IL-17-producing alveolar macrophages mediate allergic lung inflammation related to asthma

B lymphocytes regulate airway granulocytic inflammation and cytokine production in a murine model of fungal allergic asthma

Sensitization to fungi often leads to a severe form of asthma that is particularly difficult to manage clinically, resulting in increased morbidity and hospitalizations in these patients. Although B lymphocytes might exacerbate asthma symptoms through the production of IgE, these cells might also be important in the protective response against inhaled fungi. Through cytokine release and T-cell interactions, these lymphocytes might also influence the development and maintenance of airway wall fibrosis. J(H)(-/-) mice lack the JH gene for the heavy chain component of antibodies, which is critical for B-cell function and survival. These animals have facilitated the elucidation of the role of B lymphocytes in a number of immune responses; however, J(H)(-/-) mice have not been used to study fungal allergy. In this study, we examined the role of B lymphocytes using an Aspergillus fumigatus murine fungal aeroallergen model that mimics human airway disease that is triggered by environmental fungal exposure. We compared disease progression in sensitized wild-type BALB/c and J(H)(-/-) mice that were exposed to repeated fungal exposure and found no differences in airway hyperresponsiveness, overall pulmonary inflammation or collagen deposition around the large airways. However, the levels of the Th2-type cytokines IL-4 and IL-13 were significantly attenuated in the airways of J(H)(-/-) mice relative to the BALB/c controls. By contrast, levels of the inflammatory cytokines IL-17A and IL-6 were significantly elevated in the J(H)(-/-) animals, and there was significantly more robust airway eosinophilia and neutrophilia than in control animals. Taken together, these findings demonstrate that B lymphocytes help to regulate granulocytic responses to fungal exposure in the pulmonary compartment.

Der p2 recombinant bacille Calmette-Guerin priming of bone marrow-derived dendritic cells suppresses Der p2-induced T helper17 function in a mouse model of asthma

BACKGROUND AND OBJECTIVE

Previous studies have demonstrated that our recombinant bacille Calmette-Guerin (rBCG), which expresses Der p2 in house dust mite (Der p2 rBCG) suppresses asthmatic airway inflammation by regulating the phenotype and function of dendritic cells (DC) and reprogramming T helper (Th) 0 cell differentiation into different T cell (Th1/Th2/Treg) subtypes. However, the exact role of Der p2 rBCG in reprogramming Th17 differentiation and the relevant mechanisms are not known. The aim of this study was to examine whether Der p2 rBCG-mediated inhibition of allergic airway inflammation is mediated by regulating Th17 differentiation in a murine asthma model.

METHODS

Primary mouse bone marrow-derived dendritic cells (BMDC) were infected with Der p2 rBCG and adoptively transferred to Der p2-intranasally sensitized mice. The role of Der p2 rBCG-BMDC on the regulation of airway inflammation and Th17 cell differentiation was assessed.

RESULTS

Adoptive transfer of Der p2 rBCG-BMDC suppressed airway inflammation and mucin secretion. Der p2 rBCG-BMDC inhibited excessive Th17 immune responses but not BCG-BMDC. Furthermore, Der p2 rBCG decreased jagged-2 and increased delta-like-4 expressions on BMDC to a greater extent than BCG.

CONCLUSIONS

These findings suggest that DC plays a key role in Der p2 rBCG-induced immunoregulation. Der p2 rBCG also displayed a potent inhibitory effect on Th17 differentiation, and these findings increase our understanding of the cellular basis of Der p2 BCG-mediated inhibition of asthma.

Intratumor IL-17-positive mast cells are the major source of the IL-17 that is predictive of survival in gastric cancer patients

Interleukin-17 (IL-17) is prevalent in tumor tissue and suppresses effective anti-tumor immune responses. However, the source of the increased tumor-infiltrating IL-17 and its contribution to tumor progression in human gastric cancer remain poorly understood. In this study, we enrolled 112 gastric cancer patients, immunofluorescence was used to evaluate the colocalization of CD3, CD4, CD56, CD20, CD68, and mast cell tryptase (MCT) with IL-17. Immunohistochemistry was used to evaluate the distribution of microvessel density (CD34), CD66b⁺, CD68⁺, and FoxP3⁺ cells in different microanatomical areas. Prognostic value was determined by Kaplan-Meier analysis and a Cox regression model. The results showed that mast cells, but not T cells or macrophages, were the predominant cell type producing IL-17 in gastric cancer. Significant positive correlations were detected between densities of mast cell-derived IL-17 and microvessels, neutrophils, and regulatory T cells (Tregs). Futhermore, we found that the majority of vascular endothelial cells expressing Interleukin-17 receptor (IL-17R). Kaplan-Meier analysis revealed that increasing intratumor infiltrated mast cells and IL-17⁺ cells, as well as MCT⁺ IL-17⁺ cells, were significantly associated with worse overall survival. These findings indicated that mast cells were the major source of IL-17 in gastric cancer, and intratumor IL-17 infiltration may have promoted tumor progression by enhancing angiogenesis in the tumor microenvironment through the axis of IL-17/IL-17R. IL-17-positive mast cells showed a prognostic factor in gastric cancer, indicating that immunotherapy targeting mast cells might be an effective strategy to control intratumor IL-17 infiltration, and consequently reverse immunosuppression in the tumor microenvironment, facilitating cancer immunotherapy.

Mannan induces ROS-regulated, IL-17A-dependent psoriasis arthritis-like disease in mice

Psoriasis (Ps) and psoriasis arthritis (PsA) are poorly understood common diseases, induced by unknown environmental factors, affecting skin and articular joints. A single i.p. exposure to mannan from Saccharomyces cerevisiae induced an acute inflammation in inbred mouse strains resembling human Ps and PsA-like disease, whereas multiple injections induced a relapsing disease. Exacerbation of disease severity was observed in mice deficient for generation of reactive oxygen species (ROS). Interestingly, restoration of ROS production, specifically in macrophages, ameliorated both skin and joint disease. Neutralization of IL-17A, mainly produced by γδ T cells, completely blocked disease symptoms. Furthermore, mice depleted of granulocytes were resistant to disease development. In contrast, certain acute inflammatory mediators (C5, Fcγ receptor III, mast cells, and histamine) and adaptive immune players (αβ T and B cells) were redundant in disease induction. Hence, we propose that mannan-induced activation of macrophages leads to TNF-α secretion and stimulation of local γδ T cells secreting IL-17A. The combined action of activated macrophages and IL-17A produced in situ drives neutrophil infiltration in the epidermis and dermis of the skin, leading to disease manifestations. Thus, our finding suggests a new mechanism triggered by exposure to exogenous microbial components, such as mannan, that can induce and exacerbate Ps and PsA.

Adjuvant-dependent regulation of interleukin-17 expressing γδ T cells and inhibition of Th2 responses in allergic airways disease

Background

Th2 immune responses are linked primarily to mild and moderate asthma, while Th17 cells, Interleukin-17A (IL-17) and neutrophilia have been implicated in more severe forms of disease. How Th2-dependent allergic reactions are influenced by Th17 and IL-17-γδ T cells is poorly understood. In murine models, under some conditions, IL-17 promotes Th2-biased airway inflammatory responses. However, IL-17-γδ T cells have been implicated in the inhibition and resolution of allergic airway inflammation and hyperresponsiveness (AHR).

Methods

We compared airway responses in Balb/c mice sensitized to OVA with (and without) a Th2-skewing aluminum-based adjuvant and the IL-17 skewing, complete Freund’s adjuvant (CFA). AHR was measured invasively by flexiVent, while serum OVA-IgE was quantified by an enzyme immunoassay. Airway inflammatory and cytokine profiles, and cellular sources of IL-17 were assessed from bronchoalveolar lavage and/or lungs. The role of γδ T cells in these responses was addressed in OVA/CFA sensitized mice using a γδ T cell antibody.

