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Ethnopharmacological Relevance: Callicarpa japonica Thunb., as an herbal medicine has been used for the treatment of inflammatory diseases in China and Korea., Materials and Methods: Ultra performance liquid chromatography-photodiode array-quadrupole time-of-flight mass spectrometer (UPLC-PDA-QTof MS) was used to detect the major phenylethanoid glycosides in the C. japonica extract. BALB/c mice were intraperitoneally sensitized by ovalbumin (OVA) (on days 0 and 7) and challenged by OVA aerosol (on days 11-13) to induce airway inflammatory response. The mice were also administered with C. japonica Thunb. (CJT) (20 and 40 mg/kg Per oral) on days 9-13. CJT pretreatment was conducted in lipopolysaccharide (LPS)-stimulated RAW264.7 or phorbol 12-myristate 13-acetate (PMA)-stimulated A549 cells., Results: CJT administration significantly reduced the secretion of Th2 cytokines, TNF-α, IL-6, immunoglobulin E (IgE) and histamine, and the recruitment of eosinophils in an OVA-exposed mice. In histological analyses, the amelioration of inflammatory cell influx and mucus secretion were observed with CJT. The OVA-induced airway hyperresponsiveness (AHR), iNOS expression and NF-κB activation were effectively suppressed by CJT administration. In addition, CJT led to the upregulation of HO-1 expression. In an in vitro study, CJT pretreatment suppressed the LPS-induced TNF-α secretion in RAW264.7 cells and attenuated the PMA-induced IL-6, IL-8 and MCP-1 secretion in A549 cells. These effects were accompanied by downregulated NF-κB phosphorylation and by upregulated HO-1 expression., Conclusion: These results suggested that CJT has protective activity against OVA-induced airway inflammation via downregulation of NF-κB activation and upregulation of HO-1, suggesting that CJT has preventive potential for the development of allergic asthma., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Background: Asthma is a chronic inflammatory disease characterized by airways hyper-responsiveness (AHR), reversible airway obstruction, and airway inflammation and remodeling. We previously showed that Syk modulates methacholine-induced airways contractility in naïve mice and in mice with allergic airways inflammation. We hypothesize that Syk plays a role in the pathogenesis of AHR; this was evaluated in a chronic 8-week mouse model of house dust mite (HDM)-induced allergic airways inflammation., Methods: We used the Sykflox/flox//rosa26CreERT2 conditional Syk knock-out mice to assess the role of Syk prior to HDM exposure, and treated HDM-sensitized mice with the Syk inhibitor, GSK143, to evaluate its role in established allergic airways inflammation. Respiratory mechanics and methacholine (MCh)-responsiveness were assessed using the flexiVent® system. Lungs underwent bronchoalveolar lavage to isolate inflammatory cells or were frozen for determination of gene expression in tissues., Results: MCh-induced AHR was observed following HDM sensitization in the Syk-intact (Sykflox/flox) and vehicle-treated BALB/c mice. MCh responsiveness was reduced to control levels in HDM-sensitized Sykdel/del mice and in BALB/c and Sykflox/flox mice treated with GSK143. Both Sykdel/del and GSK143-treated mice mounted appropriate immune responses to HDM, with HDM-specific IgE levels that were comparable to Sykflox/flox and vehicle-treated BALB/c mice. HDM-induced increases in bronchoalveolar lavage cell counts were attenuated in both Sykdel/del and GSK143-treated mice, due primarily to decreased neutrophil recruitment. Gene expression analysis of lung tissues revealed that HDM-induced expression of IL-17 and CXCL-1 was significantly attenuated in both Sykdel/del and GSK143-treated mice., Conclusion: Syk inhibitors may play a role in the management of neutrophilic asthma., Competing Interests: The authors have declared that no competing interests exist.

The catalytical isoforms p110γ and p110δ of phosphatidylinositide 3-kinase γ (PI3Kγ) and PI3Kδ play an important role in the pathogenesis of asthma. Two key elements in allergic asthma are increased levels of eosinophils and IgE. Dual pharmacological inhibition of p110γ and p110δ reduces asthma-associated eosinophilic lung infiltration and ameliorates disease symptoms, whereas the absence of enzymatic activity in p110γKOδD910A mice increases IgE and basal eosinophil counts. This suggests that long-term inhibition of p110γ and p110δ might exacerbate asthma. Here, we analysed mice genetically deficient for both catalytical subunits (p110γ/δ-/-) and determined basal IgE and eosinophil levels and the immune response to ovalbumin-induced asthma. Serum concentrations of IgE, IL-5 and eosinophil numbers were significantly increased in p110γ/δ-/- mice compared to single knock-out and wildtype mice. However, p110γ/δ-/- mice were protected against OVA-induced infiltration of eosinophils, neutrophils, T and B cells into lung tissue and bronchoalveolar space. Moreover, p110γ/δ-/- mice, but not single knock-out mice, showed a reduced bronchial hyperresponsiveness. We conclude that increased levels of eosinophils and IgE in p110γ/δ-/- mice do not abolish the protective effect of p110γ/δ-deficiency against OVA-induced allergic airway inflammation.

Background: In allergen-induced asthma, activated mast cells start the lung inflammatory process with degranulation, cytokine synthesis, and mediator release. Bruton's tyrosine kinase (Btk) activity is required for the mast cell activation during IgE-mediated secretion., Methods: This study characterized a novel inhaled Btk inhibitor RN983 in vitro and in ovalbumin allergic mouse models of the early (EAR) and late (LAR) asthmatic response., Results: RN983 potently, selectively, and reversibly inhibited the Btk enzyme. RN983 displayed functional activities in human cell-based assays in multiple cell types, inhibiting IgG production in B-cells with an IC50 of 2.5 ± 0.7 nM and PGD2 production from mast cells with an IC50 of 8.3 ± 1.1 nM. RN983 displayed similar functional activities in the allergic mouse model of asthma when delivered as a dry powder aerosol by nose-only inhalation. RN983 was less potent at inhibiting bronchoconstriction (IC50(RN983) = 59 μg/kg) than the β-agonist salbutamol (IC50(salbutamol) = 15 μg/kg) in the mouse model of the EAR. RN983 was more potent at inhibiting the antigen induced increase in pulmonary inflammation (IC50(RN983) = <3 μg/kg) than the inhaled corticosteroid budesonide (IC50(budesonide) = 27 μg/kg) in the mouse model of the LAR., Conclusions: Inhalation of aerosolized RN983 may be effective as a stand-alone asthma therapy or used in combination with inhaled steroids and β-agonists in severe asthmatics due to its potent inhibition of mast cell activation., Competing Interests: Author Disclosure Statement All authors were employed by Hoffmann-La Roche Inc. when experiments were performed.

Asthma is defined by airway inflammation and hyperresponsiveness, and contributes to morbidity and mortality worldwide. Although bronchodilation is a cornerstone of treatment, current bronchodilators become ineffective with worsening asthma severity. We investigated an alternative pathway that involves activating the airway smooth muscle enzyme, soluble guanylate cyclase (sGC). Activating sGC by its natural stimulant nitric oxide (NO), or by pharmacologic sGC agonists BAY 41-2272 and BAY 60-2770, triggered bronchodilation in normal human lung slices and in mouse airways. Both BAY 41-2272 and BAY 60-2770 reversed airway hyperresponsiveness in mice with allergic asthma and restored normal lung function. The sGC from mouse asthmatic lungs displayed three hallmarks of oxidative damage that render it NO-insensitive, and identical changes to sGC occurred in human lung slices or in human airway smooth muscle cells when given chronic NO exposure to mimic the high NO in asthmatic lung. Our findings show how allergic inflammation in asthma may impede NO-based bronchodilation, and reveal that pharmacologic sGC agonists can achieve bronchodilation despite this loss.

Obesity is a major risk factor for asthma, which is characterized by airway hyperreactivity (AHR). In obesity-associated asthma, AHR may be regulated by non-TH2 mechanisms. We hypothesized that airway reactivity is regulated by insulin in the CNS, and that the high levels of insulin associated with obesity contribute to AHR. We found that intracerebroventricular (ICV)-injected insulin increases airway reactivity in wild-type, but not in vesicle acetylcholine transporter knockdown (VAChT KD(HOM-/-)), mice. Either neutralization of central insulin or inhibition of extracellular signal-regulated kinases (ERK) normalized airway reactivity in hyperinsulinemic obese mice. These effects were mediated by insulin in cholinergic nerves located at the dorsal motor nucleus of the vagus (DMV) and nucleus ambiguus (NA), which convey parasympathetic outflow to the lungs. We propose that increased insulin-induced activation of ERK in parasympathetic pre-ganglionic nerves contributes to AHR in obese mice, suggesting a drug-treatable link between obesity and asthma., (Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.)

