CD4(+) T cell-dependent airway mucus production occurs in response to IL-5 expression in lung

Elevated Proportions of Circulating CXCR5+ Follicular Helper T Cells Reflect the Presence of Airway Obstruction in Asthma

Materials and Methods

Using flow cytometry, we identified and quantified Group 2 innate lymphocytes, T helper 2 cells, follicular helper T cells, and T helper 17 cells in peripheral blood samples from 49 individuals with asthma. We then conducted cross-sectional analyses to assess relationships between levels of these immune cells and lung function parameters, including the percentage predicted forced expiratory volume in 1 s (%FEV1). We also examined correlations between the proportions of immune cells and type 2 biomarkers.

Results

Proportions of CXCR5+ follicular helper T cells in human peripheral blood, as opposed to Group 2 innate lymphoid cells (ILC2) or T helper 2 cells, were significantly higher in cases with %FEV1 < 80% compared to those with %FEV1 ≥ 80%. Further, these proportions correlated negatively with %FEV1 and positively with blood eosinophil counts.

Conclusions

The proportion of circulating follicular helper T cells, but not T helper 2 cells or Group 2 innate lymphoid cells, may reflect the presence of airway obstruction caused by persistent type 2 inflammation.

B-cell-specific MhcII regulates microbiota composition in a primarily IgA-independent manner

Background

The expression of major histocompatibility complex class II (MhcII) molecules on B cells is required for the development of germinal centers (GCs) in lymphoid follicles; the primary sites for the generation of T-cell-dependent (TD) antibody responses. Peyer's patches (PPs) are secondary lymphoid tissues (SLOs) in the small intestine (SI) that give rise to high-affinity, TD antibodies (mainly immunoglobulin A (IgA)) generated against the microbiota. While several studies have demonstrated that MhcII antigen presentation by other immune cells coordinate TD IgA responses and regulate microbiota composition, whether or not B-cell-specific MhcII influences gut microbial ecology is unknown.

Methods

Here, we developed a novel Rag1 -/- adoptive co-transfer model to answer this question. In this model, Rag1 -/- mice were reconstituted with naïve CD4+ T cells and either MhcII-sufficient or MhcII-deficient naïve B cells. Subsequent to this, resulting shifts in microbiota composition was characterized via 16S rRNA gene sequencing of SI-resident and fecal bacterial communities.

Results

Results from our experiments indicate that SLO development and reconstitution of an anti-commensal TD IgA response can be induced in Rag1 -/- mice receiving T cells and MhcII-sufficient B cells, but not in mice receiving T cells and MhcII-deficient B cells. Results from our 16S experiments confirmed that adaptive immunity is a relevant host factor shaping microbial ecology in the gut, and that its impact was most pronounced on SI-resident bacterial communities.

Conclusion

Our data also clearly establishes that MhcII-mediated cognate interactions between B cells and T cells regulates this effect by maintaining species richness in the gut, which is a phenotype commonly associated with good health. Finally, contrary to expectations, our experimental results indicate that IgA was not responsible for driving any of the effects on the microbiota ascribed to the loss of B cell-specific MhcII. Collectively, results from our experiments support that MhcII-mediated antigen presentation by B cells regulates microbiota composition and promotes species richness through an IgA-independent mechanism.

Blockade of Tyrosine Kinase, LCK Leads to Reduction in Airway Inflammation through Regulation of Pulmonary Th2/Treg Balance and Oxidative Stress in Cockroach Extract-Induced Mouse Model of Allergic Asthma

Asthma is one of the most common inflammatory diseases affecting the airways. Approximately 300 million individuals suffer from asthma around the world. Allergic immune responses in the asthmatic airways are predominantly driven by Th2 cells and eosinophils. Lymphocyte-specific protein tyrosine kinase (LCK) is a non-receptor tyrosine kinase which regulates several key intracellular events through phosphorylation of its substrates. Some of the intracellular signaling pathways activated by LCK phosphorylation help in differentiation of Th2 cells which secrete allergic cytokines that amplify airway inflammation. Therefore, this investigative study was designed to determine the role of LCK in a cockroach extract (CE)-induced airway inflammation murine model of allergic asthma. Further, the effect of a pharmacological LCK inhibitor, A-770041, on allergic airway inflammation and key intracellular pathways in CD4+ T cells was assessed. Our data exhibit that there is an activation of LCK during allergic airway inflammation as depicted by increased p-LCK levels in CD4+ T cells. Activated LCK is involved in the activation of ITK, PLC-γ, GATA3, NFkB, and NFATc1. Activated LCK is also involved in the upregulation of Th2 related cytokines, such as IL-4/IL-5/IL-13 and oxidative stress, and the downregulation of Treg cells. Furthermore, utilization of LCK inhibitor causes the reduction in p-LCK, PLC-γ, GATA3, and NFATc1 as well as Th2 cytokines and oxidative stress. LCK inhibitor causes upregulation of Treg cells in allergic mice. LCK inhibitor also caused a reduction in CE-induced airway inflammation and mucus secretion. Therefore, the inhibition of LCK signaling could be a fruitful approach to adjust allergic airway inflammation through the attuning of Th2/Treg immune responses. This study could lead to the design of newer treatment options for better management of allergic inflammation in asthma.

Therapeutic potential of andrographolide-loaded nanoparticles on a murine asthma model

Corticosteroids commonly prescribed in asthma show several side-effects. Relatively non-toxic andrographolide (AG) has an anti-asthmatic potential. But its poor bioavailability and short plasma half-life constrain its efficacy. To overcome them, we encapsulated AG in nanoparticle (AGNP) and evaluated AGNP for anti-asthmatic efficacy on murine asthma model by oral/pulmonary delivery. AGNP had 5.47% drug loading with a sustained drug release in vitro. Plasma and lung pharmacokinetic data showed predominantly improved AG-bioavailability upon AGNP administered orally/by pulmonary route. Cell numbers, IL-4, IL-5, and IL-13 levels in broncho-alveolar lavage fluid and serum IgE content were reduced significantly after administration of AGNP compared to free-AG treatment. AGNP-mediated suppression of NF-κβ was predominantly more compared to free-AG. Further, pulmonary route showed better therapeutic performance. In conclusion, AGNP effectively controlled mild and severe asthma and the pulmonary administration of AGNP was more efficacious than the oral route.

