Dendritic cells (DCs) comprise two functionally distinct subsets: plasmacytoid DCs (pDCs) and myeloid DCs (mDCs). pDCs are specialized in rapid and massive secretion of type I interferon (IFN-I) in response to nucleic acids through Toll like receptor (TLR)-7 or TLR-9. In this report, we characterized a CD56(+) DC population that express typical pDC markers including CD123 and BDCA2 but produce much less IFN-I comparing with pDCs. In addition, CD56(+) DCs cluster together with mDCs but not pDCs by genome-wide transcriptional profiling. Accordingly, CD56(+) DCs functionally resemble mDCs by producing IL-12 upon TLR4 stimulation and priming naïve T cells without prior activation. These data suggest that the CD56(+) DCs represent a novel mDC subset mixed with some pDC features. A CD4(+)CD56(+) hematological malignancy was classified as blastic plasmacytoid dendritic cell neoplasm (BPDCN) due to its expression of characteristic molecules of pDCs. However, we demonstrated that BPDCN is closer to CD56(+) DCs than pDCs by global gene-expression profiling. Thus, we propose that the CD4(+)CD56(+) neoplasm may be a tumor counterpart of CD56(+) mDCs but not pDCs.
Biomarkers ; metabolism ; CD56 Antigen ; genetics ; immunology ; Cell Lineage ; genetics ; immunology ; Dendritic Cells ; immunology ; metabolism ; pathology ; Gene Expression ; Hematologic Neoplasms ; genetics ; immunology ; pathology ; Humans ; Immunophenotyping ; Interferon Type I ; biosynthesis ; metabolism ; Interleukin-12 ; biosynthesis ; metabolism ; Interleukin-3 Receptor alpha Subunit ; genetics ; immunology ; Lectins, C-Type ; genetics ; immunology ; Membrane Glycoproteins ; genetics ; immunology ; Myeloid Cells ; immunology ; metabolism ; pathology ; Receptors, Immunologic ; genetics ; immunology ; Terminology as Topic ; Toll-Like Receptor 4 ; genetics ; immunology ; Toll-Like Receptor 7 ; genetics ; immunology ; Toll-Like Receptor 9 ; genetics ; immunology

Toll-like receptors (TLRs) family may play important roles in inflammatory bowel disease. This study examined the expression of TLR2, TLR4 and TLR9 in the colonic tissues of patients with ulcerative colitis (UC) and explored their roles in the pathogenesis of UC. Colonic biopsies were taken from the colon of 30 patients with mild or moderate UC (at active phase) and 10 healthy controls during colonoscopy. TLR2, TLR4 and TLR9 protein expression levels were immunohistochemically detected. The mRNA expression levels of TLR2, TLR4 and TLR9 were assessed by reverse transcription polymerase chain reaction (RT-PCR). The disease activity index (DAI), colonoscopic and histologic grades and fecal microbial flora were determined. Histological examination showed that the intestinal mucous membrane of UC patients underwent acute inflammation changes. Immunohistochemistry exhibited that the expression levels of TLR2, TLR4 and TLR9 in colon epithelia and inflammatory cells were higher in UC patients than in control group (P<0.01). The mRNA expression levels of TLR2, TLR4 and TLR9 were increased in UC patients but were not detected in the normal controls. Expression levels of TLR2, TLR4 and TLR9 were positively correlated, and bore close correlation with DAI, colonoscopic and histologic grades and fecal microbial flora. An important mechanism of UC might be that abnormal activation of mucosal immunity by intestinal dysbacteriosis caused dysregulation of TLRS that mediates innate immunity.
Colitis, Ulcerative ; genetics ; metabolism ; pathology ; Colon ; metabolism ; microbiology ; Colonoscopy ; Feces ; microbiology ; Female ; Gene Expression ; Humans ; Immunohistochemistry ; Intestinal Mucosa ; metabolism ; microbiology ; Male ; Reverse Transcriptase Polymerase Chain Reaction ; Severity of Illness Index ; Toll-Like Receptor 2 ; biosynthesis ; genetics ; Toll-Like Receptor 4 ; biosynthesis ; genetics ; Toll-Like Receptor 9 ; biosynthesis ; genetics

