OBJECTIVE

Inflammatory bowel disease (IBD) is characterized by a continuous influx of leukocytes into the gut wall. This migration is regulated by cell adhesion molecules (CAMs), and selective antimigration therapies have been developed. This study investigated the effect of infliximab therapy on the mucosal gene expression of CAMs in IBD.

METHODS

Mucosal gene expression of 69 leukocyte/endothelial CAMs and E-cadherin was investigated in 61 IBD patients before and after first infliximab infusion and in 12 normal controls, using Affymetrix gene expression microarrays. Quantitative reverse transcriptase-PCR (qRT-PCR), immunohistochemistry, and western blotting were used to confirm the microarray data.

RESULTS

When compared with control colons, the colonic mucosal gene expression of most leukocyte/endothelial adhesion molecules was upregulated and E-cadherin gene expression was downregulated in active colonic IBD (IBDc) before therapy, with no significant colonic gene expression differences between ulcerative colitis and colonic Crohn's disease. Infliximab therapy restored the upregulations of leukocyte CAMs in IBDc responders to infliximab that paralleled the disappearance of the inflammatory cells from the colonic lamina propria. Also, the colonic gene expression of endothelial CAMs and of most chemokines/chemokine receptors returned to normal after therapy in IBDc responders, and only CCL20 and CXCL1-2 expression remained increased after therapy in IBDc responders vs. control colons. When compared with control ileums, the ileal gene expression of MADCAM1, THY1, PECAM1, CCL28, CXCL1, -2, -5, -6, and -11, and IL8 was increased and CD58 expression was decreased in active ileal Crohn's disease (CDi) before therapy, and none of the genes remained dysregulated after therapy in CDi responders vs. control ileums. This microarray study identified a number of interesting targets for antiadhesion therapy including PECAM1, IL8, and CCL20, besides the currently studied α4β7 integrin-MADCAM1 axis.

CONCLUSIONS

Our data demonstrate that many leukocyte/endothelial CAMs and chemokines/chemokine receptors are upregulated in inflamed IBD mucosa. Controlling the inflammation with infliximab restores most of these dysregulations in IBD. These results show that at least part of the mechanism of anti-tumor necrosis factor-α therapy goes through downregulation of certain adhesion molecules.

MicroRNA 21 (miR-21) has been implicated in various aspects of carcinogenesis. However, its function and molecular mechanism in cervical squamous carcinoma have not been studied. Using TaqMan quantitative real-time PCR and Northern blot, we confirmed that miR-21 is significantly overexpressed in human cervical squamous cancer tissues and cell lines. Remarkably, we showed that the level of miR-21 correlates with the tumor differentiation and nodal status by ISH. Furthermore, we demonstrated that miR-21 regulates proliferation, apoptosis, and migration of HPV16-positive cervical squamous cells. In order to identify candidate target genes for miR-21, we used gene expression profiling. By luciferase reporter assays, we confirmed that CCL20 is one of its target genes, which is related to the HPV16 E6 and E7 oncogenes. Our results suggest that miR-21 may be involved in cervical squamous cell tumorigenesis.

Mesenchymal stem cells (MSCs) have anti-inflammatory and immunosuppressive properties and may be useful in the therapy of diseases such as arteriosclerosis. MSCs have some ability to traffic into inflamed tissues, however to exploit this therapeutically their migratory mechanisms need to be elucidated. This study examines the interaction of murine MSCs (mMSCs) with, and their migration across, murine aortic endothelial cells (MAECs), and the effects of chemokines and shear stress. The interaction of mMSCs with MAECs was examined under physiological flow conditions. mMSCs showed lack of interaction with MAECs under continuous flow. However, when the flow was stopped (for 10 min) and then started, mMSCs adhered and crawled on the endothelial surface, extending fine microvillous processes (filopodia). They then spread extending pseudopodia in multiple directions. CXCL9 significantly enhanced the percentage of mMSCs adhering, crawling and spreading and shear forces markedly stimulated crawling and spreading. CXCL9, CXCL16, CCL20 and CCL25 significantly enhanced transendothelial migration across MAECs. The transmigrated mMSCs had down-regulated receptors CXCR3, CXCR6, CCR6 and CCR9. This study furthers the knowledge of MSC transendothelial migration and the effects of chemokines and shear stress which is of relevance to inflammatory diseases such as arteriosclerosis.

