IL-17 and IL-17F modulate GM-CSF production by lung microvascular endothelial cells stimulated with IL-1beta and/or TNF-alpha

Physiological roles of human interleukin-17 family

Interleukin-17 s (IL-17s) are well-known proinflammatory cytokines, and their antagonists perform excellently in the treatment of inflammatory skin diseases such as psoriasis. However, their physiological functions have not been given sufficient attention by clinicians. IL-17s can protect the host from extracellular pathogens, maintain epithelial integrity, regulate cognitive processes and modulate adipocyte activity through distinct mechanisms. Here, we present a systematic review concerning the physiological functions of IL-17s. Our goal is not to negate the therapeutic effect of IL-17 antagonists, but to ensure their safe use and reasonably explain the possible adverse events that may occur in their application.

Dual interleukin-17A/F deficiency protects against acute and chronic response to cigarette smoke exposure in mice

IL-17A and IL-17F are both involved in the pathogenesis of neutrophilic inflammation observed in COPD and severe asthma. To explore this, mice deficient in both Il17a and Il17f and wild type (WT) mice were exposed to cigarette smoke or environmental air for 5 to 28 days and changes in inflammatory cells in bronchoalveolar lavage (BAL) fluid were determined. We also measured the mRNA expression of keratinocyte derived chemokine (Kc), macrophage inflammatory protein-2 (Mip2), granulocyte–macrophage colony stimulating factor (Gmcsf) and matrix metalloproteinase-9 (Mmp9 ) in lung tissue after 8 days, and lung morphometric changes after 24 weeks of exposure to cigarette smoke compared to air-exposed control animals. Macrophage counts in BAL fluid initially peaked at day 8 and again on day 28, while neutrophil counts peaked between day 8 and 12 in WT mice. Mice dual deficient with Il17a and 1l17f showed similar kinetics with macrophages and neutrophils, but cell numbers at day 8 and mRNA expression of Kc, Gmcsf and Mmp9 were significantly reduced. Furthermore, airspaces in WT mice became larger after cigarette smoke exposure for 24 weeks, whereas this was not seen dual Il17a and 1l17f deficient mice. Combined Il17a and Il17f deficiency resulted in significant attenuation of neutrophilic inflammatory response and protection against structural lung changes after long term cigarette smoke exposure compared with WT mice. Dual IL-17A/F signalling plays an important role in pro-inflammatory responses associated with histological changes induced by cigarette smoke exposure.

Resveratrol Modulates Transforming Growth Factor-Beta (TGF-β) Signaling Pathway for Disease Therapy: A New Insight into Its Pharmacological Activities

Resveratrol (Res) is a well-known natural product that can exhibit important pharmacological activities such as antioxidant, anti-diabetes, anti-tumor, and anti-inflammatory. An evaluation of its therapeutic effects demonstrates that this naturally occurring bioactive compound can target different molecular pathways to exert its pharmacological actions. Transforming growth factor-beta (TGF-β) is an important molecular pathway that is capable of regulating different cellular mechanisms such as proliferation, migration, and angiogenesis. TGF-β has been reported to be involved in the development of disorders such as diabetes, cancer, inflammatory disorders, fibrosis, cardiovascular disorders, etc. In the present review, the relationship between Res and TGF-β has been investigated. It was noticed that Res can inhibit TGF-β to suppress the proliferation and migration of cancer cells. In addition, Res can improve fibrosis by reducing inflammation via promoting TGF-β down-regulation. Res has been reported to be also beneficial in the amelioration of diabetic complications via targeting the TGF-β signaling pathway. These topics are discussed in detail in this review to shed light on the protective effects of Res mediated via the modulation of TGF-β signaling.