Notch Signaling: Linking Embryonic Lung Development and Asthmatic Airway Remodeling

Lung development is mediated by assorted signaling proteins and orchestrated by complex mesenchymal-epithelial interactions. Notch signaling is an evolutionarily conserved cell-cell communication mechanism that exhibits a pivotal role in lung development. Notably, both aberrant expression and loss of regulation of Notch signaling are critically linked to the pathogenesis of various lung diseases, in particular, pulmonary fibrosis, lung cancer, pulmonary arterial hypertension, and asthmatic airway remodeling; implying that precise regulation of intensity and duration of Notch signaling is imperative for appropriate lung development. Moreover, evidence suggests that Notch signaling links embryonic lung development and asthmatic airway remodeling. Herein, we summarized all-recent advances associated with the mechanistic role of Notch signaling in lung development, consequences of aberrant expression or deletion of Notch signaling in linking early-impaired lung development and asthmatic airway remodeling, and all recently investigated potential therapeutic strategies to treat asthmatic airway remodeling.

Wnt/β-catenin signaling links embryonic lung development and asthmatic airway remodeling

Embryonic lung development requires reciprocal endodermal-mesodermal interactions; mediated by various signaling proteins. Wnt/β-catenin is a signaling protein that exhibits the pivotal role in lung development, injury and repair while aberrant expression of Wnt/β-catenin signaling leads to asthmatic airway remodeling: characterized by hyperplasia and hypertrophy of airway smooth muscle cells, alveolar and vascular damage goblet cells metaplasia, and deposition of extracellular matrix; resulting in decreased lung compliance and increased airway resistance. The substantial evidence suggests that Wnt/β-catenin signaling links embryonic lung development and asthmatic airway remodeling. Here, we summarized the recent advances related to the mechanistic role of Wnt/β-catenin signaling in lung development, consequences of aberrant expression or deletion of Wnt/β-catenin signaling in expansion and progression of asthmatic airway remodeling, and linking early-impaired pulmonary development and airway remodeling later in life. Finally, we emphasized all possible recent potential therapeutic significance and future prospectives, that are adaptable for therapeutic intervention to treat asthmatic airway remodeling.

Airway remodeling in asthma: what really matters

Airway remodeling is generally quite broadly defined as any change in composition, distribution, thickness, mass or volume and/or number of structural components observed in the airway wall of patients relative to healthy individuals. However, two types of airway remodeling should be distinguished more clearly: (1) physiological airway remodeling, which encompasses structural changes that occur regularly during normal lung development and growth leading to a normal mature airway wall or as an acute and transient response to injury and/or inflammation, which ultimately results in restoration of a normal airway structures; and (2) pathological airway remodeling, which comprises those structural alterations that occur as a result of either disturbed lung development or as a response to chronic injury and/or inflammation leading to persistently altered airway wall structures and function. This review will address a few major aspects: (1) what are reliable quantitative approaches to assess airway remodeling? (2) Are there any indications supporting the notion that airway remodeling can occur as a primary event, i.e., before any inflammatory process was initiated? (3) What is known about airway remodeling being a secondary event to inflammation? And (4), what can we learn from the different animal models ranging from invertebrate to primate models in the study of airway remodeling? Future studies are required addressing particularly pheno-/endotype-specific aspects of airway remodeling using both endotype-specific animal models and “endotyped” human asthmatics. Hopefully, novel in vivo imaging techniques will be further advanced to allow monitoring development, growth and inflammation of the airways already at a very early stage in life.

Anti-CD69 monoclonal antibody treatment inhibits airway inflammation in a mouse model of asthma

OBJECTIVE

Airway inflammation and airway hyper-responsiveness (AHR) are principle pathological manifestations of asthma. Cluster of differentiation 69 (CD69) is a well-known co-stimulatory factor associated with the activation, proliferation as well as apoptosis of immune cells. This study aims to examine the effect of anti-CD69 monoclonal antibody (mAb) on the pathophysiology of a mouse model of asthma.

METHODS

A murine model of ovalbumin (OVA)-induced allergic airway inflammation was used in this study. Briefly, mice were injected with 20 μg chicken OVA intraperitoneally on Days 0 and 14, followed by aerosol provocation with 1% (0.01 g/ml) OVA on Days 24, 25, and 26. Anti-CD69 mAb or isotype IgG was injected intraperitoneally after OVA challenge; dexamethasone (DXM) was administrated either before or after OVA challenge. AHR, mucus production, and eosinophil infiltration in the peribronchial area were examined. The levels of granulocyte-macrophage colony-stimulating factor (GM-CSF) and interleukin-5 (IL-5) in bronchoalveolar lavage fluid (BALF) were also assayed as indices of airway inflammation on Day 28 following OVA injection.

RESULTS

Pretreatment with DXM together with anti-CD69 mAb treatment after OVA provocation completely inhibited AHR, eosinophil infiltration and mucus overproduction, and significantly reduced BALF IL-5. However, treatment with DXM alone after OVA challenge only partially inhibited AHR, eosinophil infiltration and mucus overproduction, and did not diminish BALF IL-5. Treatment with either DXM or anti-CD69 mAb did not alter the concentration of BALF GM-CSF.

CONCLUSIONS

Anti-CD69 mAb treatment inhibits established airway inflammation as effectively as DXM pretreatment. This study provides a potential alternative therapeutic opportunity for the clinical management of asthma and its exacerbation.

Blockade of dopamine D1-like receptor signalling protects mice against OVA-induced acute asthma by inhibiting B-cell activating transcription factor signalling and Th17 function

Previous studies have consistently demonstrated that dopamine D1-like receptor (D1-like-R) signalling is implicated in the pathogenesis of experimental autoimmune encephalomyelitis and type I diabetes. Given that allergic asthma shares certain disease aetiology similarities with autoimmune diseases, we conducted studies in OVA-induced mice aiming to address the impact of D1-like-R signalling on the pathogenesis of allergic asthma. It was noted that blockade of D1-like-R signalling provided protection for mice against OVA-induced acute asthma. Particularly, treatment of OVA-induced mice with SCH23390, a D1-like-R antagonist, significantly attenuated inflammatory infiltration in the airways along with repressed goblet cell hyperplasia and mucus production, as well as airway resistance. By contrast, administration of SKF83959, a D1-like-R agonist, displayed the opposite effect. Blockade of D1-like-R signalling impaired Th17 function, as manifested by a significant reduction of Th17 cells in the spleen and bronchoalveolar lavage fluid. Mechanistic studies revealed that D1-like-R signalling enhances B-cell activating transcription factor activity, which then transcribes the expression of RORγt, a Th17 transcription factor; accordingly, D1-like-R signalling regulates Th17 differentiation to promote the development of allergic asthma. Taken together, the data obtained in the present suggest that blockade of D1-like-R signalling could be an effective therapeutic strategy for the prevention and treatment of allergic asthma in clinical practice.

Attenuation of allergic airway inflammation in a murine model of asthma by Licochalcone A

CONTEXT

Licochalcone A (Lico A) is a major and biogenetically characteristic chalcone isolated from the root of Xinjiang liquorice, Glycyrrhiza inflata.

