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Sample records for activates toll-like receptor

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

    DEFF Research Database (Denmark)

    Weintz, Gabriele; Olsen, Jesper Velgaard; Frühauf, Katja;

    2010-01-01

    Recognition of microbial danger signals by toll-like receptors (TLR) causes re-programming of macrophages. To investigate kinase cascades triggered by the TLR4 ligand lipopolysaccharide (LPS) on systems level, we performed a global, quantitative and kinetic analysis of the phosphoproteome...

  2. HIV-1 activates macrophages independent of Toll-like receptors.

    Directory of Open Access Journals (Sweden)

    Joseph N Brown

    Full Text Available BACKGROUND: Macrophages provide an interface between innate and adaptive immunity and are important long-lived reservoirs for Human Immunodeficiency Virus Type-1 (HIV-1. Multiple genetic networks involved in regulating signal transduction cascades and immune responses in macrophages are coordinately modulated by HIV-1 infection. METHODOLOGY/PRINCIPAL FINDINGS: To evaluate complex interrelated processes and to assemble an integrated view of activated signaling networks, a systems biology strategy was applied to genomic and proteomic responses by primary human macrophages over the course of HIV-1 infection. Macrophage responses, including cell cycle, calcium, apoptosis, mitogen-activated protein kinases (MAPK, and cytokines/chemokines, to HIV-1 were temporally regulated, in the absence of cell proliferation. In contrast, Toll-like receptor (TLR pathways remained unaltered by HIV-1, although TLRs 3, 4, 7, and 8 were expressed and responded to ligand stimulation in macrophages. HIV-1 failed to activate phosphorylation of IRAK-1 or IRF-3, modulate intracellular protein levels of Mx1, an interferon-stimulated gene, or stimulate secretion of TNF, IL-1beta, or IL-6. Activation of pathways other than TLR was inadequate to stimulate, via cross-talk mechanisms through molecular hubs, the production of proinflammatory cytokines typical of a TLR response. HIV-1 sensitized macrophage responses to TLR ligands, and the magnitude of viral priming was related to virus replication. CONCLUSIONS/SIGNIFICANCE: HIV-1 induced a primed, proinflammatory state, M1(HIV, which increased the responsiveness of macrophages to TLR ligands. HIV-1 might passively evade pattern recognition, actively inhibit or suppress recognition and signaling, or require dynamic interactions between macrophages and other cells, such as lymphocytes or endothelial cells. HIV-1 evasion of TLR recognition and simultaneous priming of macrophages may represent a strategy for viral survival, contribute

  3. DMPD: Proximal effects of Toll-like receptor activation in dendritic cells. [Dynamic Macrophage Pathway CSML Database

    Lifescience Database Archive (English)

    Full Text Available 17142025 Proximal effects of Toll-like receptor activation in dendritic cells. Watt...) (.svg) (.html) (.csml) Show Proximal effects of Toll-like receptor activation in dendritic cells. PubmedID... 17142025 Title Proximal effects of Toll-like receptor activation in dendritic ce

  4. Activation of toll-like receptors and dendritic cells by a broad range of bacterial molecules

    NARCIS (Netherlands)

    Boele, L.C.L.; Bajramovic, J.J.; Vries, A.M.M.B.C. de; Voskamp-Visser, I.A.I.; Kaman, W.E.; Kleij, D. van der

    2009-01-01

    Activation of pattern recognition receptors such as Toll-like receptors (TLRs) by pathogens leads to activation and maturation of dendritic cells (DC), which orchestrate the development of the adaptive immune response. To create an overview of the effects of a broad range of pathogenic bacteria, the

  5. Glucose activation of islets of Langerhans up-regulates Toll-like receptor 5: possible mechanism of protection

    DEFF Research Database (Denmark)

    Weile, Christian Roar Andersen; Josefsen, Knud Elnegaard; Buschard, Karsten Stig

    2011-01-01

    Toll-like receptors are pattern-recognition receptors of the innate immune system that are activated during viral, bacterial or other infections, as well as during disease progression of type 1 and type 2 diabetes. Toll-like receptor 5 (TLR-5) specifically recognizes bacterial infection through b...

  6. FATTY ACIDS MODULATE TOLL-LIKE RECEPTOR 4 ACTIVATION THROUGH REGULATION OF RECEPTOR DIMERIZATION AND RECRUITMENT INTO LIPID RAFTS

    Science.gov (United States)

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

    Science.gov (United States)

    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.

  8. Toll-Like Receptor 4 Activation in Cancer Progression and Therapy

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    Alja Oblak

    2011-01-01

    Full Text Available Cancer immunotherapy has been the focus of intense research since the late 19th century when Coley observed that bacterial components can contribute to cancer regression by eliciting an antitumor immune response. Successful activation and maturation of tumor-specific immune cells is now known to be mediated by bacterial endotoxin, which activates Toll-like receptor 4 (TLR4. TLR4 is expressed on a variety of immune as well as tumor cells, but its activation can have opposing effects. While TLR4 activation can promote antitumor immunity, it can also result in increased tumor growth and immunosuppression. Nevertheless, TLR4 engagement by endotoxin as well as by endogenous ligands represents notable contribution to the outcome of different cancer treatments, such as radiation or chemotherapy. Further research of the role and mechanisms of TLR4 activation in cancer may provide novel antitumor vaccine adjuvants as well as TLR4 inhibitors that could prevent inflammation-induced carcinogenesis.

  9. Nuclear Factor-κB: Activation and Regulation during Toll-like Receptor Signaling

    Institute of Scientific and Technical Information of China (English)

    Ruaidhrí J. Carmody; Youhai H. Chen

    2007-01-01

    Toll-like receptors (TLRs) recognize distinct microbial components to initiate the innate and adaptive immune responses. TLR activation culminates in the expression of appropriate pro-inflammatory and immunomodulatory factors to meet pathogenic challenges. The transcription factor NF-κB is the master regulator of all TLR-induced responses and its activation is the pivotal event in TLR-mediated activation of the innate immune response. Many of the key molecular events required for TLR-induced NF-κB activation have been elucidated. However, much remain to be learned about the ability of TLRs to generate pathogen-specific responses using a limited number of transcription factors. This review will focus on our current understanding of NF-κB activation by TLRs and potential mechanisms for achieving a signal-specific response through NF-κB.

  10. DMPD: Crosstalk among Jak-STAT, Toll-like receptor, and ITAM-dependent pathways inmacrophage activation. [Dynamic Macrophage Pathway CSML Database

    Lifescience Database Archive (English)

    Full Text Available 17502339 Crosstalk among Jak-STAT, Toll-like receptor, and ITAM-dependent pathways inmacrophage activation...T, Toll-like receptor, and ITAM-dependent pathways inmacrophage activation. Authors Hu X, Chen J, Wang L, Iv...ivation. PubmedID 17502339 Title Crosstalk among Jak-STA...May 14. (.png) (.svg) (.html) (.csml) Show Crosstalk among Jak-STAT, Toll-like receptor, and ITAM-dependent pathways inmacrophage act

  11. Toll-like receptors in neonatal sepsis.

    LENUS (Irish Health Repository)

    O'Hare, Fiona M

    2013-06-01

    Toll-like receptors are vital transmembrane receptors that initiate the innate immune response to many micro-organisms. The discovery of these receptors has improved our understanding of host-pathogen interactions, and these receptors play an important role in the pathogenesis of multiple neonatal conditions such as sepsis and brain injury. Toll-like receptors, especially TLRs 2 and 4, are associated with necrotizing enterocolitis, periventricular leukomalacia and sepsis.

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

    Directory of Open Access Journals (Sweden)

    Bo Yoon Chang

    2015-10-01

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

    Science.gov (United States)

    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.

  14. Role of Toll-like receptors in immune activation and tolerance in the liver

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    Nobuhiro eNakamoto

    2014-05-01

    Full Text Available Liver has a unique vascular system receiving the majority of the blood supply from the gastrointestinal tract through the portal vein and faces continuous exposure to foreign pathogens and commensal bacterial products. These gut-derived antigens stimulate liver cells and result in a distinctive immune response via a family of pattern recognition receptors, the Toll-like receptors (TLRs. TLRs are expressed on Kupffer cells, dendritic cells, hepatic stellate cells, endothelial cells, and hepatocytes in the liver. The crosstalk between gut-derived antigens and TLRs on immune cells trigger a distinctive set of mechanisms to induce immunity, contributing to various acute and chronic liver diseases including liver cirrhosis and hepatocellular carcinoma. Accumulating evidence has shown that TLRs stimulation by foreign antigens induces the production of immunoactivating and immunoregulatory cytokines. Furthermore, the immunoregulatory arm of TLR stimulation can also controls excessive tissue damage. With this knowledge at hand, it is important to clarify the dual role of disease-specific TLRs as activators and regulators, especially in the liver. We will review the current understanding of TLR signaling and subsequent immune activation and tolerance by the innate immune system in the liver.

  15. Toll-Like Receptor 4 Reduces Oxidative Injury via Glutathione Activity in Sheep

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    Shoulong Deng

    2016-01-01

    Full Text Available 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.

  16. Activation of Dendritic Cells by the Novel Toll-Like Receptor 3 Agonist RGC100

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    Kai Naumann

    2013-01-01

    Full Text Available Toll-like receptor (TLR 3 agonists emerged as attractive candidates for vaccination strategies against tumors and pathogens. An important mechanism of action of such agonists is based on the activation of TLR3-expressing dendritic cells (DCs, which display a unique capacity to induce and stimulate T-cell responses. In this context, it has been demonstrated that targeting of TLR3 by double-stranded RNA such as poly(I:C results in potent activation of DCs. Major disadvantages of poly(I:C comprise its undefined chemical structure and very poor homogeneity, with subsequent unpredictable pharmacokinetics and high toxicity. In the present study, we evaluated the physicochemical properties and biological activity of the novel TLR3 agonist RGC100. RGC100 has a defined chemical structure, with a defined length (100 bp and molecular weight (64.9 KDa and a good solubility. RGC100 is stable in serum and activates myeloid DCs through TLR3 targeting, as evidenced by gene silencing experiments. Activation of mouse and human myeloid CD1c+ DCs by RGC100 leads to secretion of several proinflammatory cytokines. In addition, RGC100 improves the ability of CD1c+ DCs to stimulate T-cell proliferation. Due to its physicochemical properties and its immunostimulatory properties, RGC100 may represent a promising adjuvant for prophylactic and therapeutic vaccination strategies.

  17. γ-Glutamyltranspeptidase is an endogenous activator of Toll-like receptor 4-mediated osteoclastogenesis

    Science.gov (United States)

    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

  18. Starring role of toll-like receptor-4 activation in the gutliver axis

    Institute of Scientific and Technical Information of China (English)

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

    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.

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

    OpenAIRE

    Hutchinson, M R; Northcutt, A.L.; Hiranita, T.; WANG, X; Lewis, S.; Thomas, J.; van Steeg, K.; Kopajtic, T.A.; L. Loram; Sfregola, C.; Galer, E.; Miles, N.E.; Bland, S.T.; AMAT, J.; Rozeske, R.R.

    2012-01-01

    Opioid action was thought to exert reinforcing effects solely via the initial agonism of opioid receptors. Here we present evidence for an additional novel contributor to opioid reward: the innate immune pattern-recognition receptor, Toll-like receptor 4 (TLR4), and its MyD88-dependent signaling. Blockade of TLR4/MD2 by administration of the non-opioid, unnatural isomer of naloxone, (+)-naloxone (rats), or two independent genetic knockouts of MyD88-TLR4-dependent signaling (mice), suppressed ...

  20. Rice Bran Feruloylated Oligosaccharides Activate Dendritic Cells via Toll-Like Receptor 2 and 4 Signaling

    Directory of Open Access Journals (Sweden)

    Chi Chen Lin

    2014-04-01

    Full Text Available This work presents the effects of feruloylated oligosaccharides (FOs of rice bran on murine bone marrow-derived dendritic cells (BMDCs and the potential pathway through which the effects are mediated. We found that FOs induced phenotypic maturation of DCs, as shown by the increased expression of CD40, CD80/CD86 and MHC-I/II molecules. FOs efficiently induced maturation of DCs generated from C3H/HeN or C57BL/6 mice with normal toll-like receptor 4 (TLR-4 or TLR-2 but not DCs from mice with mutated TLR4 or TLR2. The mechanism of action of FOs may be mediated by increased phosphorylation of ERK, p38 and JNK mitogen-activated protein kinase (MAPKs and increased NF-kB activity, which are important signaling molecules downstream of TLR-4 and TLR-2. These data suggest that FOs induce DCs maturation through TLR-4 and/or TLR-2 and that FOs might have potential efficacy against tumor or virus infection or represent a candidate-adjuvant approach for application in immunotherapy and vaccination.

  1. Bovine lactoferrin counteracts Toll-like receptor mediated activation signals in antigen presenting cells.

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    Patrizia Puddu

    Full Text Available Lactoferrin (LF, a key element in mammalian immune system, plays pivotal roles in host defence against infection and excessive inflammation. Its protective effects range from direct antimicrobial activities against a large panel of microbes, including bacteria, viruses, fungi and parasites, to antinflammatory and anticancer activities. In this study, we show that monocyte-derived dendritic cells (MD-DCs generated in the presence of bovine LF (bLF fail to undergo activation by up-modulating CD83, co-stimulatory and major histocompatibility complex molecules, and cytokine/chemokine secretion. Moreover, these cells are weak activators of T cell proliferation and retain antigen uptake activity. Consistent with an impaired maturation, bLF-MD-DC primed T lymphocytes exhibit a functional unresponsiveness characterized by reduced expression of CD154 and impaired expression of IFN-γ and IL-2. The observed imunosuppressive effects correlate with an increased expression of molecules with negative regulatory functions (i.e. immunoglobulin-like transcript 3 and programmed death ligand 1, indoleamine 2,3-dioxygenase, and suppressor of cytokine signaling-3. Interestingly, bLF-MD-DCs produce IL-6 and exhibit constitutive signal transducer and activator of transcription 3 activation. Conversely, bLF exposure of already differentiated MD-DCs completely fails to induce IL-6, and partially inhibits Toll-like receptor (TLR agonist-induced activation. Cell-specific differences in bLF internalization likely account for the distinct response elicited by bLF in monocytes versus immature DCs, providing a mechanistic base for its multiple effects. These results indicate that bLF exerts a potent anti-inflammatory activity by skewing monocyte differentiation into DCs with impaired capacity to undergo activation and to promote Th1 responses. Overall, these bLF-mediated effects may represent a strategy to block excessive DC activation upon TLR-induced inflammation, adding

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

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    Song YanXia

    2011-09-01

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

  3. Toll-like receptor 9 is correlated to disease activity in Chinese systemic lupus erythematosus population

    Institute of Scientific and Technical Information of China (English)

    MU Rong; SUN Xiao-yun; Lik Thai Lim; XU Chuan-hui; DAI Chen-xian; SU Yin; JIA Ru-lin; LI Zhan-guo

    2012-01-01

    Background Toll like receptor (TLR) 9 has been shown to play a crucial role in the pathogenesis of systemic lupus erythematosus (SLE) in animal models.Its pathogenic role in human SLE,however,was poorly elucidated.This study was performed to investigate the role of TLR9 involved in the aberrant signaling pathway and its correlation with disease activity in SLE.Methods mRNA level of TLR9 and interferon (IFN) regulatory factor 5 (IRF5) in peripheral blood mononuclear cells (PBMCs) were determined by real-time polymerase chain reaction (PCR).IFN-α expression was measured in the serum of the SLE patients by enzyme-linked immunosorbent assay (ELISA).Results TLR9 expression was significantly higher in SLE patients than that in health controls (P=-0.011).SLE patients with positive anti-dsDNA antibody had significantly higher expression of TLR9 than that with negative anti-dsDNA antibody (P=0.001).TLR9 expression was positively correlated with fever (P=0.017),alopecia (P=0.046),safety of estrogens in lupus erythematosus national assessment SLE disease activity index (SELENA-SLEDAI) score (rs=0.385,P=0.003),and the level of IRF5 (rs=0.35,P=0.027) and IFN-α (rs=0.627,P=0.001) in SLE patients.Conclusion TLR9 is associated with SLE disease activity and might be involved in the IFN-α pathway of SLE.

  4. Mycobacterial Signaling through Toll-like Receptors

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    Joyoti eBasu

    2012-11-01

    Full Text Available Studies over the past decade have helped to decipher molecular networks dependent on Toll-like receptor (TLR signaling, in mycobacteria-infected macrophages. Stimulation of TLRs by mycobacteria and their antigenic components rapidly induces intracellular signaling cascades involved in the activation of nuclear factor-κB and mitogen-activated protein kinase pathways, which play important roles in orchestrating proinflammatory responses and innate defense through generation of a variety of antimicrobial effector molecules. Recent studies have provided evidence that mycobacterial TLR-signaling cross talks with other intracellular antimicrobial innate pathways, the autophagy process and functional vitamin D receptor signaling. In this article we describe recent advances in the recognition, responses, and regulation of mycobacterial signaling through TLRs.

  5. Toll-like receptors in neurodegeneration

    DEFF Research Database (Denmark)

    Owens, Trevor

    2009-01-01

    Innate pattern recognition receptors are implicated in first-line defense against pathogens but also participate in maintenance of tissue homeostasis and response to injury. This chapter reviews the role of Toll-like receptors (TLRs) in neuronal and glial responses that are associated with neurod......Innate pattern recognition receptors are implicated in first-line defense against pathogens but also participate in maintenance of tissue homeostasis and response to injury. This chapter reviews the role of Toll-like receptors (TLRs) in neuronal and glial responses that are associated...... with neurodegeneration. Accompanying roles for infection and inflammation, involvement in clinical neurodegenerative disorders, and heterogeneity of glial response are discussed. A "strength of signal" hypothesis is advanced in an attempt to reconcile evolutionarily selected and therefore likely beneficial effects...

  6. Toll-like receptor 4 regulates early endothelial activation during ischemic acute kidney injury

    Science.gov (United States)

    Chen, Jianlin; John, Reji; Richardson, James A.; Shelton, John M.; Zhou, Xin J.; Wang, Yanxia; Wu, Qing Qing; Hartono, John R.; Winterberg, Pamela D.; Lu, Christopher Y.

    2012-01-01

    Ischemic acute kidney injury (AKI) triggers an inflammatory response which exacerbates injury that requires increased expression of endothelial adhesion molecules. To study this further, we used in situ hybridization, immunohistology, and isolated endothelial cells, and found increased Toll-like receptor 4 (TLR4) expression on endothelial cells of the vasa rectae of the inner stripe of the outer medulla of the kidney 4 h after reperfusion. This increase was probably due to reactive oxygen species, known to be generated early during ischemic AKI, because the addition of hydrogen peroxide increased TLR4 expression in MS1 microvascular endothelial cells in vitro. Endothelial TLR4 may regulate adhesion molecule (CD54 and CD62E) expression as they were increased on endothelia of wild-type but not TLR4 knockout mice in vivo. Further, the addition of high-mobility group protein B1, a TLR4 ligand released by injured cells, increased adhesion molecule expression on endothelia isolated from wild-type but not TLR4 knockout mice. TLR4 was localized to proximal tubules in the cortex and outer medulla after 24 h of reperfusion. Thus, at least two different cell types express TLR4, each of which contributes to renal injury by temporally different mechanisms during ischemic AKI. PMID:20927041

  7. DMPD: Toll-like receptor 3: a link between toll-like receptor, interferon and viruses. [Dynamic Macrophage Pathway CSML Database

    Lifescience Database Archive (English)

    Full Text Available 15031527 Toll-like receptor 3: a link between toll-like receptor, interferon and virus... (.csml) Show Toll-like receptor 3: a link between toll-like receptor, interferon and viruses. PubmedID 1503...1527 Title Toll-like receptor 3: a link between toll-like receptor, interferon and virus

  8. Toll-like receptors and atherosclerosis

    Directory of Open Access Journals (Sweden)

    Jerko Barbić

    2009-02-01

    Full Text Available Toll like receptors (TLR are receptors with major role in activationof immune system by regulating production of chemokinesand cytokines, which makes them important in different types ofinflammatory reactions- bacterial, viral, parasitic, acute, chronicetc. Having in mind that atherosclerosis is a chronic inflammatorydisease, it is clear then that TLRs are a group of immune systemactivators, producing specific immune cells. In human atheroscleroticplaque there is a markedly enhanced expression of TLR1,TLR2, and TLR4. TLRs are expressed in adrenal cells, and TLRagonists stimulate the release of steroids from human adrenalgland, as well. TLR2 deficient mice have an impaired steroid releaseduring endotoxemia. TLR9 stimulation leads to a corticosteroneand inflammatory cytokine response. The best characterizedof all is TLR4. Up to date this TLR has a major role in thedevelopment of atherosclerosis. Enhanced expression of hTLR4(human TLR4 in patients with ACS (acute coronary syndromewas associated with elevations of IL-12 and B7-1 expression, astypical downstream effects of TLR4 activation. It is known that acertain gene polymorphism of TLR4 can slow progression of thedisease. Over expression of TLR2 in mice facilitates ventricularremodeling after myocardial infarction. The CAPS study foundcontrary results, when in 3000 patients no connection had beenfound between TLR2 polymorphism (Arg 753 Gln,-16934A/Tand TLR4 polymorphism (D299G, T399I and the process of atherosclerosis.

  9. Toll-like receptor 8 ligands activate a vitamin D mediated autophagic response that inhibits human immunodeficiency virus type 1.

    Science.gov (United States)

    Campbell, Grant R; Spector, Stephen A

    2012-01-01

    Toll-like receptors (TLR) are important in recognizing microbial pathogens and triggering host innate immune responses, including autophagy, and in the mediation of immune activation during human immunodeficiency virus type-1 (HIV) infection. We report here that TLR8 activation in human macrophages induces the expression of the human cathelicidin microbial peptide (CAMP), the vitamin D receptor (VDR) and cytochrome P450, family 27, subfamily B, polypeptide 1 (CYP27B1), which 1α-hydroxylates the inactive form of vitamin D, 25-hydroxycholecalciferol, into its biologically active metabolite. Moreover, we demonstrate using RNA interference, chemical inhibitors and vitamin D deficient media that TLR8 agonists inhibit HIV through a vitamin D and CAMP dependent autophagic mechanism. These data support an important role for vitamin D in the control of HIV infection, and provide a biological explanation for the benefits of vitamin D. These findings also provide new insights into potential novel targets to prevent and treat HIV infection.

  10. Toll-Like Receptors in Angiogenesis

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    Karsten Grote

    2011-01-01

    Full Text Available Toll-like receptors (TLRs are known as pattern-recognition receptors related to the Toll protein of Drosophila. After recognition of pathogen-associated molecular patterns of microbial origin, the TLRs alert the immune system, and initiate innate and adaptive immune responses. The TLR system, though, is not confined solely to the leukocyte-mediated immune defense against exogenous pathogens. Besides myeloid cells, TLR expression has been reported in multiple tissues and cell types, including epithelial and endothelial cells. Moreover, despite the microbial patterns that are commonly accepted as TLR ligands, there is increasing evidence that TLRs also recognize host-derived molecules. In this regard, recent studies point to an involvement of TLRs in various chronic inflammatory disorders and cardiovascular diseases, including atherosclerosis, rheumatoid arthritis, systemic lupus erythematosus, and even cancer. A common feature of these disorders is an enhanced so-called inflammation-induced angiogenesis. However, inflammation-induced angiogenesis is not solely a key component of pathogen defense during acute infection or chronic inflammatory disorders, but also plays a critical role in repair mechanisms, e.g., wound healing and subsequent tissue regeneration. Interestingly, the latest research could coincidentally demonstrate that TLR activation promotes angiogenesis in various inflammatory settings in response to both exogenous and endogenous ligands, although the precise mode of action of TLRs in this context still remains ambiguous. The objective of this review is to present evidence for the implication of TLRs in angiogenesis during physiological and pathophysiological processes, and the potential clinical relevance for new treatment regimes involving TLR modulation.

  11. Microglia-Secreted Galectin-3 Acts as a Toll-like Receptor 4 Ligand and Contributes to Microglial Activation

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    Miguel Angel Burguillos

    2015-03-01

    Full Text Available Inflammatory response induced by microglia plays a critical role in the demise of neuronal populations in neuroinflammatory diseases. Although the role of toll-like receptor 4 (TLR4 in microglia’s inflammatory response is fully acknowledged, little is known about endogenous ligands that trigger TLR4 activation. Here, we report that galectin-3 (Gal3 released by microglia acts as an endogenous paracrine TLR4 ligand. Gal3-TLR4 interaction was further confirmed in a murine neuroinflammatory model (intranigral lipopolysaccharide [LPS] injection and in human stroke subjects. Depletion of Gal3 exerted neuroprotective and anti-inflammatory effects following global brain ischemia and in the neuroinflammatory LPS model. These results suggest that Gal3-dependent-TLR4 activation could contribute to sustained microglia activation, prolonging the inflammatory response in the brain.

  12. Activation of Toll-like Receptor-2 by Endogenous Matrix Metalloproteinase-2 Modulates Dendritic-Cell-Mediated Inflammatory Responses

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    Emmanuelle Godefroy

    2014-12-01

    Full Text Available Matrix metalloproteinase-2 (MMP-2 is involved in several physiological mechanisms, including wound healing and tumor progression. We show that MMP-2 directly stimulates dendritic cells (DCs to both upregulate OX40L on the cell surface and secrete inflammatory cytokines. The mechanism underlying DC activation includes physical association with Toll-like receptor-2 (TLR2, leading to NF-κB activation, OX40L upregulation on DCs, and ensuing TH2 differentiation. Significantly, MMP-2 polarizes T cells toward type 2 responses in vivo, in a TLR2-dependent manner. MMP-2-dependent type 2 polarization may represent a key immune regulatory mechanism for protection against a broad array of disorders, such as inflammatory, infectious, and autoimmune diseases, which can be hijacked by tumors to evade immunity.

  13. Activation of Toll-like receptor-2 by endogenous matrix metalloproteinase-2 modulates dendritic cell-mediated inflammatory responses

    Science.gov (United States)

    Godefroy, Emmanuelle; Gallois, Anne; Idoyaga, Juliana; Merad, Miriam; Tung, Navpreet; Monu, Ngozi; Saenger, Yvonne; Fu, Yichun; Nair, Rajesh; Pulendran, Bali; Jotereau, Francine; Trombetta, Sergio; Bhardwaj, Nina

    2015-01-01

    SUMMARY Matrix metalloproteinase-2 (MMP-2) is involved in several physiological mechanisms, including wound healing and tumor progression. We show that MMP-2 directly stimulates dendritic cells (DCs) to both up-regulate OX40L on the cell surface and secrete inflammatory cytokines. The mechanism underlying DC activation includes physical association with Toll-like receptor-2 (TLR2), leading to NF-κB activation, OX40L up-regulation on DCs and ensuing TH2 differentiation. Significantly, MMP-2 polarizes T cells towards type-2 responses in vivo, in a TLR2-dependent manner. MMP-2-dependent type-2 polarization may represent a key immune regulatory mechanism to protect against a broad array of disorders, such as inflammatory, infectious and autoimmune diseases, which can be hijacked by tumors to evade immunity. PMID:25466255

  14. Activation of toll-like receptor-2 by endogenous matrix metalloproteinase-2 modulates dendritic-cell-mediated inflammatory responses.

    Science.gov (United States)

    Godefroy, Emmanuelle; Gallois, Anne; Idoyaga, Juliana; Merad, Miriam; Tung, Navpreet; Monu, Ngozi; Saenger, Yvonne; Fu, Yichun; Ravindran, Rajesh; Pulendran, Bali; Jotereau, Francine; Trombetta, Sergio; Bhardwaj, Nina

    2014-12-11

    Matrix metalloproteinase-2 (MMP-2) is involved in several physiological mechanisms, including wound healing and tumor progression. We show that MMP-2 directly stimulates dendritic cells (DCs) to both upregulate OX40L on the cell surface and secrete inflammatory cytokines. The mechanism underlying DC activation includes physical association with Toll-like receptor-2 (TLR2), leading to NF-κB activation, OX40L upregulation on DCs, and ensuing TH2 differentiation. Significantly, MMP-2 polarizes T cells toward type 2 responses in vivo, in a TLR2-dependent manner. MMP-2-dependent type 2 polarization may represent a key immune regulatory mechanism for protection against a broad array of disorders, such as inflammatory, infectious, and autoimmune diseases, which can be hijacked by tumors to evade immunity.

  15. Toll-like receptor agonists in cancer therapy

    OpenAIRE

    Adams, Sylvia

    2009-01-01

    Toll-like receptors (TLRs) are pattern-recognition receptors related to the Drosophila Toll protein. TLR activation alerts the immune system to microbial products and initiates innate and adaptive immune responses. The naturally powerful immunostimulatory property of TLR agonists can be exploited for active immunotherapy against cancer. Antitumor activity has been demonstrated in several cancers, and TLR agonists are now undergoing extensive clinical investigation. This review discusses recen...

  16. Toll-Like Receptors and Myocardial Inflammation

    Directory of Open Access Journals (Sweden)

    Yan Feng

    2011-01-01

    Full Text Available Toll-like receptors (TLRs are a member of the innate immune system. TLRs detect invading pathogens through the pathogen-associated molecular patterns (PAMPs recognition and play an essential role in the host defense. TLRs can also sense a large number of endogenous molecules with the damage-associated molecular patterns (DAMPs that are produced under various injurious conditions. Animal studies of the last decade have demonstrated that TLR signaling contributes to the pathogenesis of the critical cardiac conditions, where myocardial inflammation plays a prominent role, such as ischemic myocardial injury, myocarditis, and septic cardiomyopathy. This paper reviews the animal data on (1 TLRs, TLR ligands, and the signal transduction system and (2 the important role of TLR signaling in these critical cardiac conditions.

  17. Mycoplasma lipoproteins and Toll-like receptors

    Institute of Scientific and Technical Information of China (English)

    Ling-ling ZUO; Yi-mou WU; Xiao-xing YOU

    2009-01-01

    Mycoplasmas, the smallest free-living, self-replicating bacteria with diameters of 200 to 800 nm, have been reported to be associated with human diseases. It is well known that the mycoplasma lipoprotein/peptide is able to modulate the host immune system, whose N-terminal structure is an important factor in inducing immunity and distinguishing Toll-like receptors (TLRs). However, there is still no clear elucidation about the pathogenic mechanism of mycoplasma lipoprotein/peptide and the signaling pathway. Some researchers have focused on understanding the structures of these proteins and the relationships between their structure and biological function. This review provides an update on the research in this field.

  18. Pathogen recognition by Toll-like receptor 2 activates Weibel-Palade body exocytosis in human aortic endothelial cells.

    Science.gov (United States)

    Into, Takeshi; Kanno, Yosuke; Dohkan, Jun-ichi; Nakashima, Misako; Inomata, Megumi; Shibata, Ken-ichiro; Lowenstein, Charles J; Matsushita, Kenji

    2007-03-16

    The endothelial cell-specific granule Weibel-Palade body releases vasoactive substances capable of modulating vascular inflammation. Although innate recognition of pathogens by Toll-like receptors (TLRs) is thought to play a crucial role in promotion of inflammatory responses, the molecular basis for early-phase responses of endothelial cells to bacterial pathogens has not fully been understood. We here report that human aortic endothelial cells respond to bacterial lipoteichoic acid (LTA) and synthetic bacterial lipopeptides, but not lipopolysaccharide or peptidoglycan, to induce Weibel-Palade body exocytosis, accompanied by release or externalization of the storage components von Willebrand factor and P-selectin. LTA could activate rapid Weibel-Palade body exocytosis through a TLR2- and MyD88-dependent mechanism without de novo protein synthesis. This process was at least mediated through MyD88-dependent phosphorylation and activation of phospholipase Cgamma. Moreover, LTA activated interleukin-1 receptor-associated kinase-1-dependent delayed exocytosis with de novo protein synthesis and phospholipase Cgamma-dependent activation of the NF-kappaB pathway. Increased TLR2 expression by transfection or interferon-gamma treatment increased TLR2-mediated Weibel-Palade body exocytosis, whereas reduced TLR2 expression under laminar flow decreased the response. Thus, we propose a novel role for TLR2 in induction of a primary proinflammatory event in aortic endothelial cells through Weibel-Palade body exocytosis, which may be an important step for linking innate recognition of bacterial pathogens to vascular inflammation.

  19. Apocynin inhibits Toll-like receptor-4-mediated activation of NF-κB by suppressing the Akt and mTOR pathways.

    Science.gov (United States)

    Nam, Yoon Jeong; Kim, Arum; Sohn, Dong Suep; Lee, Chung Soo

    2016-12-01

    Microbial product lipopolysaccharide has been shown to be involved in the pathogenesis of inflammatory skin diseases. Apocynin has demonstrated to have an anti-inflammatory effect. However, the effect of apocynin on the Toll-like receptor-4-dependent activation of Akt, mammalian target of rapamycin (mTOR), and nuclear factor (NF)-κB pathway, which is involved in productions of inflammatory mediators in keratinocytes, has not been studied. Using human keratinocytes, we investigated the effect of apocynin on the inflammatory mediator production in relation to the Toll-like receptor-4-mediated-Akt/mTOR and NF-κB pathways, which regulates the transcription genes involved in immune and inflammatory responses. Apocynin, Akt inhibitor SH-5, Bay 11-7085 and N-acetylcysteine each attenuated the lipopolysaccharide-induced production of cytokines, PGE2, and chemokines, changes in the levels of Toll-like receptor-4, p-Akt, mTOR, and NF-κB, and production of reactive oxygen species in keratinocytes. The results show that apocynin appears to attenuate the lipopolysaccharide-stimulated production of inflammatory mediators in keratinocytes by suppressing the Toll-like receptor-4-mediated activation of the Akt, mTOR, and NF-κB pathways. The effect of apocynin appears to be attributed to its inhibitory effect on the production of reactive oxygen species. Apocynin appears to attenuate the microbial product-mediated inflammatory skin diseases.

  20. Intestinal Serotonin Transporter Inhibition by Toll-Like Receptor 2 Activation. A Feedback Modulation

    Science.gov (United States)

    Layunta, Elena; Grasa, Laura; Castro, Marta; Pardo, Julián; Gomollón, Fernando; Mesonero, José E.

    2016-01-01

    TLR2 is a microbiota recognition receptor that has been described to contribute to intestinal homeostasis and to ameliorate inflammatory intestinal injury. In this context, serotonin (5-HT) has shown to be an essential intestinal physiological neuromodulator that is also involved in intestinal inflammatory diseases. Since the interaction between TLR2 activation and the intestinal serotoninergic system remains non-investigated, our main aim was to analyze the effect of TLR2 on intestinal serotonin transporter (SERT) activity and expression and the intracellular pathways involved. Caco-2/TC7 cells were used to analyze SERT and TLR2 molecular expression and SERT activity by measuring 5-HT uptake. The results showed that apical TLR2 activation inhibits SERT activity in Caco-2/TC7 cells mainly by reducing SERT protein level either in the plasma membrane, after short-term TLR2 activation or in both the plasma membrane and cell lysate, after long-term activation. cAMP/PKA pathway appears to mediate short-term inhibitory effect of TLR2 on SERT; however, p38 MAPK pathway has been shown to be involved in both short- and long-term TLR2 effect. Reciprocally, 5-HT long-term treatment yielded TLR2 down regulation in Caco-2/TC7 cells. Finally, results from in vivo showed an augmented intestinal SERT expression in mice Tlr2-/-, thus confirming our inhibitory effect of TLR2 on intestinal SERT in vitro. The present work infers that TLR2 may act in intestinal pathophysiology, not only by its inherent innate immune role, but also by regulating the intestinal serotoninergic system. PMID:28033388

  1. Toll-like receptor activation enhances cell-mediated immunity induced by an antibody vaccine targeting human dendritic cells

    Directory of Open Access Journals (Sweden)

    Berger Marc A

    2007-01-01

    Full Text Available Abstract Previously, we have successfully targeted the mannose receptor (MR expressed on monocyte-derived dendritic cells (DCs using a fully human MR-specific antibody, B11, as a vehicle to deliver whole protein tumor antigens such as the human chorionic gonadotropin hormone (hCGβ. Since MRs play a role in bridging innate immunity with adaptive immunity we have explored several toll-like receptor (TLR-specific ligands that may synergize with MR targeting and be applicable as adjuvants in the clinic. We demonstrate that antigen-specific helper and cytolytic T cells from both healthy donors and cancer patients were effectively primed with B11-hCGβ-treated autologous DCs when a combination of one or several TLR ligands is used. Specifically, concomitant signaling of DCs via TLR3 with dsRNA (poly I:C and DC TLR 7/8 with Resiquimod (R-848, respectively, elicited efficient antigen presentation-mediated by MR-targeting. We demonstrate that MR and TLRs contribute towards maturation and activation of DCs by a mechanism that may be driven by a combination of adjuvant and antibody vaccines that specifically deliver antigenic targets to DCs.

  2. Toll-like Receptors and Prostate Cancer

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    Shu eZhao

    2014-07-01

    Full Text Available Prostate cancer is the second leading cause of cancer-related death in men after lung cancer. Immune responses clearly play a critical role in the tumorigenesis and in the efficacy of radiation therapy and chemotherapy in prostate cancer; however, the underlying molecular mechanisms are still poorly understood. Toll-like receptors (TLRs are a well-known family of pattern recognition receptors that play a key role in host immune system. Recent studies demonstrate that there are links between TLRs and cancer; however, the function and biological importance of TLRs in prostate cancer seems complex. To elucidate the role of TLRs and innate immunity in prostate cancer might provide us with a better understanding of the molecular mechanisms of this disease. Moreover, utilizing the agonists or antagonists of TLRs might represent a promising new strategy against prostate cancer. In this review, we summarize recent advances on the studies of association between TLR signaling and prostate cancer, TLR polymorphisms and prostate cancer risk, and provide some insights about TLRs as potential targets for prostate cancer immunotherapy.

  3. The Novel Toll-Like Receptor 2 Agonist SUP3 Enhances Antigen Presentation and T Cell Activation by Dendritic Cells

    Science.gov (United States)

    Guo, Xueheng; Wu, Ning; Shang, Yingli; Liu, Xin; Wu, Tao; Zhou, Yifan; Liu, Xin; Huang, Jiaoyan; Liao, Xuebin; Wu, Li

    2017-01-01

    Dendritic cells (DCs) are highly specialized antigen-presenting cells that play crucial roles in innate and adaptive immunity. Previous studies suggested that Toll-like receptor (TLR) agonists could be used as potential adjuvants, as activation of TLRs can boost DC-induced immune responses. TLR2 agonists have been shown to enhance DC-mediated immune responses. However, classical TLR2 agonists such as Pam3CSK4 are not stable enough in vivo, which limits their clinical applications. In this study, a novel structurally stable TLR2 agonist named SUP3 was designed. Functional analysis showed that SUP3 induced much stronger antitumor response than Pam3CSK4 by promoting cytotoxic T lymphocytes activation in vivo. This effect was achieved through the following mechanisms: SUP3 strongly enhanced the ability of antigen cross-presentation by DCs and subsequent T cell activation. SUP3 upregulated the expression of costimulatory molecules on DCs and increased antigen deposition in draining lymph nodes. More interestingly, SUP3 induced less amount of pro-inflammatory cytokine production in vivo compared to other TLR agonists such as lipopolysaccharide. Taken together, SUP3 could serve as a novel promising immune adjuvant in vaccine development and immune modulations.

  4. MR imaging and T2 measurements in peripheral nerve repair with activation of Toll-like receptor 4 of neurotmesis

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Xiang; Zhang, Fang; Lu, Liejing; Li, Haojiang; Wen, Xuehua; Shen, Jun [Sun Yat-Sen University, Department of Radiology, Sun Yat-Sen Memorial Hospital, Guangzhou, Guangdong (China)

    2014-05-15

    To investigate the role of MR imaging in neurotmesis combined with surgical repair and Toll-like receptor 4 (TLR4) activation. Forty-eight rats received subepineurial microinjection of the TLR4 agonist lipopolysaccharide (LPS, n = 24) or phosphate buffered saline (PBS, n = 24) immediately after surgical repair of the transected sciatic nerve. Sequential fat-suppressed T2-weighted imaging and quantitative T2 measurements were obtained at 3, 7, 14 and 21 days after surgery, with histologic assessments performed at regular intervals. T2 relaxation times and histological quantification of the distal stumps were measured and compared. The distal stumps of transected nerves treated with LPS or PBS both showed persistent enlargement and hyperintense signal. T2 values of the distal stumps showed a rapid rise to peak level followed by a rapid decline pattern in nerves treated with LPS, while exhibiting a slow rise to peak value followed by a slow decline in nerves treated with PBS. Nerves treated with LPS exhibited more prominent macrophage recruitment, faster myelin debris clearance and more pronounced nerve regeneration. Nerves treated with TLR4 activation had a characteristic pattern of T2 value change over time. Longitudinal T2 measurements can be used to detect the enhanced repair effect associated with TLR4 activation in the surgical repair of neurotmesis. (orig.)

  5. Synergistic activation of inflammatory cytokine genes by interferon-γ-induced chromatin remodeling and toll-like receptor signaling.

    Science.gov (United States)

    Qiao, Yu; Giannopoulou, Eugenia G; Chan, Chun Hin; Park, Sung-Ho; Gong, Shiaoching; Chen, Janice; Hu, Xiaoyu; Elemento, Olivier; Ivashkiv, Lionel B

    2013-09-19

    Synergistic activation of inflammatory cytokine genes by interferon-γ (IFN-γ) and Toll-like receptor (TLR) signaling is important for innate immunity and inflammatory disease pathogenesis. Enhancement of TLR signaling, a previously proposed mechanism, is insufficient to explain strong synergistic activation of cytokine production in human macrophages. Rather, we found that IFN-γ induced sustained occupancy of transcription factors STAT1, IRF-1, and associated histone acetylation at promoters and enhancers at the TNF, IL6, and IL12B loci. This priming of chromatin did not activate transcription but greatly increased and prolonged recruitment of TLR4-induced transcription factors and RNA polymerase II to gene promoters and enhancers. Priming sensitized cytokine transcription to suppression by Jak inhibitors. Genome-wide analysis revealed pervasive priming of regulatory elements by IFN-γ and linked coordinate priming of promoters and enhancers with synergistic induction of transcription. Our results provide a synergy mechanism whereby IFN-γ creates a primed chromatin environment to augment TLR-induced gene transcription.

  6. CBLB502, an agonist of Toll-like receptor 5, has antioxidant and scavenging free radicals activities in vitro.

    Science.gov (United States)

    Li, Weiguang; Ge, Changhui; Yang, Liu; Wang, Ruixue; Lu, Yiming; Gao, Yan; Li, Zhihui; Wu, Yonghong; Zheng, Xiaofei; Wang, Zhaoyan; Zhang, Chenggang

    2016-01-01

    The bacterial protein flagellin is the known agonist of Toll-like receptor 5 (TLR5). It has been reported that CBLB502, a novel agonist of TLR5 derived from Salmonella flagellin, could reduce radiation toxicity in mouse and primate models, protect mice from dermatitis and oral mucositis caused by radiation, inhibit acute renal ischemic failure, and inhibit the growth of A549 lung cancer cell. The property of CBLB502 is able to bind to TLR5 and activates NF-κB signaling. In this study, we investigated the antioxidant potential and free radicals scavenging properties of CBLB502 in vitro. Interestingly, we found that CBLB502 has a direct and distinct antioxidant capacity and can efficiently scavenge a variety of free radicals, including superoxide anion, hydroxyl radical, and ABTS cation (ABTS(+)). Through wave scanning and kinetic evaluation of scavenging ABTS(+), we found that the ABTS(+) scavenging process of CBLB502 is relatively slow, and the ABTS(+) scavenging activity of CBLB502 has a consistently kinetics characteristics. In conclusion, our results suggested that CBLB502 has antioxidant and scavenging free radicals activities in vitro. It is implied that CBLB502 might partially promote the beneficial protective effect through its scavenging free radicals.

  7. Apolipoprotein E inhibits toll-like receptor (TLR)-3- and TLR-4-mediated macrophage activation through distinct mechanisms.

    Science.gov (United States)

    Zhu, Yanjuan; Kodvawala, Ahmer; Hui, David Y

    2010-04-28

    Previous studies have shown that apoE (apolipoprotein E) expression in macrophages suppresses inflammatory responses; however, whether endogenously synthesized apoE acts intracellularly or after its secretion in suppressing macrophage inflammation remains unclear. The present study used the murine monocyte macrophage cell line RAW 264.7 to examine the influence of exogenous apoE on macrophage inflammatory responses induced by TLR (Toll-like receptor)-4 and TLR-3 agonists LPS (lipopolysaccharide) and poly(I-C) respectively. Results showed that exogenously added apoE suppressed the LPS and poly(I-C) induction of IL (interleukin)-6, IL-1beta and TNF-alpha (tumour necrosis factor-alpha) secretion by RAW 264.7 cells. The mechanism was related to apoE suppression of TLR-agonist-induced phosphorylation of JNK (c-Jun N-terminal kinase) and c-Jun. A peptide containing the tandem repeat sequence of the receptor-binding domain of apoE, apoE-(141-155)2, was similarly effective in inhibiting LPS- and poly(I-C)-induced macrophage inflammatory responses. Reductive methylation of lysine residues in apoE, which abolished its receptor-binding capability without affecting its ability to interact with HSPGs (heparin sulfate proteoglycans), inhibited the ability of apoE to suppress macrophage responses to LPS, but had no effect on apoE suppression of poly(I-C)-induced macrophage activation. The ability of apoE to suppress poly(I-C)-induced pro-inflammatory cytokine production was abolished by heparinase treatment of RAW 264.7 cells to remove cell-surface HSPGs. Taken together, these results indicate that exogenous apoE inhibits macrophage inflammatory responses to TLR-4 and TLR-3 agonists through distinct mechanisms related to receptor and HSPG binding respectively, and that these inhibitory effects converged on suppression of JNK and c-Jun activation which are necessary for macrophage activation.

  8. Lubricin/Proteoglycan 4 binds to and regulates the activity of Toll-Like Receptors In Vitro.

    Science.gov (United States)

    Iqbal, S M; Leonard, C; Regmi, S C; De Rantere, D; Tailor, P; Ren, G; Ishida, H; Hsu, Cy; Abubacker, S; Pang, D Sj; Salo, P T; Vogel, H J; Hart, D A; Waterhouse, C C; Jay, G D; Schmidt, T A; Krawetz, R J

    2016-01-01

    Proteoglycan 4 (PRG4/lubricin) is secreted by cells that reside in articular cartilage and line the synovial joint. Lubricin may play a role in modulating inflammatory responses through interaction with CD44. This led us to examine if lubricin could be playing a larger role in the modulation of inflammation/immunity through interaction with Toll-like receptors (TLRs). Human Embryonic Kidney (HEK) cells overexpressing TLRs 2, 4 or 5 and surface plasmon resonance were employed to determine if full length recombinant human lubricin was able to bind to and activate TLRs. Primary human synovial fibroblasts were also examined using flow cytometry and Luminex multiplex ELISA. A rat destabilization model of osteoarthritis (OA) was used to determine if lubricin injections were able to regulate pain and/or inflammation in vivo. Lubricin can bind to and regulate the activity of TLRs, leading to downstream changes in inflammatory signalling independent of HA. We confirmed these findings in vivo through intra-articular injections of lubricin in a rat OA model where the inhibition of systemic inflammatory signaling and reduction in pain were observed. Lubricin plays an important role in regulating the inflammatory environment under both homeostatic and tissue injury states.

  9. Toll-like receptors of deuterostome invertebrates

    Directory of Open Access Journals (Sweden)

    Honoo eSatake

    2012-02-01

    Full Text Available Defensive systems against pathogens are responsible not only for survival or lifetime of an individual but also for the evolution of a species. Innate immunity is expected to be more important for invertebrates than mammals, given that adaptive immunity has not been acquired in the former. Toll-like receptors (TLRs have been shown to play a crucial role in host defense of pathogenic microbes in innate immunity of mammals. Recent genome-wide analyses have suggested that TLR or their related genes are conserved in invertebrates. In particular, numerous TLR-related gene candidates were detected in deuterostome invertebrates including a sea urchin (222 TLR-related gene candidates and amphioxus (72 TLR-related gene candidates. Molecular phylogenetic analysis verified that most of sea urchin or amphioxus TLR candidates are paralogous, suggesting that these organisms expanded TLR-related genes in a species-specific manner. In contrast, another deuterostome invertebrate, an ascidian, Ciona intestinalis, was found to possess only two TLR genes. Moreover, Ciona TLRs, Ci-TLR1 and -2, were shown to possess hybrid functionality of mammalian TLRs. Such functionality of Ci-TLRs could not be predicted by sequence comparison with vertebrate TLRs, indicating the confounding evolutionary lineages of deuterostome invertebrate TLRs or their candidates. In this review article, we present recent advances in studies of TLRs or their candidates of deuterostome invertebrates, and provide insight into an evolutionary process of TLRs.

  10. Mite allergen Der-p2 triggers human B lymphocyte activation and Toll-like receptor-4 induction.

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    Jaw Ji Tsai

    Full Text Available BACKGROUND: Allergic disease can be characterized as manifestations of an exaggerated inflammatory response to environmental allergens triggers. Mite allergen Der-p2 is one of the major allergens of the house dust mite, which contributes to TLR4 expression and function in B cells in allergic patients. However, the precise mechanisms of Der-p2 on B cells remain obscure. METHODOLOGY/PRINCIPAL FINDINGS: We investigated the effects of Der-p2 on proinflammatory cytokines responses and Toll-like receptor-4 (TLR4-related signaling in human B cells activation. We demonstrated that Der-p2 activates pro-inflammatory cytokines, TLR4 and its co-receptor MD2. ERK inhibitor PD98059 significantly enhanced TLR4/MD2 expression in Der-p2-treated B cells. Der-p2 markedly activated mitogen-activated protein kinase (MAPK phosphatase-1 (MKP-1 and decreased p38 phosphorylation in B cells. MKP-1-siRNA downregulated TLR4/MD2 expression in Der-p2-treated B cells. In addition, Der-p2 significantly up-regulated expression of co-stimulatory molecules and increased B cell proliferation. Neutralizing Der-p2 antibody could effectively abrogate the Der-p2-induced B cell proliferation. Der-p2 could also markedly induce NF-κB activation in B cells, which could be counteracted by dexamethasone. CONCLUSIONS/SIGNIFICANCE: These results strongly suggest that Der-p2 is capable of triggering B cell activation and MKP-1-activated p38/MAPK dephosphorylation-regulated TLR4 induction, which subsequently enhances host immune, defense responses and development of effective allergic disease therapeutics in B cells.

  11. Toll-like receptor 2 or toll-like receptor 4 deficiency does not modify lupus in MRLlpr mice.

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    Simon J Freeley

    Full Text Available Systemic lupus erythematosus is an autoimmune disease with a high morbidity and nephritis is a common manifestation. Previous studies in murine lupus models have suggest a role for Toll-like receptor 2 and 4. We examined the role of these molecules in MRL lpr mice which is one of the most established and robust murine models. We compared disease parameters in Toll-like receptor 2 or Toll-like receptor 4 deficient mice with their littermate controls. We found no difference in the severity of glomerulonephritis as assessed by histology, serum creatinine and albuminuria when Toll-like receptor 2 or Toll-like receptor 4 deficient MRLlpr mice were compared with Toll-like receptor sufficient controls. We also found similar levels of anti-dsDNA and anti-ssDNA antibodies. These results show that Toll-like receptor 2 and Toll-like receptor 4 do not play a significant role in MRLlpr mice, and therefore they may not be important in human lupus.

  12. Prenatal Activation of Toll-Like Receptor-4 Dampens Adult Hippocampal Neurogenesis in An IL-6 Dependent Manner

    Science.gov (United States)

    Mouihate, Abdeslam

    2016-01-01

    Prenatal immune challenge has been associated with alteration in brain development and plasticity that last into adulthood. We have previously shown that prenatal activation of toll-like receptor 4 by lipopolysaccharide (LPS) induces IL-6-dependent STAT-3 signaling pathway in the fetal brain. Whether this IL-6-dependent activation of fetal brain results in long lasting impact in brain plasticity is still unknown. Furthermore, it has been shown that prenatal LPS heightens the hypothalamic–pituitary–adrenal (HPA) response in adulthood. In the present study we tested whether LPS administration during pregnancy affects neurogenesis in adult male offspring. Because corticosterone, the end-product of HPA axis activity in rats, alters neurogenesis we tested whether this enhanced HPA axis responsiveness in adult male offspring played a role in the long lasting impact of LPS on neurogenesis during adulthood. Pregnant rats were given either LPS, or LPS and an IL-6 neutralizing antibody (IL-6Ab). The newly born neurons were monitored in the subventricular zone (SVZ) and the dentate gyrus (DG) of the hippocampus of adult male offspring by monitoring doublecortin and T-box brain protein-2 expression: two well-established markers of newly born neurons. Prenatal LPS decreased the number of newly born neurons in the DG, but not in the SVZ of adult offspring. This decreased number of newly born neurons in the DG was absent when IL-6Ab was co-injected with LPS during pregnancy. Furthermore, administration of a corticosterone receptor blocker, RU-486, to adult offspring blunted the prenatal LPS induced decrease in newly born neurons in the DG. These data suggest that maternally triggered IL-6 plays a crucial role in the long lasting impact of LPS on adult neurogenesis. PMID:27445700

  13. Activation of the human immune system via toll-like receptors by the oncolytic parvovirus H-1.

    Science.gov (United States)

    Sieben, Maike; Schäfer, Petra; Dinsart, Christiane; Galle, Peter R; Moehler, Markus

    2013-06-01

    This study aimed to investigate the function of toll-like receptors (TLRs) during oncolytic parvovirus H-1 (H-1PV)-induced human immune responses. First, the role of TLRs in the activation of the NFκB transcription factor was characterized; second, the immunologic effects of H-1PV-induced tumor cell lysates (TCL) on human antitumor immune responses were evaluated. A human ex vivo model was used to study immune responses with dendritic cells (DCs). Human embryonic kidney cells (HEK293) transfected to stably express TLRs were used as potential human DC equivalents to further investigate the role of specific TLRs during immune activation. TLR3 and TLR9 were activated by H-1PV infection, which correlated with NFκB translocation to the nucleus and a reduced cytoplasmic IκB expression. Using a TLR-signaling reporter plasmid (pNiFty-Luc), NFκB activity was increased following H-1PV infection. In addition, human DCs coincubated with H-1PV-induced TCL demonstrated increased TLR3 and TLR9 expression. These data suggest that H-1PV-induced TCL stimulate human DCs at least in part through TLR-dependent signaling pathways. Thus, DC maturation occurred through exposure to H-1PV-induced TCL through TLR-signaling leading to NFκB-dependent activation of the adaptive immune system as indicated by the increased expression of CD86, TLR3 and TLR9. Furthermore, the transcription of various cytokines indicates the activation of immune response, therefore the production of the proinflammatory cytokine TNF-α was determined. Here, H-1PV-induced TCL significantly enhanced the TNF-α level by DCs after coculture. H-1PV oncolytic virotherapy enhances immune priming by different effects on DCs and generates antitumor immunity. These findings potentially offer a new approach to tumor therapy.

  14. Lipid IVa incompletely activates MyD88-independent Toll-like receptor 4 signaling in mouse macrophage cell lines.

    Science.gov (United States)

    Ogura, Norihiko; Muroi, Masashi; Sugiura, Yuka; Tanamoto, Ken-ichi

    2013-04-01

    We investigated the difference in the effect of synthetic lipid A compounds on MyD88-dependent and -independent Toll-like receptor 4 (TLR4) signaling in mouse macrophage cells. At higher concentrations, Escherichia coli-type hexa-acylated lipid A 506, Salmonella-type hepta-acylated lipid A 516, the lipid A precursor lipid IVa and monophosphoryl lipid A induced similar levels of production of the MyD88-dependent cytokine IL-1β although their potencies varied, whereas the maximum production of the MyD88-independent cytokine RANTES induced by lipid IVa was less than 50% that of other lipid A compounds. A maximum level of NF-κB activation, which is involved in IL-1β gene transcription, was also induced to a similar level by these four lipid A compounds, while the maximum level of IFN-β promoter activity induced during MyD88-independent signaling was also less than 50% for lipid IVa stimulation compared with other lipid A compounds. Early IκBα phosphorylation activated by MyD88-dependent signaling was similarly induced by 506 and lipid IVa, whereas lipid IVa barely stimulated the phosphorylation of IRF3, a MyD88-independent transcription factor, although efficient phosphorylation was observed with 506 stimulation. These results indicate that lipid IVa has limited activity toward MyD88-independent signaling of TLR4, in macrophage cell lines, despite having efficient activity in the MyD88-dependent pathway.

  15. Differential cell reaction upon Toll-like receptor 4 and 9 activation in human alveolar and lung interstitial macrophages

    Directory of Open Access Journals (Sweden)

    Meyerhans Andreas

    2010-09-01

    Full Text Available Abstract Background Investigations on pulmonary macrophages (MΦ mostly focus on alveolar MΦ (AM as a well-defined cell population. Characteristics of MΦ in the interstitium, referred to as lung interstitial MΦ (IM, are rather ill-defined. In this study we therefore aimed to elucidate differences between AM and IM obtained from human lung tissue. Methods Human AM and IM were isolated from human non-tumor lung tissue from patients undergoing lung resection. Cell morphology was visualized using either light, electron or confocal microscopy. Phagocytic activity was analyzed by flow cytometry as well as confocal microscopy. Surface marker expression was measured by flow cytometry. Toll-like receptor (TLR expression patterns as well as cytokine expression upon TLR4 or TLR9 stimulation were assessed by real time RT-PCR and cytokine protein production was measured using a fluorescent bead-based immunoassay. Results IM were found to be smaller and morphologically more heterogeneous than AM, whereas phagocytic activity was similar in both cell types. HLA-DR expression was markedly higher in IM compared to AM. Although analysis of TLR expression profiles revealed no differences between the two cell populations, AM and IM clearly varied in cell reaction upon activation. Both MΦ populations were markedly activated by LPS as well as DNA isolated from attenuated mycobacterial strains (M. bovis H37Ra and BCG. Whereas AM expressed higher amounts of inflammatory cytokines upon activation, IM were more efficient in producing immunoregulatory cytokines, such as IL10, IL1ra, and IL6. Conclusion AM appear to be more effective as a non-specific first line of defence against inhaled pathogens, whereas IM show a more pronounced regulatory function. These dissimilarities should be taken into consideration in future studies on the role of human lung MΦ in the inflammatory response.

  16. Lactobacilli inhibit interleukin-8 production induced by Helicobacter pylori lipopolysaccharide-activated Toll-like receptor 4

    Institute of Scientific and Technical Information of China (English)

    Chao Zhou; Feng-Zhen Ma; Xue-Jie Deng; Hong Yuan; Hong-Sheng Ma

    2008-01-01

    AIM: To investigate the effect of Lactobacillus bulgaricus (LBG) on the Toll-like receptor 4 (TLR4) pathway and interleukin-8 (IL-8) production in SGC-7901 cells treated with Helicobacter pyloriSydney strain 1 lipopolysaccharide (H pyloriSS1-LPS).METHODS: SGC-7901 cells were treated with H pyIoriSS1-LPS in the presence or absence of pretreatment for 1 h with viable LBG or supematant recovered from LBG culture MRS broth (LBG-s). Cellular lysates were prepared for Western blot with anti-TLR4,anti-transforming growth factor β-activated kinase 1 (TAK1), anti-phospho-TAK1, anti-nuclear factor κB (NF-κB), anti-p38 mitogen-activated protein kinase (p38MAPK), and anti-phospho-p38MAPK antibodies.The amount of IL-8 in cell culture medium was measured by ELISA.RESULTS: H pyloriSS1-LPS up-regulated the expression of TLR4, stimulated the phosphorylation of TAK1, subsequently enhanced the activation of NFκB and the phosphorylation of p38MAPK in a timedependent manner, leading to augmentation of IL-8 production in SGC-7901 cells. Viable LBG or LBG-s pretreatment attenuated the expression of TLR4,inhibited the phosphorylation of TAK1 and p38MAPK,prevented the activation of NF-κB, and consequently blocked IL-8 production.CONCLUSION: H pyloriSS1-LPS induces IL-8production through activating TLR4 signaling in SGC-7901 cells and viable LBG or LBG-s prevents H pyloriSS1-LPS-mediated IL-8 production via inhibition of the TLR4 pathway.

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

    Science.gov (United States)

    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.

  18. Wheat amylase trypsin inhibitors drive intestinal inflammation via activation of toll-like receptor 4.

    Science.gov (United States)

    Junker, Yvonne; Zeissig, Sebastian; Kim, Seong-Jun; Barisani, Donatella; Wieser, Herbert; Leffler, Daniel A; Zevallos, Victor; Libermann, Towia A; Dillon, Simon; Freitag, Tobias L; Kelly, Ciaran P; Schuppan, Detlef

    2012-12-17

    Ingestion of wheat, barley, or rye triggers small intestinal inflammation in patients with celiac disease. Specifically, the storage proteins of these cereals (gluten) elicit an adaptive Th1-mediated immune response in individuals carrying HLA-DQ2 or HLA-DQ8 as major genetic predisposition. This well-defined role of adaptive immunity contrasts with an ill-defined component of innate immunity in celiac disease. We identify the α-amylase/trypsin inhibitors (ATIs) CM3 and 0.19, pest resistance molecules in wheat, as strong activators of innate immune responses in monocytes, macrophages, and dendritic cells. ATIs engage the TLR4-MD2-CD14 complex and lead to up-regulation of maturation markers and elicit release of proinflammatory cytokines in cells from celiac and nonceliac patients and in celiac patients' biopsies. Mice deficient in TLR4 or TLR4 signaling are protected from intestinal and systemic immune responses upon oral challenge with ATIs. These findings define cereal ATIs as novel contributors to celiac disease. Moreover, ATIs may fuel inflammation and immune reactions in other intestinal and nonintestinal immune disorders.

  19. Toll-like receptor 2 and 4 induced interleukin-19 dampens immune reactions and associates inversely with spondyloarthritis disease activity.

