Recombinant interleukin-17A Research Articles

Beclomethasone dipropionate and formoterol reduce oxidative/nitrosative stress generated by cigarette smoke extracts and IL-17A in human bronchial epithelial cells

Interleukin-17A (IL-17A), cigarette smoke and oxidative/nitrosative stress are involved in inflammatory airway diseases, and the mechanisms behind these processes are still poorly understood. We investigated whether recombinant human IL-17A (rhIL-17A), in combination with cigarette smoke extracts (CSE), increases the levels of inducibile nitric oxide synthase (iNOS), reactive oxygen species, nitrotyrosine (NT) and the activation of signal transducer and activator of transcription 1 (STAT-1) in normal human bronchial epithelial cells (16HBE). The effect of beclomethasone dipropionate (BDP), formoterol and their combination was also evaluated. We demonstrated that rhIL-17A or CSE alone increases iNOS expression, reactive oxygen species and NT production and STAT-1 downstream signalling activation in terms of STAT-1ser727 and STAT-1tyr701 phosphorylation. The combination of both stimuli further increased iNOS, ROS, NT and STAT-1ser727 phosphorylation. The silencing of STAT-1 expression partially reduced the levels of iNOS, reactive oxygen species and NT generated by rhIL-17A and inhibited the effect of CSE alone in 16HBE cells. The treatment of the cells with the MEK1/2 inhibitor U0126 (1,4-diamino-2,3-dicyano-1,4-bis (o-aminophenylmercapto butadiene) abolished the expression of iNOS and STAT-1ser727 phosphorylation generated by rhIL-17A. 16HBE treated with BDP or formoterol alone partially suppressed the effect of IL-17A or CSE on ROS, NT, and STAT-1 activation. Furthermore the use of the drugs in combination showed an additive effect in 16HBE. Our findings demonstrate that IL-17A increases oxidative/nitrosative markers, likely via ERK1/2 downstream signalling and STAT-1 pathway activation in human bronchial epithelial cells. BDP and formoterol treatment reduces this effect showing an additive effect used in combination.

Molecular Cloning, Expression, and In Silico Structural Analysis of Guinea Pig IL-17

Interleukin-17A (IL-17A) is a potent proinflammatory cytokine and the signature cytokine of Th17 cells, a subset which is involved in cytokine and chemokine production, neutrophil recruitment, promotion of T cell priming, and antibody production. IL-17 may play an important role in tuberculosis and other infectious diseases. In preparation for investigating its role in the highly relevant guinea pig model of pulmonary tuberculosis, we cloned guinea pig IL-17A for the first time. The complete coding sequence of the guinea pig IL-17A gene (477 nucleotides; 159 amino acids) was subcloned into a prokaryotic expression vector (pET-30a) resulting in the expression of a 17kDa recombinant guinea pig IL-17A protein which was confirmed by mass spectrometry analysis. Homology modeling of guinea pig IL-17A revealed that the three-dimensional structure resembles that of human IL-17A. The secondary structure predicted for this protein showed the presence of one extra helix in the N-terminal region. The expression profile of IL-17A was analyzed quantitatively in spleen, lymph node, and lung cells from BCG-vaccinated guinea pigs by real-time PCR. The guinea pig IL-17A cDNA and its recombinant protein will serve as valuable tools for molecular and immunological studies in the guinea pig model of pulmonary TB and other human diseases.

Optimising the quantification of cytokines present at low concentrations in small human mucosal tissue samples using Luminex assays

Sensitive measurement of multiple cytokine profiles from small mucosal tissue biopsies, for example human gastric biopsies obtained through an endoscope, is technically challenging. Multiplex methods such as Luminex assays offer an attractive solution but standard protocols are not available for tissue samples. We assessed the utility of three commercial Luminex kits (VersaMAP, Bio-Plex and MILLIPLEX) to measure interleukin-17A (IL-17) and interferon-gamma (IFNγ) concentrations in human gastric biopsies and we optimised preparation of mucosal samples for this application. First, we assessed the technical performance, limits of sensitivity and linear dynamic ranges for each kit. Next we spiked human gastric biopsies with recombinant IL-17 and IFNγ at a range of concentrations (1.5 to 1000pg/mL) and assessed kit accuracy for spiked cytokine recovery and intra-assay precision. We also evaluated the impact of different tissue processing methods and extraction buffers on our results. Finally we assessed recovery of endogenous cytokines in unspiked samples. In terms of sensitivity, all of the kits performed well within the manufacturers' recommended standard curve ranges but the MILLIPLEX kit provided most consistent sensitivity for low cytokine concentrations. In the spiking experiments, the MILLIPLEX kit performed most consistently over the widest range of concentrations. For tissue processing, manual disruption provided significantly improved cytokine recovery over automated methods. Our selected kit and optimised protocol were further validated by measurement of relative cytokine levels in inflamed and uninflamed gastric mucosa using Luminex and real-time polymerase chain reaction. In summary, with proper optimisation Luminex kits (and for IL-17 and IFNγ the MILLIPLEX kit in particular) can be used for the sensitive detection of cytokines in mucosal biopsies. Our results should help other researchers seeking to quantify multiple low concentration cytokines in small tissue samples.