In order to investigate the role of Toll-like receptor 4 (TLR4) in cerebrocardiac syndrome (CCS), the partial cerebral ischemia/reperfusion (I/R) models in mice with different TLR4 genotypes were established in the present study. TLR4 wild-type (C3H/HeN) and mutant (C3H/HeJ) mice of 6-8 weeks of age were divided into 4 groups at random: C3H/HeN sham group (n=10), C3H/HeJ sham group (n=10), C3H/HeN model group (n=10) and C3H/HeJ model group (n=10). Partial cerebral I/R was caused by the middle cerebral artery occlusion (MCAO) to duplicate CCS models in mice. After the operation, the electrocardiogram (ECG), the level of tumor necrosis factor-alpha (TNF-α) in myocardial tissue and the cardiac pathological changes were observed in each group. It was shown that the brain infarct volume in C3H/HeN model group was larger than that in C3H/HeJ model group (P<0.01). The ST segment change and T wave inversion occurred frequently in model groups. Moreover, the TNF-α level in C3H/HeN model group was higher than that in C3H/HeJ model group (P<0.01). The myocardial injury was aggravated in C3H/HeN group as compared with C3H/HeJ group. It was concluded that TLR4 was implicated in the development of CCS.
Animals ; Brain Ischemia ; genetics ; Electrocardiography ; Humans ; Mice ; Myocardial Reperfusion Injury ; genetics ; Myocardium ; metabolism ; pathology ; Signal Transduction ; Toll-Like Receptor 4 ; biosynthesis ; deficiency ; genetics ; Tumor Necrosis Factor-alpha ; genetics

We evaluated the effectiveness of rhamnogalacturonan II (RG-II)-stimulated bone marrow-derived dendritic cells (BMDCs) vaccination on the induction of antitumor immunity in a mouse lymphoma model using EG7-lymphoma cells expressing ovalbumin (OVA). BMDCs treated with RG-II had an activated phenotype. RG-II induced interleukin (IL)-12, IL-1beta, tumor necrosis factor-alpha (TNF-alpha) and interferon-gamma (IFN-gamma) production during dendritic cell (DC) maturation. BMDCs stimulated with RG-II facilitate the proliferation of CD8+ T cells. Using BMDCs from the mice deficient in Toll-like receptors (TLRs), we revealed that RG-II activity is dependent on TLR4. RG-II showed a preventive effect of immunization with OVA-pulsed BMDCs against EG7 lymphoma. These results suggested that RG-II expedites the DC-based immune response through the TLR4 signaling pathway.
Acute-Phase Proteins/metabolism ; Adaptor Proteins, Vesicular Transport/metabolism ; Animals ; Antigens, CD14/metabolism ; Bone Marrow Cells/cytology/drug effects ; CD8-Positive T-Lymphocytes/*immunology ; Carrier Proteins/metabolism ; Cell Differentiation/drug effects ; Cell Nucleus/drug effects/metabolism ; Cell Proliferation/drug effects ; Cytokines/biosynthesis ; Dendritic Cells/cytology/drug effects/enzymology/*immunology ; Enzyme Activation/drug effects ; Lymphocyte Activation/*drug effects ; Membrane Glycoproteins/metabolism ; Mice ; Mice, Inbred C57BL ; Mice, Knockout ; Mitogen-Activated Protein Kinases/metabolism ; Myeloid Differentiation Factor 88/metabolism ; NF-kappa B/metabolism ; Neoplasms/immunology/*pathology ; Pectins/*pharmacology ; Phenotype ; Protein Transport/drug effects ; Receptors, Chemokine/metabolism ; Signal Transduction/drug effects ; T-Lymphocytes, Cytotoxic/cytology/drug effects ; Toll-Like Receptor 4/*agonists/metabolism