Therapeutic Effects of Resveratrol in a Mouse Model of LPS and Cigarette Smoke-Induced COPD

This study was designed to examine whether resveratrol exerts the protective effects on LPS and cigarette smoke (LC)-induced COPD in a murine model. In lung histopathological studies, H&E, Masson's trichrome, and AB-PAS staining were performed. The cytokines (IL-6, IL-17, TGF-β, and TNF-α) and inflammatory cells in BALF were determined. The Beclin1 level in the lungs of mouse was analyzed. Compared with the LC-induced mouse, the level of inflammatory cytokines (IL-17, IL-6, TNF-α, and TGF-β) of the BALF in the resveratrol + cigarette smoke-treated mouse had obviously decreased. Histological examination of the lung tissue revealed that the resveratrol treatment attenuated the fibrotic response and mucus hypersecretion. In addition, resveratrol inhibited the expression of the Beclin1 protein in mouse lungs. The presented findings collectively suggest that resveratrol has a therapeutic effect on mouse LC-induced COPD, and its mechanism of action might be related to reducing the production of the Beclin1 protein.

Mechanisms of Cholera Toxin in the Modulation of TH17 Responses

Numerous studies have shown that TH17 cells and their signature cytokine IL-17A are critical to host defense against various bacterial and fungal infections. The protective responses mediated by TH17 cells and IL-17A include the recruitment of neutrophils, release of antimicrobial peptides and chemokines, and enhanced tight junction of epithelial cells. Due to the importance of TH17 cells in infections, efforts have been made to develop TH17-based vaccines. The goal of vaccination is to establish a protective immunological memory. Most currently approved vaccines are antibody-based and have limited protection against stereotypically different strains. Studies show that T-cell-based vaccines may overcome this limitation and protect hosts against infection of different strains. Two main strategies are used to develop TH17 vaccines: identification of TH17-specific antigens and TH17-skewing adjuvants. Studies have revealed that cholera toxin (CT) induces a potent Th17 response following vaccination. Antigen vaccination along with CT induces a robust TH17 response, which is sometimes accompanied by TH1 responses. Due to the toxicity of CT, it is hard to apply CT in a clinical setting. Thus, understanding how CT modulates TH17 responses may lead to the development of successful TH17-based vaccines.

Interleukin-17 potently increases non-small cell lung cancer growth

The aim of the present study was to explore the effects of interleukin (IL)-17 on the growth and metastasis of tumors that were subcutaneously implanted into C57BL/6 mice. Lewis lung carcinoma (LLC) cells were subcutaneously injected into C57BL/6 mice followed by intraperitoneal injection of mouse recombinant IL-17 protein (IL-17 groups) or phosphate-buffered saline (control groups). Tumor growth and metastasis were assessed by measuring the size and weight of tumors and cervical lymph nodes, respectively. Cytokine expression in tumor masses was quantified by reverse transcription-quantitative polymerase chain reaction and western blotting, respectively. CCR2-positive macrophage infiltration in tumor masses was detected by flow cytometric analysis. The proliferation and migration of LLC cells, stimulated by the IL-17 protein were detected by Cell Counting kit (CCK)-8 and wound scratch assays in vitro. Tumors were grafted into the C57BL/6 mice. The mice that were intraperitoneally injected with IL-17 exhibited significantly larger tumors compared with the control mice. After day 7 of injection and beyond, the weight of cervical lymph nodes in IL-17 groups was higher than that in the control mice. It was also demonstrated that the number of CCR2-positive macrophages that infiltrated the tumor masses in the IL-17 groups was higher than that of the control mice. CD34 expression in vascular endothelial cells was also higher in tumors grafted in IL-17 mice than those grafted in control mice. Furthermore, the tumor tissue mRNA and protein expression levels of vascular endothelial growth factor, matrix metalloproteinase (MMP)-2, MMP-9 and tumor necrosis factor-α were greater in mice from the IL-17 group than the control mice, while levels of migration inhibitory factor and thrombospondin-1 were lower in mice from the IL-17 group than in the control. IL-17 also increased the migration of LLC cells in vitro. In conclusion, IL-17 exhibited the ability to promote tumor growth by increasing angiogenesis, metastasis and increasing CCR2+ macrophage infiltration into tumors.

