interleukin-17C Research Articles

IL-17C-mediated innate inflammation decreases the response to PD-1 blockade in a model of Kras-driven lung cancer

Chronic obstructive pulmonary disease (COPD) is associated with neutrophilic lung inflammation and CD8 T cell exhaustion and is an important risk factor for the development of non-small cell lung cancer (NSCLC). The clinical response to programmed cell death-1 (PD-1) blockade in NSCLC patients is variable and likely affected by a coexisting COPD. The pro-inflammatory cytokine interleukin-17C (IL-17C) promotes lung inflammation and is present in human lung tumors. Here, we used a Kras-driven lung cancer model to examine the function of IL-17C in inflammation-promoted tumor growth. Genetic ablation of Il-17c resulted in a decreased recruitment of inflammatory cells into the tumor microenvironment, a decreased expression of tumor-promoting cytokines (e.g. interleukin-6 (IL-6)), and a reduced tumor proliferation in the presence of Haemophilus influenzae- (NTHi) induced COPD-like lung inflammation. Chronic COPD-like inflammation was associated with the expression of PD-1 in CD8 lymphocytes and the membrane expression of the programmed death ligand (PD-L1) independent of IL-17C. Tumor growth was decreased in Il-17c deficient mice but not in wildtype mice after anti-PD-1 treatment. Our results suggest that strategies targeting innate immune mechanisms, such as blocking of IL-17C, may improve the response to anti-PD-1 treatment in lung cancer patients.

Comparative study of interleukin-17C (IL-17C) and IL-17D in large yellow croaker Larimichthys crocea reveals their similar but differential functional activity

Interleukin 17 (IL-17) family members are key players in regulating the immune response in mammals. Here, we identified the IL-17C and IL-17D homologs from large yellow croaker (Larimichthys crocea), named LcIL-17C and LcIL-17D, respectively. The deduced LcIL-17C and LcIL-17D proteins possessed the typical IL-17 domain and shared a conserved arrangement of eight cysteine residues. Both LcIL-17C and LcIL-17Dc genes were constitutively expressed in all tissues examined, although at different levels. After challenge with Aeromonas hydrophila, the expression of LcIL-17C and LcIL-17D was significantly increased in gills, head kidney, and spleen. In the peripheral blood leukocytes (PBLs), the recombinant LcIL-17C (rLcIL-17C) could strongly promote the expression of chemokines (CXCL8, CXCL12, and CXCL13), proinflammatory factors (TNF-α, IL-1β, IL-6, and IFNg), and antibacterial peptide hepcidin, whereas rLcIL-17D induced a weaker expression of these chemokines. Consistently, the culture supernatants from the PBLs treated by rLcIL-17C showed a stronger ability to induce the migration of PBLs than those treated by rLcIL-17D. Furthermore, both rLcIL-17C and rLcIL-17D could activate the NF-κB signalling in the epithelioma papulosum cyprini (EPC) cells. Taken together, these results indicated that LcIL-17C and LcIL-17D, although differing in their ability to mediate chemotaxis for PBLs, may promote the inflammatory response and host defence via activating NF-κB signalling. To our knowledge, this is the first report on functional identification of a IL-17C in teleost.

IL-17C mediates the recruitment of tumor-associated neutrophils and lung tumor growth.

Chronic obstructive pulmonary disease (COPD) is associated with an increased risk for lung cancer and an aberrant microbiota of the lung. Microbial colonization contributes to chronic neutrophilic inflammation in COPD. Nontypeable Haemophilus influenzae (NTHi) is frequently found in lungs of stable COPD patients and is the major pathogen triggering exacerbations. The epithelial cytokine interleukin-17C (IL-17C) promotes the recruitment of neutrophils into inflamed tissues. The purpose of this study was to investigate the function of IL-17C in the pulmonary tumor microenvironment. We subjected mice deficient for IL-17C (IL-17C-/-) and mice double deficient for Toll-like receptor 2 and 4 (TLR-2/4-/-) to a metastatic lung cancer model. Tumor proliferation and growth as well as the number of tumor-associated neutrophils was significantly decreased in IL-17C-/- and TLR-2/4-/- mice exposed to NTHi. The NTHi-induced pulmonary expression of IL-17C was dependent on TLR-2/4. In vitro, IL-17C increased the NTHi- and tumor necrosis factor-α-induced expression of the neutrophil chemokines keratinocyte-derived chemokine and macrophage inflammatory protein 2 in lung cancer cells but did not affect proliferation. Human lung cancer samples stained positive for IL-17C, and in non-small cell lung cancer patients with lymph node metastasis, IL-17C was identified as a negative prognostic factor. Our data indicate that epithelial IL-17C promotes neutrophilic inflammation in the tumor microenvironment and suggest that IL-17C links a pathologic microbiota, as present in COPD patients, with enhanced tumor growth.

