-regulation of membrane PKC activity in alcoholic steatohepatitis.

    PubMed

    Li, Xin; Wang, Chen; Nie, Jiao; Lv, Dong; Wang, Tianyi; Xu, Youqing

    2013-09-01

    Intestinal hyperpermeability is a causal factor for the development of alcoholic endotoxemia and steatohepatitis. However, the mechanisms governing this link remain unknown. The purpose of this study was to determine whether toll-like receptor 4 (TLR4) is involved in ethanol's deleterious effects on the intestinal barrier. Caco-2 cells were incubated in vitro with 1-10% ethanol. The results indicated that ethanol had a dose-dependent effect in increasing TLR4 expression and intercellular permeability. Then the effects of TLR4 on protein kinase C (PKC) and the intercellular junction protein occludin were assessed with and without pretreatment with a TLR4 inhibitor. The results indicated that TLR4 increased nonspecific PKC activity and reduced the expression of phosphorylated occludin in the membrane, which increased intercellular permeability. These effects were prevented by pretreatment with TLR4 mAb. Wild-type C57BL/6 mice were fed an ethanol or isocaloric liquid diet for 6 weeks. Hepatitis was diagnosed by the presence of an associated elevated blood endotoxin level. Chronic ethanol treatment significantly elevated blood endotoxin levels, intestinal permeability, and the expression of TLR4 in the ileum and colon. Moreover, ethanol exposure reduced the distribution of phosphorylated occludin in the intestinal epithelium because of PKC activation. In conclusion, chronic ethanol exposure induces a high response of TLR4 to lipopolysaccharide (LPS), and TLR4 increases intestinal permeability through down-regulation of phosphorylated occludin expression in the intestinal epithelial barrier, accompanied by membrane PKC hyperactivity. Copyright © 2013 Elsevier Inc. All rights reserved.

  1. The Toll-Like Receptor 2/6 Agonist, FSL-1 Lipopeptide, Therapeutically Mitigates Acute Radiation Syndrome.

    PubMed

    Kurkjian, Cathryn J; Guo, Hao; Montgomery, Nathan D; Cheng, Ning; Yuan, Hong; Merrill, Joseph R; Sempowski, Gregory D; Brickey, W June; Ting, Jenny P-Y

    2017-12-11

    Risks of radiation exposure from nuclear incidents and cancer radiotherapy are undeniable realities. These dangers urgently compel the development of agents for ameliorating radiation-induced injuries. Biologic pathways mediated by myeloid differentiation primary response gene 88 (MyD88), the common adaptor for toll-like receptor (TLR) and Interleukin-1 receptor signaling, are critical for radioprotection. Treating with agonists prior to radiation enhances survival by activating TLR signaling, whereas radiomitigating TLR-activating therapeutics given after exposure are less defined. We examine the radiomitigation capability of TLR agonists and identify one that is superior for its efficacy and reduced toxic consequences compared to other tested agonists. We demonstrate that the synthetic TLR2/6 ligand Fibroblast-stimulating lipopeptide (FSL-1) substantially prolongs survival in both male and female mice when administered 24 hours after radiation and shows MyD88-dependent function. FSL-1 treatment results in accelerated hematopoiesis in bone marrow, spleen and periphery, and augments systemic levels of hematopoiesis-stimulating factors. The ability of FSL-1 to stimulate hematopoiesis is critical, as hematopoietic dysfunction results from a range of ionizing radiation doses. The efficacy of a single FSL-1 dose for alleviating radiation injury while protecting against adverse effects reveals a viable radiation countermeasures agent.

  2. Toll-like Receptors in the Vascular System: Sensing the Dangers Within

    PubMed Central

    McCarthy, Cameron G.; Webb, R. Clinton

    2016-01-01

    Toll-like receptors (TLRs) are components of the innate immune system that respond to exogenous infectious ligands (pathogen-associated molecular patterns, PAMPs) and endogenous molecules that are released during host tissue injury/death (damage-associated molecular patterns, DAMPs). Interaction of TLRs with their ligands leads to activation of downstream signaling pathways that induce an immune response by producing inflammatory cytokines, type I interferons (IFN), and other inflammatory mediators. TLR activation affects vascular function and remodeling, and these molecular events prime antigen-specific adaptive immune responses. Despite the presence of TLRs in vascular cells, the exact mechanisms whereby TLR signaling affects the function of vascular tissues are largely unknown. Cardiovascular diseases are considered chronic inflammatory conditions, and accumulating data show that TLRs and the innate immune system play a determinant role in the initiation and development of cardiovascular diseases. This evidence unfolds a possibility that targeting TLRs and the innate immune system may be a novel therapeutic goal for these conditions. TLR inhibitors and agonists are already in clinical trials for inflammatory conditions such as asthma, cancer, and autoimmune diseases, but their study in the context of cardiovascular diseases is in its infancy. In this article, we review the current knowledge of TLR signaling in the cardiovascular system with an emphasis on atherosclerosis, hypertension, and cerebrovascular injury. Furthermore, we address the therapeutic potential of TLR as pharmacological targets in cardiovascular disease and consider intriguing research questions for future study. PMID:26721702

  3. Palmitate induces VSMC apoptosis via toll like receptor (TLR)4/ROS/p53 pathway.

    PubMed

    Zhang, Yuanjun; Xia, Guanghao; Zhang, Yaqiong; Liu, Juxiang; Liu, Xiaowei; Li, Weihua; Lv, Yaya; Wei, Suhong; Liu, Jing; Quan, Jinxing

    2017-08-01

    Toll-like receptor 4 (TLR4) has been implicated in vascular inflammation, as well as in the pathogenesis of atherosclerosis and diabetes. Vascular smooth muscle cell (VSMC) apoptosis has been shown to induce plaque vulnerability in atherosclerosis. Previous studies reported that palmitate induced apoptosis in VSMCs; however, the role of TLR4 in palmitate-induced apoptosis in VSMCs has not yet been defined. In this study, we investigated whether or not palmitate-induced apoptosis depended on the activation of the TLR4 pathway. VSMCs were treated with or without palmitate, CRISPR/Cas9z-mediated genome editing methods were used to deplete TLR4 expression, while NADPH oxidase inhibitors were used to inhibit reactive oxygen species (ROS) generation. Cell apoptosis was detected by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay, ROS was measured using the 2',7'-dichlorodihydrofluorescein diacetate (DCFH-DA) method, the mRNA and protein expression levels of caspase 3, caspase 9, BCL-2 and p53 were studied by real-time polymerase chain reaction (RT-PCR) and ELISA. Palmitate significantly promotes VSMC apoptosis, ROS generation, and expression of caspase 3, caspase 9 and p53; while NADPH oxidase inhibitor pretreatment markedly attenuated these effects. Moreover, knockdown of TLR4 significantly blocked palmitate-induced ROS generation and VSMC apoptosis accompanied by inhibition of caspase 3, caspase 9, p53 expression and restoration of BCL-2 expression. Our results suggest that palmitate-induced apoptosis depends on the activation of the TLR4/ROS/p53 signaling pathway, and that TLR4 may be a potential therapeutic target for the prevention and treatment of atherosclerosis. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. Toll-like receptor 4 gene polymorphism modulates phenotypic expression in patients with hereditary hemochromatosis.

    PubMed

    Krayenbuehl, Pierre-Alexandre; Hersberger, Martin; Truninger, Kaspar; Müllhaupt, Beat; Maly, Friedrich E; Bargetzi, Mario; Schulthess, Georg

    2010-07-01

    Clinical penetrance of hereditary hemochromatosis is highly variable. We hypothesized that it might be modified by factors involved in the cellular immune response, such as toll-like receptors (TLRs) or nucleotide oligomerization domain proteins (NODs). Clinical expression of hemochromatosis was assessed as a function of TLR4, TLR9, and NOD2 polymorphisms in 99 homozygous carriers of the HFE C282Y mutation with mild-to-severe iron overload. Thirteen (13%) of the 99 hemochromatosis patients were heterozygous for a TLR4 Asp299Gly polymorphism and 86 (87%) were TLR4 wild-type-only carriers. Clinical expression of hemochromatosis was observed more frequently in carriers of the TLR4 polymorphism (100%) than in TLR4 wild-type carriers (56%, P = 0.002). This was based on higher prevalences of liver disease (92 vs. 45%, P = 0.002) and arthropathy of metacarpophalangeal joints (69 vs. 35%, P = 0.018) in TLR4 polymorphism carriers. The finding was strengthened by the strong association of TLR4 polymorphism with liver fibrosis in the subgroup of 52 patients who underwent a liver biopsy (P = 0.011). The TLR4 polymorphism did, however, not correlate with body iron overload. The study results remained significant in multiple regression analyses after excluding possible confounding effects, such as age, sex, alcohol, or meat intake, and in the subgroup of 84 patients presenting as the first members of their families. TLR4 Asp299Gly polymorphism modulates clinical expression in patients with hereditary hemochromatosis. The polymorphism does not correlate with iron overload suggesting that TLR4 plays a role in an inflammatory process arising from toxic effects of iron accumulation.

  5. Toll-like receptors and aseptic loosening of hip endoprosthesis-a potential to respond against danger signals?

    PubMed

    Lähdeoja, Tuomas; Pajarinen, Jukka; Kouri, Vesa-Petteri; Sillat, Tarvo; Salo, Jari; Konttinen, Yrjö T

    2010-02-01

    Bacterial remnants and subclinical biofilms residing on prosthesis surfaces have been speculated to play a role in hip implant loosening by opsonizing otherwise relatively inert wear particles. The innate immune system recognizes these microbial pathogen-associated molecular patterns (PAMPs) using Toll-like receptors (TLRs). Our objective was to evaluate the possible presence of TLRs in aseptic synovial membrane-like interface tissue. Bacterial culture-negative, aseptic (n = 4) periprosthetic synovial membrane-like tissue was compared to osteoarthritis synovial membrane (n = 5) for the presence of cells positive for all known human functional TLRs, stained using specific antibodies by immunohistochemistry, and evaluated using morphometry. In comparison to osteoarthtritic synovium, the number of TLR-positive cells was found to be increased in the aseptic setting, reflecting the considerable macrophage infiltration to the tissues investigated. Thus aseptic periprosthetic tissue seems to be very reactive to PAMPs. It has been recently recognized that TLR do not only respond to traditional PAMPs, but also to endogenous alarmings or danger signals released from necrotic and activated cells. Alarming-TLR interaction in the periprosthetic tissue might be a novel mechanism of aseptic loosening of endoprosthesis. (c) 2009 Orthopaedic Research Society.

  6. Toll-like receptors 9 and 3 as essential components of innate immune defense against mouse cytomegalovirus infection.

    PubMed

    Tabeta, Koichi; Georgel, Philippe; Janssen, Edith; Du, Xin; Hoebe, Kasper; Crozat, Karine; Mudd, Suzanne; Shamel, Louis; Sovath, Sosathya; Goode, Jason; Alexopoulou, Lena; Flavell, Richard A; Beutler, Bruce

    2004-03-09

    Several subsets of dendritic cells have been shown to produce type I IFN in response to viral infections, thereby assisting the natural killer cell-dependent response that eliminates the pathogen. Type I IFN production can be induced both by unmethylated CpG-oligodeoxynucleotide and by double-stranded RNA. Here, we describe a codominant CpG-ODN unresponsive phenotype that results from an N-ethyl-N-nitrosourea-induced missense mutation in the Tlr9 gene (Tlr9(CpG1)). Mice homozygous for the Tlr9(CpG1) allele are highly susceptible to mouse cytomegalovirus infection and show impaired infection-induced secretion of IFN-alpha/beta and natural killer cell activation. We also demonstrate that both the Toll-like receptor (TLR) 9 --> MyD88 and TLR3 --> Trif signaling pathways are activated in vivo on viral inoculation, and that each pathway contributes to innate defense against systemic viral infection. Whereas both pathways lead to type I IFN production, neither pathway offers full protection against mouse cytomegalovirus infection in the absence of the other. The Tlr9(CpG1) mutation alters a leucine-rich repeat motif and lies within a receptor domain that is conserved within the evolutionary cluster encompassing TLRs 7, 8, and 9. In other TLRs, including three mouse-specific TLRs described in this paper, the affected region is not represented. The phenotypic effect of the Tlr9(CpG1) allele thus points to a critical role for TLR9 in viral sensing and identifies a vulnerable amino acid within the ectodomain of three TLR proteins, essential for a ligand response.

  7. Migration ability and Toll-like receptor expression of human mesenchymal stem cells improves significantly after three-dimensional culture.

    PubMed

    Zhou, Panpan; Liu, Zilin; Li, Xue; Zhang, Bing; Wang, Xiaoyuan; Lan, Jing; Shi, Qing; Li, Dong; Ju, Xiuli

    2017-09-16

    While the conventional two-dimensional (2D) culture protocol is well accepted for the culture of mesenchymal stem cells (MSCs), this method fails to recapitulate the in vivo native three-dimensional (3D) cellular microenvironment, and may result in phenotypic changes, and homing and migration capacity impairments. MSC preparation in 3D culture systems has been considered an attractive preparatory and delivery method recently. We seeded human umbilical cord-derived MSCs (hUCMSCs) in a 3D culture system with porcine acellular dermal matrix (PADM), and investigated the phenotypic changes, the expression changes of some important receptors, including Toll-like receptors (TLRs) and C-X-C chemokine receptor type 4 (CXCR4) when hUCMSCs were transferred from 2D to 3D systems, as well as the alterations in in vivo homing and migration potential. It was found that the percentage of CD105-positive cells decreased significantly, whereas that of CD34- and CD271-positive cells increased significantly in 3D culture, compared to that in 2D culture. The mRNA and protein expression levels of TLR2, TLR3, TLR4, TLR6, and CXCR4 in hUCMSCs were increased significantly upon culturing with PADM for 3 days, compared to the levels in 2D culture. The numbers of migratory 3D hUCMSCs in the heart, liver, spleen, and bone marrow were significantly greater than the numbers of 2D hUCMSCs, and the worst migration occurred in 3D + AMD3100 (CXCR4 antagonist) hUCMSCs. These results suggested that 3D culture of hUCMSCs with PADM could alter the phenotypic characteristics of hUCMSCs, increase their TLR and CXCR4 expression levels, and promote their migratory and homing capacity in which CXCR4 plays an important role. Copyright © 2017 Elsevier Inc. All rights reserved.

  8. CBLB502, an agonist of Toll-like receptor 5, has antioxidant and scavenging free radicals activities in vitro.

    PubMed

    Li, Weiguang; Ge, Changhui; Yang, Liu; Wang, Ruixue; Lu, Yiming; Gao, Yan; Li, Zhihui; Wu, Yonghong; Zheng, Xiaofei; Wang, Zhaoyan; Zhang, Chenggang

    2016-01-01

    The bacterial protein flagellin is the known agonist of Toll-like receptor 5 (TLR5). It has been reported that CBLB502, a novel agonist of TLR5 derived from Salmonella flagellin, could reduce radiation toxicity in mouse and primate models, protect mice from dermatitis and oral mucositis caused by radiation, inhibit acute renal ischemic failure, and inhibit the growth of A549 lung cancer cell. The property of CBLB502 is able to bind to TLR5 and activates NF-κB signaling. In this study, we investigated the antioxidant potential and free radicals scavenging properties of CBLB502 in vitro. Interestingly, we found that CBLB502 has a direct and distinct antioxidant capacity and can efficiently scavenge a variety of free radicals, including superoxide anion, hydroxyl radical, and ABTS cation (ABTS(+)). Through wave scanning and kinetic evaluation of scavenging ABTS(+), we found that the ABTS(+) scavenging process of CBLB502 is relatively slow, and the ABTS(+) scavenging activity of CBLB502 has a consistently kinetics characteristics. In conclusion, our results suggested that CBLB502 has antioxidant and scavenging free radicals activities in vitro. It is implied that CBLB502 might partially promote the beneficial protective effect through its scavenging free radicals. Copyright © 2015. Published by Elsevier B.V.

  9. TBK1-targeted suppression of TRIF-dependent signaling pathway of Toll-like receptors by 6-shogaol, an active component of ginger.

    PubMed

    Park, Se-Jeong; Lee, Mi-Young; Son, Bu-Soon; Youn, Hyung-Sun

    2009-07-01

    Toll-like receptors (TLRs) are primary sensors that detect a wide variety of microbial components involving induction of innate immune responses. After recognition of microbial components, TLRs trigger the activation of myeloid differential factor 88 (MyD88) and Toll-interleukin-1 (IL-1) receptor domain-containing adapter inducing interferon-beta (TRIF)-dependent downstream signaling pathways. 6-Shoagol, an active ingredient of ginger, inhibits the MyD88-dependent signaling pathway by inhibiting inhibitor-kappaB kinase activity. Inhibitor-kappaB kinase is a key kinase in nuclear factor kappaB (NF-kappaB) activation. However, it is not known whether 6-shogaol inhibits the TRIF-dependent signaling pathway. Our goal was to identify the molecular target of 6-shogaol in the TRIF-dependent pathway of TLRs. 6-Shogaol inhibited the activation of interferon-regulatory factor 3 (IRF3) induced by lipopolysaccharide (LPS) and by polyriboinosinic polyribocytidylic acid (poly[I:C]), overexpression of TRIF, TANK-binding kinase1 (TBK1), and IRF3. Furthermore, 6-shogaol inhibited TBK1 activity in vitro. Together, these results suggest that 6-shogaol inhibits the TRIF-dependent signaling pathway of TLRs by targeting TBK1, and, they imply that 6-shogaol can modulate TLR-derived immune/inflammatory target gene expression induced by microbial infection.

  10. Toll-like receptor 6 and connective tissue growth factor are significantly upregulated in mitomycin-C-treated urothelial carcinoma cells under hydrostatic pressure stimulation.

    PubMed

    Chen, Shao-Kuan; Chung, Chih-Ang; Cheng, Yu-Che; Huang, Chi-Jung; Chen, Wen-Yih; Ruaan, Ruoh-Chyu; Li, Chuan; Tsao, Chia-Wen; Hu, Wei-Wen; Chien, Chih-Cheng

    2014-06-01

    Urothelial carcinoma (UC) is the most common histologic subtype of bladder cancer. The administration of mitomycin C (MMC) into the bladder after transurethral resection of the bladder tumor (TURBT) is a common treatment strategy for preventing recurrence after surgery. We previously applied hydrostatic pressure combined with MMC in UC cells and found that hydrostatic pressure synergistically enhanced MMC-induced UC cell apoptosis through the Fas/FasL pathways. To understand the alteration of gene expressions in UC cells caused by hydrostatic pressure and MMC, oligonucleotide microarray was used to explore all the differentially expressed genes. After bioinformatics analysis and gene annotation, Toll-like receptor 6 (TLR6) and connective tissue growth factor (CTGF) showed significant upregulation among altered genes, and their gene and protein expressions with each treatment of UC cells were validated by quantitative real-time PCR and immunoblotting. Under treatment with MMC and hydrostatic pressure, UC cells showed increasing apoptosis using extrinsic pathways through upregulation of TLR6 and CTGF.

  11. Enteroaggregative Escherichia coli flagellin-induced interleukin-8 secretion requires Toll-like receptor 5-dependent p38 MAP kinase activation

    PubMed Central

    Khan, Mohammed A S; Kang, Jian; Steiner, Theodore S

    2004-01-01

    Enteroaggregative Escherichia coli (EAEC) is an emerging enteric pathogen that causes acute and chronic diarrhoea in a number of clinical settings. EAEC diarrhoea involves bacterial aggregation, adherence to intestinal epithelial cells and elaboration of several toxigenic bacterial mediators. Flagellin (FliC-EAEC), a major bacterial surface protein of EAEC, causes interleukin (IL)-8 release from several epithelial cell lines. The host response to flagellins from E. coli and several other bacteria is mediated by Toll-like receptor 5 (TLR5), which signals through nuclear factor kappa B (NF-κB) to induce transcription of pro-inflammatory cytokines. p38 mitogen-activating protein (MAP) kinase (MAPK) is a member of a family of stress-related kinases that influences a diverse range of cellular functions including host inflammatory responses to microbial products. We studied the role of p38 MAPK in FliC-EAEC-induced IL-8 secretion from Caco-2 human intestinal epithelial cells and THP-1 human monocytic cells. We found that IL-8 secretion from both cell types is dependent on p38 MAPK, which is phospho-activated in response to FliC-EAEC. The role of TLR5 in p38 MAPK-dependent IL-8 secretion was verified in HEp-2 cells transiently transfected with a TLR5 expression construct. Activation of interleukin-1 receptor-associated kinase (IRAK) was also observed in Caco-2 and TLR5-transfected HEp-2 cells after exposure to FliC-EAEC. Finally, we demonstrated that pharmacological inhibition of p38 MAPK reduced IL-8 transcription and mRNA levels, but did not affect NF-κB activation. Collectively, our results suggest that TLR5 mediates p38 MAPK-dependent IL-8 secretion from epithelial and monocytic cells incubated with FliC-EAEC, and that this effect requires IL-8 promoter activation independent of NF-κB nuclear migration. PMID:15270737

  12. Mechanisms for the activation of Toll-like receptor 2/4 by saturated fatty acids and inhibition by docosahexaenoic acid.

    PubMed

    Hwang, Daniel H; Kim, Jeong-A; Lee, Joo Young

    2016-08-15

    Saturated fatty acids can activate Toll-like receptor 2 (TLR2) and TLR4 but polyunsaturated fatty acids, particularly docosahexaenoic acid (DHA) inhibit the activation. Lipopolysaccharides (LPS) and lipopetides, ligands for TLR4 and TLR2, respectively, are acylated by saturated fatty acids. Removal of these fatty acids results in loss of their ligand activity suggesting that the saturated fatty acyl moieties are required for the receptor activation. X-ray crystallographic studies revealed that these saturated fatty acyl groups of the ligands directly occupy hydrophobic lipid binding domains of the receptors (or co-receptor) and induce the dimerization which is prerequisite for the receptor activation. Saturated fatty acids also induce the dimerization and translocation of TLR4 and TLR2 into lipid rafts in plasma membrane and this process is inhibited by DHA. Whether saturated fatty acids induce the dimerization of the receptors by interacting with these lipid binding domains is not known. Many experimental results suggest that saturated fatty acids promote the formation of lipid rafts and recruitment of TLRs into lipid rafts leading to ligand independent dimerization of the receptors. Such a mode of ligand independent receptor activation defies the conventional concept of ligand induced receptor activation; however, this may enable diverse non-microbial molecules with endogenous and dietary origins to modulate TLR-mediated immune responses. Emerging experimental evidence reveals that TLRs play a key role in bridging diet-induced endocrine and metabolic changes to immune responses. Published by Elsevier B.V.

  13. Toll like receptor expression induced by exercise in obesity and metabolic syndrome: A systematic review.

    PubMed

    Rada, Isabel; Deldicque, Louise; Francaux, Marc; Zbinden-Foncea, Hermann

    2018-01-01

    Obesity and metabolic syndrome are disorders that correlate with the activation of pro-inflammatory pathways and cytokine production, to which Toll like receptors (TLR) contribute. Exercise may act as an anti-inflammatory modulator, but there is no consensus about the role of the TLR in this tuning. The present styudy aims to systematically review the current evidence on exercise-induced TLR regulation in animals and humans suffering from obesity and metabolic syndrome. Pubmed and Scopus databases were searched for publications from 1990 to September 2015. Search terms included: "Toll like Receptor", "TLR", "exercise", "obesity", "diabetes", and "metabolic syndrome". Elegibility criteria comprised: randomized control trials, cross-sectional and cohort studies; human or animal models with metabolic syndrome; any type of exercise; TLR expression measurement in any tissue by a clearly reported technique. The quality of selected studies was assessed using a modified version of the Downs and Black Quality Assessment Checklist. Data of study design; population; exercise type, timing and training elements; measurement technique, tissue analyzed and main outcome were extracted and categorized to facilitate data synthesis. 17 studies were included, of which 11 publications obtained a high, 5 a moderate and 1 a low score for quality assessment. A total of 8 human studies were analyzed: 6 studies used endurance continuous or interval training protocols, 1 study resistance training and the remaining study was performed following a marathon race. Blood cells were analyzed in seven studies, of which four studies sampled peripheral blood mononuclear cells (PBMC), three analyzed whole blood and one study sampled skeletal muscle. Nine animal studies were included: 8 used endurance training and 1 acute aerobic exercise. A variety of tissues samples were explored such as PBMC, skeletal muscle, adipose, vascular and nervous tissue. Globally, the animal studies showed a marked tendency

  14. Toll-Like Receptor 4 Is a Regulator of Monocyte and Electroencephalographic Responses to Sleep Loss

    PubMed Central

    Wisor, Jonathan P.; Clegern, William C.; Schmidt, Michelle A.

    2011-01-01

    Study Objectives: Sleep loss triggers changes in inflammatory signaling pathways in the brain and periphery. The mechanisms that underlie these changes are ill-defined. The Toll-like receptor 4 (TLR4) activates inflammatory signaling cascades in response to endogenous and pathogen-associated ligands known to be elevated in association with sleep loss. TLR4 is therefore a possible mediator of some of the inflammation-related effects of sleep loss. Here we describe the baseline electroencephalographic sleep phenotype and the biochemical and electroencephalographic responses to sleep loss in TLR4-deficient mice. Design, Measurements and Results: TLR4-deficient mice and wild type controls were subjected to electroencephalographic and electromyographic recordings during spontaneous sleep/wake cycles and during and after sleep restriction sessions of 3, 6, and 24-h duration, during which sleep was disrupted by an automated sleep restriction system. Relative to wild type control mice, TLR4-deficient mice exhibited an increase in the duration of the primary daily waking bout occurring at dark onset in a light/dark cycle. The amount of time spent in non-rapid eye movement sleep by TLR4-deficient mice was reduced in proportion to increased wakefulness in the hours immediately after dark onset. Subsequent to sleep restriction, EEG measures of increased sleep drive were attenuated in TLR4-deficient mice relative to wild-type mice. TLR4 was enriched 10-fold in brain cells positive for the cell surface marker CD11b (cells of the monocyte lineage) relative to CD11b-negative cells in wild type mouse brains. To assess whether this population was affected selectively by TLR4 knockout, flow cytometry was used to count F4/80- and CD45-positive cells in the brains of sleep deprived and time of day control mice. While wild-type mice exhibited a significant reduction in the number of CD11b-positive cells in the brain after 24-h sleep restriction, TLR4-deficient mice did not. Conclusion

  15. Expression and functionality of Toll-like receptor 3 in the megakaryocytic lineage

    PubMed Central

    D’Atri, L. P.; Etulain, J.; Rivadeneyra, L.; Lapponi, M. J.; Centurion, M.; Cheng, K.; Yin, H.; Schattner, M.

    2015-01-01

    Summary Background In addition to their key role in hemostasis, platelets and megakaryocytes also regulate immune and inflammatory responses, in part through their expression of Toll-like receptors (TLRs). Among the TLRs, TLR3 recognizes double-stranded (ds) RNA associated with viral infection. Thrombocytopenia is a frequent complication of viral infection. However, the expression and functionality of TLR3 in megakaryocytes and platelets is not yet well understood. Objective To study the expression and functionality of TLR3 in the megakaryocytic lineage. Methods and Results RT-PCR, flow cytometric, and immunofluorescence assays showed that TLR3 is expressed in CD34+ cells, megakaryocytes, and platelets. Immunoblotting assays showed that stimulation of megakaryocytes with two synthetic agonists of TLR3, Poly(I:C) and Poly(A:U), activated the NF-κB, PI3K/Akt, ERK1/2, and p38 pathways. TLR3-megakaryocyte activation resulted in reduced platelet production in vitro and IFN-β release through the PI3K/Akt and NF-κB signaling pathways. TLR3 ligands potentiated the aggregation mediated by classical platelet agonists. This effect was also observed for ATP release, but not for P-selectin or CD40L membrane exposure, indicating that TLR3 activation was not involved in alpha granule release. In addition, TLR3 agonists induced activation of the NF-κB, PI3K/Akt, and ERK1/2 pathways in platelets. Reduction of platelet production and platelet fibrinogen binding mediated by Poly(I:C) or Poly(A:U) were prevented by the presence of an inhibitor of TLR3/dsRNA complex. Conclusions Our findings indicate that functional TLR3 is expressed in CD34+ cells, megakaryocytes, and platelets, and suggest a potential role for this receptor in the megakaryo/thrombopoiesis alterations that occur in viral infections. PMID:25594115

  16. Presymptomatic differences in Toll-like receptor function in infants who have allergy.

    PubMed

    Prescott, Susan L; Noakes, Paul; Chow, Bonita W Y; Breckler, Liza; Thornton, Catherine A; Hollams, Elysia M; Ali, May; van den Biggelaar, Anita H J; Tulic, Meri K

    2008-08-01

    Microbial exposure might play a key role in allergy development, but little is known about the role of Toll-like receptors (TLRs). This study explored the association between neonatal TLR microbial recognition/function, allergy risk (maternal allergy), and prospective allergy development. Cord blood mononuclear cells (n = 111) were cultured either alone or with optimal concentrations of TLR ligands: lipoteichoic acid (TLR2), polyinosinicpolycytidylic acid (TLR3), LPS with IFN-gamma (TLR4), flagellin (TLR5), imiquimod R837 (TLR7), or CpG (TLR9). Cytokine responses were assessed in relation to allergy risk (maternal allergy) and allergy outcomes (sensitization, food allergy, and atopic dermatitis) at 12 months of age. Maternal allergy (n = 59) was associated with significantly higher neonatal IL-12 and IFN-gamma responses to TLR2, TLR3, and TLR4 activation, whereas TNF-alpha and IL-6 responses to TLR2, TLR4, and TLR5 activation were significantly higher in newborns who subsequently had allergic disease (n = 32). Notably, consistent with previous reports, newborns who had disease had lower T(H)1 IFN-gamma response to mitogens (PHA). Allergic disease was associated with increased (rather than decreased) perinatal TLR responses. Further studies are needed to determine how these responses track in the postnatal period and whether this relative hyperresponsiveness is a product of intrauterine influences, including maternal atopy, functional genetic polymorphisms, or both.

  17. Virus recognition by Toll-7 activates antiviral autophagy in Drosophila.

    PubMed

    Nakamoto, Margaret; Moy, Ryan H; Xu, Jie; Bambina, Shelly; Yasunaga, Ari; Shelly, Spencer S; Gold, Beth; Cherry, Sara

    2012-04-20

    Innate immunity is highly conserved and relies on pattern recognition receptors (PRRs) such as Toll-like receptors (identified through their homology to Drosophila Toll) for pathogen recognition. Although Drosophila Toll is vital for immune recognition and defense, roles for the other eight Drosophila Tolls in immunity have remained elusive. Here we have shown that Toll-7 is a PRR both in vitro and in adult flies; loss of Toll-7 led to increased vesicular stomatitis virus (VSV) replication and mortality. Toll-7, along with additional uncharacterized Drosophila Tolls, was transcriptionally induced by VSV infection. Furthermore, Toll-7 interacted with VSV at the plasma membrane and induced antiviral autophagy independently of the canonical Toll signaling pathway. These data uncover an evolutionarily conserved role for a second Drosophila Toll receptor that links viral recognition to autophagy and defense and suggest that other Drosophila Tolls may restrict specific as yet untested pathogens, perhaps via noncanonical signaling pathways. Copyright © 2012 Elsevier Inc. All rights reserved.

  18. Receptor-like kinase SOBIR1/EVR interacts with receptor-like proteins in plant immunity against fungal infection.

    PubMed

    Liebrand, Thomas W H; van den Berg, Grardy C M; Zhang, Zhao; Smit, Patrick; Cordewener, Jan H G; America, Antoine H P; America, Antione H P; Sklenar, Jan; Jones, Alexandra M E; Tameling, Wladimir I L; Robatzek, Silke; Thomma, Bart P H J; Joosten, Matthieu H A J

    2013-06-11

    The plant immune system is activated by microbial patterns that are detected as nonself molecules. Such patterns are recognized by immune receptors that are cytoplasmic or localized at the plasma membrane. Cell surface receptors are represented by receptor-like kinases (RLKs) that frequently contain extracellular leucine-rich repeats and an intracellular kinase domain for activation of downstream signaling, as well as receptor-like proteins (RLPs) that lack this signaling domain. It is therefore hypothesized that RLKs are required for RLPs to activate downstream signaling. The RLPs Cf-4 and Ve1 of tomato (Solanum lycopersicum) mediate resistance to the fungal pathogens Cladosporium fulvum and Verticillium dahliae, respectively. Despite their importance, the mechanism by which these immune receptors mediate downstream signaling upon recognition of their matching ligand, Avr4 and Ave1, remained enigmatic. Here we show that the tomato ortholog of the Arabidopsis thaliana RLK Suppressor Of BIR1-1/Evershed (SOBIR1/EVR) and its close homolog S. lycopersicum (Sl)SOBIR1-like interact in planta with both Cf-4 and Ve1 and are required for the Cf-4- and Ve1-mediated hypersensitive response and immunity. Tomato SOBIR1/EVR interacts with most of the tested RLPs, but not with the RLKs FLS2, SERK1, SERK3a, BAK1, and CLV1. SOBIR1/EVR is required for stability of the Cf-4 and Ve1 receptors, supporting our observation that these RLPs are present in a complex with SOBIR1/EVR in planta. We show that SOBIR1/EVR is essential for RLP-mediated immunity and propose that the protein functions as a regulatory RLK of this type of cell-surface receptors.

  19. Toll-like receptor 4 is involved in the cell cycle modulation and required for effective human cytomegalovirus infection in THP-1 macrophages

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Arcangeletti, Maria-Cristina, E-mail: mariacristina.arcangeletti@unipr.it; Germini, Diego; Rodighiero, Isabella

    2013-05-25

    Suitable host cell metabolic conditions are fundamental for the effective development of the human cytomegalovirus (HCMV) lytic cycle. Indeed, several studies have demonstrated the ability of this virus to interfere with cell cycle regulation, mainly by blocking proliferating cells in G1 or G1/S. In the present study, we demonstrate that HCMV deregulates the cell cycle of THP-1 macrophages (a cell line irreversibly arrested in G0) by pushing them into S and G2 phases. Moreover, we show that HCMV infection of THP-1 macrophages leads to Toll-like receptor 4 (TLR4) activation. Since various studies have indicated TLR4 to be involved in promotingmore » cell proliferation, here we investigate the possible role of TLR4 in the observed HCMV-induced cell cycle perturbation. Our data strongly support TLR4 as a mediator of HCMV-triggered cell cycle activation in THP-1 macrophages favouring, in turn, the development of an efficient viral lytic cycle. - Highlights: ► We studied HCMV infection impact on THP-1 macrophage cell cycle. ► We analysed the role played by Toll-like receptor (TLR) 4 upon HCMV infection. ► HCMV pushes THP-1 macrophages (i.e. resting cells) to re-enter the cell cycle. ► TLR4 pathway inhibition strongly affects the effectiveness of HCMV replication. ► TLR4 pathway inhibition significantly decreases HCMV-induced cell cycle re-entry.« less

  20. A tissue microarray study of toll-like receptor 4, decoy receptor 3, and external signal regulated kinase 1/2 expressions in astrocytoma.

    PubMed

    Lin, Chih-Kung; Ting, Chun-Chieh; Tsai, Wen-Chiuan; Chen, Yuan-Wu; Hueng, Dueng-Yuan

    2016-01-01

    Decoy receptor 3 (DcR3) functions as a death decoy inhibiting apoptosis mediated by the tumor necrosis factor receptor family. It is highly expressed in many tumors and its expression can be regulated by the MAPK/ERK signaling pathway and ERK is a vital member of this pathway. Toll-like receptor 4 (TLR4) is expressed on immune cells. Increased TLR4 expression has been associated with various types of cancers. The study was conducted to investigate the expression of DcR3, ERK1/2, and TLR4 in astrocytomas and evaluate if they are validating markers for discriminating glioblastoma from anaplastic astrocytoma in limited surgical specimen. Expression of DcR3, ERK1/2, and TLR4 was determined by immunohistochemical staining of tissue microarray from 48 paraffin-embedded tissues. A binary logistic regression method was used to generate functions that discriminate between anaplastic astrocytomas and glioblastomas. The expression of TLR4 and DcR3 was significantly higher in glioblastomas than in anaplastic astrocytomas. DcR3 could discriminate anaplastic astrocytomas from glioblastomas with high sensitivity (93.8%), specificity (90%), and accuracy (92.3%). Our results suggest that DcR3 may be a useful marker for discriminating anaplastic astrocytomas from glioblastomas.

  1. Toll/Interleukin-1 Receptor Domain Derived from TcpC (TIR-TcpC) Ameliorates Experimental Autoimmune Arthritis by Down-modulating Th17 Cell Response*

    PubMed Central

    Pasi, Shweta; Kant, Ravi; Surolia, Avadhesha

    2016-01-01

    Evasion through immunomodulation is one of the several strategies adopted by pathogens to prolong their survival within the host. One such pathogen, Escherichia coli CFT073, utilizes an immunomodulatory protein, TcpC, to combat the host's innate immune defense. TcpC abrogates the function of MyD88 in macrophages, thus perturbing all the signaling processes that involve this adaptor protein. Although central to various signaling pathways initiated by IL-1, IL-18, and toll-like receptors, the precise contribution of MyD88 to the development of autoimmunity, particularly rheumatoid arthritis, still needs extensive exploration. Herein, by using the toll/interleukin-1 receptor (TIR) domain homologous C-terminal motif of TcpC, i.e. TIR-TcpC, we found MyD88 to be critical for the induction and progression of rheumatoid arthritis through its pivotal role in the development of Th17 cells, the subset of CD4+ T-cells widely implicated in various autoimmune disorders. The TIR-TcpC mediated inhibition of signaling through MyD88, and subsequent amelioration of experimental autoimmune arthritis was observed to be an outcome of perturbations in the NFκB-RORγt (RAR-related orphan receptor γt) axis. PMID:27022030

  2. A Novel Approach for Effectively Treating SCI Pain, Improving Opioid Efficacy, and Preventing Opioid-Induced Constipation: Key Role of Toll-Like Receptor 4 (TLR4)

    DTIC Science & Technology

    2015-10-01

    University of Colorado Boulder, CO 80303 REPORT DATE: October 2015 TYPE OF REPORT: Annual PREPARED FOR: U.S. Army Medical Research and Materiel...TASK NUMBER 5f. WORK UNIT NUMBER 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) Regents of the University of Colorado Boulder, CO 80303 8...allodynia, hyperalgesia, toll-like receptor 4 OVERALL PROJECT SUMMARY Task 1. Obtain approval from the University of Colorado Institute Animal Care & Use

  3. Whey protein hydrolysates decrease IL-8 secretion in lipopolysaccharide (LPS)-stimulated respiratory epithelial cells by affecting LPS binding to Toll-like receptor 4.

    PubMed

    Iskandar, Michèle M; Dauletbaev, Nurlan; Kubow, Stan; Mawji, Nadir; Lands, Larry C

    2013-07-14

    Whey proteins (WP) exert anti-inflammatory and antioxidant effects. Hyperbaric pressurisation of whey increases its digestibility and changes the spectrum of peptides released during digestion. We have shown that dietary supplementation with pressurised whey improves nutritional status and systemic inflammation in patients with cystic fibrosis (CF). Both clinical indices are largely affected by airway processes, to which respiratory epithelial cells actively contribute. Here, we tested whether peptides released from the digestion of pressurised whey can attenuate the inflammatory responses of CF respiratory epithelial cells. Hydrolysates of pressurised WP (pWP) and native WP (nWP, control) were generated in vitro and tested for anti-inflammatory properties judged by the suppression of IL-8 production in CF and non-CF respiratory epithelial cell lines (CFTE29o- and 1HAEo-, respectively). We observed that, in both cell lines, pWP hydrolysate suppressed IL-8 production stimulated by lipopolysaccharide (LPS) to a greater magnitude compared with nWP hydrolysate. Neither hydrolysate suppressed IL-8 production induced by TNF-α or IL-1β, suggesting an effect on the Toll-like receptor (TLR) 4 pathway, the cellular sensor for LPS. Further, neither hydrolysate affected TLR4 expression or neutralised LPS. Both pWP and nWP hydrolysates similarly reduced LPS binding to surface TLR4, while pWP tended to more potently increase extracellular antioxidant capacity. (1) anti-inflammatory properties of whey are enhanced by pressurisation; (2) suppression of IL-8 production may contribute to the clinical effects of pressurised whey supplementation on CF; (3) this effect may be partly explained by a combination of reduced LPS binding to TLR4 and enhanced extracellular antioxidant capacity.

  4. Functional Toll-like receptor 4 expressed in lactotrophs mediates LPS-induced proliferation in experimental pituitary hyperplasia

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Sabatino, María Eugenia; Sosa, Liliana del Valle; Petiti, Juan Pablo

    Toll like receptor 4 (TLR4) has been characterized for its ability to recognize bacterial endotoxin lipopolysaccharide (LPS). Considering that infections or inflammatory processes might contribute to the progression of pituitary tumors, we analyzed the TLR4 functional role by evaluating the LPS effect on lactotroph proliferation in primary cultures from experimental pituitary tumors, and examined the involvement of PI3K-Akt and NF-κB activation in this effect. In addition, the role of 17β-estradiol as a possible modulator of LPS-induced PRL cell proliferation was further investigated. In estrogen-induced hyperplasic pituitaries, LPS triggered lactotroph cell proliferation. However, endotoxin failed to increase the number of lactotrophsmore » taking up BrdU in normal pituitaries. Moreover, incubation with anti-TLR4 antibody significantly reduced LPS-induced lactotroph proliferation, suggesting a functional role of this receptor. As a sign of TLR4 activation, an LPS challenge increased IL-6 release in normal and tumoral cells. By flow cytometry, TLR4 baseline expression was revealed at the plasma membrane of tumoral lactotrophs, without changes noted in the percentage of double PRL/TLR4 positive cells after LPS stimulus. Increases in TLR4 intracellular expression were detected as well as rises in CD14, p-Akt and NF-κB after an LPS challenge, as assessed by western blotting. The TLR4/PRL and PRL/NF-κB co-localization was also corroborated by immunofluorescence and the involvement of PI3K/Akt signaling in lactotroph proliferation and IL-6 release was revealed through the PI3K inhibitor Ly-294002. In addition, 17β-estradiol attenuated the LPS-evoked increase in tumoral lactotroph proliferation and IL-6 release. Collectively these results demonstrate the presence of functional TLR4 in lactotrophs from estrogen-induced hyperplasic pituitaries, which responded to the proliferative stimulation and IL-6 release induced by LPS through TLR4/CD14, with a contribution of

  5. Mangiferin inhibits lipopolysaccharide-induced production of interleukin-6 in human oral epithelial cells by suppressing toll-like receptor signaling.

    PubMed

    Li, Hao; Wang, Qi; Chen, Xinmin; Ding, Yi; Li, Wei

    2016-11-01

    Oral epithelial cells have currently been found to play an important role in inflammatory modulation in periodontitis. Mangiferin is a natural glucosylxanthone with anti-inflammatory activity. The aim of this study was to investigate the regulatory effect of mangiferin on lipopolysaccharide (LPS)-induced production of proinflammatory cytokine interleukin-6 (IL-6) in oral epithelial cells and the underlying mechanisms. The levels of LPS-induced IL-6 production in OKF6/TERT-2 oral keratinocytes were detected using enzyme-linked immunosorbent assay (ELISA). The expression of Toll-like receptor (TLR) 2 and TLR4 was determined using western blot analysis. And the phosphorylation of TLR downstream nuclear factor-κB (NF-κB), p38 mitogen-activated protein kinase (p38 MAPK) and c-Jun N-terminal kinase (JNK) was examined using cell-based protein phosphorylation ELISA kits. We found that mangiferin reduced LPS-upregulated IL-6 production in OKF6/TERT-2 cells. Additionally, mangiferin inhibited LPS-induced TLR2 and TLR4 overexpression, and suppressed the phosphorylation of NF-κB, p38 MAPK and JNK. Moreover, mangiferin repressed IL-6 production and TLR signaling activation in a dose-dependent manner after 24h treatment. Mangiferin decreases LPS-induced production of IL-6 in human oral epithelial cells by suppressing TLR signaling, and this glucosylxanthone may have potential for the treatment of periodontitis. Copyright © 2016 Elsevier Ltd. All rights reserved.