Expression of IL-17A and IL-17F in lipopolysaccharide-induced acute lung injury and the counteraction of anisodamine or methylprednisolone

Th17 cytokines IL-17A and IL-17F as pro-inflammatory cytokines played an important role in triggering inflammatory responses. However, little was known about the expression of IL-17A and IL-17F in acute lung injury (ALI). Therefore, the present study investigated the expression of IL-17A and IL-17F in lipopolysaccharide (LPS)-induced ALI in rats and rat pulmonary microvascular endothelial cells (PMVEC) by enzyme-linked immunosorbant assay or reverse transcription-polymerase chains reaction. Anisodamine and methylprednisolone were also investigated as anti-inflammatory strategy in the process of LPS-induced ALI. Lung injury was evaluated by histological changes, right lung wet weight:body weight (LW/BW) ratios, and protein education and total leukocyte count of bronchoalveolar lavage fluid (BALF). Our findings showed that LPS exposure elevated the levels of leukocyte number, protein education in BALF and the ratios of LW/BW, increased the expression of IL-17A and IL-17F in the lung tissues homogenate, BALF and serum of ALI rats. Up-regulation of IL-17F expression was also observed after LPS challenge in rat PMVEC. Treatment with anisodamine or methylprednisolone significantly inhibited the increases of parameters of ALI induced by LPS, and markedly reduced the expression of IL-17A and IL-17F in rats and the IL-17F expression in PMVEC. These data suggested that IL-17A and IL-17F maybe play an important role in LPS-induced ALI via autocrine and paracrine mechanisms, and anisodamine is similar in extent to methylprednisolone that contributes to relieve LPS-induced ALI.

IL-17A and Th17 cells in lung inflammation: an update on the role of Th17 cell differentiation and IL-17R signaling in host defense against infection

The significance of Th17 cells and interleukin- (IL-)17A signaling in host defense and disease development has been demonstrated in various infection and autoimmune models. Numerous studies have indicated that Th17 cells and its signature cytokine IL-17A are critical to the airway's immune response against various bacteria and fungal infection. Cytokines such as IL-23, which are involved in Th17 differentiation, play a critical role in controlling Klebsiella pneumonia (K. pneumonia) infection. IL-17A acts on nonimmune cells in infected tissues to strengthen innate immunity by inducing the expression of antimicrobial proteins, cytokines, and chemokines. Mice deficient in IL-17 receptor (IL-17R) expression are susceptible to infection by various pathogens. In this review, we summarize the recent advances in unraveling the mechanism behind Th17 cell differentiation, IL-17A/IL-17R signaling, and also the importance of IL-17A in pulmonary infection.

Interleukin-17A stimulates granulocyte-macrophage colony-stimulating factor release by murine osteoblasts in the presence of 1,25-dihydroxyvitamin D(3) and inhibits murine osteoclast development in vitro

OBJECTIVE

To investigate the effects of interleukin-17A (IL-17A) on osteoclastogenesis in vitro.

METHODS

Bone marrow cells (BMCs) were isolated from the excised tibia and femora of wild-type C57BL/6J mice, and osteoblasts were obtained by sequential digestion of the calvariae of ddY, C57BL/6J, and granulocyte-macrophage colony-stimulating factor-knockout (GM-CSF(-/-)) mice. Monocultures of BMCs or cocultures of BMCs and osteoblasts were supplemented with or without 1,25-dihydroxyvitamin D(3)(1,25[OH](2)D(3)), recombinant human macrophage colony-stimulating factor (M-CSF), RANKL, and IL-17A. After 5-6 days, the cultures were fixed with 4% paraformaldehyde and subsequently stained for the osteoclast marker enzyme tartrate-resistant acid phosphatase (TRAP). Osteoprotegerin (OPG) and GM-CSF expression were measured by enzyme-linked immunosorbent assay, and transcripts for RANK and RANKL were detected by real-time polymerase chain reaction.

RESULTS

In both culture systems, IL-17A alone did not affect the development of osteoclasts. However, the addition of IL-17A plus 1,25(OH)(2)D(3) to cocultures inhibited early osteoclast development within the first 3 days of culture and induced release of GM-CSF into the culture supernatants. Furthermore, in cocultures of GM-CSF(-/-) mouse osteoblasts and wild-type mouse BMCs, IL-17A did not affect osteoclast development, corroborating the role of GM-CSF as the mediator of the observed inhibition of osteoclastogenesis by IL-17A.

CONCLUSION

These findings suggest that IL-17A interferes with the differentiation of osteoclast precursors by inducing the release of GM-CSF from osteoblasts.