    Science.gov (United States)

    Kragstrup, T W; Andersen, T; Holm, C; Schiøttz-Christensen, B; Jurik, A G; Hvid, M; Deleuran, B

    2015-05-01

    Spondyloarthritis (SpA) is a group of immune mediated inflammatory diseases affecting joints, gut, skin and entheses. The inflammatory process involves activation of Toll-like receptor (TLR)-2 and TLR-4 and production of cytokines and chemokines such as monocyte chemoattractant protein 1 (CCL2/MCP-1). This proinflammatory chemokine recruits monocytes to sites of inflammation and is central in the development of several immune-mediated inflammatory diseases. Interleukin (IL)-19 is a member of the IL-10 family of cytokines. IL-19-deficient mice are more susceptible to innate-mediated colitis and develop more severe inflammation in response to injury. In this work, we studied inducers of IL-19 production and effect of IL-19 on the production of CCL2/MCP-1 and proinflammatory cytokines in peripheral blood mononuclear cells (PBMCs) from healthy controls (HCs) and in PBMCs and synovial fluid mononuclear cells (SFMCs) from SpA patients. Further, we measured IL-19 in plasma from HCs and in plasma and synovial fluid from SpA patients. Constitutive IL-19 expression was present in both PBMCs and SFMCs and the secretion of IL-19 was increased by TLR-2 and TLR-4 ligands. Neutralizing IL-19 in HC PBMCs and SpA SFMCs resulted in increased production of CCL-2/MCP-1. IL-19 concentrations were decreased in synovial fluid compared with plasma and associated inversely with disease activity in SpA. SpA SFMCs produced less IL-19 in response to LPS compared with HC PBMCs. These findings indicate that IL-19 production is diminished in SpA. Taken together, impaired IL-19 control of the innate immune system might be involved in the pathogenesis of SpA.

  20. Impaired toll like receptor-7 and 9 induced immune activation in chronic spinal cord injured patients contributes to immune dysfunction

    Science.gov (United States)

    Gungor, Bilgi; Kahraman, Tamer; Gursel, Mayda; Yilmaz, Bilge

    2017-01-01

    Reduced immune activation or immunosuppression is seen in patients withneurological diseases. Urinary and respiratory infections mainly manifested as septicemia and pneumonia are the most frequent complications following spinal cord injuries and they account for the majority of deaths. The underlying reason of these losses is believed to arise due to impaired immune responses to pathogens. Here, we hypothesized that susceptibility to infections of chronic spinal cord injured (SCI) patients might be due to impairment in recognition of pathogen associated molecular patterns and subsequently declining innate and adaptive immune responses that lead to immune dysfunction. We tested our hypothesis on healthy and chronic SCI patients with a level of injury above T-6. Donor PBMCs were isolated and stimulated with different toll like receptor ligands and T-cell inducers aiming to investigate whether chronic SCI patients display differential immune activation to multiple innate and adaptive immune cell stimulants. We demonstrate that SCI patients' B-cell and plasmacytoid dendritic cells retain their functionality in response to TLR7 and TLR9 ligand stimulation as they secreted similar levels of IL6 and IFNα. The immune dysfunction is not probably due to impaired T-cell function, since neither CD4+ T-cell dependent IFNγ producing cell number nor IL10 producing regulatory T-cells resulted different outcomes in response to PMA-Ionomycin and PHA-LPS stimulation, respectively. We showed that TLR7 dependent IFNγ and IP10 levels and TLR9 mediated APC function reduced substantially in SCI patients compared to healthy subjects. More importantly, IP10 producing monocytes were significantly fewer compared to healthy subjects in response to TLR7 and TLR9 stimulation of SCI PBMCs. When taken together this work implicated that these defects could contribute to persistent complications due to increased susceptibility to infections of chronic SCI patients. PMID:28170444

  1. Toll-like receptors:function and roles in asthma

    Institute of Scientific and Technical Information of China (English)

    周林福; 殷凯生

    2004-01-01

    @@ Asthma is a chronic airway inflammatory disease involved with multiple susceptible genes for atopy. Toll-like receptors (TLRs), an ancient though newly characterized and evolutionarily conserved immune receptor family, activate the mononuclear phagocyte system via both myeloid differentiation marker 88 (MyD88)-dependent and -independent signaling pathways. TLRs might play a key role in asthma by recognition of pathogenic microorganisms, activation of innate immunity, regulation of adaptive immunity, and induction of immune tolerance. For future immunotherapy of asthma, it is promising to develop novel immune regulators by selectively targeting blockade of TLRs.

  2. Silencing of renal DNaseI in murine lupus nephritis imposes exposure of large chromatin fragments and activation of Toll like receptors and the Clec4e

    DEFF Research Database (Denmark)

    Thiyagarajan, Dhivya; Fismen, Silje; Seredkina, Natalya;

    2012-01-01

    levels of DNaseI, Toll like receptors 7-9, Clec4e, pro-inflammatory cytokines and MMP2/MMP9 were determined and compared with in situ protein expression profiles and clinical data. We demonstrate that exposure of chromatin significantly up-regulate Toll like receptors and Clec4e in mice, and also...

  3. Regulation of Toll-like receptor signaling in innate immunity

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Toll-like receptors sense invading pathogens by recognizing a wide variety of conserved pathogen-associated molecular patterns(PAMPs).The members of the TLR family selectively utilize adaptor proteins MyD88,TRIF,TIRAP and TRAM to activate overlapping but distinct signal transduction pathways which trigger production of different panels of mediators such as proinflammatory cytokines and type I interferon.These mediators not only control innate immunity but also direct subsequently developed adaptive immunity.TLR activation is strictly and finely regulated at multiple levels of the signal transduction pathways.

  4. Plasma membrane Toll-like receptor activation increases bacterial uptake but abrogates endosomal Lactobacillus acidophilus induction of interferon-β

    DEFF Research Database (Denmark)

    Boye, Louise; Welsby, Iain; Lund, Lisbeth Drozd

    2016-01-01

    Lactobacillus acidophilus induces a potent interferon-β (IFN-β) response in dendritic cells (DCs) by a Toll-like receptor 2 (TLR2) -dependent mechanism, in turn leading to strong interleukin-12 (IL-12) production. In the present study, we investigated the involvement of different types...... of endocytosis in the L. acidophilus-induced IFN-β and IL-12 responses and how TLR2 or TLR4 ligation by lipopolysaccharide and Pam3/4CSK4 influenced endocytosis of L. acidophilus and the induced IFN-β and IL-12 production. Lactobacillus acidophilus was endocytosed by constitutive macropinocytosis taking place....... acidophilus enhanced the uptake of the bacteria. However, in these experimental conditions, induction of IFN-β and IL-12 was strongly inhibited. As L. acidophilus-induced IFN-β depends on endocytosis and endosomal degradation before signalling and as TLR stimulation from the plasma membrane leading...

  5. Clinical Effects of a Topically Applied Toll-like Receptor 9 Agonist in Active Moderate-to-Severe Ulcerative Colitis

    Science.gov (United States)

    Atreya, Raja; Bloom, Stuart; Scaldaferri, Franco; Gerardi, Viviana; Admyre, Charlotte; Karlsson, Åsa; Knittel, Thomas; Kowalski, Jan; Lukas, Milan; Löfberg, Robert; Nancey, Stephane; Petryka, Robert; Rydzewska, Grazyna; Schnabel, Robert; Seidler, Ursula; Neurath, Markus F.

    2016-01-01

    Background and Aims: Toll-like receptors [TLRs] are potential drug targets for immunomodulation. We determined the safety and efficacy of the TLR-9 agonist DNA-based immunomodulatory sequence 0150 [DIMS0150] in ulcerative colitis [UC] patients refractory to standard therapy. Methods: In this randomized, double-blind, placebo-controlled trial, 131 patients with moderate-to-severe active UC were randomized to receive two single doses of the oligonucleotide DIMS0150 [30 mg] or placebo administered topically during lower GI endoscopy at baseline and Week 4. The primary endpoint was clinical remission, defined as Clinical Activity Index [CAI] ≤4, at Week 12. Secondary endpoints included mucosal healing and symptomatic remission of key patient-reported outcomes [absence of blood in stool and weekly stool frequency <35]. Results: There was no statistical significant difference between the groups in the induction of clinical remission at Week 12, with 44.4% in the DIMS0150 group vs. 46.5% in the placebo group. However, the proportion of patients who achieved symptomatic remission was 32.1% in the DIMS0150 group vs. 14.0% in the placebo group at Week 4 [p = 0.020], and 44.4% vs. 27.9% at Week 8 [p = 0.061]. More patients on DIMS0150 compared with those on placebo had mucosal healing [34.6% vs. 18.6%; p = 0.09] and histological improvement regarding the Geboes score [30.9% vs. 9.3%; p = 0.0073] at Week 4. Significantly more patients on DIMS0150 were in clinical remission with mucosal healing at Week 4: 21% vs. 4.7% in the placebo group [p = 0.02]. DIMS0150 was well tolerated, and no safety signals compared with placebo were evident. Conclusions: Therapy with the topically applied TLR-9 agonist DIMS0150 is a promising and well-tolerated novel therapeutic option for treatment-refractory, chronic active UC patients, warranting further clinical trials. PMID:27208386

  6. Mannan-binding lectin inhibits Candida albicans-induced cellular responses in PMA-activated THP-1 cells through Toll-like receptor 2 and Toll-like receptor 4.

    Directory of Open Access Journals (Sweden)

    Mingyong Wang

    Full Text Available BACKGROUND: Candida albicans (C. albicans, the most common human fungal pathogen, can cause fatal systemic infections under certain circumstances. Mannan-binding lectin (MBL,a member of the collectin family in the C-type lectin superfamily, is an important serum component associated with innate immunity. Toll-like receptors (TLRs are expressed extensively, and have been shown to be involved in C. albicans-induced cellular responses. We first examined whether MBL modulated heat-killed (HK C. albicans-induced cellular responses in phorbol 12-myristate 13-acetate (PMA-activated human THP-1 macrophages. We then investigated the possible mechanisms of its inhibitory effect. METHODOLOGY/PRINCIPAL FINDING: Enzyme-linked immunosorbent assay (ELISA and reverse transcriptasepolymerase chain reaction (RT-PCR analysis showed that MBL at higher concentrations (10-20 µg/ml significantly attenuated C. albicans-induced chemokine (e.g., IL-8 and proinflammatory cytokine (e.g., TNF-α production from PMA-activated THP-1 cells at both protein and mRNA levels. Electrophoretic mobility shift assay (EMSA and Western blot (WB analysis showed that MBL could inhibit C. albicans-induced nuclear factor-κB (NF-κB DNA binding and its translocation in PMA-activated THP-1 cells. MBL could directly bind to PMA-activated THP-1 cells in the presence of Ca(2+, and this binding decreased TLR2 and TLR4 expressions in C. albicans-induced THP-1 macrophages. Furthermore, the binding could be partially inhibited by both anti-TLR2 monoclonal antibody (clone TL2.1 and anti-TLR4 monoclonal antibody (clone HTA125. In addition, co-immunoprecipitation experiments and microtiter wells assay showed that MBL could directly bind to the recombinant soluble form of extracellular TLR2 domain (sTLR2 and sTLR4. CONCLUSIONS/SIGNIFICANCE: Our study demonstrates that MBL can affect proinflammatory cytokine and chemokine expressions by modifying C. albicans-/TLR-signaling pathways. This study supports

  7. Protein Kinase C and Toll-Like Receptor Signaling

    Directory of Open Access Journals (Sweden)

    Daniel J. Loegering

    2011-01-01

    Full Text Available Protein kinase C (PKC is a family of kinases that are implicated in a plethora of diseases, including cancer and cardiovascular disease. PKC isoforms can have different, and sometimes opposing, effects in these disease states. Toll-like receptors (TLRs are a family of pattern recognition receptors that bind pathogens and stimulate the secretion of cytokines. It has long been known that PKC inhibitors reduce LPS-stimulated cytokine secretion by macrophages, linking PKC activation to TLR signaling. Recent studies have shown that PKC-α, -δ, -ε, and -ζ are directly involved in multiple steps in TLR pathways. They associate with the TLR or proximal components of the receptor complex. These isoforms are also involved in the downstream activation of MAPK, RhoA, TAK1, and NF-κB. Thus, PKC activation is intimately involved in TLR signaling and the innate immune response.

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

    Science.gov (United States)

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

    2016-05-26

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

  9. A temporal gate for viral enhancers to co-opt Toll-like-receptor transcriptional activation pathways upon acute infection.

    Science.gov (United States)

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

    2015-04-01

    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

  10. A temporal gate for viral enhancers to co-opt Toll-like-receptor transcriptional activation pathways upon acute infection.

    Directory of Open Access Journals (Sweden)

    Kai A Kropp

    2015-04-01

    Full Text Available 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

  11. Targeting Toll-Like Receptors for Treatment of SLE

    Directory of Open Access Journals (Sweden)

    Christopher G. Horton

    2010-01-01

    Full Text Available Toll-like receptors (TLRs are important innate immune receptors for the identification and clearance of invading pathogens. Twelve TLRs that recognize various conserved components of microorganisms are currently known. Among these, the endosomal TLRs 3, 7/8, and 9 recognize dsRNA, ssRNA, and CpG DNA, respectively. Nucleic acid-sensing TLRs, TLR 7 in particular, have been implicated in systemic lupus erythematosus (SLE and are thought to exacerbate disease pathology. Activation of these TLRs results in the production of inflammatory cytokines and type I interferon. Genome-wide association studies, single nucleotide polymorphism analyses as well as experimental mouse models have provided evidence of TLR signaling involvement in SLE and other autoimmune diseases. Since activation of these receptor pathways promotes autoimmune phenotypes, inhibitory drugs that target these pathways constitute important new therapeutic strategies for the treatment of systemic autoimmunity.

  12. Activation of μ-opioid receptor and Toll-like receptor 4 by plasma from morphine-treated mice.

    Science.gov (United States)

    Xie, Nan; Gomes, Fabio P; Deora, Vandana; Gregory, Kye; Vithanage, Tharindu; Nassar, Zeyad D; Cabot, Peter J; Sturgess, David; Shaw, Paul N; Parat, Marie-Odile

    2017-03-01

    In this study, we quantified the ability of opioids present in biological samples to activate the μ-opioid receptor and TLR4 using cell-based assays. Each assay was standardised, in the presence of plasma, using morphine, its μ receptor-active metabolite morphine-6 glucuronide (M6G) and its μ receptor-inactive, but TLR4-active metabolite morphine-3 glucuronide (M3G). Specificity was verified using antagonists. Morphine- and M6G-spiked plasma samples exhibited μ receptor activation, which M3G-spiked plasma lacked. In contrast, M3G showed moderate but consistent activation of TLR-4. Plasma samples were collected at a number of time points from mice administered morphine (1 or 10mg/kg every 12h for 3days) or saline. Morphine administration led to intermittent μ receptor activation, reversed by μ receptor antagonists, and to TRL4 activation at time points where M3G is measured in plasma. Interestingly, this protocol of morphine administration also led to TLR4-independent NF-κB activation, at time points where M3G was not detected, presumably via elevation of circulating cytokines including, but not limited to, TNFα. Circulating TNFα was increased after three days of morphine administration, and TNFα mRNA elevated in the spleen of morphine-treated mice.

  13. DMPD: Translational mini-review series on Toll-like receptors: networks regulated byToll-like receptors mediate innate and adaptive immunity. [Dynamic Macrophage Pathway CSML Database

    Lifescience Database Archive (English)

    Full Text Available 17223959 Translational mini-review series on Toll-like receptors: networks regulate...ol. 2007 Feb;147(2):199-207. (.png) (.svg) (.html) (.csml) Show Translational mini-review series on Toll-like receptors: network... immunity. PubmedID 17223959 Title Translational mini-review series on Toll-like receptors: networks regulat

  14. Combating Drug Abuse by Targeting Toll-Like Receptor 4 (TLR)

    Science.gov (United States)

    2015-12-01

    AWARD NUMBER: W81XWH-12-1-0345 PROJECT TITLE: Combating drug abuse by targeting toll-like receptor 4 (TLR) PRINCIPAL INVESTIGATOR: Dr. Linda...5a. CONTRACT NUMBER not applicable Combating drug abuse by targeting toll-like receptor 4 (TLR) 5b. GRANT NUMBER W81XWH-12-1-0345 5c. PROGRAM...naltrexone; drug abuse ; glial activation; therapeutic approach to treating drug abuse ; opioids; cocaine 16. SECURITY CLASSIFICATION OF: 17. LIMITATION

  15. Toll-like receptors as therapeutic targets in cystic fibrosis.

    LENUS (Irish Health Repository)

    Greene, Catherine M

    2008-12-01

    Background: Toll-like receptors (TLRs) are pattern recognition receptors that act as a first-line of defence in the innate immune response by recognising and responding to conserved molecular patterns in microbial factors and endogenous danger signals. Cystic fibrosis (CF)-affected airways represent a milieu potentially rich in TLR agonists and the chronic inflammatory phenotype evident in CF airway epithelial cells is probably due in large part to activation of TLRs. Objective\\/methods: To examine the prospects of developing novel therapies for CF by targeting TLRs. We outline the expression and function of TLRs and explore the therapeutic potential of naturally-occurring and synthetic TLR inhibitors for CF. Results\\/conclusion: Modulation of TLRs has therapeutic potential for the inflammatory lung manifestations of CF.

  16. Plasma membrane Toll-like receptor activation increases bacterial uptake but abrogates endosomal Lactobacillus acidophilus induction of interferon-β.

    Science.gov (United States)

    Boye, Louise; Welsby, Iain; Lund, Lisbeth Drozd; Goriely, Stanislas; Frøkiaer, Hanne

    2016-11-01

    Lactobacillus acidophilus induces a potent interferon-β (IFN-β) response in dendritic cells (DCs) by a Toll-like receptor 2 (TLR2) -dependent mechanism, in turn leading to strong interleukin-12 (IL-12) production. In the present study, we investigated the involvement of different types of endocytosis in the L. acidophilus-induced IFN-β and IL-12 responses and how TLR2 or TLR4 ligation by lipopolysaccharide and Pam3/4CSK4 influenced endocytosis of L. acidophilus and the induced IFN-β and IL-12 production. Lactobacillus acidophilus was endocytosed by constitutive macropinocytosis taking place in the immature cells as well as by spleen tyrosine kinase (Syk) -dependent phagocytosis but without involvement of plasma membrane TLR2. Stimulation with TLR2 or TLR4 ligands increased macropinocytosis in a Syk-independent manner. As a consequence, incubation of DCs with TLR ligands before incubation with L. acidophilus enhanced the uptake of the bacteria. However, in these experimental conditions, induction of IFN-β and IL-12 was strongly inhibited. As L. acidophilus-induced IFN-β depends on endocytosis and endosomal degradation before signalling and as TLR stimulation from the plasma membrane leading to increased macropinocytosis abrogates IFN-β induction we conclude that plasma membrane TLR stimulation leading to increased macropinocytosis decreases endosomal induction of IFN-β and speculate that this is due to competition between compartments for molecules involved in the signal pathways. In summary, endosomal signalling by L. acidophilus that leads to IFN-β and IL-12 production is inhibited by TLR stimulation from the plasma membrane.

  17. Toll-Like Receptors, Their Ligands, and Atherosclerosis

    Directory of Open Access Journals (Sweden)

    Conrad P. Hodgkinson

    2011-01-01

    Full Text Available Atherosclerosis is a disease characterized by inflammation in the arterial wall. Atherogenesis is dependent on the innate immune response involving activation of Toll-like receptors (TLRs and the expression of inflammatory proteins. TLRs, which recognize various pathogen-associated molecular patterns, are expressed in various cell types within the atherosclerotic plaque. Microbial agents are associated with an increased risk of atherosclerosis and this is, in part, due to activation of TLRs. Recently considerable evidence has been provided suggesting that endogenous proteins promote atherosclerosis by binding to TLRs. In this review, we describe the role of TLRs in atherosclerosis with particular emphasis on those atherogenic endogenous proteins that have been implicated as TLR ligands.

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

    DEFF Research Database (Denmark)

    Kornblit, Brian; Enevold, Christian; Wang, Tao;

    2014-01-01

    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 rs...

  19. Evidence for adaptation of porcine Toll-like receptors

    NARCIS (Netherlands)

    Darfour-Oduro, Kwame A.; Megens, Hendrik Jan; Roca, Alfred; Groenen, Martien A.M.; Schook, Lawrence B.

    2016-01-01

    Naturally endemic infectious diseases provide selective pressures for pig populations. Toll-like receptors (TLRs) represent the first line of immune defense against pathogens and are likely to play a crucial adaptive role for pig populations. This study was done to determine whether wild and dome

  20. Current Views of Toll-Like Receptor Signaling Pathways

    Directory of Open Access Journals (Sweden)

    Masahiro Yamamoto

    2010-01-01

    Full Text Available On microbial invasion, the host immediately evokes innate immune responses. Recent studies have demonstrated that Toll-like receptors (TLRs play crucial roles in innate responses that lead not only to the clearance of pathogens but also to the efficient establishment of acquired immunity by directly detecting molecules from microbes. In terms of intracellular TLR-mediated signaling pathways, cytoplasmic adaptor molecules containing Toll/IL-1R (TIR domains play important roles in inflammatory immune responses through the production of proinflammatory cytokines, nitric oxide, and type I interferon, and upregulation of costimulatory molecules. In this paper, we will describe our current understanding of the relationship between TLRs and their ligands derived from pathogens such as viruses, bacteria, fungi, and parasites. Moreover, we will review the historical and current literature to describe the mechanisms behind TLR-mediated activation of innate immune responses.

  1. Toll-Like Receptors in Leishmania Infections: Guardians or Promoters?

    Directory of Open Access Journals (Sweden)

    Marilia S. Faria

    2012-01-01

    Full Text Available Protozoa of the genus Leishmania cause a wide variety of pathologies ranging from self-healing skin lesions to visceral damage, depending on the parasite species. The outcome of infection depends on the quality of the adaptive immune response, which is determined by parasite factors and the host genetic background. Innate responses, resulting in the generation of mediators with anti-leishmanial activity, contribute to parasite control and help the development of efficient adaptive responses. Among those, the potential contribution of members of the Toll-like receptors (TLRs family in the control of Leishmania infections started to be investigated about a decade ago. Although most studies appoint a protective role for TLRs, there is growing evidence that in some cases, TLRs facilitate infection. This review highlights recent advances in TLR function during Leishmania infections and discusses their potential role in restraining parasite growth versus yielding disease.

  2. Toll-like receptor responses in IRAK-4-deficient neutrophils.

    Science.gov (United States)

    van Bruggen, Robin; Drewniak, Agata; Tool, Anton T J; Jansen, Machiel; van Houdt, Michel; Geissler, Judy; van den Berg, Timo K; Chapel, Helen; Kuijpers, Taco W

    2010-01-01

    Human neutrophils were found to express all known Toll-like receptors (TLRs) except TLR3 and TLR7. IRAK-4-deficient neutrophils were tested for their responsiveness to various TLR ligands. Essentially all TLR responses in neutrophils, including the induction of reactive oxygen species generation, adhesion, chemotaxis and IL-8 secretion, were found to be dependent on IRAK-4. Surprisingly, the reactivity towards certain established TLR ligands, imiquimod and ODN-CpG, was unaffected by IRAK-4 deficiency, demonstrating their activity is independent of TLR. TLR-4-dependent signaling in neutrophils was totally dependent on IRAK-4 without any major TRIF-mediated contribution. We did not observe any defects in killing capacity of IRAK-4-deficient neutrophils for Staphylococcus aureus, Escherichia coli and Candida albicans, suggesting that microbial killing is primarily TLR independent.

  3. THE IMPACT OF ANTIFUNGALS ON TOLL-LIKE RECEPTORS

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    Mircea Radu Mihu

    2014-03-01

    Full Text Available Fungi are increasingly recognized as major pathogens in immunocompromised individuals. The most common invasive fungal infections are caused by Candida spp., Aspergillus spp. and Cryptococcus spp. Amphotericin B has remained the cornerstone of therapy against many fulminant fungal infections but its use is limited by its multitude of side effects. Echinocandins are a newer class of antifungal drugs with activity against Candida spp. and Aspergillus spp. and constitutes an alternative to amphotericin B due to superior patient tolerability and fewer side effects. Due to their excellent bioavailability and oral availability, azoles continue to be heavily used for simple, such as fluconazole for candidal vaginitis, and complex diseases, such as voriconazole for aspergilloisis. The objective of this paper is to present current knowledge regarding the multiple interactions between the broad spectrum antifungals and the innate immune response, primarily focusing on the toll-like receptors.

  4. TGFβ activated kinase 1 (TAK1 at the crossroad of B cell receptor and Toll-like receptor 9 signaling pathways in human B cells.

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    Dániel Szili

    Full Text Available B cell development and activation are regulated by combined signals mediated by the B cell receptor (BCR, receptors for the B-cell activating factor of the tumor necrosis factor family (BAFF-R and the innate receptor, Toll-like receptor 9 (TLR9. However, the underlying mechanisms by which these signals cooperate in human B cells remain unclear. Our aim was to elucidate the key signaling molecules at the crossroads of BCR, BAFF-R and TLR9 mediated pathways and to follow the functional consequences of costimulation.Therefore we stimulated purified human B cells by combinations of anti-Ig, B-cell activating factor of the tumor necrosis factor family (BAFF and the TLR9 agonist, CpG oligodeoxynucleotide. Phosphorylation status of various signaling molecules, B cell proliferation, cytokine secretion, plasma blast generation and the frequency of IgG producing cells were investigated. We have found that BCR induced signals cooperate with BAFF-R- and TLR9-mediated signals at different levels of cell activation. BCR and BAFF- as well as TLR9 and BAFF-mediated signals cooperate at NFκB activation, while BCR and TLR9 synergistically costimulate mitogen activated protein kinases (MAPKs, ERK, JNK and p38. We show here for the first time that the MAP3K7 (TGF beta activated kinase, TAK1 is responsible for the synergistic costimulation of B cells by BCR and TLR9, resulting in an enhanced cell proliferation, plasma blast generation, cytokine and antibody production. Specific inhibitor of TAK1 as well as knocking down TAK1 by siRNA abrogates the synergistic signals. We conclude that TAK1 is a key regulator of receptor crosstalk between BCR and TLR9, thus plays a critical role in B cell development and activation.

  5. Rotavirus activates lymphocytes from non-obese diabetic mice by triggering toll-like receptor 7 signaling and interferon production in plasmacytoid dendritic cells.

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    Jessica A Pane

    2014-03-01

    Full Text Available It has been proposed that rotavirus infection promotes the progression of genetically-predisposed children to type 1 diabetes, a chronic autoimmune disease marked by infiltration of activated lymphocytes into pancreatic islets. Non-obese diabetic (NOD mice provide a model for the human disease. Infection of adult NOD mice with rhesus monkey rotavirus (RRV accelerates diabetes onset, without evidence of pancreatic infection. Rather, RRV spreads to the pancreatic and mesenteric lymph nodes where its association with antigen-presenting cells, including dendritic cells, induces cellular maturation. RRV infection increases levels of the class I major histocompatibility complex on B cells and proinflammatory cytokine expression by T cells at these sites. In autoimmunity-resistant mice and human mononuclear cells from blood, rotavirus-exposed plasmacytoid dendritic cells contribute to bystander polyclonal B cell activation through type I interferon expression. Here we tested the hypothesis that rotavirus induces bystander activation of lymphocytes from NOD mice by provoking dendritic cell activation and proinflammatory cytokine secretion. NOD mouse splenocytes were stimulated with rotavirus and assessed for activation by flow cytometry. This stimulation activated antigen-presenting cells and B cells independently of virus strain and replicative ability. Instead, activation depended on virus dose and was prevented by blockade of virus decapsidation, inhibition of endosomal acidification and interference with signaling through Toll-like receptor 7 and the type I interferon receptor. Plasmacytoid dendritic cells were more efficiently activated than conventional dendritic cells by RRV, and contributed to the activation of B and T cells, including islet-autoreactive CD8+ T cells. Thus, a double-stranded RNA virus can induce Toll-like receptor 7 signaling, resulting in lymphocyte activation. Our findings suggest that bystander activation mediated by type I

  6. Mechanisms for the activation of Toll-like receptor 2/4 by saturated fatty acids and inhibition by docosahexaenoic acid.

    Science.gov (United States)

    Hwang, Daniel H; Kim, Jeong-A; Lee, Joo Young

    2016-08-15

    Saturated fatty acids can activate Toll-like receptor 2 (TLR2) and TLR4 but polyunsaturated fatty acids, particularly docosahexaenoic acid (DHA) inhibit the activation. Lipopolysaccharides (LPS) and lipopetides, ligands for TLR4 and TLR2, respectively, are acylated by saturated fatty acids. Removal of these fatty acids results in loss of their ligand activity suggesting that the saturated fatty acyl moieties are required for the receptor activation. X-ray crystallographic studies revealed that these saturated fatty acyl groups of the ligands directly occupy hydrophobic lipid binding domains of the receptors (or co-receptor) and induce the dimerization which is prerequisite for the receptor activation. Saturated fatty acids also induce the dimerization and translocation of TLR4 and TLR2 into lipid rafts in plasma membrane and this process is inhibited by DHA. Whether saturated fatty acids induce the dimerization of the receptors by interacting with these lipid binding domains is not known. Many experimental results suggest that saturated fatty acids promote the formation of lipid rafts and recruitment of TLRs into lipid rafts leading to ligand independent dimerization of the receptors. Such a mode of ligand independent receptor activation defies the conventional concept of ligand induced receptor activation; however, this may enable diverse non-microbial molecules with endogenous and dietary origins to modulate TLR-mediated immune responses. Emerging experimental evidence reveals that TLRs play a key role in bridging diet-induced endocrine and metabolic changes to immune responses.

  7. Macrophages exposed continuously to lipopolysaccharide and other agonists that act via toll-like receptors exhibit a sustained and additive activation state

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    Ozinsky Adrian O

    2001-10-01

    Full Text Available Abstract Background Macrophages sense microorganisms through activation of members of the Toll-like receptor family, which initiate signals linked to transcription of many inflammation associated genes. In this paper we examine whether the signal from Toll-like receptors [TLRs] is sustained for as long as the ligand is present, and whether responses to different TLR agonists are additive. Results RAW264 macrophage cells were doubly-transfected with reporter genes in which the IL-12p40, ELAM or IL-6 promoter controls firefly luciferase, and the human IL-1β promoter drives renilla luciferase. The resultant stable lines provide robust assays of macrophage activation by TLR stimuli including LPS [TLR4], lipopeptide [TLR2], and bacterial DNA [TLR9], with each promoter demonstrating its own intrinsic characteristics. With each of the promoters, luciferase activity was induced over an 8 hr period, and thereafter reached a new steady state. Elevated expression required the continued presence of agonist. Sustained responses to different classes of agonist were perfectly additive. This pattern was confirmed by measuring inducible cytokine production in the same cells. While homodimerization of TLR4 mediates responses to LPS, TLR2 appears to require heterodimerization with another receptor such as TLR6. Transient expression of constitutively active forms of TLR4 or TLR2 plus TLR6 stimulated IL-12 promoter activity. The effect of LPS, a TLR4 agonist, was additive with that of TLR2/6 but not TLR4, whilst that of lipopeptide, a TLR2 agonist, was additive with TLR4 but not TLR2/6. Actions of bacterial DNA were additive with either TLR4 or TLR2/6. Conclusions These findings indicate that maximal activation by any one TLR pathway does not preclude further activation by another, suggesting that common downstream regulatory components are not limiting. Upon exposure to a TLR agonist, macrophages enter a state of sustained activation in which they continuously

  8. Mechanisms of disease: Toll-like receptors in cardiovascular disease.

    Science.gov (United States)

    Frantz, Stefan; Ertl, Georg; Bauersachs, Johann

    2007-08-01

    The innate immune system detects highly conserved, relatively invariant structural motifs of pathogens. Toll-like receptors (TLRs) have been identified as the primary innate immune receptors. TLRs distinguish between different patterns of pathogens and activate a rapid innate immune response; however, TLRs can also be activated by host-derived molecules. In addition to being expressed in immune cells, TLRs are expressed in other tissues, such as those of the cardiovascular system. TLRs could, therefore, be a key link between cardiovascular disease development and the immune system. Indeed, evidence that TLR activation contributes to the development and progression of atherosclerosis, cardiac dysfunction in sepsis, and congestive heart failure, is convincing. Although much has been learned about TLR activation in cellular components of the cardiovascular system, the role individual TLR family members have in the pathophysiology of cardiovascular diseases and hence in clinical practice remains to be defined. Here we review the rapid progress that has been made in this field, which has improved our understanding of vascular as well as myocardial TLR function in basic and clinical science.

  9. Direct and Indirect Role of Toll-Like Receptors in T Cell Mediated Immunity

    Institute of Scientific and Technical Information of China (English)

    DamoXu; HaiyingLiu; MousaKomai-Koma

    2004-01-01

    Toll-like receptors (TLR) are pathogen-associated molecular patterns (PAMPs) recognition receptors that play an important role in protective immunity against infection and inflammation. They act as central integrators of a wide variety of signals, responding to diverse agonists of microbial products. Stimulation of Toll-like receptors by microbial products leads to signaling pathways that activate not only innate, but also adaptive immunity by APC dependent or independent mechanisms. Recent evidence revealed that TLR signals played a determining role in the skewing of naive T cells towards either Thl or Th2 responses. Activation of Toll-like receptors also directly or indirectly influences regulatory T cell functions. Therefore, TLRs are required in both immune activation and immune regulation. Study of TLRs has significantly enhanced our understanding of innate and adaptive immune responses and provides novel therapeutic approaches against infectious and inflammatory diseases. Cellular & Molecular Immunology.

  10. Direct and Indirect Role of Toll-Like Receptors in T Cell Mediated Immunity

    Institute of Scientific and Technical Information of China (English)

    Damo Xu; Haiying Liu; Mousa Komai-Koma

    2004-01-01

    Toll-like receptors (TLR) are pathogen-associated molecular patterns (PAMPs) recognition receptors that play an important role in protective immunity against infection and inflammation. They act as central integrators of a wide variety of signals, responding to diverse agonists of microbial products. Stimulation of Toll-like receptors by microbial products leads to signaling pathways that activate not only innate, but also adaptive immunity by APC dependent or independent mechanisms. Recent evidence revealed that TLR signals played a determining role in the skewing of na(i)ve T cells towards either Th1 or Th2 responses. Activation of Toll-like receptors also directly or indirectly influences regulatory T cell functions. Therefore, TLRs are required in both immune activation and immune regulation. Study of TLRs has significantly enhanced our understanding of innate and adaptive immune responses and provides novel therapeutic approaches against infectious and inflammatory diseases.

  11. Toll-like receptor 2 agonists inhibit human fibrocyte differentiation

    OpenAIRE

    Maharjan Anu S; Pilling Darrell; Gomer Richard H

    2010-01-01

    Abstract Background In healing wounds, some monocytes enter the wound and differentiate into fibroblast-like cells called fibrocytes. Since Toll-like receptors (TLRs) are present on monocytes, and pathogens that can infect a wound have and/or release TLR agonists, we examined whether TLR agonists affect fibrocyte differentiation. Results When human peripheral blood mononuclear cells (PBMCs) were cultured with TLR3, TLR4, TLR5, TLR7, TLR8 or TLR9 agonists, there was no significant effect on fi...

  12. Crosstalk between Complement and Toll-like Receptor Activation in Relation to Donor Brain Death and Renal Ischemia-Reperfusion Injury

    NARCIS (Netherlands)

    Damman, Jeffrey; Daha, Mohamed R.; van Son, Willem J.; Leuvenink, Henri G.; Ploeg, Rutger J.; Seelen, Marc A.

    2011-01-01

    Two central pathways of innate immunity, complement and Toll-like receptors (TLRs), play an important role in the pathogenesis of renal injury inherent to kidney transplantation. Recent findings indicate close crosstalk between complement and TLR signaling pathways. It is suggested that mitogen acti

  13. DMPD: Toll-like receptors regulation of viral infection and disease. [Dynamic Macrophage Pathway CSML Database

    Lifescience Database Archive (English)

    Full Text Available 18280610 Toll-like receptors regulation of viral infection and disease. Thompson JM...how Toll-like receptors regulation of viral infection and disease. PubmedID 18280610 Title Toll-like recepto...rs regulation of viral infection and disease. Authors Thompson JM, Iwasaki A. Pub

  14. DMPD: Toll like receptors and autoimmunity: a critical appraisal. [Dynamic Macrophage Pathway CSML Database

    Lifescience Database Archive (English)

    Full Text Available 17959357 Toll like receptors and autoimmunity: a critical appraisal. Papadimitraki ...ml) Show Toll like receptors and autoimmunity: a critical appraisal. PubmedID 17959357 Title Toll like recep...tors and autoimmunity: a critical appraisal. Authors Papadimitraki ED, Bertsias G

  15. DMPD: Endogenous ligands of Toll-like receptors. [Dynamic Macrophage Pathway CSML Database

    Lifescience Database Archive (English)

    Full Text Available 15178705 Endogenous ligands of Toll-like receptors. Tsan MF, Gao B. J Leukoc Biol. ...2004 Sep;76(3):514-9. Epub 2004 Jun 3. (.png) (.svg) (.html) (.csml) Show Endogenous ligands of Toll-like re...ceptors. PubmedID 15178705 Title Endogenous ligands of Toll-like receptors. Authors Tsan MF, Gao B. Publicat

  16. DMPD: Toll-like receptors in atherosclerosis. [Dynamic Macrophage Pathway CSML Database

    Lifescience Database Archive (English)

    Full Text Available 18031244 Toll-like receptors in atherosclerosis. Tobias PS, Curtiss LK. Biochem Soc... Trans. 2007 Dec;35(Pt 6):1453-5. (.png) (.svg) (.html) (.csml) Show Toll-like receptors in atherosclerosis.... PubmedID 18031244 Title Toll-like receptors in atherosclerosis. Authors Tobias PS, Curtiss LK. Publication

  17. Fatty acids modulate Toll-like receptor 4 activation through regulation of receptor dimerization and recruitment into lipid rafts in a reactive oxygen species-dependent manner.

    Science.gov (United States)

    Wong, Scott W; Kwon, Myung-Ja; Choi, Augustine M K; Kim, Hong-Pyo; Nakahira, Kiichi; Hwang, Daniel H

    2009-10-02

    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 demonstrated that saturated and polyunsaturated fatty acids reciprocally modulate the activation of TLR4. However, the underlying mechanism has not been understood. Here, we report for the first time that the saturated fatty acid lauric acid induced dimerization and recruitment of TLR4 into lipid rafts, however, dimerization was not observed in non-lipid raft fractions. Similarly, LPS and lauric acid enhanced the association of TLR4 with MD-2 and downstream adaptor molecules, TRIF and MyD88, into lipid rafts leading to the activation of downstream signaling pathways and target gene expression. However, docosahexaenoic acid (DHA), an n-3 polyunsaturated fatty acid, inhibited LPS- or lauric acid-induced dimerization and recruitment of TLR4 into lipid raft fractions. Together, these results demonstrate that lauric acid and DHA reciprocally modulate TLR4 activation by regulation of the dimerization and recruitment of TLR4 into lipid rafts. In addition, we showed that TLR4 recruitment to lipid rafts and dimerization were coupled events mediated at least in part by NADPH oxidase-dependent reactive oxygen species generation. These results provide a new insight in understanding the mechanism by which fatty acids differentially modulate TLR4-mediated signaling pathway and consequent inflammatory responses which are implicated in the development and progression of many chronic diseases.

  18. Indirect Toll-like receptor 5-mediated activation of conventional dendritic cells promotes the mucosal adjuvant activity of flagellin in the respiratory tract.

    Science.gov (United States)

    Fougeron, Delphine; Van Maele, Laurye; Songhet, Pascal; Cayet, Delphine; Hot, David; Van Rooijen, Nico; Mollenkopf, Hans-Joachim; Hardt, Wolf-Dietrich; Benecke, Arndt G; Sirard, Jean-Claude

    2015-06-26

    The Toll-like receptor 5 (TLR5) agonist flagellin is an effective adjuvant for vaccination. Recently, we demonstrated that the adaptive responses stimulated by intranasal administration of flagellin and antigen were linked to TLR5 signaling in the lung epithelium. The present study sought to identify the antigen presenting cells involved in this adjuvant activity. We first found that the lung dendritic cells captured antigen very efficiently in a process independent of TLR5. However, TLR5-mediated signaling specifically enhanced the maturation of lung dendritic cells. Afterward, the number of antigen-bound and activated conventional dendritic cells (both CD11b(+) and CD103(+)) increased in the mediastinal lymph nodes in contrast to monocyte-derived dendritic cells. These data suggested that flagellin-activated lung conventional dendritic cells migrate to the draining lymph nodes. The lymph node dendritic cells, in particular CD11b(+) cells, were essential for induction of CD4 T-cell response. Lastly, neutrophils and monocytes were recruited into the lungs by flagellin administration but did not contribute to the adjuvant activity. The functional activation of conventional dendritic cells was independent of direct TLR5 signaling, thereby supporting the contribution of maturation signals produced by flagellin-stimulated airway epithelium. In conclusion, our results demonstrated that indirect TLR5-dependent stimulation of airway conventional dendritic cells is essential to flagellin's mucosal adjuvant activity.

  19. Role of Toll-like receptors in diabetic nephropathy.

    Science.gov (United States)

    Mudaliar, Harshini; Pollock, Carol; Panchapakesan, Usha

    2014-05-01

    Diabetic nephropathy is the leading cause of kidney failure and its increasing prevalence and incidence has imposed global socio-economic stress on healthcare systems worldwide. Although historically considered a metabolic disorder, recent studies have established that inflammatory responses are central to the pathogenesis of diabetic nephropathy. TLRs (Toll-like receptors) are a family of pattern recognition receptors responsible for the initiation of inflammatory and immune responses. The regulation of TLR2 and TLR4 have been implicated in the pathogenesis of various kidney diseases, and emerging evidence shows their involvement in the perpetuation of inflammation in the diabetic kidney. The present review focuses on the relative contributions of TLR2 and TLR4 in recognizing endogenous ligands relevant to diabetic nephropathy and their subsequent activation of NF-κB (nuclear factor κB), which results in the synthesis and secretion of pro-inflammatory cytokines and chemokines. Moreover, we discuss the pro-inflammatory signalling pathways of TLR2 and TLR4, in which their interruption or blockade may prove to be important therapeutic targets, potentially translated into clinical treatments for diabetic nephropathy. Currently, inhibitors to TLR2 and TLR4 are undergoing clinical trials in various inflammatory models of disease, but none in patients with diabetic nephropathy. Given the existing literature, there is a fundamental necessity to undertake trials in patients with diabetic nephropathy with a focus on renal end points.

  20. Toll-like receptors in invertebrate innate immunity

    Directory of Open Access Journals (Sweden)

    L Zheng

    2005-08-01

    Full Text Available Among invertebrates, innate immunity is the only defense mechanism against harmful non-self agents.In response to recognition of microbial pattern molecules, Drosophila melanogaster activates either theToll or Imd pathway, leading to the translocation of NF-kB (or Rel transcription factors from the cytoplasmto the nucleus and the subsequent production of antimicrobial peptides, which provide systemic innateimmunity. Toll-like receptors (TLRs are characterized by an extracellular leucine rich repeat (LRRdomain and an intracellular Toll/interleukin-1 receptor (TIR domain. TLRs are found from cnidarians tomammals. Here we argue that TLR mediated innate immunity developed during an early stage ofevolution when organisms acquired a body cavity. This is supported by the distributions of TLR and Relgenes in the animal kingdom. Further, TLR mediated immunity appears to have developed independentlyin invertebrates and vertebrates. Recent studies have shown that microbial molecules, with the potentialto signal through TLR, can be beneficial to host survival. Studies on this signaling pathway could opendoors to a better understanding of the origins of innate immunity in invertebrates and potentialtransmission blocking strategies aimed at ameliorating vector-borne diseases.

  1. The Toll-like receptor pathway establishes commensal gut colonization

    Science.gov (United States)

    Round, June L.; Lee, S. Melanie; Li, Jennifer; Tran, Gloria; Jabri, Bana; Chatila, Talal A.; Mazmanian, Sarkis K.

    2011-01-01

    Mucosal surfaces are in continuous contact with microbes. Toll-like receptors (TLRs) mediate recognition of microbial molecules to eliminate pathogens. In contrast, we demonstrate here that the prominent gut commensal, Bacteroides fragilis, activates the TLR pathway on T lymphocytes to establish host-microbial symbiosis. TLR2 deletion on CD4+ T cells results in anti-microbial immune responses that reduce B. fragilis colonization of a unique mucosal niche during homeostasis. A symbiosis factor (PSA) of B. fragilis activates TLR2 directly on Foxp3+ regulatory T cells through a novel process to engender mucosal tolerance. Remarkably, B. fragilis lacking PSA is unable to restrain host immune responses and is defective in niche-specific mucosal colonization. Therefore, unlike pathogens whose TLR ligands trigger inflammation, some commensal bacteria exploit the TLR pathway to actively suppress immune reactions. We propose that the immunologic distinction between pathogens and the microbiota is mediated not solely by host mechanisms, but also through specialized molecules evolved by symbiotic bacteria that enable commensal colonization. PMID:21512004

  2. Toll-Like Receptor 9 Agonists for Cancer Therapy

    Directory of Open Access Journals (Sweden)

    Davide Melisi

    2014-08-01

    Full Text Available The immune system has acquired increasing importance as a key player in cancer maintenance and growth. Thus, modulating anti-tumor immune mediators has become an attractive strategy for cancer treatment. Toll-like receptors (TLRs have gradually emerged as potential targets of newer immunotherapies. TLR-9 is preferentially expressed on endosome membranes of B-cells and plasmacytoid dendritic cells (pDC and is known for its ability to stimulate specific immune reactions through the activation of inflammation-like innate responses. Several synthetic CpG oligonucleotides (ODNs have been developed as TLR-9 agonists with the aim of enhancing cancer immune surveillance. In many preclinical models, CpG ODNs were found to suppress tumor growth and proliferation both in monotherapy and in addition to chemotherapies or target therapies. TLR-9 agonists have been also tested in several clinical trials in patients with solid tumors. These agents showed good tolerability and usually met activity endpoints in early phase trials. However, they have not yet been demonstrated to significantly impact survival, neither as single agent treatments, nor in combination with chemotherapies or cancer vaccines. Further investigations in larger prospective studies are required.

  3. Synergic activation of toll-like receptor (TLR 2/6 and 9 in response to Ureaplasma parvum & urealyticum in human amniotic epithelial cells.

    Directory of Open Access Journals (Sweden)

    Martha Triantafilou

    Full Text Available Ureaplasma species are the most frequently isolated microorganisms inside the amniotic cavity and have been associated with spontaneous abortion, chorioamnionitis, premature rupture of the membranes (PROM, preterm labour (PL pneumonia in neonates and bronchopulmonary dysplasia in neonates. The mechanisms by which Ureaplasmas cause such diseases remain unclear, but it is believed that inappropriate induction of inflammatory responses is involved, triggered by the innate immune system. As part of its mechanism of activation, the innate immune system employs germ-lined encoded receptors, called pattern recognition receptors (PRRs in order to "sense" pathogens. One such family of PRRs are the Toll like receptor family (TLR. In the current study we aimed to elucidate the role of TLRs in Ureaplasma-induced inflammation in human amniotic epithelial cells. Using silencing, as well as human embryonic kidney (HEK transfected cell lines, we demonstrate that TLR2, TLR6 and TLR9 are involved in the inflammatory responses against Ureaplasma parvum and urealyticum serovars. Ureaplasma lipoproteins, such as Multiple Banded antigen (MBA, trigger responses via TLR2/TLR6, whereas the whole bacterium is required for TLR9 activation. No major differences were observed between the different serovars. Cell activation by Ureaplasma parvum and urealyticum seem to require lipid raft function and formation of heterotypic receptor complexes comprising of TLR2 and TLR6 on the cell surface and TLR9 intracellularly.

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

    Science.gov (United States)

    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.

  5. The Architecture of the TIR Domain Signalosome in the Toll-like Receptor-4 Signaling Pathway

    OpenAIRE

    Emine Guven-Maiorov; Ozlem Keskin; Attila Gursoy; Carter VanWaes; Zhong Chen; Chung-Jung Tsai; Ruth Nussinov

    2015-01-01

    Scientific Reports | 5:13128 | DOI: 10.1038/srep13128 1 www.nature.com/scientificreports The Architecture of the TIR Domain Signalosome in the Toll-like Receptor-4 Signaling Pathway Emine Guven-Maiorov1,2, Ozlem Keskin1,2, Attila Gursoy2,3, Carter VanWaes4, Zhong Chen4, Chung-Jung Tsai5 & Ruth Nussinov5,6 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 understandin...

  6. Signaling flux redistribution at toll-like receptor pathway junctions.

    Directory of Open Access Journals (Sweden)

    Kumar Selvarajoo

    Full Text Available Various receptors on cell surface recognize specific extracellular molecules and trigger signal transduction altering gene expression in the nucleus. Gain or loss-of-function mutations of one molecule have shown to affect alternative signaling pathways with a poorly understood mechanism. In Toll-like receptor (TLR 4 signaling, which branches into MyD88- and TRAM-dependent pathways upon lipopolysaccharide (LPS stimulation, we investigated the gain or loss-of-function mutations of MyD88. We predict, using a computational model built on the perturbation-response approach and the law of mass conservation, that removal and addition of MyD88 in TLR4 activation, enhances and impairs, respectively, the alternative TRAM-dependent pathway through signaling flux redistribution (SFR at pathway branches. To verify SFR, we treated MyD88-deficient macrophages with LPS and observed enhancement of TRAM-dependent pathway based on increased IRF3 phosphorylation and induction of Cxcl10 and Ifit2. Furthermore, increasing the amount of MyD88 in cultured cells showed decreased TRAM binding to TLR4. Investigating another TLR4 pathway junction, from TRIF to TRAF6, RIP1 and TBK1, the removal of MyD88-dependent TRAF6 increased expression of TRAM-dependent Cxcl10 and Ifit2. Thus, we demonstrate that SFR is a novel mechanism for enhanced activation of alternative pathways when molecules at pathway junctions are removed. Our data suggest that SFR may enlighten hitherto unexplainable intracellular signaling alterations in genetic diseases where gain or loss-of-function mutations are observed.

  7. Polymorphisms of the Toll-like receptors and human disease.

    Science.gov (United States)

    Schwartz, David A; Cook, Donald N

    2005-11-15

    The Toll-like receptor (TLR) family regulates both innate and adaptive immune responses. Given its broad effect on immunity, the function of TLRs in various human diseases has been investigated largely by comparing the incidence of disease among persons with different polymorphisms in the genes that participate in TLR signaling. These studies demonstrate that TLR function affects several diseases, including sepsis, immunodeficiencies, atherosclerosis, and asthma. These findings have resulted in new opportunities to study the pathogenesis of disease, identify subpopulations at greater risk of disease, and, potentially, identify novel therapeutic approaches.

  8. Differential effects of the Toll-like receptor 2 agonists, PGN and Pam3CSK4 on anti-IgE induced human mast cell activation.

    Directory of Open Access Journals (Sweden)

    Yangyang Yu

    Full Text Available Mast cells are pivotal in the pathogenesis of allergy and inflammation. In addition to the classical IgE-dependent mechanism involving crosslinking of the high-affinity receptor for IgE (FcεRI, mast cells are also activated by Toll-like receptors (TLRs which are at the center of innate immunity. In this study, we demonstrated that the response of LAD2 cells (a human mast cell line to anti-IgE was altered in the presence of the TLR2 agonists peptidoglycan (PGN and tripalmitoyl-S-glycero-Cys-(Lys4 (Pam3CSK4. Pretreatment of PGN and Pam3CSK4 inhibited anti-IgE induced calcium mobilization and degranulation without down-regulation of FcεRI expression. Pam3CSK4 but not PGN acted in synergy with anti-IgE for IL-8 release when the TLR2 agonist was added simultaneously with anti-IgE. Studies with inhibitors of key enzymes implicated in mast cell signaling revealed that the synergistic release of IL-8 induced by Pam3CSK4 and anti-IgE involved ERK and calcineurin signaling cascades. The differential modulations of anti-IgE induced mast cell activation by PGN and Pam3CSK4 suggest that dimerization of TLR2 with TLR1 or TLR6 produced different modulating actions on FcεRI mediated human mast cell activation.

  9. MyD88-dependent and independent pathways of Toll-Like Receptors are engaged in biological activity of Triptolide in ligand-stimulated macrophages

    Directory of Open Access Journals (Sweden)

    Dorn Ruth

    2010-04-01

    Full Text Available Abstract Background Triptolide is a diterpene triepoxide from the Chinese medicinal plant Tripterygium wilfordii Hook F., with known anti-inflammatory, immunosuppressive and anti-cancer properties. Results Here we report the expression profile of immune signaling genes modulated by triptolide in LPS induced mouse macrophages. In an array study triptolide treatment modulated expression of 22.5% of one hundred and ninety five immune signaling genes that included Toll-like receptors (TLRs. TLRs elicit immune responses through their coupling with intracellular adaptor molecules, MyD88 and TRIF. Although it is known that triptolide inhibits NFκB activation and other signaling pathways downstream of TLRs, involvement of TLR cascade in triptolide activity was not reported. In this study, we show that triptolide suppresses expression of proinflammatory downstream effectors induced specifically by different TLR agonists. Also, the suppressive effect of triptolide on TLR-induced NFκB activation was observed when either MyD88 or TRIF was knocked out, confirming that both MyD88 and TRIF mediated NFκB activation may be inhibited by triptolide. Within the TLR cascade triptolide downregulates TLR4 and TRIF proteins. Conclusions This study reveals involvement of TLR signaling in triptolide activity and further increases understanding of how triptolide activity may downregulate NFκB activation during inflammatory conditions.

  10. DMPD: Signal transduction by the lipopolysaccharide receptor, Toll-like receptor-4. [Dynamic Macrophage Pathway CSML Database

    Lifescience Database Archive (English)

    Full Text Available 15379975 Signal transduction by the lipopolysaccharide receptor, Toll-like receptor... Signal transduction by the lipopolysaccharide receptor, Toll-like receptor-4. PubmedID 15379975 Title Signal transduction by the lip

  11. Epstein-Barr virus (EBV)-encoded small RNA is released from EBV-infected cells and activates signaling from Toll-like receptor 3.

    Science.gov (United States)

    Iwakiri, Dai; Zhou, Li; Samanta, Mrinal; Matsumoto, Misako; Ebihara, Takashi; Seya, Tsukasa; Imai, Shosuke; Fujieda, Mikiya; Kawa, Keisei; Takada, Kenzo

    2009-09-28

    Epstein-Barr virus-encoded small RNA (EBER) is nonpolyadenylated, noncoding RNA that forms stem-loop structure by intermolecular base-pairing, giving rise to double-stranded RNA (dsRNA)-like molecules, and exists abundantly in EBV-infected cells. Here, we report that EBER induces signaling from the Toll-like receptor 3 (TLR3), which is a sensor of viral double-stranded RNA (dsRNA) and induces type I IFN and proinflammatory cytokines. A substantial amount of EBER, which was sufficient to induce signaling from TLR3, was released from EBV-infected cells, and the majority of the released EBER existed as a complex with a cellular EBER-binding protein La, suggesting that EBER was released from the cells by active secretion of La. Sera from patients with infectious mononucleosis (IM), chronic active EBV infection (CAEBV), and EBV-associated hemophagocytic lymphohistiocytosis (EBV-HLH), whose general symptoms are caused by proinflammatory cytokines contained EBER, and addition of RNA purified from the sera into culture medium induced signaling from TLR3 in EBV-transformed lymphocytes and peripheral mononuclear cells. Furthermore, DCs treated with EBER showed mature phenotype and antigen presentation capacity. These findings suggest that EBER, which is released from EBV-infected cells, is responsible for immune activation by EBV, inducing type I IFN and proinflammatory cytokines. EBER-induced activation of innate immunity would account for immunopathologic diseases caused by active EBV infection.

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

    Science.gov (United States)

    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

  13. Toll-like receptors as targets for inflammation, development and repair in the central nervous system

    NARCIS (Netherlands)

    Noort, J.M. van

    2007-01-01

    Toll-like receptors (TLRs) that play key roles in inflammation are also widely expressed in the CNS. While they are well known to activate inflammatory responses to microbial products, TLRs fulfill additional roles in the absence of infection. Emerging evidence suggests that several TLRs play a role

  14. The Role of Toll-Like Receptor 2 in Inflammation and Fibrosis during Progressive Renal Injury

    NARCIS (Netherlands)

    Leemans, J.C.; Butter, L.M.; Pulskens, W.P.C.; Teske, G.J.D.; Claessen, N.; van der Poll, T.; Florquin, S.

    2009-01-01

    Tissue fibrosis and chronic inflammation are common causes of progressive organ damage, including progressive renal disease, leading to loss of physiological functions. Recently, it was shown that Toll-like receptor 2 (TLR2) is expressed in the kidney and activated by endogenous danger signals. The

  15. Crosstalk between complement and Toll-like receptor activation in relation to donor brain death and renal ischemia-reperfusion injury.

    Science.gov (United States)

    Damman, Jeffrey; Daha, Mohamed R; van Son, Willem J; Leuvenink, Henri G; Ploeg, Rutger J; Seelen, Marc A

    2011-04-01

    Two central pathways of innate immunity, complement and Toll-like receptors (TLRs), play an important role in the pathogenesis of renal injury inherent to kidney transplantation. Recent findings indicate close crosstalk between complement and TLR signaling pathways. It is suggested that mitogen activated protein kinases (MAPKs) might be the key molecules linking both the complement and TLR pathways together. Complement and TLRs are important mediators of renal ischemia-reperfusion injury (IRI). Besides IRI, complement C3 can also be upregulated and activated in the kidney before transplantation as a direct result of brain death (BD) in the donor. This local upregulation and activation of complement in the donor kidney has been proven to be detrimental for renal allograft outcome. Also TLR4 and several of its major ligands are upregulated by donor BD compared to living donors. Important and in line with the observations above, kidney transplant recipients have a benefit when receiving a kidney from a TLR4 Asp299Gly/Thr399Ile genotypic donor. The role of complement and TLRs and crosstalk between these two innate immune systems in relation to renal injury during donor BD and ischemia-reperfusion are focus of this review. Future strategies to target complement and TLR activation in kidney transplantation are considered.

  16. Toll-like receptor agonist augments virus-like particle-mediated protection from Ebola virus with transient immune activation.

    Directory of Open Access Journals (Sweden)

    Karen A O Martins

    Full Text Available Identifying safe and effective adjuvants is critical for the advanced development of protein-based vaccines. Pattern recognition receptor (PRR agonists are increasingly being explored as potential adjuvants, but there is concern that the efficacy of these molecules may be dependent on potentially dangerous levels of non-specific immune activation. The filovirus virus-like particle (VLP vaccine protects mice, guinea pigs, and nonhuman primates from viral challenge. In this study, we explored the impact of a stabilized dsRNA mimic, polyICLC, on VLP vaccination of C57BL/6 mice and Hartley guinea pigs. We show that at dose levels as low as 100 ng, the adjuvant increased the efficacy of the vaccine in mice. Antigen-specific, polyfunctional CD4 and CD8 T cell responses and antibody responses increased significantly upon inclusion of adjuvant. To determine whether the efficacy of polyICLC correlated with systemic immune activation, we examined serum cytokine levels and cellular activation in the draining lymph node. PolyICLC administration was associated with increases in TNFα, IL6, MCP1, MIP1α, KC, and MIP1β levels in the periphery and with the activation of dendritic cells (DCs, NK cells, and B cells. However, this activation resolved within 24 to 72 hours at efficacious adjuvant dose levels. These studies are the first to examine the polyICLC-induced enhancement of antigen-specific immune responses in the context of non-specific immune activation, and they provide a framework from which to consider adjuvant dose levels.

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

    Science.gov (United States)

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

    2013-07-01

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

  18. Local activation of uterine Toll-like receptor 2 and 2/6 decreases embryo implantation and affects uterine receptivity in mice.

    Science.gov (United States)

    Sanchez-Lopez, Javier Arturo; Caballero, Ignacio; Montazeri, Mehrnaz; Maslehat, Nasim; Elliott, Sarah; Fernandez-Gonzalez, Raul; Calle, Alexandra; Gutierrez-Adan, Alfonso; Fazeli, Alireza

    2014-04-01

    Embryo implantation is a complex interaction between maternal endometrium and embryonic structures. Failure to implant is highly recurrent and impossible to diagnose. Inflammation and infections in the female reproductive tract are common causes of infertility, embryo loss, and preterm labor. The current work describes how the activation of endometrial Toll-like receptor (TLR) 2 and 2/6 reduces embryo implantation chances. We developed a morphometric index to evaluate the effects of the TLR 2/6 activation along the uterine horn (UH). TLR 2/6 ligation reduced the endometrial myometrial and glandular indexes and increased the luminal index. Furthermore, TLR 2/6 activation increased the proinflammatory cytokines such as interleukin (IL)-1beta and monocyte chemotactic protein (MCP)-1 in UH lavages in the preimplantation day and IL-1 receptor antagonist in the implantation day. The engagement of TLR 2/6 with its ligand in the UH during embryo transfer severely affected the rate of embryonic implantation (45.00% ± 6.49% vs. 16.69% ± 5.01%, P embryo implantation process was verified using an in vitro model of human embryo implantation where trophoblast spheroids failed to adhere to a monolayer of TLR 2- and TLR 2/6-activated endometrial cells. The inhibition of TLR receptors 2 and 6 in the presence of their specific ligands restored the ability of the spheroids to bind to the endometrial cells. In conclusion, the activation of the innate immune system in the uterus at the time of implantation interfered with the endometrial receptivity and reduced the chances of implantation success.

  19. Inhibition of phosphoinositide 3-kinase enhances TRIF-dependent NF-kappa B activation and IFN-beta synthesis downstream of Toll-like receptor 3 and 4.