Interleukin 17C: Is It A Host Defense Factor In The Oral Innate Immunity?

Interleukin 17C: Is It A Host Defense Factor In The Oral Innate Immunity?

IL-17A-mediated expression of epithelial IL-17C promotes inflammation during acute Pseudomonas aeruginosa pneumonia.

Lung epithelial cells are suggested to promote pathogen-induced pulmonary inflammation by the release of chemokines, resulting in enhanced recruitment of circulating leukocytes. Recent studies have shown that the interleukin-17C (IL-17C) regulates innate immune functions of epithelial cells in an autocrine manner. The aim of this study was to investigate the contribution of IL-17C to pulmonary inflammation in a mouse model of acute Pseudomonas aeruginosa pneumonia. Infection with P. aeruginosa resulted in an increased expression of IL-17C in lung tissue of wild-type mice. Numbers of neutrophils and the expression of the neutrophil-recruiting chemokines keratinocyte-derived chemokine and macrophage inflammatory protein 2 were significantly decreased in lungs of IL-17C-deficient (IL-17C-/-) mice infected with P. aeruginosa at 24 h. Systemic concentrations of interleukin-6 (IL-6) were significantly decreased in infected IL-17C-/- mice at 24 h and the survival of IL-17C-/- mice was significantly increased at 48 h. The expression of IL-17C was reduced in infected mice deficient for interleukin-17A (IL-17A), whereas pulmonary concentrations of IL-17A were not affected by the deficiency for IL-17C. Stimulation of primary alveolar epithelial cells with IL-17A resulted in a significantly increased expression of IL-17C in vitro. Our data suggest that IL-17A-mediated expression of epithelial IL-17C amplifies the release of chemokines by epithelial cells and thereby contributes to the recruitment of neutrophils and systemic inflammation during acute P. aeruginosa pneumonia.

Identification of genes differentially expressed in menstrual breakdown and repair.

Does the changing molecular profile of the endometrium during menstruation correlate with the histological profile of menstruation. We identified several genes not previously associated with menstruation; on Day 2 of menstruation (early-menstruation), processes related to inflammation are predominantly up-regulated and on Day 4 (late-menstruation), the endometrium is predominantly repairing and regenerating. Menstruation is induced by progesterone withdrawal at the end of the menstrual cycle and involves endometrial tissue breakdown, regeneration and repair. Perturbations in the regulation of menstruation may result in menstrual disorders including abnormal uterine bleeding. Endometrial samples were collected by Pipelle biopsy on Days 2 (n=9), 3 (n=9) or 4 (n=6) of menstruation. RNA was extracted from endometrial biopsies and analysed by genome wide expression Illumina Sentrix Human HT12 arrays. Data were analysed using 'Remove Unwanted Variation-inverse(RUV-inv)'. Ingenuity pathway analysis (IPA) and the Database for Annotation, Visualization and Integrated Discovery (DAVID) v6.7 were used to identify canonical pathways, upstream regulators and functional gene clusters enriched between Days 2, 3 and 4 of menstruation. Selected individual genes were validated by quantitative PCR. Overall, 1753 genes were differentially expressed in one or more comparisons. Significant canonical pathways, gene clusters and upstream regulators enriched during menstrual bleeding included those associated with immune cell trafficking, inflammation, cell cycle regulation, extracellular remodelling and the complement and coagulation cascade. We provide the first evidence for a role for glutathione-mediated detoxification (glutathione-S-transferase mu 1 and 2; GSTM1 andGSTM2) during menstruation. The largest number of differentially expressed genes was between Days 2 and 4 of menstruation (n=1176). We identified several genes not previously associated with menstruation including lipopolysaccharide binding protein, serpin peptidase inhibitor, clade B (ovalbumin), member 3 (SERPINB3) and -4 (SERPINB4), interleukin-17C (IL17C), V-set domain containing T-cell activation inhibitor 1 (VTCN1), proliferating cell nuclear antigen factor (KIAA0101/PAF), trefoil factor 3 (TFF3), laminin alpha 2 (LAMA2) and serine peptidase inhibitor, Kazal type 1 (SPINK1). Genes related to inflammatory processes were up-regulated on Day 2 (early-menstruation), and those associated with endometrial repair and regeneration were up-regulated on Day 4 (late-menstruation). Participants presented with a variety of endometrial pathologies related to bleeding status and other menstrual characteristics. These variations may also have influenced the menstrual process. The temporal molecular profile of menstruation presented in this study identifies a number of genes not previously associated with the menstrual process. Our findings provide valuable insight into the menstrual process and may present novel targets for therapeutic intervention in cases of endometrial dysfunction. All microarray data have been deposited in the public data repository Gene Expression Omnibus (GSE86003). Funding for this work was provided by a National Health and Medical Research Council of Australia (NHMRC) Project Grant APP1008553 to M.H., P.R. and J.G. M.H. is supported by an NHMRC Practitioner Fellowship. P.P. is supported by a NHMRC Early Career Fellowship. The authors have no conflict of interest to declare.

