• Clinical and Experimental Pediatrics
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• v.48 no.3
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• pp.315-320
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• 2005

Objective : Toll like receptor(TLR) is known to be involved in innate immunity. Many microbial antigens stimulate TLR, and as a result of intracellular signal transduction, they activate nuclear factor-kB which produces diverse inflammtory cytokines. Until now, many research topics in Kawasaki disease focused on cytokine increasement. In this study, we aim to reveal TLR increasement which might be associated with initiation of inflammatory response. Methods : We obtained the peripheral blood of ten patients who were diagnosed with Kawasaki disease in Yonsei University College of Medicine from March 2003 to August 2003, as well as those of a febrile control group and the same number of a normal control group. Flow cytometry was done in all samples for quantification of TLR-2 expression in CD14 positive monocyte. And we also extracted total RNA of periphral monocyte and quantificated expression of TLR-2 mRNA by RT-PCR. Results : The expression of TLR-2 in Kawasaki disease increased significantly compared with the normal control group but not when compared with the febrile control group. And the expression decreased slightly in the subacute phase of Kawasaki disease compared with the acute phase, but this was statistically insignificant. mRNA expression of TLR-2 in peripheral blood monocyte also increased in the acute phase of Kawasaki disease. Conclusion : Expression of TLR-2 in Kawasaki disease increased when compared with the normal control group, which means that innate immunity is associated with the pathogenesis of Kawasaki disease.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.33 no.6
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• pp.636-642
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• 2007

Background: CpG DNA plays an important role in immune cell function. This study examined whether the temporal control of toll-like receptor (TLR)9 by CpG DNA can regulate the expression of matrix metalloproteinase-9(MMP-9). Methods and materials: Macrophages were cultured in the presence of 10% FBS. For the various MMP genes analysis, RT-PCR and real-time PCR were performed. In addition, zymography assay performed for the MMP activity. The phosphorylation assay did for the ERK1/2 and NF${\kappa}B$ activation, and luciferase promoter assay was for the NF${\kappa}B$ activity. Results: CpG DNA induced the mRNA expression of MMP-2, MMP-9, and MMP-13, but not of MMP-7, MMP-8, and MMP-12, in a time-dependent manner. Especially, the mRNA expression of MMP-9 was strongly induced by CpG DNA using real-time RT-PCR. The TLR9 inhibitor, chloroquine, suppressed CpG DNA-induced MMP-9 expression and its activity. Moreover, CpG DNA induced the phosphorylation of ERK and the inhibition of ERK by U0126 suppressed CpG DNA-induced MMP-9 expression and its activity. CpG DNA stimulated $I{\kappa}B-{\alpha}$ degradation and luciferase activity. In addition, pretreatment of SN-50, the inhibitor of NF${\kappa}B$, strongly blocked the CpG DNA-induced MMP-9 expression and activity. Conclusion: These observations suggest that CpG DNA may play important roles in the activation of macrophages by regulating the production of MMP-9 via the sequential TLR9-ERK-NF${\kappa}B$ signaling pathway.

• Parasites, Hosts and Diseases
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• v.53 no.4
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• pp.431-438
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• 2015

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

• Molecular & Cellular Toxicology
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• v.5 no.2
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• pp.141-146
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• 2009

Toll-like receptors (TLRs) induce innate immune responses by recognizing conserved microbial structural molecules. All TLR signaling pathways culminate in the activation of nuclear factor kappa-B (NF-$\kappa$B) leading to the induction of inflammatory gene products such as cyclooxygenase-2 (COX-2). Deregulated activation of TLRs can lead to the development of severe systemic inflammation. Divalent heavy metals, cadmium and mercury, have been used for thousands of years. While cadmium and mercury are clearly toxic to most mammalian organ systems, especially the immune system, their underlying toxic mechanism(s) remain unclear. Here, we report biochemical evidence that cadmium, but not mercury, inhibits NF-$\kappa$B activation and COX-2 expression induced by TLR2 or TLR4 agonists, while cadmium does not inhibit NF-$\kappa$B activation induced by the downstream signaling component of TLRs, MyD88. Thus, the target of cadmium to inhibit NF-$\kappa$B activation may be upstream of MyD88 including TLRs themselves, or events leading to TLR activation by agonists.

• Food Science and Biotechnology
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• v.17 no.6
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• pp.1294-1298
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• 2008

Toll-like receptors (TLRs) induce innate immune responses recognizing conserved microbial structural molecules. All TLR signaling pathways culminate in the activation of nuclear factor-${\kappa}B$ (NF-${\kappa}B$). The activation of NF-${\kappa}B$ leads to the induction of inflammatory gene products such as cyclooxygenase-2 (COX-2). Guggul has been used for centuries to treat a variety of diseases. Guggulstreone, one of the active ingredients in guggul, has been used to treat many chronic diseases. However, the mechanism as to how guggulsterone mediate the health effects is largely unknown. Here, we report biochemical evidence that guggulsterone inhibits the NF-${\kappa}B$ activation and COX-2 expression induced by TLR2, TLR3, and TLR4 agonists. Guggulsterone also inhibits the NF-${\kappa}B$ activation induced by downstream signaling components of TLRs, myeloid differential factor 88 (MyD88), $I{\kappa}B$ kinase ${\beta}$ ($IKK{\beta}$), and p65. These results imply that guggulsterone can modulate the immune responses regulated by TLR signaling pathways.