Background/aims: We sought to increase our understanding of the rhinitis-asthma relationship and improve strategies for the treatment of patients with these diseases. The aim of this study was to identify a connection between upper airway inflammation and lower airway responsiveness., Methods: We counted eosinophils on nasal smears, and performed spirometry, allergic skin tests, and methacholine challenge tests in 308 schoolchildren plus a questionnaire on respiratory symptoms. The methacholine concentration causing a 20% fall in forced expiratory volume in 1 second (PC20 < 25 mg/mL) was used as the threshold of bronchial hyperresponsiveness (BHR)., Results: In total, 26% of subjects had positive nasal eosinophils on a smear, and 46.2% of subjects had BHR at < 25 mg/mL methacholine PC20. Nasal symptoms were higher in subjects with than without nasal eosinophils (p = 0.012). Asthma symptoms did not differ between subjects with and without nasal eosinophils. Nasal eosinophils were higher in subjects with atopy than those without (p = 0.006), and there was no difference in PC20 methacholine according to atopy (15.5 ± 1.07 vs. 17.5 ± 0.62; p > 0.05). No difference in BHR was detected when comparing subjects with and without nasal eosinophils. There were significant differences in the PC20 between subjects with greater than 50% nasal eosinophils and without nasal eosinophils (11.01 ± 2.92 mg/mL vs. 17.38 ± 0.61 mg/mL; p < 0.001)., Conclusions: These findings demonstrated that nasal eosinophilic inflammation might contribute to lower airway responsiveness in schoolchildren, based on an epidemiological survey.

Background: Respiratory syncytial virus (RSV) is one of the most frequently observed pathogens during infancy and childhood. However, the corresponding pathogenesis has not been determined to date. We previously demonstrated that IFN-γ plays an important role in RSV pathogenesis, and SARM-TRIF-signaling pathway could regulate the production of IFN-γ. This study is to investigate whether T cells or innate immune cells are the predominant producers of IFN-γ, and further to explore other culprits in addition to IFN-γ in the condition of RSV infection., Methods: Normal BALB/c mice and nude mice deficient in T cells were infected intranasally with RSV. Leukocytes in bronchoalveolar lavage fluid were counted, lung histopathology was examined, and airway hyperresponsiveness (AHR) was measured by whole-body plethysmography. IFN-γ and MMP-12 were detected by ELISA. MMP408, a selective MMP-12 inhibitor, was given intragastrically. Resveratrol, IFN-γ neutralizing antibody and recombinant murine IFN-γ were administered intraperitoneally. SARM and TRIF protein were semi-quantified by Western blot. siRNA was used to knock-down SARM expression., Results: RSV induced significant airway inflammation and AHR in both mice; IFN-γ was significantly increased in BALB/c mice but not in nude mice. MMP-12 was dramatically increased in both mice but earlier in nude mice. When MMP-12 was inhibited by MMP408, RSV-induced respiratory symptoms were alleviated. SARM was significantly suppressed while TRIF was significantly enhanced in both mice strains. Following resveratrol administration in nude mice, 1) SARM inhibition was prevented, 2) TRIF and MMP-12 were correspondingly down-regulated and 3) airway disorders were subsequently alleviated. Moreover, when SARM was efficiently knocked down using siRNA, TRIF and MMP-12 were markedly enhanced, and the anti-RSV effects of resveratrol were remarkably abrogated. MMP-12 was significantly increased in the IFN-γ neutralizing antibody-treated BALB/c mice but reduced in the recombinant murine IFN-γ-treated nude mice., Conclusions: MMP-12 can result in at least part of the airway inflammation and AHR independent of IFN-γ. And SARM-TRIF- signaling pathway is involved in regulating the overproduction of MMP-12. To the best of our knowledge, this study is the first that has examined the effects of SARM on MMP-12 and further highlights the potential to target SARM-TRIF-MMP-12 cascades to treat RSV infection.

Context: Nodakenin is a major coumarin glucoside in the root of Peucedanum decursivum Maxim, a commonly used traditional Chinese medicine for the treatment of asthma and chronic bronchitis for thousands of years., Objective: In this work, the anti-asthma potential of nodakenin was studied by investigation of its effect to suppress airway inflammation, hyper-responsiveness and remodeling in a murine model of chronic asthma., Materials and Methods: BALB/c mice sensitized to ovalbumin (OVA) were challenged with aerosolized OVA for 8 weeks, orally administered with nodakenin at doses of 5, 10 and 20 mg/kg before each OVA challenge., Results: Compared with the model group, nodakenin treatment markedly inhibited airway inflammation, hyper-responsiveness and remodeling, showing improvement in subepithelial fibrosis, smooth muscle hypertrophy, and goblet cell hyperplasia, and decreased levels of interleukin (IL)-4, IL-5, IL-13 and matrix metalloproteinase-2/-9 in bronchoalveolar lavage fluid, and the level of OVA-specific IgE in serum. In addition, the NF-κB DNA-binding activity in lung tissues was also reduced by nodakenin treatment., Conclusions: These data indicated that nodakenin might mitigate the development of chronic experimental allergic asthma.

Background: Phospholipase Cε (PLCε) is an effector of Ras and Rap small GTPases and expressed in non-immune cells. It is well established that PLCε plays an important role in skin inflammation, such as that elicited by phorbol ester painting or ultraviolet irradiation and contact dermatitis that is mediated by T helper (Th) 1 cells, through upregulating inflammatory cytokine production by keratinocytes and dermal fibroblasts. However, little is known about whether PLCε is involved in regulation of inflammation in the respiratory system, such as Th2-cells-mediated allergic asthma., Methods: We prepared a mouse model of allergic asthma using PLCε+/+ mice and PLCεΔX/ΔX mutant mice in which PLCε was catalytically-inactive. Mice with different PLCε genotypes were immunized with ovalbumin (OVA) followed by the challenge with an OVA-containing aerosol to induce asthmatic response, which was assessed by analyzing airway hyper-responsiveness, bronchoalveolar lavage fluids, inflammatory cytokine levels, and OVA-specific immunoglobulin (Ig) levels. Effects of PLCε genotype on cytokine production were also examined with primary-cultured bronchial epithelial cells., Results: After OVA challenge, the OVA-immunized PLCεΔX/ΔX mice exhibited substantially attenuated airway hyper-responsiveness and broncial inflammation, which were accompanied by reduced Th2 cytokine content in the bronchoalveolar lavage fluids. In contrast, the serum levels of OVA-specific IgGs and IgE were not affected by the PLCε genotype, suggesting that sensitization was PLCε-independent. In the challenged mice, PLCε deficiency reduced proinflammatory cytokine production in the bronchial epithelial cells. Primary-cultured bronchial epithelial cells prepared from PLCεΔX/ΔX mice showed attenuated pro-inflammatory cytokine production when stimulated with tumor necrosis factor-α, suggesting that reduced cytokine production in PLCεΔX/ΔX mice was due to cell-autonomous effect of PLCε deficiency., Conclusions: PLCε plays an important role in the pathogenesis of bronchial asthma through upregulating inflammatory cytokine production by the bronchial epithelial cells.

Innate airway hyperresponsiveness (AHR) is well modeled by two strains of rat, the hyperresponsive Fischer 344 rat and the normoresponsive Lewis rat. Arginase has been implicated in AHR associated with allergic asthma models. We addressed the role of arginase in innate AHR using the Fischer-Lewis model. In vivo arginase inhibition with N(ω)-hydroxy-nor-arginine (nor-NOHA) was evaluated on methacholine-induced bronchoconstriction in the Fischer and the Lewis rats. Arginase activity and mRNA expression were quantified in structural and resident cells of the proximal airway tree. The effect of nor-NOHA was evaluated on cultured tracheal smooth muscle proliferation. Fischer rats exhibited significantly greater changes in respiratory resistance and elastance in response to methacholine compared with Lewis rats. nor-NOHA reduced the methacholine-induced bronchoconstriction in the central airways of Lewis rats, while it did not change the innate AHR of Fischer rats. Lewis rats exhibited greater arginase activity in tracheal smooth muscle but a lower proliferation rate compared with Fischer rats. Smooth muscle proliferation was not affected by nor-NOHA in either strain of rats. The strain-specific arginase expression in the smooth muscle may contribute to the differences in sensitivity of the methacholine challenged airways of Lewis and Fischer rats to inhibition of arginase.