IL-17 level in patients with Dengue virus infection & its association with severity of illness

BACKGROUND

Clinical symptoms of Dengue vary from mild febrile illness to severe infection. A potent pro-inflammatory cytokine, IL-17, secreted by mainly Th17 cells mediate inflammation and autoimmune diseases. Role of IL-17 in pathogenesis of dengue virus (DV) infection is not clear.

METHODS

Total 211 dengue patients and 70 healthy controls were enrolled. IL-17 level was tested in serum samples from all cases and controls. Cases were grouped as either dengue or severe dengue; based on WHO (2009) classification. Anti DV IgG antibody detection and DV serotype specific PCR were also done. Levels of IL-17 in dengue and severe dengue patients, primary and secondary DV infection were compared. Association of DV serotypes with severity of illness and various clinical and laboratory features with IL-17 levels were analyzed.

RESULTS

Of total 211cases, 90 and 121cases were presenting as dengue and severe dengue illness, respectively. Levels of IL-17 were significantly higher in dengue patients as compared to control. Mean level of IL-17 was higher in severe cases than non severe cases; however difference was not statistically significant. Stratified analysis of IL-17 level in different age group showed significantly high IL-17 levels in children with severe dengue. Mean level of IL-17 was also significantly higher in cases with secondary DV infection in comparison to primary DV infection. Levels of IL-17 were higher in patients with DV-2 infection in comparison to cases with DV-1 and DV-3 infection. Significant positive association of high IL-17 levels was seen with pleural effusion and respiratory distress.

CONCLUSION

IL-17 appears to be associated with severe DV infection. It is very important to understand the exact role of IL-17 in the pathogenesis of severe DV infection.

IL-17A stimulates granulocyte colony-stimulating factor production via ERK1/2 but not p38 or JNK in human renal proximal tubular epithelial cells

We investigated the potential role of IL-17A in the induction of granulocyte colony-stimulating factor (G-CSF), a critical granulopoietic growth factor, in human renal proximal tubular epithelial cells. Human renal proximal tubular cells (HK-2, ATCC) were used to characterize the effects of IL-17A or IL-17F on G-CSF production, using ELISA, real-time RT-PCR, and immunoblotting. The cell surface expression of IL-17 receptors (IL-17Rs) was analyzed by flow cytometry. IL-17A stimulation of proximal tubular cells led to a dose- and time-dependent increase in secreted G-CSF. This effect was dependent on mRNA transcription and protein translation. Real-time RT-PCR demonstrated that G-CSF mRNA expression reached a maximum level at 6 h following IL-17A stimulation and that this increase was dose dependent. Both IL-17RA and IL-17RC were expressed on proximal tubular cells. IL-17A also enhanced TNF-α- or IL-1β-mediated G-CSF secretion from cells. Additionally, IL-17A induced MAPK (ERK1/2 but not p38 MAPK or JNK) activation, and pharmacological inhibitors of MEK1/2 (U0126) but not of p38 MAPK (SB203580) or JNK (SP600125), significantly blocked the IL-17A-mediated G-CSF release. We demonstrated the potential ability of IL-17A to induce G-CSF in renal proximal tubular cells. It is proposed that IL-17A may play an important role in neutrophil transmigration and activation via stimulation of G-CSF in tubular injury.

IL-17A and IL-17F stimulate chemokines via MAPK pathways (ERK1/2 and p38 but not JNK) in mouse cultured mesangial cells: synergy with TNF-α and IL-1β

