OBJECTIVE: The aim of this study was to clarify whether stimulation of recombinant IL-17, TLR2 and TLR4 by their specific ligands induces the production of RANKL and IL-6 in the fibroblast-like synoviocytes (FLSs) from RA patients. METHODS: FLSs were isolated from RA synovial tissues and they were stimulated with the IL-17, TLR2 ligand bacterial peptidoglycan (PGN) and TLR4 ligand lipopolysaccharide (LPS). The RANKL levels were assessed by RT-PCR and western blotting. The expressions of IL-17, TLR2, TLR4, RANKL and IL-6 in the RA synovium were quantified by immunohistochemistry and these values were compared with the values obtained in the osteoarthritis synovium. The increased IL-6 production in the culture supernatants of the RA FLSs was quantified by sandwich ELISA. RESULTS: The mRNA and protein levels of RANKL and IL-6 increased in the RA FLSs stimulated with PGN, LPS and IL-17, or PGN plus IL-17 or LPS plus IL-17. The expressions of IL-17, TLR2, TLR4, RANKL and IL-6 were much higher in the RA synovium than those in the osteoarthritis (OA) synovium. CONCLUSION: We observed synergistic effects of TLR-2, TLR-4 and IL-17 upon the induction of RANKL. In conclusion, our data supports the previous evidence of an important role of TLR-2, TLR-4 and IL-17 in the pathogenesis of RA.
Blotting, Western ; Fibroblasts ; Humans ; Immunohistochemistry ; Interleukin-17 ; Interleukin-6 ; Ligands ; Osteoarthritis ; Peptidoglycan ; RNA, Messenger ; Synovial Membrane ; Toll-Like Receptor 2 ; Toll-Like Receptor 4 ; Toll-Like Receptors

We investigated the question of whether 7-oxygenated cholesterol derivatives could affect inflammatory and/or immune responses in atherosclerosis by examining their effects on expression of IL-23 in monocytic cells. 7alpha-Hydroxycholesterol (7alphaOHChol) induced transcription of the TLR6 gene and elevated the level of cell surface TLR6 protein in THP-1 monocytic cells. Addition of an agonist of TLR6, FSL-1, to TLR6-expressing cells by treatment with 7alphaOHChol resulted in enhanced production of IL-23 and transcription of genes encoding the IL-23 subunit alpha (p19) and the IL-12 subunit beta (p40). However, treatment with 7-ketocholesterol (7K) and 7beta-hydroxycholesterol (7betaOHChol) did not affect TLR6 expression, and addition of FSL-1 to cells treated with either 7K or 7betaOHChol did not influence transcription of the genes. Pharmacological inhibition of ERK, Akt, or PI3K resulted in attenuated transcription of TLR6 induced by 7alphaOHChol as well as secretion of IL-23 enhanced by 7alphaOHChol plus FSL-1. Inhibition of p38 MAPK or JNK resulted in attenuated secretion of IL-23. These results indicate that a certain type of 7-oxygenated cholesterol like 7alphaOHChol can elicit TLR6-mediated expression of IL-23 by monocytic cells via PI3K/Akt and MAPKs pathways.
Atherosclerosis ; Cholesterol ; Interleukin-12 ; Interleukin-23* ; Macrophages ; p38 Mitogen-Activated Protein Kinases ; Toll-Like Receptor 6

OBJECTIVETo explore the role of toll-like receptor 2 (TLR2) and toll-like receptor 4 (TLR4) in myocardial ischemia/reperfusion injury (MI/RI) by observing the dynamic expression changes at mRNA and protein levels early after myocardial ischemia/reperfusion (I/ R).

METHODSThe Wistar rats were randomly divided into Sham and I/R group (n = 42), and killed according to different reperfusion time (1, 2, 4, 6, 12, 24 h and 7 d). Structural and morphous changes of myocytes were observed under optical microscope. The mRNA and protein levels of TLR2 and TLR4 were detected using real-time PCR (RT-PCR). Monocyte chemokine protein-1 (MCP-1) and interleukine-6 (IL-6) mRNA levels were measured by reverse transcriptase-polymerase chain reaction (rt-PCR).

RESULTS(1) With the extension of reperfusion time, the myocardial infarct size increased smoothly, and reached the plateau at 4 h, then stayed in the platform. After reperfusion for 7 d, the ventricular had been remodeled. (2) At the beginning of reperfusion, myocardial structure showed no significant change in Sham group, but had different degrees of injury in I/R group. In rats of the group reperfused for 7 d the left ventricular remodeling could be visible. (3) Compared to sham group,TIR2, TLR4, MCP-1, IL-6 mRNA level were increased in myocardium in I/R group. TLR2 and TLR4 both peaked at 4 h of reperfusion, IL6 peaked at 6 h, followed by a gradually decrease. TLR4 and IL-6 mRNA levels rose again at 7 d. MCP-1 level in I/R group remained fairly with sham group at the beginning of reperfusion, and markedly elevated at 7 d.

