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1: Acta oto-laryngologica. Supplementum, 2009 Jun, 64(562)
Poly(I:C) synergizes with Th2 cytokines to induce TARC/CCL17 in middle ear fibroblasts established from mucosa of otitis media with effusion.

[Abstract]CONCLUSION: These results suggest that middle ear fibroblasts contribute to the recruitment of Th2 cells into the middle ear by producing thymus and activation-regulated chemokine (TARC). OBJECTIVES: Intractable otitis media is more common in atopic subjects and asthmatics than in the otherwise normal population. Although type 2 T helper (Th2) cytokines play crucial roles in the middle ear of these populations, the mechanism underlying the predominance of Th2 cytokines has yet to be clarified. TARC has been known to facilitate recruitment of Th2 polarized cells, resulting in high levels of Th2 cytokines in the middle ear. We investigated whether middle ear-derived fibroblasts produce TARC when stimulated with poly(I:C) and Th2 cytokines (IL-4, IL-13). MATERIALS AND METHODS: Fibroblast lines were established from middle ear mucosa. TARC mRNA expression was evaluated by real-time RT-PCR. The amount of TARC in the culture supernatants was measured by ELISA. RESULTS: Poly(I:C) induced only TARC gene expression in middle ear-derived fibroblasts. Combined stimulation with poly(I:C) and Th2 cytokine (IL-4, IL-13) synergistically induced TARC production by the cultured middle ear-derived fibroblasts. This response was dose and time dependent.

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2: Respiratory research, 2009, 10(5)
Macrophage derived chemokine (CCL22), thymus and activation-regulated chemokine (CCL17), and CCR4 in idiopathic pulmonary fibrosis.

[Abstract]BACKGROUND: Idiopathic pulmonary fibrosis (IPF) is a chronically progressive interstitial lung disease of unknown etiology. Previously, we have demonstrated the selective upregulation of the macrophage-derived chemokine CCL22 and the thymus activation-regulated chemokine CCL17 among chemokines, in a rat model of radiation pneumonitis/pulmonary fibrosis and preliminarily observed an increase in bronchoalveolar (BAL) fluid CCL22 levels of IPF patients. METHODS: We examined the expression of CCR4, a specific receptor for CCL22 and CCL17, in bronchoalveolar lavage (BAL) fluid cells, as well as the levels of CCL22 and CCL17, to elucidate their pathophysiological roles in pulmonary fibrosis. We also studied their immunohistochemical localization. RESULTS: BAL fluid CCL22 and CCL17 levels were significantly higher in patients with IPF than those with collagen vascular diseases and healthy volunteers, and there was a significant correlation between the levels of CCL22 and CCL17 in patients with IPF. CCL22 levels in the BAL fluid did not correlate with the total cell numbers, alveolar lymphocytes, or macrophages in BAL fluid. However, the CCL22 levels significantly correlated with the numbers of CCR4-expressing alveolar macrophages. By immunohistochemical and immunofluorescence analysis, localization of CCL22 and CCR4 to CD68-positive alveolar macrophages as well as that of CCL17 to hyperplastic epithelial cells were shown. Clinically, CCL22 BAL fluid levels inversely correlated with DLco/VA values in IPF patients. CONCLUSION: We speculated that locally overexpressed CCL22 may induce lung dysfunction through recruitment and activation of CCR4-positive alveolar macrophages.

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3: Allergy, 2009 Jul, 64(7)
Blockade of CCR4 in a humanized model of asthma reveals a critical role for DC-derived CCL17 and CCL22 in attracting Th2 cells and inducing airway inflammation.

[Abstract]BACKGROUND: As Th2 type lymphocytes orchestrate the cardinal features of allergic asthma, inhibiting their recruitment to the lungs could be of therapeutic benefit. Although human Th2 cells express the CCR4 chemokine receptor and increased production of CCR4 ligands has been found in asthmatic airways, studies in animals have reached contradictory conclusions on whether blocking this pathway would be beneficial. OBJECTIVE: As a lack of efficacy might be due to differences between mouse and man, we readdressed this question using a humanized severe combined immunodeficiency model of asthma. METHODS: Mice received peripheral blood mononuclear cells from house dust mite (HDM) allergic asthmatic patients and then underwent bronchial challenge with HDM. RESULTS: This resulted in marked allergic inflammation and bronchial hyper-reactivity. Administration of CCR4 blocking antibody abolished the airway eosinophilia, goblet cell hyperplasia, IgE synthesis and bronchial hyper-reactivity. In this chimeric system, human CD11c+ dendritic cells (DCs) were the predominant source of CCR4 ligands, suggesting that DC-derived chemokines attract Th2 cells. In separate experiments using human DCs, in vitro exposure to HDM of DCs from HDM allergic patients but not healthy controls caused CCL17 and CCL22 release that resulted in chemoattraction of polarized human Th2 cells in a CCR4-dependent way. CONCLUSIONS: Taken together, our data provide proof of concept that CCR4 blockade inhibits the salient features of asthma and justify further clinical development of CCR4 antagonists for this disease.

