IL-17B: A new area of study in the IL-17 family

The interleukin (IL)-17 superfamily, a relatively new family of cytokines, consists of six ligands (from IL-17A to IL-17F), which bind to five receptor subtypes (from IL-17RA to IL-17RE) and induce downstream signaling. IL-17A, a prototype member of this family, has been reported to be involved in the pathogenesis of allergies, autoimmune diseases, allograft transplantations, and malignancies. Unlike IL-17A, which is mainly produced by T helper 17 cells, IL-17B is widely expressed in various tissues. Recently, the biological function of IL-17B in diseases, particularly tumors, has attracted the attention of researchers. We previously reported that the expression of IL-17RB increased in gastric cancer tissues and demonstrated that IL-17B/IL-17RB signaling plays a critical role in gastric tumor progression. However, studies on IL-17B are scant. In this review, we detail the structural characteristics, expression patterns, and biological activities of IL-17B and its potential role in the pathogenesis of diseases.     

Prevention of antigen-induced bronchoconstriction by lodoxamide ethyl,a new orally active antiallergic drug

Lodoxamide ethyl, an orally active drug with pharmacologic activity similar to that of cromolyn sodium, blocks passive cutaneous anaphylaxis (PCA) in rats and antigen-induced bronchoconstriction in guinea pigs and monkeys. Its effectiveness in preventing antigen-induced airway obstruction was studied in 12 asymptomatic asthmatic adults with immediate skin test sensitivity to ragweed, Alternaria, or animal dander. The dose required to reduce the forced expiratory volume in 1 sec (FEV₁) by 20% (PD₂₀) was determined by dosimeter bronchoprovocation challenge with the appropriate antigen. At 1-wk intervals each subject received either placebo or 1, 3, or 10 mg drug in a randomized, double-blind fashion 30 min prior to starting bronchoprovocation challenge. On average, 1 mg increased the PD₂₀ fivefold, 3 mg about sixfold, and 10 mg about 27-fold. Dose-related side effects began 10 min after drug and lasted up to 40 min. Thus the oral administration of lodoxamide ethyl was effective in preventing antigen-induced bronchoconstriction, and both the beneficial effects and side effects are dose related.     

Immunomodulating effects of the new anti-rheumatic drug tenidap on collagen-induced arthritis

We investigated the in vivo action of the newly developed anti-rheumatic agent tenidap, CP-66,248 (Pfizer Inc., New York), on arthritis in collagen-induced arthritic mice. The inhibitory effect of tenidap on the development of arthritis was statistically more significant than piroxicam. The serum anti-type II collagen antibody titer was markedly inhibited in the mice treated by tenidap. These results suggest that, unlike NSAIDs, tenidap inhibits the progress of collagen-induced arthritis through its immunomodulating effect.     

Neutralization of IL-17 by active vaccination inhibits IL-23-dependent autoimmune myocarditis

The most common reason for heart failure in young adults is dilated cardiomyopathy often resulting from myocarditis. Clinical studies and animal models provide evidence that an autoimmune response against heart myosin is the underlying reason for the disease. IL-12 has been suggested to play a key role in development of experimental autoimmune myocarditis (EAM), as IL-12p40 and IL-12Rbeta1 knockouts are protected from disease. In this study, we have compared IL-12p40-/- mice, IL-12p35-/- mice and mice treated with a neutralizing IL-23 antibody in EAM and found that in fact IL-23, not IL-12, is responsible for inflammatory heart disease. However, these cytokines appear to have redundant activity for priming and expansion of autoreactive CD4 T cells, as specific T cell proliferation was only defective in the absence of both cytokines. IL-23 has been suggested to promote a pathogenic IL-17-producing T cell population. We targeted IL-17 by capitalizing on an active vaccination approach that effectively breaks B cell tolerance. Neutralization of IL-17 reduced myocarditis and heart autoantibody responses, suggesting that IL-17 is the critical effector cytokine responsible for EAM. Thus, targeting of IL-23 and IL-17 by passive and active vaccination strategies holds promise as a therapeutic approach to treat patients at risk for development of dilated cardiomyopathy.     