Results

Following OVA challenge, all mice exhibited mixed eosinophilic/neutrophilic airway inflammatory profiles and elevated serum OVA-IgE. Whereas OVA/alum sensitized mice had moderate inflammation and AHR, OVA/CFA sensitized mice had significantly greater inflammation but lacked AHR. This correlated with a shift in IL-17 production from CD4⁺ to γδ T cells. Additionally, OVA/CFA sensitized mice, given a γδ TCR stimulatory antibody, showed increased frequencies of IL-17-γδ T cells and diminished airway reactivity and eosinophilia.

Conclusions

Thus, the conditions of antigen sensitization influence the profile of cells that produce IL-17, the balance of which may then modulate the airway inflammatory responses, including AHR. The possibility for IL-17-γδ T cells to reduce AHR and robust eosinophilic inflammation provides evidence that therapeutic approaches focused on stimulating and increasing airway IL-17-γδ T cells may be an effective alternative in treating steroid resistant, severe asthma.

Electronic supplementary material

The online version of this article (doi:10.1186/s12931-014-0090-5) contains supplementary material, which is available to authorized users.

Effect of mouse strain in a model of chemical-induced respiratory allergy

The inhalation of many types of chemicals is a leading cause of allergic respiratory diseases, and effective protocols are needed for the detection of environmental chemical–related respiratory allergies. In our previous studies, we developed a method for detecting environmental chemical–related respiratory allergens by using a long-term sensitization–challenge protocol involving BALB/c mice. In the current study, we sought to improve our model by characterizing strain-associated differences in respiratory allergic reactions to the well-known chemical respiratory allergen glutaraldehyde (GA). According to our protocol, BALB/c, NC/Nga, C3H/HeN, C57BL/6N, and CBA/J mice were sensitized dermally with GA for 3 weeks and then challenged with intratracheal or inhaled GA at 2 weeks after the last sensitization. The day after the final challenge, all mice were euthanized, and total serum IgE levels were assayed. In addition, immunocyte counts, cytokine production, and chemokine levels in the hilar lymph nodes (LNs) and bronchoalveolar lavage fluids (BALF) were also assessed. In conclusion, BALB/c and NC/Nga mice demonstrated markedly increased IgE reactions. Inflammatory cell counts in BALF were increased in the treated groups of all strains, especially BALB/c, NC/Nga, and CBA/J strains. Cytokine levels in LNs were increased in all treated groups except for C3H/HeN and were particularly high in BALB/c and NC/Nga mice. According to our results, we suggest that BALB/c and NC/Nga are highly susceptible to respiratory allergic responses and therefore are good candidates for use in our model for detecting environmental chemical respiratory allergens.

mCLCA3 modulates IL-17 and CXCL-1 induction and leukocyte recruitment in murine Staphylococcus aureus pneumonia

The human hCLCA1 and its murine ortholog mCLCA3 (calcium-activated chloride channel regulators) are exclusively expressed in mucus cells and linked to inflammatory airway diseases with increased mucus production, such as asthma, cystic fibrosis and chronic obstructive pulmonary disease. Both proteins have a known impact on the mucus cell metaplasia trait in these diseases. However, growing evidence points towards an additional role in innate immune responses. In the current study, we analyzed Staphylococcus aureus pneumonia, an established model to study pulmonary innate immunity, in mCLCA3-deficient and wild-type mice, focusing on the cellular and cytokine-driven innate inflammatory response. We compared clinical signs, bacterial clearance, leukocyte immigration and cytokine responses in the bronchoalveolar compartment, as well as pulmonary vascular permeability, histopathology, mucus cell number and mRNA expression levels of selected genes (mClca1 to 7, Muc5ac, Muc5b, Muc2, Cxcl-1, Cxcl-2, Il-17). Deficiency of mCLCA3 resulted in decreased neutrophilic infiltration into the bronchoalveolar space during bacterial infection. Only the cytokines IL-17 and the murine CXCL-8 homolog CXCL-1 were decreased on mRNA and protein levels during bacterial infection in mCLCA3-deficient mice compared to wild-type controls. However, no differences in clinical outcome, histopathology or mucus cell metaplasia were observed. We did not find evidence for regulation of any other CLCA homolog that would putatively compensate for the lack of mCLCA3. In conclusion, mCLCA3 appears to modulate leukocyte response via IL-17 and murine CXCL-8 homologs in acute Staphylococcus aureus pneumonia which is well in line with the proposed function of hCLCA1 as a signaling molecule acting on alveolar macrophages.

Renal F4/80+ CD11c+ mononuclear phagocytes display phenotypic and functional characteristics of macrophages in health and in adriamycin nephropathy

Conventional markers of macrophages (Mфs) and dendritic cells (DCs) lack specificity and often overlap, leading to confusion and controversy regarding the precise function of these cells in kidney and other diseases. This study aimed to identify the phenotype and function of renal mononuclear phagocytes (rMPs) expressing key markers of both Mфs and DCs. F4/80(+)CD11c(+) cells accounted for 45% of total rMPs in normal kidneys and in those from mice with Adriamycin nephropathy (AN). Despite expression of the DC marker CD11c, these double-positive rMPs displayed the features of Mфs, including Mф-like morphology, high expression of CD68, CD204, and CD206, and high phagocytic ability but low antigen-presenting ability. F4/80(+)CD11c(+) cells were found in the cortex but not in the medulla of the kidney. In AN, F4/80(+)CD11c(+) cells displayed an M1 Mф phenotype with high expression of inflammatory mediators and costimulatory factors. Adoptive transfer of F4/80(+)CD11c(+) cells separated from diseased kidney aggravated renal injury in AN mice. Furthermore, adoptive transfer of common progenitors revealed that kidney F4/80(+)CD11c(+) cells were derived predominantly from monocytes, but not from pre-DCs. In conclusion, renal F4/80(+)CD11c(+) cells are a major subset of rMPs and display Mф-like phenotypic and functional characteristics in health and in AN.

Asthma research in China: a five-year review

Asthma is one of the most common chronic diseases worldwide with increasing morbidity. China has the largest asthmatic population and is one of the countries with the highest asthma mortality. Fortunately, asthma research in China, both clinical and scientific, has developed markedly over the past few years. This has resulted in significant increases in our understanding of Chinese asthma prevalence, risk factors, control status, pathogenesis, and new prevention or treatment strategies. In this review, the major achievements of asthma research in China from 2008 to 2012 are summarized.

Interleukin-17 cytokine signalling in patients with asthma

Asthma remains a global health problem and, therefore, more effective pharmacotherapy is needed. This is particularly true for chronic and severe asthma. In these clinical phenotypes, chronic inflammation involving neutrophils is likely to play a pathogenic role, making it interesting to target cytokine signalling involved in the accumulation of neutrophils. Therefore, it is of interest that the archetype T-helper 17 cell cytokine interleukin (IL)-17A, perhaps also IL-17F, controls neutrophil accumulation, mucus secretion, macrophage mobilisation and smooth muscle reactivity in various experimental airway models. However, much less is known about the involvement of signalling via IL-17 cytokines in humans with asthma. Existing evidence suggests that these cytokines are released from several types of immune cells in asthma and, for IL-17A, there is a local increase associated with disease severity, with the mobilisation of neutrophils and smooth muscle cells locally in the airways. Even though the causative role of IL-17 cytokines remains unclear, there is potential for clinical utility in targeting IL-17A specifically in patients with moderate-to-severe asthma and high reversibility. There is a need for new and well-powered clinical investigations of signalling via IL-17 cytokines in this clinical phenotype.

Macrophage activation state determines the response to rhinovirus infection in a mouse model of allergic asthma

Background

The mechanisms by which viruses cause asthma exacerbations are not precisely known. Previously, we showed that, in ovalbumin (OVA)-sensitized and -challenged mice with allergic airway inflammation, rhinovirus (RV) infection increases type 2 cytokine production from alternatively-activated (M2) airway macrophages, enhancing eosinophilic inflammation and airways hyperresponsiveness. In this paper, we tested the hypothesis that IL-4 signaling determines the state of macrophage activation and pattern of RV-induced exacerbation in mice with allergic airways disease.