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4: Biochemical and biophysical research communications, 2009 Sep 11, 387(1)
Suppression of thymus- and activation-regulated chemokine (TARC/CCL17) production by 1,2,3,4,6-penta-O-galloyl-beta-D-glucose via blockade of NF-kappaB and STAT1 activation in the HaCaT cells.

[Abstract]Keratinocytes, one of major cell types in the skin, can be induced by TNF-alpha and IFN-gamma to express thymus- and activation-regulated chemokine (TARC/CCL17), which is considered to be a pivotal mediator in the inflammatory responses during the development of inflammatory skin diseases, such as atopic dermatitis (AD). In this study, we examined the effect of 1,2,3,4,6-penta-O-galloyl-beta-d-glucose (PGG), isolated from the barks of Juglans mandshurica, on TNF-alpha/IFN-gamma induced CCL17 expression in the human keratinocyte cell line HaCaT. Pretreatment of HaCaT cells with PGG suppressed TNF-alpha/IFN-gamma-induced protein and mRNA expression of CCL17. PGG significantly inhibited TNF-alpha/IFN-gamma-induced NF-kappaB activation as well as STAT1 activation. Furthermore, pretreatment with PGG resulted in significant reduction in expression of CXCL9, 10, and 11 in the HaCaT cells treated with IFN-gamma. These results suggest that PGG may exert anti-inflammatory responses by suppressing TNF-alpha and/or IFN-gamma-induced activation of NF-kappaB and STAT1 in the keratinocytes and might be a useful tool in therapy of skin inflammatory diseases.

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5: Immunobiology, 2009 May 16, 46(10)
Targeted knock down of CCL22 and CCL17 by siRNA during DC differentiation and maturation affects the recruitment of T subsets.

[Abstract]Chemokines secreted by DC are instrumental for DC to regulate their own migratory capacities and to recruit T lymphocytes during local tumour immune response. Using the recently developed chemokine protein arrays, we analyzed 38 chemokines associated with monocyte-derived DC (MoDC), including the CC family (CCL2, CCL3, CCL4, CCL17, CCL18, CCL22, CCL23, CCL24, CCL27) and the CXC family (CXCL3, CXCL5, CXCL7, CXCL8, CXCL16) chemokines. Our results indicate that MoDC largely inherit the chemokines constitutively expressed by monocytes, with a significant induction of CCL17, CCL22 and CCL23. Spent culture supernatant collected from MoDC exhibited chemotatic abilities to activate CD4(+), CD8(+), and CD25(+) Foxp3(+) regulatory T cells (Tregs). Selective knock down of CCL22 and CCL17 expression by siRNA decreased the ratios of CD4(+) to CD8(+), as well as the frequency of Tregs recruited by MoDC. Intratumoural injection of MoDC transfected with siCCL22 and siCCL17, significantly reduced the number of Tregs while increasing the number of infiltrating CD8(+) T cells in human tumour xenografts in athymic nude mice. This study demonstrates that chemokine expression of MoDC is complex and may change dynamically. Using siRNA to selectively knock down chemokines which are highly chemoattractive to Tregs may consequentially alter the lymphocyte populations recruited into the tumour microenvironment, therefore has the potency to provide insight into cellular interactions in cancer immunology. This may lead to a new strategy for DC vaccine development to improve cancer immunobiotherapy.

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6: Journal of clinical immunology, 2009 Sep, 29(5)
Increases in serum TARC/CCL17 levels are associated with progression-free survival in advanced melanoma patients in response to dendritic cell-based immunotherapy.