OBJECTIVE

We focused on investigating whether Lico A possesses distinct anti-inflammatory activity on a non-infectious mouse model of asthma, and we aimed to elucidate its involvement with the mitogen-activated protein kinases pathway.

METHODS

BALB/c mice that were sensitized and challenged to ovalbumin (OVA) were treated with Lico A (50 mg/kg) 1 h before they were challenged with OVA.

RESULTS

Our study demonstrated that Lico A may effectively inhibit the increase in T-helper type 2 cytokines, such as interleukin (IL)-4, IL-5 and IL-13 in bronchoalveolar lavage fluid, and reduced serum levels of OVA-specific IgE and IgG. Furthermore, Lico A substantially inhibited OVA-induced eosinophilia in lung tissue and mucus hyper-secretion by goblet cells in the airway. Meanwhile, pretreatment with Lico A resulted in a significant reduction in mRNA expression of acidic mammalian chitinase, chitinase 3-like protein 4 (Ym2), E-selectin, Muc5ac, CCL11 and CCR3 in lung tissues and airway hyper-responsiveness to methacholine.

CONCLUSIONS

These findings suggest that Lico A may effectively delay the progression of airway inflammation and could be used as a therapy for patients with allergic airway inflammation.

Tripterygium polyglycosid attenuates the established airway inflammation in asthmatic mice

OBJECTIVE

To investigate the effect of Tripterygium polyglycosid on establishing airway eosinophil infiltration and related airway hyperresponsiveness of asthmatic mice.

METHODS

A mature murine asthmatic model was made with ovabulmin sensitized and challenged C57BL/6 mice. Forty mice were divided into four groups with 10 mice in each group: mice sensitized and challenged with saline (WS group), mice sensitized and challenged with ovalbumin (WO group), mice sensitized and challenged with ovalbumin and treated with Tripterygium polyglycosid (TP group) and Dexamethasone (DXM group). The mice were intraperitoneally injected with 20 μg chicken ovabulmin emulsified in injected alum on days 0 and 14, then were challenged with an aerosol generated from 1% ovabulmin on days 24, 25 and 26. Tripterygium polyglycosid was injected intraperitoneally at 50 mg/kg on days 25, 26 and 27 after ovabulmin challenge. Dexamethasone was administrated to mice at 2 mg/kg on day 21, 23 before ovabulmin challenge. The airway hyperresponsiveness, mucus production, eosinophils in parabronchial area and bronchoalveolar lavage fluid and the level of interleukin-5, granulo-macrophage clone stimulating factor in bronchoalveolar lavage fluid were measured as indexes of inflammation.

RESULTS

Tripterygium polyglycosid treatment after ovabulmin challenge completely inhibited eosinophil infiltration in bronchoalveolar lavage fluid [(0.63 ± 0.34)× 10(4) vs. (75.0 ± 14.8)× 10(4), P<0.05] and the peribrochial area (12.60 ± 3.48 mm(2) vs. 379.0 ± 119.3 mm(2), P<0.05), mucus overproduction in airway (2.8 ± 1.7 vs. 7.1±5.6, P<0.05), and increased interleukin-5 levels in bronchoalveolar lavage fluid (28.8 ± 2.8 pg/mL vs. 7.5 ± 3.5 pg/mL, P<0.05). Meanwhile, Tripterygium polyglycosid treatment after ovabulmin challenge also partially inhibited airway hyperresponsiveness. The level of granulo-macrophage clone stimulating factor in bronchoalveolar lavage fluid didn't change with drugs intervention.

CONCLUSIONS

The administration of Tripterygium polyglycosid could inhibit the established airway inflammation and reduce the airway hyperresponsiveness of allergic asthmatic mice. It provides a possible alternative therapeutic for asthma.

Locally instilled tumor necrosis factor-α antisense oligonucleotide inhibits allergic inflammation via the induction of Tregs

BACKGROUND

Anti-tumor necrosis factor (TNF)-α therapeutics has the potential to alleviate allergic inflammation. However, in previous studies, the systemic administration of anti-TNF-α agents was frequently accompanied by many adverse effects, such as infection, immunogenicity and malignancy. Efforts are made in the present study to evaluate whether or not local administration of TNF-α antisense oligonucleotide would inhibit allergic airway inflammation and influence systemic immune responses in an ovalbumin-induced asthmatic murine model.

METHODS

The treatment effects of TNF-α antisense oligonucleotide on mice, as well as the alternative proportion of regulatory T cells and T(H) 2 cells, were examined and compared with untreated mice.

RESULTS

Local administration of TNF-α antisense oligonucleotide resulted in significantly inhibited TNF-α expression, remarkably decreased inflammatory cell infiltration and dramatically reduced mucus hypersecretion. These treatment effects were associated with induced CD4(+) CD25(+) Foxp3(+) regulatory T cells, reduced T(H) 2 cells and generally decreased T(H) 2-type cytokines expression in bronchoalveolar lavage fluid. Systemic immunosuppression was not triggered by local antisense oligonucleotide administration because the proportion of CD4(+) CD25(+) Foxp3(+) regulatory T cells in the blood, thymus or spleen was not affected. Attenuated 4-1BBL expression was likely involved in the alternative proportion of T cells.

CONCLUSIONS

These findings demonstrate that local administration of TNF-α antisense oligonucleotide contributes to anti-inflammatory action via the enhancement of regulatory T cells-mediated immune tolerance, which is not accompanied by systemic immunosuppression associated with systemically-induced regulatory T cells.

Histopathologic and morphometric evaluation of the nasal and pulmonary airways of cats with experimentally induced asthma

BACKGROUND

Allergic rhinitis frequently occurs as a comorbid condition in asthmatic people, suggesting that the upper and lower airways may be immunologically linked. Our research group has developed an experimental aeroallergen model of asthma in cats. We hypothesized that aeroallergen sensitization and challenge would induce morphologic changes in the nasal airways of cats that mimic those observed in the bronchial airways.

METHODS

Five mixed breed cats were sensitized to Bermuda grass allergen and then serially challenged with aerosolized Bermuda grass allergen to induce an asthmatic phenotype. Four control cats were similarly treated with saline vehicle. Nasal tissues and lungs were processed for histopathological and morphometric analyses.

RESULTS

Eosinophilic inflammation, epithelial hypertrophy and mucous cell metaplasia were observed along the pulmonary axial airway mucosa of allergen-sensitized (asthmatic) cats. Mild eosinophilic inflammation was observed in the nasal airways of asthmatic cats. This alteration was confined primarily to the anterior nasal cavity, resulting in an increase in tissue eosinophils at this site compared to controls (p < 0.05). A marked increase in tissue mast cells was observed throughout all regions of the nasal airways of asthmatic cats compared to control cats (p < 0.05). There was no difference in intraepithelial mucosubstances between the nasal airways of controls and asthmatic cats. There was no correlation between upper and lower airway eosinophils or mast cells.