With a view to study the effect of genes GSTT1 and GSTM1 deletion on the non-specific bronchial hyperresponsiveness in children with neutrophilic bronchial asthma (BA) 46 school age children having neutrophilic BA (1st clinical group) and their 48 coevals with eosinophilic phenotype of the disease (2nd clinical group) were subjected to a complex examination at the pulmo-allergologic department of the regional child clinical hospital of Chernivtsi. The study proved that genotype T1+M1del was more frequently registered in patients with the neutrophilic phenotype of the disease, and genotype T1delM1del was equifrequent in patients with different types of the inflammation of the respiratory ways. In patients with neutrophilic BA and deletion polymorphism of genes GSTT1 and GSTM1, there was a tendency to decreasing of the bronchial lability index through the decrease of bronchodilation, and bronchial response to histamine occurred to be higher than in children with the absence of polymorphism of the referred genes of the xenobiotics biotransformation system.

Background: Sphingosine-1-phosphate (S1P), which is produced by 2 sphingosine kinase (SphK) isoenzymes, SphK1 and SphK2, has been implicated in IgE-mediated mast cell responses. However, studies of allergic inflammation in isotype-specific SphK knockout mice have not clarified their contribution, and the role that S1P plays in vivo in a mast cell- and IgE-dependent murine model of allergic asthma has not yet been examined., Objective: We used an isoenzyme-specific SphK1 inhibitor, SK1-I, to investigate the contributions of S1P and SphK1 to mast cell-dependent airway hyperresponsiveness (AHR) and airway inflammation in mice., Methods: Allergic airway inflammation and AHR were examined in a mast cell-dependent murine model of ovalbumin (OVA)-induced asthma. C57BL/6 mice received intranasal delivery of SK1-I before sensitization and challenge with OVA or only before challenge., Results: SK1-I inhibited antigen-dependent activation of human and murine mast cells and suppressed activation of nuclear factor κB (NF-κB), a master transcription factor that regulates the expression of proinflammatory cytokines. SK1-I treatment of mice sensitized to OVA in the absence of adjuvant, in which mast cell-dependent allergic inflammation develops, significantly reduced OVA-induced AHR to methacholine; decreased numbers of eosinophils and levels of the cytokines IL-4, IL-5, IL-6, IL-13, IFN-γ, and TNF-α and the chemokines eotaxin and CCL2 in bronchoalveolar lavage fluid; and decreased pulmonary inflammation, as well as activation of NF-κB in the lungs., Conclusion: S1P and SphK1 play important roles in mast cell-dependent, OVA-induced allergic inflammation and AHR, in part by regulating the NF-κB pathway., (Copyright © 2012 American Academy of Allergy, Asthma & Immunology. Published by Mosby, Inc. All rights reserved.)

Background: IL-4 and signal transducer and activator of transcription 6 (STAT6) play an important role in the progression of allergic airway disease (AAD) or asthma. IL-4 and STAT6 mediate T(H)2 responses in T cells and immunoglobulin class-switching to IgE in B cells. Both T(H)2 responses and IgE promote the asthmatic condition. We have previously demonstrated that poly (ADP-ribose) polymerase (PARP) 14, a member of the PARP family of proteins, regulates the transcription function of STAT6. However, the role of PARP-14 in AAD is not known., Objective: Here we investigate the role of PARP-14 and the enzyme activity associated with it in a model of AAD dependent on airway hyperresponsiveness and lung inflammation. We also elucidate the mechanism by which PARP-14 regulates AAD., Methods: The role of PARP-14 and its enzyme activity in AAD and T(H)2 differentiation were examined by using a murine model of AAD and in vitro T(H) cell differentiation., Results: PARP-14-deficient animals show reduced lung pathology and IgE levels when compared with control animals. Treating mice with a pharmacologic inhibitor for PARP activity reduced the severity of airway hyperresponsiveness and lung inflammation. Mechanistically, our data indicate that PARP-14 and its enzyme activity aid in the differentiation of T cells toward a T(H)2 phenotype by regulating the binding of STAT6 to the Gata3 promoter., Conclusion: PARP-14 and the catalytic activity associated with it promote T(H)2 differentiation and AAD in a murine model, and targeting PARP-14 might be a potential new therapy for allergic asthma., (Copyright © 2012 American Academy of Allergy, Asthma & Immunology. Published by Mosby, Inc. All rights reserved.)

Organic dust samples from swine confinement facilities elicit pro-inflammatory cytokine/chemokine release from bronchial epithelial cells and monocytes, dependent, in part, upon dust-induced activation of the protein kinase C (PKC) isoform, PKCε. PKCε is also rapidly activated in murine tracheal epithelial cells following in vivo organic dust challenges, yet the functional role of PKCε in modulating dust-induced airway inflammatory outcomes is not defined. Utilizing an established intranasal inhalation animal model, experiments investigated the biologic and physiologic responses following organic dust extract (ODE) treatments in wild-type (WT) and PKCε knock-out (KO) mice. We found that neutrophil influx increased more than twofold in PKCε KO mice following both a one-time challenge and 3 weeks of daily challenges with ODE as compared with WT mice. Lung pathology revealed increased bronchiolar and alveolar inflammation, lymphoid aggregates, and T cell influx in ODE-treated PKCε KO mice. Airway hyperresponsiveness to methacholine increased in PKCε KO + ODE to a greater magnitude than WT + ODE animals. There were no significant differences in cytokine/chemokine release elicited by ODE treatment between groups. However, ODE-induced nitric oxide (NO) production differed in that ODE exposure increased nitrate levels in WT mice but not in PKCε KO mice. Moreover, ODE failed to upregulate NO from ex vivo stimulated PKCε KO lung macrophages. Collectively, these studies demonstrate that PKCε-deficient mice were hypersensitive to organic dust exposure and suggest that PKCε is important in the normative lung inflammatory response to ODE. Dampening of ODE-induced NO may contribute to these enhanced inflammatory findings.

Objective: To determine whether a short-term protocol using subcutaneous sensitization with ovalbumin, without the use of adjuvants, would induce an eosinophilic response in the lungs of mice similar to that observed in previous, well-established protocols., Methods: Adult female BALB/c mice were randomized and divided into groups according to the number of sensitizations with ovalbumin and the number/dosage of intranasal ovalbumin challenges. The short-term protocol (10 days) consisted of one sensitization with ovalbumin and three ovalbumin challenges (100 µg). Total and differential cell counts in BAL fluid, levels of eosinophil peroxidase in lung tissue, and histopathological examination of the lungs were performed 24 h after the last ovalbumin challenge., Results: No significant differences were found among the groups regarding the variables studied. The short-term protocol, as well as the other protocols studied, induced an eosinophilic response similar to that obtained in the positive control., Conclusions: Subcutaneous sensitization with ovalbumin and without the use of adjuvants resulted in a significant allergic response in the lungs of mice, even in the short-term protocol group. Our findings suggest that this short-term protocol can be used as a first-line pre-clinical test for the study of new medications, reducing the costs and observation periods.

Protein kinase C variants (PKCs) have been involved in the control of airway smooth muscle (ASM) tone, and abnormalities in PKC-dependent signaling have been associated with respiratory diseases such as asthma. In this study, the role of atypical PKCζ in airway hyperresponsiveness was investigated, using an in-vitro model of TNFα-treated human bronchi and an in vivo guinea pig model of chronic asthma. Our results demonstrated that PKCζ-specific inhibition produced a significant increase in isoproterenol sensitivity in TNFα-treated bronchi and ovalbumin (OVA)-sensitized guinea pig bronchi. The role of epoxy-eicosanoids, known to exert anti-inflammatory effects in lung, on PKCζ expression and activity in these models was evaluated. An enhanced PKCζ protein expression was delineated in TNFα-treated bronchi when compared with control (untreated) and epoxy-eicosanoid-treated bronchi. Measurements of Ca(2+) sensitivity, performed in TNFα-treated bronchi, demonstrated that treatment with myristoylated (Myr) PKCζ peptide inhibitor resulted in significant reductions of pCa-induced tension. Epoxy-eicosanoid treatments had similar effects on Ca(2+) sensitivity in TNFα-treated bronchi. In control and epoxy-eicosanoid-treated bronchi, the phosphorylated forms of p38MAPK and CPI-17 were significantly decreased compared with the TNFα-treated bronchi. An enhanced expression of PKCζ was ascertained in our in-vivo model of allergic asthma. Hence an increased Ca(2+) sensitivity could be explained by the phosphorylation of p38-MAPK, which in turn leads to phosphorylation and activation of the CPI-17 regulatory protein. This process was reversed upon treatment with the Myr-PKCζ-peptide inhibitor. The present data provide relevant evidence regarding the role of PKCζ in human and rodent models of airways inflammation.