[Abstract]INTRODUCTION: Changes in the levels of serum cytokines and growth factors are associated with response to therapy. We examined cytokine, chemokine, and growth factor levels in serum collected from normal volunteers or metastatic melanoma patients receiving dendritic cell-based immunotherapy. MATERIALS AND METHODS: Using an array for 42 cytokines, chemokines, or growth factors, sera from normal controls and metastatic melanoma patients at baseline and week 4 were analyzed for qualitative changes. Quantitative determination of the levels of the chemokine thymus and activation-regulated chemokine (TARC/CCL17) was determined by enzyme-linked immunosorbent assay (ELISA). RESULTS: Significant qualitative differences were noted in serum cytokine, chemokine, and growth factor levels of metastatic melanoma patients versus the normal controls at baseline. The results also demonstrated a significant decrease in the level of angiogenin (P = 0.026) and a significant increase in TARC/CCLl7 (P = 0.008) from week 0 to week 4 which was associated with improved overall survival (P = 0.059). Higher TARC/CCL17 levels were observed by ELISA at week 4 and a log-rank comparison revealed a significant association between high serum TARC/CCL17 levels at week 4 and progression-free survival (P = 0.005). Receiver-operator characteristic analysis revealed that week 4 serum TARC/CCL17 levels were predictive of progression-free and overall survival, indicating that serum TARC/CCL17 might be of predictive value of response to dendritic cell-based anti-melanoma immunotherapy.

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7: Molecular immunology, 2009 Jun, 46(10)
The adenylyl cyclase-cAMP system suppresses TARC/CCL17 and MDC/CCL22 production through p38 MAPK and NF-kappaB in HaCaT keratinocytes.

[Abstract]Patients with atopic dermatitis (AD) have significantly reduced plasma cAMP levels, and the cAMP level is correlated with the immunopathogenesis of AD. The production of thymus and activation-regulated chemokine (TARC/CCL17) and macrophage-derived chemokine (MDC/CCL22) in keratinocytes is significantly enhanced in patients with AD. In the present study, we investigated the in vitro effects of the adenylyl cyclase-cAMP system on IFN-gamma and TNF-alpha-stimulated production of TARC and MDC in human HaCaT keratinocytes. Both forskolin (a direct activator of adenylyl cyclase) and dibutyryl-cAMP (DBcAMP, a permeable analog of cAMP) suppressed production of TARC and MDC in parallel with the activation of NF-kappaB in IFN-gamma and TNF-alpha-stimulated HaCaT cells. Moreover, inhibition of NF-kappaB suppressed TARC and MDC production induced by IFN-gamma plus TNF-alpha. However, dideoxyforskolin, a forskolin derivative that does not activate cAMP, failed to suppress the secretion of these chemokines. An inhibitor of p38 MAPK suppressed the production of TARC and MDC in parallel to the activation of NF-kappaB in HaCaT cells. Of note, the IFN-gamma plus TNF-alpha-stimulated activation of p38 MAPK was suppressed following incubation with forskolin or DBcAMP alone. These results indicate that the adenylyl cyclase-cAMP system has an inhibitory role in IFN-gamma plus TNF-alpha-stimulated production of TARC and MDC in HaCaT keratinocytes by inhibiting NF-kappaB activation through p38 MAPK pathway, implying that the adenylyl cyclase-cAMP system could be a candidate therapeutic target of Th2-skewed skin inflammation such as AD.

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8: British journal of haematology, 2008 Mar, 140(5)
Serum chemokine levels in Hodgkin lymphoma patients: highly increased levels of CCL17 and CCL22.

[Abstract]Hodgkin lymphoma (HL) is characterized by a minority of neoplastic Hodgkin-Reed Sternberg (HRS) cells surrounded by a non-neoplastic reactive infiltrate. As immunological mechanisms appear to be crucial in classical HL pathogenesis, altered serum chemokine levels might be related to disease activity. Serum levels of nine chemokines were examined in 163 untreated HL patients and 334 controls. We investigated single nucleotide polymorphisms (SNPs) for association with serum CCL17 (thymus and activation-regulated chemokine, TARC) levels and HL susceptibility. Serum CCL17 and CCL22 (macrophage-derived chemokine, MDC) levels were significantly increased in 82% and 57% of the HL patients. Nodular sclerosis cases showed increased serum CCL17 and CCL22 levels (P < 0.001) and serum levels were correlated with Ann Arbor stage. Of nine patients with pre- and post-treatment serum samples, the majority showed decreased CCL17 and CCL22 levels after treatment. HRS cells expressed CCL17 and CCL22 in 77% and 75% of 74 cases. Three SNPs showed a trend of increased serum CCL17 levels with minor alleles in controls, but were not associated with HL susceptibility. CCL17 and CCL22 were the only chemokines with increased serum levels in the vast majority of HL patients, which provides further insight into the molecular mechanism(s) leading to infiltrations of reactive lymphocytes in HL.