CONCLUSION

Cats with experimentally induced asthma exhibit morphologic changes in the nasal airways that are distinct from the alterations observed in the lungs. These results are similar to those observed in people with comorbid asthma and allergic rhinitis.

Effects of an anthraquinone derivative from Rheum officinale Baill, emodin, on airway responses in a murine model of asthma

Emodin is a component from traditional Chinese herbal medicines. We focused on investigating whether emodin possesses distinct anti-inflammatory activity on a non-infectious mouse model of asthma, and we aimed to elucidate its involvement with the NF-κB pathway. BALB/c mice that were sensitized and challenged to ovalbumin were treated with emodin (40 mg/kg) 1h before they were challenged with OVA. Our study demonstrated that emodin inhibited OVA-induced increases in eosinophil count; interleukin (IL)-4, IL-5, and IL-13 levels were recovered in bronchoalveolar lavage fluid and reduced serum levels of OVA-specific IgE, IgG, and IgG1. Histological studies demonstrated that emodin substantially inhibited OVA-induced eosinophilia in lung tissue and mucus hyper-secretion by goblet cells in the airway. Furthermore, pretreatment with emodin resulted in a significant reduction in mRNA expression of acidic mammalian chitinase (AMCase), chitinase 3-like protein 4 (Ym2) and Muc5ac in lung tissues and airway hyperresponsiveness to methacholine. These findings suggest that emodin may effectively delay the progression of airway inflammation and could be used as a therapy for patients with allergic airway inflammation.

Characterization of the lung epithelium of wild-type and TLR9(-/-) mice after single and repeated exposures to chicken barn air

Exposure to chicken barn air causes lung injury resulting in lower and upper respiratory symptoms in the poultry workers, and mechanisms of which are not fully understood. The lung injury can initiate modifications such as proliferation of the airway epithelial cells such as Clara cells, type II alveolar (T2) cells and mucus producing goblet cells as part of the innate immune response. Toll-like receptors (TLR) have been suggested to play a role in cell division and proliferation. To understand the effect of TLR9 on Clara cells, T2 and mucus-producing goblet cells, we quantified the numbers of these cells in the lungs of wild-type (WT) and TLR9(-/-) mice exposed to chicken barn air. The mice were exposed for either one day or five or 20 days for 8 h/day. Clara cells and T2 cells were labelled with antibodies, and the mucus cells were identified with Periodic-acid Schiff stain, and quantified in per unit tissue section area. The data show decrease in the number of Clara cells and increase in mucus-producing goblet cells after exposure to chicken barn air in both WT and TLR9(-/-) mice. Numbers of T2 cells increased and decreased in WT and TLR9(-/-) mice, respectively, after exposure to poultry barn air. These data show that exposure to chicken barn air can affect major lung epithelial cells, and allude to the role of TLR9 in regulation of some of these responses.

Protective role of 14-deoxy-11,12-didehydroandrographolide, a noncytotoxic analogue of andrographolide, in allergic airway inflammation

Our group recently reported novel anti-inflammatory effects of andrographolide (2), a bioactive molecule isolated from Andrographis paniculata, in a mouse asthma model. However, 2 has been shown to possess cytotoxic activity. 14-Deoxy-11,12-didehydroandrographolide (1) is an analogue of 2 that can be isolated from A. paniculata. We hypothesized that 1 retains the anti-inflammatory effects for asthma but is devoid of cytotoxicity. In contrast to 2, 1 did not elicit any cytotoxic activity in A549 and BEAS-2B human lung epithelial cells and rat basophilic leukemia (RBL)-2H3 cells using a MTS assay. Compound 1 dose-dependently inhibited ovalbumin (OVA)-induced increases in total and eosinophil counts, IL-4, IL-5, and IL-13 levels in lavage fluid, and serum OVA-specific IgE level in a mouse asthma model. Compound 1 attenuated OVA-induced airway eosinophilia, mucus production, mast cell degranulation, pro-inflammatory biomarker expression in lung tissues, and airway hyper-responsiveness. This substance also blocked p65 nuclear translocation and DNA-binding activity in the OVA-challenged lung and in TNF-α-stimulated human lung epithelial cells. The present findings reveal for the first time that 1 retains the anti-inflammatory activities of 2 for asthma probably through the inhibition of NF-κB. 14-Deoxy-11,12-didehydroandrographolide (1) may be considered as a safer analogue of 2 for the potential treatment of asthma.

Bronchial epithelial cells produce IL-5: implications for local immune responses in the airways

IL-5 is a pleiotropic cytokine that promotes eosinophil differentiation and survival. While naïve bronchial epithelial cells (BEC) produce low levels of IL-5, the role of BEC-derived IL-5 in allergic airway inflammation is unknown. We now show that BEC, isolated from mice with OVA-induced allergic airway disease (AAD), produced elevated levels of IL-5 mRNA and protein as compared to BEC from naïve mice. To determine the contribution of BEC-derived IL-5 to effector responses in the airways, IL-5 deficient bone marrow chimeric mice were generated in which IL-5 expression was restricted to stromal (e.g. BEC) or hematopoietic cells. When subjected to AAD, IL-5 produced by BECs contributed to mucous metaplasia, airway eosinophilia, and OVA-specific IgA levels. Thus, IL-5 production by BEC can impact the microenvironment of the lung, modifying pathologic and protective immune responses in the airways.

Importance of cytokines in murine allergic airway disease and human asthma

Asthma is a common, disabling inflammatory respiratory disease that has increased in frequency and severity in developed nations. We review studies of murine allergic airway disease (MAAD) and human asthma that evaluate the importance of Th2 cytokines, Th2 response-promoting cytokines, IL-17, and proinflammatory and anti-inflammatory cytokines in MAAD and human asthma. We discuss murine studies that directly stimulate airways with specific cytokines or delete, inactivate, neutralize, or block specific cytokines or their receptors, as well as controversial issues including the roles of IL-5, IL-17, and IL-13Ralpha2 in MAAD and IL-4Ralpha expression by specific cell types. Studies of human asthmatic cytokine gene and protein expression, linkage of cytokine polymorphisms to asthma, cytokine responses to allergen stimulation, and clinical responses to cytokine antagonists are discussed as well. Results of these analyses establish the importance of specific cytokines in MAAD and human asthma and have therapeutic implications.

