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.

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.

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

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

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.

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

Immune activation by medium-chain triglyceride-containing lipid emulsions is not modulated by n-3 lipids or toll-like receptor 4.

PubMed

Olthof, Evelyn D; Gülich, Alexandra F; Renne, Mike F; Landman, Sija; Joosten, Leo A B; Roelofs, Hennie M J; Wanten, Geert J A

2015-10-01

Saturated medium-chain triglycerides (MCT) as part of the parenteral lipid regimen (50% MCT and 50% long chain triglycerides (LCT)) activate the immune system in vitro. Fish oil (FO)-derived n-3 fatty acids (FA) inhibit saturated FA-induced immune activation via a toll-like receptor (TLR)-4 mediated mechanism. We hypothesized that effects of parenteral MCTs on immune cells involve TLR-4 signaling and that these effects are modulated by n-3 FA that are present in FO. To test this hypothesis we assessed effects of addition of various commercially available mixed parenteral lipid emulsions, n-3 FA and of TLR-4 inhibition on MCT-induced human immune cell activation by evaluation of the expression of leukocyte membrane activation markers and reactive oxygen species (ROS) production. All MCT-containing lipid emulsions activated leukocytes by inducing changes in expression of membrane markers and stimulus induced ROS production, whereas MCT-free lipid emulsions lacked this effect. Moreover, addition of n-3 FA to LCT/MCT did not prevent MCT-induced immune activation. TLR-4 inhibitors did not distinctly modulate MCT-induced changes in immune function. Taken together, these findings suggest that leukocyte activation by parenteral MCTs does not involve TLR-4 signaling and is not modulated by n-3 FA in FO-, but is exerted via different signaling pathways. Copyright © 2015 Elsevier Ltd. All rights reserved.

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.

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

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.

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

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.

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.

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.

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.

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.

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.

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

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.

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.

[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.

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

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.

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.

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

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.

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

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.

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.

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

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.

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.

MicroRNA-3148 modulates allelic expression of toll-like receptor 7 variant associated with systemic lupus erythematosus.

PubMed

Deng, Yun; Zhao, Jian; Sakurai, Daisuke; Kaufman, Kenneth M; Edberg, Jeffrey C; Kimberly, Robert P; Kamen, Diane L; Gilkeson, Gary S; Jacob, Chaim O; Scofield, R Hal; Langefeld, Carl D; Kelly, Jennifer A; Ramsey-Goldman, Rosalind; Petri, Michelle A; Reveille, John D; Vilá, Luis M; Alarcón, Graciela S; Vyse, Timothy J; Pons-Estel, Bernardo A; Freedman, Barry I; Gaffney, Patrick M; Sivils, Kathy Moser; James, Judith A; Gregersen, Peter K; Anaya, Juan-Manuel; Niewold, Timothy B; Merrill, Joan T; Criswell, Lindsey A; Stevens, Anne M; Boackle, Susan A; Cantor, Rita M; Chen, Weiling; Grossman, Jeniffer M; Hahn, Bevra H; Harley, John B; Alarcόn-Riquelme, Marta E; Brown, Elizabeth E; Tsao, Betty P

2013-01-01

We previously reported that the G allele of rs3853839 at 3'untranslated region (UTR) of Toll-like receptor 7 (TLR7) was associated with elevated transcript expression and increased risk for systemic lupus erythematosus (SLE) in 9,274 Eastern Asians [P = 6.5×10(-10), odds ratio (OR) (95%CI) = 1.27 (1.17-1.36)]. Here, we conducted trans-ancestral fine-mapping in 13,339 subjects including European Americans, African Americans, and Amerindian/Hispanics and confirmed rs3853839 as the only variant within the TLR7-TLR8 region exhibiting consistent and independent association with SLE (Pmeta = 7.5×10(-11), OR = 1.24 [1.18-1.34]). The risk G allele was associated with significantly increased levels of TLR7 mRNA and protein in peripheral blood mononuclear cells (PBMCs) and elevated luciferase activity of reporter gene in transfected cells. TLR7 3'UTR sequence bearing the non-risk C allele of rs3853839 matches a predicted binding site of microRNA-3148 (miR-3148), suggesting that this microRNA may regulate TLR7 expression. Indeed, miR-3148 levels were inversely correlated with TLR7 transcript levels in PBMCs from SLE patients and controls (R(2) = 0.255, P = 0.001). Overexpression of miR-3148 in HEK-293 cells led to significant dose-dependent decrease in luciferase activity for construct driven by TLR7 3'UTR segment bearing the C allele (P = 0.0003). Compared with the G-allele construct, the C-allele construct showed greater than two-fold reduction of luciferase activity in the presence of miR-3148. Reduced modulation by miR-3148 conferred slower degradation of the risk G-allele containing TLR7 transcripts, resulting in elevated levels of gene products. These data establish rs3853839 of TLR7 as a shared risk variant of SLE in 22,613 subjects of Asian, EA, AA, and Amerindian/Hispanic ancestries (Pmeta  = 2.0×10(-19), OR = 1.25 [1.20-1.32]), which confers allelic effect on transcript turnover via differential binding to the epigenetic factor

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

Inhibitory effects of dynorphin 3-14 on the lipopolysaccharide-induced toll-like receptor 4 signalling pathway.

PubMed

Rahiman, Siti Sarah Fazalul; Morgan, Michael; Gray, Paul; Shaw, Paul Nicholas; Cabot, Peter John

2017-04-01

Dynorphin 1-17 (DYN 1-17) is biotransformed rapidly to a range of fragments in rodent inflamed tissue with dynorphin 3-14 (DYN 3-14) being the most stable and prevalent. DYN 1-17 has been shown previously to be involved in the regulation of inflammatory response following tissue injury, in which the biotransformation fragments of DYN 1-17 may possess similar features. This study investigated the effects of DYN 3-14 on lipopolysaccharide (LPS)-induced nuclear factor-kappaB/p65 (NF-κB/p65) nuclear translocation and the release of pro-inflammatory cytokines interleukin-1beta (IL-1β) and tumor necrosis factor-alpha (TNF-α) in differentiated THP-1 cells. Treatment with DYN 3-14 (10nM) resulted in 35% inhibition of the LPS-induced nuclear translocation of NF-κB/p65. Furthermore, DYN 3-14 modulated both IL-1β and TNF-α release; inhibiting IL-1β and paradoxically augmenting TNF-α release in a concentration-independent manner. A number of opioids have been implicated in the modulation of the toll-like receptor 4 (TLR4), highlighting the complexity of their immunomodulatory effects. To determine whether DYN 3-14 modulates TLR4, HEK-Blue™ - hTLR4 cells were stimulated with LPS in the presence of DYN 3-14. DYN 3-14 (10μM) inhibited TLR4 activation in a concentration-dependent fashion by suppressing the LPS signals around 300-fold lower than LPS-RS, a potent TLR4 antagonist. These findings indicate that DYN 3-14 is a potential TLR4 antagonist that alters cellular signaling in response to LPS and cytokine release, implicating a role for biotransformed endogenous opioid peptides in immunomodulation. Copyright © 2017 Elsevier Inc. All rights reserved.

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

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.

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

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...

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.

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

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.

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

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.

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

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...

[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.

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

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.

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.

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.

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.

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.

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

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.

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.

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.

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

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

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

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

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.

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...

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

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

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

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

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.

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

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

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

Toll-like receptor 4 polymorphisms and their haplotypes modulate the risk of developing diabetic retinopathy in type 2 diabetes patients

PubMed Central

Singh, Kanhaiya; Kant, Shri; Singh, Vivek Kumar; Agrawal, Neeraj K.; Gupta, Sanjeev K.

2014-01-01

Purpose Persistent inflammation and impaired neovascularization in type 2 diabetes mellitus (T2DM) patients may lead to development of macro- and microvascular complications. Diabetic retinopathy (DR) is one of the secondary microvascular complications of T2DM. Improper activation of the innate immune system may be an important contributor in the pathophysiology of DR. Toll-like receptor 4 (TLR4) is an important mediator of innate immunity, and genetic alterations in TLR4 support inflammation in the hyperglycemic condition. The present work was designed to investigate whether the TLR4 single nucleotide polymorphisms (SNPs) rs4986790, rs4986791, rs10759931, rs1927911, and rs1927914 are associated with DR in a north Indian population. Methods The study group of 698 individuals (128 DR, 250 T2DM, 320 controls) was genotyped by PCR-RFLP. Haplotype and linkage disequilibrium between SNPs were determined using Haploview software. Results Combined risk genotypes of TLR4 SNPs rs10759931 (odds ratio [OR] 1.50, p = 0.05) and rs1927914 (OR 1.48, p = 0.05) were found to be significantly associated with pathogenesis of DR. A total of 14 haplotypes with frequency >1% were obtained using Haploview software. Haplotypes ACATC (37.5%) and ACATT (14.8%) were the two most common haplotypes obtained. Conclusions Results of the present case-control study that included 698 north Indian subjects suggested that TLR4 SNPs rs10759931 and rs1927914 modulate the risk of DR in T2DM cases. Association analysis using haplotypes showed none of the haplotypes were associated with either susceptibility or resistance to DR in a north Indian population. PMID:24883015

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.

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.

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.

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.

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.

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.

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.

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

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.

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.

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

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.

miR-958 inhibits Toll signaling and Drosomycin expression via direct targeting of Toll and Dif in Drosophila melanogaster.

PubMed

Li, Shengjie; Li, Yao; Shen, Li; Jin, Ping; Chen, Liming; Ma, Fei

2017-02-01

Drosophila melanogaster is widely used as a model system to study innate immunity and signaling pathways related to innate immunity, including the Toll signaling pathway. Although this pathway is well studied, the precise mechanisms of posttranscriptional regulation of key components of the Toll signaling pathway by microRNAs (miRNAs) remain obscure. In this study, we used an in silico strategy in combination with the Gal80 ts -Gal4 driver system to identify microRNA-958 (miR-958) as a candidate Toll pathway regulating miRNA in Drosophila We report that overexpression of miR-958 significantly reduces the expression of Drosomycin, a key antimicrobial peptide involved in Toll signaling and the innate immune response. We further demonstrate in vitro and in vivo that miR-958 targets the Toll and Dif genes, key components of the Toll signaling pathway, to negatively regulate Drosomycin expression. In addition, a miR-958 sponge rescued the expression of Toll and Dif, resulting in increased expression of Drosomycin. These results, not only revealed a novel function and modulation pattern of miR-958, but also provided a new insight into the underlying molecular mechanisms of Toll signaling in regulation of innate immunity. Copyright © 2017 the American Physiological Society.

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.

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

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

Tissue factor and Toll-like receptor (TLR)4 in hyperglycaemia-hyperinsulinaemia. Effects in healthy subjects, and type 1 and type 2 diabetes mellitus.

PubMed

Singh, Anamika; Boden, Guenther; Rao, A Koneti

2015-04-01

Diabetes mellitus (DM) patients have an increased incidence of cardiovascular events. Blood tissue factor-procoagulant activity (TF-PCA), the initiating mechanism for blood coagulation, is elevated in DM. We have shown that hyperglycaemia (HG), hyperinsulinaemia (HI) and combined HG+HI (induced using 24-hour infusion clamps) increases TF-PCA in healthy and type 2 DM (T2DM) subjects, but not in type 1 DM (T1DM) subjects. The mechanisms for this are unknown. DM patients have elevated plasma lipopolysaccharide (LPS), a toll-like receptor (TLR) 4 ligand. We postulated that TLR4 plays a role in modulating TF levels. We studied the effect of HG+HI on TLR4 and TF-PCA in vivo during 24-hour HG+HI infusion clamps in healthy subjects, and T1DM and T2DM subjects, and in vitro in blood. In vivo, in healthy subjects, 24-hour HG + HI infusion increased TLR4 six-fold, which correlated with TF-PCA (r= 0.91, p<0.0001). T2DM patients showed smaller increases in both. In T1DM subjects, TLR4 declined (50%, p<0.05) and correlated with TF-PCA (r=0.55; p<0.05). In vitro, HG (200 mg/dl added glucose) and HI (1-100 nM added insulin) increased TF-PCA in healthy subjects (~2-fold, 2-4 hours). Insulin inhibited by ~30% LPS-induced increase in TF-PCA and high glucose reversed it. TLR4 levels paralleled TF-PCA (r=0.71, p<0.0001); HG and HI increased TLR4 and insulin inhibited LPS-induced TLR4 increase. This is first evidence that even in healthy subjects, HG of short duration increases TLR4 and TF-PCA, key players in inflammation and thrombosis. TLR4-TF interplay is strikingly different in non-diabetic, T1DM and T2DM subjects.

Tissue Factor and Toll Like Receptor (TLR)4 in Hyperglycemia-Hyperinsulinemia: Effects in Healthy Subjects, and Type 1 and Type 2 Diabetes Mellitus

PubMed Central

Singh, Anamika; Boden, Guenther; Rao, A. Koneti

2015-01-01

SUMMARY Background Diabetes mellitus (DM) patients have increased cardiovascular events. Blood tissue factor-procoagulant activity (TF-PCA), the initiating mechanism for blood coagulation, is elevated in DM. We have shown that hyperglycemia (HG), hyperinsulinemia (HI) and combined HG+HI (induced using 24 hr infusion clamps) increases TF-PCA in healthy and T2DM subjects, but not in T1DM subjects. The mechanisms for this are unknown. DM patients have elevated plasma lipopolysaccharide (LPS), a toll-like receptor (TLR) 4 ligand. We postulated that TLR4 plays a role in modulating TF levels. Objectives and Methods We studied the effect of HG+HI on TLR4 and TF-PCA in vivo during 24 hr HG+HI infusion clamps in healthy subjects, and T1DM and T2DM subjects, and in vitro in blood. Results In vivo, in healthy subjects, 24 hr HG + HI infusion increased TLR4 6-fold, which correlated with TF-PCA (r= 0.91, p<0.0001). T2DM patients showed smaller increases in both. In T1DM subjects, TLR4 declined (50%, p<0.05) and correlated with TF-PCA (r=0.55; p<0.05). In vitro, HG (200 mg/dl added glucose) and HI (1-100 nM added insulin) increased TF-PCA in healthy subjects (~2-fold, 2-4 hr). Insulin inhibited by ~30% LPS-induced increase in TF-PCA and high glucose reversed it. TLR4 levels paralleled TF-PCA (r=0.71, p<0.0001); HG and HI increased TLR4 and insulin inhibited LPS-induced TLR4 increase. Conclusions This is first evidence that even in healthy subjects, HG of short duration increases TLR4 and TF-PCA, key players in inflammation and thrombosis. TLR4-TF interplay is strikingly different in non-diabetic, T1DM and T2DM subjects. PMID:25653143

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.

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.

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

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.

Geometric design and operational factors that impact truck use of toll roads.

DOT National Transportation Integrated Search

2010-09-01

This purpose of this project was to identify the potential factors that could impact truck use of toll roads or : managed lanes. The researchers outlined the trucking and freight industry needs through synthesis of : existing literature. Identificati...

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

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.

Double blind clinical trial in a series of 115 patients with seborrheic dermatitis: prevention of relapses using a topical modulator of Toll like receptor 2.

PubMed

Ionescu, M A; Baroni, A; Brambilla, L; Cannavò, S P; Cristaudo, A; Vedove, C Dalle; Frasca, M; Girolomoni, G; Gnecchi, L; Peris, K; Trifirò, C; Matta, A M; Robert, G

2011-06-01

Seborrheic dermatitis is a chronic inflammatory disease aggravated by Malassezia species. Toll-like receptors (TLR) are part of innate immune system that can be activated by yeasts. Previous studies showed that an association of Umbelliferae extract with a lipid (TLR2-Regul™) decreases the IL-8 expression in human skin in contact with M. furfur. The aim of this study was to assess the activity of a topical formulated with TLR2-Regul™ in the prevention of seborrheic dermatitis (SD) relapses. Immune-competent SD adult patients were treated for SD (topical imidazoles or steroids). Cleared patients were randomized and received a topical containing TLR2-Regul™ (A) or its vehicle (B). Erythema, scales and pruritus were assessed during two months. The study included 115 patients, mean age 43.4, sex ratio m/f 1.5. At week 4 the relapse rate was 26% (N.=15) in group A and 43% (N.=25) in group B. At W8 the relapse rate was 21% (N.=12) in group A and 40% (N.=23) (P=0.0309). In this series of 115 adults with seborrheic dermatitis, patients treated with a topical containing TLR-Regul™ showed a significantly less relapse rate compared with the excipient group (P<0.05). TLR modulation could represent a new therapeutic approach in the prevention of seborrheic dermatitis relapses.

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

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.

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...

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.

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

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.

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

Comprehensive Logic Based Analyses of Toll-Like Receptor 4 Signal Transduction Pathway

PubMed Central

Padwal, Mahesh Kumar; Sarma, Uddipan; Saha, Bhaskar

2014-01-01

Among the 13 TLRs in the vertebrate systems, only TLR4 utilizes both Myeloid differentiation factor 88 (MyD88) and Toll/Interleukin-1 receptor (TIR)-domain-containing adapter interferon-β-inducing Factor (TRIF) adaptors to transduce signals triggering host-protective immune responses. Earlier studies on the pathway combined various experimental data in the form of one comprehensive map of TLR signaling. But in the absence of adequate kinetic parameters quantitative mathematical models that reveal emerging systems level properties and dynamic inter-regulation among the kinases/phosphatases of the TLR4 network are not yet available. So, here we used reaction stoichiometry-based and parameter independent logical modeling formalism to build the TLR4 signaling network model that captured the feedback regulations, interdependencies between signaling kinases and phosphatases and the outcome of simulated infections. The analyses of the TLR4 signaling network revealed 360 feedback loops, 157 negative and 203 positive; of which, 334 loops had the phosphatase PP1 as an essential component. The network elements' interdependency (positive or negative dependencies) in perturbation conditions such as the phosphatase knockout conditions revealed interdependencies between the dual-specific phosphatases MKP-1 and MKP-3 and the kinases in MAPK modules and the role of PP2A in the auto-regulation of Calmodulin kinase-II. Our simulations under the specific kinase or phosphatase gene-deficiency or inhibition conditions corroborated with several previously reported experimental data. The simulations to mimic Yersinia pestis and E. coli infections identified the key perturbation in the network and potential drug targets. Thus, our analyses of TLR4 signaling highlights the role of phosphatases as key regulatory factors in determining the global interdependencies among the network elements; uncovers novel signaling connections; identifies potential drug targets for infections. PMID:24699232

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

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

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

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.

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

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.

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...

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

Mannan-binding lectin directly interacts with Toll-like receptor 4 and suppresses lipopolysaccharide-induced inflammatory cytokine secretion from THP-1 cells

PubMed Central

Wang, Mingyong; Chen, Yue; Zhang, Yani; Zhang, Liyun; Lu, Xiao; Chen, Zhengliang

2011-01-01

Mannan-binding lectin (MBL) plays a key role in the lectin pathway of complement activation and can influence cytokine expression. Toll-like receptor 4 (TLR4) is expressed extensively and has been demonstrated to be involved in lipopolysaccharide (LPS)-induced signaling. We first sought to determine whether MBL exposure could modulate LPS-induced inflammatory cytokine secretion and nuclear factor-κB (NF-κB) activity by using the monocytoid cell line THP-1. We then investigated the possible mechanisms underlying any observed regulatory effect. Using ELISA and reverse transcriptase polymerase chain reaction (RT-PCR) analysis, we found that at both the protein and mRNA levels, treatment with MBL suppresses LPS-induced tumor-necrosis factor (TNF)-α and IL-12 production in THP-1 cells. An electrophoretic mobility shift assay and western blot analysis revealed that MBL treatment can inhibit LPS-induced NF-κB DNA binding and translocation in THP-1 cells. While the binding of MBL to THP-1 cells was evident at physiological calcium concentrations, this binding occurred optimally in response to supraphysiological calcium concentrations. This binding can be partly inhibited by treatment with either a soluble form of recombinant TLR4 extracellular domain or anti-TLR4 monoclonal antibody (HTA125). Activation of THP-1 cells by LPS treatment resulted in increased MBL binding. We also observed that MBL could directly bind to the extracellular domain of TLR4 in a dose-dependent manner, and this interaction could attenuate the binding of LPS to cell surfaces. Taken together, these data suggest that MBL may affect cytokine expression through modulation of LPS-/TLR-signaling pathways. These findings suggest that MBL may play an important role in both immune regulation and the signaling pathways involved in cytokine networks. PMID:21383675

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.

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.

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.

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.

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

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

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.

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.

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.

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.

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.

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

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

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

Immunobiotic Lactobacillus jensenii Elicits Anti-Inflammatory Activity in Porcine Intestinal Epithelial Cells by Modulating Negative Regulators of the Toll-Like Receptor Signaling Pathway

PubMed Central

Shimazu, Tomoyuki; Villena, Julio; Tohno, Masanori; Fujie, Hitomi; Hosoya, Shoichi; Shimosato, Takeshi; Aso, Hisashi; Suda, Yoshihito; Kawai, Yasushi; Saito, Tadao; Makino, Seiya; Ikegami, Shuji; Itoh, Hiroyuki

2012-01-01

The effect of Lactobacillus jensenii TL2937 on the inflammatory immune response triggered by enterotoxigenic Escherichia coli (ETEC) and lipopolysaccharide (LPS) in a porcine intestinal epitheliocyte cell line (PIE cells) was evaluated. Challenges with ETEC or LPS elicited Toll-like receptor 4 (TLR4)-mediated inflammatory responses in cultured PIE cells, indicating that our cell line may be useful for studying inflammation in the guts of weaning piglets. In addition, we demonstrated that L. jensenii TL2937 attenuated the expression of proinflammatory cytokines and chemokines caused by ETEC or LPS challenge by downregulating TLR4-dependent nuclear factorκB (NF-κB) and mitogen-activated protein kinase (MAPK) activation. Furthermore, we demonstrated that L. jensenii TL2937 stimulation of PIE cells upregulated three negative regulators of TLRs: A20, Bcl-3, and MKP-1, deepening the understanding of an immunobiotic mechanism of action. L. jensenii TL2937-mediated induction of negative regulators of TLRs would have a substantial physiological impact on homeostasis in PIE cells, because excessive TLR inflammatory signaling would be downregulated. These results indicated that PIE cells can be used to study the mechanisms involved in the protective activity of immunobiotics against intestinal inflammatory damage and may provide useful information for the development of new immunologically functional feeds that help to prevent inflammatory intestinal disorders, including weaning-associated intestinal inflammation. PMID:22083706

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.

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.

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

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

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.

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.

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.

PcToll3 was involved in anti-Vibrio response by regulating the expression of antimicrobial peptides in red swamp crayfish, Procambarus clarkii.

PubMed

Lan, Jiang-Feng; Wei, Shun; Wang, Yu-Qing; Dai, Yun-Jia; Tu, Jia-Gang; Zhao, Li-Juan; Li, Xin-Cang; Qin, Qi-Wei; Chen, Nan; Lin, Li

2016-10-01

Tolls and Toll-like receptors (TLRs) play an important role in host immune defenses by regulating the expression of antimicrobial peptides (AMPs) and cytokines, but the functional differences of crustacean Tolls from Drosophila Tolls or Mammal TLRs are largely unknown. A novel Toll receptor, named PcToll3, was identified from red swamp crayfish, Procambarus clarkii. It was widely expressed in all detected tissues, and its transcript in hemocytes was up-regulated at 12 h after Vibrio parahemolyticus (Vibrio) injection or at 24 h post white spot syndrome virus (WSSV) challenge. After knockdown of PcToll3, the activity of bacterial clearance was inhibited, and the expression levels of AMPs including Crustin1 (Cru1), Anti-lippopolysaccharide factor 1 (ALF1), and Lysozymes1 (Lys1), which could be up-regulated by Vibrio, were all affected. Meanwhile, PcToll3 silencing influenced the expression of myeloid differentiation factor 88 (PcMyd88), tumor necrosis factor-associated factor 6 (PcTRAF6), and PcDorsal, which were the counterparts of Drosophila Toll signaling pathway. Interestingly, PcToll3 silencing inhibited translocation of PcDorsal from cytoplasm to nucleus. Furthermore, the knockdown of PcDorsal also impaired the expression of AMPs after Vibrio challenge. Hence, we concluded that, besides participating in antiviral immunity, PcToll3 might also regulate the expression of Cru1 and Lys1 to participate in anti-Vibrio immune responses by promoting PcDorsal translocation into nucleus. Copyright © 2016 Elsevier Ltd. All rights reserved.

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.

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

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.

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...

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

Executive report : toll roads, toll rates, and driver behavior.

DOT National Transportation Integrated Search

2012-12-01

State and federal research has examined toll roads and attempted to identify methods to make toll roads a more attractive option for drivers. Researchers examined various views of toll road transactions and concluded: : Truckers and trucking comp...

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

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.

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

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.

Occupational Noise Exposure among Toll Tellers at Toll Plaza in Malaysia

NASA Astrophysics Data System (ADS)

Azmi, Sharifah Nadya Syed; Dawal, Siti Zawiah Md; Ya, Tuan Mohammad Yusoff Shah Tuan; Saidin, Hamidi

2010-10-01

Toll tellers working at toll plaza have potential of exposure to high noise from the vehicles especially for the peak level of sound emitted by the heavy vehicles. However, occupational exposures in this workplace have not been adequately characterized and identified. Occupational noise exposure among toll tellers at toll plaza was assessed using Sound Level Meter, Noise Dosimeter and through questionnaire survey. These data were combined to estimate the work shift exposure level and health impacts to the toll tellers by using statistical analysis. Noise Dosimeter microphone was located at the hearing zone of the toll teller which working inside the toll booth and full-period measurements were collected for each work shift. The measurements were taken at 20 toll booths from 6.00 am to 2.00 pm for 5 days. 71 respondents participated in the survey to identify the symptoms of noise induced hearing loss and other health related problems among toll tellers. Results of this study indicated that occupational noise exposure among toll tellers for Mean Continuous Equivalent Level, Leq was 79.2±1.4 dB(A), Mean Maximum Level, Lmax was 107.8±3.6 dB(A) and Mean Peak Level, Lpeak was 136.6±9.9 dB. The Peak Level reported statistically significantly at 140 dB, the level of TLV recommended by ACGIH. The research findings indicated that the primary risk exposure to toll tellers comes from noise that emitted from heavy vehicles. Most of the toll tellers show symptoms of noise induced hearing loss and annoyed by the sources of noise at the toll plaza.

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.

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

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

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.

Toll-like receptor (TLR)-1/2 triggering of multiple myeloma cells modulates their adhesion to bone marrow stromal cells and enhances bortezomib-induced apoptosis.

PubMed

Abdi, Jahangir; Mutis, Tuna; Garssen, Johan; Redegeld, Frank A

2014-01-01

In multiple myeloma (MM), the malignant plasma cells usually localize to the bone marrow where they develop drug resistance due to adhesion to stromal cells and various environmental signals. Hence, modulation of this interaction is expected to influence drug sensitivity of MM cells. Toll-like receptor (TLR) ligands have displayed heterogeneous effects on B-cell malignancies and also on MM cells in a few recent studies, but effects on adhesion and drug sensitivity of myeloma cells in the context of bone marrow stromal cells (BMSCs) have never been investigated. In the present study, we explored the modulatory effects of TLR1/2 ligand (Pam3CSK4) on adhesion of human myeloma cells to BMSCs. It is shown that TLR1/2 triggering has opposite effects in different HMCLs on their adhesion to BMSCs. Fravel, L363, UM-6, UM-9 and U266 showed increased adhesion to BMSC in parallel with an increased surface expression of integrin molecules α4 and αVβ3. OPM-1, OPM-2 and NCI-H929 showed a dose-dependent decrease in adhesion upon TLR activation following a downregulation of β7 integrin expression. Importantly, TLR1/2 triggering increased cytotoxic and apoptotic effects of bortezomib in myeloma cells independent of the effect on stromal cell adhesion. Moreover, the apoptosis-enhancing effect of Pam3CSK4 paralleled induction of cleaved caspase-3 protein in FACS analysis suggesting a caspase-dependent mechanism. Our findings uncover a novel role of TLR activation in MM cells in the context of bone marrow microenvironment. Stimulation of TLR1/2 bypasses the protective shield of BMSCs and may be an interesting strategy to enhance drug sensitivity of multiple myeloma cells.

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.

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

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.

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.

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.

Lipid A structural modifications in extreme conditions and identification of unique modifying enzymes to define the Toll-like receptor 4 structure-activity relationship.