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9: International journal of cancer. Journal international du cancer, 2008 May 15, 122(10)
CCL17 and CCL22 chemokines within tumor microenvironment are related to accumulation of Foxp3+ regulatory T cells in gastric cancer.

[Abstract]It has been reported that an increased population of regulatory T cells (Tregs) is one of the reasons for impaired anti-tumor immunity. Recently, Foxp3 has been reported as a reliable marker of Tregs. The authors investigated the frequency of Foxp3(+) Tregs within CD4(+) cells in TILs, regional lymph nodes and PBLs of gastric cancer patients (n = 45). Furthermore, to elucidate the mechanisms behind Treg accumulation within tumors, they evaluated the relationship between CCL17 or CCL22 expression and the frequency of Foxp3(+) Tregs in gastric cancer. CD4(+)CD25(+)Foxp3(+) Tregs as a percentage of CD4(+) cells were counted by flow cytometry and evaluated by immunohistochemistry. Moreover, an in vitro migration assay using Tregs derived from gastric cancers was performed in the presence of CCL17 or CCL22. As a result, the frequency of Foxp3(+) Tregs in TILs was significantly higher than that in normal gastric mucosa (12.4% +/- 7.5% vs. 4.1% +/- 5.3%, p < 0.01). Importantly, the increase in Tregs in TILs occurred to the same extent in early and advanced disease. Furthermore, the frequency of CCL17(+) or CCL22(+) cells among CD14(+) cells within tumors was significantly higher than that of normal gastric mucosa, and there was a significant correlation between the frequency of CCL17(+) or CCL22(+) cells and Foxp3(+) Tregs in TILs. In addition, the in vitro migration assay indicated that Tregs were significantly induced to migrate by CCL17 or CCL22. In conclusion, CCL17 and CCL22 within the tumor are related to the increased population of Foxp3(+) Tregs, with such an observation occurring in early gastric cancer.

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10: Human immunology, 2007 Dec, 68(12)
Identification of a distal tandem STAT6 element within the CCL17 locus.

[Abstract]The CC chemokine ligand CCL17 is one of the major chemo-attractants for T(H)2 cells. Interleukin-4-induced activation of CCL17 expression was recently demonstrated to result from two STAT6 motifs in the proximal promoter. Here we provide evidence that a distal tandem STAT6 element further elevates expression from the CCL17 locus approximately twofold. This is demonstrated by reporter gene assays using different fragments of the CCL17 promoter and the region 2.5 kb upstream from the transcriptional start site. By electrophoretic mobility shift assay (EMSA) and chromatin immunoprecipitation experiments, we show that STAT6 binds to the motifs in vitro and in vivo, respectively. Insertion of nucleotide exchanges into the STAT6 core motifs results in diminished promoter activation and abrogated STAT6 binding, as demonstrated by reporter gene and EMSA studies. Collectively these data reveal an additional element involved in the regulation of CCL17 expression.

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11: Journal of interferon & cytokine research : the official journal of the International Society for Interferon and Cytokine Research, 2007 Nov, 27(11)
Expression of chemokine receptor CCR4 and its ligands (CCL17 and CCL22) in murine contact hypersensitivity.

[Abstract]Chemokine receptor CCR4 and its ligands (CCL17 and CCL22) are important for the recruitment of memory T cells into the skin in various cutaneous immune diseases. However, information on CCR4 and its ligands in contact hypersensitivity is relatively limited. In this study, we investigated the expression of CCR4, CCL17, and CCL22 in a mouse model of contact hypersensitivity to oxazolone. Contact sensitization to oxazolone increased the proportions of memory CD4+ T cells in the draining lymph nodes, spleen, and peripheral blood. Although CCR4+ mRNA and CCR4+ cells were detectable in naive mouse lymph nodes, they significantly increased in the sensitized mice. The majority of CCR4+ cells in both control and sensitized mouse lymph nodes were CD4+ T cells. In the skin of naive mice, the mRNAs for CCR4, CCL17, and CCL22 were detectable, but only CCL17 and CCL22 proteins were constitutively expressed in the skin, particularly in the epidermis. Interestingly, the mRNAs for CCR4 and its two ligands were significantly elevated in the inflamed skin of mice with contact hypersensitivity to oxazolone. Furthermore, a subpopulation of cells that infiltrated the skin was CCR4+ cells. Finally, the expression of CCL17 and CCL22 proteins was significantly enhanced in the epidermis of inflamed skin. Thus, our study provides direct evidence for the presence of CCR4 and its ligands in mouse contact hypersensitivity.