CONCLUSIONExpression of TLRs mRNA in myocardium during early after myocardial ischemia/reperfusion increased rapidly and activated TLRs might play an important role in MI/RI through promoting the generation of inflammatory factors. At the late reperfusion, TLRs levels raise again and the expression of inflammatory factors increase once again, Those may probably affect the remodeling of ventricular, and injure myocardial structure and function.

Animals ; Chemokine CCL2 ; metabolism ; Disease Models, Animal ; Interleukin-6 ; metabolism ; Male ; Myocardial Reperfusion Injury ; metabolism ; Rats ; Rats, Wistar ; Toll-Like Receptor 2 ; metabolism ; Toll-Like Receptor 4 ; metabolism

OBJECTIVE: Rheumatoid arthritis (RA) is a chronic autoimmune disease. Macrophage migration inhibitory factor (MIF) has been shown to be an important pro-inflammatory cytokine in RA. The aim of this study was to determine if the engagement of toll-like receptor 3 (TLR3) induces the production of MIF in the fibroblast-like synoviocytes (FLS) of patients with RA. METHODS: The expression of inflammatory cytokines (e.g. MIF, IL-6, IL-1beta and TNFalpha) and toll-like receptors (e.g. TLR2, TLR3 and TLR4) in the synovial tissue were quantified by immunohistochemistry. FLS were isolated from the synovial tissues of patients with RA and stimulated with TLR-3 ligand polyI:C, in the presence of a neutralizing antibody against IL-6. The concentrations of MIF and IL-6 in the culture supernatants from the FLS were measured using sandwich ELISA. RESULTS: The engagement of TLR3 with PolyI:C increased the production of MIF in FLS. The stimulatory effect of these TLR ligands showed a dose-dependent trend. The combination of TLR3 and TLR4 synergistically increased the level of MIF and IL-6 production. The addition of neutralizing antibodies against IL-6 abrogated the stimulatory effect of the ligands of TLR3 and TLR4 on the production of MIF. CONCLUSION: These results show that TLR3 engagement stimulates the production of MIF and IL-6. Therefore, the TLRs help perpetuate of RA pathogenesis through production of MIF from the FLS in patients with RA, and might provide a new therapeutic approach for the treatment of rheumatoid arthritis.
Antibodies, Neutralizing ; Arthritis, Rheumatoid ; Autoimmune Diseases ; Cytokines ; Enzyme-Linked Immunosorbent Assay ; Humans ; Immunohistochemistry ; Interleukin-6 ; Ligands ; Macrophages ; Toll-Like Receptor 3 ; Toll-Like Receptors ; Up-Regulation

PURPOSE: Toll-like receptor 2 (TLR2) is critical in the immune response to mycobacterial infections. The purpose of this study was to analyze TLR2 surface expressions and TLR2-mediated tumor necrosis factor-alpha (TNF-alpha) and interleukin-6 (IL-6) production in patients with BCG vaccine-associated suppurative lymphadenitis. METHODS: Peripheral monocytes were separated from 16 patients with BCG vaccine-associated suppurative lymphadenitis and 10 healthy controls using a magnet cell isolation kit. Monocytes (1x10(6) cells/well) were incubated with a constant amount of Pam(3)CSK(4) (100 microgram/mL) for 24 hours. TLR2 surface expression on monocytes was analyzed by FACS analysis and TLR-2 mRNA expression was determined by RT-PCR. TLR2-mediated TNF-alpha and IL-6 production were measured by ELISA. RESULTS: In patients with BCG vaccine-associated suppurative lymphadenitis, low TLR2 expression on monocytes (3.39+/-1.2% versus 4.64+/-2.6%) together with significantly lower TLR2 mRNA expression than in the healthy controls was seen after Pam(3)CSK(4) stimulation. TLR2-mediated TNF-alpha and IL-6 production in patients with BCG vaccine-associated suppurative lymphadenitis (TNF-alpha, 775.5+/-60.8 pg/mL; IL-6, 4,645.8+/-583.9 pg/mL) were also lesser than that in healthy controls (TNF-alpha, 1,098.5+/-94.3 pg/mL; IL-6, 6,696.3+/-544.3 pg/mL). CONCLUSION: These findings suggest that low TLR2 expression on monocytes might be associated with increased susceptibility to BCG vaccine-associated suppurative lymphadenitis.
Cell Separation ; Enzyme-Linked Immunosorbent Assay ; Humans ; Interleukin-6 ; Lymphadenitis ; Magnets ; Monocytes ; Mycobacterium bovis ; RNA, Messenger ; Toll-Like Receptor 2 ; Toll-Like Receptors ; Tumor Necrosis Factor-alpha