  6. Toll-like Receptor-4: A New Target for Preterm Labour Pharmacotherapies?

    PubMed

    Robertson, Sarah A; Wahid, Hanan H; Chin, Peck Yin; Hutchinson, Mark R; Moldenhauer, Lachlan M; Keelan, Jeffrey A

    2018-01-01

    Inflammatory activation, a major driver of preterm birth and subsequent neonatal morbidity, is an attractive pharmacological target for new preterm birth therapeutics. Inflammation elicited by intraamniotic infection is causally associated with preterm birth, particularly in infants delivered ≤34 weeks' gestation. However, sterile triggers of PTB, including placental ischaemic injury, uterine distention, cervical disease, or imbalance in the immune response, also act through inflammatory mediators released in response to tissue damage. Toll-like Receptors (TLRs) are critical upstream gate-keepers controlling the inflammatory activation that precedes preterm delivery, as well as in normal term labour. In particular, TLR4 is implicated for its capacity to sense and integrate a range of disparate infectious and sterile pro-inflammatory triggers, and so acts as a point-ofconvergence through which a range of infectious and sterile agents can activate and accelerate the parturition cascade. Recent studies point to the TLR4 signalling complex as a tractable target for the inhibition of fetal, placental & intraamniotic inflammatory cytokine production. Moreover, studies on mice show that novel small molecule antagonists of TLR4 signalling are highly effective in preventing preterm birth induced by bacterial mimetic LPS, heat-killed E. coli or the TLR4-dependent pro-inflammatory lipid, Platelet Activating Factor (PAF). In this review, we discuss the role of TLR4 in regulating the timing of birth and the potential utility of TLR4 antagonists as novel therapeutics for preterm delivery. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  7. The protective effect of the anti-Toll-like receptor 9 antibody against acute cytokine storm caused by immunostimulatory DNA.

    PubMed

    Murakami, Yusuke; Fukui, Ryutaro; Motoi, Yuji; Shibata, Takuma; Saitoh, Shin-Ichiroh; Sato, Ryota; Miyake, Kensuke

    2017-03-07

    Toll-like Receptor 9 (TLR9) is an innate immune receptor recognizing microbial DNA. TLR9 is also activated by self-derived DNA, such as mitochondrial DNA, in a variety of inflammatory diseases. We show here that TLR9 activation in vivo is controlled by an anti-TLR9 monoclonal Ab (mAb). A newly established mAb, named NaR9, clearly detects endogenous TLR9 expressed in primary immune cells. The mAb inhibited TLR9-dependent cytokine production in vitro by bone marrow-derived macrophages and conventional dendritic cells. Furthermore, NaR9 treatment rescued mice from fulminant hepatitis caused by administering the TLR9 ligand CpGB and D-(+)-galactosamine. The production of proinflammatory cytokines induced by CpGB and D-(+)-galactosamine was significantly impaired by the mAb. These results suggest that a mAb is a promising tool for therapeutic intervention in TLR9-dependent inflammatory diseases.

  8. Regulation of Toll-like receptor 2 interaction with Ecgp96 controls Escherichia coli K1 invasion of brain endothelial cells

    PubMed Central

    Krishnan, Subramanian; Chen, Shuang; Turcatel, Gianluca; Arditi, Moshe; Prasadarao, Nemani V.

    2012-01-01

    SUMMARY The interaction of outer membrane protein A (OmpA) with its receptor, Ecgp96 (a homologue of Hsp90β) is critical for the pathogenesis of E. coli K1 meningitis. Since Hsp90 chaperones Toll-like receptors (TLRs), we examined the role of TLRs in E. coli K1 infection. Herein, we show that newborn TLR2−/− mice are resistant to E. coli K1 meningitis, while TLR4−/− mice succumb to infection sooner. In vitro, OmpA+ E. coli infection selectively upregulates Ecgp96 and TLR2 in human brain microvascular endothelial cells (HBMEC), whereas OmpA− E. coli upregulates TLR4 in these cells. Furthermore, infection with OmpA+ E. coli causes Ecgp96 and TLR2 translocate to the plasma membrane of HBMEC as a complex. Immunoprecipitation studies of the plasma membrane fractions from infected HBMEC reveal that the C-termini of Ecgp96 and TLR2 are critical for OmpA+ E. coli invasion. Knockdown of TLR2 using siRNA results in inefficient membrane translocation of Ecgp96 and significantly reduces invasion. In addition, the interaction of Ecgp96 and TLR2 induces a bipartite signal, one from Ecgp96 through PKC-α while the other from TLR2 through MyD88, ERK1/2 and NF-κB. This bipartite signal ultimately culminates in the efficient production of NO, which in turn promotes E. coli K1 invasion of HBMEC. PMID:22963587

  9. Physical activity status, but not age, influences inflammatory biomarkers and toll-like receptor 4.

    PubMed

    McFarlin, Brian K; Flynn, Michael G; Campbell, Wayne W; Craig, Bruce A; Robinson, J Paul; Stewart, Laura K; Timmerman, Kyle L; Coen, Paul M

    2006-04-01

    Chronic inflammation has been implicated in the development of cardiovascular disease, diabetes mellitus, cachexia, and osteoporosis. Regular physical activity has been purported to possess "anti-inflammatory" properties which may limit chronic inflammation. Recently, we hypothesized that toll-like receptor 4 (TLR4) may play a role in activity-induced modulation of inflammation. Therefore, the purpose of this study was to determine the association between age, physical activity status, biomarkers of inflammation, and TLR4. Male and female participants (n = 84) were recruited to fill one of the following groups: young (18-30 years), active; young, inactive; old (60-80 years), active; or old, inactive. To assess physical activity status, participants completed a Paffenbarger Physical Activity Questionnaire and a modified Balke submaximal treadmill test. After grouping and screening, participants were given a standard mixed diet to consume 24 hours prior to arriving at the laboratory. Participants were instructed to consume all food by 10 pm the night prior to blood sampling (8-hour fast). Following 30 minutes of seated rest in a quiet room, venous blood samples were collected. Lipopolysaccharide-stimulated inflammatory cytokine production and plasma high-sensitivity C-reactive protein (hsCRP) were determined by enzyme-linked immunosorbent assay, and TLR4 expression was determined by flow cytometry. Lipopolysaccharide-stimulated interleukin-6, interleukin-1beta, and tumor necrosis factor-alpha production, TLR4 expression, and hsCRP were significantly lower in active compared to inactive participants (p <.05). Also, older participants had significantly higher hsCRP than young participants had (p <.05). The findings of the present study support previous reports which infer that acute exercise or a physically active lifestyle may possess anti-inflammatory properties. Also this study, along with previous work from our laboratory, suggests that TLR4 may play a role in

  10. Toll-like receptor 3 plays a role in myocardial infarction and ischemia/reperfusion injury.

    PubMed

    Lu, Chen; Ren, Danyang; Wang, Xiaohui; Ha, Tuanzhu; Liu, Li; Lee, Eric J; Hu, Jing; Kalbfleisch, John; Gao, Xiang; Kao, Race; Williams, David; Li, Chuanfu

    2014-01-01

    Innate immune and inflammatory responses mediated by Toll like receptors (TLRs) have been implicated in myocardial ischemia/reperfusion (I/R) injury. This study examined the role of TLR3 in myocardial injury induced by two models, namely, myocardial infarction (MI) and I/R. First, we examined the role of TLR3 in MI. TLR3 deficient (TLR3(-/-)) and wild type (WT) mice were subjected to MI induced by permanent ligation of the left anterior descending (LAD) coronary artery for 21days. Cardiac function was measured by echocardiography. Next, we examined whether TLR3 contributes to myocardial I/R injury. TLR3(-/-) and WT mice were subjected to myocardial ischemia (45min) followed by reperfusion for up to 3days. Cardiac function and myocardial infarct size were examined. We also examined the effect of TLR3 deficiency on I/R-induced myocardial apoptosis and inflammatory cytokine production. TLR3(-/-) mice showed significant attenuation of cardiac dysfunction after MI or I/R. Myocardial infarct size and myocardial apoptosis induced by I/R injury were significantly attenuated in TLR3(-/-) mice. TLR3 deficiency increases B-cell lymphoma 2 (BCL2) levels and attenuates I/R-increased Fas, Fas ligand or CD95L (FasL), Fas-Associated protein with Death Domain (FADD), Bax and Bak levels in the myocardium. TLR3 deficiency also attenuates I/R-induced myocardial nuclear factor KappaB (NF-κB) binding activity, Tumor necrosis factor alpha (TNF-α) and Interleukin-1 beta (IL-1β) production as well as I/R-induced infiltration of neutrophils and macrophages into the myocardium. TLR3 plays an important role in myocardial injury induced by MI or I/R. The mechanisms involve activation of apoptotic signaling and NF-κB binding activity. Modulation of TLR3 may be an effective approach for ameliorating heart injury in heart attack patients. © 2013.

  11. Transforming growth factor-β and toll-like receptor-4 polymorphisms are not associated with fibrosis in haemochromatosis

    PubMed Central

    Wood, Marnie J; Powell, Lawrie W; Dixon, Jeannette L; Subramaniam, V Nathan; Ramm, Grant A

    2013-01-01

    AIM: To investigate the role of genetic polymorphisms in the progression of hepatic fibrosis in hereditary haemochromatosis. METHODS: A cohort of 245 well-characterised C282Y homozygous patients with haemochromatosis was studied, with all subjects having liver biopsy data and DNA available for testing. This study assessed the association of eight single nucleotide polymorphisms (SNPs) in a total of six genes including toll-like receptor 4 (TLR4), transforming growth factor-beta (TGF-β), oxoguanine DNA glycosylase, monocyte chemoattractant protein 1, chemokine C-C motif receptor 2 and interleukin-10 with liver disease severity. Genotyping was performed using high resolution melt analysis and sequencing. The results were analysed in relation to the stage of hepatic fibrosis in multivariate analysis incorporating other cofactors including alcohol consumption and hepatic iron concentration. RESULTS: There were significant associations between the cofactors of male gender (P = 0.0001), increasing age (P = 0.006), alcohol consumption (P = 0.0001), steatosis (P = 0.03), hepatic iron concentration (P < 0.0001) and the presence of hepatic fibrosis. Of the candidate gene polymorphisms studied, none showed a significant association with hepatic fibrosis in univariate or multivariate analysis incorporating cofactors. We also specifically studied patients with hepatic iron loading above threshold levels for cirrhosis and compared the genetic polymorphisms between those with no fibrosis vs cirrhosis however there was no significant effect from any of the candidate genes studied. Importantly, in this large, well characterised cohort of patients there was no association between SNPs for TGF-β or TLR4 and the presence of fibrosis, cirrhosis or increasing fibrosis stage in multivariate analysis. CONCLUSION: In our large, well characterised group of haemochromatosis subjects we did not demonstrate any relationship between candidate gene polymorphisms and hepatic fibrosis or

  12. Transforming growth factor-β and toll-like receptor-4 polymorphisms are not associated with fibrosis in haemochromatosis.

    PubMed

    Wood, Marnie J; Powell, Lawrie W; Dixon, Jeannette L; Subramaniam, V Nathan; Ramm, Grant A

    2013-12-28

    To investigate the role of genetic polymorphisms in the progression of hepatic fibrosis in hereditary haemochromatosis. A cohort of 245 well-characterised C282Y homozygous patients with haemochromatosis was studied, with all subjects having liver biopsy data and DNA available for testing. This study assessed the association of eight single nucleotide polymorphisms (SNPs) in a total of six genes including toll-like receptor 4 (TLR4), transforming growth factor-beta (TGF-β), oxoguanine DNA glycosylase, monocyte chemoattractant protein 1, chemokine C-C motif receptor 2 and interleukin-10 with liver disease severity. Genotyping was performed using high resolution melt analysis and sequencing. The results were analysed in relation to the stage of hepatic fibrosis in multivariate analysis incorporating other cofactors including alcohol consumption and hepatic iron concentration. There were significant associations between the cofactors of male gender (P = 0.0001), increasing age (P = 0.006), alcohol consumption (P = 0.0001), steatosis (P = 0.03), hepatic iron concentration (P < 0.0001) and the presence of hepatic fibrosis. Of the candidate gene polymorphisms studied, none showed a significant association with hepatic fibrosis in univariate or multivariate analysis incorporating cofactors. We also specifically studied patients with hepatic iron loading above threshold levels for cirrhosis and compared the genetic polymorphisms between those with no fibrosis vs cirrhosis however there was no significant effect from any of the candidate genes studied. Importantly, in this large, well characterised cohort of patients there was no association between SNPs for TGF-β or TLR4 and the presence of fibrosis, cirrhosis or increasing fibrosis stage in multivariate analysis. In our large, well characterised group of haemochromatosis subjects we did not demonstrate any relationship between candidate gene polymorphisms and hepatic fibrosis or cirrhosis.

  13. Toll-like receptor 7 promotes the apoptosis of THP-1-derived macrophages through the CHOP-dependent pathway.

    PubMed

    Yu, Xiaochen; Wang, Yang; Zhao, Wenhui; Zhou, Haizhou; Yang, Wei; Guan, Xiuru

    2014-09-01

    Macrophage apoptosis is a prominent characteristic of advanced atherosclerotic plaques and leads to plaque destabilization. Certain studies have confirmed that influenza virus A (IVA) infection is related to acute myocardial infarction (AMI). However, it remains unknown as to whether this phenomenon is associated with Toll-like receptor (TLR)7, since single-stranded RNA (ssRNA) of IVA is a natural ligand of TLR7. Thus, in the present study, THP-1‑derived macrophages were infected with IVA or treated with imiquimod (IMQ) in the presence or absence of pre-treatment with oxidized low-density lipoprotein (oxLDL). The macrophages were pre-treated with oxLDL (5 µg/ml) for 24 h to mimic high lipid conditions. Cell viability and apoptosis were detected by 3-(4,5-dimethylthiazol-2-y-1)‑2,5-diphenyl-2H-tetrazolium bromide (MTT) assay and flow cytometry, respectively. Our results revealed that TLR7 played an important role in macrophage apoptosis and cytokine secretion. Both IVA infection and IMQ treatment increased TLR7 expression, as well as the secretion of pro-inflammatory cytokines [interleukin (IL)-6, monocyte chemotactic protein (MCP)-1] and apoptosis. However, this increase in cytokine secretion occurred independently of cell apoptosis. oxLDL had potential synergistic pro-apoptotic effects combined with TLR7 activation. To determine whether endoplasmic reticulum (ER) stress plays a role in cell apoptosis, the mRNA and protein expression of known markers of ER stress [glucose-regulated protein (GRP)78 and C/EBP homologous protein (CHOP)] was detected by reverse transcription PCR (RT-PCR), quantitative reverse transcription PCR (qRT-PCR) and western blot analysis. Our results revealed that apoptosis aggravated ER stress, as shown by the overexpression of the pro-apoptotic sensor, CHOP. In conclusion, our study demonstrates the converging role of oxLDL pre-treatment, IVA infection and IMQ in ER stress-induced cell apoptosis.

  14. Local activation of uterine Toll-like receptor 2 and 2/6 decreases embryo implantation and affects uterine receptivity in mice.

    PubMed

    Sanchez-Lopez, Javier Arturo; Caballero, Ignacio; Montazeri, Mehrnaz; Maslehat, Nasim; Elliott, Sarah; Fernandez-Gonzalez, Raul; Calle, Alexandra; Gutierrez-Adan, Alfonso; Fazeli, Alireza

    2014-04-01

    Embryo implantation is a complex interaction between maternal endometrium and embryonic structures. Failure to implant is highly recurrent and impossible to diagnose. Inflammation and infections in the female reproductive tract are common causes of infertility, embryo loss, and preterm labor. The current work describes how the activation of endometrial Toll-like receptor (TLR) 2 and 2/6 reduces embryo implantation chances. We developed a morphometric index to evaluate the effects of the TLR 2/6 activation along the uterine horn (UH). TLR 2/6 ligation reduced the endometrial myometrial and glandular indexes and increased the luminal index. Furthermore, TLR 2/6 activation increased the proinflammatory cytokines such as interleukin (IL)-1beta and monocyte chemotactic protein (MCP)-1 in UH lavages in the preimplantation day and IL-1 receptor antagonist in the implantation day. The engagement of TLR 2/6 with its ligand in the UH during embryo transfer severely affected the rate of embryonic implantation (45.00% ± 6.49% vs. 16.69% ± 5.01%, P < 0.05, control vs. test, respectively). Furthermore, this interference with the embryo implantation process was verified using an in vitro model of human embryo implantation where trophoblast spheroids failed to adhere to a monolayer of TLR 2- and TLR 2/6-activated endometrial cells. The inhibition of TLR receptors 2 and 6 in the presence of their specific ligands restored the ability of the spheroids to bind to the endometrial cells. In conclusion, the activation of the innate immune system in the uterus at the time of implantation interfered with the endometrial receptivity and reduced the chances of implantation success.

  15. The expression of Toll-like receptors 2, 4, 5, 7 and 9 in Merkel cell carcinoma.

    PubMed

    Jouhi, Lauri; Koljonen, Virve; Böhling, Tom; Haglund, Caj; Hagström, Jaana

    2015-04-01

    We sought to clarify whether the expression of toll-like receptors (TLR) in Merkel cell carcinoma (MCC) is linked to tumor and patient characteristics, especially the presence of Merkel cell polyoma virus (MCV). The study comprised of 128 patients with data on Merkel cell polyomavirus (MCV) status and clinical features were included in the study. Immunohistochemistry for TLR expression was performed on tissue microarray (TMA) slides. TLR 2, 4, 5, 7 and 9 expression was noted in most of the tumor specimens. Decreased expression of TLR 9 correlated strongly with MCV positivity. Cytoplasmic TLR 2 expression correlated with small tumor size, while nuclear TLR 2 and TLR 5 expressions with larger tumors. Increased nuclear TLR 4 expression and decreased TLR 7 expression were associated with older age. TLR 2, 4, 5, 7 and 9 appear to reflect certain clinicopathological variables and prognostic markers of MCC tumors. Copyright© 2015 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved.

  16. Role of Toll-like receptor 4 signaling in cutaneous chronic graft-versus-host disease.

    PubMed

    Weng, Jianyu; Lai, Peilong; Geng, Suxia; Luo, Chenwei; Wu, Suijing; Ling, Wei; Deng, Chengxin; Huang, Xin; Lu, Zesheng; Du, Xin

    2015-06-01

    Cutaneous damage is one of the characterized manifestations in chronic graft-versus-host disease (cGVHD). When local effective immunity in the skin is altered to a dysimmune reaction, cutaneous injuries occur. Toll-like receptor 4 signaling is regarded as a central mediator of inflammation and organ injury. In this study, we found that TLR4 mRNA in peripheral blood from patients with cutaneous cGVHD was markedly increased compared with that from non-GVHD patients and healthy controls. In addition, NF-κB expression, TLR4 downstream signaling, and TLR4-mediated cytokines, including IL-6 and ICAM-1, were upregulated. Moreover, ICAM-1 was widely distributed in skin biopsies from patients with cutaneous cGVHD. We also found that LPS induced TLR4-mediated NF-κB activation and IL-6 and ICAM-1 secretion in human fibroblasts in vitro. Thus, TLR4, NF-κB, IL-6, and ICAM-1 contribute to the inflammatory response that occurs in cutaneous cGVHD, indicating the TLR4 pathway may be a novel target for cutaneous cGVHD therapy. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  17. Key Role of CD36 in Toll-Like Receptor 2 Signaling in Cerebral Ischemia

    PubMed Central

    Abe, Takato; Shimamura, Munehisa; Jackman, Katherine; Kurinami, Hitomi; Anrather, Josef; Zhou, Ping; Iadecola, Costantino

    2010-01-01

    Background and Purpose Toll-like receptors (TLRs) and the scavenger receptor CD36 are key molecular sensors for the innate immune response to invading pathogens. However, these receptors may also recognize endogenous “danger signals” generated during brain injury, such as cerebral ischemia, and trigger a maladaptive inflammatory reaction. Indeed, CD36 and TLR2 and 4 are involved in the inflammation and related tissue damage caused by brain ischemia. Because CD36 may act as a coreceptor for TLR2 heterodimers (TLR2/1 or TLR2/6), we tested whether such interaction plays a role in ischemic brain injury. Methods The TLR activators FSL-1 (TLR2/6), Pam3 (TLR2/1), or lipopolysaccharide (TLR4) were injected intracerebroventricularly into wild-type or CD36-null mice, and inflammatory gene expression was assessed in the brain. The effect of TLR activators on the infarct produced by transient middle cerebral artery occlusion was also studied. Results The inflammatory response induced by TLR2/1 activation, but not TLR2/6 or TLR4 activation, was suppressed in CD36-null mice. Similarly, TLR2/1 activation failed to increase infarct volume in CD36-null mice, whereas TLR2/6 or TLR4 activation exacerbated postischemic inflammation and increased infarct volume. In contrast, the systemic inflammatory response evoked by TLR2/6 activation, but not by TLR2/1 activation, was suppressed in CD36-null mice. Conclusions In the brain, TLR2/1 signaling requires CD36. The cooperative signaling of TLR2/1 and CD36 is a critical factor in the inflammatory response and tissue damage evoked by cerebral ischemia. Thus, suppression of CD36-TLR2/1 signaling could be a valuable approach to minimize postischemic inflammation and the attendant brain injury. PMID:20360550

  18. Damage-associated molecular pattern activated Toll-like receptor 4 signalling modulates blood pressure in L-NAME-induced hypertension.

    PubMed

    Sollinger, Daniel; Eißler, Ruth; Lorenz, Steffen; Strand, Susanne; Chmielewski, Stefan; Aoqui, Cristiane; Schmaderer, Christoph; Bluyssen, Hans; Zicha, Josef; Witzke, Oliver; Scherer, Elias; Lutz, Jens; Heemann, Uwe; Baumann, Marcus

    2014-03-01

    Recent publications have shed new light on the role of the adaptive and innate immune system in the pathogenesis of hypertension. However, there are limited data whether receptors of the innate immune system may influence blood pressure. Toll-like receptor 4 (TLR4), a pattern recognition receptor, is a key component of the innate immune system, which is activated by exogenous and endogenous ligands. Hypertension is associated with end-organ damage and thus might lead to the release of damage-associated molecular patterns (DAMPs), which are endogenous activators of TLR4 receptors. The present study aimed to elucidate whether TLR4 signalling is able to modulate vascular contractility in an experimental model of hypertension thus contributing to blood pressure regulation. NG-nitro-l-arginine methyl ester (l-NAME)-induced hypertension was blunted in TLR4(-/-) when compared with wild-type mice. Treatment with l-NAME was associated with a release of DAMPs, leading to reactive oxygen species production of smooth muscle cells in a TLR4-dependent manner. As oxidative stress leads to an impaired function of the NO-sGC-cyclic GMP (cGMP) pathway, we were able to demonstrate that TLR4(-/-) was protected from sGC inactivation. Consequently, arterial contractility was reduced in TLR4(-/-). Cell damage-associated TLR4 signalling might act as a direct mediator of vascular contractility providing a molecular link between inflammation and hypertension.

  19. Toll-like receptor, lipotoxicity and chronic inflammation: the pathological link between obesity and cardiometabolic disease.

    PubMed

    Eguchi, Kosei; Manabe, Ichiro

    2014-01-01

    The epidemic growth in the prevalence of obesity has made the impact of metabolic syndrome on cardiovascular events increasingly significant. Elevated visceral adiposity, the indispensable component of metabolic syndrome, is thought to play a primary role in the increasing incidence of cardiometabolic disorders. Importantly, obesity is not merely the simple expansion of adipose tissue mass; it also involves the activation of inflammatory processes within visceral adipose tissue. Adipose tissue inflammation on the one hand enhances the production of proinflammatory adipokines and on the other hand increases the release of free fatty acids via the activation of lipolysis. The adipokines and free fatty acids secreted from visceral fat then contribute to a cardiometabolic pathology. We herein summarize recent advances in our understanding of the mechanisms by which visceral obesity leads to the activation of inflammation in cardiovascular and metabolic tissues and promotes cardiometabolic disease. Our focus is on Toll-like receptor 4 signaling and free fatty acids as mediators of chronic inflammation in patients with metabolic syndrome and atherosclerosis.

  20. Toll-Like Receptor 4 Mediates Methamphetamine-Induced Neuroinflammation through Caspase-11 Signaling Pathway in Astrocytes

    PubMed Central

    Du, Si-Hao; Qiao, Dong-Fang; Chen, Chuan-Xiang; Chen, Si; Liu, Chao; Lin, Zhoumeng; Wang, Huijun; Xie, Wei-Bing

    2017-01-01

    Methamphetamine (METH) is an amphetamine-typed stimulant drug that is increasingly being abused worldwide. Previous studies have shown that METH toxicity is systemic, especially targeting dopaminergic neurons in the central nervous system (CNS). However, the role of neuroinflammation in METH neurotoxicity remains unclear. We hypothesized that Toll-like receptor 4 (TLR4) and Caspase-11 are involved in METH-induced astrocyte-related neuroinflammation. We tested our hypothesis by examining the changes of TLR4 and Caspase-11 protein expression in primary cultured C57BL/6 mouse astrocytes and in the midbrain and striatum of mice exposed to METH with western blot and double immunofluorescence labeling. We also determined the effects of blocking Caspase-11 expression with wedelolactone (a specific inhibitor of Caspase-11) or siRNA on METH-induced neuroinflammation in astrocytes. Furthermore, we determined the effects of blocking TLR4 expression with TAK-242 (a specific inhibitor of TLR4) or siRNA on METH-induced neuroinflammation in astrocytes. METH exposure increased Caspase-11 and TLR4 expression both in vitro and in vivo, with the effects in vitro being dose-dependent. Inhibition of Caspase-11 expression with either wedelolactone or siRNAs reduced the expression of inflammasome NLRP3 and pro-inflammatory cytokines. In addition, blocking TLR4 expression inhibited METH-induced activation of NF-κB and Caspase-11 in vitro and in vivo, suggesting that TLR4-Caspase-11 pathway is involved in METH-induced neuroinflammation. These results indicate that Caspase-11 and TLR4 play an important role in METH-induced neuroinflammation and may be potential gene targets for therapeutics in METH-caused neurotoxicity. PMID:29311802

  1. Rotavirus Activates Lymphocytes from Non-Obese Diabetic Mice by Triggering Toll-Like Receptor 7 Signaling and Interferon Production in Plasmacytoid Dendritic Cells

    PubMed Central

    Pane, Jessica A.; Webster, Nicole L.; Coulson, Barbara S.

    2014-01-01

    It has been proposed that rotavirus infection promotes the progression of genetically-predisposed children to type 1 diabetes, a chronic autoimmune disease marked by infiltration of activated lymphocytes into pancreatic islets. Non-obese diabetic (NOD) mice provide a model for the human disease. Infection of adult NOD mice with rhesus monkey rotavirus (RRV) accelerates diabetes onset, without evidence of pancreatic infection. Rather, RRV spreads to the pancreatic and mesenteric lymph nodes where its association with antigen-presenting cells, including dendritic cells, induces cellular maturation. RRV infection increases levels of the class I major histocompatibility complex on B cells and proinflammatory cytokine expression by T cells at these sites. In autoimmunity-resistant mice and human mononuclear cells from blood, rotavirus-exposed plasmacytoid dendritic cells contribute to bystander polyclonal B cell activation through type I interferon expression. Here we tested the hypothesis that rotavirus induces bystander activation of lymphocytes from NOD mice by provoking dendritic cell activation and proinflammatory cytokine secretion. NOD mouse splenocytes were stimulated with rotavirus and assessed for activation by flow cytometry. This stimulation activated antigen-presenting cells and B cells independently of virus strain and replicative ability. Instead, activation depended on virus dose and was prevented by blockade of virus decapsidation, inhibition of endosomal acidification and interference with signaling through Toll-like receptor 7 and the type I interferon receptor. Plasmacytoid dendritic cells were more efficiently activated than conventional dendritic cells by RRV, and contributed to the activation of B and T cells, including islet-autoreactive CD8+ T cells. Thus, a double-stranded RNA virus can induce Toll-like receptor 7 signaling, resulting in lymphocyte activation. Our findings suggest that bystander activation mediated by type I interferon

  2. Biglycan, a danger signal that activates the NLRP3 inflammasome via toll-like and P2X receptors.

    PubMed

    Babelova, Andrea; Moreth, Kristin; Tsalastra-Greul, Wasiliki; Zeng-Brouwers, Jinyang; Eickelberg, Oliver; Young, Marian F; Bruckner, Peter; Pfeilschifter, Josef; Schaefer, Roland M; Gröne, Hermann-Josef; Schaefer, Liliana

    2009-09-04

    The role of endogenous inducers of inflammation is poorly understood. To produce the proinflammatory master cytokine interleukin (IL)-1beta, macrophages need double stimulation with ligands to both Toll-like receptors (TLRs) for IL-1beta gene transcription and nucleotide-binding oligomerization domain-like receptors for activation of the inflammasome. It is particularly intriguing to define how this complex regulation is mediated in the absence of an infectious trigger. Biglycan, a ubiquitous leucine-rich repeat proteoglycan of the extracellular matrix, interacts with TLR2/4 on macrophages. The objective of this study was to define the role of biglycan in the synthesis and activation of IL-1beta. Here we show that in macrophages, soluble biglycan induces the NLRP3/ASC inflammasome, activating caspase-1 and releasing mature IL-1beta without the need for additional costimulatory factors. This is brought about by the interaction of biglycan with TLR2/4 and purinergic P2X(4)/P2X(7) receptors, which induces receptor cooperativity. Furthermore, reactive oxygen species formation is involved in biglycan-mediated activation of the inflammasome. By signaling through TLR2/4, biglycan stimulates the expression of NLRP3 and pro-IL-1beta mRNA. Both in a model of non-infectious inflammatory renal injury (unilateral ureteral obstruction) and in lipopolysaccharide-induced sepsis, biglycan-deficient mice displayed lower levels of active caspase-1 and mature IL-1beta in the kidney, lung, and circulation. Our results provide evidence for direct activation of the NLRP3 inflammasome by biglycan and describe a fundamental paradigm of how tissue stress or injury is monitored by innate immune receptors detecting the release of the extracellular matrix components and turning such a signal into a robust inflammatory response.

  3. Discovery and Validation of a New Class of Small Molecule Toll-Like Receptor 4 (TLR4) Inhibitors

    PubMed Central

    Neal, Matthew D.; Jia, Hongpeng; Eyer, Benjamin; Good, Misty; Guerriero, Christopher J.; Sodhi, Chhinder P.; Afrazi, Amin; Prindle, Thomas; Ma, Congrong; Branca, Maria; Ozolek, John; Brodsky, Jeffrey L.; Wipf, Peter; Hackam, David J.

    2013-01-01

    Many inflammatory diseases may be linked to pathologically elevated signaling via the receptor for lipopolysaccharide (LPS), toll-like receptor 4 (TLR4). There has thus been great interest in the discovery of TLR4 inhibitors as potential anti-inflammatory agents. Recently, the structure of TLR4 bound to the inhibitor E5564 was solved, raising the possibility that novel TLR4 inhibitors that target the E5564-binding domain could be designed. We utilized a similarity search algorithm in conjunction with a limited screening approach of small molecule libraries to identify compounds that bind to the E5564 site and inhibit TLR4. Our lead compound, C34, is a 2-acetamidopyranoside (MW 389) with the formula C17H27NO9, which inhibited TLR4 in enterocytes and macrophages in vitro, and reduced systemic inflammation in mouse models of endotoxemia and necrotizing enterocolitis. Molecular docking of C34 to the hydrophobic internal pocket of the TLR4 co-receptor MD-2 demonstrated a tight fit, embedding the pyran ring deep inside the pocket. Strikingly, C34 inhibited LPS signaling ex-vivo in human ileum that was resected from infants with necrotizing enterocolitis. These findings identify C34 and the β-anomeric cyclohexyl analog C35 as novel leads for small molecule TLR4 inhibitors that have potential therapeutic benefit for TLR4-mediated inflammatory diseases. PMID:23776545

  4. Role of Thr399Ile and Asp299Gly polymorphisms of toll-like receptor-4 gene in acute dental abscess.

    PubMed

    Miri-Moghaddam, Ebrahim; Farhad-Mollashahi, Narges; Baghaee, Elnaz; Bazi, Ali; Garme, Yasaman

    2017-02-01

    Apical Periodontitis (AP) is an inflammatory disease that affects the tissues surrounding the root end of a tooth. The disease which is caused by endodontic infections presents in different clinical ways including development of an acute abscess. Recent studies have provided information suggesting role of a multitude of factors in pathogenesis of acute apical abscess (AAA). In this case-control study, our goal was to evaluate the frequency and potential role of two common polymorphisms of toll like receptor-4 (TLR-4) gene; Thr399Ile (1196 C>T) and Asp299Gly (+896 A>G), in 50 patients with AAA as cases and 50 patients with asymptomatic apical periodontitis (AAP) as controls. Saliva sample containing mucosal epithelial cells was used for DNA extraction. Polymorphisms were detected by Tetra-ARMS (Amplification Refractory Mutation System) PCR method. Statistical analyses were carried out in SPSS 21 software. Homozygous wild type (CC) and heterozygous (CT) genotypes of Thr399Ile polymorphism were detected in 84% and 16% of AAA patients respectively. In controls, respective ratios were 94% (CC) and 6% (CT). Observed difference was not statistically significant ( P >0.05) for distribution of these genotypes. The mutant homozygous (TT) genotype of this polymorphism was identified in neither of the participants. Overall, T allele frequency was obtained 8% in AAA and 3% in AAP (OR=2.6, 95% CI; 0. 6-10.6, p >0.05). For Asp299Gly polymorphism, no individual was detected with the mutant allele in case or control groups. Our results indicated a possible role for Thr399Ile polymorphism in acute presentations of abscess in AAA. However, the impact of this polymorphism needs to be more assessed in future studies. Key words: Genetic polymorphism, periapical abscess, periapical periodontitis, toll-like receptor 4.

  5. Role of Thr399Ile and Asp299Gly polymorphisms of toll-like receptor-4 gene in acute dental abscess

    PubMed Central

    Miri-Moghaddam, Ebrahim; Baghaee, Elnaz; Bazi, Ali; Garme, Yasaman

    2017-01-01

    Background Apical Periodontitis (AP) is an inflammatory disease that affects the tissues surrounding the root end of a tooth. The disease which is caused by endodontic infections presents in different clinical ways including development of an acute abscess. Recent studies have provided information suggesting role of a multitude of factors in pathogenesis of acute apical abscess (AAA). In this case-control study, our goal was to evaluate the frequency and potential role of two common polymorphisms of toll like receptor-4 (TLR-4) gene; Thr399Ile (1196 C>T) and Asp299Gly (+896 A>G), in 50 patients with AAA as cases and 50 patients with asymptomatic apical periodontitis (AAP) as controls. Material and Methods Saliva sample containing mucosal epithelial cells was used for DNA extraction. Polymorphisms were detected by Tetra-ARMS (Amplification Refractory Mutation System) PCR method. Statistical analyses were carried out in SPSS 21 software. Results Homozygous wild type (CC) and heterozygous (CT) genotypes of Thr399Ile polymorphism were detected in 84% and 16% of AAA patients respectively. In controls, respective ratios were 94% (CC) and 6% (CT). Observed difference was not statistically significant (P>0.05) for distribution of these genotypes. The mutant homozygous (TT) genotype of this polymorphism was identified in neither of the participants. Overall, T allele frequency was obtained 8% in AAA and 3% in AAP (OR=2.6, 95% CI; 0. 6-10.6, p>0.05). For Asp299Gly polymorphism, no individual was detected with the mutant allele in case or control groups. Conclusions Our results indicated a possible role for Thr399Ile polymorphism in acute presentations of abscess in AAA. However, the impact of this polymorphism needs to be more assessed in future studies. Key words:Genetic polymorphism, periapical abscess, periapical periodontitis, toll-like receptor 4. PMID:28210435

  6. Toll-like receptor 2-independent host innate immune response against an epidemic strain of Streptococcus suis that causes a toxic shock-like syndrome in humans.

    PubMed

    Lachance, Claude; Segura, Mariela; Gerber, Pehuén Pereyra; Xu, Jianguo; Gottschalk, Marcelo

    2013-01-01

    Streptococcus suis is an emerging zoonotic agent causing meningitis and septicemia. Outbreaks in humans in China with atypical cases of streptococcal toxic shock-like syndrome have been described to be caused by a clonal epidemic S. suis strain characterized as sequence type (ST) 7 by multilocus sequence typing, different from the classical ST1 usually isolated in Europe. Previous in vitro studies showed that Toll-like receptor (TLR) 2 plays a major role in S. suis ST1 interactions with host cells. In the present study, the in vivo role of TLR2 in systemic infections caused by S. suis ST1 or ST7 strains using TLR2 deficient (TLR2(-/-)) mice was evaluated. TLR2-mediated recognition significantly contributes to the acute disease caused by the highly virulent S. suis ST1 strain, since the TLR2(-/-) mice remained unaffected when compared to wild type (WT) mice. The lack of mortality could not be associated with a lower bacterial burden; however, a significant decrease in the induction of pro-inflammatory mediators, as evaluated by microarray, real-time PCR and protein assays, was observed. On the other hand, TLR2(-/-) mice infected with the epidemic ST7 strain presented no significant differences regarding survival and expression of pro-inflammatory mediators when compared to the WT mice. Together, these results show a TLR2-independent host innate immune response to S. suis that depends on the strain.

  7. A tetrapod-like repertoire of innate immune receptors and effectors for coelacanths

    USGS Publications Warehouse

    Boudinot, Pierre; Zou, Jun; Ota, Tatsuya; Buonocore, Francesco; Scapigliati, Giuseppe; Canapa, Adriana; Cannon, John; Litman, Gary; Hansen, John D.

    2014-01-01

    The recent availability of both robust transcriptome and genome resources for coelacanth (Latimeria chalumnae) has led to unique discoveries for coelacanth immunity such as the lack of IgM, a central component of adaptive immunity. This study was designed to more precisely address the origins and evolution of gene families involved in the initial recognition and response to microbial pathogens, which effect innate immunity. Several multigene families involved in innate immunity are addressed, including: Toll-like receptors (TLRs), retinoic acid inducible gene 1 (RIG1)-like receptors (RLRs), the nucleotide-binding domain and leucine-rich repeat containing proteins (NLRs), diverse immunoglobulin domain-containing proteins (DICP) and modular domain immune-type receptors (MDIRs). Our analyses also include the tripartite motif-containing proteins (TRIM), which are involved in pathogen recognition as well as the positive regulation of antiviral immunity. Finally, this study addressed some of the downstream effectors of the antimicrobial response including IL-1 family members, type I and II interferons (IFN) and IFN-stimulated effectors (ISGs). Collectively, the genes and gene families in coelacanth that effect innate immune functions share characteristics both in content, structure and arrangement with those found in tetrapods but not in teleosts. The findings support the sister group relationship of coelacanth fish with tetrapods.

  8. Human Lipopolysaccharide-binding Protein (LBP) and CD14 Independently Deliver Triacylated Lipoproteins to Toll-like Receptor 1 (TLR1) and TLR2 and Enhance Formation of the Ternary Signaling Complex*

    PubMed Central

    Ranoa, Diana Rose E.; Kelley, Stacy L.; Tapping, Richard I.

    2013-01-01

    Bacterial lipoproteins are the most potent microbial agonists for the Toll-like receptor 2 (TLR2) subfamily, and this pattern recognition event induces cellular activation, leading to host immune responses. Triacylated bacterial lipoproteins coordinately bind TLR1 and TLR2, resulting in a stable ternary complex that drives intracellular signaling. The sensitivity of TLR-expressing cells to lipoproteins is greatly enhanced by two lipid-binding serum proteins known as lipopolysaccharide-binding protein (LBP) and soluble CD14 (sCD14); however, the physical mechanism that underlies this increased sensitivity is not known. To address this, we measured the ability of LBP and sCD14 to drive ternary complex formation between soluble extracellular domains of TLR1 and TLR2 and a synthetic triacylated lipopeptide agonist. Importantly, addition of substoichiometric amounts of either LBP or sCD14 significantly enhanced formation of a TLR1·TLR2 lipopeptide ternary complex as measured by size exclusion chromatography. However, neither LBP nor sCD14 was physically associated with the final ternary complex. Similar results were obtained using outer surface protein A (OspA), a naturally occurring triacylated lipoprotein agonist from Borrelia burgdorferi. Activation studies revealed that either LBP or sCD14 sensitized TLR-expressing cells to nanogram levels of either the synthetic lipopeptide or OspA lipoprotein agonist. Together, our results show that either LBP or sCD14 can drive ternary complex formation and TLR activation by acting as mobile carriers of triacylated lipopeptides or lipoproteins. PMID:23430250

  9. Toll like Receptor 2 engagement on CD4+ T cells promotes TH9 differentiation and function.

    PubMed

    Karim, Ahmad Faisal; Reba, Scott M; Li, Qing; Boom, W Henry; Rojas, Roxana E

    2017-09-01

    We have recently demonstrated that mycobacterial ligands engage Toll like receptor 2 (TLR2) on CD4 + T cells and up-regulate T-cell receptor (TCR) triggered Th1 responses in vitro and in vivo. To better understand the role of T-cell expressed TLR2 on CD4 + T-cell differentiation and function, we conducted a gene expression analysis of murine naïve CD4 + T-cells stimulated in the presence or absence of TLR2 co-stimulation. Unexpectedly, naïve CD4 + T-cells co-stimulated via TLR2 showed a significant up-regulation of Il9 mRNA compared to cells co-stimulated via CD28. Under TH9 differentiation, we observed up-regulation of TH9 differentiation, evidenced by increases in both percent of IL-9 secreting cells and IL-9 in culture supernatants in the presence of TLR2 agonist both in polyclonal and Ag85B cognate peptide specific stimulations. Under non-polarizing conditions, TLR2 engagement on CD4 + T-cells had minimal effect on IL-9 secretion and TH9 differentiation, likely due to a prominent effect of TLR2 signaling on IFN-γ secretion and TH1 differentiation. We also report that, TLR2 signaling in CD4 + T cells increased expression of transcription factors BATF and PU.1, known to positively regulate TH9 differentiation. These results reveal a novel role of T-cell expressed TLR2 in enhancing the differentiation and function of TH9 T cells. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Mouse macrophages primed with alendronate down-regulate monocyte chemoattractant protein-1 (MCP-1) and macrophage inflammatory protein-1alpha (MIP-1alpha) production in response to Toll-like receptor (TLR) 2 and TLR4 agonist via Smad3 activation.

    PubMed

    Masuda, Takahiro; Deng, Xue; Tamai, Riyoko

    2009-08-01

    Alendronate is one of the nitrogen-containing bisphosphonates (NBPs) used as anti-bone resorptive drugs. However, NBPs have inflammatory side effects including osteomyelitis and osteonecrosis of the jaw. In the present study, we examined the effects of alendronate on chemokine production by the macrophage-like cell line, J774.1, when incubated with Pam(3)CSK(4) (a Toll-like receptor (TLR) 2 agonist) and Lipid A (a TLR4 agonist). Pretreatment of J774.1 cells with alendronate decreased the production of TLR ligand-induced monocyte chemoattractant protein-1 (MCP-1) and macrophage inflammatory protein-1alpha (MIP-1alpha) but did not influence nuclear factor-kappaB (NF-kappaB) activation. While this agent induced caspase-8 activation, a caspase-8 inhibitor did not affect the decrease in MCP-1 production by alendronate and TLR ligands. Thus, the alendronate-mediated decrease in chemokine production was independent of NF-kappaB and caspase-8 activation. Although transforming growth factor-beta1 (TGF-beta1) is known to inhibit chemokine production by various cell types via Smad3 activation, pretreatment with alendronate did not increase TGF-beta1 production by J774.1 cells incubated in the presence or absence of TLR ligands. However, alendronate directly activated Smad3. These results suggest that by down-regulating MCP-1 and MIP-1alpha production via Smad3, long-term use of alendronate might inhibit normal activation and migration of osteoclasts and cause osteonecrosis.