Methods

Eight week-old wild type or IL-4 receptor knockout (IL-4R KO) mice were sensitized and challenged with OVA and inoculated with RV1B or sham HeLa cell lysate.

Results

In contrast to OVA-treated wild-type mice with both neutrophilic and eosinophilic airway inflammation, OVA-treated IL-4R KO mice showed increased neutrophilic inflammation with few eosinophils in the airways. Like wild-type mice, IL-4R KO mice showed OVA-induced airway hyperreactivity which was further exacerbated by RV. There was a shift in lung cytokines from a type 2-predominant response to a type 1 response, including production of IL-12p40 and TNF-α. IL-17A was also increased. RV infection of OVA-treated IL-4R KO mice further increased neutrophilic inflammation. Bronchoalveolar macrophages showed an M1 polarization pattern and ex vivo RV infection increased macrophage production of TNF-α, IFN-γ and IL-12p40. Finally, lung cells from OVA-treated IL-4R KO mice showed reduced CD206+ CD301+ M2 macrophages, decreased IL-13 and increased TNF-α and IL-17A production by F4/80+, CD11b+ macrophages.

Conclusions

OVA-treated IL-4R KO mice show neutrophilic airway inflammation constituting a model of allergic, type 1 cytokine-driven neutrophilic asthma. In the absence of IL-4/IL-13 signaling, RV infection of OVA-treated mice increased type 1 cytokine and IL-17A production from conventionally-activated macrophages, augmenting neutrophilic rather than eosinophilic inflammation. In mice with allergic airways inflammation, IL-4R signaling determines macrophage activation state and the response to subsequent RV infection.

IL-17A mediates a selective gene expression profile in asthmatic human airway smooth muscle cells

Airway smooth muscle (ASM) cells are thought to contribute to the pathogenesis of allergic asthma by orchestrating and perpetuating airway inflammation and remodeling responses. In this study, we evaluated the IL-17RA signal transduction and gene expression profile in ASM cells from subjects with mild asthma and healthy individuals. Human primary ASM cells were treated with IL-17A and probed by the Affymetrix GeneChip array, and gene targets were validated by real-time quantitative RT-PCR. Genomic analysis underlined the proinflammatory nature of IL-17A, as multiple NF-κB regulatory factors and chemokines were induced in ASM cells. Transcriptional regulators consisting of primary response genes were overrepresented and displayed dynamic expression profiles. IL-17A poorly enhanced IL-1β or IL-22 gene responses in ASM cells from both subjects with mild asthma and healthy donors. Interestingly, protein modifications to the NF-κB regulatory network were not observed after IL-17A stimulation, although oscillations in IκBε expression were detected. ASM cells from subjects with mild asthma up-regulated more genes with greater overall variability in response to IL-17A than from healthy donors. Finally, in response to IL-17A, ASM cells displayed rapid activation of the extracellular signal-regulated kinase/ribosomal S6 kinase signaling pathway and increased nuclear levels of phosphorylated extracellular signal-regulated kinase. Taken together, our results suggest that IL-17A mediated modest gene expression response, which, in cooperation with the NF-κB signaling network, may regulate the gene expression profile in ASM cells.

Cytokines (interleukin-9, IL-17, IL-22, IL-25 and IL-33) and asthma

Asthma is a reversible airway obstruction that is characterized by constriction of airway smooth muscle, hyper secretion of mucus, edema and airway hyper responsiveness (AHR), mucus secretion and thickening of the basement membrane underlying the airway epithelium. During the process of airway inflammation, complex interactions of innate and adaptive immune cells as well as structural cells and their cytokines have many important roles. It was believed that airway inflammation is orchestrated by allergen specific T helper (Th) 2 cells, which recruit and accumulate in the lungs and produce a range of different effector cytokines. However, more recent studies have revealed the potential collaboration of other helper T cells and their cytokines in this process. Th17 cell may have a role in severe asthma and chronic obstructive pulmonary disease (COPD). Interleukin (IL)-9-producing subset called Th9 cell, Th22 cells which primarily secrete IL-22, IL-13 and tumor necrosis factor-α and Th25 cells via producing IL-25 are believed to be important for initiating allergic reactions and developing airway inflammation. Cytokines are important in asthma and play a critical role in orchestrating the allergic inflammatory response, although the precise role of each cytokine remains to be determined. The aim of this review is to summarize the current knowledge about the possible roles of newly identified helper T cells derived cytokines (IL-9, 17, 22, 25 and IL-33) in asthma. The potential therapeutic applications emerging from the roles of these cytokines will be discussed as well.

Pharmacologic repression of retinoic acid receptor-related orphan nuclear receptor γ is therapeutic in the collagen-induced arthritis experimental model

OBJECTIVE

The nuclear receptor retinoic acid receptor-related orphan nuclear receptor γ (RORγ; T cell-specific isoform RORγt) is a key regulator of Th17 cell differentiation, controlling the production of the inflammatory cytokine interleukin-17 (IL-17). Lipopolysaccharide (LPS) stimulation of monocytes leads to the induction of RORγ. We previously showed that the potent and selective inverse agonist of RORγ, SR2211, was effective at suppressing IL-17 production in EL4 cells. The aim of this study was to examine the effects of SR2211 treatment on proinflammatory cytokine expression in LPS-stimulated RAW 264.7 cells as well as on joint inflammation in vivo in mice with collagen-induced arthritis (CIA).

METHODS

Collagen was injected into the tail of DBA mice, followed by a booster inoculation 21 days later. Three days prior to the booster inoculation, SR2211 was administered twice daily for 15 days. Thymus, spleen, and draining lymph nodes (DLNs) were then harvested, and Th17 cell differentiation and DLN stimulation were performed.

RESULTS

Treatment of Th17 cells with SR2211 suppressed the expression and production of inflammatory cytokines. Likewise, SR2211 reduced inflammatory cytokine production in LPS-stimulated RAW 264.7 cells. Mice with CIA that received SR2211 twice daily for 15 days exhibited a statistically significant reduction in joint inflammation as compared to mice that received only vehicle. Interestingly, systemic Th1 cell activation was detected in SR2211-treated mice with CIA, as indicated by an increase in interferon-γ levels.

CONCLUSION

The findings of this study support the idea of targeting RORγ to therapeutically repress inflammatory T cell function and macrophage activation in humans with rheumatoid arthritis. Compounds such as SR2211 have potential utility for the treatment of inflammatory disease.

Perinatal Immunization With Vaccine-Grade Listeria monocytogenes Provides Protection Against Murine Th2 Airway Inflammation

Purpose

Asthma is a chronic respiratory disorder that leads to inflammation and narrowing of the airways. Its global prevalence has attained epidemic levels and treatment options that reach beyond temporary relief of symptoms are urgently needed. Since the processes leading to clinically symptomatic asthma start early in life, we set out to systematically evaluate a neonatal immunotherapeutic based on Listeria monocytogenes (Lm) for the control of allergic sensitization.

Methods

We modified Lm to express the model allergen, ovalbumin (OVA), and tested the ability of neonatal immunization with this strain to control allergic sensitization in a mouse model of OVA-induced asthma. Mice were immunized as newborns with live or heat killed LmOVA or live Lm, followed 6 weeks later by allergic sensitization with OVA. In order to determine whether the T_H1-polarizing effect of this vaccine vector inadvertently may exacerbate development of certain T_H1-driven allergic diseases, mice immunized as newborns were assessed in a model of adult hypersensitivity pneumonitis (HP).