HSP70 is associated with the severity of inflammation in chronic rhinosinusitis.

Nasal secretions include cytokines and inflammatory mediators that are involved in the pathogenesis of upper airway inflammation. We tried to find unknown biomolecules that are involved in the pathogenesis of chronic rhinosinusitis (CRS). We collected nasal mucosal secretions from patients who were diagnosed as having CRS and who underwent endoscopic sinus surgery. A total of 63 patients who underwent nasal secretion collection were reviewed. Enzyme-linked immunosorbent assay was performed by using nasal lavage samples to evaluate which biomolecules were associated with the severity of inflammation based on the Lund-Mackay score. By using human nasal epithelial cells, we performed Western blot, real-time polymerase chain reaction, and enzyme-linked immunosorbent assay to evaluate the secretory mechanism of heat shock protein (HSP) 70. We found that the level of interleukin 8 and HSP70 were significantly associated with the Lund-Mackay score and interleukin 17C, C-X-C motif chemokine 10, and HSP27 were not significantly associated. HSP70 was also significantly associated with the surgical outcome of the enrolled patients. Furthermore, we found that exposure to hypoxia and treatment of lipoteichoic acid induced the secretion of HSP70 but that lipopolysaccharide did not induce the secretion of HSP70 in human nasal epithelial cells. Our findings indicated that HSP70 might play a role in the pathogenesis of CRS and the possibility of HSP70 as a biomolecule that represents the severity of CRS.

Smooth Muscle Cell-Derived Interleukin-17C Plays an Atherogenic Role via the Recruitment of Proinflammatory Interleukin-17A+ T Cells to the Aorta.

Atherosclerosis is characterized by frequent communication between infiltrating leukocytes and vascular cells, through chemokine and cytokine networks. Interleukin-17C (IL-17C) is detectable within atherosclerotic lesions; however, the potential involvement of this cytokine has not been examined. Thus, we sought to investigate the role of IL-17C in atherosclerosis. The expression of IL-17 cytokines was profiled within aortas of apolipoprotein E double knockout (Apoe(-/-)) mice, and Il17c expression was elevated. Flow cytometry experiments revealed a major population of aortic IL-17C-producing smooth muscle cells. Next, we generated Il17c(-/-)Apoe(-/-) mice and demonstrated that atherosclerotic lesion and collagen content was diminished within Western diet-fed Il17c(-/-)Apoe(-/-) aortas and aortic roots in comparison to Apoe(-/-) controls. Smooth muscle cells and fibroblasts were mainly responsible for the reduced Col1A1 expression in the aorta of Il17c(-/-)Apoe(-/-) mice. Importantly, IL-17C-treated Apoe(-/-) aortas showed upregulated Col1A1 expression ex vivo. Il17c(-/-)Apoe(-/-) mice displayed a proportional reduction in aortic macrophages, neutrophils, T cells, T helper 1 cells, and T regulatory cells, without corresponding changes in the peripheral immune composition. Examination of aortic IL-17A(+) T-cell receptor γδ T cells and Th17 cells demonstrated a stark reduction in the percentage and number of these subsets within Il17c(-/-)Apoe(-/-) versus Apoe(-/-) mice. Explanted 12-week Western diet-fed Apoe(-/-) aortas treated with IL-17C resulted in the induction of multiple vascular chemokines and cytokines. Th17 cells demonstrated attenuated migration toward supernatants from cultures of Il17c(-/-)Apoe(-/-) smooth muscle cells, and short-term homing experiments revealed diminished recruitment of Th17 cells to the aorta of Il17c(-/-)Apoe(-/-) recipients. Smooth muscle cell-derived IL-17C plays a proatherogenic role by supporting the recruitment of Th17 cells to atherosclerotic lesions.