    Science.gov (United States)

    Aksoy, Ezra; Vanden Berghe, Wim; Detienne, Sophie; Amraoui, Zoulikha; Fitzgerald, Kathrine A; Haegeman, Guy; Goldman, Michel; Willems, Fabienne

    2005-07-01

    Phosphoinositide 3-kinases (PI3K) are known to regulate Toll-like receptor (TLR)-mediated inflammatory responses, but their impact on the different pathways of TLR signaling remains to be clarified. Here, we investigated the consequences of pharmacological inhibition of PI3K on Toll-IL-1 receptor domain-containing adapter-inducing IFN-beta (TRIF)-dependent signaling, which induces IFN-beta gene expression downstream of TLR3 and TLR4. First, treatment of monocyte-derived dendritic cells (DC) with wortmannin or LY294002 was found to enhance IFN-beta expression upon TLR3 or TLR4 engagement. In the same models of DC activation, PI3K inhibition increased DNA-binding activity of NF-kappaB, but not interferon response factor (IRF)-3, the key transcription factors required for TLR-mediated IFN-beta synthesis. In parallel, wortmannin-treated DC exhibited enhanced levels of IkappaB kinase (IKK)-alpha/beta phosphorylation and IkappaB-alpha degradation with a concomitant increase in NF-kappaB nuclear translocation. Experiments carried out in HEK 293T cells stably expressing TLR3 or TLR4 confirmed that inhibition of PI3K activity enhances NF-kappaB-dependent promoters as well as IFN-beta promoter activities without interfering with transcription at the positive regulatory domain III-I. Furthermore, wortmannin enhanced NF-kappaB activity induced by TRIF overexpression in HEK 293T cells, while overexpression of catalytically active PI3K selectively attenuated TRIF-mediated NF-kappaB transcriptional activity. Finally, in co-immunoprecipitation experiments, we showed that PI3K physically interacted with TRIF. We conclude that inhibition of PI3K activity enhances TRIF-dependent NF-kappaB activity, and thereby increases IFN-beta synthesis elicited by TLR3 or TLR4 ligands.

  20. DMPD: Nuclear factor-kappaB: activation and regulation during toll-like receptorsignaling. [Dynamic Macrophage Pathway CSML Database

    Lifescience Database Archive (English)

    Full Text Available 17349209 Nuclear factor-kappaB: activation and regulation during toll-like receptor...signaling. Carmody RJ, Chen YH. Cell Mol Immunol. 2007 Feb;4(1):31-41. (.png) (.svg) (.html) (.csml) Show Nuclear... factor-kappaB: activation and regulation during toll-like receptorsignaling. PubmedID 17349209 Title Nuclear

  1. High mobility group box protein-1 promotes cerebral edema after traumatic brain injury via activation of toll-like receptor 4.

    Science.gov (United States)

    Laird, Melissa D; Shields, Jessica S; Sukumari-Ramesh, Sangeetha; Kimbler, Donald E; Fessler, R David; Shakir, Basheer; Youssef, Patrick; Yanasak, Nathan; Vender, John R; Dhandapani, Krishnan M

    2014-01-01

    Traumatic brain injury (TBI) is a major cause of mortality and morbidity worldwide. Cerebral edema, a life-threatening medical complication, contributes to elevated intracranial pressure (ICP) and a poor clinical prognosis after TBI. Unfortunately, treatment options to reduce post-traumatic edema remain suboptimal, due in part, to a dearth of viable therapeutic targets. Herein, we tested the hypothesis that cerebral innate immune responses contribute to edema development after TBI. Our results demonstrate that high-mobility group box protein 1 (HMGB1) was released from necrotic neurons via a NR2B-mediated mechanism. HMGB1 was clinically associated with elevated ICP in patients and functionally promoted cerebral edema after TBI in mice. The detrimental effects of HMGB1 were mediated, at least in part, via activation of microglial toll-like receptor 4 (TLR4) and the subsequent expression of the astrocytic water channel, aquaporin-4 (AQP4). Genetic or pharmacological (VGX-1027) TLR4 inhibition attenuated the neuroinflammatory response and limited post-traumatic edema with a delayed, clinically implementable therapeutic window. Human and rodent tissue culture studies further defined the cellular mechanisms demonstrating neuronal HMGB1 initiates the microglial release of interleukin-6 (IL-6) in a TLR4 dependent mechanism. In turn, microglial IL-6 increased the astrocytic expression of AQP4. Taken together, these data implicate microglia as key mediators of post-traumatic brain edema and suggest HMGB1-TLR4 signaling promotes neurovascular dysfunction after TBI.

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

    Science.gov (United States)

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

    2015-04-01

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

  3. Pyrexia, anorexia, adipsia, and depressed motor activity in rats during systemic inflammation induced by the Toll-like receptors-2 and -6 agonists MALP-2 and FSL-1.

    Science.gov (United States)

    Hübschle, Thomas; Mütze, Jörg; Mühlradt, Peter F; Korte, Stefan; Gerstberger, Rüdiger; Roth, Joachim

    2006-01-01

    Macrophage-activating lipopeptide-2 (MALP-2) from Mycoplasma fermentans has been identified as a pathogen-associated molecular pattern of Mycoplasmas that causes activation of the innate immune system through the activation of the heterodimeric Toll-like receptors (TLRs)-2 and -6. The aim of this study was to characterize the ability of MALP-2 and a synthetic analog fibroblast-stimulating lipopeptide-1 (FSL-1; represents the NH2-terminal sequence of a lipoprotein from M. salivarium) to act as exogenous pyrogens, to induce formation of cytokines (endogenous pyrogens), and to cause sickness behavior, such as depressed motor activity, anorexia, and adipsia. For this purpose, body temperature, activity, food intake, and water intake were recorded for 3 days by use of telemetry devices in several groups of rats treated with MALP-2/FSL-1 or the respective control solutions. Intraperitoneal injections of FSL-1 caused fever at doses of 10 or 100 microg/kg, which was preceded by a pronounced phase of hypothermia in response to a dose of 1,000 microg/kg. The maximal fever (a peak of 1.5 degrees C above baseline) was caused by the 100 microg/kg dose with almost identical responses to both MALP-2 and FSL-1. Fever was accompanied by pronounced rises of the proinflammatory cytokines TNF and IL-6 in plasma. Treatment with the TLR-2 and -6 agonists further induced a dose-dependent manifestation of anorexia and adipsia, as well as a reduction of motor activity. We could thus demonstrate that activation of TLR-2 and -6 can induce systemic inflammation in rats accompanied by the classical signs of brain-controlled illness responses.

  4. The application of Toll like receptors for cancer therapy

    Directory of Open Access Journals (Sweden)

    Eui Young So, Toru Ouchi

    2010-01-01

    Full Text Available Toll-like receptor (TLR proteins play key roles in immune responses against infection. Using TLR proteins, host can recognize the conserved molecular structures found in pathogens called pathogen-associated molecular patterns (PAMPs. At the same time, some TLRs are able to detect specific host molecules, such as high-mobility group box protein 1 (HMGB1 and heat shock proteins (hsp, and lead to inflammatory responses. Thus, it has been suggested that TLRs are involved in the development of many pathogenic conditions. Recent advances in TLR-related research not only provide us with scientific information, but also show the therapeutic potential against diseases, such as autoimmune disease and cancer. In this mini review, we demonstrate how TLRs pathways could be involved in cancer development and their therapeutic application, and discuss recent patentable subjects, in particular, that are targeting this unique pathway.

  5. Toll-like receptors as targets for immune disorders.

    LENUS (Irish Health Repository)

    Keogh, Brian

    2012-02-01

    Since the identification of the first Toll-like receptor (TLR) in humans in 1997, understanding of the molecular basis for innate immunity has increased significantly. The TLR family and downstream signalling pathways have been extensively characterised, There is now significant evidence suggesting a role for TLRs in human inflammatory and immune diseases such as rheumatoid arthritis, diabetes, allergy\\/asthma and atherosclerosis. Various approaches have been taken to identify novel therapeutic agents targeting TLRs including biologics, small molecules and nucleic acid-based drugs. Several are now being evaluated in the clinic and showing promise against various diseases. This review paper outlines the recent advances in the understanding of TLR biology and highlights novel TLR agonists and antagonists in development for the treatment of immune diseases.

  6. Epstein-Barr virus (EBV)-encoded small RNA is released from EBV-infected cells and activates signaling from toll-like receptor 3

    OpenAIRE

    2009-01-01

    Epstein-Barr virus–encoded small RNA (EBER) is nonpolyadenylated, noncoding RNA that forms stem-loop structure by intermolecular base-pairing, giving rise to double-stranded RNA (dsRNA)–like molecules, and exists abundantly in EBV-infected cells. Here, we report that EBER induces signaling from the Toll-like receptor 3 (TLR3), which is a sensor of viral double-stranded RNA (dsRNA) and induces type I IFN and proinflammatory cytokines. A substantial amount of EBER, which was sufficient to induc...

  7. Mast Cells Induce Vascular Smooth Muscle Cell Apoptosis via a Toll-Like Receptor 4 Activation Pathway.

    NARCIS (Netherlands)

    Dekker, W.K.; Tempel, D.; Bot, I.; Biessen, E.A.; Joosten, L.A.B.; Netea, M.G.; Meer, J.W.M. van der; Cheng, C.; Duckers, H.J.

    2012-01-01

    OBJECTIVE: Activated mast cells (MCs) release chymase, which can induce vascular smooth muscle cell (VSMC) apoptosis leading to plaque destabilization. Because the mechanism through which MCs release chymase in atherosclerosis is unknown, we studied whether MC-associated VSMC apoptosis is regulated

  8. Soluble markers of the Toll-like receptor 4 pathway differentiate between active and latent tuberculosis and are associated with treatment responses.

    Directory of Open Access Journals (Sweden)

    Siri L Feruglio

    Full Text Available BACKGROUND: Biomarkers to differentiate between active tuberculosis (TB and latent TB infection (LTBI and to monitor treatment responses are requested to complement TB diagnostics and control, particularly in patients with multi-drug resistant TB. We have studied soluble markers of the Toll-like-receptor 4 (TLR-4 pathway in various stages of TB disease and during anti-TB treatment. METHODS: Plasma samples from patients with culture confirmed drug-sensitive TB (n = 19 were collected before and after 2, 8 and 24 weeks of efficient anti-TB treatment and in a LTBI group (n = 6. Soluble (s CD14 and myeloid differentiation-2 (MD-2 were analyzed by the Enzyme-linked immunosorbent assay (ELISA. Lipopolysaccharide (LPS was analyzed by the Limulus Amebocyte Lysate colorimetric assay. Nonparametric statistics were applied. RESULTS: Plasma levels of sCD14 (p<0.001, MD-2 (p = 0.036 and LPS (p = 0.069 were elevated at baseline in patients with untreated active TB compared to the LTBI group. MD-2 concentrations decreased after 2 weeks of treatment (p = 0.011, while LPS levels decreased after 8 weeks (p = 0.005. In contrast, sCD14 levels increased after 2 weeks (p = 0.047 with a subsequent modest decrease throughout the treatment period. There was no significant difference in concentrations of any of these markers between patients with pulmonary and extrapulmonary TB or between patients with or without symptoms. CONCLUSION: Our data suggest that plasma levels of LPS, MD-2 and sCD14 can discriminate between active TB and LTBI. A decline in LPS and MD-2 concentrations was associated with response to anti-TB treatment. The clinical potential of these soluble TLR-4 pathway proteins needs to be further explored.

  9. Mechanisms Underlying the Anti-Inflammatory Effects of Clinacanthus nutans Lindau Extracts: Inhibition of Cytokine Production and Toll-Like Receptor-4 Activation.

    Science.gov (United States)

    Mai, Chun W; Yap, Kok S I; Kho, Mee T; Ismail, Nor H; Yusoff, Khatijah; Shaari, Khozirah; Chin, Swee Y; Lim, Erin S H

    2016-01-01

    Clinacanthus nutans has had a long history of use in folk medicine in Malaysia and Southeast Asia; mostly in the relief of inflammatory conditions. In this study, we investigated the effects of different extracts of C. nutans upon lipopolysaccharide (LPS) induced inflammation in order to identify its mechanism of action. Extracts of leaves and stem bark of C. nutans were prepared using polar and non-polar solvents to produce four extracts, namely polar leaf extract (LP), non-polar leaf extract (LN), polar stem extract (SP), and non-polar stem extracts (SN). The extracts were standardized by determining its total phenolic and total flavonoid contents. Its anti-inflammatory effects were assessed on LPS induced nitrite release in RAW264.7 macrophages and Toll-like receptor (TLR-4) activation in TLR-4 transfected human embryonic kidney cells (HEK-Blue(TM)-hTLR4 cells). The levels of inflammatory cytokines (TNF-α, IFN-γ, IL-1β, IL-6, IL-12p40, and IL-17) in treated RAW264.7 macrophages were quantified to verify its anti-inflammatory effects. Western blotting was used to investigate the effect of the most potent extract (LP) on TLR-4 related inflammatory proteins (p65, p38, ERK, JNK, IRF3) in RAW264.7 macrophages. All four extracts produced a significant, concentration-dependent reduction in LPS-stimulated nitric oxide, LPS-induced TLR-4 activation in HEK-Blue(TM)-hTLR4 cells and LPS-stimulated cytokines production in RAW264.7 macrophages. The most potent extract, LP, also inhibited all LPS-induced TLR-4 inflammatory proteins. These results provide a basis for understanding the mechanisms underlying the previously demonstrated anti-inflammatory activity of C. nutans extracts.

  10. Polygonum cuspidatum and its active components inhibit replication of the influenza virus through toll-like receptor 9-induced interferon beta expression.

    Directory of Open Access Journals (Sweden)

    Chao-Jen Lin

    Full Text Available Influenza virus infection is a global public health issue. The effectiveness of antiviral therapies for influenza has been limited by the emergence of drug-resistant viral strains. Therefore, there is an urgent need to identify novel antiviral therapies. Here we tested the effects of 300 traditional Chinese medicines on the replication of various influenza virus strains in a lung cell line, A549, using an influenza-specific luciferase reporter assay. Of the traditional medicines tested, Polygonum cuspidatum (PC and its active components, resveratrol and emodin, were found to attenuate influenza viral replication in A549 cells. Furthermore, they preferentially inhibited the replication of influenza A virus, including clinical strains isolated in 2009 and 2011 in Taiwan and the laboratory strain A/WSN/33 (H1N1. In addition to inhibiting the expression of hemagglutinin and neuraminidase, PC, emodin, and resveratrol also increased the expression of interferon beta (IFN-β through Toll-like receptor 9 (TLR9. Moreover, the anti-viral activity of IFN-β or resveratrol was reduced when the A549 cells were treated with neutralizing anti-IFN-β antibodies or a TLR9 inhibitor, suggesting that IFN-β likely acts synergistically with resveratrol to inhibit H1N1 replication. This potential antiviral mechanism, involving direct inhibition of virus replication and simultaneous activation of the host immune response, has not been previously described for a single antiviral molecule. In conclusion, our data support the use of PC, resveratrol or emodin for inhibiting influenza virus replication directly and via TLR-9-induced IFN-β production.

  11. Mechanisms underlying the anti-inflammatory effects of Clinacanthus nutans Lindau extracts: inhibition of cytokine production and Toll-like receptor-4 activation

    Directory of Open Access Journals (Sweden)

    Chun Wai eMai

    2016-02-01

    Full Text Available Clinacanthus nutans has had a long history of use in folk medicine in Malaysia and Southeast Asia; mostly in the relief of inflammatory conditions. In this study, we investigated the effects of different extracts of C. nutans upon lipopolysaccharide (LPS induced inflammation in order to identify its mechanism of action. Extracts of leaves and stem bark of C. nutans were prepared using polar and non-polar solvents to produce four extracts, namely polar leaf extract (LP, non-polar leaf extract (LN, polar stem extract (SP and non-polar stem extracts (SN. The extracts were standardized by determining its total phenolic and total flavonoid contents. Its anti-inflammatory effects were assessed on LPS induced nitrite release in RAW264.7 macrophages and Toll-like receptor (TLR-4 activation in TLR-4 transfected human embryonic kidney cells (HEK-BlueTM-hTLR4 cells. The levels of inflammatory cytokines (TNF-α, IFN-γ, IL-1β, IL-6, IL-12p40 and IL-17 in treated RAW264.7 macrophages were quantified to verify its anti-inflammatory effects. Western blotting was used to investigate the effect of the most potent extract (LP on TLR-4 related inflammatory proteins (p65, p38, ERK, JNK, IRF3 in RAW264.7 macrophages. All four extracts produced a significant, concentration-dependent reduction in LPS-stimulated nitric oxide, LPS-induced TLR-4 activation in HEK-BlueTM-hTLR4 cells and LPS-stimulated cytokines production in RAW264.7 macrophages. The most potent extract, LP, also inhibited all LPS-induced TLR-4 inflammatory proteins. These results provide a basis for understanding the mechanisms underlying the previously demonstrated anti-inflammatory activity of C. nutans extracts.

  12. Role of toll like receptors in irritable bowel syndrome: differential mucosal immune activation according to the disease subtype.

    Directory of Open Access Journals (Sweden)

    Liliana Belmonte

    Full Text Available BACKGROUND: The irritable bowel syndrome (IBS is a functional gastrointestinal disorder whose pathogenesis is not completely understood. Its high prevalence and the considerable effects on quality of life make IBS a disease with high social cost. Recent studies suggest that low grade mucosal immune activation, increased intestinal permeability and the altered host-microbiota interactions that modulate innate immune response, contribute to the pathophysiology of IBS. However, the understanding of the precise molecular pathophysiology remains largely unknown. METHODOLOGY AND FINDINGS: In this study our objective was to evaluate the TLR expression as a key player in the innate immune response, in the colonic mucosa of IBS patients classified into the three main subtypes (with constipation, with diarrhea or mixed. TLR2 and TLR4 mRNA expression was assessed by real time RT-PCR while TLRs protein expression in intestinal epithelial cells was specifically assessed by flow cytometry and immunofluorescence. Mucosal inflammatory cytokine production was investigated by the multiplex technology. Here we report that the IBS-Mixed subgroup displayed a significant up-regulation of TLR2 and TLR4 in the colonic mucosa. Furthermore, these expressions were localized in the epithelial cells, opening new perspectives for a potential role of epithelial cells in host-immune interactions in IBS. In addition, the increased TLR expression in IBS-M patients elicited intracellular signaling pathways resulting in increased expression of the mucosal proinflammatory cytokines IL-8 and IL1β. CONCLUSIONS: Our results provide the first evidence of differential expression of TLR in IBS patients according to the disease subtype. These results offer further support that microflora plays a central role in the complex pathophysiology of IBS providing novel pharmacological targets for this chronic gastrointestinal disorder according to bowel habits.

  13. Activation of toll-like receptor 4 is necessary for trauma hemorrhagic shock-induced gut injury and polymorphonuclear neutrophil priming.

    Science.gov (United States)

    Reino, Diego C; Palange, David; Feketeova, Elenora; Bonitz, Robert P; Xu, Da Zhong; Lu, Qi; Sheth, Sharvil U; Peña, Geber; Ulloa, Luis; De Maio, Antonio; Feinman, Rena; Deitch, Edwin A

    2012-07-01

    Interactions of toll-like receptors (TLRs) with nonmicrobial factors play a major role in the pathogenesis of early trauma-hemorrhagic shock (T/HS)-induced organ injury and inflammation. Thus, we tested the hypothesis that TLR4 mutant (TLR4 mut) mice would be more resistant to T/HS-induced gut injury and polymorphonuclear neutrophil (PMN) priming than their wild-type littermates and found that both were significantly reduced in the TLR4 mut mice. In addition, the in vivo and ex vivo PMN priming effect of T/HS intestinal lymph observed in the wild-type mice was abrogated in TLR4 mut mice as well the TRIF mut-deficient mice and partially attenuated in Myd88 mice, suggesting that TRIF activation played a more predominant role than MyD88 in T/HS lymph-induced PMN priming. Polymorphonuclear neutrophil depletion studies showed that T/HS lymph-induced acute lung injury was PMN dependent, because lung injury was totally abrogated in PMN-depleted animals. Because the lymph samples were sterile and devoid of endotoxin or bacterial DNA, we investigated whether the effects of T/HS lymph was related to endogenous nonmicrobial TLR4 ligands. High-mobility group box 1 protein 1, heat shock protein 70, heat shock protein 27, and hyaluronic acid all have been implicated in ischemia-reperfusion-induced tissue injury. None of these "danger" proteins appeared to be involved, because their levels were similar between the sham and shock lymph samples. In conclusion, TLR4 activation is important in T/HS-induced gut injury and in T/HS lymph-induced PMN priming and lung injury. However, the T/HS-associated effects of TLR4 on gut barrier dysfunction can be uncoupled from the T/HS lymph-associated effects of TLR4 on PMN priming.

  14. Bordetella adenylate cyclase toxin differentially modulates toll-like receptor-stimulated activation, migration and T cell stimulatory capacity of dendritic cells.

    Directory of Open Access Journals (Sweden)

    Irena Adkins

    Full Text Available Adenylate cyclase toxin (CyaA is a key virulence factor of the whooping cough agent Bordetella pertussis. The toxin targets CD11b-expressing phagocytes and delivers into their cytosol an adenylyl cyclase (AC enzyme that subverts cellular signaling by increasing cAMP levels. In the present study, we analyzed the modulatory effects of CyaA on adhesive, migratory and antigen presenting properties of Toll-like receptor (TLR-activated murine and human dendritic cells (DCs. cAMP signaling of CyaA enhanced TLR-induced dissolution of cell adhesive contacts and migration of DCs towards the lymph node-homing chemokines CCL19 and CCL21 in vitro. Moreover, we examined in detail the capacity of toxin-treated DCs to induce CD4(+ and CD8(+ T cell responses. Exposure to CyaA decreased the capacity of LPS-stimulated DCs to present soluble protein antigen to CD4+ T cells independently of modulation of co-stimulatory molecules and cytokine production, and enhanced their capacity to promote CD4(+CD25(+Foxp3(+ T regulatory cells in vitro. In addition, CyaA decreased the capacity of LPS-stimulated DCs to induce CD8(+ T cell proliferation and limited the induction of IFN-γ producing CD8(+ T cells while enhancing IL-10 and IL-17-production. These results indicate that through activation of cAMP signaling, the CyaA may be mobilizing DCs impaired in T cell stimulatory capacity and arrival of such DCs into draining lymph nodes may than contribute to delay and subversion of host immune responses during B. pertussis infection.

  15. Penehyclidine hydrochloride: a potential drug for treating COPD by attenuating Toll-like receptors

    Directory of Open Access Journals (Sweden)

    Xiao HT

    2012-11-01

    Full Text Available Hong-Tao Xiao,1,* Zhi Liao,2,* Rong-Sheng Tong11Department of Pharmacy, 2Department of Gynecology and Obstetrics, Sichuan Academy of Medical Sciences and Sichuan Provincial People's Hospital, Chengdu, China*These authors contributed equally to this workBackground: The aim of this review was to evaluate and summarize the available scientific information on penehyclidine hydrochloride (PHC for the treatment of chronic obstructive pulmonary disease (COPD as a result of its ability to attenuate Toll-like receptors. Penehyclidine hydrochloride is an anticholinergic drug manufactured in China, with both antimuscarinic and antinicotinic activity. PHC is used widely in the clinic as a reversal agent in cases of organic phosphorus poisoning and soman poisoning, but also may also have an important role as a bronchodilator in the treatment of obstructive airway disease, including asthma and, in particular, COPD.Methods: Our bibliographic sources included the CAPLUS, MEDLINE, REGISTRY, CASREACT, CHEMLIST, CHEMCATS, and CNKI databases, updated to September 2012. In order to assess the data in detail, we used the search terms “penehyclidine hydrochloride,” “COPD,” “muscarinic receptor,” and “toll-like receptors.” Papers were restricted to those published in the English and Chinese languages, and to “paper” and “review” as the document type. Patents were also reviewed.Results: Our survey mainly yielded the results of research on PHC and the mechanisms of COPD. COPD is a preventable and treatable disease with some significant extrapulmonary manifestations that may contribute to its severity in some patients. Recently, it has been shown that muscarinic receptors may interact with Toll-like receptors. Basic and clinical studies of the relationship between the mechanism of action and the effects of PHC in the respiratory tract have been studied by a number of laboratories and institutions. The main advantages of PHC are that it has few M2

  16. The Role of Toll Like Receptors in Pregnancy

    Directory of Open Access Journals (Sweden)

    Elham Amirchaghmaghi

    2013-09-01

    Full Text Available For many years, the innate immunity was of less interest than the adaptive immunity because it was perceived to have secondary importance in the functionality of the immune system. During the past decades, with the advancement of knowledge about innate immune system, interest in innate immunity has grown dramatically and thus its function has been extensively studied. Innate immunity plays fundamental roles in the initiation and induction of adaptive immune responses. It consists of several cells and receptors including natural killer (NK cells, macrophages (MQs, dendritic cells (DCs and pattern recognition receptors (PRRs. Two decades ago, Toll like receptors (TLRs family was known as one of the important PRRs with unique functions especially in protection against invading pathogens. Since the female reproductive tract has access to the outside environment and has a unique interaction with different pathogens whether invading microorganisms or normal flora, allogenic sperm and semi allogenic fetus, it has an essential need for effective immune responses. It has therefore been suggested that TLRs may play important roles in the immune regulation of the female reproductive tract. In addition, it has been demonstrated that immune disturbance may be responsible for some adverse pregnancy outcomes such as preeclampsia (PE, recurrent spontaneous abortion (RSA and intrauterine growth restriction (IUGR. Our focus in this review is to show the importance of TLRs in pregnancy with emphasis on the expression of these receptors in different tissues related to pregnancy.

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

    Science.gov (United States)

    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

  18. Toll-Like Receptor Pathways in Autoimmune Diseases.

    Science.gov (United States)

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

    2016-02-01

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

  19. Gain-of-function mutations in the Toll-like Receptor pathway: TPL2-mediated ERK1/ERK2 MAPK activation, a path to tumorigenesis in lymphoid neoplasms?

    Directory of Open Access Journals (Sweden)

    Simon eRousseau

    2016-05-01

    Full Text Available Lymphoid neoplasms form a family of cancers affecting B-cells, T-cells and NK cells. The Toll-Like Receptor (TLR signalling adapter molecule MYD88 is the most frequently mutated gene in these neoplasms. This signalling adaptor relays signals from TLRs to downstream effector pathways such as the Nuclear Factor kappa B (NFB and Mitogen Activated Protein Kinase (MAPK pathways to regulate innate immune responses (Kawai and Akira, 2010. Gain-of-function mutations such as MYD88[L265P] activate downstream signalling pathways in absence of cognate ligands for TLRs, resulting in increased cellular proliferation and survival. This article reports an analysis of non-synonymous somatic mutations found in the TLR signaling network in lymphoid neoplasms. In accordance with previous reports, mutations map to MYD88 pro-inflammatory signaling and not TRIF-mediated Type I IFN production. Interestingly, the analysis of somatic mutations found downstream of the core TLR-signaling network uncovered a strong association with the ERK1/2 MAPK cascade. In support of this analysis, heterologous expression of MYD88[L265P] in HEK 293 cells led to ERK1/2 MAPK phosphorylation in addition to NFB activation. Moreover, this activation is dependent on the protein kinase Tumour Promoting Locus-2 (TPL-2, activated downstream of the IKK complex. Activation of ERK1/2 would then lead to activation, amongst others, of MYC and hnRNP A1, two proteins previously shown to contribute to tumour formation in lymphoid neoplasms. Taken together, this analysis suggests that TLR-mediated tumorigenesis occurs via the TPL2-mediated ERK1/2 activation. Therefore, the hypothesis proposed is that inhibition of ERK1/2 MAPK activation would prevent tumour growth downstream of MYD88[L265]. It will be interesting to test whether pharmacological inhibitors of this pathway show efficacy in primary tumour cells derived from hematologic malignancies such as Waldenstrom’s Macroglobulinemia, where the

  20. Role of toll-like receptor 2 and toll-like receptor 4 in post-ischemic coronary endothelial dysfunction in mice

    Institute of Scientific and Technical Information of China (English)

    J.FAVRE; P.MUSETTE; JPHENRY; C.THUILLEZ; V.RICHARD

    2004-01-01

    AIM: A growing body of evidence suggests a role of the toll-like receptors (TLR) in inflammatory processes. In addition to LPS,TLR are activated by many endogenous ligands such as heat shock proteins and oxygeil-derived free radicals which are both produced during cardiac ischemia-reperfusion (I/R). Among TLR,TLR-2 and TLR-4 are expressed in endothelial and myocardial cells and appear to regulate neutrophil-endothelial interactions.Since neutrophil adhesion is a critical event in endothelial injury

  1. Exploitation of the Toll-like receptor system in cancer: a doubled-edged sword?

    LENUS (Irish Health Repository)

    Killeen, S D

    2012-02-03

    The toll-like receptor (TLR) system constitutes a pylogenetically ancient, evolutionary conserved, archetypal pattern recognition system, which underpins pathogen recognition by and activation of the immune system. Toll-like receptor agonists have long been used as immunoadjuvants in anti cancer immunotherapy. However, TLRs are increasingly implicated in human disease pathogenesis and an expanding body of both clinical and experimental evidence suggests that the neoplastic process may subvert TLR signalling pathways to advance cancer progression. Recent discoveries in the TLR system open a multitude of potential therapeutic avenues. Extrapolation of such TLR system manipulations to a clinical oncological setting demands care to prevent potentially deleterious activation of TLR-mediated survival pathways. Thus, the TLR system is a double-edge sword, which needs to be carefully wielded in the setting of neoplastic disease.

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

    Science.gov (United States)

    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.

  3. A toll-like receptor 2 pathway regulates the Ppargc1a/b metabolic co-activators in mice with Staphylococcal aureus sepsis.

    Directory of Open Access Journals (Sweden)

    Timothy E Sweeney

    Full Text Available Activation of the host antibacterial defenses by the toll-like receptors (TLR also selectively activates energy-sensing and metabolic pathways, but the mechanisms are poorly understood. This includes the metabolic and mitochondrial biogenesis master co-activators, Ppargc1a (PGC-1α and Ppargc1b (PGC-1β in Staphylococcus aureus (S. aureus sepsis. The expression of these genes in the liver is markedly attenuated inTLR2(-/- mice and markedly accentuated in TLR4(-/- mice compared with wild type (WT mice. We sought to explain this difference by using specific TLR-pathway knockout mice to test the hypothesis that these co-activator genes are directly regulated through TLR2 signaling. By comparing their responses to S. aureus with WT mice, we found that MyD88-deficient and MAL-deficient mice expressed hepatic Ppargc1a and Ppargc1b normally, but that neither gene was activated in TRAM-deficient mice. Ppargc1a/b activation did not require NF-kβ, but did require an interferon response factor (IRF, because neither gene was activated in IRF-3/7 double-knockout mice in sepsis, but both were activated normally in Unc93b1-deficient (3d mice. Nuclear IRF-7 levels in TLR2(-/- and TLR4(-/- mice decreased and increased respectively post-inoculation and IRF-7 DNA-binding at the Ppargc1a promoter was demonstrated by chromatin immunoprecipitation. Also, a TLR2-TLR4-TRAM native hepatic protein complex was detected by immunoprecipitation within 6 h of S. aureus inoculation that could support MyD88-independent signaling to Ppargc1a/b. Overall, these findings disclose a novel MyD88-independent pathway in S. aureus sepsis that links TLR2 and TLR4 signaling in innate immunity to Ppargc1a/b gene regulation in a critical metabolic organ, the liver, by means of TRAM, TRIF, and IRF-7.

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

    Institute of Scientific and Technical Information of China (English)

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

    2010-01-01

    This article reviews the evidence that ties the development of hepatocellular carcinoma (HCC) to the natural immune pro-inflammatory response to chronic liver disease, with a focus on the role of Toll-like receptor (TLR) signaling as the mechanism of liver stem cell/progenitor transformation to HCC. Two exemplary models of this phenomenon are reviewed in detail. One model applies chronic ethanol/lipopolysaccharide feeding to the activated TLR4 signaling pathway. The other applies chronic feeding of a carcin...

  5. Integrated Regulation of Toll-like Receptor Responses by Notch and Interferon-γ Pathways

    OpenAIRE

    2008-01-01

    Toll-like receptor (TLR) responses are regulated to avoid toxicity and achieve coordinated responses appropriate for the cell environment. We found that Notch and TLR pathways cooperated to activate canonical Notch target genes, including transcriptional repressors Hes1 and Hey1, and to increase production of canonical TLR-induced cytokines TNF, IL-6 and IL-12. Cooperation by these pathways to increase target gene expression was mediated the Notch pathway component and transcription factor RB...

  6. The co-stimulatory effects of MyD88-dependent Toll-like receptor signaling on activation of murine γδ T cells.

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    Jinping Zhang

    Full Text Available γδ T cells express several different toll-like receptor (TLRs. The role of MyD88- dependent TLR signaling in TCR activation of murine γδ T cells is incompletely defined. Here, we report that Pam3CSK4 (PAM, TLR2 agonist and CL097 (TLR7 agonist, but not lipopolysaccharide (TLR4 agonist, increased CD69 expression and Th1-type cytokine production upon anti-CD3 stimulation of γδ T cells from young adult mice (6-to 10-week-old. However, these agonists alone did not induce γδ T cell activation. Additionally, we noted that neither PAM nor CL097 synergized with anti-CD3 in inducing CD69 expression on γδ T cells of aged mice (21-to 22-month-old. Compared to young γδ T cells, PAM and CL097 increased Th-1 type cytokine production with a lower magnitude from anti-CD3- stimulated, aged γδ T cells. Vγ1+ and Vγ4+ cells are two subpopulations of splenic γδ T cells. PAM had similar effects in anti-CD3-activated control and Vγ4+ subset- depleted γδ T cells; whereas CL097 induced more IFN-γ production from Vγ4+ subset-depleted γδ T cells than from the control group. Finally, we studied the role of MyD88-dependent TLRs in γδ T cell activation during West Nile virus (WNV infection. γδ T cell, in particular, Vγ1+ subset expansion was significantly reduced in both MyD88- and TLR7- deficient mice. Treatment with TLR7 agonist induced more Vγ1+ cell expansion in wild-type mice during WNV infection. In summary, these results suggest that MyD88-dependent TLRs provide co-stimulatory signals during TCR activation of γδ T cells and these have differential effects on distinct subsets.

  7. Microbiota regulates type 1 diabetes through Toll-like receptors.

    Science.gov (United States)

    Burrows, Michael P; Volchkov, Pavel; Kobayashi, Koichi S; Chervonsky, Alexander V

    2015-08-11

    Deletion of the innate immune adaptor myeloid differentiation primary response gene 88 (MyD88) in the nonobese diabetic (NOD) mouse model of type 1 diabetes (T1D) results in microbiota-dependent protection from the disease: MyD88-negative mice in germ-free (GF), but not in specific pathogen-free conditions develop the disease. These results could be explained by expansion of particular protective bacteria ("specific lineage hypothesis") or by dominance of negative (tolerizing) signaling over proinflammatory signaling ("balanced signal hypothesis") in mutant mice. Here we found that colonization of GF mice with a variety of intestinal bacteria was capable of reducing T1D in MyD88-negative (but not wild-type NOD mice), favoring the balanced signal hypothesis. However, the receptors and signaling pathways involved in prevention or facilitation of the disease remained unknown. The protective signals triggered by the microbiota were revealed by testing NOD mice lacking MyD88 in combination with knockouts of several critical components of innate immune sensing for development of T1D. Only MyD88- and TIR-domain containing adapter inducing IFN β (TRIF) double deficient NOD mice developed the disease. Thus, TRIF signaling (likely downstream of Toll-like receptor 4, TLR4) serves as one of the microbiota-induced tolerizing pathways. At the same time another TLR (TLR2) provided prodiabetic signaling by controlling the microbiota, as reduction in T1D incidence caused by TLR2 deletion was reversed in GF TLR2-negative mice. Our results support the balanced signal hypothesis, in which microbes provide signals that both promote and inhibit autoimmunity by signaling through different receptors, including receptors of the TLR family.

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

    Science.gov (United States)

    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.

  9. Calpain Activity and Toll-Like Receptor 4 Expression in Platelet Regulate Haemostatic Situation in Patients Undergoing Cardiac Surgery and Coagulation in Mice

    Directory of Open Access Journals (Sweden)

    Jui-Chi Tsai

    2014-01-01

    Full Text Available Human platelets express Toll-like receptors (TLR 4. However, the mechanism by which TLR4 directly affects platelet aggregation and blood coagulation remains to be explored. Therefore, in this study, we evaluated the platelet TLR4 expression in patients who underwent CABG surgery; we explored the correlation between platelet TLR4 expression and the early outcomes in hospital of patients. Additionally, C57BL/6 and C57BL/6-TlrLPS−/− mice were used to explore the roles of platelet TLR4 in coagulation by platelet aggregometry and rotation thromboelastometry. In conclusion, our results highlight the important roles of TLR4 in blood coagulation and platelet function. Of clinical relevance, we also explored novel roles for platelet TLR4 that are associated with early outcomes in cardiac surgery.

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

    Science.gov (United States)

    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

  11. Expression of soluble Toll-like receptors in pleural effusions

    Institute of Scientific and Technical Information of China (English)

    YANG Hai-bo; XIE Kai-qing; DENG Jing-min; QIN Shou-ming

    2010-01-01

    Background The Toll-like receptors (TLRs) represent a group of single-pass transmembrane receptors expressed on sentinel cells that are central to innate immune responses.The aim of this study was to investigate the presence of soluble TLRs in pleural effusions, and the diagnostic values of TLRs for pleural effusion with various etiologies.Methods Pleural effusion and serum samples were collected from 102 patients (36 with malignant pleural effusion, 36with tuberculous pleural effusion, 18 with bacterial pleural effusion, and 12 with transudative pleural effusion).The concentrations of TLR1 to TLR10 were determined in effusion and serum samples by enzyme linked immunosorbent assay.Four classical parameters (protein, lactate dehydrogenase, glucose and C-reactive protein (CRP)) in the pleural fluid were also assessed.Receiver-operating characteristic curves were used to assess the sensitivity and specificity of pleural fluid TLRs and biochemical parameters for differentiating bacterial pleural effusion.Results The concentrations of TLR1, TLR3, TLR4, TLR7 and TLR9 in bacterial pleural effusion were significantly higher than those in malignant, tuberculous, and transudative groups, respectively.Analysis of receiver operating characteristic curves revealed that the area under the curves of TLR1, TLR3, TLR4, TLR7 and TLR9 were 0.831, 0.843,0.842, 0.883 and 0.786, respectively, suggesting that these TLRs play a role in the diagnosis of bacterial pleural effusion.Also, the diagnostic value of TLRs for bacterial pleural effusions was much better than that of biochemical parameters (protein, lactate dehydrogenase, glucose and CRP).Conclusions The concentrations of TLR1, TLR3, TLR4, TLR7 and TLR9 appeared to be increased in bacterial pleural effusion compared to non-bacterial pleural effusions.Determination of these pleural TLRs may improve the ability of clinicians to differentiate pleural effusion patients of bacterial origin from those with other etiologies.

  12. DMPD: Translational mini-review series on Toll-like receptors: recent advances inunderstanding the role of Toll-like receptors in anti-viral immunity. [Dynamic Macrophage Pathway CSML Database

    Lifescience Database Archive (English)

    Full Text Available 17223961 Translational mini-review series on Toll-like receptors: recent advances i...147(2):217-26. (.png) (.svg) (.html) (.csml) Show Translational mini-review series on Toll-like receptors: r...nity. PubmedID 17223961 Title Translational mini-review series on Toll-like receptors: recent advances inund

  13. Up-regulation of Toll-like receptors 2, 3 and 4 in allergic rhinitis

    Directory of Open Access Journals (Sweden)

    Uddman Rolf

    2005-09-01

    Full Text Available Abstract Background Toll-like receptors enable the host to recognize a large number of pathogen-associated molecular patterns such as bacterial lipopolysaccharide, viral RNA, CpG-containing DNA and flagellin. Toll-like receptors have also been shown to play a pivotal role in both innate and adaptive immune responses. The role of Toll-like receptors as a primary part of our microbe defense system has been shown in several studies, but their possible function as mediators in allergy and asthma remains to be established. The present study was designed to examine the expression of Toll-like receptors 2, 3 and 4 in the nasal mucosa of patients with intermittent allergic rhinitis, focusing on changes induced by exposure to pollen. Methods 27 healthy controls and 42 patients with seasonal allergic rhinitis volunteered for the study. Nasal biopsies were obtained before and during pollen season as well as before and after allergen challenge. The seasonal material was used for mRNA quantification of Toll-like receptors 2, 3 and 4 with real-time polymerase chain reaction, whereas specimens achieved in conjunction with allergen challenge were used for immunohistochemical localization and quantification of corresponding proteins. Results mRNA and protein representing Toll-like receptors 2, 3 and 4 could be demonstrated in all specimens. An increase in protein expression for all three receptors could be seen following allergen challenge, whereas a significant increase of mRNA only could be obtained for Toll-like receptor 3 during pollen season. Conclusion The up-regulation of Toll-like receptors 2, 3 and 4 in the nasal mucosa of patients with symptomatic allergic rhinitis supports the idea of a role for Toll-like receptors in allergic airway inflammation.

  14. Toll-like receptor 2 agonists inhibit human fibrocyte differentiation

    Directory of Open Access Journals (Sweden)

    Maharjan Anu S

    2010-11-01

    Full Text Available Abstract Background In healing wounds, some monocytes enter the wound and differentiate into fibroblast-like cells called fibrocytes. Since Toll-like receptors (TLRs are present on monocytes, and pathogens that can infect a wound have and/or release TLR agonists, we examined whether TLR agonists affect fibrocyte differentiation. Results When human peripheral blood mononuclear cells (PBMCs were cultured with TLR3, TLR4, TLR5, TLR7, TLR8 or TLR9 agonists, there was no significant effect on fibrocyte differentiation, even though enhanced extracellular tumor necrosis factor (TNF-α accumulation and/or increased cell surface CD86 or major histocompatibility complex (MHC class II levels were observed. However, all TLR2 agonists tested inhibited fibrocyte differentiation without any significant effect on cell survival. Adding TLR2 agonists to purified monocytes had no effect on fibrocyte differentiation. However, some TLR2 agonists caused PBMCs to secrete a factor that inhibits the differentiation of purified monocytes into fibrocytes. This factor is not interferon (IFN-α, IFN-γ, interleukin (IL-12, aggregated immunoglobulin G (IgG or serum amyloid P (SAP, factors known to inhibit fibrocyte differentiation. TLR2 agonist-treated PBMCs secrete low levels of IL-6, TNF-α, IFN-γ, granulocyte colony-stimulating factor and tumor growth factor β1, but combinations of these factors had no effect on fibrocyte differentiation from purified monocytes. Conclusions Our results indicate that TLR2 agonists indirectly inhibit fibrocyte differentiation and that, for some TLR2 agonists, this inhibition involves other cell types in the PBMC population secreting an unknown factor that inhibits fibrocyte differentiation. Together, these data suggest that the presence of some bacterial signals can inhibit fibrocyte differentiation and may thus slow wound closure.

  15. Involvement of Toll-like receptor 4 in acetaminophen hepatotoxicity.

    Science.gov (United States)

    Yohe, Herbert C; O'Hara, Kimberley A; Hunt, Jane A; Kitzmiller, Tamar J; Wood, Sheryl G; Bement, Jenna L; Bement, William J; Szakacs, Juliana G; Wrighton, Steven A; Jacobs, Judith M; Kostrubsky, Vsevolod; Sinclair, Peter R; Sinclair, Jacqueline F

    2006-06-01

    The objective of this study was to determine whether Toll-like receptor 4 (TLR4) has a role in alcohol-mediated acetaminophen (APAP) hepatotoxicity. TLR4 is involved in the inflammatory response to endotoxin. Others have found that ethanol-mediated liver disease is decreased in C3H/HeJ mice, which have a mutated TLR4 resulting in a decreased response to endotoxin compared with endotoxin-responsive mice. In the present study, short-term (1 wk) pretreatment with ethanol plus isopentanol, the predominant alcohols in alcoholic beverages, caused no histologically observed liver damage in either C3H/HeJ mice or endotoxin-responsive C3H/HeN mice, despite an increase in nitrotyrosine levels in the livers of C3H/HeN mice. In C3H/HeN mice pretreated with the alcohols, subsequent exposure to APAP caused a transient decrease in liver nitrotyrosine formation, possibly due to competitive interaction of peroxynitrite with APAP producing 3-nitroacetaminophen. Treatment with APAP alone resulted in steatosis in addition to congestion and necrosis in both C3H/HeN and C3H/HeJ mice, but the effects were more severe in endotoxin-responsive C3H/HeN mice. In alcohol-pretreated endotoxin-responsive C3H/HeN mice, subsequent exposure to APAP resulted in further increases in liver damage, including severe steatosis, associated with elevated plasma levels of TNF-alpha. In contrast, alcohol pretreatment of C3H/HeJ mice caused little to no increase in APAP hepatotoxicity and no increase in plasma TNF-alpha. Portal blood endotoxin levels were very low and were not detectably elevated by any of the treatments. In conclusion, this study implicates a role of TLR4 in APAP-mediated hepatotoxicity.

  16. DMPD: Toll-like receptor (TLR)-based networks regulate neutrophilic inflammation inrespiratory disease. [Dynamic Macrophage Pathway CSML Database

    Lifescience Database Archive (English)

    Full Text Available 18031251 Toll-like receptor (TLR)-based networks regulate neutrophilic inflammation...l) (.csml) Show Toll-like receptor (TLR)-based networks regulate neutrophilic inflammation inrespiratory dis...ease. PubmedID 18031251 Title Toll-like receptor (TLR)-based networks regulate ne

  17. DMPD: Innate immunity and toll-like receptors: clinical implications of basic scienceresearch. [Dynamic Macrophage Pathway CSML Database

    Lifescience Database Archive (English)

    Full Text Available 15069387 Innate immunity and toll-like receptors: clinical implications of basic science...te immunity and toll-like receptors: clinical implications of basic scienceresearch. PubmedID 15069387 Title... Innate immunity and toll-like receptors: clinical implications of basic sciencer

  18. DMPD: Nucleic acid-sensing Toll-like receptors: beyond ligand search. [Dynamic Macrophage Pathway CSML Database

    Lifescience Database Archive (English)

    Full Text Available 18321608 Nucleic acid-sensing Toll-like receptors: beyond ligand search. Miyake K. ...id-sensing Toll-like receptors: beyond ligand search. PubmedID 18321608 Title Nucleic acid-sensing Toll-like receptors: beyond liga

  19. DMPD: Toll-like receptors, Notch ligands, and cytokines drive the chronicity of lunginflammation. [Dynamic Macrophage Pathway CSML Database

    Lifescience Database Archive (English)

    Full Text Available 18073395 Toll-like receptors, Notch ligands, and cytokines drive the chronicity of ...2007 Dec;4(8):635-41. (.png) (.svg) (.html) (.csml) Show Toll-like receptors, Notch ligands, and cytokines d...rive the chronicity of lunginflammation. PubmedID 18073395 Title Toll-like receptors, Notch liga

  20. DMPD: Toll-like receptors: novel pharmacological targets for the treatment ofneurological diseases. [Dynamic Macrophage Pathway CSML Database

    Lifescience Database Archive (English)

    Full Text Available 17974478 Toll-like receptors: novel pharmacological targets for the treatment ofneu...png) (.svg) (.html) (.csml) Show Toll-like receptors: novel pharmacological targets for the treatment ofneur...ological diseases. PubmedID 17974478 Title Toll-like receptors: novel pharmacological targets for the trea...tment ofneurological diseases. Authors Marsh BJ, Stenzel-Poore MP. Publication Curr

  1. DMPD: The negative regulation of Toll-like receptor and associated pathways. [Dynamic Macrophage Pathway CSML Database

    Lifescience Database Archive (English)

    Full Text Available 17621314 The negative regulation of Toll-like receptor and associated pathways. Lan...) Show The negative regulation of Toll-like receptor and associated pathways. PubmedID 17621314 Title The ne...gative regulation of Toll-like receptor and associated pathways. Authors Lang T,

  2. DMPD: Toll-like receptors are key participants in innate immune responses. [Dynamic Macrophage Pathway CSML Database

    Lifescience Database Archive (English)

    Full Text Available 18064347 Toll-like receptors are key participants in innate immune responses. Aranc...Epub 2007 Nov 21. (.png) (.svg) (.html) (.csml) Show Toll-like receptors are key participants in innate immu...ne responses. PubmedID 18064347 Title Toll-like receptors are key participants in

  3. Toll-like receptors are potential therapeutic targets in rheumatoid arthritis

    Institute of Scientific and Technical Information of China (English)

    Siamak; Sandoghchian; Shotorbani

    2011-01-01

    Toll-like receptors (TLRs) are found on the membranes of pattern recognition receptors and not only play important roles in activating immune responses but are also involved in the pathogenesis of inflammatory disease, injury and cancer. Furthermore, TLRs are also able to recognize endogenous alarmins released by damaged tissue and necrosis and/or apoptotic cells and are present in numerous autoimmune diseases. Therefore, the release of endogenous TLR ligands plays an important role in initiating and driving inflammatory diseases. Increasing data suggest a role for TLR signaling in rheumatoid arthritis, which is an autoimmune disease. Although their involvement is not comprehensively understood, the TLRs signaling transducers may provide potential therapeutic targets.

  4. Anti-inflammatory effects of cordycepin in lipopolysaccharide-stimulated RAW 264.7 macrophages through Toll-like receptor 4-mediated suppression of mitogen-activated protein kinases and NF-κB signaling pathways

    Directory of Open Access Journals (Sweden)

    Choi YH

    2014-10-01

    Full Text Available Yung Hyun Choi,1,2 Gi-Young Kim,3 Hye Hyeon Lee4 1Department of Biochemistry, Dongeui University College of Korean Medicine, Busan, 2Anti-Aging Research Center and Blue-Bio Industry RIC, Dongeui University, Busan, 3Laboratory of Immunobiology, Department of Marine Life Sciences, Jeju National University, Jeju, 4Daegu Gyeongbuk Institute of Science and Technology, Daegu, Republic of Korea Abstract: Cordycepin is the main functional component of the Cordyceps species, which has been widely used in traditional Oriental medicine. This compound possesses many pharmacological properties, such as an ability to enhance immune function, as well as antioxidant, antiaging, and anticancer effects. In the present study, we investigated the anti-inflammatory effects of cordycepin using a murine macrophage RAW 264.7 cell model. Our data demonstrated that cordycepin suppressed production of proinflammatory mediators such as nitric oxide (NO and prostaglandin E2 by inhibiting inducible NO synthase and cyclooxygenase-2 gene expression. Cordycepin also inhibited the release of proinflammatory cytokines, including tumor necrosis factor-alpha and interleukin-1-beta, through downregulation of respective mRNA expression. In addition, pretreatment with cordycepin significantly inhibited lipopolysaccharide (LPS-induced phosphorylation of mitogen-activating protein kinases and attenuated nuclear translocation of NF-κB by LPS, which was associated with abrogation of inhibitor kappa B-alpha degradation. Furthermore, cordycepin potently inhibited the binding of LPS to macrophages and LPS-induced Toll-like receptor 4 and myeloid differentiation factor 88 expression. Taken together, the results suggest that the inhibitory effects of cordycepin on LPS-stimulated inflammatory responses in RAW 264.7 macrophages are associated with suppression of mitogen-activating protein kinases and activation of NF-κB by inhibition of the Toll-like receptor 4 signaling pathway. Keywords

  5. DMPD: The Toll-like receptors: analysis by forward genetic methods. [Dynamic Macrophage Pathway CSML Database

    Lifescience Database Archive (English)

    Full Text Available ods. Authors Beutler B. Publication Immunogenetics. 2005 Jul;57(6):385-92. Pathwa...y forward genetic methods. PubmedID 16001129 Title The Toll-like receptors: analysis by forward genetic meth

  6. Ligands, cell-based models, and readouts required for Toll-like receptor action.

    LENUS (Irish Health Repository)

    Dellacasagrande, Jerome

    2012-02-01

    This chapter details the tools that are available to study Toll-like receptor (TLR) biology in vitro. This includes ligands, host cells, and readouts. The use of modified TLRs to circumvent some technical problems is also discussed.

  7. Histamine Regulates Actin Cytoskeleton in Human Toll-like Receptor 4-activated Monocyte-derived Dendritic Cells Tuning CD4+ T Lymphocyte Response.

    Science.gov (United States)

    Aldinucci, Alessandra; Bonechi, Elena; Manuelli, Cinzia; Nosi, Daniele; Masini, Emanuela; Passani, Maria Beatrice; Ballerini, Clara

    2016-07-08

    Histamine, a major mediator in allergic diseases, differentially regulates the polarizing ability of dendritic cells after Toll-like receptor (TLR) stimulation, by not completely explained mechanisms. In this study we investigated the effects of histamine on innate immune reaction during the response of human monocyte-derived DCs (mDCs) to different TLR stimuli: LPS, specific for TLR4, and Pam3Cys, specific for heterodimer molecule TLR1/TLR2. We investigated actin remodeling induced by histamine together with mDCs phenotype, cytokine production, and the stimulatory and polarizing ability of Th0. By confocal microscopy and RT-PCR expression of Rac1/CdC42 Rho GTPases, responsible for actin remodeling, we show that histamine selectively modifies actin cytoskeleton organization induced by TLR4, but not TLR2 and this correlates with increased IL4 production and decreased IFNγ by primed T cells. We also demonstrate that histamine-induced cytoskeleton organization is at least in part mediated by down-regulation of small Rho GTPase CdC42 and the protein target PAK1, but not by down-regulation of Rac1. The presence and relative expression of histamine receptors HR1-4 and TLRs were determined as well. Independently of actin remodeling, histamine down-regulates IL12p70 and CXCL10 production in mDCs after TLR2 and TLR4 stimulation. We also observed a trend of IL10 up-regulation that, despite previous reports, did not reach statistical significance.

  8. Toll-like receptors and cancer: MYD88 mutation and inflammation

    Directory of Open Access Journals (Sweden)

    James Q Wang

    2014-07-01

    Full Text Available Pattern recognition receptors (PRRs expressed on immune cells are crucial for the early detection of invading pathogens, in initiating early innate immune response and in orchestrating the adaptive immune response. PRRs are activated by specific pathogen-associated molecular patterns (PAMPs that are present in pathogenic microbes or nucleic acids of viruses or bacteria. However, inappropriate activation of these PRRs, such as the Toll-like receptors (TLRs, due to genetic lesions or chronic inflammation has been demonstrated to be a major cause of many haematological malignancies. Gain-of-function mutations in the TLR adaptor protein MYD88 found in 39% of the activated B cell type of diffuse large B cell lymphomas (ABC-DLBCL and almost 100% of Waldenström’s macroglobulinemia (WM further highlight the involvement of TLRs in these malignancies. MYD88 mutations result in the chronic activation of TLR signalling pathways, thus the constitutive activation of the transcription factor NFκB to promote cell survival and proliferation. These recent insights into TLR pathway driven malignancies warrant the need for a better understanding of TLRs in cancers and the development of novel anti-cancer therapies targeting TLRs. This review focuses on Toll-like receptors function and signalling in normal or inflammatory conditions, and how mutations can also hijack the TLR signalling pathways to give rise to cancer. Lastly, we discuss how potential therapeutic agents could be used to restore normal responses to TLRs and have long lasting anti-tumour effects.

  9. Toll-Like Receptor Activation by Generalized Modules for Membrane Antigens from Lipid A Mutants of Salmonella enterica Serovars Typhimurium and Enteritidis.

    Science.gov (United States)

    Rossi, Omar; Caboni, Mariaelena; Negrea, Aurel; Necchi, Francesca; Alfini, Renzo; Micoli, Francesca; Saul, Allan; MacLennan, Calman A; Rondini, Simona; Gerke, Christiane

    2016-04-01

    Invasive nontyphoidal Salmonella (iNTS) disease is a neglected disease with high mortality in children and HIV-positive individuals in sub-Saharan Africa, caused primarily by Africa-specific strains of Salmonella enterica serovars Typhimurium and Enteritidis. A vaccine using GMMA (generalized modules for membrane antigens) fromS.Typhimurium andS.Enteritidis containing lipid A modifications to reduce potential in vivo reactogenicity is under development. GMMA with penta-acylated lipid A showed the greatest reduction in the level of cytokine release from human peripheral blood monocytes from that for GMMA with wild-type lipid A. Deletion of the lipid A modification genes msbB and pagP was required to achieve pure penta-acylation. Interestingly, ΔmsbBΔ pagP GMMA from S. Enteritidis had a slightly higher stimulatory potential than those from S. Typhimurium, a finding consistent with the higher lipopolysaccharide (LPS) content and Toll-like receptor 2 (TLR2) stimulatory potential of the former. Also, TLR5 ligand flagellin was found in Salmonella GMMA. No relevant contribution to the stimulatory potential of GMMA was detected even when the flagellin protein FliC from S. Typhimurium was added at a concentration as high as 10% of total protein, suggesting that flagellin impurities are not a major factor for GMMA-mediated immune stimulation. Overall, the stimulatory potential of S. Typhimurium and S. Enteritidis ΔmsbB ΔpagP GMMA was close to that of Shigella sonnei GMMA, which are currently in phase I clinical trials.

  10. Association of Interacting Genes in the Toll-Like Receptor Signaling Pathway and the Antibody Response to Pertussis Vaccination

    NARCIS (Netherlands)

    Kimman, Tjeerd G.; Banus, Sander; Reijmerink, Naomi; Reimerink, Johan; Stelma, Foekje F.; Koppelman, Gerard H.; Thijs, Carel; Postma, Dirkje S.; Kerkhof, Marjan

    2008-01-01

    Background: Activation of the Toll-like receptor (TLR) signaling pathway through TLR4 may be important in the induction of protective immunity against Bordetella pertussis with TLR4-mediated activation of dendritic and B cells, induction of cytokine expression, and reversal of tolerance as crucial s

  11. Role of Toll-like receptors in etiology of selected diseases of the skin

    Directory of Open Access Journals (Sweden)

    Lilianna Kulczycka

    2010-08-01

    Full Text Available Toll-like receptors (TLR play an important role in anti-infectious defense of organisms. So far in humans 10 receptors have been identified. They were classified into five different subfamilies according to their affinity to characteristic ligands. Every receptor has a similar structure (extracellular part, intramembrane part and cytoplasmic part, irrespective of a type of the ligands with which it reacts. Ligands are present on many cell types, including on those which make up the skin. That is why Toll-like receptors are an important part of the cutaneous, non-specific immunologic response. In the review problems associated with the structure and functions of Toll-like receptors are presented. Moreover, the latest information about the role of TLR in the etiology of some dermatoses (psoriasis, atopic dermatitis, acne vulgaris, rosacea, infections, systemic lupus erythematosus, mycosis fungoides is discussed. In addition, therapeutic implications are ¬described.

  12. In vivo activation of toll-like receptor-9 induces an age-dependent abortive lytic cycle reactivation of murine gammaherpesvirus-68.

    Science.gov (United States)

    Ptaschinski, Catherine; Wilmore, Joel; Fiore, Nancy; Rochford, Rosemary

    2010-12-01

    Infection of mice with murine gammaherpesvirus-68 (γHV-68) serves as a model to understand the pathogenesis of persistent viral infections, including the potential for co-infections to modulate viral latency. We have previously found that infection of neonates (8-day-old mice) with γHV-68 resulted in a high level of persistence of the virus in the lungs as well as the spleen, in contrast to infection of adult mice, for which long-term latency was only readily detected in the spleen. In this study we investigated whether stimulation of toll-like receptor (TLR)9 would modulate viral latency in mice infected with γHV-68 in an age-dependent manner. Pups and adult mice were injected with the synthetic TLR9 ligand CpG ODN at 30 dpi, at which time long-term latency has been established. Three days after CpG injection, the lungs and spleens were removed, and a limiting dilution assay was done to determine the frequency of latently infected cells. RNA was extracted to measure viral transcripts using a ribonuclease protection assay. We observed that CpG injection resulted in an increase in the frequency of latently-infected cells in both the lungs and spleens of infected pups, but only in the spleens of infected adult mice. No preformed virus was detected, suggesting that TLR9 stimulation did not trigger complete viral reactivation. When we examined viral gene expression in these same tissues, we observed expression only of the immediate early lytic genes, rta and K3, but not the early DNA polymerase gene or late gB transcript indicative of an abortive reactivation in the spleen. Additionally, mice infected as pups had greater numbers of germinal center B cells in the spleen following CpG injection, whereas CpG stimulated the expansion of follicular zone B cells in adult mice. These data suggest that stimulation of TLR9 differentially modulates gammaherpesvirus latency via an age-dependent mechanism.

  13. [Significance of Toll-like receptors in the pathophysiology of surgical sepsis].

    LENUS (Irish Health Repository)

    Romics, Laszlo Jr

    2012-02-03

    The discovery of Toll-like receptors has substantially changed our knowledge of pathogen recognition. 11 Toll-like receptors have so far been described in humans. These recognize distinct pathogen associated molecular patterns, as well as endogenous ligands and small molecular synthetic compounds. TLRs have a multifunctional role in pathogen-triggered immune responses and represent an important connection between the "innate" and "adaptive" immunity. The role of the TLRs in the recognition of pathogens renders them a key figure in the activation of the immune response during surgical sepsis. However, emerging evidence points to a fundamental role in tumorigenesis, transplantation, wound healing, atherogenesis and inflammatory bowel disease. The aim hence was to review experimental data pertaining to the activation of TLR signalling pathways in conditions associated with surgical sepsis. A systematic review of the literature was undertaken by searching the MEDLINE database for the period 1966-2004 without language restriction. The paper also analyses the possible therapeutic utilization of the TLR signalling pathways in surgical sepsis.

  14. Toll-like receptors as an escape mechanism from the host defense.

    NARCIS (Netherlands)

    Netea, M.G.; Meer, J.W.M. van der; Kullberg, B.J.

    2004-01-01

    Toll-like receptors (TLRs) are probably the most important class of pattern-recognition receptors. Recognition of pathogen-associated molecular patterns (PAMPs) by TLRs, either alone or in heterodimerization with other TLR or non-TLR receptors, induces the production of signals that are responsible

  15. Role of Toll-like receptors in regulatory functions of T and B cells

    Institute of Scientific and Technical Information of China (English)

    CHANG ZongLiang

    2008-01-01

    Pathogens can find their ways to most sites in the host. Pathogen sensors, such as Toll-like receptors (TLRs), must be equally and broadly distributed on immune cells to combat them through innate and adaptive immunity. Most classes of TLRs are found in innate immune cells to obtain an immediate re-sponse against pathogens, but recent studies indicate that a number of TLRs are wildly expressed in T and B cells, suggesting TLRs also directly regulate adaptive immune responses. Due to the rapid in-crease of new information on the multiple roles of TLRs, in this paper we aim to review several main properties of TLRs and their direct role in T and B cells. This review consists of 6 parts: (ⅰ) Characteris-tics of Toll-like receptors (TLRs) and signaling; (ⅱ) signalling pathways of TLRs; (ⅲ) TLR expressions on human leukocytes; (ⅳ) TLR expressions and functions in the Th1, CD4+CD45RO+ memory T cells and regulatory/suppressor T as well as B cell populations; (ⅴ) therapeutic potential of TLR agonists; (ⅵ) discussion and perspective. The latest findings and potential therapeutic applications are discussed. There is growing evidence supporting the concept that TLR activation contributes not only to innate immunity but also to adaptive immunity, including direct regulation of both T and B lymphocytes by TLRs.