  11. Toll-Like Receptor 2 Stimulation of Osteoblasts Mediates Staphylococcus Aureus Induced Bone Resorption and Osteoclastogenesis through Enhanced RANKL

    PubMed Central

    Kassem, Ali; Lindholm, Catharina; Lerner, Ulf H

    2016-01-01

    Severe Staphylococcus aureus (S. aureus) infections pose an immense threat to population health and constitute a great burden for the health care worldwide. Inter alia, S. aureus septic arthritis is a disease with high mortality and morbidity caused by destruction of the infected joints and systemic bone loss, osteoporosis. Toll-Like receptors (TLRs) are innate immune cell receptors recognizing a variety of microbial molecules and structures. S. aureus recognition via TLR2 initiates a signaling cascade resulting in production of various cytokines, but the mechanisms by which S. aureus causes rapid and excessive bone loss are still unclear. We, therefore, investigated how S. aureus regulates periosteal/endosteal osteoclast formation and bone resorption. S. aureus stimulation of neonatal mouse parietal bone induced ex vivo bone resorption and osteoclastic gene expression. This effect was associated with increased mRNA and protein expression of receptor activator of NF-kB ligand (RANKL) without significant change in osteoprotegerin (OPG) expression. Bone resorption induced by S. aureus was abolished by OPG. S. aureus increased the expression of osteoclastogenic cytokines and prostaglandins in the parietal bones but the stimulatory effect of S. aureus on bone resorption and Tnfsf11 mRNA expression was independent of these cytokines and prostaglandins. Stimulation of isolated periosteal osteoblasts with S. aureus also resulted in increased expression of Tnfsf11 mRNA, an effect lost in osteoblasts from Tlr2 knockout mice. S. aureus stimulated osteoclastogenesis in isolated periosteal cells without affecting RANKL-stimulated resorption. In contrast, S. aureus inhibited RANKL-induced osteoclast formation in bone marrow macrophages. These data show that S. aureus enhances bone resorption and periosteal osteoclast formation by increasing osteoblast RANKL production through TLR2. Our study indicates the importance of using different in vitro approaches for studies of how S

  12. Adenovirus Modulates Toll-Like Receptor 4 Signaling by Reprogramming ORP1L-VAP Protein Contacts for Cholesterol Transport from Endosomes to the Endoplasmic Reticulum.

    PubMed

    Cianciola, Nicholas L; Chung, Stacey; Manor, Danny; Carlin, Cathleen R

    2017-03-15

    Human adenoviruses (Ads) generally cause mild self-limiting infections but can lead to serious disease and even be fatal in high-risk individuals, underscoring the importance of understanding how the virus counteracts host defense mechanisms. This study had two goals. First, we wished to determine the molecular basis of cholesterol homeostatic responses induced by the early region 3 membrane protein RIDα via its direct interaction with the sterol-binding protein ORP1L, a member of the evolutionarily conserved family of oxysterol-binding protein (OSBP)-related proteins (ORPs). Second, we wished to determine how this interaction regulates innate immunity to adenovirus. ORP1L is known to form highly dynamic contacts with endoplasmic reticulum-resident VAP proteins that regulate late endosome function under regulation of Rab7-GTP. Our studies have demonstrated that ORP1L-VAP complexes also support transport of LDL-derived cholesterol from endosomes to the endoplasmic reticulum, where it was converted to cholesteryl esters stored in lipid droplets when ORP1L was bound to RIDα. The virally induced mechanism counteracted defects in the predominant cholesterol transport pathway regulated by the late endosomal membrane protein Niemann-Pick disease type C protein 1 (NPC1) arising during early stages of viral infection. However, unlike NPC1, RIDα did not reconstitute transport to endoplasmic reticulum pools that regulate SREBP transcription factors. RIDα-induced lipid trafficking also attenuated proinflammatory signaling by Toll-like receptor 4, which has a central role in Ad pathogenesis and is known to be tightly regulated by cholesterol-rich "lipid rafts." Collectively, these data show that RIDα utilizes ORP1L in a way that is distinct from its normal function in uninfected cells to fine-tune lipid raft cholesterol that regulates innate immunity to adenovirus in endosomes. IMPORTANCE Early region 3 proteins encoded by human adenoviruses that attenuate immune

  13. The innate immune sensor NLRC3 attenuates Toll-like receptor signaling via modification of the signaling adaptor TRAF6 and transcription factor NF-κB.

    PubMed

    Schneider, Monika; Zimmermann, Albert G; Roberts, Reid A; Zhang, Lu; Swanson, Karen V; Wen, Haitao; Davis, Beckley K; Allen, Irving C; Holl, Eda K; Ye, Zhengmao; Rahman, Adeeb H; Conti, Brian J; Eitas, Timothy K; Koller, Beverly H; Ting, Jenny P-Y

    2012-09-01

    Several members of the NLR family of sensors activate innate immunity. In contrast, we found here that NLRC3 inhibited Toll-like receptor (TLR)-dependent activation of the transcription factor NF-κB by interacting with the TLR signaling adaptor TRAF6 to attenuate Lys63 (K63)-linked ubiquitination of TRAF6 and activation of NF-κB. We used bioinformatics to predict interactions between NLR and TRAF proteins, including interactions of TRAF with NLRC3. In vivo, macrophage expression of Nlrc3 mRNA was diminished by the administration of lipopolysaccharide (LPS) but was restored when cellular activation subsided. To assess biologic relevance, we generated Nlrc3(-/-) mice. LPS-treated Nlrc3(-/-) macrophages had more K63-ubiquitinated TRAF6, nuclear NF-κB and proinflammatory cytokines. Finally, LPS-treated Nlrc3(-/-) mice had more signs of inflammation. Thus, signaling via NLRC3 and TLR constitutes a negative feedback loop. Furthermore, prevalent NLR-TRAF interactions suggest the formation of a 'TRAFasome' complex.

  14. Toll-like receptor 7 agonists are potent and rapid bronchodilators in guinea pigs

    PubMed Central

    Kaufman, Elad H.; Fryer, Allison D.; Jacoby, David B.

    2011-01-01

    Background Respiratory tract viral infections result in asthma exacerbations. Toll-like receptor (TLR) 7 is a receptor for viral single-stranded RNA and is expressed at high levels in the lungs. Objective Because TLR7 polymorphisms are associated with asthma, we examined the effects of TLR7 agonists in guinea pig airways. Methods We induced bronchoconstriction in guinea pigs in vivo by means of electrical stimulation of the vagus nerve or intravenous administration of acetylcholine and measured the effect of a TLR7 agonist administered intravenously. We induced contraction of airway smooth muscle in segments of isolated guinea pig tracheas in vitro and measured the effect of TLR7 agonists, antagonists, and pharmacologic inhibitors of associated signaling pathways administered directly to the bath. Results TLR7 agonists acutely inhibited bronchoconstriction in vivo and relaxed contraction of airway smooth muscle in vitro within minutes of administration. Airway relaxation induced by the TLR7 agonist R837 (imiquimod) was partially blocked with a TLR7 antagonist and was also blocked by inhibitors of large-conductance, calcium-activated potassium channels; prostaglandin synthesis; and nitric oxide generation. Another TLR7 agonist, 21-mer single-stranded phosphorothioated polyuridylic acid (PolyUs), mediated relaxation that was completely blocked by a TLR7 antagonist. Conclusions These data demonstrate a novel protective mechanism to limit bronchoconstriction and maintain airflow during respiratory tract viral infections. The fast time frame is inconsistent with canonical TLR7 signaling. R837 mediates bronchodilation by means of TLR7-dependent and TLR7-independent mechanisms, whereas PolyUs does so through only the TLR7-dependent mechanism. TLR7-independent mechanisms involve prostaglandins and large-conductance, calcium-activated potassium channels, whereas TLR7-dependent mechanisms involve nitric oxide. TLR7 is an attractive therapeutic target for its ability to

  15. Toll like receptor 2 and 4 polymorphisms in malaria endemic populations of India.

    PubMed

    Bali, Prerna; Pradhan, Sabyasachi; Sharma, Divya; Adak, Tridibes

    2013-02-01

    Toll like receptors (TLRs) play a pivotal role in recognizing the invading malaria parasite Plasmodium, thus genetic makeup of the exposed population can be of utmost importance for its predisposition to malaria. In this study 264 malaria patients from seven different eco epidemiological regions of India were genotyped for TLR2 and TLR4 polymorphisms using DNA sequencing methods. No variation was observed at residue positions 677 and 753 in TLR2 whereas residue positions 299 and 399 in TLR4 were highly polymorphic. The GC haplotype (Asp299Gly/Thr399Thr) was observed at the highest frequency in populations of East Singhbhum, Vizianagaram and North Goa and absent in Kolkata, Dakshin Kannada and Nicobar district. All polymorphisms were in Hardy Weinberg equilibrium. Populations of Kolkata, Nicobar district, Sundergarh and Dakshin Kannada were observed to be closely related. TLR2 polymorphism was absent in the Indian population and an overall heterogeneous pattern of TLR4 polymorphism can be attributed to genetic drift. However it can be inferred that GC haplotype is under the process of natural selection in the Indian population and one of the factors contributing to its selection could be predominance of Plasmodium falciparum in these regions. Copyright © 2012 American Society for Histocompatibility and Immunogenetics. Published by Elsevier Inc. All rights reserved.

  16. Effect of baicalin on toll-like receptor 4-mediated ischemia/reperfusion inflammatory responses in alcoholic fatty liver condition

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Kim, Seok-Joo; Lee, Sun-Mee, E-mail: sunmee@skku.edu

    Alcoholic fatty liver is susceptible to secondary stresses such as ischemia/reperfusion (I/R). Baicalin is an active component extracted from Scutellaria baicalensis, which is widely used in herbal preparations for treatment of hepatic diseases and inflammatory disorders. This study evaluated the potential beneficial effect of baicalin on I/R injury in alcoholic fatty liver. Rats were fed an alcohol liquid diet or a control isocaloric diet for 5 weeks, and then subjected to 60 min of hepatic ischemia and 5 h of reperfusion. Baicalin (200 mg/kg) was intraperitoneally administered 24 and 1 h before ischemia. After reperfusion, baicalin attenuated the increases inmore » serum alanine aminotransferase activity, tumor necrosis factor-α (TNF-α), and interleukin-6 (IL-6) levels in alcoholic fatty liver. The increased levels of TNF-α and IL-6 mRNA expression and inducible nitric oxide synthase and cyclooxygenase-2 protein and mRNA expressions increased after reperfusion, which were higher in ethanol-fed animals, were attenuated by baicalin. In ethanol-fed animals, baicalin attenuated the increases in toll-like receptor 4 (TLR4) and myeloid differentiation factor 88 protein expressions and the nuclear translocation of NF-κB after reperfusion. In conclusion, our findings suggest that baicalin ameliorates I/R-induced hepatocellular damage by suppressing TLR4-mediated inflammatory responses in alcoholic fatty liver. -- Highlights: ► Baicalin attenuates hepatic I/R-induced inflammation in alcoholic fatty liver. ► Baicalin downregulates TLR4, MyD88 expression during I/R in alcoholic fatty liver. ► Baicalin attenuates NF-κB nuclear translocation during I/R in alcoholic fatty liver.« less

  17. Antagonists of toll like receptor 4 maybe a new strategy to counteract opioid-induced hyperalgesia and opioid tolerance.

    PubMed

    Li, Qian

    2012-12-01

    Long term opioid treatment results in hyperalgesia and tolerance, which is a troublesome phenomenon in clinic application. Recent studies have revealed a critical role of toll-like receptor 4 (TLR4) in the neuropathological process of opioid-induced hyperalgesia and tolerance. TLR4 is predominantly expressed by microglial cells and is a key modulator in the activation of the innate immune system. Activation of TLR4 may initiate the activation of microglia and hence a number of neurotransmitters and neuromodulators that could enhance neuronal excitability are released. Blockade of TLR4 activation by its antagonists alleviate neuropathic pain. We hypothesized that opioid antagonists such as naloxone and naltrexone, which were also demonstrated to be TLR4 antagonist, may have clinic application value in attenuation of opioid-induced hyperalgesia and tolerance. Copyright © 2012 Elsevier Ltd. All rights reserved.

  18. Alternate-day fasting protects the livers of mice against high-fat diet-induced inflammation associated with the suppression of Toll-like receptor 4/nuclear factor κB signaling.

    PubMed

    Yang, Wanwei; Cao, Meng; Mao, Xiaodong; Wei, Xiao; Li, Xingjia; Chen, Guofang; Zhang, Jiaming; Wang, Zhiguo; Shi, Jianfeng; Huang, HouCai; Yao, Xiaoming; Liu, Chao

    2016-06-01

    Because of unhealthy lifestyles, a large number of people are suffering from hepatic lipid accumulation and nonalcoholic steatohepatitis. Energy restriction (ER) is an effective nutritional intervention for preventing chronic disease. However, poor compliance with continuous ER limits its effectiveness. As an alternative to daily ER, alternate-day fasting (ADF) may be more effective. We hypothesized that ADF would improve obesity, hyperglycemia, and insulin resistance and protect the liver against high-fat diet (HFD)-induced steatosis and inflammation. In this study, we used C57BL/6 mice to test the beneficial effects of ADF. Thirty male 6-week-old C57BL/6 mice were divided into 3 groups (10 per group, total N = 30): 1 group was fed chow diet, the second was fed HFD ad libitum, and the third group was submitted to ADF. The mice in the third group were fed the HFD ad libitum every other day and fasted the following day. After 12 months, the mice submitted to ADF exhibited reduced body weights and fasting glucose levels and improved insulin resistance and hepatic steatosis compared with continuous HFD-fed mice. In addition, the serum transaminase levels in the mice of the ADF group were lower than those of the HFD group. Moreover, the ADF regimen suppressed the expression levels of Toll-like receptor 4 and nuclear factor κB protein in the liver and suppressed the inflammatory pathway genes interleukin 1β, tumor necrosis factor α, and serum amyloid A. These finding indicate that long-term ADF protects mouse livers against HFD-induced hepatic steatosis and hepatocellular damage associated with the suppression of Toll-like receptor 4/nuclear factor κB signaling. Copyright © 2016 Elsevier Inc. All rights reserved.

  19. Hypoxia preconditioning increases survival and decreases expression of Toll-like receptor 4 in pulmonary artery endothelial cells exposed to lipopolysaccharide.

    PubMed

    Ali, Irshad; Nanchal, Rahul; Husnain, Fouad; Audi, Said; Konduri, G Ganesh; Densmore, John C; Medhora, Meetha; Jacobs, Elizabeth R

    2013-09-01

    Abstract Pulmonary or systemic infections and hypoxemic respiratory failure are among the leading causes of admission to intensive care units, and these conditions frequently exist in sequence or in tandem. Inflammatory responses to infections are reproduced by lipopolysaccharide (LPS) engaging Toll-like receptor 4 (TLR4). Apoptosis is a hallmark of lung injury in sepsis. This study was conducted to determine whether preexposure to LPS or hypoxia modulated the survival of pulmonary artery endothelial cells (PAECs). We also investigated the role TLR4 receptor expression plays in apoptosis due to these conditions. Bovine PAECs were cultured in hypoxic or normoxic environments and treated with LPS. TLR4 antagonist TAK-242 was used to probe the role played by TLR4 receptors in cell survival. Cell apoptosis and survival were measured by caspase 3 activity and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) incorporation. TLR4 expression and tumor necrosis factor α (TNF-α) production were also determined. LPS increased caspase 3 activity in a TAK-242-sensitive manner and decreased MTT incorporation. Apoptosis was decreased in PAECs preconditioned with hypoxia prior to LPS exposure. LPS increased TNF-α production, and hypoxic preconditioning blunted it. Hypoxic preconditioning reduced LPS-induced TLR4 messenger RNA and TLR4 protein. TAK-242 decreased to baseline the LPS-stimulated expression of TLR4 messenger RNA regardless of environmental conditions. In contrast, LPS followed by hypoxia substantially increased apoptosis and cell death. In conclusion, protection from LPS-stimulated PAEC apoptosis by hypoxic preconditioning is attributable in part to reduction in TLR4 expression. If these signaling pathways apply to septic patients, they may account for differing sensitivities of individuals to acute lung injury depending on oxygen tensions in PAECs in vivo.

  20. Hypoxia preconditioning increases survival and decreases expression of Toll-like receptor 4 in pulmonary artery endothelial cells exposed to lipopolysaccharide

    PubMed Central

    Nanchal, Rahul; Audi, Said; Konduri, G. Ganesh; Medhora, Meetha

    2013-01-01

    Abstract Pulmonary or systemic infections and hypoxemic respiratory failure are among the leading causes of admission to intensive care units, and these conditions frequently exist in sequence or in tandem. Inflammatory responses to infections are reproduced by lipopolysaccharide (LPS) engaging Toll-like receptor 4 (TLR4). Apoptosis is a hallmark of lung injury in sepsis. This study was conducted to determine whether preexposure to LPS or hypoxia modulated the survival of pulmonary artery endothelial cells (PAECs). We also investigated the role TLR4 receptor expression plays in apoptosis due to these conditions. Bovine PAECs were cultured in hypoxic or normoxic environments and treated with LPS. TLR4 antagonist TAK-242 was used to probe the role played by TLR4 receptors in cell survival. Cell apoptosis and survival were measured by caspase 3 activity and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) incorporation. TLR4 expression and tumor necrosis factor α (TNF-α) production were also determined. LPS increased caspase 3 activity in a TAK-242-sensitive manner and decreased MTT incorporation. Apoptosis was decreased in PAECs preconditioned with hypoxia prior to LPS exposure. LPS increased TNF-α production, and hypoxic preconditioning blunted it. Hypoxic preconditioning reduced LPS-induced TLR4 messenger RNA and TLR4 protein. TAK-242 decreased to baseline the LPS-stimulated expression of TLR4 messenger RNA regardless of environmental conditions. In contrast, LPS followed by hypoxia substantially increased apoptosis and cell death. In conclusion, protection from LPS-stimulated PAEC apoptosis by hypoxic preconditioning is attributable in part to reduction in TLR4 expression. If these signaling pathways apply to septic patients, they may account for differing sensitivities of individuals to acute lung injury depending on oxygen tensions in PAECs in vivo. PMID:24618542

  1. Regulation of Toll-like receptor 2 interaction with Ecgp96 controls Escherichia coli K1 invasion of brain endothelial cells.

    PubMed

    Krishnan, Subramanian; Chen, Shuang; Turcatel, Gianluca; Arditi, Moshe; Prasadarao, Nemani V

    2013-01-01

    The interaction of outer membrane protein A (OmpA) with its receptor, Ecgp96 (a homologue of Hsp90β), is critical for the pathogenesis of Escherichia coli K1 meningitis. Since Hsp90 chaperones Toll-like receptors (TLRs), we examined the role of TLRs in E. coli K1 infection. Herein, we show that newborn TLR2(-/-) mice are resistant to E. coli K1 meningitis, while TLR4(-/-) mice succumb to infection sooner. In vitro, OmpA+ E. coli infection selectively upregulates Ecgp96 and TLR2 in human brain microvascular endothelial cells (HBMEC), whereas OmpA- E. coli upregulates TLR4 in these cells. Furthermore, infection with OmpA+ E. coli causes Ecgp96 and TLR2 translocate to the plasma membrane of HBMEC as a complex. Immunoprecipitation studies of the plasma membrane fractions from infected HBMEC reveal that the C termini of Ecgp96 and TLR2 are critical for OmpA+ E. coli invasion. Knockdown of TLR2 using siRNA results in inefficient membrane translocation of Ecgp96 and significantly reduces invasion. In addition, the interaction of Ecgp96 andTLR2 induces a bipartite signal, one from Ecgp96 through PKC-α while the other from TLR2 through MyD88, ERK1/2 and NF-κB. This bipartite signal ultimately culminates in the efficient production of NO, which in turn promotes E. coli K1 invasion of HBMEC. © 2012 Blackwell Publishing Ltd.

  2. Reduced hepatic injury in Toll-like receptor 4-deficient mice following D-galactosamine/lipopolysaccharide-induced fulminant hepatic failure.

    PubMed

    Ben Ari, Ziv; Avlas, Orna; Pappo, Orit; Zilbermints, Veacheslav; Cheporko, Yelena; Bachmetov, Larissa; Zemel, Romy; Shainberg, Asher; Sharon, Eran; Grief, Franklin; Hochhauser, Edith

    2012-01-01

    Liver transplantation is the only therapy of proven benefit in fulminant hepatic failure (FHF). Lipopolysaccharide (LPS), D-galactosamine (GalN)-induced FHF is a well established model of liver injury in mice. Toll-Like Receptor 4 (TLR4) has been identified as a receptor for LPS. The aim of this study was to investigate the role of TLR4 in FHF induced by D-GalN/LPS administration in mice. Wild type (WT) and TLR4 deficient (TLR4ko) mice were studied in vivo in a fulminant model induced by GalN/LPS. Hepatic TLR4 expression, serum liver enzymes, hepatic and serum TNF-α and interleukin-1β levels were determined. Apoptotic cells were identified by immunohistochemistry for caspase-3. Nuclear factor-kappaβ (NF-κ β) and phosphorylated c-Jun hepatic expression were studied using Western blot analysis. All WT mice died within 24 hours after administration of GalN/LPS while all TLR4ko mice survived. Serum liver enzymes, interleukin-1β, TNF-α level, TLR4 mRNA expression, hepatic injury and hepatocyte apoptosis all significantly decreased in TLR4ko mice compared with WT mice. A significant decrease in hepatic c-Jun and IκB signaling pathway was noted in TLR4ko mice compared with WT mice. In conclusion, following induction of FHF, the inflammatory response and the liver injury in TLR4ko mice was significantly attenuated through decreased hepatic c-Jun and NF-κB expression and thus decreased TNF-α level. Down-regulation of TLR4 expression plays a pivotal role in GalN/LPS induced FHF. These findings might have important implications for the use of the anti TLR4 protein signaling as a potential target for therapeutic intervention in FHF. Copyright © 2012 S. Karger AG, Basel.

  3. Disulfide high mobility group box-1 causes bladder pain through bladder Toll-like receptor 4.

    PubMed

    Ma, Fei; Kouzoukas, Dimitrios E; Meyer-Siegler, Katherine L; Westlund, Karin N; Hunt, David E; Vera, Pedro L

    2017-05-25

    Bladder pain is a prominent symptom in several urological conditions (e.g. infection, painful bladder syndrome/interstitial cystitis, cancer). Understanding the mechanism of bladder pain is important, particularly when the pain is not accompanied by bladder pathology. Stimulation of protease activated receptor 4 (PAR4) in the urothelium results in bladder pain through release of urothelial high mobility group box-1 (HMGB1). HGMB1 has two functionally active redox states (disulfide and all-thiol) and it is not known which form elicits bladder pain. Therefore, we investigated whether intravesical administration of specific HMGB1 redox forms caused abdominal mechanical hypersensitivity, micturition changes, and bladder inflammation in female C57BL/6 mice 24 hours post-administration. Moreover, we determined which of the specific HMGB1 receptors, Toll-like receptor 4 (TLR4) or receptor for advanced glycation end products (RAGE), mediate HMGB1-induced changes. Disulfide HMGB1 elicited abdominal mechanical hypersensitivity 24 hours after intravesical (5, 10, 20 μg/150 μl) instillation. In contrast, all-thiol HMGB1 did not produce abdominal mechanical hypersensitivity in any of the doses tested (1, 2, 5, 10, 20 μg/150 μl). Both HMGB1 redox forms caused micturition changes only at the highest dose tested (20 μg/150 μl) while eliciting mild bladder edema and reactive changes at all doses. We subsequently tested whether the effects of intravesical disulfide HMGB1 (10 μg/150 μl; a dose that did not produce inflammation) were prevented by systemic (i.p.) or local (intravesical) administration of either a TLR4 antagonist (TAK-242) or a RAGE antagonist (FPS-ZM1). Systemic administration of either TAK-242 (3 mg/kg) or FPS-ZM1 (10 mg/kg) prevented HMGB1 induced abdominal mechanical hypersensitivity while only intravesical TLR4 antagonist pretreatment (1.5 mg/ml; not RAGE) had this effect. The disulfide form of HMGB1 mediates bladder pain directly (not

  4. Interplay of Toll-Like Receptor 9, Myeloid Cells, and Deubiquitinase A20 in Periodontal Inflammation

    PubMed Central

    Crump, Katie E.; Oakley, Jennifer C.; Xia-Juan, Xia; Madu, Theandra C.; Devaki, Swathi; Mooney, Erin C.

    2016-01-01

    ABSTRACT Toll-like receptor 9 (TLR9)-deficient (TLR9−/−) mice are resistant to periodontitis, a disease characterized by a dysbiotic microbiota and deregulated immune response and resulting in tooth loss and various systemic conditions. However, the mechanisms and biological pathways by which TLR9 instigates periodontal inflammation are yet to be identified. In a ligature-induced model of periodontitis, we demonstrate that TLR9−/− mice exhibited significantly less alveolar bone loss than their wild-type (WT) counterparts. Consistent with the disease phenotype, gingival tissues showed significantly more inflammatory cell infiltration in the WT ligated but not in the TLR9−/− ligated mice compared to the unligated controls. The peritoneal infection model using Porphyromonas gingivalis, a keystone pathogen for periodontitis, revealed reduced neutrophils in TLR9−/− mice on day 1 postinfection compared to the levels in WT mice. Transcriptomics analyses showed increased expression of A20 (tumor necrosis factor alpha [TNF-α]-induced protein 3 [TNFAIP3]), an inhibitor of the NF-κB pathway and a negative regulator of TLR signaling, in ligated TLR9−/− mouse gingival tissues compared to its expression in the WT. Ex vivo, TLR9−/− bone marrow-derived macrophages produced more A20 than WT cells following P. gingivalis challenge. Clinically, A20 was modestly upregulated in human gingival tissue specimens from chronic periodontitis patients, further confirming the biological relevance of A20 in periodontal inflammation. We conclude that TLR9 modulates periodontal disease progression at both the cellular and molecular level and identify A20 as a novel downstream signaling molecule in the course of periodontal inflammation. Understanding the regulation of the TLR9 signaling pathway and the involvement of A20 as a limiting factor of inflammation will uncover alternative therapeutic targets to treat periodontitis and other chronic inflammatory diseases. PMID

  5. Cardiolipins Act as a Selective Barrier to Toll-Like Receptor 4 Activation in the Intestine

    PubMed Central

    Coats, Stephen R.; Hashim, Ahmed; Paramonov, Nikolay A.; Curtis, Michael A.

    2016-01-01

    ABSTRACT Intestinal homeostasis mechanisms must protect the host intestinal tissue from endogenous lipopolysaccharides (LPSs) produced by the intestinal microbiota. In this report, we demonstrate that murine intestinal fecal lipids effectively block Toll-like receptor 4 (TLR4) responses to naturally occurring Bacteroidetes sp. LPS. Cardiolipin (CL) represents a significant proportion of the total intestinal and fecal lipids and, furthermore, potently antagonizes TLR4 activation by reducing LPS binding at the lipopolysaccharide binding protein (LBP), CD14, and MD-2 steps of the TLR4 signaling pathway. It is further demonstrated that intestinal lipids and CL are less effective at neutralizing more potent Enterobacteriaceae-type LPS, which is enriched in feces obtained from mice with dextran sodium sulfate (DSS)-treated inflammatory bowel disease. The selective inhibition of naturally occurring LPS structures by intestinal lipids may represent a novel homeostasis mechanism that blocks LPS activation in response to symbiotic but not dysbiotic microbial communities. IMPORTANCE The guts of animals harbor a variety of Gram-negative bacteria associated with both states of intestinal health and states of disease. Environmental factors, such as dietary habits, can drive the microbial composition of the host animal's intestinal bacterial community toward a more pathogenic state. Both beneficial and harmful Gram-negative bacteria are capable of eliciting potentially damaging inflammatory responses from the host intestinal tissues via a lipopolysaccharide (LPS)-dependent pathway. Physical mucosal barriers and antibodies produced by the intestinal immune system protect against the undesired inflammatory effects of LPS, although it is unknown why some bacteria are more effective at overcoming the protective barriers than others. This report describes the discovery of a lipid-type protective barrier in the intestine that reduces the deleterious effects of LPSs from beneficial

  6. Evidence of activation of the Toll-like receptor-4 proinflammatory pathway in patients with schizophrenia

    PubMed Central

    García-Bueno, Borja; Gassó, Patricia; MacDowell, Karina S.; Callado, Luis F.; Mas, Sergi; Bernardo, Miguel; Lafuente, Amalia; Meana, J. Javier; Leza, Juan C.

    2016-01-01

    Background Alterations in the innate immune/inflammatory system may underlie the pathophysiology of schizophrenia, but we do not understand the mechanisms involved. The main agents of innate immunity are the Toll-like receptors (TLRs), which detect molecular patterns associated with damage and pathogens. The TLR first reported was TLR4, and it is still the most studied one. Methods We aimed to describe putative modifications to the TLR4 proinflammatory pathway using 2 different strategies in 2 cohorts of patients with schizophrenia and matched controls: 1) quantification of protein and mRNA expression in postmortem prefrontal cortex samples from 30 patients with schizophrenia and 30 controls, and 2) identification of single nucleotide polymorphisms associated with the risk of schizophrenia using whole blood samples from 214 patients with schizophrenia and 216 controls. Results We found evidence of alterations in the expression of the initial elements of the TLR4 signalling pathway (TLR4, Myeloid differentiation primary response gene 88 [MyD88] and nuclear factor-κ B [NF-κB]) in the PFC of patients with schizophrenia. These alterations seem to depend on the presence/absence of antipsychotic treatment at death. Moreover, a polymorphism within the MyD88 gene was significantly associated with schizophrenia risk. Limitations The use of 2 different approaches in 2 different cohorts, the lack of a complementary neuropsychiatric group, the possible confounding effects of antipsychotic treatment and suicide are the main limitations of our study. Conclusion The evidence from this dual approach suggests there is an altered innate immune response in patients with chronic schizophrenia in which the TLR4 proinflammatory pathway could be affected. Improved understanding of the stimuli and mechanisms responsible for this response could lead to improved schizophrenia treatment and better control of the side effects of current antipsychotics. PMID:27070349

  7. Toll-like receptor-4 signaling pathway in aorta aging and diseases: "its double nature".

    PubMed

    Balistreri, Carmela Rita; Ruvolo, Giovanni; Lio, Domenico; Madonna, Rosalinda

    2017-09-01

    Recent advances in the field of innate immunity have revealed a complex role of innate immune signaling pathways in both tissue homeostasis and disease. Among them, the Toll-like receptor 4 (TLR-4) pathways has been linked to various pathophysiological conditions, such as cardiovascular diseases (CVDs). This has been interrogated by developing multiple laboratory tools that have shown in animal models and clinical conditions, the involvement of the TLR-4 signaling pathway in the pathophysiology of different CVDs, such as atherosclerosis, ischemic heart disease, heart failure, ischemia-reperfusion injury and aorta aneurysm. Among these, aorta aneurysm, a very complex pathological condition with uncertain etiology and fatal complications (i.e. dissection and rupture), has been associated with the occurrence of high risk cardiovascular conditions, including thrombosis and embolism. In this review, we discuss the possible role of TLR-4 signaling pathway in the development of aorta aneurysm, considering the emerging evidence from ongoing investigations. Our message is that emphasizing the role of TLR-4 signaling pathway in aorta aneurysm may serve as a starting point for future studies, leading to a better understanding of the pathophysiological basis and perhaps the effective treatment of this difficult human disease. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. Higher Expression of Toll-like Receptors 3, 7, 8, and 9 in Pityriasis Rosea.

    PubMed

    El-Ela, Mostafa Abou; El-Komy, Mohamed; Hay, Rania Abdel; Hegazy, Rehab; Sharobim, Amin; Rashed, Laila; Amr, Khalda

    2017-03-01

    Pityriasis rosea (PR) is a common papulosquamous skin disease in which an infective agent may be implicated. Toll-like receptors (TLRs) play an important role in immune responses and in the pathophysiology of inflammatory skin diseases. Our aim was to determine the possible roles of TLRs 3, 7, 8, and 9 in the pathogenesis of PR. Twenty-four PR patients and 24 healthy individuals (as controls) were included in this case control study. All recruits were subjected to routine laboratory investigations. Biopsies were obtained from one active PR lesion and from healthy skin of controls for the detection of TLR 3, 7, 8, and 9 gene expression using real-time polymerase chain reaction. This study included 24 patients (8 females and 16 males) with active PR lesions, with a mean age of 28.62 years. Twenty four healthy age- and sex-matched individuals were included as controls (8 females and 16 males, with a mean age of 30.83 years). The results of the routine laboratory tests revealed no significant differences between both groups. Significantly elevated expression of all studied TLRs were detected in PR patients relative to healthy controls (p < .001). TLRs 3, 7, 8, and 9 might be involved in the pathogenesis of PR.

  9. Higher Expression of Toll-like Receptors 3, 7, 8, and 9 in Pityriasis Rosea

    PubMed Central

    El-Ela, Mostafa Abou; El-Komy, Mohamed; Hay, Rania Abdel; Hegazy, Rehab; Sharobim, Amin; Rashed, Laila; Amr, Khalda

    2017-01-01

    Background Pityriasis rosea (PR) is a common papulosquamous skin disease in which an infective agent may be implicated. Toll-like receptors (TLRs) play an important role in immune responses and in the pathophysiology of inflammatory skin diseases. Our aim was to determine the possible roles of TLRs 3, 7, 8, and 9 in the pathogenesis of PR. Methods Twenty-four PR patients and 24 healthy individuals (as controls) were included in this case control study. All recruits were subjected to routine laboratory investigations. Biopsies were obtained from one active PR lesion and from healthy skin of controls for the detection of TLR 3, 7, 8, and 9 gene expression using real-time polymerase chain reaction. Results This study included 24 patients (8 females and 16 males) with active PR lesions, with a mean age of 28.62 years. Twenty four healthy age- and sex-matched individuals were included as controls (8 females and 16 males, with a mean age of 30.83 years). The results of the routine laboratory tests revealed no significant differences between both groups. Significantly elevated expression of all studied TLRs were detected in PR patients relative to healthy controls (p < .001). Conclusions TLRs 3, 7, 8, and 9 might be involved in the pathogenesis of PR. PMID:28192646

  10. Toll like receptor 4: an important molecule in recognition and induction of appropriate immune responses against Chlamydia infection.

    PubMed

    Nosratababadi, Reza; Bagheri, Vahid; Zare-Bidaki, Mohammad; Hakimi, Hamid; Zainodini, Nahid; Kazemi Arababadi, Mohammad

    2017-04-01

    Chlamydia species are obligate intracellular pathogens causing different infectious diseases particularly asymptomatic genital infections and are also responsible for a wide range of complications. Previous studies showed that there are different immune responses to Chlamydia species and their infections are limited to some cases. Moreover, Chlamydia species are able to alter immune responses through modulating the expression of some immune system related molecules including cytokines. Toll like receptors (TLRs) belonge to pathogen recognition receptors (PRRs) and play vital roles in recognition of microbes and stimulation of appropriate immune responses. Therefore, it appears that TLRs may be considered as important sensors for recognition of Chlamydia and promotion of immune responses against these bacterial infections. Accordingly, TLR4 detects several microbial PAMPs such as bacterial lipopolysacharide (LPS) and subsequently activates transcription from pro-inflammatory cytokines in both MYD88 and TRIF pathways dependent manner. The purpose of this review is to provide the recent data about the status and major roles played by TLR4 in Chlamydia species recognition and promotion of immune responses against these infections and also the relationship between TLR4 activities and pathogenesis of Chlamydia infections. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Forkhead box-P3+ regulatory T cells and toll-like receptor 2 co-expression in oral squamous cell carcinoma.

    PubMed

    Hussaini, H M; Parachuru, V P B; Seymour, G J; Rich, A M

    2017-04-01

    The function of forkhead box-P3 (FoxP3) regulatory T cells (Treg) and toll-like receptor (TLR)2 protein in the oral cancer microenvironment is not fully understood, but evidence from other malignancies suggests it is likely they are involved with tumour development and progression. The aim of this study was to investigate the distribution of FoxP3 + cells, TLR2 + cells and double-labelled FoxP3 + TLR2 + immune cells in oral squamous cell carcinoma (OSCC), using immunohistochemistry (IHC) and immunofluorescence (IF). 25 archival cases of OSCC were immunostained with anti-FoxP3 and anti-TLR2 antibodies. Inflamed hyperplastic oral mucosal tissues were used as controls. The proportion of single-labelled, double-labelled and negative cells was determined. A higher frequency of double-labelled FoxP3 + TLR2 + Tregs was observed within the immune cells of OSCC compared to inflamed controls using IHC (p<0.05). Cell-to-cell contact between single-stained TLR2 + cells and FoxP3 + cells was noted. Double IF studies validated demonstration of co-expression of FoxP3 + /TLR2 + immune cells in OSCC. The presence of FoxP3 + TLR2 + cells within the OSCC microenvironment may represent a dendritic cell-dependent pathway capable of inhibiting Treg suppressive activity, potentially enhancing the anti-tumour response. Modulation of TLR2-Treg interactions should be further explored to determine if they have a role in the therapeutic management of OSCC. Copyright © 2017 Elsevier GmbH. All rights reserved.

  12. Lack of Toll-like receptor 2 results in higher mortality of bacterial meningitis by impaired host resistance.

    PubMed

    Böhland, Martin; Kress, Eugenia; Stope, Matthias B; Pufe, Thomas; Tauber, Simone C; Brandenburg, Lars-Ove

    2016-10-15

    Bacterial meningitis is - despite therapeutical progress during the last decades - still characterized by high mortality and severe permanent neurogical sequelae. The brain is protected from penetrating pathogens by both the blood-brain barrier and the innate immune system. Invading pathogens are recognized by so-called pattern recognition receptors including the Toll-like receptors (TLR) which are expressed by glial immune cells in the central nervous system. Among these, TLR2 is responsible for the detection of Gram-positive bacteria such as the meningitis-causing pathogen Streptococcus pneumoniae. Here, we used TLR2-deficient mice to investigate the effects on mortality, bacterial growth and inflammation in a mouse model of pneumococcal meningitis. Our results revealed a significantly increased mortality rate and higher bacterial burden in TLR2-deficient mice with pneumococcal meningitis. Furthermore, infected TLR2-deficient mice suffered from a significantly increased pro-inflammatory cytokine tumor necrosis factor-α (TNF-α) and Chemokine (C-C motif) ligand 2 (CCL2) or CCL3 chemokine expression and decreased expression of anti-inflammatory cytokines and antimicrobial peptides. In contrast, glial cell activation assessed by glial cell marker expression was comparable to wildtype mice. Taken together, the results suggest that TLR2 is essential for an efficient immune response against Streptococcus pneumoniae meningitis since lack of the receptor led to a worse outcome by higher mortality due to increased bacterial burden, weakened innate immune response and reduced expression of antimicrobial peptides. Copyright © 2016 Elsevier B.V. All rights reserved.

  13. Human TRAF3 adaptor molecule deficiency leads to impaired Toll-like receptor 3 response and susceptibility to herpes simplex encephalitis

    PubMed Central

    de Diego, Rebeca Pérez; Sancho-Shimizu, Vanessa; Lorenzo, Lazaro; Puel, Anne; Plancoulaine, Sabine; Picard, Capucine; Herman, Melina; Cardon, Annabelle; Durandy, Anne; Bustamante, Jacinta; Vallabhapurapu, Sivakumar; Bravo, Jerónimo; Warnatz, Klaus; Chaix, Yves; Cascarrigny, Françoise; Lebon, Pierre; Rozenberg, Flore; Karin, Michael; Tardieu, Marc; Al-Muhsen, Saleh; Jouanguy, Emmanuelle; Zhang, Shen-Ying; Abel, Laurent; Casanova, Jean-Laurent

    2010-01-01

    Tumor necrosis factor (TNF) receptor-associated factor 3 (TRAF3) functions downstream of multiple receptors that induce interferon-α (IFN-α), IFN–β and IFN-λ production, including Toll-like receptor 3 (TLR3), which is deficient in some patients with herpes simplex virus-1 encephalitis (HSE). Mice lacking TRAF3 die in the neonatal period, preventing direct investigation of the role of TRAF3 in immune responses and host defenses in vivo. Here we reported the autosomal dominant, human TRAF3 deficiency in a young adult with a history of HSE in childhood. The TRAF3 mutant allele was a loss-of-expression, loss-of-function, dominant-negative phenotype, and was associated with impaired, but not abolished TRAF3-dependent responses upon stimulation of both TNF receptors and receptors that induce IFN production. TRAF3 deficiency was associated with a clinical phenotype limited to HSE resulting from the impairment of TLR3-dependent induction of IFN. Thus, TLR3-mediated immunity against primary infection by HSV-1 in the central nervous system is critically dependent on TRAF3. Highlight sentence Autosomal dominant TRAF3 deficiency is a genetic etiology of herpes simplex encephalitis. Highlight sentence R118W TRAF3 allele is loss-of-function, loss-of-expression, and dominant-negative. Highlight sentence Human TRAF3 deficiency impairs the TLR3-dependent induction of anti-viral interferons. PMID:20832341

  14. Toll-like receptor 4-mediated cAMP production up-regulates B-cell activating factor expression in Raw264.7 macrophages.

    PubMed

    Moon, Eun-Yi; Lee, Yu-Sun; Choi, Wahn Soo; Lee, Mi-Hee

    2011-10-15

    B-cell activating factor (BAFF) plays a role in the generation and the maintenance of mature B cells. Lipopolysaccharide (LPS) increased BAFF expression through the activation of toll-like receptor 4 (TLR4)-dependent signal transduction. Here, we investigated the mechanism of action on mouse BAFF (mBAFF) expression by cAMP production in Raw264.7 mouse macrophages. mBAFF expression was increased by the treatment with a cAMP analogue, dibutyryl-cAMP which is the activator of protein kinase A (PKA), cAMP effector protein. PKA activation was measured by the phosphorylation of cAMP-response element binding protein (CREB) on serine 133 (S133). cAMP production and CREB (S133) phosphorylation were augmented by LPS-stimulation. While mBAFF promoter activity was enhanced by the co-transfection with pS6-RSV-CREB, it was reduced by siRNA-CREB. PKA inhibitor, H-89, reduced CREB (S133) phosphorylation and mBAFF expression in control and LPS-stimulated macrophages. Another principal cAMP effector protein is cAMP-responsive guanine nucleotide exchange factor (Epac), a Rap GDP exchange factor. Epac was activated by the treatment with 8-(4-chloro-phenylthio)-2'-O-methyladenosine-3',5'-cyclic monophosphate (CPT), Epac activator, as judged by the measurement of Rap1 activation. Basal level of mBAFF expression was increased by CPT treatment. LPS-stimulated mBAFF expression was also slightly enhanced by co-treatment with CPT. In addition, dibutyryl-cAMP and CPT enhanced mBAFF expression in bone marrow-derived macrophages (BMDM). With these data, it suggests that the activation of PKA and cAMP/Epac1/Rap1 pathways could be required for basal mBAFF expression, as well as being up-regulated in the TLR4-induced mBAFF expression. Crown Copyright © 2011. Published by Elsevier Inc. All rights reserved.

  15. The mAb against adipocyte fatty acid-binding protein 2E4 attenuates the inflammation in the mouse model of high-fat diet-induced obesity via toll-like receptor 4 pathway.