PubMed

Scott, Alison J; Oyler, Benjamin L; Goodlett, David R; Ernst, Robert K

2017-11-01

Strategies utilizing Toll-like receptor 4 (TLR4) agonists for treatment of cancer, infectious diseases, and other targets report promising results. Potent TLR4 antagonists are also gaining attention as therapeutic leads. Though some principles for TLR4 modulation by lipid A have been described, a thorough understanding of the structure-activity relationship (SAR) is lacking. Only through a complete definition of lipid A-TLR4 SAR is it possible to predict TLR4 signaling effects of discrete lipid A structures, rendering them more pharmacologically relevant. A limited 'toolbox' of lipid A-modifying enzymes has been defined and is largely composed of enzymes from mesophile human and zoonotic pathogens. Expansion of this 'toolbox' will result from extending the search into lipid A biosynthesis and modification by bacteria living at the extremes. Here, we review the fundamentals of lipid A structure, advances in lipid A uses in TLR4 modulation, and the search for novel lipid A-modifying systems in extremophile bacteria. This article is part of a Special Issue entitled: Bacterial Lipids edited by Russell E. Bishop. Copyright © 2017 Elsevier B.V. All rights reserved.

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

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.

Chronic Toll-like receptor 4 stimulation in skin induces inflammation, macrophage activation, transforming growth factor beta signature gene expression, and fibrosis

PubMed Central

2014-01-01

Introduction The crucial role of innate immunity in the pathogenesis of systemic sclerosis (SSc) is well established, and in the past few years the hypothesis that Toll-like receptor 4 (TLR4) activation induced by endogenous ligands is involved in fibrogenesis has been supported by several studies on skin, liver, and kidney fibrosis. These findings suggest that TLR4 activation can enhance transforming growth factor beta (TGF-β) signaling, providing a potential mechanism for TLR4/Myeloid differentiation factor 88 (MyD88)-dependent fibrosis. Methods The expression of TLR4, CD14 and MD2 genes was analyzed by real-time polymerase chain reaction from skin biopsies of 24 patients with diffuse cutaneous SSc. In order to investigate the effects of the chronic skin exposure to endotoxin (Lipopolysaccharide (LPS)) in vivo we examined the expression of inflammation, TGF-β signaling and cellular markers genes by nanostring. We also identified cellular subsets by immunohistochemistry and flow cytometry. Results We found that TLR4 and its co-receptors, MD2 and CD14, are over-expressed in lesional skin from patients with diffuse cutaneous SSc, and correlate significantly with progressive or regressive skin disease as assessed by the Delta Modified Rodnan Skin Score. In vivo, a model of chronic dermal LPS exposure showed overexpression of proinflammatory chemokines, recruitment and activation of macrophages, and upregulation of TGF-β signature genes. Conclusions We delineated the role of MyD88 as necessary for the induction not only for the early phase of inflammation, but also for pro-fibrotic gene expression via activation of macrophages. Chronic LPS exposure might be a model of early stage of SSc when inflammation and macrophage activation are important pathological features of the disease, supporting a role for innate immune activation in SSc skin fibrosis. PMID:24984848

Chronic Toll-like receptor 4 stimulation in skin induces inflammation, macrophage activation, transforming growth factor beta signature gene expression, and fibrosis.

PubMed

Stifano, Giuseppina; Affandi, Alsya J; Mathes, Allison L; Rice, Lisa M; Nakerakanti, Sashidhar; Nazari, Banafsheh; Lee, Jungeun; Christmann, Romy B; Lafyatis, Robert

2014-07-01

The crucial role of innate immunity in the pathogenesis of systemic sclerosis (SSc) is well established, and in the past few years the hypothesis that Toll-like receptor 4 (TLR4) activation induced by endogenous ligands is involved in fibrogenesis has been supported by several studies on skin, liver, and kidney fibrosis. These findings suggest that TLR4 activation can enhance transforming growth factor beta (TGF-β) signaling, providing a potential mechanism for TLR4/Myeloid differentiation factor 88 (MyD88)-dependent fibrosis. The expression of TLR4, CD14 and MD2 genes was analyzed by real-time polymerase chain reaction from skin biopsies of 24 patients with diffuse cutaneous SSc. In order to investigate the effects of the chronic skin exposure to endotoxin (Lipopolysaccharide (LPS)) in vivo we examined the expression of inflammation, TGF-β signaling and cellular markers genes by nanostring. We also identified cellular subsets by immunohistochemistry and flow cytometry. We found that TLR4 and its co-receptors, MD2 and CD14, are over-expressed in lesional skin from patients with diffuse cutaneous SSc, and correlate significantly with progressive or regressive skin disease as assessed by the Delta Modified Rodnan Skin Score. In vivo, a model of chronic dermal LPS exposure showed overexpression of proinflammatory chemokines, recruitment and activation of macrophages, and upregulation of TGF-β signature genes. We delineated the role of MyD88 as necessary for the induction not only for the early phase of inflammation, but also for pro-fibrotic gene expression via activation of macrophages. Chronic LPS exposure might be a model of early stage of SSc when inflammation and macrophage activation are important pathological features of the disease, supporting a role for innate immune activation in SSc skin fibrosis.

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

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

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.

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

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.

Conventional and Non-Conventional Drosophila Toll Signaling

PubMed Central

Lindsay, Scott A.; Wasserman, Steven A.

2013-01-01

The discovery of Toll in Drosophila and of the remarkable conservation in pathway composition and organization catalyzed a transformation in our understanding of innate immune recognition and response. At the center of that picture is a cascade of interactions in which specific microbial cues activate Toll receptors, which then transmit signals driving transcription factor nuclear localization and activity. Experiments gave substance to the vision of pattern recognition receptors, linked phenomena in development, gene regulation, and immunity into a coherent whole, and revealed a rich set of variations for identifying non-self and responding effectively. More recently, research in Drosophila has illuminated the positive and negative regulation of Toll activation, the organization of signaling events at and beneath membranes, the sorting of information flow, and the existence of non-conventional signaling via Toll-related receptors. Here, we provide an overview of the Toll pathway of flies and highlight these ongoing realms of research. PMID:23632253

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.

Exogenous oxidants activate nuclear factor kappa B through Toll-like receptor 4 stimulation to maintain inflammatory phenotype in macrophage.

PubMed

Zhang, Yan; Igwe, Orisa J

2018-01-01

Disturbances in redox equilibrium in tissue can lead to inflammatory state, which is a mediatory factor in many human diseases. The mechanism(s) by which exogenous oxidants may activate an inflammatory response is not fully understood. Emerging evidence suggests that oxidant-induced Toll-like receptor 4 (TLR4) activation plays a major role in "sterile" inflammation. In the present study, we used murine macrophage RAW-Blue cells, which are chromosomally integrated with secreted embryonic alkaline phosphatase (SEAP) inducible by NF-κB. We confirmed the expression of TLR4 mRNA and protein in RAW-Blue cells by RT-PCR and Western blot, respectively. We showed that oxidants increased intracellular reactive oxygen species production and lipid peroxidation, which resulted in decreased intracellular total antioxidant capacity. Consistent with the actions of TLR4-specific agonist LPS-EK, exogenous oxidants increased transcriptional activity of NF-κB p65 with subsequent release of NF-κB reporter gene SEAP. These effects were blocked by pretreatment with TLR4 neutralizing pAb and TLR4 signaling inhibitor CLI-095. In addition, oxidants decreased the expression of IκBα with enhanced phosphorylation at the Tyr42 residue. Finally, oxidants and LPS-EK increased TNFα production, but did not affect IL-10 production, which may cause imbalance between pro- and anti-inflammatory processes, which CLI-095 inhibited. For biological relevance, we confirmed that oxidants increased release of TNFα and IL-6 in primary macrophages derived from TLR4-WT and TLR4-KO mice. Our results support the involvement of TLR4 mediated oxidant-induced inflammatory phenotype through NF-κB activation in macrophages. Thus exogenous oxidants may play a role in activating inflammatory phenotypes that propagate and maintain chronic disease states. Copyright © 2017 Elsevier Inc. All rights reserved.

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.

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.

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.

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.

The Toll-Dorsal Pathway Is Required for Resistance to Viral Oral Infection in Drosophila

PubMed Central

Ferreira, Álvaro Gil; Naylor, Huw; Esteves, Sara Santana; Pais, Inês Silva; Martins, Nelson Eduardo; Teixeira, Luis

2014-01-01

Pathogen entry route can have a strong impact on the result of microbial infections in different hosts, including insects. Drosophila melanogaster has been a successful model system to study the immune response to systemic viral infection. Here we investigate the role of the Toll pathway in resistance to oral viral infection in D. melanogaster. We show that several Toll pathway components, including Spätzle, Toll, Pelle and the NF-kB-like transcription factor Dorsal, are required to resist oral infection with Drosophila C virus. Furthermore, in the fat body Dorsal is translocated from the cytoplasm to the nucleus and a Toll pathway target gene reporter is upregulated in response to Drosophila C Virus infection. This pathway also mediates resistance to several other RNA viruses (Cricket paralysis virus, Flock House virus, and Nora virus). Compared with control, viral titres are highly increased in Toll pathway mutants. The role of the Toll pathway in resistance to viruses in D. melanogaster is restricted to oral infection since we do not observe a phenotype associated with systemic infection. We also show that Wolbachia and other Drosophila-associated microbiota do not interact with the Toll pathway-mediated resistance to oral infection. We therefore identify the Toll pathway as a new general inducible pathway that mediates strong resistance to viruses with a route-specific role. These results contribute to a better understanding of viral oral infection resistance in insects, which is particularly relevant in the context of transmission of arboviruses by insect vectors. PMID:25473839

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.

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.

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.

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.

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.

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.

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

Rational Design of a New Class of Toll-Like Receptor 4 (TLR4) Tryptamine Related Agonists by Means of the Structure- and Ligand-Based Virtual Screening for Vaccine Adjuvant Discovery.

PubMed

Honegr, Jan; Dolezal, Rafael; Malinak, David; Benkova, Marketa; Soukup, Ondrej; Almeida, Joyce S F D de; Franca, Tanos C C; Kuca, Kamil; Prymula, Roman

2018-01-04

In order to identify novel lead structures for human toll-like receptor 4 ( h TLR4) modulation virtual high throughput screening by a peta-flops-scale supercomputer has been performed. Based on the in silico studies, a series of 12 compounds related to tryptamine was rationally designed to retain suitable molecular geometry for interaction with the h TLR4 binding site as well as to satisfy general principles of drug-likeness. The proposed compounds were synthesized, and tested by in vitro and ex vivo experiments, which revealed that several of them are capable to stimulate h TLR4 in vitro up to 25% activity of Monophosphoryl lipid A. The specific affinity of the in vitro most potent substance was confirmed by surface plasmon resonance direct-binding experiments. Moreover, two compounds from the series show also significant ability to elicit production of interleukin 6.

Toll immune signal activates cellular immune response via eicosanoids.

PubMed

Shafeeq, Tahir; Ahmed, Shabbir; Kim, Yonggyun

2018-07-01

Upon immune challenge, insects recognize nonself. The recognition signal will propagate to nearby immune effectors. It is well-known that Toll signal pathway induces antimicrobial peptide (AMP) gene expression. Eicosanoids play crucial roles in mediating the recognition signal to immune effectors by enhancing humoral immune response through activation of AMP synthesis as well as cellular immune responses, suggesting a functional cross-talk between Toll and eicosanoid signals. This study tested a cross-talk between these two signals. Two signal transducing factors (MyD88 and Pelle) of Toll immune pathway were identified in Spodoptera exigua. RNA interference (RNAi) of either SeMyD88 or SePelle expression interfered with the expression of AMP genes under Toll signal pathway. Bacterial challenge induced PLA 2 enzyme activity. However, RNAi of these two immune factors significantly suppressed the induction of PLA 2 enzyme activity. Furthermore, RNAi treatment prevented gene expression of cellular PLA 2 . Inhibition of PLA 2 activity reduced phenoloxidase activity and subsequent suppression in cellular immune response measured by hemocyte nodule formation. However, immunosuppression induced by RNAi of Toll signal molecules was significantly reversed by addition of arachidonic acid (AA), a catalytic product of PLA 2 . The addition also significantly reduced the enhanced fungal susceptibility of S. exigua treated by RNAi against two Toll signal molecules. These results indicate that there is a cross-talk between Toll and eicosanoid signals in insect immunity. Copyright © 2018 Elsevier Ltd. All rights reserved.

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.

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...

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.

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.

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.

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

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

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

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

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.

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

Complement Factor B is the Downstream Effector of Toll-Like Receptors and Plays an Important Role in a Mouse Model of Severe Sepsis¶

PubMed Central

Zou, Lin; Feng, Yan; Li, Yan; Zhang, Ming; Chen, Chan; Cai, Jiayan; Gong, Yu; Wang, Larry; Thurman, Joshua M.; Wu, Xiaobo; Atkinson, John P.; Chao, Wei

2013-01-01

Severe sepsis involves massive activation of the innate immune system and leads to high mortality. Previous studies have demonstrated that various types of Toll-like receptors (TLRs) mediate a systemic inflammatory response and contribute to organ injury and mortality in animal models of severe sepsis. However, the downstream mechanisms responsible for TLR-mediated septic injury are poorly understood. Here, we show that activation of TLR2, TLR3 and TLR4 markedly enhanced complement factor B (cfB) synthesis and release by macrophages and cardiac cells. Polymicrobial sepsis, created by cecal ligation and puncture (CLP) in a mouse model, augmented cfB levels in the serum, peritoneal cavity and major organs including the kidney and heart. CLP also led to the alternative pathway (AP) activation, C3 fragment deposition in the kidney and heart, and cfB-dependent C3dg elevation. Bacteria isolated from septic mice activated the serum AP via a factor D-dependent manner. MyD88 deletion attenuated cfB/C3 up-regulation as well as cleavage induced by polymicrobial infection. Importantly, during sepsis, absence of cfB conferred a protective effect with improved survival and cardiac function, and markedly attenuated acute kidney injury. cfB deletion also led to increased neutrophil migratory function during the early phase of sepsis, decreased local and systemic bacterial load, attenuated cytokine production and reduced neutrophil reactive oxygen species production. Together, our data indicate that cfB acts as a downstream effector of TLR signaling and plays a critical role in the pathogenesis of severe bacterial sepsis. PMID:24154627

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

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

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.

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.

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

Aeromonas salmonicida Infection Only Moderately Regulates Expression of Factors Contributing to Toll-Like Receptor Signaling but Massively Activates the Cellular and Humoral Branches of Innate Immunity in Rainbow Trout (Oncorhynchus mykiss)

PubMed Central

Brietzke, Andreas; Korytář, Tomáš; Jaros, Joanna; Köllner, Bernd; Goldammer, Tom; Seyfert, Hans-Martin; Rebl, Alexander

2015-01-01

Toll-like receptors (TLRs) are known to detect a defined spectrum of microbial structures. However, the knowledge about the specificity of teleost Tlr factors for distinct pathogens is limited so far. We measured baseline expression profiles of 18 tlr genes and associated signaling factors in four immune-relevant tissues of rainbow trout Oncorhynchus mykiss. Intraperitoneal injection of a lethal dose of Aeromonas salmonicida subsp. salmonicida induced highly increased levels of cytokine mRNAs during a 72-hour postinfection (hpi) period. In contrast, only the fish-specific tlr22a2 and the downstream factor irak1 featured clearly increased transcript levels, while the mRNA concentrations of many other tlr genes decreased. Flow cytometry quantified cell trafficking after infection indicating a dramatic influx of myeloid cells into the peritoneum and a belated low level immigration of lymphoid cells. T and B lymphocytes were differentiated with RT-qPCR revealing that B lymphocytes emigrated from and T lymphocytes immigrated into head kidney. In conclusion, no specific TLR can be singled out as a dominant receptor for A. salmonicida. The recruitment of cellular factors of innate immunity rather than induced expression of pathogen receptors is hence of key importance for mounting a first immune defense against invading A. salmonicida. PMID:26266270

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.

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

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

[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.

Gut-derived lipopolysaccharide promotes T-cell-mediated hepatitis in mice through Toll-like receptor 4.

PubMed

Lin, Yan; Yu, Le-Xing; Yan, He-Xin; Yang, Wen; Tang, Liang; Zhang, Hui-Lu; Liu, Qiong; Zou, Shan-Shan; He, Ya-Qin; Wang, Chao; Wu, Meng-Chao; Wang, Hong-Yang

2012-09-01

Robust clinical and epidemiologic data support the role of inflammation as a key player in hepatocellular carcinoma (HCC) development. Our previous data showed that gut-derived lipopolysaccharide (LPS) promote HCC development by activating Toll-like receptor 4 (TLR4) expressed on myeloid-derived cells. However, the effects of gut-derived LPS on other types of liver injury models are yet to be studied. The purpose of this study was to determine the importance of gut-derived LPS and TLR4 signaling in a T-cell-mediated hepatitis-Con A-induced hepatitis model, which mimic the viral hepatitis. Reduction of endotoxin using antibiotics regimen or genetic ablation of TLR4 in mice significantly alleviate Con A-induced liver injury by inhibiting the infiltration of T lymphocytes into the liver and the activation of CD4(+) T lymphocytes as well as the production of T helper 1 cytokines; in contrast, exogenous LPS can promote Con A-induced hepatitis and CD4(+) T cells activation in vivo and in vitro. Reconstitution of TLR4-expressing myeloid cells in TLR4-deficient mice restored Con A-induced liver injury and inflammation, indicating the major cell target of LPS. In addition, TLR4 may positively regulate the target hepatocellular apoptosis via the perforin/granzyme B pathway. These data suggest that gut-derived LPS and TLR4 play important positive roles in Con A-induced hepatitis and modulation of the gut microbiotia may represent a new avenue for therapeutic intervention to treat acute hepatitis induced by hepatitis virus infection, thus to prevent hepatocellular carcinoma.

Estrogen receptor alpha modulates toll-like receptor signaling in murine lupus

PubMed Central

Cunningham, Melissa A.; Naga, Osama S.; Eudaly, Jackie G.; Scott, Jennifer L.; Gilkeson, Gary S.

2013-01-01

Systemic lupus erythematosus (SLE) is a disease that disproportionately affects females. Despite significant research effort, the mechanisms underlying the female predominance in this disease are largely unknown. Previously, we showed that estrogen receptor alpha knockout (ERαKO) lupus prone female mice had significantly less pathologic renal disease and proteinuria, and significantly prolonged survival. Since autoantibody levels and number and percentage of B/T cells were not significantly impacted by ERα genotype, we hypothesized that the primary benefit of ERα deficiency in lupus nephritis was via modulation of the innate immune response. Using BMDCs and spleen cells/B cells from female wild-type or ERαKO mice, we found that ERαKO-derived cells have a significantly reduced inflammatory response after stimulation with TLR agonists. Our results indicate that the inflammatory response to TLR ligands is significantly impacted by the presence of ERα despite the absence of estradiol, and may partially explain the protective effect of ERα deficiency in lupus-prone animals. PMID:22659029

Altered behaviour and cognitive function following combined deletion of Toll-like receptors 2 and 4 in mice.

PubMed

Too, Lay Khoon; McGregor, Iain S; Baxter, Alan G; Hunt, Nicholas H

2016-04-15

Activation of the immune system due to infection or aging is increasingly linked to impaired neuropsychological function. Toll-like receptors 2 and 4 (TLR2, TLR4) are well-characterised for their role in inflammatory events, and their combined activation has been implicated in neurological diseases. We therefore determined whether TLR2 and TLR4 double gene knockout (GKO) mice showed modified behaviour and cognitive function during a 16-day test sequence that employed the automated IntelliCage test system. The IntelliCage features a home cage environment in which groups of mice live and where water reward is gained through performing various tasks centred on drinking stations in each corner of the apparatus. All mice were tested twice, one month apart (the first sequence termed "R1"and the second "R2"). There were fewer corner visits and nosepokes in TLR2/4 GKO compared to wild-type mice during early exploration in R1, suggesting elevated neophobia in GKO mice. Reduced exploration persisted over subsequent test modules during the dark phase. TLR2/4 GKO mice also displayed increased corner visits during drinking sessions compared to non-drinking sessions, but this was not associated with increased drinking. In subsequent, more complex test modules, TLR2/4 GKO mice had unimpaired spatial learning, but showed markedly poorer performance in a visual discrimination reversal task compared to wild-type mice. These results indicated subtle impairments in behaviour and cognitive functions due to double deficiency in TLR2 and TLR4. These finding are highly relevant to understanding the combined actions of TLR2 and TLR4 on neurological status in a range of different disease conditions. Crown Copyright © 2016. Published by Elsevier B.V. All rights reserved.

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.

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

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

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.

Toll-Booth Purification

NASA Technical Reports Server (NTRS)

1977-01-01

NASA's Technology Application Team at Stanford Research Institute searched available information and suggested a transfer of clean-room technology employing the use of the same laminar flow techniques found in environmental control systems of clean rooms used for contamination-free assembly of precision aerospace equipment. That information, from technology originally developed by NASA and the Energy Research & Development Administration was incorporated in the design of a prototype toll booth purifier. The draft-free design includes a "diffusor", which blows clean air out the toll booth doorway, thus retarding the infiltration of contaminated air. The net effect is a decrease in the toll collector's inhalation of exhaust fumes. The Washington Department of Highways installed the prototype system in a toll booth at the Evergreen Point Bridge near Seattle. After a successful two-year test, the department now has equipped all 10 of the bridge's toll booths with the air purifiers.

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

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

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

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

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

PubMed Central

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

2012-01-01

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. PMID:22675026

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.

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.

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

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.

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.

The toll-like receptor 2 agonist Pam3CSK4 is neuroprotective after spinal cord injury.

PubMed

Stivers, Nicole S; Pelisch, Nicolas; Orem, Ben C; Williams, Joshua; Nally, Jacqueline M; Stirling, David P

2017-08-01

Microglia/macrophage activation and recruitment following spinal cord injury (SCI) is associated with both detrimental and reparative functions. Stimulation of the innate immune receptor Toll-like receptor-2 (TLR2) has shown to be beneficial following SCI, and it increases axonal regeneration following optic nerve crush. However, the mechanism(s) remain unclear. As microglia express high levels of TLR2, we hypothesized that modulating the microglial response to injury using a specific TLR2 agonist, Pam3CSK4, would prevent secondary-mediated white matter degeneration following SCI. To test this hypothesis, we documented acute changes in microglia, axons, and oligodendroglia over time using two-photon excitation and an ex vivo laser-induced SCI (LiSCI) model. We utilized double transgenic mice that express GFP in either microglia or oligodendroglia, and YFP in axons, and we applied the lipophilic fluorescent dye (Nile Red) to visualize myelin. We found that treatment with Pam3CSK4 initiated one hour after injury induced a significant increase in the extent and timing of the microglial response to injury compared to vehicle controls. This enhanced response was observed 2 to 4h following SCI and was most prominent in areas closer to the ablation site. In addition, Pam3CSK4 treatment significantly reduced axonal dieback rostral and caudal to the ablation at 6h post-SCI. This protective effect of Pam3CSK4 was also mirrored when assessing secondary bystander axonal damage (i.e., axons spared by the primary injury that then succumb to secondary degeneration), and when assessing the survival of oligodendroglia. Following these imaging experiments, custom microarray analysis of the ex vivo spinal cord preparations revealed that Pam3CSK4-treatment induced an alternative (mixed M1:M2) microglial activation profile. In summary, our data suggest that by providing a second "sterile" activation signal to microglia through TLR2/TLR1 signaling, the microglial response to injury can

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

Spirulina lipopolysaccharides inhibit tumor growth in a Toll-like receptor 4-dependent manner by altering the cytokine milieu from interleukin-17/interleukin-23 to interferon-γ

PubMed Central

Okuyama, Hiromi; Tominaga, Akira; Fukuoka, Satoshi; Taguchi, Takahiro; Kusumoto, Yutaka; Ono, Shiro

2017-01-01

Th17 cells and the cytokine they produce, interleukin (IL)-17, play an important role in tumor progression in humans and in mice. IL-6 and IL-23 are critical cytokines for the differentiation and propagation of Th17 cells, respectively. Bacterial lipopolysaccharides (LPS) are known to stimulate immune cells to produce such inflammatory cytokines. Contrary to Escherichia coli (E. coli) LPS, LPS from Spirulina has low toxicity and barely induces in vivo production of IL-6 and IL-23 in mice. We examined the antitumor effects of Spirulina LPS compared to E. coli LPS in an MH134 hepatoma model. Administration of Spirulina LPS suppressed tumor growth in C3H/HeN mice, but not in Toll-like receptor 4 (TLR4)-mutant C3H/HeJ mice, by reducing serum levels of IL-17 and IL-23, while increasing interferon (IFN)-γ levels. The antitumor activity and IFN-γ production were mediated by T cells. Moreover, in vitro experiments showed that Spirulina LPS impaired the antigen-presenting function that supports the generation of IL-17-producing cells in a toll-like receptor (TLR)4-dependent manner. Of note, injection of anti-IL-17 antibody in tumor-bearing C3H/HeN mice in the absence of Spirulina LPS markedly suppressed tumor growth and augmented IFN-γ responses. Thus, our results support the notion that IFN-γ and IL-17/IL-23 mutually regulate Th17 and Th1 responses in tumor-bearing hosts, and Spirulina LPS modulates the balance of the IFN-γ-IL-17/IL-23 axis towards IFN-γ production, which leads to tumor inhibition. Furthermore, Spirulina LPS effectively inhibited the spontaneous development of mammary tumors. This study has important implications for the exploitation of TLR-based immunomodulators for cancer immunotherapy. PMID:28075473

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

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.

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.

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.

Mycobacterium tuberculosis Hip1 Dampens Macrophage Proinflammatory Responses by Limiting Toll-Like Receptor 2 Activation▿

PubMed Central

Madan-Lala, Ranjna; Peixoto, Katia Vitorello; Re, Fabio; Rengarajan, Jyothi

2011-01-01

Mycobacterium tuberculosis is a highly successful human pathogen that evades host innate immunity by interfering with macrophage functions. In addition to avoiding macrophage microbicidal activities, M. tuberculosis triggers secretion of proinflammatory cytokines and chemokines in macrophages. The levels of proinflammatory cytokines induced by clinical M. tuberculosis isolates are thought to play an important role in determining tuberculosis disease progression and severity, but the mechanisms by which M. tuberculosis modulates the magnitude of inflammatory responses remain unclear. Here we show that M. tuberculosis restricts robust macrophage activation and dampens proinflammatory responses through the cell envelope-associated serine hydrolase Hip1 (hydrolase important for pathogenesis 1). By transcriptionally profiling macrophages infected with either wild-type or hip1 mutant bacteria, we found that the hip1 mutant induced earlier and significantly higher levels of several proinflammatory cytokines and chemokines. We show that increased activation of Toll-like receptor 2 (TLR2)- and MyD88-dependent signaling pathways mediates the enhanced cytokine secretion induced by the hip1 mutant. Thus, Hip1 restricts the onset and magnitude of proinflammatory cytokines by limiting TLR2-dependent activation. We also show that Hip1 dampens TLR2-independent activation of the inflammasome and limits secretion of interleukin-18 (IL-18). Dampening of TLR2 signaling does not require viable M. tuberculosis or phagocytosis but does require Hip1 catalytic activity. We propose that M. tuberculosis restricts proinflammatory responses by masking cell surface interactions between TLR2 agonists on M. tuberculosis and TLR2 on macrophages. This strategy may allow M. tuberculosis to evade early detection by host immunity, delay the onset of adaptive immune responses, and accelerate disease progression. PMID:21947769

Mycobacterium tuberculosis Hip1 dampens macrophage proinflammatory responses by limiting toll-like receptor 2 activation.

PubMed

Madan-Lala, Ranjna; Peixoto, Katia Vitorello; Re, Fabio; Rengarajan, Jyothi

2011-12-01

Mycobacterium tuberculosis is a highly successful human pathogen that evades host innate immunity by interfering with macrophage functions. In addition to avoiding macrophage microbicidal activities, M. tuberculosis triggers secretion of proinflammatory cytokines and chemokines in macrophages. The levels of proinflammatory cytokines induced by clinical M. tuberculosis isolates are thought to play an important role in determining tuberculosis disease progression and severity, but the mechanisms by which M. tuberculosis modulates the magnitude of inflammatory responses remain unclear. Here we show that M. tuberculosis restricts robust macrophage activation and dampens proinflammatory responses through the cell envelope-associated serine hydrolase Hip1 (hydrolase important for pathogenesis 1). By transcriptionally profiling macrophages infected with either wild-type or hip1 mutant bacteria, we found that the hip1 mutant induced earlier and significantly higher levels of several proinflammatory cytokines and chemokines. We show that increased activation of Toll-like receptor 2 (TLR2)- and MyD88-dependent signaling pathways mediates the enhanced cytokine secretion induced by the hip1 mutant. Thus, Hip1 restricts the onset and magnitude of proinflammatory cytokines by limiting TLR2-dependent activation. We also show that Hip1 dampens TLR2-independent activation of the inflammasome and limits secretion of interleukin-18 (IL-18). Dampening of TLR2 signaling does not require viable M. tuberculosis or phagocytosis but does require Hip1 catalytic activity. We propose that M. tuberculosis restricts proinflammatory responses by masking cell surface interactions between TLR2 agonists on M. tuberculosis and TLR2 on macrophages. This strategy may allow M. tuberculosis to evade early detection by host immunity, delay the onset of adaptive immune responses, and accelerate disease progression.