We investigated the role of IL-17 family members IL-17A and IL-17F in the induction of chemokines in mouse cultured mesangial cells (SV40 MES 13 cells). We evaluated the expression of the chemokines monocyte chemoattractant protein-1 (MCP-1) and macrophage inflammatory protein-2 (MIP-2) by ELISA and real-time RT-PCR (Q-PCR). Activation of MAPK was assessed by immunoblotting. IL-17RA and IL-17RC were inhibited by small interfering RNA (siRNA). We found that IL-17A or IL-17F stimulation of mesangial cells led to both a dose- and time-dependent increase in MCP-1 and MIP-2 release. This effect was dependent on mRNA transcription and protein translation. Both also enhanced TNF-α- and IL-1β-mediated MCP-1 and MIP-2 release in the cells. Additionally, we observed that IL-17A and IL-17F induced MAPK (p38 MAPK, ERK1/2, and JNK) activation and that pharmacological inhibitors of p38 MAPK (SB203580) and ERK1/2 (U0126), but not JNK (SP600125), blocked the IL-17A/IL-17F-mediated MCP-1 and MIP-2 release. Mesangial cells expressed IL-17RA and IL-17RC, and the IL-17A-mediated MCP-1 and MIP-2 release was significantly blocked by soluble IL-17RA. Furthermore, inhibition of either IL-17RA or IL-17RC expression via siRNA led to significant reduction of IL-17A/IL-17F-stimulated chemokine production. We conclude that IL-17A and IL-17F induce the production of chemokines MCP-1 and MIP-2 via MAPK pathways (p38 MAPK and ERK1/2), as well as mRNA transcription and protein translation and have synergistic effects with TNF-α and IL-1β in cultured mesangial cells.

Differentiation and function of pro-inflammatory Th17 cells

After activation, CD4+ helper T (Th) cells differentiate into cytokine-secreting effector subsets. A novel subset of CD4+ helper T (Th) cells that produce two related cytokines IL-17 and IL-17F has been recently identified and shown to play critical function in inflammation and autoimmunity. Here I summarize recent work by us as well as other investigators in understanding the transcriptional regulation of Th17-cell differentiation, their developmental relationship with regulatory T cells and the function of IL-17 and IL-17F in vivo.

The roles of IL-17A in inflammatory immune responses and host defense against pathogens

T-helper 17 (Th17) cells are a newly discovered CD4(+) helper T-cell subset that produces interleukin-17A (IL-17A) and IL-17F. IL-17A plays important roles in allergic responses such as delayed-type hypersensitivity, contact hypersensitivity, and allergic airway inflammation. IL-17A promotes inflammation by inducing various proinflammatory cytokines and chemokines, recruiting neutrophils, enhancing antibody production, and activating T cells. IL-17A expression is also augmented in autoimmune diseases such as multiple sclerosis and rheumatoid arthritis. Using mouse models of these diseases, we found that IL-17A plays a central role in their development. IL-6 is required for the development of Th17 cells and tumor necrosis factor functions downstream of IL-17A during the effector phase. IL-1 is important both for developing Th17 cells and eliciting inflammation. Th17 cells, like Th1 and Th2 cells, are involved in host defense against infections, but the contribution of these Th subsets to defense mechanisms differs among pathogens. The roles of IL-17F remain largely unknown. In this review, we introduce how IL-17A/IL-17F are involved in inflammatory immune responses and host defense mechanisms and discuss their relationship with other cytokines in the development of inflammatory and infectious diseases.

Regulation and pro-inflammatory function of interleukin-17 family cytokines

The interleukin-17 (IL-17) family consists of six cytokines in mammals. Among them, IL-17 and IL-17F are expressed by a novel subset of CD4(+) helper T cells and play critical function in inflammation and autoimmunity. IL-17E, also called IL-25, has been associated with allergic responses. Here, I summarize recent work by my laboratory as well as other investigators in understanding the regulation and function of these three cytokines. From these studies, IL-17 family cytokines may serve as novel targets for pharmaceutical intervention of immune and inflammatory diseases.

Interleukin-17F-induced pulmonary microvascular endothelial monolayer hyperpermeability via the protein kinase C pathway

BACKGROUND

Interleukin (IL)-17F is involved in lung inflammation, but the effect of IL-17F on endothelial permeability and its signaling pathway remain ill-defined. The current study sought to investigate the effect of IL-17F on endothelium and assess the role of protein kinase C (PKC) and src-suppressed C kinase substrate (SSeCKS) in this process.

METHODS

Rat pulmonary microvascular endothelial monolayers were constructed to determine changes of permeability as measured by means of FITC-dextran and Hank's solution flux across monolayers and transendothelial electrical resistance with or without IL-17F and PKC inhibitors. Additional monolayers were stained using FITC-phalloidin for filamentous actin (F-actin). The gene expression of SSeCKS was analyzed by the reverse transcription-polymerase chains. Alterations of SSeCKS protein were investigated by immunoblotting and immunoprecipitation.