Results

Both LmOVA and Lm-control vaccines were highly effective in providing long-lasting protection from airway inflammation after only one immunization given perinatally. Serum antibody levels and lung cytokine production suggest that this prophylactic strategy is associated with an allergen specific T_H1-dominated response. Specifically, LmOVA vaccinated mice displayed significantly elevated OVA-specific serum IgG2a, but no difference in anti-OVA IgE antibodies and only slightly decreased anti-OVA IgG1 antibodies. Importantly, Lm-based neonatal vaccination did not exacerbate Th1/Th17 driven HP, arguing against broad spectrum immune skewing.

Conclusions

Our findings highlight the promise of early life Lm-based immunomodulatory interventions as a prophylactic strategy for allergic asthma.

IKKβ in intestinal epithelial cells regulates allergen-specific IgA and allergic inflammation at distant mucosal sites

Regulation of allergic responses by intestinal epithelial cells (IECs) remains poorly understood. Using a model of oral allergen sensitization in the presence of cholera toxin as adjuvant and mice with cell-specific deletion of inhibitor-κB kinase (IKKβ) in IECs (IKKβ(ΔIEC)), we addressed the contribution of IECs to allergic sensitization to ingested antigens and allergic manifestations at distant mucosal site of the airways. Cholera toxin induced higher pro-inflammatory responses and altered the profile of the gut microbiota in IKKβ(ΔIEC) mice. Antigen-specific immunoglobulin E (IgE) responses were unaltered in IKKβ(ΔIEC) mice, but their IgA antibodies (Abs), T helper type 1 (Th1) and Th17 responses were enhanced. Upon nasal antigen challenge, these mice developed lower levels of allergic lung inflammation, which correlated with higher levels of IgA Abs in the airways. The IKKβ(ΔIEC) mice also recruited a higher number of gut-sensitized T cells in the airways after nasal antigen challenge and developed airway hyper-responsiveness, which were suppressed by treatment with anti-interleukin-17A. Fecal microbiota transplant during allergic sensitization reduced Th17 responses in IKKβ(ΔIEC) mice, but did not affect IgA Ab responses. In summary, we show that IKKβ in IECs shapes the gut microbiota and immune responses to ingested antigens and influences allergic responses in the airways via regulation of IgA Ab responses.

A tale of two cytokines: IL-17 and IL-22 in asthma and infection

The Th17 pathway has recently been shown to play a critical role in host defense, allergic responses and autoimmune inflammation. Th17 cells predominantly produce IL-17 and IL-22, which are two cytokines with broad effects in the lung and other tissues. This review summarizes not only what is currently known about the molecular regulation of this pathway and Th17-related cytokine signaling, but also the roles of these cytokines in pathogen immunity and asthma. In the last 5 years, the Th17 field has rapidly grown and research has revealed that the Th17 pathway is essential in lung pathogenesis in response to exogenous stimuli. As work in the field continues, it is expected that many exciting therapeutic advances will be made for a broad range of diseases.

Galectin-9 ameliorates anti-GBM glomerulonephritis by inhibiting Th1 and Th17 immune responses in mice

Antiglomerular basement membrane glomerulonephritis (anti-GBM GN) is a Th1- and Th17-predominant autoimmune disease. Galectin-9 (Gal-9), identified as the ligand of Tim-3, functions in diverse biological processes and leads to the apoptosis of CD4(+)Tim-3(+) T cells. It is still unclear how Gal-9 regulates the functions of Th1 and Th17 cells and prevents renal injury in anti-GBM GN. In this study, Gal-9 was administered to anti-GBM GN mice for 7 days. We found that Gal-9 retarded the increase of Scr, ameliorated renal tubular injury, and reduced the formation of crescents. The infiltration of Th1 and Th17 cells into the spleen and kidneys significantly decreased in Gal-9-treated nephritic mice. The reduced infiltration of Th1 and Th17 cells might be associated with the downregulation of CCL-20, CXCL-9, and CXCL-10 mRNAs in the kidney. In parallel, the blood levels of IFN-γ and IL-17A declined in Gal-9-treated nephritic mice at days 21 and 28. In addition, an enhanced Th2 cell-mediated immune response was observed in the kidneys of nephritic mice after a 7-day injection of Gal-9. In conclusion, the protective role of Gal-9 in anti-GBM GN is associated with the inhibition of Th1 and Th17 cell-mediated immune responses and enhanced Th2 immunity in the kidney.

Vitamin D supplementation reduces airway hyperresponsiveness and allergic airway inflammation in a murine model

BACKGROUND

Asthma is a chronic disease associated with airway hyperresponsiveness (AHR), airway obstruction and airway remodelling. NF-κB is a transcriptional factor that regulates and co-ordinates the expression of various inflammatory genes. The NF-κB subunits, p50 and Rel-A, are translocated to the nucleus by importin α3 and importin α4. There is growing evidence that vitamin D is a potent immunomodulator. However, the evidence for beneficial or adverse effects of vitamin D in asthma is still unclear.

OBJECTIVE

In this study, we examined the effect of vitamin D status on AHR, airway inflammation and cytokines in the bronchoalveolar lavage fluid (BALF) in a murine model of allergic asthma.

METHODS

Female BALB/c mice were fed with special vitamin D-deficient or vitamin D-sufficient (2000 IU/kg) or vitamin D-supplemented (10,000 IU/kg) diet for 13 weeks. Mice were sensitized and challenged with ovalbumin (OVA). The effect of vitamin D on lung histology, AHR, T regulatory cells (Tregs) and BALF cytokines was examined. The expression of importin-α3 and Rel-A in the lung of OVA-sensitized mice was analysed using immunofluorescence.

RESULTS

Vitamin D deficiency was associated with higher AHR in OVA-sensitized and challenged mice than those in vitamin D-sufficient mice. This was accompanied with marked signs of airway remodelling, high BALF eosinophilia, increased BALF pro-inflammatory cytokines, reduced BALF IL-10 levels, reduced blood Tregs, increased expression of importin-α3 and Rel-A in the lung tissue. Vitamin D supplementation attenuated the pro-inflammatory effects, but did not completely reverse the features of allergic airway inflammation.

CONCLUSION AND CLINICAL RELEVANCE

Vitamin D could be beneficial as an adjunct therapy in the treatment of allergic asthma.

RORs in autoimmune disease

The retinoic acid receptor-related orphan receptor (ROR) subfamily of nuclear receptors are transcription factors involved in the maintenance of circadian rhythm and are essential for proper immune function. The T cell-specific isoform, RORγt, is required for T helper 17 cells (TH17) development and it has been implicated in the pathogenesis of autoimmune diseases including multiple sclerosis and rheumatoid arthritis. Thus, pharmacological repression of RORγt may provide a strategy for therapeutic intervention in autoimmune disorders. This chapter provides a summary of the current status for target validation and development of new chemical entities targeting RORγt.

Molecular pathology of macrophages and interleukin-17 in age-related macular degeneration

The pathology of age-related macular degeneration (AMD) is characterized by degeneration of photoreceptors and retinal pigment epithelial cells as well as by changes of choroidal capillaries in the macula. Although AMD is not a typical uveitis, there is a consistence and an imbalance of ocular para-inflammation. Ocular inflammation, particularly in the macula, plays a critical role in AMD pathogenesis. The inflammatory and immune-related elements involved in AMD include inflammatory and related cells as well as the secreted molecules and factors from these cells. Innate immune system elements such as macrophages and cytokines play an important role in AMD pathology and pathogenesis. This chapter reviews the observed deviation in macrophage plasticity and the elevated expression of interleukin-17 in AMD eyes while discussing potential contributions to AMD pathogenesis. Targeting of these specific inflammatory pathways and molecules at appropriate times should be explored and may become promising novel adjunct agents to AMD therapy.

