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Sample records for infection impairs toll-like

  1. Immaturity of infection control in preterm and term newborns is associated with impaired toll-like receptor signaling.

    PubMed

    Sadeghi, Kambis; Berger, Angelika; Langgartner, Michaela; Prusa, Andrea-Romana; Hayde, Michael; Herkner, Kurt; Pollak, Arnold; Spittler, Andreas; Forster-Waldl, Elisabeth

    2007-01-15

    The impaired infection control related to the functional immaturity of the neonatal immune system is an important cause of infection in preterm newborns. We previously reported that constitutive Toll-like receptor (TLR) 4 expression and cytokine secretion on lipopolysaccharide (LPS) stimulation increases with gestational age. Here, we analyzed constitutive monocyte TLR2 expression and evaluated the expression profiles of the proximal downstream adapter molecule myeloid differentiation factor 88 (MyD88). We further investigated activation of protein kinases p38 and extracellular regulated kinsase (ERK) 1/2 in CD14 monocytes after ex vivo stimulation with bacterial TLR ligands (LPS and lipoteichoic acid [LTA]). The functional outcome of the stimulation was determined by cytokine secretion. Monocytes from 31 preterm newborns (<30 weeks of gestation, n=16; 30-37 weeks of gestation, n=15), 10 term newborns, and 12 adults were investigated. In contrast to TLR4 expression, TLR2 levels did not differ between age groups. However, MyD88 levels were significantly lower in preterm newborns. Activation of p38 and ERK1/2 was impaired in all newborn age groups after stimulation with TLR-specific ligands. Accordingly, after LTA stimulation, the levels of interleukin (IL)-1 beta , IL-6, and IL-8 cytokine production were substantially lower (P<.001) in preterm newborns than in adults. The reduced functional response to bacterial cell wall components appears to be part of the functional immaturity of the neonatal immune system and might predispose premature newborns to bacterial infection.

  2. 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

  3. Toll-Like Receptor Gene Expression during Trichinella spiralis Infection

    PubMed Central

    Kim, Sin; Park, Mi Kyung; Yu, Hak Sun

    2015-01-01

    In Trichinella spiralis infection, type 2 helper T (Th2) cell-related and regulatory T (Treg) cell-related immune responses are the most important immune events. In order to clarify which Toll-like receptors (TLRs) are closely associated with these responses, we analyzed the expression of mouse TLR genes in the small intestine and muscle tissue during T. spiralis infection. In addition, the expression of several chemokine- and cytokine-encoding genes, which are related to Th2 and Treg cell mediated immune responses, were analyzed in mouse embryonic fibroblasts (MEFs) isolated from myeloid differentiation factor 88 (MyD88)/TIR-associated proteins (TIRAP) and Toll receptor-associated activator of interferons (TRIF) adapter protein deficient and wild type (WT) mice. The results showed significantly increased TLR4 and TLR9 gene expression in the small intestine after 2 weeks of T. spiralis infection. In the muscle, TLR1, TLR2, TLR5, and TLR9 gene expression significantly increased after 4 weeks of infection. Only the expression of the TLR4 and TLR9 genes was significantly elevated in WT MEF cells after treatment with excretory-secretory (ES) proteins. Gene expression for Th2 chemokine genes were highly enhanced by ES proteins in WT MEF cells, while this elevation was slightly reduced in MyD88/TIRAP-/- MEF cells, and quite substantially decreased in TRIF-/- MEF cells. In contrast, IL-10 and TGF-β expression levels were not elevated in MyD88/TIRAP-/- MEF cells. In conclusion, we suggest that TLR4 and TLR9 might be closely linked to Th2 cell and Treg cell mediated immune responses, although additional data are needed to convincingly prove this observation. PMID:26323841

  4. Toll-Like Receptor 2 Targeted Rectification of Impaired CD8+ T Cell Functions in Experimental Leishmania donovani Infection Reinstates Host Protection

    PubMed Central

    Bandyopadhyay, Syamdas; Kar Mahapatra, Santanu; Paul Chowdhury, Bidisha; Kumar Jha, Mukesh; Das, Shibali; Halder, Kuntal; Bhattacharyya Majumdar, Suchandra; Saha, Bhaskar; Majumdar, Subrata

    2015-01-01

    Leishmania donovani, a protozoan parasite, causes the disease visceral leishmanisis (VL), characterized by inappropriate CD8+ T-cell activation. Therefore, we examined whether the Toll-like Receptor 2 (TLR2) ligand Ara-LAM, a cell wall glycolipid from non-pathogenic Mycobacterium smegmatis, would restore CD8+ T-cell function during VL. We observed that by efficient upregulation of TLR2 signaling-mediated NF-κB translocation and MAPK signaling in CD8+ T-cells (CD25+CD28+IL-12R+IFN-γR+), Ara-LAM triggered signaling resulted in the activation of T-bet, which in turn, induced transcription favourable histone modification at the IFN-γ, perforin, granzyme-B promoter regions in CD8+ T-cells. Thus, we conclude that Ara-LAM induced efficient activation of effector CD8+ T-cells by upregulating the expression of IFN-γ, perforin and granzyme-B in an NF-κB and MAPK induced T-bet dependent manner in VL. PMID:26559815

  5. Toll-Like Receptor 9 Contributes to Defense against Acinetobacter baumannii Infection

    PubMed Central

    Noto, Michael J.; Boyd, Kelli L.; Burns, William J.; Varga, Matthew G.; Peek, Richard M.

    2015-01-01

    Acinetobacter baumannii is a common nosocomial pathogen capable of causing severe diseases associated with significant morbidity and mortality in impaired hosts. Pattern recognition receptors, such as the Toll-like receptors (TLRs), play a key role in pathogen detection and function to alert the immune system to infection. Here, we examine the role for TLR9 signaling in response to A. baumannii infection. In a murine model of A. baumannii pneumonia, TLR9−/− mice exhibit significantly increased bacterial burdens in the lungs, increased extrapulmonary bacterial dissemination, and more severe lung pathology compared with those in wild-type mice. Following systemic A. baumannii infection, TLR9−/− mice have significantly increased bacterial burdens in the lungs, as well as decreased proinflammatory cytokine and chemokine production. These results demonstrate that TLR9-mediated pathogen detection is important for host defense against the opportunistic pathogen Acinetobacter baumannii. PMID:26238713

  6. Bovine Viral Diarrhea Virus Type 2 Impairs Macrophage Responsiveness to Toll-Like Receptor Ligation with the Exception of Toll-Like Receptor 7

    PubMed Central

    Schaut, Robert G.; Ridpath, Julia F.; Sacco, Randy E.

    2016-01-01

    Bovine viral diarrhea virus (BVDV) is a member of the Flaviviridae family. BVDV isolates are classified into two biotypes based on the development of cytopathic (cp) or non-cytopathic (ncp) effects in epithelial cell culture. BVDV isolates are further separated into species, BVDV1 and 2, based on genetic differences. Symptoms of BVDV infection range from subclinical to severe, depending on strain virulence, and may involve multiple organ systems and induction of a generalized immunosuppression. During BVDV-induced immune suppression, macrophages, critical to innate immunity, may have altered pathogen recognition receptor (PRR) signaling, including signaling through toll-like receptors (TLRs). Comparison of BVDV 2 strains with different biotypes and virulence levels is valuable to determining if there are differences in host macrophage cellular responses between viral phenotypes. The current study demonstrates that cytopathic (cp), noncytopathic (ncp), high (hv) or low virulence (lv) BVDV2 infection of bovine monocyte-derived macrophages (MDMΦ) result in differential expression of pro-inflammatory cytokines compared to uninfected MDMΦ. A hallmark of cp BVDV2 infection is IL-6 production. In response to TLR2 or 4 ligation, as might be observed during secondary bacterial infection, cytokine secretion was markedly decreased in BVDV2-infected MDMΦ, compared to non-infected MDMΦ. Macrophages were hyporesponsive to viral TLR3 or TLR8 ligation. However, TLR7 stimulation of BVDV2-infected MDMΦ induced cytokine secretion, unlike results observed for other TLRs. Together, these data suggest that BVDV2 infection modulated mRNA responses and induced a suppression of proinflammatory cytokine protein responses to TLR ligation in MDMΦ with the exception of TLR7 ligation. It is likely that there are distinct differences in TLR pathways modulated following BVDV2 infection, which have implications for macrophage responses to secondary infections. PMID:27420479

  7. Toll-like receptor 4 polymorphisms in dengue virus-infected children.

    PubMed

    Djamiatun, Kis; Ferwerda, Bart; Netea, Mihai G; van der Ven, André J A M; Dolmans, Wil M V; Faradz, Sultana M H

    2011-08-01

    Differential viral recognition by cells bearing Toll-like receptor 4 (TLR4) polymorphisms Asp299Gly and Thr399Ile may influence susceptibility and severity of dengue virus infection. In central Java, Indonesia, we investigated 201 children with dengue hemorrhagic fever (DHF) and 179 healthy controls. Patients and controls were mostly ethnic Javanese. A nearly complete cosegregation of the two mutations was observed. The TLR4 299/399 genotype was found in five patients and four controls. Prevalence of the TLR4 299/399 genotype did not differ significantly between controls and DHF patients or between patients with different severities of DHF. Also, vascular leakage in patients with different TLR4 genotypes did not differ. Thus, the 299/399 TLR4 haplotype has only minor influence on susceptibility and severity of complicated dengue virus infection.

  8. Toll-like receptor 4 deficiency impairs microglial phagocytosis of degenerating axons.

    PubMed

    Rajbhandari, Labchan; Tegenge, Million Adane; Shrestha, Shiva; Ganesh Kumar, Nishant; Malik, Adeel; Mithal, Aditya; Hosmane, Suneil; Venkatesan, Arun

    2014-12-01

    Microglia are rapidly activated in the central nervous system (CNS) in response to a variety of injuries, including inflammation, trauma, and stroke. In addition to modulation of the innate immune response, a key function of microglia is the phagocytosis of dying cells and cellular debris, which can facilitate recovery. Despite emerging evidence that axonal debris can pose a barrier to regeneration of new axons in the CNS, little is known of the cellular and molecular mechanisms that underlie clearance of degenerating CNS axons. We utilize a custom micropatterned microfluidic system that enables robust microglial-axon co-culture to explore the role of Toll-like receptors (TLRs) in microglial phagocytosis of degenerating axons. We find that pharmacologic and genetic disruption of TLR4 blocks induction of the Type-1 interferon response and inhibits phagocytosis of axon debris in vitro. Moreover, TLR4-dependent microglial clearance of unmyelinated axon debris facilitates axon outgrowth. In vivo, microglial phagocytosis of CNS axons undergoing Wallerian degeneration in a dorsal root axotomy model is impaired in adult mice in which TLR4 has been deleted. Since purinergic receptors can influence TLR4-mediated signaling, we also explored a role for the microglia P2 receptors and found that the P2X7R contributes to microglial clearance of degenerating axons. Overall, we identify TLR4 as a key player in axonal debris clearance by microglia, thus creating a more permissive environment for axonal outgrowth. Our findings have significant implications for the development of protective and regenerative strategies for the many inflammatory, traumatic, and neurodegenerative conditions characterized by CNS axon degeneration.

  9. [Progress on the role of Toll-like receptors in Candida albicans infections].

    PubMed

    Yun, Zhou; Jianping, Pan

    2016-05-25

    Toll like receptors (TLRs) are expressed mainly on innate immunocytes such as dendritic cells and macrophages, and may have the potential to recognize and bind to pathogen-associated molecular patterns (PAMPs) from Candida albicans, thereby triggering the downstream signals. The genetic polymorphism of TLRs is associated with susceptibility to Candida albicans. The activation of TLRs by PAMPs from Candida albicans can induce the production of proinflammatory cytokines that play key roles in the anti-infection of Candida albicans. However, in order to evade the immune response of host,Candida albicans can also change its bacterial phase. Understanding of the interaction between TLRs and Candida albicans will provide novel evidence to further clarify the mechanisms of anti-fungal immune response. PMID:27651197

  10. Role of Toll-like receptors in Helicobacter pylori infection and immunity

    PubMed Central

    Smith, Sinéad M

    2014-01-01

    The gram-negative bacterium Helicobacter pylori (H. pylori) infects the stomachs of approximately half of the world’s population. Although infection induces an immune response that contributes to chronic gastric inflammation, the response is not sufficient to eliminate the bacterium. H. pylori infection causes peptic ulcers, gastric cancer and mucosa-associated lymphoid tissue lymphoma. Disease outcome is linked to the severity of the host inflammatory response. Gastric epithelial cells represent the first line of innate immune defence against H. pylori, and respond to infection by initiating numerous cell signalling cascades, resulting in cytokine induction and the subsequent recruitment of inflammatory cells to the gastric mucosa. Pathogen recognition receptors of the Toll-like receptor (TLR) family mediate many of these cell signalling events. This review discusses recent findings on the role of various TLRs in the recognition of H. pylori in distinct cell types, describes the TLRs responsible for the recognition of individual H. pylori components and outlines the influence of innate immune activation on the subsequent development of the adaptive immune response. The mechanistic identification of host mediators of H. pylori-induced pathogenesis has the potential to reveal drug targets and opportunities for therapeutic intervention or prevention of H. pylori-associated disease by means of vaccines or immunomodulatory therapy. PMID:25133016

  11. Toll-Like Receptor-4 Dependent Small Intestinal Immune Responses Following Murine Arcobacter Butzleri Infection

    PubMed Central

    Heimesaat, Markus M.; Karadas, Gül; Fischer, André; Göbel, Ulf B.; Alter, Thomas; Bereswill, Stefan; Gölz, Greta

    2015-01-01

    Sporadic cases of gastroenteritis have been attributed to Arcobacter butzleri infection, but information about the underlying immunopathological mechanisms is scarce. We have recently shown that experimental A. butzleri infection induces intestinal, extraintestinal and systemic immune responses in gnotobiotic IL-10–/– mice. The aim of the present study was to investigate the immunopathological role of Toll-like Receptor-4, the receptor for lipopolysaccharide and lipooligosaccharide of Gram-negative bacteria, during murine A. butzleri infection. To address this, gnotobiotic IL-10–/– mice lacking TLR-4 were generated by broad-spectrum antibiotic treatment and perorally infected with two different A. butzleri strains isolated from a patient (CCUG 30485) or fresh chicken meat (C1), respectively. Bacteria of either strain stably colonized the ilea of mice irrespective of their genotype at days 6 and 16 postinfection. As compared to IL-10–/– control animals, TLR-4–/– IL-10–/– mice were protected from A. butzleri-induced ileal apoptosis, from ileal influx of adaptive immune cells including T lymphocytes, regulatory T-cells and B lymphocytes, and from increased ileal IFN-γ secretion. Given that TLR-4-signaling is essential for A. butzleri-induced intestinal inflammation, we conclude that bacterial lipooligosaccharide or lipopolysaccharide compounds aggravate intestinal inflammation and may thus represent major virulence factors of Arcobacter. Future studies need to further unravel the molecular mechanisms of TLR-4-mediated A. butzleri-host interactions. PMID:26716022

  12. Differential expression of Toll-like receptor 4 (TLR4) in healthy and infected canine endometrium.

    PubMed

    Chotimanukul, S; Sirivaidyapong, S

    2011-10-01

    This study provides the first report into immunohistochemical localization of Toll-like receptor (TLR) in the canine reproductive tract. TLR4 was investigated in endometrium during the estrous cycle and in pyometra. Pyometra is the most important pathological condition of the uterus due to bacterial infection in dogs. To protect against invading pathogens, the female reproductive tract has evolved immune mechanisms. TLRs are the cellular components of the afferent arm of the innate immune system. The expression of TLR4 was significantly higher in the endometrial stroma compared to the endometrial surface epithelium and glandular epithelium in proestrus. The glandular epithelium and stroma at the diestrous stage expressed TLR4 significantly higher than surface epithelium. Furthermore, when compared to other healthy groups, the glandular epithelium at diestrus also higher expressed TLR4 than other stages. The expression of TLR4 in the surface epithelium was higher in dogs with pyometra compared with all other groups. And, the surface epithelium of dogs suffering from pyometra also expressed TLR4 more intensely than the glandular epithelium. The innate immunity of infected canine endometrium response to bacterial infection is intensely extremely increased by the expression of TLR4. Furthermore, the different levels of TLR4 expression seems related to physiological changes in distinct cell types of endometrium, leukocytes populations, cytokines and sex hormones. PMID:21752456

  13. Toll-like receptors in prostate infection and cancer between bench and bedside

    PubMed Central

    Gambara, Guido; Cesaris, Paola; Nunzio, Cosimo; Ziparo, Elio; Tubaro, Andrea; Filippini, Antonio; Riccioli, Anna

    2013-01-01

    Toll-Like receptors (TLRs) are a family of evolutionary conserved transmembrane proteins that recognize highly conserved molecules in pathogens. TLR-expressing cells represent the first line of defence sensing pathogen invasion, triggering innate immune responses and subsequently priming antigen-specific adaptive immunity. In vitro and in vivo studies on experimental cancer models have shown both anti- and pro-tumoural activity of different TLRs in prostate cancer, indicating these receptors as potential targets for cancer therapy. In this review, we highlight the intriguing duplicity of TLR stimulation by pathogens: their protective role in cases of acute infections, and conversely their negative role in favouring hyperplasia and/or cancer onset, in cases of chronic infections. This review focuses on the role of TLRs in the pathophysiology of prostate infection and cancer by exploring the biological bases of the strict relation between TLRs and prostate cancer. In particular, we highlight the debated question of how reliable mutations or deregulated expression of TLRs are as novel diagnostic or prognostic tools for prostate cancer. So far, the anticancer activity of numerous TLR ligands has been evaluated in clinical trials only in organs other than the prostate. Here we review recent clinical trials based on the most promising TLR agonists in oncology, envisaging a potential application also in prostate cancer therapy. PMID:23551576

  14. Characterization of Toll-like receptor gene expression in goldfish (Carassius auratus) during Dactylogyrus intermedius infection.

    PubMed

    Tu, Xiao; Liu, Lei; Qi, Xiaozhou; Chen, Weichao; Wang, Gaoxue; Ling, Fei

    2016-10-01

    Toll-like receptors (TLRs), the first and best understood innate immune receptors, play a notable role in the innate immune system by sensing pathogenic agents and initiating appropriate immune responses. However, studies about the roles of fish TLRs in response to the infection of the ectoparasitic monogenean Dactylogyrus intermedius have been surprisingly vacant. In the present study, cDNA fragments of five members of TLRs family in goldfish (Carassius auratus) were cloned and the expression patterns of nine TLRs in five tissues at different time points during D. intermedius infection were subsequently investigated. We found that the expressions of TLR4, TLR5, TLR20 and TLR22 were significantly elevated after infection at some time points, of which the transcription of TLR5 was progressively increased nearly in all tissues, whereas the mRNA levels of other TLRs (TLR2, 3, 7, 9 and 21) were down-regulated or showed no significant change compared with the control at most time points. Additionally, this paper was also conducted to explore the expression of above TLRs after re-infected with D. intermedius. The results showed a significant upregulation of TLR4, TLR5 and TLR22 in all tested tissues at these two time points, especially the levels of TLR4 and TLR22 expression, were even higher comparing with the first infection. Besides, tissue-specific expression analysis revealed that spleen featured the highest expressions of almost all the TLR-encoding genes among detected tissues. The informations obtained here could be helpful towards understanding the functions of TLRs in response to parasitic infection in goldfish and provide new insights for the development of preventive and therapeutic approaches against D. intermedius infection.

  15. Characterization of Toll-like receptor gene expression in goldfish (Carassius auratus) during Dactylogyrus intermedius infection.

    PubMed

    Tu, Xiao; Liu, Lei; Qi, Xiaozhou; Chen, Weichao; Wang, Gaoxue; Ling, Fei

    2016-10-01

    Toll-like receptors (TLRs), the first and best understood innate immune receptors, play a notable role in the innate immune system by sensing pathogenic agents and initiating appropriate immune responses. However, studies about the roles of fish TLRs in response to the infection of the ectoparasitic monogenean Dactylogyrus intermedius have been surprisingly vacant. In the present study, cDNA fragments of five members of TLRs family in goldfish (Carassius auratus) were cloned and the expression patterns of nine TLRs in five tissues at different time points during D. intermedius infection were subsequently investigated. We found that the expressions of TLR4, TLR5, TLR20 and TLR22 were significantly elevated after infection at some time points, of which the transcription of TLR5 was progressively increased nearly in all tissues, whereas the mRNA levels of other TLRs (TLR2, 3, 7, 9 and 21) were down-regulated or showed no significant change compared with the control at most time points. Additionally, this paper was also conducted to explore the expression of above TLRs after re-infected with D. intermedius. The results showed a significant upregulation of TLR4, TLR5 and TLR22 in all tested tissues at these two time points, especially the levels of TLR4 and TLR22 expression, were even higher comparing with the first infection. Besides, tissue-specific expression analysis revealed that spleen featured the highest expressions of almost all the TLR-encoding genes among detected tissues. The informations obtained here could be helpful towards understanding the functions of TLRs in response to parasitic infection in goldfish and provide new insights for the development of preventive and therapeutic approaches against D. intermedius infection. PMID:27238769

  16. Polymorphisms of Toll-like receptors 2 and 4 in chronically infected hepatitis C patients from north-east Croatia.

    PubMed

    Perić, Magdalena; Bošnjak, Zinka; Šarkanj, Bojan; Barbić, Jerko; Antolović-Požgain, Arlen; Ružman, Nataša; Roksandić-Križan, Ivana; Vuković, Dubravka

    2015-01-01

    Chronic infection with hepatitis C virus (HCV) is caused by an inadequate immune response. Experimental data suggest that the impaired activation of Toll-like receptors (TLRs) 2 and 4 contributes to chronic infection. We assessed the distribution of three single-nucleotide polymorphisms (SNPs) in the TLR2 (Arg753Gln) and TLR4 (Asp299Gly/Thr399Ile) genes in individuals from north-east Croatia and their effect on the outcome of antiviral therapy. The study consisted of 60 chronically infected patients and 40 healthy subjects. TLR polymorphisms were determined by the PCR-based melting curve analysis. HCV genotyping was performed using the Linear Array Hepatitis C Virus Genotyping Test. Thirty-three patients were treated with standard interferon and ribavirin therapy, and their viral load was evaluated at weeks 28 and 53 after the beginning of therapy. The majority of chronic infections were caused by genotype 1 (77%), followed by genotypes 3 (15%) and 4 (7%). Patients with genotype 1 had higher viral loads than patients infected with other genotypes (P = 0.0428). Healthy individuals and patients with chronic infection had similar frequencies of TLR2-Arg753Gln and TLR4-Asp299Gly/Thr399Ile SNPs. Heterozygous and homozygous TLR4-Asp299Gly/Thr399Ile polymorphisms correlated with higher viral loads and delayed responses to antiviral therapy. We have provided the first evidence that TLR4 polymorphisms influence the success of antiviral therapy in our region. This suggests that therapeutic strategies should be adjusted not only according to HCV genotype but also to individual TLR polymorphism(s).

  17. Toll-Like Receptor 6 Plays an Important Role in Host Innate Resistance to Brucella abortus Infection in Mice

    PubMed Central

    de Almeida, Leonardo A.; Macedo, Gilson C.; Marinho, Fábio A. V.; Gomes, Marco T. R.; Corsetti, Patrícia P.; Silva, Aristóbolo M.; Cassataro, Juliana; Giambartolomei, Guillermo H.

    2013-01-01

    Brucella abortus is recognized by several Toll-like receptor (TLR)-associated pathways triggering proinflammatory responses that affect both the nature and intensity of the immune response. Previously, we demonstrated that B. abortus-mediated dendritic cell (DC) maturation and control of infection are dependent on the adaptor molecule MyD88. However, the involvement of all TLRs in response to B. abortus infection is not completely understood. Therefore, we decided to evaluate the requirement for TLR6 in host resistance to B. abortus. Here, we demonstrated that TLR6 is an important component for triggering an innate immune response against B. abortus. An in vitro luciferase assay indicated that TLR6 cooperates with TLR2 to sense Brucella and further activates NF-κB signaling. However, in vivo analysis showed that TLR6, not TLR2, is required for the efficient control of B. abortus infection. Additionally, B. abortus-infected dendritic cells require TLR6 to induce tumor necrosis factor alpha (TNF-α) and interleukin-12 (IL-12). Furthermore, our findings demonstrated that the mitogen-activated protein kinase (MAPK) signaling pathway is impaired in TLR2, TLR6, and TLR2/6 knockout (KO) DCs when infected with B. abortus, which may account for the lower proinflammatory cytokine production observed in TLR6 KO mouse dendritic cells. In summary, the results presented here indicate that TLR6 is required to trigger innate immune responses against B. abortus in vivo and is required for the full activation of DCs to induce robust proinflammatory cytokine production. PMID:23460520

  18. Toll-Like Receptor Polymorphisms and Susceptibility to Urinary Tract Infections in Adult Women

    PubMed Central

    Hawn, Thomas R.; Scholes, Delia; Li, Shuying S.; Wang, Hongwei; Yang, Yin; Roberts, Pacita L.; Stapleton, Ann E.; Janer, Marta; Aderem, Alan; Stamm, Walter E.; Zhao, Lue Ping; Hooton, Thomas M.

    2009-01-01

    Background Although behavioral risk factors are strongly associated with urinary tract infection (UTI) risk, the role of genetics in acquiring this disease is poorly understood. Methodology/Principal Findings To test the hypothesis that polymorphisms in Toll-like receptor (TLR) pathway genes are associated with susceptibility to UTIs, we conducted a population-based case-control study of women ages 18–49 years. We examined DNA variants in 9 TLR pathway genes in 431 recurrent cystitis (rUTI) cases, 400 pyelonephritis cases, and 430 controls with no history of UTIs. In the Caucasian subgroup of 987 women, polymorphism TLR4_A896G was associated with protection from rUTI, but not pyelonephritis, with an odds ratio (OR) of 0.54 and a 95% confidence interval (CI) of 0.31 to 0.96. Polymorphism TLR5_C1174T, which encodes a variant that abrogates flagellin-induced signaling, was associated with an increased risk of rUTI (OR(95%CI): 1.81 (1.00–3.08)), but not pyelonephritis. Polymorphism TLR1_G1805T was associated with protection from pyelonephritis (OR(95%CI): 0.53 (0.29–0.96)). Conclusions These results provide the first evidence of associations of TLR5 and TLR1 variants with altered risks of acquiring rUTI and pyelonephritis, respectively. Although these data suggest that TLR polymorphisms are associated with adult susceptibility to UTIs, the statistical significance was modest and will require further study including validation with independent cohorts. PMID:19543401

  19. Toll-like receptor 2 mediates high-fat diet-induced impairment of vasodilator actions of insulin

    PubMed Central

    Jang, Hyun-Ju; Kim, Hae-Suk; Hwang, Daniel H.; Quon, Michael J.

    2013-01-01

    Obesity is characterized by a chronic proinflammatory state that leads to endothelial dysfunction. Saturated fatty acids (SFA) stimulate Toll-like receptors (TLR) that promote metabolic insulin resistance. However, it is not known whether TLR2 mediates impairment of vascular actions of insulin in response to high-fat diet (HFD) to cause endothelial dysfunction. siRNA knockdown of TLR2 in primary endothelial cells opposed palmitate-stimulated expression of proinflammatory cytokines and splicing of X box protein 1 (XBP-1). Inhibition of unfolding protein response (UPR) reduced SFA-stimulated expression of TNFα. Thus, SFA stimulates UPR and proinflammatory response through activation of TLR2 in endothelial cells. Knockdown of TLR2 also opposed impairment of insulin-stimulated phosphorylation of eNOS and subsequent production of NO. Importantly, insulin-stimulated vasorelaxation of mesenteric arteries from TLR2 knockout mice was preserved even on HFD (in contrast with results from arteries examined in wild-type mice on HFD). We conclude that TLR2 in vascular endothelium mediates HFD-stimulated proinflammatory responses and UPR that accompany impairment of vasodilator actions of insulin, leading to endothelial dysfunction. These results are relevant to understanding the pathophysiology of the cardiovascular complications of diabetes and obesity. PMID:23531618

  20. Toll-Like Receptor 9 Activation Rescues Impaired Antibody Response in Needle-free Intradermal DNA Vaccination

    PubMed Central

    Arunachalam, Prabhu S.; Mishra, Ria; Badarinath, Krithika; Selvam, Deepak; Payeli, Sravan K.; Stout, Richard R.; Ranga, Udaykumar

    2016-01-01

    The delivery of plasmid DNA to the skin can target distinct subsets of dermal dendritic cells to confer a superior immune response. The needle-free immunization technology offers a reliable, safe and efficient means to administer intradermal (ID) injections. We report here that the ID injection of DNA vectors using an NF device (NF-ID) elicits a superior cell-mediated immune response, at much lesser DNA dosage, comparable in magnitude to the traditional intramuscular immunization. However, the humoral response is significantly impaired, possibly at the stage of B cell isotype switching. We found that the NF-ID administration deposits the DNA primarily on the epidermis resulting in a rapid loss of the DNA as well as the synthesized antigen due to the faster regeneration rate of the skin layers. Therefore, despite the immune-rich nature of the skin, the NF-ID immunization of DNA vectors may be limited by the impaired humoral response. Additional booster injections are required to augment the antibody response. As an alternative and a viable solution, we rescued the IgG response by coadministration of a Toll-like receptor 9 agonist, among other adjuvants examined. Our work has important implication for the optimization of the emerging needle-free technology for ID immunization. PMID:27658623

  1. Modulation of Toll-Like Receptor Activity by Leukocyte Ig-Like Receptors and Their Effects during Bacterial Infection

    PubMed Central

    Pilsbury, Louise E.; Allen, Rachel L.; Vordermeier, Martin

    2010-01-01

    Toll-like receptors (TLRs) are a potent trigger for inflammatory immune responses. Without tight regulation their activation could lead to pathology, so it is imperative to extend our understanding of the regulatory mechanisms that govern TLR expression and function. One family of immunoregulatory proteins which can provide a balancing effect on TLR activity are the Leukocyte Ig-like receptors (LILRs), which act as innate immune receptors for self-proteins. Here we describe the LILR family, their inhibitory effect on TLR activity in cells of the monocytic lineage, their signalling pathway, and their antimicrobial effects during bacterial infection. Agents have already been identified which enhances or inhibits LILR activity raising the future possibility that modulation of LILR function could be used as a means to modulate TLR activity. PMID:20634939

  2. Acanthamoeba infection in lungs of mice expressed by toll-like receptors (TLR2 and TLR4).

    PubMed

    Derda, Monika; Wojtkowiak-Giera, Agnieszka; Kolasa-Wołosiuk, Agnieszka; Kosik-Bogacka, Danuta; Hadaś, Edward; Jagodziński, Paweł P; Wandurska-Nowak, Elżbieta

    2016-06-01

    Toll-like receptors (TLRs) play a key role in the innate immune responses to a variety of pathogens including parasites. TLRs are among the most highly conserved in the evolution of the receptor family, localized mainly on cells of the immune system and on other cells such as lung cells. The aim of this study was to determine for the first time the expression of TLR2 and TLR4 in the lung of Acanthamoeba spp. infected mice using quantitative real-time polymerase chain reaction (Q-PCR) and immunohistochemical (IHC) staining. The Acanthamoeba spp. were isolated from a patient with Acanthamoeba keratitis (AK) (strain Ac 55) and from environmental samples of water from Malta Lake (Poznań, Poland - strain Ac 43). We observed a significantly increased level of expression of TLR2 as well as TLR4 mRNA from 2 to 30 days post Acanthamoeba infection (dpi) in the lungs of mice infected with Ac55 (KP120880) and Ac43 (KP120879) strains. According to our observations, increased TLR2 and TLR4 expression in the pneumocytes, interstitial cells and epithelial cells of the bronchial tree may suggest an important role of these receptors in protective immunity against Acanthamoeba infection in the lung. Moreover, increased levels of TLR2 and TLR4 mRNA expression in infected Acanthamoeba mice may suggest the involvement of these TLRs in the recognition of this amoeba pathogen-associated molecular pattern (PAMP). PMID:26940205

  3. Toll-Like Receptor-4 Dependent Intestinal Gene Expression During Arcobacter Butzleri Infection of Gnotobiotic Il-10 Deficient Mice

    PubMed Central

    Gölz1, Greta; Alter, Thomas; Bereswill, Stefan; Heimesaat, Markus M.

    2016-01-01

    We have previously shown that Arcobacter butzleri infection induces Toll-like receptor (TLR) -4 dependent immune responses in perorally infected gnotobiotic IL-10–/– mice. Here, we analyzed TLR-4-dependent expression of genes encoding inflammatory mediators and matrix-degrading gelatinases MMP-2 and -9 in the small and large intestines of gnotobiotic TLR-4-deficient IL-10–/– mice that were perorally infected with A. butzleri strains CCUG 30485 or C1, of human and chicken origin, respectively. At day 6 following A. butzleri infection, colonic mucin-2 mRNA, as integral part of the intestinal mucus layer, was downregulated in the colon, but not ileum, of IL-10–/– but not TLR-4–/– IL-10–/– mice. CCUG 30485 strain-infected TLR-4-deficient IL-10–/– mice displayed less distinctly upregulated IFN-γ, IL-17A, and IL-1β mRNA levels in ileum and colon, which was also true for colonic IL-22. These changes were accompanied by upregulated colonic MMP-2 and ileal MMP-9 mRNA exclusively in IL-10–/– mice. In conclusion, TLR-4 is essentially involved in A. butzleri mediated modulation of gene expression in the intestines of gnotobiotic IL-10–/– mice. PMID:27141316

  4. Acanthamoeba infection in lungs of mice expressed by toll-like receptors (TLR2 and TLR4).

    PubMed

    Derda, Monika; Wojtkowiak-Giera, Agnieszka; Kolasa-Wołosiuk, Agnieszka; Kosik-Bogacka, Danuta; Hadaś, Edward; Jagodziński, Paweł P; Wandurska-Nowak, Elżbieta

    2016-06-01

    Toll-like receptors (TLRs) play a key role in the innate immune responses to a variety of pathogens including parasites. TLRs are among the most highly conserved in the evolution of the receptor family, localized mainly on cells of the immune system and on other cells such as lung cells. The aim of this study was to determine for the first time the expression of TLR2 and TLR4 in the lung of Acanthamoeba spp. infected mice using quantitative real-time polymerase chain reaction (Q-PCR) and immunohistochemical (IHC) staining. The Acanthamoeba spp. were isolated from a patient with Acanthamoeba keratitis (AK) (strain Ac 55) and from environmental samples of water from Malta Lake (Poznań, Poland - strain Ac 43). We observed a significantly increased level of expression of TLR2 as well as TLR4 mRNA from 2 to 30 days post Acanthamoeba infection (dpi) in the lungs of mice infected with Ac55 (KP120880) and Ac43 (KP120879) strains. According to our observations, increased TLR2 and TLR4 expression in the pneumocytes, interstitial cells and epithelial cells of the bronchial tree may suggest an important role of these receptors in protective immunity against Acanthamoeba infection in the lung. Moreover, increased levels of TLR2 and TLR4 mRNA expression in infected Acanthamoeba mice may suggest the involvement of these TLRs in the recognition of this amoeba pathogen-associated molecular pattern (PAMP).

  5. Immunostimulatory effect of salmon prolactin on expression of Toll-like receptors in Oncorhynchus mykiss infected with Piscirickettsia salmonis.

    PubMed

    Peña, B; Isla, A; Haussmann, D; Figueroa, J

    2016-04-01

    In aquaculture, antibiotics are the traditional treatment used against bacterial infections. However, their use has increasingly come into question given their effects on fish and, possibly, on human health. Consequently, there is interest in developing alternative treatments aimed at stimulating the innate immune response of fish, which is the first line of defense against pathogens. In relation to this, the Toll-like receptors (TLR) aid in the selective identification of pathogens. The present study evaluated immunostimulatory activity of prolactin (PRL) hormone on expression levels of TLR1, 9, and 22, MyD88, and IL-1β during in vitro infection with the fish pathogen Piscirickettsia salmonis, in primary cultures of Oncorhynchus mykiss head kidney cells. Results indicated that PRL increased expression of TLRs and MyD88 during the first hours of bacterial infection, while a constant increase in expression was found for IL-1β. These findings suggest that PRL indirectly modulates expression of TLRs by activating expression of suppressors of cytokine signaling, thereby regulating immune response over long periods of time during bacterial infection.

  6. Responses to Toll-like receptor ligands in children living in areas where schistosome infections are endemic.

    PubMed

    van der Kleij, Desiree; van den Biggelaar, Anita H J; Kruize, Yvonne C M; Retra, Kim; Fillie, Yvonne; Schmitz, Marion; Kremsner, Peter G; Tielens, Aloysius G M; Yazdanbakhsh, Maria

    2004-03-15

    To study the effect of repeated challenge of the innate immune system with pathogen-associated molecular patterns, cytokine responses to schistosomal lipids and bacterial lipopolysaccharide (LPS) were analyzed in schoolchildren living in an area in Gabon where schistosomiasis, a helminth infection that is chronic in nature, is endemic. A schistosomal phosphatidylserine (PS) fraction containing the Toll-like receptor (TLR)-2 ligand lyso-PS stimulated the production of interleukin (IL)-8, IL-10, IL-6, and tumor necrosis factor (TNF)-alpha in children without Schistosoma haematobium infection. However, in infected children, the responses to this stimulus were lower, in particular for production of IL-8 and TNF-alpha. Responses to the TLR4 ligand, LPS, followed a similar pattern. In contrast, schistosomal adult worm glycolipids that did not stimulate any of the TLRs tested induced IL-8 and IL-6 responses that were significantly higher in schistosome-infected children than in schistosome-uninfected children. These results indicate that relentless exposure to pathogens can lead to altered responses to TLR ligands. PMID:14999608

  7. Expression of Toll-like receptor 4 in lungs of immune-suppressed rat with Acinetobacter baumannii infection

    PubMed Central

    Wang, Yanmei; Zhang, Xiaohong; Feng, Xuanlin; Liu, Xiaoshu; Deng, Lei; Liang, Zong-An

    2016-01-01

    Toll-like receptor 4 (TLR4) is involved in the regulation of host responses to Acinetobacter baumannii (A. baumannii). The aim of the present study was to examine the function of TLR4 in lung inflammation in immune-suppressed rats with A. baumannii infection. A total of 72 Sprague-Dawley male rats were randomly divided into the control, A. baumannii infection and immune-suppressed infection groups. The immune-suppressed infection group was treated with 100 mg/kg hydrocortisone by subcutaneous injection every other day for 2 weeks prior to A. baumannii infection. Lung tissue was obtained on the 3rd and 7th day after tracheal inoculation with A. baumannii. The expression of TLR4 in bronchial and alveolar epithelial cells, and alveolar macrophage was examined using immunohistochemistry. The levels of interleukin (IL)-6, tumor necrosis factor (TNF)-α in bronchoalveolar lavage fluid were detected using ELISA. The results showed that in the control group, the expression of TLR4 was upregulated in the bronchial and alveolar epithelial, and alveolar macrophages, and the levels of IL-6 and TNF-α were increased in the early phase of A. baumannii infection. On the 7th day, no significant difference in the levels of IL-6 and TNF-α was observed between the A. baumannii infection and control groups. Conversely, the expression of TLR4 was downregulated in the immune-suppressed group, and the levels of IL-6 and TNF-α were reduced on the 3rd day after infection. In the subsequent observation period, the expression of TLR4 was upregulated and the levels of IL-6 and TNF-α were increased. In conclusion, the results show a critical role of TLR4 in mediating effective immune response in the lung of rat with A. baumannii infection. PMID:27703512

  8. Synthetic Toll-like receptor 7 ligand inhibits porcine reproductive and respiratory syndrome virus infection in primary porcine alveolar macrophages.

    PubMed

    Du, Yongkun; Du, Taofeng; Shi, Yunpeng; Zhang, Angke; Zhang, Chong; Diao, Yuwen; Jin, Guangyi; Zhou, En-Min

    2016-07-01

    Porcine reproductive and respiratory syndrome virus (PRRSV), a common viral pathogen, causes huge annual economic losses to the swine industry worldwide. After triggering by specific ligands, the Toll-like receptor 7 (TLR7), a type of pattern-recognition receptor (PRR), induces antiviral cytokines production. Previously, we synthesized an adenine analog, designated SZU101, a TLR7-specific ligand. In this study, we assessed the inhibitory effect of SZU101 on PRRSV infection in vitro. SZU101 significantly suppressed PRRSV infection in primary porcine alveolar macrophages (PAMs) in a dose-dependent manner. Moreover, SZU101-induced inhibition involved NF-κB pathway activation in PAMs to initiate expression of TLR7-mediated cytokines and induce expression of downstream signaling IFN-stimulated genes (ISGs). Chloroquine, a TLR7 inhibitor, and BAY 11-7082, an NF-κB inhibitor, reversed both the SZU101-induced antiviral effect and induction of cytokine genes and ISGs expression. Therefore, SZU101 antiviral effects depend at least in part on TLR7-NF-κB signaling pathway. Additionally, administration of SZU101 enhanced the humoral and cell-mediated immune responses against PRRSV antigens in mice. Given these results, SZU101 holds promise as an antiviral agent and a vaccine adjuvant to prevent PRRSV infection in pigs.

  9. Toll-like Receptors 4 and 5 Cooperatively Initiate the Innate Immune Responses to Uropathogenic Escherichia coli Infection in Mouse Epididymal Epithelial Cells.

    PubMed

    Cheng, Lijing; Chen, Qiaoyuan; Zhu, Weiwei; Wu, Han; Wang, Qing; Shi, Lili; Zhao, Xiang; Han, Daishu

    2016-03-01

    Uropathogenic Escherichia coli (UPEC) may cause epididymitis and impair male fertility. The mechanisms underlying the innate immune responses to UPEC infection in the epididymis are not fully understood. This study showed that UPEC induced innate immune responses in mouse epididymal epithelial cells (EECs) through the activation of Toll-like receptor 4 (TLR4) and TLR5. Infection with UPEC significantly induced the expression of proinflammatory cytokines, including tumor necrosis factor alpha, interleukin 6, and monocyte chemoattractant protein 1, in EECs through the activation of nuclear factor kappa B. Moreover, UPEC induced the production of type 1 interferons by EECs through the activation of interferon regulatory factor 3. The UPEC-induced innate immune responses were significantly reduced in the EECs of Tlr4 or Tlr5 knockout mice. The innate immune responses were further reduced in Tlr4 and Tlr5 double-knockout EECs. Furthermore, we demonstrated that TLR4 and TLR5 cooperatively initiated the epididymal innate immune responses to UPEC infection in vivo. The results provide novel insights into the mechanisms underlying the epididymal innate immune responses to UPEC infection.

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

    SciTech Connect

    Chi, Jing; Wang, Fang; Li, Lingyun; Feng, Dongju; Qin, Jian; Xie, Fangyi; Zhou, Feng; Chen, Yun; Wang, Jinfeng; Yao, Kun

    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, 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.

  11. Toll-Like Receptor 3 is Associated With the Risk of HCV Infection and HBV-Related Diseases

    PubMed Central

    Geng, Pei-Liang; Song, Li-Xue; An, Huaijie; Huang, Jing-Yu; Li, Sheng; Zeng, Xian-Tao

    2016-01-01

    Abstract There are inconsistent data on the association of risk of hepatitis virus infection and hepatitis virus-related diseases with the toll-like receptor 3 (TLR3) gene. Several common polymorphism sites were targeted to assess the risk of HBV infection, HCV infection, and HBV-related diseases. Meta-analysis combining data for 3547 cases and 2797 controls from 8 studies was performed in this study. Pooled ORs were calculated to measure the risk of hepatitis virus infection and hepatitis virus-related diseases. Fixed-effects pooled ORs were calculated using the Mantel-Haenszel method. The TLR3 gene was associated with a significantly increased risk of HBV-related diseases among 1355 patients and 1130 controls ([pooled OR, [95%CI]: 1.30, [1.15–1.48] for dominant; 1.77, [1.35–2.31] for recessive; 1.28 [1.16–1.41] for allele frequency). Subgroup analyses by a polymorphism site indicated an increased risk of HCV infection in relation to the TT/CT genotypes of rs3775291 (1.50 [1.11–2.01]), and a decreased risk ascribed to the T allele (0.20 [0.16–0.25]). We also noted an association between rs3775291 and significantly increased risk of HBV-related diseases (2.23 [1.55–3.21]). No significant inter-study heterogeneity or publication bias was detected in the analyses. These data suggest a likely effect on the risk to infect HCV and develop HBV-related diseases for the TLR3 gene. Large-scale studies with racially diverse populations are required to validate these findings. PMID:27227908

  12. Unexpected Roles for Toll-Like Receptor 4 and TRIF in Intraocular Infection with Gram-Positive Bacteria

    PubMed Central

    Parkunan, Salai Madhumathi; Randall, C. Blake; Coburn, Phillip S.; Astley, Roger A.; Staats, Rachel L.

    2015-01-01

    Inflammation caused by infection with Gram-positive bacteria is typically initiated by interactions with Toll-like receptor 2 (TLR2). Endophthalmitis, an infection and inflammation of the posterior segment of the eye, can lead to vision loss when initiated by a virulent microbial pathogen. Endophthalmitis caused by Bacillus cereus develops as acute inflammation with infiltrating neutrophils, and vision loss is potentially catastrophic. Residual inflammation observed during B. cereus endophthalmitis in TLR2−/− mice led us to investigate additional innate pathways that may trigger intraocular inflammation. We first hypothesized that intraocular inflammation during B. cereus endophthalmitis would be controlled by MyD88- and TRIF-mediated signaling, since MyD88 and TRIF are the major adaptor molecules for all bacterial TLRs. In MyD88−/− and TRIF−/− mice, we observed significantly less intraocular inflammation than in eyes from infected C57BL/6J mice, suggesting an important role for these TLR adaptors in B. cereus endophthalmitis. These results led to a second hypothesis, that TLR4, the only TLR that signals through both MyD88 and TRIF signaling pathways, contributed to inflammation during B. cereus endophthalmitis. Surprisingly, B. cereus-infected TLR4−/− eyes also had significantly less intraocular inflammation than infected C57BL/6J eyes, indicating an important role for TLR4 in B. cereus endophthalmitis. Taken together, our results suggest that TLR4, TRIF, and MyD88 are important components of the intraocular inflammatory response observed in experimental B. cereus endophthalmitis, identifying a novel innate immune interaction for B. cereus and for this disease. PMID:26195555

  13. Host Avian Beta-Defensin and Toll-Like Receptor Responses of Pigeons following Infection with Pigeon Paramyxovirus Type 1

    PubMed Central

    Li, Yanyan; Xu, Qianqian; Zhang, Tingting; Gao, Mengying; Wang, Qiuling; Han, Zongxi; Shao, Yuhao

    2015-01-01

    The high morbidity and mortality in pigeons caused by pigeon paramyxovirus type 1 (PPMV-1) highlights the need for new insights into the host immune response and novel treatment approaches. Host defense peptides (HDPs) are key components of the innate immune system. In this study, three novel avian β-defensins (AvBDs 2, 7, and 10) were characterized in pigeons and shown to possess direct antiviral activity against PPMV-1 in vitro. In addition, we evaluated the mRNA expression of these AvBDs and other immune-related genes in tissues of 2-month-old infected pigeons at 3 and 7 days postinfection. We observed that the expression of AvBD2 in the cecal tonsil, lungs, and proventriculus, as well as the expression of AvBD10 in the spleen, lungs, proventriculus, and kidneys, was upregulated in infected pigeons. Similarly, the expression of both Toll-like receptor 3 (TLR3) and TLR7 was increased in the spleen, trachea, and proventriculus, while TLR15 expression was increased only in the lungs of infected pigeons. In addition, inducible nitric oxide synthase (iNOS) expression was upregulated in the spleen, the bursa of Fabricius, the trachea, and the proventriculus of infected pigeons. Furthermore, we observed a high correlation between the expression of AvBD2 and the expression of either TLR7 or TLR15, as well as between AvBD10 expression and either TLR3 or TLR7 expression in respective tissues. The results suggest that PPMV-1 infection can induce innate host responses characterized by the activation of TLRs, particularly TLR3 and TLR7, AvBDs (2 and 10), and iNOS in pigeons. PMID:26162868

  14. Host Avian Beta-Defensin and Toll-Like Receptor Responses of Pigeons following Infection with Pigeon Paramyxovirus Type 1.

    PubMed

    Li, Yanyan; Xu, Qianqian; Zhang, Tingting; Gao, Mengying; Wang, Qiuling; Han, Zongxi; Shao, Yuhao; Ma, Deying; Liu, Shengwang

    2015-09-01

    The high morbidity and mortality in pigeons caused by pigeon paramyxovirus type 1 (PPMV-1) highlights the need for new insights into the host immune response and novel treatment approaches. Host defense peptides (HDPs) are key components of the innate immune system. In this study, three novel avian β-defensins (AvBDs 2, 7, and 10) were characterized in pigeons and shown to possess direct antiviral activity against PPMV-1 in vitro. In addition, we evaluated the mRNA expression of these AvBDs and other immune-related genes in tissues of 2-month-old infected pigeons at 3 and 7 days postinfection. We observed that the expression of AvBD2 in the cecal tonsil, lungs, and proventriculus, as well as the expression of AvBD10 in the spleen, lungs, proventriculus, and kidneys, was upregulated in infected pigeons. Similarly, the expression of both Toll-like receptor 3 (TLR3) and TLR7 was increased in the spleen, trachea, and proventriculus, while TLR15 expression was increased only in the lungs of infected pigeons. In addition, inducible nitric oxide synthase (iNOS) expression was upregulated in the spleen, the bursa of Fabricius, the trachea, and the proventriculus of infected pigeons. Furthermore, we observed a high correlation between the expression of AvBD2 and the expression of either TLR7 or TLR15, as well as between AvBD10 expression and either TLR3 or TLR7 expression in respective tissues. The results suggest that PPMV-1 infection can induce innate host responses characterized by the activation of TLRs, particularly TLR3 and TLR7, AvBDs (2 and 10), and iNOS in pigeons.

  15. Global Footprints of Purifying Selection on Toll-Like Receptor Genes Primarily Associated with Response to Bacterial Infections in Humans

    PubMed Central

    Mukherjee, Souvik; Ganguli, Debdutta; Majumder, Partha P.

    2014-01-01

    Toll-like receptors (TLRs) are directly involved in host–pathogen interactions. Polymorphisms in these genes are associated with susceptibility to infectious diseases. To understand the influence of environment and pathogen diversity on the evolution of TLR genes, we have undertaken a large-scale population-genetic study. Our study included two hunter–gatherer tribal populations and one urbanized nontribal population from India with distinct ethnicities (n = 266) and 14 populations inhabiting four different continents (n = 1,092). From the data on DNA sequences of cell-surface TLR genes, we observed an excess of rare variants and a large number of low frequency haplotypes in each gene. Nonsynonymous changes were few in every population and the commonly used statistical tests for detecting natural selection provided evidence of purifying selection. The evidence of purifying selection acting on the cell-surface TLRs of the innate immune system is not consistent with Haldane’s theory of coevolution of immunity genes, at least of innate immunity genes, with pathogens. Our study provides evidence that genes of the cell-surface TLRs, that is, TLR2 and TLR4, have been so optimized to defend the host against microbial infections that new mutations in these genes are quickly eliminated. PMID:24554585

  16. Changes in the expression of Toll-like receptors in the chicken testis during sexual maturation and Salmonella infection.

    PubMed

    Anastasiadou, M; Theodoridis, A; Avdi, M; Michailidis, G

    2011-10-01

    Rooster infertility is a major concern in the poultry industry and chicken male reproductive organs are the infectious tissues of various pathogenic microorganisms. Protection of the chicken male reproductive organs from pathogens is therefore an essential aspect of reproductive physiology. Recently Toll-like receptors (TLRs) have been identified as one of the key components of innate immunity in vertebrate species and have been reported to be expressed in the reproductive organs in various female species, including the chicken. However, mechanisms of antimicrobial protection of male reproductive organs mediated by TLRs are poorly understood. The objectives of this study were to determine the expression profile of the entire family of the ten chicken TLR genes in the chicken testis, to investigate whether sexual maturation affects their testicular mRNA abundance and to determine the changes in their expression levels in response to Salmonella enteritidis (SE) infection. RNA was extracted from the testis of healthy pre-pubertal, sexually mature and aged birds, and from sexually mature SE infected birds. RT-PCR analysis revealed that all TLRs, apart from TLR1-1 (TLR6), were expressed in the chicken testis. Quantitative real-time PCR analysis revealed that the testicular mRNA abundance of certain TLRs was developmentally regulated with respect to sexual maturation, while SE infection resulted in a significant induction of TLR2-1, 4, 5, 15 and 21 in the testis of sexually mature birds compared, to healthy birds of the same age. These findings provide strong evidence to suggest a key role of TLRs in the innate immune responses of chicken testis against Salmonella colonization. PMID:21975303

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

    PubMed

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

    2014-05-01

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

  18. Viral and host factors induce macrophage activation and loss of Toll Like Receptor tolerance in chronic HCV infection

    PubMed Central

    Dolganiuc, Angela; Norkina, Oxana; Kodys, Karen; Catalano, Donna; Bakis, Gennadiy; Marshall, Christopher; Mandrekar, Pranoti; Szabo, Gyongyi

    2007-01-01

    Background&Aims Persistent inflammation contributes to progression of liver damage in chronic HCV (cHCV) infection. Repeated exposure to Toll like receptor (TLR) ligands results in tolerance, a protective mechanism aimed at limiting inflammation. Methods Monocytes/macrophages were repeatedly stimulated via pro-inflammatory cytokine-inducing TLRs and evaluated for activation markers. Results Unlike monocytes (Mo) of controls or patients with non-alcoholic steatohepatitis, the Mo of cHCV patients were hyper-responsive and failed to show homo- or hetero-tolerance to TLR ligands, manifested by elevated TNFα production. Serum levels of IFNγ, endotoxin (TLR4 ligand) and HCV core protein (TLR2 ligand) were elevated in cHCV patients suggesting potential mechanisms for in vivo monocyte pre-activation. Treatment of normal monocytes with IFNγ resulted in loss of tolerance to LPS or HCV core protein. Further, we found increased levels of MyD88-IRAK1 complexes and NFκB activity both in monocytes of cHCV patients and in normal monocytes that lost TLR tolerance after IFNγ+LPS pretreatment. In vitro differentiation of TLR tolerant cHCV monocytes into macrophages restored their capacity to exhibit TLR tolerance to LPS and HCV core protein and this could be reversed by administration of IFNγ. cHCV patients exhibited increased TNFα in the circulation and in the liver. In cHCV livers we found Kupffer cell/macrophage activation indicated by increased CD163 and CD33 expression. Conclusions We identified that host-derived factors (IFNγ and endotoxin) and viral factors (HCV core protein) act in tandem to induce and maintain monocyte/macrophage activation, thus favoring persistent inflammation in patients with cHCV infection. PMID:17916356

  19. Administration of a Toll-like receptor 9 agonist decreases the proviral reservoir in virologically suppressed HIV-infected patients.

    PubMed

    Winckelmann, Anni A; Munk-Petersen, Lærke V; Rasmussen, Thomas A; Melchjorsen, Jesper; Hjelholt, Thomas J; Montefiori, David; Østergaard, Lars; Søgaard, Ole S; Tolstrup, Martin

    2013-01-01

    Toll-like receptor (TLR) agonists can reactivate HIV from latently infected cells in vitro. We aimed to investigate the TLR-9 agonist, CPG 7909's in vivo effect on the proviral HIV reservoir and HIV-specific immunity. This was a post-hoc analysis of a double-blind randomized controlled vaccine trial. HIV-infected adults were randomized 1:1 to receive pneumococcal vaccines with or without 1 mg CPG 7909 as adjuvant at 0, 3 and 9 months. In patients on suppressive antiretroviral therapy we quantified proviral DNA at 0, 3, 4, 9, and 10 months (31 subjects in the CPG group and 37 in the placebo-adjuvant group). Furthermore, we measured HIV-specific antibodies, characterized T cell phenotypes and HIV-specific T cell immunity. We observed a mean reduction in proviral DNA in the CPG group of 12.6% (95% CI: -23.6-0.0) following each immunization whereas proviral DNA in the placebo-adjuvant group remained largely unchanged (6.7% increase; 95% CI: -4.2-19.0 after each immunization, p = 0.02). Among participants with additional cryo-preserved PBMCs, HIV-specific CD8+ T cell immunity as indicated by increased expression of degranulation marker CD107a and macrophage inflammatory protein 1β (MIP1β) tended to be up-regulated following immunization with CPG 7909 compared with placebo as adjuvant. Further, increasing proportion of HIV-specific CD107a and MIP1β-expressing CD8+ T cells were strongly correlated with decreasing proviral load. No changes were observed in T cell phenotype distribution, HIV-specific CD4+ T cell immunity, or HIV-specific antibodies. TLR9-adjuvanted pneumococcal vaccination decreased proviral load. Reductions in proviral load correlated with increasing levels of HIV specific CD8+ T cells. Further investigation into the potential effect of TLR9 agonists on HIV latency is warranted. PMID:23637967

  20. Patency of Litomosoides sigmodontis infection depends on Toll-like receptor 4 whereas Toll-like receptor 2 signalling influences filarial-specific CD4(+) T-cell responses.

    PubMed

    Rodrigo, Maria B; Schulz, Sandy; Krupp, Vanessa; Ritter, Manuel; Wiszniewsky, Katharina; Arndts, Kathrin; Tamadaho, Ruth S E; Endl, Elmar; Hoerauf, Achim; Layland, Laura E

    2016-04-01

    BALB/c mice develop a patent state [release of microfilariae (Mf), the transmission life-stage, into the periphery] when exposed to the rodent filariae Litomosoides sigmodontis. Interestingly, only a portion of the infected mice become patent, which reflects the situation in human individuals infected with Wuchereria bancrofti. Since those individuals had differing filarial-specific profiles, this study compared differences in immune responses between Mf(+) and Mf(-) infected BALB/c mice. We demonstrate that cultures of total spleen or mediastinal lymph node cells from Mf(+) mice produce significantly more interleukin-5 (IL-5) to filarial antigens but equal levels of IL-10 when compared with Mf(-) mice. However, isolated CD4(+) T cells from Mf(+) mice produced significantly higher amounts of all measured cytokines, including IL-10, when compared with CD4(+) T-cell responses from Mf(-) mice. Since adaptive immune responses are influenced by triggering the innate immune system we further studied the immune profiles and parasitology in infected Toll-like receptor-2-deficient (TLR2(-/-)) and TLR4(-/-) BALB/c mice. Ninety-three per cent of L. sigmodontis-exposed TLR4(-/-) BALB/c mice became patent (Mf(+)) although worm numbers remained comparable to those in Mf(+) wild-type controls. Lack of TLR2 had no influence on patency outcome or worm burden but infected Mf(+) mice had significantly lower numbers of Foxp3(+) regulatory T cells and dampened peripheral immune responses. Interestingly, in vitro culturing of CD4(+) T cells from infected wild-type mice with granulocyte-macrophage colony-stimulating factor-derived TLR2(-/-) dendritic cells resulted in an overall diminished cytokine profile to filarial antigens. Hence, triggering TLR4 or TLR2 during chronic filarial infection has a significant impact on patency and efficient CD4(+) T-cell responses, respectively. PMID:26714796

  1. Patency of Litomosoides sigmodontis infection depends on Toll-like receptor 4 whereas Toll-like receptor 2 signalling influences filarial-specific CD4(+) T-cell responses.

    PubMed

    Rodrigo, Maria B; Schulz, Sandy; Krupp, Vanessa; Ritter, Manuel; Wiszniewsky, Katharina; Arndts, Kathrin; Tamadaho, Ruth S E; Endl, Elmar; Hoerauf, Achim; Layland, Laura E

    2016-04-01

    BALB/c mice develop a patent state [release of microfilariae (Mf), the transmission life-stage, into the periphery] when exposed to the rodent filariae Litomosoides sigmodontis. Interestingly, only a portion of the infected mice become patent, which reflects the situation in human individuals infected with Wuchereria bancrofti. Since those individuals had differing filarial-specific profiles, this study compared differences in immune responses between Mf(+) and Mf(-) infected BALB/c mice. We demonstrate that cultures of total spleen or mediastinal lymph node cells from Mf(+) mice produce significantly more interleukin-5 (IL-5) to filarial antigens but equal levels of IL-10 when compared with Mf(-) mice. However, isolated CD4(+) T cells from Mf(+) mice produced significantly higher amounts of all measured cytokines, including IL-10, when compared with CD4(+) T-cell responses from Mf(-) mice. Since adaptive immune responses are influenced by triggering the innate immune system we further studied the immune profiles and parasitology in infected Toll-like receptor-2-deficient (TLR2(-/-)) and TLR4(-/-) BALB/c mice. Ninety-three per cent of L. sigmodontis-exposed TLR4(-/-) BALB/c mice became patent (Mf(+)) although worm numbers remained comparable to those in Mf(+) wild-type controls. Lack of TLR2 had no influence on patency outcome or worm burden but infected Mf(+) mice had significantly lower numbers of Foxp3(+) regulatory T cells and dampened peripheral immune responses. Interestingly, in vitro culturing of CD4(+) T cells from infected wild-type mice with granulocyte-macrophage colony-stimulating factor-derived TLR2(-/-) dendritic cells resulted in an overall diminished cytokine profile to filarial antigens. Hence, triggering TLR4 or TLR2 during chronic filarial infection has a significant impact on patency and efficient CD4(+) T-cell responses, respectively.

  2. Toll-Like Receptor-Triggered Calcium Mobilization Protects Mice against Bacterial Infection through Extracellular ATP Release

    PubMed Central

    Ren, Hua; Teng, Yunfei; Tan, Binghe; Zhang, Xiaoyu; Jiang, Wei; Liu, Mingyao; Jiang, Wenzheng

    2014-01-01

    Extracellular ATP (eATP), released as a “danger signal” by injured or stressed cells, plays an important role in the regulation of immune responses, but the relationship between ATP release and innate immune responses is still uncertain. In this study, we demonstrated that ATP was released through Toll-like receptor (TLR)-associated signaling in both Escherichia coli-infected mice and lipopolysaccharide (LPS)- or Pam3CSK4-treated macrophages. This ATP release could be blocked completely only by N-ethylmaleimide (NEM), not by carbenoxolone (CBX), flufenamic acid (FFA), or probenecid, suggesting the key role of exocytosis in this process. Furthermore, LPS-induced ATP release could also be reduced dramatically through suppressing calcium mobilization by use of U73122, caffeine, and thapsigargin (TG). In addition, the secretion of interleukin-1β (IL-1β) and CCL-2 was enhanced significantly by ATP, in a time- and dose-dependent manner. Meanwhile, macrophage-mediated phagocytosis of bacteria was also promoted significantly by ATP stimulation. Furthermore, extracellular ATP reduced the number of invading bacteria and protected mice from peritonitis by activating purinergic receptors. Mechanistically, phosphorylation of AKT and ERK was overtly increased by ATP in antibacterial immune responses. Accordingly, if we blocked the P2X- and P2Y-associated signaling pathway by using suramin and pyridoxal phosphate-6-azo(benzene-2,4-disulfonic acid), tetrasodium salt (PPADS), the ATP-enhanced immune response was restrained significantly. Taken together, our findings reveal an internal relationship between danger signals and TLR signaling in innate immune responses, which suggests a potential therapeutic significance of calcium mobilization-mediated ATP release in infectious diseases. PMID:25245808

  3. Polymorphisms in RNA sensing toll like receptor genes and its association with clinical outcomes of dengue virus infection.

    PubMed

    Alagarasu, K; Bachal, R V; Memane, R S; Shah, P S; Cecilia, D

    2015-01-01

    Functional polymorphisms in RNA recognizing toll like receptors (TLR) 3, 7, 8 and toll-interleukin-1 receptor domain containing adapter protein adapter (TIRAP) coding genes were investigated in 120 dengue cases [87 dengue fever (DF) cases and 33 dengue hemorrhagic fever (DHF) cases] and 109 healthy controls (HC) to identify their association with clinical outcomes of dengue virus infection. Results revealed significantly lower frequency of TLR3 rs3775291 T allele [DHF vs. DF P = 0.015 odds ratio (OR) with 95% confidence interval (CI) 0.390 (0.160–0.880); DHF vs. HC P = 0.018 OR with 95% CI 0.410 (0.170–0.900)] and ‘T’ allele carriers [DHF vs. DF P = 0.008 OR with 95% CI 0.288 (0.115–0.722); DHF vs. HC P = 0.040 OR with 95% CI 0.393 (0.162–0.956)] and higher frequency of TIRAP rs8177374 ‘C/T’ genotype [DHF vs. HC P = 0.020 OR with 95% CI 2.643 (1.167–5.986)] in DHF. Higher frequency of TLR8 rs3764879–rs3764880 haplotype C-A was observed in male DF cases compared to male HC [P = 0.025 OR with 95% CI 2.185 (1.101–4.336)]. The results suggest that TLR3 and TIRAP gene variants influence the risk for DHF.

  4. Dysregulation of Toll-Like Receptor 7 Compromises Innate and Adaptive T Cell Responses and Host Resistance to an Attenuated West Nile Virus Infection in Old Mice

    PubMed Central

    Xie, Guorui; Luo, Huanle; Pang, Lan; Peng, Bi-hung; Winkelmann, Evandro; McGruder, Brenna; Hesse, Joseph; Whiteman, Melissa; Campbell, Gerald; Milligan, Gregg N.; Cong, Yingzi; Barrett, Alan D.

    2015-01-01

    ABSTRACT The elderly are known to have enhanced susceptibility to infections and an impaired capacity to respond to vaccination. West Nile virus (WNV), a mosquito-borne flavivirus, has induced severe neurological symptoms, mostly in the elderly population. No vaccines are available for human use. Recent work showed that an attenuated WNV, a nonstructural (NS) 4B-P38G mutant, induced no lethality but strong immune responses in young (6- to 10-week-old) mice. While studying protective efficacy, we found unexpectedly that old (21- to 22-month) mice were susceptible to WNV NS4B-P38G mutant infection but were protected from subsequent lethal wild-type WNV challenge. Compared to responses in young mice, the NS4B-P38G mutant triggered higher inflammatory cytokine and interleukin-10 (IL-10) production, a delayed γδ T cell expansion, and lower antibody and WNV-specific T cell responses in old mice. Toll-like receptor 7 (TLR7) is expressed on multiple types of cells. Impaired TLR7 signaling in old mice led to dendritic cell (DC) antigen-presenting function compromise and a reduced γδ T cell and regulatory T cell (Treg) expansion during NS4B-P38G mutant infection. R848, a TLR7 agonist, decreased host vulnerability in NS4B-P38G-infected old mice by enhancing γδ T cell and Treg expansion and the antigen-presenting capacity of DCs, thereby promoting T cell responses. In summary, our results suggest that dysregulation of TLR7 partially contributes to impaired innate and adaptive T cell responses and an enhanced vulnerability in old mice during WNV NS4B-P38G mutant infection. R848 increases the safety and efficacy during immunization of old mice with the WNV NS4B-P38G mutant. IMPORTANCE The elderly are known to have enhanced susceptibility to infections and an impaired capacity to respond to vaccination. West Nile virus (WNV), an emerging mosquito-borne flavivirus, has induced severe neurological symptoms more frequently in the elderly population. No vaccines are available

  5. Gedunin Binds to Myeloid Differentiation Protein 2 and Impairs Lipopolysaccharide-Induced Toll-Like Receptor 4 Signaling in Macrophages.

    PubMed

    Borges, Perla Villani; Moret, Katelim Hottz; Maya-Monteiro, Clarissa Menezes; Souza-Silva, Franklin; Alves, Carlos Roberto; Batista, Paulo Ricardo; Caffarena, Ernesto Raúl; Pacheco, Patrícia; Henriques, Maria das Graças; Penido, Carmen

    2015-11-01

    Recognition of bacterial lipopolysaccharide (LPS) by innate immune system is mediated by the cluster of differentiation 14/Toll-like receptor 4/myeloid differentiation protein 2 (MD-2) complex. In this study, we investigated the modulatory effect of gedunin, a limonoid from species of the Meliaceae family described as a heat shock protein Hsp90 inhibitor, on LPS-induced response in immortalized murine macrophages. The pretreatment of wild-type (WT) macrophages with gedunin (0.01-100 µM, noncytotoxic concentrations) inhibited LPS (50 ng/ml)-induced calcium influx, tumor necrosis factor-α, and nitric oxide production in a concentration-dependent manner. The selective effect of gedunin on MyD88-adapter-like/myeloid differentiation primary response 88- and TRIF-related adaptor molecule/TIR domain-containing adapter-inducing interferon-β-dependent signaling pathways was further investigated. The pretreatment of WT, TIR domain-containing adapter-inducing interferon-β knockout, and MyD88 adapter-like knockout macrophages with gedunin (10 µM) significantly inhibited LPS (50 ng/ml)-induced tumor necrosis factor-α and interleukin-6 production, at 6 hours and 24 hours, suggesting that gedunin modulates a common event between both signaling pathways. Furthermore, gedunin (10 µM) inhibited LPS-induced prostaglandin E2 production, cyclooxygenase-2 expression, and nuclear factor κB translocation into the nucleus of WT macrophages, demonstrating a wide-range effect of this chemical compound. In addition to the ability to inhibit LPS-induced proinflammatory mediators, gedunin also triggered anti-inflammatory factors interleukin-10, heme oxygenase-1, and Hsp70 in macrophages stimulated or not with LPS. In silico modeling studies revealed that gedunin efficiently docked into the MD-2 LPS binding site, a phenomenon further confirmed by surface plasmon resonance. Our results reveal that, in addition to Hsp90 modulation, gedunin acts as a competitive inhibitor of LPS, blocking

  6. Antagonist-mediated down-regulation of toll-like receptors increases the prevalence of human papillomavirus infection in systemic lupus erythematosus

    PubMed Central

    2012-01-01

    Introduction Prevalence of an abnormal Papanicolaou smear was significantly increased in lupus patients in cross-sectional studies, associated with a higher prevalence of high-risk human papillomavirus (HPV) infection. The nucleic acid-specific Toll-like receptors (TLRs) locate at the endolysosomal compartments and trigger the induction of cytokines for the innate immune response. This study evaluated whether abnormal host innate immune response in lupus patients may enhance HPV persistence. Methods Protein levels of TLRs 3, 7, 8 and 9 in cervical epithelial cells of lupus patients and controls with or without HPV infection were assessed using flow cytometry. Characteristics associated with the differential expression of TLRs in systemic lupus erythematosus (SLE) were elucidated. The effect and interferon-stimulated genes (ISGs) (ISG15 and Mx-1) gene expressions were then measured in oncogenic HeLa (HPV18), CaSki (HPV) and C33A (HPV negative) cell lines using flow cytometry and quantitative real-time PCR. Ex vivo productions of cytokines and interferon-gamma (IFN-γ) upon TLR ligands stimulations were subsequently measured using cytometric bead array and ELISA. Results For subjects with HPV infection, levels of TLR3 and TLR7 were significantly lower in lupus patients compared with controls. Significantly decreased TLRs 7, 8 and 9 levels were observed in HPV-negative SLE compared to healthy controls. For SLE with and without HPV infection, TLR7 and 9 levels were significantly lower in infected SLE than those in HPV-negative patients. Independent explanatory variables associated with down-regulation of TLR7 level included HPV infection and a higher cumulative dose of prednisolone; while a higher cumulative dose of hydroxychloroquine and HPV infection were associated with down-regulation of TLR9 level. In cervical cell lines, TLRs 3, 7, 8, 9 protein levels and antiviral ISG15 and Mx-1 gene expressions were inhibited in two oncogenic HPV types. Functional data showed

  7. A Temporal Gate for Viral Enhancers to Co-opt Toll-Like-Receptor Transcriptional Activation Pathways upon Acute Infection

    PubMed Central

    Kropp, Kai A.; Hsieh, Wei Yuan; Isern, Elena; Forster, Thorsten; Krause, Eva; Brune, Wolfram; Angulo, Ana; Ghazal, Peter

    2015-01-01

    Viral engagement with macrophages activates Toll-Like-Receptors (TLRs) and viruses must contend with the ensuing inflammatory responses to successfully complete their replication cycle. To date, known counter-strategies involve the use of viral-encoded proteins that often employ mimicry mechanisms to block or redirect the host response to benefit the virus. Whether viral regulatory DNA sequences provide an opportunistic strategy by which viral enhancer elements functionally mimic innate immune enhancers is unknown. Here we find that host innate immune genes and the prototypical viral enhancer of cytomegalovirus (CMV) have comparable expression kinetics, and positively respond to common TLR agonists. In macrophages but not fibroblasts we show that activation of NFκB at immediate-early times of infection is independent of virion-associated protein, M45. We find upon virus infection or transfection of viral genomic DNA the TLR-agonist treatment results in significant enhancement of the virus transcription-replication cycle. In macrophage time-course infection experiments we demonstrate that TLR-agonist stimulation of the viral enhancer and replication cycle is strictly delimited by a temporal gate with a determined half-maximal time for enhancer-activation of 6 h; after which TLR-activation blocks the viral transcription-replication cycle. By performing a systematic siRNA screen of 149 innate immune regulatory factors we identify not only anticipated anti-viral and pro-viral contributions but also new factors involved in the CMV transcription-replication cycle. We identify a central convergent NFκB-SP1-RXR-IRF axis downstream of TLR-signalling. Activation of the RXR component potentiated direct and indirect TLR-induced activation of CMV transcription-replication cycle; whereas chromatin binding experiments using wild-type and enhancer-deletion virus revealed IRF3 and 5 as new pro-viral host transcription factor interactions with the CMV enhancer in macrophages. In a

  8. Toll-like receptor 4 is involved in the cell cycle modulation and required for effective human cytomegalovirus infection in THP-1 macrophages

    SciTech Connect

    Arcangeletti, Maria-Cristina; Germini, Diego; Rodighiero, Isabella; Mirandola, Prisco; De Conto, Flora; Medici, Maria-Cristina; Gatti, Rita; Chezzi, Carlo; Calderaro, Adriana

    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 promoting 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.

  9. Proinflammatory Stimulation of Toll-Like Receptor 9 with High Dose CpG ODN 1826 Impairs Endothelial Regeneration and Promotes Atherosclerosis in Mice

    PubMed Central

    Steinmetz, Martin; Asdonk, Tobias; Lahrmann, Catharina; Lütjohann, Dieter; Nickenig, Georg; Zimmer, Sebastian

    2016-01-01

    Background Toll-like receptors (TLR) of the innate immune system have been closely linked with the development of atherosclerotic lesions. TLR9 is activated by unmethylated CpG motifs within ssDNA, but also by CpG motifs in nucleic acids released during vascular apoptosis and necrosis. The role of TLR9 in vascular disease remains controversial and we sought to investigate the effects of a proinflammatory TLR9 stimulation in mice. Methods and Findings TLR9-stimulation with high dose CpG ODN at concentrations between 6.25nM to 30nM induced a significant proinflammatory cytokine response in mice. This was associated with impaired reendothelialization upon acute denudation of the carotid and increased numbers of circulating endothelial microparticles, as a marker for amplified endothelial damage. Chronic TLR9 agonism in apolipoprotein E-deficient (ApoE-/-) mice fed a cholesterol-rich diet increased aortic production of reactive oxygen species, the number of circulating endothelial microparticles, circulating sca-1/flk-1 positive cells, and most importantly augmented atherosclerotic plaque formation when compared to vehicle treated animals. Importantly, high concentrations of CpG ODN are required for these proatherogenic effects. Conclusions Systemic stimulation of TLR9 with high dose CpG ODN impaired reendothelialization upon acute vascular injury and increased atherosclerotic plaque development in ApoE-/- mice. Further studies are necessary to fully decipher the contradictory finding of TLR9 agonism in vascular biology. PMID:26751387

  10. [Toll-like receptors expression in the lungs of human metapneumovirus infected mice and the effects of polyI:C on viral infection].

    PubMed

    Dou, Ying; Zhao, Yao; Zhang, Zhi-Yong; Zhao, Xiao-Dong

    2010-01-01

    To investigate the expression changes of Toll-like receptors (TLR) in the lungs of human metapneumovirus infected BALB/c mice, and to explore the effects of PolyI:C on viral replication, HMPV-infected group, PolyI:C+hMPV group, PolyI:C+DMED group and DMEM control group were set up for this study. All mice were sacrificed on day 1, 3, 5, 7, 9 and 16 post inoculation. Lungs were used for viral titration, pulmonary histopathology and detection of TLRs mRNA expression by RT-PCR and real-time PCR. Results showed that the levels of viral replication in the lungs of PolyI:C+hMPV infected mice were significantly decreased and lung inflammation were also lessened compared with those of hMPV infected mice. RT-PCR detection showed that mRNA levels of most TLRs were up-regulated (P < 0.05) in the lungs of hMPV infected group compared with DMEM group. Real time PCR assay showed that TLR7-8 mRNA significantly increased in hMPV infected group in a time-dependent manner. The level of TLR3 mRNA was significantly up-regulated in PolyI:C+hMPV group at the 24 hour after intranasal inoculation. The results showed that hMPV infection up-regulated the expression of TLRs in lungs of BALB/c mice and TLR7/8 pathway might play an important role in the start of natural immune response. PolyI:C was capable of inhibiting viral replication in the lung of mice and reducing lung inflammation probably through the early activation of TLR3.