  16. Coxsackievirus B3 induces viral myocarditis by upregulating toll-like receptor 4 expression.

    Science.gov (United States)

    Zhao, Zhao; Cai, Tian-Zhi; Lu, Yan; Liu, Wen-Jun; Cheng, Man-Li; Ji, Yu-Qiang

    2015-04-01

    In the present study, we investigated the potential pathogenesis of coxsackievirus B3 (CVB3)-induced viral myocarditis and the promising protective effect of silencing RNA (small interfering RNA, siRNA). One hundred and twenty mice were included in the study, and 30 mice were intraperitoneally inoculated with CVB3 to establish an acute viral myocarditis model. The survival rate was observed for the CVB3-infected mouse model (MOD), and myocardial injury was examined by HE (hematoxylin and eosin) staining assay. Real-time PCR (RT-PCR) and Western blot assay were selected to detect the toll-like receptor 4 (TLR4) expression in myocardial tissues. The TLR4 gene was silenced for the MOD mice, and the effects of this treatment were observed. The results indicate that the expression of TLR4 mRNA and the protein significantly and persistently increased during the progression of CVB3-induced myocarditis. The activities of cardiac enzymes including CK, LDH, AST, and CK-MB were also enhanced in CVB3-induced myocardial tissues. Interestingly, when the TLR4 gene was silenced, the CVB3-induced TLR4 production was significantly decreased and the severity of myocarditis was significantly lessened. In conclusion, CVB3 may induce viral myocarditis by upregulating toll-like receptor 4 expression. The viral myocarditis can be ameliorated by silencing the TLR4 gene in the CVB3 viral myocarditis model, which may be a feasible therapeutic method for treatment of viral myocarditis.

  17. Red blood cell alloimmunization is influenced by the delay between Toll-like receptor agonist injection and transfusion.

    Science.gov (United States)

    Elayeb, Rahma; Tamagne, Marie; Bierling, Philippe; Noizat-Pirenne, France; Vingert, Benoît

    2016-02-01

    Murine models of red blood cell transfusion show that inflammation associated with viruses or methylated DNA promotes red blood cell alloimmunization. In vaccination studies, the intensity of antigen-specific responses depends on the delay between antigen and adjuvant administration, with a short delay limiting immune responses. In mouse models of alloimmunization, the delay between the injection of Toll-like receptor agonists and transfusion is usually short. In this study, we hypothesized that the timing of Toll-like receptor 3 agonist administration affects red blood cell alloimmunization. Poly(I:C), a Toll-like receptor 3 agonist, was administered to B10BR mice at various time points before the transfusion of HEL-expressing red blood cells. For each time point, we measured the activation of splenic HEL-presenting dendritic cells, HEL-specific CD4(+) T cells and anti-HEL antibodies in serum. The phenotype of activated immune cells depended on the delay between transfusion and Toll-like receptor-dependent inflammation. The production of anti-HEL antibodies was highest when transfusion occurred 7 days after agonist injection. The proportion of HEL-presenting CD8α(+) dendritic cells producing interleukin-12 was highest in mice injected with poly(I:C) 3 days before transfusion. Although the number of early-induced HEL-specific CD4(+) T cells was similar between groups, a high proportion of these cells expressed CD134, CD40 and CD44 in mice injected with poly(I:C) 7 days before transfusion. This study clearly shows that the delay between transfusion and Toll-like receptor-induced inflammation influences the immune response to transfused red blood cells.

  18. DMPD: Toll-like receptors: paving the path to T cell-driven autoimmunity? [Dynamic Macrophage Pathway CSML Database

    Lifescience Database Archive (English)

    Full Text Available 17888644 Toll-like receptors: paving the path to T cell-driven autoimmunity? Marsla...nd BJ, Kopf M. Curr Opin Immunol. 2007 Dec;19(6):611-4. Epub 2007 Sep 21. (.png) (.svg) (.html) (.csml) Show Toll-...like receptors: paving the path to T cell-driven autoimmunity? PubmedID 17888644 Title Toll-like recep...tors: paving the path to T cell-driven autoimmunity? Authors Marsland BJ, Kopf M.

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

    Science.gov (United States)

    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.

  20. Toll-Like Receptor 2 as a Regulator of Oral Tolerance in the Gastrointestinal Tract

    Directory of Open Access Journals (Sweden)

    Matthew C. Tunis

    2014-01-01

    Full Text Available Food allergy, other adverse immune responses to foods, inflammatory bowel disease, and eosinophilic esophagitis have become increasingly common in the last 30 years. It has been proposed in the “hygiene hypothesis” that dysregulated immune responses to environmental microbial stimuli may modify the balance between tolerance and sensitization in some patients. Of the pattern recognition receptors that respond to microbial signals, toll-like receptors (TLRs represent the most investigated group. The relationship between allergy and TLR activation is currently at the frontier of immunology research. Although TLR2 is abundant in the mucosal environment, little is known about the complex relationship between bystander TLR2 activation by the commensal microflora and the processing of oral antigens. This review focuses on recent advances in our understanding of the relationship between TLR2 and oral tolerance, with an emphasis on regulatory T cells, eosinophils, B cells, IgA, intestinal regulation, and commensal microbes.

  1. Malassezia-derived indoles activate the aryl hydrocarbon receptor and inhibit Toll-like receptor-induced maturation in monocyte-derived dendritic cells.

    NARCIS (Netherlands)

    Vlachos, C.; Schulte, B.M.; Magiatis, P.; Adema, G.J.; Gaitanis, G.

    2012-01-01

    Background The aryl hydrocarbon receptor (AhR) is a nuclear receptor and transcriptional regulator with pleiotropic effects. The production of potent AhR ligands by Malassezia yeasts, such as indirubin, indolo[3,2-b]carbazole (ICZ), tryptanthrin and malassezin, has been associated with the pathogene

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

    NARCIS (Netherlands)

    Voogdt, Carlos G.P.; Bouwman, Lieneke I.; Kik, Marja J.L.; Wagenaar, Jaap A.; Putten, Van 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 vert

  3. Toll-like receptors in inflammatory bowel disease-stepping into uncharted territory

    Institute of Scientific and Technical Information of China (English)

    Avi Levin; Oren Shibolet

    2008-01-01

    Ulcerative colitis and Crohn's disease are chronic relapsing-remitting inflammatory processes of the intestinaf tract.The etiology of these diseases is currently unknown.However,inflammation is hypothesized to result from inappropriate activation of mucosal immunity luminal antigens in genetically susceptible individuals.Toll-like receptors(TLRs)are a family of transmembrane proteins that act as microbial pattern recognition receptors.They are crucial initiators of innate immune responses.The role of TLRs in the pathogenesis of inflammatory bowel disease(IBD)has not been fully elucidated.In this review,we aim to analyze the available data connecting individual TLRs to intestinal inflammation and IBD.(C)2008 The WJG Press.All rights reserved.

  4. Dynamic evolution of toll-like receptor multigene families in echinoderms

    Directory of Open Access Journals (Sweden)

    Katherine M Buckley

    2012-06-01

    Full Text Available The genome of the purple sea urchin, Strongylocentrotus purpuratus, was the first to be sequenced from a long-lived large invertebrate. Analysis of this genome uncovered a surprisingly complex immune system in which the moderately sized sets of 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 genes, more than 200 Nod-like receptors and 1095 scavenger receptor cysteine-rich domains, a ten-fold expansion relative to vertebrates. Given their stereotypic structure and simple intron-exon architecture, the TLRs are the most tractable of these families for more detailed analysis. An immune defense role for these receptors is suggested by their sequence diversity and expression in immunologically active tissues, including phagocytes. This complexity of the sea urchin TLR multigene families largely derives from expansions that are independent of those in vertebrates and protostomes, although a small family of TLRs with structure similar to that of Drosophila Toll likely originated in an ancient eumetazoan ancestor. Several other invertebrate deuterostome genomes have been sequenced, including the cephalochordate, Branchiostoma floridae and the sea urchin 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 protostome-like sequences are found in L. variegatus. 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 functions and other, more stable, subfamilies that may function similarly to those of vertebrates.

  5. Toll-like receptor 2 activation by β2→1-fructans protects barrier function of t84 human intestinal epithelial cells in a chain length-dependent manner

    NARCIS (Netherlands)

    Vogt, L.M.; Meyer, D.; Pullens, G.; Faas, M.M.; Venema, K.; Ramasamy, U.; Schols, H.A.; Vos, P. de

    2014-01-01

    Dietary fiber intake is associated with lower incidence and mortality from disease, but the underlying mechanisms of these protective effects are unclear.We hypothesized that β2→1-fructan dietary fibers confer protection on intestinal epithelial cell barrier function via Toll-like receptor 2 (TLR2),

  6. Receptores similares a Toll en peces: el inicio de la divergencia Toll-like receptors in fish: the beginning divergence

    Directory of Open Access Journals (Sweden)

    IS Rondón-Barragán

    2009-06-01

    Full Text Available La inmunidad innata utiliza mecanismos de basados en el reconocimiento no clonal de componentes microbianos, denominados PAMPs, mediante el uso de receptores de reconocimiento de patrón genéticamente codificados (e.g. receptores similares a toll. Los PAMPs son estructuras esenciales para la fisiología y supervivencia de los microbios. Los receptores similares a Toll son una familia de receptores de transmembrana tipo I, con un dominio rico en leucina aminoterminal y una cola intracelular carboxiterminal; los cuales son expresados en diversas células incluyendo neutrófilos, macrófagos, células dendríticas, entre otras. Las vías de activación incluyen reclutamiento de proteínas citoplasmáticas adaptadoras que activan kinasas y factores asociados al factor de necrosis tumoral, conllevando a la activación de factores nucleares y a la producción de citoquinas y expresión de moléculas coestimuladoras de superficie en las células presentadoras de antígenos. El conocimiento acerca de los receptores similares a Toll permite el entendimiento de la dinámica de la respuesta inmune así como los procesos involucrados en el reconocimiento de los agentes microbianos. Esta revisión se enfoca en la identificación de los diversos receptores similares a Toll en peces, sus funciones e interacciones con otros así como la homología e identidad entre animales.Innate immunity initiates mechanisms based on the non-clonal recognition of microbial components, so-called PAMPs by using a variety of gene-encoded pattern recognition receptors (e.g. toll-like receptors. PAMPs are essential structures for the physiology and survival of the microbes. Toll-like receptors are transmembrane receptors family type I, with an aminoterminal leucin-rich repeat domain and a carboxiterminal intracellular tail; which are expressed in cells such as neutrophils, macrophages, dendritic cells, as well as others. Activation pathways including the recruitment of

  7. DMPD: Toll-like receptors and RNA helicases: two parallel ways to trigger antiviralresponses. [Dynamic Macrophage Pathway CSML Database

    Lifescience Database Archive (English)

    Full Text Available 16762830 Toll-like receptors and RNA helicases: two parallel ways to trigger antivi...-like receptors and RNA helicases: two parallel ways to trigger antiviralresponses. PubmedID 16762830 Title ...Toll-like receptors and RNA helicases: two parallel ways to trigger antiviralresp

  8. Toll-like receptors and NOD-like receptors in rheumatic diseases.

    LENUS (Irish Health Repository)

    McCormack, William J

    2012-02-01

    The past 10 years have seen the description of families of receptors that drive proinflammatory cytokine production in infection and tissue injury. Two major classes have been examined in the context of inflammatory joint disease--the Toll-like receptors (TLRs) and NOD-like receptors (NLRs). TLRs such as TLR2 and TLR4 are being implicated in the pathology of rheumatoid arthritis, ankylosing spondylitis, lyme arthritis and osteoarthritis. Nalp3 has been identified as a key NLR for IL-1beta production and has been shown to have a particular role in gout. These findings present new therapeutic opportunities, possibly allowing for the replacement of biologics with small molecule inhibitors.

  9. MECHANISMS OF ANTIINFECTIOUS FUNCTIONS OF INNATE IMMUNITY: ROLE OF TOLL-LIKE RECEPTORS

    Directory of Open Access Journals (Sweden)

    S. I. Suskov

    2012-01-01

    Full Text Available This review describes the main role of toll-like receptors of innate immunity for pathogen recognition; signaling; production of inflammatory response. Also Interrelation of innate and adaptive Immunity in conditions of pathology and organ transplantation were considered. 

  10. Relationship between Toll-Like Receptor 8 Gene Polymorphisms and Pediatric Pulmonary Tuberculosis

    Directory of Open Access Journals (Sweden)

    Nazan Dalgic

    2011-01-01

    Full Text Available Objectives: Genetic variants in Toll-like receptors (TLRs are considered a potential indicator for host susceptibility to and outcome of several infectious diseases including tuberculosis. The aim of this study was to determine whether −129 C/G and Met1Val polymorphisms of TLR8 were associated with pediatric pulmonary tuberculosis in Turkish population.

  11. Evolutionary patterns of Toll-like receptor signaling pathway genes in the Suidae

    NARCIS (Netherlands)

    Darfour-Oduro, K.A.; Megens, Hendrik Jan; Roca, A.L.; Groenen, M.A.M.; Schook, L.B.

    2016-01-01

    Background: The Toll-like receptor (TLR) signaling pathway constitutes an essential component of the innate immune system. Highly conserved proteins, indicative of their critical roles in host survival, characterize this pathway. Selective constraints could vary depending on the gene's position w

  12. Identification and functional characterization of nonmammalian Toll-like receptor 20

    NARCIS (Netherlands)

    Pietretti, D.; Scheer, M.H.; Fink, I.R.; Taverne, N.; Savelkoul, H.F.J.; Spaink, H.P.; Forlenza, M.; Wiegertjes, G.

    2014-01-01

    Like other vertebrate Toll-like receptors (TLRs), the TLRs of teleost fish can be subdivided into six major families, each of which recognize a general class of molecular patterns. However, there also are a number of Tlrs with unknown function, the presence of which seems unique to the bony fish, am

  13. Toll-like Receptor 4 Signaling in Ventilator-induced Diaphragm Atrophy.

    NARCIS (Netherlands)

    Schellekens, W.J.M.; Hees, H.W.H. van; Vaneker, M.; Linkels, M.; Dekhuijzen, P.N.R.; Scheffer, G.J.; Hoeven, J.G. van der; Heunks, L.M.A.

    2012-01-01

    BACKGROUND:: Mechanical ventilation induces diaphragm muscle atrophy, which plays a key role in difficult weaning from mechanical ventilation. The signaling pathways involved in ventilator-induced diaphragm atrophy are poorly understood. The current study investigated the role of Toll-like receptor

  14. Toll-like receptor 2 signaling in response to brain injury: an innate bridge to neuroinflammation

    DEFF Research Database (Denmark)

    Babcock, Alicia; Wirenfeldt, Martin; Holm, Thomas

    2006-01-01

    Reactive gliosis is a prominent feature of neurodegenerative and neuroinflammatory disease in the CNS, yet the stimuli that drive this response are not known. There is growing appreciation that signaling through Toll-like receptors (TLRs), which is key to generating innate responses to infection,...... to neuroinflammation. Udgivelsesdato: Dec-6...

  15. Bartonella quintana lipopolysaccharide is a natural antagonist of Toll-like receptor 4.

    NARCIS (Netherlands)

    Popa, C.; Abdollahi-Roodsaz, S.; Joosten, L.A.B.; Takahashi, N.; Sprong, T.; Matera, G.; Liberto, M.C.; Foca, A.; Deuren, M. van; Kullberg, B.J.; Berg, W.B. van den; Meer, J.W.M. van der; Netea, M.G.

    2007-01-01

    Bartonella quintana is a gram-negative microorganism that causes trench fever and chronic bacteremia. B. quintana lipopolysaccharide (LPS) was unable to induce the production of proinflammatory cytokines in human monocytes. Interestingly, B. quintana LPS is a potent antagonist of Toll-like receptor

  16. The Janus face of Bartonella quintana recognition by Toll-like receptors (TLRs): a review.

    NARCIS (Netherlands)

    Matera, G.; Liberto, M.C.; Joosten, L.A.B.; Vinci, M.; Quirino, A.; Pulicari, M.C.; Kullberg, B.J.; Meer, J.W.M. van der; Netea, M.G.; Foca, A.

    2008-01-01

    Bartonella quintana (B. quintana) is a facultative, intracellular bacterium, which causes trench fever, chronic bacteraemia and bacillary angiomatosis. Little is known about the recognition of B. quintana by the innate immune system. In this review, we address the impact of Toll-like receptors (TLRs

  17. Adaptive evolution of Toll-like receptors (TLRs) in the family Suidae

    NARCIS (Netherlands)

    Darfour-Oduro, K.A.; Megens, H.J.W.C.; Roca, A.L.; Groenen, M.A.M.; Schook, L.B.

    2015-01-01

    Members of the family Suidae have diverged over extended evolutionary periods in diverse environments, suggesting that adaptation in response to endemic infectious agents may have occurred. Toll-like receptors (TLRs) comprise a multigene family that acts as the first line of defense against infectio

  18. The complement system and toll-like receptors as integrated players in the pathophysiology of atherosclerosis

    DEFF Research Database (Denmark)

    Hovland, Anders; Jonasson, Lena; Garred, Peter;

    2015-01-01

    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...

  19. Toll-Like Receptor (TLR2 and TLR4) Polymorphisms and Chronic Obstructive Pulmonary Disease

    NARCIS (Netherlands)

    Budulac, S.E.; Boezen, H.M.; Hiemstra, Pieter S.; Lapperre, Therese S.; Vonk, Judith M.; Timens, W.; Postma, D.S.

    2012-01-01

    Toll-like receptors (TLRs) participate in the defence against bacterial infections that are common in patients with Chronic Obstructive Pulmonary Disease (COPD). We studied all tagging SNPs in TLR2 and TLR4 and their associations with the level and change over time of both FEV1 and sputum inflammato

  20. Toll-like receptor 2 ligands regulate monocyte Fcγ receptor expression and function.

    Science.gov (United States)

    Shah, Prexy; Fatehchand, Kavin; Patel, Hemal; Fang, Huiqing; Justiniano, Steven E; Mo, Xiaokui; Jarjoura, David; Tridandapani, Susheela; Butchar, Jonathan P

    2013-04-26

    Fcγ receptor (FcγR) clustering on monocytes/macrophages results in phagocytosis and inflammatory cytokine production, which serve to eliminate antibody-opsonized targets and activate neighboring immune cells. Toll-like receptor 2 (TLR2), which recognizes a range of both bacterial and fungal components, elicits strong proinflammatory responses in these cells when stimulated by ligands, either natural or synthetic. Thus, we explored the possibility that TLR2 agonists could strengthen FcγR activity within the context of antibody therapy. Human peripheral blood monocytes treated with the TLR2 agonist Pam2CSK4 showed significantly enhanced FcγR-mediated cytokine production as well as phagocytic ability. An examination of the molecular mechanism behind this enhancement revealed increased expression of both FcγRIIa and the common γ subunit following Pam2CSK4 treatment. Interestingly however, expression of the inhibitory receptor FcγRIIb was also modestly increased. Further investigation revealed that Pam2CSK4 also dramatically decreased the expression of SHIP, the major mediator of FcγRIIb inhibitory activity. Using a murine Her2/neu solid tumor model of antibody therapy, we found that Pam2CSK4 significantly enhanced the ability of anti-Her2 antibody to reduce the rate of tumor growth. To verify that the FcγR enhancement was not unique to the diacylated Pam2CSK4, we also tested Pam3CSK4, a related triacylated TLR2 agonist. Results showed significant enhancement in FcγR function and expression. Taken together, these findings indicate that TLR2 activation can positively modulate FcγR and suggest that TLR2 agonists should be considered for testing as adjuvants for antitumor antibody therapy.

  1. Toll-like Receptor 2 Ligands Regulate Monocyte Fcγ Receptor Expression and Function*

    Science.gov (United States)

    Shah, Prexy; Fatehchand, Kavin; Patel, Hemal; Fang, Huiqing; Justiniano, Steven E.; Mo, Xiaokui; Jarjoura, David; Tridandapani, Susheela; Butchar, Jonathan P.

    2013-01-01

    Fcγ receptor (FcγR) clustering on monocytes/macrophages results in phagocytosis and inflammatory cytokine production, which serve to eliminate antibody-opsonized targets and activate neighboring immune cells. Toll-like receptor 2 (TLR2), which recognizes a range of both bacterial and fungal components, elicits strong proinflammatory responses in these cells when stimulated by ligands, either natural or synthetic. Thus, we explored the possibility that TLR2 agonists could strengthen FcγR activity within the context of antibody therapy. Human peripheral blood monocytes treated with the TLR2 agonist Pam2CSK4 showed significantly enhanced FcγR-mediated cytokine production as well as phagocytic ability. An examination of the molecular mechanism behind this enhancement revealed increased expression of both FcγRIIa and the common γ subunit following Pam2CSK4 treatment. Interestingly however, expression of the inhibitory receptor FcγRIIb was also modestly increased. Further investigation revealed that Pam2CSK4 also dramatically decreased the expression of SHIP, the major mediator of FcγRIIb inhibitory activity. Using a murine Her2/neu solid tumor model of antibody therapy, we found that Pam2CSK4 significantly enhanced the ability of anti-Her2 antibody to reduce the rate of tumor growth. To verify that the FcγR enhancement was not unique to the diacylated Pam2CSK4, we also tested Pam3CSK4, a related triacylated TLR2 agonist. Results showed significant enhancement in FcγR function and expression. Taken together, these findings indicate that TLR2 activation can positively modulate FcγR and suggest that TLR2 agonists should be considered for testing as adjuvants for antitumor antibody therapy. PMID:23504312

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

    Science.gov (United States)

    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.

  3. Toll-like receptors, a double-edged sword in immunity to malaria

    Institute of Scientific and Technical Information of China (English)

    Chen Jide; He Ying; Xu Wenyue; Huang Fusheng

    2009-01-01

    Toll-like receptors (TLRs) are a central component of innate immune system and play a major role as the initiator of the innate immune responses to defend against bacteria, viruses, parasite and other pathogens. During malaria infection, TLRs signaling pathways are initialed with the recognition of Plasmodium glycosylphosphatidylinositols (GPI) and hemozoin as pathogen-associated molecular patterns (PAMPs). And then, activation of TLRs signaling induces specific biological responses against malaria parasites invasion. However, TLRs are also involved in malaria pathogenesis and enhancement of immune tolerance and evasion for malaria infection. Moreover, malaria parasites regulate selectively TLRs expression on immune cells.Thus, these evidences indicated that TLRs have contrary roles on malaria infection. Understanding the complicated roles of TLRs on malaria infection will contribute us to design more effective anti-malaria drugs or vaccines.

  4. Expression of Toll-like receptors 2 and 4 in gingivitis and chronic periodontitis.

    Directory of Open Access Journals (Sweden)

    Sarah S

    2006-01-01

    Full Text Available Periodontal disease is the major cause of adult tooth loss and is commonly characterized by a chronic inflammation caused by infection by oral bacteria. Members of Toll-like receptor (TLR family recognize conserved microbial structures, such as bacterial lipopolysaccharides, and activate signaling pathways that result in immune responses against microbial infections. The aim of the present study was to assess the mRNA expression of TLR-2 and TLR-4 in gingivitis and chronic periodontitis. Gingival tissue samples were collected from patients with chronic periodontitis, gingivitis, and healthy controls. Total RNA was extracted and RT-PCR was done for TLR-2 and TLR-4. The results showed that TLR-2 was significantly increased in gingivitis compared to TLR-4 expression and decreased in chronic periodontitis.

  5. Regulation of Toll-like receptors-dependent inflammatory response 

    Directory of Open Access Journals (Sweden)

    Ewa Kowalczyk

    2013-03-01

    Full Text Available Toll-like receptors (TLRs are a pivotal part of our innate immune response. They recognize a wide variety of pathogens and instigate an immune response, thus facilitating the removal of the disease-causing agent. Due to the intense nature of this response its strict control is of keyimportance, as a prolonged inflammatory signal leads to carcinogenesis and autoimmune disorders. The signaling cascade initiated by the activated TLR is complex and consists of multiple stages. It involves a variety of adaptor proteins, protein kinases and effector transcription factors. The number of stages in this process enables many possible checkpoints and ways of regulation. Signal modulation involves differentiated expression of TLRs, splicing variants of their adaptorproteins, enzymes modifying proteins engaged in the cascade and many more. This review focuses on endogenous factors responsible for controlling the TLR-dependent inflammatory response as well as on pharmacological therapies designed for regulating the innate immune response.  

  6. Bone marrow and nonbone marrow Toll like receptor 4 regulate acute hepatic injury induced by endotoxemia.

    Directory of Open Access Journals (Sweden)

    Edith Hochhauser

    Full Text Available BACKGROUND: Toll-like receptors (TLRs are expressed in immune cells and hepatocytes. We examined whether hepatic Toll-like receptor 4 (TLR4 is involved in the acute hepatic injury caused by the administration of lipopolysaccharide (LPS (septic shock model. METHODS: Wild type (WT, TLR4-deficient and chimera mice underwent myeloablative bone marrow transplantation to dissociate between TLR4 expression in the liver or in the immune-hematopoietic system. Mice were injected with LPS and sacrificed 4 hours later. RESULTS: Compared to TLR4 deficient mice, WT mice challenged with LPS displayed increased serum liver enzymes and hepatic cellular inflammatory infiltrate together with increased serum and hepatic levels of interleukin 1β (IL-1β, tumor necrosis factor α (TNFα ,Up-regulation of hepatic mRNA encoding TLR4, IκB and c-jun expressions. TLR4 mutant mice transplanted with WT bone marrow were more protected than WT chimeric mice bearing TLR4 mutant hemopoietic cells from LPS, as seen by IL-1β and TNFα levels. We then used hepatocytes (Huh7 and macrophages from monocytic cell lines to detect TLR mRNA expression. Macrophages expressed a significantly higher level of TLR4 mRNA and TLR2 (more than 3000- and 8000-fold respectively compared with the hepatocyte cell line. LPS administration induced TLR4 activation in a hepatocyte cell line in a dose dependent manner while TLR2 mRNA hardly changed. CONCLUSIONS: These results suggest that TLR4 activation of hepatocytes participate in the immediate response to LPS induced hepatic injury. However, in this response, the contribution of TLR4 on bone marrow derived cells is more significant than those of the hepatocytes. The absence of the TLR4 gene plays a pivotal role in reducing hepatic LPS induced injury.

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

    Science.gov (United States)

    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.

  8. Multiplex screening of 22 single-nucleotide polymorphisms in 7 Toll-like receptors: an association study in rheumatoid arthritis

    DEFF Research Database (Denmark)

    Enevold, Christian; Radstake, Timothy R D; Coenen, Marieke J H;

    2010-01-01

    Toll-like receptors (TLR) have been implicated in the pathogenesis of arthritis. We investigated the role of functional variants of TLR in the disease phenotype and severity of rheumatoid arthritis (RA).......Toll-like receptors (TLR) have been implicated in the pathogenesis of arthritis. We investigated the role of functional variants of TLR in the disease phenotype and severity of rheumatoid arthritis (RA)....

  9. Pleiotropic effects of Blastocystis spp. Subtypes 4 and 7 on ligand-specific toll-like receptor signaling and NF-κB activation in a human monocyte cell line.

    Directory of Open Access Journals (Sweden)

    Joshua D W Teo

    Full Text Available Blastocystis spp. is a common enteric stramenopile parasite that colonizes the colon of hosts of a diverse array of species, including humans. It has been shown to compromise intestinal epithelial cell barrier integrity and mediate the production of pro-inflammatory cytokines and chemokines. Mucosal epithelial surfaces, including the intestinal epithelium, are increasingly recognized to perform a vital surveillance role in the context of innate immunity, through the expression of pathogen recognition receptors, such as Toll-like receptors (TLRs. In this study, we use the human TLR reporter monocytic cell line, THP1-Blue, which expresses all human TLRs, to investigate effects of Blastocystis on TLR activation, more specifically the activation of TLR-2, -4 and -5. We have observed that live Blastocystis spp. parasites and whole cell lysate (WCL alone do not activate TLRs in THP1-Blue. Live ST4-WR1 parasites inhibited LPS-mediated NF-κB activation in THP1-Blue. In contrast, ST7-B WCL and ST4-WR1 WCL induced pleiotropic modulation of ligand-specific TLR-2 and TLR-4 activation, with no significant effects on flagellin-mediated TLR-5 activation. Real time-qPCR analysis on SEAP reporter gene confirmed the augmenting effect of ST7-B on LPS-mediated NF-κB activation in THP1-Blue. Taken together, this is the first study to characterize interactions between Blastocystis spp. and host TLR activation using an in vitro reporter model.

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

    Directory of Open Access Journals (Sweden)

    Kathleen L. McCoy

    2016-01-01

    Full Text Available 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.

  11. Toll-like receptors as modulators of intestinal barrier function

    OpenAIRE

    Estévez Medina, Javier

    2016-01-01

    Las patologías funcionales (síndrome del intestino irritable, IBS) e inflamatorias gastrointestinales (enfermedad inflamatoria intestinal, IBD) se caracterizan por alteraciones de la función barrera epitelial, con un aumento de la permeabilidad, y cambios en la microbiota intestinal. Los receptores de tipo Toll (TLRs) participan en el reconocimiento bacteriano en el intestino y en el control neuroinmune local, estando, por tanto, implicados en la regulación de la función barrera del epitelio ...

  12. Toll-like receptor 4 decoy, TOY, attenuates gram-negative bacterial sepsis.

    Science.gov (United States)

    Jung, Keehoon; Lee, Jung-Eun; Kim, Hak-Zoo; Kim, Ho Min; Park, Beom Seok; Hwang, Seong-Ik; Lee, Jie-Oh; Kim, Sun Chang; Koh, Gou Young

    2009-10-09

    Lipopolysaccharide (LPS), the Gram-negative bacterial outer membrane glycolipid, induces sepsis through its interaction with myeloid differentiation protein-2 (MD-2) and Toll-like receptor 4 (TLR4). To block interaction between LPS/MD-2 complex and TLR4, we designed and generated soluble fusion proteins capable of binding MD-2, dubbed TLR4 decoy receptor (TOY) using 'the Hybrid leucine-rich repeats (LRR) technique'. TOY contains the MD-2 binding ectodomain of TLR4, the LRR motif of hagfish variable lymphocyte receptor (VLR), and the Fc domain of IgG1 to make it soluble, productive, and functional. TOY exhibited strong binding to MD-2, but not to the extracellular matrix (ECM), resulting in a favorable pharmacokinetic profile in vivo. TOY significantly extended the lifespan, when administered in either preventive or therapeutic manners, in both the LPS- and cecal ligation/puncture-induced sepsis models in mice. TOY markedly attenuated LPS-triggered NF-kappaB activation, secretion of proinflammatory cytokines, and thrombus formation in multiple organs. Taken together, the targeting strategy for sequestration of LPS/MD-2 complex using the decoy receptor TOY is effective in treating LPS- and bacteria-induced sepsis; furthermore, the strategy used in TOY development can be applied to the generation of other novel decoy receptor proteins.

  13. Differential expression of toll-like receptors in patients with irritable bowel syndrome.

    LENUS (Irish Health Repository)

    Brint, Elizabeth K

    2011-02-01

    The pathogenesis of irritable bowel syndrome (IBS) is poorly understood. One contributory factor may be low-grade mucosal inflammation, perhaps initiated by the microbiota. Toll-like receptors (TLRs) are a family of pathogen-recognition receptors of the innate immune system. The aim of this study was to evaluate the potential involvement of TLRs in IBS to further understand the involvement of the innate immune system in this complex disorder.

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

    Energy Technology Data Exchange (ETDEWEB)

    Cody, Vivian, E-mail: cody@hwi.buffalo.edu [Hauptman–Woodward Medical Research Institute, 700 Ellicott Street, Buffalo, NY 14203 (United States); University at Buffalo, 700 Ellicott Street, Buffalo, NY 14203 (United States); Pace, Jim [Hauptman–Woodward Medical Research Institute, 700 Ellicott Street, Buffalo, NY 14203 (United States); Nawar, Hesham F.; King-Lyons, Natalie [University at Buffalo, 3435 Main Street, Buffalo, NY 14214 (United States); Liang, Shuang [University of Louisville School of Dentistry, Louisville, KY 40292 (United States); Connell, Terry D. [University at Buffalo, 3435 Main Street, Buffalo, NY 14214 (United States); Hajishengallis, George [University of Pennsylvania School of Dental Medicine, Philadelphia, PA 19104-6030 (United States); Hauptman–Woodward Medical Research Institute, 700 Ellicott Street, Buffalo, NY 14203 (United States)

    2012-12-01

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

  15. Toll Like Receptor-9 Mediated Invasion in Breast Cancer

    Science.gov (United States)

    2012-07-01

    breast cancers because we also recently demon- strated a similar, decreased survival associated with low tumor TLR9 expression in renal cell carcinomas...epithelium in Helicobacter pylori infection . Clin Exp Immunol 136(3):521–526 9. Ilvesaro JM, Merrell MA, Swain TM, Davidson J, Zayzafoon M, Harris KW...KL, Sferruzzi-Perri AN, Thompson JG, Roberts CT (2010) Beyond oxygen: complex regulation and activity of hypoxia inducible factors in pregnancy . Hum

  16. Toll-Like Receptor Expression in the Blood and Brain of Patients and a Mouse Model of Parkinson’s Disease

    Science.gov (United States)

    St-Amour, Isabelle; Saint-Pierre, Martine; Lamontagne-Proulx, Jérôme; Kriz, Jasna; Barker, Roger A.

    2015-01-01

    Background: Accumulating evidence supports a role for the immune system in the pathogenesis of Parkinson’s disease. Importantly, recent preclinical studies are now suggesting a specific contribution of inflammation to the α-synuclein-induced pathology seen in this condition. Methods: We used flow cytometry and western blots to detect toll-like receptor 2 and 4 expression in blood and brain samples of Parkinson’s disease patients and mice overexpressing human α-synuclein. To further assess the effects of α-synuclein overexpression on the innate immune system, we performed a longitudinal study using Thy1.2-α-synuclein mice that expressed a bicistronic DNA construct (reporter genes luciferase and green fluorescent protein) under the transcriptional control of the murine toll-like receptor 2 promoter. Results: Here, we report increases in toll-like receptors 2 and 4 expression in circulating monocytes and of toll-like receptor 4 in B cells and in the caudate/putamen of Parkinson’s disease patients. Monthly bioluminescence imaging of Thy1.2-α-synuclein mice showed increasing toll-like receptor 2 expression from 10 months of age, although no change in toll-like receptor 2 and 4 expression was observed in the blood and brain of these mice at 12 months of age. Dexamethasone treatment starting at 5 months of age for 1 month significantly decreased the microglial response in the brain of these mice and promoted functional recovery as observed using a wheel-running activity test. Conclusion: Our results show that toll-like receptors 2 and 4 are modulated in the blood and brain of Parkinson’s disease patients and that overexpression of α-synuclein leads to a progressive microglial response, the inhibition of which has a beneficial impact on some motor phenotypes of an animal model of α-synucleinopathy. PMID:25522431

  17. Structural relationship of the lipid A acyl groups to activation of murine Toll-like receptor 4 by lipopolysaccharides from pathogenic strains of Burkholderia mallei, Acinetobacter baumannii and Pseudomonas aeruginosa

    Directory of Open Access Journals (Sweden)

    Kirill V Korneev

    2015-11-01

    Full Text Available Toll-like receptor 4 (TLR4 is required for activation of innate immunity upon recognition of lipopolysaccharide (LPS of Gram-negative bacteria. The ability of TLR4 to respond to a particular LPS species is important since insufficient activation may not prevent bacterial growth while excessive immune reaction may lead to immunopathology associated with sepsis. Here we investigated the biological activity of LPS from Burkholderia mallei that causes glanders, and from the two well-known opportunistic pathogens Acinetobacter baumannii and Pseudomonas aeruginosa (causative agents of nosocomial infections. For each bacterial strain, R-form LPS preparations were purified by hydrophobic chromatography and the chemical structure of lipid A, an LPS structural component, was elucidated by HR-MALDI-TOF mass spectrometry. The biological activity of LPS samples was evaluated by their ability to induce production of proinflammatory cytokines, such as IL-6 and TNF, by bone marrow-derived macrophages (BMDM. Our results demonstrate direct correlation between the biological activity of LPS from these pathogenic bacteria and the extent of their lipid A acylation.

  18. Structural Relationship of the Lipid A Acyl Groups to Activation of Murine Toll-Like Receptor 4 by Lipopolysaccharides from Pathogenic Strains of Burkholderia mallei, Acinetobacter baumannii, and Pseudomonas aeruginosa

    Science.gov (United States)

    Korneev, Kirill V.; Arbatsky, Nikolay P.; Molinaro, Antonio; Palmigiano, Angelo; Shaikhutdinova, Rima Z.; Shneider, Mikhail M.; Pier, Gerald B.; Kondakova, Anna N.; Sviriaeva, Ekaterina N.; Sturiale, Luisa; Garozzo, Domenico; Kruglov, Andrey A.; Nedospasov, Sergei A.; Drutskaya, Marina S.; Knirel, Yuriy A.; Kuprash, Dmitry V.

    2015-01-01

    Toll-like receptor 4 (TLR4) is required for activation of innate immunity upon recognition of lipopolysaccharide (LPS) of Gram-negative bacteria. The ability of TLR4 to respond to a particular LPS species is important since insufficient activation may not prevent bacterial growth while excessive immune reaction may lead to immunopathology associated with sepsis. Here, we investigated the biological activity of LPS from Burkholderia mallei that causes glanders, and from the two well-known opportunistic pathogens Acinetobacter baumannii and Pseudomonas aeruginosa (causative agents of nosocomial infections). For each bacterial strain, R-form LPS preparations were purified by hydrophobic chromatography and the chemical structure of lipid A, an LPS structural component, was elucidated by HR-MALDI-TOF mass spectrometry. The biological activity of LPS samples was evaluated by their ability to induce production of proinflammatory cytokines, such as IL-6 and TNF, by bone marrow-derived macrophages. Our results demonstrate direct correlation between the biological activity of LPS from these pathogenic bacteria and the extent of their lipid A acylation. PMID:26635809

  19. Toll-like receptor-2 deficiency enhances non-alcoholic steatohepatitis

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    Brady Kristen

    2010-05-01

    Full Text Available Abstract Background Previously we reported that mice deficient in toll-like receptor 4 (TLR-4 signalling were protected from diet-induced non-alcoholic steatohepatitis (NASH. Another member of the toll-like receptor family, TLR-2, has been shown to play a role in lipid trafficking via uptake of diacylated lipoproteins. However, a role for TLR-2 in NASH has not been elucidated. The objectives of the current study were to examine the influence of dietary fat quality and TLR-2 on NASH pathogenesis. Methods Steatohepatitis was induced in male Db, C57BL/6 and TLR-2-/- mice by feeding an L-amino acid-defined diet that was deficient in methionine and choline (MCDD. Mice fed the base diet supplemented with methionine and choline (control diet; CD were used as controls. To determine the role of fat quality, MCDD was enriched with polyunsaturated corn oil (PUFA or coconut oil that is comprised mostly of saturated fat (SAFA; the total amount of each fat was 112.9 g/kg of diet. After 8 weeks of feeding CD or MCDD, hepatic steatosis, inflammation and necrosis were evaluated in histological sections. Total RNA was extracted from frozen liver samples and mRNA expression of TNFα, collagen α1, IL-10, peroxisome proliferator-activated receptor-γ (PPAR-γ, TLR-4, and CD14, was analyzed via real-time PCR. Protein levels of TLR-2 were analyzed by western blot. Results Panlobular macrovessicular steatosis and diffuse leukocyte infiltration were noted in PUFA-fed Db mice. Histological scores demonstrated significantly less steatosis, inflammation and necrosis in SAFA-fed mice of all mouse strains. However, compared to wild type mice, hepatocellular damage was notably more severe in TLR-2-/- mice. Consistent with histological findings, mRNA expression of TNFα was elevated by approximately 3-fold in TLR-2-/- mice; PPAR-γ expression was blunted in this strain compared to wild type. Expression of the matrix protein collagen αI was also significantly higher in TLR-2

  20. Toll-like receptors and cells migration%Toll样受体与细胞迁移

    Institute of Scientific and Technical Information of China (English)

    苏海英; 莫碧文

    2011-01-01

    The invasion of sensitive pathogens invade the body, and reproductive system encoded pattern recognition receptors recognize pathogens,thus start the innate immune system. Toll-like receptor (TLR) plays an important role in the immune system recognition of microbial pathogens thus is a regulating antigen receptor family. TLR are expressed on many immune and non immune cells while participate in a variety of cell migration, so they are closely related to movement and migration of cells.Activation of TLR induce a series of inflammatory mejiators,including cytokines,chemokines and so on,and result in strong biological effects. The most prominent biological function of TLR is on the one hand,they enhance the synthesis and release of cytokine and chemokine that trigger inflammation and cell effect,on the other hand, they promote the mature of antigen presenting cells that induce the acquired immune response. So TLR are the bridge of innate immunity and acquired immunity.%敏感性侵袭病原体侵入机体,生殖系编码模式识别受体识别病原体,由此启动先天免疫系统.Toll样受体家族(toll-like receptors,TLR)是在免疫系统特异性识别微生物病原体抗原中发挥重要调控作用的受体家族.TLR表达于许多的免疫和非免疫细胞,参与多种细胞迁移,与细胞的迁移性运动密切相关.活化TLR诱导产生一系列的炎症介质包括细胞因子、趋化因子等从而产生强有力的生物学效应.TLR最突出的生物学功能一方面促进细胞因子或趋化因子的合成与释放,引发炎症反应或细胞效应,另一方面是促进抗原递呈细胞的成熟,从而诱导机体的获得性免疫反应,因而是机体介导天然免疫转向获得性免疫的桥梁.

  1. Diversity in the Toll-Like Receptor Genes of the African Penguin (Spheniscus demersus)

    OpenAIRE

    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 increasingl...

  2. Filaria/Wolbachia activation of dendritic cells and development of Th1-associated responses is dependent on Toll-like receptor 2 in a mouse model of ocular onchocerciasis (river blindness).

    Science.gov (United States)

    Daehnel, K; Gillette-Ferguson, I; Hise, A G; Diaconu, E; Harling, M J; Heinzel, F P; Pearlman, E

    2007-09-01

    Toll-like receptors (TLRs) regulate dendritic cell function and activate signals that mediate the nature of the adaptive immune response. The current study examined the role of TLRs in dendritic cell activation and in regulating T cell and antibody responses to antigens from the filarial parasites Onchocerca volvulus and Brugia malayi, which cause river blindness and lymphatic filariasis, respectively. Bone-marrow-derived CD11c(+) cells from C57BL/6 and TLR4(-/-) mice produced high levels of IL-6 and RANTES, and showed elevated surface CD40 expression, whereas CD11c(+) cells from myeloid differentiation factor 88(-/-) (MyD88(-/-)), TLR2(-/-) and TLR2/4(-/-) mice were not activated. Similarly, IFN-gamma production by splenocytes from immunized TLR2(-/-) mice was significantly impaired compared with splenocytes from C57BL/6 and TLR4(-/-) mice. In contrast, there was no difference among these strains in Th2-associated responses including IL-5 production by splenocytes from immunized animals, serum IgE and IgG(1), or eosinophil infiltration into the corneal stroma. Neutrophil recruitment to the cornea and CXC chemokine production was inhibited in immunized TLR2(-/-) mice compared with C57BL/6 and TLR4(-/-) mice. Taken together, these findings demonstrate an essential role for TLR2 in filaria-induced dendritic cell activation, IFN-gamma production and neutrophil migration to the cornea, but does not affect filaria-induced Th2-associated responses.

  3. Toll-like receptor and tumour necrosis factor dependent endotoxin-induced acute lung injury

    Science.gov (United States)

    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

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

    Science.gov (United States)

    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

  5. Molecular and cellular dynamics of the Toll-like receptor 4 pathway.

    Directory of Open Access Journals (Sweden)

    Nick eGay

    2014-10-01

    Full Text Available As well as being the primary signaling receptor for bacterial endotoxin or lipopolysaccharide Toll-like receptor 4 function is modulated by numerous factors not only in the context of microbial pathogenesis but also autoimmune and allergic diseases. TLR4 is subject to multiple levels of endogenous control and regulation from biosynthesis and trafficking to signal transduction and degradation. On the other hand regulation of TLR4 activity breaks down during Gram –ve sepsis leading to systemic damage, multi organ failure and death. In this article we review how TLR4 traffics from the early secretory pathway, the cis/trans Golgi to the cell surface and endolysosomal compartments. We will present evidence about how these processes influence signaling and can potentially lead to ligand independent constitutive activation that may contribute to pathogenesis in sepsis. We will also discuss how sustained signaling may be coupled to endocytosis and consider the potential molecular mechanisms of immuno-modulators that modify TLR4 signalling function including the cat allergen FelD1 and endogenous protein ligands such as the extracellular matrix protein tenascin C and calprotectin (MRP8/14.

  6. Interplay of the Gastric Pathogen Helicobacter pylori with Toll-Like Receptors

    Directory of Open Access Journals (Sweden)

    Suneesh Kumar Pachathundikandi

    2015-01-01

    Full Text Available Toll-like receptors (TLRs are crucial for pathogen recognition and downstream signaling to induce effective immunity. The gastric pathogen Helicobacter pylori is a paradigm of persistent bacterial infections and chronic inflammation in humans. The chronicity of inflammation during H. pylori infection is related to the manipulation of regulatory cytokines. In general, the early detection of H. pylori by TLRs and other pattern recognition receptors (PRRs is believed to induce a regulatory cytokine or chemokine profile that eventually blocks the resolution of inflammation. H. pylori factors such as LPS, HSP-60, NapA, DNA, and RNA are reported in various studies to be recognized by specific TLRs. However, H. pylori flagellin evades the recognition of TLR5 by possessing a conserved N-terminal motif. Activation of TLRs and resulting signal transduction events lead to the production of pro- and anti-inflammatory mediators through activation of NF-κB, MAP kinases, and IRF signaling pathways. The genetic polymorphisms of these important PRRs are also implicated in the varied outcome and disease progression. Hence, the interplay of TLRs and bacterial factors highlight the complexity of innate immune recognition and immune evasion as well as regulated processes in the progression of associated pathologies. Here we will review this important aspect of H. pylori infection.

  7. Toll-like receptors (TLRs) in aquatic animals: signaling pathways, expressions and immune responses.

    Science.gov (United States)

    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.

  8. DMPD: Toll-like receptors: from the discovery of NFkappaB to new insights intotranscriptional regulations in innate immunity. [Dynamic Macrophage Pathway CSML Database

    Lifescience Database Archive (English)

    Full Text Available 16930560 Toll-like receptors: from the discovery of NFkappaB to new insights intotr...2-13. Epub 2006 Aug 22. (.png) (.svg) (.html) (.csml) Show Toll-like receptors: from the discovery of NFkapp...6930560 Title Toll-like receptors: from the discovery of NFkappaB to new insights intotranscriptional regula

  9. DMPD: Toll-like receptors, RIG-I-like RNA helicases and the antiviral innate immuneresponse. [Dynamic Macrophage Pathway CSML Database

    Lifescience Database Archive (English)

    Full Text Available 17667934 Toll-like receptors, RIG-I-like RNA helicases and the antiviral innate imm...g) (.svg) (.html) (.csml) Show Toll-like receptors, RIG-I-like RNA helicases and the antiviral innate immune...response. PubmedID 17667934 Title Toll-like receptors, RIG-I-like RNA helicases and the anti

  10. DMPD: TICAM-1 and TICAM-2: toll-like receptor adapters that participate in inductionof type 1 interferons. [Dynamic Macrophage Pathway CSML Database

    Lifescience Database Archive (English)

    Full Text Available 15618008 TICAM-1 and TICAM-2: toll-like receptor adapters that participate in induc... Mar;37(3):524-9. (.png) (.svg) (.html) (.csml) Show TICAM-1 and TICAM-2: toll-like receptor adapters that part... TICAM-2: toll-like receptor adapters that participate in inductionof type 1 interferons. Authors Seya T, Os

  11. Schisandrin B exerts anti-neuroinflammatory activity by inhibiting the Toll-like receptor 4-dependent MyD88/IKK/NF-κB signaling pathway in lipopolysaccharide-induced microglia.

    Science.gov (United States)

    Zeng, Ke-Wu; Zhang, Tai; Fu, Hong; Liu, Geng-Xin; Wang, Xue-Mei

    2012-10-05

    Microglial-mediated neuroinflammation is now considered to be central to the pathogenesis of various neurodegenerative processes, including Alzheimer's disease and Parkinson's disease. Therefore, rational modulation of microglia function to obtain neuroprotective effects is important for the development of safe and effective anti-inflammatory and neuroprotective agents. Here, we investigated the anti-inflammatory and neuroprotective effects, and potential molecular mechanism of action of Schisandrin B (Sch B); which is isolated from the Schizandra fruit (Schisandra chinesnesis). Sch B exerted significant neuroprotective effects against microglial-mediated inflammatory injury in microglia-neuron co-cultures. In addition, Sch B significantly downregulated pro-inflammatory cytokines, including nitrite oxide (NO), tumor necrosis factor (TNF)-α, prostaglandin E(2) (PGE(2)), interleukin (IL)-1β and IL-6. Additionally, Sch B inhibited the interaction of Toll-like receptor 4 with the Toll adapter proteins MyD88, IRAK-1 and TRAF-6 resulting in an inhibition of the IKK/nuclear transcription factor (NF)-κB inflammatory signaling pathway. Furthermore, Sch B inhibited the production of reactive oxygen species (ROS) and NADPH oxidase activity in microglia. In summary, Sch B may exert neuroprotective activity by attenuating the microglial-mediated neuroinflammatory response by inhibiting the TLR4-dependent MyD88/IKK/NF-κB signaling pathway.

  12. A new Vitreoscilla filiformis extract grown on spa water-enriched medium activates endogenous cutaneous antioxidant and antimicrobial defenses through a potential Toll-like receptor 2/protein kinase C, zeta transduction pathway

    Directory of Open Access Journals (Sweden)

    Mahe YF

    2013-08-01

    Full Text Available Yann F Mahe,1 Marie-Jesus Perez,1 Charlotte Tacheau,1 Chantal Fanchon,2 Richard Martin,3 Françoise Rousset,1 Sophie Seite4 1L’Oreal Research and Innovation, Clichy, 2L’Oréal Research and Innovation, Chevilly Larue, 3L’Oréal Research and Innovation Tours, 4La Roche-Posay Pharmaceutical Laboratories, Asnières, France Abstract: Vitreoscilla filiformis (VF biomass (VFB has been widely used in cosmetic preparations and shown to modulate the major inducible free-radical scavenger mitochondrial superoxide dismutase in skin cells. By adding La Roche-Posay (LRP thermal spring water to the VF culture medium, we obtained a biomass (LRP-VFB with a similar mitochondrial superoxide dismutase activation capacity to VF. Also, the new biomass more powerfully stimulated mRNA expression and antimicrobial peptides in reconstructed epidermis. Interestingly, a predictive computer model that analyzed transducing events within skin epidermal cells suggested that this protective activity may involve the Toll-like receptor 2/protein kinase C, zeta transduction pathway. Protein kinase C, zeta inhibition was effectively shown to abolish VFB-induced gene stimulation and confirmed this hypothesis. This thus opens new avenues for investigation into the improvement of skin homeostatic defense in relation to the control of its physiological microbiota and innate immunity. Keywords: innate skin defenses, TLR2, PKCz, La Roche-Posay, mitochondrial superoxide dismutase, SOD2

  13. Cervical Cancer Cell Supernatants Induce a Phenotypic Switch from U937-Derived Macrophage-Activated M1 State into M2-Like Suppressor Phenotype with Change in Toll-Like Receptor Profile

    Science.gov (United States)

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

    2014-01-01

    Cervical cancer (CC) is the second most common cancer among women worldwide. Infection with human papillomavirus (HPV) is the main risk factor for developing CC. Macrophages are important immune effector cells; they can be differentiated into two phenotypes, identified as M1 (classically activated) and M2 (alternatively activated). Macrophage polarization exerts profound effects on the Toll-like receptor (TLR) profile. In this study, we evaluated whether the supernatant of human CC cells HeLa, SiHa, and C-33A induces a shift of M1 macrophage toward M2 macrophage in U937-derived macrophages. Results. The results showed that soluble factors secreted by CC cells induce a change in the immunophenotype of macrophages from macrophage M1 into macrophage M2. U937-derived macrophages M1 released proinflammatory cytokines and nitric oxide; however, when these cells were treated with the supernatant of CC cell lines, we observed a turnover of M1 toward M2. These cells increased CD163 and IL-10 expression. The expression of TLR-3, -7, and -9 is increased when the macrophages were treated with the supernatant of CC cells. Conclusions. Our result strongly suggests that CC cells may, through the secretion of soluble factors, induce a change of immunophenotype M1 into M2 macrophages. PMID:25309919

  14. Cervical Cancer Cell Supernatants Induce a Phenotypic Switch from U937-Derived Macrophage-Activated M1 State into M2-Like Suppressor Phenotype with Change in Toll-Like Receptor Profile

    Directory of Open Access Journals (Sweden)

    Karina Sánchez-Reyes

    2014-01-01

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

  15. RNA Interference of Interferon Regulatory Factor-1 Gene Expression in THP-1 Cell Line Leads to Toll-Like Receptor-4 Overexpression/Activation As Well As Up-modulation of Annexin-II

    Directory of Open Access Journals (Sweden)

    Christos I. Maratheftis

    2007-12-01

    Full Text Available Interferon regulatory factor-1 (IRF-1 is a candidate transcription factor for the regulation of the Toll-like receptor-4 (TLR-4 gene. Using a small interfering RNAbased (siRNA process to silence IRF-1 gene expression in the leukemic monocytic cell line THP-1, we investigated whether such a modulation would alter TLR-4 expression and activation status in these cells. The siIRF-1 cells expressed elevated levels of TLR-4 mRNA and protein compared to controls by 90% and 77%, respectively. ICAM.1 protein expression and apoptosis levels were increased by 8.35- and 4.25-fold, respectively. The siIRF-1 cells overexpressed Bax mRNA compared to controls. Proteomic analysis revealed upmodulation of the Annexin-II protein in siIRF-1 THP-1 cells. Myelodysplastic syndrome (MDS patients with an absence of full-length IRF-1 mRNA also overexpressed Annexin-II. It is plausible that this overexpression may lead to the activation of TLR-4 contributing to the increased apoptosis characterizing MDS.

  16. Toll-like receptor 4 mediates the antitumor host response induced by Ganoderma atrum polysaccharide.

    Science.gov (United States)

    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.

  17. Role of Toll-like receptors in health and diseases of gastrointestinal tract

    Institute of Scientific and Technical Information of China (English)

    Greg Harris; Rhonda KuoLee; Wangxue Chen

    2006-01-01

    The human gastrointestinal (GI) tract is colonized by non-pathogenic commensal microflora and frequently exposed to many pathogenic organisms.For the maintenance of GI homeostasis, the host must discriminate between pathogenic and non-pathogenic organisms and initiate effective and appropriate immune and inflammatory responses. Mammalian toll-like receptors (TLRs) are members of the pattern-recognition receptor (PRR) family that plays a central role in the initiation of innate cellular immune responses and the subsequent adaptive immune responses to microbial pathogens. Recent studies have shown that gastrointestinal epithelial cells express almost all TLR subtypes characterized to date and that the expression and activation of TLRs in the GI tract are tightly and coordinately regulated. This review summarizes the current understanding of the crucial dual roles of TLRs in the development of host innate and adaptive immune responses to GI infections and the maintenance of the immune tolerance to commensal bacteria through down-regulation of surface expression of TLRs in intestinal epithelial cells.

  18. Inflammatory Role of Toll-Like Receptors in Human and Murine Adipose Tissue

    Directory of Open Access Journals (Sweden)

    Odile Poulain-Godefroy

    2010-01-01

    Full Text Available It was recently demonstrated that TLR4 activation via dietary lipids triggers inflammatory pathway and alters insulin responsiveness in the fat tissue during obesity. Here, we question whether other TLR family members could participate in the TLR-mediated inflammatory processes occurring in the obese adipose tissue. We thus studied the expression of TLR1, TLR2, TLR4, and TLR6 in adipose tissue. These receptors are expressed in omental and subcutaneous human fat tissue, the expression being higher in the omental tissue, independently of the metabolic status of the subject. We demonstrated a correlation of TLRs expression within and between each depot suggesting a coregulation. Murine 3T3-L1 preadipocyte cells stimulated with Pam3CSK4 induced the expression of some proinflammatory markers. Therefore, beside TLR4, other toll-like receptors are differentially expressed in human fat tissue, and functional in an adipocyte cell line, suggesting that they might participate omental adipose tissue-related inflammation that occurs in obesity.

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

    Institute of Scientific and Technical Information of China (English)

    Sinéad; M; Smith

    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 inflamma-tory cells to the gastric mucosa. Pathogen recognition receptors of the toll-like receptor(TLR) family mediate many of these cell signalling events. This review dis-cusses 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 iden-tification of host mediators of H. pylori-induced patho-genesis 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.

  20. Emerging role of Toll-like receptors in the control of pain and itch

    Institute of Scientific and Technical Information of China (English)

    Tong Liu; Yong-Jing Gao; Ru-Rong Ji

    2012-01-01

    Toll-like receptors (TLRs) are germline-encoded pattern-recognition receptors that initiate innate immune responses by recognizing molecular structures shared by a wide range of pathogens,known as pathogen-associated molecular patterns (PAMPs).After tissue injury or cellular stress,TLRs also detect endogenous ligands known as danger-associated molecular patterns (DAMPs).TLRs are expressed in both non-neuronal and neuronal cell types in the central nervous system (CNS) and contribute to both infectious and non-infectious disorders in the CNS.Following tissue insult and nerve injury,TLRs (such as TLR2,TLR3,and TLR4) induce the activation of microglia and astrocytes and the production of the proinflammatory cytokines in the spinal cord,leading to the development and maintenance of inflammatory pain and neuropathic pain.In particular,primary sensory neurons,such as nociceptors,express TLRs (e.g.,TLR4 and TLR7) to sense exogenous PAMPs and endogenous DAMPs released after tissue injury and cellular stress.These neuronal TLRs are new players in the processing of pain and itch by increasing the excitability of primary sensory neurons.Given the prevalence of chronic pain and itch and the suffering of affected people,insights into TLR signaling in the nervous system will open a new avenue for the management of clinical pain and itch.

  1. A comparative review of Toll-like receptor 4 expression and functionality in different animal species

    Directory of Open Access Journals (Sweden)

    Céline eVAURE

    2014-07-01

    Full Text Available Toll-like receptors (TLRs belong to the pattern recognition receptor (PRR family, a key component of the innate immune system. TLRs detect invading pathogens and initiate an immediate immune response to them, followed by a long-lasting adaptive immune response. Activation of TLRs leads to the synthesis of pro-inflammatory cytokines and chemokines and the expression of co-stimulatory molecules. TLR4 specifically recognizes bacterial lipopolysaccharide (LPS, along with several other components of pathogens and endogenous molecules produced during abnormal situations, such as tissue damage. Evolution across species can lead to substantial diversity in the TLR4’s affinity and specificity to its ligands, the TLR4 gene and cellular expression patterns and tissue distribution. Consequently, TLR4 functions vary across different species. In recent years, the use of synthetic TLR agonists as adjuvants has emerged as a realistic therapeutic goal, notably for the development of vaccines against poorly immunogenic targets. Given that an adjuvanted vaccine must be assessed in pre-clinical animal models before being tested in humans, the extent to which an animal model represents and predicts the human condition is of particular importance. This review focuses on the current knowledge on the critical points of divergence between human and the mammalian species commonly used in vaccine research and development (non-human primate, mouse, rat, rabbit, swine and dog, in terms of molecular, cellular and functional properties of TLR4.

  2. Toll-like receptor polymorphisms, inflammatory and infectious diseases, allergies, and cancer.

    Science.gov (United States)

    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.

  3. Maternal endotoxin-induced fetal growth restriction in rats: Fetal responses in toll-like receptor

    Directory of Open Access Journals (Sweden)

    Banun Kusumawardani

    2012-09-01

    Full Text Available Background: Porphyromonas gingivalis as a major etiology of periodontal disease can produce virulence factor, lipopolysaccharide/LPS, which is expected to play a role in the intrauterine fetal growth. Trophoblast at the maternal-fetal interface actively participates in response to infection through the expression of a family of natural immune receptors, toll-like receptor (TLR. Purpose: the aims of study were to identify endotoxin concentration in maternal blood serum of Porphyromonas gingivalis-infected pregnant rats, to characterize the TLR-4 expression in trophoblast cells, and to determine its effect on fetal growth. Methods: Female rats were infected with live-Porphyromonas gingivalis at concentration of 2 x 109 cells/ml into subgingival sulcus area of the maxillary first molar before and/or during pregnancy. They were sacrified on 14th and 20th gestational day. Fetuses were evaluated for weight and length. Endotoxin was detected by limulus amebocyte lysate assay in the maternal blood serum. The TLR-4 expression in trophoblast cells was detected by immunohistochemistry. Elevated Toll-Like Receptor-Induced CXCL8 Secretion in Human Blood Basophils from Allergic Donors Is Independent of Toll-Like Receptor Expression Levels.

    Directory of Open Access Journals (Sweden)

    Markus Steiner

    Full Text Available Human blood basophils have recently gained interest in addition to their function as allergic effector cells. Previous work suggests the involvement of innate immune mechanisms in the development and exacerbation of allergic responses, which might be mediated by basophils. We assayed the expression levels of Toll-like receptor (TLR 1, 2, 4 and 6 on purified basophils from birch pollen-, house dust mite-, and non-allergic individuals. Additionally, we compared cytokine and chemokine secretion upon TLR stimulation in these basophil donor groups. Expression of TLR4 on the basophils of the allergic donor groups was decreased and CXCL8 secretion was elevated upon stimulation of TLR1/2 and TLR2/6 compared to the non-allergic donors. Decreased TLR expression and elevated CXCL8 secretion may represent possible mechanisms for aggravation of allergic symptoms in case of parasitic infection.