Epigenetic characteristics in inflammatory candidate genes in aggressive periodontitis

BackgroundPeriodontitis is a chronic inflammatory disease triggered by the host immune response. Epigenetic modifications also affect the immune response. We assessed CpG methylation in 22 inflammatory candidate genes (ATF2, CCL25, CXCL14, CXCL3, CXCL5, CXCL6, FADD, GATA3, IL10RA, IL12A, IL12B, IL13, IL13RA1, IL15, IL17C, IL17RA, IL4R, IL6R, IL6ST, IL7, INHA, and TYK2) with respect to the occurrence of aggressive periodontitis (AgP). Patients and methodsIn this study 15 AgP patients (53.3% males, 41.4±10.5years) and 10 controls (40.0% males, 36.9±17.5years) were included. The methylation patterns of gingival biopsies were quantified using EpiTect® Methyl Signature PCR Array Human Inflammatory Response. ResultsIn gingival biopsies taken from patients with AgP, CpG methylation of CCL25 (1.73% vs. 2.59%, p=0.015) and IL17C (6.89% vs. 19.27%, p=0.002) was significantly reduced as compared with periodontally healthy tissues. DiscussionWe showed for the first time a differential methylation pattern for CCL25 and IL17C in periodontitis. CCL25 plays an important role in T-cell development, whereas IL17C regulates innate epithelial immune responses. The decrease in CpG methylation is presumably accompanied by an increase in gene expression. This could lead to a greater availability of CCL25 and interleukin 17C and support periodontal loss of attachment.

Increased beta 2 defensin in recurrent aphthous ulcer.

It was hypothesized that beta 2 defensin (BD-2) is increased in RAU lesions compared with healthy controls to promote anti-microbial host defence. RAU and control mucosa samples were subjected to quantitative real-time PCR and immunostained for BD-2, CD68, mast cell tryptase and 4-hydroxynonenal (4HNE). The effect of tumour necrosis factor-α (TNF-α)±interleukin-17C (IL-17C), without and with vitamin K3, was studied on BD-2 expression in epithelial SCC-25 cells. Although BD-2 mRNA did not differ between healthy and RAU mucosa, BD-2 stained strongly in acute-phase RAU epithelium (P=0.001). In controls, subepithelial BD-2(+) cells were mast cells and macrophages, whereas in RAU, most infiltrating leucocytes were BD-2(+) (P=0.004). In cell culture, BD-2 was increased 124-fold by TNF-α (P<0.0001) and 208-fold synergistically together with IL-17C (P<0.0001). 4HNE staining of RAU epithelium was not significantly increased, and vitamin K3-induced reactive oxygen species (ROS) did not affect BD-2. Anti-microbial BD-2 was not affected by oxidative stress but was highly increased in the epithelial and immigrant cells in the acute-phase RAU lesions, probably in part synergistically by TNF-α and epithelial IL-17C, which are known to be induced by activation of danger-signal receptors by pathogen- and/or damage-associated molecular patterns.

IL-17C expression in nasal epithelial cells of chronic rhinosinusitis with nasal polyposis

Interleukin 17C (IL-17C) is a functionally distinct member of the IL-17 family that is selectively induced in epithelia by bacterial challenge and inflammatory stimuli. The goal of this study was to explore the expression of IL-17C in nasal epithelial cells and their role in the pathogenesis of chronic rhinosinusitis with nasal polyposis (CRSwNPs). IL-17C expression was detected using immunohistochemistry (IHC) of the epithelial cell layers and using the western blot assay on whole tissue homogenates from control subjects (n=10) and CRSwNP patients [10 non-eosinophilic polyps and 10 eosinophilic polyps (EPs)]. Expression of IL-17C and P47-phox were evaluated in the human nasal epithelial cells (RPMI-2650 cells) after treatment with staphylococcal enterotoxin B (SEB) and pretreatment with reactive oxygen species (ROS) scavenger, N-acetyl L-cysteine (NAC). Finally, IL-17C expression was demonstrated in eosinophilic rhinosinusitis murine model using IHC. Epithelial expression of IL-17C was higher in nasal polyps (especially in EPs) compared to control mucosa. SEB increased the expression of IL-17C and P47-phox in RPMI-2650 cells. SEB-induced expressions of both IL-17C and P47-phox were significantly decreased in NAC-pretreated cells. Epithelial expression of IL-17C was significantly higher in experimental mice compared to control mice. SEB-induced IL-17C expression in nasal epithelial cells is mediated by ROS production. This pathway may be associated with the pathogenesis of CRSwNP, especially eosinophilic nasal polyps.