  11. Molecular cloning, characterization and expression analysis of Toll-like receptor 5M gene in Japanese sea perch (Lateolabrax japonicas) after bacterial infection.

    PubMed

    Wang, Chengyang; Zhao, Chao; Fu, Mingjun; Bao, Weiyang; Qiu, Lihua

    2016-09-01

    Toll-like receptor 5M belongs to Toll-like receptors (TLRs) family, which plays a crucial role in innate immunity due to its important role in the recognition of bacteria invasion and in the activation of immune related pathways downstream. In the present study, we firstly cloned the full-length cDNAs of TLR 5M (LjTLR 5M) from Japanese sea perch (Lateolabrax japonicas). The full-length cDNAs of LjTLR 5M include an open reading frame (ORF) of 2676 bp encoding a polypeptide of 891 amino acid residues. The deduced amino acid sequence analysis showed that LiTLR 5M contains LRRs (extracellular leucine rich repeats), transmembrane and TIR (Toll/interleukin-1 receptor) domain. Transcriptional expression analysis indicated that LiTLR 5M mRNAs were ubiquitously expressed in wide array of tissues and the peak level was observed in the head-kidney. The expression patterns of LjTLR 5M after Vibro harveyi and Streptococus agalactiae infection were detected by qRT-PCR, and the results showed that LjTLR 5M was significant up-regulated in spleen, liver and head-kidney. Additionally, the expression patterns of LjTLR 5M in infected spleen and head-kidney were further validated by in situ hybridization (ISH). In summary, these findings indicate that LjTLR 5M is significant induced after different bacterial infection and is involved in immune response. Furthermore, this study will provide foundational information for other TLRs research of L. japonicas against different bacterial pathogens invasion. PMID:27417233

  12. Molecular cloning, characterization and expression analysis of Toll-like receptor 5M gene in Japanese sea perch (Lateolabrax japonicas) after bacterial infection.

    PubMed

    Wang, Chengyang; Zhao, Chao; Fu, Mingjun; Bao, Weiyang; Qiu, Lihua

    2016-09-01

    Toll-like receptor 5M belongs to Toll-like receptors (TLRs) family, which plays a crucial role in innate immunity due to its important role in the recognition of bacteria invasion and in the activation of immune related pathways downstream. In the present study, we firstly cloned the full-length cDNAs of TLR 5M (LjTLR 5M) from Japanese sea perch (Lateolabrax japonicas). The full-length cDNAs of LjTLR 5M include an open reading frame (ORF) of 2676 bp encoding a polypeptide of 891 amino acid residues. The deduced amino acid sequence analysis showed that LiTLR 5M contains LRRs (extracellular leucine rich repeats), transmembrane and TIR (Toll/interleukin-1 receptor) domain. Transcriptional expression analysis indicated that LiTLR 5M mRNAs were ubiquitously expressed in wide array of tissues and the peak level was observed in the head-kidney. The expression patterns of LjTLR 5M after Vibro harveyi and Streptococus agalactiae infection were detected by qRT-PCR, and the results showed that LjTLR 5M was significant up-regulated in spleen, liver and head-kidney. Additionally, the expression patterns of LjTLR 5M in infected spleen and head-kidney were further validated by in situ hybridization (ISH). In summary, these findings indicate that LjTLR 5M is significant induced after different bacterial infection and is involved in immune response. Furthermore, this study will provide foundational information for other TLRs research of L. japonicas against different bacterial pathogens invasion.

  13. Genetic variability in swine leukocyte antigen class II and Toll-like receptors affects immune responses to vaccination for bacterial infections in pigs.

    PubMed

    Shinkai, H; Arakawa, A; Tanaka-Matsuda, M; Ide-Okumura, H; Terada, K; Chikyu, M; Kawarasaki, T; Ando, A; Uenishi, H

    2012-12-01

    The genes encoding swine leukocyte antigen (SLA) and Toll-like receptor (TLR) are highly polymorphic in pig populations, and likely have influences on infection and the effects of vaccination. We explored the associations of different genotypes of SLA class II and of the genes TLR1, TLR4, TLR5, and TLR6 with antibody responses after vaccination against Erysipelothrix rhusiopathiae (ER) and Actinobacillus pleuropneumoniae (APP) serotypes 1, 2, and 5 in 191 Duroc pigs maintained under specific pathogen-free conditions. We demonstrated close relationships between SLA class II and ER antibody response and between TLR genes other than TLR4 and APP antibody responses. Pigs with specific haplotypes in SLA class II or TLR5 showed decreased antibody response to ER vaccination or increased responses to APP2 and APP5 vaccination, respectively. It might be possible to breed for responsiveness to vaccination and to implement new vaccine development strategies unaffected by genetic backgrounds of pigs.

  14. 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. PMID:27033908

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

    PubMed Central

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

    2016-01-01

    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. PMID:27550658

  16. 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

    2016-01-01

    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. PMID:27550658

  17. 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.

  18. Toll-like receptor of mud crab, Scylla serrata: molecular characterisation, ontogeny and functional expression analysis following ligand exposure, and bacterial and viral infections.

    PubMed

    Vidya, R; Paria, Anutosh; Deepika, A; Sreedharan, K; Makesh, M; Purushothaman, C S; Chaudhari, Aparna; Gireesh Babu, P; Rajendran, K V

    2014-10-01

    Toll-like receptors are sentinels of innate immune system, which recognise pathogen-associated molecular patterns, and subsequently activate production of antimicrobial peptides to contain the infection. In the present study, we cloned and characterised a Toll gene from Scylla serrata (SsToll) encoding 1005 amino acids with typical Toll-like receptor domain topology. Phylogenetic analysis revealed that it belongs to insect-type invertebrate Toll family showing 100 % identity with Scylla paramamosain (SpToll). The expression pattern of mRNA in different tissues indicated that SsToll is constitutively expressed in all the tissues examined, with varying expression levels. The expression was also detected in all the life-stages (egg, zoea stages 1-5, megalopa and crab instar) with the highest level observed in zoea 2. In-vitro studies using crab haemocyte culture demonstrated that SsToll transcripts are distinctly modulated in response to ligands such as peptidoglycan and lipopolysaccharide at all time-points. A significant change in SsToll expression was also noticed in haemocytes exposed to poly I:C (3-9 h). On the contrary, the transcription level of SsToll in response to white spot syndrome virus (WSSV) challenge was noticeably different. The change in expression in vitro was not significant at early time-points until 3 h; the transcripts showed a significant up-regulation commencing from 6 h, but not beyond 12 h. However, in vivo expression was unaffected at early time-points of WSSV challenge (until 12 h) and a gradual up-regulation was detected at 24 h. In-vivo challenge with Vibrio parahaemolyticus resulted in delayed up-regulation of the gene. The results obtained in the present study suggest that SsToll might be involved in the innate immunity of mud crab.

  19. Therapeutic Administration of KM+ Lectin Protects Mice Against Paracoccidioides brasiliensis Infection via Interleukin-12 Production in a Toll-Like Receptor 2-Dependent Mechanism

    PubMed Central

    Coltri, Kely C.; Oliveira, Leandro L.; Pinzan, Camila F.; Vendruscolo, Patrícia E.; Martinez, Roberto; Goldman, Maria Helena; Panunto-Castelo, Ademilson; Roque-Barreira, Maria-Cristina

    2008-01-01

    KM+ is a mannose-binding lectin from Artocarpus integrifolia that induces interleukin (IL)-12 production by macrophages and protective T helper 1 immune response against Leishmania major infection. In this study, we performed experiments to evaluate the therapeutic activity of jackfruit KM+ (jfKM+) and its recombinant counterpart (rKM+) in experimental paracoccidioidomycosis. To this end, jfKM+ or rKM+ was administered to BALB/c mice 10 days after infection with Paracoccidiodes brasiliensis. Thirty days postinfection, lungs from the KM+-treated mice contained significantly fewer colony-forming units and little to no organized granulomas compared to the controls. In addition, lung homogenates from the KM+-treated mice presented higher levels of nitric oxide, IL-12, interferon-γ, and tumor necrosis factor-α, whereas higher levels of IL-4 and IL-10 were detected in the control group. With mice deficient in IL-12, Toll-like receptor (TLR) 2, TLR4, or TLR adaptor molecule MyD88, we demonstrated that KM+ led to protection against P. brasiliensis infection through IL-12 production, which was dependent on TLR2. These results demonstrated a beneficial effect of KM+ on the severity of P. brasiliensis infection and may expand its potential use as a novel immunotherapeutic molecule. PMID:18599609

  20. Therapeutic administration of KM+ lectin protects mice against Paracoccidioides brasiliensis infection via interleukin-12 production in a toll-like receptor 2-dependent mechanism.

    PubMed

    Coltri, Kely C; Oliveira, Leandro L; Pinzan, Camila F; Vendruscolo, Patrícia E; Martinez, Roberto; Goldman, Maria Helena; Panunto-Castelo, Ademilson; Roque-Barreira, Maria-Cristina

    2008-08-01

    KM(+) is a mannose-binding lectin from Artocarpus integrifolia that induces interleukin (IL)-12 production by macrophages and protective T helper 1 immune response against Leishmania major infection. In this study, we performed experiments to evaluate the therapeutic activity of jackfruit KM(+) (jfKM(+)) and its recombinant counterpart (rKM(+)) in experimental paracoccidioidomycosis. To this end, jfKM(+) or rKM(+) was administered to BALB/c mice 10 days after infection with Paracoccidiodes brasiliensis. Thirty days postinfection, lungs from the KM(+)-treated mice contained significantly fewer colony-forming units and little to no organized granulomas compared to the controls. In addition, lung homogenates from the KM(+)-treated mice presented higher levels of nitric oxide, IL-12, interferon-gamma, and tumor necrosis factor-alpha, whereas higher levels of IL-4 and IL-10 were detected in the control group. With mice deficient in IL-12, Toll-like receptor (TLR) 2, TLR4, or TLR adaptor molecule MyD88, we demonstrated that KM(+) led to protection against P. brasiliensis infection through IL-12 production, which was dependent on TLR2. These results demonstrated a beneficial effect of KM(+) on the severity of P. brasiliensis infection and may expand its potential use as a novel immunotherapeutic molecule.

  1. Toll like receptor 2 and CC chemokine receptor 5 cluster in the lipid raft enhances the susceptibility of Leishmania donovani infection in macrophages.

    PubMed

    Majumdar, Suchandra Bhattacharyya; Bhattacharya, Parna; Bhattacharjee, Surajit; Majumder, Saikat; Banerjee, Sayantan; Majumdar, Subrata

    2014-01-01

    In experimental visceral leishmaniasis the causative obligate protozoan parasite, L. donovani invades and multiplies inside of macrophages, one of the sentries of the mammalian immune system. The initial host-parasite interaction between the Leishmania promastigote and the macrophage takes place at the plasma membrane interface. To trace any possible interaction between Toll-like receptor 2 (TLR2) and CC chemokine receptor 5 (CCR5) during early Leishmania-macrophage interactions, it was observed that the expression of both TLR2 and CCR5 were significantly increased, along with their recruitment to the lipid raft. TLR2 silencing attenuates CCR5 expression and restricts L. donovani infection, indicating a regulatory role of TLR2 and CCR5 during infection. Silencing of CCR5 and TLR2 markedly reduced the number of intracellular parasites in macrophages by host protective cytokine responses, while raft disruption using beta-MCD affected TLR2/CCR5 cross-talk and resulted in a significant reduction in parasite invasion. In vivo RNA interference of TLR2 and CCR5 using shRNA plasmids rendered protection in Leishmania donovani-infected mice. Thus, this study for the first time demonstrates the importance of TLR2/CCR5 crosstalk as a significant determinant of Leishmania donovani entry in host macrophages.

  2. Toll-Like Receptor 3 Signaling via TRIF Contributes to a Protective Innate Immune Response to Severe Acute Respiratory Syndrome Coronavirus Infection

    PubMed Central

    Totura, Allison L.; Whitmore, Alan; Agnihothram, Sudhakar; Schäfer, Alexandra; Katze, Michael G.; Heise, Mark T.

    2015-01-01

    ABSTRACT Toll-like receptors (TLRs) are sensors that recognize molecular patterns from viruses, bacteria, and fungi to initiate innate immune responses to invading pathogens. The emergence of highly pathogenic coronaviruses severe acute respiratory syndrome coronavirus (SARS-CoV) and Middle East respiratory syndrome coronavirus (MERS-CoV) is a concern for global public health, as there is a lack of efficacious vaccine platforms and antiviral therapeutic strategies. Previously, it was shown that MyD88, an adaptor protein necessary for signaling by multiple TLRs, is a required component of the innate immune response to mouse-adapted SARS-CoV infection in vivo. Here, we demonstrate that TLR3−/−, TLR4−/−, and TRAM−/− mice are more susceptible to SARS-CoV than wild-type mice but experience only transient weight loss with no mortality in response to infection. In contrast, mice deficient in the TLR3/TLR4 adaptor TRIF are highly susceptible to SARS-CoV infection, showing increased weight loss, mortality, reduced lung function, increased lung pathology, and higher viral titers. Distinct alterations in inflammation were present in TRIF−/− mice infected with SARS-CoV, including excess infiltration of neutrophils and inflammatory cell types that correlate with increased pathology of other known causes of acute respiratory distress syndrome (ARDS), including influenza virus infections. Aberrant proinflammatory cytokine, chemokine, and interferon-stimulated gene (ISG) signaling programs were also noted following infection of TRIF−/− mice that were similar to those seen in human patients with poor disease outcome following SARS-CoV or MERS-CoV infection. These findings highlight the importance of TLR adaptor signaling in generating a balanced protective innate immune response to highly pathogenic coronavirus infections. PMID:26015500

  3. The Importance of Toll-like Receptors in NF-κB Signaling Pathway Activation by Helicobacter pylori Infection and the Regulators of this Response.

    PubMed

    Hu, Yi; Liu, Jian-Ping; Zhu, Yin; Lu, Nong-Hua

    2016-10-01

    Helicobacter pylori (H. pylori) is a common pathogenic bacterium in the stomach that infects almost half of the population worldwide and is closely related to gastric diseases and some extragastric diseases, including iron-deficiency anemia and idiopathic thrombocytopenic purpura. Both the Maastricht IV/Florence consensus report and the Kyoto global consensus report have proposed the eradication of H. pylori to prevent gastric cancer as H.pylori has been shown to be a major cause of gastric carcinogenesis. The interactions between H. pylori and host receptors induce the release of the proinflammatory cytokines by activating proinflammatory signaling pathways such as nuclear factor kappa B (NF-κB), which plays a central role in inflammation, immune response, and carcinogenesis. Among these receptors, Toll-like receptors (TLRs) are classical pattern recognition receptors in the recognition of H. pylori and the mediation of the host inflammatory and immune responses to H. pylori. TLR polymorphisms also contribute to the clinical consequences of H. pylori infection. In this review, we focus on the functions of TLRs in the NF-κB signaling pathway activated by H. pylori, the regulators modulating this response, and the functions of TLR polymorphisms in H.pylori-related diseases.

  4. Toll-like receptors, IFN-γ and IL-12 expression in bovine leukemia virus-infected animals with low or high proviral load.

    PubMed

    Farias, María Victoria Nieto; Lendez, Pamela Anahí; Marin, Maia; Quintana, Silvina; Martínez-Cuesta, Lucía; Ceriani, María Carolina; Dolcini, Guillermina Laura

    2016-08-01

    Bovine leukemia virus (BLV) infection is widespread mainly in dairy cattle and 5-10% of infected animals will die due to lymphosarcoma; most cattle remain asymptomatic but 30% develop persistent lymphocytosis (PL). BLV transmission depends on infected cell exchange and thus, proviral load is determinant. Understanding the mechanisms which govern the control of viral dissemination will be desirable for the design of effective therapeutic or preventive strategies for BLV. The development of high proviral load (HPL) or low proviral load (LPL) might be associated to genetic factors and humoral immune responses, however cellular responses are not fully described. We aimed to characterize cytokines and toll-like receptors (TLR) expression related to the proviral load profiles. IFN-γ and IL-12 mRNA expression level was significantly higher in PBMC from infected cattle (LPL n=6 and HPL n=7) compared to uninfected animals (n=5). While no significant differences were observed in IL-12 expression between LPL and HPL group, IFN-γ expression was significantly higher in LPL animals. Infected cattle exhibited higher expression levels of TLR3, 7-9. Animals with HPL had significantly higher expression of TLR7/8 than uninfected cattle. TLR8 and TLR9 were up-regulated in HPL group, and TLR3 was up-regulated in LPL group. This is the first report related to TLR gene expression in BLV infected cattle and represents evidence of the involvement of these receptors in BLV recognition. Further studies on different subpopulations of immune cells may help clarify their role in response to BLV and its consequences on viral dissemination. PMID:27473994

  5. The Association of Toll-Like Receptor 4 Polymorphism with Hepatitis C Virus Infection in Saudi Arabian Patients

    PubMed Central

    Al-Qahtani, Ahmed A.; Al-Anazi, Mashael R.; Al-Zoghaibi, Fahad; Abdo, Ayman A.; Sanai, Faisal M.; Khan, Mohammed Q.; Al-Ashgar, Hamad I.; Al-Ahdal, Mohammed N.

    2014-01-01

    Hepatitis C virus (HCV) is a single stranded RNA virus. It affects millions of people worldwide and is considered as a leading cause of liver diseases including cirrhosis and hepatocellular carcinoma. A recent study reported that TLR4 gene polymorphisms are good prognostic predictors and are associated with protection from liver fibrosis among Caucasians. This study aims to investigate the implication of genetic polymorphisms of TLR4 gene on the HCV infection in Saudi Arabian patients. Two SNPs in the TLR4 gene, rs4986790 (A/G) and rs4986791 (C/T), were genotyped in 450 HCV patients and 600 uninfected controls. The association analysis confirmed that both SNPs showed a significant difference in their distribution between HCV-infected patients and uninfected control subjects (P < 0.0001; OR = 0.404, 95% CI = 0.281–0.581) and (P < 0.0001; OR = 0.298, 95% CI = 0.201–0.443), respectively. More importantly, haplotype analysis revealed that four haplotypes, AC, GT, GC, and AT (rs4986790, rs4986791), were significantly associated with HCV infection when compared with control subjects. One haplotype AC was more prominently found when chronic HCV-infected patients were compared with cirrhosis/HCC patients (frequency = 94.7% and P = 0.04). Both TLR4 SNPs under investigation were found to be significantly implicated with HCV-infection among Saudi Arabian population. PMID:25177689

  6. Toll-Like Receptor 9-Mediated Protection of Enterovirus 71 Infection in Mice Is Due to the Release of Danger-Associated Molecular Patterns

    PubMed Central

    Hsiao, Hung-Bo; Chou, Ai-Hsiang; Lin, Su-I; Chen, I-Hua; Lien, Shu-Pei; Liu, Chia-Chyi; Chong, Pele

    2014-01-01

    ABSTRACT Enterovirus 71 (EV71), a positive-stranded RNA virus, is the major cause of hand, foot, and mouth disease (HFMD) with severe neurological symptoms. Antiviral type I interferon (alpha/beta interferon [IFN-α/β]) responses initiated from innate receptor signaling are inhibited by EV71-encoded proteases. It is less well understood whether EV71-induced apoptosis provides a signal to activate type I interferon responses as a host defensive mechanism. In this report, we found that EV71 alone cannot activate Toll-like receptor 9 (TLR9) signaling, but supernatant from EV71-infected cells is capable of activating TLR9. We hypothesized that TLR9-activating signaling from plasmacytoid dendritic cells (pDCs) may contribute to host defense mechanisms. To test our hypothesis, Flt3 ligand-cultured DCs (Flt3L-DCs) from both wild-type (WT) and TLR9 knockout (TLR9KO) mice were infected with EV71. More viral particles were produced in TLR9KO mice than by WT mice. In contrast, alpha interferon (IFN-α), monocyte chemotactic protein 1 (MCP-1), tumor necrosis factor-alpha (TNF-α), IFN-γ, interleukin 6 (IL-6), and IL-10 levels were increased in Flt3L-DCs from WT mice infected with EV71 compared with TLR9KO mice. Seven-day-old TLR9KO mice infected with a non-mouse-adapted EV71 strain developed neurological lesion-related symptoms, including hind-limb paralysis, slowness, ataxia, and lethargy, but WT mice did not present with these symptoms. Lung, brain, small intestine, forelimb, and hind-limb tissues collected from TLR9KO mice exhibited significantly higher viral loads than equivalent tissues collected from WT mice. Histopathologic damage was observed in brain, small intestine, forelimb, and hind-limb tissues collected from TLR9KO mice infected with EV71. Our findings demonstrate that TLR9 is an important host defense molecule during EV71 infection. IMPORTANCE The host innate immune system is equipped with pattern recognition receptors (PRRs), which are useful for defending

  7. Toll like receptor (TLR)-induced differential expression of microRNAs (MiRs) promotes proper immune response against infections: a systematic review.

    PubMed

    Aalaei-andabili, Seyed Hossein; Rezaei, Nima

    2013-10-01

    Toll like receptors (TLRs) are one of the major families of pattern recognition receptors (PRRs). MicroRNAs (MiRs) are small noncoding RNAs with regulatory effects on biological process, and it has been recently shown that they can control inflammatory process and the response to an infection by modulating the function of TLRs. In this study, we designed a systematic review to clarify the reciprocal interaction between TLRs and MiRs, in order to identify possible future therapeutic targets and strategies. On the one hand, TLRs stimulation can change expression level of miRs in various ways, which can lead to modulating their effects. On the other hand, MiRs also influence the expression of TLRs and the intensity of the inflammatory reaction. We therefore conclude that the interaction between MiRs and TLRs is a key regulator of innate immune system. Investigations discovering therapeutic approaches by manipulation of miRs expression level may open a new approach for the treatment of inflammatory diseases. PMID:23850616

  8. Toll-like receptors and interferon associated immune factors responses to spring viraemia of carp virus infection in common carp (Cyprinus carpio).

    PubMed

    Wei, Xinxian; Li, Xiao Zheng; Zheng, Xiaocong; Jia, Peng; Wang, Jinjin; Yang, Xianle; Yu, Li; Shi, Xiujie; Tong, Guixiang; Liu, Hong

    2016-08-01

    Pattern recognition receptor (PRR) toll-like receptors (TLRs), antiviral agent interferon (IFN) and the effector IFN stimulated genes (ISGs) play a fundamental role in the innate immune response against viruses among all vertebrate classes. Common carp is a host for spring viraemia of carp virus (Rhabdovirus carpio, SVCV), which belong to Rhabdoviridae family. The present in-vivo experiment was conducted to investigate the expression of these innate immune factors in early phase as well as during recovery of SVCV infection by real-time quantitative reverse transcriptase polymerase chain reaction. A less lethal SVCV infection was generated in common carp (Cyprinus carpio) and was sampled at 3, 6, 12 h post infection (hpi), 1, 3, 5, 7 and 10 days post infection (dpi). At 3 hpi, the SVCV N gene was detected in all three fish and all three fish showed a relative fold increase of TLR2, TLR3 and TLR7, IFNa1, ISG15 and Vig1. Viral copies rapidly increased at 12 hpi then remained high until 5 dpi. When viral copy numbers were high, a higher expression of immune genes TLR2, TLR3, TLR7, IFNa1, IFNa2, IFNa1S, IFN regulatory factor 3 (IRF3), IRF7, interleukin 1β (IL1β), IL6, IL10, ADAR, ISG15, Mx1, PKR and Vig1 were observed. Viral copies were gradually reduced in 5 to 10 dpi fish, and also the immune response was considerably reduced but remained elevated. A high degree of correlation was observed between immune genes and viral copy number in each of the sampled fish at 12 hpi. The quick and prolonged elevated expression of the immune genes indicates their crucial role in survival of host against SVCV. PMID:27263115

  9. Expression profiles of toll-like receptors in anterior kidney of channel catfish, Ictalurus punctatus (Rafinesque), acutely infected by Edwardsiella ictaluri.

    PubMed

    Pridgeon, J W; Russo, R; Shoemaker, C A; Klesius, P H

    2010-06-01

    Using quantitative PCR (QPCR), the relative transcriptional levels of five toll-like receptors (TLR2, TLR3, TLR5, TLR20a and TLR21) were studied in the channel catfish, Ictalurus punctatus (Rafinesque), under uninfected and acutely infected conditions [1-, 2-, 4-, 6-, 12-, 24-, 36- and 48-h post-injection (hpi)]. Under uninfected conditions, the transcriptional levels of the five TLRs were significantly lower than that of 18S rRNA (P < 0.001). QPCR results also revealed that the transcriptional levels of TLR20a and TLR5 were higher than those of TLR2, TLR3 or TLR21. The transcriptional level of TLR3 was significantly lower than that of the other four TLRs (P < 0.001). However, when channel catfish were acutely infected by Edwardsiella ictaluri through intraperitoneal injection, the transcriptional levels of TLRs increased significantly (P < 0.005) at 6 hpi. Among the five TLRs studied, the transcriptional levels of TLR3, TLR5 and TLR21 were never significantly lower than under uninfected conditions (P = 0.16, 0.27 and 0.19, respectively), suggesting these three TLRs might play important roles in host defence against infection by E. ictaluri. The amount of E. ictaluri in the anterior kidney increased at 12 and 24 hpi but decreased at 36 and 48 hpi. Our results suggest that TLRs are important components in the immune system in the channel catfish, and their rapid transcriptional upregulation (within 6 hpi) in response to acute E. ictaluri infection might be important for survival from enteric septicaemia of catfish.

  10. Infection of Mast Cells with Live Streptococci Causes a Toll-Like Receptor 2- and Cell-Cell Contact-Dependent Cytokine and Chemokine Response ▿ †

    PubMed Central

    Rönnberg, Elin; Guss, Bengt; Pejler, Gunnar

    2010-01-01

    Mast cells (MCs) are strongly implicated in immunity toward bacterial infection, but the molecular mechanisms by which MCs contribute to the host response are only partially understood. We addressed this issue by examining the direct effects of a Gram-positive pathogen, Streptococcus equi, on bone marrow-derived MCs (BMMCs). Ultrastructural analysis revealed extensive formation of dilated rough endoplasmic reticulum in response to bacterial infection, indicating strong induction of protein synthesis. However, the BMMCs did not show signs of extensive degranulation, and this was supported by only slow release of histamine in response to infection. Coculture of live bacteria with BMMCs caused a profound secretion of CCL2/MCP-1, CCL7/MCP-3, CXCL2/MIP-2, CCL5/RANTES, interleukin-4 (IL-4), IL-6, IL-12, IL-13, and tumor necrosis factor alpha, as shown by antibody-based cytokine/chemokine arrays and/or enzyme-linked immunosorbent assay. In contrast, heat-inactivated bacteria caused only minimal cytokine/chemokine release. The cytokine/chemokine responses were substantially attenuated in Toll-like receptor 2-deficient BMMCs and were strongly dependent on cell-cell contacts between bacteria and BMMCs. Gene chip microarray analysis confirmed a massively upregulated expression of the genes coding for the secreted cytokines and chemokines and also identified a pronounced upregulation of numerous additional genes, including transcription factors, signaling molecules, and proteases. Together, the present study outlines MC-dependent molecular events associated with Gram-positive infection and thus provides an advancement in our understanding of how MCs may contribute to host defense toward bacterial insults. PMID:19933827

  11. Toll-Like receptor 2 (TLR2) and TLR9 play opposing roles in host innate immunity against Salmonella enterica serovar Typhimurium infection.

    PubMed

    Zhan, Renhui; Han, Qiuju; Zhang, Cai; Tian, Zhigang; Zhang, Jian

    2015-04-01

    Toll-like receptors (TLRs) are evolutionarily conserved host proteins that are essential for effective host defense against pathogens. However, recent studies suggest that some TLRs can negatively regulate immune responses. We observed here that TLR2 and TLR9 played opposite roles in regulating innate immunity against oral infection of Salmonella enterica serovar Typhimurium in mice. While TLR9-/- mice exhibited shortened survival, an increased cytokine storm, and more severe Salmonella hepatitis than wild-type (WT) mice, TLR2-/- mice exhibited the opposite phenomenon. Further studies demonstrated that TLR2 deficiency and TLR9 deficiency in macrophages both disrupted NK cell cytotoxicity against S. Typhimurium-infected macrophages by downregulating NK cell degranulation and gamma interferon (IFN-γ) production through decreased macrophage expression of the RAE-1 NKG2D ligand. But more importantly, we found that S. Typhimurium-infected TLR2-/- macrophages upregulated inducible nitric oxide synthase (iNOS) expression, resulting in a lower bacterial load than that in WT macrophages in vitro and livers in vivo as well as low proinflammatory cytokine levels. In contrast, TLR9-/- macrophages showed decreased reactive oxygen species (ROS) expression concomitant with a high bacterial load in the macrophages and in livers of TLR9-/- mice. TLR9-/- macrophages were also more susceptible than WT macrophages to S. Typhimurium-induced necroptosis in vitro, likely contributing to bacterial spread and transmission in vivo. Collectively, these findings indicate that TLR2 negatively regulates anti-S. Typhimurium immunity, whereas TLR9 is vital to host defense and survival against S. Typhimurium invasion. TLR2 antagonists or TLR9 agonists may thus serve as potential anti-S. Typhimurium therapeutic agents.

  12. Expression of avian β-defensins and Toll-like receptor genes in the rooster epididymis during growth and Salmonella infection.

    PubMed

    Anastasiadou, M; Avdi, M; Michailidis, G

    2013-08-01

    The epididymis is an organ involved in the maturation, transport, and storage of sperm prior to ejaculation. As epididymis is exposed to a constant risk of inflammatory conditions that may lead to transient or permanent sterility, protection of this organ from pathogens is an essential aspect of reproductive physiology. The families of antimicrobial peptides β-defensins and the pattern-recognition receptors Toll-like (TLR) mediate innate immunity in various vertebrates including avian species. As rooster infertility is a major concern in the poultry industry, the objectives of this study were to determine the expression profile of the entire family of the avian β-defensins (AvBD) and TLR genes in the rooster epididymis, to investigate whether sexual maturation affects their epididymidal mRNA abundance and to determine the changes in their expression levels in response to Salmonella enteritidis (SE) infection in the epididymis of sexually mature roosters. RNA was extracted from the epididymis of healthy pubertal, sexually mature and aged birds, and from sexually mature SE infected birds. RT-PCR analysis revealed that 10 members of the AvBD and nine members of the TLR gene families were expressed in the epididymis. Quantitative real-time PCR analysis revealed that the epididymidal mRNA abundance of certain AvBD and TLR genes was developmentally regulated with respect to sexual maturation. SE infection resulted in a significant induction of AvBD 1, 9, 10, 12 and 14, as well as TLR 1-2, 2-1, 2-2, 4, 5 and 7 genes, in the epididymis of sexually mature roosters, compared to healthy birds of the same age. These findings provide strong evidence to suggest that the rooster epididymis is capable of initiating an inflammatory response to Salmonella, through activation of certain members of the AvBD and TLR gene families. PMID:23830764

  13. Genetic variations in toll-like receptor 4 in Mexican-Mestizo patients with intra-abdominal infection and/or pneumonia.

    PubMed

    Rodriguez-Osorio, Carlos A; Lima, Guadalupe; Herrera-Caceres, Jaime O; Villegas-Torres, Beatriz E; Zuñiga, Joaquin; Ponce-de-Leon, Sergio; Llorente, Luis; Sifuentes-Osornio, Jose

    2013-06-01

    Sepsis is a leading cause of death around the world, and 73-83% of all sepsis cases requiring attention in intensive care units are linked to intra-abdominal infection (IAI) or pneumonia. The activation of innate immunity is central to the manifestation of sepsis, and toll-like receptor (TLR) 4 plays an important role in this activation process. The 299G and 399I alleles of TLR4 have been linked with an increased risk of Gram-negative bacteria (GNB) infections and septic shock in some populations. This case-control study evaluated the prevalence of D299G/T399I polymorphisms in Mexican patients with IAI and/or pneumonia and in healthy controls. Genotyping revealed that 1 in 44 patients (2.3%; CI 95%: 0.05-12.0%) and 4 in 126 controls (3.2%; CI 95%: 0.9-7.9%) were heterozygous for both the D299G and T399l polymorphisms (OR: 0.71, CI 95%: 0.01-7.44, p = NS), confirming the co-segregation of these alleles in this population. Furthermore, the patients with a GNB infection and severe sepsis were not carriers of the risk alleles. In summary, this report shows that the frequency of the D299G and T399I polymorphisms in Mexican-Mestizos is lower than anticipated in comparison with other ethnic groups, emphasizing the variable distribution of TLR4 polymorphisms among different populations. Consequently, this study was not able to detect associations between TLR4 polymorphisms and sepsis in this population.

  14. GS-9620, an Oral Agonist of Toll-Like Receptor-7, Induces Prolonged Suppression of Hepatitis B Virus in Chronically Infected Chimpanzees

    PubMed Central

    Lanford, Robert E.; Guerra, Bernadette; Chavez, Deborah; Giavedoni, Luis; Hodara, Vida L.; Brasky, Kathleen M.; Fosdick, Abigail; Frey, Christian R.; Zheng, Jim; Wolfgang, Grushenka; Halcomb, Randall L.; Tumas, Daniel B.

    2013-01-01

    Background & Aims Direct-acting anti-viral agents suppress hepatitis B virus (HBV) load but must be given lifelong. Stimulation of the innate immune system could increase its ability to control the virus and have long lasting effects, after a finite regimen. We investigated the effects of immune activation with GS-9620—a potent and selective orally active small molecule agonist of Toll-Like Receptor (TLR)7—in chimpanzees with chronic HBV infection. Methods GS-9620 was administered to chimpanzees every other day (3 times each week) for 4 weeks at 1 mg/kg and, after a 1 week rest, for 4 weeks at 2 mg/kg. We measured viral load in plasma and liver samples, the pharmacokinetics of GS-9620, and the following pharmacodynamics parameters: interferon (IFN)-stimulated gene expression, cytokine and chemokine levels, lymphocyte and natural killer cell activation, and viral antigen expression. Clinical pathology parameters were monitored to determine the safety and tolerability of GS-9620. Results Short-term oral administration of GS-9620 provided long-term suppression of serum and liver HBV DNA. The mean maximum reduction of viral DNA was 2.2 logs, which occurred within 1 week of the end of GS-9620 administration; reductions of greater than 1 log persisted for months. Serum levels of HB surface antigen and HB e antigen, and numbers of HBV antigen-positive hepatocytes, were reduced as hepatocyte apoptosis increased. GS-9620 administration induced production of IFN-α and other cytokines and chemokines, and activated ISGs, natural killer cells, and lymphocyte subsets. Conclusions The small molecule GS-9620 activates TLR-7 signaling in immune cells of chimpanzees to induce clearance of HBV-infected cells. This reagent might be developed for treatment of patients with chronic HBV infection. PMID:23415804

  15. Intrahepatic Toll-Like Receptor 3 in Chronic HBV Infection Subjects: Asymptomatic Carriers, Active Chronic Hepatitis, Cirrhosis, and Hepatocellular Carcinoma

    PubMed Central

    Yin, Jia Wen; Ping Huang, Mao; Zhong, Bei

    2016-01-01

    Background The entire disease spectrum of chronic HBV infection (CHB) includes asymptomatic carriers (AC), active chronic hepatitis (ACH), cirrhosis (Cir), and hepatocellular carcinoma (HCC). Previous study have demonstrated that the costimulation profiles from the livers of patients influenced immune responses and played various immunological roles in AC, ACH, Cir, and HCC. In addition, activation of TLR3 signaling in the liver may contribute to HBV clearance, although some HBV components are able to block TLR3 signaling and counteract HBV clearance through positive or negative feedback loops. Previous clinical studies have demonstrated that different TLR3 expressions are present in ACH patients, but no studies investigated the expression of TLR3 proteins in the livers of patients with AC, Cir, or HCC. Objectives This study investigated intrahepatic TLR3 expression throughout the entire disease spectrum of CHB patients and assessed the interrelations between TLR3 and costimulation proteins. Patients and Methods Patients with ACH, Cir, HCC, and AC and healthy donors (HD) were recruited. TLR3 expression in the livers of patients were investigated using western blot analysis and immunohistochemistry. Correlations between TLR3 and costimulation proteins, including CD80, CD86, CD83, CD28, CTLA-4, CD40, and ICAM-1, were assessed. Results The TLR3 protein in the ACH group tended toward reduction although the P Value of the comparison between the ACH group and HD group was not statistically significant. The TLR3 levels in the HCC, AC, and Cir groups were higher than those in the HD and ACH groups. TLR3 was not interrelated with all costimulation proteins in the DCs and T cells in all five groups. No group presented any interrelation between TLR3 and CD40, except the AC group. Conclusions The AC, HCC, and Cir patients displayed increased levels of the intrahepatic TLR3 protein compared to the HD and AC patients. Both activation of TLR3/INF-β signaling and inhibition of

  16. A species-specific activation of Toll-like receptor signaling in bovine and sheep bronchial epithelial cells triggered by Mycobacterial infections.

    PubMed

    Ma, Yan; Han, Fei; Liang, Jinping; Yang, Jiali; Shi, Juan; Xue, Jing; Yang, Li; Li, Yong; Luo, Meihui; Wang, Yujiong; Wei, Jun; Liu, Xiaoming

    2016-03-01

    Pulmonary tuberculosis caused by a Mycobacterium infection remains a major public health problem in most part of the world, in part owing to the transmission of its pathogens between hosts including human, domestic and wild animals. To date, molecular mechanisms of the pathogenesis of TB are still incompletely understood. In addition to alveolar macrophages, airway epithelial cells have also been recently recognized as main targets for Mycobacteria infections. In an effort to understand the pathogen-host interaction between Mycobacteria and airway epithelial cells in domestic animals, in present study, we investigated the Toll-like receptor (TLR) signaling in bovine and sheep airway epithelial cells in response to an infection of Mycobacterium tuberculosis avirulent H37Ra stain or Mycobacterium bovis BCG vaccine strain, using primary air-liquid interface (ALI) bronchial epithelial culture models. Our results revealed a host and pathogen species-specific TLR-mediated recognition of pathogen-associated molecular patterns (PAMPs), induction and activation of TLR signaling pathways, and substantial induction of inflammatory response in bronchial epithelial cells in response to Mycobacteria infections between these two species. Interestingly, the activation TLR signaling in bovine bronchial epithelial cells induced by Mycobacteria infection was mainly through a myeloid differentiation factor 88 (MyD88)-independent TLR signaling pathway, while both MyD88-dependent and independent TLR signaling cascades could be induced in sheep epithelial cells. Equally noteworthy, a BCG infection was able to induce both MyD88-dependent and independent signaling in sheep and bovine airway epithelial cells, but more robust inflammatory responses were induced in sheep epithelial cells relative to the bovines; whereas an H37Ra infection displayed an ability to mainly trigger a MyD88-independent TLR signaling cascade in these two host species, and induce a more extent expression of

  17. A novel mouse model of Campylobacter jejuni gastroenteritis reveals key pro-inflammatory and tissue protective roles for Toll-like receptor signaling during infection.

    PubMed

    Stahl, Martin; Ries, Jenna; Vermeulen, Jenny; Yang, Hong; Sham, Ho Pan; Crowley, Shauna M; Badayeva, Yuliya; Turvey, Stuart E; Gaynor, Erin C; Li, Xiaoxia; Vallance, Bruce A

    2014-07-01

    Campylobacter jejuni is a major source of foodborne illness in the developed world, and a common cause of clinical gastroenteritis. Exactly how C. jejuni colonizes its host's intestines and causes disease is poorly understood. Although it causes severe diarrhea and gastroenteritis in humans, C. jejuni typically dwells as a commensal microbe within the intestines of most animals, including birds, where its colonization is asymptomatic. Pretreatment of C57BL/6 mice with the antibiotic vancomycin facilitated intestinal C. jejuni colonization, albeit with minimal pathology. In contrast, vancomycin pretreatment of mice deficient in SIGIRR (Sigirr(-/-)), a negative regulator of MyD88-dependent signaling led to heavy and widespread C. jejuni colonization, accompanied by severe gastroenteritis involving strongly elevated transcription of Th1/Th17 cytokines. C. jejuni heavily colonized the cecal and colonic crypts of Sigirr(-/-) mice, adhering to, as well as invading intestinal epithelial cells. This infectivity was dependent on established C. jejuni pathogenicity factors, capsular polysaccharides (kpsM) and motility/flagella (flaA). We also explored the basis for the inflammatory response elicited by C. jejuni in Sigirr(-/-) mice, focusing on the roles played by Toll-like receptors (TLR) 2 and 4, as these innate receptors were strongly stimulated by C. jejuni. Despite heavy colonization, Tlr4(-/-)/Sigirr(-/-) mice were largely unresponsive to infection by C. jejuni, whereas Tlr2(-/-)/Sigirr(-/-) mice developed exaggerated inflammation and pathology. This indicates that TLR4 signaling underlies the majority of the enteritis seen in this model, whereas TLR2 signaling had a protective role, acting to promote mucosal integrity. Furthermore, we found that loss of the C. jejuni capsule led to increased TLR4 activation and exaggerated inflammation and gastroenteritis. Together, these results validate the use of Sigirr(-/-) mice as an exciting and relevant animal model for

  18. Susceptibility to paratuberculosis infection in cattle is associated with single nucleotide polymorphisms in Toll-like receptor 2 which modulate immune responses against Mycobacterium avium subspecies paratuberculosis.

    PubMed

    Koets, A; Santema, W; Mertens, H; Oostenrijk, D; Keestra, M; Overdijk, M; Labouriau, R; Franken, P; Frijters, A; Nielen, M; Rutten, V

    2010-03-01

    Paratuberculosis is a chronic intestinal infection in ruminants, caused by Mycobacterium avium subspecies paratuberculosis (Map). To study the role of host genetics in disease susceptibility, the Toll-like receptor 2 (TLR2) gene, selected based on its potential role in immunity to mycobacterial infections, was analyzed for single nucleotide polymorphisms (SNP) and their potential association with disease. For SNP discovery and to study SNP association with disease, a case-control study including 24 cows from farms with paratuberculosis was conducted. Sequence analysis of the TLR2 genes from 12 paratuberculosis-infected animals and 12 age-matched healthy herd mates revealed 21 different SNP. The TLR2-1903 T/C SNP was significantly associated with resistance to Map. This and four additional TLR2 SNP were studied in a subsequent observational field study with 553 cows from farms with paratuberculosis. The allelic distribution of the TLR2-1903 T/C SNP was confirmed to be significantly different between the infected and non-infected animals. For the TLR2-1903 T/C SNP the odds ratio was calculated, and similar to the dominance model in the association study, the CT and CC genotypes were compared to the TT genotype. Cows with the TLR2-1903 T/C mutation (i.e., the CT and CC genotypes) were at 1.7 (95% CI: 1.2, 2.8) times the odds of being Map-infected compared to cows with the TT genotype. In in vitro functional assays, monocyte-derived macrophages from animals with a TLR2-1903 TT genotype produced more IL12p40 and IL1beta when stimulated with Map compared to cells derived from TLR2-1903 CT and CC genotypes. Also, T cell proliferative responses to mycobacterial antigens were higher in animals with a TLR2-1903 TT genotype. In conclusion, we have found a significant association between SNP TLR2-1903 T/C in the bovine TLR2 gene and bovine paratuberculosis infection. This SNP and other genetic markers could be useful in marker-assisted breeding strategies as an additional tool

  19. Hepatic and Renal Cytochrome P450 Gene Regulation During Citrobacter rodentium Infection in Wildtype and Toll-like Receptor 4 Mutant Mice

    PubMed Central

    Richardson, Terrilyn A.; Sherman, Melanie; Antonovic, Leposava; Kardar, Sean S.; Strobel, Henry W.; Kalman, Daniel; Morgan, Edward T.

    2005-01-01

    C. rodentium is the rodent equivalent of human enteropathogenic E. coli infection. This study investigated regulation of hepatic and renal cytochrome P450 (P450) mRNAs, hepatic P450 proteins, cytokines and acute phase proteins during C. rodentium infection. Female C3H/HeOuJ (HeOu) and C3H/HeJ (HeJ) mice (which lack functional toll-like receptor 4 [TLR4]) were infected with C. rodentium by oral gavage, and sacrificed 6 days later. Hepatic CYP4A10 and 4A14 mRNAs were decreased in HeOu mice (<4% of control). CYP3A11, 2C29, 4F14, and 4F15 mRNAs were reduced to 16–55% of control levels, whereas CYP2A5, 4F16, and 4F18 mRNAs were induced (180, 190, and 600% of control, respectively). The pattern of P450 regulation in HeJ mice was similar to that in HeOu mice for most P450s, with the exception of the TLR4-dependence of CYP4F15. Hepatic CYP2C, 3A, and 4A proteins in both groups were decreased, whereas CYP2E protein was not. Renal CYP4A10 and 4A14 mRNAs were significantly down-regulated in HeOu mice, whereas other P450s were unaffected. Most renal P450 mRNAs in infected HeJ mice were increased, notably CYP4A10, 4A14, 4F18, 2A5 and 3A13. Hepatic levels of IL-1β, IL-6, and TNFα mRNAs were significantly increased in infected HeOu mice, whereas only TNFα mRNA was significantly increased in HeJ mice. Hepatic α1-acid glycoprotein was induced in both groups, whereas α-fibrinogen and angiotensinogen were unchanged. These data indicate that hepatic inflammation induced by C. rodentium infection is mainly TLR4-independent, and suggest that hepatic P450 down-regulation in this model may be cytokine-mediated. PMID:16339354

  20. Milk Matters: Soluble Toll-Like Receptor 2 (sTLR2) in Breast Milk Significantly Inhibits HIV-1 Infection and Inflammation

    PubMed Central

    Henrick, Bethany M.; Nag, Kakon; Yao, Xiao-Dan; Drannik, Anna G.; Aldrovandi, Grace M.; Rosenthal, Kenneth L.

    2012-01-01

    The majority of infants who breastfeed from their HIV-positive mothers remain uninfected despite constant and repeated exposure to virus over weeks to years. This phenomenon is not fully understood but has been closely linked to innate factors in breast milk (BM). Most recently we have focused on one such innate factor, soluble Toll-like receptor 2 (sTLR2) for its significant contribution as an inhibitor of inflammation triggered by bacterial and viral antigens. We hypothesized that sTLR2 in BM inhibits immune activation/inflammation and HIV-1 infection. sTLR2 protein profiles were analyzed in HIV-uninfected BM and showed dramatic variability in expression concentration and predominant sTLR2 forms between women. sTLR2 immunodepleted BM, versus mock-depleted BM, incubated with Pam3CSK4 lead to significant increases in IL-8 production in a TLR2-dependant fashion in U937, HEK293-TLR2, and Caco-2. Importantly, TLR2-specific polyclonal and monoclonal antibody addition to BM prior to cell-free R5 HIV-1 addition led to significantly (P<0.01, P<0.001, respectively) increased HIV-1 infection in TZM-bl reporter cells. To confirm these findings, sTLR2-depletion in BM led to significantly (P<0.001) increased HIV-1 infection in TZM-bl cells. Notably, immunodepletion does not allow for the complete removal of sTLR2 from BM, thus functional testing shown here may underestimate the total effect elicited by sTLR2 against HIV-1 and synthetic bacterial ligand. This study provides evidence for the first time that sTLR2 in BM may provide a dual protective role for infants breastfeeding from their HIV-infected mothers by; (1) immunomodulating pro-inflammatory responses to bacterial ligands, and (2) directly inhibiting cell-free HIV-1 infection. Thus, sTLR2 in BM may be critical to infant health and prove beneficial in decreasing vertical HIV-1 transmission to infants. PMID:22792230

  1. Increased expression of Toll-like receptors 7 and 9 in myasthenia gravis thymus characterized by active Epstein-Barr virus infection.

    PubMed

    Cavalcante, Paola; Galbardi, Barbara; Franzi, Sara; Marcuzzo, Stefania; Barzago, Claudia; Bonanno, Silvia; Camera, Giorgia; Maggi, Lorenzo; Kapetis, Dimos; Andreetta, Francesca; Biasiucci, Amelia; Motta, Teresio; Giardina, Carmelo; Antozzi, Carlo; Baggi, Fulvio; Mantegazza, Renato; Bernasconi, Pia

    2016-04-01

    Considerable data implicate the thymus as the main site of autosensitization to the acetylcholine receptor in myasthenia gravis (MG), a B-cell-mediated autoimmune disease affecting the neuromuscular junction. We recently demonstrated an active Epstein-Barr virus (EBV) infection in the thymus of MG patients, suggesting that EBV might contribute to the onset or maintenance of the autoimmune response within MG thymus, because of its ability to activate and immortalize autoreactive B cells. EBV has been reported to elicit and modulate Toll-like receptor (TLR) 7- and TLR9-mediated innate immune responses, which are known to favor B-cell dysfunction and autoimmunity. Aim of this study was to investigate whether EBV infection is associated with altered expression of TLR7 and TLR9 in MG thymus. By real-time PCR, we found that TLR7 and TLR9 mRNA levels were significantly higher in EBV-positive MG compared to EBV-negative normal thymuses. By confocal microscopy, high expression levels of TLR7 and TLR9 proteins were observed in B cells and plasma cells of MG thymic germinal centers (GCs) and lymphoid infiltrates, where the two receptors co-localized with EBV antigens. An increased frequency of Ki67-positive proliferating B cells was found in MG thymuses, where we also detected proliferating cells expressing TLR7, TLR9 and EBV antigens, thus supporting the idea that EBV-associated TLR7/9 signaling may promote abnormal B-cell activation and proliferation. Along with B cells and plasma cells, thymic epithelium, plasmacytoid dendritic cells and macrophages exhibited enhanced TLR7 and TLR9 expression in MG thymus; TLR7 was also increased in thymic myeloid dendritic cells and its transcriptional levels positively correlated with those of interferon (IFN)-β. We suggested that TLR7/9 signaling may be involved in antiviral type I IFN production and long-term inflammation in EBV-infected MG thymuses. Our overall findings indicate that EBV-driven TLR7- and TLR9-mediated innate immune

  2. Toll-like Receptor function of murine macrophages, probed by cytokine induction, is biphasic and is not impaired globally with age.

    PubMed

    Pattabiraman, Goutham; Palasiewicz, Karol; Ucker, David S

    2016-07-01

    Aging is associated with a waning of normal immune function. This "immunosenescence" is characterized by a diverse repertoire of seemingly discreet and unbalanced immune alterations. A number of studies have suggested that aging-associated alterations in innate immune responsiveness, especially responsiveness dependent on Toll-like Receptor (TLR) engagement, are causally involved. We find, however, that the magnitude and dose-dependency of responsiveness to TLR engagement (assessed with respect to cytokine production) in distinct populations of murine macrophages are not altered generally with animal age or as a consequence of immunosenescence. Responses elicited with a wide array of TLR agonists were examined by extensive functional analyses, principally on the level of the individual cell. These studies reveal an intriguing "all-or-nothing" response behavior of macrophages, independent of animal age. Although reports to the contrary have been cited widely, aging-associated immune decline cannot be attributed to widespread alterations in the extents of TLR-dependent innate immune macrophage responses. PMID:27453067

  3. [Influence of Opiate Abuse on Expression of Toll-like Receptor 9 in Peripheral Blood Mononuclear Cells of HIV-1-Infected Individuals].

    PubMed

    Pan, Peijiang; Wei, Fumei; Jiang, Junjun; Liang, Bingyu; Huang, Jiegang; Liao, Yanyan; Su, Jinming; Li, Yu; Yang, Xiaoyi; Chen, Hui; Ye, Li; Liang, Hao

    2015-03-01

    The aim of this study was to investigate the influence of opiate abuse on the expression of Toll-like receptor 9 (TLR9) in the peripheral blood mononuclear cells (PBMCs) of HIV-1-infected patients and to elucidate possible mechanisms involved in the enhancement of HIV-1 replication by opiate abuse. A total of 200 participants were enrolled in the study by random selection from methadone treatment centers and voluntary HIV counseling and testing centers in the cities of Nanning, Liuzhou, and Qinzhou. These participants included 50 HIV-positive opiate abusers (Opiates HIV(+) group), 50 HIV-negative opiate abusers (Opiates HIV(-) group), 50 HIV-positive subjects who were not opiate abusers (Non-opiates HIV (+) group), and 50 HIV-negative subjects who were not opiate abusers (Control group). PBMCs were isolated from the peripheral blood samples from the subjects and the expression levels of TLR9 mRNA and protein were determined by q-PCR and western blot respectively. There was no significant difference among the four groups in age, gender, nationality, domicile, marital status, educational background or duration of drug abuse (P > 0.05). The median viral loads of the Opiates HIV(+) were significantly higher than those of the Non-Opiates HIV(+) groups (4.450 x 10(3) and 3.977 x 10(3) copies/mL respectively, P < 0.05). The relative expression levels of TLR9 mRNA in the Opiates HIV(+), Non-Opiates HIV(+), Opiates HIV(-) and Control groups were (2.13 +/- 1.59) x 10(-3), (3.66 +/- 2.22) x 10(-3), (1.96 +/- 1.42) x 10(-3) and (7.66 +/- 4.87) x 10(-3), respectively. The expression of TLR9 mRNA was significantly lower in both HIV-1-infected and -uninfected groups of opiate abusers compared with groups of non-abusers (P < 0.05). There was no significant difference in TLR9 mRNA expression levels between the Opiates HIV(+) group and the Opiates HIV(-) group (P > 0.05). However, in the non-opiate groups, the expression levels of TLR9 mRNA in the HIV(+) group were significantly

  4. CD14 Mediates Toll-like Receptor 4 (TLR4) Endocytosis and Spleen Tyrosine Kinase (Syk) and Interferon Regulatory Transcription Factor 3 (IRF3) Activation in Epithelial Cells and Impairs Neutrophil Infiltration and Pseudomonas aeruginosa Killing in Vivo*

    PubMed Central

    Roy, Sanhita; Karmakar, Mausita; Pearlman, Eric

    2014-01-01

    In the current study, we examined the role of CD14 in regulating LPS activation of corneal epithelial cells and Pseudomonas aeruginosa corneal infection. Our findings demonstrate that LPS induces Toll-like receptor 4 (TLR4) internalization in corneal epithelial cells and that blocking with anti-CD14 selectively inhibits TLR4 endocytosis, spleen tyrosine kinase (Syk) and IRF3 phosphorylation, and production of CCL5/RANTES and IFN-β, but not IL-8. Using a murine model of P. aeruginosa corneal infection, we show that although infected CD14−/− corneas produce less CCL5, they exhibit significantly increased CXC chemokine production, neutrophil recruitment to the corneal stroma, and bacterial clearance than C57BL/6 mice. We conclude that CD14 has a critical role in mediating TLR4 signaling through IRF3 in resident corneal epithelial cells and macrophages and thereby modulates TLR4 cell surface activation of the MyD88/NF-κB/AP-1 pathway and production of CXC chemokines and neutrophil infiltration to infected tissues. PMID:24275652

  5. A role for Toll-like receptor 4 in the host response to the lung infection of Yersinia pseudotuberculosis in mice.

    PubMed

    Choi, Jin-A; Jeong, Yu-Jin; Kim, Jae-Eun; Kang, Min-Jung; Kim, Jee-Cheon; Oh, Sang-Muk; Lee, Kyung-Bok; Kim, Dong-Hyun; Kim, Dong-Jae; Park, Jong-Hwan

    2016-02-01

    Although a Yersinia pseudotuberculosis (Yptb) lung infection model has been developed to study Y. pestis pathogenesis, it is still necessary to establish a new animal model to mimic the pathophysiological features induced by Y. pestis infection. Here, we provide a new lung infection model using the Yptb strain, IP2777, which displayed rapid spread of bacteria to the liver, spleen, and blood. In addition, we examined whether TLR4 is involved in Yptb-induced pathogenesis in the lung infection model of mice we generated. Following lung infection of WT and TLR4-deficient mice with the Yptb strain IP2777, the survival rate, bacterial colonization, histopathology, and level of cytokines and chemokines in the lung, spleen, liver, and blood were analyzed. TLR4-deficient mice had a lower survival rate than WT mice in response to Yptb lung infection. Although the bacterial colonization and pathology of the lung were comparable between WT and TLR4-deficient mice, those of the spleen and liver were more severe in TLR4-deficient mice. In addition, the levels of TNF-α and CXCL2 in the liver and IL-6 and CXCL2 in the blood were higher in TLR4-deficient mice than in WT mice. Our results demonstrate that TLR4 is necessary for optimal host protection against Yptb lung infection and TLR4-deficient mice may serve as a better genetic model of Yptb infection for mimicking Y. pestis infection. PMID:26851596

  6. Bovine colostrum enhances natural killer cell activity and immune response in a mouse model of influenza infection and mediates intestinal immunity through toll-like receptors 2 and 4.

    PubMed

    Wong, Eric B; Mallet, Jean-François; Duarte, Jairo; Matar, Chantal; Ritz, Barry W

    2014-04-01

    Oral administration of bovine colostrum affects intestinal immunity, including an increased percentage of natural killer (NK) cells. However, effects on NK cell cytotoxic activity and resistance to infection as well as a potential mechanism remain unclear. Therefore, we investigated the effects of bovine colostrum (La Belle, Inc, Bellingham, WA) on the NK cytotoxic response to influenza infection and on toll-like receptor (TLR) activity in a primary intestinal epithelial cell culture. We hypothesized that colostrum would increase NK cell activity and that TLR-2 and TLR-4 blocking would reduce interleukin 6 production by epithelial cells in response to contact stimulation with colostrum. Four-month-old female C57BL/6 mice were supplemented with 1 g of colostrum per kilogram of body weight before and after infection with influenza A virus (H1N1). Animals were assessed for weight loss, splenic NK cell activity, and lung virus titers. Colostrum-supplemented mice demonstrated less reduction in body weight after influenza infection, indicating a less severe infection, increased NK cell cytotoxicity, and less virus burden in the lungs compared with controls. Colostrum supplementation enhanced NK cell cytotoxicity and improved the immune response to primary influenza virus infection in mice. To investigate a potential mechanism, a primary culture of small intestine epithelial cells was then stimulated with colostrum. Direct activation of epithelial cells resulted in increased interleukin 6 production, which was inhibited with TLR-2 and TLR-4 blocking antibodies. The interaction between colostrum and immunity may be dependent, in part, on the interaction of colostrum components with innate receptors at the intestinal epithelium, including TLR-2 and TLR-4. PMID:24774068

  7. Bovine colostrum enhances natural killer cell activity and immune response in a mouse model of influenza infection and mediates intestinal immunity through toll-like receptors 2 and 4.

    PubMed

    Wong, Eric B; Mallet, Jean-François; Duarte, Jairo; Matar, Chantal; Ritz, Barry W

    2014-04-01

    Oral administration of bovine colostrum affects intestinal immunity, including an increased percentage of natural killer (NK) cells. However, effects on NK cell cytotoxic activity and resistance to infection as well as a potential mechanism remain unclear. Therefore, we investigated the effects of bovine colostrum (La Belle, Inc, Bellingham, WA) on the NK cytotoxic response to influenza infection and on toll-like receptor (TLR) activity in a primary intestinal epithelial cell culture. We hypothesized that colostrum would increase NK cell activity and that TLR-2 and TLR-4 blocking would reduce interleukin 6 production by epithelial cells in response to contact stimulation with colostrum. Four-month-old female C57BL/6 mice were supplemented with 1 g of colostrum per kilogram of body weight before and after infection with influenza A virus (H1N1). Animals were assessed for weight loss, splenic NK cell activity, and lung virus titers. Colostrum-supplemented mice demonstrated less reduction in body weight after influenza infection, indicating a less severe infection, increased NK cell cytotoxicity, and less virus burden in the lungs compared with controls. Colostrum supplementation enhanced NK cell cytotoxicity and improved the immune response to primary influenza virus infection in mice. To investigate a potential mechanism, a primary culture of small intestine epithelial cells was then stimulated with colostrum. Direct activation of epithelial cells resulted in increased interleukin 6 production, which was inhibited with TLR-2 and TLR-4 blocking antibodies. The interaction between colostrum and immunity may be dependent, in part, on the interaction of colostrum components with innate receptors at the intestinal epithelium, including TLR-2 and TLR-4.

  8. Key Role of Toll-Like Receptor 2 in the Inflammatory Response and Major Histocompatibility Complex Class II Downregulation in Brucella abortus-Infected Alveolar Macrophages

    PubMed Central

    Ferrero, Mariana C.; Hielpos, M. Soledad; Carvalho, Natalia B.; Barrionuevo, Paula; Corsetti, Patricia P.; Giambartolomei, Guillermo H.; Oliveira, Sergio C.

    2014-01-01

    Alveolar macrophages (AM) seem to constitute the main cellular target of inhaled brucellae. Here, we show that Brucella abortus invades and replicates in murine AM without inducing cytotoxicity. B. abortus infection induced a statistically significant increase of tumor necrosis factor alpha (TNF-α), CXCL1 or keratinocyte chemoattractant (KC), interleukin-1β (IL-1β), IL-6, and IL-12 in AM from C57BL/6 mice and BALB/c mice, but these responses were generally weaker and/or delayed compared to those elicited in peritoneal macrophages. Studies using knockout mice for TLR2, TLR4, and TLR9 revealed that TNF-α and KC responses were mediated by TLR2 recognition. Brucella infection reduced in a multiplicity of infection-dependent manner the expression of major histocompatibility complex class II (MHC-II) molecules induced by gamma interferon (IFN-γ) in AM. The same phenomenon was induced by incubation with heat-killed B. abortus (HKBA) or the lipidated form of the 19-kDa outer membrane protein of Brucella (L-Omp19), and it was shown to be mediated by TLR2 recognition. In contrast, no significant downregulation of MHC-II was induced by either unlipidated Omp19 or Brucella LPS. In a functional assay, treatment of AM with either L-Omp19 or HKBA reduced the MHC-II-restricted presentation of OVA peptides to specific T cells. One week after intratracheal infection, viable B. abortus was detected in AM from both wild-type and TLR2 KO mice, but CFU counts were higher in the latter. These results suggest that B. abortus survives in AM after inhalatory infection in spite of a certain degree of immune control exerted by the TLR2-mediated inflammatory response. Both the modest nature of the latter and the modulation of MHC-II expression by the bacterium may contribute to such survival. PMID:24478078

  9. Key role of Toll-like receptor 2 in the inflammatory response and major histocompatibility complex class ii downregulation in Brucella abortus-infected alveolar macrophages.

    PubMed

    Ferrero, Mariana C; Hielpos, M Soledad; Carvalho, Natalia B; Barrionuevo, Paula; Corsetti, Patricia P; Giambartolomei, Guillermo H; Oliveira, Sergio C; Baldi, Pablo C

    2014-02-01

    Alveolar macrophages (AM) seem to constitute the main cellular target of inhaled brucellae. Here, we show that Brucella abortus invades and replicates in murine AM without inducing cytotoxicity. B. abortus infection induced a statistically significant increase of tumor necrosis factor alpha (TNF-α), CXCL1 or keratinocyte chemoattractant (KC), interleukin-1β (IL-1β), IL-6, and IL-12 in AM from C57BL/6 mice and BALB/c mice, but these responses were generally weaker and/or delayed compared to those elicited in peritoneal macrophages. Studies using knockout mice for TLR2, TLR4, and TLR9 revealed that TNF-α and KC responses were mediated by TLR2 recognition. Brucella infection reduced in a multiplicity of infection-dependent manner the expression of major histocompatibility complex class II (MHC-II) molecules induced by gamma interferon (IFN-γ) in AM. The same phenomenon was induced by incubation with heat-killed B. abortus (HKBA) or the lipidated form of the 19-kDa outer membrane protein of Brucella (L-Omp19), and it was shown to be mediated by TLR2 recognition. In contrast, no significant downregulation of MHC-II was induced by either unlipidated Omp19 or Brucella LPS. In a functional assay, treatment of AM with either L-Omp19 or HKBA reduced the MHC-II-restricted presentation of OVA peptides to specific T cells. One week after intratracheal infection, viable B. abortus was detected in AM from both wild-type and TLR2 KO mice, but CFU counts were higher in the latter. These results suggest that B. abortus survives in AM after inhalatory infection in spite of a certain degree of immune control exerted by the TLR2-mediated inflammatory response. Both the modest nature of the latter and the modulation of MHC-II expression by the bacterium may contribute to such survival. PMID:24478078

  10. 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

    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

  11. 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

  12. Molecular cloning and comparative responses of Toll-like receptor 22 following ligands stimulation and parasitic infection in yellowtail (Seriola lalandi).

    PubMed

    Reyes-Becerril, Martha; Ascencio-Valle, Felipe; Alamillo, Erika; Hirono, Ikuo; Kondo, Hidehiro; Jirapongpairoj, Walissara; Angulo, Carlos

    2015-10-01

    TLR22 is exclusively present in teleosts and amphibians and is expected to play the distinctive role in innate immunity. In this study, we cloned the full-length cDNA sequence of yellowtail (Seriola lalandi) TLR22 (SlTLR22). The complete cDNA sequence of SlTLR22 was 4208 bp and encodes a polypeptide of 961 amino acids. Analysis of the deduced amino acid sequence indicated that SlTLR22 has typical structural features of proteins belonging to the TLR family. These included 17 LRR domains (residues 91-633) and one C-terminal LRR domain (LRR-CT, residues 693-744) in the extracellular region, and a TIR domain (residues 800-943) in the cytoplasmic region. Comparison with homologous proteins showed that the deduced SlTLR22 has the highest sequence identity to turbot TLR22 (76%). Quantitative real-time PCR (qPCR) analysis demonstrated the constitutive expression of SlTLR22 mRNA in all examined tissues with higher levels in the head kidney, intestine, skin and spleen. Further, SlTLR22 expression was significantly up-regulated following TLR ligands injection with lipopolysaccharide (LPS), CpG ODN2006 and polyinosinic: polycytidylic acid (poly I:C) in spleen and liver. Amyloodinium ocellatum infection also induced a high expression of SlTLR22 in spleen, intestine, muscle, skin and gill, with maximum increases ranging from 1000 to 100 fold upon different ligands and organs. Finally, histological examination in gill tissue confirmed infection by the parasite and histopathological lesion was observed also in spleen and skin. These findings suggest a possible role of SlTLR22 in the immune responses to the infections of a broad range of pathogens that include DNA and RNA viruses and parasites. PMID:26102460

  13. Transcription of Toll-Like Receptors 2, 3, 4 and 9, FoxP3 and Th17 Cytokines in a Susceptible Experimental Model of Canine Leishmania infantum Infection

    PubMed Central

    Hosein, Shazia; Rodríguez-Cortés, Alhelí; Blake, Damer P.; Allenspach, Karin; Alberola, Jordi; Solano-Gallego, Laia

    2015-01-01

    Canine leishmaniosis (CanL) due to Leishmania infantum is a chronic zoonotic systemic disease resulting from complex interactions between protozoa and the canine immune system. Toll-like receptors (TLRs) are essential components of the innate immune system and facilitate the early detection of many infections. However, the role of TLRs in CanL remains unknown and information describing TLR transcription during infection is extremely scarce. The aim of this research project was to investigate the impact of L. infantum infection on canine TLR transcription using a susceptible model. The objectives of this study were to evaluate transcription of TLRs 2, 3, 4 and 9 by means of quantitative reverse transcription polymerase chain reaction (qRT-PCR) in skin, spleen, lymph node and liver in the presence or absence of experimental L. infantum infection in Beagle dogs. These findings were compared with clinical and serological data, parasite densities in infected tissues and transcription of IL-17, IL-22 and FoxP3 in different tissues in non-infected dogs (n = 10), and at six months (n = 24) and 15 months (n = 7) post infection. Results revealed significant down regulation of transcription with disease progression in lymph node samples for TLR3, TLR4, TLR9, IL-17, IL-22 and FoxP3. In spleen samples, significant down regulation of transcription was seen in TLR4 and IL-22 when both infected groups were compared with controls. In liver samples, down regulation of transcription was evident with disease progression for IL-22. In the skin, upregulation was seen only for TLR9 and FoxP3 in the early stages of infection. Subtle changes or down regulation in TLR transcription, Th17 cytokines and FoxP3 are indicative of the silent establishment of infection that Leishmania is renowned for. These observations provide new insights about TLR transcription, Th17 cytokines and Foxp3 in the liver, spleen, lymph node and skin in CanL and highlight possible markers of disease susceptibility in

  14. 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 Central

    Xu, Cheng; Evensen, Øystein; Mweemba, Hetron Munang’andu

    2016-01-01

    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. PMID:27110808

  15. Toll-Like Receptor 2-Mediated Innate Immune Responses against Junín Virus in Mice Lead to Antiviral Adaptive Immune Responses during Systemic Infection and Do Not Affect Viral Replication in the Brain

    PubMed Central

    Cuevas, Christian D.

    2014-01-01

    ABSTRACT Successful adaptive immunity to virus infection often depends on the initial innate response. Previously, we demonstrated that Junín virus, the etiological agent responsible for Argentine hemorrhagic fever (AHF), activates an early innate immune response via an interaction between the viral glycoprotein and Toll-like receptor 2 (TLR2). Here we show that TLR2/6 but not TLR1/2 heterodimers sense Junín virus glycoprotein and induce a cytokine response, which in turn upregulates the expression of the RNA helicases RIG-I and MDA5. NF-κB and Erk1/2 were important in the cytokine response, since both proteins were phosphorylated as a result of the interaction of virus with TLR2, and treatment with an Erk1/2-specific inhibitor blocked cytokine production. We show that the Junín virus glycoprotein activates cytokine production in a human macrophage cell line as well. Moreover, we show that TLR2-mediated immune response plays a role in viral clearance because wild-type mice cleared Candid 1 (JUNV C1), the vaccine strain of Junín virus, more rapidly than did TLR2 knockout mice. This clearance correlated with the generation of Junín virus-specific CD8+ T cells. However, infected wild-type and TLR2 knockout mice developed TLR2-independent blocking antibody responses with similar kinetics. We also show that microglia and astrocytes but not neurons are susceptible to infection with JUNV C1. Although JUNV C1 infection of the brain also triggered a TLR2-dependent cytokine response, virus levels were equivalent in wild-type and TLR2 knockout mice. IMPORTANCE Junín virus is transmitted by rodents native to Argentina and is associated with both systemic disease and, in some patients, neurological symptoms. Humans become infected when they inhale aerosolized Junín virus. AHF has a 15 to 30% mortality rate, and patients who clear the infection develop a strong antibody response to Junín virus. Here we investigated what factors determine the immune response to Jun

  16. Toll-like Receptor 4 in CNS Pathologies

    PubMed Central

    Buchanan, Madison M.; Hutchinson, Mark; Watkins, Linda R.; Yin, Hang

    2010-01-01

    The responses of the brain to infection, ischemia and trauma share remarkable similarities. These and other conditions of the CNS coordinate an innate immune response marked by activation of microglia, the macrophage-like cells of the nervous system. An important contributor to microglial activation is toll-like receptor 4 (TLR4), a pathogen-associated molecular pattern receptor known to initiate an inflammatory cascade in response to various CNS stimuli. The present review traces new efforts to characterize and control the contribution of TLR4 to inflammatory etiologies of the nervous system. PMID:20402965

  17. Toll-like receptor signaling in neonatal sepsis and inflammation: a matter of orchestration and conditioning.

    PubMed

    Glaser, Kirsten; Speer, Christian P

    2013-12-01

    Altered neonatal Toll-like receptor (TLR) function is hypothesized to contribute to the heightened susceptibility to infection and perpetuated inflammation in term and preterm neonates, clinically evident in neonatal sepsis and increased rates of inflammatory disorders. Current data indicate that basal TLR expression in term neonates equals adult expression patterns, while expression in preterm infants seems to increase, depending on gestational age. Regarding TLR signaling, some studies suggest TLR incompetence in neonates associated with impaired pro-inflammatory responses, others describe neonatal TLR function well developed and allude to its hyper-inflammation tendency. We discuss the competing positions and considerable limitations of research approaches and conclude that neonatal innate immunity is not generally less able to respond to TLR stimulation. Moreover, we describe pre-conditioning factors other than immaturity having a comparable impact. In the long term, better understanding of the complex interplay of pre- and postnatal conditions and maturation-dependent neonatal TLR function may provide new therapeutic approaches.

  18. Toll-like Receptors in Tumor Immunotherapy

    PubMed Central

    Paulos, Chrystal M.; Kaiser, Andrew; Wrzesinski, Claudia; Hinrichs, Christian S.; Cassard, Lydie; Boni, Andrea; Muranski, Pawel; Sanchez-Perez, Luis; Palmer, Douglas C.; Yu, Zhiya; Antony, Paul A.; Gattinoni, Luca; Rosenberg, Steven A.; Restifo, Nicholas P.

    2007-01-01

    Lymphodepletion with chemotherapeutic agents or total body irradiation (TBI) before adoptive transfer of tumor-specific T cells is a critical advancement in the treatment of patients with melanoma. More than 50% of patients that are refractory to other treatments experience an objective or curative response with this approach. Emerging data indicate that the key mechanisms underlying how TBI augments the functions of adoptively transferred T cells include (a) the depletion of regulatory Tcells (Treg) and myeloid-derived suppressor cells that limit the function and proliferation of adoptively transferred cells; (b) the removal of immune cells that act as “sinks” for homeostatic cytokines, whose levels increase after lymphodepletion; and (c) the activation of the innate immune system via Toll-like receptor 4 signaling, which is engaged by microbial lipopolysaccharide that translocated across the radiation-injured gut. Here, we review these mechanisms and focus on the effect of Toll-like receptor agonists in adoptive immunotherapy. We also discuss alternate regimens to chemotherapy or TBI, which might be used to safely treat patients with advanced disease and promote tumor regression. PMID:17875756

  19. Molecular characterization of toll-like receptor 2 (TLR2), analysis of its inductive expression and associated down-stream signaling molecules following ligands exposure and bacterial infection in the Indian major carp, rohu (Labeo rohita).

    PubMed

    Samanta, Mrinal; Swain, Banikalyan; Basu, Madhubanti; Panda, Padmaja; Mohapatra, Girish B; Sahoo, Bikash R; Maiti, Nikhil K

    2012-03-01

    Toll-like receptors (TLRs) are one of the key components of innate immunity. Among various TLR types, TLR2 is involved in recognizing specific microbial structures such as peptidoglycan (PGN), lipoteichoic acid (LTA), zymosan etc., and after binding them it triggers myeloid differentiation primary response gene 88 (MyD88)-dependent signaling pathway to induce various cytokines. In this report, TLR2 gene was cloned and characterized in rohu (Labeo rohita), which is highly commercially important fish species in the farming-industry of Indian subcontinent. Full-length rohu TLR2 (rTLR2) cDNA comprised of 2691 bp with a single open reading frame (ORF) of 2379 bp encoding a polypeptide of 792 amino acids (aa) with an estimated molecular mass of 90.74 kDa. Structurally, it comprised of one leucine-rich repeat region (LRR) each at N-terminal (LRR-NT; 44-55 aa) and C-terminal (LRR-CT; 574-590 aa), 21 LRRs in between C and N-terminal, one trans-membrane (TM) domain (595-612 aa), and one TIR domain (645-790 aa). Phylogenetically, rohu TLR2 was closely related to common carp and exhibited significant similarity (93.1%) and identity (88.1%) in their amino acids. During embryogenesis, rTLR2 expression was detected as early as ∼7 h post fertilization indicating its importance in embryonic innate immune defense system in fish. Basal expression analysis of rTLR2 showed its constitutive expression in all the tissues examined, highest was in the spleen and the lowest was in the eye. Inductive expression of TLR2 was observed following zymosan, PGN and LTA exposure and Streptococcus uberis and Edwardsiella tarda infections. Expression of immunoregulatory cytokine interleukin (IL)-8, in various organs was significantly enhanced by ligands exposure and bacterial infections, and was correlated with inductive expression of TLR2. In vitro studies showed that PGN treatment induced TLR2, MyD88 and TRAF6 (TNF receptor associated factor 6) expression, NF-κB (nuclear factor kappa B

  20. Inductive expression of toll-like receptor 5 (TLR5) and associated downstream signaling molecules following ligand exposure and bacterial infection in the Indian major carp, mrigal (Cirrhinus mrigala).