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.

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.

Astragaloside IV attenuates injury caused by myocardial ischemia/reperfusion in rats via regulation of toll-like receptor 4/nuclear factor-κB signaling pathway.

PubMed

Lu, Meili; Tang, Futian; Zhang, Jing; Luan, Aina; Mei, Meng; Xu, Chonghua; Zhang, Suping; Wang, Hongxin; Maslov, Leonid N

2015-04-01

Myocardial ischemia/reperfusion (MI/R) injury, in which inflammatory response and cell apoptosis play a vital role, is frequently encountered in clinical practice. Astragaloside IV (AsIV), a small molecular saponin of Astragalus membranaceus, has been shown to confer protective effects against many cardiovascular diseases. The present study was aimed to investigate the antiinflammatory and antiapoptotic effects and the possible mechanism of AsIV on MI/R injury in rats. Rats were randomly divided into sham operation group, MI/R group and groups with combinations of MI/R and different doses of AsIV. The results showed that the expressions of myocardial toll-like receptor 4 (TLR4) and nuclear factor-κB (NF-κB) were significantly increased, and apoptosis of cardiomyocytes was induced in MI/R group compared with that in sham operation group. Administration of AsIV attenuated MI/R injury, downregulated the expressions of TLR4 and NF-κB and inhibited cell apoptosis as evidenced by decreased terminal deoxynucleotidyl transferase dUTP nick end labeling positive cells, B-cell lymphoma-2 associated X protein and caspase-3 expressions and increased B-cell lymphoma-2 expression compared with that in MI/R group. In addition, AsIV treatment reduced levels of inflammatory cytokines induced by MI/R injury. In conclusion, our results demonstrated that AsIV downregulates TLR4/NF-κB signaling pathway and inhibits cell apoptosis, subsequently attenuating MI/R injury in rats. Copyright © 2015 John Wiley & Sons, Ltd.

Toll-like receptor-2 agonist-allergen coupling efficiently redirects Th2 cell responses and inhibits allergic airway eosinophilia.

PubMed

Krishnaswamy, Jayendra Kumar; Jirmo, Adan Chari; Baru, Abdul Mannan; Ebensen, Thomas; Guzmán, Carlos A; Sparwasser, Tim; Behrens, Georg M N

2012-12-01

Toll-like receptor (TLR) agonists beneficially modulate allergic airway inflammation. However, the efficiency of TLR agonists varies considerably, and their exact cellular mechanisms (especially of TLR 2/6 agonists) are incompletely understood. We investigated at a cellular level whether the administration of the pharmacologically improved TLR2/6 agonist S-[2,3-bispalmitoyiloxy-(2R)-propyl]-R-cysteinyl-amido-monomethoxy polyethylene glycol (BPP) conjugated to antigenic peptide (BPP-OVA) could divert an existing Th2 response and influence airway eosinophilia. The effects of BPP-OVA on airway inflammation were assessed in a classic murine sensitization/challenge model and an adoptive transfer model, which involved the adoptive transfer of in vitro differentiated ovalbumin (OVA)-specific Th2 cells. Functional T-cell stimulation by lung dendritic cells (DCs) was determined both in vitro and in vivo, combined with a cytokine secretion analysis. A single mucosal application of BPP-OVA efficiently delivered antigen, led to TLR2-mediated DC activation, and resulted in OVA-specific T-cell proliferation via lung DCs in vivo. In alternative models of allergic airway disease, a single administration of BPP-OVA before OVA challenge (but not BPP alone) significantly reduced airway eosinophilia, most likely through altered antigen-specific T-cell stimulation via DCs. Analyses of adoptively transferred Th2-biased cells after BPP-OVA administration in vivo suggested that BPP-OVA guides antigen-specific Th2 cells to produce significantly higher amounts of IFN-γ upon allergen challenge. In conclusion, our data show for the first time that a single mucosal administration of a TLR 2/6 agonist-allergen conjugate can provoke IFN-γ responses in Th2-biased cells and alleviate allergic airway inflammation.

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.

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

Lactobacillus delbrueckii TUA4408L and its extracellular polysaccharides attenuate enterotoxigenic Escherichia coli-induced inflammatory response in porcine intestinal epitheliocytes via Toll-like receptor-2 and 4.

PubMed

Wachi, Satoshi; Kanmani, Paulraj; Tomosada, Yohsuke; Kobayashi, Hisakazu; Yuri, Toshihito; Egusa, Shintaro; Shimazu, Tomoyuki; Suda, Yoshihito; Aso, Hisashi; Sugawara, Makoto; Saito, Tadao; Mishima, Takashi; Villena, Julio; Kitazawa, Haruki

2014-10-01

Immunobiotics are known to modulate intestinal immune responses by regulating Toll-like receptor (TLR) signaling pathways, which are responsible for the induction of cytokines and chemokines in response to microbial-associated molecular patterns. However, little is known about the immunomodulatory activity of compounds or molecules from immunobiotics. We evaluated whether Lactobacillus delbrueckii subsp. delbrueckii TUA4408L (Ld) or its extracellular polysaccharide (EPS): acidic EPS (APS) and neutral EPS (NPS), modulated the response of porcine intestinal epitheliocyte (PIE) cells against Enterotoxigenic Escherichia coli (ETEC) 987P. The roles of TLR2, TLR4, and TLR negative regulators in the immunoregulatory effects were also studied. ETEC-induced inflammatory cytokines were downregulated when PIE cells were prestimulated with both Ld or EPSs. Ld, APS, and NPS inhibited ETEC mediated mitogen-activated protein kinase (MAPK) and nuclear factor-κB (NF-κB) activation by upregulating TLR negative regulators. The capability of Ld to suppress inflammatory cytokines was diminished when PIE cells were blocked with anti-TLR2 antibody, while APS failed to suppress inflammatory cytokines when cells were treated with anti-TLR4 antibody. Induction of Ca²⁺ fluxes in TLR knockdown cells confirmed that TLR2 plays a principal role in the immunomodulatory action of Ld, while the activity of APS is mediated by TLR4. In addition, NPS activity depends on both TLR4 and TLR2. Ld and its EPS have the potential to be used for the development of anti-inflammatory functional foods to prevent intestinal diseases in both humans and animals. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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.

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

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.

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

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

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.

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

Toll-like receptor (TLR)-4 mediates anti-β2GPI/β2GPI-induced tissue factor expression in THP-1 cells

PubMed Central

Zhou, H; Yan, Y; Xu, G; Zhou, B; Wen, H; Guo, D; Zhou, F; Wang, H

2011-01-01

Our previous study demonstrated that annexin A2 (ANX2) on cell surface could function as a mediator and stimulate tissue factor (TF) expression of monocytes by anti-β2-glycoprotein I/β2-glycoprotein I complex (anti-β2GPI/β2GPI). However, ANX2 is not a transmembrane protein and lacks the intracellular signal transduction pathway. Growing evidence suggests that Toll-like receptor 4 (TLR-4) might act as an ‘adaptor’ for intracellular signal transduction in anti-β2GPI/β2GPI-induced TF expressing cells. In the current study, we investigated the roles of TLR-4 and its related molecules, myeloid differentiation protein 2 (MD-2) and myeloid differentiation factor 88 (MyD88), in anti-β2GPI/β2GPI-induced TF expressing human monocytic-derived THP-1 (human acute monocytic leukaemia) cells. The relationship of TLR-4 and ANX2 in this process was also explored. Along with TF, expression of TLR-4, MD-2 and MyD88 in THP-1 cells increased significantly when treated by anti-β2GPI (10 µg/ml)/β2GPI (100 µg/ml) complex. The addition of paclitaxel, which competes with the MD-2 ligand, could inhibit the effects of anti-β2GPI/β2GPI on TLR-4, MD-2, MyD88 and TF expression. Both ANX2 and TLR-4 in THP-1 cell lysates could bind to β2GPI that had been conjugated to a column (β2GPI-Affi-Gel). Furthermore, TLR-4, MD-2, MyD88 and TF expression was remarkably diminished in THP-1 cells infected with ANX2-specific RNA interference (RNAi) lentivirus (LV-RNAi-ANX2), in spite of treatment with a similar concentration of anti-β2GPI/β2GPI complex. These results indicate that TLR-4 and its signal transduction pathway contribute to anti-β2GPI/β2GPI-induced TF expression in THP-1 cells, and the effects of TLR-4 with ANX2 are tightly co-operative. PMID:21091668

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.

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

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

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

Pelle kinase is activated by autophosphorylation during Toll signaling in Drosophila.

PubMed

Shen, Baohe; Manley, James L

2002-04-01

The Drosophila Pelle kinase plays a key role in the evolutionarily conserved Toll signaling pathway, but the mechanism responsible for its activation has been unknown. We present in vivo and in vitro evidence establishing an important role for concentration-dependent autophosphorylation in the signaling process. We first show that Pelle phosphorylation can be detected transiently in early embryos, concomitant with activation of signaling. Importantly, Pelle phosphorylation is enhanced in a gain-of-function Toll mutant (Toll(10b)), but decreased by loss-of-function Toll alleles. Next we found that Pelle is phosphorylated in transfected Schneider L2 cells in a concentration-dependent manner such that significant modification is observed only at high Pelle concentrations, which coincide with levels required for phosphorylation and activation of the downstream target, Dorsal. Pelle phosphorylation is also enhanced in L2 cells co-expressing Toll(10b), and is dependent on Pelle kinase activity. In vitro kinase assays revealed that recombinant, autophosphorylated Pelle is far more active than unphosphorylated Pelle. Importantly, unphosphorylated Pelle becomes autophosphorylated, and activated, by incubation at high concentrations. We discuss these results in the context of Toll-like receptor mediated signaling in both flies and mammals.

Toll-like receptor-4 is a target for suppression of proliferation and chemoresistance in HepG2 hepatoblastoma cells.

PubMed

Hsiao, Chih-Cheng; Chen, Po-Han; Cheng, Cheng-I; Tsai, Ming-Shian; Chang, Chih-Yang; Lu, Shang-Chieh; Hsieh, Ming-Chu; Lin, Yu-Chun; Lee, Po-Huang; Kao, Ying-Hsien

2015-11-01

Toll-like receptor-4 (TLR4) is known to influence growth and migration of hepatocellular tumors; however, its role in hepatoblastoma remains poorly understood. This study investigated the regulatory role of TLR4 in proliferation and chemoresistance of HepG2 hepatoblastoma cells. Treatment with lipopolysaccharide (LPS), a TLR4 agonist, was found to significantly upregulate TLR4 expression in HepG2 cells, but not in malignant Huh-7 and Sk-Hep1 hepatocellular carcinoma cells. Additionally, IL-6 enhanced LPS-induced TLR4 upregulation. LPS-stimulated TLR4 activation increased proliferation, nitric oxide synthase (NOS) expression, and NO production in HepG2 cells. Chemotherapeutic agents, cisplatin and doxorubicin, effectively inhibited TLR4 expression in HepG2 cells. Characterization of LPS-induced signaling activation and blockade with kinase inhibitors revealed the involvement of Akt and MAPK pathways in LPS-enhanced NO release from, and proliferation of HepG2 cells. Mechanistically, gene modifications as a result of TLR4 transfection and siRNA-mediated knockdown further demonstrated a crucial role for TLR4 in the regulation of NOS expression, cell proliferation, and chemoresistance in HepG2 cells. These findings suggest that targeting TLR4 expression and its cognate signaling may modulate proliferation and chemosensitivity in hepatoblastoma cells and serve as a potential therapeutic target. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Homeobox a5 Promotes White Adipose Tissue Browning Through Inhibition of the Tenascin C/Toll-Like Receptor 4/Nuclear Factor Kappa B Inflammatory Signaling in Mice.

PubMed

Cao, Weina; Huang, Hongtao; Xia, Tianyu; Liu, Chenlong; Muhammad, Saeed; Sun, Chao

2018-01-01

Lipopolysaccharide (LPS) induces rapid increase in systemic inflammatory factors. As adipose tissue is a key contributor to the inflammatory response to numerous metabolic stimuli, it is important to understand the mechanism behind the LPS-induced inflammation in white adipose tissue (WAT). Homeobox a5 (Hoxa5) is an important transcription factor, which is highly expressed in adipose tissue, and its mRNA expression is increased at cold exposure in mice. So far, the function of Hoxa5 in adipose tissue browning has been poorly understood. So, the objective of this study was conducted to determine the role of Hoxa5 in adipose inflammatory response and white adipose browning in mice. LPS-induced inflammatory and cold-induced browning model were conducted. We compared the coordinated role of Hoxa5 in inflammation and thermogenesis of mice adipose. Transcriptional and methylation regulation was determined by luciferase assay, electrophoretic mobility shift assay, and bisulfite conversion experiment. Hoxa5 and tenascin C (TNC) were involved in WAT inflammation and browning in mice with LPS injection. Furthermore, Hoxa5 inhibited the TNC-involved activation of Toll-like receptor (TLR) 4/nuclear factor kappa B (NF-κB) signal pathway and promoted WAT browning. Moreover, we found that a BMP4/Smad1 signal, closely related to browning, was activated by Hoxa5. Hoxa5 relieved adipocyte inflammation by decreasing TNC-mediated TLR4 transducer and activator of the NF-κB pathway. Interestingly, descended methylation level increased Hoxa5 expression in cold exposure. Our findings demonstrated that Hoxa5 alleviated inflammation and enhanced browning of adipose tissue via negative control of TNC/TLR4/NF-κB inflammatory signaling and activating BMP4/Smad1 pathway. These findings indicated a novel potential means for the regulation of inflammation in adipocytes to prevent obesity and other inflammatory diseases.

Modulating toll-like receptor-mediated inflammatory responses following exposure of whole cell and lipopolysaccharide component from Porphyromonas gingivalis in wistar rat models

PubMed Central

Nelwan, Sindy Cornelia; Nugraha, Ricardo Adrian; Endaryanto, Anang; Retno, Indrawati

2017-01-01

Objective: To explore host innate inflammatory response and the signal pathway induced by Porphyromonas gingivalis by measuring level of toll-like receptor 2 (TLR2) and TLR4 activity. Materials and Methods: Animal experimental study with pretest-posttest controlled group design were done between January 1 and December 10, 2016.. Total of 28 wistar rats had been used, randomized into 7 groups, each were given various dose of intra-sulcural injection of Porphyromonas gingivalis lipopolysaccharide. Statistical Analysis: Normality were measured by Shapiro–Wilk test, while statistical analysis made by ANOVA, t test, Pearson, and linear regression model.. Results: At day 0, no significant difference TLR2 and TLR4 level were measured. At day 4, there is a slight difference between TLR2 and TLR4 level in each group. At day 11, there is a significant difference between TLR2 and TLR4 level in each group. Group with exposure of whole cell will develop greater TLR2 but lower TLR4 level. In the contrary, group with exposure of LPS will develop greater TLR4 but lower TLR2 level. Conclusion: Our data supported that P. gingivalis played a vital role in the pathogenesis of pathogen-induced inflammatory responses in which TLR2 and TLR4 have different molecular mechanisms following recognition of pathogens and inflammatory response. PMID:29279665

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.

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.

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.

Toll-Like Receptor and Accessory Molecule mRNA Expression in Humans and Mice as Well as in Murine Autoimmunity, Transient Inflammation, and Progressive Fibrosis

PubMed Central

Ramaiah, Santhosh Kumar Vankayala; Günthner, Roman; Lech, Maciej; Anders, Hans-Joachim

2013-01-01

The cell type-, organ-, and species-specific expression of the Toll-like receptors (TLRs) are well described, but little is known about the respective expression profiles of their accessory molecules. We therefore determined the mRNA expression levels of LBP, MD2, CD36, CD14, granulin, HMGB1, LL37, GRP94, UNC93b1, TRIL, PRAT4A, AP3B1, AEP and the respective TLRs in human and mouse solid organs. Humans and mice displayed significant differences between their respective mRNA expression patterns of these factors. In addition, the expression profiles in transient tissue inflammation upon renal ischemia-reperfusion injury, in spleens and kidneys from mice with lupus-like systemic autoimmunity, and in progressive tissue fibrosis upon unilateral ureteral obstruction were studied. Several TLR co-factors were specifically regulated during the different phases of these disease entities, suggesting a functional involvement in the disease process. Thus, the organ- and species-specific expression patterns need to be considered in the design and interpretation of studies related to TLR-mediated innate immunity, which seems to be involved in the tissue injury phase, in the phase of tissue regeneration, and in progressive tissue remodelling. PMID:23803655

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.

4-Methoxylonchocarpin attenuates inflammation by inhibiting lipopolysaccharide binding to Toll-like receptor of macrophages and M1 macrophage polarization.

PubMed

Jang, Hyo-Min; Kang, Geum-Dan; Van Le, Thi Kim; Lim, Su-Min; Jang, Dae-Sik; Kim, Dong-Hyun

2017-04-01

The roots of Abrus precatorius (AP, Fabaceae) have traditionally been used in Vietnam and China for the treatment of inflammatory diseases such as stomatitis, asthma, bronchitis, and hepatitis. Therefore, in this study, we isolated 4-methoxylonchocarpin (ML), an anti-inflammatory compound present in AP, and studied its anti-inflammatory effects in mice with 2,4,6-trinitrobenzenesulfonic acid (TNBS)-induced colitis. In lipopolysaccharide (LPS)-stimulated macrophages, ML was found to inhibit nuclear factor (NF)-κB activation and tumor necrosis factor (TNF) and interleukin (IL)-6 expression by inhibiting LPS binding to Toll-like receptor 4 (TLR4) in vitro. Oral administration of ML in mice with TNBS-induced colitis suppressed colon shortening and colonic myeloperoxidase activity. ML treatment significantly inhibited the activation of nuclear factor (NF)-κB and phosphorylation of transforming growth factor β-activated kinase 1 in the colon. Treatment with ML also inhibited TNBS-induced expression of IL-1β, IL-17A, and TNF. While ML reduced the TNBS-induced expression of M1 macrophage markers such as arginase-2 and TNF, it was found to increase the expression of M2 macrophage markers such as arginase-1 and IL-10. In conclusion, oral administration of ML attenuated colitis in mice by inhibiting the binding of LPS to TLR4 on immune cells and increasing the polarization of M1 macrophages to M2 macrophages. Copyright © 2017 Elsevier B.V. All rights reserved.

Toll-like receptors 2 and 4 contribute to sepsis-induced depletion of spleen dendritic cells.

PubMed

Pène, Frédéric; Courtine, Emilie; Ouaaz, Fatah; Zuber, Benjamin; Sauneuf, Bertrand; Sirgo, Gonzalo; Rousseau, Christophe; Toubiana, Julie; Balloy, Viviane; Chignard, Michel; Mira, Jean-Paul; Chiche, Jean-Daniel

2009-12-01

Depletion of dendritic cells (DC) in secondary lymphoid organs is a hallmark of sepsis-induced immune dysfunction. In this setting, we investigated if Toll-like receptor (TLR)-dependent signaling might modulate the maturation process and the survival of DC. Using a model of sublethal polymicrobial sepsis induced by cecal ligation and puncture, we investigated the quantitative and functional features of spleen DC in wild-type, TLR2(-/-), TLR4(-/-), and TLR2(-/-) TLR4(-/-) mice. By 24 h, a decrease in the relative percentage of CD11c(high) spleen DC occurred in wild-type mice but was prevented in TLR2(-/-), TLR4(-/-), and TLR2(-/-) TLR4(-/-) mice. In wild-type mice, sepsis dramatically affected both CD11c(+) CD8alpha(+) and CD11c(+) CD8alpha(-) subsets. In all three types of knockout mice studied, the CD11c(+) CD8alpha(+) subset followed a depletion pattern similar to that for wild-type mice. In contrast, the loss of CD11c(+) CD8alpha(-) cells was attenuated in TLR2(-/-) and TLR4(-/-) mice and completely prevented in TLR2(-/-) TLR4(-/-) mice. Accordingly, apoptosis of spleen DC was increased in septic wild-type mice and inhibited in knockout mice. In addition we characterized the functional features of spleen DC obtained from septic mice. As shown by increased expression of major histocompatibility complex class II and CD86, polymicrobial sepsis induced maturation of DC, with subsequent increased capacity to prime T lymphocytes, similarly in wild-type and knockout mice. In response to CpG DNA stimulation, production of interleukin-12 was equally impaired in DC obtained from wild-type and knockout septic mice. In conclusion, although dispensable for the DC maturation process, TLR2 and TLR4 are involved in the mechanisms leading to depletion of spleen DC following polymicrobial sepsis.

Insulin-like growth factor-I gene delivery to astrocytes reduces their inflammatory response to lipopolysaccharide

PubMed Central

2011-01-01

Background Insulin-like growth factor-I (IGF-I) exerts neuroprotective actions in the central nervous system that are mediated at least in part by control of activation of astrocytes. In this study we have assessed the efficacy of exogenous IGF-I and IGF-I gene therapy in reducing the inflammatory response of astrocytes from cerebral cortex. Methods An adenoviral vector harboring the rat IGF-I gene and a control adenoviral vector harboring a hybrid gene encoding the herpes simplex virus type 1 thymidine kinase fused to Aequorea victoria enhanced green fluorescent protein were used in this study. Primary astrocytes from mice cerebral cortex were incubated for 24 h or 72 h with vehicle, IGF-I, the IGF-I adenoviral vector, or control vector; and exposed to bacterial lipopolysaccharide to induce an inflammatory response. IGF-I levels were measured by radioimmunoassay. Levels of interleukin 6, tumor necrosis factor-α, interleukin-1β and toll-like receptor 4 mRNA were assessed by quantitative real-time polymerase chain reaction. Levels of IGF-I receptor and IGF binding proteins 2 and 3 were assessed by western blotting. The subcellular distribution of nuclear factor κB (p65) was assessed by immunocytochemistry. Statistical significance was assessed by one way analysis of variance followed by the Bonferroni pot hoc test. Results IGF-I gene therapy increased IGF-I levels without affecting IGF-I receptors or IGF binding proteins. Exogenous IGF-I, and IGF-I gene therapy, decreased expression of toll-like receptor 4 and counteracted the lipopolysaccharide-induced inflammatory response of astrocytes. In addition, IGF-I gene therapy decreased lipopolysaccharide-induced translocation of nuclear factor κB (p65) to the cell nucleus. Conclusion These findings demonstrate efficacy of exogenous IGF-I and of IGF-I gene therapy in reducing the inflammatory response of astrocytes. IGF-I gene therapy may represent a new approach to reduce inflammatory reactions in glial cells. PMID

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

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.

Local Delivery of the Toll-Like Receptor 9 Ligand CpG Downregulates Host Immune and Inflammatory Responses, Ameliorating Established Leishmania (Viannia) panamensis Chronic Infection

PubMed Central

Fernández, Olga L.; Rodriguez-Pinto, Daniel; Castilho, Tiago M.; Corral Caridad, Maria J.; Goldsmith-Pestana, Karen; Saravia, Nancy Gore; McMahon-Pratt, Diane

2017-01-01

ABSTRACT Infection by Leishmania (Viannia) panamensis, the predominant etiologic agent for cutaneous leishmaniasis in Colombia, is characterized by a chronic mixed inflammatory response. Current treatment options are plagued by toxicity, lengthy treatment regimens, and growing evidence of drug resistance. Immunotherapy, modulating the immune system to mount a protective response, may provide an alternate therapeutic approach. We investigated the ability of the Toll-like receptor 9 (TLR9) ligand CpG to modulate established disease in the L. (V.) panamensis mouse model. Treatment of established infection with a high dose (50 μg) of CpG ameliorated disease and lowered parasite burden. Interestingly, immediately after treatment there was a significant increase in transforming growth factor β (TGF-β) and concomitantly an increase in T regulatory cell (Treg) function. Although a general reduction in cell-mediated immune cytokine and chemokine (gamma interferon [IFN-γ], interleukin 10 [IL-10], IL-13, IL-6, granulocyte-macrophage colony-stimulating factor [GM-CSF], IL-4, and MIP-1α) responses of the treated mice was observed, certain chemokines (RANTES, monocyte chemoattractant protein 1[MCP-1], and IP-10) were increased. Further, in peripheral blood mononuclear cells (PBMCs) from patients with cutaneous leishmaniasis, CpG treatment similarly exhibited a dose-response effect on the production of IFN-γ, IL-17, IL-10, and IL-13, with reductions observed at higher doses. To further understand the underlying mechanisms and cell populations driving the CpG mediated response, we examined the ex vivo dose effects mediated by the TLR9+ cell populations (dendritic cells, macrophages, and B cells) found to accumulate labeled CpG in vivo. Notably, B cells altered the production of IL-17, IL-13, and IFN-γ, supporting a role for B cells functioning as antigen-presenting cells (APCs) and/or regulatory cells during infection. Interestingly, B cells have been previously

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.

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.

Higher expression of galectin-3 and galectin-9 in periapical granulomas than in radicular cysts and an increased toll-like receptor-2 and toll-like receptor-4 expression are associated with reactivation of periapical inflammation.

PubMed

de Oliveira, Rita de Cássia Medeiros; Beghini, Marcela; Borges, Cláudia Renata Bibiano; Alves, Polyanna Miranda; de Araújo, Marcelo Sivieri; Pereira, Sanívia Aparecida de Lima; Rodrigues, Virmondes; Rodrigues, Denise Bertulucci Rocha

2014-02-01

Cysts and periapical granulomas are inflammatory reactions that develop in response to periapical infection by microbial species in dental root canal. It is known that toll-like receptors (TLRs) are pathogen recognition molecules and that galectins are lectins that can be associated with the inflammatory process, stimulating or inhibiting the immune system. The objective of this study was to evaluate the in situ expression of TLRs and galectins in radicular cysts and periapical granulomas. We analyzed 62 cases (30 radicular cysts, 27 periapical granulomas, and 5 control cases). Indirect immunohistochemistry was used to evaluate the expression of TLRs (TRL-2 and TLR-4) and galectins (Gal-3 and Gal-9). The expression of Gal-3 and Gal-9 was significantly higher in periapical granulomas and radicular cysts than in the control group. Similarly, both Gal-3 and Gal-9 were expressed significantly more in periapical granulomas than in radicular cysts. The expression of TLR-2 was significantly higher in periapical granulomas and radicular cysts than in the control group, and it was also significantly higher in radicular cysts with sinus tract than in the cases without sinus tract. Furthermore, the expression of TLR-4 was significantly higher in the cases of periapical granulomas with sinus tract than in the cases without sinus tract. Gal-3/Gal-9 and TLR-2/TLR-4 expression in the periapical granulomas and radicular cysts is associated with reactive periapical inflammation. Pathobiology of periapical disease is a very complex interplay of many bioactive molecules involved in immunoinflammatory responses. Up-regulation of these bioactive molecules might be an important modulator of inflammatory periapical lesions. Copyright © 2014 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

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.

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.

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.

[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.

Knockout of toll-like receptor-2 attenuates both the proinflammatory state of diabetes and incipient diabetic nephropathy.

PubMed

Devaraj, Sridevi; Tobias, Peter; Kasinath, Balakuntalam S; Ramsamooj, Rajendra; Afify, Alaa; Jialal, Ishwarlal

2011-08-01

Type 1 diabetes (T1DM) is a proinflammatory state and confers an increased risk for vascular complications. Toll-like receptors (TLR) could participate in diabetic vasculopathies. Whether TLR activation contributes to the proinflammatory state of T1DM and the pathogenesis of diabetic nephropathy remains unknown. We induced T1DM in TLR2 knockout mice (TLR2-/-) and wild-type littermates (C57BL/6J-WT) using streptozotocin (STZ). Fasting blood, peritoneal macrophages, and kidneys were obtained for flow cytometry, Western blot, microscopy, and cytokine assays at 6 and 14 weeks after induction of diabetes. Macrophage TLR2 expression and MyD88-dependent signaling were increased in diabetic mice (WT+STZ) compared with nondiabetic WT mice. These biomarkers were attenuated in diabetic TLR2-/- macrophages. WT+STZ mice showed increased kidney:body weight ratio due to cell hypertrophy, increased albuminuria, decreased kidney nephrin, podocin, and podocyte number and increased transforming growth factor-β and laminin compared with WT mice. Nephrin, podocin, and podocyte number and effacement were restored, and transforming growth factor-β and laminin levels were decreased in TLR2-/-+ STZ mice kidneys versus WT+STZ. Peritoneal and kidney macrophages were predominantly M1 phenotype in WT+STZ mice; this was attenuated in TLR2-/-+STZ mice. These data support a role for TLR2 in promoting inflammation and early changes of incipient diabetic nephropathy, in addition to albuminuria and podocyte loss.

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.

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.

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

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.

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

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.