Various chemokine receptors, namely CXCR4, CCR6 and CCR7, have recently been shown to be involved in the regulation of metastasis in malignant tumors. However, little is known about the role of these receptors in promoting tumor metastasis of colorectal cancer (CRC) to the primary site of CRC metastasis in the liver. To investigate this issue, we analyzed the expression of the chemokine receptors CXCR4, CCR6 and CCR7 in colorectal tumors and colorectal liver metastases. In the present study, 30 human cancer samples from colorectal tissue, 30 human samples from colorectal liver metastases and the adjacent nontumorous liver tissues were screened using quantitative real-time PCR, Western blot analysis, histochemistry, microdissection and the enzyme-linked immunosorbent assay (ELISA). While an overexpression of all the chemokine receptors was found in CRC, in colorectal liver metastases only the chemokine receptors CXCR4 and CCR6 were significantly upregulated. Consequently, we investigated the expression of the corresponding ligands CXCL12/SDF1alpha, CCL20/MIP3alpha, CCL19/MIP3beta and CCL21/6Ckine in various organs, such as the stomach, esophagus, pancreas, colon and rectum, in comparison with their expression in the liver as the primary site of metastatic spread in CRC. We found that only CCL20 exhibits peak levels of expression in the liver, thus indicating that an increased production of CCL20 may contribute to the selective recruitment of CCR6-expressing cancer cells in CRC. Furthermore, we could demonstrate that CRC patients who developed liver metastases express significantly more CCL20 and CCL21 in the liver in comparison with an unaffected control group. Therefore, our findings strongly suggest an association between CCL20/CCR6 expression in human CRC and the promotion of colorectal liver metastasis.

BACKGROUND

There is growing evidence that resident cells, such as fibroblasts and epithelial cells, can drive the persistent accumulation of dendritic cells (DCs) in chronically inflamed tissue, leading to the organization and the maintenance of ectopic lymphoid aggregates. This phenomenon, occurring through a chemokine-mediated retention mechanism, has been documented in various disorders, but not in fibrotic interstitial lung disorders in which the presence of organized lymphoid follicles has been documented.

OBJECTIVE

To characterize the distribution of DCs in fibrotic lung, and to analyze the expression of the main chemokines known to regulate DC recruitment.

METHODS

Lung resection tissue (lungs with idiopathic pulmonary fibrosis; n = 12; lungs with nonspecific interstitial pneumonia, n = 5; control lungs, n = 5) was snap-frozen for subsequent immunohistochemical techniques on serial sections and reverse transcriptase-polymerase chain reaction analysis.

RESULTS

Results were similar in idiopathic pulmonary fibrosis and nonspecific interstitial pneumonia lungs, which were heavily infiltrated by immature DCs in established fibrosis and in areas of epithelial hyperplasia. Altered epithelial cells and fibroblasts, particularly in fibroblastic foci, frankly expressed all chemokines (CCL19, CCL20, CCL22, and CXCL12) susceptible to favor the recruitment of immune cells. Lymphoid follicles were infiltrated by maturing DCs, which could originate from the pool of DCs accumulating in their vicinity.

CONCLUSIONS

These findings suggest that resident cells in pulmonary fibrosis can sustain chronic inflammation by driving the accumulation of DCs with the potential to mature locally within ectopic lymphoid follicles. Future strategies should consider DCs or chemokines as therapeutic targets in the treatment of pulmonary fibrosis.

We studied the production of interleukin (IL)-6 and CCL20/macrophage inflammatory protein-3 alpha (MIP-3 alpha) by human myoblasts and muscle samples in response to IL-17 alone or in combination with IL-1 beta. Both IL-17 and IL-1 beta induced IL-6 production by normal myoblasts and muscle samples. IL-17 had no effect on CCL20 production by myoblasts. Combination of IL-17 and IL-1 beta further increased IL-6 and CCL20 production by muscle samples but not that of CK. IL-17 induced also HLA class I, C-Fos, nuclear factor kappa B (NF-kappa B) and C-Jun expression by myoblasts but not that of HLA class II, CD40, vascular cell adhesion molecule 1 (VCAM-1) and intercellular adhesion molecule 1 (ICAM-1). Finally, immunostaining of dermatomyositis (DM) and polymyositis (PM) muscle biopsies showed IL-17 and CCL20 expression. Our study shows that low levels of cytokines produced by T cells (IL-17) and monocytes (IL-1 beta) can act in combination on skeletal myoblasts and muscle tissue.