    PubMed

    Basu, M; Swain, B; Maiti, N K; Routray, P; Samanta, M

    2012-01-01

    Toll-like receptors (TLRs) are one of the key components of innate immunity. Among various types of TLRs, TLR5 is involved in recognizing bacterial flagellin and after binding, it triggers myeloid differentiation primary response gene 88 (MyD88)-dependent signaling pathway to induce pro-inflammatory cytokines. In this report, we analyzed the expression profile of TLR5 and its associated downstream signaling molecules like MyD88 and tumor necrosis factor (TNF) receptor-associated factor (TRAF) 6 in the Indian major carp (IMC), mrigal (Cirrhinus mrigala) which is highly commercially important fish species in the Indian subcontinent. Ontogeny analysis of TLR5, MyD88 and TRAF6 revealed constitutive expression of these genes in all embryonic developmental stages, and highlighted the importance of embryonic innate immune defense system in fish. Tissue specific expression analysis of these genes by quantitative real-time PCR (qRT-PCR) revealed their wide distribution in various organs and tissues; highest expression of TLR5 and MyD88 was in liver and TRAF6 was in kidney. Modulation of TLR5, MyD88 and TRAF6 gene expression, and the induction of interleukin (IL)-8 and TNF-α were analyzed in various organs by qRT-PCR following flagellin stimulation, and Aeromonas hydrophila and Edwardsiella tarda infection. In the treated fish, majority of the tested tissues exhibited significant induction of these genes, although with varied intensity among the tissues and with the types of treatments. Among the examined tissues, a significant relationship of TLR5 induction, MyD88 and TRAF6 up-regulation, and enhanced expression of IL-8 and TNF-α gene transcripts was observed in the blood and intestine of both flagellin stimulated and bacteria infected fish. These findings may indicate the involvement of TLR5 in inducing IL-8 and TNF-α, and suggest the important role of TLR5 in augmenting innate immunity in fish in response to pathogenic invasion. This study will enrich the information

  1. Toll-like receptors and liver disease.

    PubMed

    Kesar, Vivek; Odin, Joseph A

    2014-02-01

    Toll-like receptors (TLRs) are pattern recognition receptors that play an important role in host defence by recognizing pathogen-associated molecular patterns (PAMP). Recent studies indicate that TLR signalling plays an important role in progression of chronic liver diseases. Ongoing clinical trials suggest that therapeutic manipulation of TLR pathways may offer novel means of reversing chronic liver diseases. Upon activation by their respective ligands, TLRs initiate an intracellular pro-inflammatory/anti-inflammatory signalling cascade via recruitment of various adaptor proteins. TLR associated signalling pathways are tightly regulated to keep a check on inappropriate production of pro-inflammatory cytokines and interferons thereby preventing various autoimmune and inflammatory processes. Herein, we review the current state of knowledge of hepatic distribution, signalling pathways and therapeutic modulation of TLRs in chronic liver diseases. PMID:24118797

  2. Novel drugs targeting Toll-like receptors for antiviral therapy

    PubMed Central

    Patel, Mira C; Shirey, Kari Ann; Pletneva, Lioubov M; Boukhvalova, Marina S; Garzino-Demo, Alfredo; Vogel, Stefanie N; Blanco, Jorge CG

    2014-01-01

    Toll-like receptors (TLRs) are sentinel receptors of the host innate immune system that recognize conserved ‘pathogen-associated molecular patterns’ of invading microbes, including viruses. The activation of TLRs establishes antiviral innate immune responses and coordinates the development of long-lasting adaptive immunity in order to control viral pathogenesis. However, microbe-induced damage to host tissues may release ‘danger-associated molecular patterns’ that also activate TLRs, leading to an overexuberant inflammatory response and, ultimately, to tissue damage. Thus, TLRs have proven to be promising targets as therapeutics for the treatment of viral infections that result in inflammatory damage or as adjuvants in order to enhance the efficacy of vaccines. Here, we explore recent advances in TLR biology with a focus on novel drugs that target TLRs (agonists and antagonists) for antiviral therapy. PMID:25620999

  3. Unique features of chicken Toll-like receptors.

    PubMed

    Keestra, A Marijke; de Zoete, Marcel R; Bouwman, Lieneke I; Vaezirad, Mahdi M; van Putten, Jos P M

    2013-11-01

    Toll-like receptors (TLRs) are a major class of innate immune pattern recognition receptors that have a key role in immune homeostasis and the defense against infections. The research explosion that followed the discovery of TLRs more than a decade ago has boosted fundamental knowledge on the function of the immune system and the resistance against disease, providing a rational for clinical modulation of the immune response. In addition, the conserved nature of the ancient TLR system throughout the animal kingdom has enabled a comparative biology approach to understand the evolution, structural architecture, and function of TLRs. In the present review we focus on TLR biology in the avian species, and, especially, on the unique functional properties of the chicken TLR repertoire. PMID:23628643

  4. A Novel Toll-Like Receptor 9 Agonist, MGN1703, Enhances HIV-1 Transcription and NK Cell-Mediated Inhibition of HIV-1-Infected Autologous CD4+ T Cells

    PubMed Central

    Nissen, Sara Konstantin; Rasmussen, Thomas A.; Østergaard, Lars; Denton, Paul W.; Søgaard, Ole Schmeltz

    2016-01-01

    ABSTRACT Toll-like receptor (TLR) agonists are potent enhancers of innate antiviral immunity and may also reverse HIV-1 latency. Therefore, TLR agonists have a potential role in the context of a “shock-and-kill” approach to eradicate HIV-1. Our extensive preclinical evaluation suggests that a novel TLR9 agonist, MGN1703, may indeed perform both functions in an HIV-1 eradication trial. Peripheral blood mononuclear cells (PBMCs) from aviremic HIV-1-infected donors on antiretroviral therapy (ART) that were incubated with MGN1703 ex vivo exhibited increased secretion of interferon alpha (IFN-α) (P = 0.005) and CXCL10 (P = 0.0005) in culture supernatants. Within the incubated PBMC pool, there were higher proportions of CD69-positive CD56dim CD16+ NK cells (P = 0.001) as well as higher proportions of CD107a-positive (P = 0.002) and IFN-γ-producing (P = 0.038) NK cells. Incubation with MGN1703 also increased the proportions of CD69-expressing CD4+ and CD8+ T cells. Furthermore, CD4+ T cells within the pool of MGN1703-incubated PBMCs showed enhanced levels of unspliced HIV-1 RNA (P = 0.036). Importantly, MGN1703 increased the capacity of NK cells to inhibit virus spread within a culture of autologous CD4+ T cells assessed by using an HIV-1 p24 enzyme-linked immunosorbent assay (ELISA) (P = 0.03). In conclusion, we show that MGN1703 induced strong antiviral innate immune responses, enhanced HIV-1 transcription, and boosted NK cell-mediated suppression of HIV-1 infection in autologous CD4+ T cells. These findings support clinical testing of MGN1703 in HIV-1 eradication trials. IMPORTANCE We demonstrate that MGN1703 (a TLR9 agonist currently undergoing phase 3 clinical testing for the treatment of metastatic colorectal cancer) induces potent antiviral responses in immune effector cells from HIV-1-infected individuals on suppressive antiretroviral therapy. The significantly improved safety and tolerability profiles of MGN1703 versus TLR9 agonists of the Cp

  5. 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...

  6. Chapter 3. Toll-like receptors (TLRs) in Brain Abscess

    PubMed Central

    Esen, Nilufer; Kielian, Tammy

    2014-01-01

    Brain abscesses arise from a localized parenchymal infection, typically elicited by pyogenic bacteria such as S. aureus. Despite improvements in detection and treatment strategies, brain abscesses continue to occur, with an increased prevalence in developing countries and immune compromised patients. Adding to the seriousness of these infections is the recent emergence of antibiotic-resistant strains of bacteria, which are becoming more commonly associated with brain abscesses. Recent studies using a mouse experimental brain abscess model have revealed a complex role for Toll-like receptors (TLRs) in disease pathogenesis. Interestingly, TLR2 has limited impact on the innate immune response during the acute stage of brain abscess formation induced by S. aureus but influences adaptive immunity. In contrast, mice deficient in MyD88, a central adaptor molecule for the majority of TLRs in addition to the IL-1R and IL-18R, demonstrate severe defects in innate immunity coupled with exaggerated tissue destruction. It is envisioned that understanding the roles for TLRs in both resident CNS glia as well as infiltrating immune cells will provide insights as to how the immune response to bacterial infection can be tailored to achieve effective pathogen destruction without inducing excessive bystander damage of surrounding non-infected brain parenchyma. A discussion of recent findings in this field is presented along with outstanding questions and the concept of a pathogen-necrosis-autoantigen triad for the amplification for TLR signaling is introduced. PMID:19688327

  7. Essential Roles of Toll-Like Receptors in Atherosclerosis.

    PubMed

    Lin, Juntang; Kakkar, Vijay; Lu, Xinjie

    2016-01-01

    Atherosclerosis is driven by inflammation with an involvement of innate and adaptive immune responses. Toll-like receptors, the well-defined pattern recognition receptors of the immune system, play a central role in macrophage activation. Toll-like receptors recognize pathogen-associated molecular patterns expressed by a wide range of infectious agents and provide a strong link between local innate and adaptive immunity. Activation of these receptors triggers an intracellular signaling cascade mediated through myeloid differentiation factor 88 or toll/interleukin-1 receptor-domain-containing adapter-inducing interferon-β, leading to the secretion of proand anti-inflammatory cytokines. Engagement of Toll-like receptors with their ligands induces leukocyte recruitment and enhances matrix metalloproteinase expression within atherosclerotic lesions. Recently certain Toll-like receptors have shown a protective role in atherosclerosis. TLRs, therefore, represent an important link between inflammation and atheroma, making them attractive targets for the treatment of atherosclerosis. This review will briefly describe the general biological structure and potential roles of Toll-like receptors as therapeutic targets for the treatment of atherosclerosis and highlight the potential challenges on Toll-like receptor- based therapy in cardiovascular disease. PMID:26639096

  8. Constraint and Adaptation in newt Toll-Like Receptor Genes

    PubMed Central

    Babik, Wiesław; Dudek, Katarzyna; Fijarczyk, Anna; Pabijan, Maciej; Stuglik, Michał; Szkotak, Rafał; Zieliński, Piotr

    2015-01-01

    Acute die-offs of amphibian populations worldwide have been linked to the emergence of viral and fungal diseases. Inter and intraspecific immunogenetic differences may influence the outcome of infection. Toll-like receptors (TLRs) are an essential component of innate immunity and also prime acquired defenses. We report the first comprehensive assessment of TLR gene variation for urodele amphibians. The Lissotriton newt TLR repertoire includes representatives of 13 families and is compositionally most similar to that of the anuran Xenopus. Both ancient and recent gene duplications have occurred in urodeles, bringing the total number of TLR genes to at least 21. Purifying selection has predominated the evolution of newt TLRs in both long (∼70 Ma) and medium (∼18 Ma) timescales. However, we find evidence for both purifying and positive selection acting on TLRs in two recently diverged (2–5 Ma) allopatric evolutionary lineages (Lissotriton montandoni and L. vulgaris graecus). Overall, both forms of selection have been stronger in L. v. graecus, while constraint on most TLR genes in L. montandoni appears relaxed. The differences in selection regimes are unlikely to be biased by demographic effects because these were controlled by means of a historical demographic model derived from an independent data set of 62 loci. We infer that TLR genes undergo distinct trajectories of adaptive evolution in closely related amphibian lineages, highlight the potential of TLRs to capture the signatures of different assemblages of pathogenic microorganisms, and suggest differences between lineages in the relative roles of innate and acquired immunity. PMID:25480684

  9. 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

  10. The Role of Toll-Like Receptors in Hematopoietic Malignancies

    PubMed Central

    Monlish, Darlene A.; Bhatt, Sima T.; Schuettpelz, Laura G.

    2016-01-01

    Toll-like receptors (TLRs) are a family of pattern recognition receptors that shape the innate immune system by identifying pathogen-associated molecular patterns and host-derived damage-associated molecular patterns. TLRs are widely expressed on both immune cells and non-immune cells, including hematopoietic stem and progenitor cells, effector immune cell populations, and endothelial cells. In addition to their well-known role in the innate immune response to acute infection or injury, accumulating evidence supports a role for TLRs in the development of hematopoietic and other malignancies. Several hematopoietic disorders, including lymphoproliferative disorders and myelodysplastic syndromes, which possess a high risk of transformation to leukemia, have been linked to aberrant TLR signaling. Furthermore, activation of TLRs leads to the induction of a number of proinflammatory cytokines and chemokines, which can promote tumorigenesis by driving cell proliferation and migration and providing a favorable microenvironment for tumor cells. Beyond hematopoietic malignancies, the upregulation of a number of TLRs has been linked to promoting tumor cell survival, proliferation, and metastasis in a variety of cancers, including those of the colon, breast, and lung. This review focuses on the contribution of TLRs to hematopoietic malignancies, highlighting the known direct and indirect effects of TLR signaling on tumor cells and their microenvironment. In addition, the utility of TLR agonists and antagonists as potential therapeutics in the treatment of hematopoietic malignancies is discussed. PMID:27733853

  11. Toll-like receptor 4 limits transmission of Bordetella bronchiseptica.

    PubMed

    Rolin, Olivier; Smallridge, Will; Henry, Michael; Goodfield, Laura; Place, David; Harvill, Eric T

    2014-01-01

    Transmission of pathogens has been notoriously difficult to study under laboratory conditions leaving knowledge gaps regarding how bacterial factors and host immune components affect the spread of infections between hosts. We describe the development of a mouse model of transmission of a natural pathogen, Bordetella bronchiseptica, and its use to assess the impact of host immune functions. Although B. bronchiseptica transmits poorly between wild-type mice and mice lacking other immune components, it transmits efficiently between mice deficient in Toll-Like Receptor 4 (TLR4). TLR4-mutant mice were more susceptible to initial colonization, and poorly controlled pathogen growth and shedding. Heavy neutrophil infiltration distinguished TLR4-deficient responses, and neutrophil depletion did not affect respiratory CFU load, but decreased bacterial shedding. The effect of TLR4 response on transmission may explain the extensive variation in TLR4 agonist potency observed among closely related subspecies of Bordetella. This transmission model will enable mechanistic studies of how pathogens spread from one host to another, the defining feature of infectious disease.

  12. Microcirculatory detection of Toll-like receptor 4 in rat pancreas and intestine.

    PubMed

    Li, Yuan; Zhou, Zong-Guang; Zhang, Jie; Chen, You-Dai; Li, Hong-Guang; Gao, Hong-Kai; Wang, Rong; Hu, Ting-Ze

    2006-01-01

    This paper was aimed to detect Toll-like receptor 4 (TLR4) microcirculatory expression and localization in rat pancreas and intestine. Acute pancreatitis (AP) was induced by twice injections of cerulein (20 mug in total) and acute necrotizing pancreatitis (ANP) was induced by intraductal injection of 5% taurocholate (1 ml/kg.bw). Reverse transcription polymerase chain reaction (RT-PCR) and immunohistochemistry (IHC) were used to detect and localize TLR4 in the pancreas and intestine. Results showed that RT-PCR of RNA isolated from pancreatic and intestinal tissue yielded the predicted amplicon for TLR4; IHC analysis localized TLR4 expression to the endothelium of pancreatic arteriole, venule, acinar capillary network and sinusoidal capillary of endocrine islet; TLR4 expression in intestine was principally in the microvascular endothelium and leucocytes within the mucosa lamina propria. TLR4 staining in intestine was more intense in taurocholate-induced pancreatitis (TIP) than that in cerulein-induced pancreatitis (CIP). In conclusion, TLR4 could be detected in the pancreatic and intestinal microcirculation, suggesting TLR4 involved in the microcirculatory impairment in AP; the more intense intestinal TLR4 expression in TIP suggests a potential risk for secondary infection.

  13. MAP1S Protein Regulates the Phagocytosis of Bacteria and Toll-like Receptor (TLR) Signaling.

    PubMed

    Shi, Ming; Zhang, Yifan; Liu, Leyuan; Zhang, Tingting; Han, Fang; Cleveland, Joseph; Wang, Fen; McKeehan, Wallace L; Li, Yu; Zhang, Dekai

    2016-01-15

    Phagocytosis is a critical cellular process for innate immune defense against microbial infection. The regulation of phagocytosis process is complex and has not been well defined. An intracellular molecule might regulate cell surface-initiated phagocytosis, but the underlying molecular mechanism is poorly understood (1). In this study, we found that microtubule-associated protein 1S (MAP1S), a protein identified recently that is involved in autophagy (2), is expressed primarily in macrophages. MAP1S-deficient macrophages are impaired in the phagocytosis of bacteria. Furthermore, we demonstrate that MAP1S interacts directly with MyD88, a key adaptor of Toll-like receptors (TLRs), upon TLR activation and affects the TLR signaling pathway. Intriguingly, we also observe that, upon TLR activation, MyD88 participates in autophagy processing in a MAP1S-dependent manner by co-localizing with MAP1 light chain 3 (MAP1-LC3 or LC3). Therefore, we reveal that an intracellular autophagy-related molecule of MAP1S controls bacterial phagocytosis through TLR signaling.

  14. Differential Toll-Like Receptor-Signalling of Burkholderia pseudomallei Lipopolysaccharide in Murine and Human Models

    PubMed Central

    Weehuizen, Tassili A. F.; Prior, Joann L.; van der Vaart, Thomas W.; Ngugi, Sarah A.; Nepogodiev, Sergey A.; Field, Robert A.; Kager, Liesbeth M.; van ‘t Veer, Cornelis; de Vos, Alex F.; Wiersinga, W. Joost

    2015-01-01

    The Gram-negative bacterium Burkholderia pseudomallei causes melioidosis and is a CDC category B bioterrorism agent. Toll-like receptor (TLR)-2 impairs host defense during pulmonary B.pseudomallei infection while TLR4 only has limited impact. We investigated the role of TLRs in B.pseudomallei-lipopolysaccharide (LPS) induced inflammation. Purified B.pseudomallei-LPS activated only TLR2-transfected-HEK-cells during short stimulation but both HEK-TLR2 and HEK-TLR4-cells after 24 h. In human blood, an additive effect of TLR2 on TLR4-mediated signalling induced by B.pseudomallei-LPS was observed. In contrast, murine peritoneal macrophages recognized B.pseudomallei-LPS solely through TLR4. Intranasal inoculation of B.pseudomallei-LPS showed that both TLR4-knockout(-/-) and TLR2x4-/-, but not TLR2-/- mice, displayed diminished cytokine responses and neutrophil influx compared to wild-type controls. These data suggest that B.pseudomallei-LPS signalling occurs solely through murine TLR4, while in human models TLR2 plays an additional role, highlighting important differences between specificity of human and murine models that may have important consequences for B.pseudomallei-LPS sensing by TLRs and subsequent susceptibility to melioidosis. PMID:26689559

  15. 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...

  16. Toll-like receptors recognize distinct proteinase-resistant glycoconjugates in Campylobacter jejuni and Escherichia coli.

    PubMed

    Phongsisay, Vongsavanh; Hara, Hiromitsu; Fujimoto, Shuji

    2015-03-01

    Campylobacter jejuni causes gastroenteritis and autoimmune neuropathy Guillain-Barré syndrome. The mechanism by which C. jejuni infection results in such the hyperimmunity is not completely understood. Host immunity plays an important role in the disease pathogenesis; however, little is known how immune system recognizes this human pathogen. In this study, we report that Toll-like receptors recognize distinct proteinase K-resistant glycoconjugates in C. jejuni and Escherichia coli. Lipopolysaccharide is solely proteinase-resistant glycoconjugate in E. coli. In contrast, C. jejuni possesses at least five different components that are resistant to proteinase digestion and are capable of inducing NF-κB activation through TLR2 and TLR4. Possession of multiple activators of Toll-like receptors may be the unique strategy of C. jejuni to trigger hyperimmunity.

  17. Hepatitis B virus genome replication triggers toll-like receptor 3-dependent interferon responses in the absence of hepatitis B surface antigen.

    PubMed

    Real, Catherine Isabell; Lu, Mengji; Liu, Jia; Huang, Xuan; Trippler, Martin; Hossbach, Markus; Deckert, Jochen; Jahn-Hofmann, Kerstin; Ickenstein, Ludger Markus; John, Matthias Johannes; Gibbert, Kathrin; Dittmer, Ulf; Vornlocher, Hans-Peter; Schirmbeck, Reinhold; Gerken, Guido; Schlaak, Joerg Friedrich; Broering, Ruth

    2016-01-01

    The hepatitis B virus (HBV) has been described as stealth virus subverting immune responses initially upon infection. Impaired toll-like receptor signaling by the HBV surface antigen (HBsAg) attenuates immune responses to facilitate chronic infection. This implies that HBV replication may trigger host innate immune responses in the absence of HBsAg. Here we tested this hypothesis, using highly replicative transgenic mouse models. An HBV replication-dependent expression of antiviral genes was exclusively induced in HBsAg-deficient mice. These interferon responses attributed to toll-like receptor 3 (TLR3)-activated Kupffer and liver sinusoidal endothelial cells and further controlled the HBV genome replication. However, activation of TLR3 with exogenous ligands indicated additional HBs-independent immune evasion events. Our data demonstrate that in the absence of HBsAg, hepatic HBV replication leads to Tlr3-dependent interferon responses in non-parenchymal liver cells. We hypothesize that HBsAg is a major HBV-mediated evasion mechanism controlling endogenous antiviral responses in the liver. Eradication of HBsAg as a therapeutic goal might facilitate the induction of endogenous antiviral immune responses in patients chronically infected with HBV. PMID:27121087

  18. Hepatitis B virus genome replication triggers toll-like receptor 3-dependent interferon responses in the absence of hepatitis B surface antigen

    PubMed Central

    Real, Catherine Isabell; Lu, Mengji; Liu, Jia; Huang, Xuan; Trippler, Martin; Hossbach, Markus; Deckert, Jochen; Jahn-Hofmann, Kerstin; Ickenstein, Ludger Markus; John, Matthias Johannes; Gibbert, Kathrin; Dittmer, Ulf; Vornlocher, Hans-Peter; Schirmbeck, Reinhold; Gerken, Guido; Schlaak, Joerg Friedrich; Broering, Ruth

    2016-01-01

    The hepatitis B virus (HBV) has been described as stealth virus subverting immune responses initially upon infection. Impaired toll-like receptor signaling by the HBV surface antigen (HBsAg) attenuates immune responses to facilitate chronic infection. This implies that HBV replication may trigger host innate immune responses in the absence of HBsAg. Here we tested this hypothesis, using highly replicative transgenic mouse models. An HBV replication-dependent expression of antiviral genes was exclusively induced in HBsAg-deficient mice. These interferon responses attributed to toll-like receptor 3 (TLR3)-activated Kupffer and liver sinusoidal endothelial cells and further controlled the HBV genome replication. However, activation of TLR3 with exogenous ligands indicated additional HBs-independent immune evasion events. Our data demonstrate that in the absence of HBsAg, hepatic HBV replication leads to Tlr3-dependent interferon responses in non-parenchymal liver cells. We hypothesize that HBsAg is a major HBV-mediated evasion mechanism controlling endogenous antiviral responses in the liver. Eradication of HBsAg as a therapeutic goal might facilitate the induction of endogenous antiviral immune responses in patients chronically infected with HBV. PMID:27121087

  19. Systemic cancer immunotherapy with Toll-like receptor 7 agonists

    PubMed Central

    Hotz, Christian; Bourquin, Carole

    2012-01-01

    Toll-like receptor (TLR) 7 agonists represent a promising strategy for the immunotherapy of cancer. We have recently investigated the influence of TLR tolerance on the efficacy of systemic tumor treatment with TLR7 ligands. We propose that considering the kinetics of receptor sensitivity highly improves the outcome of cancer immunotherapy. PMID:22720251

  20. Diverse Toll-like receptors mediate cytokine production by Fusobacterium nucleatum and Aggregatibacter actinomycetemcomitans in macrophages.

    PubMed

    Park, Se-Ra; Kim, Dong-Jae; Han, Seung-Hyun; Kang, Min-Jung; Lee, Jun-Young; Jeong, Yu-Jin; Lee, Sang-Jin; Kim, Tae-Hyoun; Ahn, Sang-Gun; Yoon, Jung-Hoon; Park, Jong-Hwan

    2014-05-01

    Toll-like receptors (TLRs) orchestrate a repertoire of immune responses in macrophages against various pathogens. Fusobacterium nucleatum and Aggregatibacter actinomycetemcomitans are two important periodontal pathogens. In the present study, we investigated TLR signaling regulating cytokine production of macrophages in response to F. nucleatum and A. actinomycetemcomitans. TLR2 and TLR4 are redundant in the production of cytokines (interleukin-6 [IL-6] and tumor necrosis factor alpha [TNF-α]) in F. nucleatum- and A. actinomycetemcomitans-infected macrophages. The production of cytokines by macrophages in response to F. nucleatum and A. actinomycetemcomitans infection was impaired in MyD88-deficient macrophages. Moreover, cytokine concentrations were lower in MyD88-deficient macrophages than in TLR2/TLR4 (TLR2/4) double-deficient cells. An endosomal TLR inhibitor, chloroquine, reduced cytokine production in TLR2/4-deficient macrophages in response to F. nucleatum and A. actinomycetemcomitans, and DNA from F. nucleatum or A. actinomycetemcomitans induced IL-6 production in bone marrow-derived macrophages (BMDMs), which was abolished by chloroquine. Western blot analysis revealed that TLR2/4 and MyD88 were required for optimal activation of NF-κB and mitogen-activated protein kinases (MAPKs) in macrophages in response to F. nucleatum and A. actinomycetemcomitans, with different kinetics. An inhibitor assay showed that NF-κB and all MAPKs (p38, extracellular signal-regulated kinase [ERK], and Jun N-terminal protein kinase [JNK]) mediate F. nucleatum-induced production of cytokines in macrophages, whereas NF-κB and p38, but not ERK and JNK, are involved in A. actinomycetemcomitans-mediated cytokine production. These findings suggest that multiple TLRs may participate in the cytokine production of macrophages against periodontal bacteria.

  1. 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.

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

    PubMed

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

    2012-09-01

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

  3. Therapeutic potential of Toll-like receptor 9 activation.

    PubMed

    Krieg, Arthur M

    2006-06-01

    In the decade since the discovery that mouse B cells respond to certain unmethylated CpG dinucleotides in bacterial DNA, a specific receptor for these 'CpG motifs' has been identified, Toll-like receptor 9 (TLR9), and a new approach to immunotherapy has moved into the clinic based on the use of synthetic oligodeoxynucleotides (ODN) as TLR9 agonists. This review highlights the current understanding of the mechanism of action of these CpG ODN, and provides an overview of the preclinical data and early human clinical trial results using these drugs to improve vaccines and treat cancer, infectious disease and allergy/asthma. PMID:16763660

  4. Application potential of toll-like receptors in cancer immunotherapy

    PubMed Central

    Shi, Ming; Chen, Xi; Ye, Kangruo; Yao, Yuanfei; Li, Yu

    2016-01-01

    Abstract Toll-like receptors (TLRs), as the most important pattern recognition receptors in innate immunity, play a pivotal role in inducing immune response through recognition of microbial invaders or specific agonists. Recent studies have suggested that TLRs could serve as important regulators in the development of a variety of cancer. However, increasing evidences have shown that TLRs may display quite opposite outcomes in cancer development. Although several potential therapeutic Toll-like receptor ligands have been found, the mechanism and therapy prospect of TLRs in cancer development has to be further elucidated to accelerate the clinical application. By performing a systematic review of the present findings on TLRs in cancer immunology, we attempted to evaluate the therapeutic potential of TLRs in cancer therapy and elucidate the potential mechanism of cancer progress regulated by TLR signaling and the reported targets on TLRs for clinical application. An electronic databases search was conducted in PubMed, Chinese Scientific Journal Database, and Chinese Biomedical Literature Database from their inception to February 1, 2016. The following keywords were used to search the databases: Toll-like receptors, cancer therapy, therapeutic target, innate immunity. Of 244 studies that were identified, 97 nonrelevant studies were excluded. In total, 147 full-text articles were assessed, and from these, 54 were excluded as they did not provide complete key information. Thus, 93 studies were considered eligible and included in the analysis. According to the data from the included trials, 14 TLR ligands (77.8%) from 82 studies have been demonstrated to display antitumor property in various cancers, whereas 4 ligands (22.2%) from 11 studies promote tumors. Among them, only 3 TLR ligands have been approved for cancer therapy, and 9 ligands were in clinical trials. In addition, the potential mechanism of recently reported targets on TLRs for clinical application was also

  5. The role of toll-like receptors 2 and 4 in the pathogenesis of feline pyometra.

    PubMed

    Jursza, E; Kowalewski, M P; Boos, A; Skarzynski, D J; Socha, P; Siemieniuch, M J

    2015-03-01

    Pyometra is the most common uterine disease in queens. To protect itself from infection, the female reproductive tract possesses several immune mechanisms that are based on germline-encoded pattern recognition receptors (toll-like receptors [TLRs]). The aim of our study was to examine endometrial immunolocalization of TLR2/4, study the influence of lipopolysaccharide (LPS) and tumor necrosis factor (TNF) α on messenger RNA expression of both receptors in pyometric queens, and compare these patterns between estrous cycling queens and those hormonally treated with medroxyprogesterone acetate (MPA). Thirty-six queens, ranging in age from 7 months to 11 years, were allocated into seven groups (anestrus, estrus, mid-diestrus and late diestrus, short-term and long-term hormonally treated queens, and pyometric queens). At the messenger RNA level, the real-time polymerase chain reaction was applied, whereas at the TLR2/4 protein level, the expression was tested by immunohistochemistry. In queens at estrus, gene expression of TLR2 was upregulated after stimulation of endometrial explants by TNF (P < 0.001) and by TNF together with the LPS (P < 0.01). Moreover, gene expression of TLR2 was significantly upregulated after stimulation by TNF (P < 0.001) and LPS (P < 0.01) explants derived from queens that had been long-term hormonally treated with MPA. Endometrial gene expression of TLR4 was significantly upregulated after incubation of explants with TNF (P < 0.001) in queens at estrus and with LPS (P < 0.05) in queens short-term hormonally treated with MPA. Immunolocalization reported that TLR2/4 receptors are mainly localized in the surface and glandular epithelia. These data show that short-term and especially long-term administration of progesterone derivatives impairs TLRs in the endometrial epithelium, presumably enabling pathogens to break through this first natural barrier and thereby increase the risk of pyometra development. PMID:25481489

  6. Antiinfective applications of toll-like receptor 9 agonists.

    PubMed

    Krieg, Arthur M

    2007-07-01

    The innate immune system detects pathogens by the presence of highly conserved pathogen-expressed molecules, which trigger host immune defenses. Toll-like receptor (TLR) 9 detects unmethylated CpG dinucleotides in bacterial or viral DNA, and can be stimulated for therapeutic applications with synthetic oligodeoxynucleotides containing immune stimulatory "CpG motifs." TLR9 activation induces both innate and adaptive immunity. The TLR9-induced innate immune activation can be applied in the prevention or treatment of infectious diseases, and the adaptive immune-enhancing effects can be harnessed for improving vaccines. This article highlights the current understanding of the mechanism of action of CpG oligodeoxynucleotides, and provides an overview of the preclinical data and early human clinical trial results, applying these TLR9 agonists in the field of infectious diseases. PMID:17607015

  7. Toll-like receptors are key players in neurodegeneration

    PubMed Central

    Arroyo, Daniela S.; Soria, Javier A.; Gaviglio, Emilia A.; Rodriguez-Galan, Maria C.; Iribarren, Pablo

    2011-01-01

    The activation of innate immune response is initiated by engagement of pattern-recognition receptors (PPRs), such as Toll-like receptors (TLRs). These receptors are expressed in peripheral leukocytes and in many cell types in the central nervous system (CNS). The expression of TLRs in CNS was mainly studied in astrocytes and microglial cells. However, new evidence indicates that these receptors may play an important role in neuronal homeostasis. The expression of TLRs in the CNS is variable and can be modulated by multiple factors, including pro-inflammatory molecules, which are elevated in neurodegenerative diseases and can increase the expression of TLRs in CNS cells. Moreover, activation of TLRs induces the release of pro-inflammatory cytokines. Therefore, TLRs have been shown to play a role in several aspects of neurodegenerative diseases. Here we will discuss results reported in the recent literature concerning the participation of TLRs in neurodegenerative diseases. PMID:21616174

  8. 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.

  9. 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.

  10. Role of toll-like receptors and inflammation in adrenal gland insufficiency.

    PubMed

    Kanczkowski, Waldemar; Zacharowski, Kai; Bornstein, Stefan R

    2010-01-01

    Adrenal gland insufficiency - the clinical manifestation of deficient production or action of adrenal steroids - is a life-threatening disorder. Among many factors which can predispose to primary adrenal failure, an autoimmune adrenalitis and infectious agents play a major role. The initial host defense against bacterial infections is executed primarily by the pattern recognition receptors, e.g. Toll-like receptors (TLRs), expressed in cells from the innate immune system. Upon activation, TLRs have been found to regulate various levels of innate and adaptive immunity as well as control tissue inflammation. TLRs are implicated in adrenal cell turnover and steroidogenesis during inflammation. Therefore, TLRs play a crucial role in the activation of adrenal inflammation mediating adrenal gland dysfunction during septicemia.

  11. 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.

  12. The Role of Toll-Like Receptor 4 in Infectious and Noninfectious Inflammation

    PubMed Central

    Molteni, Monica; Gemma, Sabrina

    2016-01-01

    Toll-like receptor 4 (TLR4) belongs to the family of pattern recognition receptors (PRRs). They are highly conserved receptors that recognize conserved pathogen-associated molecular patterns (PAMPs), thus representing the first line of defense against infections. TLR4 has been long recognized as the sensing receptor for gram-negative lipopolysaccharide (LPS). In addition, it also binds endogenous molecules produced as a result of tissue injury. Hence, TLR4 represents a key receptor on which both infectious and noninfectious stimuli converge to induce a proinflammatory response. TLR4-mediated inflammation, triggered by exogenous or endogenous ligands, is also involved in several acute and chronic diseases, having a pivotal role as amplifier of the inflammatory response. This review focuses on the research progress about the role of TLR4 activation in infectious and noninfectious (e.g., sterile) inflammation and the effects of TLR4 signaling in some pathological conditions. PMID:27293318

  13. CPG-7909 (PF-3512676, ProMune): toll-like receptor-9 agonist in cancer therapy.

    PubMed

    Murad, Yanal M; Clay, Timothy M; Lyerly, H Kim; Morse, Michael A

    2007-08-01

    Stimulation of toll-like receptor (TLR)9 activates human plasmacytoid dendritic cells and B cells, and induces potent innate immune responses in preclinical tumor models and in patients. CpG oligodeoxynucleotides (ODNs) are TLR9 agonists that show promising results as vaccine adjuvants and in the treatment of cancers, infections, asthma and allergy. PF-3512676 (ProMune) was developed as a TLR9 agonist for the treatment of cancer as monotherapy and as an adjuvant in combination with chemo- and immunotherapy. Phase I and II trials have tested this drug in several hematopoietic and solid tumors. Pfizer has initiated Phase III trials to test PF-3512676 in combination with standard chemotherapy for non-small-cell lung cancer. PMID:17696823

  14. Innate Immune Sensing by Toll-like Receptors in Newborns and the Elderly

    PubMed Central

    Kollmann, Tobias R.; Levy, Ofer; Montgomery, Ruth R.; Goriely, Stanislas

    2012-01-01

    Summary Given the "inborn" nature of the innate immune system, it is surprising to find that innate immune function does in fact change with age. Similar patterns of distinct Toll-like receptor (TLR)-mediated immune responses come to light when one contrasts innate immune development at the beginning of life with that toward the end of life. Importantly, these developmental patterns of innate cytokine responses correlate with clinical patterns of susceptibility to disease: A heightened risk of suffering from excessive inflammation is often detected in prematurely born infants, disappears over the first few months of life, and reappears toward the end of life. In addition, risk periods for particular infections in early life reemerge in older adults. The near-mirror-image patterns that emerge in contrasts of early versus late innate immune ontogeny emphasize changes in host-environment interactions as the underlying molecular and teleologic drivers. PMID:23159225

  15. Lipopolysaccharides Belonging to Different Salmonella Serovars Are Differentially Capable of Activating Toll-Like Receptor 4

    PubMed Central

    Spiga, Luisella; De Riu, Nicola; Delaconi, Paola; Mazzarello, Vittorio; Ganau, Giulia; Rubino, Salvatore

    2014-01-01

    Salmonella enterica subsp. enterica serovar (serotype) Abortusovis is a member of the Enterobacteriaceae. This serotype is naturally restricted to ovine species and does not infect humans. Limited information is available about the immune response of sheep to S. Abortusovis. S. Abortusovis, like Salmonella enterica subsp. enterica serovar Typhi, causes a systemic infection in which, under natural conditions, animals are not able to raise a rapid immune response. Failure to induce the appropriate response allows pathogens to reach the placenta and results in an abortion. Lipopolysaccharides (LPSs) are pathogen-associated molecular patterns (PAMPs) that are specific to bacteria and are not synthesized by the host. Toll-like receptors (TLRs) are a family of receptors that specifically recognize PAMPs. As a first step, we were able to identify the presence of Toll-like receptor 4 (TLR4) on the ovine placenta by using an immunohistochemistry technique. To our knowledge, this is the first work describing the interaction between S. Abortusovis LPS and TLR4. Experiments using an embryonic cell line (HEK293) transfected with human and ovine TLR4s showed a reduction of interleukin 8 (IL-8) production by S. Abortusovis and Salmonella enterica subsp. enterica serovar Paratyphi upon LPS stimulation compared to Salmonella enterica subsp. enterica serovar Typhimurium. Identical results were observed using heat-killed bacteria instead of LPS. Based on data obtained with TLR4 in vitro stimulation, we demonstrated that the serotype S. Abortusovis is able to successfully evade the immune system whereas S. Typhimurium and other serovars fail to do so. PMID:25135686

  16. Bacterial lipopolysaccharide induces increased expression of toll-like receptor (TLR) 4 and downstream TLR signaling molecules in bovine mammary epithelial cells

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Bovine mammary epithelial cells contribute to the innate immune response to intramammary infections by recognizing pathogens through specialized pattern recognition receptors. Toll-like receptor 4 (TLR4) is one such receptor that binds and is activated by lipopolysaccharide (LPS), a component of the...

  17. Comparative studies of Toll-like receptor signalling using zebrafish.

    PubMed

    Kanwal, Zakia; Wiegertjes, Geert F; Veneman, Wouter J; Meijer, Annemarie H; Spaink, Herman P

    2014-09-01

    Zebrafish model systems for infectious disease are increasingly used for the functional analysis of molecular pattern recognition processes. These studies benefit from the high conservation level of all innate immune factors in vertebrates. Zebrafish studies are strategically well positioned for this because of the ease of comparisons with studies in other fish species of which the immune system also has been intensively studied, but that are currently still less amendable to detailed genetic or microscopic studies. In this paper we focus on Toll-like receptor (TLR) signalling factors, which currently are the best characterized in mammalian systems. We review the knowledge on TLR signalling in the context of recent advances in zebrafish studies and discuss possibilities for future approaches that can complement studies in cell cultures and rodent models. A focus in these comparisons is the role of negative control mechanisms in immune responses that appear very important in a whole organism to keep adverse systemic responses in check. We also pay much attention to comparisons with studies in common carp that is highly related to zebrafish and that because of its large body mass can complement immune studies in zebrafish.

  18. Toll-like receptors: potential targets for lupus treatment.

    PubMed

    Wu, Yan-wei; Tang, Wei; Zuo, Jian-ping

    2015-12-01

    Systemic lupus erythematosus (SLE) is a complex autoimmune disease characterized by the loss of tolerance to self-nuclear antigens. Accumulating evidence shows that Toll-like receptors (TLRs), previously proven to be critical for host defense, are implicated in the pathogenesis of autoimmune diseases by recognition of self-molecules. Genome-wide association studies, experimental mouse models and clinical sample studies have provided evidence for the involvement of TLRs, including TLR2/4, TLR5, TLR3 and TLR7/8/9, in SLE pathogenesis. A number of downstream proteins in the TLR signaling cascade (such as MyD88, IRAKs and IFN-α) are identified as potential therapeutic targets for SLE treatment. Numerous antagonists targeting TLR signaling, including oligonucleotides, small molecular inhibitors and antibodies, are currently under preclinical studies or clinical trials for SLE treatment. Moreover, the emerging new manipulation of TLR signaling by microRNA (miRNA) regulation shows promise for the future treatment of SLE.

  19. Computational Approaches to Toll-Like Receptor 4 Modulation.

    PubMed

    Billod, Jean-Marc; Lacetera, Alessandra; Guzmán-Caldentey, Joan; Martín-Santamaría, Sonsoles

    2016-01-01

    Toll-like receptor 4 (TLR4), along with its accessory protein myeloid differentiation factor 2 (MD-2), builds a heterodimeric complex that specifically recognizes lipopolysaccharides (LPS), which are present on the cell wall of Gram-negative bacteria, activating the innate immune response. Some TLR4 modulators are undergoing preclinical and clinical evaluation for the treatment of sepsis, inflammatory diseases, cancer and rheumatoid arthritis. Since the relatively recent elucidation of the X-ray crystallographic structure of the extracellular domain of TLR4, research around this fascinating receptor has risen to a new level, and thus, new perspectives have been opened. In particular, diverse computational techniques have been applied to decipher some of the basis at the atomic level regarding the mechanism of functioning and the ligand recognition processes involving the TLR4/MD-2 system at the atomic level. This review summarizes the reported molecular modeling and computational studies that have recently provided insights into the mechanism regulating the activation/inactivation of the TLR4/MD-2 system receptor and the key interactions modulating the molecular recognition process by agonist and antagonist ligands. These studies have contributed to the design and the discovery of novel small molecules with promising activity as TLR4 modulators. PMID:27483231

  20. Cathepsins are required for Toll-like receptor 9 responses

    SciTech Connect

    Matsumoto, Fumi; Saitoh, Shin-ichiroh; Fukui, Ryutaroh; Kobayashi, Toshihiko; Tanimura, Natsuko; Konno, Kazunori; Kusumoto, Yutaka; Akashi-Takamura, Sachiko; Miyake, Kensuke

    2008-03-14

    Toll-like receptors (TLR) recognize a variety of microbial products and activate defense responses. Pathogen sensing by TLR2/4 requires accessory molecules, whereas little is known about a molecule required for DNA recognition by TLR9. After endocytosis of microbes, microbial DNA is exposed and recognized by TLR9 in lysosomes. We here show that cathepsins, lysosomal cysteine proteases, are required for TLR9 responses. A cell line Ba/F3 was found to be defective in TLR9 responses despite enforced TLR9 expression. Functional cloning with Ba/F3 identified cathepsin B/L as a molecule required for TLR9 responses. The protease activity was essential for the complementing effect. TLR9 responses were also conferred by cathepsin S or F, but not by cathepsin H. TLR9-dependent B cell proliferation and CD86 upregulation were apparently downregulated by cathepsin B/L inhibitors. Cathepsin B inhibitor downregulated interaction of CpG-B with TLR9 in 293T cells. These results suggest roles for cathepsins in DNA recognition by TLR9.

  1. Allergens and Activation of the Toll-Like Receptor Response.

    PubMed

    Monie, Tom P; Bryant, Clare E

    2016-01-01

    Pattern recognition receptors (PRRs) provide a crucial function in the detection of exogenous and endogenous danger signals. The Toll-like receptors (TLRs) were the first family of PRRs to be discovered and have been extensively studied since. Whilst TLRs remain the best characterized family of PRRs there is still much to be learnt about their mode of activation and the mechanisms of signal transduction they employ. Much of our understanding of these processes has been gathered through the use of cell based signaling assays utilizing specific gene-reporters or cytokine secretion based readouts. More recently it has become apparent that the repertoire of ligands recognized by these receptors may be wider than originally assumed and that their activation may be sensitized, or at least modulated by the presence of common household allergens such as the cat dander protein Fel d 1, or the house dust mite allergen Der p 2. In this chapter we provide an overview of the cell culture and stimulation processes required to study TLR signaling in HEK293 based assays and in bone marrow-derived macrophages. PMID:26803639

  2. A Toll-like receptor in horseshoe crabs.

    PubMed

    Inamori, Kei-ichiro; Ariki, Shigeru; Kawabata, Shun-ichiro

    2004-04-01

    Non-self-recognition of invading microbes relies on the pattern-recognition of pathogen-associated molecular patterns (PAMPs) derived from microbial cell-wall components. Insects and mammals conserve a signaling pathway of the innate immune system through cell-surface receptors called Tolls and Toll-like receptors (TLRs). Bacterial lipopolysaccharides (LPSs) are an important trigger of the horseshoe crab's innate immunity to infectious microorganisms. Horseshoe crabs' granular hemocytes respond specifically to LPS stimulation, inducing the secretion of various defense molecules from the granular hemocytes. Here, we show a cDNA which we named tToll, coding for a TLR identified from hemocytes of the horseshoe crab Tachypleus tridentatus. tToll is most closely related to Drosophila Toll in both domain architecture and overall length. Human TLRs have been suggested to contain numerous PAMP-binding insertions located in the leucine-rich repeats (LRRs) of their ectodomains. However, the LRRs of tToll contained no obvious PAMP-binding insertions. Furthermore, tToll was non-specifically expressed in horseshoe crab tissues. These observations suggest that tToll does not function as an LPS receptor on granular hemocytes.

  3. 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.

  4. Toll-like receptors: potential targets for lupus treatment

    PubMed Central

    Wu, Yan-wei; Tang, Wei; Zuo, Jian-ping

    2015-01-01

    Systemic lupus erythematosus (SLE) is a complex autoimmune disease characterized by the loss of tolerance to self-nuclear antigens. Accumulating evidence shows that Toll-like receptors (TLRs), previously proven to be critical for host defense, are implicated in the pathogenesis of autoimmune diseases by recognition of self-molecules. Genome-wide association studies, experimental mouse models and clinical sample studies have provided evidence for the involvement of TLRs, including TLR2/4, TLR5, TLR3 and TLR7/8/9, in SLE pathogenesis. A number of downstream proteins in the TLR signaling cascade (such as MyD88, IRAKs and IFN-α) are identified as potential therapeutic targets for SLE treatment. Numerous antagonists targeting TLR signaling, including oligonucleotides, small molecular inhibitors and antibodies, are currently under preclinical studies or clinical trials for SLE treatment. Moreover, the emerging new manipulation of TLR signaling by microRNA (miRNA) regulation shows promise for the future treatment of SLE. PMID:26592511

  5. Association of Toll-like receptor 2 polymorphisms with gout

    PubMed Central

    CAI, YAN; PENG, YI-HUA; TANG, ZHONG; GUO, XIAO-LAN; QING, YU-FENG; LIANG, SU-HUA; JIANG, HONG; DANG, WANG-TAI; MA, QIANG; HE, CHENG; ZHOU, JING-GUO

    2014-01-01

    Gout is the most common autoinflammatory arthritis characterized by elevated serum urate and recurrent attacks of intra-articular crystal deposition of monosodium urate (MSU) in tissues. The pathogenesis of gout has not been fully determined, although certain genetic factors are involved in the development of gout. Accumulated data suggested that MSU crystal-induced inflammation is a paradigm of innate immunity. As Toll-like receptors (TLRs) are the underlying mechanisms of the innate immune response, the present study aimed to investigate whether TLR2 polymorphisms are associated with gout. Two single-nucleotide polymorphisms (Arg677Trp and Arg753Gln, rs5743708) in TLR2 were genotyped by polymerase chain reaction-restriction fragment length polymorphism and the −196 to −174 del polymorphism was investigated using the allele-specific polymerase chain reaction in 431 individuals (215 patients with gout and 216 healthy controls). TLR2 Arg677Trp and Arg753Gln genotyping indicated that all the positive samples were of the wild-type genotype. No significant differences in genotype (χ2=1.686, P=0.430) and allele (χ2=1.430, P=0.232) frequencies of the −196 to −174 del polymorphism between the patients with gout and the control groups was observed. Our results suggested that the TLR2 Arg677Trp, Arg753Gln and the −196 to −174 del polymorphisms were not associated with susceptibility to primary gouty arthritis. PMID:24649113

  6. [The correlation study between the changes of intestinal mucosa predominant bacteria and Toll-like receptor 2, Toll-like receptor 4 gene expressions in diarrhea-predominant irritable bowel syndrome patients].

    PubMed

    Guo, W T; Liu, P; Dong, L N; Wang, J P

    2016-07-01

    Based on high throughput sequencing and PCR detection technology, this study has found out that intestinal microbial diversity was impaired and the quantities of two main bacteria flora (Bacteroidetes and Clostridium) were significantly reduced in patients with diarrhea-predominant irritable bowel syndrome (D-IBS). Meanwhile mucosal expression of toll-like receptor (TLR) 2 and TLR4 were significantly enhanced, which was inversely correlated with the reduction of Bacteroidetes and Clostridium. Thus, it suggests that D-IBS may be associated with TLR signal transduction triggered by the intestinal dysbacteriosis. PMID:27373290

  7. The Immune Response to Trypanosoma cruzi: Role of Toll-Like Receptors and Perspectives for Vaccine Development

    PubMed Central

    Rodrigues, Mauricio M.; Oliveira, Ana Carolina; Bellio, Maria

    2012-01-01

    In the past ten years, studies have shown the recognition of Trypanosoma cruzi-associated molecular patterns by members of the Toll-like receptor (TLR) family and demonstrated the crucial participation of different TLRs during the experimental infection with this parasite. In the present review, we will focus on the role of TLR-activated pathways in the modulation of both innate and acquired immune responses to T. cruzi infection, as well as discuss the state of the art of vaccine research and development against the causative agent of Chagas disease (or American trypanosomiasis). PMID:22496959

  8. Structural characterisation of Toll-like receptor 1 (TLR1) and Toll-like receptor 6 (TLR6) in elephant and harbor seals.

    PubMed

    Woodman, Sally; Gibson, Amanda J; García, Ana Rubio; Contreras, Guillermo Sanchez; Rossen, John W; Werling, Dirk; Offord, Victoria

    2016-01-01

    Pinnipeds are a diverse clade of semi-aquatic mammals, which act as key indicators of ecosystem health. Their transition from land to marine environments provides a complex microbial milieu, making them vulnerable to both aquatic and terrestrial pathogens, thereby contributing to pinniped population decline. Indeed, viral pathogens such as influenza A virus and phocine distemper virus (PDV) have been identified as the cause of several of these mass mortality events. Furthermore, bacterial infection with mammalian Brucella sp. and methicillin-resistant Staphylococcus aureus strains have also been observed in marine mammals, posing further risk to both co-habiting endangered species and public health. During these disease outbreaks, mortality rates have varied amongst different pinniped species. Analyses of innate immune receptors at the host-pathogen interface have previously identified variants which may drive these species-specific responses. Through a combination of both sequence- and structure-based methods, this study characterises members of the Toll-like receptor (TLR) 1 superfamily from both harbour and elephant seals, identifying variations which will help us to understand these species-specific innate immune responses, potentially aiding the development of specific vaccine-adjuvants for these species.

  9. Structural characterisation of Toll-like receptor 1 (TLR1) and Toll-like receptor 6 (TLR6) in elephant and harbor seals.

    PubMed

    Woodman, Sally; Gibson, Amanda J; García, Ana Rubio; Contreras, Guillermo Sanchez; Rossen, John W; Werling, Dirk; Offord, Victoria

    2016-01-01

    Pinnipeds are a diverse clade of semi-aquatic mammals, which act as key indicators of ecosystem health. Their transition from land to marine environments provides a complex microbial milieu, making them vulnerable to both aquatic and terrestrial pathogens, thereby contributing to pinniped population decline. Indeed, viral pathogens such as influenza A virus and phocine distemper virus (PDV) have been identified as the cause of several of these mass mortality events. Furthermore, bacterial infection with mammalian Brucella sp. and methicillin-resistant Staphylococcus aureus strains have also been observed in marine mammals, posing further risk to both co-habiting endangered species and public health. During these disease outbreaks, mortality rates have varied amongst different pinniped species. Analyses of innate immune receptors at the host-pathogen interface have previously identified variants which may drive these species-specific responses. Through a combination of both sequence- and structure-based methods, this study characterises members of the Toll-like receptor (TLR) 1 superfamily from both harbour and elephant seals, identifying variations which will help us to understand these species-specific innate immune responses, potentially aiding the development of specific vaccine-adjuvants for these species. PMID:26827833

  10. Deviation from major codons in the Toll-like receptor genes is associated with low Toll-like receptor expression

    PubMed Central

    Zhong, Fei; Cao, Weiping; Chan, Edmund; Tay, Puei Nam; Cahya, Florence Feby; Zhang, Haifeng; Lu, Jinhua

    2005-01-01

    Microbial structures activate Toll-like receptors (TLRs) and TLR-mediated cell signalling elicits and regulates host immunity. Most TLRs are poorly expressed but the underlying expression mechanism is not clear. Examination TLR sequences revealed that most human TLR genes deviated from using major human codons. CD14 resembles TLRs in sequence but its gene preferentially uses major codons. Indeed, CD14 expression on monocytes was higher than expression of TLR1 and TLR2. The TLR9 gene is abundant in major codons and it also showed higher expression than TLR1, TLR2 and TLR7 in transfected 293T cells. Change of the 5′-end 302 base pairs of the TLR2 sequence into major human codons markedly increased TLR2 expression, which led to increased TLR2-mediated constitutive nuclear factor-κB activation. Change of the 5′-end 381 base pairs of the CD14 sequence into prevalent TLR codons markedly reduced CD14 expression. These results collectively show that the deviation of TLR sequences from using major codons dictates the low TLR expression and this may protect the host against excessive inflammation and tissue damages. PMID:15606798

  11. Toll like receptor polymorphisms in allogeneic hematopoietic cell transplantation

    PubMed Central

    Kornblit, Brian; Enevold, Christian; Wang, Tao; Spellman, Stephen; Haagenson, Mike; Lee, Stephanie J; Müller, Klaus

    2014-01-01

    To assess the impact of the genetic variation in toll-like receptors (TLR) on outcome after allogeneic myeloablative conditioning hematopoietic cell transplantation (HCT) we have investigated 29 single nucleotide polymorphisms (SNP) across 10 TLRs in 816 patients and donors. Only donor genotype of TLR8 rs3764879, which is located on the X chromosome, was significantly associated with outcome at the Bonferroni corrected level P≤0.001. Male hemizygosity and female homozygosity for the minor allele were significantly associated with disease free survival (DFS) (hazard ratio (HR) 1.47 (95% confidence interval (CI) 1.16–1.85); P=0.001). Further analysis stratified by donor sex due to confounding by sex, was suggestive for associations with overall survival (male donor: HR 1.41 (95% CI 1.09–1.83), P=0.010); female donor: (HR 2.78 (95% CI 1.43–5.41), P=0.003), DFS (male donor: HR 1.45 (95% CI 1.12–1.87), P=0.005; female donor: HR 2.34 (95% CI 1.18–4.65), P=0.015) and treatment related mortality (male donor: HR 1.49 (95% CI 1.09–2.04), P=0.012; female donor: HR 3.12 (95% CI 1.44–6.74), P=0.004). In conclusion our findings suggest that the minor allele of TLR8 rs3764879 of the donor is associated with outcome after myeloablative conditioned allogeneic HCT. PMID:25464115

  12. Toll-like receptor polymorphisms in allogeneic hematopoietic cell transplantation.

    PubMed

    Kornblit, Brian; Enevold, Christian; Wang, Tao; Spellman, Stephen; Haagenson, Mike; Lee, Stephanie J; Müller, Klaus

    2015-02-01

    To assess the impact of the genetic variation in toll-like receptors (TLRs) on outcome after allogeneic myeloablative conditioning hematopoietic cell transplantation (HCT), we investigated 29 single nucleotide polymorphisms across 10 TLRs in 816 patients and donors. Only donor genotype of TLR8 rs3764879, which is located on the X chromosome, was significantly associated with outcome at the Bonferroni-corrected level P ≤ .001. Male hemizygosity and female homozygosity for the minor allele were significantly associated with disease-free survival (hazard ratio [HR], 1.47 [95% confidence interval {CI}, 1.16 to 1.85]; P = .001). Further analysis stratified by donor sex due to confounding by sex was suggestive for associations with overall survival (male donor: HR, 1.41 [95% CI, 1.09 to 1.83], P = .010; female donor: HR, 2.78 [95% CI, 1.43 to 5.41], P = .003), disease-free survival (male donor: HR, 1.45 [95% CI, 1.12 to 1.87], P = .005; female donor: HR, 2.34 [95% CI, 1.18 to 4.65], P = .015), and treatment-related mortality (male donor: HR, 1.49 [95% CI, 1.09 to 2.04], P = .012; female donor: HR, 3.12 [95% CI, 1.44 to 6.74], P = .004). In conclusion, our findings suggest that the minor allele of TLR8 rs3764879 of the donor is associated with outcome after myeloablative conditioned allogeneic HCT. PMID:25464115

  13. Toll-like Receptors of the Ascidian Ciona intestinalis

    PubMed Central

    Sasaki, Naoko; Ogasawara, Michio; Sekiguchi, Toshio; Kusumoto, Shoichi; Satake, Honoo

    2009-01-01

    Key transmembrane proteins in the innate immune system, Toll-like receptors (TLRs), have been suggested to occur in the genome of non-mammalian organisms including invertebrates. However, authentic invertebrate TLRs have been neither structurally nor functionally investigated. In this paper, we originally present the structures, localization, ligand recognition, activities, and inflammatory cytokine production of all TLRs of the ascidian Ciona intestinalis, designated as Ci-TLR1 and Ci-TLR2. The amino acid sequence of Ci-TLR1 and Ci-TLR2 were found to possess unique structural organization with moderate sequence similarity to functionally characterized vertebrate TLRs. ci-tlr1 and ci-tlr2 genes were expressed predominantly in the stomach and intestine as well as in hemocytes. Ci-TLR1 and Ci-TLR2 expressed in HEK293 cells, unlike vertebrate TLRs, were localized to both the plasma membrane and endosomes. Intriguingly, both Ci-TLR1 and Ci-TLR2 stimulate NF-κB induction in response to multiple pathogenic ligands such as double-stranded RNA, and bacterial cell wall components that are differentially recognized by respective vertebrate TLRs, revealing that Ci-TLRs recognize broader pathogen-associated molecular patterns than vertebrate TLRs. The Ci-TLR-stimulating pathogenic ligands also induced the expression of Ci-TNFα in the intestine and stomach where Ci-TLRs are expressed. These results provide evidence that the TLR-triggered innate immune systems are essentially conserved in ascidians, and that Ci-TLRs possess “hybrid” biological and immunological functions, compared with vertebrate TLRs. Moreover, it is presumed that chordate TLR ancestors also acquired the Ci-TLR-like multiple cellular localization and pathogen-associated molecular pattern recognition. PMID:19651780

  14. Expression of antimicrobial peptides and toll-like receptors is increased in tinea and pityriasis versicolor.

    PubMed

    Brasch, J; Mörig, A; Neumann, B; Proksch, E

    2014-03-01

    In superficial tinea and pityriasis versicolor, the causative fungi are for the most part confined to the stratum corneum which is barely reached by leukocytes. Therefore, a role of non-cellular components in the epidermal antifungal defence was suggested. To investigate the presence of such factors in these infections, the expression of human beta defensins 2 and 3 (hBD-2, hBD-3), RNase 7, psoriasin, toll-like receptors 2, 4 and 9 (TLR2, TLR4 and TLR9) and dectin 2 was analysed by use of immunostainings in skin biopsies. We found that hBD2, hBD3, psoriasin, RNase7, TLR2 and TLR4 were significantly more often expressed in distinct layers of lesional epidermis as compared with uninfected epidermis. In both infections but not in normal skin, hBD2 and hBD3 were commonly expressed within the stratum corneum and in the stratum granulosum. Similarly, psoriasin was seen more often in the upper skin layers of both infections as compared with normal skin. No significant differences between normal and infected skin were found for the expression of TLR9 and dectin 2. Our findings clearly show the expression of specific antimicrobial proteins and defence-related ligands in superficial tinea as well as in pityriasis versicolor, suggesting that these factors contribute to fungal containment.

  15. A Role for the Adaptor Proteins TRAM and TRIF in Toll-like Receptor 2 Signaling*

    PubMed Central

    Nilsen, Nadra J.; Vladimer, Gregory I.; Stenvik, Jørgen; Orning, M. Pontus A.; Zeid-Kilani, Maria V.; Bugge, Marit; Bergstroem, Bjarte; Conlon, Joseph; Husebye, Harald; Hise, Amy G.; Fitzgerald, Katherine A.; Espevik, Terje; Lien, Egil

    2015-01-01

    Toll-like receptors (TLRs) are involved in sensing invading microbes by host innate immunity. TLR2 recognizes bacterial lipoproteins/lipopeptides, and lipopolysaccharide activates TLR4. TLR2 and TLR4 signal via the Toll/interleukin-1 receptor adaptors MyD88 and MAL, leading to NF-κB activation. TLR4 also utilizes the adaptors TRAM and TRIF, resulting in activation of interferon regulatory factor (IRF) 3. Here, we report a new role for TRAM and TRIF in TLR2 regulation and signaling. Interestingly, we observed that TLR2-mediated induction of the chemokine Ccl5 was impaired in TRAM or TRIF deficient macrophages. Inhibition of endocytosis reduced Ccl5 release, and the data also suggested that TRAM and TLR2 co-localize in early endosomes, supporting the hypothesis that signaling may occur from an intracellular compartment. Ccl5 release following lipoprotein challenge additionally involved the kinase Tbk-1 and Irf3, as well as MyD88 and Irf1. Induction of Interferon-β and Ccl4 by lipoproteins was also partially impaired in cells lacking TRIF cells. Our results show a novel function of TRAM and TRIF in TLR2-mediated signal transduction, and the findings broaden our understanding of how Toll/interleukin-1 receptor adaptor proteins may participate in signaling downstream from TLR2. PMID:25505250

  16. [Congenital components of immunity: Toll-like receptors in the normal state and in immunopathology].

    PubMed

    Koval'chuk, L V; Khoreva, M V; Varivoda, A S

    2005-01-01

    This review deals with rapidly accumulating information on a highly important components of the congenital immune system: Toll-like receptors playing a leading role in the recognition of microbial patterns. The data on the main structural and functional features of Toll-like receptors and their distribution in the body are summarized. The main signal paths are characterized and the key molecules which take part in the transduction are pointed out. Special attention is paid to the activating action of lipopolysaccharides through TLR4. Pathological processes developing as the result of damages in the structure and function of Toll-like receptors in humans and experimental animals are determined.

  17. Characterization, expression analysis and localization pattern of toll-like receptor 1 (tlr1) and toll-like receptor 2 (tlr2) genes in grass carp Ctenopharyngodon idella.

    PubMed

    He, L B; Wang, H; Luo, L F; Jiang, S H; Liu, L Y; Li, Y M; Huang, R; Liao, L J; Zhu, Z Y; Wang, Y P

    2016-08-01

    In this study, the toll-like receptor 1 (tlr1) and toll-like receptor 2 (tlr2) genes of grass carp Ctenopharyngodon idella were cloned and characterized. tlr1 and tlr2 were found to be highly expressed in immune system organs such as spleen, middle kidney and heart kidney. The expression level of tlr1 and tlr2 was found to be up-regulated at the later stage of viral challenge process. Moreover, subcellular localization indicated that Tlr1 and Tlr2 shared similar localization pattern and both of them may locate in the plasma membrane of transfected cells. PMID:27221024

  18. 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

  19. Toll-like receptor-deficient mice reveal how innate immune signaling influences Salmonella virulence strategies.

    PubMed

    Sivick, Kelsey E; Arpaia, Nicholas; Reiner, Gabrielle L; Lee, Bettina L; Russell, Bethany R; Barton, Gregory M

    2014-02-12

    Pathogens utilize features of the host response as cues to regulate virulence gene expression. Salmonella enterica serovar Typhimurium (ST) sense Toll-like receptor (TLR)-dependent signals to induce Salmonella Pathogenicity Island 2 (SPI2), a locus required for intracellular replication. To examine pathogenicity in the absence of such cues, we evaluated ST virulence in mice lacking all TLR function (Tlr2(-/-)xTlr4(-/-)xUnc93b1(3d/3d)). When delivered systemically to TLR-deficient mice, ST do not require SPI2 and maintain virulence by replicating extracellularly. In contrast, SPI2 mutant ST are highly attenuated after oral infection of the same mice, revealing a role for SPI2 in the earliest stages of infection, even when intracellular replication is not required. This early requirement for SPI2 is abolished in MyD88(-/-)xTRIF(-/-) mice lacking both TLR- and other MyD88-dependent signaling pathways, a potential consequence of compromised intestinal permeability. These results demonstrate how pathogens use plasticity in virulence strategies to respond to different host immune environments.

  20. Hypoxia attenuates inflammatory mediators production induced by Acanthamoeba via Toll-like receptor 4 signaling in human corneal epithelial cells

    SciTech Connect

    Pan, Hong; Wu, Xinyi

    2012-04-13

    Highlights: Black-Right-Pointing-Pointer Hypoxia attenuates Acanthamoeba-induced the production of IL-8 and IFN-{beta}. Black-Right-Pointing-Pointer Hypoxia inhibits TLR4 expression in a time-dependent manner in HCECs. Black-Right-Pointing-Pointer Hypoxia inhibits Acanthamoeba-induced the activation of NF-{kappa}B and ERK1/2 in HCECs. Black-Right-Pointing-Pointer Hypoxia decreases Acanthamoeba-induced inflammatory response via TLR4 signaling. Black-Right-Pointing-Pointer LPS-induced the secretion of IL-6 and IL-8 is abated by hypoxia via TLR4 signaling. -- Abstract: Acanthamoeba keratitis (AK) is a vision-threatening corneal infection that is intimately associated with contact lens use which leads to hypoxic conditions on the corneal surface. However, the effect of hypoxia on the Acanthamoeba-induced host inflammatory response of corneal epithelial cells has not been studied. In the present study, we investigated the effect of hypoxia on the Acanthamoeba-induced production of inflammatory mediators interleukin-8 (IL-8) and interferon-{beta} (IFN-{beta}) in human corneal epithelial cells and then evaluated its effects on the Toll-like receptor 4 (TLR4) signaling, including TLR4 and myeloid differentiation primary response gene (88) (MyD88) expression as well as the activation of nuclear factor kappa-light-chain-enhancer of activated B cells (NF-{kappa}B) and extracellular signal-regulated kinases 1/2 (ERK1/2). We then studied the effect of hypoxia on a TLR4-specific inflammatory response triggered by the TLR4 ligand lipopolysaccharide (LPS). Our data showed that hypoxia significantly decreased the production of IL-8 and IFN-{beta}. Furthermore, hypoxia attenuated Acanthamoeba-triggered TLR4 expression as well as the activation of NF-{kappa}B and ERK1/2, indicating that hypoxia abated Acanthamoeba-induced inflammatory responses by affecting TLR4 signaling. Hypoxia also inhibited LPS-induced IL-6 and IL-8 secretion, myeloid differentiation primary response gene (88

  1. 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

  2. Reduced cerebral ischemia-reperfusion injury in Toll-like receptor 4 deficient mice

    SciTech Connect

    Cao Canxiang; Yang Qingwu . E-mail: yangqwmlys@hotmail.com; Lv Fenglin; Cui Jie; Fu Huabin; Wang Jingzhou

    2007-02-09

    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} and 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.

  3. The Molecular Chaperone GRP78 Contributes to Toll-like Receptor 3-mediated Innate Immune Response to Hepatitis C Virus in Hepatocytes.

    PubMed

    Wei, Dahai; Li, Nan L; Zeng, Yanli; Liu, Baoming; Kumthip, Kattareeya; Wang, Tony T; Huo, Dezheng; Ingels, Jesse F; Lu, Lu; Shang, Jia; Li, Kui

    2016-06-01

    Toll-like receptor-3 (TLR3) senses double-stranded RNA intermediates produced during hepatitis C virus (HCV) replication, leading to activation of interferon regulatory factor-3 (IRF3) and NF-κB and subsequent antiviral and proinflammatory responses. Yet, how this TLR3-dependent pathway operates in hepatocytes is unclear. Upon fractionating cultured hepatocytes into various cellular organelles, we observed that TLR3 predominantly resides in endolysosomes of hepatocytes. To determine the critical regulators of TLR3 signaling in response to HCV infection in human hepatocytes, we isolated endolysosome fractions from mock-infected and HCV-infected hepatoma Huh7.5 cells that had been reconstituted for TLR3 expression, separated these fractions on two-dimensional gels, and identified up-regulated/down-regulated proteins by mass spectrometry. Approximately a dozen of cellular proteins were found to be differentially expressed in endolysosome fractions following HCV infection. Of these, expression of several molecular chaperone proteins was elevated. Knockdown of one of these chaperones, glucose-regulated protein 78 kDa (GRP78), compromised TLR3-dependent induction of interferon-stimulated genes and chemokines following HCV infection or poly(I:C) stimulation in cultured hepatocytes. Consistent with this finding, GRP78 depletion impaired TLR3-mediated establishment of an antiviral state. Mechanistically, although TLR3 trafficking to endolysosomes was not affected, phosphorylated IRF3 diminished faster following GRP78 knockdown. Remarkably, GRP78 transcript was significantly up-regulated in liver biopsies of chronic hepatitis C patients as compared with normal liver tissues. Moreover, the GRP78 expression level correlated with that of RANTES (regulated upon activation, normal T-cell expressed and secreted) and CXCL10, two inflammatory chemokines most frequently elevated in HCV-infected liver. Altogether, our data suggest that GRP78 contributes to TLR3-mediated, IRF3

  4. Anaerobic Infections in Children with Neurological Impairments.

    ERIC Educational Resources Information Center

    Brook, Itzhak

    1995-01-01

    Children with neurological impairments are prone to develop serious infection with anaerobic bacteria. The most common anaerobic infections are decubitus ulcers; gastrostomy site wound infections; pulmonary infections (aspiration pneumonia, lung abscesses, and tracheitis); and chronic suppurative otitis media. The unique microbiology of each of…

  5. 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

    2016-01-01

    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.

  6. 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

  7. Toll-Like Receptors in Liver Fibrosis: Cellular Crosstalk and Mechanisms

    PubMed Central

    Yang, Ling; Seki, Ekihiro

    2012-01-01

    Toll-like receptors (TLRs) are pattern recognition receptors that distinguish conserved microbial products, also known as pathogen-associated molecular patterns (PAMPs), from host molecules. Liver is the first filter organ between the gastrointestinal tracts and the rest of the body through portal circulation. Thus, the liver is a major organ that must deal with PAMPs and microorganisms translocated from the intestine and to respond to the damage associated molecular patterns (DAMPs) released from injured organs. These PAMPs and DAMPs preferentially activate TLR signaling on various cell types in the liver inducing the production of inflammatory and fibrogenic cytokines that initiate and prolong liver inflammation, thereby leading to fibrosis. We summarize recent findings on the role of TLRs, ligands, and intracellular signaling in the pathophysiology of liver fibrosis due to different etiology, as well as to highlight the potential role of TLR signaling in liver fibrosis associated with hepatitis C infection, non-alcoholic and alcoholic steatoheoatitis, primary biliary cirrhosis, and cystic fibrosis. PMID:22661952

  8. 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.

  9. Reduced bioenergetics and toll-like receptor 1 function in human polymorphonuclear leukocytes in aging.

    PubMed

    Qian, Feng; Guo, Xiuyang; Wang, Xiaomei; Yuan, Xiaoling; Chen, Shu; Malawista, Stephen E; Bockenstedt, Linda K; Allore, Heather G; Montgomery, Ruth R

    2014-02-01

    Aging is associated with a progressive decline in immune function (immunosenescence) resulting in an increased susceptibility to viral and bacterial infections. Here we show reduced expression of Toll-like receptor 1 (TLR1) in polymorphonuclear leukocytes (PMN) and an underlying age-dependent deficiency in PMN bioenergetics. In older (>65 years) adults, stimulation through TLR1 led to lower activation of integrins (CD11b and CD18), lower production of the chemokine IL-8, and lower levels of the phosphorylated signaling intermediate p38 MAP kinase than in PMN from younger donors (21-30 years). In addition, loss of CD62L, a marker of PMN activation, was reduced in PMN of older adults stimulated through multiple pathways. Rescue of PMN from apoptosis by stimulation with TLR1 was reduced in PMN from older adults. In seeking an explanation for effects of aging across multiple pathways, we examined PMN energy utilization and found that glucose uptake after stimulation through TLR1 was dramatically lower in PMN of older adults. Our results demonstrate a reduction in TLR1 expression and TLR1-mediated responses in PMN with aging, and reduced efficiency of bioenergetics in PMN. These changes likely contribute to reduced PMN efficiency in aging through multiple aspects of PMN function and suggest potential therapeutic opportunities.

  10. 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

    2015-01-01

    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

  11. Endosomal Toll-like receptors in clinically overt and silent autoimmunity.

    PubMed

    Clancy, Robert M; Markham, Androo J; Buyon, Jill P

    2016-01-01

    Toll-like receptors (TLRs), first identified as pattern recognition receptors, are now recognized to serve as a key interface between innate and adaptive immunity. Systemic lupus erythematosus (SLE) is characterized by both continuous and cyclic stimulation of the innate and adaptive immune system by endogenous nucleic acids released from apoptotic or necrotic cells. TLR7 and TLR9 function as innate sensors of viral infection as their ligands are ssRNA and dsDNA, respectively. Recognition of self nucleic acids by endosomal TLRs in B cells and pDCs is thought to be an important step in the pathogenesis of SLE, generating anti-nuclear antibodies and producing type I IFN. In this review, we take a specific look at how TLR7, non-coding RNA, and SSA/Ro60 can contribute to clinical autoimmunity and organ damage in the context of neonatal lupus (NL). Although 15 times less common than SLE, NL provides a unique opportunity to study two different aspects of autoimmunity: passively acquired tissue injury in a developing fetus and clinical progression of disease in an asymptomatic mother found to have anti-Ro60 autoantibodies only after identification of heart block/rash in a child. Finally, we discuss hydroxychloroquine (HCQ) use by asymptomatic subjects which may forestall the clinical expression of autoimmunity.

  12. 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.

  13. Toll-like receptor 2 activation depends on lipopeptide shedding by bacterial surfactants

    PubMed Central

    Hanzelmann, Dennis; Joo, Hwang-Soo; Franz-Wachtel, Mirita; Hertlein, Tobias; Stevanovic, Stefan; Macek, Boris; Wolz, Christiane; Götz, Friedrich; Otto, Michael; Kretschmer, Dorothee; Peschel, Andreas

    2016-01-01

    Sepsis caused by Gram-positive bacterial pathogens is a major fatal disease but its molecular basis remains elusive. Toll-like receptor 2 (TLR2) has been implicated in the orchestration of inflammation and sepsis but its role appears to vary for different pathogen species and clones. Accordingly, Staphylococcus aureus clinical isolates differ substantially in their capacity to activate TLR2. Here we show that strong TLR2 stimulation depends on high-level production of phenol-soluble modulin (PSM) peptides in response to the global virulence activator Agr. PSMs are required for mobilizing lipoproteins, the TLR2 agonists, from the staphylococcal cytoplasmic membrane. Notably, the course of sepsis caused by PSM-deficient S. aureus is similar in wild-type and TLR2-deficient mice, but TLR2 is required for protection of mice against PSM-producing S. aureus. Thus, a crucial role of TLR2 depends on agonist release by bacterial surfactants. Modulation of this process may lead to new therapeutic strategies against Gram-positive infections. PMID:27470911

  14. Toll-like Receptor 4 (TLR4) modulation by synthetic and natural compounds: an update

    PubMed Central

    Peri, Francesco; Calabrese, Valentina

    2014-01-01

    Toll-like receptor 4 (TLR4), together with MD-2, binds bacterial endotoxins (E) with high affinity, triggering formation of the activated homodimer (E-MD-2-TLR4)2. Activated TLR4 induces intracellular signaling leading to activation of transcription factors that result in cytokine and chemokine production and initiation of inflammatory and immune responses. TLR4 also responds to endogenous ligands called danger associated molecular patterns (DAMPs). Increased sensitivity to infection and a variety of immune pathologies have been associated with either too little or too much TLR4 activation. We review here the molecular mechanisms of TLR4 activation (agonism) or inhibition (antagonism) by small organic molecules of both natural and synthetic origin. The role of co-receptors MD-2 and CD14 in the TLR4 modulation process is also discussed. Recent achievements in the field of chemical TLR4 modulation are reviewed, with special focus on non-classical TLR4 ligands with a chemical structure different from lipid A. PMID:24188011

  15. Chemotherapy-induced mucositis: the role of the gastrointestinal microbiome and toll-like receptors.

    PubMed

    Thorpe, Daniel W; Stringer, Andrea M; Gibson, Rachel J

    2013-01-01

    Alimentary mucositis is a major clinical problem. Patients with mucositis are at significantly increased risk of infection and are often hospitalized for prolonged periods. More importantly, these patients often have to undergo reductions in their cytotoxic therapy, which may lead to reduced survival. Unfortunately, there are very limited therapeutic options for mucositis and no effective prevention. The human gut microbiome is receiving increased attention as a key player in the pathogenesis of alimentary mucositis with recent literature suggesting that changes in bacteria lead to mucositis. The bacteria which are found throughout the gut are tightly regulated by the toll-like receptor (TLR) family which currently has 13 known members. TLRs play a critical role in gut homeostasis and bacterial regulation. Furthermore, TLRs play a critical role in the regulation of nuclear factor kappa B, a key regulator of alimentary mucositis. However to date, no research has clearly identified a link between TLRs and alimentary mucositis. This critical literature review seeks to correct this.