Pseudomonas aeruginosa exotoxin pyocyanin causes cystic fibrosis airway pathogenesis

The cystic fibrosis (CF) airway bacterial pathogen Pseudomonas aeruginosa secretes multiple virulence factors. Among these, the redox active exotoxin pyocyanin (PCN) is produced in concentrations up to 100 mumol/L during infection of CF and other bronchiectatic airways. However, the contributions of PCN during infection of bronchiectatic airways are not appreciated. In this study, we demonstrate that PCN is critical for chronic infection in mouse airways and orchestrates adaptive immune responses that mediate lung damage. Wild-type FVBN mice chronically exposed to PCN developed goblet cell hyperplasia and metaplasia, airway fibrosis, and alveolar airspace destruction. Furthermore, after 12 weeks of exposure to PCN, mouse lungs down-regulated the expression of T helper (Th) type 1 cytokines and polarized toward a Th2 response. Cellular analyses indicated that chronic exposure to PCN profoundly increased the lung population of recruited macrophages, CD4(+) T cells, and neutrophils responsible for the secretion of these cytokines. PCN-mediated goblet cell hyperplasia and metaplasia required Th2 cytokine signaling through the Stat6 pathway. In summary, this study establishes that PCN is an important P. aeruginosa virulence factor capable of directly inducing pulmonary pathophysiology in mice, consistent with changes observed in CF and other bronchiectasis lungs.

Anti-IL-33 antibody treatment inhibits airway inflammation in a murine model of allergic asthma

Interleukin (IL)-33 is a recently described member of the IL-1 family and has been shown to induce production of T helper type 2 cytokines. In this study, an anti-IL-33 antibody was evaluated against pulmonary inflammation in mice sensitized and challenged with ovalbumin. The anti-IL-33 or a control antibody (150 microg/mouse) was given intraperitoneally as five doses before the sensitization and antigen challenge. Treatment with anti-IL-33 significantly reduced serum IgE secretion, the numbers of eosinophils and lymphocytes, and concentrations of IL-4, IL-5, and IL-13 in bronchoalveolar lavage fluid compared with administration of a control antibody. Histological examination of lung tissue demonstrated that anti-IL-33 significantly inhibited allergen-induced lung eosinophilic inflammation and mucus hypersecretion. Our data demonstrate for the first time that anti-IL-33 antibody can prevent the development of asthma in a mouse model and indicate that blockade of IL-33 may be a new therapeutic strategy for allergic asthma.

Advances in mucous cell metaplasia: a plug for mucus as a therapeutic focus in chronic airway disease

Mucous cell metaplasia is induced in response to harmful insults and provides front-line protection to clear the airway of toxic substances and cellular debris. In chronic airway diseases mucous metaplasia persists and results in airway obstruction and contributes significantly to morbidity and mortality. Mucus hypersecretion involves increased expression of mucin genes, and increased mucin production and release. The past decade has seen significant advances in our understanding of the molecular mechanisms by which these events occur. Inflammation stimulates epidermal growth factor receptor activation and IL-13 to induce both Clara and ciliated cells to transition into goblet cells through the coordinated actions of FoxA2, TTF-1, SPDEF, and GABA(A)R. Ultimately, these steps lead to up-regulation of MUC5AC expression, and increased mucin in goblet cell granules that fuse to the plasma membrane through actions of MARCKS, SNAREs, and Munc proteins. Blockade of mucus in exacerbations of asthma and chronic obstructive pulmonary disease may affect morbidity. Development of new therapies to target mucus production and secretion are now possible given the advances in our understanding of molecular mechanisms of mucous metaplasia. We now have a greater incentive to focus on inhibition of mucus as a therapy for chronic airway diseases.

A novel antiinflammatory role for andrographolide in asthma via inhibition of the nuclear factor-kappaB pathway

RATIONALE

Persistent activation of nuclear factor (NF)-kappaB has been associated with the development of asthma. Andrographolide, the principal active component of the medicinal plant Andrographis paniculata, has been shown to inhibit NF-kappaB activity.

OBJECTIVES

We hypothesized that andrographolide may attenuate allergic asthma via inhibition of the NF-kappaB signaling pathway.

METHODS

BALB/c mice sensitized and challenged with ovalbumin (OVA) developed airway inflammation. Bronchoalveolar lavage fluid was assessed for total and differential cell counts, and cytokine and chemokine levels. Serum IgE levels were also determined. Lung tissues were examined for cell infiltration and mucus hypersecretion, and the expression of inflammatory biomarkers. Airway hyperresponsiveness was monitored by direct airway resistance analysis.

MEASUREMENTS AND MAIN RESULTS

Andrographolide dose-dependently inhibited OVA-induced increases in total cell count, eosinophil count, and IL-4, IL-5, and IL-13 levels recovered in bronchoalveolar lavage fluid, and reduced serum level of OVA-specific IgE. It attenuated OVA-induced lung tissue eosinophilia and airway mucus production, mRNA expression of E-selectin, chitinases, Muc5ac, and inducible nitric oxide synthase in lung tissues, and airway hyperresponsiveness to methacholine. In normal human bronchial epithelial cells, andrographolide blocked tumor necrosis factor-alpha-induced phosphorylation of inhibitory kappaB kinase-beta, and downstream inhibitory kappaB alpha degradation, p65 subunit of NF-kappaB phosphorylation, and p65 nuclear translocation and DNA-binding activity. Similarly, andrographolide blocked p65 nuclear translocation and DNA-binding activity in the nuclear extracts from lung tissues of OVA-challenged mice.

CONCLUSIONS

Our findings implicate a potential therapeutic value of andrographolide in the treatment of asthma and it may act by inhibiting the NF-kappaB pathway at the level of inhibitory kappaB kinase-beta activation.

Selective p38α mitogen-activated protein kinase inhibitor attenuates lung inflammation and fibrosis in IL-13 transgenic mouse model of asthma

p38 Mitogen-activated protein kinase (MAPK) plays a critical role in the activation of inflammatory cells. We investigated the anti-inflammatory effects of a p38α-selective MAPK inhibitor (SD-282) in a mouse transgenic (CC10:IL-13) asthma model. The CC-10-driven over-expression of IL-13 in the mouse lung/airway has been shown to result in a remarkable phenotype recatitulating many features of asthma and characterized by eosinophilic and mononuclear inflammation, with airway epithelial cell hypertrophy, mucus cell metaplasia, the hyperproduction of neutral and acidic mucus, the deposition of Charcot–Leyden-like crystal, and airway sub-epitheilial fibrosis. Here we show how activated p38 MAPK can be observed in the lungs at the onset of asthma ie, around 8 weeks of age in both female and male mice. We also show that administration of a p38α MAPK selective inhibitor, SD-282 at 30 or 90 mg/kg, twice a day for a period of four weeks beginning at the onset of asthma, significantly reduced the inflammation (p < 0.001); hyperplasia of airway epithelium (p < 0.05); goblet cell metaplasia and mucus hypersecretion (p < 0.001) and reduced lung remodeling and fibrosis (p < 0.01), alleviating the severity of lung damage as measured by a composite score (p < 0.05). Furthermore, SD-282 significantly reduced activated p38 MAPK in the lymphocytes and epithelial cells (p < 0.001). Simultaneously, identical studies were conducted with an anti-fibrotic TGFβR1 kinase inhibitor (SD-208) which demonstrated anti-fibrotic but not anti-inflammatory properties. These findings suggest that the p38α-selective MAPK inhibitor may have dual therapeutic potential in attenuating both the inflammatory component and the fibrotic component of asthma and other Th2-polarized inflammatory lung diseases.