Sequestosome 1 (SQSTM1, p62), a ubiquitin binding protein, plays a role in cell signaling, oxidative stress, and autophagy. However, its functional role in inflammatory signaling is controversial. Recent studies have shown that p62 is negatively implicated in inflammatory responses. But, the precise molecular mechanisms by which p62 regulates inflammatory responses remain unclear. In this study, we report on a new regulatory role for p62 in TLR4-mediated signaling. p62 overexpression led to the suppression of NF-κB activation and the production of pro-inflammatory cytokines, TNF-α, IL-6, and IL-1β in response to TLR4 stimulation. In contrast, p62(−/−) mouse embryonic fibroblast (MEF) cells exhibited marked enhancement of NF-κB activation and production of pro-inflammatory cytokines by TLR4 stimulation, compared to p62(+/+) MEF cells. Additionally, the TLR4-induced activation of signal transduction was significantly augmented in p62(−/−) MEF cells, indicating that p62 was negatively implicated in TLR4-mediated signaling. Biochemical studies revealed that p62 interacted with the internal domain of evolutionarily conserved signaling intermediate in Toll pathways (ECSIT), which is critical for associating with the TNF receptor associated factor 6 (TRAF6)-ECSIT complex to activate NF-κB in TLR4 signaling. Interestingly, p62-ECSIT interaction inhibited the interaction between TRAF6 and ECSIT and attenuated the ubiquitination of ECSIT. Furthermore, upon LPS challenge, the mortality of p62(−/−) (p62-knockout) mice was markedly enhanced compared to p62(+/+) (p62 wild-type) mice. Taken together, our data demonstrate that p62 negatively regulated TLR4 signaling via functional regulation of the TRAF6-ECSIT complex.
Animals ; Autophagy ; Carrier Proteins ; Cytokines ; Fibroblasts ; Interleukin-6 ; Mice ; Mortality ; Oxidative Stress ; Signal Transduction ; TNF Receptor-Associated Factor 6 ; Toll-Like Receptor 4 ; Ubiquitin ; Ubiquitination

6-kDa early secretory antigenic target (ESAT6), a virulent factor of Mycobacterium tuberculosis, is involved in immune regulation. However, the underlying mechanism behind the activation and maturation of dendritic cells (DCs) by ESAT6 remains unclear. In this study, we investigated the effect on TLRs signaling on the regulation of ESAT6-induced activation and maturation of DCs. ESAT6 induced production of IL-6, TNF-α, and IL-12p40 in bone marrow-derived dendritic cells (BMDCs) from wild-type and TLR2-deficient mice, with this induction abolished in TLR4-deficient cells. NF-κB is essential for the ESAT6-induced production of the cytokines in BMDCs. TLR4 was also required for ESAT6-induced activation of NF-κB and MAPKs in BMDCs. ESAT6 additionally upregulated the expression of surface molecules CD80, CD86, and MHC-II, and also promoted the ability of CD4⁺ T cells to secrete IFN-γ via the TLR4-dependent pathway. Our findings suggest that TLR4 is critical in the activation and maturation of DCs in response to ESAT6.
Animals ; Cytokines ; Dendritic Cells ; Interleukin-12 Subunit p40 ; Interleukin-6 ; Mice ; Mycobacterium tuberculosis ; Mycobacterium ; T-Lymphocytes ; Toll-Like Receptor 4

OBJECTIVETo investigate the protective mechanism of endoplasmic reticulum stress (ERS) inhibition against inflammation-induced acute liver injury using a mouse model.

METHODSMarrow-derived stem cells were isolated from mouse femur and used to derive macrophages for analysis in experimental inflammation conditions, established by exposure to LPS and consequent activation of TLR4. Tunicamycin, an ERS chemical inducer, was applied to interfere the inflammation model condition.Affect on the inflammation-related factor MAPK was detected by western blot, and affects on gene expression of inflammatory factors were measured by real-time quantitative PCR. Affect on TNFa was also measured by ELISA.