The tumor microenvironment in pancreatic ductal adenocarcinoma (PDAC) is dynamic, with an extensive interaction between the stroma and tumor cells. The aim of this study was to delineate the cross talk between PDAC and cancer-associated fibroblasts (CAFs), with a focus on the mechanism creating the chronic inflammatory tumor milieu. We assessed the effects of the cross talk between PDAC and CAF cell lines on the creation and sustenance of the inflammatory tumor microenvironment in pancreatic cancer. The coculture of PDAC and CAF cell lines enhanced the levels of inflammatory factors including IL-1α, IL-6, CXCL8, VEGF-A, CCL20, and COX-2. CAFs were superior to tumor cells regarding the production of most inflammatory factors, and tumor cell-associated IL-1α was established as the initiator of the enhanced production of inflammatory factors through the binding of IL-1α to IL-1 receptor 1 (IL-1R1) expressed predominantly by CAFs. Furthermore, we found a correlation between IL-1α and CXCL8 expression levels in PDAC tissues and correlation between IL-1α expression and the clinical outcome of the patients. This confirmed an important role for the IL-1 signaling cascade in the creation and sustenance of a tumor favorable microenvironment. Neutralization of the IL-1α signaling efficiently diminished the cross talk-induced production of inflammatory factors. These data suggest that the cross talk between PDAC cells and the main stroma cell type, i.e. CAFs, is one essential factor in the formation of the inflammatory tumor environment, and we propose that neutralization of the IL-1α signaling might be a potential therapy for this cancer.

BACKGROUND

Gastric cancer is one of the common cancers seen in south India. Unfortunately more than 90% are advanced by the time they report to a tertiary centre in the country. There is an urgent need to characterize these cancers and try to identify potential biomarkers and novel therapeutic targets.

METHODS

We used 24 gastric cancers, 20 Paired normal (PN) and 5 apparently normal gastric tissues obtained from patients with non-gastric cancers (Apparently normal - AN) for the microarray study followed by validation of the significant genes (n = 63) by relative quantitation using Taqman Low Density Array Real Time PCR. We then used a custom made Quantibody protein array to validate the expression of 15 proteins in gastric tissues (4 AN, 9 PN and 9 gastric cancers). The same array format was used to study the plasma levels of these proteins in 58 patients with gastric cancers and 18 from patients with normal/non-malignant gastric conditions.

RESULTS

Seventeen genes (ASPN, CCL15/MIP-1δ, MMP3, SPON2, PRSS2, CCL3, TMEPAI/PMEPAI, SIX3, MFNG, SOSTDC1, SGNE1, SST, IGHA1, AKR1B10, FCGBP, ATP4B, NCAPH2) were shown to be differentially expressed between the tumours and the paired normal, for the first time. EpCAM (p = 0.0001), IL8 (p = 0.0003), CCL4/MIP-1β (p = 0.0026), CCL20/MIP-3α (p = 0.039) and TIMP1 (p = 0.0017) tissue protein levels were significantly different (Mann Whitney U test) between tumours versus AN & PN. In addition, median plasma levels of IL8, CXCL9/MIG, CCL3/MIP-1α, CCL20/MIP-3α, PDGFR-B and TIMP1 proteins were significantly different between the non-malignant group and the gastric cancer group. The post-surgical levels of EpCAM, IGFBP3, IL8, CXCL10/IP10, CXCL9/MIG, CCL3/MIP-1α, CCL20/MIP-3α, SPP1/OPN and PDGFR-B showed a uniform drop in all the samples studied.

CONCLUSIONS

Our study has identified several genes differentially expressed in gastric cancers, some for the first time. Some of these have been confirmed at the protein level, as well. Some of these proteins will need to be evaluated further for their potential as diagnostic biomarkers in gastric cancers and some could be useful as follow-up markers in gastric cancer.

In the adult central nervous system (CNS), chemokines and their receptors are involved in developmental, physiological and pathological processes. Although most lines of investigation focus on their ability to induce the migration of cells, recent studies indicate that chemokines also promote cellular interactions and activate signaling pathways that maintain CNS homeostatic functions. Many homeostatic chemokines are expressed on the vasculature of the blood brain barrier (BBB) including CXCL12, CCL19, CCL20, and CCL21. While endothelial cell expression of these chemokines is known to regulate the entry of leukocytes into the CNS during immunosurveillance, new data indicate that CXCL12 is also involved in diverse cellular activities including adult neurogenesis and neuronal survival, having an opposing role to the homeostatic chemokine, CXCL14, which appears to regulate synaptic inputs to neural precursors. Neuronal expression of CX3CL1, yet another homeostatic chemokine that promotes neuronal survival and communication with microglia, is partly regulated by CXCL12. Regulation of CXCL12 is unique in that it may regulate its own expression levels via binding to its scavenger receptor CXCR7/ACKR3. In this review, we explore the diverse roles of these and other homeostatic chemokines expressed within the CNS, including the possible implications of their dysfunction as a cause of neurologic disease.