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

Structure–activity correlations of variant forms of the B pentamer of Escherichia coli type II heat-labile enterotoxin LT-IIb with Toll-like receptor 2 binding

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

Cody, Vivian, E-mail: cody@hwi.buffalo.edu; University at Buffalo, 700 Ellicott Street, Buffalo, NY 14203; Pace, Jim

2012-12-01

Structural data for the S74D variant of the pentameric B subunit of type II heat-labile enterotoxin of Escherichia coli reveal a smaller pore opening that may explain its reduced Toll-like receptor binding affinity compared to that of the wild type enterotoxin. The explanation for the enhanced Toll-like receptor binding affinity of the S74A variant is more complex than simply being attributed to the pore opening. The pentameric B subunit of the type II heat-labile enterotoxin of Escherichia coli (LT-IIb-B{sub 5}) is a potent signaling molecule capable of modulating innate immune responses. It has previously been shown that LT-IIb-B{sub 5}, butmore » not the LT-IIb-B{sub 5} Ser74Asp variant [LT-IIb-B{sub 5}(S74D)], activates Toll-like receptor (TLR2) signaling in macrophages. Consistent with this, the LT-IIb-B{sub 5}(S74D) variant failed to bind TLR2, in contrast to LT-IIb-B{sub 5} and the LT-IIb-B{sub 5} Thr13Ile [LT-IIb-B{sub 5}(T13I)] and LT-IIb-B{sub 5} Ser74Ala [LT-IIb-B{sub 5}(S74A)] variants, which displayed the highest binding activity to TLR2. Crystal structures of the Ser74Asp, Ser74Ala and Thr13Ile variants of LT-IIb-B{sub 5} have been determined to 1.90, 1.40 and 1.90 Å resolution, respectively. The structural data for the Ser74Asp variant reveal that the carboxylate side chain points into the pore, thereby reducing the pore size compared with that of the wild-type or the Ser74Ala variant B pentamer. On the basis of these crystallographic data, the reduced TLR2-binding affinity of the LT-IIb-B{sub 5}(S74D) variant may be the result of the pore of the pentamer being closed. On the other hand, the explanation for the enhanced TLR2-binding activity of the LT-IIb-B{sub 5}(S74A) variant is more complex as its activity is greater than that of the wild-type B pentamer, which also has an open pore as the Ser74 side chain points away from the pore opening. Data for the LT-IIb-B{sub 5}(T13I) variant show that four of the five variant side chains point to the

Prevention and Mitigation of Acute Radiation Syndrome in Mice by Synthetic Lipopeptide Agonists of Toll-Like Receptor 2 (TLR2)

PubMed Central

Shakhov, Alexander N.; Singh, Vijay K.; Bone, Frederick; Cheney, Alec; Kononov, Yevgeniy; Krasnov, Peter; Bratanova-Toshkova, Troitza K.; Shakhova, Vera V.; Young, Jason; Weil, Michael M.; Panoskaltsis-Mortari, Angela; Orschell, Christie M.; Baker, Patricia S.; Gudkov, Andrei; Feinstein, Elena

2012-01-01

Bacterial lipoproteins (BLP) induce innate immune responses in mammals by activating heterodimeric receptor complexes containing Toll-like receptor 2 (TLR2). TLR2 signaling results in nuclear factor-kappaB (NF-κB)-dependent upregulation of anti-apoptotic factors, anti-oxidants and cytokines, all of which have been implicated in radiation protection. Here we demonstrate that synthetic lipopeptides (sLP) that mimic the structure of naturally occurring mycoplasmal BLP significantly increase mouse survival following lethal total body irradiation (TBI) when administered between 48 hours before and 24 hours after irradiation. The TBI dose ranges against which sLP are effective indicate that sLP primarily impact the hematopoietic (HP) component of acute radiation syndrome. Indeed, sLP treatment accelerated recovery of bone marrow (BM) and spleen cellularity and ameliorated thrombocytopenia of irradiated mice. sLP did not improve survival of irradiated TLR2-knockout mice, confirming that sLP-mediated radioprotection requires TLR2. However, sLP was radioprotective in chimeric mice containing TLR2-null BM on a wild type background, indicating that radioprotection of the HP system by sLP is, at least in part, indirect and initiated in non-BM cells. sLP injection resulted in strong transient induction of multiple cytokines with known roles in hematopoiesis, including granulocyte colony-stimulating factor (G-CSF), keratinocyte chemoattractant (KC) and interleukin-6 (IL-6). sLP-induced cytokines, particularly G-CSF, are likely mediators of the radioprotective/mitigative activity of sLP. This study illustrates the strong potential of LP-based TLR2 agonists for anti-radiation prophylaxis and therapy in defense and medical scenarios. PMID:22479357

Prevention and mitigation of acute radiation syndrome in mice by synthetic lipopeptide agonists of Toll-like receptor 2 (TLR2).

PubMed

Shakhov, Alexander N; Singh, Vijay K; Bone, Frederick; Cheney, Alec; Kononov, Yevgeniy; Krasnov, Peter; Bratanova-Toshkova, Troitza K; Shakhova, Vera V; Young, Jason; Weil, Michael M; Panoskaltsis-Mortari, Angela; Orschell, Christie M; Baker, Patricia S; Gudkov, Andrei; Feinstein, Elena

2012-01-01

Bacterial lipoproteins (BLP) induce innate immune responses in mammals by activating heterodimeric receptor complexes containing Toll-like receptor 2 (TLR2). TLR2 signaling results in nuclear factor-kappaB (NF-κB)-dependent upregulation of anti-apoptotic factors, anti-oxidants and cytokines, all of which have been implicated in radiation protection. Here we demonstrate that synthetic lipopeptides (sLP) that mimic the structure of naturally occurring mycoplasmal BLP significantly increase mouse survival following lethal total body irradiation (TBI) when administered between 48 hours before and 24 hours after irradiation. The TBI dose ranges against which sLP are effective indicate that sLP primarily impact the hematopoietic (HP) component of acute radiation syndrome. Indeed, sLP treatment accelerated recovery of bone marrow (BM) and spleen cellularity and ameliorated thrombocytopenia of irradiated mice. sLP did not improve survival of irradiated TLR2-knockout mice, confirming that sLP-mediated radioprotection requires TLR2. However, sLP was radioprotective in chimeric mice containing TLR2-null BM on a wild type background, indicating that radioprotection of the HP system by sLP is, at least in part, indirect and initiated in non-BM cells. sLP injection resulted in strong transient induction of multiple cytokines with known roles in hematopoiesis, including granulocyte colony-stimulating factor (G-CSF), keratinocyte chemoattractant (KC) and interleukin-6 (IL-6). sLP-induced cytokines, particularly G-CSF, are likely mediators of the radioprotective/mitigative activity of sLP. This study illustrates the strong potential of LP-based TLR2 agonists for anti-radiation prophylaxis and therapy in defense and medical scenarios.

Trichinella spiralis Excretory–Secretory Products Induce Tolerogenic Properties in Human Dendritic Cells via Toll-Like Receptors 2 and 4

PubMed Central

Ilic, Nataša; Gruden-Movsesijan, Alisa; Cvetkovic, Jelena; Tomic, Sergej; Vucevic, Dragana Bozidar; Aranzamendi, Carmen; Colic, Miodrag; Pinelli, Elena; Sofronic-Milosavljevic, Ljiljana

2018-01-01

Trichinella spiralis, as well as its muscle larvae excretory–secretory products (ES L1), given either alone or via dendritic cells (DCs), induce a tolerogenic immune microenvironment in inbred rodents and successfully ameliorate experimental autoimmune encephalomyelitis. ES L1 directs the immunological balance away from T helper (Th)1, toward Th2 and regulatory responses by modulating DCs phenotype. The ultimate goal of our work is to find out if it is possible to translate knowledge obtained in animal model to humans and to generate human tolerogenic DCs suitable for therapy of autoimmune diseases through stimulation with ES L1. Here, the impact of ES L1 on the activation of human monocyte-derived DCs is explored for the first time. Under the influence of ES L1, DCs acquired tolerogenic (semi-matured) phenotype, characterized by low expression of HLA-DR, CD83, and CD86 as well as moderate expression of CD40, along with the unchanged production of interleukin (IL)-12 and elevated production of IL-10 and transforming growth factor (TGF)-β, compared to controls. The interaction with DCs involved toll-like receptors (TLR) 2 and 4, and this interaction was mainly responsible for the phenotypic and functional properties of ES L1-treated DCs. Importantly, ES L1 potentiated Th2 polarizing capacity of DCs, and impaired their allo-stimulatory and Th1/Th17 polarizing properties. Moreover, ES L1-treated DCs promoted the expansion of IL-10- and TGF-β- producing CD4+CD25hiFoxp3hi T cells in indolamine 2, 3 dioxygenase (IDO)-1-dependent manner and increased the suppressive potential of the primed T cell population. ES L1-treated DCs retained the tolerogenic properties, even after the challenge with different pro-inflammatory stimuli, including those acting via TLR3 and, especially TLR4. These results suggest that the induction of tolerogenic properties of DCs through stimulation with ES L1 could represent an innovative approach for the preparation of tolerogenic DC for

Cervical cancer cell supernatants induce a phenotypic switch from U937-derived macrophage-activated M1 state into M2-like suppressor phenotype with change in Toll-like receptor profile.

PubMed

Sánchez-Reyes, Karina; Bravo-Cuellar, Alejandro; Hernández-Flores, Georgina; Lerma-Díaz, José Manuel; Jave-Suárez, Luis Felipe; Gómez-Lomelí, Paulina; de Celis, Ruth; Aguilar-Lemarroy, Adriana; Domínguez-Rodríguez, Jorge Ramiro; Ortiz-Lazareno, Pablo Cesar

2014-01-01

Cervical cancer (CC) is the second most common cancer among women worldwide. Infection with human papillomavirus (HPV) is the main risk factor for developing CC. Macrophages are important immune effector cells; they can be differentiated into two phenotypes, identified as M1 (classically activated) and M2 (alternatively activated). Macrophage polarization exerts profound effects on the Toll-like receptor (TLR) profile. In this study, we evaluated whether the supernatant of human CC cells HeLa, SiHa, and C-33A induces a shift of M1 macrophage toward M2 macrophage in U937-derived macrophages. The results showed that soluble factors secreted by CC cells induce a change in the immunophenotype of macrophages from macrophage M1 into macrophage M2. U937-derived macrophages M1 released proinflammatory cytokines and nitric oxide; however, when these cells were treated with the supernatant of CC cell lines, we observed a turnover of M1 toward M2. These cells increased CD163 and IL-10 expression. The expression of TLR-3, -7, and -9 is increased when the macrophages were treated with the supernatant of CC cells. Our result strongly suggests that CC cells may, through the secretion of soluble factors, induce a change of immunophenotype M1 into M2 macrophages.

Combined Prediction Model of Death Toll for Road Traffic Accidents Based on Independent and Dependent Variables

PubMed Central

Zhong-xiang, Feng; Shi-sheng, Lu; Wei-hua, Zhang; Nan-nan, Zhang

2014-01-01

In order to build a combined model which can meet the variation rule of death toll data for road traffic accidents and can reflect the influence of multiple factors on traffic accidents and improve prediction accuracy for accidents, the Verhulst model was built based on the number of death tolls for road traffic accidents in China from 2002 to 2011; and car ownership, population, GDP, highway freight volume, highway passenger transportation volume, and highway mileage were chosen as the factors to build the death toll multivariate linear regression model. Then the two models were combined to be a combined prediction model which has weight coefficient. Shapley value method was applied to calculate the weight coefficient by assessing contributions. Finally, the combined model was used to recalculate the number of death tolls from 2002 to 2011, and the combined model was compared with the Verhulst and multivariate linear regression models. The results showed that the new model could not only characterize the death toll data characteristics but also quantify the degree of influence to the death toll by each influencing factor and had high accuracy as well as strong practicability. PMID:25610454

Combined prediction model of death toll for road traffic accidents based on independent and dependent variables.

PubMed

Feng, Zhong-xiang; Lu, Shi-sheng; Zhang, Wei-hua; Zhang, Nan-nan

2014-01-01

In order to build a combined model which can meet the variation rule of death toll data for road traffic accidents and can reflect the influence of multiple factors on traffic accidents and improve prediction accuracy for accidents, the Verhulst model was built based on the number of death tolls for road traffic accidents in China from 2002 to 2011; and car ownership, population, GDP, highway freight volume, highway passenger transportation volume, and highway mileage were chosen as the factors to build the death toll multivariate linear regression model. Then the two models were combined to be a combined prediction model which has weight coefficient. Shapley value method was applied to calculate the weight coefficient by assessing contributions. Finally, the combined model was used to recalculate the number of death tolls from 2002 to 2011, and the combined model was compared with the Verhulst and multivariate linear regression models. The results showed that the new model could not only characterize the death toll data characteristics but also quantify the degree of influence to the death toll by each influencing factor and had high accuracy as well as strong practicability.

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

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

Leptospira santorosai Serovar Shermani detergent extract induces an increase in fibronectin production through a Toll-like receptor 2-mediated pathway.

PubMed

Tian, Ya-Chung; Hung, Cheng-Chieh; Li, Yi-Jung; Chen, Yung-Chang; Chang, Ming-Yang; Yen, Tzung-Hai; Hsu, Hsiang-Hao; Wu, Mai-Szu; Phillips, Aled; Yang, Chih-Wei

2011-03-01

Leptospirosis can activate inflammatory responses through Toll-like receptors (TLRs) and may cause renal tubulointerstitial fibrosis characterized by the accumulation of extracellular matrix (ECM). We have previously demonstrated that Leptospira santorosai serovar Shermani detergent extract stimulates ECM accumulation in vitro. The aim of this study was to examine the mechanistic basis of these previous observations and, in particular, to examine the potential involvement of TLRs. The addition of serovar Shermani detergent extract led to an increase in fibronectin gene expression and production. Inhibition of TLR2 but not TLR4 expression abrogated serovar Shermani detergent extract-mediated increases in fibronectin production. This response was also blocked by the knockdown of the gene expression of the TLR2 downstream transducers myeloid differentiation factor 88 (MyD88) and tumor necrosis factor receptor-associated factor 6 (TRAF6). Serovar Shermani detergent extract also activated nuclear factor-κB, and its inhibition by curcumin-attenuated serovar Shermani detergent extract induced increases in fibronectin production. These effects were also mimicked by the specific TLR2 agonist, Pam(3)CsK(4), a response that was also abrogated by the knockdown of MyD88 and TRAF6. Similarly, the administration of live leptospires to cells also induced fibronectin production that was blocked by inhibition of TLR2 and MyD88 expression. In conclusion, serovar Shermani detergent extract can induce fibronectin production through the TLR2-associated cascade, providing evidence of an association between TLRs and leptospirosis-mediated ECM deposition.

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

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.

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.

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.

CCR8 signaling influences Toll-like receptor 4 responses in human macrophages in inflammatory diseases.

PubMed

Reimer, Martina Kvist; Brange, Charlotte; Rosendahl, Alexander

2011-12-01

CCR8 immunity is generally associated with Th2 responses in allergic diseases. In this study, we demonstrate for the first time a pronounced attenuated influx of macrophages in ovalbumin (OVA)-challenged CCR8 knockout mice. To explore whether macrophages in human inflamed lung tissue also were CCR8 positive, human lung tissue from patients with chronic obstructive pulmonary disease (COPD) was evaluated. Indeed, CCR8 expression was pronounced in invading monocytes/macrophages from lungs of patients with Global Initiative for Obstructive Lung Disease (GOLD) stage IV COPD. Given this expression pattern, the functional role of CCR8 on human macrophages was evaluated in vitro. Human peripheral blood monocytes expressed low levels of CCR8, while macrophage colony-stimulating factor (M-CSF)-derived human macrophages expressed significantly elevated surface levels of CCR8. Importantly, CCL1 directly regulated the expression of CD18 and CD49b and hence influenced the adhesion capacity of human macrophages. CCL1 drives chemotaxis in M-CSF-derived macrophages, and this could be completely inhibited by lipopolysaccharide (LPS). Whereas both CCL1 and LPS monotreatment inhibited spontaneous superoxide release in macrophages, CCL1 significantly induced superoxide release in the presence of LPS in a dose-dependent manner. Finally, CCL1 induced production of proinflammatory cytokines such as tumor necrosis factor alpha (TNF-α) and interleukin-6 (IL-6) and could inhibit LPS-induced cytokine production in a dose-dependent manner. Our data demonstrate, for the first time, the presence of CCR8 on inflammatory macrophages in human COPD lung tissue. Importantly, the functional data from human macrophages suggest a potential cross talk between the CCR8 and the Toll-like receptor 4 (TLR4) pathways, both of which are present in COPD patients.

Activation of interferon regulatory factor-3 via toll-like receptor 3 and immunomodulatory functions detected in A549 lung epithelial cells exposed to misplaced U1-snRNA.

PubMed

Sadik, Christian D; Bachmann, Malte; Pfeilschifter, Josef; Mühl, Heiko

2009-08-01

U1-snRNA is an integral part of the U1 ribonucleoprotein pivotal for pre-mRNA splicing. Toll-like receptor (TLR) signaling has recently been associated with immunoregulatory capacities of U1-snRNA. Using lung A549 epithelial/carcinoma cells, we report for the first time on interferon regulatory factor (IRF)-3 activation initiated by endosomally delivered U1-snRNA. This was associated with expression of the IRF3-inducible genes interferon-beta (IFN-beta), CXCL10/IP-10 and indoleamine 2,3-dioxygenase. Mutational analysis of the U1-snRNA-activated IFN-beta promoter confirmed the crucial role of the PRDIII element, previously proven pivotal for promoter activation by IRF3. Notably, expression of these parameters was suppressed by bafilomycin A(1), an inhibitor of endosomal acidification, implicating endosomal TLR activation. Since resiquimod, an agonist of TLR7/8, failed to stimulate A549 cells, data suggest TLR3 to be of prime relevance for cellular activation. To assess the overall regulatory potential of U1-snRNA-activated epithelial cells on cytokine production, co-cultivation with peripheral blood mononuclear cells (PBMC) was performed. Interestingly, A549 cells activated by U1-snRNA reinforced phytohemagglutinin-induced interleukin-10 release by PBMC but suppressed that of tumor necrosis factor-alpha, indicating an anti-inflammatory potential of U1-snRNA. Since U1-snRNA is enriched in apoptotic bodies and epithelial cells are capable of performing efferocytosis, the present data in particular connect to immunobiological aspects of apoptosis at host/environment interfaces.

Primary Role for Toll-Like Receptor-Driven Tumor Necrosis Factor Rather than Cytosolic Immune Detection in Restricting Coxiella burnetii Phase II Replication within Mouse Macrophages

PubMed Central

Bradley, William P.; Boyer, Mark A.; Nguyen, Hieu T.; Birdwell, L. Dillon; Yu, Janet; Ribeiro, Juliana M.; Roy, Craig R.

2016-01-01

Coxiella burnetii replicates within permissive host cells by employing a Dot/Icm type IV secretion system (T4SS) to translocate effector proteins that direct the formation of a parasitophorous vacuole. C57BL/6 mouse macrophages restrict the intracellular replication of the C. burnetii Nine Mile phase II (NMII) strain. However, eliminating Toll-like receptor 2 (TLR2) permits bacterial replication, indicating that the restriction of bacterial replication is immune mediated. Here, we examined whether additional innate immune pathways are employed by C57BL/6 macrophages to sense and restrict NMII replication. In addition to the known role of TLR2 in detecting and restricting NMII infection, we found that TLR4 also contributes to cytokine responses but is not required to restrict bacterial replication. Furthermore, the TLR signaling adaptors MyD88 and Trif are required for cytokine responses and restricting bacterial replication. The C. burnetii NMII T4SS translocates bacterial products into C57BL/6 macrophages. However, there was little evidence of cytosolic immune sensing of NMII, as there was a lack of inflammasome activation, T4SS-dependent cytokine responses, and robust type I interferon (IFN) production, and these pathways were not required to restrict bacterial replication. Instead, endogenous tumor necrosis factor (TNF) produced upon TLR sensing of C. burnetii NMII was required to control bacterial replication. Therefore, our findings indicate a primary role for TNF produced upon immune detection of C. burnetii NMII by TLRs, rather than cytosolic PRRs, in enabling C57BL/6 macrophages to restrict bacterial replication. PMID:26787725

Toll-like receptor 4 in glial inflammatory responses to air pollution in vitro and in vivo.

PubMed

Woodward, Nicholas C; Levine, Morgan C; Haghani, Amin; Shirmohammadi, Farimah; Saffari, Arian; Sioutas, Constantinos; Morgan, Todd E; Finch, Caleb E

2017-04-14

Exposure to traffic-related air pollution (TRAP) is associated with accelerated cognitive aging and higher dementia risk in human populations. Rodent brains respond to TRAP with activation of astrocytes and microglia, increased inflammatory cytokines, and neurite atrophy. A role for Toll-like receptor 4 (TLR4) was suggested in mouse TLR4-knockouts, which had attenuated lung macrophage responses to air pollution. To further analyze these mechanisms, we examined mixed glial cultures (astrocytes and microglia) for RNA responses to nanoscale particulate matter (nPM; diameter <0.2 μm), a well-characterized nanoscale particulate matter subfraction of TRAP collected from a local freeway (Morgan et al. Environ Health Perspect 2011; 119,1003-1009, 2011). The nPM was compared with responses to the endotoxin lipopolysaccharide (LPS), a classic TLR4 ligand, using Affymetrix whole genome microarray in rats. Expression patterns were analyzed by significance analysis of microarrays (SAM) for fold change and by weighted gene co-expression network analysis (WGCNA) to identify modules of shared responses between nPM and LPS. Finally, we examined TLR4 activation in hippocampal tissue from mice chronically exposed to nPM. SAM and WGCNA analyses showed strong activation of TLR4 and NF-κB by both nPM and LPS. TLR4 siRNA attenuated TNFα and other inflammatory responses to nPM in vitro, via the MyD88-dependent pathway. In vivo, mice chronically exposed to nPM showed increased TLR4, MyD88, TNFα, and TNFR2 RNA, and decreased NF-κB and TRAF6 RNA TLR4 and NF-κB responses in the hippocampus. These results show TLR4 activation is integral in brain inflammatory responses to air pollution, and warrant further study of TLR4 in accelerated cognitive aging by air pollution.

Missouri toll feasibility study : phase I

DOT National Transportation Integrated Search

2002-05-01

The purpose of this toll feasibility study is to estimate the potential revenue that could be generated from several candidate toll projects within the state. Potential toll revenue may then be considered in combination with other possible funding me...

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

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.

Proteolytic Cascade for the Activation of the Insect Toll Pathway Induced by the Fungal Cell Wall Component

PubMed Central

Roh, Kyung-Baeg; Kim, Chan-Hee; Lee, Hanna; Kwon, Hyun-Mi; Park, Ji-Won; Ryu, Ji-Hwan; Kurokawa, Kenji; Ha, Nam-Chul; Lee, Won-Jae; Lemaitre, Bruno; Söderhäll, Kenneth; Lee, Bok-Luel

2009-01-01

The insect Toll signaling pathway is activated upon recognition of Gram-positive bacteria and fungi, resulting in the expression of antimicrobial peptides via NF-κB-like transcription factor. This activation is mediated by a serine protease cascade leading to the processing of Spätzle, which generates the functional ligand of the Toll receptor. Recently, we identified three serine proteases mediating Toll pathway activation induced by lysine-type peptidoglycan of Gram-positive bacteria. However, the identities of the downstream serine protease components of Gram-negative-binding protein 3 (GNBP3), a receptor for a major cell wall component β-1,3-glucan of fungi, and their order of activation have not been characterized yet. Here, we identified three serine proteases that are required for Toll activation by β-1,3-glucan in the larvae of a large beetle, Tenebrio molitor. The first one is a modular serine protease functioning immediately downstream of GNBP3 that proteolytically activates the second one, a Spätzle-processing enzyme-activating enzyme that in turn activates the third serine protease, a Spätzle-processing enzyme. The active form of Spätzle-processing enzyme then cleaves Spätzle into the processed Spätzle as Toll ligand. In addition, we show that injection of β-1,3-glucan into Tenebrio larvae induces production of two antimicrobial peptides, Tenecin 1 and Tenecin 2, which are also inducible by injection of the active form of Spätzle-processing enzyme-activating enzyme or processed Spätzle. These results demonstrate a three-step proteolytic cascade essential for the Toll pathway activation by fungal β-1,3-glucan in Tenebrio larvae, which is shared with lysine-type peptidoglycan-induced Toll pathway activation. PMID:19473968

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.

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

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

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

Dynamic Toll-like receptor expression predicts outcome of sclerotherapy for lymphatic malformations with OK-432 in children.

PubMed

Reismann, Marc; Ghaffarpour, Nader; Luvall, Ethel; Jirmo, Adan C; Winqvist, Ola; Radtke, Josephine; Wester, Tomas; Claesson, Gösta

2014-03-01

Sclerotherapy with OK-432 is recommended as a first-line treatment for lymphatic malformations. However, 40% of patients show poor response, defined by involution to <50% of the original size. It has been suggested that the OK-432 effect is highly dependent on the Toll-like receptor (TLR) 4-dependent expression of TLR7 in antigen-presenting cells. We hypothesized that the ability for TLR expression in monocytes after treatment with the TLR4-ligand lipopolysaccharide (LPS) can be used to predict successful OK-432 treatment. Blood was taken from children with low responder (LR, n = 6) and high responder (HR, n = 5) of previous OK-432 treatment. Monocytes were stimulated with LPS for 20 h. TLR expression was analyzed with fluorescence-activated cell sorting (mean fluorescence intensity). The level of significance was P ≤ 0.05. The mean age of patients in the HR group was 1.4 ± 0.9 y and in the LR group 2.8 ± 2.9 y (P = 0.31). The mean TLR4 upregulation after LPS stimulation in the HR group was significantly higher than in the LR group (factor 3.6 versus factor 1 compared with nonstimulated controls; P = 0.037). The mean TLR7 expression did not show significant differences between the groups. Dynamic TLR4 expression represents most probably a predictive parameter for the treatment of lymphatic malformations with OK-432 and should be further investigated. Copyright © 2014 Elsevier Inc. All rights reserved.

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

Rational modulation of the innate immune system for neuroprotection in ischemic stroke

PubMed Central

Amantea, Diana; Micieli, Giuseppe; Tassorelli, Cristina; Cuartero, María I.; Ballesteros, Iván; Certo, Michelangelo; Moro, María A.; Lizasoain, Ignacio; Bagetta, Giacinto

2015-01-01

The innate immune system plays a dualistic role in the evolution of ischemic brain damage and has also been implicated in ischemic tolerance produced by different conditioning stimuli. Early after ischemia, perivascular astrocytes release cytokines and activate metalloproteases (MMPs) that contribute to blood–brain barrier (BBB) disruption and vasogenic oedema; whereas at later stages, they provide extracellular glutamate uptake, BBB regeneration and neurotrophic factors release. Similarly, early activation of microglia contributes to ischemic brain injury via the production of inflammatory cytokines, including tumor necrosis factor (TNF) and interleukin (IL)-1, reactive oxygen and nitrogen species and proteases. Nevertheless, microglia also contributes to the resolution of inflammation, by releasing IL-10 and tumor growth factor (TGF)-β, and to the late reparative processes by phagocytic activity and growth factors production. Indeed, after ischemia, microglia/macrophages differentiate toward several phenotypes: the M1 pro-inflammatory phenotype is classically activated via toll-like receptors or interferon-γ, whereas M2 phenotypes are alternatively activated by regulatory mediators, such as ILs 4, 10, 13, or TGF-β. Thus, immune cells exert a dualistic role on the evolution of ischemic brain damage, since the classic phenotypes promote injury, whereas alternatively activated M2 macrophages or N2 neutrophils prompt tissue remodeling and repair. Moreover, a subdued activation of the immune system has been involved in ischemic tolerance, since different preconditioning stimuli act via modulation of inflammatory mediators, including toll-like receptors and cytokine signaling pathways. This further underscores that the immuno-modulatory approach for the treatment of ischemic stroke should be aimed at blocking the detrimental effects, while promoting the beneficial responses of the immune reaction. PMID:25972779

47 CFR 63.65 - Closure of public toll station where another toll station of applicant in the community will...

Code of Federal Regulations, 2014 CFR

2014-10-01

... 47 Telecommunication 3 2014-10-01 2014-10-01 false Closure of public toll station where another toll station of applicant in the community will continue service. 63.65 Section 63.65 Telecommunication... of public toll station where another toll station of applicant in the community will continue service...

47 CFR 63.65 - Closure of public toll station where another toll station of applicant in the community will...

Code of Federal Regulations, 2011 CFR

2011-10-01

... 47 Telecommunication 3 2011-10-01 2011-10-01 false Closure of public toll station where another toll station of applicant in the community will continue service. 63.65 Section 63.65 Telecommunication... of public toll station where another toll station of applicant in the community will continue service...