  4. Predicting novel features of toll-like receptor 3 signaling in macrophages.

    Directory of Open Access Journals (Sweden)

    Mohamed Helmy

    Full Text Available The Toll-like receptor (TLR 3 plays a critical role in mammalian innate immune response against viral attacks by recognizing double-stranded RNA (dsRNA or its synthetic analog polyinosinic-polycytidylic acid (poly (IratioC. This leads to the activation of MAP kinases and NF-kappaB which results in the induction of type I interferons and proinflammatory cytokines to combat the viral infection. To understand the complex interplay of the various intracellular signaling molecules in the regulation of NF-kappaB and MAP kinases, we developed a computational TLR3 model based upon perturbation-response approach. We curated literature and databases to determine the TLR3 signaling topology specifically for murine macrophages. For initial model creation, we used wildtype temporal activation profiles of MAP kinases and NF-kappaB and, for model testing, used TRAF6 KO and TRADD KO data. From dynamic simulations we predict i the existence of missing intermediary steps between extracellular poly (IratioC stimulation and intracellular TLR3 binding, and ii the presence of a novel pathway which is essential for JNK and p38, but not NF-kappaB, activation. Our work shows activation dynamics of signaling molecules can be used in conjunction with perturbation-response models to decipher novel signaling features of complicated immune pathways.

  5. Berberine reduces Toll-like receptor-mediated macrophage migration by suppression of Src enhancement.

    Science.gov (United States)

    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.

  6. [Nle4, D-Phe7]-α-MSH Inhibits Toll-Like Receptor (TLR)2- and TLR4-Induced Microglial Activation and Promotes a M2-Like Phenotype

    Science.gov (United States)

    Carniglia, Lila; Ramírez, Delia; Durand, Daniela; Saba, Julieta; Caruso, Carla; Lasaga, Mercedes

    2016-01-01

    α-melanocyte stimulating hormone (α-MSH) is an anti-inflammatory peptide, proved to be beneficial in many neuroinflammatory disorders acting through melanocortin receptor 4 (MC4R). We previously determined that rat microglial cells express MC4R and that NDP-MSH, an analog of α-MSH, induces PPAR-γ expression and IL-10 release in these cells. Given the great importance of modulation of glial activation in neuroinflammatory disorders, we tested the ability of NDP-MSH to shape microglial phenotype and to modulate Toll-like receptor (TLR)-mediated inflammatory responses. Primary rat cultured microglia were stimulated with NDP-MSH followed by the TLR2 agonist Pam3CSK4 or the TLR4 agonist LPS. NDP-MSH alone induced expression of the M2a/M2c marker Ag1 and reduced expression of the M2b marker Il-4rα and of the LPS receptor Tlr4. Nuclear translocation of NF-κB subunits p65 and c-Rel was induced by LPS and these effects were partially prevented by NDP-MSH. NDP-MSH reduced LPS- and Pam3CSK4-induced TNF-α release but did not affect TLR-induced IL-10 release. Also, NDP-MSH inhibited TLR2-induced HMGB1 translocation from nucleus to cytoplasm and TLR2-induced phagocytic activity. Our data show that NDP-MSH inhibits TLR2- and TLR4-mediated proinflammatory mechanisms and promotes microglial M2-like polarization, supporting melanocortins as useful tools for shaping microglial activation towards an alternative immunomodulatory phenotype. PMID:27359332

  7. Nfkb1 activation by the E26 transformation-specific transcription factors PU.1 and Spi-B promotes Toll-like receptor-mediated splenic B cell proliferation.

    Science.gov (United States)

    Li, Stephen K H; Abbas, Ali K; Solomon, Lauren A; Groux, Gaëlle M N; DeKoter, Rodney P

    2015-05-01

    Generation of antibodies against T-independent and T-dependent antigens requires Toll-like receptor (TLR) engagement on B cells for efficient responses. However, the regulation of TLR expression and responses in B cells is not well understood. PU.1 and Spi-B (encoded by Sfpi1 and Spib, respectively) are transcription factors of the E26 transformation-specific (ETS) family and are important for B cell development and function. It was found that B cells from mice knocked out for Spi-B and heterozygous for PU.1 (Sfpi1(+/-) Spib(-/-) [PUB] mice) proliferated poorly in response to TLR ligands compared to wild-type (WT) B cells. The NF-κB family member p50 (encoded by Nfkb1) is required for lipopolysaccharide (LPS) responsiveness in mice. PUB B cells expressed reduced Nfkb1 mRNA transcripts and p50 protein. The Nfkb1 promoter was regulated directly by PU.1 and Spi-B, as shown by reporter assays and chromatin immunoprecipitation analysis. Occupancy of the Nfkb1 promoter by PU.1 was reduced in PUB B cells compared to that in WT B cells. Finally, infection of PUB B cells with a retroviral vector encoding p50 substantially restored proliferation in response to LPS. We conclude that Nfkb1 transcriptional activation by PU.1 and Spi-B promotes TLR-mediated B cell proliferation.

  8. H1 antihistamines in allergic rhinitis: The molecular pathways of interleukin and toll - like receptor systems

    Directory of Open Access Journals (Sweden)

    Jonny Karunia Fajar

    2016-03-01

    Full Text Available The complex interaction between inflammatory mediators in allergic rhinitis (AR is determined by the role of genetic polymorphisms, including interleukin (IL and toll-like receptor (TLR genes. This study aimed to discuss the effects of H1-antihistamines on IL and TLR systems. Several ILs involved in AR pathogenesis are: IL-4 (rs2243250, rs1800925, rs1801275, rs2227284, rs2070874, IL-6 (rs1800795, rs1800797, IL-10 (rs1800871, rs1800872, IL-12R (rs438421, IL-13 (rs1800925, rs20541, IL-17 (rs3819024, IL-18 (rs360721, rs360718, rs360717, rs187238, IL-23R (rs7517847, and IL-27 (rs153109, rs17855750. In the IL system, histamines stimulate the IL production in Type 2 helper T (Th2 cells through protein kinase A (PKA, janus kinase-signal transducer and activator of transcription (JAK-STAT pathway, and the activation of H1-histamine receptor and histidine decarboxylase (HDC genes. On contrary, antihistamines down-regulate the H1-histamine receptor gene expression through the transcription suppression of HDC and IL genes and suppress histamine basal signaling through the inverse agonistic activity. TLRs involved in AR pathogenesis are TLR2 (rs4696480, rs3804099, rs5743708, TLR4 (rs4986790, TLR6 (rs2381289, TLR7 (rs179008, rs5935438, TRL8 (rs2407992, rs5741883, rs17256081, rs4830805, rs3788935, rs178998, and TLR10 (rs11466651. In the TLR system, histamines trigger the TLR expression by stimulating interferon-γ (IFN-γ to up-regulate mast cells and by stimulating receptor-interacting protein (RIP to activate IκB kinase-β. Contrastingly, antihistamines suppress TIR-domain-containing adaptor protein inducing IFN-β (TRIF and RIP protein and thus inhibit the expression of TLR. In addition, several studies indicated that H1-antihistamines inhibit the IL and TLR systems indirectly.

  9. Toll-like receptor 2 senses hepatitis C virus core protein but not infectious viral particles

    Science.gov (United States)

    Hoffmann, Marco; Zeisel, Mirjam B.; Jilg, Nikolaus; Paranhos-Baccalà, Glaucia; Stoll-Keller, Françoise; Wakita, Takaji; Hafkemeyer, Peter; Blum, Hubert E.; Barth, Heidi; Henneke, Philipp; Baumert, Thomas F.

    2009-01-01

    Toll-like receptors (TLRs) are pathogen recognition molecules activating the innate immune system. Cell surface expressed TLRs, such as TLR2 and TLR4 have been shown to play an important role in human host defenses against viruses through sensing of viral structural proteins. In this study, we aimed to elucidate whether TLR2 and TLR4 participate in inducing antiviral immunity against hepatitis C virus by sensing viral structural proteins. We studied TLR2 and TLR4 activation by cell-culture derived infectious virions (HCVcc) and serum-derived virions in comparison to purified recombinant HCV structural proteins and enveloped virus-like particles. Incubation of TLR2 or TLR4 transfected cell lines with recombinant core protein resulted in activation of TLR2-dependent signaling. In contrast, neither infectious virions nor enveloped HCV-like particles triggered TLR2 and TLR4 signaling. These findings suggest that monomeric HCV core protein but not intact infectious particles are sensed by TLR2. Impairment of core-TLR interaction in infectious viral particles may contribute to escape from innate antiviral immune responses. PMID:20375602

  10. Toll-like receptor 7 affects the pathogenesis of non-alcoholic fatty liver disease

    Science.gov (United States)

    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

  11. Candida albicans phospholipomannan triggers inflammatory responses of human keratinocytes through Toll-like receptor 2.

    Science.gov (United States)

    Li, Min; Chen, Qing; Shen, Yongnian; Liu, Weida

    2009-07-01

    The Toll-like receptors (TLRs) play an important role in the recognition of Candida albicans components and activation of innate immunity. Phospholipomannan (PLM), a glycolipid, is expressed at the surface of C. albicans cell wall, which acts as a member of the pathogen-associated molecular patterns family. In this study, we sought to clarify whether C. albicans-native PLM could induce an inflammation response in human keratinocytes and to determine the underlying mechanisms. Exposure of cultured human primary keratinocytes to PLM led to the increased gene expression and secretion of proinflammatory cytokines (IL-6) and chemokines (IL-8). PLM hydrolysed with beta-d-mannoside mannohydrolase failed to induce gene expression and secretion of IL-6 and IL-8. PLM up-regulated the mRNA and protein levels of TLR2, whereas the mRNA level of TLR4 was not altered. Keratinocytes challenged with PLM resulted in the activation of NF-kappaB and mitogen-activated protein kinase (MAPKs) including p38. Anti-TLR2 neutralizing antibody, NFkappaB and p38MAPK inhibitors blocked the PLM-induced secretion of IL-6, IL-8 in keratinocytes, but no such effect was observed in pretreatment with anti-TLR4-neutralizing antibody and lipopolysaccharide inhibitor (polymyxin B). These data suggest C. albicans-native PLM may contribute to the inflammatory responses of cutaneous candidiasis in the TLR2-NF-kappaB and p38MAPK signalling pathway dependent manner.

  12. Toll-like receptor 7 affects the pathogenesis of non-alcoholic fatty liver disease.

    Science.gov (United States)

    Kim, Sokho; Park, Surim; Kim, Bumseok; Kwon, Jungkee

    2016-06-09

    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.

  13. Toll-like receptor 4 activation promotes cardiac arrhythmias by decreasing the transient outward potassium current (Ito) through an IRF3-dependent and MyD88-independent pathway.

    Science.gov (United States)

    Monnerat-Cahli, Gustavo; Alonso, Hiart; Gallego, Monica; Alarcón, Micaela Lopez; Bassani, Rosana A; Casis, Oscar; Medei, Emiliano

    2014-11-01

    Cardiac arrhythmias are one of the main causes of death worldwide. Several studies have shown that inflammation plays a key role in different cardiac diseases and Toll-like receptors (TLRs) seem to be involved in cardiac complications. In the present study, we investigated whether the activation of TLR4 induces cardiac electrical remodeling and arrhythmias, and the signaling pathway involved in these effects. Membrane potential was recorded in Wistar rat ventricle. Ca(2+) transients, as well as the L-type Ca(2+) current (ICaL) and the transient outward K(+) current (Ito), were recorded in isolated myocytes after 24 h exposure to the TLR4 agonist, lipopolysaccharide (LPS, 1 μg/ml). TLR4 stimulation in vitro promoted a cardiac electrical remodeling that leads to action potential prolongation associated with arrhythmic events, such as delayed afterdepolarization and triggered activity. After 24 h LPS incubation, Ito amplitude, as well as Kv4.3 and KChIP2 mRNA levels were reduced. The Ito decrease by LPS was prevented by inhibition of interferon regulatory factor 3 (IRF3), but not by inhibition of interleukin-1 receptor-associated kinase 4 (IRAK4) or nuclear factor kappa B (NF-κB). Extrasystolic activity was present in 25% of the cells, but apart from that, Ca(2+) transients and ICaL were not affected by LPS; however, Na(+)/Ca(2+) exchanger (NCX) activity was apparently increased. We conclude that TLR4 activation decreased Ito, which increased AP duration via a MyD88-independent, IRF3-dependent pathway. The longer action potential, associated with enhanced Ca(2+) efflux via NCX, could explain the presence of arrhythmias in the LPS group.

  14. 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.

    Science.gov (United States)

    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.

  15. Dynamic evolution of toll-like receptor multigene families in echinoderms.

    Science.gov (United States)

    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

  16. Multiplex screening of 22 single-nucleotide polymorphisms in 7 Toll-like receptors: an association study in rheumatoid arthritis

    DEFF Research Database (Denmark)

    Enevold, Christian; Radstake, Timothy R D; Coenen, Marieke J H

    2010-01-01

    Toll-like receptors (TLR) have been implicated in the pathogenesis of arthritis. We investigated the role of functional variants of TLR in the disease phenotype and severity of rheumatoid arthritis (RA)....

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

    Science.gov (United States)

    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.

  18. Cytokine production by human odontoblast-like cells upon Toll-like receptor-2 engagement.

    Science.gov (United States)

    Farges, Jean-Christophe; Carrouel, Florence; Keller, Jean-François; Baudouin, Caroline; Msika, Philippe; Bleicher, Françoise; Staquet, Marie-Jeanne

    2011-04-01

    Recent studies have suggested that odontoblasts are involved in the dental pulp immune response to oral pathogens that invade human dentin during the caries process. How odontoblasts regulate the early inflammatory and immune pulp response to Gram-positive bacteria, which predominate in shallow and moderate dentin caries, is still poorly understood. In this study, we investigated the production of pro- and anti-inflammatory cytokines by odontoblast-like cells upon engagement of Toll-like receptor (TLR) 2, a pattern recognition molecule activated by Gram-positive bacteria components. We used a highly sensitive Milliplex(®) kit for detecting cytokines released by cells stimulated with lipoteichoic acid (LTA), a cell wall component of Gram-positive bacteria, or with the potent TLR2 synthetic agonist Pam2CSK4. We found that odontoblasts produce the pro-inflammatory cytokines interleukin (IL)-6 and CXCL8, as well as the immunosuppressive cytokine IL-10 in response to TLR2 agonists. GM-CSF, IFNγ, IL-1β, IL-2, IL-4, IL-5, IL-7, IL-12(p70), IL-13 and TNF-α were not detected. These data indicate that TLR2 activation in human odontoblasts selectively induces production of mediators known to influence positively or negatively inflammatory and immune responses in pathogen-challenged tissues. We suggest that these molecules might be important in regulating the fine tuning of the pulp response to Gram-positive bacteria which enter dentin during the caries process.

  19. The emerging role of toll-like receptor pathways in surgical diseases.

    LENUS (Irish Health Repository)

    Romics, Laszlo Jr

    2012-02-03

    OBJECTIVE: To outline the emerging significance of Toll-like receptor (TLR) signaling pathways in surgical diseases. DATA SOURCES: A systematic review of the literature was undertaken by searching the MEDLINE database for the period 1966 to 2005 without language restriction. STUDY SELECTION: Original or review articles that described experimental data on the activation of TLR signaling pathways in surgically relevant diseases were selected for inclusion in this review. DATA EXTRACTION: Data were obtained from peer-reviewed articles and references. DATA SYNTHESIS: The role of TLRs in the recognition of pathogens renders them a key figure in the activation of both innate and adaptive immune responses during sepsis. However, emerging evidence points to fundamentally important roles in ulcerative colitis, Crohn disease, and Helicobacter pylori infection in the gastrointestinal tract and in the development of atherosclerotic plaques in the cardiovascular system. Furthermore, recent studies suggest that the regulation of the TLR pathway fulfills a central role in anticancer immunotherapy and in organ rejection after transplantation. CONCLUSION: Given the clinical significance of TLR pathways, the targeting of individual molecular components is likely to offer a broad range of future therapeutic modalities.

  1. Gene expression induced by Toll-like receptors in macrophages requires the transcription factor NFAT5.

    Science.gov (United States)

    Buxadé, Maria; Lunazzi, Giulia; Minguillón, Jordi; Iborra, Salvador; Berga-Bolaños, Rosa; Del Val, Margarita; Aramburu, José; López-Rodríguez, Cristina

    2012-02-13

    Toll-like receptors (TLRs) engage networks of transcriptional regulators to induce genes essential for antimicrobial immunity. We report that NFAT5, previously characterized as an osmostress responsive factor, regulates the expression of multiple TLR-induced genes in macrophages independently of osmotic stress. NFAT5 was essential for the induction of the key antimicrobial gene Nos2 (inducible nitric oxide synthase [iNOS]) in response to low and high doses of TLR agonists but is required for Tnf and Il6 mainly under mild stimulatory conditions, indicating that NFAT5 could regulate specific gene patterns depending on pathogen burden intensity. NFAT5 exhibited two modes of association with target genes, as it was constitutively bound to Tnf and other genes regardless of TLR stimulation, whereas its recruitment to Nos2 or Il6 required TLR activation. Further analysis revealed that TLR-induced recruitment of NFAT5 to Nos2 was dependent on inhibitor of κB kinase (IKK) β activity and de novo protein synthesis, and was sensitive to histone deacetylases. In vivo, NFAT5 was necessary for effective immunity against Leishmania major, a parasite whose clearance requires TLRs and iNOS expression in macrophages. These findings identify NFAT5 as a novel regulator of mammalian anti-pathogen responses.

  2. The herpes simplex virus 1-encoded envelope glycoprotein B activates NF-κB through the Toll-like receptor 2 and MyD88/TRAF6-dependent signaling pathway.

    Directory of Open Access Journals (Sweden)

    Mingsheng Cai

    Full Text Available The innate immune response plays a critical role in the host defense against invading pathogens, and TLR2, a member of the Toll-like receptor (TLR family, has been implicated in the immune response and initiation of inflammatory cytokine secretion against several human viruses. Previous studies have demonstrated that infectious and ultraviolet-inactivated herpes simplex virus 1 (HSV-1 virions lead to the activation of nuclear factor kappa B (NF-κB and secretion of proinflammatory cytokines via TLR2. However, except for the envelope glycoprotein gH and gL, whether there are other determinants of HSV-1 responsible for TLR2 mediated biological effects is not known yet. Here, we demonstrated that the HSV-1-encoded envelope glycoprotein gB displays as molecular target recognized by TLR2. gB coimmunoprecipitated with TLR2, TLR1 and TLR6 in transfected and infected human embryonic kidney (HEK 293T cells. Treatment of TLR2-transfected HEK293T (HEK293T-TLR2 cells with purified gB results in the activation of NF-κB reporter, and this activation requires the recruitment of the adaptor molecules myeloid differentiation primary-response protein 88 (MyD88 and tumor necrosis factor receptor-associated factor 6 (TRAF6 but not CD14. Furthermore, activation of NF-κB was abrogated by anti-gB and anti-TLR2 blocking antibodies. In addition, the expression of interleukin-8 induced by gB was abrogated by the treatment of the human monocytic cell line THP-1 with anti-TLR2 blocking antibody or by the incubation of gB with anti-gB antibody. Taken together, these results indicate the importance and potency of HSV-1 gB as one of pathogen-associated molecular patterns (PAMPs molecule recognized by TLR2 with immediate kinetics.

  3. Myxoma virus lacking the pyrin-like protein M013 is sensed in human myeloid cells by both NLRP3 and multiple Toll-like receptors, which independently activate the inflammasome and NF-κB innate response pathways.

    Science.gov (United States)

    Rahman, Masmudur M; McFadden, Grant

    2011-12-01

    The myxoma virus (MYXV)-encoded pyrin domain-containing protein M013 coregulates inflammatory responses mediated by both the inflammasome and the NF-κB pathways. Infection of human THP-1 monocytic cells with a MYXV construct deleted for the M013 gene (vMyxM013-KO), but not the parental MYXV, activates both the inflammasome and NF-κB pathways and induces a spectrum of proinflammatory cytokines and chemokines, like interleukin-1β (IL-1β), tumor necrosis factor (TNF), IL-6, and monocyte chemoattractant protein 1. Here, we report that vMyxM013-KO virus-mediated activation of inflammasomes and secretion of IL-1β are dependent on the adaptor protein ASC, caspase-1, and NLRP3 receptor. However, vMyxM013-KO virus-mediated activation of NF-κB signaling, which induces TNF secretion, was independent of ASC, caspase-1, and either the NLRP3 or AIM2 inflammasome receptors. We also report that early synthesis of pro-IL-1β in response to vMyxM013-KO infection is dependent upon the components of the inflammasome complex. Activation of the NLRP3 inflammasome and secretion of IL-1β was also dependent on the release of cathepsin B and production of reactive oxygen species (ROS). By using small interfering RNA screening, we further demonstrated that, among the RIG-I-like receptors (RLRs) and Toll-like receptors (TLRs), only TLR2, TLR6, TLR7, and TLR9 contribute to the NF-κB-dependent secretion of TNF and the inflammasome-dependent secretion of IL-1β in response to vMyxM013-KO virus infection. Additionally, we demonstrate that early triggering of the mitogen-activated protein kinase pathway by vMyxM013-KO virus infection of THP-1 cells plays a critical common upstream role in the coordinate induction of both NF-κB and inflammasome pathways. We conclude that an additional cellular sensor(s)/receptor(s) in addition to the known RLRs/TLRs plays a role in the M013 knockout virus-induced activation of NF-κB pathway signaling, but the activation of inflammasomes entirely depends

  4. DMPD: Adipose tissue as an immunological organ: Toll-like receptors, C1q/TNFs andCTRPs. [Dynamic Macrophage Pathway CSML Database

    Lifescience Database Archive (English)

    Full Text Available 17681884 Adipose tissue as an immunological organ: Toll-like receptors, C1q/TNFs an...ng) (.svg) (.html) (.csml) Show Adipose tissue as an immunological organ: Toll-like receptors, C1q/TNFs andC...TRPs. PubmedID 17681884 Title Adipose tissue as an immunological organ: Toll-like

  5. Enhanced interleukin-1beta production of PBMCs from patients with gout after stimulation with Toll-like receptor-2 ligands and urate crystals

    NARCIS (Netherlands)

    Mylona, E.E.; Mouktaroudi, M.; Crisan, T.O.; Makri, S.; Pistiki, A.; Georgitsi, M.; Savva, A.; Netea, M.G.; Meer, J.W. van der; Giamarellos-Bourboulis, E.J.; Joosten, L.A.B.

    2012-01-01

    ABSTRACT: INTRODUCTION: Monosodium urate monohydrate (MSU) crystals synergize with various toll-like receptor (TLR) ligands to induce cytokine production via activation of the NOD-like receptor (NLR) family, pyrin domain-containing 3 (NLPR3) inflammasome. This has been demonstrated in vitro using hu

  6. Toll-like receptor 4 dependent responses to lung injury in a murine model of pulmonary contusion

    OpenAIRE

    2009-01-01

    Blunt chest trauma resulting in pulmonary contusion with an accompanying acute inflammatory response is a common but poorly understood injury. We previously demonstrated that toll-like receptor 2 participates in the inflammatory response to lung injury. We hypothesized that the toll-like receptor 4, in a MyD88-dependent manner, may also participate in the response to lung injury. To investigate this, we used a model of pulmonary contusion in the mouse that is similar to that observed clinical...

  7. Ketamine inhibits tumor necrosis factor-alpha and interleukin-6 gene expressions in lipopolysaccharide-stimulated macrophages through suppression of toll-like receptor 4-mediated c-Jun N-terminal kinase phosphorylation and activator protein-1 activation.

    Science.gov (United States)

    Wu, Gone-Jhe; Chen, Ta-Liang; Ueng, Yune-Fang; Chen, Ruei-Ming

    2008-04-01

    Our previous study showed that ketamine, an intravenous anesthetic agent, has anti-inflammatory effects. In this study, we further evaluated the effects of ketamine on the regulation of tumor necrosis factor-alpha (TNF-alpha) and interlukin-6 (IL-6) gene expressions and its possible signal-transducing mechanisms in lipopolysaccharide (LPS)-activated macrophages. Exposure of macrophages to 1, 10, and 100 microM ketamine, 100 ng/ml LPS, or a combination of ketamine and LPS for 1, 6, and 24 h was not cytotoxic to macrophages. A concentration of 1000 microM of ketamine alone or in combined treatment with LPS caused significant cell death. Administration of LPS increased cellular TNF-alpha and IL-6 protein levels in concentration- and time-dependent manners. Meanwhile, treatment with ketamine concentration- and time-dependently alleviated the enhanced effects. LPS induced TNF-alpha and IL-6 mRNA syntheses. Administration of ketamine at a therapeutic concentration (100 microM) significantly inhibited LPS-induced TNF-alpha and IL-6 mRNA expressions. Application of toll-like receptor 4 (TLR4) small interfering (si)RNA into macrophages decreased cellular TLR4 levels. Co-treatment of macrophages with ketamine and TLR4 siRNA decreased the LPS-induced TNF-alpha and IL-6 productions more than alone administration of TLR4 siRNA. LPS stimulated phosphorylation of c-Jun N-terminal kinase and translocation of c-Jun and c-Fos from the cytoplasm to nuclei. However, administration of ketamine significantly decreased LPS-induced activation of c-Jun N-terminal kinase and translocation of c-Jun and c-Fos. LPS increased the binding of nuclear extracts to activator protein-1 consensus DNA oligonucleotides. Administration of ketamine significantly ameliorated LPS-induced DNA binding activity of activator protein-1. Therefore, a clinically relevant concentration of ketamine can inhibit TNF-alpha and IL-6 gene expressions in LPS-activated macrophages. The suppressive mechanisms occur through

  8. Toll-Like Receptor 4 Decoy, TOY, Attenuates Gram-Negative Bacterial Sepsis

    OpenAIRE

    Keehoon Jung; Jung-Eun Lee; Hak-Zoo Kim; Ho Min Kim; Beom Seok Park; Seong-Ik Hwang; Jie-Oh Lee; Sun Chang Kim; Gou Young Koh

    2009-01-01

    Lipopolysaccharide (LPS), the Gram-negative bacterial outer membrane glycolipid, induces sepsis through its interaction with myeloid differentiation protein-2 (MD-2) and Toll-like receptor 4 (TLR4). To block interaction between LPS/MD-2 complex and TLR4, we designed and generated soluble fusion proteins capable of binding MD-2, dubbed TLR4 decoy receptor (TOY) using 'the Hybrid leucine-rich repeats (LRR) technique'. TOY contains the MD-2 binding ectodomain of TLR4, the LRR motif of hagfish va...

  9. Innate immunity, Toll-like receptors, and atherosclerosis: mouse models and methods.

    Science.gov (United States)

    Sorrentino, Rosalinda; Arditi, Moshe

    2009-01-01

    Chronic inflammation and aberrant lipid metabolism represent hallmarks of atherosclerosis. Innate immunity critically depends upon Toll-like receptor (TLR) signalling. Recent data directly implicate signalling by TLR4 and TLR2 in the pathogenesis of atherosclerosis. The role that TLRs play in the pathogenesis of atherosclerosis can be assessed by using several animal models, which provide a double genetic deficiency in TLRs and molecules implicated in the lipid metabolism, such as ApoE or LDL receptor. Furthermore, a more recent technique, such as the bone marrow transplantation (BMT), can be a useful and straightforward method to elucidate the role of stromal versus hematopoietic cells in the acceleration of the atheroma.

  10. Potentiation and tolerance of toll-like receptor priming in human endothelial cells.

    Science.gov (United States)

    Koch, Stephen R; Lamb, Fred S; Hellman, Judith; Sherwood, Edward R; Stark, Ryan J

    2017-02-01

    Repeated challenge of lipopolysaccharide (LPS) alters the response to subsequent LPS exposures via modulation of toll-like receptor 4 (TLR4). Whether activation of other TLRs can modulate TLR4 responses, and vice versa, remains unclear. Specifically with regards to endothelial cells, a key component of innate immunity, the impact of TLR cross-modulation is unknown. We postulated that TLR2 priming (via Pam3Csk4) would inhibit TLR4-mediated responses while TLR3 priming (via Poly I:C) would enhance subsequent TLR4-inflammatory signaling. We studied human umbilical vein endothelial cells (HUVECs) and neonatal human dermal microvascular endothelial cells (HMVECs). Cells were primed with a combination of Poly I:C (10 μg/ml), Pam3Csk4 (10 μg/ml), or LPS (100 ng/ml), then washed and allowed to rest. They were then rechallenged with either Poly I:C, Pam3Csk4 or LPS. Endothelial cells showed significant tolerance to repeated LPS challenge. Priming with Pam3Csk4 also reduced the response to secondary LPS challenge in both cell types, despite a reduced proinflammatory response to Pam3Csk4 in HMVECs compared to HUVECs. Poly I:C priming enhanced inflammatory and interferon producing signals upon Poly I:C or LPS rechallenge, respectively. Poly I:C priming induced interferon regulatory factor 7, leading to enhancement of interferon production. Finally, both Poly I:C and LPS priming induced significant changes in receptor-interacting serine/threonine-protein kinase 1 activity. Pharmacological inhibition of receptor-interacting serine/threonine-protein kinase 1 or interferon regulatory factor 7 reduced the potentiated phenotype of TLR3 priming on TLR4 rechallenge. These results demonstrate that in human endothelial cells, prior activation of TLRs can have a significant impact on subsequent exposures and may contribute to the severity of the host response.

  11. Toll-like receptors gene polymorphisms may confer increased susceptibility to breast cancer development.

    Science.gov (United States)

    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.

  12. Immune Adjuvant Effect of Molecularly-defined Toll-Like Receptor Ligands

    Directory of Open Access Journals (Sweden)

    Deana N. Toussi

    2014-04-01

    Full Text Available 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.

  13. The role of Toll-like receptor 2 in inflammation and fibrosis during progressive renal injury.

    Directory of Open Access Journals (Sweden)

    Jaklien C Leemans

    Full Text Available Tissue fibrosis and chronic inflammation are common causes of progressive organ damage, including progressive renal disease, leading to loss of physiological functions. Recently, it was shown that Toll-like receptor 2 (TLR2 is expressed in the kidney and activated by endogenous danger signals. The expression and function of TLR2 during renal fibrosis and chronic inflammation has however not yet been elucidated. Therefore, we studied TLR2 expression in human and murine progressive renal diseases and explored its role by inducing obstructive nephropathy in TLR2(-/- or TLR2(+/+ mice. We found that TLR2 is markedly upregulated on tubular and tubulointerstitial cells in patients with chronic renal injury. In mice with obstructive nephropathy, renal injury was associated with a marked upregulation and change in distribution of TLR2 and upregulation of murine TLR2 danger ligands Gp96, biglycan, and HMGB1. Notably, TLR2 enhanced inflammation as reflected by a significantly reduced influx of neutrophils and production of chemokines and TGF-beta in kidneys of TLR2(-/- mice compared with TLR2(+/+ animals. Although, the obstructed kidneys of TLR2(-/- mice had less interstitial myofibroblasts in the later phase of obstructive nephropathy, tubular injury and renal matrix accumulation was similar in both mouse strains. Together, these data demonstrate that TLR2 can initiate renal inflammation during progressive renal injury and that the absence of TLR2 does not affect the development of chronic renal injury and fibrosis.

  14. Toll like receptor 4 mediates cell death in a mouse MPTP model of Parkinson disease

    Science.gov (United States)

    Noelker, Carmen; Morel, Lydie; Lescot, Thomas; Osterloh, Anke; Alvarez-Fischer, Daniel; Breloer, Minka; Henze, Carmen; Depboylu, Candan; Skrzydelski, Delphine; Michel, Patrick P.; Dodel, Richard C.; Lu, Lixia; Hirsch, Etienne C.; Hunot, Stéphane; Hartmann, Andreas

    2013-01-01

    In mammalians, toll-like receptors (TLR) signal-transduction pathways induce the expression of a variety of immune-response genes, including inflammatory cytokines. It is therefore plausible to assume that TLRs are mediators in glial cells triggering the release of cytokines that ultimately kill DA neurons in the substantia nigra in Parkinson disease (PD). Accordingly, recent data indicate that TLR4 is up-regulated by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) treatment in a mouse model of PD. Here, we wished to evaluate the role of TLR4 in the acute mouse MPTP model of PD: TLR4-deficient mice and wild-type littermates control mice were used for the acute administration way of MPTP or a corresponding volume of saline. We demonstrate that TLR4-deficient mice are less vulnerable to MPTP intoxication than wild-type mice and display a decreased number of Iba1+ and MHC II+ activated microglial cells after MPTP application, suggesting that the TLR4 pathway is involved in experimental PD. PMID:23462811

  15. Toll-Like Receptor 4 Engagement Mediates Prolyl Endopeptidase Release from Airway Epithelia via Exosomes.

    Science.gov (United States)

    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.

  16. Bioinformatics analysis of the structural and evolutionary characteristics for toll-like receptor 15

    Directory of Open Access Journals (Sweden)

    Jinlan Wang

    2016-05-01

    Full Text Available 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.

  17. The role of toll-like receptors (TLRs) in urinary tract infections (UTIs)

    Science.gov (United States)

    Behzadi, Elham

    2016-01-01

    Introduction Urinary Tract Infections (UTIs) are caused by different types of microbial agents such as uropathogenic Escherichia coli (UPEC) and Candida albicans. The presence of strong physical barriers may prevent the breach of pathogens into the urinary tract. However, sometimes the pathogenic microorganisms may pass through the barriers and stimulate the innate and adaptive responses. Among a variety of innate immune responses, Toll-Like Receptors (TLRs) are one of the most unique and interesting molecules regarding UTIs. Thus, the authors have focused their attention on the role of TLRs in urinary tract defense against pathogenic microbial agents such as UPEC and C.albicans through this literature review. Material and methods Several papers regarding UTIs and TLRs including original and review articles were searched by PubMed and Google Scholar. They were studied and the most important aspects in association with the role of TLRs in UTIs were extracted. Additionally, this paper was prepared using the experience of the authors. Results The TLRs 2, 4 and 5 are the most functional molecules that contribute to urinary tract defense system and UTIs. It is incredible that TLRs are able to detect and recognize different parts of microbial components relating to the same pathogen. Besides, the flexibility of the TLR molecules may lead to identification of different types of microorganisms with different signaling pathways. Conclusions Our knowledge associated with TLRs and their activities against microbial causative agents of UTIs may help us to prevent, control and treat UTIs at a higher quality level. PMID:28127459

  18. Toll-like receptor 4-dependent contribution of the immune system to anticancer chemotherapy and radiotherapy.

    Science.gov (United States)

    Apetoh, Lionel; Ghiringhelli, François; Tesniere, Antoine; Obeid, Michel; Ortiz, Carla; Criollo, Alfredo; Mignot, Grégoire; Maiuri, M Chiara; Ullrich, Evelyn; Saulnier, Patrick; Yang, Huan; Amigorena, Sebastian; Ryffel, Bernard; Barrat, Franck J; Saftig, Paul; Levi, Francis; Lidereau, Rosette; Nogues, Catherine; Mira, Jean-Paul; Chompret, Agnès; Joulin, Virginie; Clavel-Chapelon, Françoise; Bourhis, Jean; André, Fabrice; Delaloge, Suzette; Tursz, Thomas; Kroemer, Guido; Zitvogel, Laurence

    2007-09-01

    Conventional cancer treatments rely on radiotherapy and chemotherapy. Such treatments supposedly mediate their effects via the direct elimination of tumor cells. Here we show that the success of some protocols for anticancer therapy depends on innate and adaptive antitumor immune responses. We describe in both mice and humans a previously unrecognized pathway for the activation of tumor antigen-specific T-cell immunity that involves secretion of the high-mobility-group box 1 (HMGB1) alarmin protein by dying tumor cells and the action of HMGB1 on Toll-like receptor 4 (TLR4) expressed by dendritic cells (DCs). During chemotherapy or radiotherapy, DCs require signaling through TLR4 and its adaptor MyD88 for efficient processing and cross-presentation of antigen from dying tumor cells. Patients with breast cancer who carry a TLR4 loss-of-function allele relapse more quickly after radiotherapy and chemotherapy than those carrying the normal TLR4 allele. These results delineate a clinically relevant immunoadjuvant pathway triggered by tumor cell death.

  19. In vitro inflammation inhibition model based on semi-continuous toll-like receptor biosensing.

    Directory of Open Access Journals (Sweden)

    Jin-Woo Jeon

    Full Text Available A chemical inhibition model of inflammation is proposed by semi-continuous monitoring the density of toll-like receptor 1 (TLR1 expressed on mammalian cells following bacterial infection to investigate an in vivo-mimicked drug screening system. The inflammation was induced by adding bacterial lysate (e.g., Pseudomonas aeruginosa to a mammalian cell culture (e.g., A549 cell line. The TLR1 density on the same cells was immunochemically monitored up to three cycles under optimized cyclic bacterial stimulation-and-restoration conditions. The assay was carried out by adopting a cell-compatible immunoanalytical procedure and signal generation method. Signal intensity relative to the background control obtained without stimulation was employed to plot the standard curve for inflammation. To suppress the inflammatory response, sodium salicylate, which inhibits nuclear factor-κB activity, was used to prepare the standard curve for anti-inflammation. Such measurement of differential TLR densities was used as a biosensing approach discriminating the anti-inflammatory substance from the non-effector, which was simulated by using caffeic acid phenethyl ester and acetaminophen as the two components, respectively. As the same cells exposed to repetitive bacterial stimulation were semi-continuously monitored, the efficacy and toxicity of the inhibitors may further be determined regarding persistency against time. Therefore, this semi-continuous biosensing model could be appropriate as a substitute for animal-based experimentation during drug screening prior to pre-clinical tests.

  20. The complement system and toll-like receptors as integrated players in the pathophysiology of atherosclerosis.

    Science.gov (United States)

    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.

  1. SPLUNC1 regulation in airway epithelial cells: role of toll-like receptor 2 signaling

    Directory of Open Access Journals (Sweden)

    Smith Sean

    2010-11-01

    Full Text Available Abstract Background Respiratory infections including Mycoplasma pneumoniae (Mp contribute to various chronic lung diseases. We have shown that mouse short palate, lung, and nasal epithelium clone 1 (SPLUNC1 protein was able to inhibit Mp growth. Further, airway epithelial cells increased SPLUNC1 expression upon Mp infection. However, the mechanisms underlying SPLUNC1 regulation remain unknown. In the current study, we investigated if SPLUNC1 production following Mp infection is regulated through Toll-like receptor 2 (TLR2 signaling. Methods Airway epithelial cell cultures were utilized to reveal the contribution of TLR2 signaling including NF-κB to SPLUNC1 production upon bacterial infection and TLR2 agonist stimulation. Results Mp and TLR2 agonist Pam3CSK4 increased SPLUNC1 expression in tracheal epithelial cells from wild type, but not TLR2-/- BALB/c mice. RNA interference (short-hairpin RNA of TLR2 in normal human bronchial epithelial cells under air-liquid interface cultures significantly reduced SPLUNC1 levels in Mp-infected or Pam3CSK4-treated cells. Inhibition and activation of NF-κB pathway decreased and increased SPLUNC1 production in airway epithelial cells, respectively. Conclusions Our data for the first time suggest that airway epithelial TLR2 signaling is pivotal in mycoplasma-induced SPLUNC1 production, thus improving our understanding of the aberrant SPLUNC1 expression in airways of patients suffering from chronic lung diseases with bacterial infections.

  2. Kidney Expression of Toll Like Receptors in Lupus Nephritis: Quantification and Clinicopathological Correlations

    Directory of Open Access Journals (Sweden)

    Fabrizio Conti

    2016-01-01

    Full Text Available 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.

  3. Methemoglobin Is an Endogenous Toll-Like Receptor 4 Ligand—Relevance to Subarachnoid Hemorrhage

    Directory of Open Access Journals (Sweden)

    Min Seong Kwon

    2015-03-01

    Full Text Available Neuroinflammation is a well-recognized consequence of subarachnoid hemorrhage (SAH, and may be responsible for important complications of SAH. Signaling by Toll-like receptor 4 (TLR4-mediated nuclear factor κB (NFκB in microglia plays a critical role in neuronal damage after SAH. Three molecules derived from erythrocyte breakdown have been postulated to be endogenous TLR4 ligands: methemoglobin (metHgb, heme and hemin. However, poor water solubility of heme and hemin, and lipopolysaccharide (LPS contamination have confounded our understanding of these molecules as endogenous TLR4 ligands. We used a 5-step process to obtain highly purified LPS-free metHgb, as confirmed by Fourier Transform Ion Cyclotron Resonance mass spectrometry and by the Limulus amebocyte lysate assay. Using this preparation, we show that metHgb is a TLR4 ligand at physiologically relevant concentrations. metHgb caused time- and dose-dependent secretion of the proinflammatory cytokine, tumor necrosis factor α (TNFα, from microglial and macrophage cell lines, with secretion inhibited by siRNA directed against TLR4, by the TLR4-specific inhibitors, Rs-LPS and TAK-242, and by anti-CD14 antibodies. Injection of purified LPS-free metHgb into the rat subarachnoid space induced microglial activation and TNFα upregulation. Together, our findings support the hypothesis that, following SAH, metHgb in the subarachnoid space can promote widespread TLR4-mediated neuroinflammation.

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

    Science.gov (United States)

    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.

  5. Toll-Like Receptor (TLR 2 and TLR4 Gene Expression in Canine Heart

    Directory of Open Access Journals (Sweden)

    A. Linde

    2007-01-01

    Full Text Available Toll-like receptors (TLRs are archetypal pattern recognition receptors of immediate importance for an efficacious innate immune response. TLRs exhibit marked differential tissue activity and their levels within a discrete cell type can be highly dynamic. Of 13 known mammalian paralogues, three TLRs have been identified in the dog. Although cardiac TLR expression has been reported in other species, this study is the first to present evidence that these innate immune receptors are expressed in the canine heart. Heart tissue samples from all four chambers were collected from healthy dogs immediately after euthanasia and stored at -80ºC until analysis. Total RNA was extracted with TRI Regent. Specific primers were designed for amplification of canine TLR2 and TLR4 based on previously reported sequences for these genes. Reverse transcription was performed with M-MLV reverse transcriptase. PCR amplification was performed and PCR products analyzed by agarose gel electrophoresis. Bands were excised from the gel and the DNA isolated and cloned using the TA Cloning® Kit. The correct sequence for each product was verified by nucleotide sequencing. TLR4 expression was detected in the left ventricle and right atrium; TLR2 was detectable at low levels in the right atrium only. Identity of the RT-PCR products was confirmed by sequencing. Our findings show that at least two TLR paralogues- namely TLR2 and TLR4 - are expressed in the canine heart. Additional studies are warranted to determine these immune receptors' potential implication in the development of naturally occurring heart disease in the dog.

  6. Toll-like receptors are part of the innate immune defense system of sponges (demospongiae: Porifera).

    Science.gov (United States)

    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

  7. Short-term treatment with metformin suppresses toll like receptors (TLRs) activity in isoproterenol-induced myocardial infarction in rat: are AMPK and TLRs connected?

    Science.gov (United States)

    Soraya, Hamid; Farajnia, Safar; Khani, Sajjad; Rameshrad, Maryam; Khorrami, Arash; Banani, Armita; Maleki-Dizaji, Nasrin; Garjani, Alireza

    2012-12-01

    AMP-activated protein kinase (AMPK) is a key sensor of cellular energy. The activation of AMPK by metformin prevents cardiac remodeling after myocardial infarction (MI). Besides, the innate immune response through TLRs is activated during MI. In the present study, the effects of short-term treatment with metformin on TLRs activity and its relation with AMPK in isoproterenol-induced MI were assessed in rats. To induce MI, a subcutaneous injection of isoproterenol was given to Wistar rats for two consecutive days. Metformin (25, 50, and 100mg/kg) was orally administered to rats twice daily for two days. Interstitial fibrosis was dose-dependently attenuated in the treated groups in comparison to the MI group (score: 1.25 ± 0.28 with 100 mg/kg metformin versus 3.5 ± 0.28; Pmetformin reduced TLR-dependent inflammatory cytokines as indexed by reduced myocardial levels of TNFα (maximum 68%; Pmetformin, but not with 25 and 50mg/kg. This was associated with a remarkable suppression of TLR4 expression and reduction of protein level of TLRs adapter protein, MyD88 (Pmetformin and the subsequent suppression of TLRs activity could be considered as a target in protecting the infarcted heart, which may indicate a link between AMPK and TLRs.

  8. Live Streptococcus pneumoniae, Haemophilus influenzae, and Neisseria meningitidis activate the inflammatory response trhough Toll-like receptors 2, 4, and 9 in species-specific patterns

    DEFF Research Database (Denmark)

    Mogensen, T.H.; Paludan, Søren Riis; Kilian, Mogens

    2006-01-01

    activation by live bacteria. Here, we demonstrate that live Streptococcus pneumoniae, Haemophilus influenzae type b, and Neisseria meningitidis, the three principal causes of bacterial meningitis, use distinct sets of TLRs to trigger the inflammatory response. Using human embryonic kidney 293 cell lines......, each overexpressing one type of TLR, we found that S. pneumoniae triggered activation of the transcription factor nuclear factor-kappaB and expression of interleukin-8, only in cells expressing TLR2 or -9. The same response was evoked by H. influenzae in cells expressing TLR2 or -4 and by N....... meningitidis in cells expressing TLR2, -4, or -9. It is interesting that the ability of S. pneumoniae and N. meningitidis to activate TLR9 was severely attenuated when bacteria had been heat-inactivated prior to stimulation of the cells. In human peripheral blood mononuclear cells, we blocked TLR2, -4, or -9...

  9. Development of immune memory to glial brain tumours after tumour regression induced by immunotherapeutic Toll-like receptor 7/8 activation

    NARCIS (Netherlands)

    Stathopoulos, A.; Pretto, C.; Devilliers, L.; Hofman, F.M.; Kruse, C.A.; Jadus, M.; Chen, T.C.; Schijns, V.E.J.C.

    2012-01-01

    The efficacy of immunotherapeutic TLR7/8 activation by resiquimod (R848) was evaluated in vivo, in the CNS-1 rat glioma model syngeneic to Lewis rats. The immune treatment was compared with cytotoxic cyclophosphamide chemotherapy, and as well, was compared with the combination cytotoxic and immunoth

  10. Activin suppresses LPS-induced Toll-like receptor, cytokine and inducible nitric oxide synthase expression in normal human melanocytes by inhibiting NF-κB and MAPK pathway activation.

    Science.gov (United States)

    Kim, Young Il; Park, Seung-Won; Kang, In Jung; Shin, Min Kyung; Lee, Mu-Hyoung

    2015-10-01

    Activins are dimeric growth and differentiation factors that belong to the transforming growth factor (TGF)-β superfamily of structurally related signaling proteins. In the present study, we examined the mechanisms through which activin regulates the lipopolysaccharide (LPS)-induced transcription of Toll-like receptors (TLRs), cytokines and inducible nitric oxide synthase (iNOS) in human melanocytes, as well as the involvement of nuclear factor (NF)-κB and mitogen-activated protein kinase (MAPK) signaling. Cell proliferation was analyzed by cell viability assay, mRNA expression was detected by RT-qPCR, and protein expression was measured by western blot analysis. LPS increased the mRNA expression of TLRs (TLR1-10) and cytokines [interleukin (IL)-1β, IL-6, IL-8 and TNF-α], as well as the mRNA and protein expression of iNOS. Activin decreased the LPS-induced TLR and cytokine mRNA expression, as well as the LPS-induced iNOS mRNA and protein expression. In addition, activin suppressed NF-κB p65 activation and blocked inhibitor of NF-κB (IκBα) degradation in LPS-stimulated melanocytes, and reduced LPS-induced p38 MAPK and MEK/ERK activation. On the whole, our results demonstrated that activin inhibited TLR and cytokine expression in LPS-activated normal human melanocytes and suppressed LPS-induced iNOS gene expression. Moreover, the anti-inflammatory effects of activin were shown to be mediated through the suppression of NF-κB and MAPK signaling, resulting in reduced TLR and iNOS expression, and in the inhibition of inflammatory cytokine expression.

  11. Bilirubin inhibits the up-regulation of inducible nitric oxide synthase by scavenging reactive oxygen species generated by the toll-like receptor 4-dependent activation of NADPH oxidase.

    Science.gov (United States)

    Idelman, Gila; Smith, Darcey L H; Zucker, Stephen D

    2015-08-01

    It has been previously shown that bilirubin prevents the up-regulation of inducible nitric oxide synthase (iNOS) in response to LPS. The present study examines whether this effect is exerted through modulation of Toll-Like Receptor-4 (TLR4) signaling. LPS-stimulated iNOS and NADPH oxidase (Nox) activity in RAW 264.7 murine macrophages was assessed by measuring cellular nitrate and superoxide ( [Formula: see text] ) production, respectively. The generation of both nitrate and [Formula: see text] in response to LPS was suppressed by TLR4 inhibitors, indicating that activation of iNOS and Nox is TLR4-dependent. While treatment with superoxide dismutase (SOD) and bilirubin effectively abolished LPS-mediated [Formula: see text] production, hydrogen peroxide and nitrate release were inhibited by bilirubin and PEG-catalase, but not SOD, supporting that iNOS activation is primarily dependent upon intracellular H2O2. LPS treatment increased nuclear translocation of the redox-sensitive transcription factor Hypoxia Inducible Factor-1α (HIF-1α), an effect that was abolished by bilirubin. Cells transfected with murine iNOS reporter constructs in which the HIF-1α-specific hypoxia response element was disrupted exhibited a blunted response to LPS, supporting that HIF-1α mediates Nox-dependent iNOS expression. Bilirubin, but not SOD, blocked the cellular production of interferon-β, while interleukin-6 production remained unaffected. These data support that bilirubin inhibits the TLR4-mediated up-regulation of iNOS by preventing activation of HIF-1α through scavenging of Nox-derived reactive oxygen species. Bilirubin also suppresses interferon-β release via a ROS-independent mechanism. These findings characterize potential mechanisms for the anti-inflammatory effects of bilirubin.

  12. Minor modifications to the phosphate groups and the C3' acyl chain length of lipid A in two Bordetella pertussis strains, BP338 and 18-323, independently affect Toll-like receptor 4 protein activation.

    Science.gov (United States)

    Shah, Nita R; Albitar-Nehme, Sami; Kim, Emma; Marr, Nico; Novikov, Alexey; Caroff, Martine; Fernandez, Rachel C

    2013-04-26

    Lipopolysaccharides (LPS) of Bordetella pertussis are important modulators of the immune system. Interaction of the lipid A region of LPS with the Toll-like receptor 4 (TLR4) complex causes dimerization of TLR4 and activation of downstream nuclear factor κB (NFκB), which can lead to inflammation. We have previously shown that two strains of B. pertussis, BP338 (a Tohama I-derivative) and 18-323, display two differences in lipid A structure. 1) BP338 can modify the 1- and 4'-phosphates by the addition of glucosamine (GlcN), whereas 18-323 cannot, and 2) the C3' acyl chain in BP338 is 14 carbons long, but only 10 or 12 carbons long in 18-323. In addition, BP338 lipid A can activate TLR4 to a greater extent than 18-323 lipid A. Here we set out to determine the genetic reasons for the differences in these lipid A structures and the contribution of each structural difference to the ability of lipid A to activate TLR4. We show that three genes of the lipid A GlcN modification (Lgm) locus, lgmA, lgmB, and lgmC (previously locus tags BP0399-BP0397), are required for GlcN modification and a single amino acid difference in LpxA is responsible for the difference in C3' acyl chain length. Furthermore, by introducing lipid A-modifying genes into 18-323 to generate isogenic strains with varying penta-acyl lipid A structures, we determined that both modifications increase TLR4 activation, although the GlcN modification plays a dominant role. These results shed light on how TLR4 may interact with penta-acyl lipid A species.

  13. Adsorption of Toll-Like Receptor 4 Agonist to Alum-Based Tetanus Toxoid Vaccine Dampens Pro-T Helper 2 Activities and Enhances Antibody Responses.

    Science.gov (United States)

    Bortolatto, Juliana; Mirotti, Luciana; Rodriguez, Dunia; Gomes, Eliane; Russo, Momtchilo

    2015-01-01

    Aluminum salts gels (alum) are TLR-independent adjuvants and have been used to boost antibody responses in alum-based vaccines such as diphtheria, pertussis, and tetanus toxoid (DPT) triple vaccine. However, the pro-Th2 activity of alum-based vaccine formulations has not been fully appreciated. Here we found that alum-based tetanus toxoid (TT) vaccine was biased toward a Th-2 profile as shown by TT-induced airway eosinophilic inflammation, type 2 cytokine production, and high levels of IgE anaphylactic antibodies. The adsorption into alum of prototypic TLR4 agonists such as lipopolysaccharides (LPS) derived from Escherichia coli consistently dampened TT-induced Th2 activities without inducing IFNγ or Th1-like responses in the lung. Conversely, adsorption of monophosphoryl lipid A (MPLA) extracted from Salmonella minnesota, which is a TIR-domain-containing adapter-inducing interferon-β- (TRIF-) biased TLR4 agonist, was less effective in decreasing Th-2 responses. Importantly, in a situation with antigenic competition (OVA plus TT), TT-specific IgG1 or IgG2a was decreased compared with TT sensitization. Notably, LPS increased the production of IgG1 and IgG2a TT-specific antibodies. In conclusion, the addition of LPS induces a more robust IgG1 and IgG2a TT-specific antibody production and concomitantly decreases Th2-cellular and humoral responses, indicating a potential use of alum/TLR-based vaccines.

  14. MD-2 interacts with Lyn kinase and is tyrosine phosphorylated following LPS-induced activation of the Toll-like receptor 4 signaling pathway

    Science.gov (United States)

    Gray, Pearl; Dagvadorj, Jargalsaikhan; Michelsen, Kathrin S.; Brikos, Constantinos; Rentsendorj, Altan; Town, Terrence; Crother, Timothy R.; Arditi, Moshe

    2011-01-01

    Stimulation with LPS induces tyrosine phosphorylation of numerous proteins involved in the TLR signaling pathway. In this study, we demonstrate that MD-2 is also tyrosine phosphorylated following LPS stimulation. LPS-induced tyrosine phosphorylation of MD-2 is specific, it is blocked by the tyrosine kinase inhibitor, Herbimycin A, and by an inhibitor of endocytosis, Cytochalsin-D, suggesting that MD-2 phosphorylation occurs during trafficking of MD2 and not on cell surface. Furthermore, we identify two possible phospho-accepting tyrosine residues at positions 22 and 131. Mutant proteins in which these tyrosines were changed to phenylalanine have reduced phosphorylation and significantly diminished ability to activate NF-κB in response to LPS. In addition, MD2 co-precipitates and colocalizes with Lyn kinase, most likely in ER. A Lyn-binding peptide inhibitor abolished MD2 tyrosine phosphorylation, suggesting that Lyn is a likely candidate to be the kinase required for MD-2 tyrosine phophorylation. Our study demonstrates that tyrosine phosphorylation of MD-2 is important for signaling following exposure to LPS and underscores the importance of this event in mediating an efficient and prompt immune response. PMID:21918188

  15. Dihydroartemisinin inhibits activation of the Toll-like receptor 4 signaling pathway and production of type I interferon in spleen cells from lupus-prone MRL/lpr mice.

    Science.gov (United States)

    Huang, Xueqin; Xie, Zhijun; Liu, Fenfen; Han, Chunwen; Zhang, Dongyu; Wang, Dawei; Bao, Xi; Sun, Jing; Wen, Chengping; Fan, Yongsheng

    2014-09-01

    Systemic lupus erythematosus (SLE) is a multisystem autoimmune disease characterized by various immunological abnormalities. Dihydroartemisinin (DHA), a metabolite of artemisinin, has been recently reported to exhibit immunosuppressive properties. The present study aims to determine the effects of DHA on spleen cell activation triggered by lipopolysaccharide (LPS) and investigate the effects of DHA on LPS-induced activation of the Toll-like receptor 4 (TLR4)/interferon regulatory factor (IRF) signaling pathway. Spleen cells from lupus-prone MRL/lpr mice were isolated, prepared and cultured. Cells were treated with LPS alone or LPS with DHA, and spleen cell proliferation was analyzed using MTS assay. Protein expressions of TLR4, IRF3, and IRF7 were analyzed by Western blot. IRF3 phosphorylation was also determined. Gene expression levels of IFN-α and IFN-β were measured using real-time PCR, and protein levels in cells' supernatants were determined by ELISA. DHA was found to inhibit LPS-induced spleen cell proliferation, decrease LPS-induced protein expression of TLR4, and inhibit IRF3 phosphorylation. Furthermore, LPS significantly induced IRF3 expression and slightly increased IRF7 expression in the nucleus of spleen cells, which was accompanied by enhanced IFN-α and IFN-β production. DHA inhibited the effects of LPS in spleen cells of MRL/lpr mice. Taken together, the data obtained reveal that DHA inhibits LPS-induced cell activation possibly by suppressing the TLR4/IRF/IFN pathway in spleen cells of MRL/lpr mice. These data suggest that DHA has the potential therapeutic utility for the treatment of SLE.

  16. A novel pro-inflammatory protein of Streptococcus suis 2 induces the Toll-like receptor 2-dependent expression of pro-inflammatory cytokines in RAW 264.7 macrophages via activation of ERK1/2 pathway.

    Science.gov (United States)

    Zhang, Qiang; Yang, Yujie; Yan, Shuxian; Liu, Jiantao; Xu, Zhongmin; Yu, Junping; Song, Yajing; Zhang, Anding; Jin, Meilin

    2015-01-01

    Streptococcus suis 2 is an important swine pathogen and an emergent zoonotic pathogen. Excessive inflammation caused by S. suis is responsible for the high levels of early mortality observed in septic shock-like syndrome cases. However, the mechanisms through which S. suis 2 (SS2) causes excessive inflammation remain unclear. Thus, this study aimed to identify novel pro-inflammatory mediators that play important roles in the development of therapies against SS2 infection. In this study, the novel pro-inflammatory protein HP0459, which was encoded by the SSUSC84_0459 gene, was discovered. The stimulation of RAW 264.7 macrophages with recombinant HP0459 protein induced the expression of pro-inflammatory cytokines (IL-1β, MCP-1 and TNF-α). Compared with the wild-type (WT) strain, the isogenic knockout of HP0459 in SS2 led to reduced production of pro-inflammatory cytokines in RAW264.7 macrophages and in vivo. The pro-inflammatory activity of HP0459 was significantly reduced by an antibody against Toll-like receptor 2 (TLR2) in RAW264.7 macrophages and was lower in TLR2-deficient (TLR2-/-) macrophages than in WT macrophages. Furthermore, specific inhibitors of the extracellular signal-regulated kinase 1/2 (ERK1/2) pathways significantly decreased the HP0459-induced pro-inflammatory cytokine production, and a western blot assay showed that HP0459 stimulation induced the activation of the ERK1/2 pathway. Taken together, our data indicate that HP0459 is a novel pro-inflammatory mediator of SS2 and induces TLR2-dependent pro-inflammatory activity in RAW264.7 macrophages through the ERK1/2 pathway.

  17. Toll-like receptor gene polymorphisms are associated with allergic rhinitis: a case control study

    Directory of Open Access Journals (Sweden)

    Nilsson Daniel

    2012-08-01

    Full Text Available Abstract Background The Toll-like receptor proteins are important in host defense and initiation of the innate and adaptive immune responses. A number of studies have identified associations between genetic variation in the Toll-like receptor genes and allergic disorders such as asthma and allergic rhinitis. The present study aim to search for genetic variation associated with allergic rhinitis in the Toll-like receptor genes. Methods A first association analysis genotyped 73 SNPs in 182 cases and 378 controls from a Swedish population. Based on these results an additional 24 SNPs were analyzed in one Swedish population with 352 cases and 709 controls and one Chinese population with 948 cases and 580 controls. Results The first association analysis identified 4 allergic rhinitis-associated SNPs in the TLR7-TLR8 gene region. Subsequent analysis of 24 SNPs from this region identified 7 and 5 significant SNPs from the Swedish and Chinese populations, respectively. The corresponding risk-associated haplotypes are significant after Bonferroni correction and are the most common haplotypes in both populations. The associations are primarily detected in females in the Swedish population, whereas it is seen in males in the Chinese population. Further independent support for the involvement of this region in allergic rhinitis was obtained from quantitative skin prick test data generated in both populations. Conclusions Haplotypes in the TLR7-TLR8 gene region were associated with allergic rhinitis in one Swedish and one Chinese population. Since this region has earlier been associated with asthma and allergic rhinitis in a Danish linkage study this speaks strongly in favour of this region being truly involved in the development of this disease.

  18. MiRNA-181a regulates Toll-like receptor agonist-induced inflammatory response in human fibroblasts

    OpenAIRE

    Galicia, Johnah C.; Naqvi, Afsar R; Ko, Ching-Chang; Nares, Salvador; Khan, Asma A.

    2014-01-01

    MicroRNAs (miRNA) regulate the synthesis of cytokines in response to Toll-like receptor (TLR) activation. Our recent microarray study comparing normal and inflamed human dental pulps showed that miRNA-181 (miR-181) family is differentially expressed in the presence of inflammation. Prior studies have reported that the dental pulp, which is composed primarily of TLR4/2+ fibroblasts, expresses elevated levels of cytokines including Interleukin-8 (IL-8) when inflamed. In this study, we employed ...

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

    Directory of Open Access Journals (Sweden)

    Lucía Pérez-Regidor

    2016-09-01

    Full Text Available 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.

  20. Betaine inhibits Toll-like receptor 4 expression in rats with ethanol-induced liver injury

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    AIM:To test whether ethanol feeding could induce Toll-like receptor 4(TLR4)responses,assess the hepatoprotective effect of betaine and its inhibitive effect on TLR4 in animal models of alcoholic liver injury.METHODS:Forty-eight female Sprague-Dawley rats were randomly divided into four groups as control,model,low and high dose betaine groups.Except control group,all rats were fed with high fat-containing diet plus ethanol and fish oil gavages for 8 wk.Betaine was administered intragastrically after exposure...

  1. DMPD: Toll-like receptors and Type I interferons. [Dynamic Macrophage Pathway CSML Database

    Lifescience Database Archive (English)

    Full Text Available . Pathway - PNG File (.png) SVG File (.svg) HTML File (.html) CSML File (.csml) Open .csml file with CIOPlayer Open .csm...m. 2007 May 25;282(21):15319-23. Epub 2007 Mar 29. (.png) (.svg) (.html) (.csml) Show Toll-like receptors an...l file with CIOPlayer - ※CIO Playerのご利用上の注意 Open .csml file with CIO Open .csml file with CIO - ※CIOのご利用上の注意 ...