Purpose of Review: Exercise-induced bronchoconstriction (EIB) refers to acute airflow obstruction that is triggered by a period of physical exertion. Here we review recent findings about the epidemiology of EIB, immunopathology leading to EIB, and the latest understanding of the pathogenesis of EIB., Recent Findings: Longitudinal studies demonstrated that airway hyper-responsiveness to exercise or cold air at an early age are among the strongest predictors of persistent asthma. Patients that are susceptible to EIB have epithelial disruption and increased levels of inflammatory eicosanoids such as cysteinyl leukotrienes (CysLT)s. The leukocytes implicated in production of eicosanoids in the airways include both a unique mast cell population as well as eosinophils. A secreted phospholipase A(2) (sPLA(2)) enzyme that serves as a regulator of CysLT formation is present in increased quantities in asthma. Transglutaminase 2 (TGM2) is expressed at increased levels in asthma and serves as a regulator of secreted phospholipase A(2) group X (sPLA(2)-X). Further, sPLA(2)-X acts on target cells such as eosinophils to initiate cellular eicosanoid synthesis., Summary: Recent studies have advanced our understanding of EIB as a syndrome that is caused by the increased production of inflammatory eicosanoids. The airway epithelium may be an important regulator of the production of inflammatory eicosanoids by leukocytes.

The p21-activated protein kinases (Paks) have been implicated in the regulation of smooth muscle contractility, but the physiologic effects of Pak activation on airway reactivity in vivo are unknown. A mouse model with a genetic deletion of Pak1 (Pak1(-/-)) was used to determine the role of Pak in the response of the airways in vivo to challenge with inhaled or intravenous acetylcholine (ACh). Pulmonary resistance was measured in anesthetized mechanically ventilated Pak1(-/-) and wild type mice. Pak1(-/-) mice exhibited lower airway reactivity to ACh compared with wild type mice. Tracheal segments dissected from Pak1(-/-) mice and studied in vitro also exhibited reduced responsiveness to ACh compared with tracheas from wild type mice. Morphometric assessment and pulmonary function analysis revealed no differences in the structure of the airways or lung parenchyma, suggesting that that the reduced airway responsiveness did not result from structural abnormalities in the lungs or airways due to Pak1 deletion. Inhalation of the small molecule synthetic Pak1 inhibitor, IPA3, also significantly reduced in vivo airway responsiveness to ACh and 5-hydroxytryptamine (5-Ht) in wild type mice. IPA3 inhibited the contractility of isolated human bronchial tissues to ACh, confirming that this inhibitor is also effective in human airway smooth muscle tissue. The results demonstrate that Pak is a critical component of the contractile activation process in airway smooth muscle, and suggest that Pak inhibition could provide a novel strategy for reducing airway hyperresponsiveness.

Background: Cigarette smoke exposure is strongly associated with airway hyperreactivity (AHR) which is the main characteristic seen in asthma. The intracellular MAPK signaling pathways are suggested to be associated with the airway damage to the AHR. In the present study, we hypothesize that secondhand cigarette smoke (SHS) exposure upregulates the bronchial contractile receptors via activation of the Raf/ERK/MAPK pathway., Methodology/principal Findings: Rats were exposed to SHS for 3 h daily for up to 8 weeks. The receptor agonists-induced bronchial contractile reactivity was analyzed with a sensitive myograph system. The mRNA transcription and protein translation of the target receptors and the kinases in Raf/ERK/MAPK pathway were investigated by real-time PCR, Western blotting and immunofluorescence, respectively. Compared with exposure to fresh air, SHS induced enhanced bronchial contractile responses mediated by the 5-hydroxytryptamine 2A (5-HT(2A)) receptors as well as the endothelin type B (ET(B)) and type A (ET(A)) receptors. The response curves were shifted toward the left with an increased maximal contraction (E(max)) demonstrating that SHS induced AHR. Additionally, the mRNA and protein levels of the 5-HT(2A), ET(B) and ET(A) receptors were increased. Furthermore, SHS exposure increased the phosphorylation of Raf-1 and ERK1/2, but it did not alter p38 or JNK. A Raf-1 inhibitor (GW5074) suppressed the SHS-induced increase in the expression of 5-HT(2A) and ET(A) receptors and the receptor-mediated AHR., Conclusions/significance: Our findings show that SHS exposure induces transcriptional upregulation of the 5-HT(2A), ET(B) and ET(A) receptors in rat bronchial smooth muscle cells, which mediates AHR. The Raf/ERK/MAPK pathway is involved in SHS-associated receptor upregulation and AHR.

Secretory leukocyte protease inhibitor (SLPI) is an anti-inflammatory protein that is observed at high levels in asthma patients. Resiquimod, a TLR7/8 ligand, is protective against acute and chronic asthma, and it increases SLPI expression of macrophages in vitro. However, the protective role played by SLPI and the interactions between the SLPI and resiquimod pathways in the immune response occurring in allergic asthma have not been fully elucidated. To evaluate the role of SLPI in the development of asthma phenotypes and the effect of resiquimod treatment on SLPI, we assessed airway resistance and inflammatory parameters in the lungs of OVA-induced asthmatic SLPI transgenic and knockout mice and in mice treated with resiquimod. Compared with wild-type mice, allergic SLPI transgenic mice showed a decrease in lung resistance (p < 0.001), airway eosinophilia (p < 0.001), goblet cell hyperplasia (p < 0.001), and plasma IgE levels (p < 0.001). Allergic SLPI knockout mice displayed phenotype changes significantly more severe compared with wild-type mice. These phenotypes included lung resistance (p < 0.001), airway eosinophilia (p < 0.001), goblet cell hyperplasia (p < 0.001), cytokine levels in the lungs (p < 0.05), and plasma IgE levels (p < 0.001). Treatment of asthmatic transgenic mice with resiquimod increased the expression of SLPI and decreased inflammation in the lungs; resiquimod treatment was still effective in asthmatic SLPI knockout mice. Taken together, our study showed that the expression of SLPI protects against allergic asthma phenotypes, and treatment by resiquimod is independent of SLPI expression, displayed through the use of transgenic and knockout SLPI mice.

The competition between arginases and NO synthases (NOS) for their common substrate L-arginine can be important in the airways hyperreactivity. We investigated the effect of the simultaneous modulation of arginase and NOS activities in allergen-induced airways hyperreactivity. We analysed the response of tracheal and lung tissue smooth muscle to histamine or acetylcholine after administration N(ω)-nitro-L-arginine methyl ester (L-NAME), aminoguanidine (AG) and N(ω)-hydroxy-L-arginine (NOHA) in the combinations in in vitro conditions. The results show the decrease of ovalbumin-induced hyperreactivity after inhibition of arginase activity with NOHA. A supplementation of L-arginine caused favourable effect on the airway smooth muscle response. We found the airway reactivity decrease on the whole if we used the combination of NOS and arginase inhibitors. The inhibition of both types of enzymes caused more expressive effect in tracheal smooth muscles. We recorded the difference in the response to histamine or acetylcholine. The simultaneous inhibition of iNOS (with AG) and arginase (with NOHA) evoked the most expressive effect. Results show the importance of competition of both types enzymes - NOS and arginase for the balance of theirs activities in the control of airways bronchomotoric tone in the conditions of the airways hyperreactivity.

We have shown that proteinase-activated receptor-2 (PAR(2)) activation in the airways leads to allergic sensitization to concomitantly inhaled Ags, thus implicating PAR(2) in the pathogenesis of asthma. Many aeroallergens with proteinase activity activate PAR(2). To study the role of PAR(2) in allergic sensitization to aeroallergens, we developed a murine model of mucosal sensitization to cockroach proteins. We hypothesized that PAR(2) activation in the airways by natural allergens with serine proteinase activity plays an important role in allergic sensitization. Cockroach extract (CE) was administered to BALB/c mice intranasally on five consecutive days (sensitization phase) and a week later for four more days (challenge phase). Airway hyperresponsiveness (AHR) and allergic airway inflammation were assessed after the last challenge. To study the role of PAR(2), mice were exposed intranasally to a receptor-blocking anti-PAR(2) Ab before each administration of CE during the sensitization phase. Mucosal exposure to CE induced eosinophilic airway inflammation, AHR, and cockroach-specific IgG1. Heat-inactivated or soybean trypsin inhibitor-treated CE failed to induce these effects, indicating that proteinase activity plays an important role. The use of an anti-PAR(2) blocking Ab during the sensitization phase completely inhibited airway inflammation and also decreased AHR and the production of cockroach-specific IgG1. PAR(2) activation by CE acts as an adjuvant for allergic sensitization even in the absence of functional TLR4. We conclude that CE induces PAR(2)-dependent allergic airway sensitization in a mouse model of allergic airway inflammation. PAR(2) activation may be a general mechanism used by aeroallergens to induce allergic sensitization.