47 CFR 63.65 - Closure of public toll station where another toll station of applicant in the community will...

Code of Federal Regulations, 2012 CFR

2012-10-01

... 47 Telecommunication 3 2012-10-01 2012-10-01 false Closure of public toll station where another toll station of applicant in the community will continue service. 63.65 Section 63.65 Telecommunication... of public toll station where another toll station of applicant in the community will continue service...

47 CFR 63.65 - Closure of public toll station where another toll station of applicant in the community will...

Code of Federal Regulations, 2013 CFR

2013-10-01

... 47 Telecommunication 3 2013-10-01 2013-10-01 false Closure of public toll station where another toll station of applicant in the community will continue service. 63.65 Section 63.65 Telecommunication... of public toll station where another toll station of applicant in the community will continue service...

47 CFR 63.65 - Closure of public toll station where another toll station of applicant in the community will...

Code of Federal Regulations, 2010 CFR

2010-10-01

... 47 Telecommunication 3 2010-10-01 2010-10-01 false Closure of public toll station where another toll station of applicant in the community will continue service. 63.65 Section 63.65 Telecommunication... of public toll station where another toll station of applicant in the community will continue service...

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.

Influence of toll-like receptor 4 gene variants and plasma fatty acid profile on systemic inflammation: A population-based cross-sectional study.

PubMed

Norde, Marina Maintinguer; Oki, Erica; Carioca, Antonio A F; Castro, Inar A; Souza, José M P; Marchioni, Dirce M L; Fisberg, Regina M; Rogero, Marcelo M

2017-03-01

The aim of this study was to investigate the interaction of toll-like receptor 4 (TLR4) gene single nucleotide polymorphism (SNP) and plasma fatty acid (FA) profile in modulating risk for systemic inflammation. In all, 262 adult (19-59 y) participants of the Health Survey of São Paulo met the inclusion criteria. Anthropometric parameters, blood pressure, plasma inflammatory biomarker concentration, and fatty acid profile were measured and four SNPs of the TLR4 gene (rs4986790, rs4986791, rs11536889, and rs5030728) were genotyped. Multivariate cluster analysis was performed to stratify individuals based on levels of 11 plasma inflammatory biomarkers into two groups: inflammatory (INF) and noninflammatory (NINF). No association was found between any of the SNPs studied and systemic inflammation. The INF cluster had higher palmitic acid levels (P = 0.039) and estimated stearoyl coenzyme A desaturase activity (P = 0.045) and lower polyunsaturated fatty acid (P = 0.011), ω-6 fatty acid (P = 0.018), arachidonic acid (P = 0.002) levels, and estimated δ-5 desaturase activity (P = 0.025) compared with the NINF cluster. Statistically significant interaction between rs11536889 and arachidonic acid/eicosapentaenoic acid (AA/EPA) ratio (P = 0.034) was found to increase the odds of belonging to the INF cluster when individuals had the variant allele C and were at the higher percentile of AA/EPA plasma ratio. Plasma fatty acid profile modulated the odds of belonging to the INF cluster depending on genotypes of TRL4 gene polymorphisms. Copyright © 2016 Elsevier Inc. All rights reserved.

Toll-like receptor-5 agonist, entolimod, suppresses metastasis and induces immunity by stimulating an NK-dendritic-CD8+ T-cell axis

PubMed Central

Brackett, Craig M.; Kojouharov, Bojidar; Veith, Jean; Greene, Kellee F.; Burdelya, Lyudmila G.; Gollnick, Sandra O.; Abrams, Scott I.; Gudkov, Andrei V.

2016-01-01

Activation of an anticancer innate immune response is highly desirable because of its inherent ability to generate an adaptive antitumor T-cell response. However, insufficient safety of innate immune modulators limits clinical use to topical applications. Toll-like receptor 5 (TLR5) agonists are favorably positioned as potential systemic immunotherapeutic agents because of unusual tissue specificity of expression, uniquely safe profile of induced cytokines, and antitumor efficacy demonstrated in a number of animal models. Here, we decipher the molecular and cellular events underlying the metastasis suppressive activity of entolimod, a clinical stage TLR5 agonist that activates NF-κB–, AP-1–, and STAT3–driven immunomodulatory signaling pathways specifically within the liver. Used as a single agent in murine colon and mammary metastatic cancer models, entolimod rapidly induces CXCL9 and -10 that support homing of blood-borne CXCR3-expressing NK cells to the liver predominantly through an IFN-γ signaling independent mechanism. NK cell-dependent activation of dendritic cells is followed by stimulation of a CD8+ T-cell response, which exert both antimetastatic effect of entolimod and establishment of tumor-specific and durable immune memory. These results define systemically administered TLR5 agonists as organ-specific immunoadjuvants, enabling efficient antitumor vaccination that does not depend on identification of tumor-specific antigens. PMID:26831100

Kelch-like ECH-associated Protein 1-dependent Nuclear Factor-E2-related Factor 2 Activation in Relation to Antioxidation Induced by Sevoflurane Preconditioning.

PubMed

Cai, Min; Tong, Li; Dong, Beibei; Hou, Wugang; Shi, Likai; Dong, Hailong

2017-03-01

The authors have reported that antioxidative effects play a crucial role in the volatile anesthetic-induced neuroprotection. Accumulated evidence shows that endogenous antioxidation could be up-regulated by nuclear factor-E2-related factor 2 through multiple pathways. However, whether nuclear factor-E2-related factor 2 activation is modulated by sevoflurane preconditioning and, if so, what is the signaling cascade underlying upstream of this activation are still unknown. Sevoflurane preconditioning in mice was performed with sevoflurane (2.5%) 1 h per day for five consecutive days. Focal cerebral ischemia/reperfusion injury was induced by middle cerebral artery occlusion. Expression of nuclear factor-E2-related factor 2, kelch-like ECH-associated protein 1, manganese superoxide dismutase, thioredoxin-1, and nicotinamide adenine dinucleotide phosphate quinolone oxidoreductase-1 was detected (n = 6). The antioxidant activities and oxidative product expression were also examined. To determine the role of kelch-like ECH-associated protein 1 inhibition-dependent nuclear factor-E2-related factor 2 activation in sevoflurane preconditioning-induced neuroprotection, the kelch-like ECH-associated protein 1-nuclear factor-E2-related factor 2 signal was modulated by nuclear factor-E2-related factor 2 knockout, kelch-like ECH-associated protein 1 overexpression lentivirus, and kelch-like ECH-associated protein 1 deficiency small interfering RNA (n = 8). The infarct volume, neurologic scores, and cellular apoptosis were assessed. Sevoflurane preconditioning elicited neuroprotection and increased nuclear factor-E2-related factor 2 nuclear translocation, which in turn up-regulated endogenous antioxidation and reduced oxidative injury. Sevoflurane preconditioning reduced kelch-like ECH-associated protein 1 expression. Nuclear factor-E2-related factor 2 ablation abolished neuroprotection and reversed sevoflurane preconditioning by mediating the up-regulation of antioxidants. Kelch-like

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

Concentrations of ultrafine particles at a highway toll collection booth and exposure implications for toll collectors.

PubMed

Cheng, Yu-Hsiang; Huang, Cheng-Hsiung; Huang, Hsiao-Lin; Tsai, Chuen-Jinn

2010-12-15

Research regarding the magnitude of ultrafine particle levels at highway toll stations is limited. This study measured ambient concentrations of ultrafine particles at a highway toll station from October 30 to November 1 and November 5 to November 6, 2008. A scanning mobility particle sizer was used to measure ultrafine particle concentrations at a ticket/cash tollbooth. Levels of hourly average ultrafine particles at the tollbooth were about 3-6 times higher than those in urban backgrounds, indicating that a considerable amount of ultrafine particles are exhausted from passing vehicles. A bi-modal size distribution pattern with a dominant mode at about <6 nm and a minor mode at about 40 nm was observed at the tollbooth. The high amounts of nanoparticles in this study can be attributed to gas-to-particle reactions in fresh fumes emitted directly from vehicles. The influences of traffic volume, wind speed, and relative humidity on ultrafine particle concentrations were also determined. High ambient concentrations of ultrafine particles existed under low wind speed, low relative humidity, and high traffic volume. Although different factors account for high ambient concentrations of ultrafine particles at the tollbooth, measurements indicate that toll collectors who work close to traffic emission sources have a high exposure risk. Copyright © 2010 Elsevier B.V. All rights reserved.

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.

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.

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

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

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.

Innate immune interactions within the central nervous system modulate pathogenesis of viral infections

PubMed Central

Nair, Sharmila; Diamond, Michael S.

2015-01-01

The innate immune system mediates protection against neurotropic viruses that replicate in the central nervous system (CNS). Virus infection within specific cells of the CNS triggers activation of several families of pattern recognition receptors including Toll-like receptors, retinoic acid-inducible gene 1 like receptors, nucleotide-binding oligomerization domain-like receptors, and cytosolic DNA sensors. In this review, we highlight recent advances in our understanding of how cell-intrinsic host defenses within the CNS modulate infection of different DNA and RNA viruses. PMID:26163762

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.

Novel critical role of Toll-like receptor 4 in lung ischemia-reperfusion injury and edema

PubMed Central

Zanotti, Giorgio; Casiraghi, Monica; Abano, John B.; Tatreau, Jason R.; Sevala, Mayura; Berlin, Hilary; Smyth, Susan; Funkhouser, William K.; Burridge, Keith; Randell, Scott H.; Egan, Thomas M.

2009-01-01

Toll-like receptors (TLRs) of the innate immune system contribute to noninfectious inflammatory processes. We employed a murine model of hilar clamping (1 h) with reperfusion times between 15 min and 3 h in TLR4-sufficient (C3H/OuJ) and TLR4-deficient (C3H/HeJ) anesthetized mice with additional studies in chimeric and myeloid differentiation factor 88 (MyD88)- and TLR4-deficient mice to determine the role of TLR4 in lung ischemia-reperfusion injury. Human pulmonary microvascular endothelial monolayers were subjected to simulated warm ischemia and reperfusion with and without CRX-526, a competitive TLR4 inhibitor. Functional TLR4 solely on pulmonary parenchymal cells, not bone marrow-derived cells, mediates early lung edema following ischemia-reperfusion independent of MyD88. Activation of MAPKs and NF-κB was significantly blunted and/or delayed in lungs of TLR4-deficient mice as a consequence of ischemia-reperfusion injury, but edema development appeared to be independent of activation of these signaling pathways. Pretreatment with a competitive TLR4 inhibitor prevented edema in vivo and reduced actin cytoskeletal rearrangement and gap formation in pulmonary microvascular endothelial monolayers subjected to simulated warm ischemia and reperfusion. In addition to its well-accepted role to alter gene transcription, functioning TLR4 on pulmonary parenchymal cells plays a key role in very early and profound pulmonary edema in murine lung ischemia-reperfusion injury. This may be due to a novel mechanism: regulation of endothelial cell cytoskeleton affecting microvascular endothelial cell permeability. PMID:19376887

Regiospecific Methylation of a Dietary Flavonoid Scaffold Selectively Enhances IL-1β Production following Toll-like Receptor 2 Stimulation in THP-1 Monocytes*

PubMed Central

Lim, Eng-Kiat; Mitchell, Paul J.; Brown, Najmeeyah; Drummond, Rebecca A.; Brown, Gordon D.; Kaye, Paul M.; Bowles, Dianna J.

2013-01-01

It is now recognized that innate immunity to intestinal microflora plays a significant role in mediating immune health, and modulation of microbial sensing may underpin the impact of plant natural products in the diet or when used as nutraceuticals. In this context, we have examined five classes of plant-derived flavonoids (flavonols, flavones, flavanones, catechins, and cyanidin) for their ability to regulate cytokine release induced by the Toll-like receptor 2 (TLR2) agonist Pam3CSK4. We found that the flavonols selectively co-stimulated IL-1β secretion but had no impact on the secretion of IL-6. Importantly, this costimulation of TLR2-induced cytokine secretion was dependent on regiospecific methylation of the flavonol scaffold with a rank order of quercetin-3,4′-dimethylether > quercetin-3-methylether > casticin. The mechanism underpinning this costimulation did not involve enhanced inflammasome activation. In contrast, the methylated flavonols enhanced IL-1β gene expression through transcriptional regulation, involving mechanisms that operate downstream of the initial NF-κB and STAT1 activation events. These studies demonstrate an exquisite level of control of scaffold bioactivity by regiospecific methylation, with important implications for understanding how natural products affect innate immunity and for their development as novel immunomodulators for clinical use. PMID:23760261

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.

Kruppel-like Factor 4 Protein Regulates Isoproterenol-induced Cardiac Hypertrophy by Modulating Myocardin Expression and Activity*

PubMed Central

Yoshida, Tadashi; Yamashita, Maho; Horimai, Chihiro; Hayashi, Matsuhiko

2014-01-01

Kruppel-like factor 4 (KLF4) plays an important role in vascular diseases, including atherosclerosis and vascular injury. Although KLF4 is expressed in the heart in addition to vascular cells, the role of KLF4 in cardiac disease has not been fully determined. The goals of this study were to investigate the role of KLF4 in cardiac hypertrophy and to determine the underlying mechanisms. Cardiomyocyte-specific Klf4 knockout (CM Klf4 KO) mice were generated by the Cre/LoxP technique. Cardiac hypertrophy was induced by chronic infusion of the β-adrenoreceptor agonist isoproterenol (ISO). Results showed that ISO-induced cardiac hypertrophy was enhanced in CM Klf4 KO mice compared with control mice. Accelerated cardiac hypertrophy in CM Klf4 KO mice was accompanied by the augmented cellular enlargement of cardiomyocytes as well as the exaggerated expression of fetal cardiac genes, including atrial natriuretic factor (Nppa). Additionally, induction of myocardin, a transcriptional cofactor regulating fetal cardiac genes, was enhanced in CM Klf4 KO mice. Interestingly, KLF4 regulated Nppa expression by modulating the expression and activity of myocardin, providing a mechanical basis for accelerated cardiac hypertrophy in CM Klf4 KO mice. Moreover, we showed that KLF4 mediated the antihypertrophic effect of trichostatin A, a histone deacetylase inhibitor, because ISO-induced cardiac hypertrophy in CM Klf4 KO mice was attenuated by olmesartan, an angiotensin II type 1 antagonist, but not by trichostatin A. These results provide novel evidence that KLF4 is a regulator of cardiac hypertrophy by modulating the expression and the activity of myocardin. PMID:25100730

Intestinal Epithelial Toll-Like Receptor 4 Signaling Affects Epithelial Function and Colonic Microbiota and Promotes a Risk for Transmissible Colitis

PubMed Central

Dheer, Rishu; Santaolalla, Rebeca; Davies, Julie M.; Lang, Jessica K.; Phillips, Matthew C.; Pastorini, Cristhine; Vazquez-Pertejo, Maria T.

2016-01-01

Evidence obtained from gene knockout studies supports the role of Toll-like receptor 4 (TLR4) in intestinal inflammation and microbiota recognition. Increased epithelial TLR4 expression is observed in patients with inflammatory bowel disease. However, little is known of the effect of increased TLR4 signaling on intestinal homeostasis. Here, we examined the effect of increased TLR4 signaling on epithelial function and microbiota by using transgenic villin-TLR4 mice that overexpress TLR4 in the intestinal epithelium. Our results revealed that villin-TLR4 mice are characterized by increases in the density of mucosa-associated bacteria and bacterial translocation. Furthermore, increased epithelial TLR4 signaling was associated with an impaired epithelial barrier, altered expression of antimicrobial peptide genes, and altered epithelial cell differentiation. The composition of the colonic luminal and mucosa-associated microbiota differed between villin-TLR4 and wild-type (WT) littermates. Interestingly, WT mice cohoused with villin-TLR4 mice displayed greater susceptibility to acute colitis than singly housed WT mice did. The results of this study suggest that epithelial TLR4 expression shapes the microbiota and affects the functional properties of the epithelium. The changes in the microbiota induced by increased epithelial TLR4 signaling are transmissible and exacerbate dextran sodium sulfate-induced colitis. Together, our findings imply that host innate immune signaling can modulate intestinal bacteria and ultimately the host's susceptibility to colitis. PMID:26755160

Effects of Toll-like receptor 3 on herpes simplex virus type-1-infected mouse neural stem cells.

PubMed

Sun, Xiuning; Shi, Lihong; Zhang, Haoyun; Li, Ruifang; Liang, Ruiwen; Liu, Zhijun

2015-03-01

In this study, we aimed to investigate the effect of herpes simplex virus type-1 (HSV-1) infection on the phosphorylation of interferon regulatory factor 3 (IRF3) and the expression of interferon-β (IFN-β), as well as to clarify the functions of toll-like receptor 3 (TLR3) in mouse neural stem cells (NSCs) infected with HSV-1. In HSV-1-infected cultured NSCs, immunofluorescence, reverse transcription - polymerase chain reaction, Western blot, and ELISA were performed to reveal the expression patterns of TLR3, IRF3, and IFN-β. Then, lentivirus-mediated RNA interference (RNAi) was used to block the expression of TLR3, and its effect on host resistance to HSV-1 infection was investigated. Under uninfected conditions, NSCs expressed TLR3 and phosphorylated IRF3, but after infection, the expression level of TLR3 was upregulated and the phosphorylation level of IRF3 in the nucleus was significantly enhanced, while IFN-β was also expressed. After TLR3 expression was blocked by lentivirus-mediated RNAi, IRF3 phosphorylation and IFN-β expression were downregulated. Therefore, HSV-1 upregulated the expression of TLR3 in NSCs and promoted nuclear translocation after IRF3 was phosphorylated to induce IFN-β expression. TLR3 exhibited an anti-HSV-1 infection capacity via innate immune functions.

Toll-like receptor 3 deficiency decreases epileptogenesis in a pilocarpine model of SE-induced epilepsy in mice.

PubMed

Gross, Adi; Benninger, Felix; Madar, Ravit; Illouz, Tomer; Griffioen, Kathleen; Steiner, Israel; Offen, Daniel; Okun, Eitan

2017-04-01

Epilepsy affects 60 million people worldwide. Despite the development of antiepileptic drugs, up to 35% of patients are drug refractory with uncontrollable seizures. Toll-like receptors (TLRs) are central components of the nonspecific innate inflammatory response. Because TLR3 was recently implicated in neuronal plasticity, we hypothesized that it may contribute to the development of epilepsy after status epilepticus (SE). To test the involvement of TLR3 in epileptogenesis, we used the pilocarpine model for SE in TLR3-deficient mice and their respective wild-type controls. In this model, a single SE event leads to spontaneous recurrent seizures (SRS). Two weeks after SE, mice were implanted with wireless electroencephalography (EEG) transmitters for up to 1 month. The impact of TLR3 deficiency on SE was assessed using separate cohorts of mice regarding EEG activity, seizure progression, hippocampal microglial distribution, and expression of the proinflammatory cytokines tumor necrosis factor (TNF)α and interferon (IFN)β. Our data indicate that TLR3 deficiency reduced SRS, microglial activation, and the levels of the proinflammatory cytokines TNFα and IFNβ, and increased survival following SE. This study reveals novel insights into the pathophysiology of epilepsy and the contribution of TLR3 to disease progression. Our results identify the TLR3 pathway as a potential future therapeutic target in SE. Wiley Periodicals, Inc. © 2017 International League Against Epilepsy.

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.

Decreased expression of Toll-like receptor 4 and 5 during progression of prostate transformation in transgenic adenocarcinoma of mouse prostate mice.

PubMed

Han, Ju-Hee; Park, Jong-Hwan; Kim, Bo-Yeon; Chang, Seo-Na; Kim, Tae-Hyoun; Park, Jae-Hak; Kim, Dong-Jae

2015-01-01

Chronic inflammation has been considered an important risk factor for development of prostate cancer. Toll-like receptors (TLRs) recognize microbial moieties or endogenous molecules and play an important role in the triggering and promotion of inflammation. In this study, we examined whether expression of TLR4 and TLR5 was associated with progression of prostate transformation in the transgenic adenocarcinoma of mouse prostate (TRAMP) model. The expression of TLR4 and TLR5 was evaluated by immunohistochemisty in formalin-fixed paraffin-embedded prostate tissue from wild-type (WT) and TRAMP mice. Normal prostate tissue from WT mice showed strong expression of TLR4 and TLR5. However, TLR4 expression in the prostate tissue from TRAMP mice gradually decreased as pathologic grade became more aggressive. TLR5 expression in the prostate tissue from TRAMP mice also decreased in low-grade prostate intraepithelial neoplasia (PIN), high-grade PIN and poorly differentiated adenocarcinoma. Overall, our results suggest that decreased expression of TLR4 and TLR5 may contribute to prostate tumorigenesis.

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

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

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

Toll-Like Receptor 3 Signaling Contributes to Regional Neutrophil Recruitment in Cultured Human Glomerular Endothelial Cells.

PubMed

Liu, Qiang; Imaizumi, Tadaatsu; Kawaguchi, Shogo; Aizawa, Tomomi; Matsumiya, Tomoh; Watanabe, Shojiro; Tsugawa, Koji; Yoshida, Hidemi; Tsuruga, Kazushi; Joh, Kensuke; Kijima, Hiroshi; Tanaka, Hiroshi

2018-05-23

Given the importance of neutrophil recruitment in the pathogenesis of glomerulonephritis (GN), the representative neutrophil chemoattractant C-X-C motif chemokine 1 (CXCL1)/GROα and the adhesion molecule E-selectin in glomerular endothelial cells (GECs) play a pivotal role in the development of GN. Endothelial Toll-like receptor 3 (TLR3) is thought to be involved in the inflammatory response via innate immunity. However, the role of endothelial TLR3 signaling in the expression of neutrophil chemoattractants and adhesion molecules remains to be elucidated. Thus, we aimed to examine this issue. We treated normal human GECs with polyinosinic-polycytidylic acid (poly IC), an authentic double-stranded RNA, and analyzed the expressions of CXCL1 and E-selectin using quantitative real-time reverse transcription-polymerase chain reaction, western blotting, and enzyme-linked immunosorbent assay. To further elucidate the poly IC-induced signaling pathway, we subjected the cells to RNA interference against TLR3, interferon (IFN)-β, nuclear factor (NF)-κB p65, and IFN regulatory factor (IRF) 3. We also used immunofluorescence to examine the endothelial expression of CXCL1 in biopsy specimens from patients with crescentic and non-crescentic purpura nephritis (PN). We found that the activation of TLR3 induced the endothelial expression of CXCL1 and E-selectin, and that this involved TLR3, -NF-κB, IRF3, and IFN-β. Intense endothelial CXCL1 expression was observed in biopsy specimens from patients with crescentic PN. These findings support a role for glomerular antiviral innate immunity in the pathogenesis of GN. Intervention of glomerular TLR3 signaling may therefore be a suitable therapeutic strategy for treating GN in the future. © 2018 S. Karger AG, Basel.

CCR8 Signaling Influences Toll-Like Receptor 4 Responses in Human Macrophages in Inflammatory Diseases ▿

PubMed Central

Kvist Reimer, Martina; Brange, Charlotte; Rosendahl, Alexander

2011-01-01

CCR8 immunity is generally associated with Th2 responses in allergic diseases. In this study, we demonstrate for the first time a pronounced attenuated influx of macrophages in ovalbumin (OVA)-challenged CCR8 knockout mice. To explore whether macrophages in human inflamed lung tissue also were CCR8 positive, human lung tissue from patients with chronic obstructive pulmonary disease (COPD) was evaluated. Indeed, CCR8 expression was pronounced in invading monocytes/macrophages from lungs of patients with Global Initiative for Obstructive Lung Disease (GOLD) stage IV COPD. Given this expression pattern, the functional role of CCR8 on human macrophages was evaluated in vitro. Human peripheral blood monocytes expressed low levels of CCR8, while macrophage colony-stimulating factor (M-CSF)-derived human macrophages expressed significantly elevated surface levels of CCR8. Importantly, CCL1 directly regulated the expression of CD18 and CD49b and hence influenced the adhesion capacity of human macrophages. CCL1 drives chemotaxis in M-CSF-derived macrophages, and this could be completely inhibited by lipopolysaccharide (LPS). Whereas both CCL1 and LPS monotreatment inhibited spontaneous superoxide release in macrophages, CCL1 significantly induced superoxide release in the presence of LPS in a dose-dependent manner. Finally, CCL1 induced production of proinflammatory cytokines such as tumor necrosis factor alpha (TNF-α) and interleukin-6 (IL-6) and could inhibit LPS-induced cytokine production in a dose-dependent manner. Our data demonstrate, for the first time, the presence of CCR8 on inflammatory macrophages in human COPD lung tissue. Importantly, the functional data from human macrophages suggest a potential cross talk between the CCR8 and the Toll-like receptor 4 (TLR4) pathways, both of which are present in COPD patients. PMID:21976223

Ebola virus modulates transforming growth factor β signaling and cellular markers of mesenchyme-like transition in hepatocytes.

PubMed

Kindrachuk, Jason; Wahl-Jensen, Victoria; Safronetz, David; Trost, Brett; Hoenen, Thomas; Arsenault, Ryan; Feldmann, Friederike; Traynor, Dawn; Postnikova, Elena; Kusalik, Anthony; Napper, Scott; Blaney, Joseph E; Feldmann, Heinz; Jahrling, Peter B

2014-09-01

Ebola virus (EBOV) causes a severe hemorrhagic disease in humans and nonhuman primates, with a median case fatality rate of 78.4%. Although EBOV is considered a public health concern, there is a relative paucity of information regarding the modulation of the functional host response during infection. We employed temporal kinome analysis to investigate the relative early, intermediate, and late host kinome responses to EBOV infection in human hepatocytes. Pathway overrepresentation analysis and functional network analysis of kinome data revealed that transforming growth factor (TGF-β)-mediated signaling responses were temporally modulated in response to EBOV infection. Upregulation of TGF-β signaling in the kinome data sets correlated with the upregulation of TGF-β secretion from EBOV-infected cells. Kinase inhibitors targeting TGF-β signaling, or additional cell receptors and downstream signaling pathway intermediates identified from our kinome analysis, also inhibited EBOV replication. Further, the inhibition of select cell signaling intermediates identified from our kinome analysis provided partial protection in a lethal model of EBOV infection. To gain perspective on the cellular consequence of TGF-β signaling modulation during EBOV infection, we assessed cellular markers associated with upregulation of TGF-β signaling. We observed upregulation of matrix metalloproteinase 9, N-cadherin, and fibronectin expression with concomitant reductions in the expression of E-cadherin and claudin-1, responses that are standard characteristics of an epithelium-to-mesenchyme-like transition. Additionally, we identified phosphorylation events downstream of TGF-β that may contribute to this process. From these observations, we propose a model for a broader role of TGF-β-mediated signaling responses in the pathogenesis of Ebola virus disease. Ebola virus (EBOV), formerly Zaire ebolavirus, causes a severe hemorrhagic disease in humans and nonhuman primates and is the most

Toll-like receptor 4 knockout protects against anthrax lethal toxin-induced cardiac contractile dysfunction: role of autophagy.

PubMed

Kandadi, Machender R; Frankel, Arthur E; Ren, Jun

2012-10-01

Anthrax lethal toxin (LeTx) is known to induce circulatory shock and death, although the underlying mechanisms have not been elucidated. This study was designed to evaluate the role of toll-like receptor 4 (TLR4) in anthrax lethal toxin-induced cardiac contractile dysfunction. Wild-type (WT) and TLR4 knockout (TLR⁻/⁻) mice were challenged with lethal toxin (2 µg·g⁻¹, i.p.), and cardiac function was assessed 18 h later using echocardiography and edge detection. Small interfering RNA (siRNA) was employed to knockdown TLR4 receptor or class III PI3K in H9C2 myoblasts. GFP-LC3 puncta was used to assess autophagosome formation. Western blot analysis was performed to evaluate autophagy (LC3, Becline-1, Agt5 and Agt7) and endoplasmic reticulum (ER) stress (BiP, eIF2α and calreticulin). In WT mice, lethal toxin exposure induced cardiac contractile dysfunction, as evidenced by reduced fractional shortening, peak shortening, maximal velocity of shortening/re-lengthening, prolonged re-lengthening duration and intracellular Ca²⁺ derangement. These effects were significantly attenuated or absent in the TLR4 knockout mice. In addition, lethal toxin elicited autophagy in the absence of change in ER stress. Knockdown of TLR4 or class III PI3 kinase using siRNA but not the autophagy inhibitor 3-methyladenine significantly attenuated or inhibited lethal toxin-induced autophagy in H9C2 cells. Our results suggest that TLR4 may be pivotal in mediating the lethal cardiac toxicity induced by anthrax possibly through induction of autophagy. These findings suggest that compounds that negatively modulate TLR4 signalling and autophagy could be used to treat anthrax infection-induced cardiovascular complications. © 2012 The Authors. British Journal of Pharmacology © 2012 The British Pharmacological Society.