Dendritic cells (DC) are a heterogeneous family of cells that function as sentinels of the immune system. This article summarizes observations suggesting that inflammatory chemokines secreted at the site of pathogen invasion determine the DC subset recruited and influence the class of the immune response initiated. Langerhans cells are selectively recruited by MIP-3alpha/CCL20. In contrast, CCR7 ligands have a key role in the accumulation of antigen-loaded mature DC in T cell-rich areas of the draining lymph node. Improved understanding of the regulation of DC trafficking might offer new opportunities for therapeutic interventions to control immune responses.

OBJECTIVE

CCL20, also known as MIP-3 alpha, is a chemokine that participates in chemotaxis of immature dendritic cells, effector/memory T-cells, and B-lymphocytes. The objectives of this study were to determine whether CCL20 can be detected in amniotic fluid (AF) and if AF concentration of this chemokine changes with advancing gestational age, parturition (term and preterm), and intra-amniotic infection/inflammation (IAI).

METHODS

A cross-sectional study was conducted including the following groups: (1) mid-trimester of pregnancy (n=65); (2) term not in labor (TNL; n=22); (3) term in labor (TIL; n=47); (4) spontaneous preterm labor (PTL) who delivered at term (n=57); (5) spontaneous PTL without IAI who delivered preterm (n=71); and (6) spontaneous PTL with IAI (n=38). AF CCL20 concentrations were determined using ELISA.

RESULTS

(1) The median AF CCL20 concentration in TNL was higher than that of mid-trimester patients; (2) Women in spontaneous labor at term had a higher median AF concentration of CCL20 than patients at term not in labor; (3) Patients with spontaneous PTL and IAI had a significantly higher median AF concentration of CCL20 than those without IAI who delivered preterm and those who delivered at term. Moreover, women with spontaneous PTL without IAI who delivered preterm had a significantly higher median AF concentration than those with PTL who subsequently delivered at term.

CONCLUSIONS

(1) CCL20 is a physiologic constituent of AF and its concentration increases as term approaches; (2) spontaneous labor (term and preterm) in the absence of IAI is associated with increased bioavailability of AF CCL20 suggesting that an increase in CCL20 is part of the common pathway of human parturition; (3) patients with IAI had dramatic elevations in the AF CCL20 concentrations suggesting that this chemokine participates in the host response to infection or other stimuli associated with intra-amniotic infection.

S100A8 and S100A9 are known to be up-regulated in hyperproliferative and psoriatic epidermis, but their function in epidermal keratinocytes remains largely unknown. Here we show that (1) S100A8 and S100A9 are secreted by cultured normal human keratinocytes (NHK) in a cytokine-dependent manner, (2) when applied to NHK, recombinant S100A8/A9 (a 1:1 mixture of S100A8 and S100A9) induced expression of a number of cytokine genes such as IL-8/CXCL8, CXCL1, CXCL2, CXCL3, CCL20, IL-6, and TNFalpha that are known to be up-regulated in psoriatic epidermis, (3) the S100A8/A9-induced cytokines in turn enhanced production and secretion of S100A8 and S100A9 by NHK, and (4) S100A8 and S100A8/A9 stimulated the growth of NHK at a concentration as low as 1 ng/ml. These results indicate the presence of a positive feedback loop for growth stimulation involving S100A8/A9 and cytokines in human epidermal keratinocytes, implicating the relevance of the positive feedback loop to the etiology of hyperproliferative skin diseases, including psoriasis.

BACKGROUND

The meniscus plays critical roles in the knee, contributing to load transmission, shock absorption, and joint stability. Little is known about gene expression in meniscal tears, particularly in relation to injury pattern and patient age and sex. The purpose of this study was to test the hypothesis that gene expression in meniscal tears varies depending on patient age and sex and whether the anterior cruciate ligament (ACL) is also torn.

METHODS

Meniscal tissue from twenty-eight patients with an isolated meniscal tear or a meniscal tear with a concomitant ACL tear was collected at the time of clinically indicated partial meniscectomy. Messenger RNA (mRNA) expression was examined by quantitative real-time polymerase chain reaction for molecular markers of osteoarthritis including proinflammatory cytokines (interleukin [IL]-1α, IL-1β, IL-6, and tumor necrosis factor-alpha [TNFα]), chemokines (IL-8, CCL3, CCL3L1, CXCL1, CXCL3, CXCL6, and CCL20), aggrecanases (ADAMTS-4 [a disintegrin and metalloproteinase with thrombospondin type-4 motifs] and ADAMTS-5), matrix metalloproteinases (MMP-1, MMP-3, MMP-9, and MMP-13), transcription factors (NFκB2 [nuclear factor kappa B2], NFκBIA [NF-kappa B inhibitor alpha], and IκBA [inhibitor of kappa B alpha]), and matrix components (bone morphogenetic protein [BMP]-2, type-I collagen alpha 1 [Col1a1], Col2a1, and aggrecan).