Interleukin‐17A stimulates granulocyte–macrophage colony‐stimulating factor release by murine osteoblasts in the presence of 1,25‐dihydroxyvitamin D3 and inhibits murine osteoclast development in vitro

To investigate the effects of interleukin-17A (IL-17A) on osteoclastogenesis in vitro. 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. 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. These findings suggest that IL-17A interferes with the differentiation of osteoclast precursors by inducing the release of GM-CSF from osteoblasts.

Unexpected mucin-type O-glycosylation and host-specific N-glycosylation of human recombinant interleukin-17A expressed in a human kidney cell line

The T helper cell-derived cytokine interleukin-17A (IL-17A) is a variably glycosylated disulfide-linked homodimer of 34–38kDa. Its polypeptide monomer contains one canonical N-glycosylation site at Asn68, and human recombinant IL-17A was partly N-glycosylated when expressed in human kidney (HEK293) cells as a fusion protein with a melittin signal sequence and an N-terminal hexahistidine tag. Orbitrap mass analyses of the tryptic N-glycopeptide 63–69 indicated that the N-glycosylation was of the GalNAc-terminated type characteristic of cultured kidney cells. The mass spectrum of IL-17A monomer also included peaks shifted by +948Da from the respective masses of unglycosylated and N-glycosylated polypeptides. These were caused by unpredicted partial O-glycosylation of Thr26 with the mucin-like structure -GalNAc(-NeuNAc)-Gal-NeuNAc. Identical O-glycosylation occurred in commercially sourced recombinant IL-17A also expressed in HEK293 cells but with a different N-terminal sequence. Therefore, the kidney host cell line not only imposed its characteristic pattern of N-glycosylation on recombinant IL-17A but additionally created an O-glycosylation not known to be present in the T cell-derived cytokine. Mammalian host cell lines for recombinant protein expression generally impose their characteristic patterns of N-glycosylation on the product, but this work exemplifies how a host may also unpredictably O-glycosylate a protein that is probably not normally O-glycosylated.

The effects of rIL-17A intranasal inoculation against Streptococcus pneumoniae infection in murine models

Objective To evaluate the effects of intranasal administration of recombinant interleukin-17A(rIL-17A) on the expressions of β-Defensin-2(Defb2) and macrophage inflammatory protein(MIP) in pneumococcal pneumonia murine models.Methods Twenty-four BALB/c mice were divided randomly into normal control,pneumococcal pneumonia,and rIL-17A intervention groups ( n =8 ).Before intranasal (i.n) infection with Streptococcus pneumoniae,the mouse was treated with PBS or rIL-17Ai.n respectively.The mRNA levels of Defb2,MIP-1α and MIP-2β expression in lung tissue were detected by real-time quantity PCR.The numbers of bacteria and leukocytes in bronchoalveolar lavage fluid (BALF) were counted as well.And the concentrations of MIP-1α,MIP-2β,IFN-γ and IL-4 in BALF and in supematants of spleen cells and mediastinal lymph node cells were assayed by ELISA.Changes in lung tissue histopathology were observed with HE staining through light microscope.Results Neutrophil and macrophage numbers are higher in BALF of rIL-17A group,while the numbers of bacteria were lower,when compared with those in pneumonia group( P＜0.01 ).The expression of Defb2 and MIP-1α mRNA were up-regulated in lung after rIL17A treatment(P＜0.01 ).When compared with rIL-17A non-treated mice,rIL-17A treated mice secretedhigher levels of MIP-1α in lymph node cell culture supernatants( P＜0.01 ),higher levels of MIP-2β were observed in spleen cell and lymph node cell culture supernatants( P＜0.01 ),higher levels of IFN-T were detected in BALF( P ＜ 0.01 ) and culture supernatants of spleen cell ( P ＜ 0.01 ) and lymph node cell ( P ＜0.05),and higher levels of IL-4 were detected in BALF and spleen cell culture supernatant(P＜0.01 ).Comparative analysis have not detect a significant irflammatory cell increases in rIL-17A treated mice lung tissue; however the histopathological lesions were decreased.Conclusion Intranasal inoculation of rIL-17A can promote pulmonary neutrophil and macrophage recruitment and bacterium clearance,Intranasal inoculation of riL-17enhances the host defense against Streptococcus pneumoniae infection partly through increasing the expression levels of defensins,MIP,IFN-T and IL-4 etc. Key words: Streptococcus pneumoniae; Interleukin-17A; Macrophage inflammatory protein; Chemotactic factor