Th17 cells and tissue remodeling in atopic and contact dermatitis

BACKGROUND

Eczematous skin lesions of atopic dermatitis (AD) as well as allergic and irritant contact dermatitis (ACD, ICD) are characterized by the same typical clinical signs, although due to different causes. In both AD and ACD, the presence of T helper 17 cells which play an important role in host defense, has been reported. Furthermore, IL-17 is involved in tissue repair and remodeling. This study aimed to investigate IL-17 expression in acute eczematous skin lesions and correlate it with markers of remodeling in AD, ACD, and ICD.

METHODS

Skin specimens were taken from positive patch test reactions to aeroallergens, contact allergens, and irritants at days 2, 3, and 4. Inflammatory cells as well as the expression of cytokines and extracellular matrix proteins were evaluated by immunofluorescence staining and confocal microscopy.

RESULTS

Allergic contact dermatitis and ICD were characterized by IFN-γ expression, whereas in AD lesions, IL-13 expression and high numbers of eosinophils were the prominent phenotype. Expression of IL-17, but also IL-21 and IL-22, was observed in all eczema subtypes. The number of IL-22+ T cells correlated with the number of eosinophils. Markers of remodeling such as MMP-9, procollagen-3, and tenascin C were observed in all acute eczematous lesions, while a correlation of IL-17+ T cell numbers with tenascin C-expressing cells and MMP-9+ eosinophils was apparent.

CONCLUSION

The expression of IL-17 and related cytokines, such as IL-22, was demonstrated in acute eczematous lesions independent of their pathogenesis. Our results suggest a potential role for IL-17 in remodeling of the skin.

Hyaluronic acid graft polymers displaying peptide antigen modulate dendritic cell response in vitro

A novel oxime grafting scheme was utilized to conjugate an ICAM-1 ligand (LABL), a cellular antigen ovalbumin (OVA), or both peptides simultaneously to hyaluronic acid (HA). Samples of HA only and the various peptide grafted HA were found to bind to dendritic cells (DCs). HA with grafted LABL and OVA showed the greatest binding to DCs. Dendritic cells treated with HA, HA with grafted LABL, or HA with grafted LABL and OVA significantly suppressed T cell and DC conjugate formation and T cell proliferation and reduced proinflammatory cytokine production compared to untreated cells. These results suggest that HA serves as an effective backbone for multivalent ligand presentation for inhibiting T cell response to antigen presentation. In addition, multivalent display of both antigen and an ICAM-1 inhibitor (LABL) may enhance binding to DCs and could potentially disrupt cellular signaling leading to autoimmunity.

Zinc oxide nanoparticles provide an adjuvant effect to ovalbumin via a Th2 response in Balb/c mice

Zinc oxide nanoparticles (ZNPs) have been used in dietary supplements and may cause an immunomodulatory effect. The present study investigated the effect of ZNPs on antigen-specific immune responses in mice sensitized with the T-cell-dependent antigen ovalbumin (OVA). BALB/c mice were intraperitoneally administered ZNPs (0.25, 0.5, 1 and 3mg) once, in combination with OVA, and the serum antibodies, splenocyte reactivity and activation of antigen-presenting cells were examined. The serum levels of OVA-specific IgG1 and IgE were found significantly enhanced by treatment with ZNPs over control. An increased level of IL-2, IL-4, IL-6, IL-17 and decreased level of IL-10 and TNF-α in splenocytes administered with ZNPs were observed in comparison with control. The ZNPs and OVA-stimulated T lymphocytes showed enhanced proliferation compared with control. Macrophages and B cells showed high expression of MHC class II, whereas higher expression of CD11b in macrophages of the ZNPs and ZNPs/OVA treated groups was observed. The lungs and spleen had increased eosinophils and mast cell numbers. Also, myeloperoxidase activity in lungs was found to be increased by 2.5-fold in the case of ZNPs and 3.75-fold increase in ZNPs/OVA, whereas in intestine, there was significant increase in both the groups. Increased expression of the genes for GATA-3, SOCS-3, TLR-4, IL-13 and IL-5 in the intestine was observed. Collectively, these data indicate that systemic exposure to a single administration of ZNPs could enhance subsequent antigen-specific immune reactions, including the serum production of antigen-specific antibodies, and the functionality of T cells.

Local IL-17A potentiates early neutrophil recruitment to the respiratory tract during severe RSV infection

Respiratory syncytial virus (RSV) bronchiolitis triggers a strong innate immune response characterized by excessive neutrophil infiltration which contributes to RSV induced pathology. The cytokine IL-17A enhances neutrophil infiltration into virus infected lungs. IL-17A is however best known as an effector of adaptive immune responses. The role of IL-17A in early immune modulation in RSV infection is unknown. We aimed to elucidate whether local IL-17A facilitates the innate neutrophil infiltration into RSV infected lungs prior to adaptive immunity. To this end, we studied IL-17A production in newborns that were hospitalized for severe RSV bronchiolitis. In tracheal aspirates we measured IL-17A concentration and neutrophil counts. We utilized cultured human epithelial cells to test if IL-17A regulates RSV infection-induced IL-8 release as mediator of neutrophil recruitment. In mice we investigated the cell types that are responsible for early innate IL-17A production during RSV infection. Using IL-17A neutralizing antibodies we tested if IL-17A is responsible for innate neutrophil infiltration in mice. Our data show that increased IL-17A production in newborn RSV patient lungs correlates with subsequent neutrophil counts recruited to the lungs. IL-17A potentiates RSV-induced production of the neutrophil-attracting chemokine IL-8 by airway epithelial cells in vitro. Various lung-resident lymphocytes produced IL-17A during early RSV infection in Balb/c mice, of which a local population of CD4 T cells stood out as the predominant RSV-induced cell type. By removing IL-17A during early RSV infection in mice we showed that IL-17A is responsible for enhanced innate neutrophil infiltration in vivo. Using patient material, in vitro studies, and an animal model of RSV infection, we thus show that early local IL-17A production in the airways during RSV bronchiolitis facilitates neutrophil recruitment with pathologic consequences to infant lungs.

Th17 cell plays a role in the pathogenesis of Hashimoto's thyroiditis in patients

Hashimoto's thyroiditis (HT) has long been epidemiologically associated with excess iodine levels. However, the underlying immunological mechanisms still remain largely unexplored. Th17 cells are commonly recognized as playing vital roles in various autoimmune diseases. Here we show that intra-thyroid infiltrating Th17 cells and serum IL-17 levels were significantly increased in HT patients. However, the concentration of serum IL-17 was inversely correlated with patients' residual thyroid function while the heterogeneously expressed thyroid IL-17 was directly correlated with local fibrosis. Administration of moderate high levels of iodine was found to facilitate the polarization of murine splenic naïve T cells into Th17 cells, whereas extreme high levels of iodine favored Th1 polarization and inhibited Treg development. These findings suggest that both Th1 and Th17 cells may be involved in the pathogenesis of HT and high levels of iodine may play a critical role in this process by modulating T cell differentiation.

IL-23 protection against Plasmodium berghei infection in mice is partially dependent on IL-17 from macrophages

Although IL-12 is believed to contribute to protective immune responses, the role played by IL-23 (a member of the IL-12 family) in malaria is elusive. Here, we show that IL-23 is produced during infection with Plasmodium berghei NK65. Mice deficient in IL-23 (p19KO) had higher parasitemia and died earlier than wild-type (WT) controls. Interestingly, p19KO mice had lower numbers of IL-17-producing splenic cells than their WT counterparts. Furthermore, mice deficient in IL-17 (17KO) suffered higher parasitemia than the WT controls, indicating that IL-23-mediated protection is dependent on induction of IL-17 during infection. We found that macrophages were responsible for IL-17 production in response to IL-23. We observed a striking reduction in splenic macrophages in the p19KO and 17KO mice, both of which became highly susceptible to infection. Thus, IL-17 appears to be crucial for maintenance of splenic macrophages. Adoptive transfer of macrophages into macrophage-depleted mice confirmed that macrophage-derived IL-17 is required for macrophage accumulation and parasite eradication in the recipient mice. We also found that IL-17 induces CCL2/7, which recruit macrophages. Our findings reveal a novel protective mechanism whereby IL-23, IL-17, and macrophages reduce the severity of infection with blood-stage malaria parasites.