IL-17/IL-17R与恶性肿瘤

IL-17是新近被确认的一种细胞因子,由T细胞、中性粒细胞等产生,其靶细胞分布广泛。IL-17具有强大的招募中性粒细胞、促进多种细胞释放炎性因子、促进细胞增殖的作用,被认为参与了机体多种炎症疾病、自身免疫性疾病和肿瘤等的发生,本文就IL-17/IL-17R在肿瘤中的研究进展做一综述。     

IL-17: A new actor in IFN-driven systemic autoimmune diseases

Systemic autoimmune diseases such as systemic lupus erythematosus are type I IFN-driven diseases with exaggerated B-cell responses and autoantibody production. Th17 cells, a T-helper-cell subset with high inflammatory capacity, was initially discovered and characterized in the context of experimental autoimmune encephalomyelitis - an animal model of multiple sclerosis. There is now emerging evidence that Th17 cells, and more generally IL-17 and IL-17-producing cells, may play a role in the pathogenesis of type I IFN-driven systemic autoimmune diseases such as lupus. Here, we review the different studies suggesting a role for IL-17 and IL-17-producing cells in systemic autoimmune diseases, both in humans and in animal models, and we consider the possible mechanisms by which these cells may contribute to disease. We also discuss the hypothesis that type I IFN and IL-17 act in concert to sustain and amplify autoimmune and inflammatory responses, making them a dangerous combination involved in the pathogenesis of systemic autoimmune diseases.     

Monocytes differentiated with GM-CSF and IL-15 initiate Th17 and Th1 responses that are contact-dependent and mediated by IL-15

Distinct types of DCs are generated from monocytes using GM-CSF with IL-4 (IL4-DC) or IL-15 (IL15-DC). IL15-DCs are potent inducers of antigen-specific CD8(+) T cells, display a phenotype similar to CD14(+) cells commonly described in chronically inflamed tissues, and produce high levels of IL-1β and IL-15 in response to TLR4 stimulation. As these cytokines promote Th17 responses, which are also associated with inflammatory diseases, I hypothesized that TLR-primed IL15-DCs favor Th17 activation over IL4-DCs. Compared with IL4-DCs, IL15-DCs stimulated with TLR agonists secreted significantly higher concentrations of the Th17-promoting factors, IL-1β, IL-6, IL-23, and CCL20, and lower levels of the Th1 cytokine, IL-12. In addition, IL15-DCs and not IL4-DCs up-regulated IL-15 on the cell surface in response to TLR agonists. IL15-DCs primed with TLR3 or TLR4 agonists triggered Th17 (IL-17, IL-22, and/or IFN-γ) and Th1 (IFN-γ) responses, whereas IL4-DCs primed with the same TLR agonists activated Th1 (IFN-γ) responses. Secretion of IL-17 and IFN-γ required contact with TLR-primed IL15-DC, and IFN-γ production was mediated by membrane-bound IL-15. These findings identify key differences in monocyte-derived DCs, which impact adaptive immunity, and provide primary evidence that IL-15 promotes Th17 and Th1 responses by skewing monocytes into IL15-DC.     

Clinical associations between IL-17 family cytokines and periodontitis and potential differential roles for IL-17A and IL-17E in periodontal immunity

Objective

IL-17A is implicated in periodontitis pathogenesis. The roles of IL-17B–IL-17F and IL-17A/F are unknown. This study aimed to determine clinical associations between IL-17 family cytokines and periodontitis and to investigate the biological roles of IL-17A and IL-17E using in vitro model systems.

Materials and methods

Samples from 97 patients with periodontitis and 77 healthy volunteers were used in the study. Serum, saliva and gingival crevicular fluid (GCF) levels of IL-17 family cytokines were measured by ELISA. Oral keratinocytes were stimulated with a P. gingivalis biofilm, or IL-17A, in the presence and absence of IL-17E and the expression of IL-8 and CXCL5 were investigated by ELISA and real-time-PCR. NF-κB phosphorylation in similar experiments was also measured using a cell-based ELISA.

Results

Serum, saliva and GCF IL-17A levels were higher in periodontitis patients and correlated positively with clinical parameters of attachment loss, pocket depth and bleeding on probing. Serum IL-17E levels were lower in periodontitis patients and the serum IL-17A:IL-17E ratio correlated positively with clinical parameters. In vitro, IL-17E inhibited Porphyromonas gingivalis and IL-17A induced expression of chemokines by reducing phosphorylation of the NF-κB p65 subunit.

Conclusions

Serum IL-17A:IL-17E may be a marker of disease severity. IL-17E may have opposing roles to IL-17A in periodontitis pathogenesis. IL-17E can negatively regulate IL-17A and periodontal pathogen induced expression of chemokines by oral keratinocytes.     