RESULTS

Expression of IL-1β (p = 0.02), ADAMTS-5 (p = 0.001), MMP-1 (p = 0.007), MMP-9 (p = 0.002), MMP-13 (p = 0.01), and NFκB2 (p = 0.01) was significantly higher in patients with a meniscal tear who were under the age of forty years than it was in those over the age of forty years. Similarly, the expression of ADAMTS-4 (p = 0.002), ADAMTS-5 (p = 0.02), MMP-1 (p = 0.02), and MMP-13 (p = 0.0002) was higher in patients with a meniscal tear and an ACL tear who were under the age of forty years than it was in those over forty years. In patients with a meniscal tear and an ACL tear, the expression of IL-1β (p = 0.01), TNFα (p = 0.02), MMP-13 (p = 0.004), CCL3 (p = 0.03), and CCL3L1 (p = 0.03) was significantly higher, while that of aggrecan (p = 0.03) was lower, than that in patients with a meniscal tear alone. The only sex-based difference in gene expression was higher levels of CCL3L1 in female patients (p < 0.05) of all ages with combined injuries.

CONCLUSIONS

These findings suggest clinically relevant differences in the response of the knee to meniscal tears on the basis of patient age and sex. Elevated expression levels of arthritis-related markers indicate an increased catabolic response in patients under forty years old. Higher expression of catabolic markers in patients with meniscal and ACL tears suggests this combined injury pattern is more likely to lead to the development of osteoarthritis. Catabolic activity in meniscal tissue may predict patients who are at risk for progression of osteoarthritis following partial meniscectomy.

After birth, the respiratory tract adapts to recurrent exposures to pathogens, allergens, and toxicants by inducing the complex innate and acquired immune systems required for pulmonary homeostasis. In this study, we show that Foxa2, expressed selectively in the respiratory epithelium, plays a critical role in regulating genetic programs influencing Th2 cell-mediated pulmonary inflammation. Deletion of the Foxa2 gene, encoding a winged helix/forkhead box transcription factor that is selectively expressed in respiratory epithelial cells, caused spontaneous pulmonary eosinophilic inflammation and goblet cell metaplasia. Loss of Foxa2 induced the recruitment and activation of myeloid dendritic cells and Th2 cells in the lung, causing increased production of Th2 cytokines and chemokines. Loss of Foxa2-induced expression of genes regulating Th2 cell-mediated inflammation and goblet cell differentiation, including IL-13, IL-4, eotaxins, thymus and activation-regulated chemokine, Il33, Ccl20, and SAM pointed domain-containing Ets transcription factor. Pulmonary inflammation and goblet cell differentiation were abrogated by treatment of neonatal Foxa2(Delta/Delta) mice with mAb against IL-4Ralpha subunit. The respiratory epithelium plays a central role in the regulation of Th2-mediated inflammation and innate immunity in the developing lung in a process regulated by Foxa2.

The aggressiveness of invasive ductal carcinoma (IDC) of the breast is associated with increased IL17 levels. Studying the role of IL17 in invasive breast tumor pathogenesis, we found that metastatic primary tumor-infiltrating T lymphocytes produced elevated levels of IL17, whereas IL17 neutralization inhibited tumor growth and prevented the migration of neutrophils and tumor cells to secondary disease sites. Tumorigenic neutrophils promote disease progression, producing CXCL1, MMP9, VEGF, and TNFα, and their depletion suppressed tumor growth. IL17A also induced IL6 and CCL20 production in metastatic tumor cells, favoring the recruitment and differentiation of Th17. In addition, IL17A changed the gene-expression profile and the behavior of nonmetastatic tumor cells, causing tumor growth in vivo, confirming the protumor role of IL17. Furthermore, high IL17 expression was associated with lower disease-free survival and worse prognosis in IDC patients. Thus, IL17 blockade represents an attractive approach for the control of invasive breast tumors.