• The Korean Journal of Physiology and Pharmacology
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• v.19 no.5
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• pp.461-465
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• 2015

Microglia, the resident macrophages in the central nervous system, can rapidly respond to pathological insults. Toll-like receptor 2 (TLR2) is a pattern recognition receptor that plays a fundamental role in pathogen recognition and activation of innate immunity. Although many previous studies have suggested that TLR2 contributes to microglial activation and subsequent pathogenesis following brain tissue injury, it is still unclear whether TLR2 has a role in microglia dynamics in the resting state or in immediate-early reaction to the injury in vivo. By using in vivo two-photon microscopy imaging and $Cx3cr1^{GFP/+}$ mouse line, we first monitored the motility of microglial processes (i.e. the rate of extension and retraction) in the somatosensory cortex of living TLR2-KO and WT mice; Microglial processes in TLR2-KO mice show the similar motility to that of WT mice. We further found that microglia rapidly extend their processes to the site of local tissue injury induced by a two-photon laser ablation and that such microglial response to the brain injury was similar between WT and TLR2-KO mice. These results indicate that there are no differences in the behavior of microglial processes between TLR2-KO mice and WT mice when microglia is in the resting state or encounters local injury. Thus, TLR2 might not be essential for immediate-early microglial response to brain tissue injury in vivo.

• Asian-Australasian Journal of Animal Sciences
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• v.28 no.2
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• pp.273-279
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• 2015

Leptospiral lipopolysaccharide (L-LPS) has shown potency in activating toll-like receptor 2 (TLR2) in pig fibroblasts (PEFs_NCC1), and causes the expression of proinflammatory cytokines. However, the stimulation by L-LPS was weak eliciting the function of TLR2 sufficiently in pig innate immunity responses during Leptospira infection. In this study, the immune response of pig embryonic fibroblast cell line (PEFs_SV40) was investigated and was found to be the high immune response, thus TLR2 is the predominate receptor of L-LPS in pig cells. Further, we found a strategy using the antibody against L-LPS, to prevent L-LPS interaction with TLR2 in pig cells which could impact on immune activation.

• Anatomy and Cell Biology
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• v.56 no.2
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• pp.228-235
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• 2023

Toll-like receptors (TLRs) are the mammalian ortholog of Drosophila melanogaster protein Toll, originally identified for its involvement in embryonic development. In mammals, TLRs are mainly known for their ability to recognize pathogen- or damage-associated molecular patterns and, consequently, to initiate the immune response. However, it is becoming clear that TLRs can play a role also in mammal embryo development. We have previously described TLR4 and TLR7 expression in developing mouse peripheral nervous system and gastrointestinal tract. In the present study, we extended the investigation of TLR4 and TLR7 to the respiratory system and to the two main accessory organs of the digestive system, the liver and pancreas. TLR4 and TLR7 immunostaining was performed on mouse conceptuses collected at different stages, from E12 to E18. TLR4 and TLR7 immunoreactivity was evident in the embryo pancreas and liver at E12, while, in the respiratory apparatus, appeared at E14 and E17, respectively. Although further studies are required to elucidate the specific role of these TLRs in embryo development, the differential spatiotemporal TLR4 and TLR7 appearance may suggest that TLR expression in developing embryos is highly regulated for a possible their direct involvement in the formation of the organs and in the acquisition of immune-related features in preparation for the birth.

• Journal of Microbiology and Biotechnology
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• v.17 no.11
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• pp.1862-1867
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• 2007

An individual's immune response is critical for host protection from many different pathogens, and the responsiveness can be assessed by the amount of cytokine production upon stimulating bacterial components such as lipopolysaccharide (LPS). The difference between individuals in their peripheral blood mononuclear cells (PBMC) responsiveness to LPS, a Gram-negative endotoxin, was investigated from 27 healthy individuals. We observed a large variation in $IFN{\gamma}$ production among different individuals. The PBMC of the consistently three highest and three lowest $IFN{\gamma}$ producers were investigated. Since previous studies described that a single point mutation in the coding region of TLR2 and TLR4 is linked to the individual responsiveness to pathogenic bacterial infections, we first examined the known point mutations in the coding region of $TLR2^{Pro681His}$, $TLR4^{Pro714His}$ located in the cytoplasmic regions of the Toll-like domain as well as $TLR4^{Asp299Gly}$ located in the extracellular region. None of these mutations were associated with an individual's responsiveness to LPS, despite the presence of $TLR4^{Asp299Gly}$ mutation. Further investigation revealed that the variation of PBMC responsiveness to LPS among healthy individuals was due to constitutive expression levels of TLR4 and TLR2. This result is consistent with an aging-related low expression of Toll-like receptors in the mouse model of LPS responsiveness. The present study therefore suggests that the constitutive expression levels of TLR2 and TLR4 may contribute to the individual response to LPS.

• BMB Reports
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• v.49 no.6
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• pp.305-310
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• 2016

Toll-like receptors (TLRs) play a critical role in the innate immune response against pathogens. Each TLR recognizes specific pathogen-associated molecular patterns, after which they activate the adaptor protein MyD88 or TRIF-assembled signaling complex to produce immune mediators, including inflammatory cytokines and type I IFNs. Although the activation of TLR is important for host defense, its uncontrolled activation can damage the host. During the past decade, numerous studies have demonstrated that GSK3β is a key regulator of inflammatory cytokine production in MyD88-mediated TLR signaling via TLR2 and TLR4. Recently, GSK3β has also been implicated in the TRIF-dependent signaling pathway via TLR3. In this review, we describe current advances on the regulatory role of GSK3β in immune responses associated with various TLRs. A better understanding of the role of GSK3β in TLR signaling might lead to more effective anti-inflammatory interventions.