Background: Arginase overexpression contributes to airways hyperresponsiveness (AHR) in asthma. Arginase expression is further augmented in cigarette smoking asthmatics, suggesting that it may be upregulated by environmental pollution. Thus, we hypothesize that arginase contributes to the exacerbation of respiratory symptoms following exposure to air pollution, and that pharmacologic inhibition of arginase would abrogate the pollution-induced AHR., Methods: To investigate the role of arginase in the air pollution-induced exacerbation of airways responsiveness, we employed two murine models of allergic airways inflammation. Mice were sensitized to ovalbumin (OVA) and challenged with nebulized PBS (OVA/PBS) or OVA (OVA/OVA) for three consecutive days (sub-acute model) or 12 weeks (chronic model), which exhibit inflammatory cell influx and remodeling/AHR, respectively. Twenty-four hours after the final challenge, mice were exposed to concentrated ambient fine particles plus ozone (CAP+O₃), or HEPA-filtered air (FA), for 4 hours. After the CAP+O₃ exposures, mice underwent tracheal cannulation and were treated with an aerosolized arginase inhibitor (S-boronoethyl-L-cysteine; BEC) or vehicle, immediately before determination of respiratory function and methacholine-responsiveness using the flexiVent®. Lungs were then collected for comparison of arginase activity, protein expression, and immunohistochemical localization., Results: Compared to FA, arginase activity was significantly augmented in the lungs of CAP+O₃-exposed OVA/OVA mice in both the sub-acute and chronic models. Western blotting and immunohistochemical staining revealed that the increased activity was due to arginase 1 expression in the area surrounding the airways in both models. Arginase inhibition significantly reduced the CAP+O₃-induced increase in AHR in both models., Conclusions: This study demonstrates that arginase is upregulated following environmental exposures in murine models of asthma, and contributes to the pollution-induced exacerbation of airways responsiveness. Thus arginase may be a therapeutic target to protect susceptible populations against the adverse health effects of air pollution, such as fine particles and ozone, which are two of the major contributors to smog.

Vasoactive intestinal peptide (VIP) is a neuropeptide with cytokine properties that is abundant in the lung. VIP null mice exhibit spontaneous airway inflammation and hyperresponsiveness emphasizing VIP's "anti-asthma" potential. Although VIP's impending protective role in the lung has been demonstrated, its localization in the naïve and allergic murine lungs has not. To this aim, we analyzed the availability of VIP and its protease, neutral peptidase (NEP), in naïve and Aspergillus-sensitized and challenged murine lungs after 3, 7, and 14days. Both VIP and NEP were predominantly localized to the columnar epithelia of the airways in naïve lungs. A marked decrease in VIP occurred in these cells 3days after allergen challenge. NEP localization in the columnar epithelia decreased after allergen challenge. At day 14, VIP localization in the columnar epithelia and arteriolar smooth muscle increased while NEP localization at these sites remained low. This study provides new insights into the local regulation of VIP in the columnar epithelia of the allergic lung. Its altered availability in the context of allergy provides fresh evidence for the modulation of pulmonary inflammation by VIP., (Copyright 2010 Elsevier B.V. All rights reserved.)

IkappaB kinase (IKK)-mediated intracellular signaling mechanisms may be involved in airway hyperresponsiveness through up-regulation of bradykinin receptors. This study was designed to examine if organ culture of rat bronchial segments induces airway hyperresponsiveness to bradykinin and if inhibition of IKK can abrogate the airway hyperresponsiveness to bradykinin via suppressing the expression of bradykinin B1 and B2 receptors. Rat bronchi were isolated and cut into ring segments. The segments were then organ cultured in the presence or absence of IKK inhibitors, BMS-345541 or TPCA-1. des-Arg9-bradykinin (B1 receptor agonist)--and bradykinin (B(2) receptor agonist)--induced contractions of the segments were monitored by a sensitive organ bath system. The expression of bradykinin B1 and B2 receptors, inflammatory mediators and phosphorylated IKK were studied by a real-time PCR and/or by immunohistochemistry using confocal microscopy. Organ culture of the bronchial segments induced a time-dependent up-regulation of bradykinin B1 and B2 receptors. The IKK inhibitors abolished the organ culture-induced up-regulation of bradykinin B1 and B2 receptor-mediated contractions in a concentration-dependent manner. This was paralleled with inhibition of IKK activity (phosphorylation), reduced mRNA and protein expressions of bradykinin B1 and B2 receptors and decreased mRNA expression of inflammatory mediators (interleukin-6, inducible nitric oxide synthase, cyclooxygenase 2 and matrix metalloproteinase 9). Our results show that organ culture induces IKK-mediated inflammatory changes in airways which subsequently results in airway hyperresponsiveness to bradykinin via the up-regulated bradykinin receptors. Thus, IKK inhibition might be a promising approach for treatment of airway inflammation and airway hyperresponsiveness that are often seen in asthmatic patients., (Copyright 2010 Elsevier B.V. All rights reserved.)

It is widely established that mast cells (MCs) have a harmful role in asthma, for example by secreting various proinflammatory substances stored within their secretory granule. However, in this study, we show that one of the substances stored within MC granule, chymase, in fact has a protective role in allergic airway inflammation, indicating that MCs may possess both harmful and protective activities in connection with this type of disease. Wild-type (WT) mice and mice lacking mouse MC protease 4 (mMCP-4), a chymase that is functionally homologous to human chymase, were sensitized and challenged with OVA, followed by the assessment of airway physiology and inflammatory parameters. Our results show that the airway hyperresponsiveness was significantly higher in mMCP-4(-/-) as compared with WT mice. Moreover, the degree of lung tissue inflammation was markedly higher in mice lacking mMCP-4 than in WT controls. Histological analysis revealed that OVA sensitization/challenge resulted in a marked increased in the thickness of the smooth muscle cell (SMC) layer and, notably, that the degree of SMC layer thickening was more pronounced in mMCP-4(-/-) animals than in WT controls, thus indicating that chymase may have an effect on airway SMCs. In support of this, mMCP-4-positive MCs were located in the close vicinity of the SMC layer, mainly in the upper airways, and mMCP-4 was shown to be the major chymase expressed in these MCs. Taken together, our results indicate that chymase present in the upper airways protects against allergic airway responses, possibly by regulating SMCs.

Recent studies revealed an involvement of RhoA/Rho-kinase in the contraction of bronchial smooth muscle (BSM), and this pathway has now been proposed as a new target for asthma therapy. A posttranslational geranylgeranylation of RhoA is required for its activation. Thus selective inhibition of geranylgeranyltransferase may be a novel strategy for treatment of the BSM hyperresponsiveness in asthmatics. To test this hypothesis, we investigated the effect of a geranylgeranyltransferase inhibitor, GGTI-2133, on antigen-induced BSM hyperresponsiveness by using mice with experimental asthma. Mice were sensitized and repeatedly challenged with ovalbumin antigen. Animals also were treated with GGTI-2133 (5 mg/kg ip) once a day before and during the antigen inhalation period. Repeated antigen inhalation caused a BSM hyperresponsiveness to acetylcholine with the increased expressions of RhoA and the anti-farnesyl-positive 21-kDa proteins, probably geranylgeranylated RhoA. The in vivo GGTI-2133 treatments significantly inhibited BSM hyperresponsiveness induced by antigen exposure. In another series of experiments, BSM tissues isolated from the repeatedly antigen-challenged mice were cultured for 48 h in the absence or presence of GGTI-2133. Under these conditions, the putative geranylgeranylated RhoA was decreased in a GGTI-2133 concentration-dependent manner. The in vitro incubation with GGTI-2133 also inhibited BSM hyperresponsiveness induced by antigen exposure. These findings suggest that GGTI-2133 inhibits antigen-induced BSM hyperresponsiveness, probably by reducing downstream signal transduction of RhoA. Selective geranylgeranyltransferase inhibitors may be beneficial for the treatment of airway hyperresponsiveness, one of the characteristic features of allergic bronchial asthma.