  16. Toll-like receptors: the swiss army knife of immunity and vaccine development

    PubMed Central

    Dowling, Jennifer K; Mansell, Ashley

    2016-01-01

    Innate immune cells have a critical role in defense against infection and disease. Central to this is the broad specificity with which they can detect pathogen-associated patterns and danger-associated patterns via the pattern recognition receptors (PRRs) they express. Several families of PRRs have been identified including: Toll-like receptors (TLRs), C-type lectin-like receptors, retinoic acid-inducible gene-like receptors and nucleotide-binding oligomerization domain–like receptors. TLRs are one of the most largely studied families of PRRs. The binding of ligands to TLRs on antigen presenting cells (APCs), mainly dendritic cells, leads to APC maturation, induction of inflammatory cytokines and the priming of naive T cells to drive acquired immunity. Therefore, activation of TLRs promotes both innate inflammatory responses and the induction of adaptive immunity. Consequently, in the last two decades mounting evidence has inextricably linked TLR activation with the pathogenesis of immune diseases and cancer. It has become advantageous to harness these aspects of TLR signaling therapeutically to accelerate and enhance the induction of vaccine-specific responses and also target TLRs with the use of biologics and small molecule inhibitors for the treatment of disease. In these respects, TLRs may be considered a ‘Swiss Army' knife of the immune system, ready to respond in a multitude of infectious and disease states. Here we describe the latest advances in TLR-targeted therapeutics and the use of TLR ligands as vaccine adjuvants. PMID:27350884

  17. RANTES expression induced by Toll-like receptor 4 ligand in rat airway smooth muscle cells.

    PubMed

    Okayasu, Kaori; Tamaoka, Meiyo; Takayama, Satoshi; Miyazaki, Yasunari; Sumi, Yuki; Inase, Naohiko; Yoshizawa, Yasuyuki

    2010-01-01

    Airway smooth muscle cells (ASMCs) have been reported to express Toll-like receptors (TLRs) and take part in the pathogenesis of asthma exacerbation. Though TLRs were found to activate epidermal growth factor receptor (EGFR) in airway epithelial cells, little is known about the association of TLR ligands with EGFR signaling pathways in ASMCs. Using primary cultured ASMCs from Brown Norway rats, TLR4, eotaxin, and RANTES mRNA were examined by real-time quantitative RT-PCR after stimulation with the TLR4 ligand, lipopolysaccharides (LPS). The concentration of RANTES protein in culture supernatant was measured by ELISA. The effect of EGFR signaling inhibitors on RANTES expression was examined as well. Phosphorylation of EGFR after stimulation was examined by Western Blotting. Rat ASMCs expressed TLR4 and eotaxin, and LPS upregulated RANTES production. The EGFR tyrosine kinase inhibitor AG1478, the phosphoinositide 3-kinase (PI3K) inhibitor LY294002, and the matrix metalloproteinase (MMP) inhibitor GM6001 inhibited RANTES expression induced by LPS. LPS phosphorylated EGFR. TLR4 activation can induce RANTES expression via EGFR transactivation and PI3K/Akt pathway in rat ASMCs. MMP-induced EGFR proligand cleavage and ligand binding to EGFR seem to be involved in this pathway. These findings may be critical in the pathogenesis of asthma exacerbation by airway infection. PMID:23896774

  18. 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.

  19. 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

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

    PubMed Central

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

    2014-01-01

    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. PMID:25118589

  1. Activation of epidermal toll-like receptor 2 enhances tight junction function – Implications for atopic dermatitis and skin barrier repair

    PubMed Central

    Kuo, I-Hsin; Carpenter-Mendini, Amanda; Yoshida, Takeshi; McGirt, Laura Y.; Ivanov, Andrei I.; Barnes, Kathleen C.; Gallo, Richard L.; Borkowski, Andrew W.; Yamasaki, Kenshi; Leung, Donald Y.; Georas, Steve N.; De Benedetto, Anna; Beck, Lisa A.

    2012-01-01

    Atopic dermatitis (AD) is characterized by epidermal tight junction (TJ) defects and a propensity for Staphylococcus aureus (S. aureus) skin infections. S. aureus is sensed by many pattern recognition receptors including toll-like receptor (TLR) 2. We hypothesized that an effective innate immune response will include skin barrier repair and that this response is impaired in AD subjects. S. aureus-derived peptidoglycan (PGN) and synthetic TLR2 agonists enhanced TJ barrier and increased expression of TJ proteins, CLDN1, CLDN23, occludin and ZO-1 in primary human keratinocytes. A TLR2 agonist enhanced skin barrier recovery in human epidermis wounded by tape-stripping. Tlr2−/− mice had a delayed and incomplete barrier recovery following tape-stripping. AD subjects had reduced epidermal TLR2 expression as compared to nonatopic (NA) subjects, which inversely correlated (r= 0.654, P= 0.0004) with transepidermal water loss (TEWL). These observations indicate that TLR2 activation enhances skin barrier in murine and human skin and is an important part of a wound repair response. Reduced epidermal TLR2 expression observed in AD patients may play a role in their incompetent skin barrier. PMID:23223142

  2. Effects of P-MAPA immunomodulator on Toll-like receptor 2, ROS, nitric oxide, MAPKp38 and IKK in PBMC and macrophages from dogs with visceral leishmaniasis.

    PubMed

    Melo, L M; Perosso, J; Almeida, B F M; Silva, K L O; Somenzari, M A; de Lima, V M F

    2014-02-01

    Leishmania (L.) chagasi is the etiologic agent of visceral leishmaniasis (VL) that can be transmitted to humans and dogs. VL in Brazil represents a serious public health problem; therefore, it is important to study new alternatives to treat infected dogs. In dogs, the therapeutic arsenal against canine VL is limited. The immunomodulator protein aggregate magnesium-ammonium phospholinoleate-palmitoleate anhydride (P-MAPA) improves immunocompetence when the immune system is impaired, but its dependence on Toll-like receptors (TLRs) and the mechanisms involved in immune response remain unclear. The in vitro action of P-MAPA on the expression of TLR2 and TLR4, reactive oxygen species (ROS), nitric oxide (NO) and p38 mitogen-activated protein kinase (p38 MAPK) and IKK phosphorylation was studied in mononuclear cells from peripheral blood and macrophages from healthy and Leishmania-infected dogs. The PBMC or macrophages were isolated and cultured with different concentrations of P-MAPA (20,100 and 200 μg/ml) in a humid environment at 37°C with 5% CO(2). Observation revealed that Leishmania-infected dogs showed a decrease in TLR2 in macrophages compared with healthy dogs and in induction with P-MAPA. ROS were increased in PBMCs from Leishmania spp.-infected dogs compared with healthy dogs and P-MAPA improved ROS production. NO production was increased in culture supernatant from macrophages stimulated by P-MAPA in both healthy and Leishmania spp. infected dogs. Treatment of macrophages from healthy dogs with immunomodulatory P-MAPA induced p38 MAPK and IKK phosphorylation, suggesting signal transduction by this pathway. These findings suggest that P-MAPA has potential as a therapeutic drug in the treatment of canine visceral leishmaniasis.

  3. 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

  4. A Coding IRAK2 Protein Variant Compromises Toll-like receptor (TLR) Signaling and Is Associated with Colorectal Cancer Survival*

    PubMed Central

    Wang, Hui; Flannery, Sinead M.; Dickhöfer, Sabine; Huhn, Stefanie; George, Julie; Kubarenko, Andriy V.; Lascorz, Jesus; Bevier, Melanie; Willemsen, Joschka; Pichulik, Tica; Schafmayer, Clemens; Binder, Marco; Manoury, Bénédicte; Paludan, Søren R.; Alarcon-Riquelme, Marta; Bowie, Andrew G.; Försti, Asta; Weber, Alexander N. R.

    2014-01-01

    Within innate immune signaling pathways, interleukin-1 receptor-associated kinases (IRAKs) fulfill key roles downstream of multiple Toll-like receptors and the interleukin-1 receptor. Although human IRAK4 deficiency was shown to lead to severe immunodeficiency in response to pyogenic bacterial infection during childhood, little is known about the role of human IRAK2. We here identified a non-synonymous IRAK2 variant, rs35060588 (coding R214G), as hypofunctional in terms of NF-κB signaling and Toll-like receptor-mediated cytokine induction. This was due to reduced ubiquitination of TRAF6, a key step in signal transduction. IRAK2 rs35060588 occurs in 3–9% of individuals in different ethnic groups, and our studies suggested a genetic association of rs35060588 with colorectal cancer survival. This for the first time implicates human IRAK2 in a human disease and highlights the R214G IRAK2 variant as a potential novel and broadly applicable biomarker for disease or as a therapeutic intervention point. PMID:24973222

  5. 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.

  6. Insights into Soluble Toll-Like Receptor 2 as a Downregulator of Virally Induced Inflammation

    PubMed Central

    Henrick, Bethany M.; Yao, Xiao-Dan; Taha, Ameer Y.; German, J. Bruce; Rosenthal, Kenneth Lee

    2016-01-01

    The ability to distinguish pathogens from self-antigens is one of the most important functions of the immune system. However, this simple self versus non-self assignment belies the complexity of the immune response to threats. Immune responses vary widely and appropriately according to a spectrum of threats and only recently have the mechanisms for controlling this highly textured process emerged. A primary mechanism by which this controlled decision-making process is achieved is via Toll-like receptor (TLR) signaling and the subsequent activation of the immune response coincident with the presence of pathogenic organisms or antigens, including lipid mediators. While immune activation is important, the appropriate regulation of such responses is also critical. Recent findings indicate a parallel pathway by which responses to both viral and bacterial infections is controlled via the secretion of soluble TLR2 (sTLR2). sTLR2 is able to bind a wide range of pathogen-associated molecular patterns (PAMPs) and danger-associated molecular patterns (DAMPs). sTLR2 has been detected in many bodily fluids and is thus ubiquitous in sites of pathogen appearance. Interestingly, growing evidence suggests that sTLR2 functions to sequester PAMPs and DAMPs to avoid immune activation via detection of cellular-expressed TLRs. This immune regulatory function would serve to reduce the expression of the molecules required for cellular entry, and the recruitment of target cells following infection with bacteria and viruses. This review provides an overview of sTLR2 and the research regarding the mechanisms of its immune regulatory properties. Furthermore, the role of this molecule in regulating immune activation in the context of HIV infection via sTLR2 in breast milk provides actionable insights into therapeutic targets across a variety of infectious and inflammatory states. PMID:27531999

  7. Role of Toll-Like Receptor 13 in Innate Immune Recognition of Group B Streptococci

    PubMed Central

    Signorino, Giacomo; Mohammadi, Nastaran; Patanè, Francesco; Buscetta, Marco; Venza, Mario; Venza, Isabella; Mancuso, Giuseppe; Midiri, Angelina; Alexopoulou, Lena; Teti, Giuseppe; Beninati, Concetta

    2014-01-01

    Murine Toll-like receptor 13 (TLR13), an endosomal receptor that is not present in humans, is activated by an unmethylated motif present in the large ribosomal subunit of bacterial RNA (23S rRNA). Little is known, however, of the impact of TLR13 on antibacterial host defenses. Here we examined the role of this receptor in the context of infection induced by the model pathogen group B streptococcus (GBS). To this end, we used bacterial strains masked from TLR13 recognition by virtue of constitutive expression of the ErmC methyltransferase, which results in dimethylation of the 23S rRNA motif at a critical adenine residue. We found that TLR13-mediated rRNA recognition was required for optimal induction of tumor necrosis factor alpha and nitrous oxide in dendritic cell and macrophage cultures stimulated with heat-killed bacteria or purified bacterial RNA. However, TLR13-dependent recognition was redundant when live bacteria were used as a stimulus. Moreover, masking bacterial rRNA from TLR13 recognition did not increase the ability of GBS to avoid host defenses and replicate in vivo. In contrast, increased susceptibility to infection was observed under conditions in which signaling by all endosomal TLRs was abolished, i.e., in mice with a loss-of-function mutation in the chaperone protein UNC93B1. Our data lend support to the conclusion that TLR13 participates in GBS recognition, although blockade of the function of this receptor can be compensated for by other endosomal TLRs. Lack of selective pressure by bacterial infections might explain the evolutionary loss of TLR13 in humans. However, further studies using different bacterial species are needed to prove this hypothesis. PMID:25225249

  8. Expression and functionality of Toll-like receptor 3 in the megakaryocytic lineage

    PubMed Central

    D’Atri, L. P.; Etulain, J.; Rivadeneyra, L.; Lapponi, M. J.; Centurion, M.; Cheng, K.; Yin, H.; Schattner, M.

    2015-01-01

    Summary Background In addition to their key role in hemostasis, platelets and megakaryocytes also regulate immune and inflammatory responses, in part through their expression of Toll-like receptors (TLRs). Among the TLRs, TLR3 recognizes double-stranded (ds) RNA associated with viral infection. Thrombocytopenia is a frequent complication of viral infection. However, the expression and functionality of TLR3 in megakaryocytes and platelets is not yet well understood. Objective To study the expression and functionality of TLR3 in the megakaryocytic lineage. Methods and Results RT-PCR, flow cytometric, and immunofluorescence assays showed that TLR3 is expressed in CD34+ cells, megakaryocytes, and platelets. Immunoblotting assays showed that stimulation of megakaryocytes with two synthetic agonists of TLR3, Poly(I:C) and Poly(A:U), activated the NF-κB, PI3K/Akt, ERK1/2, and p38 pathways. TLR3-megakaryocyte activation resulted in reduced platelet production in vitro and IFN-β release through the PI3K/Akt and NF-κB signaling pathways. TLR3 ligands potentiated the aggregation mediated by classical platelet agonists. This effect was also observed for ATP release, but not for P-selectin or CD40L membrane exposure, indicating that TLR3 activation was not involved in alpha granule release. In addition, TLR3 agonists induced activation of the NF-κB, PI3K/Akt, and ERK1/2 pathways in platelets. Reduction of platelet production and platelet fibrinogen binding mediated by Poly(I:C) or Poly(A:U) were prevented by the presence of an inhibitor of TLR3/dsRNA complex. Conclusions Our findings indicate that functional TLR3 is expressed in CD34+ cells, megakaryocytes, and platelets, and suggest a potential role for this receptor in the megakaryo/thrombopoiesis alterations that occur in viral infections. PMID:25594115

  9. Reduction of avian influenza virus shedding by administration of Toll-like receptor ligands to chickens.

    PubMed

    Barjesteh, Neda; Shojadoost, Bahram; Brisbin, Jennifer T; Emam, Mehdi; Hodgins, Douglas C; Nagy, Éva; Sharif, Shayan

    2015-09-11

    Avian influenza viruses (AIV) are of concern to the poultry industry. Outbreaks of AIV highlight the urgent need for effective control measures. Prophylactic strategies should be explored that rapidly elicit immunity against the virus. Toll-like receptors (TLRs) are innate immune molecules that can induce anti-viral responses, therefore the application of TLR ligands as prophylactic agents in chickens is gaining more attention. We hypothesized that treatment of chickens with TLR ligands reduces the shedding of AIV from infected birds. In addition, the effects of TLR ligand dose and route of administration on the efficiency of TLR ligands to reduce AIV shedding were examined. Chickens were treated with TLR2, 4, 7 and 21 ligands using different doses and routes of administration, 18h before AIV infection. Moreover, the expression of several candidate genes, such as type I interferons, PKR, OAS, viperin and IFITM3 was quantified at 3, 8 and 18h post-treatment with TLR ligands. The results revealed that route of administration and dosage affect the efficacy of TLR ligands to reduce virus shedding. Furthermore, varying effects were observed when different ligands were applied. Our results demonstrated that all TLR ligand treatments reduced AIV shedding, with the CpG-ODN 1826 being the most efficacious to reduce oral virus shedding, whereas LPS from Escherichia coli 026:B6 resulted in the largest reduction in cloacal virus shedding. Moreover, TLR ligands induced the expression of genes involved in antiviral responses such as type I interferons and interferon-stimulated genes in chicken trachea and cecal tonsils. These results raise the possibility of treatment of chickens with TLR ligands as anti-viral agents.

  10. Role of Toll-Like Receptor Signaling in the Pathogenesis of Graft-versus-Host Diseases

    PubMed Central

    Tu, Sanfang; Zhong, Danli; Xie, Weixin; Huang, Wenfa; Jiang, Yangyang; Li, Yuhua

    2016-01-01

    Graft-versus-host disease (GVHD) and infection are major complications after allogeneic hematopoietic stem cell transplantation (allo-HSCT) and the leading causes of morbidity and mortality in HSCT patients. Recent work has demonstrated that the two complications are interdependent. GVHD occurs when allo-reactive donor T lymphocytes are activated by major histocompatibility antigens or minor histocompatibility antigens on host antigen-presenting cells (APCs), with the eventual attack of recipient tissues or organs. Activation of APCs is important for the priming of GVHD and is mediated by innate immune signaling pathways. Current evidence indicates that intestinal microbes and innate pattern-recognition receptors (PRRs) on host APCs, including both Toll-like receptors (TLRs) and nucleotide oligomerization domain (NOD)-like receptors (NLRs), are involved in the pathogenesis of GVHD. Patients undergoing chemotherapy and/or total body irradiation before allo-HSCT are susceptible to aggravated gastrointestinal epithelial cell damage and the subsequent translocation of bacterial components, followed by the release of endogenous dangerous molecules, termed pathogen-associated molecular patterns (PAMPs), which then activate the PRRs on host APCs to trigger local or systemic inflammatory responses that modulate T cell allo-reactivity against host tissues, which is equivalent to GVHD. In other words, infection can, to some extent, accelerate the progression of GVHD. Therefore, the intestinal flora’s PAMPs can interact with TLRs to activate and mature APCs, subsequently activate donor T cells with the release of pro-inflammatory cytokines, and eventually, induce GVHD. In the present article, we summarize the current perspectives on the understanding of different TLR signaling pathways and their involvement in the occurrence of GVHD. PMID:27529218

  11. Toll-like receptor-mediated signaling cascade as a regulator of the inflammation network during alcoholic liver disease

    PubMed Central

    Ceccarelli, Sara; Nobili, Valerio; Alisi, Anna

    2014-01-01

    Chronic abuse of alcohol leads to various histological abnormalities in the liver. These are conditions collectively known as alcoholic liver disease (ALD). Currently, ALD is considered to be one of the major causes of death worldwide. An impaired intestinal barrier with related endotoxemia is among the various pathogenetic factors. This is mainly characterized by circulating levels of lipopolysaccharide (LPS), considered critical for the onset of intra-hepatic inflammation. This in turn promotes hepatocellular damage and fibrosis in ALD. Elevated levels of LPS exert their effects by binding to Toll-like receptors (TLRs) which are expressed by all liver-resident cells. The activation of TLR signaling triggers an overproduction and release of some cytokines, which promote an autocatalytic cascade of other pro-inflammatory signals. In this review, we provide an overview of the mechanisms that sustain LPS-mediated activation of TLR signaling, reporting current experimental and clinical evidence of its role during inflammation in ALD. PMID:25469012

  12. 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

  13. Toll-like receptor-4-dependence of the lipopolysaccharide-mediated inhibition of osteoblast differentiation.

    PubMed

    Liu, Y H; Huang, D; Li, Z J; Li, X H; Wang, X; Yang, H P; Tian, S P; Mao, Y; Liu, M F; Wang, Y F; Wu6, Y; Han7, X F

    2016-01-01

    Bone fractures or bones subjected to open conduction and internal fixation are easily infected by bacteria; bacterial lipopolysaccharide (LPS) has been recognized as an important pathogenic factor affecting bone fracture healing. Therefore, the effect of LPS on bone metabolism is relevant for bone healing. In this study, we investigated the effect of LPS on the expression of Toll-like receptor (TLR)-4 (an LPS receptor) by using real-time quantitative PCR and western blotting. We also examined the regulatory role of LPS in osteoblast differentiation by measuring the ALP activity, matrix mineralization, and ALP, OCN, and Runx2 mRNA (essential factors affecting osteoblast differentiation) expression in LPS-treated mouse osteoblast MC3T3-E1 cells. We also evaluated the effect of TLR-4 on LPS-mediated inhibition of osteoblast differentiation using RNA interference. LPS promotes TLR-4 mRNA and protein expression in MC3T3-E1 cells (P < 0.05, P < 0.01 or P < 0.001), and inhibits osteoblast differentiation by downregulating matrix mineralization and ALP activity (P < 0.05, P < 0.01 or P < 0.001), and suppressing the expression ALP, OCN, and Runx2 mRNA in MC3T3-E1 cells (P < 0.05 or P < 0.01). Conversely, RNAi-mediated TLR-4 knockdown abrogates the LPS-mediated inhibition of osteoblast differentiation (P < 0.05 or P < 0.01). In summary, LPS was shown to inhibit osteoblast differentiation by suppressing the expression of ALP, OCN, and Runx2 in a TLR-4-dependent manner. The results of this study may provide insights into the signal pathway of LPS-induced bone loss or delayed bone fracture healing. PMID:27173231

  14. Oligosaccharides of Hyaluronan Activate Dendritic Cells via Toll-like Receptor 4

    PubMed Central

    Termeer, Christian; Benedix, Frauke; Sleeman, Jonathon; Fieber, Christina; Voith, Ursula; Ahrens, Thomas; Miyake, Kensuke; Freudenberg, Marina; Galanos, Christopher; Simon, Jan Christoph

    2002-01-01

    Low molecular weight fragmentation products of the polysaccharide of Hyaluronic acid (sHA) produced during inflammation have been shown to be potent activators of immunocompetent cells such as dendritic cells (DCs) and macrophages. Here we report that sHA induces maturation of DCs via the Toll-like receptor (TLR)-4, a receptor complex associated with innate immunity and host defense against bacterial infection. Bone marrow–derived DCs from C3H/HeJ and C57BL/10ScCr mice carrying mutant TLR-4 alleles were nonresponsive to sHA-induced phenotypic and functional maturation. Conversely, DCs from TLR-2–deficient mice were still susceptible to sHA. In accordance, addition of an anti–TLR-4 mAb to human monocyte–derived DCs blocked sHA-induced tumor necrosis factor α production. Western blot analysis revealed that sHA treatment resulted in distinct phosphorylation of p38/p42/44 MAP-kinases and nuclear translocation of nuclear factor (NF)-κB, all components of the TLR-4 signaling pathway. Blockade of this pathway by specific inhibitors completely abrogated the sHA-induced DC maturation. Finally, intravenous injection of sHA-induced DC emigration from the skin and their phenotypic and functional maturation in the spleen, again depending on the expression of TLR-4. In conclusion, this is the first report that polysaccharide degradation products of the extracellular matrix produced during inflammation might serve as an endogenous ligand for the TLR-4 complex on DCs. PMID:11781369

  15. Toll-like receptor responses to Peste des petits ruminants virus in goats and water buffalo.

    PubMed

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

  16. 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

  17. Trichostatin A Protects Liver against Septic Injury through Inhibiting Toll-Like Receptor Signaling

    PubMed Central

    Kim, So-Jin; Park, Jin-Sook; Lee, Do-Won; Lee, Sun-Mee

    2016-01-01

    Sepsis, a serious clinical problem, is characterized by a systemic inflammatory response to infection and leads to organ failure. Toll-like receptor (TLR) signaling is intimately implicated in hyper-inflammatory responses and tissue injury during sepsis. Histone deacetylase (HDAC) inhibitors have been reported to exhibit anti-inflammatory properties. The aim of this study was to investigate the hepatoprotective mechanisms of trichostatin A (TSA), a HDAC inhibitor, associated with TLR signaling pathway during sepsis. The anti-inflammatory properties of TSA were assayed in lipopolysaccharide (LPS)-stimulated RAW264.7 cells. Polymicrobial sepsis was induced in mice by cecal ligation and puncture (CLP), a clinically relevant model of sepsis. The mice were intraperitoneally received TSA (1, 2 or 5 mg/kg) 30 min before CLP. The serum and liver samples were collected 6 and 24-h after CLP. TSA inhibited the increased production of tumor necrosis factor (TNF)-α and interleukin (IL)-6 in LPS-stimulated RAW264.7 cells. TSA improved sepsis-induced mortality, attenuated liver injury and decreased serum TNF-α and IL-6 levels. CLP increased the levels of TLR4, TLR2 and myeloid differentiation primary response protein 88 (MyD88) protein expression and association of MyD88 with TLR4 and TLR2, which were attenuated by TSA. CLP increased nuclear translocation of nuclear factor kappa B and decreased cytosolic inhibitor of kappa B (IκB) protein expression, which were attenuated by TSA. Moreover, CLP decreased acetylation of IκB kinase (IKK) and increased association of IKK with IκB and TSA attenuated these alterations. Our findings suggest that TSA attenuates liver injury by inhibiting TLR-mediated inflammatory response during sepsis. PMID:27068262

  18. Insights into the Relationship between Toll Like Receptors and Gamma Delta T Cell Responses

    PubMed Central

    Dar, Asif Amin; Patil, Rushikesh Sudam; Chiplunkar, Shubhada Vivek

    2014-01-01

    The tumor microenvironment is an important aspect of cancer biology that contributes to tumor initiation, tumor progression and responses to therapy. The composition and characteristics of the tumor microenvironment vary widely and are important in determining the anti-tumor immune response. Successful immunization requires activation of both innate and adaptive immunity. Generally, immune system is compromised in patients with cancer due to immune suppression, loss of tumor antigen expression and dysfunction of antigen presenting cells (APC). Thus, therapeutic immunization leading to cancer regression remains a significant challenge. Certain cells of the immune system, including dendritic cells (DCs) and gamma delta (γδ) T cells are capable of driving potent anti-tumor responses. The property of MHC-unrestricted cytotoxicity, high potential of cytokine release, tissue tropism and early activation in infections and malignant disease makes γδ T cells as an emerging candidate for immunotherapy. Various strategies are being developed to enhance anti-tumor immune responses of γδ T cells and DCs one of them is the use of novel adjuvants like toll like receptors (TLR) agonists, which enhance γδ T cell function directly or through DC activation, which has ability to prime γδ T cells. TLR agonists are being used clinically either alone or in combination with tumor antigens and has shown initial success in both enhancing immune responses and eliciting anti-tumor activity. TLR activated γδ T cells and DCs nurture each other’s activation. This provides a potent base for first line of defense and manipulation of the adaptive response against pathogens and cancer. The available data provides a strong rationale for initiating combinatorial therapy for the treatment of diseases and this review will summarize the application of adjuvants (TLRs) for boosting immune response of γδ T cells to treat cancer and infectious diseases and their use in combinatorial therapy

  19. Activation of human and chicken toll-like receptors by Campylobacter spp.

    PubMed

    de Zoete, Marcel R; Keestra, A Marijke; Roszczenko, Paula; van Putten, Jos P M

    2010-03-01

    Campylobacter infection in humans is accompanied by severe inflammation of the intestinal mucosa, in contrast to colonization of chicken. The basis for the differential host response is unknown. Toll-like receptors (TLRs) sense and respond to microbes in the body and participate in the induction of an inflammatory response. Thus far, the interaction of Campylobacter with chicken TLRs has not been studied. Here, we investigated the potential of four Campylobacter strains to activate human TLR1/2/6, TLR4, TLR5, and TLR9 and chicken TLR2t2/16, TLR4, TLR5, and TLR21. Live bacteria showed no or very limited potential to activate TLR2, TLR4, and TLR5 of both the human and chicken species, with minor but significant differences between Campylobacter strains. In contrast, lysed bacteria induced strong NF-kappaB activation through human TLR1/2/6 and TLR4 and chicken TLR2t2/16 and TLR4 but not via TLR5 of either species. Interestingly, C. jejuni induced TLR4-mediated beta interferon in human but not chicken cells. Furthermore, isolated chromosomal Campylobacter DNA was unable to activate human TLR9 in our system, whereas chicken TLR21 was activated by DNA from all of the campylobacters tested. Our data are the first comparison of TLR-induced immune responses in humans and chickens. The results suggest that differences in bacterial cell wall integrity and in TLR responses to Campylobacter LOS and/or DNA may contribute to the distinct clinical manifestation between the species. PMID:20038539

  20. Activation of Human and Chicken Toll-Like Receptors by Campylobacter spp.▿

    PubMed Central

    de Zoete, Marcel R.; Keestra, A. Marijke; Roszczenko, Paula; van Putten, Jos P. M.

    2010-01-01

    Campylobacter infection in humans is accompanied by severe inflammation of the intestinal mucosa, in contrast to colonization of chicken. The basis for the differential host response is unknown. Toll-like receptors (TLRs) sense and respond to microbes in the body and participate in the induction of an inflammatory response. Thus far, the interaction of Campylobacter with chicken TLRs has not been studied. Here, we investigated the potential of four Campylobacter strains to activate human TLR1/2/6, TLR4, TLR5, and TLR9 and chicken TLR2t2/16, TLR4, TLR5, and TLR21. Live bacteria showed no or very limited potential to activate TLR2, TLR4, and TLR5 of both the human and chicken species, with minor but significant differences between Campylobacter strains. In contrast, lysed bacteria induced strong NF-κB activation through human TLR1/2/6 and TLR4 and chicken TLR2t2/16 and TLR4 but not via TLR5 of either species. Interestingly, C. jejuni induced TLR4-mediated beta interferon in human but not chicken cells. Furthermore, isolated chromosomal Campylobacter DNA was unable to activate human TLR9 in our system, whereas chicken TLR21 was activated by DNA from all of the campylobacters tested. Our data are the first comparison of TLR-induced immune responses in humans and chickens. The results suggest that differences in bacterial cell wall integrity and in TLR responses to Campylobacter LOS and/or DNA may contribute to the distinct clinical manifestation between the species. PMID:20038539

  1. [Platelets "Toll-like receptor" engagement stimulates the release of immunomodulating molecules].

    PubMed

    Cognasse, F; Hamzeh-Cognasse, H; Garraud, O

    2008-09-01

    Platelets are nonnucleated cellular elements that play a role in the process of haemostasis, and also in various ways in innate immunity and in inflammation. Platelets also contain numerous secretory products and can exert critical roles in several aspects of haemostasis. In addition, they house and secrete a variety of cytokines, chemokines and associated molecules which behave as ligands for receptors/counterparts displayed by endothelial cells lining tissue vessels and most leukocyte subsets. These latter studies show that platelets have an important role in innate as well as adaptive immunity; thus platelets can take part in an immune directive response. Moreover, platelets display receptors for several types of cytokines/chemokines along with FcgammaRII receptors. Finally, platelets not only express a variety of Toll-like receptors, with recently identified functions or not as-yet fully identified, but have also been demonstrated to express the key tandem pair of inflammatory and antigen presentation molecules (CD40 and CD40-ligand/CD154), this latter function making them the major purveyors of soluble CD40L in the plasma. It appears that platelets may be regarded as one of the neglected components of immune cell regulators, and platelets contribute to some interesting aspects in bridging innate and adaptive immunity. We propose that platelets discriminate danger signals and adapt the subsequent responses, with polarized cytokine secretion. Platelets may recognize several types of infectious pathogens and limit microbial colonization by sequestering these pathogens and releasing immunomodulatory factors. This review allows us to re-explore indications that platelets exert direct anti-infection immunity and we will present experimentally-driven arguments in favour of a role of platelet TLR in regulating certain immune activities.

  2. HIGH GLUCOSE INDUCES TOLL-LIKE RECEPTOR EXPRESSION IN HUMAN MONOCYTES: MECHANISM OF ACTIVATION

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Objective: Hyperglycemia induced inflammation is central in diabetes complications and monocytes are important in orchestrating these effects. Toll-like receptors (TLRs) play a key role in innate immune responses as well as inflammation. However, there is a paucity of data examining the expression a...

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  4. Toll Like Receptor-4 Mediates Vascular Inflammation and Insulin Resistance in Diet-Induced Obesity

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Vascular dysfunction is a major complication of metabolic disorders such as diabetes and obesity. The current studies were undertaken to determine if inflammatory responses are activated in the vasculature of mice with diet-induced obesity (DIO), and if so, whether Toll Like Receptor-4 (TLR4), a ke...

  5. CD200 restrains macrophage attack on oligodendrocyte precursors via toll-like receptor 4 downregulation.

    PubMed

    Hayakawa, Kazuhide; Pham, Loc-Duyen D; Seo, Ji Hae; Miyamoto, Nobukazu; Maki, Takakuni; Terasaki, Yasukazu; Sakadžić, Sava; Boas, David; van Leyen, Klaus; Waeber, Christian; Kim, Kyu-Won; Arai, Ken; Lo, Eng H

    2016-04-01

    There are numerous barriers to white matter repair after central nervous system injury and the underlying mechanisms remain to be fully understood. In this study, we propose the hypothesis that inflammatory macrophages in damaged white matter attack oligodendrocyte precursor cells via toll-like receptor 4 signaling thus interfering with this endogenous progenitor recovery mechanism. Primary cell culture experiments demonstrate that peritoneal macrophages can attack and digest oligodendrocyte precursor cells via toll-like receptor 4 signaling, and this phagocytosis of oligodendrocyte precursor cells can be inhibited by using CD200-Fc to downregulate toll-like receptor 4. In an in vivo model of white matter ischemia induced by endothelin-1, treatment with CD200-Fc suppressed toll-like receptor 4 expression in peripherally circulating macrophages, thus restraining macrophage phagocytosis of oligodendrocyte precursor cells and leading to improved myelination. Taken together, these findings suggest that deleterious macrophage effects may occur after white matter ischemia, whereby macrophages attack oligodendrocyte precursor cells and interfere with endogenous recovery responses. Targeting this pathway with CD200 may offer a novel therapeutic approach to amplify endogenous oligodendrocyte precursor cell-mediated repair of white matter damage in mammalian brain.

  6. Systemic cancer immunotherapy with Toll-like receptor 7 agonists: Timing is everything.

    PubMed

    Hotz, Christian; Bourquin, Carole

    2012-03-01

    Toll-like receptor (TLR) 7 agonists represent a promising strategy for the immunotherapy of cancer. We have recently investigated the influence of TLR tolerance on the efficacy of systemic tumor treatment with TLR7 ligands. We propose that considering the kinetics of receptor sensitivity highly improves the outcome of cancer immunotherapy. PMID:22720251

  7. Toll-like Receptors in Systemic Lupus Erythematosus Prospects for Therapeutic Intervention

    PubMed Central

    Kim, Wan-Uk; Sreih, Antoine; Bucala, Richard

    2009-01-01

    Recent experimental and clinical studies have placed new emphasis on the role of the innate immune system in SLE. Nucleic acid-containing immune complexes activate the innate response by engaging specific Toll-like receptors (TLRs) and promote the generation of autoantibodies. Pharmacologic modulation of TLR-directed pathways may offer new therapeutic approaches for the treatment of SLE. PMID:18722558

  8. Subclinical Congenital Cytomegalovirus Infection and Hearing Impairment

    ERIC Educational Resources Information Center

    Dahle, Arthur J.; And Others

    1974-01-01

    When the hearing sensitivity of children with subclinical congenital cytomegalovirus infection was evaluated and compared with that of a group of matched control subjects, nine of the 18 infected subjects were found to have some hearing loss, ranging from slight high-frequency impairments to a severe-to-profound unilateral loss. (MYS)

  9. Modulation of Immunoregulatory Properties of Mesenchymal Stromal Cells by Toll-Like Receptors: Potential Applications on GVHD

    PubMed Central

    2016-01-01

    In the last decade, the immunomodulatory properties of mesenchymal stromal cells (MSCs) have attracted a lot of attention, due to their potential applicability in the treatment of graft-versus-host disease (GVHD), a condition frequently associated with opportunistic infections. The present review addresses how Pathogen-Associated Molecular Patterns (PAMPS) modulate the immunosuppressive phenotype of human MSCs by signaling through Toll-like receptors (TLRs). Overall, we observed that regardless of the source tissue, human MSCs express TLR2, TLR3, TLR4, and TLR9. Stimulation of distinct TLRs on MSCs elicits distinct inflammatory signaling pathways, differentially influencing the expression of inflammatory factors and the ability of MSCs to suppress the proliferation of immune system cells. The capacity to enhance the immunosuppressive phenotype of MSCs through TLRs stimulation might be properly elucidated in order to improve the MSC-based immunotherapy against GVHD. PMID:27738438

  10. Functional Polymorphisms in Toll-like Receptor 4 Are Associated With Worse Outcome in Acute Ischemic Stroke Patients

    PubMed Central

    Weinstein, Jonathan R.; Schulze, Juliane; Lee, Richard V.; Phillips, Hunter; Zierath, Dannielle; Tanzi, Patricia; Shibata, Dean; Cain, Kevin C.; Becker, Kyra J.

    2014-01-01

    Toll-like receptor-4 (TLR4) is important in neuroinflammation. Single nucleotide polymorphisms (SNPs) in TLR4, including 1063 A/G [Asp299Gly] and 1363 C/T [Thr399Ile], are associated with altered immune responses but their effect on acute ischemic stroke (AIS) outcome is unknown. We collected demographic, clinical, laboratory, radiologic and genotype data on 113 AIS patients and performed multivariate analyses to assess associations between TLR4 SNP haplotype and either neurological outcome, infection or inflammatory markers. In adjusted analyses, TLR4 SNPs were associated with worse outcome as well as increases in circulating leukocytes, C-reactive protein and interleukin-1 receptor antagonist. In AIS, variations in TLR4 may influence neurological outcome. PMID:24784586

  11. From The Cover: Induction of antiviral immunity requires Toll-like receptor signaling in both stromal and dendritic cell compartments

    NASA Astrophysics Data System (ADS)

    Sato, Ayuko; Iwasaki, Akiko

    2004-11-01

    Pattern recognition by Toll-like receptors (TLRs) is known to be important for the induction of dendritic cell (DC) maturation. DCs, in turn, are critically important in the initiation of T cell responses. However, most viruses do not infect DCs. This recognition system poses a biological problem in ensuring that most viral infections be detected by pattern recognition receptors. Furthermore, it is unknown what, if any, is the contribution of TLRs expressed by cells that are infected by a virus, versus TLRs expressed by DCs, in the initiation of antiviral adaptive immunity. Here we address these issues using a physiologically relevant model of mucosal infection with herpes simplex virus type 2. We demonstrate that innate immune recognition of viral infection occurs in two distinct stages, one at the level of the infected epithelial cells and the other at the level of the noninfected DCs. Importantly, both TLR-mediated recognition events are required for the induction of effector T cells. Our results demonstrate that virally infected tissues instruct DCs to initiate the appropriate class of effector T cell responses and reveal the critical importance of the stromal cells in detecting infectious agents through their own pattern recognition receptors. mucosal immunity | pattern recognition | viral infection

  12. A systematic review of CD14 and toll-like receptors in relation to asthma in Caucasian children.

    PubMed

    Klaassen, Ester Mm; Thönissen, Brenda Ejt; van Eys, Guillaume; Dompeling, Edward; Jöbsis, Quirijn

    2013-03-15

    The aetiology of childhood asthma is complex. An early dysfunction in the immunological development of the innate immune system in combination with environmental factors possibly triggers asthma. CD14 and toll-like receptors are important components of the innate immune system. The aim of this systematic review was to obtain a better insight into the relation between CD14 and toll-like receptors and childhood asthma in Caucasians. We searched PubMed and EMBASE for relevant articles. In total, 44 articles were included. The quality of the selected studies was independently assessed by the first two authors using the Newcastle-Ottawa quality assessment scale. Toll-like receptor 2, toll-like receptor 6, toll-like receptor 9, and toll-like receptor 10 appear to have some association with childhood asthma in Caucasians. The evidence for a relation of CD14 with childhood asthma is limited. In conclusion, there is no convincing evidence yet for a role of CD14 and toll-like receptors in relation to childhood asthma. Future studies should include haplotype analysis and take environmental factors into account to further clarify the role of CD14 and toll-like receptors on childhood asthma.

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

    PubMed Central

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

    2014-01-01

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

  14. Characterization and expression analysis of Toll-like receptor 2 gene in large yellow croaker, Larimichthys crocea.

    PubMed

    Fan, Ze-Jun; Jia, Qiao-Jing; Yao, Cui-Luan

    2015-05-01

    Toll-like receptor 2 (TLR2) plays an important role in innate immune responses. Here we describe the isolation and characterization of the full-length cDNA sequence of toll-like receptor 2 in large yellow croaker Larimichthys crocea (LcTLR2). The LcTLR2 cDNA contains a 5'-terminal untranslated region (5'-UTR) of 135 bp, an open reading frame (ORF) of 2478 bp encoding a polypeptide of 825 amino acid residues and a 3'-UTR of 50 bp. Subcellular localization analysis suggested that the LcTLR2-pEGFP was mainly expressed in cytoplasm. Quantitative real-time reverse transcription PCR (qRT-PCR) analysis revealed a broad expression of LcTLR2 in most examined tissues, with the most predominant expression in blood, followed by spleen, and the weakest expression in stomach. The expression levels of LcTLR2 after injection with Vibrio parahaemolyticus, Lipopolysaccharides (LPS) and poly inosinic:cytidylic (polyI:C) were investigated in spleen, head-kidney and liver. Our results showed that LcTLR2 transcripts increased significantly after all the three immune challenges (p < 0.05). However, compared with polyI:C and LPS, higher expression levels of LcTLR2 were induced in all examined tissues after V. parahaemolyticus stimulation. In addition, the expression levels of LcTLR2 after flagellin, polyI:C, peptidoglycan (PGN) and LPS challenge in LCK were investigated, our findings showed that high LcTLR2 transcripts were induced after flagellin and PGN stimulation, suggesting that LcTLR2 might play a vital role in fish defense against bacterial infection. Furthermore, compared with LPS, flagellin and peptidoglycan might play an important role in LcTLR2 induction in large yellow croaker. PMID:25687392

  15. Identification and expression analysis of cobia (Rachycentron canadum) Toll-like receptor 9 gene.

    PubMed

    Byadgi, Omkar; Puteri, Dinda; Lee, Yan-Horn; Lee, Jai-Wei; Cheng, Ta-Chih

    2014-02-01

    Cobia culture is hindered by bacterial infection (Photobacterium damselae subsp. piscicida) and in order to study the effect of P. damselae subsp. piscicida challenge and CpG ODN stimulation on cobia Toll like receptor 9 (RCTLR9), we used PCR to clone RCTLR9 gene and qRT-PCR to quantify gene expression. The results indicated that RCTLR9 cDNA contains 3141 bp. It encodes 1047 amino acids containing 16 typical structures of leucine-rich repeats (LRRs) including an LRRTYP, LRRCT and a motif involved in PAMP binding was identified at position 240-253 amino acid. Broad expression of RCTLR9 was found in larval, juvenile and adult stages irrespective of the tissues. In larval stage, RCTLR9 mRNA expression decreased at 5 d and then increased at 10 dph. At juvenile stage cobia, the expression was significantly high (p < 0.05) in spleen and intestine compared to gill, kidney, liver and skin. However, at adult stage, the significant high expression was found in gill and intestine. Cobia challenged with P. damselae subsp. piscicida showed significant increase in RCTLR9 expression at 24 h post challenge in intestine, spleen and liver, while in kidney the expression was peak at 12 h and later it decreased at 24 h. The highest expression was 40 fold increase in spleen and the lowest expression was ∼3.6 fold increase in liver. Cobia stimulated with CpG oligonucleotides showed that the induction of these genes was CpG ODN type and time dependent. In spleen and liver, CpG ODNs 1668 and 2006 injected group showed high expression of RCTLR9, IL-1β, chemokine CC compared to other groups. Meanwhile, CpG ODN 2006 has induced high expression of IgM. The CpG ODNs 2395 have induced significant high expression of Mx in spleen and liver. These results demonstrates the potential of using CpG ODN to enhance cobia resistance to P. damselae subsp. piscicida infection and use as an adjuvant in vaccine development.

  16. Toll-like receptors expression and interferon-γ production by NK cells in human sepsis

    PubMed Central

    2012-01-01

    Introduction During the course of infection, natural killer (NK) cells contribute to innate immunity by producing cytokines, particularly interferon-gamma (IFN-γ). In addition to their beneficial effects against infection, NK cells may play a detrimental role during systemic inflammation, causing lethality during sepsis. Little is known on the immune status of NK cells in patients with systemic inflammatory response syndrome (SIRS) or sepsis in terms of cell surface markers expression and IFN-γ production. Methods We investigated 27 sepsis patients and 11 patients with non-infectious SIRS. CD56bright and CD56dim NK cell subsets were identified by flow cytometry and Toll-like receptor (TLR)2, TLR4, TLR9, CX3CR1, CD16 and CD69 expression were analyzed, as well as ex vivo IFN-γ production by NK cells in whole blood samples. Results We first showed that in NK cells from healthy controls, TLR2 and TLR4 expression is mainly intracellular, similarly to TLR9. Intracellular levels of TLR2 and TLR4, in both CD56bright and CD56dim NK cell subsets from sepsis patients, were increased compared to healthy subjects. In addition, the percentage of CD69+ cells was higher among NK cells of sepsis patients. No difference was observed for TLR9, CX3CR1, and CD16 expression. The ex vivo stimulation by TLR4 or TLR9 agonists, or whole bacteria in synergy with accessory cytokines (IL-15+IL-18), resulted in significant production of IFN-γ by NK cells of healthy controls. In contrast, for SIRS and sepsis patients this response was dramatically reduced. Conclusions This study reports for the first time an intracellular expression of TLR2 and TLR4 in human NK cells. Surface TLR4 expression allows discriminating sepsis and SIRS. Furthermore, during these pathologies, NK cells undergo an alteration of their immune status characterized by a profound reduction of their capacity to release IFN-γ. PMID:23098236

  17. Molecular cloning, characterization and expression of goose Toll-like receptor 5.

    PubMed

    Fang, Qiang; Pan, Zhiming; Geng, Shizhong; Kang, Xilong; Huang, Jinlin; Sun, Xiaolin; Li, Qiuchun; Cai, Yinqiang; Jiao, Xinan

    2012-10-01

    Toll-like receptors (TLRs) are pattern recognition receptors (PRRs) that are vital to activation of the innate immune system in response to invading pathogens through their recognition of pathogen-associated molecular patterns (PAMPs). TLR5 is responsible for the recognition of bacterial flagellin in vertebrates. In this study, we cloned the goose TLR5 gene using rapid amplification of cDNA ends (RACE). The open reading frame (ORF) of goose TLR5 cDNA is 2583 bp in length and encodes an 860 amino acid protein. The entire coding region of the TLR5 gene was successfully amplified from genomic DNA and contained a single exon. The putative amino acid sequence of goose TLR5 consisted of a signal peptide sequence, 11 leucine-rich repeat (LRR) domains, a leucine-rich repeat C-terminal (LRR-CT) domain, a transmembrane domain and an intracellular Toll-interleukin-1 receptor (TIR) domain. The amino acid sequence of goose TLR5 shared 50.5% identity with human (Homo sapiens), 49.8% with mouse (Mus musculus) and 82.7% with chicken (Gallus gallus). The goose TLR5 gene was highly expressed in the spleen, liver and brain; moderately expressed in PBMCs, kidney, lung, heart, bone marrow, small intestine and large intestine; and minimally expressed in the cecum. HEK293 cells transfected with goose TLR5 and NF-κB-luciferase containing plasmids significantly responded to flagellin from Salmonella typhimurium indicating that it is a functional TLR5 homologue. In response to infection with S. enterica serovar Enteritidis (SE), the level of TLR5 mRNA significantly increased over the control in PBMCs at 1 d post infection (p.i.) and was slightly elevated in the spleen at 1 d or 3 d p.i. IL-6 was expressed below control levels in PBMCs but was upregulated in the spleen. In contrast to IL-6, an evident decrease in the expression level of IL-8 was observed in both PBMCs and spleens at 1 d or 3 d p.i. SE challenge also resulted in an increase in the mRNA expression of IL-18 and IFN-γ in PBMCs

  18. A Comparative Analysis of the Mechanism of Toll-Like Receptor-Disruption by TIR-Containing Protein C from Uropathogenic Escherichia coli

    PubMed Central

    Waldhuber, Anna; Snyder, Greg A.; Römmler, Franziska; Cirl, Christine; Müller, Tina; Xiao, Tsan Sam; Svanborg, Catharina; Miethke, Thomas

    2016-01-01

    The TIR-containing protein C (TcpC) of uropathogenic Escherichia coli strains is a powerful virulence factor by impairing the signaling cascade of Toll-like receptors (TLRs). Several other bacterial pathogens like Salmonella, Yersinia, Staphylococcus aureus but also non-pathogens express similar proteins. We discuss here the pathogenic potential of TcpC and its interaction with TLRs and TLR-adapter proteins on the molecular level and compare its activity with the activity of other bacterial TIR-containing proteins. Finally, we analyze and compare the structure of bacterial TIR-domains with the TIR-domains of TLRs and TLR-adapters. PMID:26938564

  19. A systemic defect in Toll-like receptor 4 signaling increases lipopolysaccharide-induced suppression of IL-2-dependent T-cell proliferation in COPD.

    PubMed

    Knobloch, Jürgen; Chikosi, Sarah-Jane; Yanik, Sarah; Rupp, Jan; Jungck, David; Koch, Andrea

    2016-01-01

    The susceptibility to bacterial infections is increased in chronic obstructive pulmonary disease (COPD). This promotes exacerbations. IL-2 triggers CD4(+)/Th1-cell proliferation, which is important for infection defense. Bacterial endotoxin (LPS) activates MyD88/IRAK and TRIF/IKKε/TBK1 pathways via Toll-like receptor-4 (TLR4) in Th1 cells. Systemic defects in TLR pathways in CD4(+)/Th1 cells cause an impairment of IL-2-dependent immune responses to bacterial infections in COPD. Peripheral blood CD4(+) T cells of never smokers, smokers without COPD, and smokers with COPD (each n = 10) were ex vivo activated towards Th1 and stimulated with LPS. IL-2, MyD88, and TRIF expression, and cell proliferation was analyzed by ELISA, quantitative RT-PCR, and bromodeoxyuridine (BrdU) and trypan blue staining comparative among the cohorts. IL-2 release from activated T cells was increased in COPD vs. smokers and never smokers. LPS reduced IL-2 expression and T-cell proliferation. These effects were increased in COPD vs. never smokers and inversely correlated with FEV1 (%predicted). The MyD88/TRIF ratio was decreased in Th1 cells of COPD. The suppression of IL-2 by LPS was abolished by MyD88/IRAK blockade in never smokers but by TRIF/IKKε/TBK1 blockade in COPD. Moxifloxacin restored IL-2 expression and T-cell proliferation in the presence of LPS by blocking p38 MAPK. The increased IL-2 release from Th1 cells in COPD might contribute to airway inflammation in disease exacerbations. A switch from MyD88/IRAK to TRIF/IKKε/TBK1 signaling amplifies the suppression of IL-2-dependent proliferation of CD4(+) T cells by LPS in COPD. This molecular pathology is of systemic origin, might impair adaptive immune responses, and could explain the increased susceptibility to bacterial infections in COPD. Targeting TLR4-downstream signaling, for example, with moxifloxacin, might reduce exacerbation rates. PMID:26498252

  20. Salmonella enterica Serovar Typhimurium Exploits Toll-Like Receptor Signaling during the Host-Pathogen Interaction▿ †

    PubMed Central

    Wong, Christine E.; Sad, Subash; Coombes, Brian K.

    2009-01-01

    Salmonella survives and replicates in host cells by using a type III secretion system to evade host immune defenses. The innate immune system plays an important role as a first line of defense against pathogens and is mediated in part by Toll-like receptors (TLRs); however, the infection dynamics of Salmonella enterica serovar Typhimurium within macrophages stimulated with TLR ligands is poorly understood. We studied the infection dynamics of Salmonella in murine macrophages previously exposed to TLR ligands and report that treatment of macrophages with four different TLR agonists resulted in their increased phagocytic capacity toward Salmonella but not fluorescent microspheres. Further analysis revealed that the intracellular replication of Salmonella was enhanced in TLR-stimulated macrophages in a manner requiring a functional type III secretion system and enhanced transcriptional activity of the sseA virulence gene operon. Studies of mice that normally resolve an acute primary infection with Salmonella revealed that pretreatment of animals with CpG DNA had a detrimental effect on disease outcome. CpG-treated mice infected with Salmonella all succumbed to infection and had higher bacterial loads in the spleen than did control animals. These data suggest that Salmonella can exploit macrophages activated via the innate immune system for increased intracellular survival. PMID:19720755

  1. Interferon-γ mediates anemia but is dispensable for Fulminant Toll-Like Receptor 9-induced Macrophage Activation Syndrome and Hemophagocytosis

    PubMed Central

    Canna, Scott W.; Wrobel, Julia; Chu, Niansheng; Kreiger, Portia A.; Paessler, Michele; Behrens, Edward M.

    2013-01-01

    Objective Macrophage Activation Syndrome (MAS) is a devastating cytokine storm syndrome complicating many inflammatory diseases and characterized by fever, pancytopenia, and systemic inflammation. It is clinically similar to Hemophagocytic Lymphohistiocytosis (HLH), which is caused by viral infection of a host with impaired cellular cytotoxicity. Murine models of MAS and HLH illustrate Interferon-γ (IFN-γ) as the driving stimulus for hemophagocytosis and immunopathology. We sought to understand the inflammatory contributors to a murine model of Toll-like Receptor 9 (TLR9)-induced fulminant MAS. Methods Wild-type (WT), transgenic, and cytokine-inhibited mice were treated with an IL-10 receptor blocking antibody and TLR9 agonist, and parameters of MAS were evaluated. Results Fulminant MAS was characterized by dramatic elevations in IFN-γ, IL-12, and IL-6. Serum IFN-γ correlated with enhanced IFN-γ production within some hepatic populations, but fewer IFN-γ+ cells. Surprisingly, IFN-γKO mice developed immunopathology and hemophagocytosis comparably to WT mice. However, IFN-γKO mice did not become anemic and had greater numbers of splenic erythroid precursors. IL-12 neutralization phenocopied disease in IFN-γKO mice. Interestingly, Type I interferons contributed to the severity of hypercytokinemia and weight loss, but their absence did not otherwise affect MAS manifestations. Conclusion These data demonstrate that both fulminant MAS and hemophagocytosis can arise independently of IFN-γ, IL-12, or Type I interferons. They also suggest that IFN-γ-mediated dyserythropoiesis, not hemophagocytosis, is the dominant cause of anemia in fulminant TLR9-MAS. Thus, our data establish a novel mechanism for the acute anemia of inflammation, but suggest that a variety of triggers can result in hemophagocytic disease. PMID:23553372

  2. The immunologically active oligosaccharides isolated from wheatgrass modulate monocytes via Toll-like receptor-2 signaling.

    PubMed

    Tsai, Chia-Che; Lin, Chih-Ru; Tsai, Hsien-Yu; Chen, Chia-Jung; Li, Wen-Tai; Yu, Hui-Ming; Ke, Yi-Yu; Hsieh, Wei-Ying; Chang, Cheng-Yen; Wu, Ying-Ta; Wu, Chung-Yi; Chen, Shui-Tein; Wong, Chi-Huey

    2013-06-14

    Wheatgrass is one of the most widely used health foods, but its functional components and mechanisms remain unexplored. Herein, wheatgrass-derived oligosaccharides (WG-PS3) were isolated and found to induce CD69 and Th1 cytokine expression in human peripheral blood mononuclear cells. In particular, WG-PS3 directly activated the purified monocytes by inducing the expression of CD69, CD80, CD86, IL-12, and TNF-α but affected NK and T cells only in the presence of monocytes. After further purification and structural analysis, maltoheptaose was identified from WG-PS3 as an immunomodulator. Maltoheptaose activated monocytes via Toll-like receptor 2 (TLR-2) signaling, as discovered by pretreatment of blocking antibodies against Toll-like receptors (TLRs) and also determined by click chemistry. This study is the first to reveal the immunostimulatory component of wheatgrass with well defined molecular structures and mechanisms. PMID:23629653

  3. The potential for Toll-like receptors to collaborate with other innate immune receptors

    PubMed Central

    Mukhopadhyay, Subhankar; Herre, Jurgen; Brown, Gordon D; Gordon, Siamon

    2004-01-01

    Cells of the innate immune system express a large repertoire of germ-line encoded cell-surface glycoprotein receptors including Toll-like receptors (TLRs). TLRs recognize conserved motifs on microbes and induce inflammatory signals. Evidence suggests that individual members of the TLR family or other non-TLR surface antigens either physically or functionally interact with each other and cumulative effects of these interactions instruct the nature and outcome of the immune response to a particular pathogen. PMID:15270722

  4. Activation of lung toll-like receptors does not exacerbate sickness responses to lipopolysaccharide in mice.

    PubMed

    Walker, Adam K; Hsieh, Jennifer; Luu, Katherine V; Radwan, Aiat A; Valverde, Gabriella R; Dickey, Burton F; Tuvim, Michael J; Dantzer, Robert

    2014-05-01

    Pneumonia represents a leading cause of death. Recently, a novel treatment strategy for pneumonia has involved enhancing the host pulmonary innate immune response by pre-exposure to aerosolized toll-like receptor (TLR)9 and TLR2/6 agonists, known as O/P. O/P inhalation in mice has been demonstrated to stimulate innate lung immunity, and thus increase survival against subsequent pneumonia infection while producing barely detectable increases in systemic cytokines. Here, we examined the safety of O/P treatment when used in mice that are inflamed systemically. Swiss-Webster mice were treated with two doses of aerosolized O/P (1× or 8×) vs phosphate buffered saline (PBS) either immediately before intraperitoneal injection of 0.1mg/kg lipopolysaccharide (LPS) or PBS (equivolume) or 2h after. Sickness responses (reduced body weight, food intake, activity and social interaction) were examined at 2 and 5.5h post-treatment. Immediately following behavioral testing, mice were euthanized, perfused with PBS, and brains, spleens, livers and lungs snap frozen for assessment of pro-inflammatory cytokine mRNAs. While O/P treatment alone increased lung IL-1β, IFNγ and TNF-α, no such effects were observed in the brain, spleen or liver. Furthermore, there was no evidence that O/P treatment administered before or after LPS had any synergizing effect to potentiate the cytokine response to LPS in any compartment measured. Supportive of these findings were the measures of sickness behaviors that did not show any increased sickness response in O/P-treated mice exposed to LPS, suggestive that the cytokine signal produced in the lungs from O/P inhalation did not propagate to the brain and synergize with LPS-induced neuroinflammation. These findings support the safety of the use of O/P inhalation as a preventative measure against pneumonia and demonstrate a unique ability of the lungs to compartmentalize pulmonary inflammation and limit propagation of the cytokine signal to the brain.

  5. Detection of Neu1 Sialidase Activity in Regulating TOLL-like Receptor Activation

    PubMed Central

    Abdulkhalek, Samar

    2010-01-01

    Mammalian Toll-like receptors (TLRs) are a family of receptors that recognize pathogen-associated molecular patterns. Not only are TLRs crucial sensors of microbial (e.g., viruses, bacteria and parasite) infections, they also play an important role in the pathophysiology of infectious diseases, inflammatory diseases, and possibly in autoimmune diseases. Thus, the intensity and duration of TLR responses against infectious diseases must be tightly controlled. It follows that understanding the structural integrity of sensor receptors, their ligand interactions and signaling components is essential for subsequent immunological protection. It would also provide important opportunities for disease modification through sensor manipulation. Although the signaling pathways of TLR sensors are well characterized, the parameters controlling interactions between the sensors and their ligands still remain poorly defined. We have recently identified a novel mechanism of TLR activation by its natural ligand, which has not been previously observed 1,2. It suggests that ligand-induced TLR activation is tightly controlled by Neu1 sialidase activation. We have also reported that Neu1 tightly regulates neurotrophin receptors like TrkA and TrkB 3, which involve Neu1 and matrix metalloproteinase-9 (MMP-9) cross-talk in complex with the receptors 4. The sialidase assay has been initially use to find a novel ligand, thymoquinone, in the activation of Neu4 sialidase on the cell surface of macrophages, dendritic cells and fibroblast cells via GPCR Gαi proteins and MMP-9 5. For TLR receptors, our data indicate that Neu1 sialidase is already in complex with TLR-2, -3 and -4 receptors, and is induced upon ligand binding to either receptor. Activated Neu1 sialidase hydrolyzes sialyl α-2,3-linked β-galactosyl residues distant from ligand binding to remove steric hinderance to TLR-4 dimerization, MyD88/TLR4 complex recruitment, NFkB activation and pro-inflammatory cell responses. In a

  6. Serine dipeptide lipids of Porphyromonas gingivalis inhibit osteoblast differentiation: Relationship to Toll-like receptor 2.

    PubMed

    Wang, Yu-Hsiung; Nemati, Reza; Anstadt, Emily; Liu, Yaling; Son, Young; Zhu, Qiang; Yao, Xudong; Clark, Robert B; Rowe, David W; Nichols, Frank C

    2015-12-01

    Porphyromonas gingivalis is a periodontal pathogen strongly associated with loss of attachment and supporting bone for teeth. We have previously shown that the total lipid extract of P. gingivalis inhibits osteoblast differentiation through engagement of Toll-like receptor 2 (TLR2) and that serine dipeptide lipids of P. gingivalis engage both mouse and human TLR2. The purpose of the present investigation was to determine whether these serine lipids inhibit osteoblast differentiation in vitro and in vivo and whether TLR2 engagement is involved. Osteoblasts were obtained from calvaria of wild type or TLR2 knockout mouse pups that also express the Col2.3GFP transgene. Two classes of serine dipeptide lipids, termed Lipid 654 and Lipid 430, were tested. Osteoblast differentiation was monitored by cell GFP fluorescence and osteoblast gene expression and osteoblast function was monitored as von Kossa stained mineral deposits. Osteoblast differentiation and function were evaluated in calvarial cell cultures maintained for 21 days. Lipid 654 significantly inhibited GFP expression, osteoblast gene expression and mineral nodule formation and this inhibition was dependent on TLR2 engagement. Lipid 430 also significantly inhibited GFP expression, osteoblast gene expression and mineral nodule formation but these effects were only partially attributed to engagement of TLR2. More importantly, Lipid 430 stimulated TNF-α and RANKL gene expression in wild type cells but not in TLR2 knockout cells. Finally, osteoblast cultures were observed to hydrolyze Lipid 654 to Lipid 430 and this likely occurs through elevated PLA2 activity in the cultured cells. In conclusion, our results show that serine dipeptide lipids of P. gingivalis inhibit osteoblast differentiation and function at least in part through engagement of TLR2. The Lipid 430 serine class also increased the expression of genes that could increase osteoclast activity. We conclude that Lipid 654 and Lipid 430 have the potential

  7. Interaction between Cannabinoid System and Toll-Like Receptors Controls Inflammation

    PubMed Central

    2016-01-01

    Since the discovery of the endocannabinoid system consisting of cannabinoid receptors, endogenous ligands, and biosynthetic and metabolizing enzymes, interest has been renewed in investigating the promise of cannabinoids as therapeutic agents. Abundant evidence indicates that cannabinoids modulate immune responses. An inflammatory response is triggered when innate immune cells receive a danger signal provided by pathogen- or damage-associated molecular patterns engaging pattern-recognition receptors. Toll-like receptor family members are prominent pattern-recognition receptors expressed on innate immune cells. Cannabinoids suppress Toll-like receptor-mediated inflammatory responses. However, the relationship between the endocannabinoid system and innate immune system may not be one-sided. Innate immune cells express cannabinoid receptors and produce endogenous cannabinoids. Hence, innate immune cells may play a role in regulating endocannabinoid homeostasis, and, in turn, the endocannabinoid system modulates local inflammatory responses. Studies designed to probe the interaction between the innate immune system and the endocannabinoid system may identify new potential molecular targets in developing therapeutic strategies for chronic inflammatory diseases. This review discusses the endocannabinoid system and Toll-like receptor family and evaluates the interaction between them.

  8. Interaction between Cannabinoid System and Toll-Like Receptors Controls Inflammation

    PubMed Central

    2016-01-01

    Since the discovery of the endocannabinoid system consisting of cannabinoid receptors, endogenous ligands, and biosynthetic and metabolizing enzymes, interest has been renewed in investigating the promise of cannabinoids as therapeutic agents. Abundant evidence indicates that cannabinoids modulate immune responses. An inflammatory response is triggered when innate immune cells receive a danger signal provided by pathogen- or damage-associated molecular patterns engaging pattern-recognition receptors. Toll-like receptor family members are prominent pattern-recognition receptors expressed on innate immune cells. Cannabinoids suppress Toll-like receptor-mediated inflammatory responses. However, the relationship between the endocannabinoid system and innate immune system may not be one-sided. Innate immune cells express cannabinoid receptors and produce endogenous cannabinoids. Hence, innate immune cells may play a role in regulating endocannabinoid homeostasis, and, in turn, the endocannabinoid system modulates local inflammatory responses. Studies designed to probe the interaction between the innate immune system and the endocannabinoid system may identify new potential molecular targets in developing therapeutic strategies for chronic inflammatory diseases. This review discusses the endocannabinoid system and Toll-like receptor family and evaluates the interaction between them. PMID:27597805

  9. Association of Toll-like receptors 2, 3, and 4 genes polymorphisms with periapical pathosis risk

    PubMed Central

    Özan, Ülkü; Ocak, Zeynep; Özan, Fatih; Oktay, Elif-Aybala; Şahman, Halil; Yikilgan, İhsan; Oruçoğlu, Hasan; Er, Kürşat

    2016-01-01

    Background The aim of this study was to investigate the role of gene variations of Toll-like receptors (TLR) 2, 3, and 4 on genetic susceptibility to periapical pathosis. Material and Methods One hundred patients were included in the study and divided into two groups as follows; Control Group (n=50) that have root canal treatment and no periapical lesion, Patient Group (n=50) that have root canal treatment and periapical lesion. TLR2 Arg753Gln, TLR3 (c.1377C/T) and TLR4 Asp299Gly and Thr399Ile polymorphisms were genotyped by using PCR-RFLP. Genotypical analysis of control and patient groups were investigated to disclose whether there is any association between periapical lesions and gene variations. Results There are no significant statistical differences between control and patient groups according to TLR 2 and 4 gene sequence. On the contrary, CC allele detected 74% for TLR 3 in patient group, and this difference was found to be statistically significant (p < 0.005). Conclusions According to these results, it can be suggested that patients with Toll-like receptor 3 gene polymorphisms could be susceptible to periapical pathosis. Key words:Toll-like receptors, periapical pathosis, endodontics. PMID:27031066

  10. Interaction between Cannabinoid System and Toll-Like Receptors Controls Inflammation.

    PubMed

    McCoy, Kathleen L

    2016-01-01

    Since the discovery of the endocannabinoid system consisting of cannabinoid receptors, endogenous ligands, and biosynthetic and metabolizing enzymes, interest has been renewed in investigating the promise of cannabinoids as therapeutic agents. Abundant evidence indicates that cannabinoids modulate immune responses. An inflammatory response is triggered when innate immune cells receive a danger signal provided by pathogen- or damage-associated molecular patterns engaging pattern-recognition receptors. Toll-like receptor family members are prominent pattern-recognition receptors expressed on innate immune cells. Cannabinoids suppress Toll-like receptor-mediated inflammatory responses. However, the relationship between the endocannabinoid system and innate immune system may not be one-sided. Innate immune cells express cannabinoid receptors and produce endogenous cannabinoids. Hence, innate immune cells may play a role in regulating endocannabinoid homeostasis, and, in turn, the endocannabinoid system modulates local inflammatory responses. Studies designed to probe the interaction between the innate immune system and the endocannabinoid system may identify new potential molecular targets in developing therapeutic strategies for chronic inflammatory diseases. This review discusses the endocannabinoid system and Toll-like receptor family and evaluates the interaction between them. PMID:27597805

  11. Controlling the cytokine storm in severe bacterial diarrhoea with an oral Toll-like receptor 4 antagonist.

    PubMed

    Islam, Dilara; Lombardini, Eric; Ruamsap, Nattaya; Imerbsin, Rawiwan; Khantapura, Patchariya; Teo, Ian; Neesanant, Pimmnapar; Gonwong, Siriphan; Yongvanitchit, Kosol; Swierczewski, Brett E; Mason, Carl J; Shaunak, Sunil

    2016-02-01

    Shigella dysenteriae causes the most severe of all infectious diarrhoeas and colitis. We infected rhesus macaques orally and also treated them orally with a small and non-absorbable polypropyletherimine dendrimer glucosamine that is a Toll-like receptor-4 (TLR4) antagonist. Antibiotics were not given for this life-threatening infection. Six days later, the clinical score for diarrhoea, mucus and blood was 54% lower, colon interleukin-8 and interleukin-6 were both 77% lower, and colon neutrophil infiltration was 75% less. Strikingly, vasculitis did not occur and tissue fibrin thrombi were reduced by 67%. There was no clinical toxicity or adverse effect of dendrimer glucosamine on systemic immunity. This is the first report in non-human primates of the therapeutic efficacy of a small and orally bioavailable TLR antagonist in severe infection. Our results show that an oral TLR4 antagonist can enable controlled resolution of the infection-related-inflammatory response and can also prevent neutrophil-mediated gut wall necrosis in severe infectious diarrhoeas. PMID:26496144

  12. Controlling the cytokine storm in severe bacterial diarrhoea with an oral Toll-like receptor 4 antagonist.

    PubMed

    Islam, Dilara; Lombardini, Eric; Ruamsap, Nattaya; Imerbsin, Rawiwan; Khantapura, Patchariya; Teo, Ian; Neesanant, Pimmnapar; Gonwong, Siriphan; Yongvanitchit, Kosol; Swierczewski, Brett E; Mason, Carl J; Shaunak, Sunil

    2016-02-01

    Shigella dysenteriae causes the most severe of all infectious diarrhoeas and colitis. We infected rhesus macaques orally and also treated them orally with a small and non-absorbable polypropyletherimine dendrimer glucosamine that is a Toll-like receptor-4 (TLR4) antagonist. Antibiotics were not given for this life-threatening infection. Six days later, the clinical score for diarrhoea, mucus and blood was 54% lower, colon interleukin-8 and interleukin-6 were both 77% lower, and colon neutrophil infiltration was 75% less. Strikingly, vasculitis did not occur and tissue fibrin thrombi were reduced by 67%. There was no clinical toxicity or adverse effect of dendrimer glucosamine on systemic immunity. This is the first report in non-human primates of the therapeutic efficacy of a small and orally bioavailable TLR antagonist in severe infection. Our results show that an oral TLR4 antagonist can enable controlled resolution of the infection-related-inflammatory response and can also prevent neutrophil-mediated gut wall necrosis in severe infectious diarrhoeas.

  13. Toll-like receptor 3 regulates cord blood-derived endothelial cell function in vitro and in vivo.

    PubMed

    Grelier, Aurore; Cras, Audrey; Balitrand, Nicole; Delmau, Catherine; Lecourt, Séverine; Lepelletier, Yves; Riesterer, Hélène; Freida, Delphine; Lataillade, Jean-Jacques; Lebousse-Kerdiles, Marie-Caroline; Cuccini, Wendy; Peffault de Latour, Regis; Marolleau, Jean-Pierre; Uzan, Georges; Larghero, Jérôme; Vanneaux, Valérie

    2013-10-01

    Circulating endothelial progenitor cells (cEPC) are capable of homing to neovascularisation sites, in which they proliferate and differentiate into endothelial cells. Transplantation of cEPC-derived cells, in particular those isolated from umbilical cord blood (UCB), has emerged as a promising approach in the treatment of cardio-vascular diseases. After in vivo transplantation, these cells may be exposed to local or systemic inflammation or pathogens, of which they are a common target. Because Toll-like receptors (TLR) are critical in detecting pathogens and in initiating inflammatory responses, we hypothesized that TLR may govern UCB cEPC-derived cells function. While these cells expressed almost all TLR, we found that only TLR3 dramatically impaired cell properties. TLR3 activation inhibited cell proliferation, modified cell cycle entry, impaired the in vitro angiogenic properties and induced pro-inflammatory cytokines production. The anti-angiogenic effect of TLR3 activation was confirmed in vivo in a hind-limb ischemic mice model. Moreover, TLR3 activation consistently leads to an upregulation of miR-29b, -146a and -155 and to a deregulation of cytoskeleton and cell cycle regulator. Hence, TLR3 activation is likely to be a key regulator of cEPC-derived cells properties.

  14. Sleep Deprivation and Divergent Toll-like Receptor-4 Activation of Cellular Inflammation in Aging

    PubMed Central

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

    2015-01-01

    Objectives: 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. Design, Setting, and Participants: 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. Measurement and Results: 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). Conclusion: 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. Citation: Carroll JE, Carrillo C, Olmstead R, Witarama T, Breen EC, Yokomizo M, Seeman TE, Irwin MR. Sleep deprivation and divergent toll-like receptor-4 activation of cellular inflammation in aging. SLEEP

  15. Skewed pattern of Toll-like receptor 4-mediated cytokine production in human neonatal blood: Low LPS-induced IL-12p70 and high IL-10 persist throughout the first month of life

    PubMed Central

    Belderbos, M.E.; van Bleek, G.M.; Levy, O.; Blanken, M.O.; Houben, M.L.; Schuijff, L.; Kimpen, J.L.L.; Bont, L.

    2010-01-01

    Newborns are highly susceptible to infectious diseases, which may be due to impaired immune responses. This study aims to characterize the ontogeny of neonatal TLR-based innate immunity during the first month of life. Cellularity and Toll-like receptor (TLR) agonist-induced cytokine production were compared between cord blood obtained from healthy neonates born after uncomplicated gestation and delivery (n=18), neonatal venous blood obtained at the age of one month (n=96), and adult venous blood (n=17). Cord blood TLR agonist-induced production of the Th1-polarizing cytokines IL-12p70 and IFN-α was generally impaired, but for TLR3, 7 and 9 agonists, rapidly increased to adult levels during the first month of life. In contrast, TLR4 demonstrated a slower maturation, with low LPS-induced IL-12p70 production and high IL-10 production up until the age of one month. Polarization in neonatal cytokine responses to LPS could contribute to neonatal susceptibility to severe bacterial infection. PMID:19648060

  16. TOLL-LIKE RECEPTORS (TLR) 2 AND 4 EXPRESSION OF KERATINOCYTES FROM PATIENTS WITH LOCALIZED AND DISSEMINATED DERMATOPHYTOSIS

    PubMed Central

    de Oliveira, Cristiane Beatriz; Vasconcellos, Cídia; Sakai-Valente, Neusa Y.; Sotto, Mirian Nacagami; Luiz, Fernanda Guedes; Belda, Walter; de Sousa, Maria da Gloria Teixeira; Benard, Gil; Criado, Paulo Ricardo

    2015-01-01

    There are few studies on the role of innate immune response in dermatophytosis. An investigation was conducted to define the involvement of Toll-Like Receptors (TLRs) 2 and 4 in localized (LD) and disseminated (DD) dermatophytosis due to T. rubrum. Fifteen newly diagnosed patients, eight patients with LD and seven with DD, defined by involvement of at least three body segments were used in this study. Controls comprised twenty skin samples from healthy individuals undergoing plastic surgery. TLR2 and TLR4 were quantified in skin lesions by immunohistochemistry. A reduced expression of TLR4 in the lower and upper epidermis of both LD and DD patients was found compared to controls; TLR2 expression was preserved in the upper and lower epidermis of all three groups. As TLR4 signaling induces the production of inflammatory cytokines and neutrophils recruitment, its reduced expression likely contributed to the lack of resolution of the infection and the consequent chronic nature of the dermatophytosis. As TLR2 expression acts to limit the inflammatory process and preserves the epidermal structure, its preserved expression may also contribute to the persistent infection and limited inflammation that are characteristic of dermatophytic infections. PMID:25651327

  17. Mast cell toll-like receptor 2 signaling is crucial for effective killing of Francisella tularensis1

    PubMed Central

    Rodriguez, Annette R.; Yu, Jieh-Juen; Guentzel, M. N.; Navara, Christopher S.; Klose, Karl E.; Forsthuber, Thomas G.; Chambers, James P.; Berton, Michael T.; Arulanandam, Bernard P

    2012-01-01

    Toll-like receptor (TLR) signaling is critical for early host defense against pathogens, but the contribution of mast cell TLR-mediated mechanisms and subsequent effector functions during pulmonary infection is largely unknown. We have previously demonstrated that mast cells, through the production of IL-4, effectively control Francisella tularensis replication. In this study, the highly human virulent strain of F. tularensis SCHU S4 and the Live Vaccine Strain (LVS) were utilized to investigate the contribution of mast cell-TLR regulation of Francisella. Mast cells required TLR2 for effective bacterial killing, regulation of the hydrolytic enzyme cathepsin L, and for coordination and trafficking of MHCII and lysosomal associated membrane protein 2 (LAMP2). Infected TLR2−/− mast cells, in contrast to WT and TLR4−/−, lacked detectable IL-4 and displayed increased cell death with a 2–3 log increase of F. tularensis replication, but could be rescued with recombinant IL-4 treatment. Importantly, MHCII and LAMP2 localization with labeled F. tularensis in the lungs was greater in WT than in TLR2−/− mice. These results provide evidence for the important effector contribution of mast cells and TLR2-mediated signaling on early innate processes in the lung following pulmonary F. tularensis infection and provide additional insight into possible mechanisms by which intracellular pathogens modulate respiratory immune defenses. PMID:22529298

  18. Molecular characterization and functional analysis of Toll-like receptor 3 gene in orange-spotted grouper (Epinephelus coioides).