RESULTS

IL-17F increased endothelial monolayer permeability in a dose- and time-dependent manner. F-actin staining revealed that permeability changes were accompanied by reorganization of cytoskeleton. In the presence of PKC inhibitors, the IL-17F-induced hyperpermeability and reorganization of F-actin were attenuated. The gene and protein expression of SSeCKS were conspicuously elevated after IL-17F challenge. The process of SSeCKS phosphorylation followed a time course that mirrored the time course of hyperpermeability induced by IL-17F. IL-17F-induced SSeCKS phosphorylation was abrogated after PKC inhibitors pretreatment. The translocation of SSeCKS from the cytosol to the membrane and a significant increase in the SSeCKS association with the cytoskeleton were found after IL-17F treatment.

CONCLUSIONS

IL-17F is an important mediator of increased endothelial permeability. PKC and SSeCKS are integral signaling components essential for IL-17F-induced hyperpermeability.

Role of the novel Th17 cytokine IL-17F in inflammatory bowel disease (IBD): upregulated colonic IL-17F expression in active Crohn's disease and analysis of the IL17F p.His161Arg polymorphism in IBD

BACKGROUND

Interleukin (IL)-17F, produced in IL-23R-expressing Th17 cells, is a novel member of the IL-17 cytokine family. Given the association of IL23R with inflammatory bowel disease (IBD), we characterized the role of IL-17F in IBD including its intestinal gene expression and the effect of the IL17F p.His161Arg polymorphism on disease susceptibility and phenotype of Crohn's disease (CD) and ulcerative colitis (UC). In addition, we analyzed the IL17F p.His161Arg polymorphism for potential epistasis with IL23R and NOD2/CARD15 variants.

METHODS

Intestinal IL-17F mRNA expression was measured by quantitative polymerase chain reaction (PCR). Genomic DNA from 1682 individuals (CD: n = 499; UC: n = 216; controls: n = 967) was analyzed for the presence of the IL17F p.His161Arg polymorphism, the 3 NOD2 variants, p.Arg702Trp, p.Gly908Arg, and p.Leu1007fsX1008, and 10 CD-associated IL23R variants.

RESULTS

Intestinal IL-17F mRNA expression was 4.4-fold increased in inflamed colonic lesions compared to uninflamed biopsies in CD (P = 0.016) but not in UC. However, the mean intestinal IL-17F mRNA expression was higher in UC than in CD (P < 0.0001). The IL17F p.His161Arg substitution was observed with similar frequencies in IBD patients and controls and was not associated with a certain disease phenotype, but weakly associated with a low body mass index (BMI; P = 0.009) and an earlier age of disease onset (P = 0.039) in UC. There was no evidence for epistasis between the IL17F p.His161Arg polymorphism and IBD-associated single nucleotide polymorphisms within the IL23R gene.

CONCLUSIONS

Intestinal IL17F gene expression is increased in active CD. The IL17F p.His161Arg polymorphism is not associated with IBD susceptibility and has no epistatic interaction with CD-associated IL23R variants.

Regulatory mechanisms of helper T cell differentiation: new lessons learned from interleukin 17 family cytokines

Interleukin 17 (IL-17) family consists of six cytokines in mammals. Among them, IL-17 and IL-17F are expressed by a novel subset of CD4+ helper T (Th) cells and play critical function in inflammation and autoimmunity. On the other hand, IL-17E, also called IL-25, has been associated with allergic responses. Here we summarize recent work by us as well as other investigators in understanding the regulation and function of these three cytokines. From these studies, IL-17 family cytokines may serve as novel targets for pharmaceutical intervention of immune and inflammatory diseases.