Allergic asthma is a chronic inflammatory airways' disease, characterized by allergen-induced early and late bronchial obstructive reactions, airway hyperresponsiveness (AHR), airway inflammation and airway remodelling. Recent ex vivo and in vivo studies in animal models and asthmatic patients have indicated that arginase may play a central role in all these features. Thus, increased arginase activity in the airways induces reduced bioavailability of L-arginine to constitutive (cNOS) and inducible (iNOS) nitric oxide synthases, causing a deficiency of bronchodilating and anti-inflammatory NO, as well as increased formation of peroxynitrite, which may be involved in allergen-induced airways obstruction, AHR and inflammation. In addition, both via reduced NO production and enhanced synthesis of L-ornithine, increased arginase activity may be involved in airway remodelling by promoting cell proliferation and collagen deposition in the airway wall. Therefore, arginase inhibitors may have therapeutic potential in the treatment of acute and chronic asthma. This review focuses on the pathophysiological role of arginase in allergic asthma and the emerging effectiveness of arginase inhibitors in the treatment of this disease.

One host susceptibility factor for ozone identified in epidemiologic studies is NAD(P)H quinone oxidoreductase 1 (NQO1). We hypothesized that after ozone exposure, NQO1 is required to increase 8-isoprostane (also known as F(2)-isoprostane) production, a recognized marker of ozone-induced oxidative stress, and to enhance airway inflammation and hyperresponsiveness. In this report, we demonstrate that in contrast to wild-type mice, NQO1-null mice are resistant to ozone and have blunted responses, including decreased production of F(2)-isoprostane and keratinocyte chemokine, decreased airway inflammation, and diminished airway hyperresponsiveness. Importantly, these results in mice correlate with in vitro findings in humans. In primary human airway epithelial cells, inhibition of NQO1 by dicumarol blocks ozone-induced F(2)-isoprostane production and IL-8 gene expression. Together, these results demonstrate that NQO1 modulates cellular redox status and influences the biologic and physiologic effects of ozone.

Eosinophil counts in the bronchoalveolar lavage fluid of wild-type (WT) mice increased after ovalbumin (OVA) challenge, a response that was diminished in comparably challenged low-expressing coagulation factor VII (FVII(tTA/tTA)) mice. Levels of T helper type 2 (Th2) cytokines, IL-4, IL-5, and IL-13, and eosinophil-attracting chemokines, eotaxin and RANTES, were also lower in the OVA-challenged FVII(tTA/tTA) mice. Eosinophils purified from low-FVII mice underwent apoptosis at a faster rate compared with WT eosinophils, and eosinophil migration in response to eotaxin was reduced in eosinophils obtained from FVII(tTA/tTA) mice. Airway hyperresponsiveness and mucous layer thickness were reduced in OVA-treated FVII(tTA/tTA) mice, and addition of exogenous coagulation factor X (FX) enhanced mucin production in human epithelial NCI-H292 cells. Correspondingly, incubation of FX with NCI-H292 cells resulted in activated (a) FX production, suggesting that the components required for FX activation were present on NCI-H292 cells. These results demonstrate that FVIIa functions in the asthmatic response to an allergen by stimulating lung eosinophilia, airway hyperresponsiveness, and mucin production, this latter effect through its ability to activate FX in conjunction with tissue factor.

Oxidative stress is an important causative factor in the onset and progression of smoking-related lung diseases, such as chronic obstructive pulmonary disease (COPD). Superoxide dismutases (SODs) can prevent an increase in oxidative burden. A total of 1,390 subjects from the prospective Vlagtwedde-Vlaardingen cohort were genotyped for two single nucleotide polymorphisms (SNPs) in SOD2 and four SNPs in SOD3, which were further analysed for associations with the presence of bronchial hyperresponsiveness (BHR; provocative concentration causing a 10% fall in the forced expiratory volume in one second (FEV(1); PC(10)

Endothelial lipase (EL) is a novel phospholipase that determines plasma high-density lipoprotein cholesterol (HDL-C) levels. We have investigated the role of HDL-C in lung allergic inflammation by using EL knockout (EL-KO) mice that are high in HDL-C. EL-KO and wild-type control mice were sensitized and challenged with ovalbumin to evoke eosinophilic inflammation in the lung. EL was expressed in epithelial cells, alveolar type II cells, and endothelial cells in the lung, and its expression was upregulated during inflammation. Concomitant with attenuated hyperresponsiveness of the airway smooth muscles, the number of eosinophils in bronchoalveolar lavage and the expression of VCAM-1 were lower in EL-KO mice than in control mice. HDL reduced cytokine-induced VCAM-1 expression in cultured endothelial cells. When plasma HDL levels were decreased to similar levels in both mouse groups by adenovirus-mediated overexpression of EL, however, eosinophil infiltration was still lower in EL-KO mice. In vitro adhesion assays revealed that EL expression on the cell surface promoted the interaction of eosinophils through the ligand-binding function of EL. In summary, targeted inactivation of EL attenuated allergic inflammation in the lung, and the protective effects in EL-KO mice were associated with high plasma HDL levels, downregulation of VCAM-1, and loss of the direct ligand-binding function of EL. Thus EL is a novel modulator of the progression of allergic asthma.

Arginase has been suggested to compete with nitric oxide synthase (NOS) for their common substrate, l-arginine. To study the mechanisms underlying this interaction, we compared arginase expression in isolated airways and the consequences of inhibiting arginase activity in vivo with NO production, lung inflammation, and lung function in both C57BL/6 and NOS2 knockout mice undergoing ovalbumin-induced airway inflammation, a mouse model of asthma. Arginases I and II were measured by western blot in isolated airways from sensitized C57BL/6 mice exposed to ovalbumin aerosol. Physiological and biochemical responses - inflammation, lung compliance, airway hyperreactivity, exhaled NO concentration, arginine concentration - were compared with the responses of NOS2 knockout mice. NOS2 knockout mice had increased total cells in lung lavage, decreased lung compliance, and increased airway hyperreactivity. Both arginase I and arginase II were constitutively expressed in the airways of normal C57BL/6 mice. Arginase I was up-regulated approximately 8-fold in the airways of C57BL/6 mice exposed to ovalbumin. Expression of both arginase isoforms were significantly upregulated in NOS2 knockout mice exposed to ovalbumin, with about 40- and 4-fold increases in arginases I and II, respectively. Arginine concentration in isolated airways was not significantly different in any of the groups studied. Inhibition of arginase by systemic treatment of C57BL/6 mice with a competitive inhibitor, Nomega-hydroxy-nor-l-arginine (nor-NOHA), significantly decreased the lung inflammatory response to ovalbumin in these animals. We conclude that NOS2 knockout mice are more sensitive to ovalbumin-induced airway inflammation and its sequelae than are C57BL/6 mice, as determined by increased total cells in lung lavage, decreased lung compliance, and increased airway hyperreactivity, and that these findings are strongly correlated with increased expression of both arginase isoforms in the airways of the NOS2 knockout mice exposed to ovalbumin.

Adenosine is formed from extracellular purines by ecto-5'-nucleotidase (CD73) and is an essential player in allergic airway inflammation. The contribution of adenosine and other purines to electrolyte transport and mucociliary clearance was studied in airways of allergen challenged mice. No signs for allergen-induced inflammation were found in CD73-/- mice, and adenosine monophosphate (AMP) was unable to elicit airway Cl(-) secretion in these animals. Tracheas of ovalbumin (OVA)-treated BALB/c and CD73+/+ mice were hyperresponsive towards methacholine when assessed by Penh and direct optical measurement of contraction. In addition Cl(-) secretion activated by ATP and ADP was enhanced. These changes were not observed in CD73-/- mice. Expression of CFTR or CLCA was unchanged upon OVA treatment of CD73 mice, suggesting enhanced Cl(-) secretion due to upregulated purinergic pathways. Mucociliary clearance was determined by measuring particle transport in excised mouse tracheas and was strongly enhanced in OVA-challenged CD73+/+ mice, but remained unchanged in CD73-/- mice. While mucociliary clearance is activated by allergen exposure independent of functional ecto-5'-nucleotidase, airway inflammation is largely dependent on CD73. Thus, ecto-5'-nucleotidase may provide a novel target for therapeutic intervention, probably by local application of ecto-5'-nucleotidase inhibitors through inhalation.