Pivotal roles of T-helper 17-related cytokines, IL-17, IL-22, and IL-23, in inflammatory diseases

T-helper 17 (Th17) cells are characterized by producing interleukin-17 (IL-17, also called IL-17A), IL-17F, IL-21, and IL-22 and potentially TNF- α and IL-6 upon certain stimulation. IL-23, which promotes Th17 cell development, as well as IL-17 and IL-22 produced by the Th17 cells plays essential roles in various inflammatory diseases, such as experimental autoimmune encephalomyelitis, rheumatoid arthritis, colitis, and Concanavalin A-induced hepatitis. In this review, we summarize the characteristics of the functional role of Th17 cells, with particular focus on the Th17 cell-related cytokines such as IL-17, IL-22, and IL-23, in mouse models and human inflammatory diseases.

IL-17-producing peripheral blood CD177+ neutrophils increase in allergic asthmatic subjects

Background

A T helper cell (T_H) 17-biased response has been observed in patients with allergic asthma, particularly in those with neutrophil accumulation in the lung. Therefore, we sought to test the hypothesis that neutrophils might be an important source of interleukin (IL)-17 in allergic asthma.

Methods

Whole peripheral blood cells from non-asthmatic control subjects (n = 17) and patients with mild asthma (n = 7), moderate but persistent asthma (n = 4), or acute asthma (n = 6) were analyzed for IL-17A expression in CD177⁺ neutrophils. IL-17A expression was also analyzed in CD3⁺CD4⁺ and CD3⁺CD8⁺ lymphocyte populations. Asthmatic patients were classified as allergic to fungi, indoor allergens, or other allergens (e.g., pollen) based on a positive intradermal allergy test reaction.

Results

The percentage of CD177⁺ neutrophils in whole blood of asthmatic patients was higher than in healthy controls and highest in the moderate asthma group. Furthermore, the percentage of CD177⁺IL-17⁺ neutrophils was elevated in patients with mild asthma, whereas the CD4⁺ IL-17⁺ lymphocyte population was higher in asthmatic patients and highest in those with moderate but persistent asthma. We also found that the four patients that were allergic to fungi had the highest percentage of CD177⁺IL17⁺ neutrophils and CD8⁺IL17⁺ lymphocytes.

Conclusion

IL17⁺CD177⁺ Neutrophils increase in allergic asthma patients especially when allergic to fungi. This cell population, through release of IL-17, might be contributing during the initial phase asthmatic disease and/or during disease progression but its role has not yet been established.

Interleukin-33 and alveolar macrophages contribute to the mechanisms underlying the exacerbation of IgE-mediated airway inflammation and remodelling in mice

Allergen-specific IgE has long been regarded as a major molecular component of allergic asthma. Additionally, there is increasing evidence of the important roles of interleukin-33 (IL-33) in the disease. Here, we show that IL-33 and alveolar macrophages play essential roles in the exacerbation of IgE-mediated airway inflammation and remodelling. BALB/c mice passively sensitized with ovalbumin (OVA)-specific IgE monoclonal antibody (mAb) were challenged with OVA seven times intratracheally. The seventh challenge exacerbated airway inflammation and remodelling compared with the fourth challenge; furthermore, markedly increased expression of IL-33 in the lungs was observed at the fourth and seventh challenges. When anti-IL-33 or anti-ST2 antibody was administered during the fourth to seventh challenge, airway inflammation and remodelling were significantly inhibited at the seventh challenge. Because increases of IL-33(+) and ST2(+) alveolar macrophages and ST2(+)  CD4(+) T cells in the lungs were observed at the fourth challenge, the roles of macrophages and CD4(+) cells were investigated. Depletion of macrophages by 2-chloroadenosine during the fourth to seventh challenge suppressed airway inflammation and remodelling, and IL-33 production in the lung at the seventh challenge; additionally, anti-CD4 mAb inhibited airway inflammation, but not airway remodelling and IL-33 production. Meanwhile, treatment with 2-chloroadenosine or anti-CD4 mAb decreased IL-33-induced airway inflammation in normal mice; airway remodelling was repressed only by 2-chloroadenosine. These results illustrate that macrophage-derived IL-33 contributes to the exacerbation of IgE-mediated airway inflammation by mechanisms associated with macrophages and CD4(+) cells, and airway remodelling through the activation of macrophages.

Interleukin-1 receptor and caspase-1 are required for the Th17 response in nitrogen dioxide-promoted allergic airway disease

Nitrogen dioxide (NO2) is an environmental pollutant and endogenously generated oxidant associated with the development, severity, and exacerbation of asthma. NO2 exposure is capable of allergically sensitizing mice to the innocuous inhaled antigen ovalbumin (OVA), promoting neutrophil and eosinophil recruitment, and a mixed Th2/Th17 response upon antigen challenge that is reminiscent of severe asthma. However, the identity of IL-17A-producing cells and the mechanisms governing their ontogeny in NO2-promoted allergic airway disease remain unstudied. We measured the kinetics of lung inflammation after antigen challenge in NO2-promoted allergic airway disease, including inflammatory cells in bronchoalveolar lavage and antigen-specific IL-17A production from the lung. We determined that IL-17A(+) cells were predominately CD4(+)T cell receptor (TCR)β(+) Th17 cells, and that a functional IL-1 receptor was required for Th17, but not Th2, cytokine production after in vitro antigen restimulation of lung cells. The absence of natural killer T cells, γδ T cells, or the inflammasome scaffold nucleotide-binding oligomerization domain, leucine rich repeat and pyrin domain (Nlrp)3 did not affect the development of NO2-promoted allergic inflammation or IL-17A production. Similarly, neutrophil depletion or the neutralization of IL-1α during sensitization exerted no effect on these parameters. However, the absence of caspase-1 significantly reduced IL-17A production from lung cells without affecting Th2 cytokines or lung inflammation. Finally, the intranasal administration of IL-1β and the inhalation of antigen promoted allergic sensitization that was reflected by neutrophilic airway inflammation and IL-17A production from CD4(+)TCRβ(+) Th17 cells subsequent to antigen challenge. These data implicate a role for caspase-1 and IL-1β in the IL-1 receptor-dependent Th17 response manifest in NO2-promoted allergic airway disease.

Intra-amniotic IL-1β induces fetal inflammation in rhesus monkeys and alters the regulatory T cell/IL-17 balance

Very low birth weight preterm newborns are susceptible to the development of debilitating inflammatory diseases, many of which are associated with chorioamnionitis. To define the effects of chorioamnionitis on the fetal immune system, IL-1β was administered intra-amniotically at ~80% gestation in rhesus monkeys. IL-1β caused histological chorioamnionitis, as well as lung inflammation (infiltration of neutrophils or monocytes in the fetal airways). There were large increases in multiple proinflammatory cytokine mRNAs in the lungs at 24 h postadministration, which remained elevated relative to controls at 72 h. Intra-amniotic IL-1β also induced the sustained expression of the surfactant proteins in the lungs. Importantly, IL-1β significantly altered the balance between inflammatory and regulatory T cells. Twenty-four hours after IL-1β injection, the frequency of CD3(+)CD4(+)FOXP3(+) T cells was decreased in lymphoid organs. In contrast, IL-17A-producing cells (CD3(+)CD4(+), CD3(+)CD4(-), and CD3(-)CD4(-) subsets) were increased in lymphoid organs. The frequency of IFN-γ-expressing cells did not change. In this model of a single exposure to an inflammatory trigger, CD3(+)CD4(+)FOXP3(+) cells rebounded quickly, and their frequency was increased at 72 h compared with controls. IL-17 expression was also transient. Interestingly, the T cell profile alteration was confined to the lymphoid organs and not to circulating fetal T cells. Together, these results suggest that the chorioamnionitis-induced IL-1/IL-17 axis is involved in the severe inflammation that can develop in preterm newborns. Boosting regulatory T cells and/or controlling IL-17 may provide a means to ameliorate these abnormalities.