Time-dependent airway epithelial and inflammatory cell responses induced by influenza virus A/PR/8/34 in C57BL/6 mice

The present study examines the kinetics of airway epithelial remodeling and inflammation in the airways of C57BL/6J mice infected with influenza virus A/PR/8/34 (PR8). Mice were intranasally instilled with 50 plaque forming units (pfu) of virus or its respective vehicle, saline, and then were sacrificed at 3, 7, 10, 15, or 21 days postinfection (dpi). PR8 treatment resulted in airway epithelial cell regeneration as suggested by proliferating cell nuclear antigen (PCNA) positive staining at 7 and 10 dpi and mucous cell metaplasia (MCM) evident at 10, 15, and 21 dpi. PR8 treatment resulted in a classic pattern of inflammation observed in bronchoalveolar lavage fluid (BALF), in which neutrophils peaked at 3 and 7 dpi and monocytes, lymphocytes, and eosinophils peaked at 10 dpi before returning to background levels of detection. Chemokine (MCP-1) and cytokine (IL-6, TNF-alpha, IFN-gamma, IL-5, IL-4, and IL-9) levels peaked at 7 dpi in BALF. IL-13 levels were unaffected by PR8 treatment. Concurrent with inflammation, MUC5AC gene expression was markedly increased by PR8 treatment at 7 dpi. Collectively, the results of this study indicate that the onset of MCM in airway epithelium occurs during the remodeling process and persists after the inflammatory response has diminished.

Glycogen synthase kinase-3beta inhibition attenuates asthma in mice

RATIONALE

Persistent activation of nuclear factor-kappaB has been associated with the development of asthma. Glycogen synthase kinase-3beta is known to regulate the activity of nuclear factor-kappaB.

OBJECTIVES

We hypothesized that inhibition of glycogen synthase kinase-3beta may have anti-inflammatory effects in allergic asthma.

METHODS

BALB/c mice sensitized and challenged with ovalbumin developed airway inflammation. Bronchoalveolar lavage fluid was assessed for total and differential cell counts, and for cytokine and chemokine levels. Lung tissues were examined for cell infiltration and mucus hypersecretion, and for the expression of inflammatory biomarkers. Serum immunoglobulin E levels were determined by enzyme-linked immunosorbant assay. Airway hyperresponsiveness was monitored by direct airway resistance analysis.

MEASUREMENTS AND MAIN RESULTS

Intravenous administration of 4-benzyl-2-methyl-1,2,4-thiadiazolidine-3,5-dione (TDZD-8), a selective glycogen synthase kinase-3beta inhibitor, significantly inhibited ovalbumin-induced increases in total cell counts, eosinophil counts, and IL-5, IL-13, and eotaxin levels recovered in bronchoalveolar lavage fluid in a dose-dependent manner. TDZD-8 substantially reduced the serum levels of ovalbumin-specific IgE. Histologic studies showed that TDZD-8 dramatically inhibited ovalbumin-induced lung tissue eosinophilia and airway mucus production. TDZD-8 also markedly suppressed ovalbumin-induced mRNA expression of intercellular adhesion molecule-1, vascular cell adhesion molecule-1, Muc5ac, and three members of the chitinase family (acidic mammalian chitinase, Ym1, and Ym2). In addition, TDZD-8 significantly reduced ovalbumin-induced airway hyperresponsiveness to inhaled methacholine. Western blot analysis of whole lung lysates revealed that TDZD-8 markedly attenuated the phosphorylation of the nuclear factor-kappaB subunit p65 from ovalbumin-challenged mice.

CONCLUSIONS

Our findings suggest that inhibition of glycogen synthase kinase-3beta may provide a novel means for the treatment of allergic airway inflammation.

Anti-inflammatory activity of inhaled IL-4 receptor-alpha antisense oligonucleotide in mice

The Th2 cytokines IL-4 and IL-13 mediate allergic pulmonary inflammation and airways hyperreactivity (AHR) in asthma models through signaling dependent upon the IL-4 receptor-alpha chain (IL-4Ralpha). IL-13 has been further implicated in the overproduction of mucus by the airway epithelium and in lung remodeling that commonly accompanies chronic inflammation. IL-4Ralpha-deficient mice are resistant to allergen-induced asthma, highlighting the therapeutic promise of selective molecular inhibitors of IL-4Ralpha. We designed a chemically modified IL-4Ralpha antisense oligonucleotide (IL-4Ralpha ASO) that specifically inhibits IL-4Ralpha protein expression in lung eosinophils, macrophages, dendritic cells, and airway epithelium after inhalation in allergen-challenged mice. Inhalation of IL-4Ralpha ASO attenuated allergen-induced AHR, suppressed airway eosinophilia and neutrophilia, and inhibited production of airway Th2 cytokines and chemokines in previously allergen-primed and -challenged mice. Histologic analysis of lungs from these animals demonstrated reduced goblet cell metaplasia and mucus staining that correlated with inhibition of Muc5AC gene expression in lung tissue. Therapeutic administration of inhaled IL-4Ralpha ASO in chronically allergen-challenged mice produced a spectrum of anti-inflammatory activity similar to that of systemically administered Dexamethasone with the added benefit of reduced airway neutrophilia. These data support the potential utility of a dual IL-4 and IL-13 oligonucleotide inhibitor in allergy/asthma, and suggest that local inhibition of IL-4Ralpha in the lung is sufficient to suppress allergen-induced pulmonary inflammation and AHR.