IL‐17C and its receptor IL‐17RA/IL‐17RE identify human oral epithelial cell as an inflammatory cell in recurrent aphthous ulcer

Recurrent aphthous ulcer (RAU) is an ulcerative disease of non-keratinized oral mucosa. Colon and bronchial epithelial cells produce interleukin-17C (IL-17C) upon stimulation of Toll-like receptor 2 (TLR2), TLR3 and TLR5, which are highly expressed in epithelial cells in RAU lesions. We therefore investigated the eventual presence and function of IL-17C in cultured human oral keratinocytes (HOK) and control biopsies compared to RAU lesions. Expression of IL-17A, IL-17C, IL-17RA and IL-17RE was analysed in cultured HOK cells using quantitative real-time polymerase chain reaction (qRT-PCR). HOK cells were stimulated with IL-17C and analysed for IL-8 and tumour necrosis factor-α (TNF-α) using qRT-PCR. Control mucosa (n = 5) was immunostained for IL-17A, IL-17C, IL-8, TNF-α and mast cell tryptase and compared with RAU lesions (n = 5) using the mean grey scale value. IL-17C, but no IL-17A, mRNA was found in cultured HOK cells. Components of the heterodimeric IL-17RA/IL-17RE receptor for IL-17C were also highly expressed. Stimulation of HOK with IL-17C increased TNF-α mRNA (P = 0.03; IL-8 increase was not statistically significant). HOK in RAU lesions stained intensively for IL-17C compared to controls (P = 0.006). This was associated with increased epithelial immunostaining of TNF-α (P = 0.04) and IL-8 (P = 0.02). Most of the inflammatory cells which stained for IL-17A in control mucosa and RAU lesions were also mast cell tryptase positive. IL-17C is highly expressed in epithelial cells in RAU lesions, where it seems to stimulate oral keratinocytes via IL-17RA/IL-17RE to produce pro-inflammatory cytokines. Human oral epithelial cells are probably important inflammatory cells in RAU.

IL-17C regulates the innate immune function of epithelial cells in an autocrine manner

Interleukin 17C (IL-17C) is a member of the IL-17 family that is selectively induced in epithelia by bacterial challenge and inflammatory stimuli. Here we show that IL-17C functioned in a unique autocrine manner, binding to a receptor complex consisting of the receptors IL-17RA and IL-17RE, which was preferentially expressed on tissue epithelial cells. IL-17C stimulated epithelial inflammatory responses, including the expression of proinflammatory cytokines, chemokines and antimicrobial peptides, which were similar to those induced by IL-17A and IL-17F. However, IL-17C was produced by distinct cellular sources, such as epithelial cells, in contrast to IL-17A, which was produced mainly by leukocytes, especially those of the T(H)17 subset of helper T cells. Whereas IL-17C promoted inflammation in an imiquimod-induced skin-inflammation model, it exerted protective functions in dextran sodium sulfate-induced colitis. Thus, IL-17C is an essential autocrine cytokine that regulates innate epithelial immune responses.

Orphan Cytokine Reveals IL-17 Family Secret

The biology of interleukin-17C (IL-17C) has remained largely a mystery for more than a decade. Chang etal. (2011), in this issue of Immunity, and two other reports (Song etal., 2011; Ramirez-Carrozzi etal., 2011) demonstrate that IL-17C has broad functions in a variety of tissues.

Tumor Necrosis Factor α-Mediated Induction of Interleukin 17C in Human Keratinocytes Is Controlled by Nuclear Factor κB

IL-17C is a member of the IL-17 family of cytokines. The expression of IL-17C has been demonstrated to be strongly induced by TNFα in human keratinocytes, and recently the level of IL-17C was found to be increased in the inflammatory skin disease psoriasis. However, little is known about the molecular mechanisms involved in the regulation of IL-17C. Here, we show that pretreatment of cultured human keratinocytes with the inhibitor of κB kinase 2 inhibitor, SC-514, resulted in a significant reduction in both IL-17C mRNA and protein expression, indicating the significance of this pathway in the regulation of IL-17C. NF-κB binding sites were identified upstream from the IL-17C gene, and by electrophoretic mobility shift assay NF-κB was shown to bind to all three identified binding sites. Moreover, NF-κB binding to these sites was inducible by TNFα. Supershift analysis revealed binding of the NF-κB subunits p65 and p50 to all three NF-κB binding sites. To determine the contribution of NF-κB in IL-17C expression, we conducted luciferase gene reporter experiments and demonstrated that a 3204-bp promoter fragment of IL-17C containing three putative NF-κB binding sites was strongly activated by TNFα. Interestingly, mutations of the three NF-κB binding sites revealed that one specific NF-κB binding site was crucial for the TNFα-mediated IL-17C induction because mutation of this specific site completely abolished TNFα-induced IL-17C promoter activation. We conclude that the activation of NF-κB (p65/p50) is crucial for the TNFα-induced stimulation of IL-17C expression in human keratinocytes.