    PubMed

    Miao, Xiaoliang; Wang, Ying; Wang, Wang; Lv, Xiaobo; Wang, Min; Yin, Hongping

    2015-03-05

    Adipocyte fatty acid-binding protein (A-FABP) plays an important role in fatty acid-mediated processes and related metabolic and inflammatory responses. In this study, we prepared a novel monoclonal antibody against A-FABP, designated 2E4. Our data showed that 2E4 specifically binded to the recombinant A-FABP and native A-FABP of mice adipose tissue. Furthermore, we investigated the effect of 2E4 on metabolic and inflammatory responses in C57BL/6J obese mice fed on a high fat diet. 2E4 administration improved glucose response in high-fat-diet induced obese mice. The 2E4 treated groups exhibited lower free fatty acids, cholesterol, and triglycerides in a concentration-dependent manner. These changes were accompanied by down-regulated expression of pro-inflammatory cytokines in adipose tissue, including tumor necrosis factor α, monocyte chemotactic protein-1, and interleukin-6. Meanwhile, our data demonstrated that 2E4 significantly decreased the mRNA and protein levels of A-FABP in adipose tissue of mice. Further experiments showed that 2E4 notably suppressed the phosphorylation of IκBα and jun-N-terminal kinase through toll-like receptor 4 signaling pathway. Taken together, 2E4 is an effective monoclonal antibody against A-FABP, which attenuated the inflammatory responses induced in the high-fat-diet mice. These findings may provide scientific insight into the treatment of chronic low-grade inflammation in obesity. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  16. Retrovirus-Based Virus-Like Particle Immunogenicity and Its Modulation by Toll-Like Receptor Activation.

    PubMed

    Pitoiset, Fabien; Vazquez, Thomas; Levacher, Beatrice; Nehar-Belaid, Djamel; Dérian, Nicolas; Vigneron, James; Klatzmann, David; Bellier, Bertrand

    2017-11-01

    Retrovirus-derived virus-like particles (VLPs) are particularly interesting vaccine platforms, as they trigger efficient humoral and cellular immune responses and can be used to display heterologous antigens. In this study, we characterized the intrinsic immunogenicity of VLPs and investigated their possible adjuvantization by incorporation of Toll-like receptor (TLR) ligands. We designed a noncoding single-stranded RNA (ncRNA) that could be encapsidated by VLPs and induce TLR7/8 signaling. We found that VLPs efficiently induce in vitro dendritic cell activation, which can be improved by ncRNA encapsidation ( ncRNA VLPs). Transcriptome studies of dendritic cells harvested from the spleens of immunized mice identified antigen presentation and immune activation as the main gene expression signatures induced by VLPs, while TLR signaling and Th1 signatures characterize ncRNA VLPs. In vivo and compared with standard VLPs, ncRNA VLPs promoted Th1 responses and improved CD8 + T cell proliferation in a MyD88-dependent manner. In an HIV vaccine mouse model, HIV-pseudotyped ncRNA VLPs elicited stronger antigen-specific cellular and humoral responses than VLPs. Altogether, our findings provide molecular evidence for a strong vaccine potential of retrovirus-derived VLPs that can be further improved by harnessing TLR-mediated immune activation. IMPORTANCE We previously reported that DNA vaccines encoding antigens displayed in/on retroviral VLPs are more efficient than standard DNA vaccines at inducing cellular and humoral immune responses. We aimed to decipher the mechanisms and investigated the VLPs' immunogenicity independently of DNA vaccination. We show that VLPs have the ability to activate antigen-presenting cells directly, thus confirming their intrinsic immunostimulatory properties and their potential to be used as an antigenic platform. Notably, this immunogenicity can be further improved and/or oriented by the incorporation into VLPs of ncRNA, which provides further

  17. The complement system and toll-like receptors as integrated players in the pathophysiology of atherosclerosis.

    PubMed

    Hovland, Anders; Jonasson, Lena; Garred, Peter; Yndestad, Arne; Aukrust, Pål; Lappegård, Knut T; Espevik, Terje; Mollnes, Tom E

    2015-08-01

    Despite recent medical advances, atherosclerosis is a global burden accounting for numerous deaths and hospital admissions. Immune-mediated inflammation is a major component of the atherosclerotic process, but earlier research focus on adaptive immunity has gradually switched towards the role of innate immunity. The complement system and toll-like receptors (TLRs), and the crosstalk between them, may be of particular interest both with respect to pathogenesis and as therapeutic targets in atherosclerosis. Animal studies indicate that inhibition of C3a and C5a reduces atherosclerosis. In humans modified LDL-cholesterol activate complement and TLRs leading to downstream inflammation, and histopathological studies indicate that the innate immune system is present in atherosclerotic lesions. Moreover, clinical studies have demonstrated that both complement and TLRs are upregulated in atherosclerotic diseases, although interventional trials have this far been disappointing. However, based on recent research showing an intimate interplay between complement and TLRs we propose a model in which combined inhibition of both complement and TLRs may represent a potent anti-inflammatory therapeutic approach to reduce atherosclerosis. Copyright © 2015 The Authors. Published by Elsevier Ireland Ltd.. All rights reserved.

  18. Association between Toll-like receptor 4 Asp299Gly polymorphism and coronary heart disease susceptibility.

    PubMed

    Wu, B W; Zhu, J; Shi, H M; Jin, B; Wen, Z C

    2017-08-07

    Published data on the association between Toll-like receptor 4 (TLR4) Asp299Gly polymorphism and coronary heart disease (CHD) susceptibility are inconclusive. To derive a more precise estimation of the relationship, a meta-analysis was performed. English-language studies were identified by searching PubMed and Embase databases (up to November 2016). All epidemiological studies were regarding Caucasians because no TLR4 Asp/Gly and Gly/Gly genotypes have been detected in Asians. A total of 20 case-control studies involving 14,416 cases and 10,764 controls were included in the meta-analysis. Overall, no significant associations were found between TLR4 Asp299Gly polymorphism and CHD susceptibility in the dominant model (OR=0.89; 95%CI=0.74 to 1.06; P=0.20) pooled in the meta-analysis. In the subgroup analysis by CHD, non-significant associations were found in cases compared to controls. When stratified by control source, no significantly decreased risk was found in the additive model or dominant model. The present meta-analysis suggests that the TLR4 Asp299Gly polymorphism was not associated with decreased CHD risk in Caucasians.

  19. From The Cover: Induction of antiviral immunity requires Toll-like receptor signaling in both stromal and dendritic cell compartments

    NASA Astrophysics Data System (ADS)

    Sato, Ayuko; Iwasaki, Akiko

    2004-11-01

    Pattern recognition by Toll-like receptors (TLRs) is known to be important for the induction of dendritic cell (DC) maturation. DCs, in turn, are critically important in the initiation of T cell responses. However, most viruses do not infect DCs. This recognition system poses a biological problem in ensuring that most viral infections be detected by pattern recognition receptors. Furthermore, it is unknown what, if any, is the contribution of TLRs expressed by cells that are infected by a virus, versus TLRs expressed by DCs, in the initiation of antiviral adaptive immunity. Here we address these issues using a physiologically relevant model of mucosal infection with herpes simplex virus type 2. We demonstrate that innate immune recognition of viral infection occurs in two distinct stages, one at the level of the infected epithelial cells and the other at the level of the noninfected DCs. Importantly, both TLR-mediated recognition events are required for the induction of effector T cells. Our results demonstrate that virally infected tissues instruct DCs to initiate the appropriate class of effector T cell responses and reveal the critical importance of the stromal cells in detecting infectious agents through their own pattern recognition receptors. mucosal immunity | pattern recognition | viral infection

  20. Toll-Like Receptor 4 Deficiency Causes Reduced Exploratory Behavior in Mice Under Approach-Avoidance Conflict.

    PubMed

    Li, Chunlu; Yan, Yixiu; Cheng, Jingjing; Xiao, Gang; Gu, Jueqing; Zhang, Luqi; Yuan, Siyu; Wang, Junlu; Shen, Yi; Zhou, Yu-Dong

    2016-04-01

    Abnormal approach-avoidance behavior has been linked to deficits in the mesolimbic dopamine (DA) system of the brain. Recently, increasing evidence has indicated that toll-like receptor 4 (TLR4), an important pattern-recognition receptor in the innate immune system, can be directly activated by substances of abuse, resulting in an increase of the extracellular DA level in the nucleus accumbens. We thus hypothesized that TLR4-dependent signaling might regulate approach-avoidance behavior. To test this hypothesis, we compared the novelty-seeking and social interaction behaviors of TLR4-deficient (TLR4(-/-)) and wild-type (WT) mice in an approach-avoidance conflict situation in which the positive motivation to explore a novel object or interact with an unfamiliar mouse was counteracted by the negative motivation to hide in exposed, large spaces. We found that TLR4(-/-) mice exhibited reduced novelty-seeking and social interaction in the large open spaces. In less stressful test apparatuses similar in size to the mouse cage, however, TLR4(-/-) mice performed normally in both novelty-seeking and social interaction tests. The reduced exploratory behaviors under approach-avoidance conflict were not due to a high anxiety level or an enhanced fear response in the TLR4(-/-) mice, as these mice showed normal anxiety and fear responses in the open field and passive avoidance tests, respectively. Importantly, the novelty-seeking behavior in the large open field induced a higher level of c-Fos activation in the nucleus accumbens shell (NAcSh) in TLR4(-/-) mice than in WT mice. Partially inactivating the NAcSh via infusion of GABA receptor agonists restored the novelty-seeking behavior of TLR4(-/-) mice. These data suggested that TLR4 is crucial for positive motivational behavior under approach-avoidance conflict. TLR4-dependent activation of neurons in the NAcSh may contribute to this phenomenon.

  1. Toll-like receptor 9 mediates oral bacteria-induced IL-8 expression in gingival epithelial cells.

    PubMed

    Kim, Youngsook; Jo, Ah-ram; Jang, Da Hyun; Cho, Yong-Joon; Chun, Jongsik; Min, Byung-Moo; Choi, Youngnim

    2012-07-01

    Previously, we reported that various oral bacteria regulate interleukin (IL)-8 production differently in gingival epithelial cells. The aim of this study was to characterize the pattern recognition receptor(s) that mediate bacteria-induced IL-8 expression. Among ligands that mimic bacterial components, only a Toll-like receptor (TLR) 9 ligand enhanced IL-8 expression as determined by ELISA. Both normal and immortalized human gingival epithelial (HOK-16B) cells expressed TLR9 intracellularly and showed enhanced IL-8 expression in response to CpG-oligonucleotide. The ability of eight strains of four oral bacterial species to induce IL-8 expression in HOK-16B cells, and their invasion capacity were examined in the absence or presence of 2% human serum. The ability of purified bacterial DNA (bDNA) to induce IL-8 was also examined. Six out of eight strains increased IL-8 production in the absence of serum. Usage of an endosomal acidification blocker or a TLR9 antagonist inhibited the IL-8 induction by two potent strains. In the presence of serum, many strains lost the ability to induce IL-8 and presented substantially reduced invasion capacity. The IL-8-inducing ability of bacteria in the absence or presence of serum showed a strong positive correlation with their invasion index. The IL-8-inducing ability of bacteria in the absence of human serum was also correlated with the immunostimulatory activity of its bDNA. The observed immunostimulatory activity of the bDNA could not be linked to its CpG motif content. In conclusion, oral bacteria induce IL-8 in gingival epithelial cells through TLR9 and the IL-8-inducing ability depends on the invasive capacity and immunostimulating DNA.

  2. TRPV1 receptor-mediated expression of Toll-like receptors 2 and 4 following permanent middle cerebral artery occlusion in rats

    PubMed Central

    Hakimizadeh, Elham; Shamsizadeh, Ali; Roohbakhsh, Ali; Arababadi, Mohammad Kazemi; Hajizadeh, Mohammad Reza; Shariati, Mehdi; Fatemi, Iman; Moghadam-ahmadi, Amir; Bazmandegan, Gholamreza; Rezazadeh, Hossein; Allahtavakoli, Mohammad

    2017-01-01

    Objective(s): Stroke is known as a main cause of mortality and prolonged disability in adults. Both transient receptor potential V1 (TRPV1) channels and toll-like receptors (TLRs) are involved in mediating the inflammatory responses. In the present study, the effects of TRPV1 receptor activation and blockade on stroke outcome and gene expression of TLR2 and TLR4 were assessed following permanent middle cerebral artery occlusion in rats Materials and Methods: Eighty male Wistar rats were divided into four groups as follows: sham, vehicle, AMG9810 (TRPV1 antagonist) -treated and capsaicin (TRPV1 agonist) -treated. For Stroke induction, the middle cerebral artery was permanently occluded and then behavioral functions were evaluated 1, 3 and 7 days after stroke. Results: TRPV1 antagonism significantly reduced the infarct volume compared to the stroke group. Also, neurological deficits were decreased by AMG9810 seven days after cerebral ischemia. In the ledged beam-walking test, the slip ratio was enhanced following ischemia. AMG9810 decreased this index in stroke animals. However, capsaicin improved the ratio 3 and 7 days after cerebral ischemia. Compared to the sham group, the mRNA expression of TLR2 and TLR4 was significantly increased in the stroke rats. AMG9810 Administration significantly reduced the mRNA expression of TLR2 and TLR4. However, capsaicin did not significantly affect the gene expression of TLR2 and TLR4. Conclusion: Our results demonstrated that TRPV1 antagonism by AMG9810 attenuates behavioral function and mRNA expression of TLR2 and TLR4. Thus, it might be useful to shed light on future therapeutic strategies for the treatment of ischemic stroke. PMID:29085577

  3. Toll-like receptors in the pathogenesis of chemotherapy-induced gastrointestinal toxicity.

    PubMed

    Cario, Elke

    2016-06-01

    Intestinal mucositis represents a common complication and dose-limiting toxicity of cancer chemotherapy. So far chemotherapy-induced intestinal mucositis remains poorly treatable resulting in significant morbidity and reduced quality of life in cancer patients. This review discusses recent insights into the pathophysiology of chemotherapy-induced intestinal mucositis. Novel mechanisms linking gut microbiota, host innate immunity and anticancer drug metabolism are highlighted. Gut microbiota may affect xenobiotic metabolism by direct and indirect mechanisms, critically modulating gut toxicity of chemotherapy drugs. Composition and metabolic function of the gut microbiome as well as innate immune responses of the intestinal mucosa are severely altered during chemotherapy. Commensal-mediated innate immune signaling via Toll-like receptors (TLRs) ambiguously shapes chemotherapy-induced genotoxic damage in the gastrointestinal tract. TLR2 may accelerate host detoxification by activating the multidrug transporter ATP-binding cassette 1 (ABCB1)/MDR1 P-glycoprotein to efflux harmful drugs, thus controlling the severity of cancer therapy-induced mucosal damage in the gastrointestinal tract. In contrast, selective chemotherapy drugs may drive LPS hyperresponsiveness via TLR4, which exacerbates mucosal injury through aberrant cytokine storms. Broad-spectrum antibiotic treatment does not seem to represent a valid therapeutic option, as drastic reduction in global gut microbiota may enhance risk of gastrointestinal toxicity and reduce efficacy of some chemotherapy drugs, at least in murine models. Several variables (environment, metabolism, dysbiosis, infections and/or genetics) influence the outcome of mucosal TLR signaling during cancer treatment. Differences in innate immune responses also reflect chemotherapy drug-specific effects. Future studies must investigate in more detail whether manipulating the delicate balance between gut microbiota and host immune responses by

  4. Microbiome-Gut-Brain Axis and Toll-Like Receptors in Parkinson's Disease.

    PubMed

    Caputi, Valentina; Giron, Maria Cecilia

    2018-06-06

    Parkinson’s disease (PD) is a progressively debilitating neurodegenerative disease characterized by α-synucleinopathy, which involves all districts of the brain-gut axis, including the central, autonomic and enteric nervous systems. The highly bidirectional communication between the brain and the gut is markedly influenced by the microbiome through integrated immunological, neuroendocrine and neurological processes. The gut microbiota and its relevant metabolites interact with the host via a series of biochemical and functional inputs, thereby affecting host homeostasis and health. Indeed, a dysregulated microbiota-gut-brain axis in PD might lie at the basis of gastrointestinal dysfunctions which predominantly emerge many years prior to the diagnosis, corroborating the theory that the pathological process is spread from the gut to the brain. Toll-like receptors (TLRs) play a crucial role in innate immunity by recognizing conserved motifs primarily found in microorganisms and a dysregulation in their signaling may be implicated in α-synucleinopathy, such as PD. An overstimulation of the innate immune system due to gut dysbiosis and/or small intestinal bacterial overgrowth, together with higher intestinal barrier permeability, may provoke local and systemic inflammation as well as enteric neuroglial activation, ultimately triggering the development of alpha-synuclein pathology. In this review, we provide the current knowledge regarding the relationship between the microbiota-gut⁻brain axis and TLRs in PD. A better understanding of the dialogue sustained by the microbiota-gut-brain axis and innate immunity via TLR signaling should bring interesting insights in the pathophysiology of PD and provide novel dietary and/or therapeutic measures aimed at shaping the gut microbiota composition, improving the intestinal epithelial barrier function and balancing the innate immune response in PD patients, in order to influence the early phases of the

  5. Induction of Experimental Arthritis by Borrelial Lipoprotein and CpG Motifs: Are Toll-Like Receptors 2, 4, 9 or CD-14 Involved?

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Batsford, S.; Dunn, J.; Mihatsch, M.

    Bacterial lipoproteins and CpG-DNA are ligands for Toll-Like-Receptors (TLR) 2 and 9 respectively. Both classes of molecules were reported to induce experimental arthritis in rodents following direct intra-articular injection. Here we studied: (1) whether arthritis induction by Outer surface (Lipo)protein A (OspA) (B.burgdorferi) involved the TLR-2 as well as the TLR-4 or the CD-14 receptors in addition, and (2) re-examined the arthritogenic potential of CpG-DNA motifs in mice. Following intra-articular injection of the test substances [20 {micro}g recombinant, lipidated OspA; 1nM(6 {micro}g) to 10nM(60 {micro}g) synthetic CpG-DNA], inflammation was monitored by {sup 99}Tc scintigraphy (ratio left/right knee joint uptake >more » 1.1 indicates inflammation) and by histology. Lipoprotein OspA induced severe, acute arthritis in TLR-2{sup +/+} w.t. but not in TLR-2{sup -/-} mice (p<0.01). There were no significant differences in the severity of arthritis induced in TLR-4{sup +/+} w.t. and TLR-4{sup -/-} mutant mice, or between CD14{sup +/+} w.t. and CD14{sup -/-} mice. CpG-DNA (1or 10 nM) did not cause notable inflammation in C57BL/6 mice; {sup 99}Tc ratios were < 1.0 and histology showed only minimal changes. Induction of arthritis by the OspA lipoprotein of B.burgdorferi involves the TLR-2 receptor, no evidence for additional participation of TLR-4 or CD14 receptors was found. Intra-articular injection of CpG-DNA did not produce manifest joint injury in mice, at variance with previous reports.« less

  6. Site-specific incorporation of three toll-like receptor 2 targeting adjuvants into semisynthetic, molecularly defined nanoparticles: application to group a streptococcal vaccines.

    PubMed

    Moyle, Peter M; Dai, Wei; Zhang, Yingkai; Batzloff, Michael R; Good, Michael F; Toth, Istvan

    2014-05-21

    Subunit vaccines offer a means to produce safer, more defined vaccines compared to traditional whole microorganism approaches. Subunit antigens, however, exhibit weak immunity, which is normally overcome through coadministration with adjuvants. Enhanced vaccine properties (e.g., improved potency) can be obtained by linking antigen and adjuvant, as observed for synthetic peptide antigens and Toll-like receptor 2 (TLR2) ligands. As few protective peptide antigens have been reported, compared to protein antigens, we sought to extend the utility of this approach to recombinant proteins, while ensuring that conjugation reactions yielded a single, molecularly defined product. Herein we describe the development and optimization of techniques that enable the efficient, site-specific attachment of three synthetic TLR2 ligands (lipid core peptide (LCP), Pam2Cys, and Pam3Cys) onto engineered protein antigens, permitting the selection of optimal TLR2 agonists during the vaccine development process. Using this approach, broadly protective (J14) and population targeted (seven M protein N-terminal antigens) multiantigenic vaccines against group A streptococcus (GAS; Streptococcus pyogenes) were produced and observed to self-assemble in PBS to yield nanoparticules (69, 101, and 123 nm, respectively). All nanoparticle formulations exhibited self-adjuvanting properties, with rapid, persistent, antigen-specific IgG antibody responses elicited toward each antigen in subcutaneously immunized C57BL/6J mice. These antibodies were demonstrated to strongly bind to the cell surface of five GAS serotypes that are not represented by vaccine M protein N-terminal antigens, are among the top 20 circulating strains in developed countries, and are associated with clinical disease, suggesting that these vaccines may elicit broadly protective immune responses.

  7. Toll-Like Receptor Induced Pro-Interleukin-1β and Interleukin-6 in Monocytes Are Lower in Healthy Infants Compared to Adults

    PubMed Central

    Libraty, Daniel H.; Zhang, Lei; Woda, Marcia; Acosta, Luz P.; Obcena, AnaMae; Brion, Job D.; Capeding, Rosario Z.

    2013-01-01

    Infants have long been known to have higher infectious diseases morbidity and mortality and suboptimal vaccination responses compared to older children and adults. A variety of differences in innate and adaptive immune responses have been described between these two groups. We compared Toll-like receptor (TLR)-induced production of pro-interleukin (IL)-1β, IL-6, and tumor necrosis factor (TNF)-α between 2-month-old infants and adults. TLR 7/8-induced production of pro-IL-1β and IL-6 in monocytes was lower in 2-month-old infants compared to adults. There was no difference in TLR 7/8-induced production of TNF-α. Lower TLR-induced production of pro-IL-1β and IL-6 in innate immune cells during early infancy likely contributes to suboptimal vaccine responses and infectious diseases susceptibility. PMID:24205068

  8. Toll-like receptor induced pro-interleukin-1β and interleukin-6 in monocytes are lower in healthy infants compared to adults.

    PubMed

    Libraty, Daniel H; Zhang, Lei; Woda, Marcia; Acosta, Luz P; Obcena, Anamae; Brion, Job D; Capeding, Rosario Z

    2013-01-01

    Infants have long been known to have higher infectious diseases morbidity and mortality and suboptimal vaccination responses compared to older children and adults. A variety of differences in innate and adaptive immune responses have been described between these two groups. We compared Toll-like receptor (TLR)-induced production of pro-interleukin (IL)-1β, IL-6, and tumor necrosis factor (TNF)-α between 2-month-old infants and adults. TLR 7/8-induced production of pro-IL-1β and IL-6 in monocytes was lower in 2-month-old infants compared to adults. There was no difference in TLR 7/8-induced production of TNF-α. Lower TLR-induced production of pro-IL-1β and IL-6 in innate immune cells during early infancy likely contributes to suboptimal vaccine responses and infectious diseases susceptibility.

  9. TrkA and TrkC neurotrophin receptor-like proteins in the lizard gut.

    PubMed

    Lucini, C; de Girolamo, P; Lamanna, C; Botte, V; Vega, J A; Castaldo, L

    2001-03-01

    The tyrosine kinase proteins (Trk), encoded by the trk family of proto-oncogenes, mediate, in mammals, the action of neurotrophins, a family of growth factors acting on the development and maintenance of the nervous system. Neurotrophins and their specific receptors, TrkA, TrkB and TrkC, seem to be phylogenetically well preserved but, in reptiles, data regarding the occurrence of Trk-like proteins are very scarce, especially in non-nervous organs. Western blot analysis demonstrated that the lizard gut contains TrkA- and TrkC-like, but not TrkB-like, proteins. Consistently, TrkA- and TrkC-like immunoreactivity were both observed in neurons of the anterior intestine, whereas endocrine cells of the stomach and anterior intestine only displayed TrkA-like immunoreactivity. These results demonstrate for the first time the occurrence of Trk-like proteins in non-neuronal tissues of reptilians and provide further evidence for the evolutionary preservation of the molecular mass and cell distribution of Trk neurotrophin receptor-like proteins in the gut of vertebrates.

  10. Sonic hedgehog-Dependent Induction of MicroRNA 31 and MicroRNA 150 Regulates Mycobacterium bovis BCG-Driven Toll-Like Receptor 2 Signaling

    PubMed Central

    Ghorpade, Devram Sampat; Holla, Sahana; Kaveri, Srini V.; Bayry, Jagadeesh; Patil, Shripad A.

    2013-01-01

    Hedgehog (HH) signaling is a significant regulator of cell fate decisions during embryogenesis, development, and perpetuation of various disease conditions. Testing whether pathogen-specific HH signaling promotes unique innate recognition of intracellular bacteria, we demonstrate that among diverse Gram-positive or Gram-negative microbes, Mycobacterium bovis BCG, a vaccine strain, elicits a robust activation of Sonic HH (SHH) signaling in macrophages. Interestingly, sustained tumor necrosis factor alpha (TNF-α) secretion by macrophages was essential for robust SHH activation, as TNF-α−/− macrophages exhibited compromised ability to activate SHH signaling. Neutralization of TNF-α or blockade of TNF-α receptor signaling significantly reduced the infection-induced SHH signaling activation both in vitro and in vivo. Intriguingly, activated SHH signaling downregulated M. bovis BCG-mediated Toll-like receptor 2 (TLR2) signaling events to regulate a battery of genes associated with divergent functions of M1/M2 macrophages. Genome-wide expression profiling as well as conventional gain-of-function or loss-of-function analysis showed that SHH signaling-responsive microRNA 31 (miR-31) and miR-150 target MyD88, an adaptor protein of TLR2 signaling, thus leading to suppression of TLR2 responses. SHH signaling signatures could be detected in vivo in tuberculosis patients and M. bovis BCG-challenged mice. Collectively, these investigations identify SHH signaling to be what we believe is one of the significant regulators of host-pathogen interactions. PMID:23166298

  11. Adding exercise to rosuvastatin treatment: influence on C-reactive protein, monocyte toll-like receptor 4 expression, and inflammatory monocyte (CD14+CD16+) population.

    PubMed

    Coen, Paul M; Flynn, Michael G; Markofski, Melissa M; Pence, Brandt D; Hannemann, Robert E

    2010-12-01

    Statin treatment and exercise training can reduce markers of inflammation when administered separately. The purpose of this study was to determine the effect of rosuvastatin treatment and the addition of exercise training on circulating markers of inflammation including C-reactive protein (CRP), monocyte toll-like receptor 4 (TLR4) expression, and CD14+CD16+ monocyte population size. Thirty-three hypercholesterolemic and physically inactive subjects were randomly assigned to rosuvastatin (R) or rosuvastatin/exercise (RE) groups. A third group of physically active hypercholesterolemic subjects served as a control (AC). The R and RE groups received rosuvastatin treatment (10 mg/d) for 20 weeks. From week 10 to week 20, the RE group also participated in an exercise training program (3d/wk). Measurements were made at baseline (Pre), week 10 (Mid), and week 20 (Post), and included TLR4 expression on CD14+ monocytes and CD14+CD16+ monocyte population size as determined by 3-color flow cytometry. Serum CRP was quantified by enzyme-linked immunosorbent assay. TLR4 expression on CD14+ monocytes was higher in the R group at week 20. When treatment groups (R and RE) were combined, serum CRP was lower across time. Furthermore, serum CRP and inflammatory monocyte population size were lower in the RE group compared with the R group at the Post time point. When all groups (R, RE, and AC) were combined, TLR4 expression was greater on inflammatory monocytes (CD14+CD16+) compared with classic monocytes (CD14+CD16⁻) at all time points. In conclusion, rosuvastatin may influence monocyte inflammatory response by increasing TLR4 expression on circulating monocytes. The addition of exercise training to rosuvastatin treatment further lowered CRP and reduced the size of the inflammatory monocyte population, suggesting an additive anti-inflammatory effect of exercise. Copyright © 2010 Elsevier Inc. All rights reserved.

  12. Histone deacetylase 7 promotes Toll-like receptor 4-dependent proinflammatory gene expression in macrophages.

    PubMed

    Shakespear, Melanie R; Hohenhaus, Daniel M; Kelly, Greg M; Kamal, Nabilah A; Gupta, Praveer; Labzin, Larisa I; Schroder, Kate; Garceau, Valerie; Barbero, Sheila; Iyer, Abishek; Hume, David A; Reid, Robert C; Irvine, Katharine M; Fairlie, David P; Sweet, Matthew J

    2013-08-30

    Broad-spectrum inhibitors of histone deacetylases (HDACs) constrain Toll-like receptor (TLR)-inducible production of key proinflammatory mediators. Here we investigated HDAC-dependent inflammatory responses in mouse macrophages. Of the classical Hdacs, Hdac7 was expressed at elevated levels in inflammatory macrophages (thioglycollate-elicited peritoneal macrophages) as compared with bone marrow-derived macrophages and the RAW264 cell line. Overexpression of a specific, alternatively spliced isoform of Hdac7 lacking the N-terminal 22 amino acids (Hdac7-u), but not the Refseq Hdac7 (Hdac7-s), promoted LPS-inducible expression of Hdac-dependent genes (Edn1, Il-12p40, and Il-6) in RAW264 cells. A novel class IIa-selective HDAC inhibitor reduced recombinant human HDAC7 enzyme activity as well as TLR-induced production of inflammatory mediators in thioglycollate-elicited peritoneal macrophages. Both LPS and Hdac7-u up-regulated the activity of the Edn1 promoter in an HDAC-dependent fashion in RAW264 cells. A hypoxia-inducible factor (HIF) 1 binding site in this promoter was required for HDAC-dependent TLR-inducible promoter activity and for Hdac7- and HIF-1α-mediated trans-activation. Coimmunoprecipitation assays showed that both Hdac7-u and Hdac7-s interacted with HIF-1α, whereas only Hdac7-s interacted with the transcriptional repressor CtBP1. Thus, Hdac7-u positively regulates HIF-1α-dependent TLR signaling in macrophages, whereas an interaction with CtBP1 likely prevents Hdac7-s from exerting this effect. Hdac7 may represent a potential inflammatory disease target.

  13. Histone Deacetylase 7 Promotes Toll-like Receptor 4-dependent Proinflammatory Gene Expression in Macrophages*

    PubMed Central

    Shakespear, Melanie R.; Hohenhaus, Daniel M.; Kelly, Greg M.; Kamal, Nabilah A.; Gupta, Praveer; Labzin, Larisa I.; Schroder, Kate; Garceau, Valerie; Barbero, Sheila; Iyer, Abishek; Hume, David A.; Reid, Robert C.; Irvine, Katharine M.; Fairlie, David P.; Sweet, Matthew J.

    2013-01-01

    Broad-spectrum inhibitors of histone deacetylases (HDACs) constrain Toll-like receptor (TLR)-inducible production of key proinflammatory mediators. Here we investigated HDAC-dependent inflammatory responses in mouse macrophages. Of the classical Hdacs, Hdac7 was expressed at elevated levels in inflammatory macrophages (thioglycollate-elicited peritoneal macrophages) as compared with bone marrow-derived macrophages and the RAW264 cell line. Overexpression of a specific, alternatively spliced isoform of Hdac7 lacking the N-terminal 22 amino acids (Hdac7-u), but not the Refseq Hdac7 (Hdac7-s), promoted LPS-inducible expression of Hdac-dependent genes (Edn1, Il-12p40, and Il-6) in RAW264 cells. A novel class IIa-selective HDAC inhibitor reduced recombinant human HDAC7 enzyme activity as well as TLR-induced production of inflammatory mediators in thioglycollate-elicited peritoneal macrophages. Both LPS and Hdac7-u up-regulated the activity of the Edn1 promoter in an HDAC-dependent fashion in RAW264 cells. A hypoxia-inducible factor (HIF) 1 binding site in this promoter was required for HDAC-dependent TLR-inducible promoter activity and for Hdac7- and HIF-1α-mediated trans-activation. Coimmunoprecipitation assays showed that both Hdac7-u and Hdac7-s interacted with HIF-1α, whereas only Hdac7-s interacted with the transcriptional repressor CtBP1. Thus, Hdac7-u positively regulates HIF-1α-dependent TLR signaling in macrophages, whereas an interaction with CtBP1 likely prevents Hdac7-s from exerting this effect. Hdac7 may represent a potential inflammatory disease target. PMID:23853092

  14. Reconstruction of Toll-like receptor 9-mediated responses in HEK-Blue hTLR9 cells by transfection of human macrophage scavenger receptor 1 gene.

    PubMed

    Ohtsuki, Shozo; Takahashi, Yuki; Inoue, Takao; Takakura, Yoshinobu; Nishikawa, Makiya

    2017-10-20

    We used human Toll-like receptor 9 (hTLR9)-expressing HEK-Blue hTLR9 cells, which release secreted embryonic alkaline phosphatase (SEAP) upon response to CpG DNA, to evaluate the immunological properties of nucleic acid drug candidates. Our preliminary studies showed that phosphodiester CpG DNA hardly induced any SEAP secretion in HEK-Blue hTLR9 cells. In the current study, therefore, we developed HEK-Blue hTLR9 cells transduced with human macrophage scavenger receptor-1 (hMSR1), a cell-surface DNA receptor, and determined whether HEK-Blue hTLR9/hMSR1 cells respond to phosphorothioate (PS) CpG DNA and phosphodiester (PO) CpG DNA. We selected PS CpG2006, a single-stranded PO CpG DNA (ssCpG), and a tetrapod-like structured DNA (tetrapodna) containing ssCpG (tetraCpG) as model TLR9 ligands. Alexa Fluor 488-labeled ligands were used for flow cytometry. Unlike the mock-transfected HEK-Blue hTLR9 cells, the HEK-Blue hTLR9/hMSR1 cells efficiently took up all three CpG DNAs. SEAP release was almost proportional to the uptake. Treatment of HEK-Blue hTLR9/hMSR1 cells with an anti-hMSR1 antibody significantly reduced the uptake of ssCpG and tetraCpG. Collectively, reconstruction of TLR9-mediated responses to CpG DNA in HEK-Blue hTLR9 cells can be used to evaluate the toxicity of nucleic acid drug candidates with diverse physicochemical properties.

  15. Signatures of selection acting on the innate immunity gene Toll-like receptor 2 (TLR2) during the evolutionary history of rodents.

    PubMed

    Tschirren, B; Råberg, L; Westerdahl, H

    2011-06-01

    Patterns of selection acting on immune defence genes have recently been the focus of considerable interest. Yet, when it comes to vertebrates, studies have mainly focused on the acquired branch of the immune system. Consequently, the direction and strength of selection acting on genes of the vertebrate innate immune defence remain poorly understood. Here, we present a molecular analysis of selection on an important receptor of the innate immune system of vertebrates, the Toll-like receptor 2 (TLR2), across 17 rodent species. Although purifying selection was the prevalent evolutionary force acting on most parts of the rodent TLR2, we found that codons in close proximity to pathogen-binding and TLR2-TLR1 heterodimerization sites have been subject to positive selection. This indicates that parasite-mediated selection is not restricted to acquired immune system genes like the major histocompatibility complex, but also affects innate defence genes. To obtain a comprehensive understanding of evolutionary processes in host-parasite systems, both innate and acquired immunity thus need to be considered. © 2011 The Authors. Journal of Evolutionary Biology © 2011 European Society For Evolutionary Biology.

  16. Stable Toll-Like Receptor 10 Knockdown in THP-1 Cells Reduces TLR-Ligand-Induced Proinflammatory Cytokine Expression.

    PubMed

    Le, Hai Van; Kim, Jae Young

    2016-06-01

    Toll-like receptor 10 (TLR10) is the only orphan receptor whose natural ligand and function are unknown among the 10 human TLRs. In this study, to test whether TLR10 recognizes some known TLR ligands, we established a stable TLR10 knockdown human monocytic cell line THP-1 using TLR10 short hairpin RNA lentiviral particle and puromycin selection. Among 60 TLR10 knockdown clones that were derived from each single transduced cell, six clones were randomly selected, and then one of those clones, named E7, was chosen for the functional study. E7 exhibited approximately 50% inhibition of TLR10 mRNA and protein expression. Of all the TLRs, only the expression of TLR10 changed significantly in this cell line. Additionally, phorbol 12-myristate 13-acetate-induced macrophage differentiation of TLR10 knockdown cells was not affected in the knockdown cells. When exposed to TLR ligands, such as synthetic diacylated lipoprotein (FSL-1), lipopolysaccharide (LPS), and flagellin, significant induction of proinflammatory cytokine gene expression including Interleukin-8 (IL-8), Interleukin-1 beta (IL-1β), Tumor necrosis factor-alpha (TNF-α) and Chemokine (C-C Motif) Ligand 20 (CCL20) expression, was found in the control THP-1 cells, whereas the TLR10 knockdown cells exhibited a significant reduction in the expression of IL-8, IL-1β, and CCL20. TNF-α was the only cytokine for which the expression did not decrease in the TLR10 knockdown cells from that measured in the control cells. Analysis of putative binding sites for transcription factors using a binding-site-prediction program revealed that the TNF-α promoter does not have putative binding sites for AP-1 or c-Jun, comprising a major transcription factor along with NF-κB for TLR signaling. Our results suggest that TLR10 is involved in the recognition of FSL-1, LPS, and flagellin and TLR-ligand-induced expression of TNF-α does not depend on TLR10.

  17. Toll-like receptors in the inflammatory response during open and laparoscopic colectomy for colorectal cancer.

    PubMed

    Tsimogiannis, Konstantinos E; Tellis, Constantinos C; Tselepis, Alexandros D; Pappas-Gogos, George K; Tsimoyiannis, Evangelos C; Basdanis, George

    2012-02-01

    Surgical interventions activate a cascade of reactions that result in an aseptic inflammatory reaction. This inflammatory response initiates the organism's innate immunity. Laparoscopic surgery reduces the trauma, and patients benefit from diminished surgical trauma and maintained immune function. Cytokine levels and C-reactive protein (CRP) are related to the magnitude of surgical trauma and surgical stress. Toll-like receptors (TLRs) 2 and 4 are the first sensor-recognition receptors of the invading pathogens for the innate immune response. This study aimed to compare the inflammatory response and then the stress response during laparoscopic and open colectomy for cancer by calculating TLR-2 and TLR-4 as the first sensor-recognition receptors together with interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), and high-sensitivity CRP (hsCRP). A total 40 patients with colorectal cancer were randomized in two groups: group A (open colectomy, n = 20) and group B (laparoscopic colectomy, n = 20). An epidural catheter was placed in all patients 1 h preoperatively. Rupivocaine was administered perioperatively and 48 h postoperatively. Blood samples were taken for calculation of IL-6, TNF-α, hsCRP, TLR-2, and TLR-4 preoperatively and 5 min after deflation of pneumoperitoneum (group B) or 5 min after division of the colon (group A), then 6 and 24 h postoperatively. The mean operative time was 115 for group A and 142 min for group B. The mean blood loss was respectively 240 and 105 ml (P < 0.001), and the mean hospital stay was respectively 8 and 5 days (P < 0.05). The IL-6 level was significant higher in group A than in group B at 6 and 24 h postoperatively (P < 0.0001), and the hsCRP level was significant higher in group A than in group B at 24 h postoperatively (P < 0.001). The TNF-α values did not differ between the two groups. The TLR-2 level was significantly higher in group A than in group B at 5 min (P = 0.013) and 24 h (P = 0.007) postoperatively. The TLR-4

  18. Toll-like receptor 2 is upregulated by hog confinement dust in an IL-6 dependent manner in the airway epithelium

    PubMed Central

    Bailey, KL; Poole, JA; Mathisen, TL; Wyatt, TA; Von Essen, SG; Romberger, DJ

    2009-01-01

    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 hours 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. In order 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. PMID:18359883

  19. Diversity in the Toll-Like Receptor Genes of the African Penguin (Spheniscus demersus).

    PubMed

    Dalton, Desiré Lee; Vermaak, Elaine; Roelofse, Marli; Kotze, Antoinette

    2016-01-01

    The African penguin, Spheniscus demersus, is listed as Endangered by the IUCN Red List of Threatened Species due to the drastic reduction in population numbers over the last 20 years. To date, the only studies on immunogenetic variation in penguins have been conducted on the major histocompatibility complex (MHC) genes. It was shown in humans that up to half of the genetic variability in immune responses to pathogens are located in non-MHC genes. Toll-like receptors (TLRs) are now increasingly being studied in a variety of taxa as a broader approach to determine functional genetic diversity. In this study, we confirm low genetic diversity in the innate immune region of African penguins similar to that observed in New Zealand robin that has undergone several severe population bottlenecks. Single nucleotide polymorphism (SNP) diversity across TLRs varied between ex situ and in situ penguins with the number of non-synonymous alterations in ex situ populations (n = 14) being reduced in comparison to in situ populations (n = 16). Maintaining adaptive diversity is of vital importance in the assurance populations as these animals may potentially be used in the future for re-introductions. Therefore, this study provides essential data on immune gene diversity in penguins and will assist in providing an additional monitoring tool for African penguin in the wild, as well as to monitor diversity in ex situ populations and to ensure that diversity found in the in situ populations are captured in the assurance populations.

  20. Insulin receptor sensitizer, dicholine succinate, prevents both Toll-like receptor 4 (TLR4) upregulation and affective changes induced by a high-cholesterol diet in mice.

    PubMed

    Strekalova, Tatyana; Costa-Nunes, João P; Veniaminova, Ekaterina; Kubatiev, Aslan; Lesch, Klaus-Peter; Chekhonin, Vladimir P; Evans, Matthew C; Steinbusch, Harry W M

    2016-05-15

    High cholesterol intake in mice induces hepatic lipid dystrophy and inflammation, signs of non-alcoholic fatty liver disease (NAFLD), depressive- and anxiety-like behaviors, and the up-regulation of brain and liver Toll-like receptor 4 (Tlr4). Here, we investigated whether dicholine succinate (DS), an insulin receptor sensitizer and mitochondrial complex II substrate would interact with these effects. C57BL/6J mice were given a 0.2%-cholesterol diet for 3 weeks, alone or along with oral DS administration, or a control feed. Outcomes included behavioral measures of anxiety/depression, and Tlr4 and peroxisome-proliferator-activated-receptor-gamma coactivator-1b (PPARGC1b) expression. 50mg/kg DS treatment for 3 weeks partially ameliorated the cholesterol-induced anxiety- and depressive-like changes. Mice were next treated at the higher dose (180mg/kg), either for the 3-week period of dietary intervention, or for the last two weeks. Three-week DS administration normalized behaviors in the forced swim and O-maze tests and abolished the Tlr4 up-regulation in the brain and liver. The delayed, 2-week DS treatment had similar effects on Tlr4 expression and largely rescued the above-mentioned behaviors. Suppression of PPARGC1b, a master regulator of mitochondrial biogenesis, by the high cholesterol diet, was prevented with the 3-week administration, and markedly diminished by the a 2-week administration of DS. None of treatments prevented hepatic dystrophy and triglyceride accumulation. Other conditions have to be tested to define possible limitations of reported effects of DS. DS treatment did not alter the patho-morphological substrates of NAFLD syndrome in mice, but ameliorated its molecular and behavioral consequences, likely by activating mitochondrial functions and anti-inflammatory mechanisms. Copyright © 2016 Elsevier B.V. All rights reserved.