    PubMed

    Lin, Kebing; Ge, Hui; Lin, Qi; Wu, Jianshao; He, Libin; Fang, Qiongshan; Zhou, Chen; Sun, Minqiu; Huang, Zhongchi

    2013-09-15

    Toll-like receptor 3 (TLR3) plays an important role in activating innate immune responses during viral infection. In this report, TLR3 (EcTLR3) was characterized and analyzed for the first time in Epinephelus coioides. The full-length EcTLR3 cDNA is predicted to encode a 909 amino acid polypeptide that contains a signal peptide sequence, 18 leucine-rich repeat (LRR) motifs, a transmembrane region and a Toll/interleukin-1 receptor (TIR) domain. Quantitative real-time PCR revealed that the EcTLR3 mRNA was much more abundant in the liver than in other immune organs, and that the expression levels were very low in hemocyte and muscle. During development of the grouper, the levels of EcTLR3 transcripts increased with age, with very low expression levels at the early stages of development. EcTLR3 mRNA levels were examined in the liver at different times after treatment with polyriboinosinic polyribocytidylic acid (Poly I:C), and in nervous necrosis virus (NNV)-infected larval groupers. The results suggested that EcTLR3 plays an important role in a fish's defense against viral infection. PMID:23792060

  19. Molecular characterization and functional analysis of Toll-like receptor 3 gene in orange-spotted grouper (Epinephelus coioides).

    PubMed

    Lin, Kebing; Ge, Hui; Lin, Qi; Wu, Jianshao; He, Libin; Fang, Qiongshan; Zhou, Chen; Sun, Minqiu; Huang, Zhongchi

    2013-09-15

    Toll-like receptor 3 (TLR3) plays an important role in activating innate immune responses during viral infection. In this report, TLR3 (EcTLR3) was characterized and analyzed for the first time in Epinephelus coioides. The full-length EcTLR3 cDNA is predicted to encode a 909 amino acid polypeptide that contains a signal peptide sequence, 18 leucine-rich repeat (LRR) motifs, a transmembrane region and a Toll/interleukin-1 receptor (TIR) domain. Quantitative real-time PCR revealed that the EcTLR3 mRNA was much more abundant in the liver than in other immune organs, and that the expression levels were very low in hemocyte and muscle. During development of the grouper, the levels of EcTLR3 transcripts increased with age, with very low expression levels at the early stages of development. EcTLR3 mRNA levels were examined in the liver at different times after treatment with polyriboinosinic polyribocytidylic acid (Poly I:C), and in nervous necrosis virus (NNV)-infected larval groupers. The results suggested that EcTLR3 plays an important role in a fish's defense against viral infection.

  20. Space and time: New considerations about the relationship between Toll-like receptors (TLRs) and type I interferons (IFNs).

    PubMed

    Perkins, Darren J; Vogel, Stefanie N

    2015-08-01

    The Toll like receptors (TLRs) and the type I interferons have critical roles to play in innate immunity. In this review we will discuss new developments relating to the important area of TLR/IFN cross regulation.

  1. Space and Time: New Considerations About the Relationship Between Toll-like Receptors (TLRs) and Type I Interferons (IFNs)

    PubMed Central

    Perkins, Darren J.; Vogel, Stefanie N.

    2015-01-01

    The Toll Like Receptors (TLRs) and the type I Interferons have critical roles to play in innate immunity. In this review we will discuss new developments relating to the important area of TLR/IFN cross regulation PMID:25819430

  2. Bovine viral diarrhea virus type 2 impairs macrophage responsiveness to toll-like receptor ligation with the exception of toll-like receptor 7

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Bovine viral diarrhea virus (BVDV) is a member of the Flaviviradae family. BVDV isolates are classified into two biotypes based on the development of cytopathic (cp) or non-cytopathic (ncp) effects in epithelial cell culture. In addition, BVDV isolates are further separated into species, BVDV1 and 2...

  3. Interleukin-24 inhibits influenza A virus replication in vitro through induction of toll-like receptor 3 dependent apoptosis.

    PubMed

    Weiss, René; Laengle, Johannes; Sachet, Monika; Shurygina, Anna-Polina; Kiselev, Oleg; Egorov, Andrej; Bergmann, Michael

    2015-11-01

    New anti-viral agents and strategies are urgently needed to fight rapidly mutating viruses, as vaccine programs cannot react fast enough to prevent pandemics. Recently, we have shown that interleukin-24 (IL-24) sensitizes tumor cells to toll-like receptor 3 (TLR3) mediated apoptosis. As influenza A virus stimulates the TLR3 receptor, we hypothesized that IL-24 might also exert an anti-viral effect. This study demonstrates that IL-24 reduces the titer of different influenza A virus subtypes independently of type I interferon in an apoptosis dependent manner. The anti-viral effect of IL-24 correlated with caspase-3 activation and could be blocked by a pan-caspase inhibitor and by small interfering RNA (siRNA) directed towards TLR3. Surprisingly, caspase-3 activation in influenza A virus/IL-24-stimulated cells correlated with the down-regulation of the B-cell lymphoma 2 (Bcl-2) family member myeloid cell leukemia 1 (Mcl-1). Correspondingly, knockdown of Mcl-1 by siRNA enhanced caspase activation in influenza A virus infected cells and was furthermore linked to a reduction of viral titers. We conclude that IL-24 exerts an anti-viral role selectively purging virally infected cells by leading to a down-regulation of Mcl-1. Our findings might therefore represent the first step towards a new rational concept in the development of anti-viral strategies based on the induction of apoptosis. PMID:26367324

  4. Identification and characterization of toll-like receptors (TLRs) in the Chinese tree shrew (Tupaia belangeri chinensis).

    PubMed

    Yu, Dandan; Wu, Yong; Xu, Ling; Fan, Yu; Peng, Li; Xu, Min; Yao, Yong-Gang

    2016-07-01

    In mammals, the toll-like receptors (TLRs) play a major role in initiating innate immune responses against pathogens. Comparison of the TLRs in different mammals may help in understanding the TLR-mediated responses and developing of animal models and efficient therapeutic measures for infectious diseases. The Chinese tree shrew (Tupaia belangeri chinensis), a small mammal with a close relationship to primates, is a viable experimental animal for studying viral and bacterial infections. In this study, we characterized the TLRs genes (tTLRs) in the Chinese tree shrew and identified 13 putative TLRs, which are orthologs of mammalian TLR1-TLR9 and TLR11-TLR13, and TLR10 was a pseudogene in tree shrew. Positive selection analyses using the Maximum likelihood (ML) method showed that tTLR8 and tTLR9 were under positive selection, which might be associated with the adaptation to the pathogen challenge. The mRNA expression levels of tTLRs presented an overall low and tissue-specific pattern, and were significantly upregulated upon Hepatitis C virus (HCV) infection. tTLR4 and tTLR9 underwent alternative splicing, which leads to different transcripts. Phylogenetic analysis and TLR structure prediction indicated that tTLRs were evolutionarily conserved, which might reflect an ancient mechanism and structure in the innate immune response system. Taken together, TLRs had both conserved and unique features in the Chinese tree shrew. PMID:26923770

  5. Differential regulation of toll-like receptor-2, toll-like receptor-4, CD16 and human leucocyte antigen-DR on peripheral blood monocytes during mild and severe dengue fever

    PubMed Central

    Azeredo, Elzinandes L; Neves-Souza, Patrícia C; Alvarenga, Allan R; Reis, Sônia R N I; Torrentes-Carvalho, Amanda; Zagne, Sonia-Maris O; Nogueira, Rita M R; Oliveira-Pinto, Luzia M; Kubelka, Claire F

    2010-01-01

    Dengue fever (DF), a public health problem in tropical countries, may present severe clinical manifestations as result of increased vascular permeability and coagulation disorders. Dengue virus (DENV), detected in peripheral monocytes during acute disease and in in vitro infection, leads to cytokine production, indicating that virus–target cell interactions are relevant to pathogenesis. Here we investigated the in vitro and in vivo activation of human peripheral monocytes after DENV infection. The numbers of CD14+ monocytes expressing the adhesion molecule intercellular adhesion molecule 1 (ICAM-1) were significantly increased during acute DF. A reduced number of CD14+ human leucocyte antigen (HLA)-DR+ monocytes was observed in patients with severe dengue when compared to those with mild dengue and controls; CD14+ monocytes expressing toll-like receptor (TLR)2 and TLR4 were increased in peripheral blood from dengue patients with mild disease, but in vitro DENV-2 infection up-regulated only TLR2. Increased numbers of CD14+ CD16+ activated monocytes were found after in vitro and in vivo DENV-2 infection. The CD14high CD16+ monocyte subset was significantly expanded in mild dengue, but not in severe dengue. Increased plasma levels of tumour necrosis factor-α (TNF-α), interferon-γ (IFN-γ) and interleukin (IL)-18 in dengue patients were inversely associated with CD14high CD16+, indicating that these cells might be involved in controlling exacerbated inflammatory responses, probably by IL-10 production. We showed here, for the first time, phenotypic changes on peripheral monocytes that were characteristic of cell activation. A sequential monocyte-activation model is proposed in which DENV infection triggers TLR2/4 expression and inflammatory cytokine production, leading eventually to haemorrhagic manifestations, thrombocytopenia, coagulation disorders, plasmatic leakage and shock development, but may also produce factors that act in order to control both intense

  6. Differential regulation of toll-like receptor-2, toll-like receptor-4, CD16 and human leucocyte antigen-DR on peripheral blood monocytes during mild and severe dengue fever.

    PubMed

    Azeredo, Elzinandes L; Neves-Souza, Patrícia C; Alvarenga, Allan R; Reis, Sônia R N I; Torrentes-Carvalho, Amanda; Zagne, Sonia-Maris O; Nogueira, Rita M R; Oliveira-Pinto, Luzia M; Kubelka, Claire F

    2010-06-01

    Dengue fever (DF), a public health problem in tropical countries, may present severe clinical manifestations as result of increased vascular permeability and coagulation disorders. Dengue virus (DENV), detected in peripheral monocytes during acute disease and in in vitro infection, leads to cytokine production, indicating that virus-target cell interactions are relevant to pathogenesis. Here we investigated the in vitro and in vivo activation of human peripheral monocytes after DENV infection. The numbers of CD14(+) monocytes expressing the adhesion molecule intercellular adhesion molecule 1 (ICAM-1) were significantly increased during acute DF. A reduced number of CD14(+) human leucocyte antigen (HLA)-DR(+) monocytes was observed in patients with severe dengue when compared to those with mild dengue and controls; CD14(+) monocytes expressing toll-like receptor (TLR)2 and TLR4 were increased in peripheral blood from dengue patients with mild disease, but in vitro DENV-2 infection up-regulated only TLR2. Increased numbers of CD14(+) CD16(+) activated monocytes were found after in vitro and in vivo DENV-2 infection. The CD14(high) CD16(+) monocyte subset was significantly expanded in mild dengue, but not in severe dengue. Increased plasma levels of tumour necrosis factor-alpha (TNF-alpha), interferon-gamma (IFN-gamma) and interleukin (IL)-18 in dengue patients were inversely associated with CD14(high) CD16(+), indicating that these cells might be involved in controlling exacerbated inflammatory responses, probably by IL-10 production. We showed here, for the first time, phenotypic changes on peripheral monocytes that were characteristic of cell activation. A sequential monocyte-activation model is proposed in which DENV infection triggers TLR2/4 expression and inflammatory cytokine production, leading eventually to haemorrhagic manifestations, thrombocytopenia, coagulation disorders, plasmatic leakage and shock development, but may also produce factors that act in

  7. Toll-like receptor-4 mediates cigarette smoke-induced cytokine production by human macrophages

    PubMed Central

    Karimi, Khalil; Sarir, Hadi; Mortaz, Esmaeil; Smit, Joost J; Hosseini, Hossein; De Kimpe, Sjef J; Nijkamp, Frans P; Folkerts, Gert

    2006-01-01

    Background The major risk factor for the development of COPD is cigarette smoking. Smoking causes activation of resident cells and the recruitment of inflammatory cells into the lungs, which leads to release of pro-inflammatory cytokines, chemotactic factors, oxygen radicals and proteases. In the present study evidence is found for a new cellular mechanism that refers to a link between smoking and inflammation in lungs. Methods Employing human monocyte-derived macrophages, different techniques including FACS analysis, Cytometric Bead Array Assay and ELISA were achieved to evaluate the effects of CS on pro-inflammatory cytokine secretion including IL-8. Then, Toll-like receptor neutralization was performed to study the involvement of Toll-like receptor-4 in IL-8 production. Finally, signaling pathways in macrophages after exposure to CS medium were investigated performing ELISA and Western analysis. Results We demonstrate that especially human monocytes are sensitive to produce IL-8 upon cigarette smoke stimulation compared to lymphocytes or neutrophils. Moreover, monocyte-derived macrophages produce high amounts of the cytokine. The IL-8 production is dependent on Toll-like receptor 4 stimulation and LPS is not involved. Further research resolved the cellular mechanism by which cigarette smoke induces cytokine production in monocyte-derived macrophages. Cigarette smoke causes subsequently a concentration-dependent phosphorylation of IRAK and degradation of TRAF6. Moreover, IκBα was phosphorylated which suggests involvement of NF-κB. In addition, NFκB -inhibitor blocked cigarette smoke-induced IL-8 production. Conclusion These findings link cigarette smoke to inflammation and lead to new insights/therapeutic strategies in the pathogenesis of lung emphysema. PMID:16620395

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

    PubMed

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

    2016-01-01

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

  9. Trial Watch: Immunostimulation with Toll-like receptor agonists in cancer therapy

    PubMed Central

    Iribarren, Kristina; Bloy, Norma; Buqué, Aitziber; Cremer, Isabelle; Eggermont, Alexander; Fridman, Wolf Hervé; Fucikova, Jitka; Galon, Jérôme; Špíšek, Radek; Zitvogel, Laurence; Kroemer, Guido; Galluzzi, Lorenzo

    2016-01-01

    ABSTRACT Accumulating preclinical evidence indicates that Toll-like receptor (TLR) agonists efficiently boost tumor-targeting immune responses (re)initiated by most, if not all, paradigms of anticancer immunotherapy. Moreover, TLR agonists have been successfully employed to ameliorate the efficacy of various chemotherapeutics and targeted anticancer agents, at least in rodent tumor models. So far, only three TLR agonists have been approved by regulatory agencies for use in cancer patients. Moreover, over the past decade, the interest of scientists and clinicians in these immunostimulatory agents has been fluctuating. Here, we summarize recent advances in the preclinical and clinical development of TLR agonists for cancer therapy. PMID:27141345

  10. Toll-like receptor genes (TLRs) from Capitella capitata and Helobdella robusta (Annelida).

    PubMed

    Davidson, Charis R; Best, Natalie M; Francis, Joseph W; Cooper, Edwin L; Wood, Todd Charles

    2008-01-01

    Toll-like receptors (TLRs) are an important part of the innate immunity system and are found throughout the animal kingdom, but have not yet been reported in annelids. We searched shotgun reads of the genomes of the leech Helobdella and polychaete Capitella for TLR homologs. We found 105 TLR homologs in Capitella and 16 in Helobdella. The deduced phylogeny of these sequences, together with TLRs from other animal phyla, reveals three major clades. One clade consists of a mixture of both vertebrates and invertebrates, including sequences from Capitella and Helobdella, while the other two clades contain only invertebrate TLRs.

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

    PubMed Central

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

    2016-01-01

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

  12. Human Toll-like receptor 8 can be cool too: implications for foreign RNA sensing.

    PubMed

    Sarvestani, Soroush T; Williams, Bryan R G; Gantier, Michael P

    2012-08-01

    Recent advances in our understanding of foreign nucleic acid sensing indicate an important role for the human Toll-like receptor (TLR) 8 in the initiation of immune responses to certain pathogens. However, TLR8, far too often grouped together with TLR7 for its common ability to detect RNA, has a function on its own in the initiation of specific proinflammatory responses to viruses and bacteria. Here, we present an overview of what is currently known of human TLR8 biology, from genetic regulation to its function in innate immunity, and discuss how TLR8 could present novel therapeutic opportunities in viral and cancer diseases. PMID:22817608

  13. Toll-like receptors in the pathogenesis of autoimmune diseases: recent and emerging translational developments

    PubMed Central

    Duffy, Laura; O’Reilly, Steven C

    2016-01-01

    Autoinflammatory diseases are defined as the loss of self-tolerance in which an inflammatory response to self-antigens occurs, which are a significant global burden. Toll-like receptors are key pattern recognition receptors, which integrate signals leading to the activation of transcription factors and ultimately proinflammatory cytokines. Recently, it has become apparent that these are at the nexus of autoinflammatory diseases making them viable and attractive drug targets. The aim of this review was to evaluate the role of innate immunity in autoinflammatory conditions alongside the role of negative regulation while suggesting possible therapeutic targets. PMID:27579291

  14. Chronic helminth infections impair pneumococcal vaccine responses.

    PubMed

    Apiwattanakul, Nopporn; Thomas, Paul G; Iverson, Amy R; McCullers, Jonathan A

    2014-09-22

    Pneumonia is the leading killer of children and disproportionately affects developing countries. Vaccination campaigns against Streptococcus pneumoniae, the leading cause of pneumonia, have recently been launched with a new conjugate vaccine in Africa. Using a mouse model, we assessed the potential role that the high burden of helminth infections in the countries targeted for vaccine might have on vaccine effectiveness. Mice vaccinated with either commercial conjugate or purified polysaccharide vaccines had impaired antibody responses if they were chronically infected with Taenia crassiceps. This translated to increased susceptibility to pneumococcal pneumonia and high mortality compared to helminth-negative vaccinated animals, which were fully protected from disease and death. Antibodies taken from Taenia-infected, vaccinated mice were unable to effectively opsonize S. pneumoniae for killing by alveolar macrophages, and did not protect against pneumococcal challenge when adoptively transferred into naïve animals. These data may have implications for vaccination programs in countries endemic with helminths.

  15. Pre-treatment with Toll-like receptor 4 antagonist inhibits lipopolysaccharide-induced preterm uterine contractility, cytokines, and prostaglandins in rhesus monkeys

    PubMed Central

    Adams Waldorf, Kristina M.; Persing, David; Novy, Miles J.; Sadowsky, Drew W.; Gravett, Michael G.

    2009-01-01

    Intra-uterine infection, which occurs in the majority of early preterm births, triggers an immune response culminating in preterm labor. We hypothesized that blockade of lipopolysaccharide (LPS)-induced immune responses by a Toll-like receptor 4 antagonist (TLR4A) would prevent elevations in amniotic fluid (AF) cytokines, prostaglandins, and uterine contractility. Chronically catheterized rhesus monkeys at 128-147 days gestation received intra-amniotic infusions of either: 1) saline (n=6), 2) LPS (0.15-10μg; n=4), or 3) TLR4A pre-treatment with LPS (10 μg) one hour later (n=4). AF cytokines, prostaglandins, and uterine contractility were compared using oneway ANOVA with Bonferroni-adjusted pairwise comparisons. Compared to saline controls, LPS induced significant elevations in AF IL-8, TNF-α, PGE2, PGF2α, and uterine contractility (p<0.05). In contrast, TLR4A pre-treatment inhibited LPS-induced uterine activity and was associated with significantly lower AF IL-8, TNF-α, PGE2, and PGF2α versus LPS alone (p<0.05). Toll-like receptor antagonists, together with antibiotics, may delay or prevent infection-associated preterm birth. PMID:18187405

  16. Functional Toll-like receptor 4 expressed in lactotrophs mediates LPS-induced proliferation in experimental pituitary hyperplasia

    SciTech Connect

    Sabatino, María Eugenia; Sosa, Liliana del Valle; Petiti, Juan Pablo; Mukdsi, Jorge Humberto; Mascanfroni, Iván Darío; Pellizas, Claudia Gabriela; Gutiérrez, Silvina; Torres, Alicia Inés; De Paul, Ana Lucía

    2013-11-15

    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 lactotrophs 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 the PI3K

  17. Toll like receptor 2 knock-out attenuates carbon tetrachloride (CCl4)-induced liver fibrosis by downregulating MAPK and NF-κB signaling pathways.

    PubMed

    Ji, Lingling; Xue, Ruyi; Tang, Wenqing; Wu, Weibin; Hu, Tingting; Liu, Xijun; Peng, Xiaomin; Gu, Jianxin; Chen, She; Zhang, Si

    2014-06-01

    Innate immune signaling associated with Toll-like receptors (TLRs) is a key pathway involved in the progression of liver fibrosis. In this study, we reported that TLR2 is required for hepatic fibrogenesis induced by carbon tetrachloride (CCl4). After CCl4 treatment, TLR2(-/-) mice had reduced liver enzyme levels, diminished collagen deposition, decreased inflammatory infiltration and impaired activation of hepatic stellate cells (HSCs) than wild type (WT) mice. Furthermore, after CCl4 treatment, TLR2(-/-) mice demonstrated downregulated expression of profibrotic and proinflammatory genes and impaired mitogen-activated protein kinases (MAPK) and nuclear factor kappa B (NF-κB) activation than WT mice. Collectively, our data indicate that TLR2 deficiency protects against CCl4-induced liver fibrosis.

  18. Hymenolepis diminuta: analysis of the expression of Toll-like receptor genes (TLR2 and TLR4) in the small and large intestines of rats. Part II.

    PubMed

    Kosik-Bogacka, D I; Wojtkowiak-Giera, A; Kolasa, A; Czernomysy-Furowicz, D; Lanocha, N; Wandurska-Nowak, E; Salamatin, R; Jagodzinski, P P

    2013-10-01

    Toll-like receptors in the gastrointestinal tract can influence intestinal homeostasis and play a role in the repair and restitution of intestinal epithelium following tissue damage. In our previous study a statistically significant increase in the level of TLR4 and TLR2 gene expression was observed in rats in early stages of hymenolepidosis. Moreover, the immunopositive cell number and the intensity of immunohistochemical staining (indicating the presence of TLRs within intestinal epithelial cells) increased over the infection period. In this paper, we determined changes in the expression of TLR2 and TLR4 and the number of anaerobic intestinal commensal bacteria in Hymenolepis diminuta infected rats. In the isolated jejunum of infected rats at 16 days post infection (dpi), the expression of TLR4 and TLR2 was significantly higher than uninfected rats. In the colon, a statistically significantly increased expression of TLR2 was observed from 16 to 40 dpi, and TLR4 from 16 to 60 dpi. The jejunum and colon of infected rats contained Gram-negative bacteria (Escherichia coli), Gram-positive bacteria (Enterococcus, Streptococcus, Staphylococcus, Bacillus, Lactobacillus) and Candida. The total number of intestinal bacteria was higher in H. diminuta infected rats, but the observed microbiota had only minor effects on the expression of TLR2 and TLR4. Toll-like receptors play a role in maintaining epithelial barrier function in response to enteric pathogens and parasites. In our study, the alteration of TLR2 and TLR4 expression in the infected rats indicates the potential role of the innate immune system in the pathomechanism of this infection.

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

    PubMed

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

    2016-01-01

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

  20. Toll-Like Receptor-Dependent Immune Complex Activation of B Cells and Dendritic Cells.

    PubMed

    Moody, Krishna L; Uccellini, Melissa B; Avalos, Ana M; Marshak-Rothstein, Ann; Viglianti, Gregory A

    2016-01-01

    High titers of autoantibodies reactive with DNA/RNA molecular complexes are characteristic of autoimmune disorders such as systemic lupus erythematosus (SLE). In vitro and in vivo studies have implicated the endosomal Toll-like receptor 9 (TLR9) and Toll-like receptor 7 (TLR7) in the activation of the corresponding autoantibody producing B cells. Importantly, TLR9/TLR7-deficiency results in the inability of autoreactive B cells to proliferate in response to DNA/RNA-associated autoantigens in vitro, and in marked changes in the autoantibody repertoire of autoimmune-prone mice. Uptake of DNA/RNA-associated autoantigen immune complexes (ICs) also leads to activation of dendritic cells (DCs) through TLR9 and TLR7. The initial studies from our lab involved ICs formed by a mixture of autoantibodies and cell debris released from dying cells in culture. To better understand the nature of the mammalian ligands that can effectively activate TLR7 and TLR9, we have developed a methodology for preparing ICs containing defined DNA fragments that recapitulate the immunostimulatory activity of the previous "black box" ICs. As the endosomal TLR7 and TLR9 function optimally from intracellular acidic compartments, we developed a facile methodology to monitor the trafficking of defined DNA ICs by flow cytometry and confocal microscopy. These reagents reveal an important role for nucleic acid sequence, even when the ligand is mammalian DNA and will help illuminate the role of IC trafficking in the response.

  1. Toll-like receptor 2 ligands promote microglial cell death by inducing autophagy

    PubMed Central

    Arroyo, Daniela S.; Soria, Javier A.; Gaviglio, Emilia A.; Garcia-Keller, Constanza; Cancela, Liliana M.; Rodriguez-Galan, Maria C.; Wang, Ji Ming; Iribarren, Pablo

    2013-01-01

    Microglial cells are phagocytes in the central nervous system (CNS) and become activated in pathological conditions, resulting in microgliosis, manifested by increased cell numbers and inflammation in the affected regions. Thus, controlling microgliosis is important to prevent pathological damage to the brain. Here, we evaluated the contribution of Toll-like receptor 2 (TLR2) to microglial survival. We observed that activation of microglial cells with peptidoglycan (PGN) from Staphylococcus aureus and other TLR2 ligands results in cell activation followed by the induction of autophagy and autophagy-dependent cell death. In C57BL/6J mice, intracerebral injection of PGN increased the autophagy of microglial cells and reduced the microglial/macrophage cell number in brain parenchyma. Our results demonstrate a novel role of TLRs in the regulation of microglial cell activation and survival, which are important for the control of microgliosis and associated inflammatory responses in the CNS.—Arroyo, D. S., Soria, J. A., Gaviglio, E. A., Garcia-Keller, C., Cancela, L. M., Rodriguez-Galan, M. C., Wang, J. M., Iribarren, P. Toll-like receptor 2 ligands promote microglial cell death by inducing autophagy. PMID:23073832

  2. Induction of antiviral responses against avian influenza virus in embryonated chicken eggs with toll-like receptor ligands.

    PubMed

    Barjesteh, Neda; Brisbin, Jennifer T; Behboudi, Shahriar; Nagy, Éva; Sharif, Shayan

    2015-05-01

    Early responses against viruses, such as avian influenza virus (AIV), may be induced by Toll-like receptor (TLR) pathways. In the present study, an in ovo model was employed to study the antiviral activities of TLR ligands. It was hypothesized that administration of TLR ligands in ovo at the appropriate dose and time can reduce AIV titer in embryonated chicken eggs. Moreover, the study aimed to determine the mechanisms involved in the TLR-mediated antiviral responses in the chorioallantoic membrane (CAM). Embryonated eggs (10-14 day old) were treated with TLR2, 4, 7, and 21 ligands using different doses and times pre- and post-AIV infection. The results revealed that treatment of embryonated chicken eggs with TLR ligands reduced AIV replication. Further analysis showed that TLR ligands induced interferon (IFN)-γ and IFN stimulatory genes in the CAM, which may have played a role in the reduction of the AIV titer. The timing and dose of TLR ligands administration had significant impacts on the outcome of the treated eggs. In conclusion, the present study demonstrated that the in ovo route may be employed to determine the antiviral characteristics of TLR ligands against AIV.

  3. Vanadate from Air Pollutant Inhibits Hrs-Dependent Endosome Fusion and Augments Responsiveness to Toll-Like Receptors

    PubMed Central

    Zelnikar, Mojca; Benčina, Mojca; Jerala, Roman; Manček-Keber, Mateja

    2014-01-01

    There is a well-established association between exposure to air pollutants and pulmonary injuries. For example, metals found in ROFA (residual oil fly ash) increase susceptibility of mice as well as humans to microbial infections. In our research, we have found that vanadate substantially increased the response of several Toll-like receptors (TLRs) to stimulation with their ligands. Although vanadate caused generation of reactive oxygen species (ROS), the addition of ROS scavenger N-acetyl cysteine (NAC) had no effect on augmented lipopolysaccharide (LPS) stimulation. We further showed that vanadate inhibits endosome fusion. This effect was determined by measuring the size of endosomes, NF-κB activity and TLR4 degradation in Hrs (hepatocyte growth factor-regulated tyrosine kinase substrate) overexpressed cells. Moreover, we identified the role of Hrs phosphorylation in these processes. Based on our findings, we can conclude that vanadate potentiates TLR4 activity by increasing Hrs phosphorylation status, reducing the size of Hrs/TLR4-positive endosomes and impacting TLR4 degradation, thus contributing to the detrimental effects of air pollutants on human health. PMID:24901993

  4. Isolation of murine peritoneal macrophages to carry out gene expression analysis upon Toll-like receptors stimulation.

    PubMed

    Layoun, Antonio; Samba, Macha; Santos, Manuela M

    2015-01-01

    During infection and inflammation, circulating monocytes leave the bloodstream and migrate into tissues, where they differentiate into macrophages. Macrophages express surface Toll-like receptors (TLRs), which recognize molecular patterns conserved through evolution in a wide range of microorganisms. TLRs play a central role in macrophage activation which is usually associated with gene expression alteration. Macrophages are critical in many diseases and have emerged as attractive targets for therapy. In the following protocol, we describe a procedure to isolate murine peritoneal macrophages using Brewer's thioglycollate medium. The latter will boost monocyte migration into the peritoneum, accordingly this will raise macrophage yield by 10-fold. Several studies have been carried out using bone marrow, spleen or peritoneal derived macrophages. However, peritoneal macrophages were shown to be more mature upon isolation and are more stable in their functionality and phenotype. Thus, macrophages isolated from murine peritoneal cavity present an important cell population that can serve in different immunological and metabolic studies. Once isolated, macrophages were stimulated with different TLR ligands and consequently gene expression was evaluated.

  5. Identification of oxidative stress and Toll-like receptor 4 signaling as a key pathway of acute lung injury.

    PubMed

    Imai, Yumiko; Kuba, Keiji; Neely, G Greg; Yaghubian-Malhami, Rubina; Perkmann, Thomas; van Loo, Geert; Ermolaeva, Maria; Veldhuizen, Ruud; Leung, Y H Connie; Wang, Hongliang; Liu, Haolin; Sun, Yang; Pasparakis, Manolis; Kopf, Manfred; Mech, Christin; Bavari, Sina; Peiris, J S Malik; Slutsky, Arthur S; Akira, Shizuo; Hultqvist, Malin; Holmdahl, Rikard; Nicholls, John; Jiang, Chengyu; Binder, Christoph J; Penninger, Josef M

    2008-04-18

    Multiple lung pathogens such as chemical agents, H5N1 avian flu, or SARS cause high lethality due to acute respiratory distress syndrome. Here we report that Toll-like receptor 4 (TLR4) mutant mice display natural resistance to acid-induced acute lung injury (ALI). We show that TLR4-TRIF-TRAF6 signaling is a key disease pathway that controls the severity of ALI. The oxidized phospholipid (OxPL) OxPAPC was identified to induce lung injury and cytokine production by lung macrophages via TLR4-TRIF. We observed OxPL production in the lungs of humans and animals infected with SARS, Anthrax, or H5N1. Pulmonary challenge with an inactivated H5N1 avian influenza virus rapidly induces ALI and OxPL formation in mice. Loss of TLR4 or TRIF expression protects mice from H5N1-induced ALI. Moreover, deletion of ncf1, which controls ROS production, improves the severity of H5N1-mediated ALI. Our data identify oxidative stress and innate immunity as key lung injury pathways that control the severity of ALI.

  6. Possible evidence of systemic lupus erythematosus and periodontal disease association mediated by Toll-like receptors 2 and 4.

    PubMed

    Marques, C P C; Maor, Y; de Andrade, M S; Rodrigues, V P; Benatti, B B

    2016-02-01

    Toll-like receptors (TLRs) participate in the innate immune response and trigger the immune responses of the body. Systemic lupus erythematosus (SLE) is an autoimmune disease of unknown aetiology, characterized by an excessive autoimmune response in the body affecting the connective tissues. The disease is possibly triggered by both environmental aetiological factors and pathological organic processes such as exposure to sunlight, chronic infectious processes and genetic factors. Conversely, periodontal disease is an infectious disease caused by microorganisms in the oral cavity, resulting in a chronic inflammatory process which continuously stimulates the immune response, thus causing damage to the periodontal tissues. The expression of both TLR-2 and TLR-4 receptors are increased in both SLE and periodontal disease. Periodontitis might trigger excessive activation of immune response occurring in SLE by maintaining a high expression of TLRs, leading in turn to the acceleration of the onset and progression of autoimmune reactions. In addition, periodontal treatment is able to reduce the expression of these receptors and therefore the symptoms of SLE. Here we discuss the possible interaction between SLE and periodontitis, and suggest further studies evaluating common features in both factors that could explored, due to morbidity and mortality of SLE and the high incidence of periodontal infections around the world. PMID:26386242

  7. Antiviral Responses of Human Fallopian Tube Epithelial Cells to Toll-like Receptor 3 Agonist Poly(I:C)

    PubMed Central

    Ghosh, Mimi; Schaefer, Todd M.; Fahey, John V.; Wright, Jacqueline A.; Wira, Charles R.

    2009-01-01

    Objective To examine the expression of toll-like receptors (TLR) by primary human Fallopian tube epithelial cells (FTEC) and to determine whether exposure to the TLR3 agonist poly(I:C) would induce an antiviral response. Design Tissue culture study. Setting University Medical Center. Patient(s) Pre-menopausal women undergoing hysterectomy. Intervention(s) Primary human FTEC were grown to confluence and high transepithelial resistance and treated with TLR agonists. Conditioned media was collected and RNA was extracted and analyzed for the expression of cytokines, chemokines and antimicrobial genes. Main Outcome Measure(s) RNA was analyzed by real-time RT-PCR and protein levels were assessed by ELISA. Result(s) The FTEC were demonstrated to express TLR1-9 but not 10. Treatment of FTEC with TLR3 agonist poly(I:C) resulted in increased expression of IL-8, TNF-α, human β-defensin 2, interferon beta, and interferon stimulated genes myxovirus resistance gene 1, 2′,5′-oligoadenylate synthetase, and protein kinase R. Additionally, FTEC exposed to poly(I:C) also resulted in the induction of TLR 2, 3, and 7. Conclusion(s) Our results suggest that FTEC are sensitive to viral infection and/or exposure to viral dsRNA and can respond by secreting proinflammatory cytokines that mediate the initiation of an inflammatory response as well as expressing genes that can directly inhibit viral replication. PMID:17669408

  8. Investigation of 1377C/T polymorphism of the Toll-like receptor 3 among patients with chronic hepatitis B.

    PubMed

    Goktas, Emine Firat; Bulut, Cemal; Goktas, Mustafa Tugrul; Ozer, Erdem Kamil; Karaca, Ragip Ozgur; Kinikli, Sami; Demiroz, Ali Pekcan; Bozkurt, Atilla

    2016-07-01

    The immunopathogenesis of chronic hepatitis B (CHB) has not been clarified yet. Toll-like receptors (TLR) are a receptor family that initiates immunity with exogenous-endogenous ligands and plays a role in the pathogenesis of infections. In this study, we aimed to investigate the frequency of TLR 3 1377C/T (rs3775290) polymorphism and its role in patients with CHB. We included 50 healthy individuals as control group and 73 active and 43 inactive hepatitis B patients. All DNA samples were isolated from blood samples. For the detection of TLR 3 1377C/T single-nucleotide polymorphism, restriction fragment length polymorphism was used. A statistically significant difference was determined in Hepatitis B virus (HBV) DNA levels of CHB patients with the CC, CT, and TT genotypes (p = 0.013). The highest levels of HBV DNA were detected in individuals with TT genotypes. Additionally, the frequency of CC genotype was higher in the active CHB patients compared with that of the inactive CHB patients (p = 0.044). No statistically significant difference in TLR 3 1377C/T polymorphism was detected between healthy controls and the hepatitis B patients (p = 0.342). In conclusion, HBV DNA level was higher in the individuals with TT genotype, and CC genotype was more frequent in the active CHB patients. These results suggest a possible association between CHB and TLR 3 gene (1377C/T) polymorphism.

  9. 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

  10. Combination of imipenem and TAK-242, a Toll-like receptor 4 signal transduction inhibitor, improves survival in a murine model of polymicrobial sepsis.

    PubMed

    Sha, Takuryu; Iizawa, Yuji; Ii, Masayuki

    2011-02-01

    Sepsis is characterized by an excessive host response to infection. Toll-like receptors (TLRs) are essential for triggering this type of host immune response. Toll-like receptor 4 mediates recognition of LPS from gram-negative bacteria and is an important initiator of sepsis. In the present study, we evaluated the efficacy of TAK-242, a novel TLR4 signal transduction inhibitor, in a murine cecal ligation and puncture (CLP) model. Treatment with TAK-242 (10 mg/kg i.v.) in combination with imipenem (1 mg/kg s.c.) 1 h after CLP significantly increased the survival rates of mice from 17% to 50% (P ≤ 0.01) and suppressed CLP-induced increases in serum levels of IL-1[beta], IL-6, IL-10, and macrophage inflammatory protein 2 by 64%, 73%, 79%, and 81%, respectively (P ≤ 0.025). Additionally, coadministration of TAK-242 with imipenem after CLP significantly inhibited CLP-induced decreases in blood platelet counts by 37% (P ≤ 0.025) and increases in serum levels of alanine aminotransferase by 32% (P ≤ 0.025) and blood urea nitrogen by 43% (P ≤ 0.025). TAK-242 at a dose of 10 mg/kg had no effect on bacterial counts in blood, suggesting that it does not affect blood bacteria spread. These results indicate that TAK-242 shows therapeutic effects in murine polymicrobial sepsis, and it may be a potential therapeutic agent for the treatment of sepsis. PMID:20720515

  11. Heme-Mediated Induction of CXCL10 and Depletion of CD34+ Progenitor Cells Is Toll-Like Receptor 4 Dependent.

    PubMed

    Dickinson-Copeland, Carmen M; Wilson, Nana O; Liu, Mingli; Driss, Adel; Salifu, Hassana; Adjei, Andrew A; Wilson, Michael; Gyan, Ben; Oduro, Daniel; Badu, Kingsley; Botchway, Felix; Anderson, Winston; Bond, Vincent; Bacanamwo, Methode; Singh, Shailesh; Stiles, Jonathan K

    2015-01-01

    Plasmodium falciparum infection can cause microvascular dysfunction, cerebral encephalopathy and death if untreated. We have previously shown that high concentrations of free heme, and C-X-C motif chemokine 10 (CXCL10) in sera of malaria patients induce apoptosis in microvascular endothelial and neuronal cells contributing to vascular dysfunction, blood-brain barrier (BBB) damage and mortality. Endothelial progenitor cells (EPC) are microvascular endothelial cell precursors partly responsible for repair and regeneration of damaged BBB endothelium. Studies have shown that EPC's are depleted in severe malaria patients, but the mechanisms mediating this phenomenon are unknown. Toll-like receptors recognize a wide variety of pathogen-associated molecular patterns generated by pathogens such as bacteria and parasites. We tested the hypothesis that EPC depletion during malaria pathogenesis is a function of heme-induced apoptosis mediated by CXCL10 induction and toll-like receptor (TLR) activation. Heme and CXCL10 concentrations in plasma obtained from malaria patients were elevated compared with non-malaria subjects. EPC numbers were significantly decreased in malaria patients (P < 0.02) and TLR4 expression was significantly elevated in vivo. These findings were confirmed in EPC precursors in vitro; where it was determined that heme-induced apoptosis and CXCL10 expression was TLR4-mediated. We conclude that increased serum heme mediates depletion of EPC during malaria pathogenesis.

  12. A toll-like receptor 3 single nucleotide polymorphism in Japanese patients with sarcoidosis.

    PubMed

    Ikezoe, K; Handa, T; Tanizawa, K; Kubo, T; Ito, I; Sokai, A; Nakatsuka, Y; Nagai, S; Izumi, T; Mishima, M

    2015-03-01

    Toll-like receptor 3 (TLR3) may be associated with T helper 1 immune response. This study aimed to investigate the role of a functional TLR3 single nucleotide polymorphism (SNP) in sarcoidosis. We genotyped 220 Japanese patients with sarcoidosis and 140 controls for TLR3 SNP rs3775291 to analyze its association with susceptibility to sarcoidosis and assessed its relationship to clinical features in 172 patients over 2 years. The TLR3 rs3775291 genotype was not significantly associated with disease susceptibility. However, patients with cardiac sarcoidosis (CS) significantly more frequently had the TT genotype (p < 0.01) or the T allele (p < 0.05) than those patients without CS. We conclude that TLR3 SNP rs3775291 may affect cardiac involvement in Japanese patients with sarcoidosis.

  13. Genomics in cardiovascular diseases: analysis of the importance of the toll-like receptor signaling pathway

    PubMed Central

    Bustamante, J; Tamayo, E; Herreros, J

    2012-01-01

    The development of techniques for genomics study makes it possible for us to further our knowledge about the physiopathology of various immunological or infectious diseases. These techniques improve our understanding of the development and evolution of such diseases, including those of cardiovascular origin, whilst they help to bring about the design of new therapeutic strategies. We are reviewing the genetic alterations of immunity in said field, and focusing on the signaling pathway of toll-like receptors because not only does this play a decisive role in response to microorganisms, it is also heavily involved in modulating the inflammatory response to tissue damage, a side effect of numerous cardiovascular diseases. These alterations in tissue homeostasis are present under a wide range of circumstances, such as reperfusion ischemia (myocardial infarction) phenomena, arteriosclerosis, or valvulopathy. PMID:23204853

  14. Toll-like receptors in alcoholic liver disease, non-alcoholic steatohepatitis and carcinogenesis.

    PubMed

    Roh, Yoon Seok; Seki, Ekihiro

    2013-08-01

    Activation of innate immune systems including Toll-like receptor (TLR) signaling is a key in chronic liver disease. Recent studies suggest that gut microflora-derived bacterial products (i.e. lipopolysaccharide [LPS], bacterial DNA) and endogenous substances (i.e. high-mobility group protein B1 [HMGB1], free fatty acids) released from damaged cells activate hepatic TLRs that contribute to the development of alcoholic (ASH) and non-alcoholic steatohepatitis (NASH) and liver fibrosis. The crucial role of TLR4, a receptor for LPS, has been implicated in the development of ASH, NASH, liver fibrosis, and hepatocellular carcinoma. However, the role of other TLRs, such as TLR2 and TLR9 in chronic liver disease remains less clear. In this review, we will discuss the role of TLR2, 4, and 9 in Kupffer cells and hepatic stellate cells in the development of ASH, NASH, and hepatocarcinogenesis. PMID:23855294

  15. The role of Toll-like receptors in retinal ischemic diseases

    PubMed Central

    Xu, Wen-Qin; Wang, Yu-Sheng

    2016-01-01

    Toll-like receptors (TLRs) are commonly referred to a series of evolutionary conserved receptors which recognize and respond to various microbes and endogenous ligands. Growing evidence has demonstrated that the expression of TLRs in the retina is regulated during retinal ischemic diseases, including ischemia-reperfusion injury, glaucoma, diabetic retinopathy (DR) and retinopathy of prematurity (ROP). TLRs can be expressed in multiple cells in the retina, such as glial cells, retinal pigment epithelium (RPE), as well as photoreceptor cells and endothelium cells. Activation of TLRs in retina could initiate a complex signal transduction cascade, induce the production of inflammatory cytokines and regulate the level of co-stimulatory molecules, which play prominent roles in the pathogenesis of retinal ischemic diseases. In this review, we summarized current studies about the relationship between TLRs and ischemic retinopathy. A greater understanding of the effect of TLRs on ischemic injuries may contribute to the development of specific TLR targeted therapeutic strategies in these conditions.

  16. 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

  17. Incorporation of Phosphonate into Benzonaphthyridine Toll-like Receptor 7 Agonists for Adsorption to Aluminum Hydroxide.

    PubMed

    Cortez, Alex; Li, Yongkai; Miller, Andrew T; Zhang, Xiaoyue; Yue, Kathy; Maginnis, Jillian; Hampton, Janice; Hall, De Shon; Shapiro, Michael; Nayak, Bishnu; D'Oro, Ugo; Li, Chun; Skibinski, David; Mbow, M Lamine; Singh, Manmohan; O'Hagan, Derek T; Cooke, Michael P; Valiante, Nicholas M; Wu, Tom Y-H

    2016-06-23

    Small molecule Toll-like receptor 7 (TLR7) agonists have been used as vaccine adjuvants by enhancing innate immune activation to afford better adaptive response. Localized TLR7 agonists without systemic exposure can afford good adjuvanticity, suggesting peripheral innate activation (non-antigen-specific) is not required for immune priming. To enhance colocalization of antigen and adjuvant, benzonaphthyridine (BZN) TLR7 agonists are chemically modified with phosphonates to allow adsorption onto aluminum hydroxide (alum), a formulation commonly used in vaccines for antigen stabilization and injection site deposition. The adsorption process is facilitated by enhancing aqueous solubility of BZN analogs to avoid physical mixture of two insoluble particulates. These BZN-phosphonates are highly adsorbed onto alum, which significantly reduced systemic exposure and increased local retention post injection. This report demonstrates a novel approach in vaccine adjuvant design using phosphonate modification to afford adsorption of small molecule immune potentiator (SMIP) onto alum, thereby enhancing co-delivery with antigen. PMID:27270029

  18. Toll-Like Receptor 11 (TLR11) Interacts with Flagellin and Profilin through Disparate Mechanisms.

    PubMed

    Hatai, Hirotsugu; Lepelley, Alice; Zeng, Wangyong; Hayden, Matthew S; Ghosh, Sankar

    2016-01-01

    Toll-like receptors (TLRs) are innate immune receptors that sense a variety of pathogen-associated molecular patterns (PAMPs) by interacting with them and subsequently initiating signal transduction cascades that elicit immune responses. TLR11 has been shown to interact with two known protein PAMPs: Salmonella and E. coli flagellin FliC and Toxoplasma gondii profilin-like protein. Given the highly divergent biology of these pathogens recognized by TLR11, it is unclear whether common mechanisms are used to recognize these distinct protein PAMPs. Here we show that TLR11 interacts with these two PAMPs using different receptor domains. Furthermore, TLR11 binding to flagellin and profilin exhibits differential dependency on pH and receptor ectodomain cleavage. PMID:26859749

  19. 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

  20. The role of Toll-like receptors in retinal ischemic diseases.

    PubMed

    Xu, Wen-Qin; Wang, Yu-Sheng

    2016-01-01

    Toll-like receptors (TLRs) are commonly referred to a series of evolutionary conserved receptors which recognize and respond to various microbes and endogenous ligands. Growing evidence has demonstrated that the expression of TLRs in the retina is regulated during retinal ischemic diseases, including ischemia-reperfusion injury, glaucoma, diabetic retinopathy (DR) and retinopathy of prematurity (ROP). TLRs can be expressed in multiple cells in the retina, such as glial cells, retinal pigment epithelium (RPE), as well as photoreceptor cells and endothelium cells. Activation of TLRs in retina could initiate a complex signal transduction cascade, induce the production of inflammatory cytokines and regulate the level of co-stimulatory molecules, which play prominent roles in the pathogenesis of retinal ischemic diseases. In this review, we summarized current studies about the relationship between TLRs and ischemic retinopathy. A greater understanding of the effect of TLRs on ischemic injuries may contribute to the development of specific TLR targeted therapeutic strategies in these conditions. PMID:27672603

  1. Adjuvants containing natural and synthetic Toll-like receptor 4 ligands.

    PubMed

    Ireton, Gregory C; Reed, Steven G

    2013-07-01

    The last decade has seen an increased focus on the development of adjuvants for vaccines, and several novel adjuvants are now in licensed products or in late-stage clinical development. These advancements have been aided by the discovery of receptors and signaling pathways of the innate immune system and an increased understanding of how these innate responses influence the adaptive immune response. Successful vaccine development relies on knowledge of which adjuvants to use and the proper formulation of adjuvants and antigens to achieve safe, stable and immunogenic vaccines. In this review, the authors focus on the current use of natural and synthetic lipopolysaccharide analogues that retain their adjuvant properties with reduced toxicity compared with the parent compound for use in emerging vaccines. The authors review how these compounds initiate signal transduction through Toll-like receptor 4, insights from structure-function studies and how formulation parameters can influence their effectiveness as vaccine adjuvants.

  2. Macroscopic law of conservation revealed in the population dynamics of Toll-like receptor signaling.

    PubMed

    Selvarajoo, Kumar

    2011-04-20

    Stimulating the receptors of a single cell generates stochastic intracellular signaling. The fluctuating response has been attributed to the low abundance of signaling molecules and the spatio-temporal effects of diffusion and crowding. At population level, however, cells are able to execute well-defined deterministic biological processes such as growth, division, differentiation and immune response. These data reflect biology as a system possessing microscopic and macroscopic dynamics. This commentary discusses the average population response of the Toll-like receptor (TLR) 3 and 4 signaling. Without requiring detailed experimental data, linear response equations together with the fundamental law of information conservation have been used to decipher novel network features such as unknown intermediates, processes and cross-talk mechanisms. For single cell response, however, such simplicity seems far from reality. Thus, as observed in any other complex systems, biology can be considered to possess order and disorder, inheriting a mixture of predictable population level and unpredictable single cell outcomes.

  3. IFN-alpha/beta-dependent cross-priming induced by specific toll-like receptor agonists.

    PubMed

    Durand, Vanessa; Wong, Simon Y C; Tough, David F; Le Bon, Agnes

    2006-04-12

    Toll-like receptors (TLR) are pattern recognition receptors that have been identified as crucial in the initiation of innate immune responses against pathogens. They are thought to be involved in shaping appropriate adaptive immune responses, although their precise contribution has not yet been fully characterised. Our aim was to investigate in vivo the effect of different TLR stimuli on cellular immune responses. We examined the ability of a range of TLR stimuli to induce CD8+ T cell responses against a model soluble protein antigen, ovalbumin (OVA). We found that TLR 3, TLR 4, and TLR 9 agonists induced functional cross-priming, and that this process was dependent on IFN-alpha/beta signalling pathway. PMID:16823911

  4. Human Toll like receptor 4 gene expression of PBMCs in diabetes mellitus type 2 patients.

    PubMed

    Sepehri, Z; Kiani, Z; Nasiri, A A; Mashhadi, M A; Javadian, F; Haghighi, A; Kohan, F; Bahari, A; Sargazi, A

    2015-07-31

    Toll like receptor 4 (TLR4) is one of the most pivotal pathogen recognition receptors (PRRs) in innate immune systems. In this study, we evaluate the expression of the TLR4 in patients with diabetes mellitus type 2 (DM2) in comparison to healthy controls. Expression of TLR4 in 32 human peripheral blood mononuclear cells (PBMCs) of patients with DM2 and 20 control samples was assessed using Real—Time PCR technique. For each patient, body mass index (BMI) and blood glucose levels were measured. The results of Real—Time PCR showed a 5—folds increase in expression of TLR4 on the PBMCs of DM2 patients in comparison to controls. No correlation was observed between the TLR4 expression and sex or BMI. Our results confirmed that DM2 can increase TLR4 expression independent from sex, blood glucose concentrations and BMI.

  5. Targeting Toll-like receptors: emerging therapeutics for multiple sclerosis management.

    PubMed

    Gambuzza, M; Licata, N; Palella, E; Celi, D; Foti Cuzzola, V; Italiano, D; Marino, S; Bramanti, P

    2011-10-28

    Toll-like receptors (TLR) are important innate immune proteins for the identification and clearance of invading pathogen. TLR signal through adaptor proteins, most commonly myeloid differentiation primary response gene 88 (MyD88). Inappropriate response of specific TLR has been implicated in certain autoimmune diseases, such as multiple sclerosis (MS). Activation of TLR2, TLR4, TLR7 and TLR9 plays a role in experimental allergic encephalomyelitis (EAE), a murine model of MS, while TLR3 activation protects from disease. Therefore, TLR-modulation could be an important adjuvant to current treatments. Here, we focus on TLR involved in EAE and MS pathogenesis highlighting specific components targeting TLR that might offer further therapeutic possibilities.

  6. Orphan receptor IL-17RD regulates Toll-like receptor signalling via SEFIR/TIR interactions.

    PubMed

    Mellett, Mark; Atzei, Paola; Bergin, Ronan; Horgan, Alan; Floss, Thomas; Wurst, Wolfgang; Callanan, John J; Moynagh, Paul N

    2015-01-01

    Receptor families of the innate immune response engage in 'cross-talk' to tailor optimal immune responses against invading pathogens. However, these responses are subject to multiple levels of regulation to keep in check aberrant inflammatory signals. Here, we describe a role for the orphan receptor interleukin-17 receptor D (IL-17RD) in negatively regulating Toll-like receptor (TLR)-induced responses. Deficiency of IL-17RD expression in cells leads to enhanced pro-inflammatory signalling and gene expression in response to TLR stimulation, and Il17rd(-/-) mice are more susceptible to TLR-induced septic shock. We demonstrate that the intracellular Sef/IL-17R (SEFIR) domain of IL-17RD targets TIR adaptor proteins to inhibit TLR downstream signalling thus revealing a paradigm involving cross-regulation of members of the IL-17R and TLR families.

  7. The role of Toll-like receptors in retinal ischemic diseases

    PubMed Central

    Xu, Wen-Qin; Wang, Yu-Sheng

    2016-01-01

    Toll-like receptors (TLRs) are commonly referred to a series of evolutionary conserved receptors which recognize and respond to various microbes and endogenous ligands. Growing evidence has demonstrated that the expression of TLRs in the retina is regulated during retinal ischemic diseases, including ischemia-reperfusion injury, glaucoma, diabetic retinopathy (DR) and retinopathy of prematurity (ROP). TLRs can be expressed in multiple cells in the retina, such as glial cells, retinal pigment epithelium (RPE), as well as photoreceptor cells and endothelium cells. Activation of TLRs in retina could initiate a complex signal transduction cascade, induce the production of inflammatory cytokines and regulate the level of co-stimulatory molecules, which play prominent roles in the pathogenesis of retinal ischemic diseases. In this review, we summarized current studies about the relationship between TLRs and ischemic retinopathy. A greater understanding of the effect of TLRs on ischemic injuries may contribute to the development of specific TLR targeted therapeutic strategies in these conditions. PMID:27672603

  8. The pharmacokinetics of Toll-like receptor agonists and the impact on the immune system.

    PubMed

    Engel, Abbi L; Holt, Gregory E; Lu, Hailing

    2011-03-01

    Toll-like receptor (TLR) ligation activates both the innate and adaptive immune systems, and plays an important role in antiviral and anti-tumor immunity. Therefore, a significant amount of effort has been devoted to exploit the therapeutic potential of TLR agonists. Depending on the therapeutic purpose, either as adjuvants to vaccine, chemotherapy or standalone therapy, TLR agonists have been administered via different routes. Both preclinical and clinical studies have suggested that the route of administration has significant effects on pharmacokinetics, and that understanding these effects is critical to the success of TLR agonist drug development. This article will summarize the pharmacokinetics of TLR agonists with different administration routes, with an emphasis on clinical studies of TLR ligands in oncologic applications. PMID:21643519

  9. The pharmacokinetics of Toll-like receptor agonists and the impact on the immune system

    PubMed Central

    Engel, Abbi L; Holt, Gregory E; Lu, Hailing

    2011-01-01

    Toll-like receptor (TLR) ligation activates both the innate and adaptive immune systems, and plays an important role in antiviral and anti-tumor immunity. Therefore, a significant amount of effort has been devoted to exploit the therapeutic potential of TLR agonists. Depending on the therapeutic purpose, either as adjuvants to vaccine, chemotherapy or standalone therapy, TLR agonists have been administered via different routes. Both preclinical and clinical studies have suggested that the route of administration has significant effects on pharmacokinetics, and that understanding these effects is critical to the success of TLR agonist drug development. This article will summarize the pharmacokinetics of TLR agonists with different administration routes, with an emphasis on clinical studies of TLR ligands in oncologic applications. PMID:21643519

  10. Role of inflammatory cells and toll-like receptors in atherosclerosis.

    PubMed

    Seneviratne, Anusha N; Monaco, Claudia

    2015-01-01

    The primary cause of cerebrovascular disease is atherosclerosis, to which many factors contribute. At first many saw atherosclerosis as a lipid-driven disease. Recently inflammation has appeared as a significant factor in the disease. Innate immune cells, for example monocytes and macrophages, are important in atherosclerosis. Toll-like receptors (TLRs) are the best-studied family of receptor in the immune system. TLR engagement with their ligands stimulates pro-inflammatory cytokine production and foam cell generation. Recently certain TLRs have shown a protective role in atherosclerosis. In this review, we analyse innate immunity, focusing on TLR signalling and macrophages, in atherosclerosis and acute cerebrovascular complications, and thereby discuss their potential as therapeutic targets.

  11. Cleavage and activation of a Toll-like receptor by microbial proteases

    PubMed Central

    de Zoete, Marcel R.; Bouwman, Lieneke I.; Keestra, A. Marijke; van Putten, Jos P. M.

    2011-01-01

    Toll-like receptors (TLRs) are innate receptors that show high conservation throughout the animal kingdom. Most TLRs can be clustered into phylogenetic groups that respond to similar types of ligands. One exception is avian TLR15. This receptor does not categorize into one of the existing groups of TLRs and its ligand is still unknown. Here we report that TLR15 is a sensor for secreted virulence-associated fungal and bacterial proteases. Activation of TLR15 involves proteolytic cleavage of the receptor ectodomain and stimulation of NF-κB–dependent gene transcription. Receptor activation can be mimicked by the expression of a truncated TLR15 of which the entire ectodomain is removed, suggesting that receptor cleavage alleviates receptor inhibition by the leucine-rich repeat domain. Our results indicate TLR15 as a unique type of innate immune receptor that combines TLR characteristics with an activation mechanism typical for the evolutionary distinct protease-activated receptors. PMID:21383168

  12. Cleavage and activation of a Toll-like receptor by microbial proteases.

    PubMed

    de Zoete, Marcel R; Bouwman, Lieneke I; Keestra, A Marijke; van Putten, Jos P M

    2011-03-22

    Toll-like receptors (TLRs) are innate receptors that show high conservation throughout the animal kingdom. Most TLRs can be clustered into phylogenetic groups that respond to similar types of ligands. One exception is avian TLR15. This receptor does not categorize into one of the existing groups of TLRs and its ligand is still unknown. Here we report that TLR15 is a sensor for secreted virulence-associated fungal and bacterial proteases. Activation of TLR15 involves proteolytic cleavage of the receptor ectodomain and stimulation of NF-κB-dependent gene transcription. Receptor activation can be mimicked by the expression of a truncated TLR15 of which the entire ectodomain is removed, suggesting that receptor cleavage alleviates receptor inhibition by the leucine-rich repeat domain. Our results indicate TLR15 as a unique type of innate immune receptor that combines TLR characteristics with an activation mechanism typical for the evolutionary distinct protease-activated receptors. PMID:21383168

  13. Toll-like receptor 2 ligands promote microglial cell death by inducing autophagy.

    PubMed

    Arroyo, Daniela S; Soria, Javier A; Gaviglio, Emilia A; Garcia-Keller, Constanza; Cancela, Liliana M; Rodriguez-Galan, Maria C; Wang, Ji Ming; Iribarren, Pablo

    2013-01-01

    Microglial cells are phagocytes in the central nervous system (CNS) and become activated in pathological conditions, resulting in microgliosis, manifested by increased cell numbers and inflammation in the affected regions. Thus, controlling microgliosis is important to prevent pathological damage to the brain. Here, we evaluated the contribution of Toll-like receptor 2 (TLR2) to microglial survival. We observed that activation of microglial cells with peptidoglycan (PGN) from Staphylococcus aureus and other TLR2 ligands results in cell activation followed by the induction of autophagy and autophagy-dependent cell death. In C57BL/6J mice, intracerebral injection of PGN increased the autophagy of microglial cells and reduced the microglial/macrophage cell number in brain parenchyma. Our results demonstrate a novel role of TLRs in the regulation of microglial cell activation and survival, which are important for the control of microgliosis and associated inflammatory responses in the CNS. PMID:23073832

  14. Mapping toll-like receptor signaling pathway genes of Zhikong scallop ( Chlamys farreri) with FISH

    NASA Astrophysics Data System (ADS)

    Zhao, Bosong; Zhao, Liang; Liao, Huan; Cheng, Jie; Lian, Shanshan; Li, Xuan; Huang, Xiaoting; Bao, Zhenmin

    2015-12-01

    Toll-like receptor (TLR) signaling pathway plays a pivotal role in the innate immune system. Studies on TLR signaling pathway genes in Zhikong scallop ( Chlamys farreri) have mainly focused on sequence analysis and expression profiling, no research has been carried out on their localization. The chromosomal position of TLR signaling pathway genes can be valuable for assemblying scallop genome and analysizing gene regulatory networks. In the present study, five key TLR signaling pathway genes ( CfTLR, CfMyd88, CfTRAF6, CfNFκB, and CfIκB) containing bacterial artificial chromosomes (BACs) were isolated and physically mapped through fluorescence in situ hybridization on five non-homologous chromosome pairs, showing a similar distribution to another five model species. The isolation and mapping of these key immune genes of C. farreri will aid to the research on innate immunity, assignment of interested genes to chromosomes, and integration of physical, linkage and cytogenetic maps of this species.

  15. Regulation of migration and invasion by Toll-like receptor-9 signaling network in prostate cancer

    PubMed Central

    Qiu, Jian-Ge; Zhang, Wen-Ji; Mei, Xiao-Long; Shi, Zhi; Di, Jin-Ming

    2015-01-01

    Toll-like receptors (TLRs) play an important role in tumorigenesis and progress of prostate cancer. However, the function and mechanism of Toll-like receptor-9 (TLR9) in prostate cancer is not totally understood. Here, we found that high expression of TLR9 was associated with a higher probability of lymph node metastasis and poor prognosis. Further in vitro functional study verified that silence of TLR9 inhibited migration and invasion of PC-3 cells, indicating expression of TLR9 involving in the migration and invasion of cancer cells. The data of microarray exhibited silence of TLR9 induced 205 genes with larger than 2-fold changes in expression levels, including 164 genes down-regulated and 41 genes up-regulated. Functional Gene Ontology (GO) processes annotation demonstrated that the top three scores of molecular and cellular functions were regulation of programmed cell death, regulation of locomotion and response to calcium ion. TLR9 signaling network analysis of the migration and invasion related genes identified several genes, like matrix metallopeptidase 2 (MMP2), matrix metallopeptidase 9 (MMP9), chemokine receptor 4 (CXCR4) and interleukin 8 (IL8), formed the core interaction network based on their known biological relationships. A few genes, such as odontogenic ameloblast-associated protein (ODAM), claudin 2 (CLDN2), gap junction protein beta 1 (GJB1) and Rho-associated coiled-coil containing protein kinase 1 pseudogene 1 (ROCK1P1), so far have not been found to interact with the other genes. This study provided the foundation to discover the new molecular mechanism in signaling networks of invasion and metastasis in prostate cancer. PMID:26087186

  16. Laquinimod prevents cuprizone-induced demyelination independent of Toll-like receptor signaling

    PubMed Central

    Menken, Lena; Hayardeny, Liat; Hanisch, Uwe-Karsten; Brück, Wolfgang

    2016-01-01

    Objective: To test whether Toll-like receptor (TLR) signaling plays a key role for reduced nuclear factor B (NF-κB) activation after laquinimod treatment in the model of cuprizone-induced demyelination, oligodendrocyte apoptosis, inflammation, and axonal damage. Methods: Ten-week-old C57BL/6J, TLR4−/−, and MyD88−/− mice received 0.25% cuprizone for 6 weeks and were treated daily with 25 mg/kg laquinimod or vehicle. After 6 weeks of demyelination, extent of demyelination, oligodendrocyte density, microglia infiltration, and axonal damage were analyzed in the corpus callosum. Additionally, we analyzed primary mouse astrocytes from C57BL/6J, TLR4−/−, MyD88−/−, and TRIF−/− mice for alteration in NF-κB signaling. Results: Vehicle-treated controls from C57BL/6J, TLR4−/−, and MyD88−/− mice displayed extensive callosal demyelination as well as microglial activation. In contrast, mice treated with 25 mg/kg laquinimod showed mainly intact callosal myelin. The demyelination score was significantly higher in all untreated mice compared to mice treated with laquinimod. There were significantly fewer APP-positive axonal spheroids, Mac3-positive macrophages/microglia, and less oligodendrocyte apoptosis in the corpus callosum of laquinimod-treated mice in comparison to untreated controls. Stimulated primary mouse astrocytes from laquinimod-treated groups show reduced NF-κB activation compared to vehicle-treated controls. Conclusions: Our results confirm that laquinimod prevents demyelination in the cuprizone mouse model for multiple sclerosis via downregulation of NF-κB activation. This laquinimod effect, however, does not involve upstream Toll-like receptor signaling. PMID:27231712

  17. Different selective pressures shape the evolution of Toll-like receptors in human and African great ape populations

    PubMed Central

    Quach, Hélène; Wilson, Daniel; Laval, Guillaume; Patin, Etienne; Manry, Jeremy; Guibert, Jessica; Barreiro, Luis B.; Nerrienet, Eric; Verschoor, Ernst; Gessain, Antoine; Przeworski, Molly; Quintana-Murci, Lluis

    2013-01-01

    The study of the genetic and selective landscape of immunity genes across primates can provide insight into the existing differences in susceptibility to infection observed between human and non-human primates. Here, we explored how selection has driven the evolution of a key family of innate immunity receptors, the Toll-like receptors (TLRs), in African great ape species. We sequenced the 10 TLRs in various populations of chimpanzees and gorillas, and analysed these data jointly with a human data set. We found that purifying selection has been more pervasive in great apes than in humans. Furthermore, in chimpanzees and gorillas, purifying selection has targeted TLRs irrespectively of whether they are endosomal or cell surface, in contrast to humans where strong selective constraints are restricted to endosomal TLRs. These observations suggest important differences in the relative importance of TLR-mediated pathogen sensing, such as that of recognition of flagellated bacteria by TLR5, between humans and great apes. Lastly, we used a population genetics-phylogenetics method that jointly analyses polymorphism and divergence data to detect fine-scale variation in selection pressures at specific codons within TLR genes. We identified different codons at different TLRs as being under positive selection in each species, highlighting that functional variation at these genes has conferred a selective advantage in immunity to infection to specific primate species. Overall, this study showed that the degree of selection driving the evolution of TLRs has largely differed between human and non-human primates, increasing our knowledge on their respective biological contribution to host defence in the natural setting. PMID:23851028

  18. Toll-like receptor 4 is not targeted to the lysosome in cystic fibrosis airway epithelial cells.

    PubMed

    Kelly, Catriona; Canning, Paul; Buchanan, Paul J; Williams, Mark T; Brown, Vanessa; Gruenert, Dieter C; Elborn, J Stuart; Ennis, Madeleine; Schock, Bettina C

    2013-03-01

    The innate immune response to bacterial infection is mediated through Toll-like receptors (TLRs), which trigger tightly regulated signaling cascades through transcription factors including NF-κB. LPS activation of TLR4 triggers internalization of the receptor-ligand complex which is directed toward lysosomal degradation or endocytic recycling. Cystic fibrosis (CF) patients display a robust and uncontrolled inflammatory response to bacterial infection, suggesting a defect in regulation. This study examined the intracellular trafficking of TLR4 in CF and non-CF airway epithelial cells following stimulation with LPS. We employed cells lines [16hBE14o-, CFBE41o- (CF), and CFTR-complemented CFBE41o-] and confirmed selected experiments in primary nasal epithelial cells from non-CF controls and CF patients (F508del homozygous). In control cells, TLR4 expression (surface and cytoplasmic) was reduced after LPS stimulation but remained unchanged in CF cells and was accompanied by a heightened inflammatory response 24 h after stimulation. All cells expressed markers of the early (EEA1) and late (Rab7b) endosomes at basal levels. However, only CF cells displayed persistent expression of Rab7b following LPS stimulation. Rab7 variants may directly internalize bacteria to the Golgi for recycling or to the lysosome for degradation. TLR4 colocalized with the lysosomal marker LAMP1 in 16 hBE14o- cells, suggesting that TLR4 is targeted for lysosomal degradation in these cells. However, this colocalization was not observed in CFBE41o- cells, where persistent expression of Rab7 and release of proinflammatory cytokines was detected. Consistent with the apparent inability of CF cells to target TLR4 toward the lysosome for degradation, we observed persistent surface and cytoplasmic expression of this pathogen recognition receptor. This defect may account for the prolonged cycle of chronic inflammation associated with CF. PMID:23316065

  19. Toll-Like Receptor 4-Linked Janus Kinase 2 Signaling Contributes to Internalization of Brucella abortus by Macrophages

    PubMed Central

    Lee, Jin Ju; Kim, Dong Hyeok; Kim, Dae Geun; Lee, Hu Jang; Min, Wongi; Rhee, Man Hee; Cho, Jae Youl; Watarai, Masahisa

    2013-01-01

    Brucella abortus is an intracellular pathogen that uses a crafty strategy to invade and proliferate within host cells, but the distinct signaling pathways associated with phagocytic mechanisms of B. abortus remain unclear. The present study was performed to test the hypothesis that Toll-like receptor 4 (TLR4)-linked signaling interacting with Janus kinase 2 (JAK2) plays an essential role in B. abortus phagocytosis by macrophages. The effects of TLR4-JAK2 signaling on B. abortus phagocytosis in murine macrophage RAW 264.7 cells were observed through an infection assay and confocal microscopy. We determined that the uptake of B. abortus was negatively affected by the dysfunction of TLR4 and JAK2. F-actin polymerization detected by flow cytometry and F-actin assay was amplified for B. abortus entry, whereas that event was attenuated by the disruption of TLR4 and JAK2. Importantly, JAK2 phosphorylation and actin skeleton reorganization were suppressed immediately after B. abortus infection in bone marrow-derived macrophages (BMDMs) from TLR4−/− mice, showing the cooperation of JAK2 with TLR4. Furthermore, small GTPase Cdc42 participated in the intermediate pathway of TLR4-JAK2 signaling on B. abortus phagocytosis. Consequently, TLR4-associated JAK2 activation in the early cellular signaling events plays a pivotal role in B. abortus-induced phagocytic processes in macrophages, implying the pathogenic significance of JAK2-mediated entry. Here, we elucidate that this specific phagocytic mechanism of B. abortus might provide achievable strategies for inhibiting B. abortus invasion. PMID:23630962

  20. Different patterns of Toll-like receptor 2 polymorphisms in populations of various ethnic and geographic origins.

    PubMed

    Ioana, M; Ferwerda, B; Plantinga, T S; Stappers, M; Oosting, M; McCall, M; Cimpoeru, A; Burada, F; Panduru, N; Sauerwein, R; Doumbo, O; van der Meer, J W M; van Crevel, R; Joosten, L A B; Netea, M G

    2012-05-01

    Upon the invasion of the host by microorganisms, innate immunity is triggered through pathogen recognition by pattern recognition receptors (PRRs). Toll-like receptors (TLRs) are the best-studied class of PRRs, and they recognize specific pathogen-associated molecular patterns (PAMPs) from various microorganisms. A large number of studies have shown that genetic variation in TLRs may influence susceptibility to infections. We assessed the genetic variation of TLR2, which encodes one of the most important TLRs, in various populations around the globe and correlated it with changes in the function of the molecule. The three best-known nonsynonymous TLR2 polymorphisms (1892C>A, 2029C>T, and 2258G>A) were assessed in different populations from the main continental masses: Romanians, Vlax-Roma, Dutch (European populations), Han Chinese (East Asia), Dogon, Fulani (Africa), and Trio Indians (America). The 2029C>T polymorphism was absent in both European and non-European populations, with the exception of the Vlax-Roma, suggesting that this polymorphism most likely arose in Indo-Aryan people after migration into South Asia. The 1892C>A polymorphism that was found exclusively in European populations, but not in Asian, African, or American volunteers, probably occurred in proto-Indo-Europeans. Interestingly, 2258G>A was present only in Europeans, including Vlax-Roma, but at a very low frequency. The differential pattern of the TLR2 polymorphisms in various populations may explain some of the differences in susceptibility to infections between these populations.

  1. Single nucleotide polymorphisms in toll-like receptor genes and case-control association studies with bovine tuberculosis

    PubMed Central

    Bhaladhare, Ashish; Sharma, Deepak; Kumar, Amit; Sonwane, Arvind; Chauhan, Anuj; Singh, Ranvir; Kumar, Pushpendra; Yadav, Ramji; Baqir, Mohd; Bhushan, Bharat; Prakash, Om

    2016-01-01

    Aim: Toll-like receptor 2 (TLR2) and TLR4 genes play critical roles in host recognition of Mycobacterium bovis infection and initiation of innate and adaptive immune response. The present study was aimed at exploring the association of seven single nucleotide polymorphisms (SNPs) in TLR2 and TLR4 genes with susceptibility/resistance against bovine tuberculosis (bTB) infection in cattle. Materials and Methods: A case-control resource population of 35 positive and 45 negative animals was developed after screening with single intradermal tuberculin test for bTB. Resource population was screened for SNPs in TLR2 and TLR4 genes using polymerase chain reaction-restriction fragment length polymorphism. The PROC LOGISTIC procedure of SAS 9.3 was used to find an association of allelic and genotypic frequencies with bTB. Results: In TLR2 gene, two of SNPs under study (rs55617172 and rs68268253) revealed polymorphism while in the case of TLR4 gene all four SNPs under investigation (rs8193041, rs207836014, rs8193060, and rs8193069) were found to be polymorphic in case-control population. SNP locus rs55617172 in TLR2 gene was found significantly (p<0.01) associated with susceptibility/resistance to TB in cattle. Conclusion: These findings indicate the presence of SNPs in TLR2 and TLR4 genes in our resource population. Upon validation in independent, large resource population and following biological characterization, SNP rs55617172 can be incorporated in marker panel for selection of animals with greater resistance to bTB. PMID:27284220

  2. Cloning, sequence analysis and expression profiles of Toll-like receptor 7 from Chinese giant salamander Andrias davidianus.

    PubMed

    Huang, Lili; Fan, Yuding; Zhou, Yong; Jiang, Nan; Liu, Wenzhi; Meng, Yan; Zeng, Lingbing

    2015-06-01

    The Chinese giant salamander, Andrias davidianus, is the largest extant amphibian species in the world, which is of significance due to its specific position in the evolutionary history of vertebrates. Currently, limited information about the innate immune system of this animal is known. In this study, the toll-like receptor 7 (TLR7), designated CgsTLR7, was cloned from Chinese giant salamander, A. davidianus. The full-length cDNA of CgsTLR7 is 3747 bp, with an open reading frame of 3150 bp, encoding 1049 amino acids. The TLR family motifs, including the leucine-rich repeat (LRR) and Toll/interleukin (IL)-1 receptor (TIR) domain are conserved in CgsTLR7, which includes 19 LRRs and a TIR domain. The predicted amino acid sequence of CgsTLR7 has 71%, 65%, 63% and 55% identity with turtle, chicken, human and fugu TLR7 homologues, respectively. Phylogenetic analysis showed that CgsTLR7 is closest to that of frog TLR7 among the examined species. Quantitative real-time PCR analysis revealed broad expression of CgsTLR7 in tissues from apparently healthy Chinese giant salamanders with the highest expression in the liver and the lowest expression in the intestine. The mRNA expression was up-regulated and reached a peak level in the kidney, liver and spleen at 12 h, 24 h and 48 h after infecting the animals with the giant salamander iridovirus (GSIV), respectively. These results suggest that CgsTLR7 has a conserved gene structure and might play an important role in immune regulation against viral infections in the Chinese giant salamander.