Toll-like receptor 4 knockout protects against anthrax lethal toxin-induced cardiac contractile dysfunction: role of autophagy

PubMed Central

Kandadi, Machender R; Frankel, Arthur E; Ren, Jun

2012-01-01

BACKGROUND AND PURPOSE Anthrax lethal toxin (LeTx) is known to induce circulatory shock and death, although the underlying mechanisms have not been elucidated. This study was designed to evaluate the role of toll-like receptor 4 (TLR4) in anthrax lethal toxin-induced cardiac contractile dysfunction. EXPERIMENTAL APPROACH Wild-type (WT) and TLR4 knockout (TLR−/−) mice were challenged with lethal toxin (2 µg·g−1, i.p.), and cardiac function was assessed 18 h later using echocardiography and edge detection. Small interfering RNA (siRNA) was employed to knockdown TLR4 receptor or class III PI3K in H9C2 myoblasts. GFP–LC3 puncta was used to assess autophagosome formation. Western blot analysis was performed to evaluate autophagy (LC3, Becline-1, Agt5 and Agt7) and endoplasmic reticulum (ER) stress (BiP, eIF2α and calreticulin). KEY RESULTS In WT mice, lethal toxin exposure induced cardiac contractile dysfunction, as evidenced by reduced fractional shortening, peak shortening, maximal velocity of shortening/re-lengthening, prolonged re-lengthening duration and intracellular Ca2+ derangement. These effects were significantly attenuated or absent in the TLR4 knockout mice. In addition, lethal toxin elicited autophagy in the absence of change in ER stress. Knockdown of TLR4 or class III PI3 kinase using siRNA but not the autophagy inhibitor 3-methyladenine significantly attenuated or inhibited lethal toxin-induced autophagy in H9C2 cells. CONCLUSION AND IMPLICATIONS Our results suggest that TLR4 may be pivotal in mediating the lethal cardiac toxicity induced by anthrax possibly through induction of autophagy. These findings suggest that compounds that negatively modulate TLR4 signalling and autophagy could be used to treat anthrax infection-induced cardiovascular complications. PMID:22612289

Toll-Like Receptor 3 Is Critical for Coxsackievirus B4-Induced Type 1 Diabetes in Female NOD Mice

PubMed Central

Thuma, Jean R.; Courreges, Maria C.; Benencia, Fabian; James, Calvin B.L.; Malgor, Ramiro; Kantake, Noriko; Mudd, William; Denlinger, Nathan; Nolan, Bret; Wen, Li; Schwartz, Frank L.

2015-01-01

Group B coxsackieviruses (CVBs) are involved in triggering some cases of type 1 diabetes mellitus (T1DM). However, the molecular mechanism(s) responsible for this remain elusive. Toll-like receptor 3 (TLR3), a receptor that recognizes viral double-stranded RNA, is hypothesized to play a role in virus-induced T1DM, although this hypothesis is yet to be substantiated. The objective of this study was to directly investigate the role of TLR3 in CVB-triggered T1DM in nonobese diabetic (NOD) mice, a mouse model of human T1DM that is widely used to study both spontaneous autoimmune and viral-induced T1DM. As such, we infected female wild-type (TLR3+/+) and TLR3 knockout (TLR3−/−) NOD mice with CVB4 and compared the incidence of diabetes in CVB4-infected mice with that of uninfected counterparts. We also evaluated the islets of uninfected and CVB4-infected wild-type and TLR3 knockout NOD mice by immunohistochemistry and insulitis scoring. TLR3 knockout mice were markedly protected from CVB4-induced diabetes compared with CVB4-infected wild-type mice. CVB4-induced T-lymphocyte-mediated insulitis was also significantly less severe in TLR3 knockout mice compared with wild-type mice. No differences in insulitis were observed between uninfected animals, either wild-type or TLR3 knockout mice. These data demonstrate for the first time that TLR3 is 1) critical for CVB4-induced T1DM, and 2) modulates CVB4-induced insulitis in genetically prone NOD mice. PMID:25422874

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.

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.

47 CFR 52.111 - Toll free number assignment.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 47 Telecommunication 3 2013-10-01 2013-10-01 false Toll free number assignment. 52.111 Section 52.111 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES (CONTINUED) NUMBERING Toll Free Numbers § 52.111 Toll free number assignment. Toll free numbers shall be made available...

[Application of artificial neural networks in forecasting the number of circulatory system diseases death toll].

PubMed

Zhang, Ying; Shao, Yi; Shang, Kezheng; Wang, Shigong; Wang, Jinyan

2014-09-01

Set up the model of forecasting the number of circulatorys death toll based on back-propagation (BP) artificial neural networks discuss the relationship between the circulatory system diseases death toll meteorological factors and ambient air pollution. The data of tem deaths, meteorological factors, and ambient air pollution within the m 2004 to 2009 in Nanjing were collected. On the basis of analyzing the ficient between CSDDT meteorological factors and ambient air pollution, leutral network model of CSDDT was built for 2004 - 2008 based on factors and ambient air pollution within the same time, and the data of 2009 est the predictive power of the model. There was a closely system diseases relationship between meteorological factors, ambient air pollution and the circulatory system diseases death toll. The ANN model structure was 17 -16 -1, 17 input notes, 16 hidden notes and 1 output note. The training precision was 0. 005 and the final error was 0. 004 999 42 after 487 training steps. The results of forecast show that predict accuracy over 78. 62%. This method is easy to be finished with smaller error, and higher ability on circulatory system death toll on independent prediction, which can provide a new method for forecasting medical-meteorological forecast and have the value of further research.

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

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.

Investigate attractiveness of toll roads.

DOT National Transportation Integrated Search

2015-03-01

HOT facilities are used as a solution for congestion mitigation instead of constructing or expanding the capacity of : existing roadways. Although toll roads modeling has been researched for a long time, High Occupancy Toll (HOT) : modeling is relati...

Effect of smoking on the genetic makeup of toll-like receptors 2 and 6.

PubMed

Kohailan, Muhammad; Alanazi, Mohammad; Rouabhia, Mahmoud; Alamri, Abdullah; Parine, Narasimha Reddy; Alhadheq, Abdullah; Basavarajappa, Santhosh; Abdullah Al-Kheraif, Abdul Aziz; Semlali, Abdelhabib

2016-01-01

Cigarette smoking is a major risk factor for lung cancer, asthma, and oral cancer, and is central to the altered innate immune responsiveness to infection. Many hypotheses have provided evidence that cigarette smoking induces more genetic changes in genes involved in the development of many cigarette-related diseases. This alteration may be from single-nucleotide polymorphisms (SNPs) in innate immunity genes, especially the toll-like receptors (TLRs). In this study, the genotype frequencies of TLR2 and TLR6 in smoking and nonsmoking population were examined. Saliva samples were collected from 177 smokers and 126 nonsmokers. The SNPs used were rs3804100 (1350 T/C, Ser450Ser) and rs3804099 (597 T/C, Asn199Asn) for TLR2 and rs3796508 (979 G/A, Val327Met) and rs5743810 (745 T/C, Ser249Pro) for TLR6. Results showed that TLR2 rs3804100 has a significant effect in short-term smokers (OR =2.63; P =0.04), and this effect is not observed in long-term smokers (>5 years of smoking). Therefore, this early mutation may be repaired by the DNA repair system. For TLR2 rs3804099, the variation in genotype frequencies between the smokers and control patients was due to a late mutation, and its protective role appears only in long-term smokers (OR =0.40, P =0.018). In TLR6 rs5743810, the TT genotype is significantly higher in smokers than in nonsmokers (OR =6.90). The effect of this SNP is observed in long-term smokers, regardless of the smoking regime per day. TLR2 (rs3804100 and rs3804099) and TLR6 (rs5743810) can be used as a potential index in the diagnosis and prevention of more diseases caused by smoking.

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

Toll motorway accessibility for wheelchair users: a survey.

PubMed

Prigent, Hélène; Roche, Nicolas; Guillon, Bruno; Hurand, Anne; Moreau, Bernadette; Dufresne, Jean Pierre; Ravaud, Jean-François; Lofaso, Frédéric

2008-09-01

To identify difficulties encountered by wheelchair users who travel on toll motorways, with the goal of defining areas for improvement. Survey. After observing a wheelchair user travelling on a toll motorway and using the associated services, we designed a self-questionnaire on perceptions by wheelchair users of toll motorway accessibility. Toll motorway and rehabilitation hospital in France. We recruited 167 wheelchair users by advertisement and, to assess selection bias, 19 consecutive outpatients who visited our hospital's wheelchair showroom. None. Of the 186 included subjects, 91 (49%) were used to driving independently on toll motorways. Among them, only 16% used automatic toll booths and 32% reported difficulties at toll booths. Furthermore, 53% routinely asked for help at filling stations, and only 27% were aware of the availability of a free-of-charge assistance service for disabled people at some filling stations. Among the 186 toll motorway users, only 84 (45%) reported never encountering difficulties in lay-bys; 162 (87%) felt that toilet accessibility was the most important feature of lay-bys and 143 (77%) preferred the locked toilets reserved for disabled people. Wheelchair users reported difficulties on toll motorways that could be corrected fairly easily.

Drug repositioning for enzyme modulator based on human metabolite-likeness.

PubMed

Lee, Yoon Hyeok; Choi, Hojae; Park, Seongyong; Lee, Boah; Yi, Gwan-Su

2017-05-31

Recently, the metabolite-likeness of the drug space has emerged and has opened a new possibility for exploring human metabolite-like candidates in drug discovery. However, the applicability of metabolite-likeness in drug discovery has been largely unexplored. Moreover, there are no reports on its applications for the repositioning of drugs to possible enzyme modulators, although enzyme-drug relations could be directly inferred from the similarity relationships between enzyme's metabolites and drugs. We constructed a drug-metabolite structural similarity matrix, which contains 1,861 FDA-approved drugs and 1,110 human intermediary metabolites scored with the Tanimoto similarity. To verify the metabolite-likeness measure for drug repositioning, we analyzed 17 known antimetabolite drugs that resemble the innate metabolites of their eleven target enzymes as the gold standard positives. Highly scored drugs were selected as possible modulators of enzymes for their corresponding metabolites. Then, we assessed the performance of metabolite-likeness with a receiver operating characteristic analysis and compared it with other drug-target prediction methods. We set the similarity threshold for drug repositioning candidates of new enzyme modulators based on maximization of the Youden's index. We also carried out literature surveys for supporting the drug repositioning results based on the metabolite-likeness. In this paper, we applied metabolite-likeness to repurpose FDA-approved drugs to disease-associated enzyme modulators that resemble human innate metabolites. All antimetabolite drugs were mapped with their known 11 target enzymes with statistically significant similarity values to the corresponding metabolites. The comparison with other drug-target prediction methods showed the higher performance of metabolite-likeness for predicting enzyme modulators. After that, the drugs scored higher than similarity score of 0.654 were selected as possible modulators of enzymes for

Design And Evaluation Of Toll Plaza Systems

DOT National Transportation Integrated Search

2001-01-01

This mini-project supported the effort for some preliminary studies of several design issues in the toll plazas of highway systems. Particular attention is paid to the toll plaza on the Garden State Parkway (GST), one of two major toll highways in Ne...

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.

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.

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.

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

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

Chloral hydrate-dependent reduction in the peptidoglycan-induced inflammatory macrophage response is associated with lower expression levels of toll-like receptor 2.

PubMed

Pan, Qingjun; Liu, Yuan; Zhu, Xuezhi; Liu, Huafeng

2014-05-01

The aim of this study was to investigate the effect and mechanism of action of chloral hydrate on the peptidoglycan (PGN)-induced inflammatory macrophage response. The effect of chloral hydrate on the production of tumor necrosis factor α (TNF-α) and interleukin-6 (IL-6) by murine peritoneal macrophages with PGN-stimulation was investigated. In addition, RAW264.7 cells transfected with a nuclear factor-κB (NF-κB) luciferase reporter plasmid stimulated by PGN were used to study the effect of chloral hydrate on the levels NF-κB activity. Flow cytometry and western blotting were performed to investigate the expression levels of toll-like receptor 2 (TLR2) in the treated RAW264.7 cells. It was identified that chloral hydrate reduced the levels of IL-6 and TNF-α produced by the peritoneal macrophages stimulated with PGN. The levels of NF-κB activity of the RAW264.7 cells stimulated by PGN decreased following treatment with chloral hydrate, which was associated with a reduction in the expression levels of TLR2 and reduced levels of TLR2 signal transduction. These data demonstrate that chloral hydrate reduced the magnitude of the PGN-induced inflammatory macrophage response associated with lower expression levels of TLR2.

GLA-SE, a synthetic toll-like receptor 4 agonist, enhances T-cell responses to influenza vaccine in older adults.

PubMed

Behzad, Hayedeh; Huckriede, Anke L W; Haynes, Laura; Gentleman, Beth; Coyle, Krysta; Wilschut, Jan C; Kollmann, Tobias R; Reed, Steven G; McElhaney, Janet E

2012-02-01

The decline in influenza vaccine efficacy in older adults is associated with a limited ability of current split-virus vaccines (SVVs) to stimulate cytotoxic T lymphocyte (CTL) responses required for clinical protection against influenza. The Toll-like receptor 4 agonist glucopyranosyl lipid adjuvant-stable emulsion (GLA-SE) was combined with SVV to stimulate peripheral blood mononuclear cells (PBMCs) in vitro to determine the cytokine response in dendritic cell subsets. Stimulated PBMCs were then challenged with live influenza virus to mimic the response to natural infection following vaccination, using previously identified T-cell correlates of protection. GLA-SE significantly increased the proportion of myeloid dendritic cells that produced tumor necrosis factor α, interleukin 6, and interleukin 12. When combined with SVV to stimulate PBMCs in vitro, this effect of GLA-SE was shown to regulate a T-helper 1 cell response upon challenge with live influenza virus; interleukin 10 production was suppressed, thus significantly increasing the interferon γ to interleukin 10 ratio and the cytolytic (granzyme B) response to influenza virus challenge, both of which have been shown to correlate with protection against influenza in older adults. Our findings suggest that a novel adjuvant, GLA-SE, combined with standard SVV has the potential to significantly improve vaccine-mediated protection against influenza in older adults.

The evaluation model of the design of toll

NASA Astrophysics Data System (ADS)

Feng, Shuting

2018-04-01

In recent years, the dramatic increase in traffic burden has highlighted the necessity of rational allocation of toll plaza. At the same time, the need to consider a lot of factors has enhanced the design requirements. In this background, we carry out research on this subject. We propose a reasonable assumption, and abstract the toll plaza into a model only related to B and L. By using the queuing theory and traffic flow theory, we define the throughput, cost and accident prevent with B and L to acquire the base model. By using the method of linear weighting in economics to calculate this model, the optimal B and L strategies are obtained.

A sustained increase in plasma NEFA upregulates the Toll-like receptor network in human muscle

PubMed Central

Hussey, Sophie E.; Lum, Helen; Alvarez, Andrea; Cipriani, Yolanda; Garduño-Garcia, José de Jesús; Anaya, Luis; Dube, John; Musi, Nicolas

2014-01-01

Aims/hypothesis Insulin-sensitive tissues (muscle, liver) of individuals with obesity and type 2 diabetes mellitus are in a state of low-grade inflammation, characterised by increased Toll-like receptor (TLR) expression and TLR-driven signalling. However, the cause of this mild inflammatory state is unclear. We tested the hypothesis that a prolonged mild increase in plasma NEFA will increase TLR expression and TLR-driven signalling (nuclear factor κB [NFκB] and mitogen-activated kinase [MAPK]) and impair insulin action in muscle of lean healthy individuals. Methods Twelve lean, normal-glucose-tolerant participants were randomised to receive a 48 h infusion (30 ml/h) of saline or Intralipid followed by a euglycaemic–hyperinsulinaemic clamp. Vastus lateralis muscle biopsies were performed before and during the clamp. Results Lipid infusion impaired insulin-stimulated IRS-1 tyrosine phosphorylation and reduced peripheral insulin sensitivity (p < 0.01). The elevation in circulating NEFA increased expression of TLR3, TLR4 and TLR5, and several MAPK (MAPK8, MAP4K4, MAP2K3) and inhibitor of κB kinase-NFκB (CHUK [IKKA], c-REL [REL] and p65 [RELA, NFKB3,p65]) signalling genes (p < 0.05). The lipid infusion also increased extracellular signal-regulated kinase (ERK) phosphorylation (p < 0.05) and tended to reduce the content of nuclear factor of light polypeptide gene enhancer in B cells inhibitor α (p = 0.09). The muscle content of most diacyglycerol, ceramide and acylcarnitine species was unaffected. In summary, insulin resistance induced by prolonged low-dose lipid infusion occurs together with increased TLR-driven inflammatory signalling and impaired insulin-stimulated IRS-1 tyrosine phosphorylation. Conclusions/interpretation A sustained, mild elevation in plasma NEFA is sufficient to increase TLR expression and TLR-driven signalling (NFκB and MAPK) in lean individuals. The activation of this pathway by NEFA may be involved in the pathogenesis of insulin

Differential Alteration in Intestinal Epithelial Cell Expression of Toll-Like Receptor 3 (TLR3) and TLR4 in Inflammatory Bowel Disease

PubMed Central

Cario, Elke; Podolsky, Daniel K.

2000-01-01

Initiation and perpetuation of the inflammatory intestinal responses in inflammatory bowel disease (IBD) may result from an exaggerated host defense reaction of the intestinal epithelium to endogenous lumenal bacterial flora. Intestinal epithelial cell lines constitutively express several functional Toll-like receptors (TLRs) which appear to be key regulators of the innate response system. The aim of this study was to characterize the expression pattern of TLR2, TLR3, TLR4, and TLR5 in primary intestinal epithelial cells from patients with IBD. Small intestinal and colonic biopsy specimens were collected from patients with IBD (Crohn's disease [CD], ulcerative colitis [UC]) and controls. Non-IBD specimens were assessed by immunofluorescence histochemistry using polyclonal antibodies specific for TLR2, TLR3, TLR4, and TLR5. Primary intestinal epithelial cells (IEC) of normal mucosa constitutively expressed TLR3 and TLR5, while TLR2 and TLR4 were only barely detectable. In active IBD, the expression of TLR3 and TLR4 was differentially modulated in the intestinal epithelium. TLR3 was significantly downregulated in IEC in active CD but not in UC. In contrast, TLR4 was strongly upregulated in both UC and CD. TLR2 and TLR5 expression remained unchanged in IBD. These data suggest that IBD may be associated with distinctive changes in selective TLR expression in the intestinal epithelium, implying that alterations in the innate response system may contribute to the pathogenesis of these disorders. PMID:11083826

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

Linagliptin potentiates the effect of l-dopa on the behavioural, biochemical and immunohistochemical changes in experimentally-induced Parkinsonism: Role of toll-like receptor 4, TGF-β1, NF-κB and glucagon-like peptide 1.

PubMed

Kabel, Ahmed M; Omar, Mohamed S; Alhadhrami, A; Alharthi, Salman S; Alrobaian, Majed M

2018-05-01

Our aim was to assess the effect of different doses of linagliptin with or without l-dopa/Carbidopa on 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced parkinsonism in mice. Eighty Balb/c mice were divided into 8 equal groups: Control; MPTP; MPTP + l-dopa/Carbidopa; MPTP + linagliptin 3 mg/kg/day; MPTP + linagliptin 10 mg/kg/day; MPTP + Carboxymethyl cellulose; MPTP + l-dopa/Carbidopa + linagliptin 3 mg/kg/day and MPTP + l-dopa/Carbidopa + linagliptin 10 mg/kg/day. Striatal dopamine, tumor necrosis factor alpha (TNF-α), interleukin 10 (IL-10), transforming growth factor beta 1 (TGF-β1), toll-like receptor 4 (TLR4), antioxidant enzymes, adenosine triphosphate (ATP), glucagon-like peptide-1 (GLP-1), receptors of advanced glycation end products (RAGE), nuclear factor (erythroid-derived 2)-like 2 (Nrf2), heme oxygenase-1 (HO-1), mitochondrial complex I activity, catalepsy and total swim scores were measured. Also, the substantia nigra was subjected to immunohistochemical examination. The combination of l-dopa/Carbidopa and linagliptin in a dose-dependent manner resulted in significant improvement of the behavioural changes, striatal dopamine, antioxidant parameters, Nrf2/HO-1 content, GLP-1, ATP and mitochondrial complex I activity with significant decrease in striatal RAGE, TGF-β1, TNF-α, IL-10, TLR4 and alleviated the immunohistochemical changes better than the groups that received either l-dopa/Carbidopa or linagliptin alone. The combination of l-dopa/Carbidopa and linagliptin might represent a promising therapeutic modality for management of parkinsonism. Copyright © 2018 Elsevier Inc. All rights reserved.

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

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.

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.

47 CFR 63.504 - Contents of applications to close a public toll station where no other such toll station of the...

Code of Federal Regulations, 2010 CFR

2010-10-01

... 47 Telecommunication 3 2010-10-01 2010-10-01 false Contents of applications to close a public toll station where no other such toll station of the applicant in the community will continue service and where telephone toll service is not otherwise available to the public through a telephone exchange connected with the toll lines of a carrier....

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.

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.

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.

Function and Evolution of Vibrato-like Frequency Modulation in Mammals.

PubMed

Charlton, Benjamin D; Taylor, Anna M; Reby, David

2017-09-11

Why do distantly related mammals like sheep, giant pandas, and fur seals produce bleats that are characterized by vibrato-like fundamental frequency (F0) modulation? To answer this question, we used psychoacoustic tests and comparative analyses to investigate whether this distinctive vocal feature has evolved to improve the perception of formants, key acoustic components of animal calls that encode important information about the caller's size and identity [1]. Psychoacoustic tests on humans confirmed that vibrato-like F0 modulation improves the ability of listeners to detect differences in the formant patterns of synthetic bleat-like stimuli. Subsequent phylogenetically controlled comparative analyses revealed that vibrato-like F0 modulation has evolved independently in six mammalian orders in vocal signals with relatively high F0 and, therefore, low spectral density (i.e., less harmonic overtones). We also found that mammals modulate the vibrato in these calls over greater frequency extents when the number of harmonic overtones per formant is low, suggesting that this is a mechanism to improve formant perception in calls with low spectral density. Our findings constitute the first evidence that formant perception in non-speech sounds is improved by fundamental frequency modulation and provide a mechanism for the convergent evolution of bleat-like calls in mammals. They also indicate that selection pressures for animals to transmit important information encoded by formant frequencies (on size and identity, for example) are likely to have been a key driver in the evolution of mammal vocal diversity. Copyright © 2017 Elsevier Ltd. All rights reserved.

Saccharomyces boulardii and Bacillus subtilis B10 modulate TLRs mediated signaling to induce immunity by chicken BMDCs.

PubMed

Rajput, Imran Rashid; Hussain, Altaf; Li, Ya Li; Zhang, Xiaoping; Xu, Xin; Long, Mao Yu; You, Dong Yu; Li, Wei Fen

2014-01-01

Dendritic cells (DCs) are professional antigen-presenting cells (APCs) that play a critical role to activate immune response. They may be targeted for immunomodulation by microbes, including probiotics. In this study, chicken bone marrow dendrite cells (chi-BMDCs) were stimulated with lipopolysachride (LPS), Saccharomyces boulardii (Sb), Bacillus subtilis B10 (Bs), co-culture of Sb + Bs and phosphate buffer saline (PBS) as a control group (Ctr) at 3, 6, and 12 h intervals. Results revealed that treatment groups modulated the phenotype and biological functions of chi-BMDCs. Scan electron microscopy showed attachment of probiotics on the surface of chi-BMDCs. Additionally transmission electron microscopy (TEM) revealed efficiently engulfing and degradation of probiotics. Gene expression levels of MHC-II, CD40, CD80 and CD86 up-regulated in stimulated groups. Furthermore, toll-like receptors TLR1, TLR2, TLR4, and chicken specific TLR15 expressions were improved and downstream associated factors MyD88, TRAF6, TAB1, and NFκ-B mRNA levels increased in all treatment groups as compared to control. Surprisingly, NFκ-B response was noted significant higher in LPS treatment among all groups. Moreover, IL-1β, IL-17, IL-4, TGF-β, and IL-10 production levels were found higher, and lower concentration of INF-γ and IL-8 were observed in Sb, Bs, and Sb + Bs treatment groups. In contrast, LPS groups showed prominent increase in IL-12, INF-γ, and IL-8 concentration levels as compared to control group. Altogether, these results emphasize a potentially important role of Saccharomyces boulardii and Bacillus subtilis B10 in modulating immunological functions of chi-BMDCs by targeting specific toll like receptors (TLRs) and associated factors. The role of probiotics on chi-BMDCs functionality in a non-mammalian species have been presented for the first time. © 2013 Wiley Periodicals, Inc.

The design of a toll plaza

NASA Astrophysics Data System (ADS)

Dong, Haibin

2017-04-01

In this paper, a model is established to find the optimal shape, size and merging pattern of the toll plaza. The main work is how to take the aspects such as the accident prevention, throughput and cost into consideration to make the model of the toll plaza optimal. By analyzing the match of the number of tollbooths (B) and travel lanes (L) considering safety and cost, the optimal toll plaza model is established when the traffic flow is given.

Modulation of cardiac fibrosis by Krüppel-like factor 6 through transcriptional control of thrombospondin 4 in cardiomyocytes

PubMed Central

Sawaki, Daigo; Hou, Lianguo; Tomida, Shota; Sun, Junqing; Zhan, Hong; Aizawa, Kenichi; Son, Bo-Kyung; Kariya, Taro; Takimoto, Eiki; Otsu, Kinya; Conway, Simon J.; Manabe, Ichiro; Komuro, Issei; Friedman, Scott L.; Nagai, Ryozo; Suzuki, Toru

2015-01-01

Aims Krüppel-like factors (KLFs) are a family of transcription factors which play important roles in the heart under pathological and developmental conditions. We previously identified and cloned Klf6 whose homozygous mutation in mice results in embryonic lethality suggesting a role in cardiovascular development. Effects of KLF6 on pathological regulation of the heart were investigated in the present study. Methods and results Mice heterozygous for Klf6 resulted in significantly diminished levels of cardiac fibrosis in response to angiotensin II infusion. Intriguingly, a similar phenotype was seen in cardiomyocyte-specific Klf6 knockout mice, but not in cardiac fibroblast-specific knockout mice. Microarray analysis revealed increased levels of the extracellular matrix factor, thrombospondin 4 (TSP4), in the Klf6-ablated heart. Mechanistically, KLF6 directly suppressed Tsp4 expression levels, and cardiac TSP4 regulated the activation of cardiac fibroblasts to regulate cardiac fibrosis. Conclusion Our present studies on the cardiac function of KLF6 show a new mechanism whereby cardiomyocytes regulate cardiac fibrosis through transcriptional control of the extracellular matrix factor, TSP4, which, in turn, modulates activation of cardiac fibroblasts. PMID:25987545

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

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

33 CFR 402.11 - Schedule of tolls.

Code of Federal Regulations, 2014 CFR

2014-07-01

... TRANSPORTATION TARIFF OF TOLLS § 402.11 Schedule of tolls. Item Column 1 Description of charges Column 2 Rate ($)Montreal to or from Lake Ontario (5 locks) Column 3 Rate ($)Welland Canal—Lake Ontario to or from Lake Erie (8 locks) 1 Subject to item 3, for complete transit of the Seaway, a composite toll, comprising: (1...

33 CFR 402.10 - Schedule of tolls.

Code of Federal Regulations, 2013 CFR

2013-07-01

... TRANSPORTATION TARIFF OF TOLLS § 402.10 Schedule of tolls. Item Column 1 Description of Charges Column 2 Rate ($) Montreal to or from Lake Ontario (5 locks) Column 3 Rate ($) Welland Canal—Lake Ontario to or from Lake Erie (8 locks) 1. Subject to item 3, for complete transit of the Seaway, a composite toll, comprising...

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

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.

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

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.

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

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.

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.

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.

Macrophage ABCA1 reduces MyD88-dependent Toll-like receptor trafficking to lipid rafts by reduction of lipid raft cholesterol[S

PubMed Central

Zhu, Xuewei; Owen, John S.; Wilson, Martha D.; Li, Haitao; Griffiths, Gary L.; Thomas, Michael J.; Hiltbold, Elizabeth M.; Fessler, Michael B.; Parks, John S.