Myeloid-related protein (MRP)8/MRP14 is an endogenous Toll-like receptor 4 (TLR4) ligand and is abundant in synovial fluid (SF) of rheumatoid arthritis (RA) patients. Belonging to damage-associated molecular patterns, it amplifies proinflammatory mediators and facilitates a wide range of inflammatory and autoimmune diseases. Interleukin (IL)-17-producing T-helper (Th)17 cells have a crucial role in RA pathogenesis, and IL-6 is the key factor promoting Th17 differentiation. We investigated whether the level of MRP8/MRP14 is positively associated with IL-6 and IL-17 levels in RA SF and found that MRP8/MRP14 level had a significant correlation with IL-6 and IL-17 levels in RA SF. We also observed that MRP8-induced IL-17 production by peripheral blood mononuclear cells but MRP14 did not. Upon stimulation with MRP8, IL-6 production was enhanced by RA fibroblast-like synoviocytes (FLS) and was further elevated by coculturing RA FLS with activated CD4+ T cells. Moreover, we demonstrated that MRP8-activated IL-6 production by RA FLS promoted differentiation of Th17 cells using the coculture system consisting of CD4+ T cells and RA FLS. In addition, IL-6 blockade attenuated Th17 polarization of CD4+ T cells in the cocultures. Inhibitor studies revealed that MRP8 increased IL-6 production in RA FLS via TLR4/phosphoinositide 3-kinase/nuclear factor-kappaB and mitogen-activated protein kinase signaling pathways. Our results show that MRP8 has a crucial role in stimulating IL-6 expression by RA FLS, and subsequently promotes Th17 differentiation in RA, suggesting that neutralizing MRP8 level in RA synovium may be an effective therapeutic strategy in RA treatment.
ATP-Binding Cassette Transporters/*metabolism ; Adult ; Aged ; Arthritis, Rheumatoid/*pathology ; CD4-Positive T-Lymphocytes/metabolism ; Calgranulin B/metabolism ; Cell Differentiation/*immunology ; Fibroblasts/*metabolism/pathology ; Humans ; Inflammation Mediators/metabolism ; Interleukin-17/metabolism ; Interleukin-6/*biosynthesis ; Middle Aged ; Signal Transduction/immunology ; Synovial Fluid/cytology ; Synovial Membrane/metabolism/pathology ; Th17 Cells/*pathology ; Toll-Like Receptor 4/metabolism ; *Up-Regulation

Toll-like receptors (TLRs) are key components of the innate immune system which trigger antimicrobial host defense responses. This study aimed to investigate the impact of probiotics (Lactobacillus, Bifidobacterium) on the expression of TLR4 and tumor necrosis factor-alpha (TNF-α) in the colon mucosa of rat experimental ulcerative colitis model induced by trinitrobenzene sulfonic acid (TNBS)/ethanol and immune complexes. The gross and histological changes of the colonic mucosa were observed and assessed by the means-standard deviation and independent samples t-test. The protein expression levels of TLR4 and TNF-α were detected by using immunohistochemistry and Western blotting, respectively. It was revealed that there was visible infiltration of inflammatory cells, formation of crypt abscess, and the reduction of goblet cells in the colon tissue of experimental models. As compared with the control group, the levels of TLR4 and TNF-α protein were significantly increased in the model group (P<0.01 for both). No significant difference was found in the expression of TLR4 and TNF-α between the two-week probiotics treatment group and the model group (P>0.05), whereas significant reductions were shown in rats which were treated with probiotics for four weeks as compared with the model group (P<0.01). There was no significant difference between two probiotics-treated groups. Our results implied that probiotics were likely to play a key role in protecting ulcerative colitis by reducing the inflammatory factor TNF-α expression through inhibiting the TLR4 expression in the colon tissue of experimental models.
Animals ; Bifidobacterium ; physiology ; Blotting, Western ; Colitis, Ulcerative ; chemically induced ; metabolism ; Colon ; drug effects ; metabolism ; microbiology ; Immunohistochemistry ; Intestinal Mucosa ; drug effects ; metabolism ; microbiology ; Lactobacillus ; physiology ; Male ; Probiotics ; pharmacology ; Rabbits ; Rats ; Rats, Sprague-Dawley ; Time Factors ; Toll-Like Receptor 4 ; biosynthesis ; Trinitrobenzenesulfonic Acid ; Tumor Necrosis Factor-alpha ; metabolism

BACKGROUNDCornea epithelial cells play early and crucial roles in the initiation of ocular surface responses to pathogens. Participation of toll-like receptor (TLR) 2 and TLR4, which are major forms of fungi receptors, may be involved in Aspergillus fumigatus induced immune responses. The objective of the present study was to examine whether inactive Aspergillus fumigatus conidia induce NF-kappaB activation and production of proinflammatory cytokines, and whether the expression of TLR2 and TLR4 were amplified by conidia in cultured immortalized human corneal epithelial cells (THCEs). This may contribute to our knowledge of the mechanism by which the host cornea can successfully defend against invasive fungi.