  2. DMPD: A Toll-like receptor in horseshoe crabs. [Dynamic Macrophage Pathway CSML Database

    Lifescience Database Archive (English)

    Full Text Available mmunol Rev. 2004 Apr;198:106-15. (.png) (.svg) (.html) (.csml) Show A Toll-like receptor in horseshoe crabs....blication Immunol Rev. 2004 Apr;198:106-15. Pathway - PNG File (.png) SVG File (....svg) HTML File (.html) CSML File (.csml) Open .csml file with CIOPlayer Open .csml file with CIOPlayer - ※CI...O Playerのご利用上の注意 Open .csml file with CIO Open .csml file with CIO - ※CIOのご利用上の注意 ...

  3. DMPD: Viral recognition by Toll-like receptors. [Dynamic Macrophage Pathway CSML Database

    Lifescience Database Archive (English)

    Full Text Available .svg) HTML File (.html) CSML File (.csml) Open .csml file with CIOPlayer Open .csml file with CIOPlayer - ※C...eb;19(1):33-40. Epub 2007 Mar 2. (.png) (.svg) (.html) (.csml) Show Viral recognition by Toll-like receptors...IO Playerのご利用上の注意 Open .csml file with CIO Open .csml file with CIO - ※CIOのご利用上の注意 ... ...unol. 2007 Feb;19(1):33-40. Epub 2007 Mar 2. Pathway - PNG File (.png) SVG File (

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

    Science.gov (United States)

    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

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

    Science.gov (United States)

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

    2016-01-01

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

  6. Sublingual administration of an adenovirus serotype 5 (Ad5)-based vaccine confirms Toll-like receptor agonist activity in the oral cavity and elicits improved mucosal and systemic cell-mediated responses against HIV antigens despite preexisting Ad5 immunity.

    Science.gov (United States)

    Appledorn, Daniel M; Aldhamen, Yasser A; Godbehere, Sarah; Seregin, Sergey S; Amalfitano, Andrea

    2011-01-01

    HIV/AIDS continue to devastate populations worldwide. Recent studies suggest that vaccines that induce beneficial immune responses in the mucosal compartment may improve the efficacy of HIV vaccines. Adenovirus serotype 5 (Ad5)-based vectors remain a promising platform for the development of effective vaccines. In an effort to improve the efficacy of Ad5-based vaccines, even in the presence of preexisting Ad5 immunity, we evaluated the potential for an Ad5-based HIV vaccine to induce antigen-specific immune responses following sublingual (s.l.) administration, a route not previously tested in regard to Ad-based vaccines. s.l. vaccination with an Ad5-based HIV-Gag vaccine resulted in a significant induction of Gag-specific cytotoxic T-lymphocyte (CTL) responses in both the systemic and the mucosal compartment. We also show that s.l. immunization not only avoided preexisting Ad5 immunity but also elicited a broad repertoire of antigen-specific CTL clones. Additionally, we confirm for the first time that oral delivery of a vaccine expressing a potent Toll-like receptor (TLR) agonist can stimulate innate immune responses through induction of cytokines and chemokines and activation of NK cells, NKT cells, and macrophages in vivo. These results positively correlated with improved antigen-specific CTL responses. These results could be achieved both in Ad5-naïve mice and in mice with preexisting immunity to Ad5. The simplicity of the s.l. vaccination regimen coupled with augmentation of TLR-dependent pathways active in the oral cavity makes s.l. delivery a promising method for HIV vaccine development specifically, as well as for many other vaccine applications in general.

  7. N-acetylcysteine inhibits activation of toll-like receptor 2 and 4 gene expression in the liver and lung after partial hepatic ischemia-reper fusion injur y in mice

    Institute of Scientific and Technical Information of China (English)

    Xin Jin; Lin Wang; He-Shui Wu; Lei Zhang; Chun-You Wang; Yuan Tian; Jing-Hui Zhang

    2007-01-01

    BACKGROUND: Toll-like receptor 2 and 4 (TLR2/4) may play important roles in ischemia-reperfusion (I/R) injury, and N-acetylcysteine (NAC) can prevent the generation of reactive oxygen species (ROS) induced by I/R injury. This study aimed to investigate the changes in TLR2/4 gene expression in the liver and lung after I/R injury with or without NAC pretreatment. METHODS:BALB/c mice were used in a model of partial hepatic I/R injury and randomly assigned to a sham-operated control group (SH), a hepatic ischemia/reperfusion group (I/R) or a NAC pretreated, hepatic I/R group (I/R-NAC). The levels of TNF-α in the portal vein and plasma alanine aminotransferase (ALT) were measured at 1 and 3 hours after reperfusion. The lung wet-to-dry ratio was measured, and the expression of TLR2/4 mRNA and protein in the liver and lung were assessed with RT-PCR and Western blotting at the same time points. RESULTS: Compared with the I/R group, the expression of TLR2/4 mRNA and protein in the liver and lung in the I/R-NAC group was decreased at the same time point (P CONCLUSIONS:TLR2/4 was activated in the liver and lung in the process of partial hepatic I/R injury. NAC inhibited the activation of TLR2/4 and the induction of TNF-αresulting from I/R injury via modulating the redox state, thus it may mitigate liver and lung injury following partial hepatic I/R in mice.

  8. Toll-like receptor 4, a novel signal transducer for lipopolysaccharide

    Institute of Scientific and Technical Information of China (English)

    杨清武; 朱佩芳; 王正国; 蒋建新

    2002-01-01

    LPS activation effect. Finally, for CD14 negative cells, the receptor combined LPS-LBP-sCD14 compound has not yet been identified. Some details indicated that a “co-receptor” for LPS signal transduction must exist. Although standard biochemical approaches, transfection assay, and immunologic tacties were all employed to search for this co-receptor, it has not yet been found. The find of Toll-like receptor 4 (TLR4) provides a new opportunity to study the mechanism of LPS action.

  9. Transition metal sensing by Toll-like receptor-4: next to nickel, cobalt and palladium are potent human dendritic cell stimulators

    NARCIS (Netherlands)

    Rachmawati, D.; Bontkes, H.J.; Verstege, M.I.; Muris, J.; von Blomberg, B.M.E.; Scheper, R.J.; van Hoogstraten, I.M.W.

    2013-01-01

    Background Nickel was recently identified as a potent activator of dendritic cells through ligating with human Toll-like receptor (TLR)-4. Objectives Here, we studied an extended panel of transition metals neighbouring nickel in the periodic table of elements, for their capacity to activate human mo

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

    Science.gov (United States)

    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.

  11. Targeting Toll-like receptor 4 prevents cobalt-mediated inflammation.

    Science.gov (United States)

    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. Lipoteichoic acid induces unique inflammatory responses when compared to other toll-like receptor 2 ligands.

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    Elizabeth M Long

    Full Text Available Toll-like receptors (TLRs recognize evolutionarily-conserved molecular patterns originating from invading microbes. In this study, we were interested in determining if microbial ligands, which use distinct TLR2-containing receptor complexes, represent unique signals to the cell and can thereby stimulate unique cellular responses. Using the TLR2 ligands, R-FSL1, S-FSL1, Pam2CSK4, Pam3CSK4, and lipoteichoic acid (LTA, we demonstrate that these ligands activate NF-kappaB and MAP Kinase pathways with ligand-specific differential kinetics in murine macrophages. Most strikingly, LTA stimulation of these pathways was substantially delayed when compared with the other TLR2 ligands. These kinetics differences were associated with a delay in the LTA-induced expression of a subset of genes as compared with another TLR2 ligand, R-FSL1. However, this did not translate to overall differences in gene expression patterns four hours following stimulation with different TLR2 ligands. We extended this study to evaluate the in vivo responses to distinct TLR2 ligands using a murine model of acute inflammation, which employs intravital microscopy to monitor leukocyte recruitment into the cremaster muscle. We found that, although R-FSL1, S-FSL1, Pam2CSK4, and Pam3CSK4 were all able to stimulate robust leukocyte recruitment in vivo, LTA remained functionally inert in this in vivo model. Therefore distinct TLR2 ligands elicit unique cellular responses, as evidenced by differences in the kinetic profiles of signaling and gene expression responses in vitro, as well as the physiologically relevant differences in the in vivo responses to these ligands.

  13. Toll-Like Receptor 4 Is Essential in the Development of Abdominal Aortic Aneurysm.

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    Chao-Han Lai

    Full Text Available Toll-like receptor (TLR family plays a key role in innate immunity and various inflammatory responses. TLR4, one of the well-characterized pattern-recognition receptors, can be activated by endogenous damage-associated molecular pattern molecules such as high mobility group box 1 (HMGB1 to sustain sterile inflammation. Evidence suggested that blockade of TLR4 signaling may confer protection against abdominal aortic aneurysm (AAA. Herein we aimed to obtain further insight into the mechanism by which TLR4 might promote aneurysm formation. Characterization of the CaCl2-induced AAA model in mice revealed that upregulation of TLR4 expression, localized predominantly to vascular smooth muscle cells (VSMCs, was followed by a late decline during a 28-day period of AAA development. In vitro, TLR4 expression was increased in VSMCs treated with HMGB1. Knockdown of TLR4 by siRNA attenuated HMGB1-enhanced production of proinflammatory cytokines, specifically interleukin-6 and monocyte chemoattractant protein-1 (MCP-1, and matrix-degrading matrix metalloproteinase (MMP-2 from VSMCs. In vivo, two different strains of TLR4-deficient (C57BL/10ScNJ and C3H/HeJ mice were resistant to CaCl2-induced AAA formation compared to their respective controls (C57BL/10ScSnJ and C3H/HeN. Knockout of TLR4 reduced interleukin-6 and MCP-1 levels and HMGB1 expression, attenuated macrophage accumulation, and eventually suppressed MMP production, elastin destruction and VSMC loss. Finally, human AAA exhibited higher TLR4 expression that was localized to VSMCs. These data suggest that TLR4 signaling contributes to AAA formation by promoting a proinflammatory status of VSMCs and by inducing proteinase release from VSMCs during aneurysm initiation and development.

  14. Induction of bacterial lipoprotein tolerance is associated with suppression of toll-like receptor 2 expression.

    LENUS (Irish Health Repository)

    Wang, Jiang Huai

    2012-02-03

    Tolerance to bacterial cell wall components including lipopolysaccharide (LPS) may represent an essential regulatory mechanism during bacterial infection. Two members of the Toll-like receptor (TLR) family, TLR2 and TLR4, recognize the specific pattern of bacterial cell wall components. TLR4 has been found to be responsible for LPS tolerance. However, the role of TLR2 in bacterial lipoprotein (BLP) tolerance and LPS tolerance is unclear. Pretreatment of human THP-1 monocytic cells with a synthetic bacterial lipopeptide induced tolerance to a second BLP challenge with diminished tumor necrosis factor-alpha and interleukin-6 production, termed BLP tolerance. Furthermore, BLP-tolerized THP-1 cells no longer responded to LPS stimulation, indicating a cross-tolerance to LPS. Induction of BLP tolerance was CD14-independent, as THP-1 cells that lack membrane-bound CD14 developed tolerance both in serum-free conditions and in the presence of a specific CD14 blocking monoclonal antibody (MEM-18). Pre-exposure of THP-1 cells to BLP suppressed mitogen-activated protein kinase phosphorylation and nuclear factor-kappaB activation in response to subsequent BLP and LPS stimulation, which is comparable with that found in LPS-tolerized cells, indicating that BLP tolerance and LPS tolerance may share similar intracellular pathways. However, BLP strongly enhanced TLR2 expression in non-tolerized THP-1 cells, whereas LPS stimulation had no effect. Furthermore, a specific TLR2 blocking monoclonal antibody (2392) attenuated BLP-induced, but not LPS-induced, tumor necrosis factor-alpha and interleukin-6 production, indicating BLP rather than LPS as a ligand for TLR2 engagement and activation. More importantly, pretreatment of THP-1 cells with BLP strongly inhibited TLR2 activation in response to subsequent BLP stimulation. In contrast, LPS tolerance did not prevent BLP-induced TLR2 overexpression. These results demonstrate that BLP tolerance develops through down-regulation of TLR2

  15. Intracellular expression of toll-like receptor 4 in neuroblastoma cells and their unresponsiveness to lipopolysaccharide

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    Mori Isamu

    2006-12-01

    Full Text Available Abstract Background Recently it has been reported that, toll-like receptors (TLRs are expressed on a series of tumor cells, such as colon cancer, breast cancer, prostate cancer, melanoma and lung cancer. Although some cancer cells like melanoma cells are known to respond to lipopolysaccharide (LPS via TLR4, not all cancer cells are positive for TLR4. There is little information on the expression and function of TLR4 in neuroblastoma cells. In this study, we investigated the expression of TLR4 in human neuroblastoma NB-1 cell line. Methods Expression and localization of TLR4 were detected by reverse transcription-polymerase chain reaction (RT-PCR and flow cytometric analysis, respectively. Activation of nuclear factor (NF-κB by LPS was detected by degradation of IκB-α and NF-κB luciferase assay. Activation and expression of mitogen-activated protein (MAP kinase and interferon regulatory factor (IRF-3 was detected by immunoblot analysis. Results Human NB-1 neuroblastoma cells expressed intracellular form of TLR4, but not the cell surface form. Further, NB-1 cells express CD14, MD2 and MyD88, which are required for LPS response. However, LPS did not significantly induce NF-κB activation in NB-1 cells although it slightly degraded IκB-α. NB-1 cells expressed no IRF-3, which plays a pivotal role on the MyD88-independent pathway of LPS signaling. Collectively, NB-1 cells are capable to avoid their response to LPS. Conclusion Although human NB-1 neuroblastoma cells possessed all the molecules required for LPS response, they did not respond to LPS. It might be responsible for intracellular expression of TLR4 or lack of IRF-3.

  16. Spinal toll like receptor 3 is involved in chronic pancreatitis-induced mechanical allodynia of rat

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    Feng Quan-Xing

    2011-02-01

    Full Text Available Abstract Background Mechanisms underlying pain in chronic pancreatitis (CP are incompletely understood. Our previous data showed that astrocytes were actively involved. However, it was unclear how astrocytic activation was induced in CP conditions. In the present study, we hypothesized that toll-like receptors (TLRs were involved in astrocytic activation and pain behavior in CP-induced pain. Results To test our hypothesis, we first investigated the changes of TLR2-4 in the rat CP model induced by intrapancreatic infusion of trinitrobenzene sulfonic acid (TNBS. Western blot showed that after TNBS infusion, TLR3, but not TLR2 or TLR4, was increased gradually and maintained at a very high level for up to 5 w, which correlated with the changing course of mechanical allodynia. Double immunostaining suggested that TLR3 was highly expressed on astrocytes. Infusion with TLR3 antisense oligodeoxynucleotide (ASO dose-dependently attenuated CP-induced allodynia. CP-induced astrocytic activation in the spinal cord was also significantly suppressed by TLR3 ASO. Furthermore, real-time PCR showed that IL-1β, TNF-α, IL-6 and monocyte chemotactic protein-1 (MCP-1 were significantly increased in spinal cord of pancreatic rats. In addition, TLR3 ASO significantly attenuated CP-induced up-regulation of IL-1β and MCP-1. Conclusions These results suggest a probable "TLR3-astrocytes-IL-1β/MCP-1" pathway as a positive feedback loop in the spinal dorsal horn in CP conditions. TLR3-mediated neuroimmune interactions could be new targets for treating persistent pain in CP patients.

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

    Science.gov (United States)

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

    2012-09-06

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

  18. Potential role of Toll-like receptors in programming of vascular dysfunction.

    Science.gov (United States)

    Thompson, Jennifer A; Webb, R Clinton

    2013-03-13

    The developmental origins of the metabolic syndrome have been established through the consistent observation that small-for-gestational age and large-for-gestational age fetuses have an increased risk for hypertension and related metabolic disorders later in life. These phenotypes have been reproduced in various species subjected to a range of intrauterine insults and ongoing research is directed towards understanding the underlying molecular mechanisms. Current evidence suggests that the creation of a pro-inflammatory and pro-oxidant intrauterine milieu is a common thread among prenatal factors that have an impact upon fetal size. Furthermore, studies demonstrate that a shift in fetal redox status consequent to environmental cues persists after birth and drives the progression of vascular dysfunction and hypertension in postnatal life. TLR (Toll-like receptor) signalling has emerged as a key link between inflammation and oxidative stress and a pathogenic contributor to hypertension, insulin resistance and obesity, in both human patients and animal models of disease. Thus TLR activation and dysregulation of its signalling components represent potential molecular underpinnings of programmed hypertension and related disorders in those subjected to suboptimal intrauterine conditions, yet their contributions to developmental programming remain unexplored. We propose that danger signals mobilized by the placenta or fetal tissues during complicated pregnancy activate the fetal innate immune system through TLRs and thereby potentiate the generation of ROS (reactive oxygen species) and orchestrate fetal adaptive responses, including changes in gene expression, which later translate to vascular dysfunction. Furthermore, we suggest that, after birth, continual activation of TLR signalling propagates vascular oxidative stress and thereby accelerates the advancement of hypertension and heart failure.

  19. Lack of Association between Toll Like Receptor-2 and Toll Like Receptor-4 Gene Polymorphisms and Other Feature in Iranian Asthmatics Patients.

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    Hamid Bahrami

    2015-02-01

    Full Text Available Asthma as a chronic inflammatory airway disease is considered to be the most common chronic disease that is involving genetic and environmental factors. Toll like receptors (TLRs and other inflammatory mediators are important in modulation of inflammation. In this study, we evaluated the role of TLR2 Arg753Gln and TLR4 Asp299Gly polymorphisms in the asthma susceptibility, progress, control levels and lung functions in Iranian patients. On 99 asthmatic patients and 120 normal subjects, TLR2 Arg753Gln and TLR4 Asp299Gly polymorphisms were evaluated by PCR-RFLP method recruiting Msp1 and Nco1 restriction enzymes, respectively. IgE serum levels by ELISA technique were determined and asthma diagnosis, treatment and control levels were considered using standard schemes and criteria. Our results indicated that the genotype and allele frequencies of the TLR2 Arg753Gln and TLR4 Asp299Gly polymorphisms were not significantly different between control subjects and asthmatics and were not related to in asthma features such as IgE levels, asthma history and pulmonary factors. Wherease some previous studies indicated TLRs and their polymorphisms might have some role in asthma incidence and features, our data demonstrated that TLR2 Arg753Gln and TLR4 Asp299Gly gene variants were not risk factors for asthma or its features in Iranian patients. Genetic complexity, ethnicity, influence of other genes or polymorphisms may overcome these polymorphisms in our asthmatics.

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

    Science.gov (United States)

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

    2017-01-16

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

  1. Role of Toll-Like Receptor 9 Signaling in Experimental Leishmania braziliensis Infection

    Science.gov (United States)

    Weinkopff, Tiffany; Mariotto, Anita; Simon, Gregoire; Hauyon-La Torre, Yazmin; Auderset, Floriane; Schuster, Steffen; Zangger, Haroun; Fasel, Nicolas; Barral, Aldina

    2013-01-01

    Infection with Leishmania braziliensis causes cutaneous or mucocutaneous leismaniasis in humans. Toll-like receptor 9 (TLR9) expression has been found in granulomas of lesions in L. braziliensis-infected individuals. L. braziliensis inoculation in mice induces very small lesions that are self-healing, whereas deficiency in the TLR adaptor molecule, MyD88, renders mice susceptible to infection. The TLR involved has not been identified, prompting us to investigate if TLR9 triggering by the parasite contributes to the strong resistance to infection observed in L. braziliensis-inoculated mice. The parasites activated wild-type (WT) dendritic cells (DCs) in vitro but not DCs derived from TLR9−/− mice. TLR9−/− mice inoculated with L. braziliensis exhibited a transient susceptibility characterized by increased lesion size and parasite burden compared to those of WT mice. Surprisingly, elevated levels of gamma interferon (IFN-γ) were measured at the site of infection and in draining lymph node T cells of TLR9−/− mice at the peak of susceptibility, suggesting that unlike observations in vitro, the parasite could induce DC activation leading to the development of Th1 cells in the absence of TLR9 expression. Taken together, these data show that TLR9 signaling is important for the early control of lesion development and parasite burden but is dispensable for the differentiation of Th1 cells secreting IFN-γ, and the high levels of this cytokine are not sufficient to control early parasite replication following L. braziliensis infection. PMID:23439309

  2. Synthetic Toll like receptor-4 (TLR-4 agonist peptides as a novel class of adjuvants.

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    Arulkumaran Shanmugam

    Full Text Available BACKGROUND: Adjuvants serve as catalysts of the innate immune response by initiating a localized site of inflammation that is mitigated by the interactions between antigens and toll like receptor (TLR proteins. Currently, the majority of vaccines are formulated with aluminum based adjuvants, which are associated with various side effects. In an effort to develop a new class of adjuvants, agonists of TLR proteins, such as bacterial products, would be natural candidates. Lipopolysaccharide (LPS, a major structural component of gram negative bacteria cell walls, induces the systemic inflammation observed in septic shock by interacting with TLR-4. The use of synthetic peptides of LPS or TLR-4 agonists, which mimic the interaction between TLR-4 and LPS, can potentially regulate cellular signal transduction pathways such that a localized inflammatory response is achieved similar to that generated by adjuvants. METHODOLOGY/PRINCIPAL FINDINGS: We report the identification and activity of several peptides isolated using phage display combinatorial peptide technology, which functionally mimicked LPS. The activity of the LPS-TLR-4 interaction was assessed by NF-κB nuclear translocation analyses in HEK-BLUE™-4 cells, a cell culture model that expresses only TLR-4, and the murine macrophage cell line, RAW264.7. Furthermore, the LPS peptide mimics were capable of inducing inflammatory cytokine secretion from RAW264.7 cells. Lastly, ELISA analysis of serum from vaccinated BALB/c mice revealed that the LPS peptide mimics act as a functional adjuvant. CONCLUSIONS/SIGNIFICANCE: Our data demonstrate the identification of synthetic peptides that mimic LPS by interacting with TLR-4. This LPS mimotope-TLR-4 interaction will allow for the development and use of these peptides as a new class of adjuvants, namely TLR-4 agonists.

  3. The Toll-Like receptor adaptor TRIF contributes to otitis media pathogenesis and recovery

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    Pak Kwang

    2009-08-01

    Full Text Available Abstract Background Toll-like receptor (TLR signalling is crucial for innate immune responses to infection. The involvement of TLRs in otitis media (OM, the most prevalent childhood disease in developed countries, has been implicated by studies in middle ear cell lines, by association studies of TLR-related gene polymorphisms, and by altered OM in mice bearing mutations in TLR genes. Activated TLRs signal via two alternative intracellular signaling molecules with differing effects; MyD88 (Myeloid differentiation primary response gene 88 inducing primarily interleukin expression and TRIF (Tir-domain-containing adaptor inducing interferon β mediating type I interferon (IFN expression. We tested the hypothesis that TRIF and type I IFN signaling play a role in OM, using a murine model of OM induced by non-typeable Haemophilus influenzae (NTHi. The ME inflammatory response to NTHi was examined in wild-type (WT and TRIF-/- mice by qPCR, gene microarray, histopathology and bacterial culture. Results Expression of TRIF mRNA was only modesty enhanced during OM, but both type I IFN signalling genes and type I IFN-inducible genes were significantly up-regulated in WT mice. TRIF-deficient mice showed reduced but more persistent mucosal hyperplasia and less leukocyte infiltration into the ME in response to NTHi infection than did WT animals. Viable bacteria could be cultured from MEs of TRIF-/- mice for much longer in the course of disease than was the case for middle ears of WT mice. Conclusion Our results demonstrate that activation of TRIF/type I IFN responses is important in both the pathogenesis and resolution of NTHi-induced OM.

  4. Leishmania pifanoi proteoglycolipid complex P8 induces macrophage cytokine production through Toll-like receptor 4.

    Science.gov (United States)

    Whitaker, Shanta M; Colmenares, Maria; Pestana, Karen Goldsmith; McMahon-Pratt, Diane

    2008-05-01

    The P8 proteoglycolipid complex (P8 PGLC) is a glyconjugate expressed by Leishmania mexicana complex parasites. We previously have shown that vaccination with P8 PGLC provides protection against cutaneous leishmaniasis in susceptible BALB/c mice. However, the biological importance of this complex remains unknown. Here we show that P8 PGLC localizes to the surface of Leishmania pifanoi amastigotes and that upon exposure to macrophages, P8 PGLC binds and induces inflammatory cytokine and chemokine mRNAs such as tumor necrosis factor alpha and RANTES early after stimulation. Our studies indicate that cytokine and chemokine induction is dependent upon Toll-like receptor 4 (TLR4). Interestingly, key inflammatory cytokines and chemokines (such as interleukin-6 [IL-6], macrophage inflammatory protein 1beta, and beta interferon [IFN-beta]) that can be induced through TLR4 activation were not induced or only slightly upregulated by P8 PGLC. Activation by P8 PGLC does not occur in the presence of TLR4 alone and requires both CD14 and myeloid differentiation protein 2 for signaling; this requirement may be responsible for the limited TLR4 response. This is the first characterization of a TLR4 ligand for Leishmania. In vitro experiments indicate that L. pifanoi amastigotes induce lower levels of cytokines in macrophages in the absence of TLR4; however, notably higher IL-10/IFN-gamma ratios were found for TLR4-deficient mice than for BALB/c mice. Further, increased levels of parasites persist in BALB/c mice deficient in TLR4. Taken together, these results suggest that TLR4 recognition of Leishmania pifanoi amastigotes is important for the control of infection and that this is mediated, in part, through the P8 PGLC.

  5. Protective effect of Toll-like receptor 4 in pulmonary vaccinia infection.

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    Martha A Hutchens

    Full Text Available Innate immune responses are essential for controlling poxvirus infection. The threat of a bioterrorist attack using Variola major, the smallpox virus, or zoonotic transmission of other poxviruses has renewed interest in understanding interactions between these viruses and their hosts. We recently determined that TLR3 regulates a detrimental innate immune response that enhances replication, morbidity, and mortality in mice in response to vaccinia virus, a model pathogen for studies of poxviruses. To further investigate Toll-like receptor signaling in vaccinia infection, we first focused on TRIF, the only known adapter protein for TLR3. Unexpectedly, bioluminescence imaging showed that mice lacking TRIF are more susceptible to vaccinia infection than wild-type mice. We then focused on TLR4, the other Toll-like receptor that signals through TRIF. Following respiratory infection with vaccinia, mice lacking TLR4 signaling had greater viral replication, hypothermia, and mortality than control animals. The mechanism of TLR4-mediated protection was not due to increased release of proinflammatory cytokines or changes in total numbers of immune cells recruited to the lung. Challenge of primary bone marrow macrophages isolated from TLR4 mutant and control mice suggested that TLR4 recognizes a viral ligand rather than an endogenous ligand. These data establish that TLR4 mediates a protective innate immune response against vaccinia virus, which informs development of new vaccines and therapeutic agents targeted against poxviruses.

  6. Toll-like receptor 3 increases allergic and irritant contact dermatitis.

    Science.gov (United States)

    Nakamura, Naomi; Tamagawa-Mineoka, Risa; Ueta, Mayumi; Kinoshita, Shigeru; Katoh, Norito

    2015-02-01

    There is increasing recognition of the role of Toll-like receptor 3 (TLR3) in noninfectious inflammatory diseases, but the function of TLR3 in inflammatory skin diseases is unclear. We investigated the functions of TLR3 in allergic and irritant contact dermatitis (ICD). The contact hypersensitivity (CHS) response was lower in Toll-like receptor 3 knockout (Tlr3 KO) mice, and was greater in TLR3 transgenic (Tg) mice than in wild-type (WT) mice after challenge with 2,4,6-trinitro-1-chlorobenzene. Adoptive transfer of immunized lymph node cells from Tlr3 KO mice induced CHS in WT recipients. In contrast, adoptive transfer of those from WT mice did not fully induce CHS in Tlr3 KO recipients. The ICD reaction following croton oil application was lower in Tlr3 KO mice, and was greater in TLR3 Tg mice than in WT mice. Maturation, migration, and antigen presentation of dendritic cells and proliferation of lymphocytes between WT mice and Tlr3 KO mice were comparable. These results show that TLR3 enhances antigen-independent skin inflammation in the elicitation phase of allergic contact dermatitis and in ICD.

  7. Quercetin modulates toll-like receptor-mediated protein kinase signaling pathways in oxLDL-challenged human PBMCs and regulates TLR-activated atherosclerotic inflammation in hypercholesterolemic rats.

    Science.gov (United States)

    Bhaskar, Shobha; Helen, A

    2016-12-01

    Toll-like receptors (TLRs) are pattern recognition receptors that have a unique and essential function in innate immunity. The effect of quercetin on TLR-mediated downstream signaling mechanism and its effect on TLR-mediated MAP kinase and Akt pathways were studied in oxLDL-stimulated hPBMCs using specific inhibitors. The pretreatment of hPBMCs with specific TLR inhibitor, CLI-095, decreased the NF-κB nuclear translocation and TNF-α release by oxLDL. When the cells treated with inhibitor and quercetin together, the inhibition was more effective. The specific inhibitor for p38 MAPK, SB203580, reduced the phosphorylated p38 level and decreased the NF-κB activation and TNF-α release by oxLDL-challenged hPBMCs. This inhibitor showed enhanced inhibition when treated with quercetin together. The inhibitors for ERK1/2, PD98059, and for JNK, SP606125, also showed inhibitory effect on NF-κB activation and TNF-α release by oxLDL-simulated hPBMCs. Quercetin supplementation enhanced the inhibition of nuclear translocation of NF-κB and the release of cytokines. TLR4 inhibition study confirmed the downstream signaling mechanism mediated by NF-κB which is involved in the oxLDL-induced inflammatory response, and quercetin suppresses the cytokine, TNF-α release by modulating TLR-NF-κB signaling pathway. In addition to NF-κB signaling pathway, inflammation induced by oxLDL was also related to the activation of p38MAPK, ERK1/2 and JNK, and Akt pathways, and the protective effect of quercetin may be also related to the inhibition of activation of these pathways. Quercetin significantly downregulated the elevated mRNA expression of TLRs and cytokine TNF-α in HCD-fed atherosclerotic rats in vivo. As quercetin possesses inhibition on both TLR-NF-κB signaling pathway and TLR-mediated MAPK pathway, it is evident that it can be used as a therapeutic agent to ameliorate atherosclerotic inflammation. Since quercetin is the major flavonoid and forms the backbone of many other

  8. Toll-like receptor-2 and -4 are associated with hyperlipidemia.

    Science.gov (United States)

    Zhu, Ya-Jun; Wang, Chao; Song, Guangyao; Zang, Sha-Sha; Liu, Yi-Xuan; Li, Ling

    2015-12-01

    Recent studies have suggested that toll-like receptors (TLRs) contribute to insulin resistance, and that fatty acids have a role in TLR activation. Other studies have found that TLR2 and TLR4 upregulation is consistent with an increase in serum lipid. Therefore, it was hypothesized that TLRs are associated with hyperlipidemia. The aim of the present study was to investigate whether TLR2 or TLR4 was associated with hyperlipidemia and to provide novel targets for hyperlipidemia therapy. Volunteers were selected at the Medical Examination Center of Hebei General Hospital (Shijiazhuang, China), including 43 patients with high triglyceride (TG) levels, 84 with high total cholesterol (TC) levels and 55 with high TG and high TC levels. In addition, 68 healthy volunteers were selected as a control group. For the animal study, the TLR gene and protein levels were assessed in the skeletal muscle of rats fed a high‑fat diet. As expected, TLR2 and TLR4 gene expression were upregulated when TC increased, TG increased, or TC and TG increased. In rats fed a high‑fat diet, the levels of gene and protein expression in the skeletal muscle of the two TLRs were all increased compared with the control group, this was consistent with an increase in TC and TG. In addition, in drug treatment groups the mRNA and protein expression levels of TLR in the skeletal muscle of rats fed a high fat diet were decreased, as were the TC and TG levels. In conclusion, these findings suggest that TLR2 and TLR4 are associated with hyperlipidemia.

  9. Toll-like receptor 4 D299G polymorphism in metabolic disorders: a meta-analysis.

    Science.gov (United States)

    Belforte, F S; Coluccio Leskow, F; Poskus, E; Penas Steinhardt, A

    2013-04-01

    The toll-like receptor 4 (TLR4) plays a key role in the activation of innate immune response participating in the recognition of lipopolysaccharides. Changes in the innate immune response are involved in the pathogenesis of some metabolic disorders such as metabolic syndrome and type 2 diabetes mellitus (Met-S and T2DM). It has been recently shown the role of gut microbiota in the perpetuation of both insulin resistance and low-grade chronic inflammation. Some studies have reported that TLR4 D299G polymorphism is associated with metabolic disorders, however results have been inconsistent. Two recent meta-analyses showed that D299G is associated with inflammatory bowel disease and gastrointestinal cancers risk, two pathological states in which the luminal microbial flora-host cells interaction may be implicated. We conducted a systemic review of the published data considering all eligible published studies (six studies with 1696 cases and 3388 controls for D299G) and a meta-analysis was performed to evaluate the association between TLR4 D299G polymorphism and the risk for metabolic disorders. Five studies were identified for T2DM: three corresponding to Caucasian populations and two to mixed populations. The remaining study analyzed Met-S in a Caucasian population. We observed a significant association between D299G polymorphism and metabolic disorders (T2DM and Met-S) risk (OR = 0.566, 95 % CI: 0.347-0.925, p = 0.023) particularly in Caucasians. No association was found in mixed population subgroup. Our meta-analysis identified that the AG/GG genotypes of D299G are associated with decreased metabolic disorders risk.

  10. Toll-like receptor 4 contributes to acute kidney injury after cardiopulmonary resuscitation in mice

    Science.gov (United States)

    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

  11. Herpes simplex virus induces neural oxidative damage via microglial cell Toll-like receptor-2

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    Little Morgan R

    2010-06-01

    Full Text Available Abstract Background Using a murine model of herpes simplex virus (HSV-1 encephalitis, our laboratory has determined that induction of proinflammatory mediators in response to viral infection is largely mediated through a Toll-like receptor-2 (TLR2-dependent mechanism. Published studies have shown that, like other inflammatory mediators, reactive oxygen species (ROS are generated during viral brain infection. It is increasingly clear that ROS are responsible for facilitating secondary tissue damage during central nervous system infection and may contribute to neurotoxicity associated with herpes encephalitis. Methods Purified microglial cell and mixed neural cell cultures were prepared from C57B/6 and TLR2-/- mice. Intracellular ROS production in cultured murine microglia was measured via 2', 7'-Dichlorofluorescin diacetate (DCFH-DA oxidation. An assay for 8-isoprostane, a marker of lipid peroxidation, was utilized to measure free radical-associated cellular damage. Mixed neural cultures obtained from β-actin promoter-luciferase transgenic mice were used to detect neurotoxicity induced by HSV-infected microglia. Results Stimulation with HSV-1 elevated intracellular ROS in wild-type microglial cell cultures, while TLR2-/- microglia displayed delayed and attenuated ROS production following viral infection. HSV-infected TLR2-/- microglia produced less neuronal oxidative damage to mixed neural cell cultures in comparison to HSV-infected wild-type microglia. Further, HSV-infected TLR2-/- microglia were found to be less cytotoxic to cultured neurons compared to HSV-infected wild-type microglia. These effects were associated with decreased activation of p38 MAPK and p42/p44 ERK in TLR2-/- mice. Conclusions These studies demonstrate the importance of microglial cell TLR2 in inducing oxidative stress and neuronal damage in response to viral infection.

  12. Toll-like receptor modulation in cardiovascular disease: a target for intervention?

    Science.gov (United States)

    Földes, Gábor; von Haehling, Stephan; Anker, Stefan D

    2006-08-01

    Toll-like receptors (TLRs) form a family of pattern recognition receptors that have emerged as key mediators of innate immunity. These receptors sense invading microbes and initiate the immune response. TLR-mediated inflammation is an important pathogenic link between innate immunity and a diverse panel of clinical disorders. Among the processes in which TLRs play a role are cardiovascular disorders such as cardiac ischaemia, coronary artery disease, ventricular remodelling, cancer angiogenesis or transplant rejection. From these, many important opportunities for disease modification through TLR signalling manipulation can be imagined. Their role as potential targets for therapeutic intervention is just beginning to be appreciated and this article reviews the current status of these treatment strategies for cardiovascular disease.

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

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    Robert G Schaut

    Full Text Available 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.

  14. T cells induce extended class II MHC compartments in dendritic cells in a Toll-like receptor-dependent manner.

    Science.gov (United States)

    Boes, Marianne; Bertho, Nicolas; Cerny, Jan; Op den Brouw, Marjolein; Kirchhausen, Tomas; Ploegh, Hidde

    2003-10-15

    Interaction of Ag-loaded dendritic cells with Ag-specific CD4 T cells induces the formation of long tubular class II MHC-positive compartments that polarize toward the T cell. We show involvement of a Toll-like receptor-mediated signal in this unusual form of intracellular class II MHC trafficking. First, wild-type dendritic cells loaded with LPS-free Ag failed to show formation of class II-positive tubules upon Ag-specific T cell engagement, but did so upon supplementation of the Ag with low concentrations of LPS. Second, Ag-loaded myeloid differentiation factor 88 -deficient dendritic cells failed to form these tubules upon interaction with T cells, regardless of the presence of LPS. Finally, inclusion of a cell-permeable peptide that blocks TNFR-associated factor 6 function, downstream of myeloid differentiation factor 88, blocked T cell-dependent tubulation. A Toll-like receptor-dependent signal is thus required to allow Ag-loaded dendritic cells to respond to T cell contact by formation of extended endosomal compartments. This activation does not result in massive translocation of class II MHC molecules to the cell surface.

  15. Application potential of toll-like receptors in cancer immunotherapy: Systematic review.

    Science.gov (United States)

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

    2016-06-01

    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 evaluated

  16. Immunomodulation by Gut Microbiota: Role of Toll-Like Receptor Expressed by T Cells

    Directory of Open Access Journals (Sweden)

    Mariagrazia Valentini

    2014-01-01

    Full Text Available A close relationship exists between gut microbiota and immune responses. An imbalance of this relationship can determine local and systemic immune diseases. In fact the immune system plays an essential role in maintaining the homeostasis with the microbiota that normally resides in the gut, while, at the same time, the gut microbiota influences the immune system, modulating number and function of effector and regulatory T cells. To achieve this aim, mutual regulation between immune system and microbiota is achieved through several mechanisms, including the engagement of toll-like receptors (TLRs, pathogen-specific receptors expressed on numerous cell types. TLRs are able to recognize ligands from commensal or pathogen microbiota to maintain the tolerance or trigger the immune response. In this review, we summarize the latest evidences about the role of TLRs expressed in adaptive T cells, to understand how the immune system promotes intestinal homeostasis, fights invasion by pathogens, and is modulated by the intestinal microbiota.

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

    Science.gov (United States)

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

    2015-10-01

    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.

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

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    Bryan E. Hart

    2012-01-01

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

  19. The Battle between Virus and Host: Modulation of Toll-Like Receptor Signaling Pathways by Virus Infection

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    Shin-ichi Yokota

    2010-01-01

    Full Text Available In order to establish an infection, viruses need to either suppress or escape from host immune defense systems. Recent immunological research has focused on innate immunity as the first line of host defense, especially pattern recognition molecules such as Toll-like receptors (TLRs, RIG-I-like receptors (RLRs, and NOD-like receptors (NLRs. Various microbial components are recognized by their vague and common molecular shapes so-called, pathogen-associated molecular patterns (PAMPs. PAMPs induce inflammatory reactions mediated by the activation of the transcription factor, NF-B, and by interferons, which lead to an antiviral immune response. Viruses have the capacity to suppress or escape from this pattern recognition molecule-mediated antimicrobial response in various ways. In this paper, we review the various strategies used by viruses to modulate the pattern recognition molecule-mediated innate immune response.

  20. Acute ethanol administration inhibits Toll-like receptor 4 signaling pathway in rat intestinal epithelia.

    Science.gov (United States)

    Zhou, Chao; Zhao, Ji; Li, Jing; Wang, Haiying; Tang, Chengwei

    2013-05-01

    Excess alcohol intake, as in binge drinking, increases susceptibility to microbial pathogens. Alcohol impairs macrophage function by suppression of the Toll-like receptor 4 (TLR4) pathway. This study investigated the effects of acute ethanol intake on the TLR4 pathway in rat intestinal epithelia, which usually encounters luminal antigens at first and participates in the development of intestinal immunity. Twenty Wistar rats were randomly assigned to an ethanol group given ethanol as a 25% (v/v) solution in water at 7.5 g/kg, or a control group given saline, by oral gavage daily for 3 days. The epithelial histology and ultrastructure, the intestinal microflora, peripheral and portal venous plasma lipopolysaccharide (LPS) levels, and somatostatin (SST) levels in the peripheral plasma and small intestine were evaluated. Somatostatin receptor 2 (SSTR2), TLR4, TANK binding kinase-1 (TBK1), activated nuclear factor-κB (NF-κB), interferon-γ (IFN-γ) and tumor necrosis factor-α (TNF-α) in the intestinal mucosa were assayed. LPS responsiveness with or without SST pretreatment was assayed in vitro by quantification of TLR4, TBK1, activated NF-κB, IFN-γ and TNF-α in isolated intestinal epithelia. Mucosal damage was observed in the ethanol group by light and electron microscopy. Escherichia coli cultures were unchanged in rat intestine of the ethanol group compared with controls, but lactobacilli cultures were reduced (p TNF-α were unchanged in the ethanol group. LPS treatment in vitro up-regulated the level of TLR4, TBK1 and nuclear NF-κB as well as the production of IFN-γ and TNF-α in isolated intestinal epithelia in the control (p inhibited by SST pretreatment (p < 0.05). The peripheral plasma and intestinal levels of SST and the mucosal expression of SSTR2 in the ethanol group were significantly higher than in the control group (p < 0.05). These findings suggest the hyposensitivity of intestinal epithelial TLR4 to LPS induced by acute alcohol abuse

  1. DMPD: Inhibition of toll-like receptor and cytokine signaling--a unifying theme inischemic tolerance. [Dynamic Macrophage Pathway CSML Database

    Lifescience Database Archive (English)

    Full Text Available 15545925 Inhibition of toll-like receptor and cytokine signaling--a unifying theme ...png) (.svg) (.html) (.csml) Show Inhibition of toll-like receptor and cytokine signaling--a unifying theme i...nischemic tolerance. PubmedID 15545925 Title Inhibition of toll-like receptor and... cytokine signaling--a unifying theme inischemic tolerance. Authors Kariko K, Weissman D, Welsh FA. Publicat

  2. Toll-like receptors expressed by dermal fibroblasts contribute to hypertrophic scarring.

    Science.gov (United States)

    Wang, JianFei; Hori, Keijiro; Ding, Jie; Huang, Yue; Kwan, Peter; Ladak, Adil; Tredget, Edward E

    2011-05-01

    Hypertrophic scar (HTS), a fibroproliferative disorder (FPD), complicates burn wound healing. Although the pathogenesis is not understood, prolonged inflammation is a known contributing factor. Emerging evidence suggests that fibroblasts regulate immune/inflammatory responses through toll-like receptor 4 (TLR4) activated by lipopolysaccharide (LPS) through adaptor molecules, leading to nuclear factor kappa-light-chain-enhancer of activated B cells and mitogen-activated protein kinases activation, cytokine gene transcription and co-stimulatory molecule expression resulting in inflammation. This study explored the possible role of TLR4 in HTS formation. Paired normal and HTS tissue from burn patients was collected and dermal fibroblasts isolated and cultured. Immunohistochemical analysis of tissues demonstrated increased TLR4 staining in HTS tissue. Quantitative RT-PCR of three pairs of fibroblasts demonstrated mRNA levels for TLR4 and its legend myeloid differentiation factor 88 (MyD88) in HTS fibroblasts were increased significantly compared with normal fibroblasts. Flow cytometry showed increased TLR4 expression in HTS fibroblasts compared with normal. ELISA demonstrated protein levels for prostaglandin E2, interleukin (IL)-6, IL-8 and monocyte chemotactic protein-1 (MCP-1) were significantly increased in HTS fibroblasts compared to normal. When paired normal and HTS fibroblasts were stimulated with LPS, significant increases in mRNA and protein levels for MyD88, IL-6, IL-8, and MCP-1 were detected. However, when transfected with MyD88 small interfering RNA (siRNA), then stimulated with LPS, a significant decrease in mRNA and protein levels for these molecules compared to only LPS-stimulated fibroblasts was detected. In comparison, a scramble siRNA transfection did not affect mRNA or protein levels for these molecules. Results demonstrate LPS stimulates proinflammatory cytokine expression in dermal fibroblasts and MyD88 siRNA eliminates the expression. Therefore

  3. Control of hepatitis B virus replication by interferons and Toll-like receptor signaling pathways.

    Science.gov (United States)

    Pei, Rong-Juan; Chen, Xin-Wen; Lu, Meng-Ji

    2014-09-07

    Hepatitis B virus (HBV) infection is one of the major causes of liver diseases, affecting more than 350 million people worldwide. The interferon (IFN)-mediated innate immune responses could restrict HBV replication at the different steps of viral life cycle. Indeed, IFN-α has been successfully used for treatment of patients with chronic hepatitis B. However, the role of the innate immune response in HBV replication and the mechanism of the anti-HBV effect of IFN-α are not completely explored. In this review, we summarized the currently available knowledge about the IFN-mediated anti-HBV effect in the HBV life cycle and the possible effectors downstream the IFN signaling pathway. The antiviral effect of Toll-like receptors (TLRs) in HBV replication is briefly discussed. The strategies exploited by HBV to evade the IFN- and TLR-mediated antiviral actions are summarized.

  4. Do you see what I see: Recognition of protozoan parasites by Toll-like receptors.

    Science.gov (United States)

    Ghosh, Debopam; Stumhofer, Jason S

    2013-08-01

    Toll-like receptors (TLRs) are important for recognizing a variety of pathogens, including protozoan parasites, and initiating innate immune responses against them. TLRs are localized on the cell surface as well as in the endosome, and are implicated in innate sensing of these parasites. In this review, we will discuss recent findings on the identification of parasite-derived pathogen associated molecular patterns and the TLRs that bind them. The role of these TLRs in initiating the immune response against protozoan parasitic infections in vivo will be presented in the context of murine models of infection utilizing TLR-deficient mice. Additionally, we will explore evidence that TLRs and genetic variants of TLRs may impact the outcome of these parasitic infections in humans.

  5. Sequence analysis of the Toll-like receptor 2 gene of old world camels

    Directory of Open Access Journals (Sweden)

    Shyam S. Dahiya

    2014-11-01

    Full Text Available The Toll-like receptor 2 (TLR2 gene of old world camels (Camelus dromedarius and Camelus bactrianus was cloned and sequenced. The TLR2 gene of the dromedary camel had the highest nucleotide and amino acid identity with pig, i.e., 66.8% and 59.6%, respectively. Similarly, the TLR2 gene of the Bactrian camel also had the highest nucleotide and amino acid identity with pig, i.e., 85.7% and 81.4%, respectively. Dromedary and Bactrian camels shared 77.9% nucleotide and 73.6% amino acid identity with each other. Interestingly, the amidation motif is present in camel (Dromedary and Bactrian TLR2 only, and the TIR domain is absent in Dromedary camel TLR2. This is the first report of the TLR2 gene sequence of Dromedary and Bactrian camels.

  6. Toll-like receptor 3 regulates neural stem cell proliferation by modulating the Sonic Hedgehog pathway.

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    Kavitha Yaddanapudi

    Full Text Available Toll-like receptor 3 (TLR3 signaling has been implicated in neural stem/precursor cell (NPC proliferation. However, the molecular mechanisms involved, and their relationship to classical TLR-mediated innate immune pathways, remain unknown. Here, we report investigation of the mechanics of TLR3 signaling in neurospheres comprised of epidermal growth factor (EGF-responsive NPC isolated from murine embryonic cerebral cortex of C57BL/6 (WT or TLR3 deficient (TLR3(-/- mice. Our data indicate that the TLR3 ligand polyinosinic-polycytidylic acid (PIC negatively regulates NPC proliferation by inhibiting Sonic Hedgehog (Shh signaling, that PIC induces apoptosis in association with inhibition of Ras-ERK signaling and elevated expression of Fas, and that these effects are TLR3-dependent, suggesting convergent signaling between the Shh and TLR3 pathways.

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

    Science.gov (United States)

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

    Science.gov (United States)

    Chen, Luxi; Yu, Jianhua

    2016-08-01

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

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

    Science.gov (United States)

    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.

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

    NARCIS (Netherlands)

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

    2012-01-01

    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 m

  11. Toll Like Receptor 4 Affects the Cerebral Biochemical Changes Induced by MPTP Treatment.

    Science.gov (United States)

    Conte, Carmela; Roscini, Luca; Sardella, Roccaldo; Mariucci, Giuseppina; Scorzoni, Stefania; Beccari, Tommaso; Corte, Laura

    2017-01-21

    The etiology and pathogenesis of Parkinson's disease (PD) are still unclear. However, multiple lines of evidence suggest a critical role of the toll like receptor 4 (TLR4) in inflammatory response and neuronal death. Neuroinflammation may be associated with the misfolding and aggregation of proteins accompanied by a change in their secondary structure. Recent findings also suggest that biochemical perturbations in cerebral lipid content could contribute to the pathogenesis of central nervous system (CNS) disorders, including PD. Thus, it is of great importance to determine the biochemical changes that occur in PD. In this respect, Fourier Transform Infrared (FTIR) spectroscopy represents a useful tool to detect molecular alterations in biological systems in response to stress stimuli. By relying upon FTIR approach, this study was designed to elucidate the potential role of TLR4 in biochemical changes induced by methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) neurotoxin in a mouse model of PD. The analysis of the FTIR spectra was performed in different brain regions of both wild type (WT) and toll like receptor 4-deficient (TLR4(-/-)) mice. It revealed that each brain region exhibited a characteristic molecular fingerprint at baseline, with no significant differences between genotypes. Conversely, WT and TLR4(-/-) mice showed differential biochemical response to MPTP toxicity, principally related to lipid and protein composition. These differences appeared to be characteristic for each brain area. Furthermore, the present study showed that WT mice resulted more vulnerable than TLR4(-/-) animals to striatal dopamine (DA) depletion following MPTP treatment. These results support the hypothesis of a possible involvement of TLR4 in biochemical changes occurring in neurodegeneration.

  12. microRNA-26a modulates inflammatory response induced by toll-like receptor 4 stimulation in microglia.

    Science.gov (United States)

    Kumar, Asit; Bhatia, Harsharan Singh; de Oliveira, Antonio Carlos Pinheiro; Fiebich, Bernd L

    2015-12-01

    MiRNAs, a family of small non-coding RNAs, have emerged as novel post-transcriptional regulators of numerous cellular responses. Although the involvement of miRNAs in the regulation of neuroinflammation in various neurological diseases has been previously studied, their role in the production of inflammatory mediators during microglia activation is poorly understood. In this study, the role of miR-26a has been investigated in the modulation of inflammatory response in cultured microglia. Using real-time PCR, the expression of miR-26a was studied in toll-like receptors 4 stimulated primary mouse microglia. miR-26a expression was found to be rapidly reduced after the stimulation of toll-like receptors 4 in microglia. Over-expression of miR-26a significantly decreased the production of inflammatory cytokines such as tumor necrosis factor α and IL-6, whereas knockdown of miR-26a increased the expression of these mediators. Furthermore, using in silico analysis, we identified that the activating transcription factor (ATF) 2 is directly targeted by miR-26a. This finding was confirmed by loss and gain of function studies. Similar to the effect of miR-26a over-expression, knockdown of activating transcription factor 2 inhibited the production of proinflammatory cytokines, particularly IL-6. Taken together, our results suggest the involvement of miR-26a in the regulation of the production of proinflammatory cytokines in microglia. We proposed that in microglia, activation of toll-like receptor 4 (TLR4) by lipopolysaccharide (LPS) down-regulates miR-26a. The down-regulation of this miR increases expression of activating transcription factor 2 (ATF2). This event, in addition to the activation of ATF2 by c-Jun N-terminal kinase (JNK), increases interleukin-6 (IL-6) production. On the other hand, miR-26a also increases the production of tumor necrosis factor α (TNFα) by a mechanism independent of ATF2.

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

    Science.gov (United States)

    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

  14. Upregulated functional expression of Toll like receptor 4 in mesenchymal stem cells induced by lipopolysaccharide

    Institute of Scientific and Technical Information of China (English)

    SHI Liang; WANG Ji-shi; LIU Xing-mei; HU Xiao-yan; FANG Qin

    2007-01-01

    Background The coordinated change of haematopoietic supporting microenvironment in bone marrow (BM) is crucial for innate immunity and inflammation. As the precursors of marrow stroma, BM derived mesenchymal stem cells (MSCs)promote haematopoietic function, but their roles in innate immunity or inflammation have not been investigated. Here we investigated the expression of Toll like receptor 4 (TLR-4) and the effect of lipopolysaccharide (LPS) on its expression in BM MSCs in vitro.Methods MSCs were harvested from adult rat's BM cells by density gradient centrifugation and adhesive culture. The purity of MSCs were identified with the cell morphological feature and osteogenic capacity, the phenotypes were tested by flow cytometry. Cultured MSCs were treated by LPS (1 μg/ml, 10 μg/ml or 100 μg/ml) for 24 hours. The relative expression levels of TLR-4 mRNA were detected by semiquantitative reverse transcription polymerase chain reaction and costimulatory molecules (CD80, CD86 and MHC-Ⅱ) expressed on MSCs were analyzed by flow cytometry. The levels of tumor necrosis factor-α (TNF-α) in supernatants were determined by enzyme linked immunosorbent assay.Results After incubation with LPS, MSCs expressed the higher levels of TLR-4 mRNA, costimulatory molecules and TNF-α than the untreated group: LPS 10 μg/ml was the most effective (P<0.01); the levels of TLR-4 mRNA, costimulatory molecules and TNF-α decreased when MSCs were exposed to 100 μg/ml LPS. Except for MHC-Ⅱ and TNF-α (P>0.05),the levels of CD80, CD86 and TLR-4 mRNA were significantly lower than that in the treated group of 10 μg/ml (P<0.01).Conclusion MSCs expressed TLR-4 mRNA. LPS activated the functional expression levels of TLR-4 in MSCs although the activity may depend on the concentration of LPS.

  15. Antagonists of toll like receptor 4 maybe a new strategy to counteract opioid-induced hyperalgesia and opioid tolerance.

    Science.gov (United States)

    Li, Qian

    2012-12-01

    Long term opioid treatment results in hyperalgesia and tolerance, which is a troublesome phenomenon in clinic application. Recent studies have revealed a critical role of toll-like receptor 4 (TLR4) in the neuropathological process of opioid-induced hyperalgesia and tolerance. TLR4 is predominantly expressed by microglial cells and is a key modulator in the activation of the innate immune system. Activation of TLR4 may initiate the activation of microglia and hence a number of neurotransmitters and neuromodulators that could enhance neuronal excitability are released. Blockade of TLR4 activation by its antagonists alleviate neuropathic pain. We hypothesized that opioid antagonists such as naloxone and naltrexone, which were also demonstrated to be TLR4 antagonist, may have clinic application value in attenuation of opioid-induced hyperalgesia and tolerance.

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

    Science.gov (United States)

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

    2016-01-07

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

  17. Toll-like receptor 4/nuclear factor-kappa B signaling detected in brain after early subarachnoid hemorrhage

    Institute of Scientific and Technical Information of China (English)

    MA Chun-xiao; YIN Wei-ning; CAI Bo-wen; WU Jian; WANG Jun-yi; HE Min; SUN Hong; DING Jun-li; YOU Chao

    2009-01-01

    Background Inflammation and immunity play a vital role in the pathogenesis of early brain injury after subarachnoid hemorrhage (SAH). Nuclear factor-kappa B (NF-KB) regulates many genes essential for inflammation and immunity and is activated by toll-like receptor (TLR). This study aimed to detect the expression of the toll-like receptor 4/nuclear factor-kappa B (TLR4/NF-KB) signaling in the rat brain after early SAH. Methods The rats were decapitated and their brains were removed at 0, 2, 4, 6, 12, 24 and 48 hours after a single injection of blood into the prechiasmatic cistern, mRNA expression of TLR4 was measured by Taqman real-time RT-PCR, and protein expression by immunohistochemistry and Western blotting. NF-KB activity and concentrations of tumor necrosis factor-alpha (TNF-α), interleukin-lbeta (IL-β) and intedeukin-6 (IL-6) were measured by enzyme-linked immunosorbent assay (ELISA).Results TaqMan real-time RT-PCR and Western blotting identified a biphasic change in TLR4 expression in both mRNA and protein: an initial peak (2-6 hours) and a sustained elevation (12-48 hours). Immunohistochemical staining showed the inducible expression of TLR4-1ike immunoreactions predominantly in glial cells and vascular endothelium. A similar biphasic change in the activation of NF-KB subunit p65 as well as the production of NF-KB-regulated proinflammatory cytokines (TNF-α, IL-1β and IL-6) were detected by ELISA. Conclusions These data suggest that experimental SAH induces significant up-regulation of TLR4 expression and the NF-KB signaling in early brain injury. Activation of the TLR4/NF-KB signaling may regulate the inflammatory responses after SAH.

  18. Toll-like receptor 2 suppresses immunity against Candida albicans through induction of IL-10 and regulatory T cells.

    NARCIS (Netherlands)

    Netea, M.G.; Sutmuller, R.P.M.; Hermann, C.; Graaf, C.A.A. van der; Meer, J.W.M. van der; Krieken, J.H.J.M. van; Hartung, T.; Adema, G.J.; Kullberg, B.J.

    2004-01-01

    Toll-like receptor (TLR) 2 and TLR4 play a pivotal role in recognition of Candida albicans. We demonstrate that TLR2(-/-) mice are more resistant to disseminated Candida infection, and this is associated with increased chemotaxis and enhanced candidacidal capacity of TLR2(-/-) macrophages. Although

  19. Genetic Variation in TLR10, an Inhibitory Toll-Like Receptor, Influences Susceptibility to Complicated Skin and Skin Structure Infections.

    NARCIS (Netherlands)

    Stappers, M.H.T.; Oosting, M.; Ioana, M.; Reimnitz, P.; Mouton, J.W.; Netea, M.G.; Gyssens, I.C.J.; Joosten, L.A.B.

    2015-01-01

    BACKGROUND: Toll-like receptors (TLRs) play a central role in the innate immune response to complicated skin and skin structure infections (cSSSIs), with TLR10 being the first family member known to have an inhibitory function. This study assessed the role of TLR10 in recognition of cSSSI-related pa

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

    Science.gov (United States)

    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...

  1. Tendon degeneration is not mediated by regulation of Toll-like receptors 2 and 4 in human tenocytes.

    NARCIS (Netherlands)

    Mos, M. de; Joosten, L.A.B.; Oppers-Walgreen, B.; Schie, J.T. van; Jahr, H.; Osch, G.J.V.M. van; Verhaar, J.A.N.

    2009-01-01

    We hypothesized that expression of Toll-like receptors (TLRs) 2 and 4 by tenocytes is involved in the catabolic processes of tendon degeneration. We investigated TLR2 and TLR4 expression by tenocytes in healthy and tendinotic Achilles tendons. We also investigated whether TLR2 and TLR4 could be upre

  2. Expression of Toll-like receptor 9 and response to bacterial CpG oligodeoxynucleotides in human intestinal epithelium

    DEFF Research Database (Denmark)

    Pedersen, G; Andresen, Lars; Matthiessen, M W

    2005-01-01

    Recognition of repeat CpG motifs, which are common in bacterial, but not in mammalian, DNA, through Toll-like receptor (TLR)9 is an integral part of the innate immune system. As the role of TLR9 in the human gut is unknown, we determined the spectrum of TLR9 expression in normal and inflamed colo...

  3. Association of Toll-like receptor 2 Arg753Gln and Toll-like receptor 1 Ile602Ser single-nucleotide polymorphisms with leptospirosis in an Argentine population.

    Science.gov (United States)

    Cédola, Maia; Chiani, Yosena; Pretre, Gabriela; Alberdi, Lucrecia; Vanasco, Bibiana; Gómez, Ricardo M

    2015-06-01

    Toll-like receptor 2 (TLR2), a member of the Toll-like receptor family, plays an important role in the recognition of and subsequent immune response activation against leptospirosis in humans. The genetic polymorphism in TLR2 of an arginine to glutamine substitution at residue 753 (Arg753Gln) has been associated with a negative influence on TLR2 function, which may, in turn, determine the innate host response to Leptospira spp. This bacterium signals through TLR2/TLR1 heterodimers in human cells. The aim of the present study was to investigate the Arg753Gln single-nucleotide polymorphism (SNP) of the TLR2 gene, and the isoleucine to serine transversion at position 602 (Ile602Ser) of the TLR1 gene (previously associated with Lyme disease), in leptospirosis patients compared to healthy controls, carrying out a retrospective case/control study. The TLR2 polymorphism adenine (A) allele was observed in 7.3% of leptospirosis patients but was not found in the control group, whereas the guanine (G) allele of the TLR1 polymorphism was found in 63.6% of patients and 41.6% of controls. Susceptibility to leptospirosis disease was increased 10.57-fold for carriers of the TLR2 G/A genotype (P=0.0493) and 3.85-fold for carriers of the TLR1 G/G genotype (P=0.0428). Furthermore, the risk of developing hepatic insufficiency and jaundice was increased 18.86- and 27.60-fold for TLR2 G/A carriers, respectively. Similarly, the risk of developing jaundice was increased 12.67-fold for TLR1 G allele carriers (G/G and T/G genotypes). In conclusion, the present data suggest that the TLR2 Arg753Gln and TLR1 Ile602Ser SNPs influence the risk of developing leptospirosis and its severity.