胃癌组织中IL-17A和IL-17F的表达及意义

目的探讨胃癌组织中促炎因子IL-17A和IL-17F的表达及其对临床预后的影响。方法采用免疫组化SP法检测41例胃癌组织和26例癌旁组织(对照组)中IL-17A和IL-17F的表达,分析IL-17A和IL-17F与胃癌患者临床病理特征的关系。结果胃癌组织中IL-17A和IL-17F的阳性率及中～强阳性率均明显高于对照组(P<0.01)。胃癌组织中IL-17A和IL-17F表达与临床分期、淋巴结转移均呈正相关(P<0.001),与患者性别、年龄及病理分化程度均无相关性(P>0.05)。胃癌组织中IL-17A和IL-17F的表达呈正相关(r=0.407,P<0.009)。结论 IL-17A和IL-17F促进了胃癌的发生、发展,且其高表达预示预后不良。IL-17A和IL-17F作用机制相似。     

Correlation between acute myeloid leukemia and IL-17A,IL-17F,and IL-23R gene polymorphism

Recent studies have shown that Th17 cells may be involved in the pathological process of acute myeloid leukemia. This CD4+ cell subgroup secretes highly homologous interleukin (IL)-17A and IL-17F, and also expresses IL-23 receptor (IL-23R) on the cell surface. Our study aims to investigate the relationship of IL-17A, IL-17F, and IL23R with disease susceptibility, and clarify the relationship between gene polymorphism variation and serum IL-17 level. 62 acute myeloid leukemia patients and 125 healthy controls were included in this study. Restriction fragment length polymorphism polymerase chain reaction (PCR-RFLP) was applied to analyze IL-17A (rs2275913; G-197A), IL17F (rs763780; A7488G; His161Arg), and IL-23R (rs11209026, G1142A; Arg381Gln) alleles. At the same time, enzyme-linked immunoassay analysis (ELISA) was used to test serum IL-17 level in patients. Acute myeloid leukemia patients presented higher rate of IL-17F G single mutant (RR = 4.75, P < 0.001) and GG mutation homozygote (RR = 23.01, P < 0.005). While IL-17A, IL-23R A single mutant and purified AA mutation homozygote showed no correlation with acute myeloid leukemia susceptibility. In addition, ELISA showed that serum IL-17 exhibited no significant difference between acute myeloid leukemia patients and healthy controls had (8.8 ± 7.19 pg/ml vs. 1.4 ± 0.2 pg/ml, P > 0.05). IL-17F G single mutant and GG mutation homozygote were correlated with acute myeloid leukemia susceptibility, while IL-17 gene polymorphism and serum IL-17 level were not. Furthermore, IL-17A and IL-23R gene polymorphism were not associated with acute myeloid leukemia susceptibility.     

Association of IL-17A and IL-17F polymorphisms with gastric cancer risk in Asians: A meta-analysis

Increasing number of studies focused on the association of IL-17A rs2275913 and IL-17F rs763780 polymorphisms with gastric cancer (GC) risk. However, the results were inconsistent. To elucidate the exact association, we performed the present meta-analysis. Databases including PubMed, Web of knowledge and Chinese National Knowledge Infrastructure (CNKI) were systematically searched for potentially eligible literatures. Odds ratios (OR) and their 95% confidence interval (CI) were used to evaluate the strength of association. Eight studies for IL-17A rs2275913 (3345 cases and 4427 controls) and five studies for IL-17F rs763780 (1784 cases and 2592 controls) were finally included. The results indicated that individuals with AA genotype of IL-17A rs2275913 polymorphism were associated with increased GC risk compared with wild-type GG (OR = 1.61, 95% CI = 1.17–2.23, P = 0.004); A allele was significantly associated with increased GC risk compared with G allele (OR = 1.22, 95% CI = 1.06–1.41, P = 0.007). IL-17F rs763780 polymorphism was also significantly associated with increased GC risk (CC vs. CT: OR = 1.40, 95% CI = 1.04–1.88, P = 0.025; CT vs. TT: OR = 1.35, 95% CI = 1.16–1.58, P < 0.001; C allele vs. T allele: OR = 1.30, 95% CI = 1.15–1.47, P < 0.001). In summary, IL-17A rs2275913 A/G polymorphism and IL-17F rs763780 C/T polymorphism might be associated with increased GC risk in Asians. Further large-scale studies are still required to confirm the results of this meta-analysis.     