Interleukin-17A modulates human airway epithelial responses to human rhinovirus infection

Human rhinovirus (HRV) infections are associated with exacerbations of asthma and chronic obstructive pulmonary disease that are characterized by a selective neutrophil infiltration. IL-17A, a cytokine derived primarily from activated T cells, has been linked to neutrophilic inflammation of the airways. We hypothesized that IL-17A alters the response of HRV-infected epithelial cells to modulate airway inflammatory cell populations. IL-17A synergistically enhanced HRV-16-induced epithelial production of the neutrophil chemoattractant, IL-8, as well as human beta-defensin-2 (HBD-2), a chemoattractant for immature dendritic cells and memory T cells, but suppressed viral production of the eosinophil chemoattractant, RANTES. These effects were not due to alterations of viral uptake or replication by IL-17A. The synergy between HRV-16 and IL-17A for IL-8 protein production was both dose- and time-dependent. IL-8 induction by IL-17A or HRV-16, alone and in combination, was reduced by inhibitors of the p38 and p44/42 MAPK pathways. By contrast, induction of HBD-2 depended on the activation of the p38 and JNK pathways. The ability of IL-17A to synergistically enhance HRV-induced IL-8 is mediated posttranscriptionally, since IL-8 promoter activation by the combination of the two stimuli was merely additive, whereas the combination of IL-17A and HRV-16 led to stabilization of IL-8 mRNA. Similarly, stimulation of HBD-2 promoter constructs by the combination of IL-17A and HRV-16 was no more than the sum of the individual responses. Further studies are needed to examine HBD-2 mRNA stability. Taken together, these data represent the first demonstration that IL-17A can modify epithelial responses to HRV in a manner that would be expected to favor the recruitment of neutrophils, immature dendritic cells, and memory T cells to the airways.

The Effect of Interleukin-17 on the Proliferation and Invasion of JEG-3 Human Choriocarcinoma Cells

PROBLEM

As there has been a study in mice showing the expression of IL-17 by decidual cells and the status of IL-17 receptor expression in human pregnancy is not known, we hypothesized that IL-17 may regulate human trophoblast proliferation and invasion.

METHOD OF STUDY

JEG-3 cell line was used as a model for human trophoblast. Immunohistochemitry and reverse transcriptase polymerase chain reaction techniques were used to identify IL-17 receptor protein and mRNA, respectively. The effects of IL-17 on JEG-3 cell proliferation and invasion were tested using the BrdU incorporation and the Matrigel invasion assays, respectively.

RESULTS

IL-17 increased the invasive capacity of JEG-3 cells but had no effect on the proliferation and multinucleated formation of JEG-3 cells.

CONCLUSION

In this JEG-3 cell model of human trophoblast, the IL-17R and IL-17 may have a regulatory role in trophoblast invasion.

IL-17 enhances the net angiogenic activity and in vivo growth of human non-small cell lung cancer in SCID mice through promoting CXCR-2-dependent angiogenesis

In this study, we examined the biological action of IL-17 on human non-small cell lung cancer (NSCLC). Although IL-17 had no direct effect on the in vitro growth rate of NSCLC, IL-17 selectively augmented the secretion of an array of angiogenic CXC chemokines, including CXCL1, CXCL5, CXCL6, and CXCL8 but not angiostatic chemokines, by three different NSCLC lines. Endothelial cell chemotactic activity (as a measure of net angiogenic potential) was increased in response to conditioned medium from NSCLC stimulated with IL-17 compared with those from unstimulated NSCLC. Enhanced chemotactic activity was suppressed by neutralizing mAb(s) to CXCL1, CXCL5, and CXCL8 or to CXCR-2 but not to vascular endothelial growth factor-A. Transfection with IL-17 into NSCLC had no effect on the in vitro growth, whereas IL-17 transfectants grew more rapidly compared with controls when transplanted in SCID mice. This IL-17-elicited enhancement of NSCLC growth was associated with increased tumor vascularity. Moreover, treatment with anti-mouse CXCR-2-neutralizing Ab significantly attenuated the growth of both neomycin phosphotransferase gene-transfected and IL-17-transfected NSCLC tumors in SCID mice. A potential role for IL-17 in modulation of the human NSCLC phenotype was supported by the findings that, in primary NSCLC tissues, IL-17 expression was frequently detected in accumulating and infiltrating inflammatory cells and that high levels of IL-17 expression were associated with increased tumor vascularity. These results demonstrate that IL-17 increases the net angiogenic activity and in vivo growth of NSCLC via promoting CXCR-2-dependent angiogenesis and suggest that targeting CXCR-2 signaling may be a novel promising strategy to treat patients with NSCLC.