METHODSAspergillus fumigatus conidia were used to challenge THCE cells. THCE cells were harvested after 0.5, 1, 2 or 4 hours incubation. Real-time quantitative PCR was performed to determine the expression of TLR2, TLR4, TNF-alpha and IL-8. Western blotting was performed to determine the expression of NF-kappaB. Enzyme-linked immunosorbent assay (ELISA) was performed to determine the expression of TNF-alpha and IL-8. And the release of TNF-alpha and IL-8 in the cell supernatant were also assessed by ELISA with or without pretreatment with TLR2 and TLR4 neutralizing antibodies.

RESULTSAspergillus fumigatus conidia elicited the expression of TLR2, TLR4, TNF-alpha and IL-8 mRNA in THCEs. Exposure of THCE cells to Aspergillus fumigatus conidia resulted in NF-kappaB activation, which increased at 30 minutes (increased from 11.35+/-2.74 in the controls to 19.12+/-3.48, P<0.05) and thereafter increased steadily up to 4 hours after challenge (P<0.01). Concomitant with NF-kappaB activation, secretion of TNF-alpha and IL-8 in conidia-challenged cells was increased in a time-dependent manner. Incubation of THCE cells with TLR2 antibody or TLR4 antibody before conidia challenge resulted in inhibition of conidia-induced TNF-alpha and IL-8 secretion (P<0.05), TLR2 antibody and TLR4 antibody together significantly increased inhibition of the conidia-induced secretion of TNF-alpha and IL-8 from THCE cells (P<0.01).

CONCLUSIONAspergillus fumigatus conidia stimulates THCEs inflammatory response through a pathway dependent on TLR2 and TLR4 signaling.

Aspergillus fumigatus ; immunology ; Cells, Cultured ; Epithelium, Corneal ; cytology ; immunology ; Humans ; Interleukin-8 ; biosynthesis ; NF-kappa B ; metabolism ; Toll-Like Receptor 2 ; physiology ; Toll-Like Receptor 4 ; physiology ; Tumor Necrosis Factor-alpha ; biosynthesis

OBJECTIVETo study the effects of heat-killed Penicillium marneffei (PM) on the expressions of toll-like receptor-4 (TLR-4), toll-like receptor-2 (TLR-2) and dendritic cell associated C-type lectin-1 (Dectin-1)and the production of the proinflammatory cytokine tumor necrosis factor-alpha (TNF-alpha). in mouse peritoneal macrophages.

METHODSMouse peritoneal macrophages were cultured in the presence of heat-killed yeast-phase PM for 24 h, and the average fluorescence intensity of TLR-2, TLR-4, and Dectin-1 in the macrophages was detected using flow cytometry. Fluorescent staining of the macrophages was performed to observe the fluorescence of TLR-2, TLR-4, and Dectin-1 with confocal microscopy. TNF-alpha mRNA in the cell culture supernatant was measured with real-time PCR, and TNF-alpha protein detected using enzyme-linked immunosorbent assay (ELISA).

RESULTSThe average fluorescence intensity of TLR-2, TLR-4 and Dectin-1 in the macrophages was increased in response to a 24-h PM stimulation, and the stimulated macrophages produced large amounts of TNF-alpha.

CONCLUSIONPM up-regulates the expression of TLR-2, TLR-4 and Dectin-1 in mouse peritoneal macrophages, and their expressions are directly associated with macrophage activation.

Animals ; Cells, Cultured ; Lectins, C-Type ; Macrophages, Peritoneal ; cytology ; immunology ; metabolism ; Male ; Membrane Proteins ; biosynthesis ; Mice ; Mice, Inbred BALB C ; Nerve Tissue Proteins ; biosynthesis ; Penicillium ; immunology ; Toll-Like Receptor 2 ; biosynthesis ; Toll-Like Receptor 4 ; biosynthesis ; Tumor Necrosis Factor-alpha ; biosynthesis