  1. Pu-erh Tea Reduces Nitric Oxide Levels in Rats by Inhibiting Inducible Nitric Oxide Synthase Expression through Toll-Like Receptor 4

    PubMed Central

    Xu, Yang; Wang, Guan; Li, Chunjie; Zhang, Min; Zhao, Hang; Sheng, Jun; Shi, Wei

    2012-01-01

    Pu-erh tea undergoes a unique fermentation process and contains theabrownins, polysaccharides and caffeine; although it is unclear about which component is associated with the down regulation of nitric oxide levels or how this process is mediated. To address this question we examined the effects of pu-erh tea on nitric oxide synthase (NOS) genes. Cohorts of rats were separately given four-week treatments of water as control, pu-erh tea, or the tea components: theabrownins, caffeine or polysaccharides. Five experimental groups were injected with lipopolysaccharides (LPS) to induce nitric oxide (NO) production, while the corresponding five control groups were injected with saline as a negative control. The serum and liver NO concentrations were examined and the NOS expression of both mRNA and protein was measured in liver. The results showed that the rats which were fed pu-erh tea or polysaccharides had lower levels of NO which corresponded with the down-regulation of inducible nitric oxide synthase (iNOS) expression. We further demonstrate that this effect is mediated through reduction of Toll-like receptor 4 (TLR4) signaling. Thus we find that the polysaccharide components in pu-erh tea reduce NO levels in an animal model by inhibiting the iNOS expression via signaling through TLR4. PMID:22837686

  2. Bacterial lipopeptide triggers massive albuminuria in murine lupus nephritis by activating Toll-like receptor 2 at the glomerular filtration barrier

    PubMed Central

    Pawar, Rahul D; Castrezana-Lopez, Liliana; Allam, Ramanjaneyulu; Kulkarni, Onkar P; Segerer, Stephan; Radomska, Ewa; Meyer, Tobias N; Schwesinger, Catherine-Meyer; Akis, Nese; Gröne, Hermann-Josef; Anders, Hans-Joachim

    2009-01-01

    What are the molecular mechanisms of bacterial infections triggering or modulating lupus nephritis? In nephritic MRLlpr/lpr mice, transient exposure to bacterial cell wall components such as lipopeptide or lipopolysaccharide (LPS) increased splenomegaly, the production of DNA autoantibodies, and serum interleukin (IL)-6, IL-12 and tumour necrosis factor (TNF) levels, and aggravated lupus nephritis. Remarkably, bacterial lipopeptide induced massive albuminuria in nephritic but not in non-nephritic mice. This was associated with down-regulation of renal nephrin mRNA and redistribution from its normal localization at foot processes to the perinuclear podocyte area in nephritic MRLlpr/lpr mice. Bacterial lipopeptide activates Toll-like receptor 2 (TLR2), which we found to be expressed on cultured podocytes and glomerular endothelial cells. TNF and interferon (IFN)-γ induced TLR2 mRNA and receptor expression in both cell types. Albumin permeability was significantly increased in cultured podocytes and glomerular endothelial cells upon stimulation by bacterial lipopeptide. LPS also induced moderate albuminuria. In summary, bacterial lipopeptide and LPS can aggravate glomerulonephritis but only lipopeptide potently induces severe albuminuria in MRLlpr/lpr mice. PMID:19175801

  3. Direct binding of Toll-like receptor 4 to ionotropic glutamate receptor N-methyl-D-aspartate subunit 1 induced by lipopolysaccharide in microglial cells N9 and EOC 20.

    PubMed

    Cui, Jie; Yu, Siyuan; Li, Yihui; Li, Pan; Liu, Feng

    2018-03-01

    Microglia, the primary immune cells in the brain, are the predominant cells regulating inflammation-mediated neuronal damage. In response to immunological challenges, such as lipopolysaccharide (LPS), microglia are activated and the inflammatory process is subsequently initiated. The aim of the present study was to determine whether LPS induces interactions between the Toll-like receptor 4 (TLR4) and the ionotropic glutamate receptor N-methyl-D‑aspartate subunit 1 (GluN1) in N9 and EOC 20 microglial cells. Immunocytochemistry demonstrated co-localization of TLR4 and GluN1 in response to LPS, and the direct binding of TLR4 and GluN1 was further validated by antibody-based Fluorescence Resonance Energy Transfer technology. Inhibition of the group I metabotropic glutamate receptor 5 with its selective antagonist, MTEP, abolished LPS-induced direct binding of TLR4 to GluN1. Therefore, these data demonstrated that GluN1 and TLR4 act reciprocally in response to LPS in N9 and EOC 20 microglial cells.

  4. Cysteinyl leukotrienes C4 and D4 downregulate human mast cell expression of toll-like receptors 1 through 7.

    PubMed

    Karpov, V; Ilarraza, R; Catalli, A; Kulka, M

    2018-01-01

    Cysteinyl leukotrienes (CysLT) are potent inflammatory lipid molecules that mediate some of the pathophysiological responses associated with asthma such as bronchoconstriction, vasodilation and increased microvascular permeability. As a result, CysLT receptor antagonists (LRA), such as montelukast, have been used to effectively treat patients with asthma. We have recently shown that mast cells are necessary modulators of innate immune responses to bacterial infection and an important component of this innate immune response may involve the production of CysLT. However, the effect of LRA on innate immune receptors, particularly on allergic effector cells, is unknown. This study determined the effect of CysLT on toll-like receptor (TLR) expression by the human mast cell line LAD2. Real-time PCR analysis determined that LTC4, LTD4 and LTE4 downregulated mRNA expression of several TLR. Specifically in human CD34+-derived human mast cells (HuMC), LTC4 inhibited expression of TLR1, 2, 4, 5, 6 and 7 while LTD4 inhibited expression of TLR1-7. Montelukast blocked LTC4-mediated downregulation of all TLR, suggesting that these effects were mediated by activation of the CysLT1 receptor (CysLT1R). Flow cytometry analysis confirmed that LTC4 downregulated surface expression of TLR2 which was blocked by montelukast. These data show that CysLT can modulate human mast cell expression of TLR and that montelukast may be beneficial for innate immune responses mediated by mast cells.

  5. Innate immunity and hepatocarcinoma: Can toll-like receptors open the door to oncogenesis?

    PubMed Central

    Lopes, Jorge André Gomes; Borges-Canha, Marta; Pimentel-Nunes, Pedro

    2016-01-01

    Hepatocarcinoma (HCC) is a highly prevalent cancer worldwide and its inflammatory background was established long ago. Recent studies have shown that innate immunity is closely related to the HCC carcinogenesis. An effective innate immunity response relies on the toll-like receptors (TLR) found in several different liver cells which, through different ligands and many signaling pathways can elicit, not only a pro-inflammatory but also an oncogenic or anti-oncogenic response. Our aim was to study the role of TLRs in the liver oncogenesis and as a consequence their value as potential therapeutic targets. We performed a systematic review of PubMed searching for original articles studying the relationship between HCC and TLRs until March 2015. TLR2 appears to be a fundamental stress-sensor as its absence reveals an augmented tendency to accumulate DNA-damages and to cell survival. However, pathways are still not fully understood as TLR2 up-regulation was also associated to enhanced tumorigenesis. TLR3 has a well-known protective role influencing crucial processes like angiogenesis, cell growth or proliferation. TLR4 works as an interesting epithelial-mesenchymal transition’s inducer and a promoter of cell survival probably inducing HCC carcinogenesis even though an anti-cancer role has already been observed. TLR9’s influence on carcinogenesis is also controversial and despite a potential anti-cancer capacity, a pro-tumorigenic role is more likely. Genetic polymorphisms in some TLRs have been found and its influence on the risk of HCC has been reported. As therapeutic targets, TLRs are already in use and have a great potential. In conclusion, TLRs have been shown to be an interesting influence on the HCC’s microenvironment, with TLR3 clearly determining an anti-tumour influence. TLR4 and TLR9 are considered to have a positive relationship with tumour development even though, in each of them anti-tumorigenic signals have been described. TLR2 presents a more

  6. Toll-like Receptors as a Target of Food-derived Anti-inflammatory Compounds*

    PubMed Central

    Shibata, Takahiro; Nakashima, Fumie; Honda, Kazuya; Lu, Yu-Jhang; Kondo, Tatsuhiko; Ushida, Yusuke; Aizawa, Koichi; Suganuma, Hiroyuki; Oe, Sho; Tanaka, Hiroshi; Takahashi, Takashi; Uchida, Koji

    2014-01-01

    Toll-like receptors (TLRs) play a key role in linking pathogen recognition with the induction of innate immunity. They have been implicated in the pathogenesis of chronic inflammatory diseases, representing potential targets for prevention/treatment. Vegetable-rich diets are associated with the reduced risk of several inflammatory disorders. In the present study, based on an extensive screening of vegetable extracts for TLR-inhibiting activity in HEK293 cells co-expressing TLR with the NF-κB reporter gene, we found cabbage and onion extracts to be the richest sources of a TLR signaling inhibitor. To identify the active substances, we performed activity-guiding separation of the principal inhibitors and identified 3-methylsulfinylpropyl isothiocyanate (iberin) from the cabbage and quercetin and quercetin 4′-O-β-glucoside from the onion, among which iberin showed the most potent inhibitory effect. It was revealed that iberin specifically acted on the dimerization step of TLRs in the TLR signaling pathway. To gain insight into the inhibitory mechanism of TLR dimerization, we developed a novel probe combining an isothiocyanate-reactive group and an alkyne functionality for click chemistry and detected the probe bound to the TLRs in living cells, suggesting that iberin disrupts dimerization of the TLRs via covalent binding. Furthermore, we designed a variety of iberin analogues and found that the inhibition potency was influenced by the oxidation state of the sulfur. Modeling studies of the iberin analogues showed that the oxidation state of sulfur might influence the global shape of the isothiocyanates. These findings establish the TLR dimerization step as a target of food-derived anti-inflammatory compounds. PMID:25294874

  7. Toll-Like Receptor 4 Expression in the Epithelium of Inflammatory Periapical Lesions.

    PubMed Central

    Leonardi, R.; Perrotta, R.E.; Musumeci, G.; Crimi, S.; dos Santos, J.N.; Rusu, M.C.; Bufo, P.; Barbato, E.; Pannone, G.

    2015-01-01

    Toll-like receptors (TLR) are essential for the innate immune response against invading pathogens and have been described in immunocompetent cells of areas affected by periapical disease. Besides initiating the inflammatory response, they also directly regulate epithelial cell proliferation and survival in a variety of settings. This study evaluates the in situ expression of TLR4 in periapical granulomas (PG) and radicular cysts, focusing on the epithelial compartment. Twenty-one periapical cysts (PC) and 10 PG were analyzed; 7 dentigerous non-inflamed follicular cyst (DC) served as control. TLR4 expression was assessed by immunohistochemistry. TLR4 immunoreaction products were detected in the epithelium of all specimens, with a higher percentage of immunostained cells in PG. Although TLR4 overexpression was detected in both PG and PC, there were differences that seemed to be related to the nature of the lesion, since in PG all epithelial cells of strands, islands and trabeculae were strongly immunoreactive for TLR4, whereas in PC only some areas of the basal and suprabasal epithelial layers were immunostained. This staining pattern is consistent with the action of TLR4: in PG it could promote formation of epithelial cell rests of Malassez and in epithelial strands and islands the enhancement of cell survival, proliferation and migration, whereas in PC TLR4 could protect the lining epithelium from extensive apoptosis. These findings go some way towards answering the intriguing question of why many epithelial strands or islands in PG and the lining epithelium of apical cysts regress after non-surgical endodontic therapy, and suggest that TLR4 plays a key role in the pathobiology of the inflammatory process related to periapical disease. PMID:26708181

  8. Cathelicidin Signaling via the Toll-Like Receptor Protects Against Colitis in Mice

    PubMed Central

    Koon, Hon Wai; Shih, David Quan; Chen, Jeremy; Bakirtzi, Kyriaki; Hing, Tressia C; Law, Ivy; Ho, Samantha; Ichikawa, Ryan; Zhao, Dezheng; Xu, Hua; Gallo, Richard; Dempsey, Paul; Cheng, Genhong; Targan, Stephan R; Pothoulakis, Charalabos

    2011-01-01

    Background & Aims Cathelicidin (encoded by Camp) is an anti-microbial peptide in the innate immune system. We examined whether macrophages express cathelicidin in colons of mice with experimental colitis and patients with inflammatory bowel disease; we investigated its signaling mechanisms. Methods Quantitative, real-time, reverse transcription PCR, bacterial 16S PCR, immunofluorescence, and small interfering (si)RNA analyses were performed. Colitis was induced in mice using sodium dextran sulfate (DSS); levels of cathelicidin were measured in human primary monocytes. Results Expression of cathelicidin increased in the inflamed colonic mucosa of mice with DSS-induced colitis, compared with controls. Cathelicidin expression localized to mucosal macrophages in inflamed colon tissues of patients and mice. Exposure of human primary monocytes to E coli DNA induced expression of Camp mRNA, which required signaling by ERK; expression was reduced by siRNAs against toll-like receptor (TLR)9 and MyD88. Intracolonic administration of bacterial DNA to wild-type mice induced expression of cathelicidin in colons of control mice and mice with DSS-induced colitis. Colon expression of cathelicidin was significantly reduced in TLR9 −/− mice with DSS-induced colitis. Compared with wild-type mice, Camp −/− mice developed a more severe form of DSS-induced colitis, particularly after intracolonic administration of E coli DNA. Expression of cathelicidin from bone marrow-derived immune cells regulated DSS induction of colitis in transplantation studies in mice. Conclusions Cathelicidin protects against colitis induction in mice. Increased expression of cathelicidin in monocytes and experimental models of colitis involves activation of TLR9–ERK signaling by bacterial DNA. This pathway might be involved in pathogenesis of ulcerative colitis. PMID:21762664

  9. Toll-Like Receptor 4 Engagement Mediates Prolyl Endopeptidase Release from Airway Epithelia via Exosomes.

    PubMed

    Szul, Tomasz; Bratcher, Preston E; Fraser, Kyle B; Kong, Michele; Tirouvanziam, Rabindra; Ingersoll, Sarah; Sztul, Elizabeth; Rangarajan, Sunil; Blalock, J Edwin; Xu, Xin; Gaggar, Amit

    2016-03-01

    Proteases are important regulators of pulmonary remodeling and airway inflammation. Recently, we have characterized the enzyme prolyl endopeptidase (PE), a serine peptidase, as a critical protease in the generation of the neutrophil chemoattractant tripeptide Pro-Gly-Pro (PGP) from collagen. However, PE has been characterized as a cytosolic enzyme, and the mechanism mediating PE release extracellularly remains unknown. We examined the role of exosomes derived from airway epithelia as a mechanism for PE release and the potential extracellular signals that regulate the release of these exosomes. We demonstrate a specific regulatory pathway of exosome release from airway epithelia and identify PE as novel exosome cargo. LPS stimulation of airway epithelial cells induces release of PE-containing exosomes, which is significantly attenuated by small interfering RNA depletion of Toll-like receptor 4 (TLR4). These differences were recapitulated upon intratracheal LPS administration in mice competent versus deficient for TLR4 signaling. Finally, sputum samples from subjects with cystic fibrosis colonized with Pseudomonas aeruginosa demonstrate elevated exosome content and increased PE levels. This TLR4-based mechanism highlights the first report of nonstochastic release of exosomes in the lung and couples TLR4 activation with matrikine generation. The increased quantity of these proteolytic exosomes in the airways of subjects with chronic lung disease highlights a new mechanism of injury and inflammation in the pathogenesis of pulmonary disorders.

  10. Evaluation of Safe Systemic Immunosuppression Created with Dexamethasone in Prevention of Capsular Contracture: A Glance to Distinct Perspectives with Toll-Like Receptors.

    PubMed

    Colak, Ozlem; Ozer, Kadri; Dikmen, Adile; Ozakinci, Hilal; Ozkaya, Ozay

    2018-03-21

    The toll-like receptors (TLRs) stand at the interface of innate immune activation. We hypothesize to decrease the response of innate immunity activated by TLR4 by a safe, short-term, systemic immunosuppression. Two silicone block implants were placed into two dorsal subcutaneous pockets in 32 rats that were subdivided into four groups: The two study groups were the IV DEX group (single intravenous injection of dexamethasone 1 h before surgery) and the IV DEX + IP DEX group (in addition to a single intravenous injection of dexamethasone 1 h before surgery, intraperitoneal dexamethasone was administered for 10 days after surgery), and the two control groups were the untreated control group and the saline-treated control group. After 10 weeks, all animals were killed to determine capsular thickness, inflammatory cell density, presence of pseudoepitheliomatous hyperplasia, edema, necrosis, vascularization, TLR4 expression and myofibroblast proliferation. No significant difference was observed in any parameter between the untreated and saline-treated control groups (p > 0.05). Capsular thickness, myofibroblast proliferation, TLR4 expression density were statistically different among study groups compared to control (p < 0.05). This study demonstrates the relationship between toll-like receptors and fibrous capsule after implant surgery. Decreasing the innate immunity by a safe, short-term perioperative systemic immunosuppression resulted in decreased TLR4 expression and myofibroblast differentiation which could be a new research field in profibrotic pathophysiology underlying breast capsule formation. This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

  11. A simple fluorescence-based assay for quantification of the Toll-Like Receptor agonist E6020 in vaccine formulations.

    PubMed

    Pollet, Jeroen; Versteeg, Leroy; Rezende, Wanderson; Strych, Ulrich; Gusovsky, Fabian; Hotez, Peter J; Bottazzi, Maria Elena

    2017-03-07

    Despite the generally accepted immunostimulatory effect of Toll-Like Receptor 4 (TLR4) agonists and their value as vaccine adjuvants, there remains a demand for fast and easy quantification assays for these TLR4 agonists in order to accelerate and improve vaccine formulation studies. A new medium-throughput method was developed for the quantification of the TLR4 agonist, E6020, independent of the formulation composition. The assay uses a fluorescent hydrazide (DCCH) to label the synthetic lipopolysaccharide (LPS) analog E6020 through its diketone groups. This novel, low-cost, and fluorescence based assay may obviate the need for traditional approaches that primarily rely on Fourier transform infrared spectroscopy (FTIR) or mass spectrometry. The experiments were performed in a wide diversity of vaccine formulations containing E6020 to assess method robustness and accuracy. The assay was also expanded to evaluate the loading efficiency of E6020 in poly(lactic-co-glycolic acid) (PLGA) micro-particles. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. Investigation of binding characteristics of immobilized toll-like receptor 3 with poly(I:C) for potential biosensor application.

    PubMed

    Topping, Kristin D; Kelly, David G

    2018-05-26

    Toll-like receptor 3 (TLR3), a pathogen recognition receptor of the innate immune response, recognizes and is activated by double-stranded RNA (dsRNA), which is indicative of viral exposure. A sensor design exercise was conducted, using surface plasmon resonance detection, through the examination of several immobilization approaches for TLR3 as a biorecognition element (BRE) onto a modified gold surface. To examine the TLR3-dsRNA interaction a synthetic analogue mimic, poly (I:C), was used. The interaction binding characteristics were determined and compared to literature data to establish the optimal immobilization method for the TLR3 BRE. A preliminary evaluation of the efficacy of the selected TLR3 surface as a broad-spectrum viral biosensor was also performed. Amine-coupling was found to be the most reliable method for manufacturing repeatable and consistent TLR3 BRE sensor surfaces, although this immobilization schema is not tailored to place the receptor in a spatially-specific orientation. The equilibrium dissociation constant (K D ) measured for this immobilized TLR3-poly (I:C) interaction was 117 ± 3.30 pM. This evaluation included a cross-reactivity study using a selection of purified E. coli and synthetic double- and single-stranded nucleic acids. The results of this design exercise and ligand binding study will inform future work towards the development of a broad-spectrum viral sensor device. Copyright © 2018. Published by Elsevier Inc.

  13. Intestinal ischemia/reperfusion injury triggers activation of innate toll-like receptor 4 and adaptive chemokine programs.

    PubMed

    Watson, M J; Ke, B; Shen, X-D; Gao, F; Busuttil, R W; Kupiec-Weglinski, J W; Farmer, D G

    2008-12-01

    Ischemia/reperfusion injury (IRI) is a major problem in intestinal transplantation. Toll-like receptor 4 (TLR4) has been implicated as a possible link between the innate and adaptive immune systems, however little data exists regarding TLR4 in intestinal IRI. The goal of this study is to evaluate the involvement of TLR4 in intestinal IRI and to assess the effect on T cell related chemokine programs. C57BL6 mice underwent 100 minutes of warm intestinal ischemia by SMA clamping. Control WT mice underwent laparotomy without vascular occlusion. Separate survival and analysis groups were performed, and intestinal tissue was harvested at 1 hour, 2 hours, 4 hours, and 24 hours post-reperfusion. Analysis included histology, CD3 immunostaining, myeloperoxidase activity, Western blot, and PCR. Survival was significantly worse in the IRI group vs control (50% vs. 100%). IRI caused severe histopathological injury including mucosal erosions and villous congestion and hemorrhage. Myeloperoxidase activity increased in a time-dependent manner after IRI (2.71 0.25 at 1 hour, 2.92 0.25 at 2 hours, 4 0.16 at 4 hours, 5.1 0.25 at 24 hours vs 0.47 0.11 controls, P < .05). Protein expression of TLR4 followed by NF-kappaB was increased after IRI. Additionally, mRNA production of IP-10, MIP-2, MCP-1, and RANTES was increased at all time-points, as was mRNA for ICAM-1 and E-selectin. This study is the first to demonstrate increased expression of TLR4 and NF-kappaB after warm intestinal IRI. This detrimental cascade may be initiated by TLR4 via NF-kappaB signaling pathways, implicating TLR4 as a potential therapeutic target for the prevention of intestinal IRI.

  14. Commensal-Associated Molecular Patterns Induce Selective Toll-Like Receptor-Trafficking from Apical Membrane to Cytoplasmic Compartments in Polarized Intestinal Epithelium

    PubMed Central

    Cario, Elke; Brown, Dennis; McKee, Mary; Lynch-Devaney, Kathryn; Gerken, Guido; Podolsky, Daniel K.

    2002-01-01

    Commensal-associated molecular patterns, the major products of nonpathogenic bacteria, are present at high concentrations at the apical surface of the intestinal epithelium. However, the nature of the interaction of commensal-associated molecular patterns with the lumenal surface of the epithelium has not been defined. We have recently demonstrated that intestinal epithelial cells constitutively express several Toll-like receptors (TLRs) in vitro and in vivo that seem to be the key receptors responsible for immune cell activation in response to various bacterial products. In this study we characterize the subcellular distribution of two major TLRs, TLR2 and TLR4, and their ligand-specific dynamic regulation in the model human intestinal epithelial cell line T84. Immunocytochemical studies indicate that TLR2 and TLR4 are constitutively expressed at the apical pole of differentiated T84 cells. After stimulation with lipopolysaccharide or peptidoglycan, TLRs selectively traffic to cytoplasmic compartments near the basolateral membrane. Thus, we demonstrate that TLRs are positioned at the apical pole where they are poised to monitor the sensitive balance of the lumenal microbial array. The results of this dynamic epithelial surveillance can then be conveyed to the underlying cell populations of the lamina propria via these innate immune pattern recognition receptors. PMID:11786410

  15. Brucella abortus Inhibits Major Histocompatibility Complex Class II Expression and Antigen Processing through Interleukin-6 Secretion via Toll-Like Receptor 2▿

    PubMed Central

    Barrionuevo, Paula; Cassataro, Juliana; Delpino, M. Victoria; Zwerdling, Astrid; Pasquevich, Karina A.; Samartino, Clara García; Wallach, Jorge C.; Fossati, Carlos A.; Giambartolomei, Guillermo H.

    2008-01-01

    The strategies that allow Brucella abortus to survive inside macrophages for prolonged periods and to avoid the immunological surveillance of major histocompatibility complex class II (MHC-II)-restricted gamma interferon (IFN-γ)-producing CD4+ T lymphocytes are poorly understood. We report here that infection of THP-1 cells with B. abortus inhibited expression of MHC-II molecules and antigen (Ag) processing. Heat-killed B. abortus (HKBA) also induced both these phenomena, indicating the independence of bacterial viability and involvement of a structural component of the bacterium. Accordingly, outer membrane protein 19 (Omp19), a prototypical B. abortus lipoprotein, inhibited both MHC-II expression and Ag processing to the same extent as HKBA. Moreover, a synthetic lipohexapeptide that mimics the structure of the protein lipid moiety also inhibited MHC-II expression, indicating that any Brucella lipoprotein could down-modulate MHC-II expression and Ag processing. Inhibition of MHC-II expression and Ag processing by either HKBA or lipidated Omp19 (L-Omp19) depended on Toll-like receptor 2 and was mediated by interleukin-6. HKBA or L-Omp19 also inhibited MHC-II expression and Ag processing of human monocytes. In addition, exposure to the synthetic lipohexapeptide inhibited Ag-specific T-cell proliferation and IFN-γ production of peripheral blood mononuclear cells from Brucella-infected patients. Together, these results indicate that there is a mechanism by which B. abortus may prevent recognition by T cells to evade host immunity and establish a chronic infection. PMID:17984211

  16. Toll-Like Receptor-Mediated Free Radical Generation in Clonorchis sinensis Excretory-Secretory Product-Treated Cholangiocarcinoma Cells.

    PubMed

    Bahk, Young Yil; Pak, Jhang Ho

    2016-10-01

    Clonorchiasis, caused by direct contact with Clonorchis sinensis worms and their excretory-secretory products (ESPs), is associated with chronic inflammation, malignant changes in bile ducts, and even cholangiocarcinogenesis. Our previous report revealed that intracellular free radicals enzymatically generated by C. sinensis ESPs cause NF-κB-mediated inflammation in human cholangiocarcinoma cells (HuCCT1). Therefore, the present study was conducted to examine the role of upstream Toll-like receptors (TLRs) on the initial host innate immune responses to infection. We found that treatment of HuCCT1 cells with native ESPs induced changes in TLR mRNA levels in a time-dependent manner, concomitant with the generation of free radicals. ESP-mediated free radical generation was markedly attenuated by preincubation of the cells with TLR1-4-neutralizing antibodies, indicating that at least TLR1 through 4 participate in stimulation of the host innate immune responses. These findings indicate that free radicals triggered by ESPs are critically involved in TLR signal transduction. Continuous signaling by this pathway may function in initiating C. sinensis infection-associated inflammation cascades, a detrimental event leading to progression to more severe hepatobiliary diseases.

  17. Curcumin Protects against Atherosclerosis in Apolipoprotein E-Knockout Mice by Inhibiting Toll-like Receptor 4 Expression.

    PubMed

    Zhang, Shanshan; Zou, Jun; Li, Peiyang; Zheng, Xiumei; Feng, Dan

    2018-01-17

    Toll-like receptor 4 (TLR4) has been reported to play a critical role in the pathogenesis of atherosclerosis, the current study aimed to investigate whether curcumin suppresses atherosclerosis development in ApoE-knockout (ApoE -/- ) mice by inhibiting TLR4 expression. ApoE -/- mice were fed a high-fat diet supplemented with or without curcumin (0.1% w/w) for 16 weeks. Curcumin supplementation significantly reduced TLR4 expression and macrophage infiltration in atherosclerotic plaques. Curcumin also reduced aortic interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α), vascular cell adhesion molecule-1 (VCAM-1) and intercellular adhesion molecule-1 (ICAM-1) expression, nuclear factor-κB (NF-κB) activity, and plasma IL-1β, TNF-α, soluble VCAM-1 and ICAM-1 levels. In addition, aortic sinus sections revealed that curcumin treatment reduced the extent of atherosclerotic lesions and inhibited atherosclerosis development. In vitro, curcumin inhibited NF-κB activation in macrophages and reduced TLR4 expression induced by lipopolysaccharide. Our results indicate that curcumin protects against atherosclerosis at least partially by inhibiting TLR4 expression and its related inflammatory reaction.

  18. Induction of human dendritic cell maturation using transfection with RNA encoding a dominant positive toll-like receptor 4.

    PubMed

    Cisco, Robin M; Abdel-Wahab, Zeinab; Dannull, Jens; Nair, Smita; Tyler, Douglas S; Gilboa, Eli; Vieweg, Johannes; Daaka, Yehia; Pruitt, Scott K

    2004-06-01

    Maturation of dendritic cells (DC) is critical for the induction of Ag-specific immunity. Ag-loaded DC matured with LPS, which mediates its effects by binding to Toll-like receptor 4 (TLR4), induce Ag-specific CTL in vitro and in vivo in animal models. However, clinical use of LPS is limited due to potential toxicity. Therefore, we sought to mimic the maturation-inducing effects of LPS on DC by stimulating TLR4-mediated signaling in the absence of exogenous LPS. We developed a constitutively active TLR4 (caTLR4) and demonstrated that transfection of human DC with RNA encoding caTLR4 led to IL-12 and TNF-alpha secretion. Transfection with caTLR4 RNA also induced a mature DC phenotype. Functionally, transfection of DC with caTLR4 RNA enhanced allostimulation of CD4(+) T cells. DC transfected with RNA encoding the MART (Melan-A/MART-1) melanoma Ag were then used to stimulate T cells in vitro. Cotransfection of these DC with caTLR4 RNA enhanced the generation of MART-specific CTL. This CTL activity was superior to that seen when DC maturation was induced using either LPS or a standard mixture of cytokines (TNF-alpha, IL-6, IL-1beta, and PGE(2)). We conclude that transfection of DC with RNA encoding a functional signaling protein, such as caTLR4, may provide a new tool for studying TLR signaling in DC and may be a promising approach for the induction of DC maturation for tumor immunotherapy.

  19. Human Myocardium Releases Heat Shock Protein 27 (HSP27) after Global Ischemia: The Proinflammatory Effect of Extracellular HSP27 through Toll-like Receptor (TLR)-2 and TLR4

    PubMed Central

    Jin, Chunhua; Cleveland, Joseph C; Ao, Lihua; Li, Jilin; Zeng, Qingchun; Fullerton, David A; Meng, Xianzhong

    2014-01-01

    The myocardial inflammatory response contributes to cardiac functional injury associated with heart surgery obligating global ischemia/reperfusion (I/R). Toll-like receptors (TLRs) play an important role in the mechanism underlying myocardial I/R injury. The aim of this study was to examine the release of small constitutive heat shock proteins (HSPs) from human and mouse myocardium after global ischemia and examine the role of extracellular small HSP in myocardial injury. HSP27 release was assessed by enzyme-linked immunosorbent assay. Anti-HSP27 was applied to evaluate the role of extracellular HSP27 in the postischemic inflammatory response and functional injury in mouse hearts. Isolated hearts and cultured coronary vascular endothelial cells were exposed to recombinant HSP27 to determine its effect on proinflammatory signaling and production of proinflammatory mediators. HSP27 levels were markedly elevated in coronary sinus blood of patients and in coronary effluent of mouse hearts after global ischemia. Neutralizing extracellular HSP27 suppressed myocardial nuclear factor (NF)-κB activation and interleukin (IL)-6 production and improved cardiac function in mouse hearts. Perfusion of HSP27 to mouse hearts induced NF-κB activation and IL-6 production and depressed contractility. Further, recombinant HSP27 induced NF-κB phosphorylation and upregulated monocyte chemoattractant protein (MCP)-1 and intercellular adhesion molecule (ICAM)-1 production in both human and mouse coronary vascular endothelial cells. TLR2 knockout (KO) or TLR4 mutation abolished NF-κB phosphorylation and reduced MCP-1 and ICAM-1 production induced by extracellular HSP27 in endothelial cells. In conclusion, these results show that the myocardium releases HSP27 after global ischemia and that extracellular HSP27 is proinflammatory and contributes to the inflammatory mechanism of myocardial functional injury. Both TLR2 and TLR4 are involved in mediating the proinflammatory effect of

  20. Human myocardium releases heat shock protein 27 (HSP27) after global ischemia: the proinflammatory effect of extracellular HSP27 through toll-like receptor (TLR)-2 and TLR4.

    PubMed

    Jin, Chunhua; Cleveland, Joseph C; Ao, Lihua; Li, Jilin; Zeng, Qingchun; Fullerton, David A; Meng, Xianzhong

    2014-06-09

    The myocardial inflammatory response contributes to cardiac functional injury associated with heart surgery obligating global ischemia/reperfusion (I/R). Toll-like receptors (TLRs) play an important role in the mechanism underlying myocardial I/R injury. The aim of this study was to examine the release of small constitutive heat shock proteins (HSPs) from human and mouse myocardium after global ischemia and examine the role of extracellular small HSP in myocardial injury. HSP27 release was assessed by enzyme-linked immunosorbent assay. Anti-HSP27 was applied to evaluate the role of extracellular HSP27 in the postischemic inflammatory response and functional injury in mouse hearts. Isolated hearts and cultured coronary vascular endothelial cells were exposed to recombinant HSP27 to determine its effect on proinflammatory signaling and production of proinflammatory mediators. HSP27 levels were markedly elevated in coronary sinus blood of patients and in coronary effluent of mouse hearts after global ischemia. Neutralizing extracellular HSP27 suppressed myocardial nuclear factor (NF)-κB activation and interleukin (IL)-6 production and improved cardiac function in mouse hearts. Perfusion of HSP27 to mouse hearts induced NF-κB activation and IL-6 production and depressed contractility. Further, recombinant HSP27 induced NF-κB phosphorylation and upregulated monocyte chemoattractant protein (MCP)-1 and intercellular adhesion molecule (ICAM)-1 production in both human and mouse coronary vascular endothelial cells. TLR2 knockout (KO) or TLR4 mutation abolished NF-κB phosphorylation and reduced MCP-1 and ICAM-1 production induced by extracellular HSP27 in endothelial cells. In conclusion, these results show that the myocardium releases HSP27 after global ischemia and that extracellular HSP27 is proinflammatory and contributes to the inflammatory mechanism of myocardial functional injury. Both TLR2 and TLR4 are involved in mediating the proinflammatory effect of

  1. [Effect of metformin on the expression of tumor necrosis factor-α, Toll like receptors 2/4 and C reactive protein in obese type-2 diabetic patients].

    PubMed

    Andrews, Mónica; Soto, Néstor; Arredondo, Miguel

    2012-11-01

    The pharmacological action of metformin goes beyond mere glycemic control, decreasing markers of inflammation and contributing to the reduction of oxidative stress. To evaluate biochemical, anthropometric and pro-inflammatory markers in obese type 2 diabetic patients treated or not with metformin. Obese patients with type 2 diabetes were invited to participate in the study if they were aged more than 40 years, were not receiving insulin, did not have cardiovascular diseases and were not taking anti-inflammatory drugs. A pharmacological history was taken and patients were stratified in two groups whether they were using metformin or not. A fasting blood sample was obtained to measure blood glucose, insulin, lipid levels, C reactive protein (hsCRP) and to isolate peripheral blood mononuclear cells. RNA was isolated from these cells to measure expression of tumor necrosis factor-α (TNF-α), Interleukin-6 (IL-6), nuclear factor kappa-light-chain-enhancer of activated B cells (NF-kB), Toll-Like Receptor 2/4 (TLR 2/4) and beta-2-microglobulin (B2M). Thirty participants were studied. Of these, 16 subjects aged 54.4 ± 5.5years were treated with metformin and 14 subjects aged 54.9 ± 6.4 years did not receive the drug. Participants receiving metformin had lower levels of hsCRP and lower mRNA relative abundance of TNF-α and TLR 2/4. There were no differences in glucose levels or lipid profile between both groups. Obese diabetic patients treated with metformin had lower levels of hsCRP expression of TNF-α and TLR 2/4, than their counterparts not receiving the drug.

  2. Retraction Statement: Anti-inflammatory properties of tianeptine on lipopolysaccharide-induced changes in microglial cells involve toll-like receptor-related pathways.

    PubMed

    2017-09-01

    'Anti-inflammatory properties of tianeptine on lipopolysaccharide-induced changes in microglial cells involve toll-like receptor-related pathways' by Slusarczyk, J., Trojan, E., Glombik, K., Piotrowska, A., Budziszewska, B., Kubera, M., Popiolek-Barczyk, K., Lason, W., Mika, J. and Basta-Kaim, A. The above article from the Journal of Neurochemistry published on 14 February 2016 on Wiley Online Library ( www.onlinelibrary.com), and in Volume 136, pp. 958-970, is being retracted by agreement between the corresponding author Agnieszka Basta-Kaim, the Journal's Editor-in-Chief Jörg Schulz, and John Wiley & Sons Ltd. The Editorial Office was alerted by a science journalist that the same Western Blot lane had been used to represent two different proteins. The Western Blot signal of iNOS in Fig. 4a was supposedly identical to the Western Blot signal of phospho-JNK in Fig. 6b. The corresponding author stated that "on the final step of figure 6 preparation the first author made, by mistake, an incorrect attachment of representative p-JNK blots." A corrected Fig. 6b is enclosed below. The second concern reaching the Editorial Office was that the same Western Blot signal appeared to have been used to represent two different experimental conditions: the iNOS control signal (-/- LPS/TIA Fig. 4a) appears as a horizontal and vertical mirror image of the last signal in this line (+/10 LPS/TIA Fig. 4a). The raw membrane which was used to produce Fig. 4a is enclosed on the next page and highlights the steps that were undertaken during figure preparation. Although the initial concern was not proven, concerns remained regarding the question how an inadvertent flipping of the first Western blot lane could happen. A corrected Fig. 4a prepared by the corresponding author from the raw image of iNOS western blot depicted above, without flipped first lane, is presented below: Although the corresponding author provided a large amount of evidence to explain disparities in the

  3. Cross-talk between toll-like receptor 4 (TLR4) and proteinase-activated receptor 2 (PAR(2) ) is involved in vascular function.

    PubMed

    Bucci, M; Vellecco, V; Harrington, L; Brancaleone, V; Roviezzo, F; Mattace Raso, G; Ianaro, A; Lungarella, G; De Palma, R; Meli, R; Cirino, G

    2013-01-01

    Proteinase-activated receptors (PARs) and toll-like receptors (TLRs) are involved in innate immune responses. The aim of this study was to evaluate the possible cross-talk between PAR(2) and TLR4 in vessels in physiological condition and how it varies following stimulation of TLR4 by using in vivo and ex vivo models. Thoracic aortas were harvested from both naïve and endotoxaemic rats for in vitro studies. Arterial blood pressure was monitored in anaesthetized rats in vivo. LPS was used as a TLR4 agonist while PAR(2) activating peptide (AP) was used as a PAR(2) agonist. Aortas harvested from TLR4(-/-) mice were also used to characterize the PAR(2) response. PAR(2) , but not TLR4, expression was enhanced in aortas of endotoxaemic rats. PAR(2) AP-induced vasorelaxation was increased in aortic rings of LPS-treated rats. TLR4 inhibitors, curcumine and resveratrol, reduced PAR(2) AP-induced vasorelaxation and PAR(2) AP-induced hypotension in both naïve and endotoxaemic rats. Finally, in aortic rings from TLR4(-/-) mice, the expression of PAR(2) was reduced and the PAR(2) AP-induced vasodilatation impaired compared with those from wild-type mice and both resveratrol and curcumine were ineffective. Cross-talk between PAR(2) and TLR4 contributes to vascular homeostasis. © 2012 The Authors. British Journal of Pharmacology © 2012 The British Pharmacological Society.

  4. Cross-talk between toll-like receptor 4 (TLR4) and proteinase-activated receptor 2 (PAR2) is involved in vascular function

    PubMed Central

    Bucci, M; Vellecco, V; Harrington, L; Brancaleone, V; Roviezzo, F; Mattace Raso, G; Ianaro, A; Lungarella, G; De Palma, R; Meli, R; Cirino, G

    2013-01-01

    Background and Purpose Proteinase-activated receptors (PARs) and toll-like receptors (TLRs) are involved in innate immune responses. The aim of this study was to evaluate the possible cross-talk between PAR2 and TLR4 in vessels in physiological condition and how it varies following stimulation of TLR4 by using in vivo and ex vivo models. Experimental Approach Thoracic aortas were harvested from both naïve and endotoxaemic rats for in vitro studies. Arterial blood pressure was monitored in anaesthetized rats in vivo. LPS was used as a TLR4 agonist while PAR2 activating peptide (AP) was used as a PAR2 agonist. Aortas harvested from TLR4–/– mice were also used to characterize the PAR2 response. Key Results PAR2, but not TLR4, expression was enhanced in aortas of endotoxaemic rats. PAR2AP-induced vasorelaxation was increased in aortic rings of LPS-treated rats. TLR4 inhibitors, curcumine and resveratrol, reduced PAR2AP-induced vasorelaxation and PAR2AP-induced hypotension in both naïve and endotoxaemic rats. Finally, in aortic rings from TLR4–/– mice, the expression of PAR2 was reduced and the PAR2AP-induced vasodilatation impaired compared with those from wild-type mice and both resveratrol and curcumine were ineffective. Conclusions and Implications Cross-talk between PAR2 and TLR4 contributes to vascular homeostasis. PMID:22957757

  5. Variants in toll-like receptor 9 gene influence susceptibility to tuberculosis in a Mexican population.

    PubMed

    Torres-García, Diana; Cruz-Lagunas, Alfredo; García-Sancho Figueroa, Ma Cecilia; Fernández-Plata, Rosario; Baez-Saldaña, Renata; Mendoza-Milla, Criselda; Barquera, Rodrigo; Carrera-Eusebio, Aida; Ramírez-Bravo, Salomón; Campos, Lizeth; Angeles, Javier; Vargas-Alarcón, Gilberto; Granados, Julio; Gopal, Radha; Khader, Shabaana A; Yunis, Edmond J; Zuñiga, Joaquin

    2013-09-21

    The control of Mycobacterium tuberculosis (Mtb) infection begins with the recognition of mycobacterial structural components by toll like receptors (TLRs) and other pattern recognition receptors. Our objective was to determine the influence of TLRs polymorphisms in the susceptibility to develop tuberculosis (TB) in Amerindian individuals from a rural area of Oaxaca, Mexico with high TB incidence. We carried out a case-control association community based study, genotyping 12 polymorphisms of TLR2, TLR4, TLR6 and TLR9 genes in 90 patients with confirmed pulmonary TB and 90 unrelated exposed but asymptomatic household contacts. We found a significant increase in the frequency of the allele A of the TLR9 gene polymorphism rs352139 (A>G) in the group of TB patients (g.f. = 0.522) when compared with controls (g.f. = 0.383), (Pcorr = 0.01, OR = 1.75). Under the recessive model (A/G + A/A vs G/G) this polymorphism was also significantly associated with TB (Pcorr = 0.01, OR= 2.37). The association of the SNP rs352139 was statistically significant after adjustment by age, gender and comorbidities by regression logistic analysis (Dominant model: p value = 0.016, OR = 2.31; Additive model: p value = 0.023, OR = 1.68). The haplotype GAA of TLR9 SNPs was also associated with TB susceptibility (Pcorr = 0.02). Differences in the genotype or allele frequencies of TLR2, TLR4 and TLR6 polymorphisms between TB patients and healthy contacts were not detected. Our study suggests that the allele A of the intronic polymorphism rs352139 on TLR9 gene might contribute to the risk of developing TB in Mexican Amerindians.

  6. Differential immunomodulatory activity of tumor cell death induced by cancer therapeutic toll-like receptor ligands.

    PubMed

    Klein, Johanna C; Wild, Clarissa A; Lang, Stephan; Brandau, Sven

    2016-06-01

    Synthetic toll-like receptor (TLR) ligands stimulate defined immune cell subsets and are currently tested as novel immunotherapeutic agents against cancer with, however, varying clinical efficacy. Recent data showed the expression of TLR receptors also on tumor cells. In this study we investigated immunological events associated with the induction of tumor cell death by poly(I:C) and imiquimod. A human head and neck squamous cell carcinoma (HNSCC) cell line was exposed to poly(I:C) and imiquimod, which were delivered exogenously via culture medium or via electroporation. Cell death and cell biological consequences thereof were analyzed. For in vivo analyses, a human xenograft and a syngeneic immunocompetent mouse model were used. Poly(I:C) induced cell death only if delivered by electroporation into the cytosol. Cell death induced by poly(I:C) resulted in cytokine release and activation of monocytes in vitro. Monocytes activated by the supernatant of cancer cells previously exposed to poly(I:C) recruited significantly more Th1 cells than monocytes exposed to control supernatants. If delivered exogenously, imiquimod also induced tumor cell death and some release of interleukin-6, but cell death was not associated with release of Th1 cytokines, interferons, monocyte activation and Th1 recruitment. Interestingly, intratumoral injection of poly(I:C) triggered tumor cell death in tumor-bearing mice and reduced tumor growth independent of TLR signaling on host cells. Imiquimod did not affect tumor size. Our data suggest that common cancer therapeutic RNA compounds can induce functionally diverse types of cell death in tumor cells with implications for the use of TLR ligands in cancer immunotherapy.