Chronic inflammation is an important underlying condition for ovarian tumor development, growth and progression. Since chemokine networks are activated by inflammation, patterns of chemokine gene expression were investigated in ovarian cancer cells. Chemokine specific microarrays were performed after mouse (ID8) and human (SKOV-3) ovarian surface epithelial cancer cells were exposed to the inflammatory agent bacterial endotoxin lipopolysaccharide (LPS, 10 microg/ml) and pro-inflammatory cytokines interleukin-1beta (IL-1, 10 ng/ml) and tumor necrosis factor-alpha (TNF, 10 ng/ml). In the mouse ID8 cells, LPS, IL-1 and TNF led to robust upregulation of keratinocyte chemoattractant (KC) chemokines CXCL1/2, mouse homologues of human growth-regulated oncogenes (GRO). Other chemokines, interferong inducible protein (IP)-10 (CXCL10), CCL7 and CCL20 were moderately upregulated. ID8 cells constitutively expressed CXCL16 and CCL2, but only CCL2 expression was enhanced by LPS, IL-1 and TNF. In the human SKOV-3 cells, LPS had no effect on chemokines expression due to the absence of the LPS receptor, toll-like receptor 4 (TLR4). However, IL-1 and TNF induced GROalpha/beta (CXCL1/2) in human SKOV-3 cells in a similar manner as observed with mouse ID8 cells. In SKOV-3 cells, IL-8 (CXCL8) was highly expressed and other chemokines GROgamma (CXCL3) and CCL20 were moderately expressed in response to IL-1 and TNF. The nuclear factor-kappaB (NF-kappaB) is a known mediator of cytokine and chemokines signaling. The NFkappaB inhibitor BAY 11-7082 attenuated expression of inflammatory-induced chemokines in the mouse and human ovarian cancer cells. Taken together, the results indicate that KC/GRO chemokines are the principal chemokines induced by LPS and pro-inflammatory cytokines IL-1 and TNF via NFkappaB signaling in ovarian surface epithelial cancer cells.

BACKGROUND

Accumulation of B cells in the rheumatoid arthritis (RA) synovium has been reported, and it has been thought that these cells might contribute to the pathogenesis of RA by antigen presentation, autoantibody production, and/or inflammatory cytokine production. Chemokines could enhance the accumulation of B cells in the synovium. The aims of this study were to determine chemokine receptor expression by B cells both in the peripheral blood of normal donors and subjects with RA, and at the inflammatory site in RA, and the effects of chemokines on B cell activation.

METHODS

Cell surface molecule expression was analyzed by flow cytometry. Cellular migration was assessed using chemotaxis chambers. Cellular proliferation was examined by 3H-thymidine incorporation. Tumor necrosis factor (TNF) production was assayed by enzyme-linked immunosorbent assay.

RESULTS

Significant numbers of peripheral blood B cells of healthy donors and subjects with RA expressed CC chemokine receptor (CCR)5 and CXCR3, and most B cells expressed CCR6, CCR7, CXCR4 and CXCR5. CCR5 expression was more frequent on CD27+ than CD27- peripheral blood B cells of healthy donors and RA. Synovial B cells more frequently expressed CCR5, but less often expressed CCR6, CCR7 and CXCR5 compared to peripheral blood in RA. Further functional analyses were performed on peripheral blood B cells from healthy donors. Migration of peripheral blood B cells, especially CD27+ B cells, was enhanced by CC chemokine ligand (CCL)20, CCL19, CCL21 and CXCL12. All four chemokines alone induced B cell proliferation; with CCL21 being the most effective. CCL21 also enhanced the proliferation of anti-immunoglobulin (Ig)M-stimulated B cells and blockade of CCR7 inhibited this effect. CCL20, CCL21 and CXCL12 enhanced TNF production by anti-IgM mAb-stimulated B cells. Finally, stimulation with CXCL12, but not CCL20, CCL19 and CCL21, enhanced inducible costimulator-ligand (ICOSL) expression by peripheral blood B cells of healthy donors and RA, but did not increase B cell-activating factor receptor or transmembrane activator and CAML-interactor.

CONCLUSIONS

The data suggest that CCR5, CCR6, CCR7, CXCR3, CXCR4 and CXCR5 may be important for the B cell migration into the synovium of RA patients, and also their local proliferation, cytokine production and ICOSL expression in the synovium.

Listeria monocytogenes is a Gram-positive bacterium that can cause septicemia and meningitis. TLRs are central receptors of the innate immune system that drive inflammatory responses to invading microbes such as L. monocytogenes. Although intestinal epithelial cells (IECs) represent the initial point of entry used by L. monocytogenes for infection, the innate immune response to L. monocytogenes in these cells has been poorly characterized to date. The aim of this study was to determine which TLRs are involved in mediating the immune response to L. monocytogenes in IECs. We performed an RNA interference screen of TLRs 1-10 in the HT-29 IEC cell line and observed the most significant reduction in chemokine output following silencing of TLR10. This effect was also observed in the macrophage cell line THP-1. The chemokines CCL20, CCL1, and IL-8 were reduced following knockdown of TLR10. Silencing of TLR10 resulted in increased viability of L. monocytogenes in both HT-29 and THP-1 cells. TLR10 was found to be predominantly expressed intracellularly in epithelia, and activation required viable L. monocytogenes. NF-κB activation was seen to require TLR2 in addition to TLR10. Taken together, these data indicate novel roles for TLR10 in sensing pathogenic infection in both the epithelium and macrophages and have identified L. monocytogenes as a source of ligand for the orphan receptor TLR10.