RESULTSExpression of TNFa, IL-6 and IL-1b was induced upon exposure to LPS, with the peak levels being reached at 4 hours of exposure (TNFa, 0.82+/-0.24; IL-1 b, 2.20+/-0.69; IL-6, 0.330+/-0.150). Tunicamycin significantly enhanced the LPS-induced up-regulation of TNFa, IL-6 and IL-1b expression (TNFa, 1.44+/-0.38, t=2.8, P<0.05; IL-1b, 16.063.40, t =7.93, P<0.05; IL-6, 31.1610.60, t=5.08, P<0.05). The tuniamycin treatment also enhanced the LPS-induced up-regulation of the protein expression of phospo-p38, phospho-JNK and phoshpo-ERK.

CONCLUSIONERS collaborates with LPS to promote the TLR4-mediated inflammatory response of macrophages, and this collaboration may be a pathogenic mechanism underlying progressive development of acute liver injury.

Animals ; Disease Models, Animal ; Endoplasmic Reticulum Stress ; Inflammation ; Interleukin-6 ; Lipopolysaccharides ; Liver ; Macrophages ; Mice ; Toll-Like Receptor 4 ; Up-Regulation

The innate immune response in patients who develop inflammatory bowel disease (IBD) may be abnormal. However, the exact role of Toll-like receptors (TLRs) / CD14 gene in the pathogenesis of IBD has not been fully elucidated. We aimed to investigate the association between polymorphisms of TLR1, 2, 4, 6, and CD14 gene and susceptibility to IBD in Korean population. A total 144 patients of IBD (99 patients with ulcerative colitis, 45 patients with Crohn's disease) and 178 healthy controls were enrolled. Using a PCR-RFLP, we evaluated mutations of TLR1 (Arg80Thr), TLR2 (Arg753Gln and Arg677Trp), TLR4 (Asp299Gly and Thr399Ile), TLR6 (Ser249Pro) genes and the -159 C/T promoter polymorphism of CD14 gene. No TLR polymorphisms were detected in Korean subjects. T allele and TT genotype frequencies of CD14 gene were significantly higher in IBD patients than in healthy controls. In subgroup analysis, T allelic frequency was higher in pancolitis phenotype of ulcerative colitis. In Korean population, the promoter polymorphism at -159 C/T of the CD14 gene is positively associated with IBD, both ulcerative colitis and Crohn's disease.
Adult ; Aged ; Alleles ; Antigens, CD14/*genetics ; Asian Continental Ancestry Group/*genetics ; Colitis, Ulcerative/genetics ; Crohn Disease/genetics ; Female ; Gene Frequency ; Genetic Predisposition to Disease ; Genotype ; Humans ; Inflammatory Bowel Diseases/*genetics ; Male ; Middle Aged ; Phenotype ; Polymorphism, Single Nucleotide ; Promoter Regions, Genetic ; Republic of Korea ; Toll-Like Receptor 1/genetics ; Toll-Like Receptor 2/genetics ; Toll-Like Receptor 4/genetics ; Toll-Like Receptor 6/genetics ; Toll-Like Receptors/*genetics

TLR2 activity plays an important role in the pathogenesis of autoimmune diseases, tumor carcinogenesis and cardio-cerebrovascular diseases. To establish a TLR2 receptor-based cell screening model, NF-kappaB promoter-driven luciferase reporter plasmids were transfected into human embryonic kidney cells (HEK293) stably expressing human TLR2 and co-receptors CD14, TLR1 and TLR6. Single clones were then isolated and characterized. Using this screening system, a human TLR2-binding peptide C8 was obtained from the Ph.D.-7 Phage Display Peptide Library through biopanning and rapid analysis of selective interactive ligands (BRASIL). The binding characteristic of C8 with human TLR2 was evaluated by ELISA, flow cytometry and immunofluorescence. The NF-kappaB luciferase activity assay showed that C8 could activate the TLR2/TLR1 signaling pathway and induce the production of cytokines TNF-alpha and IL-6. In conclusion, the TLR2 receptor-based cell screening system is successfully established and a new TLR2-binding peptide is identified by using this system.
Bacteriophages ; Drug Evaluation, Preclinical ; Genes, Reporter ; HEK293 Cells ; Humans ; Interleukin-6 ; metabolism ; Lipopolysaccharide Receptors ; metabolism ; Luciferases ; genetics ; metabolism ; Peptide Library ; Peptides ; metabolism ; pharmacology ; Promoter Regions, Genetic ; Protein Binding ; Signal Transduction ; drug effects ; Toll-Like Receptor 1 ; metabolism ; Toll-Like Receptor 2 ; metabolism ; Toll-Like Receptor 6 ; metabolism ; Transfection ; Tumor Necrosis Factor-alpha ; metabolism