  7. Toll-Like Receptor Signaling and SIGIRR in Renal Fibrosis upon Unilateral Ureteral Obstruction

    PubMed Central

    Allam, Ramanjaneyulu; Ryu, Mi; Clauss, Sebastian; Susanti, Heni Eka; Römmele, Christoph; Garlanda, Cecilia; Mantovani, Alberto; Anders, Hans-Joachim

    2011-01-01

    Innate immune activation via IL-1R or Toll-like receptors (TLR) contibutes to acute kidney injury but its role in tissue remodeling during chronic kidney disease is unclear. SIGIRR is an inhibitor of TLR-induced cytokine and chemokine expression in intrarenal immune cells, therefore, we hypothesized that Sigirr-deficiency would aggravate postobstructive renal fibrosis. The expression of TLRs as well as endogenous TLR agonists increased within six days after UUO in obstructed compared to unobstructed kidneys while SIGIRR itself was downregulated by day 10. However, lack of SIGIRR did not affect the intrarenal mRNA expression of proinflammatory and profibrotic mediators as well as the numbers of intrarenal macrophages and T cells or morphometric markers of tubular atrophy and interstitial fibrosis. Because SIGIRR is known to block TLR/IL-1R signaling at the level of the intracellular adaptor molecule MyD88 UUO experiments were also performed in mice deficient for either MyD88, TLR2 or TLR9. After UUO there was no significant change of tubular interstitial damage and interstitial fibrosis in neither of these mice compared to wildtype counterparts. Additional in-vitro studies with CD90+ renal fibroblasts revealed that TLR agonists induce the expression of IL-6 and MCP-1/CCL2 but not of TGF-β, collagen-1α or smooth muscle actin. Together, postobstructive renal interstitial fibrosis and tubular atrophy develop independent of SIGIRR, TLR2, TLR9, and MyD88. These data argue against a significant role of these molecules in renal fibrosis. PMID:21544241

  8. Association of Toll-like receptor 4 with hepatitis A virus infection in Assam.

    PubMed

    Kashyap, P; Deka, M; Medhi, S; Dutta, S; Kashyap, K; Kumari, N

    Hepatitis A virus (HAV) which causes liver disease is recognized by Toll-like receptors (TLRs) through the viral nucleic acid, initiating the host defense response. The study aims to analyze the role of TLR4 rs11536889 polymorphism in the pathogenesis of hepatitis A cases from Assam. There was significant correlation between TLR4 SNP G/C (rs11536889) and between acute viral hepatitis (AVH) A cases and controls. The correlation of the 3 different genotypes GG, GC and CC of TLR4 rs11536889 with the TLR4 mRNA expression level in all the HAV cases groups have been found to be statistically significant (p <0.001). TLR4 expression was most significantly upregulated in the acute HAV cases, HAV with cholestasis cases and even the HAV caused fulminant hepatitis failure (FHF) cases with the CC genotype of TLR4 rs11536889. The upregulation is mostly seen in the cases with the CC genotype of TLR4 rs11536889 and thus indicates that the mutant variant of TLR4 rs11536899 (CC) may have an effect on the expression of TLR4 at the transcription level. Our study did not show any significant association between AVH and HAV caused FHF (p = 0.32, OR = 0; p = 0.59, OR = 2.06 at 95% CI) among the genotypes GG, GC and CC. Our data suggest that TLR4 gene polymorphism rs11536889 may play a prominent role in HAV disease susceptibility and TLR4 expression in population from Assam.

  9. Toll-Like Receptor Activation by Generalized Modules for Membrane Antigens from Lipid A Mutants of Salmonella enterica Serovars Typhimurium and Enteritidis.

    PubMed

    Rossi, Omar; Caboni, Mariaelena; Negrea, Aurel; Necchi, Francesca; Alfini, Renzo; Micoli, Francesca; Saul, Allan; MacLennan, Calman A; Rondini, Simona; Gerke, Christiane

    2016-04-01

    Invasive nontyphoidal Salmonella (iNTS) disease is a neglected disease with high mortality in children and HIV-positive individuals in sub-Saharan Africa, caused primarily by Africa-specific strains of Salmonella enterica serovars Typhimurium and Enteritidis. A vaccine using GMMA (generalized modules for membrane antigens) fromS.Typhimurium andS.Enteritidis containing lipid A modifications to reduce potential in vivo reactogenicity is under development. GMMA with penta-acylated lipid A showed the greatest reduction in the level of cytokine release from human peripheral blood monocytes from that for GMMA with wild-type lipid A. Deletion of the lipid A modification genes msbB and pagP was required to achieve pure penta-acylation. Interestingly, ΔmsbBΔ pagP GMMA from S. Enteritidis had a slightly higher stimulatory potential than those from S. Typhimurium, a finding consistent with the higher lipopolysaccharide (LPS) content and Toll-like receptor 2 (TLR2) stimulatory potential of the former. Also, TLR5 ligand flagellin was found in Salmonella GMMA. No relevant contribution to the stimulatory potential of GMMA was detected even when the flagellin protein FliC from S. Typhimurium was added at a concentration as high as 10% of total protein, suggesting that flagellin impurities are not a major factor for GMMA-mediated immune stimulation. Overall, the stimulatory potential of S. Typhimurium and S. Enteritidis ΔmsbB ΔpagP GMMA was close to that of Shigella sonnei GMMA, which are currently in phase I clinical trials. Copyright © 2016 Rossi et al.

  10. Screening toll-like receptor markers to predict latent tuberculosis infection and subsequent tuberculosis disease in a Chinese population.

    PubMed

    Wu, Linlin; Hu, Yi; Li, Dange; Jiang, Weili; Xu, Biao

    2015-04-01

    We investigated whether polymorphisms in the toll-like receptor genes or gene-gene interactions are associated with susceptibility to latent tuberculosis infection (LTBI) or subsequent pulmonary tuberculosis (PTB) in a Chinese population. Two matched case-control studies were undertaken. Previously reported polymorphisms in the toll-like receptors (TLRs) were compared between 422 healthy controls (HC) and 205 LTBI patients and between 205 LTBI patients and 109 PTB patients, to assess whether these polymorphisms and their interactions are associated with LTBI or PTB. A PCR-based restriction fragment length polymorphism analysis was used to detect genetic polymorphisms in the TLR genes. Nonparametric multifactor dimensionality reduction (MDR) was used to analyze the effects of interactions between complex disease genes and other genes or environmental factors. Sixteen markers in TLR1, TLR2, TLR4, TLR6, TLR8, TLR9, and TIRAP were detected. In TLR2, the frequencies of the CC genotype (OR = 2.262; 95% CI: 1.433-3.570) and C allele (OR = 1.566; 95% CI: 1.223-1.900) in single-nucleotide polymorphism (SNP) rs3804100 were significantly higher in the LTBI group than in the HC group, whereas the GA genotype of SNP rs5743708 was associated with PTB (OR = 6.087; 95% CI: 1.687-21.968). The frequencies of the GG genotype of SNP rs7873784 in TLR4 (OR = 2.136; 95% CI: 1.312-3.478) and the CC genotype of rs3764879 in TLR8 (OR = 1.982; 95% CI: 1.292-3.042) were also significantly higher in the PTB group than in the HC group. The TC genotype frequency of SNP rs5743836 in TLR9 was significantly higher in the LTBI group than in the HC group (OR = 1.664; 95% CI: 1.201-2.306). An MDR analysis of gene-gene and gene-environment interactions identified three SNPs (rs10759932, rs7873784, and rs10759931) that predicted LTBI with 84% accuracy (p = 0.0004) and three SNPs (rs3804100, rs1898830, and rs10759931) that predicted PTB with 80% accuracy (p = 0.0001). Our

  11. Cross talk between AT1 receptors and Toll-like receptor 4 in microglia contributes to angiotensin II-derived ROS production in the hypothalamic paraventricular nucleus.

    PubMed

    Biancardi, Vinicia Campana; Stranahan, Alexis M; Krause, Eric G; de Kloet, Annette D; Stern, Javier E

    2016-02-01

    ANG II is thought to increase sympathetic outflow by increasing oxidative stress and promoting local inflammation in the paraventricular nucleus (PVN) of the hypothalamus. However, the relative contributions of inflammation and oxidative stress to sympathetic drive remain poorly understood, and the underlying cellular and molecular targets have yet to be examined. ANG II has been shown to enhance Toll-like receptor (TLR)4-mediated signaling on microglia. Thus, in the present study, we aimed to determine whether ANG II-mediated activation of microglial TLR4 signaling is a key molecular target initiating local oxidative stress in the PVN. We found TLR4 and ANG II type 1 (AT1) receptor mRNA expression in hypothalamic microglia, providing molecular evidence for the potential interaction between these two receptors. In hypothalamic slices, ANG II induced microglial activation within the PVN (∼65% increase, P < 0.001), an effect that was blunted in the absence of functional TLR4. ANG II increased ROS production, as indicated by dihydroethidium fluorescence, within the PVN of rats and mice (P < 0.0001 in both cases), effects that were also dependent on the presence of functional TLR4. The microglial inhibitor minocycline attenuated ANG II-mediated ROS production, yet ANG II effects persisted in PVN single-minded 1-AT1a knockout mice, supporting the contribution of a non-neuronal source (likely microglia) to ANG II-driven ROS production in the PVN. Taken together, these results support functional interactions between AT1 receptors and TLR4 in mediating ANG II-dependent microglial activation and oxidative stress within the PVN. More broadly, our results support a functional interaction between the central renin-angiotensin system and innate immunity in the regulation of neurohumoral outflows from the PVN. Copyright © 2016 the American Physiological Society.

  12. Epstein-Barr virus (EBV)–encoded small RNA is released from EBV-infected cells and activates signaling from toll-like receptor 3

    PubMed Central

    Iwakiri, Dai; Zhou, Li; Samanta, Mrinal; Matsumoto, Misako; Ebihara, Takashi; Seya, Tsukasa; Imai, Shosuke; Fujieda, Mikiya; Kawa, Keisei

    2009-01-01

    Epstein-Barr virus–encoded small RNA (EBER) is nonpolyadenylated, noncoding RNA that forms stem-loop structure by intermolecular base-pairing, giving rise to double-stranded RNA (dsRNA)–like molecules, and exists abundantly in EBV-infected cells. Here, we report that EBER induces signaling from the Toll-like receptor 3 (TLR3), which is a sensor of viral double-stranded RNA (dsRNA) and induces type I IFN and proinflammatory cytokines. A substantial amount of EBER, which was sufficient to induce signaling from TLR3, was released from EBV-infected cells, and the majority of the released EBER existed as a complex with a cellular EBER-binding protein La, suggesting that EBER was released from the cells by active secretion of La. Sera from patients with infectious mononucleosis (IM), chronic active EBV infection (CAEBV), and EBV-associated hemophagocytic lymphohistiocytosis (EBV-HLH), whose general symptoms are caused by proinflammatory cytokines contained EBER, and addition of RNA purified from the sera into culture medium induced signaling from TLR3 in EBV-transformed lymphocytes and peripheral mononuclear cells. Furthermore, DCs treated with EBER showed mature phenotype and antigen presentation capacity. These findings suggest that EBER, which is released from EBV-infected cells, is responsible for immune activation by EBV, inducing type I IFN and proinflammatory cytokines. EBER-induced activation of innate immunity would account for immunopathologic diseases caused by active EBV infection. PMID:19720839

  13. A Single Nucleotide Polymorphism in 3′-Untranslated Region Contributes to the Regulation of Toll-like Receptor 4 Translation*

    PubMed Central

    Sato, Kayo; Yoshimura, Atsutoshi; Kaneko, Takashi; Ukai, Takashi; Ozaki, Yukio; Nakamura, Hirotaka; Li, Xinyue; Matsumura, Hiroyoshi; Hara, Yoshitaka; Ogata, Yorimasa

    2012-01-01

    We have previously shown that a single nucleotide polymorphism rs11536889 in the 3′-untranslated region (UTR) of TLR4 was associated with periodontitis. In this study the effects of this single nucleotide polymorphism on Toll-like receptor (TLR) 4 expression were investigated. Monocytes from subjects with the C/C genotype expressed higher levels of TLR4 on their surfaces than those from subjects with the other genotypes. Peripheral blood mononuclear cells (PBMCs) from the C/C and G/C subjects secreted higher levels of IL-8 in response to lipopolysaccharide (LPS), a TLR4 ligand, than the cells from the G/G subjects. However, there was no significant difference in TLR4 mRNA levels in PBMCs from the subjects with each genotype. After stimulation with tripalmitoylated CSK4 (Pam3CSK4), TLR4 mRNA levels increased in PBMCs from both the C/C and G/G subjects, whereas TLR4 protein levels increased in PBMCs from the C/C but not G/G subjects. Transient transfection of a series of chimeric luciferase constructs revealed that a fragment of 3′-UTR containing rs11536889 G allele, but not C allele, suppressed luciferase activity induced by LPS or IL-6. Two microRNAs, hsa-miR-1236 and hsa-miR-642a, were predicted to bind to rs11536889 G allele. Inhibition of these microRNAs reversed the suppressed luciferase activity. These microRNA inhibitors also up-regulated endogenous TLR4 protein on THP-1 cells (the G/G genotype) after LPS stimulation. Furthermore, mutant microRNAs that bind to the C allele inhibited the luciferase activity of the construct containing the C allele. These results indicate that genetic variation of rs11536889 contributes to translational regulation of TLR4, possibly by binding to microRNAs. PMID:22661708

  14. Polymorphisms of glutathione S-transferase π 1 and toll-like receptors 2 and 9: Association with breast cancer susceptibility

    PubMed Central

    AL-HARRAS, MOHAMMAD F.; HOUSSEN, MAHA E.; SHAKER, MOHAMED E.; FARAG, KAMEL; FAROUK, OMAR; MONIR, REHAN; EL-MAHDY, RASHA; ABO-HASHEM, EKBAL M.

    2016-01-01

    Polymorphisms in antioxidant enzymes and innate immune receptors have been implicated in the development of various types of cancer. The present study aimed to investigate whether polymorphisms of glutathione S-transferase π 1 (GSTP1) and toll-like receptors (TLRs) 2 and 9 are associated with susceptibility to breast cancer among females. The study was conducted on 72 Egyptian female patients with breast cancer, along with 100 healthy volunteers. Polymorphisms of GSTP1 (codon 105 Ile/Val) and TLR9 rs187084 (1237T/C) genes were assessed by polymerase chain reaction (PCR)-restriction fragment length polymorphism, while the −196 to −174 deletion/insertion (del/ins) polymorphism of TLR2 was detected by PCR. The results indicated a decrease in GSTP1 Val allele frequency in breast cancer patients compared with healthy controls, at rates of 22.9 vs. 32.5%, respectively. In addition, the breast cancer group demonstrated a decreased TLR9 C allele frequency compared with the control group, at rates of 36.1 vs. 51.5%, respectively (P=0.0047). A non-significant difference was detected in the frequency of the TLR2 −196 to −174 del allele in breast cancer patients when compared to normal controls. In conclusion, these results suggested that the GSTP1 Val and TLR9 1237C alleles, but not TLR2 −196 to −174 del, are likely to be associated with breast cancer development among females. PMID:26998146

  15. Polymorphisms of glutathione S-transferase π 1 and toll-like receptors 2 and 9: Association with breast cancer susceptibility.

    PubMed

    Al-Harras, Mohammad F; Houssen, Maha E; Shaker, Mohamed E; Farag, Kamel; Farouk, Omar; Monir, Rehan; El-Mahdy, Rasha; Abo-Hashem, Ekbal M

    2016-03-01

    Polymorphisms in antioxidant enzymes and innate immune receptors have been implicated in the development of various types of cancer. The present study aimed to investigate whether polymorphisms of glutathione S-transferase π 1 (GSTP1) and toll-like receptors (TLRs) 2 and 9 are associated with susceptibility to breast cancer among females. The study was conducted on 72 Egyptian female patients with breast cancer, along with 100 healthy volunteers. Polymorphisms of GSTP1 (codon 105 Ile/Val) and TLR9 rs187084 (1237T/C) genes were assessed by polymerase chain reaction (PCR)-restriction fragment length polymorphism, while the -196 to -174 deletion/insertion (del/ins) polymorphism of TLR2 was detected by PCR. The results indicated a decrease in GSTP1 Val allele frequency in breast cancer patients compared with healthy controls, at rates of 22.9 vs. 32.5%, respectively. In addition, the breast cancer group demonstrated a decreased TLR9 C allele frequency compared with the control group, at rates of 36.1 vs. 51.5%, respectively (P=0.0047). A non-significant difference was detected in the frequency of the TLR2 -196 to -174 del allele in breast cancer patients when compared to normal controls. In conclusion, these results suggested that the GSTP1 Val and TLR9 1237C alleles, but not TLR2 -196 to -174 del, are likely to be associated with breast cancer development among females.

  16. Toll-like Receptor 2 Signalling and the Lysosomal Machinery in Barrett's Esophagus.

    PubMed

    Verbeek, Romy E; Siersema, Peter D; Vleggaar, Frank P; Ten Kate, Fiebo J; Posthuma, George; Souza, Rhonda F; de Haan, Judith; van Baal, Jantine W P M

    2016-09-01

    Inflammation plays an important role in the development of esophageal adenocarcinoma and its metaplastic precursor lesion, Barrett's esophagus. Toll-like receptor (TLR) 2 signalling and lysosomal function have been linked to inflammation-associated carcinogenesis. We examined the expression of TLR2 in the esophagus and the effect of long-term TLR2 activation on morphological changes and expression of factors involved in lysosomal function in a Barrett's esophagus epithelium cell line. TLR2 expression in normal squamous esophagus, reflux esophagitis, Barrett's esophagus and esophageal adenocarcinoma biopsies was assessed with Q-RT-PCR, in situ hybridization and immunohistochemistry. Barrett's esophagus epithelium cells (BAR-T) were incubated with acid and bile salts in the presence or absence of the TLR2 agonist Pam3CSK4 for a period up to 4 weeks. Morphological changes were assessed with electron microscopy, while Q-RT-PCR was used to determine the expression of lysosomal enzymes (Cathepsin B and C) and factors involved in endocytosis (LAMP-1 and M6PR) and autophagy (LC3 and Rab7). TLR2 was expressed in normal squamous esophagus, reflux esophagitis, Barrett's esophagus but was most prominent in esophageal adenocarcinoma. Long-term TLR2 activation in acid and bile salts exposed BAR-T cells resulted in more and larger lysosomes, more mitochondria and increased expression of LAMP-1, M6PR, Cathepsin B and C when compared to BAR-T cells incubated with acid and bile salts but no TLR2 agonist. Factors associated with autophagy (LC3 and Rab7) expression remained largely unchanged. Activation of TLR2 in acid and bile salts exposed Barrett epithelium cells resulted in an increased number of mitochondria and lysosomes and increased expression of lysosomal enzymes and factors involved in endocytosis.

  17. Lipopolysaccharide and toll-like receptor 4 in dogs with congenital portosystemic shunts.

    PubMed

    Tivers, M S; Lipscomb, V J; Smith, K C; Wheeler-Jones, C P D; House, A K

    2015-12-01

    Surgical attenuation of a congenital portosystemic shunt (CPSS) results in increased portal vein perfusion, liver growth and clinical improvement. Portal lipopolysaccharide (LPS) is implicated in liver regeneration via toll-like receptor (TLR) 4 mediated cytokine activation. The aim of this study was to investigate factors associated with LPS in dogs with CPSS. Plasma LPS concentrations were measured in the peripheral and portal blood using a limulus amoebocyte lysate (LAL) assay. LPS concentration was significantly greater in the portal blood compared to peripheral blood in dogs with CPSS (P = 0.046) and control dogs (P = 0.002). LPS concentrations in the peripheral (P = 0.012) and portal (P = 0.005) blood of dogs with CPSS were significantly greater than those of control dogs. The relative mRNA expression of cytokines and TLRs was measured in liver biopsies from dogs with CPSS using quantitative PCR. TLR4 expression significantly increased following partial CPSS attenuation (P = 0.020). TLR4 expression was significantly greater in dogs that tolerated complete CPSS attenuation (P = 0.011) and those with good portal blood flow on pre-attenuation (P = 0.004) and post-attenuation (P = 0.015) portovenography. Serum interleukin (IL)-6 concentration was measured using a canine specific ELISA and significantly increased 24 h following CPSS attenuation (P < 0.001). Portal LPS was increased in dogs with CPSS, consistent with decreased hepatic clearance. TLR4 mRNA expression was significantly associated with portal blood flow and increased following surgery. These findings support the concept that portal LPS delivery is important in the hepatic response to surgical attenuation. Serum IL-6 significantly increased following surgery, consistent with LPS stimulation via TLR4, although this increase might be non-specific. Copyright © 2015 Elsevier Ltd. All rights reserved.

  18. Toll-Like Receptor-3 and Geographic Atrophy in Age-Related Macular Degeneration

    PubMed Central

    Yang, Zhenglin; Stratton, Charity; Francis, Peter J.; Kleinman, Mark E.; Tan, Perciliz L.; Gibbs, Daniel; Tong, Zongzhong; Chen, Haoyu; Constantine, Ryan; Yang, Xian; Chen, Yuhong; Zeng, Jiexi; Davey, Lisa; Ma, Xiang; Hau, Vincent S.; Wang, Chi; Harmon, Jennifer; Buehler, Jeanette; Pearson, Erik; Patel, Shrena; Kaminoh, Yuuki; Watkins, Scott; Luo, Ling; Zabriskie, Norman A.; Bernstein, Paul S.; Cho, Wongil; Schwager, Andrea; Hinton, David R; Klein, Michael L; Hamon, Sara C.; Simmons, Emily; Yu, Beifeng; Campochiaro, Betsy; Sunness, Janet S.; Campochiaro, Peter; Jorde, Lynn; Parmigiani, Giovanni; Zack, Donald J.; Katsanis, Nicholas; Ambati, Jayakrishna; Zhang, Kang

    2008-01-01

    BACKGROUND Age-related macular degeneration (AMD) is the most common cause of irreversible visual impairment in the developed world. Advanced AMD is comprised of geographic atrophy (GA) and choroidal neovascularization (CNV). Specific genetic variants that predispose for GA are largely unknown. METHODS We tested (i) for association between the functional toll-like receptor-3 (TLR3) variant rs3775291 (L412F) and AMD in European Americans and (ii) the effect of TLR3 L and F variants on the viability of human retinal pigment epithelium (RPE) cells in vitro and on RPE cell apoptosis in wildtype and Tlr3−/− mice. RESULTS The F variant (or T allele at single nucleotide polymorphism at rs3775291) was associated with protection against GA (P=0.005); this association was replicated in two independent GA case-control series (P=5.43×10−4 and P=0.002, respectively. We observed no association between TLR3 variants and CNV. The rs377291 variant is probably critical to the function of TLR3, because a prototypic TLR3 ligand induced cell death and apoptosis in human RPE cells with the LL genotype to a greater extent than it did RPE cells with the LF genotype. Moreover, the ligand induced more RPE cell death and apoptosis in wild-type than in Tlr3−/− mice. CONCLUSIONS The TLR3 412F variant confers protection against GA, probably by suppressing RPE cell death. Given that double stranded RNA can activate TLR3-mediated apoptosis, our results suggest a possible role for viral dsRNA transcripts in the development of GA and raise awareness of potential toxicity induced by short interfering RNA (siRNA) therapeutics in the eye. PMID:18753640

  19. Accelerated model of lupus autoimmunity and vasculopathy driven by toll-like receptor 7/9 imbalance.

    PubMed

    Liu, Yudong; Seto, Nickie L; Carmona-Rivera, Carmelo; Kaplan, Mariana J

    2018-01-01

    Activation of endosomal toll-like receptor (TLR)7 or TLR9 has been proposed as a critical step for the initiation and development of SLE. Traditional spontaneous lupus models normally introduce multiple risk alleles, thereby adding additional confounding factors. In the induced lupus models, the role of TLR9 remains unclear. In the present study, we explored the role of an imbalance between TLR7 and TLR9 pathways in the pathogenesis of lupus and its associated vasculopathy using the imiquimod model in TLR9 KO/B6 background. Wild type (WT) and Tlr9 -/- mice were epicutaneously treated with imiquimod cream 5% on both ears three times per week for indicated times. At euthanasia, mice were analysed for organ involvement, endothelium-dependent vasorelaxation, serum autoantibodies, and innate and adaptive immune responses. Compared with the lupus-like phenotype that develops in imiquimod-treated WT mice, Tlr9 -/- mice exposed to imiquimod have increased severity of autoimmunity features and inflammatory phenotype that develops at earlier stages. These abnormalities are characterised by enhanced TLR7 expression and immune activation, increased immune complex deposition, Th1 T cells and dendritic cell kidney infiltration and significant impairments in endothelial function. Modulation of TLR7 expression was observed in the Tlr9 -/- mice. These findings further underscore the protective role of TLR9 in TLR7-driven autoimmunity and also in the development of vasculopathy, further strengthening the importance of tightly manipulating TLRs in putative therapeutic strategies. This study provides a new model of accelerated lupus phenotype driven by danger-associated molecular patterns.

  20. Characterization and functional analysis of toll-like receptor 4 in Chinese soft-shelled turtle Pelodiscus sinensis.

    PubMed

    Zhou, Yingshan; Liang, Quan; Li, Weifen; Gu, Yuanxing; Liao, Xun; Fang, Weihuan; Li, Xiaoliang

    2016-10-01

    Mammalian Toll-like receptor 4 (TLR4) recognizes lipopolysaccharide (LPS) in initiating the innate immune responses. Early studies indicate that turtles are more resistant to LPS challenge than mammals. It remains unknown if turtles express TLR4 and why they are more resistant to LPS. In this study, TLR4 gene from Chinese soft-shelled turtle, Pelodiscus sinensis, was cloned and characterized. The full length cDNA of turtle TLR4 (tTLR4) consists of 3396 base pairs with an 2499-bp open reading frame, encoding 833 amino acids. Phylogenetic and syntenic analyses suggest that tTLR4 is to be orthologous to human TLR4. Its mRNA expression was up-regulated in spleen and blood of turtles upon Aeromonas hydrophila infection. Stimulation of turtle peripheral blood monocytes with LPS significantly upregulated tTLR4 mRNA and inflammation-related gene expression, such as Interleukin-1β (IL-1β) and cyclooxygenase-2 (COX-2). In tTLR4-expressing HEK293 cells, higher concentration of LPS exposure could enhance the activity of the NF-κB promoter, but not the INF-β promoter. Such activity required co-expression of turtle myeloid differentiation factor 2 (tMD2) and cluster of differentiation 14 (tCD14). These results provide evidence for a functional TLR4 in reptiles and, together with the syntenic analysis, support the idea that the TLR4 receptor for LPS recognition may have arisen after reptiles. Copyright © 2016 Elsevier Ltd. All rights reserved.

  1. IRAK4 kinase activity controls Toll-like receptor-induced inflammation through the transcription factor IRF5 in primary human monocytes.

    PubMed

    Cushing, Leah; Winkler, Aaron; Jelinsky, Scott A; Lee, Katherine; Korver, Wouter; Hawtin, Rachael; Rao, Vikram R; Fleming, Margaret; Lin, Lih-Ling

    2017-11-10

    Interleukin-1 receptor-associated kinase 4 (IRAK4) plays a critical role in innate immune signaling by Toll-like receptors (TLRs), and loss of IRAK4 activity in mice and humans increases susceptibility to bacterial infections and causes defects in TLR and IL1 ligand sensing. However, the mechanism by which IRAK4 activity regulates the production of downstream inflammatory cytokines is unclear. Using transcriptomic and biochemical analyses of human monocytes treated with a highly potent and selective inhibitor of IRAK4, we show that IRAK4 kinase activity controls the activation of interferon regulatory factor 5 (IRF5), a transcription factor implicated in the pathogenesis of multiple autoimmune diseases. Following TLR7/8 stimulation by its agonist R848, chemical inhibition of IRAK4 abolished IRF5 translocation to the nucleus and thus prevented IRF5 binding to and activation of the promoters of inflammatory cytokines in human monocytes. We also found that IKKβ, an upstream IRF5 activator, is phosphorylated in response to the agonist-induced TLR signaling. Of note, IRAK4 inhibition blocked IKKβ phosphorylation but did not block the nuclear translocation of NFκB, which was surprising, given the canonical role of IKKβ in phosphorylating IκB to allow NFκB activation. Moreover, pharmacological inhibition of either IKKβ or the serine/threonine protein kinase TAK1 in monocytes blocked TLR-induced cytokine production and IRF5 translocation to the nucleus, but not nuclear translocation of NFκB. Taken together, our data suggest a mechanism by which IRAK4 activity regulates TAK1 and IKKβ activation, leading to the nuclear translocation of IRF5 and induction of inflammatory cytokines in human monocytes. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  2. Trichoderma G protein-coupled receptors: functional characterisation of a cAMP receptor-like protein from Trichoderma atroviride.

    PubMed

    Brunner, Kurt; Omann, Markus; Pucher, Marion E; Delic, Marizela; Lehner, Sylvia M; Domnanich, Patrick; Kratochwill, Klaus; Druzhinina, Irina; Denk, Dagmar; Zeilinger, Susanne

    2008-12-01

    Galpha subunits act to regulate vegetative growth, conidiation, and the mycoparasitic response in Trichoderma atroviride. To extend our knowledge on G protein signalling, we analysed G protein-coupled receptors (GPCRs). As the genome sequence of T. atroviride is not publicly available yet, we carried out an in silico exploration of the genome database of the close relative T. reesei. Twenty genes encoding putative GPCRs distributed over eight classes and additional 35 proteins similar to the Magnaporthe grisea PTH11 receptor were identified. Subsequently, four T. atroviride GPCR-encoding genes were isolated and affiliated to the cAMP receptor-like family by phylogenetic and topological analyses. All four genes showed lowest expression on glycerol and highest mRNA levels upon carbon starvation. Transcription of gpr3 and gpr4 responded to exogenously added cAMP and the shift from liquid to solid media. gpr3 mRNA levels also responded to the presence of fungal hyphae or cellulose membranes. Further characterisation of mutants bearing a gpr1-silencing construct revealed that Gpr1 is essential for vegetative growth, conidiation and conidial germination. Four genes encoding the first GPCRs described in Trichoderma were isolated and their expression characterized. At least one of these GPCRs is important for several cellular processes, supporting the fundamental role of G protein signalling in this fungus.

  3. Longitudinal expression of Toll-like receptors on dendritic cells in uncomplicated pregnancy and postpartum

    PubMed Central

    Young, Brett C.; Stanic, Aleksandar K.; Panda, Britta; Rueda, Bo R.; Panda, Alexander

    2014-01-01

    OBJECTIVE Toll-like receptors (TLRs) are integral parts of the innate immune system and have been implicated in complications of pregnancy. The longitudinal expression of TLRs on dendritic cells in the maternal circulation during uncomplicated pregnancies is unknown. The objective of this study was to prospectively evaluate TLRs 1-9 as expressed on dendritic cells in the maternal circulation at defined intervals throughout pregnancy and postpartum. STUDY DESIGN This was a prospective cohort of 30 pregnant women with uncomplicated pregnancies and 30 nonpregnant controls. TLRs and cytokine expression was measured in unstimulated dendritic cells at 4 defined intervals during pregnancy and postpartum. Basal expression of TLRs and cytokines was measured by multicolor flow cytometry. The percent-positive dendritic cells for each TLRs were compared with both nonpregnant and postpartum levels with multivariate linear regression. RESULTS TLRs 1, 7, and 9 were elevated compared with nonpregnant controls with persistent elevation of TLR 1 and interleukin-12 (IL-12) into the postpartum period. Concordantly, levels of IL-6, IL-12, interferon alpha, and tumor necrosis factor alpha increased during pregnancy and returned to levels similar to nonpregnant controls during the postpartum period. The elevated levels of TLR 1 and IL-12 were persistent postpartum, challenging notions that immunologic changes during pregnancy resolve after the prototypical postpartum period. CONCLUSION Normal pregnancy is associated with time-dependent changes in TLR expression compared with nonpregnant controls; these findings may help elucidate immunologic dysfunction in complicated pregnancies. PMID:24291497

  4. Toll-Like Receptor–2/6 and Toll-Like Receptor–9 Agonists Suppress Viral Replication but Not Airway Hyperreactivity in Guinea Pigs

    PubMed Central

    Evans, Scott E.; Dickey, Burton F.; Fryer, Allison D.; Jacoby, David B.

    2013-01-01

    Respiratory virus infections cause airway hyperreactivity (AHR). Preventative strategies for virus-induced AHR remain limited. Toll-like receptors (TLRs) have been suggested as a therapeutic target because of their central role in triggering antiviral immune responses. Previous studies showed that concurrent treatment with TLR2/6 and TLR9 agonists reduced lethality and the microbial burden in murine models of bacterial and viral pneumonia. This study investigated the effects of TLR2/6 and TLR9 agonist pretreatment on parainfluenza virus pneumonia and virus-induced AHR in guinea pigs in vivo. Synthetic TLR2/6 lipopeptide agonist Pam2CSK4 and Class C oligodeoxynucleotide TLR9 agonist ODN2395, administered in combination 24 hours before virus infection, significantly reduced viral replication in the lung. Despite a fivefold reduction in viral titers, concurrent TLR2/6 and TLR9 agonist pretreatment did not prevent virus-induced AHR or virus-induced inhibitory M2 muscarinic receptor dysfunction. Interestingly, the TLR agonists independently caused non–M2-dependent AHR. These data confirm the therapeutic antiviral potential of TLR agonists, while suggesting that virus inhibition may be insufficient to prevent virus-induced airway pathophysiology. Furthermore, TLR agonists independently cause AHR, albeit through a distinctly different mechanism from that of parainfluenza virus. PMID:23449736

  5. The Potential Role of Toll-Like Receptor 4 in Mediating Dopaminergic Cell Loss and Alpha-Synuclein Expression in the Acute MPTP Mouse Model of Parkinson's Disease.

    PubMed

    Mariucci, Giuseppina; Pagiotti, Rita; Galli, Francesco; Romani, Luigina; Conte, Carmela

    2018-04-01

    Toll-like receptors (TLRs) may have a role in Parkinson's disease (PD). In this study, we aimed at investigating the dopaminergic cell loss and alpha-synuclein (α-SYN) expression in TLR4-deficient mice (TLR4 -/- ) acutely exposed to 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), a pharmacological PD model. TLR4 ablation restrained the number of dopaminergic neurons in the substantia nigra (SN), as assessed by tyrosine hydroxylase (TH) protein expression. Intriguingly, TLR4 -/- mice showed massive α-SYN protein accumulation in the midbrain along with high α-SYN mRNA levels in cerebral cortex, striatum, hippocampus, and cerebellum. Contrary to expectations, the high levels of α-SYN do not correlate with greater dopaminergic neuronal loss. The levels of nigral α-SYN protein in TLR4 -/- mice further, but not significantly, increased during MPTP treatment. Contrariwise, MPTP treatment significantly induced the mRNA expression of α-SYN in examined brain regions of WT and TLR4 -/- mice. Protein levels of GATA2, a transcription factor proposed to control α-SYN gene expression, did not change in TLR4 -/- mice at baseline and after MPTP treatment. These findings suggest a role for TLR4 in mediating dopaminergic cell loss and in the constitutive expression of brain α-SYN. However, further exploration is needed in order to establish the actual role of α-SYN in the relative absence of TLR4.

  6. Naloxone inhibits nod-like receptor protein 3 inflammasome.

    PubMed

    Lin, Han-Yu; Chang, Ya-Ying; Kao, Ming-Chang; Huang, Chun-Jen

    2017-11-01

    Naloxone, an opioid receptor antagonist, possesses potent anti-inflammation effects. We previously confirmed the effects of naloxone on inhibiting upregulation of inflammatory cytokine interleukin-1β (IL-1β). Production of mature form IL-1β is mediated by the nod-like receptor protein 3 (NLRP3) inflammasome, a multiprotein complex composed of NLRP3, and the adaptor protein apoptosis-associated speck-like protein contains a caspase recruitment domain (ASC). We elucidated whether naloxone could inhibit the activation of NLRP3 inflammasome. To induce IL-1β production and NLRP3 inflammasome activation, the human monocytic leukemia cell line THP-1 cells were first primed with lipopolysaccharide (LPS, 1 μg/mL) and then activated with adenosine triphosphate (ATP, 1 mM). For NLRP3 transcription, THP-1 cells were only treated with LPS priming. Enzyme-link immunosorbent assay data revealed that the concentration of IL-1β in THP-1 cells treated with LPS plus ATP was significantly higher than that in THP-1 cells treated with LPS plus ATP plus naloxone (0.1 μM) (P < 0.001). Real-time quantitative reverse transcription and polymerase chain reaction data also revealed that NLRP3 mRNA concentration in THP-1 cells treated with LPS was significantly higher than that in THP-1 cells treated with LPS plus naloxone (P = 0.001). ASC speck formation, that is, ASC assembles into a large protein complex, is an indicator for NLRP3 inflammasome activation. Our data revealed that the percentage of cells containing ASC specks in THP-1 cells treated with LPS plus ATP was also significantly higher than that in THP-1 cells treated with LPS plus ATP plus naloxone (P < 0.001). Naloxone inhibits NLRP3 inflammasome activation. Copyright © 2017 Elsevier Inc. All rights reserved.

  7. Serine Lipids of Porphyromonas gingivalis Are Human and Mouse Toll-Like Receptor 2 Ligands

    PubMed Central

    Clark, Robert B.; Cervantes, Jorge L.; Maciejewski, Mark W.; Farrokhi, Vahid; Nemati, Reza; Yao, Xudong; Anstadt, Emily; Fujiwara, Mai; Wright, Kyle T.; Riddle, Caroline; La Vake, Carson J.; Salazar, Juan C.; Finegold, Sydney

    2013-01-01

    The total cellular lipids of Porphyromas gingivalis, a known periodontal pathogen, were previously shown to promote dendritic cell activation and inhibition of osteoblasts through engagement of Toll-like receptor 2 (TLR2). The purpose of the present investigation was to fractionate all lipids of P. gingivalis and define which lipid classes account for the TLR2 engagement, based on both in vitro human cell assays and in vivo studies in mice. Specific serine-containing lipids of P. gingivalis, called lipid 654 and lipid 430, were identified in specific high-performance liquid chromatography fractions as the TLR2-activating lipids. The structures of these lipids were defined using tandem mass spectrometry and nuclear magnetic resonance methods. In vitro, both lipid 654 and lipid 430 activated TLR2-expressing HEK cells, and this activation was inhibited by anti-TLR2 antibody. In contrast, TLR4-expressing HEK cells failed to be activated by either lipid 654 or lipid 430. Wild-type (WT) or TLR2-deficient (TLR2−/−) mice were injected with either lipid 654 or lipid 430, and the effects on serum levels of the chemokine CCL2 were measured 4 h later. Administration of either lipid 654 or lipid 430 to WT mice resulted in a significant increase in serum CCL2 levels; in contrast, the administration of lipid 654 or lipid 430 to TLR2−/− mice resulted in no increase in serum CCL2. These results thus identify a new class of TLR2 ligands that are produced by P. gingivalis that likely play a significant role in mediating inflammatory responses both at periodontal sites and, potentially, in other tissues where these lipids might accumulate. PMID:23836823

  8. Transcriptome-wide identification, molecular evolution and expression analysis of Toll-like receptor family in a Tibet fish, Gymnocypris przewalskii.

    PubMed

    Tong, Chao; Lin, Yaqiu; Zhang, Cunfang; Shi, Jianquan; Qi, Hongfang; Zhao, Kai

    2015-10-01

    Toll-like receptors (TLR) are key components of innate immunity that play significant roles in immune defense against pathogens invasion. Recent frequent outbreaks of the "white spot disease" caused by parasitic infection in farmed Tibetan fishes had resulted in great economic losses. However, to our knowledge, the roles of TLRs in mediating immune response to parasitic infection in Tibetan fishes remain to be determined. Here, we performed data-mining on a widely-farmed Tibetan fish (Gymnocypris przewalskii or Gp) transcriptome to determine the genetic variation and expression pattern of TLRs. We totally obtained 14 GpTLRs and identified 5 with a complete coding sequence. Phylogenetic analysis verified their identities and supported the classification of TLRs into six families as in other vertebrates. The TLR family motifs, such as leucine rich repeat (LRR) and Toll/interleukin (IL)-1 receptor (TIR) domain, are conserved in GpTLR1-5. Selective pressure test demonstrated that all known GpTLRs are under purifying selection, except GpTLR4 underwent positive selection. Further, site model analysis suggested that 11 positively selected sites are found in LRR domain of GpTLR4. Three positively selected sites are located on outside surface of TLR4 3D structure, indicating that function of GpTLR4 may be affected. Tissue specific expression analysis showed all GpTLRs are present in gill, head-kidney and spleen but the relative abundance varied among tissues. In response to parasite Ichthyophthirius multifiliis infection, 5 GpTLR (GpTLR1, -2, -4, -9 and -20) expressions were induced. Intriguingly, GpTLR4 was significantly up-regulated in gills, while GpTLR19 and GpTLR21 unexpectedly showed no any change. In summary, these results revealed the first genomic resources of TLR family and several parasitic infection responsive TLRs in Tibetan fish. These findings provide key information for future studies aiming to understand the molecular mechanisms underlying the immune

  9. Differential induction of Toll-like receptors & type 1 interferons by Sabin attenuated & wild type 1 polioviruses in human neuronal cells.

    PubMed

    Mohanty, Madhu C; Deshpande, Jagadish M

    2013-01-01

    Polioviruses are the causative agent of paralytic poliomyelitis. Attenuated polioviruses (Sabin oral poliovirus vaccine strains) do not replicate efficiently in neurons as compared to the wild type polioviruses and therefore do not cause disease. This study was aimed to investigate the differential host immune response to wild type 1 poliovirus (wild PV) and Sabin attenuated type 1 poliovirus (Sabin PV) in cultured human neuronal cells. By using flow cytometry and real time PCR methods we examined host innate immune responses and compared the role of toll like receptors (TLRs) and cytoplasmic RNA helicases in cultured human neuronal cells (SK-N-SH) infected with Sabin PV and wild PV. Human neuronal cells expressed very low levels of TLRs constitutively. Sabin PV infection induced significantly higher expression of TLR3, TLR7 and melanoma differentiation-associated protein-5 (MDA-5) m-RNA in neuronal cells at the beginning of infection (up to 4 h) as compared to wild PV. Further, Sabin PV also induced the expression of interferon α/β at early time point of infection. The induced expression of IFN α/β gene by Sabin PV in neuronal cells could be suppressed by inhibiting TLR7. Neuronal cell innate immune response to Sabin and wild polioviruses differ significantly for TLR3, TLR7, MDA5 and type 1 interferons. Effects of TLR7 activation and interferon production and Sabin virus replication in neuronal cells need to be actively investigated in future studies.