Background and Purpose: M2-type pyruvate kinase (M2PK) was found to interact directly with the 'ITAM' region of the gamma chain of the high-affinity IgE receptor (FcvarepsilonRI). Our hypothesis was that mast cell degranulation might require the FcvarepsilonRI-mediated inhibition of M2PK activity., Experimental Approach: In rat basophilic leukaemia (RBL-2H3) cells, the effects of directly inhibiting M2PK or preventing the FcvarepsilonRI-mediated inhibition of M2PK (disinhibition) on degranulation was measured by hexosaminidase release. Effects of blocking the FcvarepsilonRI-mediated inhibition of M2PK was also assessed in vivo in a mouse model of allergen-induced airway hyper-responsiveness., Key Results: Activation of FcvarepsilonRI in RBL-2H3 cells caused the rapid phosphorylation of tyrosine residues in M2PK, associated with a decrease in M2PK enzymatic activity. There was an inverse correlation between M2PK activity and mast cell degranulation. FcvarepsilonRI-mediated inhibition of M2PK involved Src kinase, phosphatidylinositol 3-kinase, PKC and calcium. Direct inhibition of M2PK potentiated FcvarepsilonRI-mediated degranulation and prevention of the FcvarepsilonRI-mediated inhibition of M2PK attenuated mast cell degranulation. Transfection of RBL-2H3 cells with M1PK which prevents FcvarepsilonRI-induced inhibition of M2PK, markedly reduced their degranulation and exogenous M1PK (i.p.) inhibited ovalbumin-induced airway hyper-responsiveness in vivo., Conclusions and Implications: We have identified a new control point and a novel biochemical pathway in the process of mast cell degranulation. Our study suggests that the FcvarepsilonRI-mediated inhibition of M2PK is a crucial step in responses to allergens. Moreover, the manipulation of glycolytic processes and intermediates could provide novel strategies for the treatment of allergic diseases.

The Tec family tyrosine kinase, IL-2-inducible T cell kinase (Itk), is expressed in T cells and mast cells. Mice lacking Itk exhibit impaired Th2 cytokine secretion; however, they have increased circulating serum IgE, but exhibit few immunological symptoms of allergic airway responses. We have examined the role of Itk in mast cell function and FcepsilonRI signaling. We report in this study that Itk null mice have reduced allergen/IgE-induced histamine release, as well as early airway hyperresponsiveness in vivo. This is due to the increased levels of IgE in the serum of these mice, because the transfer of Itk null bone marrow-derived cultured mast cells into mast cell-deficient W/W(v) animals is able to fully rescue histamine release in the W/W(v) mice. Further analysis of Itk null bone marrow-derived cultured mast cells in vitro revealed that whereas they have normal degranulation responses, they secrete elevated levels of cytokines, including IL-13 and TNF-alpha, particularly in response to unliganded IgE. Analysis of biochemical events downstream of the FcepsilonRI revealed little difference in overall tyrosine phosphorylation of specific substrates or calcium responses; however, these cells express elevated levels of NFAT, which was largely nuclear. Our results suggest that the reduced mast cell response in vivo in Itk null mice is due to elevated levels of IgE in these mice. Our results also suggest that Itk differentially modulates mast cell degranulation and cytokine production in part by regulating expression and activation of NFAT proteins in these cells.

Airway hyperresponsiveness (AHR) is a hallmark of bronchial asthma. Increased expression of smooth muscle contractile proteins or increased responsiveness of the contractile apparatus due to RhoA/Rho-kinase activation may contribute to AHR. BALB/c mice developed AHR following systemic sensitization by intraperitoneal injections of 20 microg ovalbumin (OVA) in presence of 2mg Al(OH)(3) on days 1 and 14, and airway challenge by 1% OVA-inhalation for 20 min each on days 28, 29 and 30. As assessed by Western blot, protein expression of RhoA, MLC (myosin light chain) and smMLCK (smooth muscle myosin light chain kinase) was increased in lungs of OVA/OVA-animals with AHR, as well as in lungs of OVA-sensitized and sham-challenged animals (OVA/PBS) without AHR, compared with lungs of PBS/PBS-animals. Pretreatment with the specific Rho-kinase inhibitor Y-27632 reduced MLC-phosphorylation and AHR. Contribution of Rho-kinase to bronchoconstriction was increased in lungs of OVA/OVA-animals compared with OVA/PBS- and PBS/PBS-animals, respectively. Furthermore, bronchoconstriction following MCh stimulation was significantly reduced after Y-27632 application. In conclusion, systemic allergen-sensitization increased pulmonary expression of proteins involved in smooth muscle contraction, which may contribute to development of AHR. However, this observation was independent from local allergen challenge, suggesting that additional cofactors may be required for the activation of Rho-kinase and thereby the induction of AHR. Rho-kinase may play an important role in murine AHR, and the bronchodilating action of Rho-kinase inhibition may offer a new therapeutic perspective in obstructive airway disease.

Indoleamine 2,3 dioxygenase (IDO) has emerged as an important mediator of immune tolerance via inhibition of Th1 responses. However, the role of IDO in antigen-induced tolerance or allergic inflammation in the airways that is regulated by Th2 responses has not been elucidated. By using IDO(-/-) mice, we found no impairment of airway tolerance, but, surprisingly, absence of IDO provided significant relief from establishment of allergic airways disease, as evident from attenuated Th2 cytokine production, airway inflammation, mucus secretion, airway hyperresponsiveness, and serum ovalbumin-specific IgE. Myeloid dendritic cells isolated from lung-draining lymph nodes of mice immunized for either Th1 or Th2 response revealed fewer mature dendritic cells in the lymph nodes of IDO(-/-) mice. However, the net functional impact of IDO deficiency on antigen-induced responses was more remarkable in the Th2 model than in the Th1 model. Collectively, these data suggest that IDO is not required for the induction of immune tolerance in the airways but plays a role in promoting Th2-mediated allergic airway inflammation via unique effects on lung dendritic cells.

The Th2 cytokine interleukin (IL) 13 can elicit a number of responses consistent with a key role in the pathogenesis of asthma. We have used pharmacological and genetic approaches to demonstrate the role of signaling via the class I phosphoinositide 3-kinase p110delta isoform in IL-13-induced hyper-responsiveness of murine tracheal smooth muscle contractility in vitro. IL-13 treatment of tracheal tissue is associated with an early activation of phosphoinositide 3-kinase (PI3K), as assessed by phosphorylation of Akt. Tracheal smooth muscle contractility is enhanced by overnight incubation with IL-13, resulting in increased maximal contractions (E(max)) to carbachol (CCh) and KCl. Inhibition of PI3K by the non-isoform-selective inhibitors wortmannin or 2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one (LY294002), or the selective inhibitor of the PI3K p110delta isoform 2-(6-aminopurin-9-ylmethyl)-5-methyl-3-O-tolyl-3H-quinazolin-4-one (IC87114), prevented IL-13-induced hyper-responsiveness. Consistent with a role for PI3K p110delta in IL-13-induced hyper-responsiveness, IL-13 was unable to induce hyper-responsiveness in tissues from mice expressing the catalytically inactive form of p110delta (p110delta(D910A)). These data indicate that IL-13 contributes to tracheal smooth muscle hyper-responsiveness via the PI3K p110delta isoform. In addition to previously reported effects on airway inflammation, inhibition of PI3K p110delta may be a useful target for the treatment of asthma by preventing IL-13-induced airway smooth muscle hyper-responsiveness.

Background: Allergic bronchial asthma is a chronic inflammatory disease of the airways. The transcription factor GATA-3 was shown to play an important role in TH2 cell activation, but also in the regulation of other cell types involved in bronchial asthma including mast cells, eosinophils, and epithelial cells. DNAzymes represent a new class of antisense molecules that combines the specificity of DNA base pairing with an inherent RNA-cleaving enzymatic activity., Objective: To develop a GATA-3 mRNA-specific DNAzyme and analyze its allergy-preventing activity in murine models of experimental allergic asthma., Methods: The most active DNAzyme (termed gd21) was selected by in vitro cleavage assays. Allergic airway inflammation was assessed by inflammatory cell and cytokine analysis within bronchoalveolar lavage. Lung histology, including goblet cell hyperplasia and lung function, was analyzed using head-out body-plethysmography., Results: Intranasal administration of gd21 prevented airway inflammation and mucus production and inhibited development of airway hyperresponsiveness to methacholine in models of acute allergic airway inflammation. Similar effects were also detected in a model of chronic experimental asthma. Interestingly, gd21 was at least as effective as other antisense molecules, and off-target effects were not detected. Further experiments indicated that pulmonary surfactant may facilitate the cellular uptake of gd21 by acting as an endogenous transfectant., Conclusion: These results indicate that topical application of the GATA-3-specific DNAzyme is a promising novel approach for the treatment of allergic bronchial asthma.