Early exposure to a nonhygienic environment alters pulmonary immunity and allergic responses

The hygiene hypothesis suggests that early life exposure to a nonhygienic environment that contains endotoxin reduces the risk of developing allergic diseases. The mechanisms underlying the hygiene hypothesis are unclear and may involve subtle immune system interactions that occur during maturation. Experimental objectives of this study were to use a novel animal model to test the hygiene hypothesis and to characterize early life immune system responses to a nonhygienic environment. Mice were reared in corn dust, a grain-processing byproduct with a high-endotoxin content and microbial products or in a low-endotoxin environment. The influence of early or later life exposure to corn dust on a subsequent allergen stimulus (ovalbumin) was assessed by bronchoalveolar lavage (BAL) cell analysis, lung histology, serum IgE, and BAL cytokine measurements. The influence of the corn dust environment on the developing pulmonary immune system was assessed by BAL cell analysis and immunostaining of lung tissue. The corn dust environment contained significantly more endotoxin ( P < 0.001), and the dust exposures attenuated the cellular inflammatory response to ovalbumin in the adult mouse ( P < 0.01) but did not reduce serum IgE levels or alter baseline BAL fluid proinflammatory cytokine levels. The corn dust environment did not induce significant neutrophilia in lavage fluid but significantly increased the number of antigen-presenting cells in alveolar walls early in life by ∼37%. In conclusion, exposure to a nonhygienic environment did not induce significant airway neutrophilia, yet altered the population of immunologically active cells in the lung and reduced subsequent allergic inflammation.

Inhibition of phosphoinositide 3-kinase delta attenuates allergic airway inflammation and hyperresponsiveness in murine asthma model

P110delta phosphoinositide 3-kinase (PI3K) plays a pivotal role in the recruitment and activation of certain inflammatory cells. Recent findings revealed that the activity of p110delta also contributes to allergen-IgE-induced mast cell activation and vascular permeability. We investigated the role of p110delta in allergic airway inflammation and hyperresponsiveness using IC87114, a selective p110delta inhibitor, in a mouse asthma model. BALB/c mice were sensitized with OVA and, upon OVA aerosol challenge, developed airway eosinophilia, mucus hypersecretion, elevation in cytokine and chemokine levels, up-regulation of ICAM-1 and VCAM-1 expression, and airway hyperresponsiveness. Intratracheal administration of IC87114 significantly (P<0.05) attenuated OVA-induced influx into lungs of total leukocytes, eosinophils, neutrophils, and lymphocytes, as well as levels of IL-4, IL-5, IL-13, and RANTES in a dose-dependent manner. IC87114 also significantly (P<0.05) reduced the serum levels of total IgE and OVA-specific IgE and LTC(4) release into the airspace. Histological studies show that IC87114 inhibited OVA-induced lung tissue eosinophilia, airway mucus production, and inflammation score. In addition, IC87114 significantly (P<0.05) suppressed OVA-induced airway hyperresponsiveness to inhaled methacholine. Western blot analyses of whole lung tissue lysates shows that IC87114 markedly attenuated the OVA-induced increase in expression of IL-4, IL-5, IL-13, ICAM-1, VCAM-1, RANTES, and eotaxin. Furthermore, IC87114 treatment markedly attenuated OVA-induced serine phosphorylation of Akt, a downstream effector of PI3K signaling. Taken together, our findings implicate that inhibition of p110delta signaling pathway may have therapeutic potential for the treatment of allergic airway inflammation.

CD4+ CD30+ T cells perpetuate IL-5 production in Dermatophagoides pteronyssinus allergic patients

BACKGROUND

Airway allergic diseases are regulated by interleukin (IL)-5, which causes infiltration of eosinophils into the bronchial epithelium, and by IL-4 which increases serum immunoglobulin E (IgE) production and promotes CD30 expression on Th cells. CD30 generates a costimulatory signal involved in apoptosis or cell proliferation, depending on the microenvironment. Our aims were: (i) to analyze if CD4+ CD30+ T cells from allergic patients proliferate in response to Dermatophagoides pteronyssinus, and (ii) if upon stimulation this cell population produces IL-4 and IL-5.

METHODS

Peripheral blood mononuclear cell (PBMC) from 17 allergic rhinitis and mild allergic asthma patients and 12 healthy nonallergic individuals were stimulated with allergen in the presence or absence of anti-IL-4, anti-IL-5 or anti-IL-4Ralpha monoclonal antibodies (mAbs). TdT-mediated dUTP nick end-labeling (TUNEL) assay, 7-aminoactinomycin-D (7-AAD) intercalation, and flow cytometry were used to determine the CD4+ CD30+ blasts percentage, cell proliferation, apoptosis, and intracellular cytokines after 7 culture days.

RESULTS

Cell proliferation induced with allergen showed that 90% of the allergen-stimulated blasts were CD4+, 50% of which were CD30+. Allergen-stimulated PBMC showed a progressive increase (mean: from 7% to 23%) of CD4+ CD30+IFN-gamma+ and CD4+ CD30+IL-4+ blasts which diminished (mean: 6%) after 5 culture days. In contrast, CD4+ CD30+IL-5+ blasts showed a continuous progression (from 12% to 24%) that maintained after 7 culture days. The vast majority of CD4+ CD30+ blasts were negative to 7-AAD or TUNEL. Additionally, a significant decrease (34%) was observed in the number of CD4+ CD30+ blasts when IL-4 was neutralized.

CONCLUSIONS

These data suggest that specific allergen stimulation of PBMC isolated from allergic patients generates a nonapoptotic CD4+ CD30+ blast subset that produces IL-5.

An anti-inflammatory role for a phosphoinositide 3-kinase inhibitor LY294002 in a mouse asthma model

Phosphoinositide 3-kinase (PI3K) exhibits broad functional effects in immune cells. We investigated the role of PI3K in allergic airway inflammation using LY294002, a specific PI3K inhibitor, in a mouse asthma model. BALB/c mice were sensitized and challenged with ovalbumin (OVA), and developed airway eosinophilia, mucus hypersecretion, elevation in cytokine levels, and airway hyperresponsiveness. Intratracheal administration of LY294002 significantly inhibited OVA-induced increases in total cell counts, eosinophil counts, and IL-5, IL-13, and eotaxin levels in bronchoalveolar lavage fluid. Histological studies show that LY294002 dramatically inhibited OVA-induced lung tissue eosinophilia and airway mucus production. In addition, LY294002 significantly suppressed OVA-induced airway hyperresponsiveness to inhaled methacholine. Western blot analysis of whole lung lysates shows that LY294002 markedly attenuated OVA-induced serine phosphorylation of Akt, a direct downstream substrate of PI3K. Taken together, our findings suggest that inhibition of PI3K signaling pathway can suppress T-helper type 2 (Th2) cytokine production, eosinophil infiltration, mucus production, and airway hyperresponsiveness in a mouse asthma model and may have therapeutic potential for the treatment of allergic airway inflammation.