  10. Variants in toll-like receptor 9 gene influence susceptibility to tuberculosis in a Mexican population

    PubMed Central

    2013-01-01

    Background The control of Mycobacterium tuberculosis (Mtb) infection begins with the recognition of mycobacterial structural components by toll like receptors (TLRs) and other pattern recognition receptors. Our objective was to determine the influence of TLRs polymorphisms in the susceptibility to develop tuberculosis (TB) in Amerindian individuals from a rural area of Oaxaca, Mexico with high TB incidence. Methods We carried out a case–control association community based study, genotyping 12 polymorphisms of TLR2, TLR4, TLR6 and TLR9 genes in 90 patients with confirmed pulmonary TB and 90 unrelated exposed but asymptomatic household contacts. Results We found a significant increase in the frequency of the allele A of the TLR9 gene polymorphism rs352139 (A>G) in the group of TB patients (g.f. = 0.522) when compared with controls (g.f. = 0.383), (Pcorr = 0.01, OR = 1.75). Under the recessive model (A/G + A/A vs G/G) this polymorphism was also significantly associated with TB (Pcorr = 0.01, OR= 2.37). The association of the SNP rs352139 was statistically significant after adjustment by age, gender and comorbidities by regression logistic analysis (Dominant model: p value = 0.016, OR = 2.31; Additive model: p value = 0.023, OR = 1.68). The haplotype GAA of TLR9 SNPs was also associated with TB susceptibility (Pcorr = 0.02). Differences in the genotype or allele frequencies of TLR2, TLR4 and TLR6 polymorphisms between TB patients and healthy contacts were not detected. Conclusions Our study suggests that the allele A of the intronic polymorphism rs352139 on TLR9 gene might contribute to the risk of developing TB in Mexican Amerindians. PMID:24053111

  11. Toll-like receptor 5 in obesity: the role of gut microbiota and adipose tissue inflammation.

    PubMed

    Pekkala, Satu; Munukka, Eveliina; Kong, Lingjia; Pöllänen, Eija; Autio, Reija; Roos, Christophe; Wiklund, Petri; Fischer-Posovszky, Pamela; Wabitsch, Martin; Alen, Markku; Huovinen, Pentti; Cheng, Sulin

    2015-03-01

    This study aimed at establishing bacterial flagellin-recognizing toll-like receptor 5 (TLR5) as a novel link between gut microbiota composition, adipose tissue inflammation, and obesity. An adipose tissue microarray database was used to compare women having the highest (n = 4, H-TLR) and lowest (n = 4, L-TLR) expression levels of TLR5-signaling pathway genes. Gut microbiota composition was profiled using flow cytometry and FISH. Standard laboratory techniques were used to determine anthropometric and clinical variables. In vivo results were verified using cultured human adipocytes. The H-TLR group had higher flagellated Clostridium cluster XIV abundance and Firmicutes-to-Bacteroides ratio. H-TLR subjects had obese phenotype characterized by greater waist circumference, fat %, and blood pressure (P < 0.05 for all). They also had higher leptin and lower adiponectin levels (P < 0.05 for both). Six hundred and sixty-eight metabolism- and inflammation-related adipose tissue genes were differentially expressed between the groups. In vitro studies confirmed that flagellin activated TLR5 inflammatory pathways, decreased insulin signaling, and increased glycerol secretion. The in vivo findings suggest that flagellated Clostridium cluster XIV bacteria contribute to the development of obesity through distorted adipose tissue metabolism and inflammation. The in vitro studies in adipocytes show that the underlying mechanisms of the human findings may be due to flagellin-activated TLR5 signaling. © 2015 The Obesity Society.

  12. Acute high-intensity interval exercise reduces human monocyte Toll-like receptor 2 expression in type 2 diabetes.

    PubMed

    Durrer, Cody; Francois, Monique; Neudorf, Helena; Little, Jonathan P

    2017-04-01

    Type 2 diabetes (T2D) is characterized by chronic low-grade inflammation that contributes to disease pathophysiology. Exercise has anti-inflammatory effects, but the impact of high-intensity interval training (HIIT) is not known. The purpose of this study was to determine the impact of a single session of HIIT on cellular, molecular, and circulating markers of inflammation in individuals with T2D. Participants with T2D ( n = 10) and healthy age-matched controls (HC; n = 9) completed an acute bout of HIIT (7 × 1 min at ~85% maximal aerobic power output, separated by 1 min of recovery) on a cycle ergometer with blood samples obtained before (Pre), immediately after (Post), and at 1 h of recovery (1-h Post). Inflammatory markers on leukocytes were measured by flow cytometry, and TNF-α was assessed in both LPS-stimulated whole blood cultures and plasma. A single session of HIIT had an overall anti-inflammatory effect, as evidenced by 1 ) significantly lower levels of Toll-like receptor (TLR) 2 surface protein expression on both classical and CD16+ monocytes assessed at Post and 1-h Post compared with Pre ( P < 0.05 for all); 2 ) significantly lower LPS-stimulated TNF-α release in whole blood cultures at 1-h Post ( P < 0.05 vs. Pre); and 3 ) significantly lower levels of plasma TNF-α at 1-h Post ( P < 0.05 vs. Pre). There were no differences between T2D and HC, except for a larger decrease in plasma TNF-α in HC vs. T2D (group × time interaction, P < 0.05). One session of low-volume HIIT has immunomodulatory effects and provides potential anti-inflammatory benefits to people with, and without, T2D. Copyright © 2017 the American Physiological Society.

  13. Streptococcus gordonii induces nitric oxide production through its lipoproteins stimulating Toll-like receptor 2 in murine macrophages.

    PubMed

    Kim, Hyun Young; Baik, Jung Eun; Ahn, Ki Bum; Seo, Ho Seong; Yun, Cheol-Heui; Han, Seung Hyun

    2017-02-01

    Streptococcus gordonii, a Gram-positive commensal in the oral cavity, is an opportunistic pathogen that can cause endodontic and systemic infections resulting in infective endocarditis. Lipoteichoic acid (LTA) and lipoprotein are major virulence factors of Gram-positive bacteria that are preferentially recognized by Toll-like receptor 2 (TLR2) on immune cells. In the present study, we investigated the effect of S. gordonii LTA and lipoprotein on the production of the representative inflammatory mediator nitric oxide (NO) by the mouse macrophages. Heat-killed S. gordonii wild-type and an LTA-deficient mutant (ΔltaS) but not a lipoprotein-deficient mutant (Δlgt) induced NO production in mouse primary macrophages and the cell line, RAW 264.7. S. gordonii wild-type and ΔltaS also induced the expression of inducible NO synthase (iNOS) at the mRNA and protein levels. In contrast, the Δlgt mutant showed little effect under the same condition. Furthermore, S. gordonii wild-type and ΔltaS induced NF-κB activation, STAT1 phosphorylation, and IFN-β expression, which are important for the induction of iNOS gene expression, with little activation by Δlgt. S. gordonii wild-type and ΔltaS showed an increased adherence and internalization to RAW 264.7 cells compared to Δlgt. In addition, S. gordonii wild-type and ΔltaS, but not Δlgt, substantially increased TLR2 activation while none of these induced NO production in TLR2-deficient macrophages. Triton X-114-extracted lipoproteins from S. gordonii were sufficient to induce NO production. Collectively, we suggest that lipoprotein is an essential cell wall component of S. gordonii to induce NO production in macrophages through TLR2 triggering NF-κB and STAT1 activation. Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. Acute high-intensity interval exercise reduces human monocyte Toll-like receptor 2 expression in type 2 diabetes

    PubMed Central

    Durrer, Cody; Francois, Monique; Neudorf, Helena

    2017-01-01

    Type 2 diabetes (T2D) is characterized by chronic low-grade inflammation that contributes to disease pathophysiology. Exercise has anti-inflammatory effects, but the impact of high-intensity interval training (HIIT) is not known. The purpose of this study was to determine the impact of a single session of HIIT on cellular, molecular, and circulating markers of inflammation in individuals with T2D. Participants with T2D (n = 10) and healthy age-matched controls (HC; n = 9) completed an acute bout of HIIT (7 × 1 min at ~85% maximal aerobic power output, separated by 1 min of recovery) on a cycle ergometer with blood samples obtained before (Pre), immediately after (Post), and at 1 h of recovery (1-h Post). Inflammatory markers on leukocytes were measured by flow cytometry, and TNF-α was assessed in both LPS-stimulated whole blood cultures and plasma. A single session of HIIT had an overall anti-inflammatory effect, as evidenced by 1) significantly lower levels of Toll-like receptor (TLR) 2 surface protein expression on both classical and CD16+ monocytes assessed at Post and 1-h Post compared with Pre (P < 0.05 for all); 2) significantly lower LPS-stimulated TNF-α release in whole blood cultures at 1-h Post (P < 0.05 vs. Pre); and 3) significantly lower levels of plasma TNF-α at 1-h Post (P < 0.05 vs. Pre). There were no differences between T2D and HC, except for a larger decrease in plasma TNF-α in HC vs. T2D (group × time interaction, P < 0.05). One session of low-volume HIIT has immunomodulatory effects and provides potential anti-inflammatory benefits to people with, and without, T2D. PMID:28122717

  15. Readressing the role of Toll-like receptor-4 alleles in inflammatory bowel disease: colitis, smoking, and seroreactivity.

    PubMed

    Manolakis, Anastassios C; Kapsoritakis, Andreas N; Kapsoritaki, Anastasia; Tiaka, Elisavet K; Oikonomou, Konstantinos A; Lotis, Vassilis; Vamvakopoulou, Dimitra; Davidi, Ioanna; Vamvakopoulos, Nikolaos; Potamianos, Spyros P

    2013-02-01

    Toll-like receptor (TLR) polymorphisms, and especially TLR-4 Asp299Gly and TLR-4 Thr399Ile, have been linked with Crohn's disease (CD) and to a lesser extent with ulcerative colitis (UC), CD behavior, and compromised seroreactivity to microbial antigens. Available data, however, are conflicting. To address these issues, the distribution of TLR-4 polymorphic alleles was assessed in patients with UC, CD, and healthy controls (HC), considering patient and disease characteristics as well as related serological markers. TLR-4 Asp299Gly and TLR-4 Thr399Ile polymorphisms were determined in 187 UC and 163 CD patients and 274 randomly selected HC. C reactive protein, anti-Saccharomyces cerevisiae mannan antibodies, anti-mannobioside carbohydrate antibodies, anti-laminariobioside carbohydrate antibodies IgG, and anti-chitobioside carbohydrate antibodies (ACCA) IgA levels were also assessed. UC and especially pancolitis patients carried the mutant alleles more frequently compared to CD patients and HC or UC patients with different disease extents (P = 0.002 and P < 0.0001, respectively). Involvement of the colon was more frequent in CD patients with mutant TLR-4 compared to those with wild-type alleles (P = 0.004). Levels and positivity rates of ACCA IgA were lower in inflammatory bowel disease (IBD) patients carrying the mutant compared to those with wild-type alleles (0.075 < P < 0.05). Despite the mutant TLR-4 predisposition for UC pancolitis, smoking was associated with more limited disease (P < 0.001). The presence of TLR-4 Asp299Gly and TLR-4 Thr399Ile polymorphisms is related to UC pancolitis, involvement of the colon in CD, and lower ACCA IgA levels. Smoking reduces the extent of UC, even in the presence of mutant alleles.

  16. Cloning and characterisation of the SpToll gene from green mud crab, Scylla paramamosain.

    PubMed

    Lin, Zhongyang; Qiao, Jie; Zhang, Yueling; Guo, Lingling; Huang, He; Yan, Fang; Li, Yuanyou; Wang, Xiuying

    2012-05-01

    Toll/Toll-like receptors (TLRs), one of the most important pattern recognition receptors (PRRs), play a crucial role in innate immune responses in both invertebrates and vertebrates. In this study, we cloned and characterised a Toll gene from Scylla paramamosain (SpToll). Bioinformatic analysis predicted that SpToll contained one open reading frame of 3018bp and encoded a single-pass transmembrane domain protein of 1005 amino acids. Further, SpToll could be clustered into one branch along with other arthropod Tolls in a phylogenetic tree. SpToll transcripts could be detected by RT-PCR from all tissues examined including the heart, gill, hepatopancreas, stomach, intestine, muscle, eyestalk and hemocytes. Infection by Vibrio parahemolyticus up-regulated SpToll mRNA expression in hemocytes after 48h. The profile of single nucleotide polymorphisms (SNPs) in the leucine-rich repeats (LRRs) domain of SpToll in three healthy crabs was then evaluated. Two hundred and twenty SNPs with a frequency of about 1.0-4.0% were identified in hemocyte DNA/cDNA. Surprisingly, the adenine to guanine transition at position 1372 (c.1372A>G) had a frequency of about 50%. Finally, the results showed that challenge with V. parahemolyticus stimulated the appearance of two sets of SNPs in crabs. More importantly, the c.1372A>G mutation could contribute to a low mortality after V. parahemolyticus infection and introduce variation of charge and secondary structure into the SpToll polypeptide. In summary, these studies suggested a novel Toll homologue in crab and identified a SNP with potential pathogen-resistant activities. The result will be important for the investigation of crab immune defense mechanisms. Copyright © 2011 Elsevier Ltd. All rights reserved.

  17. Interleukin 17A and Toll-like Receptor 4 in Patients with Arterial Hypertension.

    PubMed

    Simundic, Tihana; Jelakovic, Bojan; Dzumhur, Andrea; Turk, Tajana; Sahinovic, Ines; Dobrosevic, Blazenka; Takac, Boris; Barbic, Jerko

    2017-01-01

    Immune responses are involved in arterial hypertension. An observational cross-sectional case control study was conducted to estimate the association between Toll-like receptor 4 (TLR4) expression and interleukin (IL)-17A serum levels in patients with controlled and non-controlled hypertension. We have enrolled 105 non-complicated otherwise healthy hypertensive patients: 53 with well-controlled blood pressure and 52 non-controlled. TLR4 peripheral monocytes expression and serum IL-17A levels were determined by flow cytometry and ELISA, respectively. Non-controlled patients exhibited higher TLR4 expression than well-controlled (25.60 vs. 21.99, P=0.011). TLR4 expression was lower in well-controlled patients who were prescribed beta blockers (18.9 vs. 22.6, P=0.005) and IL-17A concentration was higher in patients using diuretics in either group (1.41 vs. 2.01 pg/ml, P<0.001; well-controlled 1.3 vs. 1.8 pg/ml, P= 0.023; non-controlled 1.6 vs. 2.3 pg/ml, P=0.001). Correlation between IL-17A concentration and hypertension duration was observed in non-controlled patients (Spearman correlation coefficient . ρ=0.566, P<0.001) whereas in well-controlled patients a correlation was found between hypertension duration and TLR4 expression (ρ=0.322, P=0.020). Arterial hypertension stimulates the immune response regardless of blood pressure regulation status. Prolonged hypertension influences peripheral monocyte TLR4 expression and IL-17A serum levels. Anti-hypertensive drugs have different immunomodulatory effects: diuretics are associated with higher IL-17A concentration and beta-blockers with lower TLR4 expression. © 2017 The Author(s)Published by S. Karger AG, Basel.

  18. Toll-like Receptor 1 743 A>G, 1805 T>G & Toll-like Receptor 6 745 C>T gene polymorphism and tuberculosis: a case control study of north Indian population from Agra (India).

    PubMed

    Sinha, Ekata; Biswas, Sanjay K; Mittal, Mayank; Bajaj, Bharat; Singh, Vandana; Arela, Nidhi; Katoch, Vishwa M; Mohanty, Keshar Kunja

    2014-08-01

    Infection with Mycobacteriumtuberculosis possibly depends on host genetic factors and is thought to be the major cause of differential susceptibility to the disease. In the present study, 205 pulmonary tuberculosis cases and 127 healthy controls were studied for the association of Toll-like Receptor (TLR) variants (TLR1 variants 743A>G and 1805T>G, and TLR6 variant 745 C>T) in north Indian population. The frequency of heterozygous genotypes (AG) in TB cases (0.47) and HCs (0.61), differed significantly (p value = 0.02). The association of AG genotypes in HCs was adjusted for gender as gender was observed to be a confounder and M-H OR was found to be 0.62 (p = 0.044). On categorizing the cases basing on AFB smear positivity, the heterozygous genotypes (AG) was found to be associated with low bacillary load (scanty and 1+) (P = 0.002). No association was observed for either TLR1 1805 T>G or TLR6 745 C>T polymorphism. Level of serum IL6 was found to be significantly higher among healthy controls with TLR1 GG genotype compared to healthy controls with AA (p = 0.035) and AG (p = 0.005) genotypes. Thus, it may be suggested that the heterozygous condition for TLR1 743 A>G provide resistance from the disease. However, in depth study is required to understand the mechanism for possible protective responses. Copyright © 2014 American Society for Histocompatibility and Immunogenetics. Published by Elsevier Inc. All rights reserved.

  19. Src is required for migration, phagocytosis, and interferon beta production in Toll-like receptor-engaged macrophages.

    PubMed

    Maa, Ming-Chei; Leu, Tzeng-Horng

    2016-06-01

    As an evolutionarily conserved mechanism, innate immunity controls self-nonself discrimination to protect a host from invasive pathogens. Macrophages are major participants of the innate immune system. Through the activation of diverse Toll-like receptors (TLRs), macrophages are triggered to initiate a variety of functions including locomotion, phagocytosis, and secretion of cytokines that requires the participation of tyrosine kinases. Fgr, Hck, and Lyn are myeloid-specific Src family kinases. Despite their constitutively high expression in macrophages, their absence does not impair LPS responsiveness. In contrast, Src, a barely detectable tyrosine kinase in resting macrophages, becomes greatly inducible in response to TLR engagement, implicating its role in macrophage activation. Indeed, silencing Src suppresses the activated TLR-mediated migration, phagocytosis, and interferon-beta (IFN-β) secretion in macrophages. And these physiological defects can be restored by the introduction of siRNA-resistant Src. Notably, the elevated expression and activity of Src is inducible nitric oxide synthase (iNOS)-dependent. Due to (1) iNOS being a NF-κB target, which can be induced by various TLR ligands, (2) Src can mediate NF-κB activation, therefore, there ought to exist a loop of signal amplification that regulates macrophage physiology in response to the engagement of TLRs.

  20. Novel receptor-like protein kinases induced by Erwinia carotovora and short oligogalacturonides in potato.

    PubMed

    Montesano, M; Kõiv, V; Mäe, A; Palva, E T

    2001-11-01

    summary Identification of potato genes responsive to cell wall-degrading enzymes of Erwinia carotovora resulted in the isolation of cDNA clones for four related receptor-like protein kinases. One of the putative serine-threonine protein kinases might have arisen through alternative splicing. These potato receptor-like kinases (PRK1-4) were highly equivalent (91-99%), most likely constituting a family of related receptors. All PRKs and four other plant RLKs share in their extracellular domain a conserved bi-modular pattern of cysteine repeats distinct from that in previously characterized plant RLKs, suggesting that they represent a new class of receptors. The corresponding genes were rapidly induced by E. carotovora culture filtrate (CF), both in the leaves and tubers of potato. Furthermore, the genes were transiently induced by short oligogalacturonides. The structural identity of PRKs and their induction pattern suggested that they constitute part of the early response of potato to E. carotovora infection.

  1. Mechanisms of Dexamethasone-Mediated Inhibition of Toll-Like Receptor Signaling Induced by Neisseria meningitidis and Streptococcus pneumoniae▿

    PubMed Central

    Mogensen, Trine H.; Berg, Randi S.; Paludan, Søren R.; Østergaard, Lars

    2008-01-01

    Excessive inflammation contributes to the pathogenesis of bacterial meningitis, which remains a serious disease despite treatment with antibiotics. Therefore, anti-inflammatory drugs have important therapeutic potential, and clinical trials have revealed that early treatment with dexamethasone significantly reduces mortality and morbidity from bacterial meningitis. Here we investigate the molecular mechanisms behind the inhibitory effect of dexamethasone upon the inflammatory responses evoked by Neisseria meningitidis and Streptococcus pneumoniae, two of the major causes of bacterial meningitis. The inflammatory cytokine response was dependent on Toll-like receptor signaling and was strongly inhibited by dexamethasone. Activation of the NF-κB pathway was targeted at several levels, including inhibition of IκB phosphorylation and NF-κB DNA-binding activity as well as upregulation of IκBα synthesis. Our data also revealed that the timing of steroid treatment relative to infection was important for achieving strong inhibition, particularly in response to S. pneumoniae. Altogether, we describe important targets of dexamethasone in the inflammatory responses evoked by N. meningitidis and S. pneumoniae, which may contribute to our understanding of the clinical effect and the importance of timing with respect to corticosteroid treatment during bacterial meningitis. PMID:17938219

  2. Effects of Toll-Like Receptor Stimulation on Eosinophilic Infiltration in Lungs of BALB/c Mice Immunized with UV-Inactivated Severe Acute Respiratory Syndrome-Related Coronavirus Vaccine

    PubMed Central

    Iwata-Yoshikawa, Naoko; Uda, Akihiko; Suzuki, Tadaki; Tsunetsugu-Yokota, Yasuko; Sato, Yuko; Morikawa, Shigeru; Tashiro, Masato; Sata, Tetsutaro; Hasegawa, Hideki

    2014-01-01

    ABSTRACT Severe acute respiratory syndrome-related coronavirus (SARS-CoV) is an emerging pathogen that causes severe respiratory illness. Whole UV-inactivated SARS-CoV (UV-V), bearing multiple epitopes and proteins, is a candidate vaccine against this virus. However, whole inactivated SARS vaccine that includes nucleocapsid protein is reported to induce eosinophilic infiltration in mouse lungs after challenge with live SARS-CoV. In this study, an ability of Toll-like receptor (TLR) agonists to reduce the side effects of UV-V vaccination in a 6-month-old adult BALB/c mouse model was investigated, using the mouse-passaged Frankfurt 1 isolate of SARS-CoV. Immunization of adult mice with UV-V, with or without alum, resulted in partial protection from lethal doses of SARS-CoV challenge, but extensive eosinophil infiltration in the lungs was observed. In contrast, TLR agonists added to UV-V vaccine, including lipopolysaccharide, poly(U), and poly(I·C) (UV-V+TLR), strikingly reduced excess eosinophilic infiltration in the lungs and induced lower levels of interleukin-4 and -13 and eotaxin in the lungs than UV-V-immunization alone. Additionally, microarray analysis showed that genes associated with chemotaxis, eosinophil migration, eosinophilia, and cell movement and the polarization of Th2 cells were upregulated in UV-V-immunized but not in UV-V+TLR-immunized mice. In particular, CD11b+ cells in the lungs of UV-V-immunized mice showed the upregulation of genes associated with the induction of eosinophils after challenge. These findings suggest that vaccine-induced eosinophil immunopathology in the lungs upon SARS-CoV infection could be avoided by the TLR agonist adjuvants. IMPORTANCE Inactivated whole severe acute respiratory syndrome-related coronavirus (SARS-CoV) vaccines induce neutralizing antibodies in mouse models; however, they also cause increased eosinophilic immunopathology in the lungs upon SARS-CoV challenge. In this study, the ability of adjuvant Toll-like

  3. Expansion of the receptor-like kinase/Pelle gene family and receptor-like proteins in Arabidopsis.

    PubMed

    Shiu, Shin Han; Bleecker, Anthony B

    2003-06-01

    Receptor-like kinases (RLKs) are a family of transmembrane proteins with versatile N-terminal extracellular domains and C-terminal intracellular kinases. They control a wide range of physiological responses in plants and belong to one of the largest gene families in the Arabidopsis genome with more than 600 members. Interestingly, this gene family constitutes 60% of all kinases in Arabidopsis and accounts for nearly all transmembrane kinases in Arabidopsis. Analysis of four fungal, six metazoan, and two Plasmodium sp. genomes indicates that the family was represented in all but fungal genomes, indicating an ancient origin for the family with a more recent expansion only in the plant lineages. The RLK/Pelle family can be divided into several subfamilies based on three independent criteria: the phylogeny based on kinase domain sequences, the extracellular domain identities, and intron locations and phases. A large number of receptor-like proteins (RLPs) resembling the extracellular domains of RLKs are also found in the Arabidopsis genome. However, not all RLK subfamilies have corresponding RLPs. Several RLK/Pelle subfamilies have undergone differential expansions. More than 33% of the RLK/Pelle members are found in tandem clusters, substantially higher than the genome average. In addition, 470 of the RLK/Pelle family members are located within the segmentally duplicated regions in the Arabidopsis genome and 268 of them have a close relative in the corresponding regions. Therefore, tandem duplications and segmental/whole-genome duplications represent two of the major mechanisms for the expansion of the RLK/Pelle family in Arabidopsis.

  4. Accelerated model of lupus autoimmunity and vasculopathy driven by toll-like receptor 7/9 imbalance

    PubMed Central

    Liu, Yudong; Seto, Nickie L; Carmona-Rivera, Carmelo; Kaplan, Mariana J

    2018-01-01

    Objectives Activation of endosomal toll-like receptor (TLR)7 or TLR9 has been proposed as a critical step for the initiation and development of SLE. Traditional spontaneous lupus models normally introduce multiple risk alleles, thereby adding additional confounding factors. In the induced lupus models, the role of TLR9 remains unclear. In the present study, we explored the role of an imbalance between TLR7 and TLR9 pathways in the pathogenesis of lupus and its associated vasculopathy using the imiquimod model in TLR9 KO/B6 background. Methods Wild type (WT) and Tlr9-/- mice were epicutaneously treated with imiquimod cream 5% on both ears three times per week for indicated times. At euthanasia, mice were analysed for organ involvement, endothelium-dependent vasorelaxation, serum autoantibodies, and innate and adaptive immune responses. Results Compared with the lupus-like phenotype that develops in imiquimod-treated WT mice, Tlr9-/- mice exposed to imiquimod have increased severity of autoimmunity features and inflammatory phenotype that develops at earlier stages. These abnormalities are characterised by enhanced TLR7 expression and immune activation, increased immune complex deposition, Th1 T cells and dendritic cell kidney infiltration and significant impairments in endothelial function. Modulation of TLR7 expression was observed in the Tlr9-/- mice. Conclusions These findings further underscore the protective role of TLR9 in TLR7-driven autoimmunity and also in the development of vasculopathy, further strengthening the importance of tightly manipulating TLRs in putative therapeutic strategies. This study provides a new model of accelerated lupus phenotype driven by danger-associated molecular patterns. PMID:29765617

  5. Toll-like receptor 4 enhancement of non-NMDA synaptic currents increases dentate excitability after brain injury.

    PubMed

    Li, Ying; Korgaonkar, Akshata A; Swietek, Bogumila; Wang, Jianfeng; Elgammal, Fatima S; Elkabes, Stella; Santhakumar, Vijayalakshmi

    2015-02-01

    Concussive brain injury results in neuronal degeneration, microglial activation and enhanced excitability in the hippocampal dentate gyrus, increasing the risk for epilepsy and memory dysfunction. Endogenous molecules released during injury can activate innate immune responses including toll-like receptor 4 (TLR4). Recent studies indicate that immune mediators can modulate neuronal excitability. Since non-specific agents that reduce TLR4 signaling can limit post-traumatic neuropathology, we examined whether TLR4 signaling contributes to early changes in dentate excitability after brain injury. Concussive brain injury caused a transient increase in hippocampal TLR4 expression within 4h, which peaked at 24h. Post-injury increase in TLR4 expression in the dentate gyrus was primarily neuronal and persisted for one week. Acute, in vitro treatment with TLR4 ligands caused bidirectional modulation of dentate excitability in control and brain-injured rats, with a reversal in the direction of modulation after brain injury. TLR4 antagonists decreased, and agonist increased, afferent-evoked dentate excitability one week after brain injury. NMDA receptor antagonist did not occlude the ability of LPS-RS, a TLR4 antagonist, to decrease post-traumatic dentate excitability. LPS-RS failed to modulate granule cell NMDA EPSCs but decreased perforant path-evoked non-NMDA EPSC peak amplitude and charge transfer in both granule cells and mossy cells. Our findings indicate an active role for TLR4 signaling in early post-traumatic dentate hyperexcitability. The novel TLR4 modulation of non-NMDA glutamatergic currents, identified herein, could represent a general mechanism by which immune activation influences neuronal excitability in neurological disorders that recruit sterile inflammatory responses. Copyright © 2014 Elsevier Inc. All rights reserved.

  6. Retinoic Acid Inducible Gene 1 Protein (RIG1)-like Receptor Pathway is Required for Efficient Nuclear Reprogramming

    PubMed Central

    Sayed, Nazish; Ospino, Frank; Himmati, Farhan; Lee, Jieun; Chanda, Palas; Mocarski, Edward S.; Cooke, John P.

    2017-01-01

    We have revealed a critical role for innate immune signaling in nuclear reprogramming to pluripotency, and in the nuclear reprogramming required for somatic cell transdifferentiation. Activation of innate immune signaling causes global changes in the expression and activity of epigenetic modifiers to promote epigenetic plasticity. In our previous papers, we focused on the role of toll-like receptor 3 (TLR3) in this signaling pathway. Here we define the role of another innate immunity pathway known to participate in the response to viral RNA, the retinoic acid-inducible gene 1 receptor (RIG-1)-like receptor (RLR) pathway. This pathway is represented by the sensors of viral RNA, RIG-1, LGP2 and MDA5. We first found that TLR3 deficiency only causes a partial inhibition of nuclear reprogramming to pluripotency in mouse tail-tip fibroblasts, which motivated us to determine the contribution of RLR. We found that knockdown of iPS-1, the common adaptor protein for the RLR family, substantially reduced nuclear reprogramming induced by retroviral or by mmRNA expression of Oct 4, Sox2, KLF4 and cMYC (OSKM). Importantly a double knockdown of both RLR and TLR3 pathway led to a further decrease in iPSC colonies suggesting an additive effect of both these pathways on nuclear reprogramming. Furthermore, in murine embryonic fibroblasts expressing a dox-inducible cassette of the genes encoding OSKM, an RLR agonist increased the yield of iPSCs. Similarly, the RLR agonist enhanced nuclear reprogramming by cell permeant peptides of the Yamanaka factors. Finally, in the dox-inducible system, RLR activation promotes activating histone marks in the promoter region of pluripotency genes. To conclude, innate immune signaling mediated by RLR plays a critical role in nuclear reprogramming. Manipulation of innate immune signaling may facilitate nuclear reprogramming to achieve pluripotency. PMID:28276156

  7. Synergic activation of toll-like receptor (TLR) 2/6 and 9 in response to Ureaplasma parvum & urealyticum in human amniotic epithelial cells.

    PubMed

    Triantafilou, Martha; De Glanville, Benjamin; Aboklaish, Ali F; Spiller, O Brad; Kotecha, Sailesh; Triantafilou, Kathy

    2013-01-01

    Ureaplasma species are the most frequently isolated microorganisms inside the amniotic cavity and have been associated with spontaneous abortion, chorioamnionitis, premature rupture of the membranes (PROM), preterm labour (PL) pneumonia in neonates and bronchopulmonary dysplasia in neonates. The mechanisms by which Ureaplasmas cause such diseases remain unclear, but it is believed that inappropriate induction of inflammatory responses is involved, triggered by the innate immune system. As part of its mechanism of activation, the innate immune system employs germ-lined encoded receptors, called pattern recognition receptors (PRRs) in order to "sense" pathogens. One such family of PRRs are the Toll like receptor family (TLR). In the current study we aimed to elucidate the role of TLRs in Ureaplasma-induced inflammation in human amniotic epithelial cells. Using silencing, as well as human embryonic kidney (HEK) transfected cell lines, we demonstrate that TLR2, TLR6 and TLR9 are involved in the inflammatory responses against Ureaplasma parvum and urealyticum serovars. Ureaplasma lipoproteins, such as Multiple Banded antigen (MBA), trigger responses via TLR2/TLR6, whereas the whole bacterium is required for TLR9 activation. No major differences were observed between the different serovars. Cell activation by Ureaplasma parvum and urealyticum seem to require lipid raft function and formation of heterotypic receptor complexes comprising of TLR2 and TLR6 on the cell surface and TLR9 intracellularly.

  8. Synergic Activation of Toll-Like Receptor (TLR) 2/6 and 9 in Response to Ureaplasma parvum & urealyticum in Human Amniotic Epithelial Cells

    PubMed Central

    Triantafilou, Martha; De Glanville, Benjamin; Aboklaish, Ali F.; Spiller, O. Brad; Kotecha, Sailesh; Triantafilou, Kathy

    2013-01-01

    Ureaplasma species are the most frequently isolated microorganisms inside the amniotic cavity and have been associated with spontaneous abortion, chorioamnionitis, premature rupture of the membranes (PROM), preterm labour (PL) pneumonia in neonates and bronchopulmonary dysplasia in neonates. The mechanisms by which Ureaplasmas cause such diseases remain unclear, but it is believed that inappropriate induction of inflammatory responses is involved, triggered by the innate immune system. As part of its mechanism of activation, the innate immune system employs germ-lined encoded receptors, called pattern recognition receptors (PRRs) in order to “sense” pathogens. One such family of PRRs are the Toll like receptor family (TLR). In the current study we aimed to elucidate the role of TLRs in Ureaplasma-induced inflammation in human amniotic epithelial cells. Using silencing, as well as human embryonic kidney (HEK) transfected cell lines, we demonstrate that TLR2, TLR6 and TLR9 are involved in the inflammatory responses against Ureaplasma parvum and urealyticum serovars. Ureaplasma lipoproteins, such as Multiple Banded antigen (MBA), trigger responses via TLR2/TLR6, whereas the whole bacterium is required for TLR9 activation. No major differences were observed between the different serovars. Cell activation by Ureaplasma parvum and urealyticum seem to require lipid raft function and formation of heterotypic receptor complexes comprising of TLR2 and TLR6 on the cell surface and TLR9 intracellularly. PMID:23593431

  9. Toll-Like Receptor 4 Is an Essential Upstream Regulator of On-Time Parturition and Perinatal Viability in Mice.

    PubMed

    Wahid, Hanan H; Dorian, Camilla L; Chin, Peck Yin; Hutchinson, Mark R; Rice, Kenner C; Olson, David M; Moldenhauer, Lachlan M; Robertson, Sarah A

    2015-10-01

    An inflammatory response is instrumental in the physiological process of parturition but the upstream signals initiating inflammation are undefined. Because endogenous ligands for Toll-like receptor 4 (TLR4) are released in late gestation, we hypothesized that on-time labor requires TLR4 signaling, to trigger a cytokine and leukocyte response and accelerate the parturition cascade. In pregnant TLR4-deficient (Tlr4-/-) mice, average gestation length was extended by 13 hours and increased perinatal mortality was seen compared with wild-type controls. Quantification of cytokine and uterine activation gene expression showed that late gestation induction of Il1b, Il6, Il12b, and Tnf expression seen in control placenta and fetal membranes was disrupted in Tlr4-/- mice, and accompanied by a transient delay in expression of uterine activation genes, including prostaglandin F receptor, oxytocin receptor, and connexin-43. Leukocyte populations were altered before birth in TLR4-deficient females, with fewer neutrophils and macrophages in the placenta, and fewer dendritic cells and more regulatory T cells in the myometrium. Administration of TLR4 ligand lipopolysaccharide to pregnant wild-type mice induced cytokine expression and fetal loss, whereas Tlr4-/- pregnancies were protected. The small molecule TLR4 antagonist (+)-naloxone increased mean duration of gestation by 16 hours in wild-type mice. Collectively, these data demonstrate that TLR4 is a key upstream regulator of the inflammatory response acting to drive uterine activation and control the timing of labor. Because causal pathways for term and preterm labor converge with TLR4, interventions to manipulate TLR4 signaling may have therapeutic utility for women at risk of preterm labor, or in postterm pregnancy.

  10. Diabetes increases the susceptibility to acute kidney injury after myocardial infarction through augmented activation of renal Toll-like receptors in rats.

    PubMed

    Ohno, Kouhei; Kuno, Atsushi; Murase, Hiromichi; Muratsubaki, Shingo; Miki, Takayuki; Tanno, Masaya; Yano, Toshiyuki; Ishikawa, Satoko; Yamashita, Tomohisa; Miura, Tetsuji

    2017-12-01

    Acute kidney injury (AKI) after acute myocardial infarction (MI) worsens the prognosis of MI patients. Although type 2 diabetes mellitus (DM) is a major risk factor of AKI after MI, the underlying mechanism remains unclear. Here, we examined the roles of renal Toll-like receptors (TLRs) in the impact of DM on AKI after MI. MI was induced by coronary artery ligation in Otsuka-Long-Evans-Tokushima fatty (OLETF) rats, a rat DM model, and Long-Evans-Tokushima-Otsuka (LETO) rats, nondiabetic controls. Sham-operated rats served as no-MI controls. Renal mRNA levels of TLR2 and myeloid differentiation factor 88 (MyD88) were significantly higher in sham-operated OLETF rats than in sham-operated LETO rats, although levels of TLR1, TLR3, and TLR4 were similar. At 12 h after MI, protein levels of kidney injury molecule-1 (KIM-1) and neutrophil gelatinase-associated lipocalin (NGAL) in the kidney were elevated by 5.3- and 4.0-fold, respectively, and their mRNA levels were increased in OLETF but not LETO rats. The increased KIM-1 and NGAL expression levels after MI in the OLETF kidney were associated with upregulated expression of TLR1, TLR2, TLR4, MyD88, IL-6, TNF-α, chemokine (C-C motif) ligand 2, and transforming growth factor-β 1 and also with activation of p38 MAPK, JNK, and NF-κB. Cu-CPT22, a TLR1/TLR2 antagonist, administered before MI significantly suppressed MI-induced upregulation of KIM-1, TLR2, TLR4, MyD88, and chemokine (C-C motif) ligand 2 levels and activation of NF-κB, whereas NGAL levels and IL-6 and TNF-α expression levels were unchanged. The results suggest that DM increases the susceptibility to AKI after acute MI by augmented activation of renal TLRs and that TLR1/TLR2-mediated signaling mediates KIM-1 upregulation after MI. NEW & NOTEWORTHY This is the first report to demonstrate the involvement of Toll-like recpetors (TLRs) in diabetes-induced susceptibility to acute kidney injury after acute myocardial infarction. We propose that the TLR1/TLR2

  11. Role of the Toll Like receptor (TLR) radical cycle in chronic inflammation: possible treatments targeting the TLR4 pathway.

    PubMed

    Lucas, Kurt; Maes, Michael

    2013-08-01

    Activation of the Toll-like receptor 4 (TLR4) complex, a receptor of the innate immune system, may underpin the pathophysiology of many human diseases, including asthma, cardiovascular disorder, diabetes, obesity, metabolic syndrome, autoimmune disorders, neuroinflammatory disorders, schizophrenia, bipolar disorder, autism, clinical depression, chronic fatigue syndrome, alcohol abuse, and toluene inhalation. TLRs are pattern recognition receptors that recognize damage-associated molecular patterns and pathogen-associated molecular patterns, including lipopolysaccharide (LPS) from gram-negative bacteria. Here we focus on the environmental factors, which are known to trigger TLR4, e.g., ozone, atmosphere particulate matter, long-lived reactive oxygen intermediate, pentachlorophenol, ionizing radiation, and toluene. Activation of the TLR4 pathways may cause chronic inflammation and increased production of reactive oxygen and nitrogen species (ROS/RNS) and oxidative and nitrosative stress and therefore TLR-related diseases. This implies that drugs or substances that modify these pathways may prevent or improve the abovementioned diseases. Here we review some of the most promising drugs and agents that have the potential to attenuate TLR-mediated inflammation, e.g., anti-LPS strategies that aim to neutralize LPS (synthetic anti-LPS peptides and recombinant factor C) and TLR4/MyD88 antagonists, including eritoran, CyP, EM-163, epigallocatechin-3-gallate, 6-shogaol, cinnamon extract, N-acetylcysteine, melatonin, and molecular hydrogen. The authors posit that activation of the TLR radical (ROS/RNS) cycle is a common pathway underpinning many "civilization" disorders and that targeting the TLR radical cycle may be an effective method to treat many inflammatory disorders.

  12. Respiratory Influenza A Virus Infection Triggers Local and Systemic Natural Killer Cell Activation via Toll-Like Receptor 7.

    PubMed

    Stegemann-Koniszewski, Sabine; Behrens, Sarah; Boehme, Julia D; Hochnadel, Inga; Riese, Peggy; Guzmán, Carlos A; Kröger, Andrea; Schreiber, Jens; Gunzer, Matthias; Bruder, Dunja

    2018-01-01

    The innate immune system senses influenza A virus (IAV) through different pathogen-recognition receptors including Toll-like receptor 7 (TLR7). Downstream of viral recognition natural killer (NK) cells are activated as part of the anti-IAV immune response. Despite the known decisive role of TLR7 for NK cell activation by therapeutic immunostimulatory RNAs, the contribution of TLR7 to the NK cell response following IAV infection has not been addressed. We have analyzed lung cytokine responses as well as the activation, interferon (IFN)-γ production, and cytotoxicity of lung and splenic NK cells following sublethal respiratory IAV infection in wild-type and TLR7ko mice. Early airway IFN-γ levels as well as the induction of lung NK cell CD69 expression and IFN-γ production in response to IAV infection were significantly attenuated in TLR7-deficient hosts. Strikingly, respiratory IAV infection also primed splenic NK cells for IFN-γ production, degranulation, and target cell lysis, all of which were fully dependent on TLR7. At the same time, lung type I IFN levels were significantly reduced in TLR7ko mice early following IAV infection, displaying a potential upstream mechanism of the attenuated NK cell activation observed. Taken together, our data clearly demonstrate a specific role for TLR7 signaling in local and systemic NK cell activation following respiratory IAV infection despite the presence of redundant innate IAV-recognition pathways.

  13. Respiratory Influenza A Virus Infection Triggers Local and Systemic Natural Killer Cell Activation via Toll-Like Receptor 7

    PubMed Central

    Stegemann-Koniszewski, Sabine; Behrens, Sarah; Boehme, Julia D.; Hochnadel, Inga; Riese, Peggy; Guzmán, Carlos A.; Kröger, Andrea; Schreiber, Jens; Gunzer, Matthias; Bruder, Dunja

    2018-01-01

    The innate immune system senses influenza A virus (IAV) through different pathogen-recognition receptors including Toll-like receptor 7 (TLR7). Downstream of viral recognition natural killer (NK) cells are activated as part of the anti-IAV immune response. Despite the known decisive role of TLR7 for NK cell activation by therapeutic immunostimulatory RNAs, the contribution of TLR7 to the NK cell response following IAV infection has not been addressed. We have analyzed lung cytokine responses as well as the activation, interferon (IFN)-γ production, and cytotoxicity of lung and splenic NK cells following sublethal respiratory IAV infection in wild-type and TLR7ko mice. Early airway IFN-γ levels as well as the induction of lung NK cell CD69 expression and IFN-γ production in response to IAV infection were significantly attenuated in TLR7-deficient hosts. Strikingly, respiratory IAV infection also primed splenic NK cells for IFN-γ production, degranulation, and target cell lysis, all of which were fully dependent on TLR7. At the same time, lung type I IFN levels were significantly reduced in TLR7ko mice early following IAV infection, displaying a potential upstream mechanism of the attenuated NK cell activation observed. Taken together, our data clearly demonstrate a specific role for TLR7 signaling in local and systemic NK cell activation following respiratory IAV infection despite the presence of redundant innate IAV-recognition pathways. PMID:29497422

  14. Unc93B1 biases Toll-like receptor responses to nucleic acid in dendritic cells toward DNA- but against RNA-sensing.

    PubMed

    Fukui, Ryutaro; Saitoh, Shin-ichiroh; Matsumoto, Fumi; Kozuka-Hata, Hiroko; Oyama, Masaaki; Tabeta, Koichi; Beutler, Bruce; Miyake, Kensuke

    2009-06-08

    Toll-like receptors (TLRs) 3, 7, and 9 recognize microbial nucleic acids in endolysosomes and initiate innate and adaptive immune responses. TLR7/9 in dendritic cells (DCs) also respond to self-derived RNA/DNA, respectively, and drive autoantibody production. Remarkably, TLR7 and 9 appear to have mutually opposing, pathogenic or protective, impacts on lupus nephritis in MRL/lpr mice. Little is known, however, about the contrasting relationship between TLR7 and 9. We show that TLR7 and 9 are inversely linked by Unc93B1, a multiple membrane-spanning endoplasmic reticulum (ER) protein. Complementation cloning with a TLR7-unresponsive but TLR9-responsive cell line revealed that amino acid D34 in Unc93B1 repressed TLR7-mediated responses. D34A mutation rendered Unc93B1-deficient DCs hyperresponsive to TLR7 ligand but hyporesponsive to TLR9 ligand, with TLR3 responses unaltered. Unc93B1 associates with and delivers TLR7/9 from the ER to endolysosomes for ligand recognition. The D34A mutation up-regulates Unc93B1 association with endogenous TLR7 in DCs, whereas Unc93B1 association with TLR9 was down-regulated by the D34A mutation. Consistently, the D34A mutation up-regulated ligand-induced trafficking of TLR7 but down-regulated that of TLR9. Collectively, TLR response to nucleic acids in DCs is biased toward DNA-sensing by Unc93B1.