  4. Endothelial cell Toll-like receptor 4 regulates fibrosis associated angiogenesis in liver

    Science.gov (United States)

    Jagavelu, K; Routray, C; Shergill, U; O’Hara, SP; Faubion, W; Shah, VH

    2010-01-01

    Angiogenesis defines the growth of new blood vessels from pre-existing vascular endothelial networks and corresponds with the wound healing process that is typified by the process of liver fibrosis. Liver fibrosis is also associated with increased endotoxin within the gut lumen and its associated portal circulation. However, the interrelationship of gut endotoxin and its receptor, Toll-like receptor 4 (TLR4), with liver fibrosis and associated angiogenesis remains incompletely defined. RESULT Here we provide evidence, using complementary genetic, molecular, and pharmacologic approaches that the pattern recognition receptor that recognizes endotoxin, TLR4, expressed on liver endothelial cells (LEC), regulates angiogenic responses both in vitro and in vivo. Mechanistic studies reveal a key role for a cognate TLR4 effector protein, MyD88 in this process which culminates in extracellular protease production that regulates LEC invasive capacity, a key step in angiogenesis. Furthermore TLR4 dependent angiogenesis in vivo corresponds with fibrosis in complementary liver models of fibrosis. CONCLUSION These studies provide evidence that the TLR4 pathway in LEC regulates angiogenesis through its MyD88 effector protein by regulating extracellular protease production and that this process is linked to the development of liver fibrosis. PMID:20564354

  5. Intrathecal siRNA against Toll-like receptor 4 reduces nociception in a rat model of neuropathic pain

    Directory of Open Access Journals (Sweden)

    Fei-xiang Wu, Jin-jun Bian, Xue-rong Miao, Sheng-dong Huang, Xue-wu Xu, De-jun Gong, Yu-ming Sun, Zhi-jie Lu, Wei-feng Yu

    2010-01-01

    Full Text Available Background: Neuropathic pain is characterized by hyperalgesia, allodynia and spontaneous pain. It often occurs as a result of injury to peripheral nerves, dorsal root ganglions (DRG, spinal cord, or brain. Recent studies have suggested that Toll-like receptor 4 (TLR4 might play a role in neuropathic pain. Methodology/Principal Findings: In this study, we investigated the role of TLR4 in a rat chronic constriction injury (CCI model and explored the feasibility of treating neuropathic pain by inhibiting TLR4. Our results demonstrated that intrathecal siRNA-mediated suppression of TLR4 attenuated CCI-induced mechanical allodynia and thermal hyperalgesia through inhibiting the activation of NF-κB p65 and production of proinflammatory cytokines (e.g., TNF-α and IL-1β. Conclusions/Significance: These findings suggest that suppression of TLR4 mediated by intrathecally administered siRNA may be a new strategy for the treatment of neuropathic pain.

  6. Toll-like receptors as a key regulator of mesenchymal stem cell function: An up-to-date review.

    Science.gov (United States)

    Shirjang, Solmaz; Mansoori, Behzad; Solali, Saeed; Hagh, Majid Farshdousti; Shamsasenjan, Karim

    2016-12-26

    Understanding the role of toll-like receptors (TLRs) in the immunomodulation potential, differentiation, migration, and survival of mesenchymal stem cells (MSCs) is absolutely vital to fully exploiting their MSC-based therapeutic potential. Furthermore, through recognition of exogenous or endogenous ligands produced upon injury, TLRs have been linked to allograft rejection and maintenance of chronic inflammatory diseases, including Crohn's disease, rheumatoid arthritis. Characterizing the effect of TLRs in biological control of MSCs fate and function could improve our knowledge about the MSC-based cell therapy and immunotherapy. In this paper, we outline the impacts of TLR activation and mechanisms on MSCs immunomodulatory functions, differentiation, migration, and survivability. Moreover, we indicate that the expression patterns of TLRs in MSCs from different sources.

  7. DMPD: Toll-like receptors and the host defense against microbial pathogens: bringingspecificity to the innate-immune system. [Dynamic Macrophage Pathway CSML Database

    Lifescience Database Archive (English)

    Full Text Available 15075354 Toll-like receptors and the host defense against microbial pathogens: brin... the host defense against microbial pathogens: bringingspecificity to the innate-...immune system. PubmedID 15075354 Title Toll-like receptors and the host defense against microbial pathogens:

  8. Toll-Like Receptor 4 Wild Type Homozygozity of Polymorphisms +896 and +1196 Is Associated with High Gastrin Serum Levels and Peptic Ulcer Risk.

    Directory of Open Access Journals (Sweden)

    Vesa-Matti Pohjanen

    Full Text Available 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.

  9. Toll-Like Receptor 4 Wild Type Homozygozity of Polymorphisms +896 and +1196 Is Associated with High Gastrin Serum Levels and Peptic Ulcer Risk

    Science.gov (United States)

    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

  10. Toll-Like Receptor 4 Wild Type Homozygozity of Polymorphisms +896 and +1196 Is Associated with High Gastrin Serum Levels and Peptic Ulcer Risk.

    Science.gov (United States)

    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.

  11. Molecular cloning and functional analysis of duck Toll-like receptor 5.

    Science.gov (United States)

    Xiong, Dan; Pan, Zhiming; Kang, Xilong; Wang, Jing; Song, Li; Jiao, Xinan

    2014-08-01

    Toll-like receptor 5 (TLR5) is responsible for the recognition of bacterial flagellin in vertebrates. In this study, we cloned the single-exon TLR5 gene of the Maya breed of Common Shelduck (Tadorna tadorna). The TLR5 open reading frame is 2580 bp in length and encodes an 859-amino acid protein. The putative amino acid sequence of duck TLR5 consisted of a signal peptide sequence, 11 leucine-rich repeat domains, a leucine-rich repeat C-terminal domain, a transmembrane domain, and an intracellular Toll-interleukin-1 receptor domain. The duck TLR5 gene was highly expressed in the lung, bone marrow, spleen, and liver; moderately expressed in kidney, small intestine, large intestine, and brain. A plasmid expressing duck TLR5 was constructed and transfected into HEK293T cells, and expression was confirmed by indirect immunofluorescence assay. HEK293T cells transfected with duck TLR5- and NF-κB-luciferase-containing plasmids significantly responded to flagellin from Salmonella typhimurium, indicating that it is a functional TLR5 homolog.

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

    Directory of Open Access Journals (Sweden)

    Selvarajoo Kumar

    2011-04-01

    Full Text Available Abstract 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.

  13. Pattern Recognition via the Toll-Like Receptor System in the Human Female Genital Tract

    Directory of Open Access Journals (Sweden)

    Kaei Nasu

    2010-01-01

    Full Text Available The mucosal surface of the female genital tract is a complex biosystem, which provides a barrier against the outside world and participates in both innate and acquired immune defense systems. This mucosal compartment has adapted to a dynamic, non-sterile environment challenged by a variety of antigenic/inflammatory stimuli associated with sexual intercourse and endogenous vaginal microbiota. Rapid innate immune defenses against microbial infection usually involve the recognition of invading pathogens by specific pattern-recognition receptors recently attributed to the family of Toll-like receptors (TLRs. TLRs recognize conserved pathogen-associated molecular patterns (PAMPs synthesized by microorganisms including bacteria, fungi, parasites, and viruses as well as endogenous ligands associated with cell damage. Members of the TLR family, which includes 10 human TLRs identified to date, recognize distinct PAMPs produced by various bacterial, fungal, and viral pathogens. The available literature regarding the innate immune system of the female genital tract during human reproductive processes was reviewed in order to identify studies specifically related to the expression and function of TLRs under normal as well as pathological conditions. Increased understanding of these molecules may provide insight into site-specific immunoregulatory mechanisms in the female reproductive tract.

  14. [Toll-like receptors in development and function of the hematopoietic system].

    Science.gov (United States)

    Vadillo, Eduardo; Pelayo, Rosana

    2012-01-01

    Virus, bacteria, fungi and parasites are pathogens to which individuals are constantly exposed. Pathogen recognition by cells of the immune system is carried out by a growing list of pattern-recognition receptors (PRRs) which are evolutionally conserved and absent in mammals, named pathogen-associated molecular patterns (PAMPs). PRRs can be found in extracellular matrix, within cytoplasm and on cellular membranes. Among the membrane PRRs, Toll-like receptors (TLRs) induce the production of pro-inflammatory cytokines and the expression of co-stimulatory molecules upon stimulation on mature cells, resulting in the triggering of immune danger signals. Recent reports showing the regulation of hematopoiesis by TLRs, suggest that they are involved in the most primitive stages of hematopoietic development and contribute to emergent replenishment of innate immune cells. These data entail TLRs to hematopoiesis and also revolutionize our understanding of the mechanisms governing infection responses. In this review, we focus on the most relevant findings from the TLR discovery to the use of TLR agonists and antagonists in novel therapies for infectious, autoimmune and neoplastic diseases. Of special interest is the research progress in the TLR functional expression by primitive hematopoietic stem and progenitor cells.

  15. Toll-like receptor 4 deficiency: Smaller infarcts, but nogain in function

    Directory of Open Access Journals (Sweden)

    Hoeft Andreas

    2007-06-01

    Full Text Available Abstract Backgound It has been reported that Toll-like receptor 4 (TLR4 deficiency reduces infarct size after myocardial ischemia/reperfusion (MI/R. However, measurement of MI/R injury was limited and did not include cardiac function. In a chronic closed-chest model we assessed whether cardiac function is preserved in TLR4-deficient mice (C3H/HeJ following MI/R, and whether myocardial and systemic cytokine expression differed compared to wild type (WT. Results Infarct size (IS in C3H/HeJ assessed by TTC staining after 60 min ischemia and 24h reperfusion was significantly smaller than in WT. Despite a smaller infarct size, echocardiography showed no functional difference between C3H/HeJ and WT. Left-ventricular developed pressure measured with a left-ventricular catheter was lower in C3H/HeJ (63.0 ± 4.2 mmHg vs. 77.9 ± 1.7 mmHg in WT, p Conclusion These results demonstrate that, although a mutant TLR4 signaling cascade reduces myocardial IS and serum cytokine levels, it does not preserve myocardial function. The change in inflammatory response, secondary to a non-functional TLR-4 receptor, may contribute to the observed dichotomy between infarct size and function in the TLR-4 mutant mouse.

  16. Are Toll-like receptor gene polymorphisms associated with prostate cancer?

    Directory of Open Access Journals (Sweden)

    Kutikhin AG

    2012-02-01

    Full Text Available Anton G Kutikhin, Arseniy E YuzhalinDepartment of Epidemiology, Kemerovo State Medical Academy, Kemerovo, Russian FederationAbstract: The suggestion that there is a connection between chronic intraprostatic inflammation and prostate cancer was declared some years ago. As Toll-like receptors (TLRs are the key players in the processes of chronic intraprostatic inflammation, there is a hypothesis that TLR gene polymorphisms may be associated with prostate cancer risk. Although a number of comprehensive studies have been conducted on large samples in various countries, reliable connections between these single nucleotide polymorphisms and prostate cancer risk, stage, grade, aggressiveness, ability to metastasize, and mortality have not been detected. Results have also varied slightly in different populations. The data obtained regarding the absence of connection between the polymorphisms of the genes encoding interleukin-1 receptor-associated kinases (IRAK1 and IRAK4 and prostate cancer risk might indicate a lack of association between inherited variation in the TLR signaling pathway and prostate cancer risk. It is possible to consider that polymorphisms of genes encoding TLRs and proteins of the TLR pathway also do not play a major role in the etiology and pathogenesis of prostate cancer. Feasibly, it would be better to focus research on associations between TLR single nucleotide polymorphisms and cancer risk in other infection-related cancer types.Keywords: TLRs, single nucleotide polymorphisms, genetic variation, inflammation, innate immunity

  17. Molecular cloning and characterization of Toll-like receptors 1-10 in sheep.

    Science.gov (United States)

    Chang, Jung-Su; Russell, George C; Jann, Oliver; Glass, Elizabeth J; Werling, Dirk; Haig, David M

    2009-01-15

    Toll-like receptors (TLRs) are pattern-recognition receptors that trigger innate immune responses and stimulate adaptive immunity. Currently, only partial information is available for sheep TLR genes. The aims of this study were to clone and sequence the coding regions of all 10 ovine TLR genes and compare the sequences with those of other mammalian species. The coding sequences for ovine TLRs 1-10 and the 3'-untranslated sequences for ovine TLR1, 6 and 10 have been obtained. Ovine TLR6 exhibited a distinctive 3'-end sequence that resembled a rare splice variant of bovine TLR6, but appeared to represent the major TLR6 transcript in the sheep. qRT-PCR confirmed the presence of TLR transcripts in blood mononuclear cells, alveolar macrophages, keratinocytes and lymph node tissues. Comparative sequence analysis showed that the sheep TLRs share high sequence similarity with the respective cattle, pig, human and mouse genes and are likely derived from the same ancestral sequence.

  18. Experimental models of acute infection and Toll-like receptor driven septic shock.

    Science.gov (United States)

    Ferstl, Ruth; Spiller, Stephan; Fichte, Sylvia; Dreher, Stefan; Kirschning, Carsten J

    2009-01-01

    Mainly Gram-negative and Gram-positive bacterial infections, but also other infections such as with fungal or viral pathogens, can cause the life-threatening clinical condition of septic shock. Transgression of the host immune response from a local level limited to the pathogen's place of entry to the systemic level is recognised as a major mode of action leading to sepsis. This view has been established upon demonstration of the capacity of specific pathogen-associated molecular patterns (PAMPs) to elicit symptoms of septic shock upon systemic administration. Immune stimulatory PAMPs are agonists of soluble, cytoplasmic, as well as/or cell membrane-anchored and/or -spanning pattern recognition receptors (PRRs) such as Toll-like receptors (TLRs). However, reflection of pathogen-host crosstalk triggering sepsis pathogenesis upon an infection by a host response to challenge with an isolated PAMP is incomplete. Therefore, an experimental model more reflective of pathogen-host interaction requires experimental host confrontation with a specific pathogen in its viable form resulting in a collective stimulation of a variety of specific PRRs. This chapter describes methods to analyse innate pathogen sensing by the host on both a cellular and systemic level.

  19. Toll-like receptor expression in the nervous system of bovine alpha-herpesvirus-infected calves.

    Science.gov (United States)

    Marin, M S; Quintana, S; Leunda, M R; Odeón, A C; Pérez, S E

    2014-10-01

    In this study, the expression levels of viral Toll-like receptors (TLRs) in the nervous system of bovine herpesvirus type 5 (BoHV-5)-infected calves were investigated. A significant increase in the expression of TLRs 3 and 7-9 was found in the anterior cerebral cortex during acute infection and viral reactivation. In the trigeminal ganglia, only TLR9 expression was significantly affected. The magnitude of the increase was lower in BoHV-1-infected calves, suggesting that a restricted immune response might protect against exacerbated inflammatory responses in the brain. This work describes, for the first time, the involvement of TLRs 3 and 7-9 in the recognition of BoHV in the bovine nervous system, indicating that the expression of these receptors might be associated with the development of neurological disease. Modulation of the signalling pathways mediated by TLRs might provide an effective approach to control the neuro-immune response to BoHV-5, which may be responsible for neurological lesions.

  20. Toll-Like Receptor 9 Promotes Cardiac Inflammation and Heart Failure during Polymicrobial Sepsis

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    Ralph Lohner

    2013-01-01

    Full Text Available Background. Aim was to elucidate the role of toll-like receptor 9 (TLR9 in cardiac inflammation and septic heart failure in a murine model of polymicrobial sepsis. Methods. Sepsis was induced via colon ascendens stent peritonitis (CASP in C57BL/6 wild-type (WT and TLR9-deficient (TLR9-D mice. Bacterial load in the peritoneal cavity and cardiac expression of inflammatory mediators were determined at 6, 12, 18, 24, and 36 h. Eighteen hours after CASP cardiac function was monitored in vivo. Sarcomere length of isolated cardiomyocytes was measured at 0.5 to 10 Hz after incubation with heat-inactivated bacteria. Results. CASP led to continuous release of bacteria into the peritoneal cavity, an increase of cytokines, and differential regulation of receptors of innate immunity in the heart. Eighteen hours after CASP WT mice developed septic heart failure characterised by reduction of end-systolic pressure, stroke volume, cardiac output, and parameters of contractility. This coincided with reduced cardiomyocyte sarcomere shortening. TLR9 deficiency resulted in significant reduction of cardiac inflammation and a sustained heart function. This was consistent with reduced mortality in TLR9-D compared to WT mice. Conclusions. In polymicrobial sepsis TLR9 signalling is pivotal to cardiac inflammation and septic heart failure.

  1. Biocomputational analysis of evolutionary relationship between toll-like receptor and nucleotide-binding oligomerization domain-like receptors genes

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    Rabia Bhardwaj

    2016-11-01

    Full Text Available Aim: The active domains (TIR and NACHT of the pattern recognition receptors (PRRs: Toll-like receptors [TLRs] and nucleotide-binding oligomerization domain [NOD]-like receptors [NLR], respectively are the major hotspots of evolution as natural selection has crafted their final structure by substitution of residues over time. This paper addresses the evolutionary perspectives of the TLR and NLR genes with respect to the active domains in terms of their chronological fruition, functional diversification, and species-specific stipulation. Materials and Methods: A total of 48 full-length cds (and corresponding peptide of the domains were selected as representatives of each type of PRRs, belonging to divergent animal species, for the biocomputational analyses. The secondary and tertiary structure of the taurine TIR and NACHT domains was predicted to compare the relatedness among the domains under study. Results: Multiple sequence alignment and phylogenetic tree results indicated that these host-specific PRRs formed entirely different clusters, with active domains of NLRs (NACHT evolved earlier as compared to the active domains of TLRs (TIR. Each type of TLR or NLR shows comparatively less variation among the animal species due to the specificity of action against the type of microbes. Conclusion: It can be concluded from the study that there has been no positive selection acting on the domains associated with disease resistance which is a fitness trait indicating the extent of purifying pressure on the domains. Gene duplication could be a possible reason of genesis of similar kinds of TLRs (virus or bacteria specific.

  2. Biocomputational analysis of evolutionary relationship between toll-like receptor and nucleotide-binding oligomerization domain-like receptors genes

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    Bhardwaj, Rabia; Mukhopadhyay, Chandra Shekhar; Deka, Dipak; Verma, Ramneek; Dubey, P. P.; Arora, J. S.

    2016-01-01

    Aim: The active domains (TIR and NACHT) of the pattern recognition receptors (PRRs: Toll-like receptors [TLRs] and nucleotide-binding oligomerization domain [NOD]-like receptors [NLR], respectively) are the major hotspots of evolution as natural selection has crafted their final structure by substitution of residues over time. This paper addresses the evolutionary perspectives of the TLR and NLR genes with respect to the active domains in terms of their chronological fruition, functional diversification, and species-specific stipulation. Materials and Methods: A total of 48 full-length cds (and corresponding peptide) of the domains were selected as representatives of each type of PRRs, belonging to divergent animal species, for the biocomputational analyses. The secondary and tertiary structure of the taurine TIR and NACHT domains was predicted to compare the relatedness among the domains under study. Results: Multiple sequence alignment and phylogenetic tree results indicated that these host-specific PRRs formed entirely different clusters, with active domains of NLRs (NACHT) evolved earlier as compared to the active domains of TLRs (TIR). Each type of TLR or NLR shows comparatively less variation among the animal species due to the specificity of action against the type of microbes. Conclusion: It can be concluded from the study that there has been no positive selection acting on the domains associated with disease resistance which is a fitness trait indicating the extent of purifying pressure on the domains. Gene duplication could be a possible reason of genesis of similar kinds of TLRs (virus or bacteria specific). PMID:27956772

  3. Expression profiles and function of Toll-like receptors in human corneal epithelia

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    WU Xin-yi; GAO Jian-lu; REN Mei-yu

    2007-01-01

    Background Toll-like receptors play an important role in the human immune system. This study was conducted to investigate the expression profiles and function of Toll-like receptor (TLR)1-9 in human corneal epithelium.Methods The expression of TLR1-9 mRNA in 20 human donor corneal epithelia samples abraded during photorefractive keratotomy (PRK) and cultivated telomerase-immortalized human corneal epithelial cells (THCEs) was examined by semi-quantitative reverse-transcriptase polymerase chain reaction (RT-PCR) analysis. Human peripheral blood mononuclear cells (PBMCs) were used as positive controls. The expression of the TLR2 and TLR4 proteins was detected by Western analysis. ELISA was used to detect IL-8 secretion from THCEs challenged with ligands for TLR3 and TLR4 with and without antibody blockade.Results The expression of TLR1-9 at the mRNA level was detected in the epithelia of 20 patients and in THCE.Significant differences among individuals were observed. One patient was found to lack of the expression of TLR3, 4, 6 and 8, whereas another did not express TLR5. The expression of TLR2 and TLR4 protein was detected in human corneal epithelial cells. As THCE cells express TLR1-9, cells were challenged with lipopolysaccharides (LPS) and poly I:C to determine whether TLR4 and TLR3 were functional. The results showed that secretion of IL-8 by cells stimulated with LPS and Poly I:C was 7 to 10 fold greater than secretion by unchallenged cells. Blocking TLR4 with an anti-TLR4 antibody significantly inhibited the LPS-induced IL-8 production by THCE (P<0.05).Conclusion Human corneal epithelial cells express multiple TLRs and are able to recognize LPS and poly I:C. Different expression profiles among individuals suggest that differences in the susceptibilities and sensitivities to bacterial and viral infection in human populations relate to different patterns of TLR expression.

  4. Neuroexcitatory effects of morphine-3-glucuronide are dependent on Toll-like receptor 4 signaling

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    Due Michael R

    2012-08-01

    Full Text Available Abstract Background Multiple adverse events are associated with the use of morphine for the treatment of chronic non-cancer pain, including opioid-induced hyperalgesia (OIH. Mechanisms of OIH are independent of opioid tolerance and may involve the morphine metabolite morphine-3-glucuronide (M3G. M3G exhibits limited affinity for opioid receptors and no analgesic effect. Previous reports suggest that M3G can act via the Toll-like receptor 4 (TLR4/myeloid differentiation protein-2 (MD-2 heterodimer in the central nervous system to elicit pain. Methods Immunoblot and immunocytochemistry methods were used to characterize the protein expression of TLR4 present in lumbar dorsal root ganglion (DRG. Using in vitro intracellular calcium and current clamp techniques, we determined whether TLR4 activation as elicited by the prototypical agonists of TLR4, lipopolysaccharide (LPS and M3G, contributed to changes in intracellular calcium and increased excitation. Rodents were also injected with M3G to determine the degree to which M3G-induced tactile hyperalgesia could be diminished using either a small molecule inhibitor of the MD-2/TLR4 complex in rats or TLR4 knockout mice. Whole cell voltage-clamp recordings were made from small- and medium-diameter DRG neurons (25 μm  Results We observed that TLR4 immunoreactivity was present in peptidergic and non-peptidergic sensory neurons in the DRG. Non-neuronal cells in the DRG lacked evidence of TLR4 expression. Approximately 15% of assayed small- and medium-diameter sensory neurons exhibited a change in intracellular calcium following LPS administration. Both nociceptive and non-nociceptive neurons were observed to respond, and approximately 40% of these cells were capsaicin-insensitive. Increased excitability observed in sensory neurons following LPS or M3G could be eliminated using Compound 15, a small molecule inhibitor of the TLR4/MD-2 complex. Likewise, systemic injection of M3G induced rapid tactile, but

  5. PHLDA1 Promotes Lung Contusion by Regulating the Toll-Like Receptor 2 Signaling Pathway

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    Shaohua Wang

    2016-12-01

    Full Text Available Background/Aims: Lung contusion is a potentially lethal injury. Pleckstrin homology-like domain family A, member-1 (PHLDA1 is known to play crucial roles in cell proliferation and apoptosis. In this study, we investigated the biological role of PHLDA1 in lung contusion. Methods: The expression levels of PHLDA1 and TLR2 were detected by real time PCR and western. The cytokines were determined by ELISA. The inflammatory factors were detected by flow cytometry. The lung injury was determined by HE staining. Results: PHLDA1 gene and protein expression levels were up-regulated in a mouse lung-contusion model, together with increased neutrophil and macrophage contents. Down-regulation of PHLDA1 by interfering RNA (siPHLDA1 mice decreased lung injury and neutrophil infiltration. Inflammatory factors, including interleukin (IL-1β, IL-6, mouse homolog of human growth-regulated oncogene-α (KC, tumor necrosis factor-α, CC chemokine ligand (CCL 2, and CCL12 were also decreased in siPHLDA1 mice. Expression levels of Toll-like receptor 2 (TLR2 were increased in the lung-contusion mouse model, but were decreased when PHLDA1 was down-regulated. Conclusion: These results demonstrate that PHLDA1 plays a critical role in the development of progressive lung contusion and subsequent inflammation. This information furthers our understanding of the pathogenesis of lung contusion, and suggests that PHLDA1 blockade may represent a potential therapeutic strategy for the treatment of this injury.

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

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    Bustamante J

    2012-10-01

    Full Text Available J Bustamante,1 E Tamayo,2 J Herreros3,41Department of Cardiovascular Surgery, Hospital Universitario La Princesa, Madrid, 2Department of Anesthesiology and Intensive Care, Hospital Clinico Universitario de Valladolid, Valladolid, 3Department of Cardiovascular Surgery, Hospital Universitario Valdecilla, Santander, 4Biomedical Engineering Institute of Santander, Santander, SpainAbstract: 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.Keywords: genome-wide association study, single-nucleotide polymorphism, innate immune system, ischemic/reperfusion, myocardial infarction

  7. Characterization of promoter sequence of toll-like receptor genes in Vechur cattle

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    R. Lakshmi

    2016-06-01

    Full Text Available 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.

  8. Novel Toll-like receptor-4 deficiency attenuates trastuzumab (Herceptin induced cardiac injury in mice

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    Yousif Nasser

    2011-10-01

    Full Text Available Abstract Background Cardiac inflammation and generation of oxidative stress are known to contribute to trastuzumab (herceptin induced cardiac toxicity. Toll-like receptors (TLRs are a part of the innate immune system and are involved in cardiac stress reactions. Since TLR4 might play a relevant role in cardiac inflammatory signaling, we investigated whether or not TLR4 is involved in trastuzumab induced cardiotoxicity. Methods Seven days after a single injection of herceptin (2 mg/kg; i.p., left ventricular pressure volume loops were measured in HeN compotent (TLR4+/+ and HeJ mutant (TLR4-/- treated with trastuzumab and control mice. Immunofluorescent staining for monocyte infiltration and analyses of plasma by (ELISAs for different chemokines including: MCP-1and tumor necrosis factor-α (TNF-α, Western immunoblotting assay for ICAM-1, and used troponin I for cardiac injury marker. Results Trastuzumab injection resulted in an impairment of left ventricular function in TLR-4 competent (HeN, in contrast TLR4-/- trastuzumab mice showed improved left ventricular function EF%, CO; p -/-; p -/-, marked reduction of myocardial troponin-I levels in TLR4-deficient mice. Data are presented as means ± SE; n = 8 in each group p Conclusions Treatment with trastuzumab induces an inflammatory response that contributes to myocardial tissue TLR4 mediates chemokine expression (TNF-α, MCP-1and ICAM-1, so in experimental animals TLR4 deficiency improves left ventricular function and attenuates pathophysiological key mechanisms in trastuzumab induced cardiomyopathy.

  9. Intra-uterine Growth Restriction Downregulates the Hepatic Toll Like Receptor-4 Expression and Function

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    Ozlem Equils

    2005-01-01

    Full Text Available Maternal starvation is a significant cause of intrauterine growth restriction (IUGR in the world and increases the risk of infection in the neonate. We examined the effect of maternal starvation on Toll like receptor (TLR4 expression in hepatic, splenic and intestinal tissues obtained from the adult IUGR offspring of prenatal calorie restricted rats. The hepatic TLR4 protein concentration was undetectable in the IUGR rats that had restricted milk intake during the suckling period (SM/SP; n = 4, p < 0.05 as compared to the normal growth controls (CM/CP; n=4, and access to ad lib milk intake during the sucking period partially corrected the hepatic TLR4 expression (SM/CP; n = 4. IUGR had no effect on the splenic (n = 4 or intestinal (n = 4 TLR4 mRNA levels. In the liver, IUGR led to a 20% increase in baseline tumor necrosis factor (TNF-α mRNA expression ( p < 0.03 and a 70% increase in interleukin-1β (IL-1β mRNA expression ( p < 0.008 as compared to the control rats (CM/CP; n = 7. LPS-induced hepatic TNF-α release was significantly higher in SM/SP as compared to CM/CP. We propose that IUGR dysregulates TLR4 expression and function in the offspring, which may help explain the increased risk of Gram-negative sepsis and inflammatory diseases in this population.

  10. Expression of Toll-like receptor 4 in hippocampus of rat model with temporal lobe epilepsy

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    PAN Li-ping

    2013-12-01

    Full Text Available Objective To investigate the expression of Toll-like receptor 4 (TLR4 protein in hippocampus of rat model with temporal lobe epilepsy after status epilepticus (SE and explore its function in the pathogenesis of temporal lobe epilepsy. Methods Rat model with temporal lobe epilepsy was induced by lithium chloride (LiCl-pilocarpine. Total protein was extracted from hippocampus and rat brain slices were obtained at different time points (0, 1, 6, 12, 24, 48 h and 7, 10, 30, 50 d after SE. Western blotting and immunohistochemical staining were used for detection of the expression of TLR4 in the hippocampus. Results The results of Western blotting showed the TLR4 protein expression at 0, 1, 6, 12, 24, 48 h and 7, 10, 30 d after SE was higher than that in the control group (P 0.05. Conclusion TLR4 protein was mainly expressed in cytoplasm of pyramidal cells in CA3 area of hippocampus. TLR4 protein expression in the hippocampus was increased in varying degrees at different observation time points after SE, indicating that TLR4 may play an important role in the development of epilepsy.

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

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    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.

  12. Placental Trophoblast Responses to Porphyromonas gingivalis Mediated by Toll-like Receptor-2 and -4

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    Banun Kusumawardani

    2013-09-01

    Full Text Available Trophoblast participates in preventing allorecognition and controlling pathogens that compromise fetal wellbeing. Toll-like receptors recognize conserved sequences on the pathogens surface and trigger effector cell functions. Porphyromonas gingivalis is thought to spread to the umbilical cord and cause fetal growth restriction. Objective: To characterize expression and function of TLR-2 and TLR-4 in trophoblast cells from Porphyromonas gingivalisinfected pregnant rats. Methods: Live Porphyromonas gingivalis were challenged into the maxillary first molar subgingival sulcus of female rats before and/or during pregnancy and sacrified on gestational day (GD 14 and 20. Porphyromonas gingivalis was detected by API-ZYM system in the maternal blood of the retro-orbital venous plexus and the umbilical cord. TLR-2 and TLR-4 expressions in trophoblast cells was detected by immunohistochemistry. Results: Porphyromonas gingivalis was first detected in the maternal blood and finally spread to the umbilical cord. Syncytiotrophoblast, spongitrophoblast and trophoblastic giant cell in treated groups had significantly higher expression of TLR-2 and TLR-4 than control group (p<0.05. Conclusion: Syncytiotrophoblast, spongitrophoblast and trophoblastic giant cell are able to recognize Porphyromonas gingivalis through TLR-2 and TLR-4 expression. The ligation of TLR-2 and TLR-4 promoted cytokine production and induced trophoblast cell death. These findings strengthen links between periodontal disease and fetal growth restriction.DOI: 10.14693/jdi.v20i2.150

  13. The Potential Interplay of Adipokines with Toll-Like Receptors in the Development of Hepatocellular Carcinoma

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    Shen-Nien Wang

    2011-01-01

    Full Text Available Toll-like receptors (TLRs are not only crucial to the initiation of the immune system, but also play a key role in several human inflammatory diseases. Hepatocellular carcinoma (HCC is among those human cancers, which arise from sites of chronic inflammation. Therefore, a number of studies have explored the potential contribution of TLRs to HCC occurrence, which is initiated by exposure to chronic hepatic inflammation of different etiologies (including ethanol, and chronic B and C viral infections. Recent epidemiological data have shown the association of obesity and HCC development. Given the fact that adipose tissues can produce a variety of inflammation-related adipokines, obesity has been characterized as a state of chronic inflammation. Adipokines are therefore considered as important mediators linking inflammation to several metabolic diseases, including cancers. More recently, many experts have also shown the bridging role of TLRs between inflammation and metabolism. Hopefully, to retrieve the potential interaction between TLRs and adipokines in carcinogenesis of HCC will shed a new light on the therapeutic alternative for HCC. In this paper, the authors first review the respective roles of TLRs and adipokines, discuss their mutual interaction in chronic inflammation, and finally anticipate further investigations of this interaction in HCC development.

  14. Toll-like receptor 7 controls the anti-retroviral germinal center response.

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    Edward P Browne

    2011-10-01

    Full Text Available The development of vaccines that can enhance immunity to viral pathogens is an important goal. However, the innate molecular pathways that regulate the strength and quality of the immune response remain largely uncharacterized. To define the role of Toll-like receptor (TLR signaling in control of a model retroviral pathogen, Friend virus (FV, I generated mice in which the TLR signaling adapter Myd88 was selectively deleted in dendritic cell (DC or in B cell lineages. Deletion of Myd88 in DCs had little effect on immune control of FV, while B cell specific deletion of Myd88 caused a dramatic increase in viral infectious centers and a significantly reduced antibody response, indicating that B cell-intrinsic TLR signaling plays a crucial role, while TLR signaling in DCs is less important. I then identified the single-stranded RNA sensing protein TLR7 as being required for antibody-mediated control of FV by analyzing mice deficient in TLR7. Remarkably, B cells in infected TLR7-deficient mice upregulated CD69 and CD86 early in infection, but failed to develop into germinal center B cells. CD4 T cell responses were also attenuated in the absence of TLR7, but CD8 responses were TLR7 independent, suggesting the existence of additional pathways for detection of retroviral particles. Together these results demonstrate that the vertebrate immune system detects retroviruses in vivo via TLR7 and that this pathway regulates a key checkpoint controlling development of germinal center B cells.

  15. Polymorphisms of toll-like receptor 2 and 4 genes in Chagas disease

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    German Zafra

    2008-02-01

    Full Text Available The aim of this study was to test the possible implication of toll-like receptor 2 (TLR2 and TLR4 gene polymorphisms in determining the susceptibility to Chagas' disease. Genotypes were determined by polymerase chain reaction-restriction fragment length polymorphism in 475 individuals from Colombia, 143 seropositive with chagasic cardiomyopathy, 132 seropositive asymptomatic and 200 seronegative. The TLR2 arginine to glutamine substitution at residue 753(Arg753Gln polymorphism was absent in the groups analyzed. The TLR4 Asp299Gly and Thr399Ile polymorphisms are in linkage disequilibrium and we observed a very low frequency of these polymorphisms in our study population (2.6% and 1.8% respectively. The overall TLR2 and TLR4 alleles and genotype distribution in seronegative and seropositive were not significantly different. We compared the frequencies between asymptomatic patients and those with chagasic cardiomyopathy and we did not observe any significant differences in the distribution of alleles or genotypes. In summary, this study corroborates the low frequency of TLR2 and TLR4 polymorphisms observed in other populations and suggest that these do not play an important role in Chagas' disease. The validation of these findings in independent cohorts is needed to firmly establish a role for TLR2 and TLR4 variants in Chagas' disease.

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

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    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.

  17. Drift, not selection, shapes toll-like receptor variation among oceanic island populations.

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    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.

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

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    Khariv, Veronika; Pang, Kevin; Servatius, Richard J; David, Brian T; Goodus, Matthew T; Beck, Kevin D; Heary, Robert F; Elkabes, Stella

    2013-08-01

    Toll-like receptors (TLRs) mediate the induction of the innate immune system in response to pathogens, injury and disease. However, they also play non-immune roles and are expressed in the central nervous system (CNS) during prenatal and postnatal stages including adulthood. Little is known about their roles in the CNS in the absence of pathology. Several members of the TLR family have been implicated in the development of neural and cognitive function although the contribution of TLR9 to these processes has not been well defined. The current studies were undertaken to determine whether developmental TLR9 deficiency affects motor, sensory or cognitive functions. We report that TLR9 deficient (TLR9(-/-)) mice show a hyper-responsive sensory and motor phenotype compared to wild type (TLR9(+/+)) controls. This is indicated by hypersensitivity to thermal stimuli in the hot plate paw withdrawal test, enhanced motor-responsivity under anxious conditions in the open field test and greater sensorimotor reactivity in the acoustic startle response. Prepulse inhibition (PPI) of the acoustic startle response was also enhanced, which indicates abnormal sensorimotor gating. In addition, subtle, but significant, gait abnormalities were noted in the TLR9(-/-) mice on the horizontal balance beam test with higher foot slip numbers than TLR9(+/+) controls. In contrast, spatial learning and memory, assessed by the Morris water maze, was similar in the TLR9(-/-) and TLR9(+/+) mice. These findings support the notion that TLR9 is important for the appropriate development of sensory and motor behaviors.

  19. Expression of Toll-like receptors in nasal epithelium in allergic rhinitis.

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    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.

  20. Diversity in the Toll-Like Receptor Genes of the African Penguin (Spheniscus demersus).

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    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.

  1. Toll-like receptors elicit different recruitment kinetics of monocytes and neutrophils in mouse acute inflammation.

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    Imhof, Beat A; Jemelin, Stephane; Emre, Yalin

    2017-03-16

    Leukocyte recruitment is an important process in combatting pathogens. The largest class of circulating leukocytes are neutrophils, which rapidly invade inflamed tissue, followed by inflammatory Ly6C(+) monocytes. Ly6C(low) monocytes patrol the endothelial wall routinely in the steady state. We recently reported early luminal recruitment of Ly6C(low) monocytes, which preceded and orchestrated neutrophil arrival and extravasation in response to TLR7/8-mediated vascular inflammation. Here we dissected the kinetics of recruitment of monocytes and neutrophils and examined the dynamics of Ly6C(low) monocytes in response to several other Toll-like receptor (TLR) agonists, using intravital confocal microscopy. We observed two types of kinetics in mesenteric veins. TLR2, TLR5 and TLR9 agonists caused early monocyte and neutrophil influx whereas TLR3 and TLR4 agonists rapidly recruited neutrophils and caused Ly6C(low) monocytes to arrive at low levels later on. All TLR agonists, except TLR9, led Ly6C(low) monocytes to meticulously patrol the vascular wall. Finally, these monocytes released pro-inflammatory cytokines and chemokines implicated in neutrophil recruitment in response to TLR2, TLR4 and TLR9 stimulation but not to TLR3 and TLR5 agonists. These results refine our understanding of the early events in the leukocyte recruitment cascade, including the patrolling behaviour of Ly6C(low) monocytes, in TLR-mediated acute vascular inflammation. This article is protected by copyright. All rights reserved.

  2. Network Analysis of Neurodegenerative Disease Highlights a Role of Toll-Like Receptor Signaling

    Directory of Open Access Journals (Sweden)

    Thanh-Phuong Nguyen

    2014-01-01

    Full Text Available 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.

  3. Conservation of toll-like receptor signaling pathways in teleost fish

    Science.gov (United States)

    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.

  4. Regulation of Toll-like receptor 5 gene expression and function on mucosal dendritic cells.

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    Ting Feng

    Full Text Available Toll-like receptor (TLR 5 has been shown to maintain intestinal homeostasis and regulate host defense against enterobacterial infection. However, how TLR5 expression is regulated and its function in the intestine have not been fully elucidated. Here we demonstrate that mucosal dendritic cells (DCs, but not splenic DCs, express high levels of TLR5 protein. Alternatively spliced Tlr5 transcripts were identified but it did not explain the selective expression of TLR5 on mucosal DCs. Treatment with various bacterial ligands downregulated BMDC TLR5 expression, while retinoic acid and host stromal cell-derived signals promoted TLR5 expression in a TGF-β-independent mechanism. Signaling through TLR5 restrained regulatory T (Treg cell generation, and accordingly, TLR5(-/- mice displayed increased frequencies of Foxp3(+ Treg cells in the intestinal lamina propria. Our data indicate that bacterial and host factors differentially regulate DC TLR5 expression. TLR5 signaling regulates immune responses towards the microbiota via modulation of the Treg/effector T cell balance.

  5. Toll-like receptor signalling in regenerative myogenesis: friend and foe.

    Science.gov (United States)

    Hindi, Sajedah M; Kumar, Ashok

    2016-06-01

    Skeletal muscle regeneration in normal and diseased muscle is regulated by multiple factors and cells present in the injured muscle micro-environment. In addition to muscle progenitor cells, several immunocytes participate in the regenerative response. Among them, macrophages are one of the most important components of the immune response that governs the step-wise progression of muscle regeneration. The initial role of macrophages is to phagocytose muscle cell debris and later, through their transition to an anti-inflammatory phenotype, they promote regeneration. However, in several genetic muscle disorders, continuous muscle injury disrupts the balance between pro-inflammatory and anti-inflammatory macrophages, leading to an overall inflammatory milieu and inhibition of muscle regeneration. Accumulating evidence suggests that Toll-like receptor (TLR)-mediated signalling plays an important role in the regulation of macrophage phenotypes during regenerative myogenesis in response to both acute and chronic muscle injury. Here, we discuss the role of TLR signalling in regulating macrophage phenotypes and skeletal muscle regeneration in healthy and diseased muscle. Copyright © 2016 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

  6. The Role of Inflammation in Regulating Platelet Production and Function: Toll-like Receptors in Platelets and Megakaryocytes

    OpenAIRE

    Beaulieu, Lea M.; Freedman, Jane E.

    2009-01-01

    Platelets have been extensively studied as hemostatic regulators, stopping uncontrolled flow of blood from an injured vessel and allowing for repair. However, multiple studies have shown that platelets can interact with bacterial proteins, particularly seen during sepsis and inflammation. Immune cells recognize pathogens through Toll-like Receptors (TLRs). These same receptors allow platelets to recognize bacterial proteins and regulate platelet immunity and function. This review examines the...

  7. Understanding the dynamics of Toll-like Receptor 5 response to flagellin and its regulation by estradiol

    Science.gov (United States)

    Caballero, Ignacio; Boyd, James; Almiñana, Carmen; Sánchez-López, Javier A.; Basatvat, Shaghayegh; Montazeri, Mehrnaz; Maslehat Lay, Nasim; Elliott, Sarah; Spiller, David G.; White, Michael R. H.; Fazeli, Alireza

    2017-01-01

    Toll-like receptors (TLRs) are major players of the innate immune system. Once activated, they trigger a signalling cascade that leads to NF-κB translocation from the cytoplasm to the nucleus. Single cell analysis shows that NF-κB signalling dynamics are a critical determinant of transcriptional regulation. Moreover, the outcome of innate immune response is also affected by the cross-talk between TLRs and estrogen signalling. Here, we characterized the dynamics of TLR5 signalling, responsible for the recognition of flagellated bacteria, and those changes induced by estradiol in its signalling at the single cell level. TLR5 activation in MCF7 cells induced a single and sustained NF-κB translocation into the nucleus that resulted in high NF-κB transcription activity. The overall magnitude of NF-κB transcription activity was not influenced by the duration of the stimulus. No significant changes are observed in the dynamics of NF-κB translocation to the nucleus when MCF7 cells are incubated with estradiol. However, estradiol significantly decreased NF-κB transcriptional activity while increasing TLR5-mediated AP-1 transcription. The effect of estradiol on transcriptional activity was dependent on the estrogen receptor activated. This fine tuning seems to occur mainly in the nucleus at the transcription level rather than affecting the translocation of the NF-κB transcription factor.

  8. Tenascin C upregulates interleukin-6 expression in human cardiac myofibroblasts via toll-like receptor 4

    Institute of Scientific and Technical Information of China (English)

    Azhar Maqbool; Emma J Spary; Iain W Manfield; Michaela Ruhmann; Lorena Zuliani-Alvarez; Filomena O Gamboa-Esteves; Karen E Porter; Mark J Drinkhill; Kim S Midwood; Neil A Turner

    2016-01-01

    AIM:To investigate the effect of Tenascin C(TNC)on the expression of pro-inflammatory cytokines and matrixmetalloproteinases 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(0.1μmol/L,24 h)or a recombinant protein corresponding to different domains of the TNC protein;fibrinogen-like globe(FBG)and fibronectin typeⅢ-like repeats(TNⅢ5-7)(both 1μmol/L,24 h).The expression of the proinflammatory cytokines;interleukin(IL)-6,IL-1β,TNFαand 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)mR NA levels in cultured human CMF but had no significant effect on the other markers studied.The increase in IL-6 mR NA expression was mirrored by an increase in protein secretion as assessed by enzymelinked immunosorbant assay(P<0.01).Treating CMF with the recombinant protein FBG increased IL-6mR NA and protein(P<0.01)whereas the recombinant protein TNⅢ5-7 had no effect.Neither FBG nor TNⅢ5-7 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 TLR4neutralising antisera attenuated the effect of both TNC and FBG on IL-6 mR NA 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.

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

    Directory of Open Access Journals (Sweden)

    Sakthivel Dhanasekaran

    Full Text Available 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

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

    Science.gov (United States)

    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

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

    Science.gov (United States)

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

    2003-01-01

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

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

    Science.gov (United States)

    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.

  13. Toll-like receptor 2 regulates organic dust-induced airway inflammation.

    Science.gov (United States)

    Poole, Jill A; Wyatt, Todd A; Kielian, Tammy; Oldenburg, Peter; Gleason, Angela M; Bauer, Ashley; Golden, Gregory; West, William W; Sisson, Joseph H; Romberger, Debra J

    2011-10-01

    Organic dust exposure in agricultural environments results in significant airway inflammatory diseases. Gram-positive cell wall components are present in high concentrations in animal farming dusts, but their role in mediating dust-induced airway inflammation is not clear. This study investigated the role of Toll-like receptor (TLR) 2, a pattern recognition receptor for gram-positive cell wall products, in regulating swine facility organic dust extract (DE)-induced airway inflammation in mice. Isolated lung macrophages from TLR2 knockout mice demonstrated reduced TNF-α, IL-6, keratinocyte chemoattractant/CXCL1, but not macrophage inflammatory protein-2/CXCL2 expression, after DE stimulation ex vivo. Next, using an established mouse model of intranasal inhalation challenge, we analyzed bronchoalveolar lavage fluid and lung tissue in TLR2-deficient and wild-type (WT) mice after single and repetitive DE challenge. Neutrophil influx and select cytokines/chemokines were significantly lower in TLR2-deficient mice at 5 and 24 hours after single DE challenge. After daily exposure to DE for 2 weeks, there were significant reductions in total cellularity, neutrophil influx, and TNF-α, IL-6, CXCL1, but not CXCL2 expression, in TLR2-deficient mice as compared with WT animals. Lung pathology revealed that bronchiolar inflammation, but not alveolar inflammation, was reduced in TLR2-deficient mice after repetitive exposure. Airway hyperresponsiveness to methacholine after dust exposure was similar in both groups. Finally, airway inflammatory responses in WT mice after challenge with a TLR2 agonist, peptidoglycan, resembled DE-induced responses. Collectively, these results demonstrate that the TLR2 pathway is important in regulating swine facility organic dust-induced airway inflammation, which suggests the importance of TLR2 agonists in mediating large animal farming-induced airway inflammatory responses.

  14. Microglia are required for astroglial toll-like receptor 4 response and for optimal TLR2 and TLR3 response

    DEFF Research Database (Denmark)

    Holm, Thomas Hellesøe; Draeby, Dina; Owens, Trevor

    2012-01-01

    Within the central nervous system, astrocytes and microglia are the primary responders to endogenous ligands released upon injury and stress, as well as to infectious pathogens. Toll-like receptors (TLRs) are implicated in recognition of both types of stimulus. Whether astrocytes respond as stron......Within the central nervous system, astrocytes and microglia are the primary responders to endogenous ligands released upon injury and stress, as well as to infectious pathogens. Toll-like receptors (TLRs) are implicated in recognition of both types of stimulus. Whether astrocytes respond...... as strongly as microglia to TLR agonists remains contentious. In this study, we have rigorously purified astrocytes to determine their capacity for autonomous TLR response, in absence of microglia. We used flow cytometry and differential adhesion as well as a myeloid lineage-specific suicide gene to purify...

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

    Energy Technology Data Exchange (ETDEWEB)

    Sabatino, María Eugenia; Sosa, Liliana del Valle; Petiti, Juan Pablo; Mukdsi, Jorge Humberto [Centro de Microscopía Electrónica, Instituto de Investigaciones en Ciencias de la Salud (INICSA-CONICET), Facultad de Ciencias Médicas, Universidad Nacional de Córdoba, Av. Enrique Barros y Enfermera Gordillo, Ciudad Universitaria, CP 5000, Córdoba (Argentina); Mascanfroni, Iván Darío; Pellizas, Claudia Gabriela [Centro de Investigaciones en Bioquímica Clínica e Inmunología (CIBICI-CONICET), Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Av. Haya de la Torre y Medina Allende, Ciudad Universitaria, CP 5000, Córdoba (Argentina); Gutiérrez, Silvina; Torres, Alicia Inés [Centro de Microscopía Electrónica, Instituto de Investigaciones en Ciencias de la Salud (INICSA-CONICET), Facultad de Ciencias Médicas, Universidad Nacional de Córdoba, Av. Enrique Barros y Enfermera Gordillo, Ciudad Universitaria, CP 5000, Córdoba (Argentina); De Paul, Ana Lucía, E-mail: adepaul@cmefcm.uncor.edu [Centro de Microscopía Electrónica, Instituto de Investigaciones en Ciencias de la Salud (INICSA-CONICET), Facultad de Ciencias Médicas, Universidad Nacional de Córdoba, Av. Enrique Barros y Enfermera Gordillo, Ciudad Universitaria, CP 5000, Córdoba (Argentina)

    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

  16. Regulation of angiogenesis, mural cell recruitment and adventitial macrophage behavior by Toll-like receptors.

    Science.gov (United States)

    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.

  17. Systemic Toll-like receptor stimulation suppresses experimental allergic asthma and autoimmune diabetes in NOD mice.

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    Aude Aumeunier

    Full Text Available BACKGROUND: Infections may be associated with exacerbation of allergic and autoimmune diseases. Paradoxically, epidemiological and experimental data have shown that some microorganisms can also prevent these pathologies. This observation is at the origin of the hygiene hypothesis according to which the decline of infections in western countries is at the origin of the increased incidence of both Th1-mediated autoimmune diseases and Th2-mediated allergic diseases over the last decades. We have tested whether Toll-like receptor (TLR stimulation can recapitulate the protective effect of infectious agents on allergy and autoimmunity. METHODS AND FINDINGS: Here, we performed a systematic study of the disease-modifying effects of a set of natural or synthetic TLR agonists using two experimental models, ovalbumin (OVA-induced asthma and spontaneous autoimmune diabetes, presenting the same genetic background of the non obese diabetic mouse (NOD that is highly susceptible to both pathologies. In the same models, we also investigated the effect of probiotics. Additionally, we examined the effect of the genetic invalidation of MyD88 on the development of allergic asthma and spontaneous diabetes. We demonstrate that multiple TLR agonists prevent from both allergy and autoimmunity when administered parenterally. Probiotics which stimulate TLRs also protect from these two diseases. The physiological relevance of these findings is further suggested by the major acceleration of OVA-induced asthma in MyD88 invalidated mice. Our results strongly indicate that the TLR-mediated effects involve immunoregulatory cytokines such as interleukin (IL-10 and transforming growth factor (TGF-beta and different subsets of regulatory T cells, notably CD4+CD25+FoxP3+ T cells for TLR4 agonists and NKT cells for TLR3 agonists. CONCLUSIONS/SIGNIFICANCE: These observations demonstrate that systemic administration of TLR ligands can suppress both allergic and autoimmune responses

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

    Science.gov (United States)

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

    2016-01-01

    Background Cigarette smoking is a major risk factor for lung cancer, asthma, and oral cancer, and is central to the altered innate immune responsiveness to infection. Many hypotheses have provided evidence that cigarette smoking induces more genetic changes in genes involved in the development of many cigarette-related diseases. This alteration may be from single-nucleotide polymorphisms (SNPs) in innate immunity genes, especially the toll-like receptors (TLRs). Objective In this study, the genotype frequencies of TLR2 and TLR6 in smoking and nonsmoking population were examined. Methods Saliva samples were collected from 177 smokers and 126 nonsmokers. The SNPs used were rs3804100 (1350 T/C, Ser450Ser) and rs3804099 (597 T/C, Asn199Asn) for TLR2 and rs3796508 (979 G/A, Val327Met) and rs5743810 (745 T/C, Ser249Pro) for TLR6. Results Results showed that TLR2 rs3804100 has a significant effect in short-term smokers (OR =2.63; P=0.04), and this effect is not observed in long-term smokers (>5 years of smoking). Therefore, this early mutation may be repaired by the DNA repair system. For TLR2 rs3804099, the variation in genotype frequencies between the smokers and control patients was due to a late mutation, and its protective role appears only in long-term smokers (OR =0.40, P=0.018). In TLR6 rs5743810, the TT genotype is significantly higher in smokers than in nonsmokers (OR =6.90). The effect of this SNP is observed in long-term smokers, regardless of the smoking regime per day. Conclusion TLR2 (rs3804100 and rs3804099) and TLR6 (rs5743810) can be used as a potential index in the diagnosis and prevention of more diseases caused by smoking. PMID:27920557

  19. Toll-like receptor 2 gene polymorphisms, pulmonary tuberculosis, and natural killer cell counts

    Directory of Open Access Journals (Sweden)

    Tsen Chia-Cheng

    2010-01-01

    Full Text Available Abstract Background To investigate whether the toll-like receptor 2 polymorphisms could influence susceptibility to pulmonary TB, its phenotypes, and blood lymphocyte subsets. Methods A total of 368 subjects, including 184 patients with pulmonary TB and 184 healthy controls, were examined for TLR2 polymorphisms over locus -100 (microsatellite guanine-thymine repeats, -16934 (T>A, -15607 (A>G, -196 to -174 (insertion>deletion, and 1350 (T>C. Eighty-six TB patients were examined to determine the peripheral blood lymphocyte subpopulations. Results We newly identified an association between the haplotype [A-G-(insertion-T] and susceptibility to pulmonary TB (p = 0.006, false discovery rate q = 0.072. TB patients with systemic symptoms had a lower -196 to -174 deletion/deletion genotype frequency than those without systemic symptoms (5.7% vs. 17.7%; p = 0.01. TB patients with the deletion/deletion genotype had higher blood NK cell counts than those carrying the insertion allele (526 vs. 243.5 cells/μl, p = 0.009. TB patients with pleuritis had a higher 1350 CC genotype frequency than those without pleuritis (12.5% vs. 2.1%; p = 0.004. TB patients with the 1350 CC genotype had higher blood NK cell counts than those carrying the T allele (641 vs. 250 cells/μl, p = 0.004. TB patients carrying homozygous short alleles for GT repeats had higher blood NK cell counts than those carrying one or no short allele (641 vs. 250 cells/μl, p = 0.004. Conclusions TLR2 genetic polymorphisms influence susceptibility to pulmonary TB. TLR2 variants play a role in the development of TB phenotypes, probably by controlling the expansion of NK cells.

  20. Age-dependent maturation of Toll-like receptor-mediated cytokine responses in Gambian infants.

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    Sarah Burl

    Full Text Available The global burden of neonatal and infant mortality due to infection is staggering, particularly in resource-poor settings. Early childhood vaccination is one of the major interventions that can reduce this burden, but there are specific limitations to inducing effective immunity in early life, including impaired neonatal leukocyte production of Th1-polarizing cytokines to many stimuli. Characterizing the ontogeny of Toll-like receptor (TLR-mediated innate immune responses in infants may shed light on susceptibility to infection in this vulnerable age group, and provide insights into TLR agonists as candidate adjuvants for improved neonatal vaccines. As little is known about the leukocyte responses of infants in resource-poor settings, we characterized production of Th1-, Th2-, and anti-inflammatory-cytokines in response to agonists of TLRs 1-9 in whole blood from 120 Gambian infants ranging from newborns (cord blood to 12 months of age. Most of the TLR agonists induced TNFα, IL-1β, IL-6, and IL-10 in cord blood. The greatest TNFα responses were observed for TLR4, -5, and -8 agonists, the highest being the thiazoloquinoline CLO75 (TLR7/8 that also uniquely induced cord blood IFNγ production. For most agonists, TLR-mediated TNFα and IFNγ responses increased from birth to 1 month of age. TLR8 agonists also induced the greatest production of the Th1-polarizing cytokines TNFα and IFNγ throughout the first year of life, although the relative responses to the single TLR8 agonist and the combined TLR7/8 agonist changed with age. In contrast, IL-1β, IL-6, and IL-10 responses to most agonists were robust at birth and remained stable through 12 months of age. These observations provide fresh insights into the ontogeny of innate immunity in African children, and may inform development of age-specific adjuvanted vaccine formulations important for global health.

  1. Toll-like receptor polymorphisms and susceptibility to urinary tract infections in adult women.

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    Thomas R Hawn

    Full Text Available 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.

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

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    Wu Chunhua

    2009-05-01

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

  3. Induction of IgG3 to LPS via Toll-like receptor 4 co-stimulation.

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    Francisco J Quintana

    Full Text Available B-cells integrate antigen-specific signals transduced via the B-cell receptor (BCR and antigen non-specific co-stimulatory signals provided by cytokines and CD40 ligation in order to produce IgG antibodies. Toll-like receptors (TLRs also provide co-stimulation, but the requirement for TLRs to generate T-cell independent and T-cell dependent antigen specific antibody responses is debated. Little is known about the role of B-cell expressed TLRs in inducing antigen-specific antibodies to antigens that also activate TLR signaling. We found that mice lacking functional TLR4 or its adaptor molecule MyD88 harbored significantly less IgG3 natural antibodies to LPS, and required higher amounts of LPS to induce anti-LPS IgG3. In vitro, BCR and TLR4 signaling synergized, lowering the threshold for production of T-cell independent IgG3 and IL-10. Moreover, BCR and TLR4 directly associate through the transmembrane domain of TLR4. Thus, in vivo, BCR/TLR synergism could facilitate the induction of IgG3 antibodies against microbial antigens that engage both innate and adaptive B-cell receptors. Vaccines might exploit BCR/TLR synergism to rapidly induce antigen-specific antibodies before significant T-cell responses arise.

  4. Involvement of Toll-Like Receptor 2 and Pro-Apoptotic Signaling Pathways in Bone Remodeling in Osteomyelitis

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    Qianbo Chen

    2014-11-01

    Full Text Available Background and Aims: Osteomyelitis is a common manifestation of invasive Staphylococcus aureus infection characterized by bone loss and destruction. We investigated the role of toll-like receptor 2 (TLR2 in bacterial recognition and clearance in response to infection with an osteomyelitis isolate of S. aureus. Methods: Apoptosis was assessed in the osteoblastic cell line MC3T3-E1 by Annexin V-FITC/PI staining and flow cytometry. The expression of TLR2 and apoptosis-related and mitogen-activated protein kinase pathway proteins was assessed by qRT-PCR and western blotting. Alkaline phosphatase (ALP activity and calcium deposition were assessed by ALP activity assay and Alizarin red staining. Results: S. aureus induced apoptosis, upregulated TLR2 expression, and activated mitogen-activated protein kinase pathways in a time dependent manner. Inhibition of the c-Jun N-terminal kinase (JNK pathway downregulated TLR2 and suppressed the S. aureus induced activation of pro-apoptotic pathways. Short-hairpin RNA mediated silencing of TLR2 reversed S. aureus induced apoptosis and decrease in ALP activity and calcium deposition, and inhibition of JNK had a similar effect. Conclusion: We showed that osteoblast apoptosis and osteogenic differentiation in response to bacterial invasion are dependent on TLR2 expression and JNK activation, suggesting novel potential therapeutic targets for the treatment of osteomyelitis.

  5. Innate Immunity in Systemic Sclerosis – Role of Toll-Like Receptors, Interferon, and the Potential Impact of Vitamin D

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    Ruxandra Ionescu

    2014-07-01

    Full Text Available Systemic sclerosis (SSc is an autoimmune disease in which vascular damage and immune activation leads to excessive accumulation of extracellular matrix in the skin and internal organs. Although the focus has been on adaptive immunity in SSc, recent data suggest that innate immunity is critically important. The innate immune system, the first-line barrier against pathogens, modulates mechanisms which activate adaptive immunity. Dysregulation of the innate immune system and toll-like receptors (TLRs may link immune abnormalities and fibrosis in SSc. TLR signalling pathways might induce production of Type I interferon (IFN and other cytokines, and represent one of the mechanisms that initiate and develop autoimmunity and subsequent fibrosis. Vitamin D displays many immunomodulatory effects on both innate and adaptive immune responses. Active vitamin D will produce signals via vitamin D receptor and influences TLR stimulation, IFN response, and antimicrobial peptide production. Vitamin D deficiency has been associated with many autoimmune disorders, and can influence clinical phenotype and immune disorders in SSc patients.

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

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    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.

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

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    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.