Staphylococcal-associated molecular patterns enhance expression of immune defense genes induced by IL-17 in mammary epithelial cells

Interleukin-17A (IL-17A) and IL-17F have been shown to mediate a crucial crosstalk between the immune system and various epithelial tissues, stimulating various defensive mechanisms to bacterial infections. A number of studies have characterized the response to IL-17A and IL-17F of epithelial cells from airways, intestine, and skin, but not from the mammary gland. To evaluate the potential contribution of IL-17 to the immune defense of the mammary gland, we analyzed the effects of recombinant bovine IL-17A and IL-17F on primary bovine mammary epithelial cells (MEC) by quantitative PCR and ELISA. We found expression (mRNA) of the two components of the IL-17 receptor complex, IL-17RA and IL-17RC, in mammary tissue and MEC in vitro. The expression of a number of genes encoding cytokines, chemokines and proteins endowed with antibacterial activities was increased by IL-17A, and to a lesser extent by IL-17F, but the magnitude of responses was modest. As expected, responses were augmented by the combination of IL-17A or IL-17F with TNF-α. Interestingly, responses of a few of the tested genes, such as IL8, CCL20, iNOS, and CfB, were augmented by the combination of IL-17A with staphylococcal lipoteichoic acid or muramyl dipeptide, bacterial agonists of the innate immune system. This can be interpreted as indicating that IL-17A and IL-17F are tailored to exert their full potential in a septic environment. MEC responses were characterized by the expression of chemokines targeting not only neutrophils (CXCL3 and CXCL8) but also mononuclear leucocytes (CCL2, CCL20). Production of IL-6 was low and the inflammatory cytokines TNF-α and IL-1β were expressed (mRNA) but proteins were not secreted. Altogether, our results suggest that IL-17A and IL-17F have a potential to modulate the mammary gland immune response to mastitis-causing pathogens.

Interleukin-17A is involved in development of spontaneous pulmonary emphysema caused by Toll-like receptor 4 mutation

To explore the pathogenic role of Th17 cells and interleukin-17A (IL-17A)-associated signaling pathways in spontaneous pulmonary emphysema induced by a Toll-like receptor 4 mutant (TLR4(mut)). Lungs were obtained from wild-type (WT) or TLR4mut mice that were treated with or without recombinant mouse IL-17A (1 μg·kg(-1)·d(-1), ip) from the age of 3 weeks to 3 months. Pulmonary emphysema was determined using histology, immunochemistry, and biochemical analysis. T cell polarization was determined with flow cytometry, the levels of cytokines were measured using ELISA, and the levels of IL-17A-associated signaling molecules were detected using Western blot. Compared to WT mice, 3 month-old TLR4(mut) mice were characterized by significantly reduced infiltration of Th17 cells into lungs (2.49%±1.13 % νs 5.26%±1.39%), and significantly reduced expression levels of IL-17A (3.66±0.99 pg/μg νs 10.67±1.65 pg/μg), IL-23 (12.43±1.28 pg/μg νs 28.71±2.57 pg/μg) and IL-6 (51.82±5.45 pg/μg νs 92.73±10.91 pg/μg) in bronchoalveolar lavage fluid. In addition, p38 MAPK phosphorylation and AP-1 expression were decreased to 27%±9% and 51%±8%, respectively, of that in WT mice. Treatment of TLR4(mut) mice with IL-17A increased the infiltration of Th17 cells into lungs and expression levels of IL-17A, IL-6, and IL-23 in bronchoalveolar lavage fluid, attenuated MDA and apoptosis, and improved emphysema accompanied with increased phosphorylation of p38 MAPK and expression of AP-1. Th17 cells, in particular the cytokine IL-17A, play a crucial role in the pathogenesis of TLR4(mut)-induced spontaneous pulmonary emphysema. Both of them are potential targets for therapeutic strategies for pulmonary emphysema.