  15. Absorption of PCB126 by upper airways impairs G protein-coupled receptor-mediated immune response

    NASA Astrophysics Data System (ADS)

    Shimada, Ana Lúcia B.; Cruz, Wesley S.; Loiola, Rodrigo A.; Drewes, Carine C.; Dörr, Fabiane; Figueiredo, Natália G.; Pinto, Ernani; Farsky, Sandra H. P.

    2015-10-01

    PCB126 is a dioxin-like polychlorinated biphenyl (PCB) environmental pollutant with a significant impact on human health, as it bioaccumulates and causes severe toxicity. PCB126-induced immune toxicity has been described, although the mechanisms have not been fully elucidated. In this study, an in vivo protocol of PCB126 intoxication into male Wistar rats by intranasal route was used, which has not yet been described. The intoxication was characterised by PCB126 accumulation in the lungs and liver, and enhanced aryl hydrocarbon receptor expression in the liver, lungs, kidneys, and adipose tissues. Moreover, an innate immune deficiency was characterised by impairment of adhesion receptors on blood leukocytes and by reduced blood neutrophil locomotion and oxidative burst activation elicited by ex vivo G protein-coupled receptor (GPCR) activation. Specificity of PCB126 actions on the GPCR pathway was shown by normal burst oxidative activation evoked by Toll-like receptor 4 and protein kinase C direct activation. Moreover, in vivo PCB180 intoxication did not alter adhesion receptors on blood leukocytes either blood neutrophil locomotion, and only partially reduced the GPCR-induced burst oxidative activation on neutrophils. Therefore, a novel mechanism of in vivo PCB126 toxicity is described which impairs a pivotal inflammatory pathway to the host defence against infections.

  16. Immune signaling by RIG-I-like receptors

    PubMed Central

    Loo, Yueh-Ming; Gale, Michael

    2011-01-01

    The RIG-I-like receptors (RLRs) RIG-I, MDA5, and LGP2 play a major role in pathogen sensing of RNA virus infection to initiate and modulate antiviral immunity. The RLRs detect viral RNA ligands or processed self RNA in the cytoplasm to triggers innate immunity and inflammation and to impart gene expression that serves to control infection. Importantly, RLRs cooperate in signaling crosstalk networks with Toll-like receptors and other factors to impart innate immunity and to modulate the adaptive immune response. RLR regulation occurs at a variety of levels ranging from autoregulation to ligand and co-factor interactions and post-translational modifications. Abberant RLR signaling or dysregulation of RLR expression is now implicated in the development of autoimmune diseases. Understanding the processes of RLR signaling and response will provide insights to guide RLR-targeted therapeutics for antiviral and immune modifying applications. PMID:21616437

  17. The common food additive carrageenan is not a ligand for Toll-Like- Receptor 4 (TLR4) in an HEK293-TLR4 reporter cell-line model.

    PubMed

    McKim, James M; Wilga, Paul C; Pregenzer, Jeffrey F; Blakemore, William R

    2015-04-01

    Carrageenan (CGN) is widely used in the food manufacturing industry as an additive that stabilizes and thickens food products. Standard animal safety studies in which CGN was administered in diet showed no adverse effects. However, several in vitro studies have reported that intestinal inflammation is caused by CGN and that this effect is mediated through Toll-Like-Receptor 4 (TLR4). The purpose of this study was to evaluate the ability of different types of CGN to bind and activate TLR4 signaling. To accomplish this a TLR4/MD-2/CD14/NFκB/SEAP reporter construct in a HEK293 cell line was used. The reporter molecule, secretable alkaline phosphatase (SEAP), was measured as an indicator of TLR4 activation. The test compounds were exposed to this system at concentrations of 0.1, 1, 10, 50, 100, 500, 1000, and 5000 ng/mL for 24 h. Cytotoxicity was evaluated following the 24 h exposure period by LDH leakage and ATP. CGN binding to serum proteins was characterized by Toluidine Blue. The results show that CGN does not bind to TLR4 and is not cytotoxic to the HEK293 cells at the concentrations and experimental conditions tested and that CGN binds tightly to serum proteins. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

  18. Inhibition of toll-like receptor 3-4 with ethanolic extract of propolis on innate immunity in diabetes mellitus mice (Mus musculus)

    NASA Astrophysics Data System (ADS)

    Pristiwanto, Bambang; Soewondo, A.; Sumitro, Sutiman B.; Rifa'i, Muhaimin

    2017-05-01

    One of the most significant problems today is to treat the effects of metabolic diseases, such as diabetes. Thus, this study evaluated the ability of an ethanolic extract of propolis (EEP) to reduce inflammation in diabetes treatment. The used mice with STZ-induced diabetes mellitus (SID) and the expression of Toll-Like Receptor 3-4 was analyzed in their innate immunity cells. The SID mice had a higher TLR 3-4 expression compared with the healthy control group. Treatment of EEP in SID using three different doses significantly decreased the number of B cells with TLR 3-4 expression. This suggesting that EEP treatment decreases TLR3 & TLR4 expression on innate immunity (especially B cells) from over expression in SID which can affect the acute inflammatory and aggravate the diabetes condition. Even relatively low doses of propolis extract can decrease TLR3 and TLR4 expressed by B cell.

  19. Purification of family B G protein-coupled receptors using nanodiscs: Application to human glucagon-like peptide-1 receptor.

    PubMed

    Cai, Yingying; Liu, Yuting; Culhane, Kelly J; DeVree, Brian T; Yang, Yang; Sunahara, Roger K; Yan, Elsa C Y

    2017-01-01

    Family B G protein-coupled receptors (GPCRs) play vital roles in hormone-regulated homeostasis. They are drug targets for metabolic diseases, including type 2 diabetes and osteoporosis. Despite their importance, the signaling mechanisms for family B GPCRs at the molecular level remain largely unexplored due to the challenges in purification of functional receptors in sufficient amount for biophysical characterization. Here, we purified the family B GPCR human glucagon-like peptide-1 (GLP-1) receptor (GLP1R), whose agonists, e.g. exendin-4, are used for the treatment of type 2 diabetes mellitus. The receptor was expressed in HEK293S GnTl- cells using our recently developed protocol. The protocol incorporates the receptor into the native-like lipid environment of reconstituted high density lipoprotein (rHDL) particles, also known as nanodiscs, immediately after the membrane solubilization step followed by chromatographic purification, minimizing detergent contact with the target receptor to reduce denaturation and prolonging stabilization of receptor in lipid bilayers without extra steps of reconstitution. This method yielded purified GLP1R in nanodiscs that could bind to GLP-1 and exendin-4 and activate Gs protein. This nanodisc purification method can potentially be a general strategy to routinely obtain purified family B GPCRs in the 10s of microgram amounts useful for spectroscopic analysis of receptor functions and activation mechanisms.

  20. Purification of family B G protein-coupled receptors using nanodiscs: Application to human glucagon-like peptide-1 receptor

    PubMed Central

    Cai, Yingying; Liu, Yuting; Culhane, Kelly J.; DeVree, Brian T.; Yang, Yang; Sunahara, Roger K.; Yan, Elsa C. Y.

    2017-01-01

    Family B G protein-coupled receptors (GPCRs) play vital roles in hormone-regulated homeostasis. They are drug targets for metabolic diseases, including type 2 diabetes and osteoporosis. Despite their importance, the signaling mechanisms for family B GPCRs at the molecular level remain largely unexplored due to the challenges in purification of functional receptors in sufficient amount for biophysical characterization. Here, we purified the family B GPCR human glucagon-like peptide-1 (GLP-1) receptor (GLP1R), whose agonists, e.g. exendin-4, are used for the treatment of type 2 diabetes mellitus. The receptor was expressed in HEK293S GnTl- cells using our recently developed protocol. The protocol incorporates the receptor into the native-like lipid environment of reconstituted high density lipoprotein (rHDL) particles, also known as nanodiscs, immediately after the membrane solubilization step followed by chromatographic purification, minimizing detergent contact with the target receptor to reduce denaturation and prolonging stabilization of receptor in lipid bilayers without extra steps of reconstitution. This method yielded purified GLP1R in nanodiscs that could bind to GLP-1 and exendin-4 and activate Gs protein. This nanodisc purification method can potentially be a general strategy to routinely obtain purified family B GPCRs in the 10s of microgram amounts useful for spectroscopic analysis of receptor functions and activation mechanisms. PMID:28609478

  1. Role of salivary epithelial toll-like receptors 2 and 4 in modulating innate immune responses in chronic periodontitis.

    PubMed

    Swaminathan, V; Prakasam, S; Puri, V; Srinivasan, M

    2013-12-01

    Chronic periodontitis is initiated by sequential colonization with a broad array of bacteria and is perpetuated by an immune-inflammatory response to the changing biofilm. Host recognition of microbes is largely mediated by toll-like receptors (TLRs), which interact with conserved pathogen-associated molecular patterns. Based on ligand recognition, TLR-2 and TLR-4 interact with most periodontal pathogens. Extracrevicular bacterial reservoirs, such as the oral epithelial cells, contribute to the persistence of periodontitis. Human saliva is a rich source of oral epithelial cells that express functional TLRs. In this study we investigated the role of salivary epithelial cell (SEC) TLR-2 and TLR-4 in patients with generalized chronic periodontitis. Unstimulated whole saliva (UWS) was collected from patients with generalized chronic periodontitis and from healthy individuals after obtaining informed consent. Epithelial cells isolated from each UWS sample were assessed for TLR-2, TLR-4, peptidoglycan recognition protein (PGRP)-3 and PGRP-4 by quantitative real-time PCR. In addition, the SECs were stimulated in vitro with microbial products for up to 24 h. The culture supernatant was assessed for cytokines by ELISA. Stimulation with TLR-2- or TLR-4-specific ligands induced cytokine secretion with differential kinetics and up-regulated TLR2 and TLR4 mRNAs, respectively, in cultures of SECs from patients with periodontitis. In addition, the SECs from patients with periodontitis exhibited reduced PGRP3 and PGRP4 mRNAs, the TLR-responsive genes with antibacterial properties. SECs derived from the UWS of patients with chronic periodontitis are phenotypically distinct and could represent potential resources for assessing the epithelial responses to periodontal pathogens in the course of disease progression and persistence. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  2. Pharmacological Inhibition of Macrophage Toll-like Receptor 4/Nuclear Factor-kappa B Alleviates Rhabdomyolysis-induced Acute Kidney Injury.

    PubMed

    Huang, Rong-Shuang; Zhou, Jiao-Jiao; Feng, Yu-Ying; Shi, Min; Guo, Fan; Gou, Shen-Ju; Salerno, Stephen; Ma, Liang; Fu, Ping

    2017-09-20

    Acute kidney injury (AKI) is the most common and life-threatening systemic complication of rhabdomyolysis. Inflammation plays an important role in the development of rhabdomyolysis-induced AKI. This study aimed to investigate the kidney model of AKI caused by rhabdomyolysis to verify the role of macrophage Toll-like receptor 4/nuclear factor-kappa B (TLR4/NF-κB) signaling pathway. C57BL/6 mice were injected with a 50% glycerin solution at bilateral back limbs to induce rhabdomyolysis, and CLI-095 or pyrrolidine dithiocarbamate (PDTC) was intraperitoneally injected at 0.5 h before molding. Serum creatinine levels, creatine kinase, the expression of tumor necrosis factor (TNF)-α, interleukin (IL)-1β and IL-6, and hematoxylin and eosin stainings of kidney tissues were tested. The infiltration of macrophage, mRNA levels, and protein expression of TLR4 and NF-κB were investigated by immunofluorescence double-staining techniques, reverse transcriptase-quantitative polymerase chain reaction, and Western blotting, respectively. In vitro, macrophage RAW264.7 was stimulated by ferrous myoglobin; the cytokines, TLR4 and NF-κB expressions were also detected. In an in vivo study, using CLI-095 or PDTC to block TLR4/NF-κB, functional and histologic results showed that the inhibition of TLR4 or NF-κB alleviated glycerol-induced renal damages (P < 0.01). CLI-095 or PDTC administration suppressed proinflammatory cytokine (TNF-α, IL-6, and IL-1β) production and macrophage infiltration into the kidney (P < 0.01). Moreover, in an in vitro study, CLI-095 or PDTC suppressed myoglobin-induced expression of TLR4, NF-κB, and proinflammatory cytokine levels in macrophage RAW264.7 cells (P < 0.01). The pharmacological inhibition of TLR4/NF-κB exhibited protective effects on rhabdomyolysis-induced AKI by the regulation of proinflammatory cytokine production and macrophage infiltration.

  3. Differential cell reaction upon Toll-like receptor 4 and 9 activation in human alveolar and lung interstitial macrophages

    PubMed Central

    2010-01-01

    Background Investigations on pulmonary macrophages (MΦ) mostly focus on alveolar MΦ (AM) as a well-defined cell population. Characteristics of MΦ in the interstitium, referred to as lung interstitial MΦ (IM), are rather ill-defined. In this study we therefore aimed to elucidate differences between AM and IM obtained from human lung tissue. Methods Human AM and IM were isolated from human non-tumor lung tissue from patients undergoing lung resection. Cell morphology was visualized using either light, electron or confocal microscopy. Phagocytic activity was analyzed by flow cytometry as well as confocal microscopy. Surface marker expression was measured by flow cytometry. Toll-like receptor (TLR) expression patterns as well as cytokine expression upon TLR4 or TLR9 stimulation were assessed by real time RT-PCR and cytokine protein production was measured using a fluorescent bead-based immunoassay. Results IM were found to be smaller and morphologically more heterogeneous than AM, whereas phagocytic activity was similar in both cell types. HLA-DR expression was markedly higher in IM compared to AM. Although analysis of TLR expression profiles revealed no differences between the two cell populations, AM and IM clearly varied in cell reaction upon activation. Both MΦ populations were markedly activated by LPS as well as DNA isolated from attenuated mycobacterial strains (M. bovis H37Ra and BCG). Whereas AM expressed higher amounts of inflammatory cytokines upon activation, IM were more efficient in producing immunoregulatory cytokines, such as IL10, IL1ra, and IL6. Conclusion AM appear to be more effective as a non-specific first line of defence against inhaled pathogens, whereas IM show a more pronounced regulatory function. These dissimilarities should be taken into consideration in future studies on the role of human lung MΦ in the inflammatory response. PMID:20843333

  4. Distribution of bovine alpha-herpesviruses and expression of toll-like receptors in the respiratory system of experimentally infected calves.

    PubMed

    Marin, M S; Quintana, S; Leunda, M R; Odeón, A C; Pérez, S E

    2016-04-01

    This study provides an initial analysis of the toll-like receptors (TLRs) that might be implicated in alpha-herpesvirus infection of the bovine respiratory system. A significant variation in the expression of TLR3 and TLRs 7-9 during bovine herpesvirus type 1 (BoHV-1) and 5 (BoHV-5) acute infections and particularly an up-regulation during viral reactivation in respiratory tissues has been demonstrated. Furthermore, viral distribution in the respiratory tract of BoHV-1- and BoHV-5-infected calves at different stages of the infectious cycle was analysed. The wide distribution of BoHV DNA in the respiratory tract during acute infection was restricted during latent infection and the subsequent reactivation of BoHV-1 and BoHV-5. Overall, the findings presented here contribute to the knowledge on the replication and dissemination of bovine alpha-herpesviruses. Furthermore, some of the immune factors triggered in the host that determine the different outcomes of infection by two closely related pathogens of cattle have been elucidated. Copyright © 2016 Elsevier Ltd. All rights reserved.

  5. Single-cell systems level analysis of human Toll-Like-Receptor activation defines a chemokine signature in Systemic Lupus Erythematosus

    PubMed Central

    O'Gorman, William E.; Hsieh, Elena W.Y.; Savig, Erica S.; Gherardini, Pier Federico; Hernandez, Joseph D.; Hansmann, Leo; Balboni, Imelda M.; Utz, Paul J.; Bendall, Sean C.; Fantl, Wendy J.; Lewis, David B.; Nolan, Garry P.; Davis, Mark M.

    2015-01-01

    Background Activation of Toll-Like Receptors (TLRs) induces inflammatory responses involved in immunity to pathogens and autoimmune pathogenesis, such as in Systemic Lupus Erythematosus (SLE). Although TLRs are differentially expressed across the immune system, a comprehensive analysis of how multiple immune cell subsets respond in a system-wide manner has previously not been described. Objective To characterize TLR activation across multiple immune cell subsets and individuals, with the goal of establishing a reference framework against which to compare pathological processes. Methods Peripheral whole blood samples were stimulated with TLR ligands, and analyzed by mass cytometry simultaneously for surface marker expression, activation states of intracellular signaling proteins, and cytokine production. We developed a novel data visualization tool to provide an integrated view of TLR signaling networks with single-cell resolution. We studied seventeen healthy volunteer donors and eight newly diagnosed untreated SLE patients. Results Our data revealed the diversity of TLR-induced responses within cell types, with TLR ligand specificity. Subsets of NK and T cells selectively induced NF-κB in response to TLR2 ligands. CD14hi monocytes exhibited the most polyfunctional cytokine expression patterns, with over 80 distinct cytokine combinations. Monocytic TLR-induced cytokine patterns were shared amongst a group of healthy donors, with minimal intra- and inter- individual variability. Furthermore, autoimmune disease altered baseline cytokine production, as newly diagnosed untreated SLE patients shared a distinct monocytic chemokine signature, despite clinical heterogeneity. Conclusion Mass cytometry analysis defined a systems-level reference framework for human TLR activation, which can be applied to study perturbations in inflammatory disease, such as SLE. PMID:26037552

  6. Vibrational resonance, allostery, and activation in rhodopsin-like G protein-coupled receptors

    PubMed Central

    Woods, Kristina N.; Pfeffer, Jürgen; Dutta, Arpana; Klein-Seetharaman, Judith

    2016-01-01

    G protein-coupled receptors are a large family of membrane proteins activated by a variety of structurally diverse ligands making them highly adaptable signaling molecules. Despite recent advances in the structural biology of this protein family, the mechanism by which ligands induce allosteric changes in protein structure and dynamics for its signaling function remains a mystery. Here, we propose the use of terahertz spectroscopy combined with molecular dynamics simulation and protein evolutionary network modeling to address the mechanism of activation by directly probing the concerted fluctuations of retinal ligand and transmembrane helices in rhodopsin. This approach allows us to examine the role of conformational heterogeneity in the selection and stabilization of specific signaling pathways in the photo-activation of the receptor. We demonstrate that ligand-induced shifts in the conformational equilibrium prompt vibrational resonances in the protein structure that link the dynamics of conserved interactions with fluctuations of the active-state ligand. The connection of vibrational modes creates an allosteric association of coupled fluctuations that forms a coherent signaling pathway from the receptor ligand-binding pocket to the G-protein activation region. Our evolutionary analysis of rhodopsin-like GPCRs suggest that specific allosteric sites play a pivotal role in activating structural fluctuations that allosterically modulate functional signals. PMID:27849063

  7. Use of Toll-Like Receptor Agonists to Induce Ectopic Lymphoid Structures in Myasthenia Gravis Mouse Models

    PubMed Central

    Robinet, Marieke; Villeret, Bérengère; Maillard, Solène; Cron, Mélanie A.; Berrih-Aknin, Sonia; Le Panse, Rozen

    2017-01-01

    Myasthenia gravis (MG) is an autoimmune disease mediated by autoantibodies against the acetylcholine receptor (AChR) at the neuromuscular junction. MG symptoms are characterized by muscle weaknesses. The thymus of MG patients is very often abnormal and possesses all the characteristics of tertiary lymphoid organs such as neoangiogenesis processes, overexpression of inflammatory cytokines and chemokines, and infiltration of B lymphocytes leading to ectopic germinal center (GC) development. We previously demonstrated that injections of mice with polyinosinic–polycytidylic acid [Poly(I:C)], a synthetic double-stranded RNA mimicking viral infection, induce thymic changes and trigger MG symptoms. Upon Poly(I:C) injections, we observed increased thymic expressions of α-AChR, interferon-β and chemokines such as CXCL13 and CCL21 leading to B-cell recruitment. However, these changes were only transient. In order to develop an experimental MG model associated with thymic GCs, we used Poly(I:C) in the classical experimental autoimmune MG model induced by immunizations with purified AChR emulsified in complete Freund’s adjuvant. We observed that Poly(I:C) strongly favored the development of MG as almost all mice displayed MG symptoms. Nevertheless, we did not observe any ectopic GC development. We next challenged mice with Poly(I:C) together with other toll-like receptor (TLR) agonists known to be involved in GC development and that are overexpressed in MG thymuses. Imiquimod and CpG oligodeoxynucleotides that activate TLR7 and TLR9, respectively, did not induce thymic changes. In contrast, lipopolysaccharide that activates TLR4 potentiated Poly(I:C) effects and induced a significant expression of CXCL13 mRNA in the thymus associated with a higher recruitment of B cells that induced over time thymic B-lymphoid structures. Altogether, these data suggest that tertiary lymphoid genesis in MG thymus could result from a combined activation of TLR signaling pathways. PMID

  8. Toll-like receptor 4 protects against stress-induced ulcers via regulation of glucocorticoid production in mice.

    PubMed

    Wang, Liang; Luo, Pengfei; Zhang, Fang; Zhang, Yuelu; Wang, Xingtong; Chang, Fei; Zhang, Yuechan; Tang, Hongtai; Xia, Zhaofan

    2017-01-01

    Stress-induced gastric ulcer is an important life-threatening condition, while the molecular basis of its development is incompletely understood. Toll-like receptor 4 (TLR4), an innate immune pattern recognition receptor, can induce pro-inflammatory transcription, aggravating a stress ulcer. The present study found that TLR4 played a protective role in a mouse model of water immersion (23 °C) restraint stress. Wild-type (WT) and TLR4 -/- male mice were respectively divided into five groups (5 per group), and exposed to the stressor for 0, 0.5, 1, 2, or 4 hours. Gastric ulcer index, determined post mortem, increased with time in both types of mice but was greater in TLR4 -/- mice. Furthermore, increased serum cortisol and corticosterone concentrations were observed in WT mice only, and such increases were detected only in WT mice 4 h after lipopolysaccharide (LPS) treatment (2 mg/kg, intraperitoneal injection). Moreover, the administration of cortisol alleviated the gastric injury in TLR4 -/- mice. Western blotting showed expression in the adrenal of P450scc (CYP11A1), the first rate-limiting enzyme in the synthesis of steroids, was increased 4 h after water immersion restraint stress or LPS treatment in WT mice, but was conversely decreased in TLR4 -/- mice after either stressor. Furthermore, in adrenal glands of TLR4 -/- mice, structural distortion of mitochondria (which contain CYP11A1) was found with electron microscopy, and lack of lipid-storing droplets was found using light microscopy on adrenal cryosections stained with Oil red O. These data indicate that TLR4 plays a protective role in stress-induced gastric ulcer that is exerted via impacting synthesis of glucocorticoid in the adrenal gland.

  9. Toll-like receptors-2 and 4 are overexpressed in an experimental model of particle-induced osteolysis.

    PubMed

    Valladares, Roberto D; Nich, Christophe; Zwingenberger, Stefan; Li, Chenguang; Swank, Katherine R; Gibon, Emmanuel; Rao, Allison J; Yao, Zhenyu; Goodman, Stuart B

    2014-09-01

    Aseptic loosening secondary to particle-associated periprosthetic osteolysis remains a major cause of failure of total joint replacements (TJR) in the mid- and long term. As sentinels of the innate immune system, macrophages are central to the recognition and initiation of the inflammatory cascade, which results in the activation of bone resorbing osteoclasts. Toll-like receptors (TLRs) are involved in the recognition of pathogen-associated molecular patterns and danger-associated molecular patterns. Experimentally, polymethylmethacrylate and polyethylene (PE) particles have been shown to activate macrophages via the TLR pathway. The specific TLRs involved in PE particle-induced osteolysis remain largely unknown. We hypothesized that TLR-2, -4, and -9 mediated responses play a critical role in the development of PE wear particle-induced osteolysis in the murine calvarium model. To test this hypothesis, we first demonstrated that PE particles caused observable osteolysis, visible by microCT and bone histomorphometry when the particles were applied to the calvarium of C57BL/6 mice. The number of TRAP positive osteoclasts was significantly greater in the PE-treated group when compared to the control group without particles. Finally, using immunohistochemistry, TLR-2 and TLR-4 were highly expressed in PE particle-induced osteolytic lesions, whereas TLR-9 was downregulated. TLR-2 and -4 may represent novel therapeutic targets for prevention of wear particle-induced osteolysis and accompanying TJR failure. © 2013 Wiley Periodicals, Inc.

  10. PI3K/Akt contributes to increased expression of Toll-like receptor 4 in macrophages exposed to hypoxic stress

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Kim, So Young; Jeong, Eunshil; Joung, Sun Myung

    2012-03-16

    Highlights: Black-Right-Pointing-Pointer Hypoxic stress-induced TLR4 expression is mediated by PI3K/Akt in macrophages. Black-Right-Pointing-Pointer PI3K/Akt regulated HIF-1 activation leading to TLR4 expression. Black-Right-Pointing-Pointer p38 mitogen-activated protein kinase was not involved in TLR4 expression by hypoxic stress. Black-Right-Pointing-Pointer Sulforaphane suppressed hypoxia-mediated TLR4 expression by inhibiting PI3K/Akt. -- Abstract: Toll-like receptors (TLRs) play critical roles in triggering immune and inflammatory responses by detecting invading microbial pathogens and endogenous danger signals. Increased expression of TLR4 is implicated in aggravated inflammatory symptoms in ischemic tissue injury and chronic diseases. Results from our previous study showed that TLR4 expression was upregulated by hypoxic stress mediated bymore » hypoxia-inducible factor-1 (HIF-1) at a transcriptional level in macrophages. In this study, we further investigated the upstream signaling pathway that contributed to the increase of TLR4 expression by hypoxic stress. Either treatment with pharmacological inhibitors of PI3K and Akt or knockdown of Akt expression by siRNA blocked the increase of TLR4 mRNA and protein levels in macrophages exposed to hypoxia and CoCl{sub 2}. Phosphorylation of Akt by hypoxic stress preceded nuclear accumulation of HIF-1{alpha}. A PI3K inhibitor (LY294002) attenuated CoCl{sub 2}-induced nuclear accumulation and transcriptional activation of HIF-1{alpha}. In addition, HIF-1{alpha}-mediated upregulation of TLR4 expression was blocked by LY294002. Furthermore, sulforaphane suppressed hypoxia- and CoCl{sub 2}-induced upregulation of TLR4 mRNA and protein by inhibiting PI3K/Akt activation and the subsequent nuclear accumulation and transcriptional activation of HIF-1{alpha}. However, p38 was not involved in HIF-1{alpha} activation and TLR4 expression induced by hypoxic stress in macrophages. Collectively, our results demonstrate that PI3K

  11. Toll-like receptor 4 mediates fat, sugar, and umami taste preference and food intake and body weight regulation.

    PubMed

    Camandola, Simonetta; Mattson, Mark P

    2017-07-01

    Immune and inflammatory pathways play important roles in the pathogenesis of metabolic disorders. This study investigated the role of toll-like receptor 4 (TLR4) in orosensory detection of dietary lipids and sugars. Taste preferences of TLR4 knockout (KO) and wild-type (WT) male mice under a standard and a high-fat, high-sugar diet were assessed with two-bottle tests. Gene expression of taste signaling molecules was analyzed in the tongue epithelium. The role of TLR4 in food intake and weight gain was investigated in TLR4 KO and WT mice fed a high-fat and high-sugar diet for 12 weeks. Compared to WT mice, TLR4 KO mice showed reduced preference for lipids, sugars, and umami in a two-bottle preference test. The altered taste perception was associated with decreased levels of key taste regulatory molecules in the tongue epithelium. TLR4 KO mice on a high-fat and high-sugar diet consumed less food and drink, resulting in diminished weight gain. TLR4 signaling promotes ingestion of sugar and fat by a mechanism involving increased preference for such obesogenic foods. © 2017 The Obesity Society.

  12. T-cell activation is enhanced by targeting IL-10 cytokine production in toll-like receptor-stimulated macrophages

    PubMed Central

    Walk, Ryan M; Elliott, Steven T; Blanco, Felix C; Snyder, Jason A; Jacobi, Ashley M; Rose, Scott D; Behlke, Mark A; Salem, Aliasger K; Vukmanovic, Stanislav; Sandler, Anthony D

    2012-01-01

    Toll-like receptor (TLR) agonists represent potentially useful cancer vaccine adjuvants in their ability to stimulate antigen-presenting cells (APCs) and subsequently amplify the cytotoxic T-cell response. The purpose of this study was to characterize APC responses to TLR activation and to determine the subsequent effect on lymphocyte activation. We exposed murine primary bone marrow-derived macrophages to increasing concentrations of agonists to TLRs 2, 3, 4, and 9. This resulted in a dose-dependent increase in production of not only tumor necrosis factor–alpha (TNF-α), a surrogate marker of the proinflammatory response, but also interleukin 10 (IL-10), a well-described inhibitory cytokine. Importantly, IL-10 secretion was not induced by low concentrations of TLR agonists that readily produced TNF-α. We subsequently stimulated lymphocytes with anti-CD3 antibody in the presence of media from macrophages activated with higher doses of TLR agonists and observed suppression of interferon gamma release. Use of both IL-10 knockout macrophages and IL-10 small-interfering RNA (siRNA) ablated this suppressive effect. Finally, IL-10 siRNA was successfully used to suppress CpG-induced IL-10 production in vivo. We conclude that TLR-mediated APC stimulation can induce a paradoxical inhibitory effect on T-cell activation mediated by IL-10. PMID:27471682

  13. Toll-like receptor 4 promotes autonomic dysfunction, inflammation and microglia activation in the hypothalamic paraventricular nucleus: role of endoplasmic reticulum stress.

    PubMed

    Masson, Gustavo S; Nair, Anand R; Dange, Rahul B; Silva-Soares, Pedro Paulo; Michelini, Lisete C; Francis, Joseph

    2015-01-01

    Toll-like receptor 4 (TLR4) signaling induces tissue pro-inflammatory cytokine release and endoplasmic reticulum (ER) stress. We examined the role of TLR4 in autonomic dysfunction and the contribution of ER stress. Our study included animals divided in 6 experimental groups: rats treated with saline (i.v., 0.9%), LPS (i.v., 10mg/kg), VIPER (i.v., 0.1 mg/kg), or 4-PBA (i.p., 10 mg/kg). Two other groups were pretreated either with VIPER (TLR4 viral inhibitory peptide) LPS + VIPER (i.v., 0.1 mg/kg) or 4-Phenyl butyric acid (4-PBA) LPS + PBA (i.p., 10 mg/kg). Arterial pressure (AP) and heart rate (HR) were measured in conscious Sprague-Dawley rats. AP, HR variability, as well as baroreflex sensitivity (BrS), was determined after LPS or saline treatment for 2 hours. Immunofluorescence staining for NeuN, Ib1a, TLR4 and GRP78 in the hypothalamic paraventricular nucleus (PVN) was performed. TNF-α, TLR4 and GRP78 protein expression in the PVN were evaluated by western blot. Plasma norepinephrine levels were determined by ELISA. Acute LPS treatment increased HR and plasma norepinephrine concentration. It also decreased HR variability and high frequency (HF) components of HR variability, as well BrS. Acute LPS treatment increased TLR4 and TNF-α protein expression in the PVN. These hemodynamic and molecular effects were partially abrogated with TLR4 blocker or ER stress inhibitor pretreatment. In addition, immunofluorescence study showed that TLR4 is co-localized with GRP78in the neurons. Further inhibition of TLR4 or ER stress was able to attenuate the LPS-induced microglia activation. TLR4 signaling promotes autonomic dysfunction, inflammation and microglia activation, through neuronal ER stress, in the PVN.

  14. Attenuation of ventilation-induced diaphragm dysfunction through toll-like receptor 4 and nuclear factor-κB in a murine endotoxemia model.

    PubMed

    Li, Li-Fu; Liu, Yung-Yang; Chen, Ning-Hung; Chen, Yen-Huey; Huang, Chung-Chi; Kao, Kuo-Chin; Chang, Chih-Hao; Chuang, Li-Pang; Chiu, Li-Chung

    2018-06-20

    Mechanical ventilation (MV) is often used to maintain life in patients with sepsis and sepsis-related acute lung injury. However, controlled MV may cause diaphragm weakness due to muscle injury and atrophy, an effect termed ventilator-induced diaphragm dysfunction (VIDD). Toll-like receptor 4 (TLR4) and nuclear factor-κB (NF-κB) signaling pathways may elicit sepsis-related acute inflammatory responses and muscle protein degradation and mediate the pathogenic mechanisms of VIDD. However, the mechanisms regulating the interactions between VIDD and endotoxemia are unclear. We hypothesized that mechanical stretch with or without endotoxin treatment would augment diaphragmatic structural damage, the production of free radicals, muscle proteolysis, mitochondrial dysfunction, and autophagy of the diaphragm via the TLR4/NF-κB pathway. Male C57BL/6 mice, either wild-type or TLR4-deficient, aged between 6 and 8 weeks were exposed to MV (6 mL/kg or 10 mL/kg) with or without endotoxemia for 8 h. Nonventilated mice were used as controls. MV with endotoxemia aggravated VIDD, as demonstrated by the increases in the expression levels of TLR4, caspase-3, atrogin-1, muscle ring finger-1, and microtubule-associated protein light chain 3-II. In addition, increased NF-κB phosphorylation and oxidative loads, disorganized myofibrils, disrupted mitochondria, autophagy, and myonuclear apoptosis were also observed. Furthermore, MV with endotoxemia reduced P62 levels and diaphragm muscle fiber size (P < 0.05). Endotoxin-exacerbated VIDD was attenuated by pharmacologic inhibition with a NF-κB inhibitor or in TLR4-deficient mice (P < 0.05). Our data indicate that endotoxin-augmented MV-induced diaphragmatic injury occurs through the activation of the TLR4/NF-κB signaling pathway.

  15. Medicinal mushroom Lingzhi or Reishi, Ganoderma lucidum (W.Curt.:Fr.) P. Karst., beta-glucan induces Toll-like receptors and fails to induce inflammatory cytokines in NF-kappaB inhibitor-treated macrophages.

    PubMed

    Batbayar, Sainkhuu; Kim, Mi Jeong; Kim, Ha Won

    2011-01-01

    Beta-Glucan of medicinal Lingzhi or Reishi mushroom, Ganoderma lucidum (BGG), possesses immunostimulatory and anti-tumor activities. Innate immune cells are activated by the binding of beta-glucan to the dectin-1 receptor. The present study investigated the immunostimulating activities of BGG, including binding to dectin-1, secretion of cytokines and reactive oxygen species, and induction of Toll-like receptors (TLRs) in RAW264.7 mouse macrophages. Reverse transcription-polymerase chain reaction and flow cytometry were used for the cytokine and TLR analyses. A mouse inflammation antibody array was used for protein-level cytokine analysis. BGG bound to dectin-1 and induced RAW264.7 cell secretion of several cytokines, including granulocyte colony-stimulating factor, interleukin (IL)-6, regulated upon activation normal T cell expressed and secreted (RANTES), tissue inhibitor of metalloproteinase-1, and tumor necrosis factor-alpha. The secretion of these cytokines was further increased by the addition of lipopolysaccharide (LPS). BGG also induced both nitric oxide and inducible nitric oxide synthase (iNOS). Treatment with an inhibitor of nuclear factor-kappa B (NF-kappaB) reduced the induction of IL-1, IL-6, and iNOS in a concentration-dependent manner. Expressions of TLR2, TLR4, and TLR6 were increased by BGG treatment, and addition of LPS induced further induction of TLR4 and TLR6. Our result indicates that BGG induces macrophage secretion of inflammatory cytokines, which can be potentiated by the presence of LPS, likely by binding to dectin-1 and TLR-2/6 receptors, which activate NF-kappaB and prompt the secretion of cytokines.

  16. Toll-Like Receptor 4 Is an Essential Upstream Regulator of On-Time Parturition and Perinatal Viability in Mice

    PubMed Central

    Wahid, Hanan H.; Dorian, Camilla L.; Chin, Peck Yin; Hutchinson, Mark R.; Rice, Kenner C.; Olson, David M.; Moldenhauer, Lachlan M.

    2015-01-01

    An inflammatory response is instrumental in the physiological process of parturition but the upstream signals initiating inflammation are undefined. Because endogenous ligands for Toll-like receptor 4 (TLR4) are released in late gestation, we hypothesized that on-time labor requires TLR4 signaling, to trigger a cytokine and leukocyte response and accelerate the parturition cascade. In pregnant TLR4-deficient (Tlr4−/−) mice, average gestation length was extended by 13 hours and increased perinatal mortality was seen compared with wild-type controls. Quantification of cytokine and uterine activation gene expression showed that late gestation induction of Il1b, Il6, Il12b, and Tnf expression seen in control placenta and fetal membranes was disrupted in Tlr4−/− mice, and accompanied by a transient delay in expression of uterine activation genes, including prostaglandin F receptor, oxytocin receptor, and connexin-43. Leukocyte populations were altered before birth in TLR4-deficient females, with fewer neutrophils and macrophages in the placenta, and fewer dendritic cells and more regulatory T cells in the myometrium. Administration of TLR4 ligand lipopolysaccharide to pregnant wild-type mice induced cytokine expression and fetal loss, whereas Tlr4−/− pregnancies were protected. The small molecule TLR4 antagonist (+)-naloxone increased mean duration of gestation by 16 hours in wild-type mice. Collectively, these data demonstrate that TLR4 is a key upstream regulator of the inflammatory response acting to drive uterine activation and control the timing of labor. Because causal pathways for term and preterm labor converge with TLR4, interventions to manipulate TLR4 signaling may have therapeutic utility for women at risk of preterm labor, or in postterm pregnancy. PMID:26151355

  17. Analysis of Post-transcriptional Gene Regulation of Nod-Like Receptors via the 3'UTR.

    PubMed

    Haneklaus, Moritz

    2016-01-01

    Innate immune signaling is the front line of defense against pathogens, leading to an appropriate response of immune cells upon activation of their pattern recognition receptors (PRRs) by microbial products, such as Toll-like receptors (TLRs). Apart from transcriptional control, gene expression in the innate immune system is also highly regulated at the post-transcriptional level. miRNA or RNA-binding protein can bind to the 3' untranslated region (UTR) of target mRNAs and affect their mRNA stability and translation efficiency, which ultimately affects the amount of protein that is produced. In recent years, a new group of PRRs, the Nod-like receptors (NLR) have been discovered. They often cooperate with TLR signaling to induce potent inflammatory responses. Many NLRs can form inflammasomes, which facilitate the production of the potent pro-inflammatory cytokine IL-1β and other inflammatory mediators. In contrast to TLRs, the importance of post-transcriptional regulators in the context of inflammasomes has not been well defined. This chapter describes a series of experimental approaches to determine the effect of post-transcriptional regulation for a gene of interest using the best-studied NLR, NLRP3, as an example. To start investigating post-transcriptional regulation, 3'UTR luciferase experiments can be performed to test if regulatory sequences in the 3'UTR are functional. An RNA pull-down approach followed by mass spectrometry provides an unbiased assay to identify RNA-binding proteins that target the 3'UTR. Candidate binding proteins can then be further validated by RNA immunoprecipitation (RNA-IP), where the candidate protein is isolated using a specific antibody and bound mRNAs are analyzed by qPCR.

  18. PcToll2 positively regulates the expression of antimicrobial peptides by promoting PcATF4 translocation into the nucleus.

    PubMed

    Lan, Jiang-Feng; Zhao, Li-Juan; Wei, Shun; Wang, Yuan; Lin, Li; Li, Xin-Cang

    2016-11-01

    Drosophila Toll and mammalian Toll-like receptors (TLRs) are a family of evolutionarily conserved immune receptors that play a crucial role in the first-line defense against intruded pathogens. Activating transcription factor 4 (ATF4), a member of the ATF/CREB transcription factor family, is an important factor that participates in TLR signaling and other physiological processes. However, in crustaceans, whether ATF4 homologs were involved in TLR signaling remains unclear. In the current study, we identified a Toll homolog PcToll2 and a novel ATF4 homolog PcATF4 from Procambarus clarkii, and analyzed the likely regulatory activity of PcATF4 in PcToll2 signaling. The complete cDNA sequence of PcToll2 was 4175 bp long containing an open reading frame of 2820 bp encoding a 939-amino acid protein, and the cDNA sequence of PcATF4 was 2027 bp long with an open reading frame of 1296 bp encoding a 431-amino acid protein. PcToll2 and human TLR4 shared the high identity and they were grouped into a cluster. Furthermore, PcToll2 had a close relationship with other shrimp TLRs that possessed potential antibacterial activity. PcToll2 was highly expressed in the hemocytes, heart and gills, while PcATF4 mainly distributed in gills. Upon challenge with Vibrio parahemolyticus, PcToll2 and PcATF4 together with the antimicrobial peptides of ALF1 and ALF2 were significantly up-regulated in the hemocytes, and the PcATF4 was translocated into the nucleus. After PcToll2 silencing and challenge with Vibrio, the translocation of PcATF4 into the nucleus was inhibited and the expression of ALF1 and ALF2 was reduced, but the expression of PcDorsal and PcSTAT was not affected. Furthermore, after PcATF4 knockdown and challenge with or without Vibrio, the expression of ALF1 and ALF2 was also decreased while the expression of PcToll2 was upregulated. These results suggested that PcToll2 might regulate the expression of ALF1 and ALF2 by promoting the import of PcATF4, instead of the routine

  19. In silico analysis of Schmidtea mediterranea TIR domain-containing proteins.

    PubMed

    Tsoumtsa, Landry Laure; Sougoufora, Seynabou; Torre, Cedric; Lemichez, Emmanuel; Pontarotti, Pierre; Ghigo, Eric

    2018-09-01

    While genetic evidence points towards an absence of Toll-Like Receptors (TLRs) in Platyhelminthes, the Toll/IL-1 Receptor (TIR)-domains that drive the assembly of signalling complexes downstream TLR are present in these organisms. Here, we undertook the characterisation of the repertoire of TIR-domain containing proteins in Schmidtea mediterranea in order to gain valuable information on TLR evolution in metazoan. We report the presence of twenty proteins containing between one and two TIR domains. In addition, our phylogenetic-based reconstruction approach identified Smed-SARM and Smed-MyD88 as conserved TLR adaptors. Copyright © 2018 Elsevier Ltd. All rights reserved.

  20. Acemannan increases NF-κB/DNA binding and IL-6/-8 expression by selectively binding Toll-like receptor-5 in human gingival fibroblasts.

    PubMed

    Thunyakitpisal, Pasutha; Ruangpornvisuti, Vithaya; Kengkwasing, Pattrawadee; Chokboribal, Jaroenporn; Sangvanich, Polkit

    2017-04-01

    Acemannan, an acetylated polymannose from Aloe vera, has immunomodulatory effects. We investigated whether acemannan induces IL-6 and -8 expression and NF-κB/DNA binding in human gingival fibroblasts. IL-6 and -8 expression levels were assessed via RT-PCR and ELISA. The NF-κB p50/p65-DNA binding was determined. The structures of acemannan mono-pentamers and Toll-like receptor 5 (TLR5) were simulated. The binding energies between acemannan and TLR5 were identified. We found that acemannan significantly stimulated IL-6/-8 expression at both the mRNA and protein level and significantly increased p50/DNA binding. Preincubation with an anti-TLR5 neutralizing antibody abolished acemannan-induced IL-6/-8 expression and p50/DNA binding, and co-incubation of acemannan with Bay11-7082, a specific NF- κB inhibitor, abolished IL-6/-8 expression. The computer modeling indicated that monomeric/dimeric single stranded acemannan molecules interacted with the TLR5 flagellin recognition sites with a high binding affinity. We conclude that acemannan induces IL-6/-8 expression, and p50/DNA binding in gingival fibroblasts, at least partly, via a TLR5/NF-κB-dependent signaling pathway. Furthermore, acemannan selectively binds with TLR5 ectodomain flagellin recognition sites. Copyright © 2017 Elsevier Ltd. All rights reserved.