Ovariectomized OVA-sensitized mice display increased frequency of CD4(+)Foxp3(+) T regulatory cells in the periphery

It is well established that female sex hormones have a pivotal role in inflammation. For instance, our group has previously reported that estradiol has proinflammatory actions during allergic lung response in animal models. Based on these findings, we have decided to further investigate whether T regulatory cells are affected by female sex hormones absence after ovariectomy. We evaluated by flow cytometry the frequencies of CD4⁺Foxp3⁺ T regulatory cells (Tregs) in central and peripheral lymphoid organs, such as the thymus, spleen and lymph nodes. Moreover, we have also used the murine model of allergic lung inflammation a to evaluate how female sex hormones would affect the immune response in vivo. To address that, ovariectomized or sham operated female Balb/c mice were sensitized or not with ovalbumin 7 and 14 days later and subsequently challenged twice by aerosolized ovalbumin on day 21. Besides the frequency of CD4⁺Foxp3⁺ T regulatory cells, we also measured the cytokines IL-4, IL-5, IL-10, IL-13 and IL-17 in the bronchoalveolar lavage from lungs of ovalbumine challenged groups. Our results demonstrate that the absence of female sex hormones after ovariectomy is able to increase the frequency of Tregs in the periphery. As we did not observe differences in the thymus-derived natural occurring Tregs, our data may indicate expansion or conversion of peripheral adaptive Tregs. In accordance with Treg suppressive activity, ovariectomized and ovalbumine-sensitized and challenged animals had significantly reduced lung inflammation. This was observed after cytokine analysis of lung explants showing significant reduction of pro-inflammatory cytokines, such as IL-4, IL-5, IL-13 and IL-17, associated to increased amount of IL-10. In summary, our data clearly demonstrates that OVA sensitization 7 days after ovariectomy culminates in reduced lung inflammation, which may be directly correlated with the expansion of Tregs in the periphery and further higher IL-10 secretion in the lungs.

The role of IL-33 in gut mucosal inflammation

Interleukin (IL)-33 is a recently identified cytokine belonging to the IL-1 family that is widely expressed throughout the body and has the ability to induce Th2 immune responses. In addition, IL-33 plays a key role in promoting host defenses against parasites through the expansion of a novel population of innate lymphoid cells. In recent years, a growing body of evidence has shown that the proinflammatory properties displayed by IL-33 are detrimental in several experimental models of inflammation; in others, however, IL-33 appears to have protective functions. In 2010, four different research groups consistently described the upregulation of IL-33 in patients with inflammatory bowel disease (IBD). Animal models of IBD were subsequently utilized in order to mechanistically determine the precise role of IL-33 in chronic intestinal inflammation, without, however, reaching conclusive evidence demonstrating whether IL-33 is pathogenic or protective. Indeed, data generated from these studies suggest that IL-33 may possess dichotomous functions, enhancing inflammatory responses on one hand and promoting epithelial integrity on the other. This review focuses on the available data regarding IL-33/ST2 in the physiological and inflammatory states of the gut in order to speculate on the possible roles of this novel IL-1 family member in intestinal inflammation.

IL-17C is a mediator of respiratory epithelial innate immune response

The IL-17 family of cytokines consists of at least six members (IL-17A to -F). IL-17 directly activates epithelial cells leading to the expression of inflammatory mediators and antimicrobial factors. Recent studies showed that IL-17C is expressed by epithelial cells. It was the purpose of this study to examine the expression of IL-17 family members in respiratory epithelial cells during bacterial infection. We show that common bacterial pathogens, such as Pseudomonas aeruginosa and Haemophilus influenzae, and ligands of Toll-like receptors 3 and 5 (flagellin, polyI:C) induced the expression and release of IL-17C in cultured human bronchial epithelial cells (HBECs). The expression of IL-17A, -B, -D, or -E was not induced by bacterial stimuli in HBECs. IL-17C enhanced inflammatory responses of respiratory epithelial cells infected with P. aeruginosa. Furthermore, we demonstrate that cigarette smoke suppressed the expression of IL-17C in HBECs in response to bacterial infection and in vivo in the upper airways of mice colonized with H. influenzae. IL-17C could also be detected in bronchial tissue of subjects with infection-related lung diseases. These data show that IL-17C is involved in the innate immune response of respiratory epithelial cells and is suppressed by cigarette smoke.

IL-17-mediated M1/M2 macrophage alteration contributes to pathogenesis of bisphosphonate-related osteonecrosis of the jaws

PURPOSE

Osteonecrosis of the jaw (ONJ) is emerging as one of the important complications in cancer patients treated with antiresorptive agents. This study explored the potential role of interleukin (IL)-17-mediated M1/M2 macrophage alterations in the pathogenesis of bisphosphonate-related osteonecrosis of the jaw (BRONJ).

EXPERIMENTAL DESIGN

The expression of IL-17 and M1 and M2 macrophage markers at the local mucosal site of human BRONJ lesions was examined by immunofluorescence studies. BRONJ-like disease was induced in C57BL/6 mice and multiple myeloma-burdened mice by intravenous injection of zoledronate to evaluate the correlation of elevated IL-17 levels with changes in M1 and M2 macrophage phenotypes and the therapeutic effects of blocking IL-17 on pathogenesis of BRONJ-like disease.

RESULTS

Increased T-helper (TH)17 cells and IL-17 cytokine correlate with an increase in M1/M2 macrophages ratio at the local mucosal site of both murine and human BRONJ lesion. Convincingly, in mice burdened with multiple myeloma, a combination of elevated suprabasal level and drug-induced IL-17 activity augmented the incidence of BRONJ; both systemic increase of IL-17 and disease severity could be reversed by adoptive transfer of ex vivo expanded M2 macrophages. Targeting IL-17 via specific neutralizing antibodies or a small inhibitory molecule, laquinimod, significantly decreased M1/M2 ratio and concomitantly suppressed BRONJ-like condition in mice. Mechanistically, IL-17 enhanced IFN-γ-induced M1 polarization through augmenting STAT-1 phosphorylation while suppressing IL-4-mediated M2 conversion via inhibiting STAT-6 activation.

CONCLUSIONS

These findings have established a compelling linkage between activated IL-17-mediated polarization of M1 macrophages and the development of BRONJ-like conditions in both human disease and murine models.

Use of folate-conjugated imaging agents to target alternatively activated macrophages in a murine model of asthma

Pro-inflammatory macrophages play a prominent role in such autoimmune diseases as rheumatoid arthritis, Crohn's disease, psoriasis, sarcoidosis, and atherosclerosis. Because pro-inflammatory macrophages have also been shown to overexpress a receptor for the vitamin folic acid (i.e., folate receptor beta; FR-β), folate-linked drugs have been explored for use in imaging and treatment of these same diseases. To determine whether allergic inflammatory disorders might be similarly targeted with folate-linked drugs, we have examined the characteristics of macrophages that are prominent in the pathogenesis of asthma. We report here that macrophages from the lungs of mice with experimental allergic asthma express FR-β. We further document that these FR-β(+) macrophages coexpress markers of alternatively activated (M2-type) macrophages, including the mannose receptor and arginase-1. Finally, we demonstrate that folate-conjugated fluorescent dyes and radioimaging agents can be specifically targeted to these asthmatic lung macrophages, with little uptake by macrophages present in healthy lung tissue. These data suggest strategies for the development of novel diagnostic agents for the imaging of asthma and other diseases involving alternatively activated macrophages.