  8. The protective effect of the anti-Toll-like receptor 9 antibody against acute cytokine storm caused by immunostimulatory DNA

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    Murakami, Yusuke; Fukui, Ryutaro; Motoi, Yuji; Shibata, Takuma; Saitoh, Shin-Ichiroh; Sato, Ryota; Miyake, Kensuke

    2017-01-01

    Toll-like Receptor 9 (TLR9) is an innate immune receptor recognizing microbial DNA. TLR9 is also activated by self-derived DNA, such as mitochondrial DNA, in a variety of inflammatory diseases. We show here that TLR9 activation in vivo is controlled by an anti-TLR9 monoclonal Ab (mAb). A newly established mAb, named NaR9, clearly detects endogenous TLR9 expressed in primary immune cells. The mAb inhibited TLR9-dependent cytokine production in vitro by bone marrow-derived macrophages and conventional dendritic cells. Furthermore, NaR9 treatment rescued mice from fulminant hepatitis caused by administering the TLR9 ligand CpGB and D-(+)-galactosamine. The production of proinflammatory cytokines induced by CpGB and D-(+)-galactosamine was significantly impaired by the mAb. These results suggest that a mAb is a promising tool for therapeutic intervention in TLR9-dependent inflammatory diseases. PMID:28266597

  9. Signatures of positive selection in Toll-like receptor (TLR genes in mammals

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    Areal Helena

    2011-12-01

    Full Text Available Abstract Background Toll-like receptors (TLRs are a major class of pattern recognition receptors (PRRs expressed in the cell surface or membrane compartments of immune and non-immune cells. TLRs are encoded by a multigene family and represent the first line of defense against pathogens by detecting foreigner microbial molecular motifs, the pathogen-associated molecular patterns (PAMPs. TLRs are also important by triggering the adaptive immunity in vertebrates. They are characterized by the presence of leucine-rich repeats (LRRs in the ectodomain, which are associated with the PAMPs recognition. The direct recognition of different pathogens by TLRs might result in different evolutionary adaptations important to understand the dynamics of the host-pathogen interplay. Ten mammal TLR genes, viral (TLR3, 7, 8, 9 and non-viral (TLR1-6, 10, were selected to identify signatures of positive selection that might have been imposed by interacting pathogens and to clarify if viral and non-viral TLRs might display different patterns of molecular evolution. Results By using Maximum Likelihood approaches, evidence of positive selection was found in all the TLRs studied. The number of positively selected codons (PSC ranged between 2-26 codons (0.25%-2.65% with the non-viral TLR4 as the receptor with higher percentage of positively selected codons (2.65%, followed by the viral TLR8 (2.50%. The results indicated that viral and non-viral TLRs are similarly under positive selection. Almost all TLRs have at least one PSC located in the LRR ectodomain which underlies the importance of the pathogen recognition by this region. Conclusions Our results are not in line with previous studies on primates and birds that identified more codons under positive selection in non-viral TLRs. This might be explained by the fact that both primates and birds are homogeneous groups probably being affected by only a restricted number of related viruses with equivalent motifs to be

  10. Extensive polymorphism in the porcine Toll-like receptor 10 gene.

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    Bergman, I-M; Edman, K; Ekdahl, K N; Rosengren, K J; Edfors, I

    2012-02-01

    The great importance of the Toll-like receptors (TLRs) in innate immunity is well established, but one family member--TLR10--remains elusive. TLR10 is expressed in various tissues in several species, but its ligand is not known and its function is still poorly understood. The open reading frame of TLR10 was sequenced in 15 wild boars, representing three populations, and in 15 unrelated domestic pigs of Hampshire, Landrace and Large White origin. Amino acid positions corresponding to detected nonsynonymous single nucleotide polymorphisms (SNPs) were analysed in the crystal structures determined for the human TLR1-TLR2-lipopeptide complex and the human TLR10 Toll/Interleukin 1 receptor (TIR) dimer. SNP occurrence in wild boars and domestic pigs was compared, and haplotypes for the TLR10 gene and the TLR6-1-10 gene cluster were reconstructed. Despite the limited number of animals sequenced in the present study (N = 30), a larger number of SNPs were found in TLR10 than recently reported for TLR1, TLR6 and TLR2. Thirty-three SNPs were detected, of which 20 were nonsynonymous. The relative frequency of nonsynonymous (d(N) ) and synonymous (d(S) ) SNPs between wild boars and domestic pigs was higher in TLR10 than recently reported for TLR1, TLR6 and TLR2. However, the polymorphism reported in the present study seems to leave the function of the TLR10 molecule unaffected. Furthermore, no nonsynonymous SNPs were detected in the part of the gene corresponding to the hinge region of the receptor, probably reflecting rigorously acting functional constraint. The total number of SNPs and the number of nonsynonymous SNPs were significantly lower (P < 0.05) in the wild boars than in the domestic pigs, and fewer TLR10 haplotypes were present in the wild boars. The majority of the TLR6-1-10 haplotypes were specific for either wild boars or domestic pigs, probably reflecting differences in microbial environment and population history.

  11. Two Neisseria meningitidis strains with different ability to stimulate toll-like receptor 4 through the MyD88-independent pathway

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    Mogensen, T.H.; Paludan, Søren Riis; Kilian, Mogens;

    2006-01-01

    , is initiated by pattern recognition receptors, among which Toll-like receptors (TLR)s have been ascribed a particularly important role. We have previously demonstrated that N. meningitidis induce proinflammatory cytokine expression through TLR2 and TLR4. Here we characterize the molecular basis...... for differential activation of the inflammatory response by two N. meningitidis strains. This difference was due to differential ability to activate signal transduction through TLR4, as HEK293 cells expressing TLR4 produced significantly different levels of interleukin-8 in response to these strains. At the level...

  12. A role for Toll-like receptor mediated signals in neutrophils in the pathogenesis of the anti-phospholipid syndrome.

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    Gerd Gladigau

    Full Text Available The anti-phospholipid syndrome (APS is characterized by recurrent thrombosis and occurrence of anti-phospholipid antibodies (aPL. aPL are necessary, but not sufficient for the clinical manifestations of APS. Growing evidence suggests a role of innate immune cells, in particular polymorphonuclear neutrophils (PMN and Toll-like receptors (TLR to be additionally involved. aPL activate endothelial cells and monocytes through a TLR4-dependent signalling pathway. Whether this is also relevant for PMN in a similar way is currently not known. To address this issue, we used purified PMN from healthy donors and stimulated them in the presence or absence of human monoclonal aPL and the TLR4 agonist LPS monitoring neutrophil effector functions, namely the oxidative burst, phagocytosis, L-Selectin shedding and IL-8 production. aPL alone were only able to induce minor activation of PMN effector functions at high concentrations. However, in the additional presence of LPS the activation threshold was markedly lower indicating a synergistic activation pathway of aPL and TLR in PMN. In summary, our results indicate that PMN effector functions are directly activated by aPL and boosted by the additional presence of microbial products. This highlights a role for PMN as important innate immune effector cells that contribute to the pathophysiology of APS.

  13. Toll-like receptor-3 is dispensable for the innate microRNA response to West Nile virus (WNV.

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    Pauline E Chugh

    Full Text Available 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.

  14. Pathogen-mediated inflammatory atherosclerosis is mediated in part via Toll-like receptor 2-induced inflammatory responses.

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    Hayashi, Chie; Madrigal, Andres G; Liu, Xinyan; Ukai, Takashi; Goswami, Sulip; Gudino, Cynthia V; Gibson, Frank C; Genco, Caroline A

    2010-01-01

    Studies in humans have established that polymorphisms in genes encoding the innate immune Toll-like receptors (TLRs) are associated with inflammatory atherosclerosis. In hyperlipidemic mice, TLR2 and TLR4 have been reported to contribute to atherosclerosis progression. Human and mouse studies support a role for the oral pathogen Porphyromonas gingivalis in atherosclerosis, although the mechanisms by which this pathogen stimulates inflammatory atherosclerosis via innate immune system activation is not known. Using a genetically defined apolipoprotein E-deficient (ApoE(-/-)) mouse model we demonstrate that pathogen-mediated inflammatory atherosclerosis occurs via both TLR2-dependent and TLR2-independent mechanisms. P. gingivalis infection in mice possessing functional TLR2 induced the accumulation of macrophages as well as inflammatory mediators including CD40, IFN-gamma and the pro-inflammatory cytokines IL-1 beta, IL-6 and tumor necrosis factor-alpha in atherosclerotic lesions. The expression of these inflammatory mediators was reduced in atherosclerotic lesions from P. gingivalis-infected TLR2-deficient (TLR2(-/-)) mice. These studies provide a mechanistic link between an innate immune receptor and pathogen-accelerated atherosclerosis by a clinically and biologically relevant bacterial pathogen.

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

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    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.

  16. The broad pattern recognition spectrum of the Toll-like receptor in mollusk Zhikong scallop Chlamys farreri.

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    Wang, Mengqiang; Wang, Lingling; Guo, Ying; Sun, Rui; Yue, Feng; Yi, Qilin; Song, Linsheng

    2015-10-01

    Toll-like receptors (TLRs) are among the most studied pattern recognition receptors (PRRs) playing essential roles in innate immune defenses. In the present study, the basic features of CfTLR in mollusk Zhikong scallop Chlamys farreri, including sequence homology, tissue distribution, subcellular localization and ligands spectrum, were investigated to elucidate its pattern recognition. The elements of extracellular domains (ECD) in CfTLR displayed high homology to the corresponding parts of the ECDs in TLRs from Homo sapiens. CfTLR protein was detected in hemocytes, mantle, gills, hepatopancreas, kidney and gonad of the scallops, and it was localized in both the plasma membranes and the lysosomes in HEK293T cells. CfTLR could activate NFκB in response to multiple HsTLR ligands including Pam3CSK4, glucan (GLU), peptidoglycan (PGN), polyriboinosinic:polyribocytidylic acid (poly I:C), Imiquimod and three types of CpG. Additionally, the scallop serum could enhance the induction of NFκB in the CfTLR expressing cells elicited by most PAMPs, including GLU, PGN, Imiquimod and four types of CpG. It could be concluded that this primitive mollusk TLR shared a hybrid function in pattern recognition and could recognize broader ligands than mammalian TLRs, and its mosaic capability of pathogen associated molecular pattern (PAMP) recognition might be based on the basic features of its structure, ligand properties and the assistance of some components in scallop serum.

  17. Effects of human Toll-like receptor 1 polymorphisms on ageing

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    Uciechowski Peter

    2013-02-01

    Full Text Available Abstract Background Advanced age results in crucial alterations of the innate and adaptive immune system leading to functional defects resulting in infection and chronic diseases. Toll-like receptors (TLR recognize pathogenic structures and are important in the immune response to infections and vaccination. However, the role of TLR single nucleotide polymorphisms (SNP is poorly understood in the setting of human ageing. This study investigated the impact of the TLR1 SNPs A743G and T1805G on ageing in different age groups from two European populations. Results The TLR1 genotypes 743AA/1805GG (TLR1neg are associated with a TLR1 negative phenotype, impaired function and susceptibility to tuberculosis. Carriers of heterozygous 743AG/1805TG and homozygous 743GG/1805TT genotypes (TLR1pos have a TLR1 positive phenotype. By comparing healthy young and old German donors, the old group showed a tendency to carry more TLR1neg and less homozygous TLR1pos genotypes. Anti-inflammatory Interleukin (IL-1 receptor antagonist (Ra was significantly elevated in supernatants of mononuclear cells from old German subjects with a TLR1pos genotype in contrast to those with the 743AA genotype. Healthy old individuals and nonagenarians from Italy displayed significantly higher frequencies of TLR1pos genotypes than the old group from Germany. The data show that tumor-necrosis-factor (TNFα, CXCL8 and CCL2 levels were higher in old donors from Germany than in plasma levels from old Italian donors. TNFα and CCL2 levels were significantly raised in old German individuals compared to Italian nonagenarians. German and Italian donors with the TLR1neg genotype basically produced more CCL2 than older European donors with TLR1pos genotypes. Conclusion The higher frequency of the TLR1pos genotype in elderly Italian subjects may result from different ethnic populations. Lower inflammatory mediator release of aged Italian individuals is probably due to different background in

  18. Amino Acid-Dependent Attenuation of Toll-like Receptor Signaling by Peptide-Gold Nanoparticle Hybrids.

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    Yang, Hong; Fung, Shan-Yu; Xu, Shuyun; Sutherland, Darren P; Kollmann, Tobias R; Liu, Mingyao; Turvey, Stuart E

    2015-07-28

    Manipulation of immune responsiveness using nanodevices provides a potential approach to treat human diseases. Toll-like receptor (TLR) signaling plays a central role in the pathophysiology of many acute and chronic human inflammatory diseases, and pharmacological regulation of TLR responses is anticipated to be beneficial in many of these inflammatory conditions. Here we describe the discovery of a unique class of peptide-gold nanoparticle hybrids that exhibit a broad inhibitory activity on TLR signaling, inhibiting signaling through TLRs 2, 3, 4, and 5. As exemplified using TLR4, the nanoparticles were found to inhibit both arms of TLR4 signaling cascade triggered by the prototypical ligand, lipopolysaccharide (LPS). Through structure-activity relationship studies, we identified the key chemical components of the hybrids that contribute to their immunomodulatory activity. Specifically, the hydrophobicity and aromatic ring structure of the amino acids on the peptides were essential for modulating TLR4 responses. This work enhances our fundamental understanding of the role of nanoparticle surface chemistry in regulating innate immune signaling, and identifies specific nanoparticle hybrids that may represent a unique class of anti-inflammatory therapeutics for human inflammatory diseases.

  19. Expression of the Receptor Tyrosine Kinase EphB2 on Dendritic Cells Is Modulated by Toll-Like Receptor Ligation but Is Not Required for T Cell Activation.

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    Patrice N Mimche

    Full Text Available The Eph receptor tyrosine kinases interact with their ephrin ligands on adjacent cells to facilitate contact-dependent cell communication. Ephrin B ligands are expressed on T cells and have been suggested to act as co-stimulatory molecules during T cell activation. There are no detailed reports of the expression and modulation of EphB receptors on dendritic cells, the main antigen presenting cells that interact with T cells. Here we show that mouse splenic dendritic cells (DC and bone-marrow derived DCs (BMDC express EphB2, a member of the EphB family. EphB2 expression is modulated by ligation of TLR4 and TLR9 and also by interaction with ephrin B ligands. Co-localization of EphB2 with MHC-II is also consistent with a potential role in T cell activation. However, BMDCs derived from EphB2 deficient mice were able to present antigen in the context of MHC-II and produce T cell activating cytokines to the same extent as intact DCs. Collectively our data suggest that EphB2 may contribute to DC responses, but that EphB2 is not required for T cell activation. This result may have arisen because DCs express other members of the EphB receptor family, EphB3, EphB4 and EphB6, all of which can interact with ephrin B ligands, or because EphB2 may be playing a role in another aspect of DC biology such as migration.

  20. Downstream Toll-like receptor signaling mediates adaptor-specific cytokine expression following focal cerebral ischemia

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    Bolanle Famakin

    2012-07-01

    Full Text Available Abstract Background Deletion of some Toll-like receptors (TLRs affords protection against cerebral ischemia, but disruption of their known major downstream adaptors does not. To determine whether compensation in the production of downstream effectors by one pathway when the other is disrupted can explain these findings, we examined cytokine/chemokine expression and inflammatory infiltrates in wild-type (WT, MyD88−/− and TRIF-mutant mice following permanent middle cerebral artery occlusion (pMCAO. Methods Cytokine/chemokine expression was measured with a 25-plex bead array in the serum and brains of all three groups of mice at baseline (no surgery/naïve and at 3 hours and 24 hours following pMCAO. Brain inflammatory and neutrophil infiltrates were examined 24 hours following pMCAO. Results IL-6, keratinocyte chemoattractant (KC, granulocyte colony-stimulating factor (G-CSF and IL-10 were significantly decreased in MyD88−/− mice compared to WT mice following pMCAO. Significantly, decreased levels of the neutrophil chemoattractants KC and G-CSF corresponded with a trend toward fewer neutrophils in the brains of MyD88−/− mice. IP-10 was significantly decreased when either pathway was disrupted. MIP-1α was significantly decreased in TRIF-mutant mice, consistent with TRIF-dependent production. MyD88−/− mice showed elevations of a number of Th2 cytokines, such as IL-13, at baseline, which became significantly decreased following pMCAO. Conclusions Both MyD88 and TRIF mediate pathway-specific cytokine production following focal cerebral ischemia. Our results also suggest a compensatory Th2-type skew at baseline in MyD88−/− mice and a paradoxical switch to a Th1 phenotype following focal cerebral ischemia. The MyD88 pathway directs the expression of neutrophil chemoattractants following cerebral ischemia.

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

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    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.

  2. Toll-Like Receptor 9 Alternatively Spliced Isoform Negatively Regulates TLR9 Signaling in Teleost Fish

    Science.gov (United States)

    Chen, Nai-Yu; Nagarajan, Govindarajulu; Chiou, Pinwen Peter

    2015-01-01

    Toll-like receptor 9 (TLR9) recognizes and binds unmethylated CpG motifs in DNA, which are found in the genomes of bacteria and DNA viruses. In fish, Tlr9 is highly diverse, with the number of introns ranging from 0 to 4. A fish Tlr9 gene containing two introns has been reported to express two alternatively spliced isoforms, namely gTLR9A (full-length) and gTLR9B (with a truncated Cʹ-terminal signal transducing domain), whose regulation and function remain unclear. Here, we report a unique regulatory mechanism of gTLR9 signaling in orange-spotted grouper (Epinephelus coioides), whose gTlr9 sequence also contains two introns. We demonstrated that the grouper gTlr9 gene indeed has the capacity to produce two gTLR9 isoforms via alternative RNA splicing. We found that gTLR9B could function as a negative regulator to suppress gTLR9 signaling as demonstrated by the suppression of downstream gene expression. Following stimulation with CpG oligodeoxynucleotide (ODN), gTLR9A and gTLR9B were observed to translocate into endosomes and co-localize with ODN and the adaptor protein gMyD88. Both gTLR9A and gTLR9B could interact with gMyD88; however, gTLR9B could not interact with downstream IRAK4 and TRAF6. Further analysis of the expression profile of gTlr9A and gTlr9B upon immune-stimulation revealed that the two isoforms were differentially regulated in a time-dependent manner. Overall, these data suggest that fish TLR9B functions as a negative regulator, and that its temporal expression is mediated by alternative RNA splicing. This has not been observed in mammalian TLR9s and might have been acquired relatively recently in the evolution of fish. PMID:25955250

  3. Toll-Like Receptor 9 Alternatively Spliced Isoform Negatively Regulates TLR9 Signaling in Teleost Fish.

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    Frank Fang-Yao Lee

    Full Text Available Toll-like receptor 9 (TLR9 recognizes and binds unmethylated CpG motifs in DNA, which are found in the genomes of bacteria and DNA viruses. In fish, Tlr9 is highly diverse, with the number of introns ranging from 0 to 4. A fish Tlr9 gene containing two introns has been reported to express two alternatively spliced isoforms, namely gTLR9A (full-length and gTLR9B (with a truncated C'-terminal signal transducing domain, whose regulation and function remain unclear. Here, we report a unique regulatory mechanism of gTLR9 signaling in orange-spotted grouper (Epinephelus coioides, whose gTlr9 sequence also contains two introns. We demonstrated that the grouper gTlr9 gene indeed has the capacity to produce two gTLR9 isoforms via alternative RNA splicing. We found that gTLR9B could function as a negative regulator to suppress gTLR9 signaling as demonstrated by the suppression of downstream gene expression. Following stimulation with CpG oligodeoxynucleotide (ODN, gTLR9A and gTLR9B were observed to translocate into endosomes and co-localize with ODN and the adaptor protein gMyD88. Both gTLR9A and gTLR9B could interact with gMyD88; however, gTLR9B could not interact with downstream IRAK4 and TRAF6. Further analysis of the expression profile of gTlr9A and gTlr9B upon immune-stimulation revealed that the two isoforms were differentially regulated in a time-dependent manner. Overall, these data suggest that fish TLR9B functions as a negative regulator, and that its temporal expression is mediated by alternative RNA splicing. This has not been observed in mammalian TLR9s and might have been acquired relatively recently in the evolution of fish.

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

    Science.gov (United States)

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

    2016-04-01

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

  5. Toll-like receptor 4-dependent responses to lung injury in a murine model of pulmonary contusion.

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    Hoth, J Jason; Wells, Jonathan D; Brownlee, Noel A; Hiltbold, Elizabeth M; Meredith, J Wayne; McCall, Charles E; Yoza, Barbara K

    2009-04-01

    Blunt chest trauma resulting in pulmonary contusion with an accompanying acute inflammatory response is a common but poorly understood injury. We previously demonstrated that toll-like receptor 2 (TLR-2) participates in the inflammatory response to lung injury. We hypothesized that the TLR-4, in an MyD88-dependent manner, may also participate in the response to lung injury. To investigate this, we used a model of pulmonary contusion in the mouse that is similar to that observed clinically in humans and evaluated postinjury lung function, pulmonary neutrophil recruitment, and the systemic innate immune response. Comparisons were made between wild-type mice and mice deficient in TLR-4 or MyD88. We found TLR-4-dependent responses to pulmonary contusion that include hypoxemia, edema, and neutrophil infiltration. Increased expression of IL-6 and chemokine (C-X-C motif) ligand 1 in the bronchoalveolar lavage and serum was also dependent on TLR-4 activation. We further demonstrated that these responses to pulmonary contusion were dependent on MyD88, an adapter protein in the signal transduction pathway mediated by TLRs. These results show that TLRs have a primary role in the response to acute lung injury. Lung inflammation and systemic innate immune responses are dependent on TLR activation by pulmonary contusion.

  6. Toll-like receptor 4 mediates inflammatory cytokine secretion in smooth muscle cells induced by oxidized low-density lipoprotein.

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    Ke Yang

    Full Text Available Oxidized low-density lipoprotein (oxLDL-regulated secretion of inflammatory cytokines in smooth muscle cells (SMCs is regarded as an important step in the progression of atherosclerosis; however, its underlying mechanism remains unclear. This study investigated the role of toll-like receptor 4 (TLR4 in oxLDL-induced expression of inflammatory cytokines in SMCs both in vivo and in vitro. We found that the levels of TLR4, interleukin 1-β (IL1-β, tumor necrosis factor-α (TNFα, monocyte chemoattractant protein 1 (MCP-1 and matrix metalloproteinase-2 (MMP-2 expression were increased in the SMCs of atherosclerotic plaques in patients with femoral artery stenosis. In cultured primary arterial SMCs from wild type mice, oxLDL caused dose- and time-dependent increase in the expression levels of TLR4 and cytokines. These effects were significantly weakened in arterial SMCs derived from TLR4 knockout mice (TLR4-/-. Moreover, the secretion of inflammatory cytokines was blocked by TLR4-specific antibodies in primary SMCs. Ox-LDL induced activation of p38 and NFκB was also inhibited in TLR4-/- primary SMCs or when treated with TLR4-specific antibodies. These results demonstrated that TLR4 is a crucial mediator in oxLDL-induced inflammatory cytokine expression and secretion, and p38 and NFκB activation.

  7. Toll-Like Receptor Mediated Modulation of T Cell Response by Commensal Intestinal Microbiota as a Trigger for Autoimmune Arthritis

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    Rebecca Rogier

    2015-01-01

    Full Text Available In autoimmune diseases, a disturbance of the balance between T helper 17 (Th17 and regulatory T cells (Tregs is often observed. This disturbed balance is also the case in rheumatoid arthritis (RA. Genetic predisposition to RA confers the presence of several polymorphisms mainly regulating activation of T lymphocytes. However, the presence of susceptibility factors is neither necessary nor sufficient to explain the disease development, emphasizing the importance of environmental factors. Multiple studies have shown that commensal gut microbiota is of great influence on immune homeostasis and can trigger the development of autoimmune diseases by favoring induction of Th17 cells over Tregs. However the mechanism by which intestinal microbiota influences the Th cell balance is not completely understood. Here we review the current evidence supporting the involvement of commensal intestinal microbiota in rheumatoid arthritis, along with a potential role of Toll-like receptors (TLRs in modulating the relevant Th cell responses to trigger autoimmunity. A better understanding of TLR triggering by intestinal microbiota and subsequent T cell activation might offer new perspectives for manipulating the T cell response in RA patients and may lead to the discovery of new therapeutic targets or even preventive measures.

  8. The involvement of hypoxia-inducible factor 1 alpha in Toll-like receptor 7/8-mediated inflammatory response

    Institute of Scientific and Technical Information of China (English)

    Sally A Nicholas; Vadim V Sumbayev

    2009-01-01

    Toll-like receptors (TLRs) 7 and 8 are crucial in host defence against single-stranded RNA (ssRNA) viruses. Such viruses cause severe illnesses, which remain a serious medical burden in both industrialised and developing countries. TLR7/8 downstream signaling leads to a dramatic cellular stress associated with energy consumption. However, the molecular mechanisms of cell survival and adaptation to TLR7/8-induced stress, which give the cells an opportunity to initiate proper inflammatory reactions, are not clear at all. Here we report for the first time that ligand-induced ac-tivation of TLR7/8 leads to the accumulation of hypoxia-inducible factor 1 alpha (HIF-1α) protein in THP-1 human myeloid macrophages via redox-and reactive nitrogen species-dependent mechanisms. MAP kinases and phosphoi-nositol-3K are not involved in TLR7/8-mediated HIF-1α accumulation. Experiments with HIF-la knockdown THP-1 cells have clearly demonstrated that HIF-1α is important for the protection of these cells against TLR7/8-induced depletion of ATP. Thus, HIF-1α might support both cell survival and the production of pro-inflammatory cytokines upon TLR7/8 activation.

  9. Toll-Like Receptor 4 Deficiency Causes Reduced Exploratory Behavior in Mice Under Approach-Avoidance Conflict.

    Science.gov (United States)

    Li, Chunlu; Yan, Yixiu; Cheng, Jingjing; Xiao, Gang; Gu, Jueqing; Zhang, Luqi; Yuan, Siyu; Wang, Junlu; Shen, Yi; Zhou, Yu-Dong

    2016-04-01

    Abnormal approach-avoidance behavior has been linked to deficits in the mesolimbic dopamine (DA) system of the brain. Recently, increasing evidence has indicated that toll-like receptor 4 (TLR4), an important pattern-recognition receptor in the innate immune system, can be directly activated by substances of abuse, resulting in an increase of the extracellular DA level in the nucleus accumbens. We thus hypothesized that TLR4-dependent signaling might regulate approach-avoidance behavior. To test this hypothesis, we compared the novelty-seeking and social interaction behaviors of TLR4-deficient (TLR4(-/-)) and wild-type (WT) mice in an approach-avoidance conflict situation in which the positive motivation to explore a novel object or interact with an unfamiliar mouse was counteracted by the negative motivation to hide in exposed, large spaces. We found that TLR4(-/-) mice exhibited reduced novelty-seeking and social interaction in the large open spaces. In less stressful test apparatuses similar in size to the mouse cage, however, TLR4(-/-) mice performed normally in both novelty-seeking and social interaction tests. The reduced exploratory behaviors under approach-avoidance conflict were not due to a high anxiety level or an enhanced fear response in the TLR4(-/-) mice, as these mice showed normal anxiety and fear responses in the open field and passive avoidance tests, respectively. Importantly, the novelty-seeking behavior in the large open field induced a higher level of c-Fos activation in the nucleus accumbens shell (NAcSh) in TLR4(-/-) mice than in WT mice. Partially inactivating the NAcSh via infusion of GABA receptor agonists restored the novelty-seeking behavior of TLR4(-/-) mice. These data suggested that TLR4 is crucial for positive motivational behavior under approach-avoidance conflict. TLR4-dependent activation of neurons in the NAcSh may contribute to this phenomenon.

  10. How the Intricate Interaction among Toll-Like Receptors, Microbiota, and Intestinal Immunity Can Influence Gastrointestinal Pathology.

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    Frosali, Simona; Pagliari, Danilo; Gambassi, Giovanni; Landolfi, Raffaele; Pandolfi, Franco; Cianci, Rossella

    2015-01-01

    The gut is able to maintain tolerance to microbial and food antigens. The intestine minimizes the number of harmful bacteria by shaping the microbiota through a symbiotic relationship. In healthy human intestine, a constant homeostasis is maintained by the perfect regulation of microbial load and the immune response generated against it. Failure of this balance may result in various pathological conditions. Innate immune sensors, such as Toll-like receptors (TLRs), may be considered an interface among intestinal epithelial barrier, microbiota, and immune system. TLRs pathway, activated by pathogens, is involved in the pathogenesis of several infectious and inflammatory diseases. The alteration of the homeostasis between physiologic and pathogenic bacteria of intestinal flora causes a condition called dysbiosis. The breakdown of homeostasis by dysbiosis may increase susceptibility to inflammatory bowel diseases. It is evident that environment, genetics, and host immunity form a highly interactive regulatory triad that controls TLR function. Imbalanced relationships within this triad may promote aberrant TLR signaling, critically contributing to acute and chronic intestinal inflammatory processes, such as in IBD, colitis, and colorectal cancer. The study of interactions between different components of the immune systems and intestinal microbiota will open new horizons in the knowledge of gut inflammation.

  11. How the Intricate Interaction among Toll-Like Receptors, Microbiota, and Intestinal Immunity Can Influence Gastrointestinal Pathology

    Directory of Open Access Journals (Sweden)

    Simona Frosali

    2015-01-01

    Full Text Available The gut is able to maintain tolerance to microbial and food antigens. The intestine minimizes the number of harmful bacteria by shaping the microbiota through a symbiotic relationship. In healthy human intestine, a constant homeostasis is maintained by the perfect regulation of microbial load and the immune response generated against it. Failure of this balance may result in various pathological conditions. Innate immune sensors, such as Toll-like receptors (TLRs, may be considered an interface among intestinal epithelial barrier, microbiota, and immune system. TLRs pathway, activated by pathogens, is involved in the pathogenesis of several infectious and inflammatory diseases. The alteration of the homeostasis between physiologic and pathogenic bacteria of intestinal flora causes a condition called dysbiosis. The breakdown of homeostasis by dysbiosis may increase susceptibility to inflammatory bowel diseases. It is evident that environment, genetics, and host immunity form a highly interactive regulatory triad that controls TLR function. Imbalanced relationships within this triad may promote aberrant TLR signaling, critically contributing to acute and chronic intestinal inflammatory processes, such as in IBD, colitis, and colorectal cancer. The study of interactions between different components of the immune systems and intestinal microbiota will open new horizons in the knowledge of gut inflammation.

  12. Role of Cytokines and Toll-Like Receptors in the Immunopathogenesis of Guillain-Barré Syndrome

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    Kishan Kumar Nyati

    2014-01-01

    Full Text Available Guillain-Barré syndrome (GBS is an autoimmune disease of the peripheral nervous system, mostly triggered by an aberrant immune response to an infectious pathogen. Although several infections have been implicated in the pathogenesis of GBS, not all such infected individuals develop this disease. Moreover, infection with a single agent might also lead to different subtypes of GBS emphasizing the role of host factors in the development of GBS. The host factors regulate a broad range of inflammatory processes that are involved in the pathogenesis of autoimmune diseases including GBS. Evidences suggest that systemically and locally released cytokines and their involvement in immune-mediated demyelination and axonal damage of peripheral nerves are important in the pathogenesis of GBS. Toll-like receptors (TLRs link innate and adaptive immunity through transcription of several proinflammatory cytokines. TLR genes may increase susceptibility to microbial infections; an attenuated immune response towards antigen and downregulation of cytokines occurs due to mutation in the gene. Herein, we discuss the crucial role of host factors such as cytokines and TLRs that activate the immune response and are involved in the pathogenesis of the disease.

  13. Shockwave therapy differentially stimulates endothelial cells: implications on the control of inflammation via toll-Like receptor 3.

    Science.gov (United States)

    Holfeld, Johannes; Tepeköylü, Can; Kozaryn, Radoslaw; Urbschat, Anja; Zacharowski, Kai; Grimm, Michael; Paulus, Patrick

    2014-02-01

    Shock wave therapy (SWT) reportedly improves ventricular function in ischemic heart failure. Angiogenesis and inflammation modulatory effects were described. However, the mechanism remains largely unknown. We hypothesized that SWT modulates inflammation via toll-like receptor 3 (TLR3) through the release of cytosolic RNA. SWT was applied to human umbilical vein endothelial cells (HUVECs) with 250 impulses, 0.08 mJ/mm(2) and 3 Hz. Gene expression of TLR3, inflammatory genes and signalling molecules was analysed at different time points by real-time polymerase chain reaction. SWT showed activation of HUVECs: enhanced expression of TLR3 and of the transporter protein for nucleic acids cyclophilin B, of pro-inflammatory cytokines cyclophilin A and interleukin-6 and of anti-inflammatory interleukin-10. No changes were found in the expression of vascular endothelial cell adhesion molecule. SWT modulates inflammation via the TLR3 pathway. The interaction between interleukin (IL)-6 and IL-10 in TLR3 stimulation can be schematically seen as a three-phase regulation over time.

  14. A toll-like receptor 2-responsive lipid effector pathway protects mammals against skin infections with gram-positive bacteria.

    Science.gov (United States)

    Georgel, Philippe; Crozat, Karine; Lauth, Xavier; Makrantonaki, Evgenia; Seltmann, Holger; Sovath, Sosathya; Hoebe, Kasper; Du, Xin; Rutschmann, Sophie; Jiang, Zhengfan; Bigby, Timothy; Nizet, Victor; Zouboulis, Christos C; Beutler, Bruce

    2005-08-01

    flake (flk), an N-ethyl-N-nitrosourea-induced recessive germ line mutation of C57BL/6 mice, impairs the clearance of skin infections by Streptococcus pyogenes and Staphylococcus aureus, gram-positive pathogens that elicit innate immune responses by activating Toll-like receptor 2 (TLR2). Positional cloning and sequencing revealed that flk is a novel allele of the stearoyl coenzyme A desaturase 1 gene (Scd1). flake homozygotes show reduced sebum production and are unable to synthesize the monounsaturated fatty acids (MUFA) palmitoleate (C(16:1)) and oleate (C(18:1)), both of which are bactericidal against gram-positive (but not gram-negative) organisms in vitro. However, intradermal MUFA administration to S. aureus-infected mice partially rescues the flake phenotype, which indicates that an additional component of the sebum may be required to improve bacterial clearance. In normal mice, transcription of Scd1-a gene with numerous NF-kappaB elements in its promoter--is strongly and specifically induced by TLR2 signaling. Similarly, the SCD1 gene is induced by TLR2 signaling in a human sebocyte cell line. These observations reveal the existence of a regulated, lipid-based antimicrobial effector pathway in mammals and suggest new approaches to the treatment or prevention of infections with gram-positive bacteria.

  15. Elevated expression of the toll like receptors 2 and 4 in obese individuals: its significance for obesity-induced inflammation

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    Ahmad Rasheed

    2012-11-01

    Full Text Available Abstract Background Expression profile of the toll like receptors (TLRs on PBMCs is central to the regulation of proinflammatory markers. An imbalance in the TLRs expression may lead to several types of inflammatory disorders. Furthermore, the dynamic regulation of inflammatory activity and associated impaired production of cytokines by peripheral blood mononuclear cells (PBMCs in obese individulas remain poorly understood. Therefore, we determined the perturbation in TLRs (TLR2 and TLR4, their adaptor proteins (MyD88, IRAK1 and TRAF6 expression in PBMCs/subcutaneous adipose tissue (AT as well as inflammatory cytokines changes in obese individuals. Methods mRNA expression levels of TLR2, TLR4, IL-6, TNF-α and adaptor proteins were determined by RT-PCR. TLR2, TLR4 and adaptor proteins expression in AT was determined by immunohistochemistry. Results Obese and overweight individuals showed significantly increased expression of TLR2, TLR4 and MyD88 in both PBMCs and AT as compared with lean individuals (P  Conclusions TLRs and adapter proteins were overexpressed in PBMCs from obese subjects, which correlated with increased expression of TNF-α and IL-6. This association may explain a potential pathophysiological link between obesity and inflammation leading to insulin resistance.

  16. Cultured Mesenchymal Stem Cells Stimulate an Immune Response by Providing Immune Cells with Toll-Like Receptor 2 Ligand.

    Science.gov (United States)

    Weinstock, Ada; Pevsner-Fischer, Meirav; Porat, Ziv; Selitrennik, Michael; Zipori, Dov

    2015-12-01

    Mesenchymal stem cells (MSCs) serve as supporting and regulatory cells, by providing tissues with multiple factors and are also known for their immunosuppressive capabilities. Our laboratory had previously shown that MSCs expressed toll-like receptor (TLR) 2 and are activated by its ligand Pam3Cys. TLR2 is an important component of the innate immune system, as it recognizes bacterial lipopeptides, thus priming a pro-inflammatory immune response. This study showed that Pam3Cys attached extensively to cells of both wild-type and TLR2 deficient cultured MSCs, thus, independently of TLR2. The TLR2 independent binding occurred through the adsorption of the palmitoyl moieties of Pam3Cys. It was further showed that Pam3Cys was transferred from cultured MSCs to immune cells. Moreover, Pam3Cys provided to the immune cells induced a pro-inflammatory response in vitro and in vivo. Overall, it is demonstrated herein that a TLR2 ligand bound to MSCs also through a TLR2 independent mechanism. Furthermore, the ligand incorporated by MSCs is subsequently released to stimulate an immune response both in vitro and in vivo. It is thus suggested that during bacterial infection, stromal cells may retain a reservoir of the TLR2 ligands, in a long-term manner, and release them slowly to maintain an immune response.

  17. TAK1 contributes to the enhanced responsiveness of LTB(4)-treated neutrophils to Toll-like receptor ligands.

    Science.gov (United States)

    Gaudreault, Éric; Paquet-Bouchard, Carine; Fiola, Stéphanie; Le Bel, Manon; Lacerte, Patricia; Shio, Marina Tiemi; Olivier, Martin; Gosselin, Jean

    2012-11-01

    Pattern-recognition receptors such as Toll-like receptors (TLRs) are essential sensors implicated in the early and efficient innate immune response against pathogens. We have previously demonstrated that leukotriene B(4)(LTB(4)) has the capacity to enhance leukocyte responses to TLR9 ligands and to control viral infection. In this report, we provide evidence that LTB(4) treatment of human neutrophils leads to a potentiation in proinflammatory cytokine secretion induced by various myeloid differentiation factor 88-dependent TLR agonists. LTB(4) failed to enhance TLR mRNA levels as well as expression of TLR2 and TLR4 receptors, suggesting that LTB(4) acts through intracellular mechanism(s) to potentiate neutrophil responses to TLR ligands. We found that while IRAK can be activated by LTB(4), this process is dispensable to LTB(4) to potentiate neutrophil responses to TLR ligands since pretreatment of neutrophils with IRAK1/4 inhibitor did not affect its potentiating effects. However, our data clearly show that LTB(4) treatment of neutrophils led to the phosphorylation of downstream signaling molecules, TAK1 and p38, a process found essential to observe an increased secretion of cytokines by neutrophils activated with TLR ligands. Pretreatment of neutrophils with TAK1 or p38 kinase inhibitors strongly repressed the effect of LTB(4) on cytokine synthesis by neutrophils stimulated with LTA, LPS or CpG. The same pattern was observed in agonist-treated human embryonic kidney 293 cells transfected with TAK1-targeting siRNA where secretion of IL-8 was significantly reduced to basal levels. These results indicate that TAK1 and p38 kinases appear to be central in the 'priming effect' of LTB(4) on neutrophils to enhance response to TLR ligands.

  18. Toll-like receptor 9 mediates oral bacteria-induced IL-8 expression in gingival epithelial cells.

    Science.gov (United States)

    Kim, Youngsook; Jo, Ah-ram; Jang, Da Hyun; Cho, Yong-Joon; Chun, Jongsik; Min, Byung-Moo; Choi, Youngnim

    2012-07-01

    Previously, we reported that various oral bacteria regulate interleukin (IL)-8 production differently in gingival epithelial cells. The aim of this study was to characterize the pattern recognition receptor(s) that mediate bacteria-induced IL-8 expression. Among ligands that mimic bacterial components, only a Toll-like receptor (TLR) 9 ligand enhanced IL-8 expression as determined by ELISA. Both normal and immortalized human gingival epithelial (HOK-16B) cells expressed TLR9 intracellularly and showed enhanced IL-8 expression in response to CpG-oligonucleotide. The ability of eight strains of four oral bacterial species to induce IL-8 expression in HOK-16B cells, and their invasion capacity were examined in the absence or presence of 2% human serum. The ability of purified bacterial DNA (bDNA) to induce IL-8 was also examined. Six out of eight strains increased IL-8 production in the absence of serum. Usage of an endosomal acidification blocker or a TLR9 antagonist inhibited the IL-8 induction by two potent strains. In the presence of serum, many strains lost the ability to induce IL-8 and presented substantially reduced invasion capacity. The IL-8-inducing ability of bacteria in the absence or presence of serum showed a strong positive correlation with their invasion index. The IL-8-inducing ability of bacteria in the absence of human serum was also correlated with the immunostimulatory activity of its bDNA. The observed immunostimulatory activity of the bDNA could not be linked to its CpG motif content. In conclusion, oral bacteria induce IL-8 in gingival epithelial cells through TLR9 and the IL-8-inducing ability depends on the invasive capacity and immunostimulating DNA.

  19. MiRNA-194 Regulates Palmitic Acid-Induced Toll-Like Receptor 4 Inflammatory Responses in THP-1 Cells.

    Science.gov (United States)

    Tian, Huiqun; Liu, Chaoqi; Zou, Xiaohua; Wu, Wei; Zhang, Changcheng; Yuan, Ding

    2015-05-13

    There is strong evidence to suggest that inflammatory responses link obesity and diseases, and the understanding of obesity-induced inflammatory mechanisms is central to the pathogenesis of diseases such asnonalcoholic fatty liver disease(NAFLD) and atherosclerosis that are modified by obesity. Based on this, anti-inflammatory treatments become a potential therapies for obesity-related diseases like NAFLD.A critical role of toll-like receptor (TLR) and its downstream molecules such as tumor necrosis factor receptor-associated factor 6(TRAF6) has been documented in inflammatory response induced by fatty acid. TLR pathway regulation provides a new insight to controlling the inflammatory response induced by fatty acid. Taken together, our study was aimed to understand the mechanism of fatty acid-mediated inflammation and look for an effective target which can prevent the inflammatory response induced by obesity. In this study, we used the saturated fatty acid palmitic acid (PA) to activate TLR4 signal pathway in human monocyte cells THP-1 that established an intracellular inflammatory model. Followed with activated TLR4, downstream molecular TRAF6 was upregulated and ultimately induced proinflammatory cytokine production. Based on this model, we also found that PA downregulated miR-194 expression with TLR4 activation. Moreover, our results showed that key signal molecular TRAF6 is a target of miR-194, overexpression of miR-194 directly decreased TRAF6 expression and attenuated the release of proinflammatory cytokine TNF-α in PA-activated monocyte THP-1. We conclude that miR-194 negatively regulates the TLR4 signal pathway which is activated by PA through directly negative TRAF6 expression.

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

    Science.gov (United States)

    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

  1. 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.

    Science.gov (United States)

    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

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

    Science.gov (United States)

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

    2014-05-01

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

  3. DMPD: Toll-like receptor signal transduction. [Dynamic Macrophage Pathway CSML Database

    Lifescience Database Archive (English)

    Full Text Available (4):421-38. Pathway - PNG File (.png) SVG File (.svg) HTML File (.html) CSML File (.csml) Open .csml file with CIOPlayer Open .csm... M, Lee G, Choi S. Exp Mol Med. 2007 Aug 31;39(4):421-38. (.png) (.svg) (.html) (.csml) Show Toll-like recep...l file with CIOPlayer - ※CIO Playerのご利用上の注意 Open .csml file with CIO Open .csml file with CIO - ※CIOのご利用上の注意 ...

  4. Interrelationship of dendritic cells, type 1 interferon system, regulatory T cells and toll-like receptors and their role in lichen planus and lupus erythematosus -- a literature review.

    Science.gov (United States)

    Trucci, Victoria Martina; Salum, Fernanda Gonçalves; Figueiredo, Maria Antonia; Cherubini, Karen

    2013-10-01

    There is evidence that the activation of some receptors of the toll-like family (TLRs) of the innate immune system, and also changes in expression levels of forkhead box p3 (Foxp3) protein, which is found in regulatory T cells (Tregs), could be involved in the development of autoimmunity. We present here a literature review focusing on the interrelationship of dendritic cells, TLRs, Tregs and type 1 interferon in autoimmune diseases, with special interest in lichen planus and lupus erythematosus. Understanding the specific role of each of these factors would help elucidate the obscure aetiology of such diseases and open new perspectives for their management and treatment.

  5. Characterization and functional analysis of toll-like receptor 4 in Chinese soft-shelled turtle Pelodiscus sinensis.

    Science.gov (United States)

    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.

  6. Cancers take their Toll--the function and regulation of Toll-like receptors in cancer cells

    DEFF Research Database (Denmark)

    Chen, R; Alvero, A B; Silasi, D-A

    2008-01-01

    Cancer could be deemed as an abnormal and uncontrolled tissue repair process. Therefore, it would not be surprising that factors that function in the tissue repair process, such as cytokines, chemokines, growth factors and Toll-like receptor (TLR) ligands, as well as growth signals for compensatory...... proliferation, would also be key factors in regulating and enhancing cancer progression. The TLR pathways, which play a critical role in tissue repair, are also key regulators in cancer progression as well as chemoresistance. TLRs serve as cell surface sensors that can initiate pathways leading to proliferation...

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

    Science.gov (United States)

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

    2015-01-01

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

  8. Human but not murine toll-like receptor 2 discriminates between tri-palmitoylated and tri-lauroylated peptides.

    Science.gov (United States)

    Grabiec, Alina; Meng, Guangxun; Fichte, Sylvia; Bessler, Wolfgang; Wagner, Hermann; Kirschning, Carsten J

    2004-11-12

    Toll-like receptors (TLRs) mediate activation of the immune system upon challenge with microbial agonists, components of disintegrating cells of the body, or metabolic intermediates of lipidic nature. Comparison of murine (m) and human (h) TLR2 primary sequences revealed 65% of identical residues within the extracellular domains in contrast to 84% in the intracellular domains. Comparative analysis of TLR2-driven cell activation by various TLR2 agonists showed that the tri-lauroylated lipopeptide analog (Lau(3)CSK(4)) is recognized efficiently through mTLR2 but not hTLR2. Genetically complemented human embryonic kidney 293 cells and murine TLR2(-/-) embryonic fibroblasts, as well as human and murine macrophage cells, were used for this analysis. In contrast to cellular activation, which depended on blockable access of the TLR2-ligand to TLR2, cellular uptake of Lau(3)CSK(4) and tri-palmitoylated peptide (P(3)CSK(4)) was independent of TLR2. A low-conserved region spanning from leucine-rich repeat (LRR) motif 7 to 10 was found to control TLR2 species-specific cell activation. Exchange of mLRR8 for hLRR8 in mTLR2 abrogated mTLR2-typical cell activation upon cellular challenge with Lau(3)CSK(4) but not P(3)CSK(4), implicating mLRR8 as a central element of Lau(3)CSK(4) recognition. The point mutation L112P within LRR3 abrogated hTLR2-dependent recognition of lipopeptides but merely attenuated mTLR2 function, whereas deletion of the N-terminal third of each LRR-rich domain (LRRs 1 to 7) had the opposite effect on P(3)CSK(4) recognition. Despite similar domain structure of both TLR2 molecules, species-specific properties thus exist. Our results imply distinct susceptibilities of humans and mice to challenge with specific TLR2 ligands.

  9. Extracellular heat-shock protein 70 aggravates cerulein-induced pancreatitis through toll-like receptor-4 in mice

    Institute of Scientific and Technical Information of China (English)

    SONG Jun-min; WANG Rong; LIU Hong-xiang; LI Yuan; ZENG Yu-jian; ZHOU Zong-guang; LIU Hai-yi; XU Bing; WANG Ling; ZHOU Bin

    2008-01-01

    Background In patients suffering from acute pancreatitis, the pathogenesis is not completely understood, and several recent studies in vitro suggested that heat shock proteins might play an important role in cell signaling. To investigate the possible role of extracellular heat shock protein 70 (Hsp70) in pancreatitis, toll-like receptor-4 (TLR4)-deficient and wild-type mice were administered with exogenous Hsp70 during the course of cerulein-induced pancreatitis (CIP).Methods Acute pancreatitis was induced by 5 intraperitoneal injections of cerulein at hourly intervals, and then treated with recombinant Hsp70 through the caudal vein 4 hours after the start of cerulein injections. Subsequently serum amylase and serum cytokines levels were detected. Histologic alteration of the pancreas was evaluated. Tumor necrosis factor alpha (TNF-a) concentrations and myeloperoxidase (MPO) activity in both pancreas and lungs were analyzed. The nuclear factor kappa B (NF-KB) activation in pancreatic tissue was measured using a sensitive RelA enzyme-linked immunosorbent assay.Results Treatment with recombinant Hsp70 to wild-type mice in CIP resulted in significant aggravation of inflammation in pancreas, elevated levels of serum cytokines, up-regulation of pulmonary MPO activity and increase of lung tissues TNF-α concentrations. In contrast, treatment with Hsp70 to TLR4-deficient mice had little effect on serum cytokines levels, pancreatic inflammation, pulmonary MPO activity and TNF-a concentrations.Conclusions The results suggest that extracellular HspTO might induce systemic inflammatory response syndrome (SIRS)-Iike response in vivo and TLR4 might be involved in the Hsp70-mediated activation of inflammatory reaction in the progression of CIP without infection.

  10. Toll-like receptor 3 agonist Poly I:C protects against simulated cerebral ischemia in vitro and in vivo

    Institute of Scientific and Technical Information of China (English)

    Lin-na PAN; Wei ZHU; Cai LI; Xu-lin XU; Lian-jun GUO; Qing LU

    2012-01-01

    Aim:To examine the neuroprotective effects of the Toll-like receptor 3 (TLR3) agonist Poly I:C in acute ischemic models in vitro and in vivo.Methods:Primary astrocyte cultures subjected to oxygen-glucose deprivation (OGD) were used as an in vitro simulated ischemic model.Poly I:C was administrated 2 h before OGD.Cell toxicity was measured using MTT assay and LDH leakage assay.The levels of TNFα,IL-6 and interferon-β (IFNβ) in the media were measured using ELISA.Toll/interleukin receptor domain-containing adaptor-inducing IFNβ (TRIF) protein levels were detected using Western blot analysis.A mouse middle cerebral artery occlusion (MCAO) model was used for in vivo study.The animals were administered Poly I:C (0.3 mg/kg,im) 2 h before MCAO,and examined with neurological deficit scoring and TTC staining.The levels of TNFα and IL-6 in ischemic brain were measured using ELISA.Results:Pretreatment with Poly I:C (10 and 20 μg/mL) markedly attenuated OGD-induced astrocyte injury,and significantly raised the cell viability and reduced the LDH leakage.Poly I:C significantly upregulated TRIF expression accompanied by increased downstream IFNβ production.Moreover,Poly I:C significantly suppressed the pro-inflammatory cytokines TNFα and IL-6 production.In mice subjected to MCAO,administration of Poly I:C significantly attenuated the neurological deficits,reduced infarction volume,and suppressed the increased levels of TNFα and IL-6 in the ischemic striatum and cortex.Conclusion:Poly I:C pretreatment exerts neuroprotective and anti-inflammatory effects in the simulated cerebral ischemia models,and the neuroprotection is at least in part due to the activation of the TLR3-TRIF pathway.

  11. Comparative analysis of species-specific ligand recognition in Toll-like receptor 8 signaling: a hypothesis.

    Directory of Open Access Journals (Sweden)

    Rajiv Gandhi Govindaraj

    Full Text Available Toll-like receptors (TLRs play a central role in the innate immune response by recognizing conserved structural patterns in a variety of microbes. TLRs are classified into six families, of which TLR7 family members include TLR7, 8, and 9, which are localized to endolysosomal compartments recognizing viral infection in the form of foreign nucleic acids. In our current study, we focused on TLR8, which has been shown to recognize different types of ligands such as viral or bacterial ssRNA as well as small synthetic molecules. The primary sequences of rodent and non-rodent TLR8s are similar, but the antiviral compound (R848 that activates the TLR8 pathway is species-specific. Moreover, the factors underlying the receptor's species-specificity remain unknown. To this end, comparative homology modeling, molecular dynamics simulations refinement, automated docking and computational mutagenesis studies were employed to probe the intermolecular interactions between this anti-viral compound and TLR8. Furthermore, comparative analyses of modeled TLR8 (rodent and non-rodent structures have shown that the variation mainly occurs at LRR14-15 (undefined region; hence, we hypothesized that this variation may be the primary reason for the exhibited species-specificity. Our hypothesis was further bolstered by our docking studies, which clearly showed that this undefined region was in close proximity to the ligand-binding site and thus may play a key role in ligand recognition. In addition, the interface between the ligand and TLR8s varied depending upon the amino acid charges, free energy of binding, and interaction surface. Therefore, our current work provides a hypothesis for previous in vivo studies in the context of TLR signaling.

  12. Origin and consequences of brain Toll-like receptor 4 pathway stimulation in an experimental model of depression

    Directory of Open Access Journals (Sweden)

    Madrigal José LM

    2011-11-01

    Full Text Available Abstract Background There is a pressing need to identify novel pathophysiological pathways relevant to depression that can help to reveal targets for the development of new medications. Toll-like receptor 4 (TLR-4 has a regulatory role in the brain's response to stress. Psychological stress may compromise the intestinal barrier, and increased gastrointestinal permeability with translocation of lipopolysaccharide (LPS from Gram-negative bacteria may play a role in the pathophysiology of major depression. Methods Adult male Sprague-Dawley rats were subjected to chronic mild stress (CMS or CMS+intestinal antibiotic decontamination (CMS+ATB protocols. Levels of components of the TLR-4 signaling pathway, of LPS and of different inflammatory, oxidative/nitrosative and anti-inflammatory mediators were measured by RT-PCR, western blot and/or ELISA in brain prefrontal cortex. Behavioral despair was studied using Porsolt's test. Results CMS increased levels of TLR-4 and its co-receptor MD-2 in brain as well as LPS and LPS-binding protein in plasma. In addition, CMS also increased interleukin (IL-1β, COX-2, PGE2 and lipid peroxidation levels and reduced levels of the anti-inflammatory prostaglandin 15d-PGJ2 in brain tissue. Intestinal decontamination reduced brain levels of the pro-inflammatory parameters and increased 15d-PGJ2, however this did not affect depressive-like behavior induced by CMS. Conclusions Our results suggest that LPS from bacterial translocation is responsible, at least in part, for the TLR-4 activation found in brain after CMS, which leads to release of inflammatory mediators in the CNS. The use of Gram-negative antibiotics offers a potential therapeutic approach for the adjuvant treatment of depression.

  13. ROLE OF TOLL-LIKE RECEPTOR 4 IN AIRWAY INFLAMMA-TION OF CHRONIC OBSTRUCTIVE PULMONARY DISEASES

    Institute of Scientific and Technical Information of China (English)

    ZHOU Min; RONG Xia-jun; WAN Huan-ying; HUANG Shao-guang; LI Biao; LI Min

    2008-01-01

    Objective To confirm if pulmonary epithelial cells express Toll-like receptor 4 (TLR4) and investigate the role of TLR4 in airway inflammation of chronic obstructive pulmonary diseases (COPD). Methods The expressions of TLR4, IL-8 mRNA and NF-κB activation stimulated by differen factors [lipopolysacharides (LPS), interleukin-1β, cigarette smoking extract (CSE)] in pulmonary epithelial cells were investigated. Results LPS, CSE and IL-1β induced the production of IL-8 and activation of NF-κB. The levels of IL-8 mRNA and NF-κB protein in ElA+ cell were markedly higher than ElA-cell and A549 cell (P<0.05). The TLR4 mRNA of all the cells increased along with the increase of LPS' stimulated time. There was significant difference among different LPS' doses (12 h: P=0.039; 24 h: P=0.013). The TLR4 mRNA of ElA+ cell was higher than the other two groups (P<0.05). IL-1β induced all the cells expressing TLR4 mRNA. CSE had no effect on the expression of TLR4 mRNA. Conclusion Pulmonary epithelial cells express TLR4. LPS and IL-1β up-regulate IL-8 mediated via the activation of NF-κB induced by TLR4. But CSE up-regulates IL-8 mediated via the activation of NF-κB, which has no relation to TLR4 and may have another signal transduction pathway.

  14. Chronic treatment with metformin suppresses toll-like receptor 4 signaling and attenuates left ventricular dysfunction following myocardial infarction.

    Science.gov (United States)

    Soraya, Hamid; Clanachan, Alexander S; Rameshrad, Maryam; Maleki-Dizaji, Nasrin; Ghazi-Khansari, Mahmoud; Garjani, Alireza

    2014-08-15

    Acute treatment with metformin has a protective effect in myocardial infarction by suppression of inflammatory responses due to activation of AMP-activated protein kinase (AMPK). In the present study, the effect of chronic pre-treatment with metformin on cardiac dysfunction and toll-like receptor 4 (TLR4) activities following myocardial infarction and their relation with AMPK were assessed. Male Wistar rats were randomly assigned to one of 5 groups (n=6): normal control and groups were injected isoproterenol after chronic pre-treatment with 0, 25, 50, or 100mg/kg of metformin twice daily for 14 days. Isoproterenol (100mg/kg) was injected subcutaneously on the 13th and 14th days to induce acute myocardial infarction. Isoproterenol alone decreased left ventricular systolic pressure and myocardial contractility indexed as LVdp/dtmax and LVdp/dtmin. The left ventricular dysfunction was significantly lower in the groups treated with 25 and 50mg/kg of metformin. Metfromin markedly lowered isoproterenol-induced elevation in the levels of TLR4 mRNA, myeloid differentiation protein 88 (MyD88), tumor necrosis factor-alpha (TNF-α), and interleukin 6 (IL-6) in the heart tissues. Similar changes were also seen in the serum levels of TNF-α and IL-6. However, the lower doses of 25 and 50mg/kg were more effective than 100mg/kg. Phosphorylated AMPKα (p-AMPK) in the myocardium was significantly elevated by 25mg/kg of metformin, slightly by 50mg/kg, but not by 100mg/kg. Chronic pre-treatment with metformin reduces post-myocardial infarction cardiac dysfunction and suppresses inflammatory responses, possibly through inhibition of TLR4 activities. This mechanism can be considered as a target to protect infarcted myocardium.

  15. Curcumin Modulates Macrophage Polarization Through the Inhibition of the Toll-Like Receptor 4 Expression and its Signaling Pathways

    Directory of Open Access Journals (Sweden)

    Yaoyao Zhou

    2015-05-01

    Full Text Available Background: Curcumin, the active ingredient in curcuma rhizomes, has a wide range of therapeutic effects. However, its atheroprotective activity in human acute monocytic leukemia THP-1 cells remains unclear. We investigated the activity and molecular mechanism of action of curcumin in polarized macrophages. Methods: Phorbol myristate acetate (PMA-treated THP-1 cells were differentiated to macrophages, which were further polarized to M1 cells by lipopolysaccharide (LPS; 1 µg/ml and interferon (IFN-γ (20 ng/ml and treated with varying curcumin concentrations. [3H]thymidine (3H-TdR incorporation assays were utilized to measure curcumin-induced growth inhibition. The expression of tumor necrosis factor-a (TNF-a, interleukin (IL-6, and IL-12B (p40 were measured by quantitative real-time polymerase chain reaction (PCR and enzyme-linked immunosorbent assay (ELISA. Macrophage polarization and its mechanism were evaluated by flow cytometry and western blot. Additionally, toll-like receptor 4 (TLR4 small interfering RNA and mitogen-activated protein kinase (MAPK inhibitors were used to further confirm the molecular mechanism of curcumin on macrophage polarization. Results: Curcumin dose-dependently inhibited M1 macrophage polarization and the production of TNF-a, IL-6, and IL-12B (p40. It also decreased TLR4 expression, which regulates M1 macrophage polarization. Furthermore, curcumin significantly inhibited the phosphorylation of ERK, JNK, p38, and nuclear factor (NF-γB. In contrast, SiTLR4 in combination with p-JNK, p-ERK, and p-p38 inhibition reduced the effect of curcumin on polarization. Conclusions: Curcumin can modulate macrophage polarization through TLR4-mediated signaling pathway inhibition, indicating that its effect on macrophage polarization is related to its anti-inflammatory and atheroprotective effects. Our data suggest that curcumin could be used as a therapeutic agent in atherosclerosis.

  16. Hepatitis C virus core protein induces fibrogenic actions of hepatic stellate cells via toll-like receptor 2.

    Science.gov (United States)

    Coenen, Martin; Nischalke, Hans Dieter; Krämer, Benjamin; Langhans, Bettina; Glässner, Andreas; Schulte, Daniela; Körner, Christian; Sauerbruch, Tilman; Nattermann, Jacob; Spengler, Ulrich

    2011-09-01

    Hepatic stellate cells (HSCs) represent the main fibrogenic cell type accumulating extracellular matrix in the liver. Recent data suggest that hepatitis C virus (HCV) core protein may directly activate HSCs. Therefore, we examined the influence of recombinant HCV core protein on human HSCs. Primary human HSCs and the human HSC line LX-2 were stimulated with recombinant HCV proteins core and envelope 2 protein. Expression of procollagen type I α-1, α-smooth muscle actin, cysteine- and glycine-rich protein 2, glial fibrillary acidic protein, tissue growth factor β1, matrix metalloproteinases 2 (MMP2) and 13, tissue inhibitor of metalloproteinases 1 and 2 was investigated by real-time PCR. Intracellular signaling pathways of ERK1/2, p38 and, jun-amino-terminal kinase (JNK) were analyzed by western blot analysis. Recombinant HCV core protein induced upregulation of procollagen type I α-1, α-smooth muscle actin, MMP 2 and 13, tissue inhibitor of metalloproteinases 1 and 2, tissue growth factor β1, cysteine- and glycine-rich protein 2, and glial fibrillary acidic protein mRNA expression, whereas HCV envelope 2 protein did not exert any significant effect. Blocking of toll-like receptor 2 (TLR2) with a neutralizing antibody prevented mRNA upregulation by HCV core protein confirming that the TLR2 pathway was involved. Furthermore, western blot analysis revealed HCV-induced phosphorylation of the TLR2-dependent signaling molecules ERK1/2, p38 and JNK mitogen-activated kinases. Our in vitro results demonstrate a direct effect of HCV core protein on activation of HSCs toward a profibrogenic state, which is mediated via the TLR2 pathway. Manipulating the TLR2 pathway may thus provide a new approach for antifibrotic therapies in HCV infection.

  17. Baicalin inhibits toll-like receptor 2/4 expression and downstream signaling in rat experimental periodontitis.

    Science.gov (United States)

    Sun, Jun-Yi; Li, Dong-Ling; Dong, Yan; Zhu, Chun-Hui; Liu, Jin; Li, Jue-Dan; Zhou, Tao; Gou, Jian-Zhong; Li, Ang; Zang, Wei-Jin

    2016-07-01

    Periodontitis is a severe inflammatory response, leading to characteristic periodontal soft tissue destruction and alveolar bone resorption. Baicalin possesses potent anti-inflammatory activity; however, it is still unclear whether baicalin regulates toll-like receptor (TLR) 2/4 expression and downstream signaling during the process of periodontitis. In this study, the cervical area of the maxillary second molars of rats was ligated and inoculated with Porphyromonas gingivalis (P. gingivalis) for 4weeks to induce periodontitis. Some rats with periodontitis were treated intragastrically with baicalin (50, 100 or 200mg/kg/day) or vehicle for 4weeks. Compared with the sham group, the levels of TLR2, TLR4 and MyD88 expression and the p38 MAPK and NF-κB activation were up-regulated in the experimental periodontitis group (EPG), accompanied by marked alveolar bone loss and severe inflammation. Treatment with 100 or 200mg/kg/day baicalin dramatically reduced the alveolar bone loss, the levels of HMGB1, TNF-α, IL-1β, and MPO expression, and the numbers of inflammatory infiltrates in the gingival tissues. Importantly, treatment with 100 or 200mg/kg/day baicalin mitigated the periodontitis-up-regulated TLR2, TLR4 and MyD88 expression, and the p38 MAPK and NF-κB activation. Hence, the blockage of the TLR2 and TLR4/MyD88/p38 MAPK/NF-κB signaling by baicalin may contribute to its anti-inflammatory effects in rat model of periodontitis. In conclusion, these novel findings indicate that baicalin inhibits the TLR2 and TLR4 expression and the downstream signaling and mitigates inflammatory responses and the alveolar bone loss in rat experimental periodontitis. Therefore, baicalin may be a potential therapeutic agent for treatment of periodontitis.

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