  3. Toll-like receptor 2-mediated modulation of growth and functions of regulatory T cells by oral streptococci.

    PubMed

    Saeki, A; Segawa, T; Abe, T; Sugiyama, M; Arimoto, T; Hara, H; Hasebe, A; Ohtani, M; Tanizume, N; Ohuchi, M; Kataoka, H; Kawanami, M; Yokoyama, A; Shibata, K

    2013-08-01

    This study was designed to determine whether oral streptococci modulate the growth and functions of regulatory T cells. Heat-killed cells of wild-type strains of Streptococcus gordonii and Streptococcus mutans induced the Toll-like receptor 2 (TLR2) -mediated nuclear factor-κB (NF-κB) activation, but their lipoprotein-deficient strains did not. Stimulation with these streptococci resulted in a significant increase in the frequency of CD4(+) CD25(+) Foxp3(+) regulatory T cells in splenocytes derived from both TLR2(+/+) and TLR2(-/-) mice, but the level of increase in TLR2(+/+) splenocytes was stronger than that in TLR2(-/-) splenocytes. Both strains of S. gordonii enhanced the proliferation of CD4(+) CD25(+) Foxp3(+) regulatory T cells isolated from TLR2(+/+) mice at the same level as those from TLR2(-/-) mice in an interleukin-2-independent manner. However, wild-type and lipoprotein-deficient strains of both streptococci did not enhance the suppressive activity of the isolated regulatory T cells in vitro, but rather inhibited it. TLR ligands also inhibited the suppressive activity of the regulatory T cells. Inhibition of the suppressive activity was recovered by the addition of anti-IL-6 antibody. Pretreatment of antigen-presenting cells with the NF-κB inhibitor BAY11-7082 enhanced the suppressive activity of the regulatory T cells. These results suggested that interleukin-6 produced by antigen-presenting cells inhibits the suppressive activity of the regulatory T cells. Wild-type strain, but not lipoprotein-deficient strain, of S. gordonii reduced the frequency of CD4(+)  CD25(+)  Foxp3(+) regulatory T cells in the acute infection model, whereas both strains of S. gordonii increased it in the chronic infection model mice. Hence, this study suggests that oral streptococci are capable of modulating the growth and functions of regulatory T cells in vitro and in vivo.

  4. Toll-Like Receptor 2 Stimulation of Osteoblasts Mediates Staphylococcus Aureus Induced Bone Resorption and Osteoclastogenesis through Enhanced RANKL

    PubMed Central

    Kassem, Ali; Lindholm, Catharina; Lerner, Ulf H

    2016-01-01

    Severe Staphylococcus aureus (S. aureus) infections pose an immense threat to population health and constitute a great burden for the health care worldwide. Inter alia, S. aureus septic arthritis is a disease with high mortality and morbidity caused by destruction of the infected joints and systemic bone loss, osteoporosis. Toll-Like receptors (TLRs) are innate immune cell receptors recognizing a variety of microbial molecules and structures. S. aureus recognition via TLR2 initiates a signaling cascade resulting in production of various cytokines, but the mechanisms by which S. aureus causes rapid and excessive bone loss are still unclear. We, therefore, investigated how S. aureus regulates periosteal/endosteal osteoclast formation and bone resorption. S. aureus stimulation of neonatal mouse parietal bone induced ex vivo bone resorption and osteoclastic gene expression. This effect was associated with increased mRNA and protein expression of receptor activator of NF-kB ligand (RANKL) without significant change in osteoprotegerin (OPG) expression. Bone resorption induced by S. aureus was abolished by OPG. S. aureus increased the expression of osteoclastogenic cytokines and prostaglandins in the parietal bones but the stimulatory effect of S. aureus on bone resorption and Tnfsf11 mRNA expression was independent of these cytokines and prostaglandins. Stimulation of isolated periosteal osteoblasts with S. aureus also resulted in increased expression of Tnfsf11 mRNA, an effect lost in osteoblasts from Tlr2 knockout mice. S. aureus stimulated osteoclastogenesis in isolated periosteal cells without affecting RANKL-stimulated resorption. In contrast, S. aureus inhibited RANKL-induced osteoclast formation in bone marrow macrophages. These data show that S. aureus enhances bone resorption and periosteal osteoclast formation by increasing osteoblast RANKL production through TLR2. Our study indicates the importance of using different in vitro approaches for studies of how S

  5. Stimulation of Toll-like receptor 2 in human platelets induces a thromboinflammatory response through activation of phosphoinositide 3-kinase.

    PubMed

    Blair, Price; Rex, Sybille; Vitseva, Olga; Beaulieu, Lea; Tanriverdi, Kahraman; Chakrabarti, Subrata; Hayashi, Chie; Genco, Caroline A; Iafrati, Mark; Freedman, Jane E

    2009-02-13

    Cells of the innate immune system use Toll-like receptors (TLRs) to initiate the proinflammatory response to microbial infection. Recent studies have shown acute infections are associated with a transient increase in the risk of vascular thrombotic events. Although platelets play a central role in acute thrombosis and accumulating evidence demonstrates their role in inflammation and innate immunity, investigations into the expression and functionality of platelet TLRs have been limited. In the present study, we demonstrate that human platelets express TLR2, TLR1, and TLR6. Incubation of isolated platelets with Pam(3)CSK4, a synthetic TLR2/TLR1 agonist, directly induced platelet aggregation and adhesion to collagen. These functional responses were inhibited in TLR2-deficient mice and, in human platelets, by pretreatment with TLR2-blocking antibody. Stimulation of platelet TLR2 also increased P-selectin surface expression, activation of integrin alpha(IIb)beta(3), generation of reactive oxygen species, and, in human whole blood, formation of platelet-neutrophil heterotypic aggregates. TLR2 stimulation also activated the phosphoinositide 3-kinase (PI3-K)/Akt signaling pathway in platelets, and inhibition of PI3-K significantly reduced Pam(3)CSK4-induced platelet responses. In vivo challenge with live Porphyromonas gingivalis, a Gram-negative pathogenic bacterium that uses TLR2 for innate immune signaling, also induced significant formation of platelet-neutrophil aggregates in wild-type but not TLR2-deficient mice. Together, these data provide the first demonstration that human platelets express functional TLR2 capable of recognizing bacterial components and activating the platelet thrombotic and/or inflammatory pathways. This work substantiates the role of platelets in the immune and inflammatory response and suggests a mechanism by which bacteria could directly activate platelets.

  6. Divergent impact of Toll-like receptor 2 deficiency on repair mechanisms in healthy muscle versus Duchenne muscular dystrophy.

    PubMed

    Mojumdar, Kamalika; Giordano, Christian; Lemaire, Christian; Liang, Feng; Divangahi, Maziar; Qureshi, Salman T; Petrof, Basil J

    2016-05-01

    Injury to skeletal muscle, whether acute or chronic, triggers macrophage-mediated innate immunity in a manner which can be either beneficial or harmful for subsequent repair. Endogenous ligands for Toll-like receptor 2 (TLR2) are released by damaged tissues and might play an important role in activating the innate immune system following muscle injury. To test this hypothesis, we compared macrophage behaviour and muscle repair mechanisms in mice lacking TLR2 under conditions of either acute (cardiotoxin-induced) or chronic (mdx mouse genetic model of Duchenne muscular dystrophy; DMD) muscle damage. In previously healthy muscle subjected to acute damage, TLR2 deficiency reduced macrophage numbers in the muscle post-injury but did not alter the expression pattern of the prototypical macrophage polarization markers iNOS and CD206. In addition, there was abnormal persistence of necrotic fibres and impaired regeneration in TLR2-/- muscles after acute injury. In contrast, TLR2 ablation in chronically diseased muscles of mdx mice not only resulted in significantly reduced macrophage numbers but additionally modified their phenotype by shifting from inflammatory (iNOS(pos) CD206(neg) ) to more anti-inflammatory (iNOS(neg) CD206(pos) ) characteristics. This decrease in macrophage-mediated inflammation was associated with ameliorated muscle histopathology and improved force-generating capacity of the dystrophic muscle. Our results suggest that the role of TLR2 in macrophage function and skeletal muscle repair depends greatly upon the muscle injury context, and raise the possibility that inhibition of TLR2 could serve as a useful therapeutic measure in DMD. PMID:26800321

  7. Diet-induced obesity mediates a proinflammatory response in pancreatic β cell via toll-like receptor 4

    PubMed Central

    Li, Juan; Chen, Shufen; Qiang, Juan; Wang, Xin; Chen, Lei

    2014-01-01

    Toll-like receptor 4 has an important role in inflammation and immunity. Whether TLR4 signaling contributes to the link between insulin resistance and islet β cell dysfunction is an unanswered question. Here, we show that in the face of the same high-fat continuous stimulation for 24 weeks, in TLR4–/– HF mice, the weight, fraction of the liver, epididymal fat pad fraction, as well as blood glucose and insulin levels were lower than in the WT HF group. In TLR4–/– HF mice, the O2 consumption, CO2 production and activities were higher than in the WT HF group. Glucose tolerance test, insulin tolerance test and insulin release test suggest that the impaired insulin secretion was significantly improved in TLR4–/– HF mice, compared with the WT HF group. In TLR4–/– HF mice, islet β cell ultrastructure was not damaged in the face of the same high-fat continuous stimulation, compared to that in the WT HF group. By detecting glucose-stimulated insulin secretion in the primary islet, insulin secretion of TLR4–/– HF mice was better than that of the WT HF group, and in the TLR4–/– HF group, at the mRNA level, islet interleukin 6 (IL-6), tumor necrosis factor α (TNF-α), and monocyte chemotactic protein 1 (MCP-1) were significantly lower than in the WT HF group. There was the islet macrophage infiltration in the WT HF group, but no significant macrophage infiltration in the TLR4–/– HF group. These data suggest that the damaged islet functions of the high fat diet-induced obesity mice may be linked to the TLR4 expression level, and the recruitment of macrophages into the islets. PMID:26155140

  8. Dysfunction in macrophage toll-like receptor signaling caused by an inborn error of cationic amino acid transport.

    PubMed

    Kurko, Johanna; Vähä-Mäkilä, Mari; Tringham, Maaria; Tanner, Laura; Paavanen-Huhtala, Sari; Saarinen, Maiju; Näntö-Salonen, Kirsti; Simell, Olli; Niinikoski, Harri; Mykkänen, Juha

    2015-10-01

    Amino acids, especially arginine, are vital for the well-being and activity of immune cells, and disruption of amino acid balance may weaken immunity and predispose to infectious and autoimmune diseases. We present here a model of an inborn aminoaciduria, lysinuric protein intolerance (LPI), in which a single mutation in y(+)LAT1 cationic amino acid transporter gene SLC7A7 leads to a multisystem disease characterized by immunological complications, life-threatening pulmonary alveolar proteinosis and nephropathy. Macrophages are suggested to play a central role in LPI in the development of these severe secondary symptoms. We thus studied the effect of the Finnish y(+)LAT1 mutation on monocyte-derived macrophages where toll-like receptors (TLRs) act as the key molecules in innate immune response against external pathogens. The function of LPI patient and control macrophage TLR signaling was examined by stimulating the TLR2/1, TLR4 and TLR9 pathways with their associated pathogen-associated molecular patterns. Downregulation in expression of TLR9, IRF7, IRF3 and IFNB1 and in secretion of IFN-α was detected, suggesting an impaired response to TLR9 stimulation. In addition, secretion of TNF-α, IL-12 and IL-1RA by TLR2/1 stimulation and IL-12 and IL-1RA by TLR4 stimulation was increased in the LPI patients. LPI macrophages secreted significantly less nitric oxide than control macrophages, whereas plasma concentrations of inflammatory chemokines CXCL8, CXCL9 and CXCL10 were elevated in the LPI patients. In conclusion, our results strengthen the relevance of macrophages in the pathogenesis of LPI and, furthermore, suggest that cationic amino acid transport plays an important role in the regulation of innate immune responses.

  9. S6K1 Negatively Regulates TAK1 Activity in the Toll-Like Receptor Signaling Pathway

    PubMed Central

    Kim, So Yong; Baik, Kyung-Hwa; Baek, Kwan-Hyuck; Chah, Kyong-Hwa; Kim, Kyung Ah; Moon, Gyuyoung; Jung, Eunyu; Kim, Seong-Tae; Shim, Jae-Hyuck; Greenblatt, Matthew B.; Chun, Eunyoung

    2014-01-01

    Transforming growth factor β (TGF-β)-activated kinase 1 (TAK1) is a key regulator in the signals transduced by proinflammatory cytokines and Toll-like receptors (TLRs). The regulatory mechanism of TAK1 in response to various tissue types and stimuli remains incompletely understood. Here, we show that ribosomal S6 kinase 1 (S6K1) negatively regulates TLR-mediated signals by inhibiting TAK1 activity. S6K1 overexpression causes a marked reduction in NF-κB and AP-1 activity induced by stimulation of TLR2 or TLR4. In contrast, S6K1−/− and S6K1 knockdown cells display enhanced production of inflammatory cytokines. Moreover, S6K1−/− mice exhibit decreased survival in response to challenge with lipopolysaccharide (LPS). We found that S6K1 inhibits TAK1 kinase activity by interfering with the interaction between TAK1 and TAB1, which is a key regulator protein for TAK1 catalytic function. Upon stimulation with TLR ligands, S6K1 deficiency causes a marked increase in TAK1 kinase activity that in turn induces a substantial enhancement of NF-κB-dependent gene expression, indicating that S6K1 is negatively involved in the TLR signaling pathway by the inhibition of TAK1 activity. Our findings contribute to understanding the molecular pathogenesis of the impaired immune responses seen in type 2 diabetes, where S6K1 plays a key role both in driving insulin resistance and modulating TLR signaling. PMID:24277938

  10. Divergent impact of Toll-like receptor 2 deficiency on repair mechanisms in healthy muscle versus Duchenne muscular dystrophy.

    PubMed

    Mojumdar, Kamalika; Giordano, Christian; Lemaire, Christian; Liang, Feng; Divangahi, Maziar; Qureshi, Salman T; Petrof, Basil J

    2016-05-01

    Injury to skeletal muscle, whether acute or chronic, triggers macrophage-mediated innate immunity in a manner which can be either beneficial or harmful for subsequent repair. Endogenous ligands for Toll-like receptor 2 (TLR2) are released by damaged tissues and might play an important role in activating the innate immune system following muscle injury. To test this hypothesis, we compared macrophage behaviour and muscle repair mechanisms in mice lacking TLR2 under conditions of either acute (cardiotoxin-induced) or chronic (mdx mouse genetic model of Duchenne muscular dystrophy; DMD) muscle damage. In previously healthy muscle subjected to acute damage, TLR2 deficiency reduced macrophage numbers in the muscle post-injury but did not alter the expression pattern of the prototypical macrophage polarization markers iNOS and CD206. In addition, there was abnormal persistence of necrotic fibres and impaired regeneration in TLR2-/- muscles after acute injury. In contrast, TLR2 ablation in chronically diseased muscles of mdx mice not only resulted in significantly reduced macrophage numbers but additionally modified their phenotype by shifting from inflammatory (iNOS(pos) CD206(neg) ) to more anti-inflammatory (iNOS(neg) CD206(pos) ) characteristics. This decrease in macrophage-mediated inflammation was associated with ameliorated muscle histopathology and improved force-generating capacity of the dystrophic muscle. Our results suggest that the role of TLR2 in macrophage function and skeletal muscle repair depends greatly upon the muscle injury context, and raise the possibility that inhibition of TLR2 could serve as a useful therapeutic measure in DMD.

  11. CCL-34, a synthetic toll-like receptor 4 activator, modulates differentiation and maturation of myeloid dendritic cells

    PubMed Central

    Fu, Shu-Ling; Lin, Chun-Cheng; Hsu, Ming-Ling; Liu, Sheng-Hung; Huang, Yu-Chuen; Chen, Yu-Jen

    2016-01-01

    CCL-34, a synthetic α-galactosylceramide analog, has been reported as an activator of toll-like receptor 4 (TLR4) in macrophages. TLR4 is highly expressed in dendritic cell (DC) and several TLR4 agonists are known to trigger DC maturation. We herein evaluated the effect of CCL-34 on DC maturation. Human CD14+ monocyte-derived immature DC were treated with CCL-34, its inactive structural analog CCL-44, or LPS to assess the DC maturation. CCL-34 induced DC maturation according to their characteristically dendrite-forming morphology, CD83 expression and IL-12p70 production. The allostimulatory activity of DC on proliferation of naive CD4+CD45+RA+ T cells and their secretion of interferon-γ was increased by CCL-34. Phagocytosis, an important function of immature DC, was reduced after CCL-34 treatment. All these effects related to DC maturation were evidently induced by positive control LPS but not by CCL-44 treatment. TLR4 neutralization impaired human DC maturation triggered by CCL-34. The induction of IL-12, a hallmark of DC maturation, by CCL-34 and LPS was only evident in TLR4-competent C3H/HeN, but not in TLR4-defective C3H/HeJ mice. CCL-34 could further elicit the antigen presentation capability in mice inoculated with doxorubicin-treated colorectal cancer cells. In summary, CCL-34 triggers DC maturation via a TLR4-dependent manner, which supports its potential application as an immunostimulator. PMID:26883191

  12. Toll-Like Receptor-1 and Receptor-2 and Beta-Defensin in Postcholecystectomy Bile Duct Injury

    PubMed Central

    Miranda-Díaz, Alejandra Guillermina; Hermosillo-Sandoval, José Manuel; Villanueva-Pérez, Martha Arisbeth; Román-Pintos, Luis Miguel; García-Iglesias, Trinidad; Rodríguez-Carrizalez, Adolfo Daniel; Cardona-Muñoz, Ernesto Germán

    2015-01-01

    Postcholecystectomy bile duct injuries (BDI) produce hepatic cholestasis and cause infection of the biliary tract. The biliary cells participate in secreting cytokines and in expression of immune response receptors. Toll-like receptors (TLRs) conduct signalling and activate the innate and adaptive inflammatory response. The objective was to determine the serum levels of TLR-2 and the expression of TLR-1 and TLR-2 and β-defensin in liver biopsies of postcholecystectomy BDI patients. A transverse, analytical study with 2 groups was done. One group included healthy volunteers (control group) and other included 25 postcholecystectomy BDI patients with complete biliary obstruction. Using the Enzyme-linked Immunosorbent Assay (ELISA) technique, serum levels of TLR-2 were determined, and with immunofluorescence the morphologic analysis of TLR-1 and TLR-2 and β-defensin in liver biopsies of postcholecystectomy BDI patients was performed. The average TLR-2 serum level in the control group was 0.0 pg/mL and in the BDI group, 0.023 ± 0.0045 pg/mL (P < 0.0001, bilateral Mann Whitney U). Immunofluorescence was used to determine the expression in liver biopsies, blood vessels, bile ducts, and hepatic parenchyma where 12 hepatic biopsies were positive for TLR-1 with average of 3213057.74 ± 1071019.25 μm2; and 7 biopsies were positive for β-defensin with an average of 730364.33 ± 210838.02 μm2; and 6 biopsies positive for TLR-2, obtaining an average of 3354364.24 ± 838591.06 μm2. In conclusion, TLR-1 and TLR-2 and β-defensin play an important role in the innate antimicrobial defense of the hepatobiliary system. PMID:25755667

  13. 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. PMID:27259833

  14. Preconditioning of Microglia by α-Synuclein Strongly Affects the Response Induced by Toll-like Receptor (TLR) Stimulation

    PubMed Central

    Gonzalez-Rey, Elena; Lachaud, Christian C.; Guilliams, Tim; Fernandez-Montesinos, Rafael; Benitez-Rondan, Alicia; Robledo, Gema; Hmadcha, Abdelkrim; Delgado, Mario; Dobson, Christopher M.; Pozo, David

    2013-01-01

    In recent years, it has become accepted that α-synuclein (αSyn) has a key role in the microglia-mediated neuroinflammation, which accompanies the development of Parkinson’s disease and other related disorders, such as Dementia with Lewy Bodies and Alzheimer’s disease. Nevertheless, the cellular and molecular mechanisms underlying its pathological actions, especially in the sporadic forms of the diseases, are not completely understood. Intriguingly, several epidemiological and animal model studies have revealed a link between certain microbial infections and the onset or progression of sporadic forms of these neurodegenerative disorders. In this work, we have characterized the effect of toll-like receptor (TLR) stimulation on primary murine microglial cultures and analysed the impact of priming cells with extracellular wild-type (Wt) αSyn on the subsequent TLR stimulation of cells with a set of TLR ligands. By assaying key interleukins and chemokines we report that specific stimuli, in particular Pam3Csk4 (Pam3) and single-stranded RNA40 (ssRNA), can differentially affect the TLR2/1- and TLR7-mediated responses of microglia when pre-conditioned with αSyn by augmenting IL-6, MCP-1/CCL2 or IP-10/CXCL10 secretion levels. Furthermore, we report a skewing of αSyn-primed microglia stimulated with ssRNA (TLR7) or Pam3 (TLR2/1) towards intermediate but at the same time differential, M1/M2 phenotypes. Finally, we show that the levels and intracellular location of activated caspase-3 protein change significantly in αSyn-primed microglia after stimulation with these particular TLR agonists. Overall, we report a remarkable impact of non-aggregated αSyn pre-sensitization of microglia on TLR-mediated immunity, a phenomenon that could contribute to triggering the onset of sporadic α-synuclein-related neuropathologies. PMID:24236103

  15. 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.

  16. Oestrous cycle-related changes in production of Toll-like receptors and prostaglandins in the canine endometrium.

    PubMed

    Silva, E; Henriques, S; Brito, S; Ferreira-Dias, G; Lopes-da-Costa, L; Mateus, L

    2012-12-01

    The objectives of this study were to evaluate the following events in the canine endometrium over the course of the oestrous cycle: (i) the transcriptional profiles of genes encoding the Toll-like receptors (TLR1-TLR7 and TLR9); (ii) the transcription and protein expression levels of TLR2 and TLR4; (iii) the gene transcription profile of prostaglandin synthesis enzymes (PTGS2, PGES and PGFS); (iv) the response pattern of PGF(2α) and PGE(2) following exposure of endometrial explants to LPS and LTA. TLR1-TLR7 and TLR9 genes were transcribed in the endometrium of bitches throughout the oestrous cycle, which indicates that TLR-mediated immune surveillance is an important component of the defence mechanisms within the uterus. Canine endometrial mRNA and protein expression of TLR2 and TLR4 was up-regulated at the late dioestrus and anoestrus and was the lowest in the follicular phase and early dioestrus. The decreased mRNA and protein levels observed at early dioestrus may favour implantation, but may also be linked to the high prevalence of pyometra at this stage of the oestrous cycle. After LPS and LTA stimulation, endometrial explants produced more PGF(2α) than PGE(2), which may be related to the early demise of the corpus luteum observed in vivo in canine pyometra cases. Overall, these results indicate that TLRs are involved in the activation of the inflammatory response associated with pyometra in the bitch. TLRs may therefore be therapeutic targets for the control of uterine bacterial infections in the bitch and potentially in other species. PMID:22959486

  17. Molecular cloning and expression of toll-like receptor 4 (tlr4) in the blunt snout bream (Megalobrama amblycephala).

    PubMed

    Lai, Ruifang; Liu, Han; Jakovlić, Ivan; Zhan, Fanbin; Wei, Jin; Yang, Pinhong; Wang, Weimin

    2016-06-01

    Toll-like receptors (TLRs) play a pivotal role in teleost innate immune system. In this study, Megalobrama amblycephala (ma) tlr4 gene was cloned, its putative polypeptide product characterized, and expression analysed. Matlr4 cDNA is 2862 bp long, with an open reading frame of 2364 bp encoding 787 amino acids. MaTlr4 is a typical TLR protein, including the extracellular part with nine leucine-rich repeat motifs, a transmembrane region and a cytoplasmic Toll/interleukin-1 receptor domain. MaTlr4 has the highest level of identity (94%) and similarity (97%) with the grass carp Tlr4.2 homolog. This was also corroborated by the phylogenetic analysis, which placed MaTlr4 in a cluster with other cyprinid homologs. Matlr4 mRNA was ubiquitously expressed in all examined tissues and during all sampled developmental stages. The observed peak in matlr4 mRNA expression during gastrula and somite stages is in good agreement with its proposed role in the development of the neural system. Temporal expression patterns of matlr4 and maMyD88 mRNAs and proteins were analyzed in liver, spleen, head kidney, trunk kidney and intestine after Aeromonas hydrophila infection. And mRNA expression varied between different time-points. Both MaTlr4 and MaMyD88 protein expressions at 12 hpi were significantly enhanced in head kidney and intestine. These results indicate that matlr4 is involved in the immune response in M. amblycephala, and that it is indeed a functional homologue of tlr4s described in other animal species. PMID:26802439

  18. miR210 modulates respiratory burst in Apostichopus japonicus coelomocytes via targeting Toll-like receptor.

    PubMed

    Li, Chenghua; Zhao, Mengru; Zhang, Chi; Zhang, Weiwei; Zhao, Xuelin; Duan, Xuemei; Xu, Wei

    2016-12-01

    Immune responses of species in Echinodermata remains mysterious due to the lack of efforts made in the study of host defense mechanism in these species. More researches start focusing on this ancient immune system with the recognition the economic values of several species in this phylum, especially sea cucumbers. Here, we reported a study in the innate immunity of a sea cucumber species (Apostichopus japonicus) in response to infection of Vibrio splendidus. A novel differential expressed miRNA (miR-210) from the diseased sea cucumber coelomocytes was identified in our study. This miRNA molecule modulates Toll-like receptor gene (AjToll) expression via binding 3'UTR region from 906 nt to 930 nt. Upon the challenge of V. splendidus, coelomocytes in A. japonicas demonstrated a upregulation of AjToll but a downregulation of miR-210. Transfection of miR-210 agomirs in coelomocytes significantly depressed the expression of AjToll in cells. As a result of AjToll expression inhibition by miR-210, the AjToll downstream molecules involved in reactive oxygen species (ROS) were also altered in vivo. This ROS pathway alternation was consistent with that caused by knockdown of AjToll through small inference RNA (siRNA). Taken together, the results of this study demonstrated a novel immune regulatory pathway via miRN-210 in A. japonica, which provides basic knowledge in exploring innate immunity of Echinodermata, and also can be reference in disease control in sea cucumber culture industry. PMID:27545641

  19. Toll-Like Receptor 4 Mediates the Response of Epithelial and Stromal Cells to Lipopolysaccharide in the Endometrium

    PubMed Central

    Sheldon, Iain Martin; Roberts, Mark H.

    2010-01-01

    Background Ascending infections of the female genital tract with bacteria causes pelvic inflammatory disease (PID), preterm labour and infertility. Lipopolysaccharide (LPS) is the main component of the cell wall of Gram-negative bacteria. Innate immunity relies on the detection of LPS by Toll-like receptor 4 (TLR4) on host cells. Binding of LPS to TLR4 on immune cells stimulates secretion of pro-inflammatory cytokines such as IL-6, chemokines such as CXCL1 and CCL20, and prostaglandin E2. The present study tested the hypothesis that TLR4 on endometrial epithelial and stromal cells is essential for the innate immune response to LPS in the female genital tract. Methodology/Principal Findings Wild type (WT) mice expressed TLR4 in the endometrium. Intrauterine infusion of purified LPS caused pelvic inflammatory disease, with accumulation of granulocytes throughout the endometrium of WT but not Tlr4−/− mice. Intra-peritoneal infusion of LPS did not cause PID in WT or Tlr4−/− mice, indicating the importance of TLR4 in the endometrium for the detection of LPS in the female genital tract. Stromal and epithelial cells isolated from the endometrium of WT but not Tlr4−/− mice, secreted IL-6, CXCL1, CCL20 and prostaglandin E2 in response to LPS, in a concentration and time dependent manner. Co-culture of combinations of stromal and epithelial cells from WT and Tlr4−/− mice provided little evidence of stromal-epithelial interactions in the response to LPS. Conclusions/Significance The innate immune response to LPS in the female genital tract is dependent on TLR4 on the epithelial and stromal cells of the endometrium. PMID:20877575

  20. Cloning and expression analysis of a Toll-like receptor 22 (tlr22) gene from turbot, Scophthalmus maximus.

    PubMed

    Hu, Guo-Bin; Zhang, Shou-Feng; Yang, Xi; Liu, Da-Hai; Liu, Qiu-Ming; Zhang, Shi-Cui

    2015-06-01

    Toll-like receptor 22 (TLR22) exists exclusively in aquatic animals and recognizes double stranded RNA (dsRNA). In the present study, a tlr22 gene and its 5'-flanking sequence were cloned from turbot, Scophthalmus maximus, its immune responsive expression was subsequently studied in vivo. The turbot (sm)tlr22 gene spans over 5.6 kb with a structure of 4 exon-3 intron and encodes 962 amino acids. The deduced protein shows the highest sequence identity (76.7%) to Japanese flounder Tlr22 and possesses a signal peptide sequence, a leucine-rich repeat (LRR) domain composed of 27 LRR motifs, a transmembrane region and a Toll/interleukin-1 receptor (TIR) domain. Phylogenetic analysis grouped it with other teleost Tlr22s. The interferon-stimulated response element (ISRE) and signal transducer and activator of transcription (STAT) binding site important for the basal transcriptional activity of TLR3 were predicted in the 5'-flanking sequence of smtlr22 gene. Quantitative real-time PCR (qPCR) analysis demonstrated the constitutive expression of smtlr22 mRNA in all examined tissues with higher levels in the head kidney, kidney and spleen. Further, smtlr22 expression was significantly up-regulated following challenge with polyinosinic: polycytidylic acid (poly I:C), lipopolysaccharide (LPS) or turbot reddish body iridovirus (TRBIV) in the gills, head kidney, spleen and muscle, with maximum increases ranging from 2.56 to 6.24 fold upon different immunostimulants and organs. These findings suggest a possible role of Smtlr22 in the immune responses to the infections of a broad range of pathogens that include DNA and RNA viruses and Gram-negative bacteria. PMID:25770871

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

    PubMed Central

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

    2011-01-01

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

  2. Inosine-mediated modulation of RNA sensing by Toll-like receptor 7 (TLR7) and TLR8.

    PubMed

    Sarvestani, Soroush T; Tate, Michelle D; Moffat, Jessica M; Jacobi, Ashley M; Behlke, Mark A; Miller, Alistair R; Beckham, Simone A; McCoy, Claire E; Chen, Weisan; Mintern, Justine D; O'Keeffe, Meredith; John, Matthias; Williams, Bryan R G; Gantier, Michael P

    2014-01-01

    RNA-specific adenosine deaminase (ADAR)-mediated adenosine-to-inosine (A-to-I) editing is a critical arm of the antiviral response. However, mechanistic insights into how A-to-I RNA editing affects viral infection are lacking. We posited that inosine incorporation into RNA facilitates sensing of nonself RNA by innate immune sensors and accordingly investigated the impact of inosine-modified RNA on Toll-like receptor 7 and 8 (TLR7/8) sensing. Inosine incorporation into synthetic single-stranded RNA (ssRNA) potentiated tumor necrosis factor alpha (TNF-α) or alpha interferon (IFN-α) production in human peripheral blood mononuclear cells (PBMCs) in a sequence-dependent manner, indicative of TLR7/8 recruitment. The effect of inosine incorporation on TLR7/8 sensing was restricted to immunostimulatory ssRNAs and was not seen with inosine-containing short double-stranded RNAs or with a deoxy-inosine-modified ssRNA. Inosine-mediated increase of self-secondary structure of an ssRNA resulted in potentiated IFN-α production in human PBMCs through TLR7 recruitment, as established through the use of a TLR7 antagonist and Tlr7-deficient cells. There was a correlation between hyperediting of influenza A viral ssRNA and its ability to stimulate TNF-α, independent of 5'-triphosphate residues, and involving Adar-1. Furthermore, A-to-I editing of viral ssRNA directly enhanced mouse Tlr7 sensing, when present in proportions reproducing biologically relevant levels of RNA editing. Thus, we demonstrate for the first time that inosine incorporation into immunostimulatory ssRNA can potentiate TLR7/8 activation. Our results suggest a novel function of A-to-I RNA editing, which is to facilitate TLR7/8 sensing of phagocytosed viral RNA. PMID:24227841

  3. Inosine-Mediated Modulation of RNA Sensing by Toll-Like Receptor 7 (TLR7) and TLR8

    PubMed Central

    Sarvestani, Soroush T.; Tate, Michelle D.; Moffat, Jessica M.; Jacobi, Ashley M.; Behlke, Mark A.; Miller, Alistair R.; Beckham, Simone A.; McCoy, Claire E.; Chen, Weisan; Mintern, Justine D.; O'Keeffe, Meredith; John, Matthias

    2014-01-01

    RNA-specific adenosine deaminase (ADAR)-mediated adenosine-to-inosine (A-to-I) editing is a critical arm of the antiviral response. However, mechanistic insights into how A-to-I RNA editing affects viral infection are lacking. We posited that inosine incorporation into RNA facilitates sensing of nonself RNA by innate immune sensors and accordingly investigated the impact of inosine-modified RNA on Toll-like receptor 7 and 8 (TLR7/8) sensing. Inosine incorporation into synthetic single-stranded RNA (ssRNA) potentiated tumor necrosis factor alpha (TNF-α) or alpha interferon (IFN-α) production in human peripheral blood mononuclear cells (PBMCs) in a sequence-dependent manner, indicative of TLR7/8 recruitment. The effect of inosine incorporation on TLR7/8 sensing was restricted to immunostimulatory ssRNAs and was not seen with inosine-containing short double-stranded RNAs or with a deoxy-inosine-modified ssRNA. Inosine-mediated increase of self-secondary structure of an ssRNA resulted in potentiated IFN-α production in human PBMCs through TLR7 recruitment, as established through the use of a TLR7 antagonist and Tlr7-deficient cells. There was a correlation between hyperediting of influenza A viral ssRNA and its ability to stimulate TNF-α, independent of 5′-triphosphate residues, and involving Adar-1. Furthermore, A-to-I editing of viral ssRNA directly enhanced mouse Tlr7 sensing, when present in proportions reproducing biologically relevant levels of RNA editing. Thus, we demonstrate for the first time that inosine incorporation into immunostimulatory ssRNA can potentiate TLR7/8 activation. Our results suggest a novel function of A-to-I RNA editing, which is to facilitate TLR7/8 sensing of phagocytosed viral RNA. PMID:24227841

  4. Dynamics of the avian inflammatory response to Salmonella following administration of the toll-like receptor 5 agonist flagellin

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Flagellin is a highly evolutionarily conserved bacterial component that is recognized by the innate immune system through toll-like receptor (TLR) 5. Previous work has shown that flagellin is a potent stimulator in vitro of phagocytic cell functions of chickens. The purpose of the present study wa...

  5. 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...

  6. FATTY ACIDS MODULATE TOLL-LIKE RECEPTOR 4 ACTIVATION THROUGH REGULATION OF RECEPTOR DIMERIZATION AND RECRUITMENT INTO LIPID RAFTS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The saturated fatty acids acylated on Lipid A of lipopolysaccharide (LPS) or bacterial lipoproteins play critical roles in ligand recognition and receptor activation for Toll-like Receptor 4 (TLR4) and TLR2. The results from our previous studies (J Biol Chem 2003, 2004) demonstrated that saturated ...

  7. Recognition of Corynebacterium pseudodiphtheriticum by Toll-like receptors and up-regulation of antimicrobial peptides in human corneal epithelial cells

    PubMed Central

    Roy, Sanhita; Marla, Sushma; Praneetha, DC

    2015-01-01

    Bacterial keratitis is a major cause of corneal ulcers in developing and industrialized nations. In this study, we examined the host innate immune responses to Corynebacterium pseudodiphtheriticum, often overlooked as commensal, in human corneal epithelial cells. The expressions of innate immune mediators were determined by quantitative PCR from corneal ulcers of patients and immortalized human corneal epithelial cells (HCEC). We have found an elevated expression of Toll like receptors (TLRs) along with IL-6 and IL-1β from both ulcers and epithelial cells infected with C. pseudodiphtheriticum. Activation of NF-κB and MAPK signaling pathways were also observed in HCEC in response to C. pseudodiphtheriticum. In addition, we found a significant increase in the expression of antimicrobial peptides S100A8, S100A9 and human β-defensin 1 from both corneal ulcers and HCEC. PMID:26125127

  8. 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

  9. Toll-Like Receptor 2 Activation by Chlamydia trachomatis Is Plasmid Dependent, and Plasmid-Responsive Chromosomal Loci Are Coordinately Regulated in Response to Glucose Limitation by C. trachomatis but Not by C. muridarum▿

    PubMed Central

    O'Connell, Catherine M.; AbdelRahman, Yasser M.; Green, Erin; Darville, Hillary K.; Saira, Kazima; Smith, Bennett; Darville, Toni; Scurlock, Amy M.; Meyer, Christopher R.; Belland, Robert J.

    2011-01-01

    We previously demonstrated that plasmid-deficient Chlamydia muridarum retains the ability to infect the murine genital tract but does not elicit oviduct pathology because it fails to activate Toll-like receptor 2 (TLR2). We derived a plasmid-cured derivative of the human genital isolate Chlamydia trachomatis D/UW-3/Cx, strain CTD153, which also fails to activate TLR2, indicating this virulence phenotype is associated with plasmid loss in both C. trachomatis and C. muridarum. As observed with plasmid-deficient C. muridarum, CTD153 displayed impaired accumulation of glycogen within inclusions. Transcriptional profiling of the plasmid-deficient strains by using custom microarrays identified a conserved group of chromosomal loci, the expression of which was similarly controlled in plasmid-deficient C. muridarum strains CM972 and CM3.1 and plasmid-deficient C. trachomatis CTD153. However, although expression of glycogen synthase, encoded by glgA, was greatly reduced in CTD153, it was unaltered in plasmid-deficient C. muridarum strains. Thus, additional plasmid-associated factors are required for glycogen accumulation by this chlamydial species. Furthermore, in C. trachomatis, glgA and other plasmid-responsive chromosomal loci (PRCLs) were transcriptionally responsive to glucose limitation, indicating that additional regulatory elements may be involved in the coordinated expression of these candidate virulence effectors. Glucose-limited C. trachomatis displayed reduced TLR2 stimulation in an in vitro assay. During human chlamydial infection, glucose limitation may decrease chlamydial virulence through its effects on plasmid-responsive chromosomal genes. PMID:21199910

  10. Toll-like receptor 2 activation by Chlamydia trachomatis is plasmid dependent, and plasmid-responsive chromosomal loci are coordinately regulated in response to glucose limitation by C. trachomatis but not by C. muridarum.

    PubMed

    O'Connell, Catherine M; AbdelRahman, Yasser M; Green, Erin; Darville, Hillary K; Saira, Kazima; Smith, Bennett; Darville, Toni; Scurlock, Amy M; Meyer, Christopher R; Belland, Robert J

    2011-03-01

    We previously demonstrated that plasmid-deficient Chlamydia muridarum retains the ability to infect the murine genital tract but does not elicit oviduct pathology because it fails to activate Toll-like receptor 2 (TLR2). We derived a plasmid-cured derivative of the human genital isolate Chlamydia trachomatis D/UW-3/Cx, strain CTD153, which also fails to activate TLR2, indicating this virulence phenotype is associated with plasmid loss in both C. trachomatis and C. muridarum. As observed with plasmid-deficient C. muridarum, CTD153 displayed impaired accumulation of glycogen within inclusions. Transcriptional profiling of the plasmid-deficient strains by using custom microarrays identified a conserved group of chromosomal loci, the expression of which was similarly controlled in plasmid-deficient C. muridarum strains CM972 and CM3.1 and plasmid-deficient C. trachomatis CTD153. However, although expression of glycogen synthase, encoded by glgA, was greatly reduced in CTD153, it was unaltered in plasmid-deficient C. muridarum strains. Thus, additional plasmid-associated factors are required for glycogen accumulation by this chlamydial species. Furthermore, in C. trachomatis, glgA and other plasmid-responsive chromosomal loci (PRCLs) were transcriptionally responsive to glucose limitation, indicating that additional regulatory elements may be involved in the coordinated expression of these candidate virulence effectors. Glucose-limited C. trachomatis displayed reduced TLR2 stimulation in an in vitro assay. During human chlamydial infection, glucose limitation may decrease chlamydial virulence through its effects on plasmid-responsive chromosomal genes. PMID:21199910

  11. Toll-like receptor 4 knockout ameliorates neuroinflammation due to lung-brain interaction in mechanically ventilated mice.

    PubMed

    Chen, Ting; Chen, Chang; Zhang, Zongze; Zou, Yufeng; Peng, Mian; Wang, Yanlin

    2016-08-01

    Toll-like receptor 4 (TLR4) is a crucial receptor in the innate immune system, and increasing evidence supports its role in inflammation, stress, and tissue injury, including injury to the lung and brain. We aimed to investigate the effects of TLR4 on neuroinflammation due to the lung-brain interaction in mechanically ventilated mice. Male wild-type (WT) C57BL/6 and TLR4 knockout (TLR4 KO) mice were divided into three groups: (1) control group (C): spontaneous breathing; (2) anesthesia group (A): spontaneous breathing under anesthesia; and (3) mechanical ventilation group (MV): 6h of MV under anesthesia. The behavioral responses of mice were tested with fear conditioning tests. The histological changes in the lung and brain were assessed using hematoxylin-eosin (HE) staining. The level of TLR4 mRNA in tissue was measured using reverse transcription-polymerase chain reaction (RT-PCR). The levels of inflammatory cytokines were measured with an enzyme-linked immunosorbent assay (ELISA). Microgliosis, astrocytosis, and the TLR4 immunoreactivity in the hippocampus were measured by double immunofluorescence. MV mice exhibited impaired cognition, and this impairment was less severe in TLR4 KO mice than in WT mice. In WT mice, MV increased TLR4 mRNA expression in the lung and brain. MV induced mild lung injury, which was prevented in TLR4 KO mice. MV mice exhibited increased levels of inflammatory cytokines, increased microglia and astrocyte activation. Microgliosis was alleviated in TLR4 KO mice. MV mice exhibited increased TLR4 immunoreactivity, which was expressed in microglia and astrocytes. These results demonstrate that TLR4 is involved in neuroinflammation due to the lung-brain interaction and that TLR4 KO ameliorates neuroinflammation due to lung-brain interaction after prolonged MV. In addition, Administration of a TLR4 antagonist (100μg/mice) to WT mice also significantly attenuated neuroinflammation of lung-brain interaction due to prolonged MV. TLR4 antagonism

  12. Toll-Like Receptor 4 Wild Type Homozygozity of Polymorphisms +896 and +1196 Is Associated with High Gastrin Serum Levels and Peptic Ulcer Risk

    PubMed Central

    Pohjanen, Vesa-Matti; Koivurova, Olli-Pekka; Huhta, Heikki; Helminen, Olli; Mäkinen, Johanna M.; Karhukorpi, Jari M.; Joensuu, Tapio; Koistinen, Pentti O.; Valtonen, Jarno M.; Niemelä, Seppo E.; Karttunen, Riitta A.; Karttunen, Tuomo J.

    2015-01-01

    Toll-like receptor 4 is a part of the innate immune system and recognizes Helicobacter pylori lipopolysaccharide. The goal of this study was to analyze the role of Toll-like receptor 4 polymorphisms +896 (rs4986790) and +1196 (rs4986791) in the pathogenesis of Helicobacter pylori related gastroduodenal diseases in relation to gastric secretion and inflammation. Toll-like receptor 4 polymorphisms, serum gastrin-17 and pepsinogen I and II concentrations were determined, and gastroscopies with histopathological analyses were performed to 216 dyspeptic patients. As genotype controls, 179 controls and 61 gastric cancer patients were studied. In our study, the Toll-like receptor 4 +896 and +1196 polymorphisms were in total linkage disequilibrium. The homozygous wild types displayed higher gastrin-17 serum concentrations than the mutants (p = 0.001) and this effect was independent of Helicobacter pylori. The homozygous wild types also displayed an increased risk for peptic ulcers (OR: 4.390). Toll-like receptor 4 genotypes did not show any association with Helicobacter pylori positivity or the features of gastric inflammation. Toll-like receptor 4 expression was seen in gastrin and somatostatin expressing cells of antral mucosa by immunohistochemistry. Our results suggest a role for Toll-like receptor 4 in gastric acid regulation and that the Toll-like receptor 4 +896 and +1196 wild type homozygozity increases peptic ulcer risk via gastrin secretion. PMID:26161647

  13. A Novel Toll-Like Receptor (TLR) Influences Compatibility between the Gastropod Biomphalaria glabrata, and the Digenean Trematode Schistosoma mansoni.

    PubMed

    Pila, Emmanuel A; Tarrabain, Mahmoud; Kabore, Alethe L; Hanington, Patrick C

    2016-03-01

    Schistosomiasis, a devastating disease caused by parasitic flatworms of the genus Schistosoma, affects over 260 million people worldwide especially in tropical and sub-tropical regions. Schistosomes must undergo their larval development within specific species of snail intermediate hosts, a trait that is shared among almost all digenean trematodes. This unique and long-standing host-parasite relationship presents an opportunity to study both the importance of conserved immunological features in novel immunological roles, as well as new immunological adaptations that have arisen to combat a very specific type of immunological challenge. While it is well supported that the snail immune response is important for protecting against schistosome infection, very few specific snail immune factors have been identified and even fewer have been functionally characterized. Here, we provide the first functional report of a snail Toll-like receptor, which we demonstrate as playing an important role in the cellular immune response of the snail Biomphalaria glabrata following challenge with Schistosoma mansoni. This TLR (BgTLR) was identified as part of a peptide screen of snail immune cell surface proteins that differed in abundance between B. glabrata snails that differ in their compatibility phenotype to challenge by S. mansoni. The S. mansoni-resistant strain of B. glabrata (BS-90) displayed higher levels of BgTLR compared to the susceptible (M-line) strain. Transcript expression of BgTLR was found to be very responsive in BS-90 snails when challenged with S. mansoni, increasing 27 fold relative to β-actin (non-immune control gene); whereas expression in susceptible M-line snails was not significantly increased. Knockdown of BgTLR in BS-90 snails via targeted siRNA oligonucleotides was confirmed using a specific anti-BgTLR antibody and resulted in a significant alteration of the resistant phenotype, yielding patent infections in 43% of the normally resistant snails, which

  14. A Novel Toll-Like Receptor (TLR) Influences Compatibility between the Gastropod Biomphalaria glabrata, and the Digenean Trematode Schistosoma mansoni

    PubMed Central

    Pila, Emmanuel A.; Tarrabain, Mahmoud; Kabore, Alethe L.; Hanington, Patrick C.

    2016-01-01

    Schistosomiasis, a devastating disease caused by parasitic flatworms of the genus Schistosoma, affects over 260 million people worldwide especially in tropical and sub-tropical regions. Schistosomes must undergo their larval development within specific species of snail intermediate hosts, a trait that is shared among almost all digenean trematodes. This unique and long-standing host-parasite relationship presents an opportunity to study both the importance of conserved immunological features in novel immunological roles, as well as new immunological adaptations that have arisen to combat a very specific type of immunological challenge. While it is well supported that the snail immune response is important for protecting against schistosome infection, very few specific snail immune factors have been identified and even fewer have been functionally characterized. Here, we provide the first functional report of a snail Toll-like receptor, which we demonstrate as playing an important role in the cellular immune response of the snail Biomphalaria glabrata following challenge with Schistosoma mansoni. This TLR (BgTLR) was identified as part of a peptide screen of snail immune cell surface proteins that differed in abundance between B. glabrata snails that differ in their compatibility phenotype to challenge by S. mansoni. The S. mansoni-resistant strain of B. glabrata (BS-90) displayed higher levels of BgTLR compared to the susceptible (M-line) strain. Transcript expression of BgTLR was found to be very responsive in BS-90 snails when challenged with S. mansoni, increasing 27 fold relative to β-actin (non-immune control gene); whereas expression in susceptible M-line snails was not significantly increased. Knockdown of BgTLR in BS-90 snails via targeted siRNA oligonucleotides was confirmed using a specific anti-BgTLR antibody and resulted in a significant alteration of the resistant phenotype, yielding patent infections in 43% of the normally resistant snails, which

  15. Toll-like receptor and tumour necrosis factor dependent endotoxin-induced acute lung injury

    PubMed Central

    Togbe, Dieudonnée; Schnyder-Candrian, Silvia; Schnyder, Bruno; Doz, Emilie; Noulin, Nicolas; Janot, Laure; Secher, Thomas; Gasse, Pamela; Lima, Carla; Coelho, Fernando Rodrigues; Vasseur, Virginie; Erard, François; Ryffel, Bernhard; Couillin, Isabelle; Moser, Rene

    2007-01-01

    Recent studies on endotoxin/lipopolysaccharide (LPS)-induced acute inflammatory response in the lung are reviewed. The acute airway inflammatory response to inhaled endotoxin is mediated through Toll-like receptor 4 (TLR4) and CD14 signalling as mice deficient for TLR4 or CD14 are unresponsive to endotoxin. Acute bronchoconstriction, tumour necrosis factor (TNF), interleukin (IL)-12 and keratinocyte-derived chemokine (KC) production, protein leak and neutrophil recruitment in the lung are abrogated in mice deficient for the adaptor molecules myeloid differentiation factor 88 (MyD88) and Toll/Interleukin-1 receptor (TIR)-domain-containing adaptor protein (TIRAP), but independent of TIR-domain-containing adaptor-inducing interferon-beta (TRIF). In particular, LPS-induced TNF is required for bronchoconstriction, but dispensable for inflammatory cell recruitment. Lipopolysaccharide induces activation of the p38 mitogen-activated protein kinase (MAPK). Inhibition of pulmonary MAPK activity abrogates LPS-induced TNF production, bronchoconstriction, neutrophil recruitment into the lungs and broncho-alveolar space. In conclusion, TLR4-mediated, bronchoconstriction and acute inflammatory lung pathology to inhaled endotoxin are dependent on TLR4/CD14/MD2 expression using the adapter proteins TIRAP and MyD88, while TRIF, IL-1R1 or IL-18R signalling pathways are dispensable. Further downstream in this axis of signalling, TNF blockade reduces only acute bronchoconstriction, while MAPK inhibition abrogates completely endotoxin-induced inflammation. PMID:18039275

  16. Podocyte apoptosis is prevented by blocking the Toll-like receptor pathway

    PubMed Central

    Saurus, P; Kuusela, S; Lehtonen, E; Hyvönen, M E; Ristola, M; Fogarty, C L; Tienari, J; Lassenius, M I; Forsblom, C; Lehto, M; Saleem, M A; Groop, P-H; Holthöfer, H; Lehtonen, S

    2015-01-01

    High serum lipopolysaccharide (LPS) activity in normoalbuminuric patients with type 1 diabetes (T1D) predicts the progression of diabetic nephropathy (DN), but the mechanisms behind this remain unclear. We observed that treatment of cultured human podocytes with sera from normoalbuminuric T1D patients with high LPS activity downregulated 3-phosphoinositide-dependent kinase-1 (PDK1), an activator of the Akt cell survival pathway, and induced apoptosis. Knockdown of PDK1 in cultured human podocytes inhibited antiapoptotic Akt pathway, stimulated proapoptotic p38 MAPK pathway, and increased apoptosis demonstrating an antiapoptotic role for PDK1 in podocytes. Interestingly, PDK1 was downregulated in the glomeruli of diabetic rats and patients with type 2 diabetes before the onset of proteinuria, further suggesting that reduced expression of PDK1 associates with podocyte injury and development of DN. Treatment of podocytes in vitro and mice in vivo with LPS reduced PDK1 expression and induced apoptosis, which were prevented by inhibiting the Toll-like receptor (TLR) signaling pathway with the immunomodulatory agent GIT27. Our data show that LPS downregulates the cell survival factor PDK1 and induces podocyte apoptosis, and that blocking the TLR pathway with GIT27 may provide a non-nephrotoxic means to prevent the progression of DN. PMID:25950482

  17. Kidney Expression of Toll Like Receptors in Lupus Nephritis: Quantification and Clinicopathological Correlations.

    PubMed

    Conti, Fabrizio; Spinelli, Francesca Romana; Truglia, Simona; Miranda, Francesca; Alessandri, Cristiano; Ceccarelli, Fulvia; Bombardieri, Michele; Giannakakis, Konstantinos; Valesini, Guido

    2016-01-01

    Objective. The study aimed at locating and quantifying Toll Like Receptor (TLR) 3, 7, 8, and 9 expression in kidney of patients with lupus nephritis (LN) and correlating them with clinicopathological features. Methods. Kidney sections from 26 LN patients and 4 controls were analyzed by immunohistochemistry using anti-human TLR3, TLR7, TLR8, and TLR9 polyclonal antibodies; the number of TLR-positive nuclei/mm(2) was evaluated on digitalized images. Results. Compared to controls, LN showed a significantly higher amount of glomerular and tubulointerstitial TLR9 (p = 0.003 and p = 0.007), whole and tubulointerstitial TLR3 (p = 0.026 and p = 0.031), and a higher tubulointerstitial TLR7 (p = 0.022). TLR9 positively correlated with activity index (p = 0.0063) and tubular TLR7 with chronicity index (p = 0.026). TLR9 positively correlated with Renal-SLEDAI (p = 0.01). Conclusions. This is the first study quantifying kidney expressions of TLRs in LN patients; the results show an overexpression of TLR3, TLR7, and TLR9 and demonstrate a correlation with clinicopathological indices supporting a role of these mediators in the pathogenesis of LN. PMID:27635115

  18. Toll-like receptors gene polymorphisms may confer increased susceptibility to breast cancer development.

    PubMed

    Theodoropoulos, George E; Saridakis, Vasilios; Karantanos, Theodoros; Michalopoulos, Nikolaos V; Zagouri, Flora; Kontogianni, Panagiota; Lymperi, Maria; Gazouli, Maria; Zografos, George C

    2012-08-01

    Toll-like receptor (TLR) activation may be an important event in tumor cell immune evasion. TLR2 and TLR4 gene polymorphisms have been related to increased susceptibility to cancer development in various organs. 261 patients and 480 health individuals were investigated for genotype and allelic frequencies of a 22-bp nucleotide deletion (-196 to -174del) in the promoter of TLR2 gene as well as two polymorphisms causing amino acid substitutions (Asp299Gly and Thr399Ile) in TLR4 gene. As far as (-196 to -174del) in TLR2 gene is concerned ins/del and del/del genotypes and del allele were significantly more frequent in breast cancer patients compared to healthy controls. Considering Asp299Gly replacement of TLR4 gene, Gly carriers (Asp/Gly & Gly/Gly genotype) and Gly allele were overrepresented among the breast cancer cases. The -174 to -196del of TLR2 gene and Asp299Gly of TLR4 gene polymorphisms may confer an increased susceptibility to breast cancer development.

  19. Toll-Like Receptor 4 Reduces Oxidative Injury via Glutathione Activity in Sheep

    PubMed Central

    Deng, Shoulong; Yu, Kun; Wu, Qian; Li, Yan; Zhang, Xiaosheng; Zhang, Baolu; Liu, Guoshi; Liu, Yixun; Lian, Zhengxing

    2016-01-01

    Toll-like receptor 4 (TLR4) is an important sensor of Gram-negative bacteria and can trigger activation of the innate immune system. Increased activation of TLR4 can lead to the induction of oxidative stress. Herein, the pathway whereby TLR4 affects antioxidant activity was studied. In TLR4-overexpressing sheep, TLR4 expression was found to be related to the integration copy number when monocytes were challenged with lipopolysaccharide (LPS). Consequently, production of malondialdehyde (MDA) was increased, which could increase the activation of prooxidative stress enzymes. Meanwhile, activation of an antioxidative enzyme, glutathione peroxidase (GSH-Px), was increased. Real-time PCR showed that expression of activating protein-1 (AP-1) and the antioxidative-related genes was increased. By contrast, the expression levels of superoxide dismutase 1 (SOD1) and catalase (CAT) were reduced. In transgenic sheep, glutathione (GSH) levels were dramatically reduced. Furthermore, transgenic sheep were intradermally injected with LPS in each ear. The amounts of inflammatory infiltrates were correlated with the number of TLR4 copies that were integrated in the genome. Additionally, the translation of γ-glutamylcysteine synthetase (γ-GCS) was increased. Our findings indicated that overexpression of TLR4 in sheep could ameliorate oxidative injury through GSH secretion that was induced by LPS stimulation. Furthermore, TLR4 promoted γ-GCS translation through the AP-1 pathway, which was essential for GSH synthesis. PMID:26640618

  20. Structure-Activity Relationships in Toll-like Receptor-2 agonistic Diacylthioglycerol Lipopeptides

    PubMed Central

    Wu, Wenyan; Li, Rongti; Malladi, Subbalakshmi S.; Warshakoon, Hemamali J.; Kimbrell, Matthew R.; Amolins, Michael W.; Ukani, Rehman; Datta, Apurba; David, Sunil A.

    2010-01-01

    The N-termini of bacterial lipoproteins are acylated with a (S)-(2,3-bisacyloxypropyl)cysteinyl residue. Lipopeptides derived from lipoproteins activate innate immune responses by engaging Toll-like receptor 2 (TLR2), and are highly immunostimulatory and yet without apparent toxicity in animal models. The lipopeptides may therefore be useful as potential immunotherapeutic agents. Previous structure-activity relationships in such lipopeptides have largely been obtained using murine cells and it is now clear that significant species-specific differences exist between human and murine TLR responses. We have examined in detail the role of the highly conserved Cys residue as well as the geometry and stereochemistry of the Cys-Ser dipeptide unit. (R)-diacylthioglycerol analogues are maximally active in reporter gene assays using human TLR2. The Cys-Ser dipeptide unit represents the minimal part-structure, but its stereochemistry was found not to be a critical determinant of activity. The thioether bridge between the diacyl and dipeptide units is crucial, and replacement by an oxoether bridge results in a dramatic decrease in activity. PMID:20302301

  1. Toll-like Receptor 9 Can be Activated by Endogenous Mitochondrial DNA to Induce Podocyte Apoptosis

    PubMed Central

    Bao, Wenduona; Xia, Hong; Liang, Yaojun; Ye, Yuting; Lu, Yuqiu; Xu, Xiaodong; Duan, Aiping; He, Jing; Chen, Zhaohong; Wu, Yan; Wang, Xia; Zheng, Chunxia; Liu, Zhihong; Shi, Shaolin

    2016-01-01

    Toll-like receptor 9 (TLR9) senses bacterial DNA characteristic of unmethylated CpG motifs to induce innate immune response. TLR9 is de novo expressed in podocytes of some patients with glomerular diseases, but its role in podocyte injury remains undetermined. Since TLR9 activates p38 MAPK and NFkB that are known to mediate podocyte apoptosis, we hypothesized that TLR9 induces podocyte apoptosis in glomerular diseases. We treated immortalized podocytes with puromycin aminonucleosides (PAN) and observed podocyte apoptosis, accompanied by TLR9 upregulation. Prevention of TLR9 upregulation by siRNA significantly attenuated NFκB p65 or p38 activity and apoptosis, demonstrating that TLR9 mediates podocyte apoptosis. We next showed that endogenous mitochondrial DNA (mtDNA), whose CpG motifs are also unmethylated, is the ligand for TLR9, because PAN induced mtDNA accumulation in endolysosomes where TLR9 is localized, overexpression of endolysosomal DNase 2 attenuated PAN-induced p38 or p65 activity and podocyte apoptosis, and DNase 2 silencing was sufficient to activate p38 or p65 and induce apoptosis. In PAN-treated rats, TLR9 was upregulated in the podocytes, accompanied by increase of apoptosis markers. Thus, de novo expressed TLR9 may utilize endogenous mtDNA as the ligand to facilitate podocyte apoptosis, a novel mechanism underlying podocyte injury in glomerular diseases. PMID:26934958

  2. Expression of Toll-like receptors in nasal epithelium in allergic rhinitis.

    PubMed

    Renkonen, Jutta; Toppila-Salmi, Sanna; Joenväärä, Sakari; Mattila, Pirkko; Parviainen, Ville; Hagström, Jaana; Haglund, Caj; Lehtonen, Mikko; Renkonen, Risto

    2015-08-01

    Toll-like receptors (TLRs) are important in barrier homeostasis, but their role in airborne allergies is not fully understood. The aim was to evaluate baseline and allergen-induced expression of TLR proteins in nasal epithelium during allergic rhinitis. Nineteen otherwise healthy non-smoking volunteers both allergic to birch pollen and non-allergic controls were enrolled. We took nasal biopsies before and after off-seasonal intranasal birch pollen or diluent challenge. The expression of epithelial TLR1-7, TLR9-10, and MyD88 proteins was immunohistochemically evaluated from the nasal biopsies. The TLR1-3 and TLR5-10 mRNAs were observed by RNA-microarray. Baseline epithelial expression of TLR proteins was wide and identical in controls and atopics. After off-seasonal intranasal birch pollen challenge, a negative change in the expression score of TLR1 and TLR6 proteins was detected in the atopic group. TLR mRNA expression was not affected by birch pollen challenge. Nasal epithelium seems to express all known TLRs. The mechanisms by which TLR1, and TLR6 proteins could affect pollen allergen transport need further studies.

  3. Characterization of toll-like receptors 1-10 in spotted hyenas

    PubMed Central

    Flies, Andrew S.; Maksimoski, Matthew; Mansfield, Linda S.; Weldele, Mary L.; Holekamp, Kay E.

    2014-01-01

    Previous research has shown that spotted hyenas (Crocuta crocuta) regularly survive exposure to deadly pathogens such as rabies, canine distemper virus, and anthrax, suggesting that they have robust immune defenses. Toll-like receptors (TLRs) recognize conserved molecular patterns and initiate a wide range of innate and adaptive immune responses. TLR genes are evolutionarily conserved, and assessing TLR expression in various tissues can provide insight into overall immunological organization and function. Studies of the hyena immune system have been minimal thus far due to the logistical and ethical challenges of sampling and preserving the immunological tissues of this and other long-lived, wild species. Tissue samples were opportunistically collected from captive hyenas humanely euthanized for a separate study. We developed primers to amplify partial sequences for TLRs 1-10, sequenced the amplicons, compared sequence identity to those in other mammals, and quantified TLR expression in lymph nodes, spleens, lungs, and pancreases. Results show that hyena TLR DNA and protein sequences are similar to TLRs in other mammals, and that TLRs 1-10 were expressed in all tissues tested. This information will be useful in the development of new assays to understand the interactions among the hyena immune system, pathogens, and the microbial communities that inhabit hyenas. PMID:24488231

  4. New Insights into the Pathogenesis and Treatment of Necrotizing Enterocolitis: Toll-like Receptors and Beyond

    PubMed Central

    Afrazi, Amin; Sodhi, Chhinder P.; Richardson, Ward; Neal, Matthew; Good, Misty; Siggers, Richard; Hackam, David J.

    2011-01-01

    Necrotizing enterocolitis (NEC) is the leading cause of death from gastrointestinal disease in the preterm infant. The dismal results of current treatment for NEC highlight the urgent need for greater understanding of the pathogenesis of this disease, and the importance of discovering novel, molecular-specific therapies for it. Current dogma indicates that NEC development reflects an abnormal response by the premature infant to the microbial flora that colonizes the gastrointestinal tract, although the mechanisms that mediate these abnormal bacterial-enterocyte interactions, and the reasons for the particularly increased susceptibility of the premature infant to the development of NEC remain incompletely explained. Recent evidence has shed light on an emerging role for the Toll like receptors (TLR's) of the innate immune system as central players in the pathways that signal in response to enteric bacteria resulting in the development of NEC. We now review recent advances in the field of NEC and identify several exciting potential avenues for novel treatments by focusing on abnormal TLR4 signaling in the premature intestine in the pathogenesis of NEC. In so doing, we seek to offer new hope to the patients and their families that are affected by this devastating disorder. PMID:21135755

  5. Drift, not selection, shapes toll-like receptor variation among oceanic island populations.

    PubMed

    Gonzalez-Quevedo, Catalina; Spurgin, Lewis G; Illera, Juan Carlos; Richardson, David S

    2015-12-01

    Understanding the relative role of different evolutionary forces in shaping the level and distribution of functional genetic diversity among natural populations is a key issue in evolutionary and conservation biology. To do so accurately genetic data must be analysed in conjunction with an unambiguous understanding of the historical processes that have acted upon the populations. Here, we focused on diversity at toll-like receptor (TLR) loci, which play a key role in the vertebrate innate immune system and, therefore, are expected to be under pathogen-mediated selection. We assessed TLR variation within and among 13 island populations (grouped into three archipelagos) of Berthelot's pipit, Anthus berthelotii, for which detailed population history has previously been ascertained. We also compared the variation observed with that found in its widespread sister species, the tawny pipit, Anthus campestris. We found strong evidence for positive selection at specific codons in TLR1LA, TLR3 and TLR4. Despite this, we found that at the allele frequency level, demographic history has played the major role in shaping patterns of TLR variation in Berthelot's pipit. Levels of diversity and differentiation within and across archipelagos at all TLR loci corresponded very closely with neutral microsatellite variation and with the severity of the bottlenecks that occurred during colonization. Our study shows that despite the importance of TLRs in combating pathogens, demography can be the main driver of immune gene variation within and across populations, resulting in patterns of functional variation that can persist over evolutionary timescales. PMID:26509790

  6. 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.

  7. Site differences of Toll-like receptor expression in the mucous epithelium of rat small intestine.

    PubMed

    Mantani, Y; Kamezaki, A; Udayanga, K G S; Takahara, E-i; Qi, W M; Kawano, J; Yokoyama, T; Hoshi, N; Kitagawa, H

    2011-10-01

    Toll-like receptors (TLRs) are known to recognize pathogen-associated molecular patterns and might function as receptors to detect microbes. In this study, the distribution of TLR-2, -4 and -9 were immunohistochemically investigated in the rat small intestine. As a result, TLR-2 was detected in the striated borders of villous columnar epithelial cells throughout the small intestine, except for the apices of a small number of intestinal villi. TLR-4 and -9 were detected in the striated borders of the villous columnar epithelial cells only in the duodenum. TLR-4-immunopositive minute granules were found in the apical cytoplasms of epithelial cells, subepithelial spaces and blood capillary lumina. TLR-2 and -4 were detected in the striated borders of undifferentiated epithelial cells and in the luminal substances of the intestinal crypts throughout the small intestine, but TLR-9 was not detected in the crypts throughout the small intestine. Only TLR-4 was detected in the secretory granules of Paneth cells in both the jejunal and ileal intestinal crypts. These findings suggest that duodenal TLRs might monitor indigenous bacteria proliferation in the upper alimentary tract, that TLR-2 might also monitor the proliferation of colonized indigenous bacteria throughout the small intestine, that the lack of TLR-2 at the villous apices might contribute to the settlement of indigenous bacteria, and that TLR-2 and -4 are secreted from intestinal crypts.

  8. Toll-like receptors (TLRs) in aquatic animals: signaling pathways, expressions and immune responses.

    PubMed

    Rauta, Pradipta R; Samanta, Mrinal; Dash, Hirak R; Nayak, Bismita; Das, Surajit

    2014-01-01

    The innate system's recognition of non-self and danger signals is mediated by a limited number of germ-line encoded pattern recognition receptors (PRRs) that recognize pathogen associated molecular patterns (PAMPs). Toll-like receptors (TLRs) are single, non-catalytic, membrane-spanning PRRs present in invertebrates and vertebrates. They act by specifically recognizing PAMPs of a variety of microbes and activate signaling cascades to induce innate immunity. A large number of TLRs have been identified in various aquatic animals of phyla Cnidaria, Annelida, Mollusca, Arthropoda, Echinodermata and Chordata. TLRs of aquatic and warm-blooded higher animals exhibit some distinctive features due to their diverse evolutionary lineages. However, majority of them share conserve signaling pathways in pathogen recognition and innate immunity. Functional analysis of novel TLRs in aquatic animals is very important in understanding the comparative immunology between warm-blooded and aquatic animals. In additions to innate immunity, recent reports have highlighted the additional roles of TLRs in adaptive immunity. Therefore, vaccines against many critical diseases of aquatic animals may be made more effective by supplementing TLR activators which will stimulate dendritic cells. This article describes updated information of TLRs in aquatic animals and their structural and functional relationship with warm-blooded animals.

  9. Regulation of Wound Healing and Organ Fibrosis by Toll-like Receptors

    PubMed Central

    Huebener, Peter; Schwabe, Robert F.

    2013-01-01

    Chronic injury often triggers maladaptive wound healing responses leading to the development of tissue fibrosis and subsequent organ malfunction. Inflammation is a key component of the wound healing process and promotes the development of organ fibrosis. Here, we review the contribution of Toll-like receptors (TLRs) to wound healing with a particular focus on their role in liver, lung, kidney, skin and myocardial fibrosis. We discuss the role of TLRs on distinct cell populations that participate in the repair process following tissue injury, and the contribution of exogenous and endogenous TLR ligands to the wound healing response. Systemic review of the literature shows that TLRs promote tissue repair and fibrosis in many settings, albeit with profound differences between organs. In particular, TLRs exert a pronounced effect on fibrosis in organs with higher exposure to bacterial TLR ligands, such as the liver. Targeting TLR signaling at the ligand or receptor level may represent a novel strategy for the prevention of maladaptive wound healing and fibrosis in chronically injured organs. PMID:23220258

  10. Evolution of an intronic microsatellite polymorphism in Toll-like receptor 2 among primates.

    PubMed

    Yim, Jae-Joon; Adams, Amelia A; Kim, Ju Han; Holland, Steven M

    2006-09-01

    Nonhuman primates express varying responses to Mycobacterium tuberculosis: New World monkeys appear to be resistant to tuberculosis (TB) while Old World monkeys seem to be particularly susceptible. The aim of this study was to elucidate the presence of the regulatory guanine-thymine (GT) repeat polymorphisms in intron 2 of Toll-like receptor 2 (TLR2) associated with the development of TB in humans and to determine any variations in these microsatellite polymorphisms in primates. We sequenced the region encompassing the regulatory GT repeat microsatellites in intron 2 of TLR2 in 12 different nonhuman primates using polymerase chain reaction amplification, TA cloning, and automatic sequencing. The nonhuman primates included for this study were as follows: chimpanzee (Pan troglodytes), bonobo (Pan paniscus), gorilla (Gorilla gorilla), orangutan (Pongo pygmaeus), Celebes ape (Macaca nigra), rhesus monkey (Macaca mulatta), pigtail macaque (Macaca nemestrina), patas monkey (Erythrocebus patas), spider monkey (Ateles geoffroyi), Woolly monkey (Lagothrix lagotricha), tamarin (Saguinus labiatus), and ring-tailed lemur (Lemur catta). Nucleotide sequences encompassing the regulatory GT repeat region are similar across species and are completely conserved in great apes. However, Old World monkeys lack GT repeats altogether, while New World monkeys and ring-tailed lemurs have much more complex structures around the position of the repeats. In conclusion, the genetic structures encompassing the regulatory GT repeats in intron 2 of human TLR2 are similar among nonhuman primates. The sequence is most conserved in New World monkeys and less in Old World monkeys. PMID:16912902

  11. Upregulation of HMGB1, toll-like receptor and RAGE in human Rasmussen's encephalitis.

    PubMed

    Luan, Guoming; Gao, Qing; Zhai, Feng; Chen, Yin; Li, Tianfu

    2016-07-01

    Rasmussen encephalitis (RE) is a rare neurological disorder of childhood characterized by uni-hemispheric inflammation, progressive neurological deficits and intractable focal epilepsy. The pathogenesis of RE is still enigmatic. Activation of endogenous high-mobility group box-1 (HMGB1) and Toll-like receptor (TLR) has been proved to be with pro-inflammatory as well as pro-convulsant effects. We hypothesized that the epileptogenic mechanisms underlying RE are related to activation of HMGB1/TLR signaling. Immunnohistochemistry approach was used to examine the expression of HMGB1, TLR2, TLR4, receptor for advanced glycation end products (RAGE) in surgically resected human epileptic cortical specimens from RE (n=12), and compared that with control cortical issue (n=6). HMGB1 was ubiquitously detected in nuclei of astrocytes while its receptors were not detected in control cortex specimens. Marked expression of the receptors were observed in the lesions of RE. In particular, HMGB1 was in stead detected in cytoplasm of reactive astrocytes in RE cortex, predictive its release from glial cells. Significant greater HMGB1 and its receptors expression in RE vs. control was demonstrated by western blot. These results provide the novel evidence of intrinsic activation of these pro-inflammation pathways in RE, which suggest the specific targets in the treatment of epilepsy associated with RE. PMID:27108105

  12. 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.

  13. Characterization of Toll-like receptors 1-10 in spotted hyenas.

    PubMed

    Flies, Andrew S; Maksimoski, Matthew T; Mansfield, Linda S; Weldele, Mary L; Holekamp, Kay E

    2014-06-01

    Previous research has shown that spotted hyenas (Crocuta crocuta) regularly survive exposure to deadly pathogens such as rabies, canine distemper virus, and anthrax, suggesting that they have robust immune defenses. Toll-like receptors (TLRs) recognize conserved molecular patterns and initiate a wide range of innate and adaptive immune responses. TLR genes are evolutionarily conserved, and assessing TLR expression in various tissues can provide insight into overall immunological organization and function. Studies of the hyena immune system have been minimal thus far due to the logistical and ethical challenges of sampling and preserving the immunological tissues of this and other long-lived, wild species. Tissue samples were opportunistically collected from captive hyenas humanely euthanized for a separate study. We developed primers to amplify partial sequences for TLRs 1-10, sequenced the amplicons, compared sequence identity to those in other mammals, and quantified TLR expression in lymph nodes, spleens, lungs, and pancreases. Results show that hyena TLR DNA and protein sequences are similar to TLRs in other mammals, and that TLRs 1-10 were expressed in all tissues tested. This information will be useful in the development of new assays to understand the interactions among the hyena immune system, pathogens, and the microbial communities that inhabit hyenas. PMID:24488231

  14. Intracellular Toll-like receptor recruitment and cleavage in endosomal/lysosomal organelles.

    PubMed

    Tohmé, Mira; Manoury, Bénédicte

    2014-01-01

    Microbial pathogens are recognized through multiple, distinct receptors such as intracellular Toll-like receptors (TLRs 3, 7, 8, 9, and 13) which reside in the endosomes and lysosomes. TLRs are sensitive to chloroquine, a lysomotropic agent that neutralizes acidic compartments indicating a role for endo/lysosomal proteases for their signaling. Indeed, upon stimulation, full-length TLR7 and 9 are cleaved into a C-terminal fragment and this processing is highly dependent on a cysteine protease named asparagine endopeptidase (AEP) in dendritic cells. A recruitment and a boost in AEP activity, which was induced shortly after TLR7 and 9 stimulation, are shown to promote TLR7 and 9 cleavage and correlate with an increased acidification in endosomes and lysosomes. Moreover, mutating a putative AEP cleavage site in TLR7 or 9 strongly decreases their signaling in DCs, suggesting perhaps a direct cleavage of TLR7 and 9 by AEP. These results demonstrate that TLR7 and 9 require a proteolytic cleavage for their signaling and identified a key endocytic protease playing a critical role in this process. PMID:24377922

  15. Molecular Regulation of Toll-like Receptors in Asthma and COPD

    PubMed Central

    Zuo, Li; Lucas, Kurt; Fortuna, Christopher A.; Chuang, Chia-Chen; Best, Thomas M.