2010-01-01

We previously showed that macrophages from macrophage-specific ATP-binding cassette transporter A1 (ABCA1) knockout (Abca1-M/-M) mice had an enhanced proinflammatory response to the Toll-like receptor (TLR) 4 agonist, lipopolysaccharide (LPS), compared with wild-type (WT) mice. In the present study, we demonstrate a direct association between free cholesterol (FC), lipid raft content, and hyper-responsiveness of macrophages to LPS in WT mice. Abca1-M/-M macrophages were also hyper-responsive to specific agonists to TLR2, TLR7, and TLR9, but not TLR3, compared with WT macrophages. We hypothesized that ABCA1 regulates macrophage responsiveness to TLR agonists by modulation of lipid raft cholesterol and TLR mobilization to lipid rafts. We demonstrated that Abca1-M/-M vs. WT macrophages contained 23% more FC in isolated lipid rafts. Further, mass spectrometric analysis suggested raft phospholipid composition was unchanged. Although cell surface expression of TLR4 was similar between Abca1-M/-M and WT macrophages, significantly more TLR4 was distributed in membrane lipid rafts in Abca1-M/-M macrophages. Abca1-M/-M macrophages also exhibited increased trafficking of the predominantly intracellular TLR9 into lipid rafts in response to TLR9-specific agonist (CpG). Collectively, our data suggest that macrophage ABCA1 dampens inflammation by reducing MyD88-dependent TLRs trafficking to lipid rafts by selective reduction of FC content in lipid rafts. PMID:20650929

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

47 CFR 42.6 - Retention of telephone toll records.

Code of Federal Regulations, 2010 CFR

2010-10-01

... telephone toll calls: the name, address, and telephone number of the caller, telephone number called, date, time and length of the call. Each carrier shall retain this information for toll calls that it bills whether it is billing its own toll service customers for toll calls or billing customers for another...

Up-regulation of Toll-like receptor 4/nuclear factor-kappaB signaling is associated with enhanced adipogenesis and insulin resistance in fetal skeletal muscle of obese sheep at late gestation.

PubMed

Yan, Xu; Zhu, Mei J; Xu, Wei; Tong, Jun F; Ford, Stephen P; Nathanielsz, Peter W; Du, Min

2010-01-01

Maternal obesity is increasing at an alarming rate. We previously showed that maternal obesity induces an inflammatory response and enhances adipogenesis in fetal skeletal muscle at midgestation. The objective of this study was to evaluate effects of maternal obesity on adipogenesis, inflammatory signaling, and insulin pathways at late gestation when ovine fetal skeletal muscle matures. Nonpregnant ewes were assigned to a control diet (Con, fed 100% of National Research Council nutrient recommendations, n = 6) or obesogenic diet (OB, fed 150% of National Research Council recommendations, n = 6) from 60 d before to 135 d after conception (term 148 d) when the fetal semitendenosus skeletal muscle was sampled. Expression of the adipogenic marker, peroxisome proliferator-activated receptor-gamma, was increased in OB compared with Con fetal semitendenosus muscle, indicating up-regulation of adipogenesis. More intramuscular adipocytes were observed in OB muscle. Phosphorylation of inhibitor-kappaB kinase-alpha/beta and nuclear factor-kappaB RelA/p65 were both increased in OB fetal muscle, indicating activation of nuclear factor-kappaB pathway. Phosphorylation of c-Jun N-terminal kinase and c-Jun (at Ser 63 and Ser 73) was also elevated. Toll-like receptor 4 expression was higher in OB than Con fetal muscle. Moreover, despite higher insulin concentrations in OB vs. Con fetal plasma (2.89 +/- 0.53 vs. 1.06 +/- 0.52 ng/ml; P < 0.05), phosphorylation of protein kinase B at Ser 473 was reduced, indicating insulin resistance. In conclusion, our data show maternal obesity-induced inflammatory signaling in late gestation fetal muscle, which correlates with increased im adipogenesis and insulin resistance, which may predispose offspring to later-life obesity and diabetes.

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.

Technology scan for electronic toll collection.

DOT National Transportation Integrated Search

2008-06-01

The purpose of this project was to identify and assess available technologies and methodologies for electronic toll collection (ETC) and to develop recommendations for the best way(s) to implement toll collection in the Louisville metropolitan area. ...

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

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

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.

Sustained activation of toll-like receptor 9 induces an invasive phenotype in lung fibroblasts: possible implications in idiopathic pulmonary fibrosis.

PubMed

Kirillov, Varvara; Siler, Jonathan T; Ramadass, Mahalakshmi; Ge, Lingyin; Davis, James; Grant, Geraldine; Nathan, Steven D; Jarai, Gabor; Trujillo, Glenda

2015-04-01

Idiopathic pulmonary fibrosis (IPF) is characterized by excessive scarring of the lung parenchyma, resulting in a steady decline of lung function and ultimately respiratory failure. The disease course of IPF is extremely variable, with some patients exhibiting stability of symptoms for prolonged periods of time, whereas others exhibit rapid progression and loss of lung function. Viral infections have been implicated in IPF and linked to disease severity; however, whether they directly contribute to progression is unclear. We previously classified patients as rapid and slow progressors on the basis of clinical features and expression of the pathogen recognition receptor, Toll-like receptor 9 (TLR9). Activation of TLR9 in vivo exacerbated IPF in mice and induced differentiation of myofibroblasts in vitro, but the mechanism of TLR9 up-regulation and progression of fibrosis are unknown. Herein, we investigate whether transforming growth factor (TGF)-β, a pleiotropic cytokine central to IPF pathogenesis, regulates TLR9 in lung myofibroblasts. Results showed induction of TLR9 expression by TGF-β in lung myofibroblasts and a distinct profibrotic myofibroblast phenotype driven by stimulation with the TLR9 agonist, CpG-DNA. Chronic TLR9 stimulation resulted in stably differentiated α-smooth muscle actin(+)/platelet-derived growth factor receptor α(+)/CD44(+)/matrix metalloproteinase-14(+)/matrix metalloproteinase-2(+) myofibroblasts, which secrete inflammatory cytokines, invade Matrigel toward platelet-derived growth factor, and resist hypoxia-induced apoptosis. These results suggest a mechanism by which TGF-β and TLR9 responses in myofibroblasts collaborate to drive rapid progression of IPF. Copyright © 2015 American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved.

Sarcoid-like lesions in Paracoccidioidomycosis: immunological factors*

PubMed Central

de Medeiros, Vanessa Lucília Silveira; Arruda, Lúcia

2013-01-01

The clinical presentation of paracoccidioidomycosis is spectral. Spontaneous cure, state of latency or active disease with different levels of severity can occur after the hematogenous dissemination. The morphology and number of skin lesions will depend on the interaction of host immunity, which is specific and individual, and fungus virulence. Some individuals have natural good immunity, which added to the low virulence of the fungus maintain the presence of well-marked granulomas with no microorganism and negative serology for a long time, making the diagnosis a challenge. Factors inherent to the fungus, however, may modulate the immune response and modify the clinical picture over the time. We present a sarcoidosis-like clinical presentation and discuss the immunological factors involved. PMID:23539015

78 FR 19105 - Tariff of Tolls

Federal Register 2010, 2011, 2012, 2013, 2014

2013-03-29

... revised to read as follows: Sec. 402.10 Schedule of tolls. Column 1 Column 2 Column 3 Rate ($) Welland... Lake Erie (8 (5 locks) locks) 1 Subject to item 3, for complete transit of the Seaway, a composite toll...

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.

GLA-SE, a Synthetic Toll-like Receptor 4 Agonist, Enhances T-Cell Responses to Influenza Vaccine in Older Adults

PubMed Central

Behzad, Hayedeh; Huckriede, Anke L. W.; Haynes, Laura; Gentleman, Beth; Coyle, Krysta; Wilschut, Jan C.; Kollmann, Tobias R.; Reed, Steven G.

2012-01-01

Background. The decline in influenza vaccine efficacy in older adults is associated with a limited ability of current split-virus vaccines (SVVs) to stimulate cytotoxic T lymphocyte (CTL) responses required for clinical protection against influenza. Methods. The Toll-like receptor 4 agonist glucopyranosyl lipid adjuvant–stable emulsion (GLA-SE) was combined with SVV to stimulate peripheral blood mononuclear cells (PBMCs) in vitro to determine the cytokine response in dendritic cell subsets. Stimulated PBMCs were then challenged with live influenza virus to mimic the response to natural infection following vaccination, using previously identified T-cell correlates of protection. Results. GLA-SE significantly increased the proportion of myeloid dendritic cells that produced tumor necrosis factor α, interleukin 6, and interleukin 12. When combined with SVV to stimulate PBMCs in vitro, this effect of GLA-SE was shown to regulate a T-helper 1 cell response upon challenge with live influenza virus; interleukin 10 production was suppressed, thus significantly increasing the interferon γ to interleukin 10 ratio and the cytolytic (granzyme B) response to influenza virus challenge, both of which have been shown to correlate with protection against influenza in older adults. Conclusions. Our findings suggest that a novel adjuvant, GLA-SE, combined with standard SVV has the potential to significantly improve vaccine-mediated protection against influenza in older adults. PMID:22147791

Toll-like receptor 2 deficiency increases resistance to Pseudomonas aeruginosa pneumonia in the setting of sepsis-induced immune dysfunction.

PubMed

Pène, Frédéric; Grimaldi, David; Zuber, Benjamin; Sauneuf, Bertrand; Rousseau, Christophe; El Hachem, Carole; Martin, Clémence; Belaïdouni, Nadia; Balloy, Viviane; Mira, Jean-Paul; Chiche, Jean-Daniel

2012-09-15

Sepsis is characterized by a dysregulated inflammatory response followed by immunosuppression that favors the development of secondary infections. Toll-like receptors (TLRs) are major regulators of the host's response to infections. How variability in TLR signaling may impact the development of sepsis-induced immune dysfunction has not been established. We sought to establish the role of TLR2, TLR4, and TLR5 in postseptic mice with Pseudomonas aeruginosa pneumonia. We used an experimental model of sublethal polymicrobial sepsis induced by cecal ligation and puncture (CLP). Wild-type, tlr2(-/-), tlr4(-/-), tlr5(-/-), tlr2 4(-/-) mice that underwent CLP were secondarily subjected to P. aeruginosa pulmonary infection. Postseptic wild-type and tlr4(-/-) and tlr5(-/-) mice displayed high susceptibility to P. aeruginosa pneumonia. In contrast, TLR2-deficient mice, either tlr2(-/-)or tlr2 4(-/-), that underwent CLP were resistant to the secondary pulmonary infection. As compared to wild-type mice, tlr2(-/-) mice displayed improvement in bacterial clearance, decreased bacteremic dissemination, and attenuated lung damage. Furthermore, tlr2(-/-) mice exhibited a pulmonary proinflammatory cytokine balance, with increased production of tumor necrosis factor α and decreased release of interleukin 10. In a model of secondary P. aeruginosa pneumonia in postseptic mice, TLR2 deficiency improves survival by promoting efficient bacterial clearance and restoring a proinflammatory cytokine balance in the lung.

Soy-Leaf Extract Exerts Atheroprotective Effects via Modulation of Krüppel-Like Factor 2 and Adhesion Molecules

PubMed Central

Han, Jong-Min; Li, Hua; Cho, Moon-Hee; Baek, Seung-Hwa; Lee, Chul-Ho; Park, Ho-Yong; Jeong, Tae-Sook

2017-01-01

Soy-leaf extracts exert their cardioprotective effects by inducing endothelium-dependent vasodilation in the arteries, and they favorably modulate the serum lipid profile. In this study, we investigated the atheroprotective effects of an ethanol extract of soy leaf (ESL) in human umbilical vein endothelial cells (HUVECs) and high-cholesterol diet (HCD)-fed low-density lipoprotein receptor deficient (LDLR−/−) mice. ESL induced the expression of Krüppel-like factor 2 (KLF2), an endothelial transcription factor, and endothelial nitric oxide synthase (eNOS), and suppressed the expression of vascular cell adhesion molecule-1 (VCAM-1) and intercellular adhesion molecule-1 (ICAM-1) through moderate inflammatory signal activation, not only in tumor necrosis factor-α (TNF-α)-stimulated HUVECs but also in 7-ketocholesterol (7-KC)-stimulated HUVECs. ESL supplementation reduced aortic lesion formation in Western diet-fed LDLR−/− mice by 46% (p < 0.01) compared to the HCD group. ESL also markedly decreased the aortic expression levels of VCAM-1, ICAM-1, monocyte chemotactic protein-1 (MCP-1), TNF-α, IL-6, IL-1β, matrix metallopeptidase 9 (MMP-9), and fractalkine, while the expression of KLF2 was significantly increased. These results suggest that ESL supplementation has potential for preventing HCD-induced atherosclerosis effectively. PMID:28208647

Role of the Toll-like receptor pathway in the recognition of orthopedic implant wear-debris particles.

PubMed

Pearl, Jeremy I; Ma, Ting; Irani, Afraaz R; Huang, Zhinong; Robinson, William H; Smith, Robert L; Goodman, Stuart B

2011-08-01

The inflammatory response to prosthetic implant-derived wear particles is the primary cause of bone loss and aseptic loosening of implants, but the mechanisms by which macrophages recognize and respond to particles remain unknown. Studies of innate immunity demonstrate that Toll-like receptors (TLRs) recognize pathogen-associated molecular patterns (PAMPs) and danger-associated molecular patterns (DAMPS). All TLRs signal through myeloid differentiation factor 88 (MyD88), except TLR3 which signals through TIR domain containing adapter inducing interferon-beta (TRIF), and TLR4 which signals through both MyD88 and TRIF. We hypothesized that wear-debris particles may act as PAMPs/DAMPs and activate macrophages via TLRs. To test this hypothesis, we first demonstrated that inhibition of MyD88 decreases polymethylmethacrylate (PMMA) particle-induced production of TNF-α in RAW 264.7 macrophages. Next we compared particle-induced production of TNF-α among MyD88 knockout (MyD88(-/-)), TRIF knockout (TRIF(-/-)), and wild type (WT) murine macrophages. Relative to WT, disruption of MyD88 signaling diminished, and disruption of TRIF amplified the particle-induced production of TNF-α. Gene expression data indicated that this latter increase in TNF-α was due to a compensatory increase in expression of MyD88 associated components of the TLR pathway. Finally, using an in vivo model, MyD88(-/-) mice developed less particle-induced osteolysis than WT mice. These results indicate that the response to PMMA particles is partly dependent on MyD88, presumably as part of TLR signaling; MyD88 may represent a therapeutic target for prevention of wear debris-induced periprosthetic osteolysis. Copyright © 2011 Elsevier Ltd. All rights reserved.

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.

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.

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

Lysosomal trafficking regulator Lyst links membrane trafficking to toll-like receptor–mediated inflammatory responses

PubMed Central

Krautkrämer, Martina

2017-01-01

Subcellular compartmentalization of receptor signaling is an emerging principle in innate immunity. However, the functional integration of receptor signaling pathways into membrane trafficking routes and its physiological relevance for immune responses is still largely unclear. In this study, using Lyst-mutant beige mice, we show that lysosomal trafficking regulator Lyst links endolysosomal organization to the selective control of toll-like receptor 3 (TLR3)– and TLR4-mediated proinflammatory responses. Consequently, Lyst-mutant mice showed increased susceptibility to bacterial infection and were largely resistant to endotoxin-induced septic shock. Mechanistic analysis revealed that Lyst specifically controls TLR3- and TLR4-induced endosomal TRIF (TIR domain–containing adapter-inducing interferon β) signaling pathways. Loss of functional Lyst leads to dysregulated phagosomal maturation, resulting in a failure to form an activation-induced Rab7+ endosomal/phagosomal compartment. This specific Rab7+ compartment was further demonstrated to serve as a major site for active TRIF signaling events, thus linking phagosomal maturation to specific TLR signaling pathways. The immunoregulatory role of Lyst on TLR signaling pathways was confirmed in human cells by CRISPR/Cas9-mediated gene inactivation. As mutations in LYST cause human Chédiak-Higashi syndrome, a severe immunodeficiency, our findings also contribute to a better understanding of human disease mechanisms. PMID:27881733

Association of single nucleotide polymorphisms in pro-inflammatory cytokine and toll-like receptor genes with pediatric hematogenous osteomyelitis.

PubMed

Osman, A E; Mubasher, M; ElSheikh, N E; AlHarthi, H; AlZahrani, M S; Ahmed, N; ElGhazali, G; Bradley, B A; Fadil, A-S A

2016-05-23

Hematogenous osteomyelitis (HO) is a bone infection wherein bacteria penetrate to the bone through the blood stream. Several single nucleotide polymorphisms (SNPs) have been associated with susceptibility to infectious diseases. In this study, we investigated the contribution of SNPs in interleukin (IL)-1B1 (rs16944), IL1A (rs1800587), IL1B (rs1143634), toll-like receptor (TLR)-2 (rs3804099), TLR4 (rs4986790), TLR4 (rs4986791), IL1R (rs2234650), tumor necrosis factor (TNF)-α (rs1800629), TNF (rs361525), and IL1RN (rs315952) towards the development of HO in Saudi patients and compared to healthy controls. Fifty-two patients diagnosed with HO and 103 healthy individuals were genotyped. The frequencies of genotypes GG (rs16944) and AA (rs16944) were lower and higher in patients [odds ratio (OR) = 0.34, Pc = 0.05] and controls (OR = 1.33, Pc = 0.05), respectively, suggesting that SNPs at this locus could alter HO susceptibility. In addition, the patients and controls exhibited lower and higher frequencies of the alleles G (rs16944) (OR = 0.43, Pc = 0.007) and A (rs16944) (OR = 2.32, Pc = 0.007), respectively. The expression of alleles C (rs3804099) and T (rs3804099) were higher in patients (OR = 2.05, Pc = 0.04) and controls (OR = 0.49, Pc = 0.04), respectively. In conclusion, SNPs at rs16944 and rs3804099 were found to be associated with HO in the Saudi population.

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.

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.

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.

Butyrate modulating effects on pro-inflammatory pathways in human intestinal epithelial cells.

PubMed

Elce, A; Amato, F; Zarrilli, F; Calignano, A; Troncone, R; Castaldo, G; Canani, R B

2017-10-13

Butyrate acts as energy source for intestinal epithelial cells and as key mediator of several immune processes, modulating gene expression mainly through histone deacetylation inhibition. Thanks to these effects, butyrate has been proposed for the treatment of many intestinal diseases. Aim of this study was to investigate the effect of butyrate on the expression of a large series of target genes encoding proteins involved in pro-inflammatory pathways. We performed quantitative real-time-PCR analysis of the expression of 86 genes encoding proteins bearing to pro-inflammatory pathways, before and after butyrate exposure, in primary epithelial cells derived from human small intestine and colon. Butyrate significantly down-regulated the expression of genes involved in inflammatory response, among which nuclear factor kappa beta, interferon-gamma, Toll like 2 receptor and tumour necrosis factor-alpha. Further confirmations of these data, including studies at protein level, would support the use of butyrate as effective therapeutic strategy in intestinal inflammatory disorders.

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

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

Toll-like receptor 3 pre-conditioning increases the therapeutic efficacy of umbilical cord mesenchymal stromal cells in a dextran sulfate sodium-induced colitis model.

PubMed

Fuenzalida, Patricia; Kurte, Mónica; Fernández-O'ryan, Catalina; Ibañez, Cristina; Gauthier-Abeliuk, Melanie; Vega-Letter, Ana María; Gonzalez, Paz; Irarrázabal, Carlos; Quezada, Nataly; Figueroa, Fernando; Carrión, Flavio

2016-05-01

Immunomodulatory properties of human umbilical cord-derived mesenchymal stromal cells (UCMSCs) can be differentially modulated by toll-like receptors (TLR) agonists. Here, the therapeutic efficacy of short TLR3 and TLR4 pre-conditioning of UCMSCs was evaluated in a dextran sulfate sodium (DSS)-induced colitis in mice. The novelty of this study is that although modulation of human MSCs activity by TLRs is not a new concept, this is the first time that short TLR pre-conditioning has been carried out in a murine inflammatory model of acute colitis. C57BL/6 mice were exposed to 2.5% dextran sulfate sodium (DSS) in drinking water ad libitum for 7 days. At days 1 and 3, mice were injected intraperitoneally with 1 × 10(6) UCMSCs untreated or TLR3 and TLR4 pre-conditioned UCMSCs. UCMSCs were pre-conditioned with poly(I:C) for TLR3 and LPS for TLR4 for 1 h at 37°C and 5% CO2. We evaluated clinical signs of disease and body weights daily. At the end of the experiment, colon length and histological changes were assessed. poly(I:C) pre-conditioned UCMSCs significantly ameliorated the clinical and histopathological severity of DSS-induced colitis compared with UCMSCs or LPS pre-conditioned UCMSCs. In contrast, infusion of LPS pre-conditioned UCMSCs significantly increased clinical signs of disease, colon shortening and histological disease index in DSS-induced colitis. These results show that short in vitro TLR3 pre-conditioning with poly(I:C) enhances the therapeutic efficacy of UCMSCs, which is a major breakthrough for developing improved treatments to patients with inflammatory bowel disease. Copyright © 2016 International Society for Cellular Therapy. Published by Elsevier Inc. All rights reserved.

40 CFR 52.111 - Toll free number assignment.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 3 2013-07-01 2013-07-01 false Toll free number assignment. 52.111... (CONTINUED) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS Arizona § 52.111 Toll free number assignment. Toll free numbers shall be made available on a first-come, first-served basis unless otherwise directed...

40 CFR 52.111 - Toll free number assignment.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 3 2010-07-01 2010-07-01 false Toll free number assignment. 52.111... (CONTINUED) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS Arizona § 52.111 Toll free number assignment. Toll free numbers shall be made available on a first-come, first-served basis unless otherwise directed...

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.

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.

Propofol Attenuates Airway Inflammation in a Mast Cell-Dependent Mouse Model of Allergic Asthma by Inhibiting the Toll-like Receptor 4/Reactive Oxygen Species/Nuclear Factor κB Signaling Pathway.

PubMed

Li, Hong-Yi; Meng, Jing-Xia; Liu, Zhen; Liu, Xiao-Wen; Huang, Yu-Guang; Zhao, Jing

2018-06-01

Propofol, an intravenous anesthetic agent widely used in clinical practice, is the preferred anesthetic for asthmatic patients. This study was designed to determine the protective effect and underlying mechanisms of propofol on airway inflammation in a mast cell-dependent mouse model of allergic asthma. Mice were sensitized by ovalbumin (OVA) without alum and challenged with OVA three times. Propofol was given intraperitoneally 0.5 h prior to OVA challenge. The inflammatory cell count and production of cytokines in the bronchoalveolar lavage fluid (BALF) were detected. The changes of lung histology and key molecules of the toll-like receptor 4 (TLR4)/reactive oxygen species (ROS)/NF-κB signaling pathway were also measured. The results showed that propofol significantly decreased the number of eosinophils and the levels of IL-4, IL-5, IL-6, IL-13, and TNF-α in BALF. Furthermore, propofol significantly attenuated airway inflammation, as characterized by fewer infiltrating inflammatory cells and decreased mucus production and goblet cell hyperplasia. Meanwhile, the expression of TLR4, and its downstream signaling adaptor molecules--myeloid differentiation factor 88 (MyD88) and NF-κB, were inhibited by propofol. The hydrogen peroxide and methane dicarboxylic aldehyde levels were decreased by propofol, and the superoxide dismutase activity was increased in propofol treatment group. These findings indicate that propofol may attenuate airway inflammation by inhibiting the TLR4/MyD88/ROS/NF-κB signaling pathway in a mast cell-dependent mouse model of allergic asthma.

Krüppel-like Factor 3 (KLF3/BKLF) Is Required for Widespread Repression of the Inflammatory Modulator Galectin-3 (Lgals3)*

PubMed Central

Knights, Alexander J.; Yik, Jinfen J.; Mat Jusoh, Hanapi; Norton, Laura J.; Funnell, Alister P. W.; Pearson, Richard C. M.; Bell-Anderson, Kim S.; Crossley, Merlin; Quinlan, Kate G. R.

2016-01-01

The Lgals3 gene encodes a multifunctional β-galactoside-binding protein, galectin-3. Galectin-3 has been implicated in a broad range of biological processes from chemotaxis and inflammation to fibrosis and apoptosis. The role of galectin-3 as a modulator of inflammation has been studied intensively, and recent evidence suggests that it may serve as a protective factor in obesity and other metabolic disorders. Despite considerable interest in galectin-3, little is known about its physiological regulation at the transcriptional level. Here, using knockout mice, chromatin immunoprecipitations, and cellular and molecular analyses, we show that the zinc finger transcription factor Krüppel-like factor 3 (KLF3) directly represses galectin-3 transcription. We find that galectin-3 is broadly up-regulated in KLF3-deficient mouse tissues, that KLF3 occupies regulatory regions of the Lgals3 gene, and that KLF3 directly binds its cognate elements (CACCC boxes) in the galectin-3 promoter and represses its activation in cellular assays. We also provide mechanistic insights into the regulation of Lgals3, demonstrating that C-terminal binding protein (CtBP) is required to drive optimal KLF3-mediated silencing. These findings help to enhance our understanding of how expression of the inflammatory modulator galectin-3 is controlled, opening up avenues for potential therapeutic interventions in the future. PMID:27226561

Role of toll-like receptor 4 Asp299Gly polymorphism in the development of cardiovascular diseases in HIV-infected patients.

PubMed

Tarancon-Diez, Laura; De Pablo-Bernal, Rebeca S; Jiménez, José L; Álvarez-Ríos, Ana I; Genebat, Miguel; Rosado-Sánchez, Isaac; Muñoz-Fernández, María-Ángeles; Ruiz-Mateos, Ezequiel; Leal, Manuel

2018-05-15

Cardiovascular diseases (CVDs) are one of the main causes of morbimortality in HIV-infected patients on suppressive antiretroviral therapy. The objective of this work was to evaluate the role of single nucleotide polymorphisms (SNPs) in lipopolysaccharide (LPS) Toll-like receptor 4 (TLR4) and CVDs occurrence in HIV-infected patients. Additionally, the functional consequences of carrying these SNPs were analyzed. The association of TLR4 SNPs, Asp299Gly/Thr399Ile with CVDs occurrence was analyzed using multivariate logistic regression models. Clinical, immunological, and traditional cardiovascular risk factors were used as covariates. The monocyte phenotype and response were assessed by multiparametric flow cytometry comparing carriers with noncarriers of this SNP. Asp299Gly SNP, assayed in 253 HIV-infected patients, was independently associated with the occurrence of CVDs after adjusting for CD4 T-cell nadir, HCV-coinfection, bacterial pneumonia, diabetes mellitus, and traditional cardiovascular risk factors [odds ratio (confidence interval 95%) = 3.672 (1.061-12.712), P = 0.04). Carriers of Asp299Gly SNP showed higher percentage of patrolling and intermediate monocytes producing a proinflammatory combination of cytokines compared with noncarriers (P = 0.037 and P = 0.046, respectively). Intermediate monocyte subset levels correlated with soluble interleukin-6 levels only in carriers (r = 0.89; P = 0.01). TLR4 Asp299Gly polymorphism is independently associated with the occurrence of CVDs in HIV-infected patients. The proinflammatory profile associated to this variant could be involved in the development of atherosclerotic pathologies.

23 CFR 950.5 - Requirement to use electronic toll collection technology.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 23 Highways 1 2010-04-01 2010-04-01 false Requirement to use electronic toll collection technology... technology. (a) Any toll agency operating a toll facility pursuant to authority under a 1604 toll program... agency using electronic toll collection technology must develop and implement reasonable methods to...

23 CFR 950.5 - Requirement to use electronic toll collection technology.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 23 Highways 1 2011-04-01 2011-04-01 false Requirement to use electronic toll collection technology... technology. (a) Any toll agency operating a toll facility pursuant to authority under a 1604 toll program... agency using electronic toll collection technology must develop and implement reasonable methods to...

23 CFR 950.5 - Requirement to use electronic toll collection technology.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 23 Highways 1 2013-04-01 2013-04-01 false Requirement to use electronic toll collection technology... technology. (a) Any toll agency operating a toll facility pursuant to authority under a 1604 toll program... agency using electronic toll collection technology must develop and implement reasonable methods to...

23 CFR 950.5 - Requirement to use electronic toll collection technology.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 23 Highways 1 2014-04-01 2014-04-01 false Requirement to use electronic toll collection technology... technology. (a) Any toll agency operating a toll facility pursuant to authority under a 1604 toll program... agency using electronic toll collection technology must develop and implement reasonable methods to...

23 CFR 950.5 - Requirement to use electronic toll collection technology.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 23 Highways 1 2012-04-01 2012-04-01 false Requirement to use electronic toll collection technology... technology. (a) Any toll agency operating a toll facility pursuant to authority under a 1604 toll program... agency using electronic toll collection technology must develop and implement reasonable methods to...

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.

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.

Toll pathway is required for wound-induced expression of barrier repair genes in the Drosophila epidermis

PubMed Central

Capilla, Amalia; Karachentsev, Dmitry; Patterson, Rachel A.; Hermann, Anita; Juarez, Michelle T.; McGinnis, William

2017-01-01

The epidermis serves as a protective barrier in animals. After epidermal injury, barrier repair requires activation of many wound response genes in epidermal cells surrounding wound sites. Two such genes in Drosophila encode the enzymes dopa decarboxylase (Ddc) and tyrosine hydroxylase (ple). In this paper we explore the involvement of the Toll/NF-κB pathway in the localized activation of wound repair genes around epidermal breaks. Robust activation of wound-induced transcription from ple and Ddc requires Toll pathway components ranging from the extracellular ligand Spätzle to the Dif transcription factor. Epistasis experiments indicate a requirement for Spätzle ligand downstream of hydrogen peroxide and protease function, both of which are known activators of wound-induced transcription. The localized activation of Toll a few cell diameters from wound edges is reminiscent of local activation of Toll in early embryonic ventral hypoderm, consistent with the hypothesis that the dorsal–ventral patterning function of Toll arose from the evolutionary cooption of a morphogen-responsive function in wound repair. Furthermore, the combinatorial activity of Toll and other signaling pathways in activating epidermal barrier repair genes can help explain why developmental activation of the Toll, ERK, or JNK pathways alone fail to activate wound repair loci. PMID:28289197

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

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.