Inhaled p38alpha mitogen-activated protein kinase antisense oligonucleotide attenuates asthma in mice

The p38 mitogen-activated protein kinase (MAPK) plays a critical role in the activation of inflammatory cells. Therefore, we investigated the antiinflammatory effects of a respirable p38alpha MAPK antisense oligonucleotide (p38alpha-ASO) in a mouse asthma model. A potent and selective p38alpha-ASO was characterized in vitro. Inhalation of aerosolized p38alpha-ASO using an aerosol chamber dosing system produced measurable lung deposition of ASO and significant reduction of ovalbumin (OVA-)-induced increases in total cells, eosinophils, and interleukin 4 (IL-4), IL-5, and IL-13 levels in bronchoalveolar lavage fluid, and dose-dependent inhibition of airway hyperresponsiveness in allergen-challenged mice. Furthermore, inhaled p38alpha-ASO markedly inhibited OVA-induced lung tissue eosinophilia and airway mucus hypersecretion. Quantitative polymerase chain reaction analysis of bronchoalveolar lavage fluid cells and peribronchial lymph node cells showed that p38alpha-ASO significantly reduced p38alpha MAPK mRNA expression. Nose-only aerosol exposure of mice verified the p38alpha-ASO-induced inhibition of OVA-induced pulmonary eosinophilia, mucus hypersecretion, and airway hyperresponsiveness. None of the effects of the p38alpha-ASO were produced by a six-base mismatched control oligonucleotide. These findings demonstrate antisense pharmacodynamic activity in the airways after aerosol delivery and suggest that a p38alpha MAPK ASO approach may have therapeutic potential for asthma and other inflammatory lung diseases.

Neutrophil elastase induces mucus cell metaplasia in mouse lung

Goblet cell hyperplasia in the superficial airway epithelia is a signature pathological feature of chronic bronchitis and cystic fibrosis. In these chronic inflammatory airway diseases, neutrophil elastase (NE) is found in high concentrations in the epithelial lining fluid. NE has been reported to trigger mucin secretion and increase mucin gene expression in vitro. We hypothesized that chronic NE exposure to murine airways in vivo would induce goblet cell metaplasia. Human NE (50 microg) or PBS saline was aspirated intratracheally by male Balb/c (6 wk of age) mice on days 1, 4, and 7. On days 8, 11, and 14, lung tissues for histology and bronchoalveolar lavage (BAL) samples for cell counts and cytokine levels were obtained. NE induced Muc5ac mRNA and protein expression and goblet cell metaplasia on days 8, 11, and 14. These cellular changes were the result of proteolytic activity, since the addition of an elastase inhibitor, methoxysuccinyl Ala-Ala-Pro-Val chloromethylketone (AAPV-CMK), blocked NE-induced Muc5ac expression and goblet cell metaplasia. NE significantly increased keratinocyte-derived chemokine and IL-5 in BAL and increased lung tissue inflammation and BAL leukocyte counts. The addition of AAPV-CMK reduced these measures of inflammation to control levels. These experiments suggest that NE proteolytic activity initiates an inflammatory process leading to goblet cell metaplasia.

Anti-Inflammatory Effects of Mitogen-Activated Protein Kinase Kinase Inhibitor U0126 in an Asthma Mouse Model

Mitogen-activated protein kinase (MAPK) signaling cascade plays a pivotal role in the activation of inflammatory cells. Recent findings revealed that the activity of p42/44 MAPK (also known as extracellular signal-regulated kinase (ERK)) in the lungs was significantly higher in asthmatic mice than in normal controls. We hypothesized that inhibition of ERK activity may have anti-inflammatory effects in allergic asthma. BALB/c mice were sensitized with OVA and, upon OVA aerosol challenge, developed airway eosinophilia, mucus hypersecretion, elevation in cytokine and chemokine levels, up-regulation of VCAM-1 expression, and airway hyperresponsiveness. Intraperitoneal administration of U0126, a specific MAPK/ERK kinase inhibitor, significantly (p < 0.05) inhibited OVA-induced increases in total cell counts, eosinophil counts, and IL-4, IL-5, IL-13, and eotaxin levels recovered in bronchoalveolar lavage fluid in a dose-dependent manner. U0126 also substantially (p < 0.05) reduced the serum levels of total IgE and OVA-specific IgE and IgG1. Histological studies show that U0126 dramatically inhibited OVA-induced lung tissue eosinophilia, airway mucus production, and expression of VCAM-1 in lung tissues. In addition, U0126 significantly (p < 0.05) suppressed OVA-induced airway hyperresponsiveness to inhaled methacholine in a dose-dependent manner. Western blot analysis of whole lung lysates shows that U0126 markedly attenuated OVA-induced tyrosine phosphorylation of ERK1/2. Taken together, our findings implicate that inhibition of ERK signaling pathway may have therapeutic potential for the treatment of allergic airway inflammation.

The new histologic classification of chronic rhinosinusitis

Two histologic patterns of disease are found in chronic rhinosinusitis. The first is dominated by eosinophilia and polypoid changes. Glandular hyperplasia and hypertrophy characterize the second. We present the evidence supporting the existence of these two patterns of disease and link these histologic patterns to the larger pathophysiologic processes that drive them. This histologic classification should be acknowledged both in the clinical setting and in laboratory research of chronic rhinosinusitis.

A causative relationship exists between eosinophils and the development of allergic pulmonary pathologies in the mouse

Asthma and mouse models of allergic respiratory inflammation are invariably associated with a pulmonary eosinophilia; however, this association has remained correlative. In this report, a causative relationship between eosinophils and allergen-provoked pathologies was established using eosinophil adoptive transfer. Eosinophils were transferred directly into the lungs of either naive or OVA-treated IL-5(-/-) mice. This strategy resulted in a pulmonary eosinophilia equivalent to that observed in OVA-treated wild-type animals. A concomitant consequence of this eosinophil transfer was an increase in Th2 bronchoalveolar lavage cytokine levels and the restoration of intracellular epithelial mucus in OVA-treated IL-5(-/-) mice equivalent to OVA-treated wild-type levels. Moreover, the transfer also resulted in the development of airway hyperresponsiveness. These pulmonary changes did not occur when eosinophils were transferred into naive IL-5(-/-) mice, eliminating nonspecific consequences of the eosinophil transfer as a possible explanation. Significantly, administration of OVA-treated IL-5(-/-) mice with GK1.5 (anti-CD4) Abs abolished the increases in mucus accumulation and airway hyperresponsiveness following adoptive transfer of eosinophils. Thus, CD4(+) T cell-mediated inflammatory signals as well as signals derived from eosinophils are each necessary, yet alone insufficient, for the development of allergic pulmonary pathology. These data support an expanded view of T cell and eosinophil activities and suggest that eosinophil effector functions impinge directly on lung function.