    2015-01-01

    Asthma and chronic obstructive pulmonary disease (COPD) have both been historically associated with significant morbidity and financial burden. These diseases can be induced by several exogenous factors, such as pathogen-associated molecular patterns (PAMPs) (e.g., allergens and microbes). Endogenous factors, including reactive oxygen species, and damage-associated molecular patterns (DAMPs) recognized by toll-like receptors (TLRs), can also result in airway inflammation. Asthma is characterized by the dominant presence of eosinophils, mast cells, and clusters of differentiation (CD)4+ T cells in the airways, while COPD typically results in the excessive formation of neutrophils, macrophages, and CD8+ T cells in the airways. In both asthma and COPD, in the respiratory tract, TLRs are the primary proteins of interest associated with the innate and adaptive immune responses; hence, multiple treatment options targeting TLRs are being explored in an effort to reduce the severity of the symptoms of these disorders. TLR-mediated pathways for both COPD and asthma have their similarities and differences with regards to cell types and the pro-inflammatory cytotoxins present in the airway. Because of the complex TLR cascade, a variety of treatments have been used to minimize airway hypersensitivity and promote bronchodilation. Although unsuccessful at completely alleviating COPD and severe asthmatic symptoms, new studies are focused on possible targets within the TLR cascade to ameliorate airway inflammation. PMID:26617525

  16. RNA mediated toll-like receptor stimulation in health and disease

    PubMed Central

    Dalpke, Alexander H.; Helm, Mark

    2012-01-01

    Besides their well known functions in storage and translation of information nucleic acids have emerged as a target of pattern recognition receptors that drive activation of innate immunity. Due to the paucity of building block monomers used in nucleic acids, discrimination of host and microbial nucleic acids as a means of self/foreign discrimination is a complicated task. Pattern recognition receptors rely on discrimination by sequence, structural features and spatial compartmentalization to differentiate microbial derived nucleic acids from host ones. Microbial nucleic acid detection is important for the sensing of infectious danger and initiating an immune response to microbial attack. Failures in the underlying recognitions systems can have severe consequences: thus, inefficient recognition of microbial nucleic acids may increase susceptibility to infectious diseases. On the other hand, excessive immune responses as a result of failed self/foreign discrimination are associated with autoimmune diseases. This review gives a general overview over the underlying concepts of nucleic acid sensing by Toll-like receptors. Within this general framework, we focus on bacterial RNA and synthetic RNA oligomers. PMID:22617878

  17. Toll-Like Receptor 4 Mediates the Regenerative Effects of Bone Grafts for Calvarial Bone Repair

    PubMed Central

    Wang, Dan; Gilbert, James R.; Shaw, Melissa A.; Shakir, Sameer; Losee, Joseph E.; Billiar, Timothy R.

    2015-01-01

    Craniofacial trauma is difficult to repair and presents a significant burden to the healthcare system. The inflammatory response following bone trauma is critical to initiate healing, serving to recruit inflammatory and progenitor cells and to promote angiogenesis. A role for inflammation in graft-induced bone regeneration has been suggested, but is still not well understood. The current study assessed the impact of Toll-like receptor (TLR4) signaling on calvarial repair in the presence of morselized bone components. Calvarial defects in wild-type and global TLR4−/− knockout mouse strains were treated with fractionated bone components in the presence or absence of a TLR4 neutralizing peptide. Defect healing was subsequently evaluated over 28 days by microcomputed tomography and histology. The matrix-enriched fraction of morselized bone stimulated calvarial bone repair comparably with intact bone graft, although the capacity for grafts to induce calvarial bone repair was significantly diminished by inhibition or genetic ablation of TLR4. Overall, our findings suggest that the matrix component of bone graft stimulates calvarial bone repair in a TLR4-dependent manner. These results support the need to better understand the role of inflammation in the design and implementation of strategies to improve bone healing. PMID:25603990

  18. DNA-polymer conjugates for immune stimulation through Toll-like receptor 9 mediated pathways.

    PubMed

    Levenson, Eric A; Kiick, Kristi L

    2014-03-01

    Oligodeoxynucleotides (ODNs) containing unmethylated CpG dinucleotide motifs are agonists of Toll-like receptor 9 and are currently being investigated for use as vaccine adjuvants through the promotion of type I immunity. Several classes of ODN have been developed which differ in their propensity to aggregate, which in turn alters cytokine profiles and cellular subsets activated. Although aggregation state is correlated with the change in cytokine response, it is unknown if this results from a change in the number of ODNs available for binding and/or the possible engagement of multiple TLR9 molecules. Here, we examined the role of ligand valency on the activation of TLR9 through the synthesis of ODN-poly(acrylic acid) (PAA) conjugates. The compositions and size of the conjugates were characterized by UV-vis spectroscopy, proton nuclear magnetic resonance, gel permeation chromatography and dynamic light scattering. Enzyme-linked immunosorbent assays of cytokine secretion by murine-like macrophages indicate that these ODN-PAA polymer conjugates show enhanced immunostimulation at 100-fold lower concentrations than those required for ODN alone, for both TNF-α and IL-6 release, and are more potent than any other previously reported multivalent ODN constructs. Increasing valency was shown to significantly enhance cytokine expression, particularly for IL-6. Knockdown by siRNA demonstrates that these polymer conjugates are specific to TLR9. Our results define valency as a critical design parameter and polymer conjugation as an advantageous strategy for producing ODN immunomodulatory agents. PMID:24316364

  19. Immune Adjuvant Effect of Molecularly-defined Toll-Like Receptor Ligands

    PubMed Central

    Toussi, Deana N.; Massari, Paola

    2014-01-01

    Vaccine efficacy is optimized by addition of immune adjuvants. However, although adjuvants have been used for over a century, to date, only few adjuvants are approved for human use, mostly aimed at improving vaccine efficacy and antigen-specific protective antibody production. The mechanism of action of immune adjuvants is diverse, depending on their chemical and molecular nature, ranging from non-specific effects (i.e., antigen depot at the immunization site) to specific activation of immune cells leading to improved host innate and adaptive responses. Although the detailed molecular mechanism of action of many adjuvants is still elusive, the discovery of Toll-like receptors (TLRs) has provided new critical information on immunostimulatory effect of numerous bacterial components that engage TLRs. These ligands have been shown to improve both the quality and the quantity of host adaptive immune responses when used in vaccine formulations targeted to infectious diseases and cancer that require both humoral and cell-mediated immunity. The potential of such TLR adjuvants in improving the design and the outcomes of several vaccines is continuously evolving, as new agonists are discovered and tested in experimental and clinical models of vaccination. In this review, a summary of the recent progress in development of TLR adjuvants is presented. PMID:26344622

  20. Toll-like receptor 3 gene polymorphisms in South African Blacks with type 1 diabetes.

    PubMed

    Pirie, F J; Pegoraro, R; Motala, A A; Rauff, S; Rom, L; Govender, T; Esterhuizen, T M

    2005-08-01

    Type 1 diabetes is the consequence of exposure of genetically susceptible individuals to specific environmental precipitants. The innate immune system provides the initial response to exogenous antigen and links with the adaptive immune system. The aim of this study was to assess the role of polymorphisms occurring in the cytoplasmic region of toll-like receptor (TLR) 3 gene and immediate 5' sequence, in subjects of Zulu descent with type 1 diabetes in KwaZulu-Natal, South Africa. Seventy-nine subjects with type 1 diabetes and 74 healthy normal glucose tolerant gender-matched control subjects were studied. Parts of exon 4 and exon 3/intron 3 of the TLR3 gene were studied by polymerase chain reaction, direct sequencing and restriction enzyme digestion with Bts 1. Of the nine polymorphisms studied, a significant association with type 1 diabetes was found for the major allele in the 2593 C/T polymorphism and for the minor alleles in the 2642 C/A and 2690 A/G polymorphisms, which were found to be in complete linkage disequilibrium. Correction of the P-values for the number of alleles studied, however, rendered the results no longer significant. These results suggest that polymorphisms in the TLR3 gene, which is part of the innate immune system, may be associated with type 1 diabetes in this population. PMID:16029432

  1. Toll-Like Receptor Polymorphisms, Inflammatory and Infectious Diseases, Allergies, and Cancer

    PubMed Central

    2013-01-01

    Toll-like receptors (TLRs) are germ-line-encoded innate immune sensors that recognize conserved microbial structures and host alarmins and signal expression of MHC proteins, costimulatory molecules, and inflammatory mediators by macrophages, neutrophils, dendritic cells, and other cell types. These processes activate immediate and early mechanisms of innate host defense, as well as initiate and orchestrate adaptive immune responses. Several single-nucleotide polymorphisms (SNPs) within the TLR genes have been associated with altered susceptibility to infectious, inflammatory, and allergic diseases, and have been found to play a role in tumorigenesis. Critical advances in our understanding of innate immune functions and genome-wide association studies (GWAS) have uncovered complex interactions of genetic polymorphisms within TLRs and environmental factors. However, conclusions obtained in the course of such analyses are restricted by limited power of many studies that is likely to explain controversial findings. Further, linkages to certain ethnic backgrounds, gender, and the presence of multigenic effects further complicate the interpretations of how the TLR SNPs affect immune responses. For many TLRs, the molecular mechanisms by which SNPs impact receptor functions remain unknown. In this review, I have summarized current knowledge about the TLR polymorphisms, their impact on TLR signaling, and associations with various inflammatory, infectious, allergic diseases and cancers, and discussed the directions of future scientific research. PMID:23675778

  2. Kidney Expression of Toll Like Receptors in Lupus Nephritis: Quantification and Clinicopathological Correlations

    PubMed Central

    Miranda, Francesca; Bombardieri, Michele; Valesini, Guido

    2016-01-01

    Objective. The study aimed at locating and quantifying Toll Like Receptor (TLR) 3, 7, 8, and 9 expression in kidney of patients with lupus nephritis (LN) and correlating them with clinicopathological features. Methods. Kidney sections from 26 LN patients and 4 controls were analyzed by immunohistochemistry using anti-human TLR3, TLR7, TLR8, and TLR9 polyclonal antibodies; the number of TLR-positive nuclei/mm2 was evaluated on digitalized images. Results. Compared to controls, LN showed a significantly higher amount of glomerular and tubulointerstitial TLR9 (p = 0.003 and p = 0.007), whole and tubulointerstitial TLR3 (p = 0.026 and p = 0.031), and a higher tubulointerstitial TLR7 (p = 0.022). TLR9 positively correlated with activity index (p = 0.0063) and tubular TLR7 with chronicity index (p = 0.026). TLR9 positively correlated with Renal-SLEDAI (p = 0.01). Conclusions. This is the first study quantifying kidney expressions of TLRs in LN patients; the results show an overexpression of TLR3, TLR7, and TLR9 and demonstrate a correlation with clinicopathological indices supporting a role of these mediators in the pathogenesis of LN. PMID:27635115

  3. 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.

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

    PubMed

    Zakeri, Amin; Borji, Hassan; Haghparast, Alireza

    2016-05-01

    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. PMID:27120222

  5. Characterization of Toll-like receptors 1-10 in spotted hyenas.

    PubMed

    Flies, Andrew S; Maksimoski, Matthew T; Mansfield, Linda S; Weldele, Mary L; Holekamp, Kay E

    2014-06-01

    Previous research has shown that spotted hyenas (Crocuta crocuta) regularly survive exposure to deadly pathogens such as rabies, canine distemper virus, and anthrax, suggesting that they have robust immune defenses. Toll-like receptors (TLRs) recognize conserved molecular patterns and initiate a wide range of innate and adaptive immune responses. TLR genes are evolutionarily conserved, and assessing TLR expression in various tissues can provide insight into overall immunological organization and function. Studies of the hyena immune system have been minimal thus far due to the logistical and ethical challenges of sampling and preserving the immunological tissues of this and other long-lived, wild species. Tissue samples were opportunistically collected from captive hyenas humanely euthanized for a separate study. We developed primers to amplify partial sequences for TLRs 1-10, sequenced the amplicons, compared sequence identity to those in other mammals, and quantified TLR expression in lymph nodes, spleens, lungs, and pancreases. Results show that hyena TLR DNA and protein sequences are similar to TLRs in other mammals, and that TLRs 1-10 were expressed in all tissues tested. This information will be useful in the development of new assays to understand the interactions among the hyena immune system, pathogens, and the microbial communities that inhabit hyenas.

  6. The use of Toll-like receptor 7/8 agonists as vaccine adjuvants.

    PubMed

    Vasilakos, John P; Tomai, Mark A

    2013-07-01

    Small molecule Toll-like receptor (TLR) 7/8 agonists have demonstrated potential as vaccine adjuvants, since they directly activate APCs and can enhance both humoral and cellular immune responses, especially Th1 responses. Although the natural ligands for TLR7 and TLR8 are ssRNA, the vast majority of vaccine studies performed thus far have been performed with synthetic small molecule imidazoquinolines, such as imiquimod and resiquimod. Despite the approved clinical use of the topical TLR7 agonist, imiquimod (Aldara(®) Imiquimod 5% cream; 3M, MN, USA), for external genital warts, superficial basal cell carcinoma and actinic keratosis, no vaccines using TLR7, TLR8 or TLR7/8 agonists have progressed beyond early-phase clinical studies thus far. This review will highlight the nonclinical and clinical studies that indicate promise for TLR7/8 ligands as vaccine adjuvants, reasons for inconsistent results thus far, problems with current technology and potential paths forward for TLR7/8 agonists as vaccine adjuvants.

  7. 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

  8. 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

  9. Ectodomain Architecture Affects Sequence and Functional Evolution of Vertebrate Toll-like Receptors.

    PubMed

    Wang, Jinlan; Zhang, Zheng; Liu, Jing; Zhao, Jing; Yin, Deling

    2016-01-01

    Toll-like receptors (TLRs) are crucial components of innate immunity that specifically recognize diverse pathogen-associated molecular patterns from pathogens. The continuous hydrogen-bond network (asparagine ladder) formed among the asparagine residues on the concave surfaces of neighboring leucine-rich repeat modules assists in stabilizing the overall shape of TLR ectodomains responsible for ligand recognition. Analysis of 28 types of vertebrate TLRs showed that their ectodomains possessed three types of architectures: a single-domain architecture with an intact asparagine ladder, a three-domain architecture with the ladder interrupted in the middle, and a trans-three-domain architecture with the ladder broken in both termini. Based on a phylogenetic analysis, the three vertebrate TLR architectures arose during early evolution. The 1428 vertebrate TLRs can be divided into eight families based on sequence and structural differences. TLRs ligand specificities are affected by their ectodomain architectures. Three-domain TLRs bind hydrophobic ligands, whereas single-domain and trans-three-domain TLRs mainly recognize hydrophilic ligands. Analysis of 39 vertebrate genomes suggested that the number of single-domain TLR genes in terrestrial vertebrate genomes decreased by half compared to aquatic vertebrate genomes. Single-domain TLR genes underwent stronger purifying selective pressures than three-domain TLR genes in mammals. Overall, ectodomain architecture influences the sequence and functional evolution of vertebrate TLRs. PMID:27216145

  10. Toll-Like Receptor 4 Reduces Oxidative Injury via Glutathione Activity in Sheep.

    PubMed

    Deng, Shoulong; Yu, Kun; Wu, Qian; Li, Yan; Zhang, Xiaosheng; Zhang, Baolu; Liu, Guoshi; Liu, Yixun; Lian, Zhengxing

    2016-01-01

    Toll-like receptor 4 (TLR4) is an important sensor of Gram-negative bacteria and can trigger activation of the innate immune system. Increased activation of TLR4 can lead to the induction of oxidative stress. Herein, the pathway whereby TLR4 affects antioxidant activity was studied. In TLR4-overexpressing sheep, TLR4 expression was found to be related to the integration copy number when monocytes were challenged with lipopolysaccharide (LPS). Consequently, production of malondialdehyde (MDA) was increased, which could increase the activation of prooxidative stress enzymes. Meanwhile, activation of an antioxidative enzyme, glutathione peroxidase (GSH-Px), was increased. Real-time PCR showed that expression of activating protein-1 (AP-1) and the antioxidative-related genes was increased. By contrast, the expression levels of superoxide dismutase 1 (SOD1) and catalase (CAT) were reduced. In transgenic sheep, glutathione (GSH) levels were dramatically reduced. Furthermore, transgenic sheep were intradermally injected with LPS in each ear. The amounts of inflammatory infiltrates were correlated with the number of TLR4 copies that were integrated in the genome. Additionally, the translation of γ-glutamylcysteine synthetase (γ-GCS) was increased. Our findings indicated that overexpression of TLR4 in sheep could ameliorate oxidative injury through GSH secretion that was induced by LPS stimulation. Furthermore, TLR4 promoted γ-GCS translation through the AP-1 pathway, which was essential for GSH synthesis. PMID:26640618

  11. Toll-like receptor 4 in experimental kidney transplantation: early mediator of endogenous danger signals.

    PubMed

    Bergler, Tobias; Hoffmann, Ute; Bergler, Elisabeth; Jung, Bettina; Banas, Miriam C; Reinhold, Stephan W; Krämer, Bernhard K; Banas, Bernhard

    2012-01-01

    The role of toll-like receptors (TLRs) has been described in the pathogenesis of renal ischemia/reperfusion injury, but data on the expression and function of TLR4 during renal allograft damage are still scarce. We analyzed the expression of TLR4 in an experimental rat model 6 and 28 days after allogeneic kidney transplantation in comparison to control rats and rats after syngeneic transplantation. On day 6, a significant induction in TLR4 expression--restricted to the glomerular compartment--was found in acute rejecting allografts only. TLR4 expression strongly correlated with renal function, and TLR4 induction was accompanied by a significant increase in CC chemokine expression within the graft as well as in urinary CC chemokine excretion. TLR4 induction may be caused by an influx of macrophages as well as TLR4-expressing intrinsic renal cells. Fibrinogen deposition in renal allografts correlated with renal TLR4 expression and may act as a potent stimulator of chemokine release via TLR4 activation. This study provides, for the first time, data about the precise intrarenal localization and TLR4 induction after experimental kidney transplantation. It supports the hypothesis that local TLR4 activation by endogenous ligands may be one pathological link from unspecific primary allograft damage to subsequent chemokine release, infiltration and activation of immune cells leading to deterioration of renal function and induction of renal fibrosis. PMID:23171961

  12. Toll-Like Receptors: Insights into Their Possible Role in the Pathogenesis of Lyme Neuroborreliosis▿

    PubMed Central

    Bernardino, Andrea L. F.; Myers, Tereance A.; Alvarez, Xavier; Hasegawa, Atsuhiko; Philipp, Mario T.

    2008-01-01

    Lyme neuroborreliosis is likely caused by inflammatory effects of the tick-borne spirochete Borrelia burgdorferi on the nervous system. Microglia, the resident macrophage cells within the central nervous system (CNS), are important in initiating an immune response to microbial products. In addition, astrocytes, the major CNS glial cell type, also can contribute to brain inflammation. TLRs (Toll-like receptors) are used by glial cells to recognize pathogen-associated molecular patterns (PAMPs), mediate innate responses, and initiate an acquired immune response. Here we hypothesize that because of their PAMP specificities, TLR1, -2, -5, and -9 may be involved in the pathogenesis of Lyme neuroborreliosis. Previous reports have shown that the rhesus monkey is the only animal model to exhibit signs of Lyme neuroborreliosis. Therefore, we used primary cultures of rhesus astrocytes and microglia to determine the role of TLRs in mediating proinflammatory responses to B. burgdorferi. The results indicate that microglia and astrocytes respond to B. burgdorferi through TLR1/2 and TLR5. In addition, we observed that phagocytosis of B. burgdorferi by microglia enhances not only the expression of TLR1, -2, and -5, but also that of TLR4. Taken together, our data provide proof of the concept that astrocyte and microglial TLR1, -2, and -5 are involved in the in vivo response of primate glial cells to B. burgdorferi. The proinflammatory molecules elicited by these TLR-mediated responses could be a significant factor in the pathogenesis of Lyme neuroborreliosis. PMID:18694963

  13. The evolution of bat nucleic acid-sensing Toll-like receptors.

    PubMed

    Escalera-Zamudio, Marina; Zepeda-Mendoza, M Lisandra; Loza-Rubio, Elizabeth; Rojas-Anaya, Edith; Méndez-Ojeda, Maria L; Arias, Carlos F; Greenwood, Alex D

    2015-12-01

    We characterized the nucleic acid-sensing Toll-like receptors (TLR) of a New World bat species, the common vampire bat (Desmodus rotundus), and through a comparative molecular evolutionary approach searched for general adaptation patterns among the nucleic acid-sensing TLRs of eight different bats species belonging to three families (Pteropodidae, Vespertilionidae and Phyllostomidae). We found that the bat TLRs are evolving slowly and mostly under purifying selection and that the divergence pattern of such receptors is overall congruent with the species tree, consistent with the evolution of many other mammalian nuclear genes. However, the chiropteran TLRs exhibited unique mutations fixed in ligand-binding sites, some of which involved nonconservative amino acid changes and/or targets of positive selection. Such changes could potentially modify protein function and ligand-binding properties, as some changes were predicted to alter nucleic acid binding motifs in TLR 9. Moreover, evidence for episodic diversifying selection acting specifically upon the bat lineage and sublineages was detected. Thus, the long-term adaptation of chiropterans to a wide variety of environments and ecological niches with different pathogen profiles is likely to have shaped the evolution of the bat TLRs in an order-specific manner. The observed evolutionary patterns provide evidence for potential functional differences between bat and other mammalian TLRs in terms of resistance to specific pathogens or recognition of nucleic acids in general. PMID:26503258

  14. Toll-like receptor 7 affects the pathogenesis of non-alcoholic fatty liver disease

    PubMed Central

    Kim, Sokho; Park, Surim; Kim, Bumseok; Kwon, Jungkee

    2016-01-01

    Recently, a possible link between toll-like receptor 7 (TLR7) and liver disease was suggested, although it was limited to fibrosis. Based on this report, we investigated whether TLR7 has a pivotal role in non-alcoholic fatty liver disease (NAFLD). The TLR7 signaling pathway, which is activated by imiquimod (TLR7 ligand) naturally, induced autophagy and released insulin-like growth factor 1 (IGF-1) into medium from hepatocytes. Lipid accumulation induced by unsaturated fatty acid (UFA; arachidonic acid:oleic acid = 1:1) in hepatocytes, was attenuated in TLR7 and autophagy activation. Interestingly, TLR7 activation attenuated UFA-induced lipid peroxidation products, such as malondialdehyde (MDA) and 4-Hydroxy-2-Nonenal (4-HNE). To clarify a possible pathway between TLR7 and lipid peroxidation, we treated hepatocytes with MDA and 4-HNE. MDA and 4-HNE induced 2-folds lipid accumulation in UFA-treated hepatocytes via blockade of the TLR7 signaling pathway’s IGF-1 release compared to only UFA-treated hepatocytes. In vivo experiments carried out with TLR7 knockout mice produced results consistent with in vitro experiments. In conclusion, TLR7 prevents progression of NAFLD via induced autophagy and released IGF-1 from liver. These findings suggest a new therapeutic strategy for the treatment of NAFLD. PMID:27279075

  15. Molecular cloning and characterisation of the griffon vulture (Gyps fulvus) toll-like receptor 1.

    PubMed

    de la Lastra, José Manuel Pérez; de la Fuente, José

    2007-01-01

    The toll-like receptor (TLR) family is an ancient pattern recognition receptor family, conserved from insects to mammals. Members of the TLR family are vital to immune function through the sensing of pathogenic agents and initiation of an appropriate immune response. In this study, we cloned a cDNA encoding for a griffon vulture (Gyps fulvus) orthologue of mammalian TLR1 (CD281). The predicted 650 amino acid sequence comprised an extracellular domain with five leucine-rich repeats (LRR) and an LRR-C-terminal (LRR-CT) motif, followed by a 23 amino acid transmembrane segment, and a 190 amino acid intracytoplasmic region containing the Toll/IL-1R (TIR) domain. Vulture TLR1 and TIR domain showed 64% and 86% amino acid sequence similarity with chicken sequences. The tissue and cell expression pattern of vulture TLR1 were analysed by real time-PCR (RT-PCR) and correlated with the ability to respond to various pathogenic challenges. Despite the similarities in the overall structure and expression pattern of vulture TLR1 with other vertebrate TLRs, the length of the vulture TLR ectodomain, number and position of LRRs and N-glycosylation sites suggest structural differences that may have functional implications.

  16. Network Analysis of Neurodegenerative Disease Highlights a Role of Toll-Like Receptor Signaling

    PubMed Central

    Nguyen, Thanh-Phuong; Morine, Melissa J.

    2014-01-01

    Despite significant advances in the study of the molecular mechanisms altered in the development and progression of neurodegenerative diseases (NDs), the etiology is still enigmatic and the distinctions between diseases are not always entirely clear. We present an efficient computational method based on protein-protein interaction network (PPI) to model the functional network of NDs. The aim of this work is fourfold: (i) reconstruction of a PPI network relating to the NDs, (ii) construction of an association network between diseases based on proximity in the disease PPI network, (iii) quantification of disease associations, and (iv) inference of potential molecular mechanism involved in the diseases. The functional links of diseases not only showed overlap with the traditional classification in clinical settings, but also offered new insight into connections between diseases with limited clinical overlap. To gain an expanded view of the molecular mechanisms involved in NDs, both direct and indirect connector proteins were investigated. The method uncovered molecular relationships that are in common apparently distinct diseases and provided important insight into the molecular networks implicated in disease pathogenesis. In particular, the current analysis highlighted the Toll-like receptor signaling pathway as a potential candidate pathway to be targeted by therapy in neurodegeneration. PMID:24551850

  17. Pivotal role for neuronal Toll-like receptors in ischemic brain injury and functional deficits

    PubMed Central

    Tang, Sung-Chun; Arumugam, Thiruma V.; Xu, Xiangru; Cheng, Aiwu; Mughal, Mohamed R.; Jo, Dong Gyu; Lathia, Justin D.; Siler, Dominic A.; Chigurupati, Srinivasulu; Ouyang, Xin; Magnus, Tim; Camandola, Simonetta; Mattson, Mark P.

    2007-01-01

    The innate immune system senses the invasion of pathogenic microorganisms and tissue injury through Toll-like receptors (TLR), a mechanism thought to be limited to immune cells. We now report that neurons express several TLRs, and that the levels of TLR2 and -4 are increased in neurons in response to IFN-γ stimulation and energy deprivation. Neurons from both TLR2 knockout and -4 mutant mice were protected against energy deprivation-induced cell death, which was associated with decreased activation of a proapoptotic signaling cascade involving jun N-terminal kinase and the transcription factor AP-1. TLR2 and -4 expression was increased in cerebral cortical neurons in response to ischemia/reperfusion injury, and the amount of brain damage and neurological deficits caused by a stroke were significantly less in mice deficient in TLR2 or -4 compared with WT control mice. Our findings establish a proapoptotic signaling pathway for TLR2 and -4 in neurons that may render them vulnerable to ischemic death. PMID:17693552

  18. Characterization of promoter sequence of toll-like receptor genes in Vechur cattle

    PubMed Central

    Lakshmi, R.; Jayavardhanan, K. K.; Aravindakshan, T. V.

    2016-01-01

    Aim: To analyze the promoter sequence of toll-like receptor (TLR) genes in Vechur cattle, an indigenous breed of Kerala with the sequence of Bos taurus and access the differences that could be attributed to innate immune responses against bovine mastitis. Materials and Methods: Blood samples were collected from Jugular vein of Vechur cattle, maintained at Vechur cattle conservation center of Kerala Veterinary and Animal Sciences University, using an acid-citrate-dextrose anticoagulant. The genomic DNA was extracted, and polymerase chain reaction was carried out to amplify the promoter region of TLRs. The amplified product of TLR2, 4, and 9 promoter regions was sequenced by Sanger enzymatic DNA sequencing technique. Results: The sequence of promoter region of TLR2 of Vechur cattle with the B. taurus sequence present in GenBank showed 98% similarity and revealed variants for four sequence motifs. The sequence of the promoter region of TLR4 of Vechur cattle revealed 99% similarity with that of B. taurus sequence but not reveals significant variant in motifregions. However, two heterozygous loci were observed from the chromatogram. Promoter sequence of TLR9 gene also showed 99% similarity to B. taurus sequence and revealed variants for four sequence motifs. Conclusion: The results of this study indicate that significant variation in the promoter of TLR2 and 9 genes in Vechur cattle breed and may potentially link the influence the innate immunity response against mastitis diseases. PMID:27397987

  19. Curdlan activates dendritic cells through dectin-1 and toll-like receptor 4 signaling.

    PubMed

    Kim, Hyung Sook; Park, Ki Hwan; Lee, Hong Kyung; Kim, Ji Sung; Kim, Yong Guk; Lee, Jae Hee; Kim, Ki Hun; Yun, Jieun; Hwang, Bang Yeon; Hong, Jin Tae; Kim, Youngsoo; Han, Sang-Bae

    2016-10-01

    Curdlan, a β-1,3-glucan isolated from Alcaligenes faecalis, is an agonist of dectin-1 in various immune cells, including dendritic cells (DCs). However, whether curdlan also activates DCs through other receptors remains unknown. In this study, we found that curdlan activates DCs through dectin-1 and toll-like receptor 4 (TLR4). Curdlan increased the expression levels of surface molecules (CD40, CD80, CD86, and MHC-I/II), the production of cytokines (IL-12, IL-1β, TNF-α, and IFN-β), migration toward MIP-3β, and allogeneic T cell stimulation activity of DCs. Curdlan increased the phosphorylation of Syk, Raf-1, Akt, MAPKs, IKK, and NF-κB p65 in DCs. However, curdlan only slightly activated DCs transfected with small interfering RNAs against dectin-1 or TLR4 and C3H/HeJ DCs, which have non-functional TLR4, in comparison with control DCs. Curdlan increased antitumor activity of DCs in a syngeneic tumor model. In summary, our data show that curdlan activates DCs through dectin-1 and TLR4 signaling and the combination of curdlan and DCs efficiently inhibit tumor growth in mice.

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

    PubMed

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

    2015-01-01

    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, drugprimed 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.

  1. 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. ?? 2005 Elsevier Inc. All rights reserved.

  2. Berberine reduces Toll-like receptor-mediated macrophage migration by suppression of Src enhancement.

    PubMed

    Cheng, Wei-Erh; Ying Chang, Miao; Wei, Jyun-Yan; Chen, Yen-Jen; Maa, Ming-Chei; Leu, Tzeng-Horng

    2015-06-15

    Berberine is an isoquinoline with anti-inflammatory activity. We previously demonstrated that there was a loop of signal amplification between nuclear factor kappa B and Src for macrophage mobility triggered by the engagement of Toll-like receptors (TLRs). The simultaneous suppression of lipopolysaccharide (LPS)-mediated upregulation of inducible nitric oxide synthase, cyclooxygenase 2, and cell mobility in berberine-treated macrophages suggested Src might be a target of berberine. Indeed, th reduced migration, greatly suppressed Src induction in both protein and RNA transcript by berberine were observed in macrophages exposed to LPS, peptidoglycan, polyinosinic-polycytidylic acid, and CpG-oligodeoxynucleotides. In addition to Src induction, berberine also inhibited LPS-mediated Src activation in Src overexpressing macrophages and S-nitroso-N-acetylpenicillamine (a nitric oxide donor) could partly restore it. Moreover, berberine suppressed Src activity in fibronectin-stimulated macrophages and in v-Src transformed cells. These results implied that by effectively reducing Src expression and activity, berberine inhibited TLR-mediated cell motility in macrophages.

  3. γ-Glutamyltranspeptidase is an endogenous activator of Toll-like receptor 4-mediated osteoclastogenesis

    PubMed Central

    Moriwaki, Sawako; Into, Takeshi; Suzuki, Keiko; Miyauchi, Mutsumi; Takata, Takashi; Shibayama, Keigo; Niida, Shumpei

    2016-01-01

    Chronic inflammation-associated bone destruction, which is observed in rheumatoid arthritis (RA) and periodontitis, is mediated by excessive osteoclastogenesis. We showed previously that γ-glutamyltranspeptidase (GGT), an enzyme involved in glutathione metabolism, acts as an endogenous activator of such pathological osteoclastogenesis, independent of its enzymatic activity. GGT accumulation is clinically observed in the joints of RA patients, and, in animals, the administration of recombinant GGT to the gingival sulcus as an in vivo periodontitis model induces an increase in the number of osteoclasts. However, the underlying mechanisms of this process remain unclear. Here, we report that Toll-like receptor 4 (TLR4) recognizes GGT to activate inflammation-associated osteoclastogenesis. Unlike lipopolysaccharide, GGT is sensitive to proteinase K treatment and insensitive to polymyxin B treatment. TLR4 deficiency abrogates GGT-induced osteoclastogenesis and activation of NF-κB and MAPK signaling in precursor cells. Additionally, GGT does not induce osteoclastogenesis in cells lacking the signaling adaptor MyD88. The administration of GGT to the gingival sulcus induces increased osteoclastogenesis in wild-type mice, but does not induce it in TLR4-deficient mice. Our findings elucidate a novel mechanism of inflammation-associated osteoclastogenesis, which involves TLR4 recognition of GGT and subsequent activation of MyD88-dependent signaling. PMID:27775020

  4. Diversity in the Toll-Like Receptor Genes of the African Penguin (Spheniscus demersus)

    PubMed Central

    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. PMID:27760133

  5. The CNS role of Toll-like receptor 4 in innate neuroimmunity and painful neuropathy.

    PubMed

    Tanga, Flobert Y; Nutile-McMenemy, Nancy; DeLeo, Joyce A

    2005-04-19

    Neuropathic pain remains a prevalent and persistent clinical problem because of our incomplete understanding of its pathogenesis. This study demonstrates for the first time, to our knowledge, a critical role for CNS innate immunity by means of microglial Toll-like receptor 4 (TLR4) in the induction phase of behavioral hypersensitivity in a mouse and rat model of neuropathy. We hypothesized that after L5 nerve transection, CNS neuroimmune activation and subsequent cytokine expression are triggered by the stimulation of microglial membrane-bound TLR4. To test this hypothesis, experiments were undertaken to assess tactile and thermal hypersensitivity in genetically altered (i.e., TLR4 knockout and point-mutant) mice after L5 nerve transection. In a complementary study, TLR4 antisense oligodeoxynucleotide (ODN) was administered intrathecally to L5 spinal nerve injured rats to reduce the expression of spinal TLR4. Both the genetically altered mice and the rats treated with TLR4 antisense ODN displayed significantly attenuated behavioral hypersensitivity and decreased expression of spinal microglial markers and proinflammatory cytokines as compared with their respective control groups. This finding shows that TLR4 contributes to the initiation of CNS neuroimmune activation after L5 nerve transection. Further understanding of this early, specific, innate CNS/microglial response and how it leads to sustained glial/neuronal hypersensitivity may point to new therapies for the prevention and treatment of neuropathic pain syndromes. PMID:15809417

  6. The CNS role of Toll-like receptor 4 in innate neuroimmunity and painful neuropathy

    PubMed Central

    Tanga, Flobert Y.; Nutile-McMenemy, Nancy; DeLeo, Joyce A.

    2005-01-01

    Neuropathic pain remains a prevalent and persistent clinical problem because of our incomplete understanding of its pathogenesis. This study demonstrates for the first time, to our knowledge, a critical role for CNS innate immunity by means of microglial Toll-like receptor 4 (TLR4) in the induction phase of behavioral hypersensitivity in a mouse and rat model of neuropathy. We hypothesized that after L5 nerve transection, CNS neuroimmune activation and subsequent cytokine expression are triggered by the stimulation of microglial membrane-bound TLR4. To test this hypothesis, experiments were undertaken to assess tactile and thermal hypersensitivity in genetically altered (i.e., TLR4 knockout and point-mutant) mice after L5 nerve transection. In a complementary study, TLR4 antisense oligodeoxynucleotide (ODN) was administered intrathecally to L5 spinal nerve injured rats to reduce the expression of spinal TLR4. Both the genetically altered mice and the rats treated with TLR4 antisense ODN displayed significantly attenuated behavioral hypersensitivity and decreased expression of spinal microglial markers and proinflammatory cytokines as compared with their respective control groups. This finding shows that TLR4 contributes to the initiation of CNS neuroimmune activation after L5 nerve transection. Further understanding of this early, specific, innate CNS/microglial response and how it leads to sustained glial/neuronal hypersensitivity may point to new therapies for the prevention and treatment of neuropathic pain syndromes. PMID:15809417

  7. The Contributing Role of CD14 in Toll-Like Receptor 4 Dependent Neuropathic Pain

    PubMed Central

    Cao, Ling; Tanga, Flobert Y; DeLeo, Joyce A.

    2009-01-01

    We have previously demonstrated that central nervous system (CNS) toll-like receptor 4 (TLR4) plays a key role in the development of behavioral hypersensitivity in a rodent model of neuropathic pain, spinal nerve L5 transection (L5Tx). TLR4 is a well-known receptor for lipopolysaccharide (LPS) in innate immune responses. In the current study, we further investigated the role of CD14, an accessory molecule in the LPS-TLR4 signaling pathway, in the development of L5Tx-induced neuropathic pain. CD14 knockout (KO) mice displayed significantly decreased behavioral sensitivity (mechanical allodynia and thermal hyperalgesia) as early as day 1 post-L5Tx, indicating a nociceptive role of CD14. By flow cytometric analyses, we observed significantly elevated microglial surface CD14 expression in the ipsilateral lumbar spinal cord 3 days post-L5Tx, as well as remarkable increases in microglial size (via forward scatter (FSC)) and granularity (via side scatter (SSC)). Further, intrathecal injection of soluble CD14 induced significantly greater mechanical hypersensitivity in wild type (C3H/HeN) mice compared to TLR4-deficient (C3H/HeJ) mice. Together, these data demonstrate that CD14 plays a contributing role in TLR4-dependent nerve injury-induced neuropathic pain. PMID:18976692

  8. Toll-like receptor 4 mediates the regenerative effects of bone grafts for calvarial bone repair.

    PubMed

    Wang, Dan; Gilbert, James R; Shaw, Melissa A; Shakir, Sameer; Losee, Joseph E; Billiar, Timothy R; Cooper, Gregory M

    2015-04-01

    Craniofacial trauma is difficult to repair and presents a significant burden to the healthcare system. The inflammatory response following bone trauma is critical to initiate healing, serving to recruit inflammatory and progenitor cells and to promote angiogenesis. A role for inflammation in graft-induced bone regeneration has been suggested, but is still not well understood. The current study assessed the impact of Toll-like receptor (TLR4) signaling on calvarial repair in the presence of morselized bone components. Calvarial defects in wild-type and global TLR4(-/-) knockout mouse strains were treated with fractionated bone components in the presence or absence of a TLR4 neutralizing peptide. Defect healing was subsequently evaluated over 28 days by microcomputed tomography and histology. The matrix-enriched fraction of morselized bone stimulated calvarial bone repair comparably with intact bone graft, although the capacity for grafts to induce calvarial bone repair was significantly diminished by inhibition or genetic ablation of TLR4. Overall, our findings suggest that the matrix component of bone graft stimulates calvarial bone repair in a TLR4-dependent manner. These results support the need to better understand the role of inflammation in the design and implementation of strategies to improve bone healing.

  9. Distinctive Recognition of Flagellin by Human and Mouse Toll-Like Receptor 5

    PubMed Central

    Forstnerič, Vida; Ivičak-Kocjan, Karolina; Ljubetič, Ajasja; Jerala, Roman; Benčina, Mojca

    2016-01-01

    Toll-like receptor 5 (TLR5) is a receptor of the innate immune system that recognizes flagellin from certain bacterial species and triggers an inflammatory response. The Salmonella dublin flagellin in complex with zebrafish TLR5 has been crystallized previously. In the present study, we extrapolate the structure of this complex using structure-guided mutagenesis to determine the recognition modes of human and mouse TLR5 receptors and demonstrate species-specific differences in flagellin recognition. In general, the recognition mode of the mouse receptor can be said to be more robust in comparison to that of the human receptor. All-atom molecular dynamics simulation showed differences between the two receptors within the primary binding region. Using a functional motility assay, we show that although the highly conserved area of the flagellin analyzed in this study encompasses key structural requirements for flagella formation, a direct correlation between immune recognition and structure on the level of amino acid residues is not observed. PMID:27391968

  10. Paclitaxel induces acute pain via directly activating toll like receptor 4.

    PubMed

    Yan, Xisheng; Maixner, Dylan W; Yadav, Ruchi; Gao, Mei; Li, Pei; Bartlett, Michael G; Weng, Han-Rong

    2015-12-01

    Paclitaxel, a powerful anti-neoplastic drug, often causes pathological pain, which significantly reduces the quality of life in patients. Paclitaxel-induced pain includes pain that occurs immediately after paclitaxel treatment (paclitaxel-associated acute pain syndrome, P-APS) and pain that persists for weeks to years after cessation of paclitaxel treatment (paclitaxel induced chronic neuropathic pain). Mechanisms underlying P-APS remain unknown. In this study, we found that paclitaxel causes acute pain in rodents in a dose-dependent manner. The paclitaxel-induced acute pain occurs within 2 hrs after a single intravenous injection of paclitaxel. This is accompanied by low levels of paclitaxel penetrating into the cerebral spinal fluid and spinal dorsal horn. We demonstrated that an intrathecal injection of paclitaxel induces mechanical allodynia in a dose-dependent manner. Paclitaxel causes activation of toll like receptor 4 (TLR4) in the spinal dorsal horn and dorsal root ganglions. Through activating TLR4, paclitaxel increases glutamatergic synaptic activities and reduces glial glutamate transporter activities in the dorsal horn. Activations of TLR4 are necessary in the genesis of paclitaxel-induced acute pain. The cellular and molecular signaling pathways revealed in this study could provide rationales for the development of analgesics and management strategies for P-APS in patients. PMID:25775962

  11. Ectodomain Architecture Affects Sequence and Functional Evolution of Vertebrate Toll-like Receptors

    PubMed Central

    Wang, Jinlan; Zhang, Zheng; Liu, Jing; Zhao, Jing; Yin, Deling

    2016-01-01

    Toll-like receptors (TLRs) are crucial components of innate immunity that specifically recognize diverse pathogen-associated molecular patterns from pathogens. The continuous hydrogen-bond network (asparagine ladder) formed among the asparagine residues on the concave surfaces of neighboring leucine-rich repeat modules assists in stabilizing the overall shape of TLR ectodomains responsible for ligand recognition. Analysis of 28 types of vertebrate TLRs showed that their ectodomains possessed three types of architectures: a single-domain architecture with an intact asparagine ladder, a three-domain architecture with the ladder interrupted in the middle, and a trans-three-domain architecture with the ladder broken in both termini. Based on a phylogenetic analysis, the three vertebrate TLR architectures arose during early evolution. The 1428 vertebrate TLRs can be divided into eight families based on sequence and structural differences. TLRs ligand specificities are affected by their ectodomain architectures. Three-domain TLRs bind hydrophobic ligands, whereas single-domain and trans-three-domain TLRs mainly recognize hydrophilic ligands. Analysis of 39 vertebrate genomes suggested that the number of single-domain TLR genes in terrestrial vertebrate genomes decreased by half compared to aquatic vertebrate genomes. Single-domain TLR genes underwent stronger purifying selective pressures than three-domain TLR genes in mammals. Overall, ectodomain architecture influences the sequence and functional evolution of vertebrate TLRs. PMID:27216145

  12. 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

    2015-01-01

    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

  13. Kidney Expression of Toll Like Receptors in Lupus Nephritis: Quantification and Clinicopathological Correlations

    PubMed Central

    Miranda, Francesca; Bombardieri, Michele; Valesini, Guido

    2016-01-01

    Objective. The study aimed at locating and quantifying Toll Like Receptor (TLR) 3, 7, 8, and 9 expression in kidney of patients with lupus nephritis (LN) and correlating them with clinicopathological features. Methods. Kidney sections from 26 LN patients and 4 controls were analyzed by immunohistochemistry using anti-human TLR3, TLR7, TLR8, and TLR9 polyclonal antibodies; the number of TLR-positive nuclei/mm2 was evaluated on digitalized images. Results. Compared to controls, LN showed a significantly higher amount of glomerular and tubulointerstitial TLR9 (p = 0.003 and p = 0.007), whole and tubulointerstitial TLR3 (p = 0.026 and p = 0.031), and a higher tubulointerstitial TLR7 (p = 0.022). TLR9 positively correlated with activity index (p = 0.0063) and tubular TLR7 with chronicity index (p = 0.026). TLR9 positively correlated with Renal-SLEDAI (p = 0.01). Conclusions. This is the first study quantifying kidney expressions of TLRs in LN patients; the results show an overexpression of TLR3, TLR7, and TLR9 and demonstrate a correlation with clinicopathological indices supporting a role of these mediators in the pathogenesis of LN.

  14. Role of Toll-like receptors in photodynamic-therapy-elicited host response

    NASA Astrophysics Data System (ADS)

    Korbelik, Mladen

    2004-07-01

    Treatment of solid tumors by photodynamic therapy (PDT) induces a host reaction, coordinated through a network of inflammatory and immune responses, that plays an important role in the therapy outcome. It is suggested that this host response is initiated by altered self-associated endogenous danger signals massively released from PDT-treated tumors. Toll-like receptors, localized predominantly in the membrane of immune cells, are the major sensors of the recognition arm of the innate immune system. The engagement of these receptors by PDT-generated danger signals prompts the activation of the networks of innate immunity signaling pathways leading to the downstream activation of nuclear transcription factors responsible for the transcription of inflammatory/immune response-associated genes. The contribution of PDT-induced host response to the therapeutic outcome depends on the balance between the tissue-destructive action of inflammatory/immune effectors and the impact of concomitantly mobilized negative regulatory mechanisms evolved for controlling the intensity and duration of inflammatory and immune responses.

  15. Type III secretion needle proteins induce cell signaling and cytokine secretion via Toll-like receptors.

    PubMed

    Jessen, Danielle L; Osei-Owusu, Patrick; Toosky, Melody; Roughead, William; Bradley, David S; Nilles, Matthew L

    2014-06-01

    Pathogens are recognized by hosts by use of various receptors, including the Toll-like receptor (TLR) and Nod-like receptor (NLR) families. Ligands for these varied receptors, including bacterial products, are identified by the immune system, resulting in development of innate immune responses. Only a couple of components from type III secretion (T3S) systems are known to be recognized by TLR or NLR family members. Known T3S components that are detected by pattern recognition receptors (PRRs) are (i) flagellin, detected by TLR5 and NLRC4 (Ipaf); and (ii) T3S rod proteins (PrgJ and homologs) and needle proteins (PrgI and homologs), detected by NAIP and the NLRC4 inflammasome. In this report, we characterize the induction of proinflammatory responses through TLRs by the Yersinia pestis T3S needle protein, YscF, the Salmonella enterica needle proteins PrgI and SsaG, and the Shigella needle protein, MxiH. More specifically, we determine that the proinflammatory responses occur through TLR2 and -4. These data support the hypothesis that T3S needles have an unrecognized role in bacterial pathogenesis by modulating immune responses. PMID:24643544

  16. Age-associated inflammation and Toll-like receptor dysfunction prime the lungs for pneumococcal pneumonia

    PubMed Central

    Hinojosa, Ernesto; Boyd, Angela R.; Orihuela, Carlos J.

    2011-01-01

    Background Aging is associated with increased inflammation and risk for community-acquired pneumonia (CAP). Streptococcus pneumoniae co-opts the NFkB-regulated proteins Polymeric immunoglobulin receptor (pIgR) and Platelet-activating factor receptor (PAFr) to attach and invade cells. We sought to determine if aging and chronic inflammation was associated with increased pIgR & PAFr in the lungs and increased susceptibility to S. pneumoniae. Methods Lung protein and mRNA levels were quantitated using Western blot and quantitative PCR. NFkB activation was measured by electrophoretic mobility shift assay. Cytokine levels were measured by cytometric bead analysis. To model chronic inflammation mice were implanted with osmotic pumps that delivered tumor necrosis factor (TNF)α. Results Aged mice and those infused with TNFα had increased levels of pIgR & PAFr in their lungs and were more susceptible to S. pneumoniae. During pneumonia, aged mice had reduced levels of pIgR & PAFr and less NFkB activation despite greater bacterial burden. We determined that aged mice had decreased amounts of lung Toll-like receptors (TLR)-1, 2, and 4 and reduced capacity to respond to S. pneumoniae with pro-inflammatory cytokine production. Conclusions Aged mice, and potentially elderly humans, are more susceptible to pneumonia because of a priming effect of chronic inflammation and TLR dysfunction. PMID:19586419

  17. Bioinformatics analysis of the structural and evolutionary characteristics for toll-like receptor 15

    PubMed Central

    Wang, Jinlan; Chang, Fen

    2016-01-01

    Toll-like receptors (TLRs) play important role in the innate immune system. TLR15 is reported to have a unique role in defense against pathogens, but its structural and evolution characterizations are still poorly understood. In this study, we identified 57 completed TLR15 genes from avian and reptilian genomes. TLR15 clustered into an individual clade and was closely related to family 1 on the phylogenetic tree. Unlike the TLRs in family 1 with the broken asparagine ladders in the middle, TLR15 ectodomain had an intact asparagine ladder that is critical to maintain the overall shape of ectodomain. The conservation analysis found that TLR15 ectodomain had a highly evolutionarily conserved region on the convex surface of LRR11 module, which is probably involved in TLR15 activation process. Furthermore, the protein–protein docking analysis indicated that TLR15 TIR domains have the potential to form homodimers, the predicted interaction interface of TIR dimer was formed mainly by residues from the BB-loops and αC-helixes. Although TLR15 mainly underwent purifying selection, we detected 27 sites under positive selection for TLR15, 24 of which are located on its ectodomain. Our observations suggest the structural features of TLR15 which may be relevant to its function, but which requires further experimental validation. PMID:27257554

  18. Toll-like receptor polymorphisms, inflammatory and infectious diseases, allergies, and cancer.

    PubMed

    Medvedev, Andrei E

    2013-09-01

    Toll-like receptors (TLRs) are germ-line-encoded innate immune sensors that recognize conserved microbial structures and host alarmins and signal expression of MHC proteins, costimulatory molecules, and inflammatory mediators by macrophages, neutrophils, dendritic cells, and other cell types. These processes activate immediate and early mechanisms of innate host defense, as well as initiate and orchestrate adaptive immune responses. Several single-nucleotide polymorphisms (SNPs) within the TLR genes have been associated with altered susceptibility to infectious, inflammatory, and allergic diseases, and have been found to play a role in tumorigenesis. Critical advances in our understanding of innate immune functions and genome-wide association studies (GWAS) have uncovered complex interactions of genetic polymorphisms within TLRs and environmental factors. However, conclusions obtained in the course of such analyses are restricted by limited power of many studies that is likely to explain controversial findings. Further, linkages to certain ethnic backgrounds, gender, and the presence of multigenic effects further complicate the interpretations of how the TLR SNPs affect immune responses. For many TLRs, the molecular mechanisms by which SNPs impact receptor functions remain unknown. In this review, I have summarized current knowledge about the TLR polymorphisms, their impact on TLR signaling, and associations with various inflammatory, infectious, allergic diseases and cancers, and discussed the directions of future scientific research.

  19. Flagellin A Toll-Like Receptor 5 Agonist as an Adjuvant in Chicken Vaccines

    PubMed Central

    Bajwa, Preety; Deb, Rajib; Chellappa, Madhan Mohan; Dey, Sohini

    2014-01-01

    Chicken raised under commercial conditions are vulnerable to environmental exposure to a number of pathogens. Therefore, regular vaccination of the flock is an absolute requirement to prevent the occurrence of infectious diseases. To combat infectious diseases, vaccines require inclusion of effective adjuvants that promote enhanced protection and do not cause any undesired adverse reaction when administered to birds along with the vaccine. With this perspective in mind, there is an increased need for effective better vaccine adjuvants. Efforts are being made to enhance vaccine efficacy by the use of suitable adjuvants, particularly Toll-like receptor (TLR)-based adjuvants. TLRs are among the types of pattern recognition receptors (PRRs) that recognize conserved pathogen molecules. A number of studies have documented the effectiveness of flagellin as an adjuvant as well as its ability to promote cytokine production by a range of innate immune cells. This minireview summarizes our current understanding of flagellin action, its role in inducing cytokine response in chicken cells, and the potential use of flagellin as well as its combination with other TLR ligands as an adjuvant in chicken vaccines. PMID:24451328

  20. 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.

  1. Toll-like receptor 4 mediates the antitumor host response induced by Ganoderma atrum polysaccharide.

    PubMed

    Yu, Qiang; Nie, Shao-Ping; Wang, Jun-Qiao; Huang, Dan-Fei; Li, Wen-Juan; Xie, Ming-Yong

    2015-01-21

    The aim of this study is to investigate the role of Toll-like receptor (TLR) 4 in Ganoderma atrum polysaccharide (PSG-1)-induced antitumor activity. In vitro, the apoptosis rate of S-180 cells was increased in PSG-1-induced peritoneal macrophage derived from C3H/HeN (wild-type) mice, but not from C3H/HeJ (TLR4-deficient) mice. In the S-180 tumor model, phagocytosis, NO and ROS release, phosphorylation of MAPKs and Akt, and expression of NF-κB were increased by PSG-1 in peritoneal macrophage derived from C3H/HeN mice. Furthermore, PSG-1 elevated Th1 cytokine production and enhanced the cytotoxic activity of CTL and NK cells in C3H/HeN mice. In addition, PSG-1 decreased the tumor weight and increased the apoptosis rate and caspase-3 and caspase-9 activities of tumor derived from the C3H/HeN mice. However, none of these activities were observed in C3H/HeJ mice. In summary, these findings demonstrated that the antitumor activity of PSG-1 is mediated by TLR4.

  2. Type III Secretion Needle Proteins Induce Cell Signaling and Cytokine Secretion via Toll-Like Receptors

    PubMed Central

    Jessen, Danielle L.; Osei-Owusu, Patrick; Toosky, Melody; Roughead, William; Bradley, David S.

    2014-01-01

    Pathogens are recognized by hosts by use of various receptors, including the Toll-like receptor (TLR) and Nod-like receptor (NLR) families. Ligands for these varied receptors, including bacterial products, are identified by the immune system, resulting in development of innate immune responses. Only a couple of components from type III secretion (T3S) systems are known to be recognized by TLR or NLR family members. Known T3S components that are detected by pattern recognition receptors (PRRs) are (i) flagellin, detected by TLR5 and NLRC4 (Ipaf); and (ii) T3S rod proteins (PrgJ and homologs) and needle proteins (PrgI and homologs), detected by NAIP and the NLRC4 inflammasome. In this report, we characterize the induction of proinflammatory responses through TLRs by the Yersinia pestis T3S needle protein, YscF, the Salmonella enterica needle proteins PrgI and SsaG, and the Shigella needle protein, MxiH. More specifically, we determine that the proinflammatory responses occur through TLR2 and -4. These data support the hypothesis that T3S needles have an unrecognized role in bacterial pathogenesis by modulating immune responses. PMID:24643544

  3. Bioinformatics analysis of the structural and evolutionary characteristics for toll-like receptor 15.

    PubMed

    Wang, Jinlan; Zhang, Zheng; Chang, Fen; Yin, Deling

    2016-01-01

    Toll-like receptors (TLRs) play important role in the innate immune system. TLR15 is reported to have a unique role in defense against pathogens, but its structural and evolution characterizations are still poorly understood. In this study, we identified 57 completed TLR15 genes from avian and reptilian genomes. TLR15 clustered into an individual clade and was closely related to family 1 on the phylogenetic tree. Unlike the TLRs in family 1 with the broken asparagine ladders in the middle, TLR15 ectodomain had an intact asparagine ladder that is critical to maintain the overall shape of ectodomain. The conservation analysis found that TLR15 ectodomain had a highly evolutionarily conserved region on the convex surface of LRR11 module, which is probably involved in TLR15 activation process. Furthermore, the protein-protein docking analysis indicated that TLR15 TIR domains have the potential to form homodimers, the predicted interaction interface of TIR dimer was formed mainly by residues from the BB-loops and αC-helixes. Although TLR15 mainly underwent purifying selection, we detected 27 sites under positive selection for TLR15, 24 of which are located on its ectodomain. Our observations suggest the structural features of TLR15 which may be relevant to its function, but which requires further experimental validation. PMID:27257554

  4. 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. PMID:27330321

  5. Reconstitution of a Functional Toll-like Receptor 5 Binding Site in Campylobacter jejuni Flagellin*

    PubMed Central

    de Zoete, Marcel R.; Keestra, A. Marijke; Wagenaar, Jaap A.; van Putten, Jos P. M.

    2010-01-01

    Bacterial flagellin is important for intestinal immune homeostasis. Flagellins from most species activate Toll-like receptor 5 (TLR5). The principal bacterial food-borne pathogen Campylobacter jejuni escapes TLR5 recognition, probably due to an alternate flagellin subunit structure. We investigated the molecular basis of TLR5 evasion by aiming to reconstitute TLR5 stimulating activity in live C. jejuni. Both native glycosylated C. jejuni flagellins (FlaA and FlaB) and recombinant proteins purified from Escherichia coli failed to activate NF-κB in HEK293 cells expressing TLR5. Introduction of multiple defined regions from Salmonella flagellin into C. jejuni FlaA via a recombinatorial approach revealed three regions critical for the activation of human and mouse TLR5, including a β-hairpin structure not previously implicated in TLR5 recognition. Surprisingly, this domain was not required for the activation of chicken TLR5, indicating a selective requirement for the β-hairpin in the recognition of mammalian TLR5. Expression of the active chimeric protein in C. jejuni resulted in secreted glycosylated flagellin that induced a potent TLR5 response. Overall, our results reveal a novel structural requirement for TLR5 recognition of bacterial flagellin and exclude flagellin glycosylation as an additional mechanism of bacterial evasion of the TLR5 response. PMID:20164175

  6. Reconstitution of a functional Toll-like receptor 5 binding site in Campylobacter jejuni flagellin.

    PubMed

    de Zoete, Marcel R; Keestra, A Marijke; Wagenaar, Jaap A; van Putten, Jos P M

    2010-04-16

    Bacterial flagellin is important for intestinal immune homeostasis. Flagellins from most species activate Toll-like receptor 5 (TLR5). The principal bacterial food-borne pathogen Campylobacter jejuni escapes TLR5 recognition, probably due to an alternate flagellin subunit structure. We investigated the molecular basis of TLR5 evasion by aiming to reconstitute TLR5 stimulating activity in live C. jejuni. Both native glycosylated C. jejuni flagellins (FlaA and FlaB) and recombinant proteins purified from Escherichia coli failed to activate NF-kappaB in HEK293 cells expressing TLR5. Introduction of multiple defined regions from Salmonella flagellin into C. jejuni FlaA via a recombinatorial approach revealed three regions critical for the activation of human and mouse TLR5, including a beta-hairpin structure not previously implicated in TLR5 recognition. Surprisingly, this domain was not required for the activation of chicken TLR5, indicating a selective requirement for the beta-hairpin in the recognition of mammalian TLR5. Expression of the active chimeric protein in C. jejuni resulted in secreted glycosylated flagellin that induced a potent TLR5 response. Overall, our results reveal a novel structural requirement for TLR5 recognition of bacterial flagellin and exclude flagellin glycosylation as an additional mechanism of bacterial evasion of the TLR5 response. PMID:20164175

  7. Toll-Like Receptor 2 and NLRP3 Cooperate To Recognize a Functional Bacterial Amyloid, Curli

    PubMed Central

    Rapsinski, Glenn J.; Wynosky-Dolfi, Meghan A.; Oppong, Gertrude O.; Tursi, Sarah A.; Wilson, R. Paul; Brodsky, Igor E.

    2014-01-01

    Amyloids are proteins with cross-β-sheet structure that contribute to pathology and inflammation in complex human diseases, including Alzheimer's disease, Parkinson's disease, type II diabetes, and secondary amyloidosis. Bacteria also produce amyloids as a component of their extracellular matrix during biofilm formation. Recently, several human amyloids were shown to activate the NLRP3 inflammasome, leading to the activation of caspase 1 and production of interleukin 1β (IL-1β). In this study, we investigated the activation of the NLRP3 inflammasome by bacterial amyloids using curli fibers, produced by Salmonella enterica serovar Typhimurium and Escherichia coli. Here, we show that curli fibers activate the NLRP3 inflammasome, leading to the production of IL-1β via caspase 1 activation. Investigation of the underlying mechanism revealed that activation of Toll-like receptor 2 (TLR2) by curli fibers is critical in the generation of IL-1β. Interestingly, activation of the NLRP3 inflammasome by curli fibers or by amyloid β of Alzheimer's disease does not cause cell death in macrophages. Overall, these data identify a cross talk between TLR2 and NLRP3 in response to the bacterial amyloid curli and generation of IL-1β as a product of this interaction. PMID:25422268

  8. Macrophage activation: role of toll-like receptors, nitric oxide, and nuclear factor kappa B.

    PubMed

    Billack, Blase

    2006-10-15

    Macrophages play an important role in host-defense and inflammation. In response to an immune challenge, macrophages become activated and produce proinflammatory mediators that contribute to nonspecific immunity. The mediators released by activated macrophages include: superoxide anion; reactive nitrogen intermediates, such as nitric oxide and peroxynitrite; bioactive lipids; and cytokines. Although essential to the immune response, overproduction of certain macrophage-derived mediators during an immune challenge or inflammatory response can result in tissue injury and cellular death. The present report is focused on understanding some of the molecular mechanisms used by macrophages to produce reactive nitrogen intermediates in response to immunostimulatory agents such as heat shock protein 60 and bacterial lipopolysaccharide. The role of Toll-like receptors and transcription factors such as nuclear factor kappa B (NFkappaB) in the innate immune response is also described. A basic understanding of the underlying molecular mechanisms responsible for macrophage activation should serve as a foundation for novel drug development aimed at modulating macrophage activity.

  9. Response of Toll-like receptors in experimental Guillain-Barré syndrome: a kinetic analysis.

    PubMed

    Gries, Manuela; Davies, Laura; Liu, Yang; Bachhuber, Armin; Spiegel, Jörg; Dillmann, Ulrich; Hartmann, Tobias; Fassbender, Klaus; Walter, Silke

    2012-06-19

    Guillain-Barré syndrome (GBS) is an autoimmune disorder caused by the interaction between cellular and humoral immune responses in the peripheral nervous system. Toll-like receptors (TLRs) are key players in innate and have regulatory functions in adaptive immunity. In this study, we systematically examined expression patterns of TLRs in sciatic nerve and lymphoid organs during the disease course of murine experimental autoimmune neuritis and in blood from Guillain-Barré patients. A kinetic response pattern was identified, characterized by a pronounced up-regulation of TLR2, 6 and 11 on T cells and TLR4 and 6 on APCs, while TLR1 expression was decreased. Moreover, an enhanced expression of the disease promoting cytokine Interleukin-(IL)17A was detected. Additional analysis of GBS patients revealed an up-regulation of TLR2, TLR4 and TLR6 mRNA, negatively correlated with disease severity. This first systematic analysis of TLR expression pattern may contribute to elucidating the role of TLRs in GBS pathophysiology.

  10. Modulation of Adult Mesenchymal Stem Cells Activity by Toll-Like Receptors: Implications on Therapeutic Potential

    PubMed Central

    DelaRosa, Olga; Lombardo, Eleuterio

    2010-01-01

    Mesenchymal stem cells (MSCs) are of special interest as therapeutic agents in the settings of both chronic inflammatory and autoimmune diseases. Toll-like receptors (TLR) ligands have been linked with the perpetuation of inflammation in a number of chronic inflammatory diseases due to the permanent exposure of the immune system to TLR-specific stimuli. Therefore, MSCs employed in therapy can be potentially exposed to TLR ligands, which may modulate MSC therapeutic potential in vivo. Recent results demonstrate that MSCs are activated by TLR ligands leading to modulation of the differentiation, migration, proliferation, survival, and immunosuppression capacities. However inconsistent results among authors have been reported suggesting that the source of MSCs, TLR stimuli employed or culture conditions play a role. Notably, activation by TLR ligands has not been reported to modulate the “immunoprivileged” phenotype of MSCs which is of special relevance regarding the use of allogeneic MSC-based therapies. In this review, we discuss the available data on the modulation of MSCs activity through TLR signalling. PMID:20628526

  11. Expression profile of toll like receptors in a range of water buffalo tissues (Bubalus bubalis).

    PubMed

    Vahanan, B Mayil; Raj, G Dhinakar; Pawar, Rahul Mohan Chandra; Gopinath, V P; Raja, A; Thangavelu, A

    2008-11-15

    The present study was carried out to determine the expression profile of toll-like receptors (TLRs) 1-10 in buffalo peripheral blood mononuclear cells (PBMNC), neutrophils, spleen, liver, lung, heart, kidney, ovary and uterus using reverse transcriptase polymerase chain reaction (RT-PCR) with bovine TLR-specific primers The buffalo TLR partial nucleotide sequences had 95-98% nucleotide homology with bovine TLR sequences available in the GenBank. PBMNC expressed all TLRs except TLR1 and neutrophils expressed all TLRs except TLR3. Expression of all TLRs was observed in spleen, lung and liver tissues. Wide range of TLR mRNA expression was observed in heart, which lacked the expression of only TLR10. Among the tissues analyzed kidneys had the least repertoire of TLR expression. The kidney tissue revealed mRNA expression of only TLR2, TLR5, TLR7 and TLR9. Among the reproductive tissues analyzed, uterus expressed a wide range of TLRs such as 2, 5, 7, 8, 9 and 10 while ovary expressed all TLRs except TLR1 indicating their immuno competence.

  12. The Architecture of the TIR Domain Signalosome in the Toll-like Receptor-4 Signaling Pathway.

    PubMed

    Guven-Maiorov, Emine; Keskin, Ozlem; Gursoy, Attila; VanWaes, Carter; Chen, Zhong; Tsai, Chung-Jung; Nussinov, Ruth

    2015-01-01

    Activated Toll-like receptors (TLRs) cluster in lipid rafts and induce pro- and anti-tumor responses. The organization of the assembly is critical to the understanding of how these key receptors control major signaling pathways in the cell. Although several models for individual interactions were proposed, the entire TIR-domain signalosome architecture has not been worked out, possibly due to its complexity. We employ a powerful algorithm, crystal structures and experimental data to model the TLR4 and its cluster. The architecture that we obtain with 8 MyD88 molecules provides the structural basis for the MyD88-templated myddosome helical assembly and receptor clustering; it also provides clues to pro- and anti-inflammatory signaling pathways branching at the signalosome level to Mal/MyD88 and TRAM/TRIF pro- and anti-inflammatory pathways. The assembly of MyD88 death domain (DD) with TRAF3 (anti-viral/anti-inflammatory) and TRAF6 (pro-inflammatory) suggest that TRAF3/TRAF6 binding sites on MyD88 DD partially overlap, as do IRAK4 and FADD. Significantly, the organization illuminates mechanisms of oncogenic mutations, demonstrates that almost all TLR4 parallel pathways are competitive and clarifies decisions at pathway branching points. The architectures are compatible with the currently-available experimental data and provide compelling insights into signaling in cancer and inflammation pathways. PMID:26293885

  13. Drift, not selection, shapes toll-like receptor variation among oceanic island populations.

    PubMed

    Gonzalez-Quevedo, Catalina; Spurgin, Lewis G; Illera, Juan Carlos; Richardson, David S

    2015-12-01

    Understanding the relative role of different evolutionary forces in shaping the level and distribution of functional genetic diversity among natural populations is a key issue in evolutionary and conservation biology. To do so accurately genetic data must be analysed in conjunction with an unambiguous understanding of the historical processes that have acted upon the populations. Here, we focused on diversity at toll-like receptor (TLR) loci, which play a key role in the vertebrate innate immune system and, therefore, are expected to be under pathogen-mediated selection. We assessed TLR variation within and among 13 island populations (grouped into three archipelagos) of Berthelot's pipit, Anthus berthelotii, for which detailed population history has previously been ascertained. We also compared the variation observed with that found in its widespread sister species, the tawny pipit, Anthus campestris. We found strong evidence for positive selection at specific codons in TLR1LA, TLR3 and TLR4. Despite this, we found that at the allele frequency level, demographic history has played the major role in shaping patterns of TLR variation in Berthelot's pipit. Levels of diversity and differentiation within and across archipelagos at all TLR loci corresponded very closely with neutral microsatellite variation and with the severity of the bottlenecks that occurred during colonization. Our study shows that despite the importance of TLRs in combating pathogens, demography can be the main driver of immune gene variation within and across populations, resulting in patterns of functional variation that can persist over evolutionary timescales.

  14. Glycogen synthase kinase 3β in Toll-like receptor signaling

    PubMed Central

    Ko, Ryeojin; Lee, Soo Young

    2016-01-01

    Toll-like receptors (TLRs) play a critical role in the innate immune response against pathogens. Each TLR recognizes specific pathogen-associated molecular patterns, after which they activate the adaptor protein MyD88 or TRIF-assembled signaling complex to produce immune mediators, including inflammatory cytokines and type I IFNs. Although the activation of TLR is important for host defense, its uncontrolled activation can damage the host. During the past decade, numerous studies have demonstrated that GSK3β is a key regulator of inflammatory cytokine production in MyD88-mediated TLR signaling via TLR2 and TLR4. Recently, GSK3β has also been implicated in the TRIF-dependent signaling pathway via TLR3. In this review, we describe current advances on the regulatory role of GSK3β in immune responses associated with various TLRs. A better understanding of the role of GSK3β in TLR signaling might lead to more effective anti-inflammatory interventions. [BMB Reports 2016; 49(6): 305-310] PMID:26996345

  15. The role of toll-like receptor-4 in the development of multi-organ failure following traumatic haemorrhagic shock and resuscitation.

    PubMed

    McGhan, Lee J; Jaroszewski, Dawn E

    2012-02-01

    Haemorrhagic shock and resuscitation (HS/R) following major trauma results in a global ischaemia and reperfusion injury that may lead to multiple organ dysfunction syndrome (MODS). Systemic activation of the immune system is fundamental to the development of MODS in this context, and shares many features in common with the systemic inflammatory response syndrome (SIRS) that complicates sepsis. An important advancement in the understanding of the innate response to infection involved the identification of mammalian toll-like receptors (TLRs) expressed on cells of the immune system. Ten TLR homologues have been identified in humans and toll-like receptor-4 (TLR4) has been studied most intensively. Initially found to recognise bacterial lipopolysaccharide (LPS), it has also recently been discovered that TLR4 is capable of activation by endogenous 'danger signal' molecules released following cellular injury; this has since implicated TLR4 in several non-infectious pathophysiologic processes, including HS/R. The exact events leading to multi-organ dysfunction following HS/R have not yet been clearly defined, although TLR4 is believed to play a central role as has been shown to be expressed at sites including the liver, lungs and myocardium following HS/R. Multi-organ dysfunction syndrome remains an important cause of morbidity and mortality in trauma patients, and current therapy is based on supportive care. Understanding the pathophysiology of HS/R will allow for the development of targeted therapeutic strategies aimed at minimising organ dysfunction and improving patient outcomes following traumatic haemorrhage. A review of the pathogenesis of haemorrhagic shock is presented, and the complex, yet critical role of TLR4 as both a key mediator and therapeutic target is discussed.

  16. Lactobacillus casei Zhang modulate cytokine and toll-like receptor expression and beneficially regulate poly I:C-induced immune responses in RAW264.7 macrophages.

    PubMed

    Wang, Yuzhen; Xie, Jiming; Wang, Na; Li, Yunxu; Sun, Xiaolin; Zhang, Yong; Zhang, Heping

    2013-01-01

    Lactobacilli are frequently used as probiotics due to their beneficial effects on health. Lactobacillus casei Zhang (LcZ), which has favorable probiotic properties, was first isolated from koumiss. In this study, the immunomodulating effects of LcZ on cytokine and toll-like receptor expression in RAW264.7 macrophages was assessed and it was found that live LcZ promotes production of nitric oxide (NO), tumor necrosis factor (TNF)-α, interleukin (IL)-6 and interferon (IFN)-β. Transcription of inducible nitric oxide synthase (iNOS) was also enhanced by viable LcZ. The immunostimulating effects of live LcZ are significantly attenuated in heat-killed LcZ. Live LcZ promotes TLR2 mRNA transcription, whereas heat-killed LcZ enhances transcription of TLR2, TLR3, TLR4 and TLR9. Furthermore, live LcZ significantly suppresses polyinosinic:polycytidylic acid (poly I:C)-stimulated NO, iNOS and TNF-α expression while enhancing expression of IFN-β. It was also found that poly I:C-induced interferon regulatory factor 3 (IRF-3) reporter gene activity was significantly up-regulated by live LcZ. These results suggest that LcZ keeps the innate immune system alert by increasing transcription of Toll-like receptors and enhancing production of pro-inflammatory mediators and type I IFN in macrophages. The synergistic effect of live LcZ with poly I:C on IFN-β expression is associated with increased activity of IRF-3. LcZ has the potential to be used as an adjuvant against viral infections. PMID:23350674

  17. Relative Expression of Toll-Like Receptors 2 and 7 mRNA in Peripheral Blood of Patients With Hepatitis C

    PubMed Central

    Dehghan-Manshadi, Mahdi; Hadinedoushan, Hossein; Amirbaigy, Mohammad Kazem; Zare, Fateme; Eslami, Gilda; Mirghanizade-Bafghi, Seyyed Ali; Akhondi-Meybodi, Mohsen

    2015-01-01

    Background: Hepatitis C virus (HCV) is an important human pathogen affecting an estimated 120 – 170 million individuals in the world. Toll-Like receptors (TLRs) are pattern-recognition receptors that recognize pathogen-associated molecular patterns, and stimulate immune responses. Objectives: The aim of this study was to determine the mRNA expression level of TLR2 and TLR7 in HCV-infected patients in comparison with normal controls. Patients and Methods: Nineteen consecutive patients with HCV infection and nineteen sex and age-matched healthy controls were studied in a case-controlled research. Results: Our results showed that the expressions of TLR7 in HCV infected samples were significantly increased in comparison those of the controls (P = 0.02), while the expression of TLR2 was similar between the case and the control group (P = 0.8). There were no associations between the expression levels of TLR2 and TLR7 with HCV viral load and HCV genotypes. Also, there was no association between viral load and genotypes of the virus. Conclusions: Our findings showed that HCV infection could lead to increased expression level of TLR7 mRNA in peripheral blood cells of HCV infected samples. The viral load and genotypes of HCV did not affect the mRNA expression levels of TLR2 and TLR7. PMID:26834788

  18. Presence of toll like receptor-2 in spleen, lymph node and thymus of Swiss albino mice and its modulation by Staphylococcus aureus and bacterial lipopolysaccharide. .

    PubMed

    Ghosh, Chandrayee; Prakash, Nune Ravi; Manna, Sunil Kumar; Bishayi, Biswadev

    2015-02-01

    Toll-like receptors (TLR) are a family of pattern recognition receptors identifying pathogen associated molecular patterns (PAMPs). They play a critical role in the innate immune response during the initial interaction between the infecting microorganism and phagocytic cells. Here, we verified the presence of TLR-2 in spleen, lymph node and thymus of Swiss albino mice and their modulation after infection with Staphylococcus aureus and Lipopolysaccharide (LPS) challenge. It was seen that TLR-2 gene transcribed to its respective mRNA on S. aureus infection, in thymus, spleen and lymph node of mice but their levels and mode of expression varied. When challenged with LPS no prominent changes in the expression of TLR-2 receptor was observed but its expression increased gradually with time in the thymus, spleen and lymph node of S. aureus infected mice. TLR-2 expression was also found enhanced in infected splenic macrophages. By studying the serum cytokine profile the functionality of the receptor was measured. The results indicate the presence of TLR-2 in thymus, spleen and lymph node of Swiss albino strain of mice and that they are modulated by S. aureus.