A Distinct Regulatory Role of Th17 Cytokines IL-17A and IL-17F in Chemokine Secretion from Lung Microvascular Endothelial Cells

Th17 cytokines IL-17A and IL-17F play a critical role in the activation and recruitment of neutrophils at airway inflammation mainly through the induction of CXC chemokines in the lungs. Vascular endothelial cells belong to the category of major CXC chemokine-producing cells. However, until now, the precise role of Th17 cytokines in CXC chemokine secretion in lung microvascular endothelial cells (LMVECs) has not been fully elucidated. In this study, we examined the biological effects of Th17 cytokines IL-17A and IL-17F on CXCL1, CXCL5, and CXCL8 release in LMVECs. Both IL-17 receptor A (IL-17RA) and IL-17RC are expressed on the surface of LMVECs. In contrast to IL-17F, IL-17A significantly upregulated CXCL1 mRNA expression and protein release, whereas both IL-17A and IL-17F did not have the ability to induce CXCL5 and CXCL8 secretion in LMVECs. IL-17A and IL-17F displayed positive regulatory effects on IL-1β-induced CXCL1, CXCL5, and CXCL8 secretion. On the other hand, IL-17A enhanced the upregulating effect of TNF-α on CXCL1, CXCL5, and CXCL8 release, whereas IL-17F had a negative regulatory effect on TNF-α-mediated secretion. Th2 cytokines IL-4 and IL-13 showed an inhibitory effect on IL-1β plus IL-17A-induced CXCL1, CXCL5, and CXCL8 secretion, but displayed a positive regulatory effect on TNF-α plus IL-17A-induced secretion. These results provide evidence that Th17 cytokines IL-17A and IL-17F have a distinct regulatory role in CXCL1, CXCL5, and CXCL8 expression in LMVECs stimulated either with IL-1β or with TNF-α. Our findings also suggest that CXC chemokine secretion in LMVECs may be complicatedly regulated by Th17 cytokines, Th2 cytokines, and macrophage-associated cytokines in pathological conditions such as bronchial asthma.     

Characterization of interleukin-15 (IL-15) and the IL-15 receptor complex

IL-15 interacts with a heterotrimeric receptor that consists of the and subunits of the IL-2 receptor (IL-2R) as well as a specific, high-affinity IL-15-binding subunit, which is designated IL-15R. Since both the and the subunits of the IL-2R are required for signaling by either IL-2 or IL-15, it is not surprising that these cytokines share many activitiesin vitro. However, the differential expression of these cytokines and the chains of their receptors within various tissues and cell types suggests that IL-2 and IL-15 may perform at least partially distinct physiological functions. The production of IL-15 by macrophages, and possibly other cell types, in response to environmental stimuli and infectious agents suggests that IL-15 may play a role in protective immune responses, allograft rejection, and the pathogenesis of autoimmune diseases.     

由胰岛素信号通路筛选糖尿病药物作用靶点

胰岛素是维持血糖稳定的一种重要激素,通过效应细胞受体将胰岛素信号传递到细胞内,引发胞内一系列反应而发挥功能。随着对胰岛素信号通路的了解逐渐增多,已经从中筛选到一些用于治疗糖尿病的药物作用靶点,它们主要涉及增强靶细胞对胰岛素的敏感性和促进对葡萄糖的利用等环节。     

IL-17RC: a partner in IL-17 signaling and beyond

The interleukin (IL)-17 cytokine family members IL-17A and IL-17F mediate inflammatory activities via the IL-17 receptor (IL-17R) complex, comprised of the IL-17RA and IL-17RC subunits. Proper regulation of the IL-17 signaling axis results in effective host defense against extracellular pathogens, while aberrant signaling can drive autoimmune pathology. Elucidating the molecular mechanisms underlying IL-17 signal transduction can yield an enhanced understanding of inflammatory immune processes and also create an avenue for therapeutic intervention in the treatment of IL-17-dependent diseases. To date, the fundamental signaling mechanisms used by the IL-17R complex are still incompletely defined. While current structure–function studies have primarily focused on the IL-17RA subunit, recent research indicates that the IL-17RC subunit plays a key role in modulating IL-17 responses. This review will examine what is known regarding IL-17RC function and provide a framework for future work on this subunit and its impact on human health.