OBJECTIVE: To determine the mechanism of Toll-like receptor 4(TLR4) in hypertensive renal injury and the protective effect of fosinopril(Fos) and losartan(Los). METHODS: NRK-52E was incubated into 5 groups: NRK-52E (normal control), NRK-52E+AngII, NRK-52E+AngII+Fos(10(-5) mmol/L),and NRK-52E+AngII+Los(10(-5) mmol/L), NRK-52E +AngII+Fos(10(-5) mmol/L)+Los(10(-5) mmol/L). TLR4-specific RNAi plasmids were stably transfected into NRK-52E. After 24 h, TLR4, IL-6, and TNF-alpha mRNAs were examined by reverse transcription-polymerase chain reaction(RT-PCR). TLR4 proteins were detected by Western blot, NF-kappaB nuclear translocations were tested by immunocytochemistry,and IL-6 and TNF-alpha supernatant levels were tested by enzyme linked immuno-sorbent assay(ELISA). RESULTS: TLR4, NF-kappaB, IL-6,and TNF-alpha were highly expressed in AngII induced NRK-52E(P<0.01). In NRK-52E that was stably transfected TLR4-special RNAi plamids, TLR4 protein and mRNA expression were obviously inhibited(P<0.05). After stimulation by AngII, the TLR4, IL-6, TNF-alpha levels in the stabe transfection group were increased compared with the normal group(P<0.05). Fos or/and Los down-regulated TLR4, IL-6, and TNF-alpha expressions(P<0.05), but no cooperation was observed. CONCLUSION TLR4 may lead to inflammatory reaction in hypertensive renal injury. Fos or/and Los can decrease the expressions of TLR4 and correlate inflammatory factors, which may be part of the renal protective mechanism.
Animals ; Cell Line ; Epithelial Cells ; immunology ; metabolism ; Fosinopril ; pharmacology ; Hypertension ; complications ; Kidney Diseases ; prevention & control ; Kidney Tubules ; cytology ; metabolism ; Losartan ; pharmacology ; RNA Interference ; RNA, Messenger ; biosynthesis ; genetics ; Rats ; Toll-Like Receptor 4 ; biosynthesis ; genetics

BACKGROUNDRestoration of blood flow to the ischemic liver lobes may paradoxically exacerbate tissue injury, which is called hepatic ischemia/reperfusion injury (IRI). Toll-like receptor 4 (TLR4), expressed on several liver cell types, and the nuclear factor-kappa B (NF-kappaB) signaling pathway are crucial to mediating hepatic inflammatory response. Because IRI is essentially a kind of profound acute inflammatory reaction evoked by many kinds of danger signals, we investigated TLR4/NF-kappaB signaling pathway activation in a murine model of partial hepatic IRI.

METHODSWild-type mice (WT, C3H/HeN) or TLR4 mutant mice (C3H/HeJ) were subjected to 45 minutes of partial hepatic ischemia followed by 1 hour, 3 hours of reperfusion. Sham group accepted the same procedure without the obstruction of blood supply. At the end of reperfusion, the compromise of liver function and the histological change of liver sections were measured as the severity of liver injury. The level of endotoxin in the portal vein was measured by limulus assay. NF-kappaB activation was determined by electrophoretic mobility shift assay (EMSA). The levels of tumor necrosis factor-alpha (TNF-alpha) and interleukin-1beta (IL-1beta) in systemic blood after hepatic IRI were assessed by enzyme-linked immunosorbent assay (ELISA).

RESULTSThe compromise of liver function and the morphological injuries in mutant mice were relieved more markedly than those in WT mice after partial hepatic IRI. NF-kappaB activation in WT mice was stronger than that in TLR4 mutant mice, and both were stronger than those in the sham operated mice (P < 0.01). Endotoxin in each group was undetectable. The levels of TNF-alpha and IL-1beta in systemic blood were elevated in both strains, but lower in the sham operated group. These mediators were significantly decreased in TLR4 mutant mice compared with those in WT mice (P < 0.01).

CONCLUSIONSThe TLR4/NF-kappaB signaling pathway may mediate hepatic IRI triggered by endogenous danger signals. Inhibition of the TLR4/NF-kappaB pathway may be a potential therapeutic target for attenuating ischemia/reperfusion-induced tissue damage in some clinical settings.

Alanine Transaminase ; blood ; Animals ; Interleukin-1beta ; biosynthesis ; Liver ; blood supply ; Mice ; Mice, Inbred C3H ; NF-kappa B ; physiology ; Reperfusion Injury ; etiology ; Signal Transduction ; physiology ; Toll-Like Receptor 4 ; physiology ; Tumor Necrosis Factor-alpha ; biosynthesis