Despite the long-appreciated in vivo role of the redox-active virulence factor pyocyanin in Pseudomonas airway infections and the importance of airway epithelial cells in combating bacterial pathogens, little is known about pyocyanin's effect on airway epithelial cells. We find that exposure of bronchiolar epithelial cells to pyocyanin results in MUC2/MUC5AC induction and mucin secretion through release of inflammatory cytokines and growth factors (interleukin (IL)-1β, IL-6, heparin-bound epidermal growth factor, tissue growth factor-α, tumor necrosis factor-α) that activate the epidermal growth factor receptor pathway. These changes are mediated by reactive oxygen species produced by pyocyanin. Microarray analysis identified 286 pyocyanin-induced genes in airway epithelial cells, including many inflammatory mediators elevated in cystic fibrosis (granulocyte colony-stimulating factor (G-CSF), granulocyte-monocyte CSF, chemokine (C-X-C motif) ligand 1 (CXCL1), serum amyloid, IL-23) and several novel pyocyanin-responsive genes of potential importance in the infection process (IL-24, CXCL2, CXCL3, CCL20, CXCR4). This comprehensive study uncovers numerous details of pyocyanin's proinflammatory action and establishes airway epithelial cells as key responders to this microbial toxin.

Pulmonary inflammation in asthma is orchestrated by the activity of NF-kappaB. NO and NO synthase (NOS) activity are important modulators of inflammation. The availability of the NOS substrate, l-arginine, is one of the mechanisms that controls the activity of NOS. Arginase also uses l-arginine as its substrate, and arginase-1 expression is highly induced in a murine model of asthma. Because we have previously described that arginase affects NOx content and interferes with the activation of NF-kappaB in lung epithelial cells, the goal of this study was to investigate the impact of arginase inhibition on the bioavailability of NO and the implications for NF-kappaB activation and inflammation in a mouse model of allergic airway disease. Administration of the arginase inhibitor BEC (S-(2-boronoethyl)-l-cysteine) decreased arginase activity and caused alterations in NO homeostasis, which were reflected by increases in S-nitrosylated and nitrated proteins in the lungs from inflamed mice. In contrast to our expectations, BEC enhanced perivascular and peribronchiolar lung inflammation, mucus metaplasia, NF-kappaB DNA binding, and mRNA expression of the NF-kappaB-driven chemokine genes CCL20 and KC, and lead to further increases in airways hyperresponsiveness. These results suggest that inhibition of arginase activity enhanced a variety of parameters relevant to allergic airways disease, possibly by altering NO homeostasis.

In the course of Type 1 diabetes pro-inflammatory cytokines (e.g., IL-1β, IFN-γ and TNF-α) produced by islet-infiltrating immune cells modify expression of key gene networks in β-cells, leading to local inflammation and β-cell apoptosis. Most known cytokine-induced transcription factors have pro-apoptotic effects, and little is known regarding "protective" transcription factors. To this end, we presently evaluated the role of the transcription factor CCAAT/enhancer binding protein delta (C/EBPδ) on β-cell apoptosis and production of inflammatory mediators in the rat insulinoma INS-1E cells, in purified primary rat β-cells and in human islets. C/EBPδ is expressed and up-regulated in response to the cytokines IL-1β and IFN-γ in rat β-cells and human islets. Small interfering RNA-mediated C/EBPδ silencing exacerbated IL-1β+IFN-γ-induced caspase 9 and 3 cleavage and apoptosis in these cells. C/EBPδ deficiency increased the up-regulation of the transcription factor CHOP in response to cytokines, enhancing expression of the pro-apoptotic Bcl-2 family member BIM. Interfering with C/EBPδ and CHOP or C/EBPδ and BIM in double knockdown approaches abrogated the exacerbating effects of C/EBPδ deficiency on cytokine-induced β-cell apoptosis, while C/EBPδ overexpression inhibited BIM expression and partially protected β-cells against IL-1β+IFN-γ-induced apoptosis. Furthermore, C/EBPδ silencing boosted cytokine-induced production of the chemokines CXCL1, 9, 10 and CCL20 in β-cells by hampering IRF-1 up-regulation and increasing STAT1 activation in response to cytokines. These observations identify a novel function of C/EBPδ as a modulatory transcription factor that inhibits the pro-apoptotic and pro-inflammatory gene networks activated by cytokines in pancreatic β-cells.