Prokaryotic expression of mouse interleukin 17A and its ability of stimulating RAW264.7 cell inflammatory factors expression

Objective To express and purify mouse interleukin 17A(mIL-17A) in E. coli and to analyze its ability of stimulating macrophage inflammatory factors expression. Methods The coding gene of mouse mIL-17A mature protein was amplified from mouse spleen cells by RT-PCR. PCR product was cloned into the prokaryotic expressing vector pET28a, and the resulting recombinant plasmid pET28a/mIL-17a was then transformed into the host E. coli strain BL21(DE3) for expression. The mIL-17A protein was identified by SDS-PAGE and Western blot. The recombinant protein was purified by the Ni-NTA affinity chromatography, and was further tested on the stimulation of cytokine and chemokine of RAW264.7 cells by ELISA and real-time quantity PCR in vitro. Results The mIL-17A with bioactivity was over-expressed and purified successfully, and the results of real-time PCR and ELISA showed that recombinant mIL-17A stimulated macrophage mRNA upregulation of IL-6, defensin β2 and Cxcl3 and secretion of defensin β2, Ccl3, Cxcl3,IFN-γ, IL-6 and IL-4. Interestingly, these effects could be blocked by the addition of anti-IL-17A neutralizing antibody partly. After treatment with mIL-17, 74. 87-fold of defensin β2 mRNA expression was increased comparing with that of untreated cells( P ＜0.01 ), while blocking with anti-IL-17A antibody the increase was only 5.4-fold(P ＜ 0.01 ). Conclusion The recombinant mIL-17A has a strong stimulation on secretion of cytokine and chemokine of macrophage, that maybe result to the enhancement of anti-infection ability of macrophage. Key words: Recombinant interleukin 17A; Macrophage inflammatory protein; Anti-infection immunity; Beta-defensin

Expression, refolding and purification of a human interleukin-17A variant

A human interleukin-17A (IL-17A) variant was overexpressed in Escherichia coli BL21 (DE3) under the control of a T7 promoter. The resulting insoluble inclusion bodies were isolated and solubilized by homogenization with 6M guanidine HCl. The denatured recombinant human IL-17A variant was refolded in 20mM Tris–HCl, pH 9.0, 500mM arginine, 500mM guanidine HCl, 15% glycerol, 1mM cystamine, and 5mM cysteine at 2–8°C for 40h. The refolded IL-17A variant was subsequently purified using a combination of cation-exchange, reversed-phase and fluoroapatite chromatography. The final purified product was a monodisperse and crystallizable homodimer with a molecular weight of 30,348.3Da. The protein was active in both receptor binding competition assay and IL-17A-dependent biological activity assay using human dermal fibroblasts.

Abstract 1436: Interleukin-17A stimulates expression of chemokines and cytokines in prostatic epithelial cells via nuclear factor-kappaB and extracellular signal-regulated kinase pathways

Abstract T helper 17 (Th17) cells secret interleukin-17A (IL-17A) and interleukin-17F. Th17 cells and IL-17A are increased in prostate tumors. The role of IL-17A in prostate cancer is not clear. The objective of this in-vitro study was to investigate the effects of IL-17A on prostatic epithelial cells. Cell growth assay, Western blot, and real-time quantitative reverse transcription- polymerase chain reaction (qRT-PCR) analysis were used to measure the effects of IL-17A on the immortalized normal human prostatic epithelial cell lines (RWPE-1 and pRNS-1-1), human high-grade prostatic intraepithelial neoplasia (PIN) cell line, human prostate cancer LNCaP cell line, and mouse prostate cancer TRAMP-C1 cell line. We found that recombinant human IL-17A (20 ng/ml) did not affect cell growth rate in any of the prostatic cell lines studied. IL-17A did not significantly activate Nuclear Factor-kappaB (NF-kappaB) or Extracellular signal-Regulated Kinase (ERK) signaling pathway in RWPE-1, pRNS-1-1, or PIN cells. IL-17A activated NF-kappaB and/or ERK signaling pathways in LNCaP and TRAMP-C1 cells. When IL-17RC (receptor of IL-17A) was overexpressed in PIN and LNCaP cells, activation of NF-kappaB or ERK signaling pathway by IL-17A was significantly enhanced. IL-17A modestly induced mRNA expression of chemokines (CXCL1 and CXCL2) in RWPE-1, pRNS-1-1, and PIN cells. IL-17A induced mRNA expression of chemokines (CXCL1, CXCL2, CCL2, CCL5, CCL7, and CCL20) and cytokine IL-6 in LNCaP cells. In mouse TRAMP-C1 cells, IL-17A induced mRNA expression of chemokines (CXCL1, CXCL2, CXCL5, CCL2, and CCL5) and cytokine IL-6. When IL-17RC was overexpressed in PIN and LNCaP cells, chemokine expression was significantly enhanced. Our findings suggest that although IL-17A has no effects on cell growth in-vitro, it may modulate the stroma-epithelial interaction in tumor microenvironment in-vivo via stimulation of expression of chemokines and cytokines. Acknowledgement: DoD W81XWH-05-1-0567, NIH/NCRR 2P20 RR020152-06, and LCRC Fund. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 1436.