  19. Nerve Growth Factor Is Regulated by Toll-Like Receptor 2 in Human Intervertebral Discs.

    PubMed

    Krock, Emerson; Currie, J Brooke; Weber, Michael H; Ouellet, Jean A; Stone, Laura S; Rosenzweig, Derek H; Haglund, Lisbet

    2016-02-12

    Nerve growth factor (NGF) contributes to the development of chronic pain associated with degenerative connective tissue pathologies, such as intervertebral disc degeneration and osteoarthritis. However, surprisingly little is known about the regulation of NGF in these conditions. Toll-like receptors (TLR) are pattern recognition receptors classically associated with innate immunity but more recently were found to be activated by endogenous alarmins such as fragmented extracellular matrix proteins found in degenerating discs or cartilage. In this study we investigated if TLR activation regulates NGF and which signaling mechanisms control this response in intervertebral discs. TLR2 agonists, TLR4 agonists, or IL-1β (control) treatment increased NGF, brain-derived neurotrophic factor (BDNF), and IL-1β gene expression in human disc cells isolated from healthy, pain-free organ donors. However, only TLR2 activation or IL-1β treatment increased NGF protein secretion. TLR2 activation increased p38, ERK1/2, and p65 activity and increased p65 translocation to the cell nucleus. JNK activity was not affected by TLR2 activation. Inhibition of NF-κB, and to a lesser extent p38, but not ERK1/2 activity, blocked TLR2-driven NGF up-regulation at both the transcript and protein levels. These results provide a novel mechanism of NGF regulation in the intervertebral disc and potentially other pathogenic connective tissues. TLR2 and NF-κB signaling are known to increase cytokines and proteases, which accelerate matrix degradation. Therefore, TLR2 or NF-κB inhibition may both attenuate chronic pain and slow the degenerative progress in vivo. PMID:26668319

  20. Toll-like receptor 4 promotes fibrosis in bleomycin-induced lung injury in mice.

    PubMed

    Li, X X; Jiang, D Y; Huang, X X; Guo, S L; Yuan, W; Dai, H P

    2015-12-21

    The specific role of Toll-like receptor 4 (TLR4) in bleomycin-induced lung fibrosis of mice, a model of human idiopathic pulmonary fibrosis, has not been characterized. We injected bleomycin intratracheally into TLR4 knockout (TLR4(-/-)) and wild-type (WT) mice. Twenty-one days after injection, mice were sacrificed and their lungs were harvested for pathological, hydroxyproline, mRNA expression, and collagen I analyses. Body weight changes and mortality were observed. Light microscopy showed that lung fibrosis was minimal in TLR4(-/-) compared to that in WT mice on day 21 after bleomycin instillation. The Ashcroft score was significantly lower in TLR4(-/-) than in WT mice (3.667 ± 0.730 vs 4.945 ± 0.880, P < 0.05). Hydroxyproline content was significantly lower in TLR4(-/-) than in WT mice on day 21 after bleomycin injection (0.281 ± 0.022 vs 0.371 ± 0.047, P < 0.05). Compared to WT mice, bleomycin-treated TLR4(-/-) mice expressed significantly lower type I collagen mRNA levels (mesenchymal marker; 11.069 ± 2.627 vs 4.589 ± 1.440, P < 0.05). Collagen I was significantly lower in TLR4(-/-) than in WT mice (0.838 ± 0.352 vs 2.427 ± 0.551, P < 0.05). Bleomycin-treated TLR4(-/-) mice had a significantly lower mortality rate on day 21 than WT mice (33 vs 75%, P < 0.05). Body weight reduction was lower in TLR4(-/-) mice than in WT mice; this difference was not statistically significant (-3.735 ± 5.276 vs -6.698 ± 3.218, P > 0.05). Thus, bleomycin-induced pulmonary fibrosis is TLR4-dependent and TLR4 promoted fibrosis in bleomycin-challenged mice.

  1. Local interleukin-1-driven joint pathology is dependent on toll-like receptor 4 activation.

    PubMed

    Abdollahi-Roodsaz, Shahla; Joosten, Leo A B; Koenders, Marije I; van den Brand, Ben T; van de Loo, Fons A J; van den Berg, Wim B

    2009-11-01

    Toll-like receptors (TLRs) may contribute to the pathogenesis of chronic inflammatory destructive diseases through the recognition of endogenous ligands produced on either inflammation or degeneration of the extracellular matrix. The presence of endogenous TLR agonists has been reported in rheumatoid joints. In the present study, we investigated the significance of TLR2 and TLR4 activation by locally- produced endogenous ligands in the severity of joint inflammation and destruction. Local joint pathology independent of systemic immune activation was induced by overexpression of interleukin (IL)-1 and TNF in naive joints using adenoviral gene transfer. Here, we report that at certain doses, IL-1-induced local joint inflammation, cartilage proteoglycan depletion, and bone erosion are dependent on TLR4 activation, whereas TLR2 activation is not significantly involved. In comparison, tumor necrosis factor alpha-driven joint pathology seemed to be less dependent on TLR2 and TLR4. The severity of IL-1-induced bone erosion and irreversible cartilage destruction was markedly reduced in TLR4(-/-) mice, even though the degree of inflammation was similar, suggesting uncoupled processes. Furthermore, the expression of cathepsin K, a marker for osteoclast activity, induced by IL-1beta was dependent on TLR4. Overexpression of IL-1beta in the joint as well as ex vivo IL-1 stimulation of patellae provoked the release of endogenous TLR4 agonists capable of inducing TLR4-mediated cytokine production. These data emphasize the potential relevance of TLR4 activation in rheumatoid arthritis, particularly with respect to IL-1-mediated joint pathology.

  2. Toll-like receptor-4 pathway is required for the pathogenesis of human chronic endometritis

    PubMed Central

    JU, JINFEN; LI, LIANGPENG; XIE, JINGYAN; WU, YAN; WU, XI; LI, WEIHON

    2014-01-01

    Toll-like receptor (TLR) signal transduction is a central component of the primary innate immune response to pathogenic challenge. TLR4, a member of the TLR family, is highly expressed in the endometrial cells of the uterus and could thus be a key link between human chronic endometritis (CE) and the immune system. However, the exact biological function of TLR4 in human CE remains largely unexplored. The present study aimed to examine the role of TLR4 in human CE. A comprehensive expression and activation analysis of TLR4 in the endometrial cells of the uterus from patients with human CE (n=25) and normal endometrial (NE) tissue (n=15) was performed. Western blot analyses demonstrated that compared with NE, the protein expression TLR4 markedly increased in human CE. Endometrial tissue scrapings were also used for total RNA extraction and were transcribed and amplified by reverse transcription quantitative polymerase chain reaction. The results showed that significant upregulation of tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β), and downregulation of IL-10 mRNA was observed in CE compared with the NE group. Furthermore, the protein of the signaling adapter myeloid differentiation factor-88 and the accessory molecules (TNF receptor associated factor 6 and transforming growth factor-β-activated kinase 1) were also detected in all the assayed tissues. Of note, differential expression (CE versus NE) was observed by immunoblotting at each level of the nuclear factor-κB signaling cascade, including inhibitor κBα and P65 (all P<0.05). The altered TLR4 and its corresponding downstream signaling molecules in CE cells may be of relevance for the progression of the human CE. These findings indicate that the evaluation of expression patterns of TLR4 holds promise for the treatment of human CE. PMID:25371751

  3. Toll-like receptor-4 pathway is required for the pathogenesis of human chronic endometritis.

    PubMed

    Ju, Jinfen; Li, Liangpeng; Xie, Jingyan; Wu, Yan; Wu, Xi; Li, Weihon

    2014-12-01

    Toll-like receptor (TLR) signal transduction is a central component of the primary innate immune response to pathogenic challenge. TLR4, a member of the TLR family, is highly expressed in the endometrial cells of the uterus and could thus be a key link between human chronic endometritis (CE) and the immune system. However, the exact biological function of TLR4 in human CE remains largely unexplored. The present study aimed to examine the role of TLR4 in human CE. A comprehensive expression and activation analysis of TLR4 in the endometrial cells of the uterus from patients with human CE (n=25) and normal endometrial (NE) tissue (n=15) was performed. Western blot analyses demonstrated that compared with NE, the protein expression TLR4 markedly increased in human CE. Endometrial tissue scrapings were also used for total RNA extraction and were transcribed and amplified by reverse transcription quantitative polymerase chain reaction. The results showed that significant upregulation of tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β), and downregulation of IL-10 mRNA was observed in CE compared with the NE group. Furthermore, the protein of the signaling adapter myeloid differentiation factor-88 and the accessory molecules (TNF receptor associated factor 6 and transforming growth factor-β-activated kinase 1) were also detected in all the assayed tissues. Of note, differential expression (CE versus NE) was observed by immunoblotting at each level of the nuclear factor-κB signaling cascade, including inhibitor κBα and P65 (all P<0.05). The altered TLR4 and its corresponding downstream signaling molecules in CE cells may be of relevance for the progression of the human CE. These findings indicate that the evaluation of expression patterns of TLR4 holds promise for the treatment of human CE. PMID:25371751

  4. 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

  5. Role of gut microbiota and Toll-like receptors in nonalcoholic fatty liver disease

    PubMed Central

    Miura, Kouichi; Ohnishi, Hirohide

    2014-01-01

    Emerging data have shown a close association between compositional changes in gut microbiota and the development of nonalcoholic fatty liver disease (NAFLD). The change in gut microbiota may alter nutritional absorption and storage. In addition, gut microbiota are a source of Toll-like receptor (TLR) ligands, and their compositional change can also increase the amount of TLR ligands delivered to the liver. TLR ligands can stimulate liver cells to produce proinflammatory cytokines. Therefore, the gut-liver axis has attracted much interest, particularly regarding the pathogenesis of NAFLD. The abundance of the major gut microbiota, including Firmicutes and Bacteroidetes, has been considered a potential underlying mechanism of obesity and NAFLD, but the role of these microbiota in NAFLD remains unknown. Several reports have demonstrated that certain gut microbiota are associated with the development of obesity and NAFLD. For instance, a decrease in Akkermansia muciniphila causes a thinner intestinal mucus layer and promotes gut permeability, which allows the leakage of bacterial components. Interventions to increase Akkermansia muciniphila improve the metabolic parameters in obesity and NAFLD. In children, the levels of Escherichia were significantly increased in nonalcoholic steatohepatitis (NASH) compared with those in obese control. Escherichia can produce ethanol, which promotes gut permeability. Thus, normalization of gut microbiota using probiotics or prebiotics is a promising treatment option for NAFLD. In addition, TLR signaling in the liver is activated, and its downstream molecules, such as proinflammatory cytokines, are increased in NAFLD. To data, TLR2, TLR4, TLR5, and TLR9 have been shown to be associated with the pathogenesis of NAFLD. Therefore, gut microbiota and TLRs are targets for NAFLD treatment. PMID:24966608

  6. Borrelia garinii Induces CXCL13 Production in Human Monocytes through Toll-Like Receptor 2▿

    PubMed Central

    Rupprecht, Tobias A.; Kirschning, Carsten J.; Popp, Bernadette; Kastenbauer, Stefan; Fingerle, Volker; Pfister, Hans-Walter; Koedel, Uwe

    2007-01-01

    Recent studies have suggested an important role for the B-cell-attracting chemokine CXCL13 in the B-cell-dominated cerebrospinal fluid (CSF) infiltrate in patients with neuroborreliosis (NB). High levels of CXCL13 were present in the CSF of NB patients. It has not been clear, however, whether high CSF CXCL13 titers are specific for NB or are a characteristic of other spirochetal diseases as well. Furthermore, the mechanisms leading to the observed CXCL13 expression have not been identified yet. Here we describe similarly elevated CSF CXCL13 levels in patients with neurosyphilis, while pneumococcal meningitis patient CSF do not have high CXCL13 levels. In parallel, challenge of human monocytes in vitro with two of the spirochetal causative organisms, Borrelia garinii (the Borrelia species most frequently found in NB patients) and Treponema pallidum, but not challenge with pneumococci, induced CXCL13 release. This finding implies that a common spirochetal motif is a CXCL13 inducer. Accordingly, we found that the lipid moiety N-palmitoyl-S-(bis[palmitoyloxy]propyl)cystein (Pam3C) (three palmitoyl residues bound to N-terminal cysteine) of the spirochetal lipoproteins is critical for the CXCL13 induction in monocytes. As the Pam3C motif is known to signal via Toll-like receptor 2 (TLR2) and an anti-TLR2 monoclonal antibody blocked CXCL13 production of human monocytes incubated with B. garinii, this suggests that TLR2 is a major mediator of Borrelia-induced secretion of CXCL13 from human monocytes. PMID:17562761

  7. Agonists of Toll-like receptor 9 containing synthetic dinucleotide motifs.

    PubMed

    Yu, Dong; Putta, Mallikarjuna R; Bhagat, Lakshmi; Li, Yukui; Zhu, Fugang; Wang, Daqing; Tang, Jimmy X; Kandimalla, Ekambar R; Agrawal, Sudhir

    2007-12-13

    Oligodeoxynucleotides (ODNs) containing unmethylated CpG motifs activate Toll-like receptor 9 (TLR9). Our previous studies have shown that ODNs containing two 5'-ends are more immunostimulatory than those with one 5'-end. In the present study, to understand the role of functional groups in TLR9 recognition and subsequent immune response, we substituted C or G of a CpG dinucleotide with 5-OH-dC, 5-propyne-dC, furano-dT, 1-(2'-deoxy-beta- d-ribofuranosyl)-2-oxo-7-deaza-8-methyl-purine, dF, 4-thio-dU, N(3)-Me-dC, N (4)-Et-dC, Psi-iso-dC, and arabinoC or 7-deaza-dG, 7-deaza-8-aza-dG, 9-deaza-dG, N(1)-Me-dG, N(2)-Me-dG, 6-Thio-dG, dI, 8-OMe-dG, 8-O-allyl-dG, and arabinoG in ODN containing two 5'-ends. Agonists of TLR9 containing cytosine or guanine modification showed activity in HEK293 cells expressing TLR9, mouse spleen, and human cell-based assays and in vivo in mice. The results presented here provide insight into which specific chemical modifications at C or G of the CpG motif are recognized by TLR9 and the ability to modulate immune responses substituting natural C or G in immune modulatory oligonucleotides. PMID:17988082

  8. Practical techniques for detection of Toll-like receptor-4 in the human intestine.

    PubMed

    Ungaro, Ryan; Abreu, Maria T; Fukata, Masayuki

    2009-01-01

    The human intestine has evolved in the presence of a diverse array of luminal microorganisms. In order to maintain intestinal homeostasis, mucosal immune responses to theses microorganisms must be tightly regulated. The intestine needs to be able to respond to pathogenic organisms while at the same time maintain tolerance to normal commensal flora. Toll-like receptors (TLRs) play an important role in this delicate balance. TLRs are transmembrane noncatalytic receptor proteins that induce activation of innate and adaptive immune responses to microorganisms by recognizing structurally conserved molecular patterns of microbes. Expression of TLRs by intestinal epithelial cell is normally down-regulated to maintain immune tolerance to the luminal microorganisms.One of the challenges of TLR research in the human intestine is that it is difficult for many experimental methods to detect very low expression of TLRs within the intestinal mucosa. Quantitative methods such as PCR are limited in their ability to detect TLR expression by specific cell types within a tissue sample, which can be important when studying the contribution of TLR signaling to pathological conditions. In this regard, immunohistochemistry (IHC) is advantageous in that one can visualize the distribution and localization of target proteins within both normal and pathologic parts of a given tissue sample. We found that a subset of human colorectal cancers over-express TLR4 by means of immunofluorescence (IF) and IHC methods. Localization of TLR4 within cancer tissue often appears to be patchy, making IHC an appropriate way to examine these changes. We will describe our current techniques to detect TLR4 in paraffin-embedded human large intestine sections. Establishing a practical IHC technique that may provide consistent results between laboratories will significantly enhance understanding of the role of TLRs in human intestinal health and disease.

  9. Toll-like receptor ligand activation of murine bone marrow-derived dendritic cells

    PubMed Central

    Dearman, Rebecca J; Cumberbatch, Marie; Maxwell, Gavin; Basketter, David A; Kimber, Ian

    2009-01-01

    Dendritic cells (DCs) are required for the initiation of primary immune responses. The pattern of Toll-like receptor (TLR) expression on various subsets of these cells has been shown to differ, suggestive of distinct roles in influencing immune responses. We have examined here the responses of immature DCs derived from murine bone marrow (BMDCs) to a range of TLR ligands. BMDCs cultured for 6 days in the presence of granulocyte–macrophage colony-stimulating factor were stimulated for 24 hr with ligands to TLR1-2 [Pam3Cys-Ser-(Lys)4 (PAM)], TLR2-6 (macrophage-activating lipopeptide-2 (MALP-2); zymosan or peptidoglycan (PG)], TLR3 (polyinosinic-polycytidylic acid), TLR4 [lipopolysaccharide R515 (LPS)], TLR5 (flagellin), TLR7 (polyuridylic acid) and TLR9 [CpG ODN2395 (CpG)]. DC activation was monitored using membrane marker expression and analysis of culture supernatants for cytokine/chemokine release. Ligands to TLR3 and TLR7 failed to activate BMDCs. All other TLR ligands caused elevated expression of membrane markers. PAM, MALP-2 and LPS induced high-level expression of proinflammatory cytokines and chemokines. Treatment with CpG was associated with a preferential type 1 cytokine and chemokine profile. Zymosan and PG were proinflammatory but also skewed towards a type 2 pattern of cytokines and chemokines. In contrast, flagellin did not cause marked secretion by BMDCs of cytokines or chemokines. These data for BMDCs are largely consistent with the reported TLR repertoire of freshly isolated murine Langerhans cells. In addition, murine BMDCs show selective responses to TLR ligands with respect to general activation, with differentiated cytokine patterns suggestive of potential priming for divergent immune responses. PMID:18778283

  10. Targeting Toll-like receptor 4 prevents cobalt-mediated inflammation.

    PubMed

    Lawrence, Helen; Mawdesley, Amy Elizabeth; Holland, James Patrick; Kirby, John Andrew; Deehan, David John; Tyson-Capper, Alison Jane

    2016-02-16

    Cobalt-chrome alloy is a widely used biomaterial in joint replacements, dental implants and spinal rods. Although it is an effective and biocompatible material, adverse reactions to metal debris (ARMD) have arisen in a minority of patients, particularly in those with metal-on-metal bearing hip replacements. There is currently no treatment for ARMD and once progressive, early revision surgery of the implant is necessary. Therapeutic agents to prevent, halt or reverse ARMD would therefore be advantageous. Cobalt ions activate Toll-like receptor 4 (TLR4), an innate immune receptor responsible for inflammatory responses to bacterial lipopolysaccharide (LPS) resulting in the production of pro-inflammatory cytokines and chemokines. We hypothesised that anti-TLR4 neutralising antibodies, reported to inhibit TLR4-mediated inflammation, could prevent the inflammatory response to cobalt ions in an in vitro macrophage cell culture model. This study shows that a monoclonal anti-TLR4 antibody inhibited cobalt-mediated increases in pro-inflammatory IL8, CCL20 and IL1A expression, as well as IL-8 secretion. In contrast, a polyclonal antibody did not prevent the effect of cobalt ions on either IL-8 or IL1A expression, although it did have a small effect on the CCL20 response. Interestingly, both antibodies inhibited cobalt-mediated neutrophil migration although the greater effect was observed with the monoclonal antibody. In summary our data shows that a monoclonal anti-TLR4 antibody can inhibit cobalt-mediated inflammatory responses while a polyclonal antibody only inhibits the effect of specific cytokines. Anti-TLR4 antibodies have therapeutic potential in ARMD although careful antibody design is required to ensure that the LPS response is preserved. PMID:26840091

  11. Expression of toll-like receptors on human rectal adenocarcinoma cells.

    PubMed

    Tchórzewski, Marcin; Lewkowicz, Przemysław; Dziki, Adam; Tchórzewski, Henryk

    2014-06-01

    The innate immune system uses Toll-like receptors (TLR) to detect the presence of pathogen patterns thus allowing for rapid host defense responses. Stimulation of TLR results in inflammatory response and regulatory cytokine production affecting acquired immunity. The aim of the study was an evaluation of TLR2 and TLR4 expression on the surface of human colon cancer cells in primary culture with or without autologous peripheral blood mononuclear cells. Surgical specimens of colon cancer were processed to obtain cancer cells. Cancer cells separation was conducted first by mechanical tissue disintegration and than by gradient centrifugation to obtain 95 % cell confluence. By staining the isolated cells the pathologist determined them as adenocarcinoma. Colon cancer cells were then co-cultured in 24 h culture alone or together with autologous lymphocytes. Reverse-transcription polymerase chain reaction was performed for detection of TLR2 and TLR4 mRNA in colon cancer and normal colon epithelial cells using commercially available primers. Resting as well as phytohemagglutinin or lipopolysaccharide (LPS) stimulated cells were tested. Receptor proteins on cancer cells were examined by immunohistochemistry. TLR4 mRNA was detected in cancer cells. Autologous lymphocytes do not exert any effect on these receptors expression. TLR4 mRNA expression was not observed in normal colon epithelial cells. TLR2 mRNA was present on LPS stimulated cancer cells as well as on resting and stimulated lymphocytes. Expression of TLR2 and TLR4 receptor proteins on colon cancer cells were confirmed by immunohistochemistry. TLR4 may be responsible for uncontrolled tumor growth under LPS stimulation in human colon environment.

  12. 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. PMID:26383860

  13. 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

  14. 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

  15. Toll-like receptor 2-mediated alternative activation of microglia is protective after spinal cord injury.

    PubMed

    Stirling, David P; Cummins, Karen; Mishra, Manoj; Teo, Wulin; Yong, V Wee; Stys, Peter

    2014-03-01

    Improving neurological outcome after spinal cord injury is a major clinical challenge because axons, once severed, do not regenerate but 'dieback' from the lesion site. Although microglia, the immunocompetent cells of the brain and spinal cord respond rapidly to spinal cord injury, their role in subsequent injury or repair remains unclear. To assess the role of microglia in spinal cord white matter injury we used time-lapse two-photon and spectral confocal imaging of green fluorescent protein-labelled microglia, yellow fluorescent protein-labelled axons, and Nile Red-labelled myelin of living murine spinal cord and revealed dynamic changes in white matter elements after laser-induced spinal cord injury in real time. Importantly, our model of acute axonal injury closely mimics the axonopathy described in well-characterized clinically relevant models of spinal cord injury including contusive-, compressive- and transection-based models. Time-lapse recordings revealed that microglia were associated with some acute pathophysiological changes in axons and myelin acutely after laser-induced spinal cord injury. These pathophysiological changes included myelin and axonal spheroid formation, spectral shifts in Nile Red emission spectra in axonal endbulbs detected with spectral microscopy, and 'bystander' degeneration of axons that survived the initial injury, but then succumbed to secondary degeneration. Surprisingly, modulation of microglial-mediated release of neurotoxic molecules failed to protect axons and myelin. In contrast, sterile stimulation of microglia with the specific toll-like receptor 2 agonist Pam2CSK4 robustly increased the microglial response to ablation, reduced secondary degeneration of central myelinated fibres, and induced an alternative (mixed M1:M2) microglial activation profile. Conversely, Tlr2 knock out: Thy1 yellow fluorescent protein double transgenic mice experienced greater axonal dieback than littermate controls. Thus, promoting an alternative

  16. Differential immunomodulatory activity of tumor cell death induced by cancer therapeutic toll-like receptor ligands.

    PubMed

    Klein, Johanna C; Wild, Clarissa A; Lang, Stephan; Brandau, Sven

    2016-06-01

    Synthetic toll-like receptor (TLR) ligands stimulate defined immune cell subsets and are currently tested as novel immunotherapeutic agents against cancer with, however, varying clinical efficacy. Recent data showed the expression of TLR receptors also on tumor cells. In this study we investigated immunological events associated with the induction of tumor cell death by poly(I:C) and imiquimod. A human head and neck squamous cell carcinoma (HNSCC) cell line was exposed to poly(I:C) and imiquimod, which were delivered exogenously via culture medium or via electroporation. Cell death and cell biological consequences thereof were analyzed. For in vivo analyses, a human xenograft and a syngeneic immunocompetent mouse model were used. Poly(I:C) induced cell death only if delivered by electroporation into the cytosol. Cell death induced by poly(I:C) resulted in cytokine release and activation of monocytes in vitro. Monocytes activated by the supernatant of cancer cells previously exposed to poly(I:C) recruited significantly more Th1 cells than monocytes exposed to control supernatants. If delivered exogenously, imiquimod also induced tumor cell death and some release of interleukin-6, but cell death was not associated with release of Th1 cytokines, interferons, monocyte activation and Th1 recruitment. Interestingly, intratumoral injection of poly(I:C) triggered tumor cell death in tumor-bearing mice and reduced tumor growth independent of TLR signaling on host cells. Imiquimod did not affect tumor size. Our data suggest that common cancer therapeutic RNA compounds can induce functionally diverse types of cell death in tumor cells with implications for the use of TLR ligands in cancer immunotherapy. PMID:27034235

  17. Dynamic Evolution of Toll-Like Receptor Multigene Families in Echinoderms

    PubMed Central

    Buckley, Katherine M.; Rast, Jonathan P.

    2012-01-01

    The genome sequence of the purple sea urchin, Strongylocentrotus purpuratus, a large and long-lived invertebrate, provides a new perspective on animal immunity. Analysis of this genome uncovered a highly complex immune system in which the gene families that encode homologs of the pattern recognition receptors that form the core of vertebrate innate immunity are encoded in large multigene families. The sea urchin genome contains 253 Toll-like receptor (TLR) sequences, more than 200 Nod-like receptors and 1095 scavenger receptor cysteine-rich domains, a 10-fold expansion relative to vertebrates. Given their stereotypic protein structure and simple intron-exon architecture, the TLRs are the most tractable of these families for more detailed analysis. A role for these receptors in immune defense is suggested by their similarity to TLRs in other organisms, sequence diversity, and expression in immunologically active tissues, including phagocytes. The complexity of the sea urchin TLR multigene families is largely derived from expansions independent of those in vertebrates and protostomes, although a small family of TLRs with structure similar to that of Drosophila Toll can be traced to an ancient eumetazoan ancestor. Several other echinoderm sequences are now available, including Lytechinus variegatus, as well as partial sequences from two other sea urchin species. Here, we present an analysis of the invertebrate deuterostome TLRs with emphasis on the echinoderms. Representatives of most of the S. purpuratus TLR subfamilies and homologs of the mccTLR sequences are found in L. variegatus, although the L. variegatus TLR gene family is notably smaller (68 TLR sequences). The phylogeny of these genes within sea urchins highlights lineage-specific expansions at higher resolution than is evident at the phylum level. These analyses identify quickly evolving TLR subfamilies that are likely to have novel immune recognition functions and other, more stable, subfamilies that may

  18. Toll-Like Receptors on Human Mesenchymal Stem Cells Drive their Migration and Immunomodulating Responses

    PubMed Central

    Tomchuck, Suzanne L.; Zwezdaryk, Kevin J.; Coffelt, Seth B.; Waterman, Ruth S.; Danka, Elizabeth S.; Scandurro, Aline B.

    2009-01-01

    Adult human bone marrow-derived mesenchymal stem cells (hMSCs) are under study as therapeutic delivery agents that assist in the repair of damaged tissues. To achieve the desired clinical outcomes for this strategy requires a better understanding of the mechanisms that drive the recruitment, migration and engraftment of hMSCs to the targeted tissues. It is known that hMSCs are recruited to sites of stress or inflammation to fulfill their repair function. It is recognized that toll-like receptors (TLRs) mediate stress responses of other bone marrow-derived cells. This study explored the role of TLRs in mediating stress responses of hMSCs. Accordingly, the presence of TLRs in hMSCs was established initially by RT-PCR assays. Flow cytometry and fluorescence immunocytochemical analyses confirmed these findings. The stimulation of hMSCs with TLR agonists led to the activation of downstream signaling pathways, including NF-κB, AKT and MAPK. Consequently, activation of these pathways triggered the induction and secretion of cytokines, chemokines and related TLR gene products as established from cDNA array, immunoassay and cytokine antibody array analyses. Interestingly, the unique patterns of affected genes, cytokines and chemokines measured, identify these receptors as critical players in the clinically established immunomodulation, observed for hMSCs. Lastly, hMSCs migration was promoted by TLR ligand exposure as demonstrated by transwell migration assays. Conversely, disruption of TLRs by neutralizing TLR antibodies compromised hMSCs migration. This study defines a novel TLR-driven stress and immune modulating response for hMSCs that is critical to consider in the design of stem cell-based therapies. PMID:17916800

  19. The physiological regulation of toll-like receptor expression and function in humans

    PubMed Central

    Lancaster, Graeme I; Khan, Qamar; Drysdale, Pam; Wallace, Fiona; Jeukendrup, Asker E; Drayson, Mark T; Gleeson, Michael

    2005-01-01

    Eleven mammalian toll-like receptors (TLRs 1–11) have been identified to date and are known to play a crucial role in the regulation of immune responses; however, the factors that regulate TLR expression and function in vivo are poorly understood. Therefore, in the present study, we investigated the physiological regulation of TLR expression and function in humans. To examine the influence of diurnal rhythmicity on TLR expression and function, peripheral venous blood samples were collected from healthy volunteers (n = 8) at time points coinciding with the peak and nadir in the endogenous circulating cortisol concentration. While no diurnal rhythmicity in the expression of TLRs 1, 2, 4 or 9 was observed, the upregulation of costimulatory (CD80 and CD86) and antigen-presenting (MHC class II) molecules on CD14+ monocytes following activation with specific TLR ligands was greater (P < 0.05) in samples obtained in the evening compared with the morning. To examine the influence of physical stress on TLR expression and function, peripheral venous blood samples were collected from healthy volunteers (n = 11) at rest and following 1.5 h of strenuous exercise in the heat (34°C). Strenuous exercise resulted in a decrease (P < 0.005) in the expression of TLRs 1, 2 and 4 on CD14+ monocytes. Furthermore, the upregulation of CD80, CD86, MHC class II and interleukin-6 by CD14+ monocytes following activation with specific TLR ligands was decreased (P < 0.05) in samples obtained following exercise compared with at rest. These results demonstrate that TLR function is subject to modulation under physiological conditions in vivo and provide evidence for the role of immunomodulatory hormones in the regulation of TLR function. PMID:15661814

  20. Neuroprotection of donepezil against morphine-induced apoptosis is mediated through Toll-like receptors.

    PubMed

    Shafie, Alireza; Moradi, Farshid; Izadpanah, Esmael; Mokarizadeh, Aram; Moloudi, Mohammad Raman; Nikzaban, Mehrnoush; Hassanzadeh, Kambiz

    2015-10-01

    Previously, we had shown that donepezil provides anti-apoptotic effects associated with the prevention of morphine tolerance to the analgesic effect. In this regard, the present study aimed to evaluate the molecular mechanisms involved in this effect considering the possible role of Toll-like receptor (TLR) 2,4, and the balance between pre-apoptotic and anti-apoptotic Bcl family proteins. To this end, male Wistar rats received daily morphine in combination with either normal saline or donepezil (0.5, 1, or 1.5 mg/kg, ip). The analgesic effect was assessed by the plantar test apparatus. The latency was recorded when the animal responded to the light stimulus. On the 15th day, when no significant difference was observed between morphine and saline groups in terms of analgesia, the frontal cortex and lumbar spinal cord of the animals were dissected. Then, TLR2 and 4, Bcl2, and Bax mRNA fold changes were calculated using Real-time PCR method. The results indicated no significant analgesic effect in the morphine group compared with the saline treated animals after 15 days of injection, while daily co-administration of donepezil with morphine preserved significant analgesia. Moreover, Quantitative PCR showed that morphine significantly increased TLRs and Bax gene expressions and decreased the anti-apoptotic Bcl2. In contrast, donepezil prevented these morphine induced changes in the mentioned gene expressions. Taken together, the results suggest that the neuroprotective effects of donepezil in attenuating morphine-induced tolerance and apoptosis are mediated by preventing morphine-induced changes in TLR2 and 4 gene expressions.

  1. Toll-Like Receptor 4 Signaling Pathway Mediates Inhalant Organic Dust-Induced Bone Loss.

    PubMed

    Staab, Elizabeth; Thiele, Geoffrey M; Clarey, Dillon; Wyatt, Todd A; Romberger, Debra J; Wells, Adam D; Dusad, Anand; Wang, Dong; Klassen, Lynell W; Mikuls, Ted R; Duryee, Michael J; Poole, Jill A

    2016-01-01

    Agriculture workers have increased rates of airway and skeletal disease. Inhalant exposure to agricultural organic dust extract (ODE) induces bone deterioration in mice; yet, mechanisms underlying lung-bone crosstalk remain unclear. Because Toll-like receptor 2 (TLR2) and TLR4 are important in mediating the airway consequences of ODE, this study investigated their role in regulating bone responses. First, swine facility ODE stimulated wild-type (WT) bone marrow macrophages to form osteoclasts, and this finding was inhibited in TLR4 knock-out (KO), but not TLR2 KO cells. Next, using an established intranasal inhalation exposure model, WT, TLR2 KO and TLR4 KO mice were treated daily with ODE or saline for 3 weeks. ODE-induced airway neutrophil influx and cytokine/chemokine release were similarly reduced in TLR2 and TLR4 KO animals as compared to WT mice. Utilizing micro-computed tomography (CT), analysis of tibia showed loss of bone mineral density, volume and deterioration of bone micro-architecture and mechanical strength induced by ODE in WT mice were significantly reduced in TLR4 but not TLR2 KO animals. Bone marrow osteoclast precursor cell populations were analyzed by flow cytometry from exposed animals. In WT animals, exposure to inhalant ODE increased osteoclast precursor cell populations as compared to saline, an effect that was reduced in TLR4 but not TLR2 KO mice. These results show that TLR2 and TLR4 pathways mediate ODE-induced airway inflammation, but bone deterioration consequences following inhalant ODE treatment is strongly dependent upon TLR4. Thus, the TLR4 signaling pathway appears critical in regulating the lung-bone inflammatory axis to microbial component-enriched organic dust exposures. PMID:27479208

  2. Association of bovine Toll-like receptor 4 with tick infestation rates and blood histamine concentration.

    PubMed

    Zhao, G; Yu, M; Cui, Q-W; Zhou, X; Zhang, J-C; Li, H-X; Qu, K-X; Wang, G-L; Huang, B-Z

    2013-01-01

    We investigated a possible association between bovine Toll-like receptor 4 (TLR4) and resistance to tick infestation in 103 cattle, including BMY cattle (1/2 Brahman, 1/4 Murray Grey, and 1/4 Yunnan Yellow cattle), Brahman, and Red Angus grazing on improved pasture. The tick infestation weight and number of Rhipicephalus microplus and the blood histamine concentration were measured and compared with those of 32 Chinese Holsteins and 30 Simmentals. A 228-bp fragment was amplified and sequenced to analyze the polymorphisms of the TLR4 gene. After SSCP and sequencing analysis, 4 SNPs, i.e., 535(A>C), 546(T>C), 605(T>A), and 618(G>C), were identified, corresponding to GenBank accession Nos. AY297041 and NW_003104150; the latter two SNPs caused Leu→Gln and Gln→His substitutions, respectively. Genotype AA was completely predominant in the Chinese Holstein and Simmental; genotypes AA and AB were detected in Red Angus, while genotypes AA, AB, BB, and BC were detected in Brahman and in BMY cattle. A negative correlation was identified between blood histamine concentration and number of tick infestation; in BMY cattle this negative association was significant. The tick infestation in cattle with genotype BB was significantly lower than in those with genotype AA. Blood histamine concentration in cattle with genotype BB was significantly higher than in those with genotype AA. The TLR4 gene mutation could affect the blood histamine level and activate the immune reaction after tick infestation. Allele B has potential as a molecular marker for tick-resistance originated from Zebu cattle for use in cattle breeding programs. PMID:23479166

  3. Toll-Like Receptor 4 Signaling Pathway Mediates Inhalant Organic Dust-Induced Bone Loss

    PubMed Central

    Staab, Elizabeth; Thiele, Geoffrey M.; Clarey, Dillon; Wyatt, Todd A.; Romberger, Debra J.; Wells, Adam D.; Dusad, Anand; Wang, Dong; Klassen, Lynell W.; Mikuls, Ted R.; Duryee, Michael J.; Poole, Jill A.

    2016-01-01

    Agriculture workers have increased rates of airway and skeletal disease. Inhalant exposure to agricultural organic dust extract (ODE) induces bone deterioration in mice; yet, mechanisms underlying lung-bone crosstalk remain unclear. Because Toll-like receptor 2 (TLR2) and TLR4 are important in mediating the airway consequences of ODE, this study investigated their role in regulating bone responses. First, swine facility ODE stimulated wild-type (WT) bone marrow macrophages to form osteoclasts, and this finding was inhibited in TLR4 knock-out (KO), but not TLR2 KO cells. Next, using an established intranasal inhalation exposure model, WT, TLR2 KO and TLR4 KO mice were treated daily with ODE or saline for 3 weeks. ODE-induced airway neutrophil influx and cytokine/chemokine release were similarly reduced in TLR2 and TLR4 KO animals as compared to WT mice. Utilizing micro-computed tomography (CT), analysis of tibia showed loss of bone mineral density, volume and deterioration of bone micro-architecture and mechanical strength induced by ODE in WT mice were significantly reduced in TLR4 but not TLR2 KO animals. Bone marrow osteoclast precursor cell populations were analyzed by flow cytometry from exposed animals. In WT animals, exposure to inhalant ODE increased osteoclast precursor cell populations as compared to saline, an effect that was reduced in TLR4 but not TLR2 KO mice. These results show that TLR2 and TLR4 pathways mediate ODE-induced airway inflammation, but bone deterioration consequences following inhalant ODE treatment is strongly dependent upon TLR4. Thus, the TLR4 signaling pathway appears critical in regulating the lung-bone inflammatory axis to microbial component-enriched organic dust exposures. PMID:27479208

  4. Toll-like receptors are part of the innate immune defense system of sponges (demospongiae: Porifera).

    PubMed

    Wiens, Matthias; Korzhev, Michael; Perovic-Ottstadt, Sanja; Luthringer, Bérengère; Brandt, David; Klein, Stefanie; Müller, Werner E G

    2007-03-01

    During evolution and with the emergence of multicellular animals, the need arose to ward off foreign organisms that threaten the integrity of the animal body. Among many different receptors that participate in the recognition of microbial invaders, toll-like receptors (TLRs) play an essential role in mediating the innate immune response. After binding distinct microbial components, TLRs activate intracellular signaling cascades that result in an induced expression of diverse antimicrobial molecules. Because sponges (phylum Porifera) are filter feeders, they are abundantly exposed to microorganisms that represent a potential threat. Here, we describe the identification, cloning, and deduced protein sequence from 3 major elements of the poriferan innate response (to bacterial lipopeptides): the TLR, the IL-1 receptor-associated kinase-4-like protein (IRAK-4l), and a novel effector caspase from the demosponge Suberites domuncula. Each molecule shares significant sequence similarity with its homologues in higher Metazoa. Sequence homologies were found in particular within the family-specific domains toll/interleukin-1 receptor/resistance (TLR family), Ser/Thr/Tyr kinase domain (IRAK family), and CASc (caspase family). In addition, in situ hybridization and immunohistological analyses revealed an abundance of SDTLR (TLR) transcripts in epithelial layers of the sponge surface (exopinacoderm and endopinacoderm). Furthermore, it is shown that both SDTLR and SDIRAK-4 like (IRAK) are expressed constitutively, regardless of treatment with synthetic triacyl lipopeptide Pam(3)Cys-Ser-(Lys)(4). In contrast, SDCASL (caspase) expression is highly Pam(3)Cys-Ser-(Lys)(4) inducible. However, blocking of the lipopeptide with recombinant TLR prior to its application completely prevented the induced expression of this poriferan caspase. These results underscore that the phylogenetically oldest extant metazoan phylum is provided already with the signaling pathways of the antimicrobial

  5. Immunohistochemical study of Toll-like receptors 1 and 2 expression in cutaneous lichen planus lesions.

    PubMed

    Salem, Samar Abdallah M; Abu-Zeid, Riham Mohamed; Nada, Ola Hassan

    2013-03-01

    Lichen planus (LP) is a chronic inflammatory, T cell-mediated autoimmune skin disease. Innate immunity could explain the interplay between environmental triggers and the autoimmune cascade leading to disease development. Toll-like receptors (TLRs) are important components of the innate immune system, with no previous evaluation of TLRs 1 and 2 in cutaneous LP. This work aims to investigate TLRs 1 and 2 expression in cutaneous LP. This case-control study included 30 patients with LP and 15 healthy controls. Biopsies from the patients' lesional skin and from the controls' normal skin were examined immunohistochemically for TLR 1 and 2 expression. A significant re-localization was found in TLR1 expression with a higher percentage of basal and a significantly lower percentage of homogenous epidermal expression in patients (73.3 and 0 %, respectively) compared with controls (13.3 and 73.3 %, respectively) (P < 0.001). TLR2 showed a significantly higher percentage of epidermal expression (more in the upper spinous layer) and significantly lower percentage of epidermal but more basal expression in patients (66.6 and 10 %, respectively) compared with controls (0 and 73.3 %, respectively) (P < 0.001). The median (IQR) of TLR1 [1 (0.75-1)] and TLR2 [1 (1-1)] staining score in patients was significantly lower than that of the controls [2 (1-2) and 1 (1-2), respectively] (P < 0.05). This work thus shows a re-localization of TLR 1 and 2 expression sites with decreased grade of expression in LP lesions. Targeting TLR signaling is expected to be a novel treatment strategy for cutaneous LP.

  6. Toll-like receptor 4 in butylated hydroxytoluene-induced mouse pulmonary inflammation and tumorigenesis.

    PubMed

    Bauer, Alison K; Dixon, Darlene; DeGraff, Laura M; Cho, Hye-Youn; Walker, Christopher R; Malkinson, Alvin M; Kleeberger, Steven R

    2005-12-01

    Because chronic pulmonary diseases predispose to lung neoplasia, the identification of the molecular mechanisms involved could provide novel preventive, diagnostic, and therapeutic strategies. Toll-like receptors (TLRs) transduce exogenous and endogenous signals into the production of inflammatory cytokines to coordinate adaptive immune responses. To determine the role of Tlr4 in chronic lung inflammation, we compared lung permeability, leukocyte infiltration, and nuclear factor kappa B (NFkappaB) and activator protein 1 (AP-1) DNA binding in butylated hydroxytoluene (BHT)-treated (four weekly injections of 125-200 mg/kg each) inbred mouse strains with functional Tlr4 (OuJ and BALB) and mutated Tlr4 (HeJ and BALB(Lps-d)). We also measured primary tumor formation in these mice after single-carcinogen injection (3-methylcholanthrene; 10 microg/kg), followed by BHT treatment (six weekly injections of 125-200 mg/kg each). Mice with functional Tlr4 had reduced lung permeability, leukocyte inflammation, and primary tumor formation (BALB(Lps-d), mean = 22.3 tumors/mouse, versus BALB, mean = 13.9 tumors/mouse, difference = 8.4 tumors/mouse, 95% confidence interval = 4.6 to 12.1 tumors/mouse; P = .025) compared with mice with mutated Tlr4. NFkappaB DNA binding activity was higher in OuJ than in HeJ mice; however, AP-1 activity was elevated in HeJ mice. To our knowledge, this is the first model to demonstrate a modulatory role for Tlr4 in chronic lung inflammation and tumorigenesis.

  7. Central role of liver in anticancer and radioprotective activities of Toll-like receptor 5 agonist.

    PubMed

    Burdelya, Lyudmila G; Brackett, Craig M; Kojouharov, Bojidar; Gitlin, Ilya I; Leonova, Katerina I; Gleiberman, Anatoli S; Aygun-Sunar, Semra; Veith, Jean; Johnson, Christopher; Haderski, Gary J; Stanhope-Baker, Patricia; Allamaneni, Shyam; Skitzki, Joseph; Zeng, Ming; Martsen, Elena; Medvedev, Alexander; Scheblyakov, Dmitry; Artemicheva, Nataliya M; Logunov, Denis Y; Gintsburg, Alexander L; Naroditsky, Boris S; Makarov, Sergei S; Gudkov, Andrei V

    2013-05-14

    Vertebrate Toll-like receptor 5 (TLR5) recognizes bacterial flagellin proteins and activates innate immune responses to motile bacteria. In addition, activation of TLR5 signaling can inhibit growth of TLR5-expressing tumors and protect normal tissues from radiation and ischemia-reperfusion injuries. To understand the mechanisms behind these phenomena at the organismal level, we assessed nuclear factor kappa B (NF-κB) activation (indicative of TLR5 signaling) in tissues and cells of mice treated with CBLB502, a pharmacologically optimized flagellin derivative. This identified the liver and gastrointestinal tract as primary CBLB502 target organs. In particular, liver hepatocytes were the main cell type directly and specifically responding to systemic administration of CBLB502 but not to that of the TLR4 agonist LPS. To assess CBLB502 impact on other pathways, we created multireporter mice with hepatocytes transduced in vivo with reporters for 46 inducible transcription factor families and found that along with NF-κB, CBLB502 strongly activated STAT3-, phenobarbital-responsive enhancer module (PREM), and activator protein 1 (AP-1-) -driven pathways. Livers of CBLB502-treated mice displayed induction of numerous immunomodulatory factors and massive recruitment of various types of immune cells. This led to inhibition of growth of liver metastases of multiple tumors regardless of their TLR5 status. The changed liver microenvironment was not, however, hepatotoxic, because CBLB502 induced resistance to Fas-mediated apoptosis in normal liver cells. Temporary occlusion of liver blood circulation prevented CBLB502 from protecting hematopoietic progenitors in lethally irradiated mice, indicating involvement of a factor secreted by responding liver cells. These results define the liver as the key mediator of TLR5-dependent effects in vivo and suggest clinical applications for TLR5 agonists as hepatoprotective and antimetastatic agents.

  8. Toll-Like Receptor 9 Is Required for Opioid-Induced Microglia Apoptosis

    PubMed Central

    Miao, Junying; Jiang, Yulin; Zhang, Yi; Xiao, Zuoxiang; Hanley, Gregory; Li, Yi; Zhang, Xiumei; LeSage, Gene; Peng, Ying; Yin, Deling

    2011-01-01

    Opioids have been widely applied in clinics as one of the most potent pain relievers for centuries, but their abuse has deleterious physiological effects beyond addiction. However, the underlying mechanism by which microglia in response to opioids remains largely unknown. Here we show that morphine induces the expression of Toll-like receptor 9 (TLR9), a key mediator of innate immunity and inflammation. Interestingly, TLR9 deficiency significantly inhibited morphine-induced apoptosis in microglia. Similar results were obtained when endogenous TLR9 expression was suppressed by the TLR9 inhibitor CpGODN. Inhibition of p38 MAPK by its specific inhibitor SB203580 attenuated morphine-induced microglia apoptosis in wild type microglia. Morphine caused a dramatic decrease in Bcl-2 level but increase in Bax level in wild type microglia, but not in TLR9 deficient microglia. In addition, morphine treatment failed to induce an increased levels of phosphorylated p38 MAPK and MAP kinase kinase 3/6 (MKK3/6), the upstream MAPK kinase of p38 MAPK, in either TLR9 deficient or µ-opioid receptor (µOR) deficient primary microglia, suggesting an involvement of MAPK and µOR in morphine-mediated TLR9 signaling. Moreover, morphine-induced TLR9 expression and microglia apoptosis appears to require μOR. Collectively, these results reveal that opioids prime microglia to undergo apoptosis through TLR9 and µOR as well. Taken together, our data suggest that inhibition of TLR9 and/or blockage of µOR is capable of preventing opioid-induced brain damage. PMID:21559519

  9. Oxidative Stress Increases Surface Toll-Like Receptor 4 Expression in Murine Macrophages Via Ceramide Generation.

    PubMed

    Tawadros, Patrick S; Powers, Kinga A; Ailenberg, Menachem; Birch, Simone E; Marshall, John C; Szaszi, Katalin; Kapus, Andras; Rotstein, Ori D

    2015-08-01

    Multiorgan failure is a major cause of late mortality following trauma. Oxidative stress generated during shock/resuscitation contributes to tissue injury by priming the immune system for an exaggerated response to subsequent inflammatory stimuli, such as lipopolysaccharide (LPS). We recently reported that oxidative stress causes rapid recruitment of the LPS receptor Toll-like receptor 4 (TLR4) to membrane lipid rafts, thus increasing LPS responsiveness and cellular priming. We hypothesized that activation of Src family kinases by oxidants might contribute to these events. We utilized microscopy, flow cytometry, Western blotting, and thin-layer chromatography methods. Using hydrogen peroxide in vitro and hemorrhagic shock/resuscitation in vivo, oxidant-induced TLR4 translocation in macrophages occurred in an Src-dependent manner. Approaches supporting this conclusion included pharmacologic inhibition of the Src family kinases by PP2, Src inhibition by a molecular approach of cell transfection with Csk, and genetic inhibition of all Src kinases relevant to the monocyte/macrophage lineage in hckfgrlyn triple knockout mice. To evaluate the upstream molecules involved in Src activation, we evaluated the ability of oxidative stress to activate the bioactive lipid molecule ceramide. Oxidants induced ceramide generation in macrophages both in vitro and in vivo, an effect that appears to be due to activation of the acid sphingomyelinase. Using pharmacological approaches, ceramide was shown to be both necessary and sufficient to mediate TLR4 translocation to the plasma membrane in an Src-dependent manner. This study identifies a hierarchy of signaling molecules following oxidative stress that might represent novel targets for therapy in critical illness and organ injury.

  10. Targeting Toll-like receptor 4 prevents cobalt-mediated inflammation

    PubMed Central

    Lawrence, Helen; Mawdesley, Amy Elizabeth; Holland, James Patrick; Kirby, John Andrew; Deehan, David John; Tyson-Capper, Alison Jane

    2016-01-01

    Cobalt-chrome alloy is a widely used biomaterial in joint replacements, dental implants and spinal rods. Although it is an effective and biocompatible material, adverse reactions to metal debris (ARMD) have arisen in a minority of patients, particularly in those with metal-on-metal bearing hip replacements. There is currently no treatment for ARMD and once progressive, early revision surgery of the implant is necessary. Therapeutic agents to prevent, halt or reverse ARMD would therefore be advantageous. Cobalt ions activate Toll-like receptor 4 (TLR4), an innate immune receptor responsible for inflammatory responses to bacterial lipopolysaccharide (LPS) resulting in the production of pro-inflammatory cytokines and chemokines. We hypothesised that anti-TLR4 neutralising antibodies, reported to inhibit TLR4-mediated inflammation, could prevent the inflammatory response to cobalt ions in an in vitro macrophagecell culture model. This study shows that a monoclonal anti-TLR4 antibody inhibited cobalt-mediated increases in pro-inflammatory IL8, CCL20 and IL1A expression, as well as IL-8 secretion. In contrast, a polyclonal antibody did not prevent the effect of cobalt ions on either IL-8 or IL1A expression, although it did have a small effect on the CCL20 response. Interestingly, both antibodies inhibited cobalt-mediated neutrophil migration although the greater effect was observed with the monoclonal antibody. In summary our data shows that a monoclonal anti-TLR4 antibody can inhibit cobalt-mediated inflammatory responses while a polyclonal antibody only inhibits the effect of specific cytokines. Anti-TLR4 antibodies have therapeutic potential in ARMD although careful antibody design is required to ensure that the LPS response is preserved. PMID:26840091

  11. Targeting Toll-like receptor 4 prevents cobalt-mediated inflammation.

    PubMed

    Lawrence, Helen; Mawdesley, Amy Elizabeth; Holland, James Patrick; Kirby, John Andrew; Deehan, David John; Tyson-Capper, Alison Jane

    2016-02-16

    Cobalt-chrome alloy is a widely used biomaterial in joint replacements, dental implants and spinal rods. Although it is an effective and biocompatible material, adverse reactions to metal debris (ARMD) have arisen in a minority of patients, particularly in those with metal-on-metal bearing hip replacements. There is currently no treatment for ARMD and once progressive, early revision surgery of the implant is necessary. Therapeutic agents to prevent, halt or reverse ARMD would therefore be advantageous. Cobalt ions activate Toll-like receptor 4 (TLR4), an innate immune receptor responsible for inflammatory responses to bacterial lipopolysaccharide (LPS) resulting in the production of pro-inflammatory cytokines and chemokines. We hypothesised that anti-TLR4 neutralising antibodies, reported to inhibit TLR4-mediated inflammation, could prevent the inflammatory response to cobalt ions in an in vitro macrophage cell culture model. This study shows that a monoclonal anti-TLR4 antibody inhibited cobalt-mediated increases in pro-inflammatory IL8, CCL20 and IL1A expression, as well as IL-8 secretion. In contrast, a polyclonal antibody did not prevent the effect of cobalt ions on either IL-8 or IL1A expression, although it did have a small effect on the CCL20 response. Interestingly, both antibodies inhibited cobalt-mediated neutrophil migration although the greater effect was observed with the monoclonal antibody. In summary our data shows that a monoclonal anti-TLR4 antibody can inhibit cobalt-mediated inflammatory responses while a polyclonal antibody only inhibits the effect of specific cytokines. Anti-TLR4 antibodies have therapeutic potential in ARMD although careful antibody design is required to ensure that the LPS response is preserved.

  12. Polymorphisms in Toll-like receptor genes are associated with vitiligo

    PubMed Central

    Traks, Tanel; Keermann, Maris; Karelson, Maire; Rätsep, Ranno; Reimann, Ene; Silm, Helgi; Vasar, Eero; Kõks, Sulev; Kingo, Külli

    2015-01-01

    Background: The members of Toll-like receptor (TLR) family are responsible for recognizing various molecular patterns associated with pathogens. Their expression is not confined to immune cells and have been detected in skin cells such as keratinocytes and melanocytes. As part of a generated response to pathogens, TLRs are involved in inducing inflammatory mediators to combat these threats. It is therefore not surprising that TLRs have been implicated in inflammatory skin diseases, including atopic dermatitis and psoriasis. Likewise, as key players in autoimmunity, they have been associated with a number of autoimmune diseases. Based on this, the role of TLRs in vitiligo could be suspected, but is yet to be clearly established. Methods: In order to conduct a genetic association analysis, 30 SNPs were selected from TLR1-TLR8 and TLR10 regions to be genotyped in Estonian case-control cohort consisting of 139 vitiligo patients and 307 healthy control individuals. The patients were further analyzed in subgroups based on sex, age of onset, occurrence of vitiligo among relatives, extent of depigmented areas, vitiligo progression activity, appearance of Köbner's phenomenon, existence of halo naevi, and incidence of spontaneous repigmentation. Results: The most notable finding came with SNP rs179020 situated in TLR7 gene, that was associated in entire vitiligo (Padj = 0.0065) and also several subgroup analyses. Other single marker and haplotype analyses pointed to TLR3, TLR4, and TLR10 genes. Conclusions: This study investigated the genetic regions of nine TLR genes in relation to vitiligo susceptibility. The main results were the associations of TLR7 SNPs with vitiligo, while several other associations were obtained from the remaining TLR gene regions. This suggests that in addition to other inflammatory skin diseases, TLRs affect the development of vitiligo, thus making them interesting targets for future research. PMID:26442097

  13. Select steroid hormone glucuronide metabolites can cause Toll-like receptor 4 activation and enhanced pain

    PubMed Central

    Lewis, Susannah S.; Hutchinson, Mark R.; Frick, Morin M.; Zhang, Yingning; Maier, Steven F.; Sammakia, Tarek; Rice, Kenner C.; Watkins, Linda R.

    2014-01-01

    We have recently shown that several classes of glucuronide metabolites, including the morphine metabolite morphine-3-glucuronide and the ethanol metabolite ethyl glucuronide, cause toll like receptor 4 (TLR4)-dependent signalling in vitro and enhanced pain in vivo. Steroid hormones, including estrogens and corticosterone, are also metabolized through glucuronidation. Here we demonstrate that in silico docking predicts that corticosterone, corticosterone-21-glucuronide, estradiol, estradiol-3-glucuronide and estradiol-17-glucuronide all dock with the MD-2 component of the TLR4 receptor complex. In addition to each docking with MD-2, the docking of each was altered by pre-docking with (+)-naloxone, a TLR4 signaling inhibitor. As agonist versus antagonist activity cannot be determined from these in silico interactions, an in vitro study was undertaken to clarify which of these compounds can act in an agonist fashion. Studies using a cell line transfected with TLR4, necessary co-signaling molecules, and a reporter gene revealed that only estradiol-3-glucuronide and estradiol-17-glucuronide increased reporter gene product, indicative of TLR4 agonism. Finally, in in vivo studies, each of the 5 drugs was injected intrathecally at equimolar doses. In keeping with the in vitro results, only estradiol-3-glucuronide and estradiol-17-glucuronide caused enhanced pain. For both compounds, pain enhancement was blocked by the TLR4 antagonist lipopolysaccharide from Rhodobacter sphaeroides, evidence for the involvement in TLR4 in the resultant pain enhancement. These findings have implications for several chronic pain conditions, including migraine and tempromandibular joint disorder, in which pain episodes are more likely in cycling females when estradiol is decreasing and estradiol metabolites are at their highest. PMID:25218902

  14. Anti-radiation damage effect of polyethylenimine as a toll-like receptor 5 targeted agonist.

    PubMed

    Hu, Zhiqiang; Xing, Yaling; Qian, Yuanyu; Chen, Xiaojuan; Tu, Jian; Ren, Lening; Wang, Kai; Chen, Zhongbin

    2013-03-01

    A number of agents are now available for use in protecting against ionizing radiation. These radiation-protective agents, however, have many adverse effects. Efforts have been made to develop new radiation-protective agents for medical application. Here, we investigated whether a compound, polyethylenimine (PEI), which activates Toll-like receptor 5 (TLR5)-mediated NF-kB signaling pathways, could have an anti-radiation effect on a mouse model. First, a cell-based screening model for an agonist of TLR5-mediated NF-kB pathway was established and then validated by activation of TLR5-mediated NF-kB luciferase reporter activity with a known TLR5 agonist, flagellin. We found that PEI induced dose-dependent activation of the TLR5-mediated NF-kB pathway, indicating that PEI is indeed a TLR5 agonist. Furthermore, the anti-radiation effect of polyethylenimine was assessed using a γ-ray total body irradiation (TBI) mouse model. Compared with the irradiation control, both survival time and survival rate were significantly improved in mice that received either a low dose of polyethylenimine (P= 0.019) or a high dose of polyethylenimine (P< 0.001). We also observed a positive correlation between animal body weight and survival time in mice that received a low dose of polyethylenimine, a high dose of polyethylenimine and amifostine, over a period of 30 days, r= 0.42 (P< 0.02), 0.72 (P< 0.0001) and 0.95 (P< 0.0001), respectively, while a negative correlation between animal body weight and survival time was observed in the irradiation control (r= -0.89; P< 0.0001). These results indicate that polyethylenimine is a new TLR5 agonist with potential application in offering protection for patients receiving radiotherapy or in radiation-related accidents.

  15. Effects of particle size on toll-like receptor 9-mediated cytokine profiles

    PubMed Central

    Chen, Helen C.; Sun, Bingbing; Tran, Kenny K.; Shen, Hong

    2010-01-01

    Biomaterials interface with toll-like receptor (TLR) 9-mediated innate immunity in a wide range of medical applications, such as tissue implants and drug delivery systems. The stimulation of TLR9 can lead to two different signaling pathways, resulting in the generation of proinflammatory cytokines (i.e. IL-6) and/or type I interferons (IFNs, i.e. IFN-α). These two categories of cytokines differentially influence both innate and adaptive immunity. Although particle size is known to be a critical parameter of biomaterials, its role in TLR9-mediated cytokine profiles is not clear. Here, we examined how the size of biomaterials impacted cytokine profiles by using polystyrene particles of defined sizes as model carriers for TLR9 agonists (CpG oligonucleotides (CpG ODNs)). CpG ODNs bound to nano- to submicro- particles stimulated the production of both IL-6 and IFN-α, while those bound to microparticles resulted in IL-6 secretions only. The differential TLR9-mediated cytokine profiles were attributed to the pH of endosomes that particles trafficked to. The magnitude of IFN-α production was highly sensitive to the change in endosomal pH in comparison to that of IL-6. Our results define two critical design variables, size and the ability to modulate endosomal pH, for the engineering of biomaterials that potentially interface with TLR9-mediated innate immunity. The fine control of these two variables will allow us to fully exploit the beneficial facets of TLR9-mediated innate immunity while minimizing undesirable side effects. PMID:21126760

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

    PubMed

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

    2016-01-01

    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.

  17. Toll-like receptor 4 contributes to acute kidney injury after cardiopulmonary resuscitation in mice

    PubMed Central

    Zhang, Qingsong; Li, Gang; Xu, Li; Li, Qian; Wang, Qianyan; Zhang, Yue; Zhang, Qing; Sun, Peng

    2016-01-01

    Toll-like receptor 4 (TLR4) activation mediates renal injury in regional ischemia and reperfusion (I/R) models generated by clamping renal pedicles. However, it remains unclear whether TLR4 is causal in the kidney injury following global I/R induced by cardiac arrest (CA) and cardiopulmonary resuscitation (CPR). The present study used wild-type (C3H/HeN) and TLR4-mutant (C3H/HeJ) mice to produce the CA/CPR model. CA was induced by injection of cold KCl and left untreated for different time periods. After resuscitation (72 h), the level of blood urea nitrogen (BUN) and serum creatinine (Scr), as well as histological changes in renal tissue were assessed to evaluate the severity of acute kidney injury (AKI). The expression of TLR4, intercellular adhesion molecule-1 (ICAM-1), myeloperoxidase (MPO) and growth-regulated oncogene-β (GRO-β) in kidney tissues was detected. The results demonstrated that the levels of Scr and BUN increased significantly in C3H/HeN and C3H/HeJ mice after CPR. CPR also resulted in increased expression of TLR4, ICAM-1, GRO-β and MPO in a CA-duration dependent manner. However, there was decreased expression of ICAM-1, GRO-β and MPO in C3H/HeJ mice compared with that in C3H/HeN mice. C3H/HeJ mice were resistant to AKI as demonstrated by the minor changes in renal histology and function following CPR. In conclusion, mice suffered from AKI after successful CPR and severe AKI occurred in mice with prolonged CA duration. TLR4 and its downstream signaling events that promote neutrophil infiltration via ICAM-1 and GRO-β may be important in mediating inflammatory responses to renal injury after CPR. PMID:27510583

  18. Tenascin C upregulates interleukin-6 expression in human cardiac myofibroblasts via toll-like receptor 4

    PubMed Central

    Maqbool, Azhar; Spary, Emma J; Manfield, Iain W; Ruhmann, Michaela; Zuliani-Alvarez, Lorena; Gamboa-Esteves, Filomena O; Porter, Karen E; Drinkhill, Mark J; Midwood, Kim S; Turner, Neil A

    2016-01-01

    AIM: To investigate the effect of Tenascin C (TNC) on the expression of pro-inflammatory cytokines and matrix metalloproteinases in human cardiac myofibroblasts (CMF). METHODS: CMF were isolated and cultured from patients undergoing coronary artery bypass grafting. Cultured cells were treated with either TNC (0.1 μmol/L, 24 h) or a recombinant protein corresponding to different domains of the TNC protein; fibrinogen-like globe (FBG) and fibronectin type III-like repeats (TNIII 5-7) (both 1 μmol/L, 24 h). The expression of the pro-inflammatory cytokines; interleukin (IL)-6, IL-1β, TNFα and the matrix metalloproteinases; MMPs (MMP1, 2, 3, 9, 10, MT1-MMP) was assessed using real time RT-PCR and western blot analysis. RESULTS: TNC increased both IL-6 and MMP3 (P < 0.01) mRNA levels in cultured human CMF but had no significant effect on the other markers studied. The increase in IL-6 mRNA expression was mirrored by an increase in protein secretion as assessed by enzyme-linked immunosorbant assay (P < 0.01). Treating CMF with the recombinant protein FBG increased IL-6 mRNA and protein (P < 0.01) whereas the recombinant protein TNIII 5-7 had no effect. Neither FBG nor TNIII 5-7 had any significant effect on MMP3 expression. The expression of toll-like receptor 4 (TLR4) in human CMF was confirmed by real time RT-PCR, western blot and immunohistochemistry. Pre-incubation of cells with TLR4 neutralising antisera attenuated the effect of both TNC and FBG on IL-6 mRNA and protein expression. CONCLUSION: TNC up-regulates IL-6 expression in human CMF, an effect mediated through the FBG domain of TNC and via the TLR4 receptor. PMID:27231521

  19. Regulation of angiogenesis, mural cell recruitment and adventitial macrophage behavior by Toll-like receptors.

    PubMed

    Aplin, Alfred C; Ligresti, Giovanni; Fogel, Eric; Zorzi, Penelope; Smith, Kelly; Nicosia, Roberto F

    2014-01-01

    The angiogenic response to injury can be studied by culturing rat or mouse aortic explants in collagen gels. Gene expression studies show that aortic angiogenesis is preceded by an immune reaction with overexpression of Toll-like receptors (TLRs) and TLR-inducible genes. TLR1, 3, and 6 are transiently upregulated at 24 h whereas TLR2, 4, and 8 expression peaks at 24 h but remains elevated during angiogenesis and vascular regression. Expression of TLR5, 7 and 9 steadily increases over time and is highest during vascular regression. Studies with isolated cells show that TLRs are expressed at higher levels in aortic macrophages compared to endothelial or mural cells with the exception of TLR2 and TLR9 which are more abundant in the aortic endothelium. LPS and other TLR ligands dose dependently stimulate angiogenesis and vascular endothelial growth factor production. TLR9 ligands also influence the behavior of nonendothelial cell types by blocking mural cell recruitment and inducing formation of multinucleated giant cells by macrophages. TLR9-induced mural cell depletion is associated with reduced expression of the mural cell recruiting factor PDGFB. The spontaneous angiogenic response of the aortic rings to injury is reduced in cultures from mice deficient in myeloid differentiation primary response 88 (MyD88), a key adapter molecule of TLRs, and following treatment with an inhibitor of the NFκB pathway. These results suggest that the TLR system participates in the angiogenic response of the vessel wall to injury and may play an important role in the regulation of inflammatory angiogenesis in reactive and pathologic processes.

  20. Toll-like receptor 11-initiated innate immune response in male mouse germ cells.

    PubMed

    Chen, Qiaoyuan; Zhu, Weiwei; Liu, Zhenghui; Yan, Keqin; Zhao, Shutao; Han, Daishu

    2014-02-01

    Toxoplasma gondii and uropathogenic Escherichia coli (UPEC) may infect the testis and impair testicular function. Mechanisms underlying testicular innate immune response to these two pathogens remain to be clarified. The present study examined the function of TLR11, which can be recognized by T. gondii-derived profilin and UPEC, in initiating innate immune response in male mouse germ cells. TLR11 is predominantly expressed in spermatids. Profilin and UPEC induced the expressions of different inflammatory cytokine profiles in the germ cells. In particular, profilin induced the expressions of macrophage chemotactic protein 1 (MCP1), interleukin 12 (IL12), and interferon gamma (IFNG) through nuclear factor KB (NFKB) activation. UPEC induced the expressions of MCP1, IL12, and IFNG, as well as tumor necrosis factor alpha (TNFA), IL6, and IFNB, through the activation of NFKB, IFN regulatory factor 3, and mitogen-activated protein kinases. Evidence showed that profilin induced the innate response in male germ cells through TLR11 signaling, and UPEC triggered the response through TLR11 and other TLR-signaling pathways. We also provided evidence that local injection of profilin or UPEC induces the innate immune response in the germ cells. Data describe TLR11-mediated innate immune function of male germ cells in response to T. gondii profilin and UPEC stimulations. This system may play a role in testicular defense against T. gondii and UPEC infections in mice.

  1. Advances in the design and delivery of peptide subunit vaccines with a focus on Toll-like receptor agonists

    PubMed Central

    Black, Matthew; Trent, Amanda; Tirrell, Matthew; Olive, Colleen

    2010-01-01

    Considerable success has been made with many peptide antigen formulations, and peptide-based vaccines are emerging as the next generation of prophylactic and remedial immunotherapy. However, finding an optimal platform balancing all of the requirements for an effective, specific and safe immune response remains a major challenge for many infectious and chronic diseases. This review outlines how peptide immunogenicity is influenced by the way in which peptides are presented to the immune system, underscoring the need for multifunctional delivery systems that couple antigen and adjuvant into a single construct. Particular attention is given to the ability of Toll-like receptor agonists to act as adjuvants. A survey of recent approaches to developing peptide antigen delivery systems is given, many of which incorporate Toll-like receptor agonists into the design. PMID:20109027

  2. Progressive Hearing Impairment in Children with Congenital Cytomegalovirus Infection.

    ERIC Educational Resources Information Center

    Dahle, Arthur J.; And Others

    1979-01-01

    Audiological assessment of 86 children (mean age 38 months at last evaluation time) with congenital cytomegalovirus infection revealed progressive hearing loss in four of 12 Ss with sensorineural hearing impairments. Case descriptions documented the progression of the hearing loss. (Author)

  3. Control of Toll-like receptor-mediated T cell-independent type 1 antibody responses by the inducible nuclear protein IκB-ζ.

    PubMed

    Hanihara-Tatsuzawa, Fumito; Miura, Hanae; Kobayashi, Shuhei; Isagawa, Takayuki; Okuma, Atsushi; Manabe, Ichiro; MaruYama, Takashi

    2014-11-01

    Antibody responses have been classified as being either T cell-dependent or T cell-independent (TI). TI antibody responses are further classified as being either type 1 (TI-1) or type 2 (TI-2), depending on their requirement for B cell-mediated antigen receptor signaling. Although the mechanistic basis of antibody responses has been studied extensively, it remains unclear whether different antibody responses share similarities in their transcriptional regulation. Here, we show that mice deficient in IκB-ζ, specifically in their B cells, have impaired TI-1 antibody responses but normal T cell-dependent and TI-2 antibody responses. The absence of IκB-ζ in B cells also impaired proliferation triggered by Toll-like receptor (TLR) activation, plasma cell differentiation, and class switch recombination (CSR). Mechanistically, IκB-ζ-deficient B cells could not induce TLR-mediated induction of activation-induced cytidine deaminase (AID), a class-switch DNA recombinase. Retroviral transduction of AID in IκB-ζ-deficient B cells restored CSR activity. Furthermore, acetylation of histone H3 in the vicinity of the transcription start site of the gene that encodes AID was reduced in IκB-ζ-deficient B cells relative to IκB-ζ-expressing B cells. These results indicate that IκB-ζ regulates TLR-mediated CSR by inducing AID. Moreover, IκB-ζ defines differences in the transcriptional regulation of different antibody responses.

  4. MyD88-dependent Toll-like receptor 4 signal pathway in intervertebral disc degeneration

    PubMed Central

    Qin, Chuqiang; Zhang, Bo; Zhang, Liang; Zhang, Zhi; Wang, Le; Tang, Long; Li, Shuangqing; Yang, Yixi; Yang, Fuguo; Zhang, Ping; Yang, Bo

    2016-01-01

    Lower back pain (LBP) is a common and remitting problem. One of the primary causes of LBP is thought to be degeneration of the intervertebral disc (IVD). The aim of the present study was to investigate the role of the myeloid differentiation primary-response protein 88 (MyD88)-dependent Toll-like receptor 4 (TLR4) signal pathway in the mechanism of IVD degeneration. IVD nucleus pulposus cells isolated and cultured from the lumbar vertebrae of Wistar rats were stimulated by various doses of lipopolysaccharide (LPS; 0.1, 1, 10 and 100 µg/ml) to simulate IVD degeneration. Cells were rinsed and cultured in serum-free Dulbecco's modified Eagle's medium/F12. Reverse transcription-quantitative polymerase chain reaction was used to determine the levels of TLR4, MyD88, tumor necrosis factor α (TNFα), and interleukin-1β (IL-1β) mRNA expression after 1, 3, 6, 9 and 12 h of incubation. Additionally, western blot and enzyme-linked immunosorbent assay analyses were used to determine the levels of TLR4, MyD88, TNFα, and IL-1β protein expression after 24, 48 and 72 h of incubation. The levels of TLR4, MyD88, TNFα and IL-1β mRNA all increased in the cells stimulated by 10 µg/ml LPS at 3, 6 and 9 h (all P<0.001). Furthermore, the levels of TLR4, MyD88, TNFα and IL-1β protein all increased at 24, 48 and 72 h (all P<0.001). Additionally, the mRNA and protein levels of TLR4, MyD88, TNFα and IL-1β increased significantly in the cells stimulated by 1, 10 and 100 µg/ml LPS compared with the control group, and reached a peak in the 10 µg/ml LPS group (all P<0.001). These results suggest that the MyD88-dependent TLR4 signal pathway is a target pathway in IVD degeneration. This pathway is time phase- and dose-dependent, and when activated can lead to the release of inflammatory factors that participate in IVD degeneration. PMID:27446251

  5. Molecular evolution of bovine Toll-like receptor 2 suggests substitutions of functional relevance

    PubMed Central

    2008-01-01

    Background There is accumulating evidence that polymorphism in Toll-like receptor (TLR) genes might be associated with disease resistance or susceptibility traits in livestock. Polymorphic sites affecting TLR function should exhibit signatures of positive selection, identified as a high ratio of non-synonymous to synonymous nucleotide substitutions (ω). Phylogeny based models of codon substitution based on estimates of ω for each amino acid position can therefore offer a valuable tool to predict sites of functional relevance. We have used this approach to identify such polymorphic sites within the bovine TLR2 genes from ten Bos indicus and Bos taurus cattle breeds. By analysing TLR2 gene phylogeny in a set of mammalian species and a subset of ruminant species we have estimated the selective pressure on individual sites and domains and identified polymorphisms at sites of putative functional importance. Results The ω were highest in the mammalian TLR2 domains thought to be responsible for ligand binding and lowest in regions responsible for heterodimerisation with other TLR-related molecules. Several positively-selected sites were detected in or around ligand-binding domains. However a comparison of the ruminant subset of TLR2 sequences with the whole mammalian set of sequences revealed that there has been less selective pressure among ruminants than in mammals as a whole. This suggests that there have been functional changes during ruminant evolution. Twenty newly-discovered non-synonymous polymorphic sites were identified in cattle. Three of them were localised at positions shaped by positive selection in the ruminant dataset (Leu227Phe, His305Pro, His326Gln) and in domains involved in the recognition of ligands. His326Gln is of particular interest as it consists of an exchange of differentially-charged amino acids at a position which has previously been shown to be crucial for ligand binding in human TLR2. Conclusion Within bovine TLR2, polymorphisms at amino

  6. TRIF mediates Toll-like receptor 5-induced signaling in intestinal epithelial cells.

    PubMed

    Choi, Yoon Jeong; Im, Eunok; Chung, Hyo Kyun; Pothoulakis, Charalabos; Rhee, Sang Hoon

    2010-11-26

    Toll-like receptors (TLRs) associate with adaptor molecules (MyD88, Mal/TIRAP, TRAM, and TRIF) to mediate signaling of host-microbial interaction. For instance, TLR4 utilizes the combination of both Mal/TIRAP-MyD88 (MyD88-dependent pathway) and TRAM-TRIF (MyD88-independent pathway). However, TLR5, the specific receptor for flagellin, is known to utilize only MyD88 to elicit inflammatory responses, and an involvement of other adaptor molecules has not been suggested in TLR5-dependent signaling. Here, we found that TRIF is involved in mediating TLR5-induced nuclear factor κB (NFκB) and mitogen-activated protein kinases (MAPKs), specifically JNK1/2 and ERK1/2, activation in intestinal epithelial cells. TLR5 activation by flagellin permits the physical interaction between TLR5 and TRIF in human colonic epithelial cells (NCM460), whereas TLR5 does not interact with TRAM upon flagellin stimulation. Both primary intestinal epithelial cells from TRIF-KO mice and TRIF-silenced NCM460 cells significantly reduced flagellin-induced NFκB (p105 and p65), JNK1/2, and ERK1/2 activation compared with control cells. However, p38 activation by flagellin was preserved in these TRIF-deficient cells. TRIF-KO intestinal epithelial cells exhibited substantially reduced inflammatory cytokine (keratinocyte-derived cytokine, macrophage inflammatory protein 3α, and IL-6) expression upon flagellin, whereas control cells from TRIF-WT mice showed robust cytokine expression by flagellin. Compare with TRIF-WT mice, TRIF-KO mice were resistant to in vivo intestinal inflammatory responses: flagellin-mediated exacerbation of colonic inflammation and dextran sulfate sodium-induced experimental colitis. We conclude that in addition to MyD88, TRIF mediates TLR5-dependent responses and, thereby regulates inflammatory responses elicited by flagellin/TLR5 engagement. Our findings suggest an important role of TRIF in regulating host-microbial communication via TLR5 in the gut epithelium.

  7. 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

  8. Toll-like receptor signaling in colorectal cancer: carcinogenesis to cancer therapy.

    PubMed

    Li, Ting-Ting; Ogino, Shuji; Qian, Zhi Rong

    2014-12-21

    Toll-like receptors (TLRs) are germ line encoded innate immune sensors that recognize conserved microbial structures and host alarmins, and signal expression of major histocompatibility complex proteins, costimulatory molecules, and inflammatory mediators by macrophages, neutrophils, dendritic cells, and other cell types. These protein receptors are characterized by their ability to respond to invading pathogens promptly by recognizing particular TLR ligands, including flagellin and lipopolysaccharide of bacteria, nucleic acids derived from viruses, and zymosan of fungi. There are 2 major TLR pathways; one is mediated by myeloid differentiation factor 88 (MYD88) adaptor proteins, and the other is independent of MYD88. The MYD88-dependent pathway involves early-phase activation of nuclear factor of kappa light polypeptide gene enhancer in B-cells 1 (NF-κB1) and all the TLRs, except TLR3, have been shown to activate this pathway. TLR3 and TLR4 act via MYD88-independent pathways with delayed activation of NF-κB signaling. TLRs play a vital role in activating immune responses. TLRs have been shown to mediate inflammatory responses and maintain epithelial barrier homeostasis, and are highly likely to be involved in the activation of a number of pathways following cancer therapy. Colorectal cancer (CRC) is one of the most common cancers, and accounts for almost half a million deaths annually worldwide. Inflammation is considered a risk factor for many common malignancies including cancers of the colorectum. The key molecules involved in inflammation-driven carcinogenesis include TLRs. As sensors of cell death and tissue remodeling, TLRs may have a universal role in canc