The exact pathogenesis of plaque psoriasis remains to be fully determined, but it is thought to depend on environmental and genetic factors that stimulate dysregulated innate and adaptive immune responses in the skin. The cytokine interleukin (IL)-17A plays a key role in host defence against extracellular bacteria and fungi. An increasing body of evidence suggests that IL-17A is also important in psoriasis pathogenesis. While IL-17A is a key product of Th17 cells, it is also produced by neutrophils, mast cells and Tc17 cells. Each of these cell types is found in psoriatic lesions. IL-17A acts on keratinocytes to increase expression of chemokines (e.g. CCL20, CXCL1, CXCL3, CXCL5, CXCL6 and CXCL8) involved in recruiting myeloid dendritic cells, Th17 cells and neutrophils to the lesion site. IL-17A induces production of antimicrobial peptides and proinflammatory cytokines that, in turn, may help sustain immune responses in the skin. Blocking IL-17A improved psoriasis-like pathology in experimental models, and reductions in IL-17 signalling have been associated with response to tumour necrosis factor-α blockers in patients with psoriasis. Agents that inhibit IL-17 are in development and preliminary clinical results for IL-17 inhibitors indicate the importance of IL-17A in psoriasis pathophysiology. In a proof-of-concept and two phase II trials, three agents markedly reduced disease severity in patients with moderate-to-severe plaque psoriasis. One agent downregulated cytokines, chemokines and proteins associated with inflammatory responses in lesional skin. In summary, IL-17A is an attractive therapeutic target, which may allow selective intervention to address the dysregulated immune system in plaque psoriasis.

Liver metastases represent the major cause of death in patients with colorectal cancer (CRC). Recent studies have suggested that the chemotactic responses of tumor cells are necessary for metastatic spread to the liver, and CCL20 and CXCL8 have a strong association with CRC metastasis. The aim of our study was to identify the mechanisms by which CCL20 and CXCL8 synergize to promote metastatic progression and evaluated their potential as prognostic markers for CRC patients. The abilities of CCL20 and CXCL8 to promote CRC cell progression and epithelial-mesenchymal transition(EMT)phenotype were analyzed in vitro. Possible signaling pathways were investigated with specific pathway inhibitors and small interfering RNA (siRNA). 213 Patients with CRC who underwent surgery were enrolled for analysis of CCL20, CXCL8 and E-cadherin expressions in tumor tissues. Prognostic factors were then identified. CCL20 or CXCL8 alone was not sufficient to induce complete EMT in CRC cells, but both of them could coordinately induce EMT-like phenotype that was required to maintain CRC cell proliferation, migration and invasion. PI3K/AKT-ERK1/2 pathway crosstalk was demonstrated to be responsible for this process. Coexpression of CCL20 and CXCL8 was negatively correlated with E-cadherin expression in human CRC tissues. CRC patients with coexpression of CCL20 and CXCL8 were more likely to develop liver metastases and both coexpression was an independent high-risk factor for a most poor prognosis. CCL20 and CXCL8 synergize to promote CRC metastatic progression by coordinated induction of EMT via PI3K/AKT-ERK1/2 signaling axis. Detection of both coexpressions can be used to predict clinical outcomes in CRC patients.

BACKGROUND

The T helper 17 (Th17) cells recently identified as distinct T helper cell lineage are characterised by their production of the proinflammatory cytokine interleukin 17. Although much effort has been made in understanding the function of Th17 cells in the pathogenesis of different diseases, their influence in carcinogenesis remain largely unknown.

METHODS

We studied the prevalence and induction of Th17 cells in head and neck squamous cell carcinoma (HNSCC) patients by flow cytometry. To determine the migration mechanism of Th17 cells into primary tumours and metastasis of HNSCC, we performed chemotaxis assays. We analysed the proliferation and the angiogenesis-related proteins of HNSCCs in the presence of Th17 cells with MTT-based proliferation assay and an angiogenesis protein array.

RESULTS

In this study, we showed that the prevalence of Th17 cells is elevated in peripheral blood of HNSCC patients. In addition, tumour tissue and tumour-draining lymph nodes are infiltrated by a huge number of Th17 cells representing an important fraction of the tumour-infiltrating lymphocytes (TILs). We further showed that Th17 cells can be induced and expanded in tumour microenvironment through cytokines produced by tumour cells and TILs, and in addition can be recruited to the tumour milieu through a CCR6/CCL20-dependent mechanism. Furthermore, we showed that the proliferation and angiogenesis of HNSCC are impaired in the presence of Th17 cells.

CONCLUSIONS

We conclude that Th17 cells have a substantial impact on the carcinogenesis of HNSCCs and on their metastasis and could serve as a potential therapeutic target to modulate anti-tumour response in HNSCC.