Type of Inflammation Differentially Affects Expression of Interleukin 1β and 6, Tumor Necrosis Factor-α and Toll-Like Receptors in Subclinical Endometritis in Mares

PubMed Central

Szóstek, Anna Z.; Gajos, Katarzyna; Kozdrowski, Roland; Nowak, Marcin; Okuda, Kiyoshi

2016-01-01

Mares that fail to conceive or lose their embryos, without showing typical signs of clinical endometritis, should be suspected of subclinical endometritis (SE). In this study, the question was addressed: does SE fully activate selected mechanisms of innate immunity in mares? For this aim, expression of mRNAs for Toll-like Receptor 2 and 4 (TLR 2/4), interleukin 1β (IL-1β), interleukin 6 (IL-6) and tumor necrosis factor α (TNF) was examined in control mares versus either mares suffering from chronic endometritis (ChE) or subacute suppurative endometritis (SSE). The concentrations of IL-1β, IL-6 and TNF-α in supernatants from endometrial tissue cultures after 4 h incubation were measured using the enzyme immunoassay (EIA) method. Eighty-two warmblood mares, of known breeding history, were enrolled in this study. Based on histopathological assessment, mares were classified as suffering from ChE, SSE or as being healthy. In addition, immuno-localization of both TLR2 and TLR4 as well as TNF-α was investigated in the equine endometria. The mRNA expression of TLR2 (P < 0.01), IL-1β (P < 0.0001), IL-6 (P < 0.0001) and TLR4 and TNF (P < 0.05) was up-regulated in endometria of mares suffering from SSE compared with unaffected mares. Concentrations of IL-6 and TNF-α were increased only in mares exhibiting SSE, compared with unaffected (P < 0.01 for both) and ChE mares (P < 0.05 for both). Immuno-localization of TNF-α and TLRs was confirmed, both in unaffected and SE-affected endometria, and was present in the luminal and glandular epithelia and stromal cells. The severity of inflammation impacts the immune response and fosters activation of innate immunity mechanisms, as observed in the endometria of mares. The intracellular localization of TLRs and TNF-α in the endometria indicates a key role of endometrial epithelial and stromal cells in the immune response and inflammation. PMID:27152525

Serpin Facilitates Tumor-Suppressive Cell Competition by Blocking Toll-Mediated Yki Activation in Drosophila.

PubMed

Katsukawa, Mitsuko; Ohsawa, Shizue; Zhang, Lina; Yan, Yan; Igaki, Tatsushi

2018-06-04

Normal epithelial tissue exerts an intrinsic tumor-suppressive effect against oncogenically transformed cells. In Drosophila imaginal epithelium, clones of oncogenic polarity-deficient cells mutant for scribble (scrib) or discs large (dlg) are eliminated by cell competition when surrounded by wild-type cells. Here, through a genetic screen in Drosophila, we identify Serpin5 (Spn5), a secreted negative regulator of Toll signaling, as a crucial factor for epithelial cells to eliminate scrib mutant clones from epithelium. Downregulation of Spn5 in wild-type cells leads to elevation of Toll signaling in neighboring scrib cells. Strikingly, forced activation of Toll signaling or Toll-related receptor (TRR) signaling in scrib clones transforms scrib cells from losers to supercompetitors, resulting in tumorous overgrowth of mutant clones. Mechanistically, Toll activation in scrib clones leads to c-Jun N-terminal kinase (JNK) activation and F-actin accumulation, which cause strong activation of the Hippo pathway effector Yorkie that blocks cell death and promotes cell proliferation. Our data suggest that Spn5 secreted from normal epithelial cells acts as a component of the extracellular surveillance system that facilitates elimination of pre-malignant cells from epithelium. Copyright © 2018 Elsevier Ltd. All rights reserved.

2011 Atlanta and Seattle Tolling Impact Survey | Transportation Secure Data

Science.gov Websites

Center | NREL Atlanta and Seattle Tolling Impact Survey 2011 Atlanta and Seattle Tolling Impact Survey The 2011 Tolling Impact Survey measured the impact of tolling on travel behavior in Atlanta Transportation and the Urban Partnership Agreement, the Volpe Center conducted the survey. Methodology The

Particulate matter triggers depressive-like response associated with modulation of inflammatory cytokine homeostasis and brain-derived neurotrophic factor signaling pathway in mice.

PubMed

Liu, Xuemei; Qian, Xin; Xing, Jing; Wang, Jinhua; Sun, Yixuan; Wang, Qin'geng; Li, Huiming

2018-04-23

Particulate matter (PM) exposure may contribute to depressive-like response in mice. However, few studies have evaluated the adaptive impacts of long-term PM exposure on depressive-like response associated with systemic inflammation and brain-derived neurotrophic factor (BDNF) signaling pathway. We studied the association among depressive-like behaviors, mRNA levels of pro- and anti-inflammatory cytokines, and the expression of BDNF signaling pathway in mice by long-term PM exposure. C57BL/6 male mice were exposed to ambient air alongside control mice breathing air filtered through a high-efficiency air PM (HEPA) filter. Depressive-like behaviors were assessed together with pro-inflammatory, anti-inflammatory cytokine mRNA levels and the modulation of BDNF pathway in hippocampus and olfactory-bulb of mice exposed to PM for 4, 8, and 12 weeks. Exposure to HEPA filtered air for 4 weeks may exert antidepressant like effects in mice. Pro-inflammatory cytokines were up-regulated while the expression of BDNF, its high-affinity receptor tropomyosin-related kinase B (TrkB), and the transcription factor cAMP-response-element binding protein (CREB) were down-regulated in ambient air mice. However, after 8 weeks, there was no significant difference in the rate of depressive-like behaviors between the two groups. After 12 weeks, mice exposed to ambient air again had a higher rate of depressive-like behaviors, significant up-regulation of pro-inflammatory cytokines, down-regulation of interleukin-10 (IL-10), BDNF, TrkB, and CREB than HEPA mice. Ultrafine PM in brain tissues of mice exposed to ambient air was observed. Our results suggest continuous high-level PM exposure alters the depressive-like response in mice and induces a damage-repair-imbalance reaction.

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

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

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

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

Guide for geometric design and operational factors that impact truck use of toll roads.

DOT National Transportation Integrated Search

2010-09-01

Texas has approximately 300 miles of toll roads, predominantly in the three largest and : most congested urban areas of Austin, Dallas, and Houston. The Texas Turnpike Authority : (TTA) Division of the Texas Department of Transportation (TxDOT) and t...

Protective Effect of Ginsenosides Rg1 and Re on Lipopolysaccharide-Induced Sepsis by Competitive Binding to Toll-Like Receptor 4

PubMed Central

Su, Fei; Xue, Yin; Wang, Yuemin; Zhang, Lili; Chen, Wangxue

2015-01-01

We previously demonstrated that ginsenosides Rg1 and Re enhanced the immune response in C3H/HeB mice but not in C3H/HeJ mice carrying a mutation in the Tlr4 gene. The results of the present study showed that both Rg1 and Re inhibited mRNA expression and production of proinflammatory mediators that included tumor necrosis factor α, interleukin-1β, interleukin-6, cyclooxygenase-2, and inducible nitric oxide synthase from lipopolysaccharide (LPS)-stimulated macrophages. Rg1 was found to be distributed both extracellularly and intracellularly but Re was located only extracellularly to compete with LPS for binding to Toll-like receptor 4. Preinjection of Rg1 and Re into rats suppressed LPS-induced increases in body temperature, white blood cell counts, and levels of serum proinflammatory mediators. Preinjection of Rg1 and Re into mice prevented the LPS-induced decreases in total white blood cell counts and neutrophil counts, inhibited excessive expression of multiple proinflammatory mediators, and successfully rescued 100% of the mice from sepsis-associated death. More significantly, when administered after lethal LPS inoculation, Rg1, but not Re, still showed a potent antisepsis effect and protected 90% of the mice from death. The better protection efficacy of Rg1 could result from its intracellular distribution, suggesting that Rg1 may be an ideal antisepsis agent. PMID:26149990

Expression of microRNA-155 correlates positively with the expression of Toll-like receptor 7 and modulates hepatitis B virus via C/EBP-β in hepatocytes.

PubMed

Sarkar, N; Panigrahi, R; Pal, A; Biswas, A; Singh, S P; Kar, S K; Bandopadhyay, M; Das, D; Saha, D; Kanda, T; Sugiyama, M; Chakrabarti, S; Banerjee, A; Chakravarty, R

2015-10-01

Effective recognition of viral infection and successive activation of antiviral innate immune responses are vital for host antiviral defence, which largely depends on multiple regulators, including Toll-like receptors (TLRs) and microRNAs. Several early reports suggest that specific TLR-mediated immune responses can control hepatitis B virus (HBV) replication and express differentially with disease outcome. Considering the versatile function of miR-155 in the TLR-mediated innate immune response, we aimed to study the association between miR-155 and TLRs and their subsequent impact on HBV replication using both a HBV-replicating stable cell line (HepG2.2.15) and HBV-infected liver biopsy and serum samples. Our results showed that miR-155 was suppressed during HBV infection and a subsequent positive correlation of miR-155 with TLR7 activation was noted. Further, ectopic expression of miR-155 in vitro reduced HBV load as evidenced from reduced viral DNA, mRNA and subsequently reduced level of secreted viral antigens (HBsAg and HBeAg). Our results further suggested that CCAAT/enhancer-binding protein-β (C/EBP-β), a positive regulator of HBV transcription, was inhibited by miR-155. Taken together, our study established a correlation between miR-155 and TLR7 during HBV infection and also demonstrated in vitro that increased miR-155 level could help to reduce HBV viral load by targeting C/EBP-β. © 2015 John Wiley & Sons Ltd.

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.

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

Toll-Like Receptor 2 Mediates Cellular Activation by the B Subunits of Type II Heat-Labile Enterotoxins

PubMed Central

Hajishengallis, George; Tapping, Richard I.; Martin, Michael H.; Nawar, Hesham; Lyle, Elizabeth A.; Russell, Michael W.; Connell, Terry D.

2005-01-01

The type II heat-labile enterotoxins (LT-IIa and LT-IIb) of Escherichia coli have an AB5 subunit structure similar to that of cholera toxin (CT) and other type I enterotoxins, despite significant differences in the amino acid sequences of their B subunits and different ganglioside receptor specificities. LT-II holotoxins and their nontoxic B subunits display unique properties as immunological adjuvants distinct from those of CT and its B subunits. In contrast to type II holotoxins, the corresponding pentameric B subunits, LT-IIaB and LT-IIbB, stimulated cytokine release in both human and mouse cells dependent upon Toll-like receptor 2 (TLR2). Induction of interleukin-1β (IL-1β), IL-6, IL-8, or tumor necrosis factor alpha in human THP-1 cells by LT-IIaB or LT-IIbB was inhibited by anti-TLR2 but not by anti-TLR4 antibody. Furthermore, transient expression of TLR1 and TLR2 in human embryonic kidney 293 cells resulted in activation of a nuclear factor-κB-dependent luciferase gene in response to LT-IIaB or LT-IIbB. Moreover, peritoneal macrophages from TLR2-deficient mice failed to respond to LT-IIaB or LT-IIbB, in contrast to wild-type or TLR4-deficient cells. These results demonstrate that besides their established binding to gangliosides, the B subunits of type II enterotoxins also interact with TLR2. Although a ganglioside-nonbinding mutant (T34I) of LT-IIaB effectively induced cytokine release, a phenotypically similar point mutation (T13I) in LT-IIbB abrogated cytokine induction, suggesting a variable requirement for gangliosides as coreceptors in TLR2 agonist activity. TLR2-dependent activation of mononuclear cells by type II enterotoxin B subunits appears to be a novel mechanism whereby these molecules may exert their immunomodulatory and adjuvant activities. PMID:15731031

Common variants in toll-like receptor 4 confer susceptibility to Alzheimer's disease in a Han Chinese population.

PubMed

Yu, Jin-Tai; Miao, Dan; Cui, Wei-Zhen; Ou, Jiang-Rong; Tian, Yan; Wu, Zhong-Chen; Zhang, Wei; Tan, Lan

2012-05-01

Toll-like receptor 4 (TLR4) represents a reasonable functional and positional candidate gene for Alzheimer's disease (AD) as it is located within the previous identified linkage region of AD on chromosome 9q, and functionally is involved in the microglia-mediated inflammatory response, amyloid-β (Aβ) plaque formation and Aβ clearance. To test whether variants in the TLR4 gene are associated with late-onset AD (LOAD), we organized a multicenter study of 785 subjects (399 cases and 386 matched controls) in a Han Chinese population. Ten single nucleotide polymorphisms (SNPs) that span the TLR4 gene, from approximately 5 kb of the predicted 5'-untranslated region (UTR) to approximately 6 kb of the predicted 3'- UTR, were selected and their associations with LOAD risk factors were assessed. With respect to allelic diversity, the minor alleles of seven SNPs (rs10759930, rs1927914, rs1927911, rs12377632, rs2149356, rs7037117, and rs7045953) in TLR4 showed consistent protective effects against the risk of developing LOAD. With regard to genotypic diversity, individuals carrying at least one minor allele of each SNP above had a consistently lower risk of LOAD than those with no copies of the minor alleles (ORs ranging from 0.445 to 0.637). rs7045953, located in the 3'-UTR of TLR4, was most strongly associated with LOAD, and when incorporated into a haplotype with rs10759930, the strongest association was detected (P = 1.7x10-6, Pc s1.0x10-4). Our data suggests that the TLR4 gene contributes to the susceptibility for LOAD in Han Chinese.

[The effect of Toll-like receptor 4 in nicotine suppressing the osteogenic potential of periodontal ligament stem cells].

PubMed

Luan, Yan; Deqin, Yang

2017-08-01

Objective To explore the impact of nicotine on proliferation and osteogenic capability of periodontal ligament stem cells (PDLSCs), and the role of Toll-like receptor 4 (TLR4) in nicotine, suppressing the osteogenic capability of PDLSCs. Methods PDLSCs were cultured in vitro, and the flow cytometer was used to identify the surface antigen markers of PDLSCs. WST-1 was used to detect the proliferation ability of PDLSCs, which were stimulated by different concentrations of nicotine. Alizarin red staining was used to observe the formation of mineralized nodules after PDLSCs stimulation with different concentrations of nicotine. Real-time polymerase chain reaction (RT-PCR) and Western blot were used to detect the change in osteogenic potential of PDLSCs stimulated by nicotine, after TAK-242, and with the inhibitor of TLR4. Results PDLSCs expressed mesenchymal stem cell-associated markers CD90 and CD105. When the concentration of nicotine was 10⁻⁴ mol·L⁻¹, the PDLSC proliferation could be suppressed after 3 d compared with the control group (P<0.05). The amount of mineralized nodules reduced after osteogenic differentiation at 21 d by alizarin red staining. RT-PCR and Western blot showed the expression levels of alkaline phosphatase (ALP), and osteocalcin (OCN), and the Runt-related transcription factor-2 (Runx-2) were lower than in the control group when nicotine suppressed the PDLSCs (P<0.05). This effect was attenuated after TAK-242 was added. Conclusion Nicotine suppresses the proliferation and osteogenic capability of PDLSCs, which may be regulated by TLR4.

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

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.

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.

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

Molecular cloning of Salmo salar Toll-like receptors (TLR1, TLR22, TLR5M and TLR5S) and expression analysis in SHK-1 cells during Piscirickettsia salmonis infection.

PubMed

Salazar, C; Haussmann, D; Kausel, G; Figueroa, J

2016-02-01

In fish, the innate immune system is the primary response against infection. Toll-like receptors (TLRs) recognize pathogens through pathogen-associated molecular patterns (PAMPs), and some target molecules of TLRs are homologous between fish and mammals. Piscirickettsia salmonis is one of the main pathogens affecting the salmon industry in Chile. Better knowledge of mechanisms underlying its invasive capacity and recognition of target cells is crucial for vaccine development. Therefore, Salmo salar L. TLR1, TLR22, membrane TLR5M and soluble TLR5S sequences were cloned, and expression kinetics were analysed by RT-qPCR in salmon head kidney cells (SHK-1) infected with three different P. salmonis preparations: alive, formaldehyde treated, extract. Clearly, all analysed TLRs were expressed and transcription level changes were revealed at 2 hpi, 12 or 16 hpi and 24 hpi depending on P. salmonis infection scheme. Increased IL1-beta expression confirmed TLR pathway response. Furthermore, significant expression modulations of several members of the TLR pathway in this in vitro model suggest that P. salmonis extract rather than formaldehyde-inactivated bacteria might strengthen the salmon immune system. © 2015 John Wiley & Sons Ltd.

Ebola Virus Modulates Transforming Growth Factor β Signaling and Cellular Markers of Mesenchyme-Like Transition in Hepatocytes

PubMed Central

Wahl-Jensen, Victoria; Safronetz, David; Trost, Brett; Hoenen, Thomas; Arsenault, Ryan; Feldmann, Friederike; Traynor, Dawn; Postnikova, Elena; Kusalik, Anthony; Napper, Scott; Blaney, Joseph E.; Feldmann, Heinz; Jahrling, Peter B.

2014-01-01

ABSTRACT Ebola virus (EBOV) causes a severe hemorrhagic disease in humans and nonhuman primates, with a median case fatality rate of 78.4%. Although EBOV is considered a public health concern, there is a relative paucity of information regarding the modulation of the functional host response during infection. We employed temporal kinome analysis to investigate the relative early, intermediate, and late host kinome responses to EBOV infection in human hepatocytes. Pathway overrepresentation analysis and functional network analysis of kinome data revealed that transforming growth factor (TGF-β)-mediated signaling responses were temporally modulated in response to EBOV infection. Upregulation of TGF-β signaling in the kinome data sets correlated with the upregulation of TGF-β secretion from EBOV-infected cells. Kinase inhibitors targeting TGF-β signaling, or additional cell receptors and downstream signaling pathway intermediates identified from our kinome analysis, also inhibited EBOV replication. Further, the inhibition of select cell signaling intermediates identified from our kinome analysis provided partial protection in a lethal model of EBOV infection. To gain perspective on the cellular consequence of TGF-β signaling modulation during EBOV infection, we assessed cellular markers associated with upregulation of TGF-β signaling. We observed upregulation of matrix metalloproteinase 9, N-cadherin, and fibronectin expression with concomitant reductions in the expression of E-cadherin and claudin-1, responses that are standard characteristics of an epithelium-to-mesenchyme-like transition. Additionally, we identified phosphorylation events downstream of TGF-β that may contribute to this process. From these observations, we propose a model for a broader role of TGF-β-mediated signaling responses in the pathogenesis of Ebola virus disease. IMPORTANCE Ebola virus (EBOV), formerly Zaire ebolavirus, causes a severe hemorrhagic disease in humans and nonhuman

Tuning the Fano factor of graphene via Fermi velocity modulation

NASA Astrophysics Data System (ADS)

Lima, Jonas R. F.; Barbosa, Anderson L. R.; Bezerra, C. G.; Pereira, Luiz Felipe C.

2018-03-01

In this work we investigate the influence of a Fermi velocity modulation on the Fano factor of periodic and quasi-periodic graphene superlattices. We consider the continuum model and use the transfer matrix method to solve the Dirac-like equation for graphene where the electrostatic potential, energy gap and Fermi velocity are piecewise constant functions of the position x. We found that in the presence of an energy gap, it is possible to tune the energy of the Fano factor peak and consequently the location of the Dirac point, by a modulation in the Fermi velocity. Hence, the peak of the Fano factor can be used experimentally to identify the Dirac point. We show that for higher values of the Fermi velocity the Fano factor goes below 1/3 at the Dirac point. Furthermore, we show that in periodic superlattices the location of Fano factor peaks is symmetric when the Fermi velocity vA and vB is exchanged, however by introducing quasi-periodicity the symmetry is lost. The Fano factor usually holds a universal value for a specific transport regime, which reveals that the possibility of controlling it in graphene is a notable result.

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

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.

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 .

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

The vitamin D analogue paricalcitol attenuates hepatic ischemia/reperfusion injury through down-regulation of Toll-like receptor 4 signaling in rats

PubMed Central

Kim, Min Sung; Lee, Soyoung; Jung, Namhee; Lee, Kiho; Choi, Jinwoo; Kim, Sang-Hoon; Jun, Jinhyun; Lee, Won-Mee; Chang, Yeonsoo

2016-01-01

Introduction Recent studies have revealed that vitamin D and its synthetic analogues have a protective effect on experimental ischemia/reperfusion (I/R) models in several organs, but little is known about its effect on the liver. The aim of this study was to evaluate the beneficial effects of vitamin D in a model of liver I/R in rats, focusing on Toll-like receptor (TLR) 4 signaling, which has been shown to be involved in I/R injury. Material and methods Twenty-four male Wistar rats were randomized into four groups: Saline + Sham, Saline + I/R, Paricalcitol + Sham, and Paricalcitol + I/R. A synthetic vitamin D2 analogue, paricalcitol, was intraperitoneally injected 24 h prior to surgery. The animals were subjected to 60 min of partial warm ischemia (70%), followed by reperfusion for 6 h on the same day. The ischemic lobe of the liver and blood were collected for molecular biochemical analyses. Results Liver damage following I/R was diminished by pretreatment with paricalcitol. Pretreatment with paricalcitol decreased the levels of pro-inflammatory mediators, such as interleukin (IL)-1β, tumor necrosis factor (TNF)-α, and macrophage migration inhibitory factor (MIF), in both plasma and liver tissue. In addition, pretreatment with paricalcitol markedly down-regulated the expression of TLR4, HMGB1, TNF-α and NF-κB. Conclusions The vitamin D analogue paricalcitol attenuates hepatic I/R injury through down-regulation of the TLR4 signaling pathway and might be considered to be a potential nutritional therapeutic agent against I/R injury in the liver. PMID:28261302

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.

8. INTERIOR OF TOLL PLAZA OBSERVATION TOWER, LOOKING NORTH. ARTELUAR ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

8. INTERIOR OF TOLL PLAZA OBSERVATION TOWER, LOOKING NORTH. ARTELUAR COOK, ACTING SUPERVISOR, IS AT THE HELM. - Chicago Skyway Toll Bridge, Toll Plaza & Service Building, 8801 South Anthony Avenue, Chicago, Cook County, IL

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.

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.

Toll-Like Receptor Responses to Peste des petits ruminants Virus in Goats and Water Buffalo

PubMed Central

Dhanasekaran, Sakthivel; Biswas, Moanaro; Vignesh, Ambothi R.; Ramya, R.; Raj, Gopal Dhinakar; Tirumurugaan, Krishnaswamy G.; Raja, Angamuthu; Kataria, Ranjit S.; Parida, Satya; Subbiah, Elankumaran

2014-01-01

Ovine rinderpest or goat plague is an economically important and contagious viral disease of sheep and goats, caused by the Peste des petits ruminants virus (PPRV). Differences in susceptibility to goat plague among different breeds and water buffalo exist. The host innate immune system discriminates between pathogen associated molecular patterns and self antigens through surveillance receptors known as Toll like receptors (TLR). We investigated the role of TLR and cytokines in differential susceptibility of goat breeds and water buffalo to PPRV. We examined the replication of PPRV in peripheral blood mononuclear cells (PBMC) of Indian domestic goats and water buffalo and demonstrated that the levels of TLR3 and TLR7 and downstream signalling molecules correlation with susceptibility vs resistance. Naturally susceptible goat breeds, Barbari and Tellichery, had dampened innate immune responses to PPRV and increased viral loads with lower basal expression levels of TLR 3/7. Upon stimulation of PBMC with synthetic TLR3 and TLR7 agonists or PPRV, the levels of proinflammatory cytokines were found to be significantly higher while immunosuppressive interleukin (IL) 10 levels were lower in PPRV resistant Kanni and Salem Black breeds and water buffalo at transcriptional level, correlating with reduced viralloads in infected PBMC. Water buffalo produced higher levels of interferon (IFN) α in comparison with goats at transcriptional and translational levels. Pre-treatment of Vero cells with human IFNα resulted in reduction of PPRV replication, confirming the role of IFNα in limiting PPRV replication. Treatment with IRS66, a TLR7 antagonist, resulted in the reduction of IFNα levels, with increased PPRV replication confirming the role of TLR7. Single nucleotide polymorphism analysis of TLR7 of these goat breeds did not show any marked nucleotide differences that might account for susceptibility vs resistance to PPRV. Analyzing other host genetic factors might provide

A sustained increase in plasma NEFA upregulates the Toll-like receptor network in human muscle.

PubMed

Hussey, Sophie E; Lum, Helen; Alvarez, Andrea; Cipriani, Yolanda; Garduño-Garcia, Jesús; Anaya, Luis; Dube, John; Musi, Nicolas

2014-03-01

Insulin-sensitive tissues (muscle, liver) of individuals with obesity and type 2 diabetes mellitus are in a state of low-grade inflammation, characterised by increased Toll-like receptor (TLR) expression and TLR-driven signalling. However, the cause of this mild inflammatory state is unclear. We tested the hypothesis that a prolonged mild increase in plasma NEFA will increase TLR expression and TLR-driven signalling (nuclear factor κB [NFκB] and mitogen-activated kinase [MAPK]) and impair insulin action in muscle of lean healthy individuals. Twelve lean, normal-glucose-tolerant participants were randomised to receive a 48 h infusion (30 ml/h) of saline or Intralipid followed by a euglycaemic-hyperinsulinaemic clamp. Vastus lateralis muscle biopsies were performed before and during the clamp. Lipid infusion impaired insulin-stimulated IRS-1 tyrosine phosphorylation and reduced peripheral insulin sensitivity (p < 0.01). The elevation in circulating NEFA increased expression of TLR3, TLR4 and TLR5, and several MAPK (MAPK8, MAP4K4, MAP2K3) and inhibitor of κB kinase-NFκB (CHUK [IKKA], c-REL [REL] and p65 [RELA, NFKB3, p65]) signalling genes (p < 0.05). The lipid infusion also increased extracellular signal-regulated kinase (ERK) phosphorylation (p < 0.05) and tended to reduce the content of inhibitor of kappa Bα (p = 0.09). The muscle content of most diacylglycerol, ceramide and acylcarnitine species was unaffected. In summary, insulin resistance induced by prolonged low-dose lipid infusion occurs together with increased TLR-driven inflammatory signalling and impaired insulin-stimulated IRS-1 tyrosine phosphorylation. A sustained, mild elevation in plasma NEFA is sufficient to increase TLR expression and TLR-driven signalling (NFκB and MAPK) in lean individuals. The activation of this pathway by NEFA may be involved in the pathogenesis of insulin resistance in humans. ClinicalTrials.gov NCT01740817.

Epigallocatechin gallate (EGCG) suppresses lipopolysaccharide-induced Toll-like receptor 4 (TLR4) activity via 67 kDa laminin receptor (67LR) in 3T3-L1 adipocytes.

PubMed

Bao, Suqing; Cao, Yanli; Zhou, Haicheng; Sun, Xin; Shan, Zhongyan; Teng, Weiping

2015-03-18

Obesity-related insulin resistance is associated with chronic systemic low-grade inflammation, and toll-like receptor 4 (TLR4) regulates inflammation. We investigated the pathways involved in epigallocatechin gallate (EGCG) modulation of insulin and TLR4 signaling in adipocytes. Inflammation was induced in adipocytes by lipopolysaccharide (LPS). An antibody against the 67 kDa laminin receptor (67LR, to which EGCG exclusively binds) was used to examine the effect of EGCG on TLR4 signaling, and a TLR4/MD-2 antibody was used to inhibit TLR4 activity and to determine the insulin sensitivity of differentiated 3T3-L1 adipocytes. We found that EGCG dose-dependently inhibited LPS stimulation of adipocyte inflammation by reducing inflammatory mediator and cytokine levels (IKKβ, p-NF-κB, TNF-α, and IL-6). Pretreatment with the 67LR antibody prevented EGCG inhibition of inflammatory cytokines, decreased glucose transporter isoform 4 (GLUT4) expression, and inhibited insulin-stimulated glucose uptake. TLR4 inhibition attenuated inflammatory cytokine levels and increased glucose uptake by reversing GLUT4 levels. These data suggest that EGCG suppresses TLR4 signaling in LPS-stimulated adipocytes via 67LR and attenuates insulin-stimulated glucose uptake associated with decreased GLUT4 expression.

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

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.

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