Prior oral exposure to environmental immunosuppressive chemicals methoxychlor, parathion, or piperonyl butoxide aggravates allergic airway inflammation in NC/Nga mice

BACKGROUND

Immunosuppressive environmental chemicals may increase the potency of allergens and thereby play a role in the development of respiratory tract allergies, such as allergic rhinitis and asthma.

OBJECTIVES

We investigated the association between environmental immunosuppressive chemicals and the allergic airway inflammation development.

METHODS

We used a mouse model of ovalbumin (OVA)-induced allergic airway inflammation. NC/Nga mice were exposed orally to pesticides parathion (an organophosphate compound) or methoxychlor (an organochlorine compound), or to an insecticide synergist piperonyl butoxide, prior to OVA intraperitoneal sensitization and inhalation challenge. We assessed serum IgE levels, B-cell counts, cytokine production, IgE production in hilar lymph nodes, eosinophil counts, chemokine levels in bronchoalveolar lavage fluid, and cytokine gene expression in the lung.

RESULTS

Exposure to environmental immunosuppressive chemicals markedly increased serum IgE - IgE-positive B-cells, IgE and cytokines in lymph nodes - eosinophils and chemokines in BALF - IL-10a and IL-17 in the lung.

CONCLUSIONS

Allergic airway inflammation can be aggravated by prior exposure to immunosuppressive environmental chemicals.

Anti-inflammatory and immune-modulating effect of Ulmus davidiana var. japonica Nakai extract on a macrophage cell line and immune cells in the mouse small intestine

ETHNOPHARMACOLOGICAL RELEVANCE

Traditional Oriental medicine has utilized the barks of the stem and root of Ulmus davidiana var. japonica Nakai (UD) to treat inflammatory disorders.

AIM OF THE STUDY

The purpose of the present study was to evaluate UD's anti-inflammatory and immune-modulating effects on a lipopolysaccharide (LPS)-stimulated macrophage cell line and small-intestinal lamina propria (LP) cells, respectively.

MATERIALS AND METHODS

RAW 264.7 cells were stimulated with LPS in the presence of various concentrations of a UD water-soluble extract. Cell viability, nitric oxide (NO) production, and the level of inflammatory cytokines synthesis were measured. Among the mice receiving the UD water-soluble extract, changes in the LP cell populations and immunoglobulin (Ig)A production were evaluated.

RESULTS

The UD water-soluble extract inhibited LPS-induced NO synthesis and inflammatory cytokine production in a RAW264.7 macrophage-like cell line. Small-intestinal LP cells isolated from mice that received the UD extract displayed a decrease in the side scatter of medium-to-high cells. Those LP cells isolated from the UD-treated mice also showed a marked decrease of intracellular IgA. However, UD administration had no apparent effect on the synthesis of systemic inflammatory cytokines.

CONCLUSIONS

These results suggest that UD water-soluble extracts have anti-inflammatory properties and, as such, can be used to promote intestinal immune-homeostatic conditions.

Enhanced acute immune response in IL-12p35-/- mice is followed by accelerated distinct repair mechanisms in Staphylococcus aureus-induced murine brain abscess

BACKGROUND

Murine Staphylococcus aureus-mediated brain abscess comprises 2 major phases, an initial phase of cerebritis, followed by a healing phase characterized by capsule formation.

METHODS

C57BL/6 wild-type (WT) and IL-12p35(-/-) mice were intracerebrally infected with S. aureus to induce brain abscesses. Clinical disease activity and bacterial load were monitored. The cell populations that were involved, as well as their specific mediators, were analyzed by immunohistochemistry, quantitative real-time polymerase chain reaction, and flow cytometry.

RESULTS

In the acute phase, IL-12p35(-/-) mice were protected from disease. This was associated with enhanced recruitment of granulocytes, accompanied by upregulated expression of Il17a, Csf2 (which encodes granulocyte-macrophage colony-stimulating factor), Cxcl1, and Cxcl5, as well as increased expression of proinflammatory mediators, including Nos2 (which encodes inducible nitric oxide synthase), Ptgs2 (which encodes cyclooxygenase 2), and Tnf, that were primarily produced by granulocytes and activated microglia/macrophages. Furthermore, mechanisms associated with beneficial wound healing, including an accelerated formation of a fibrous capsule, were demonstrated by prominent VEGF-A production and collagen deposition driven by an earlier onset of T-helper 2 immunity in the absence of interleukin 12 (IL-12).

CONCLUSIONS

Brain abscess development is orchestrated by IL-12 at different stages of disease. Our data indicate that IL-12 has a nonprotective role in the acute phase and that IL-12 deficiency results in the accelerated formation of a protective capsule during the healing phase, which we consider crucial for early recovery from disease.

Dose-dependent effects of IL-17 on IL-13-induced airway inflammatory responses and airway hyperresponsiveness

The Th2 cytokine IL-13 regulates several aspects of the asthmatic phenotype, including airway inflammation, airway hyperresponsiveness, and mucus production. The Th17 cytokine IL-17A is also implicated in asthma and has been shown to both positively and negatively regulate Th2-dependent responses in murine models of allergic airways disease. Our objective in this study was to better understand the role of IL-17 in airway inflammation by examining how IL-17 modifies IL-13-induced airway inflammatory responses. We treated BALB/c mice intranasally with IL-13 or IL-17 alone or in combination for 8 consecutive days, after which airway hyperresponsiveness, inflammatory cell influx into the lung, and lung chemokine/cytokine expression were assessed. As expected, IL-13 increased airway inflammation and airway hyperresponsiveness. IL-13 also increased numbers of IL-17-producing CD4(+) and γδ T cells. Treating mice with a combination of IL-13 and IL-17 reduced infiltration of IL-17(+) γδ T cells, but increased the number of infiltrating eosinophils. In contrast, coadministration of IL-13 with a higher dose of IL-17 decreased all IL-13-induced inflammatory responses, including infiltration of both IL-17(+)CD4(+) and γδ T cells. To examine the inhibitory activity of IL-17-expressing γδ T cells in this model, these cells were adoptively transferred into naive recipients. Consistent with an inhibitory role for γδ T cells, IL-13-induced infiltration of eosinophils, lymphocytes, and IL-17(+)CD4(+) T cells was diminished in recipients of the γδ T cells. Collectively, our data indicate that allergic airway inflammatory responses induced by IL-13 are modulated by both the quantity and the cellular source of IL-17.

The Chinese Herbal Medicine Formula Sheng-Fei-Yu-Chuan-Tang Suppresses Th2 Responses and Increases IFN γ in Dermatophagoides pteronyssinus Induced Chronic Asthmatic Mice

Sheng-Fei-Yu-Chuan-Tang (SFYCT), a traditional Chinese medicine formula consisting of 13 medicinal plants, has been used in the treatment of asthma. This study demonstrated the immunoregulatory effect of SFYCT on chronic allergic asthma using the Dermatophagoides-pteronyssinus- (Der p-) challenged chronic asthmatic murine model. SFYCT decreased the airway hyperresponseness (AHR), pulmonary inflammatory cell infiltration, and airway remodeling in Der p mice. SFYCT treatment decreased Der p-induced total IgE and Der-p-specific IgG1 but not IgG2a/2b Ab titer in serum of Der p mice. SFYCT also decreased Th2 cytokines, IL-4, IL-5, and IL-13, but increased IFN-γ and IL-12 in the BALF of Der p mice. TGF-β1 and collagen production in the lung of mice were decreased by SFYCT. The mRNA expression of chemokine including Eotaxin, RANTES, and MCP-1 in the lung of Der p mice was decreased by SFYCT. In conclusion, the suppressed Der-p-induced airway inflammation, remodeling, and hyperresponseness in chronic asthma murine model are related to SFYCT inhibits Th2 responses, decreases chemokine expression and promotes IFN-γ and IL-12 production. SFYCT could show Der-p-induced Th2 responses to Th1 responses by increasing IFN-γ which is merit for clinical application on asthma patients.