Background: Bronchial hyperresponsiveness (BHR) and variation in glutathione S-transferase (GST) genes have been associated with asthma risk. The relationship of these two risk factors with adult onset asthma in the general population was investigated., Methods: GSTP1 Ile105Val single nucleotide polymorphism and GSTM1 and GSTT1 gene deletion polymorphisms were genotyped in the population-representative SAPALDIA cohort. BHR was assessed at baseline by methacholine challenge and defined as a fall of > or =20% in forced expiratory volume in 1 s. Independent effects of GST polymorphisms and BHR on new onset of asthma after 11 years of follow-up were estimated by multiple logistic regression analysis, adjusting for relevant baseline measures. Effect modification was assessed by including interaction terms in the model., Results: Among 4426 asthma-free participants at baseline, 14% had BHR. At follow-up, 3.3% reported new onset of physician-diagnosed asthma. BHR (p<0.001) and GSTP1 Ile105Val genotype (p = 0.005) were independently associated with incident asthma, but no association was seen for GSTT1 and GSTM1 gene deletion polymorphisms. Among subjects free of respiratory symptoms at baseline, the effect of BHR on the risk of physician-diagnosed asthma at follow-up was restricted to GSTP1 105 Ile/Ile carriers (OR 4.57, 95% CI 2.43 to 8.57 vs 1.40, 95% CI 0.58 to 3.39; p for interaction = 0.023)., Conclusions: If confirmed by independent studies, our results suggest that GSTP1 Ile105Val genotype strongly determines the progression of BHR to physician-diagnosed asthma in the general population.

To determine the mechanism(s) of the inhibitory effect of glucocorticoids on airway hyperresponsiveness in allergic bronchial asthma, the effects of systemic treatment with glucocorticoids on bronchial smooth muscle hyperresponsiveness and RhoA upregulation were investigated in rats with allergic bronchial asthma. Rats were sensitized and repeatedly challenged with 2,4-dinitrophenylated Ascaris suum antigen. Animals were also treated with prednisolone or beclomethasone (each 10 mg/kg, i.p.) once a day during the antigen inhalation period. Repeated antigen inhalation caused a marked bronchial smooth muscle hyperresponsiveness to acetylcholine with an upregulation of RhoA. Augmented acetylcholine-induced activation of RhoA and phosphorylation of myosin light chain were observed in bronchial smooth muscles of the antigen-exposed animals. Systemic treatment with either glucocorticoid used inhibited the bronchial smooth muscle hypercontraction until the level of the sensitized control rats that received saline inhalation instead of antigen challenge. Interestingly, both glucocorticoids also inhibited the upregulation of RhoA and augmented acetylcholine-induced activation of RhoA and phosphorylation of myosin light chain. In conclusion, glucocorticoids ameliorated the augmented bronchial smooth muscle contraction by inhibiting upregulation of RhoA. These effects of glucocorticoids may account for, in part, their beneficial effects in the treatment of asthma.

Allergic asthma is dependent on chemokine-mediated Th2 cell migration and Th2 cytokine secretion into the lungs. The inducible T cell tyrosine kinase Itk regulates the production of Th2 cytokines as well as migration in response to chemokine gradients. Mice lacking Itk are resistant to developing allergic asthma. However, the role of kinase activity of Itk in the development of this disease is unclear. In addition, whether distinct Itk-derived signals lead to T cell migration and secretion of Th2 cytokines is also unknown. Using transgenic mice specifically lacking Itk kinase activity, we show that active kinase signaling is required for control of Th2 responses and development of allergic asthma. Moreover, dominant suppression of kinase Itk activity led to normal Th2 responses, but significantly reduced chemokine-mediated migration, resulting in prevention of allergic asthma. These observations indicate that signals required for Th2 responses and migration are differentially sensitive to Itk activity. Manipulation of Itk's activity can thus provide a new strategy to treat allergic asthma by differentially affecting migration of T cells into the lungs, leaving Th2 responses intact.

Chronic obstructive pulmonary disease (COPD) is the 5(th) most prevalent disease worldwide leading to severe morbidity and mortality in developed countries. The disease is strongly associated with smoking, and can be characterized by progressive and irreversible deterioration in lung function and destruction of the lung parenchyma. We show here that infection with the hookworm Nippostrongylus brasiliensis results in deterioration in lung function, destruction of alveoli and long-term airways hyperresponsiveness, consistent with COPD and emphysema. N. brasiliensis infection leads to chronic low level hemorrhaging in the lung and the presence of hemosiderin-laden macrophages in the absence of an overt inflammatory infiltrate. Microarray analysis of gene expression in diseased lungs and quantitative RT-PCR analysis of purified macrophages revealed a state of prolonged tissue injury and the presence of alternatively activated macrophages producing MMP-12. Taken together, these data show that lung tissue damage caused by hookworm infection can result in the development of COPD and emphysema.

Background: Decreased dipeptidylpeptidase IV (DPPIV) activity within the human nasal mucosa has previously been shown to contribute to the severity of chronic inflammatory rhinosinusitis., Objective: To investigate and correlate the role of DPPIV activity with regard to bronchial inflammation., Methods: DPPIV/CD26 activity/concentration was investigated in the bronchial tissue of human subjects suffering from chronic bronchial inflammation. In addition, the effect of a recombinant Aspergillus fumigatus DPPIV (fuDPPIV) was investigated on histamine-induced bronchoconstriction in anesthetized rabbits., Results and Conclusions: DPPIV/CD26 was present in submucosal seromucous glands, in leukocytes and to a very low degree in endothelial cells of human bronchi. DPPIV activity was correlated with tissue CD26 content measured by immunoassay. As previously reported for the nasal mucosa, DPPIV/CD26 activity was inversely correlated with the degree of airway inflammation. Systemic pretreatment with recombinant fuDPPIV markedly reduced the increase in histamine-induced airway resistance in rabbits. In conclusion, DPPIV activity modulates lower airway tone by degrading unknown peptidic substrates released by histamine in response to an allergen. Contrasting with our observations in the nose, this modulation is apparently not mediated via a neurokinin (NK1) receptor., ((c) 2007 S. Karger AG, Basel.)

beta-Tryptase, a product of the TPSAB1 and TPSB2 genes, is a trypsin-like serine protease that is a major and selective component of the secretory granules of all human mast cells, accounting for as much as 25% of cell protein. Once mast cells are activated, beta-tryptase is released along with histamine and heparin proteoglycan. beta-Tryptase is a unique enzyme with a homotetrameric structure in which active sites face into the central cavity of the four monomers, stabilized by heparin-proteoglycan. This structure makes beta-tryptase resistant to most biological inhibitors of serine proteases. Without stabilization, at neutral pH beta-tryptase converts to inactive monomers. Tryptase levels are elevated in bronchoalveolar lavage (BAL) fluid obtained from atopic asthmatics and in serum during systemic anaphylactic shock. Several synthetic small molecular weight beta-tryptase inhibitors reduced Ag-induced airway hypersensitivity in animals, suggesting that beta-tryptase is involved in the pathogenesis of airway inflammation. Although the major biologic substrate(s) of beta-tryptase remain ambiguous, the protease can digest several proteins of potential biologic importance, including fibrinogen, fibronectin, pro-urokinase, pro-matrix metalloprotease-3 (proMMP-3), protease activated receptor-2 (PAR2) and complement component C3. Recently, monomers of beta-tryptase with enzymatic activity have been detected in vitro. Here we discuss how beta-tryptase monomers with enzymatic activity were identified as well as their potential role in vivo.

Rationale: Secreted phospholipase A(2) enzymes (sPLA(2)s) play key regulatory roles in the biosynthesis of eicosanoids, such as the cysteinyl leukotrienes, but the role of these enzymes in the pathogenesis of asthma is not known., Objectives: To establish if sPLA(2)s are overexpressed in the airways of patients with asthma, and to determine if these enzymes may play a role in the generation of eicosanoids in exercise-induced bronchoconstriction., Methods: Induced sputum samples were obtained from subjects with asthma with exercise-induced bronchoconstriction and nonasthmatic control subjects at baseline, and on a separate day 30 minutes after exercise challenge. The expression of the PLA(2)s in induced sputum cells and supernatant was determined by quantitative polymerase chain reaction, immunocytochemistry, and Western blot., Measurements and Main Results: The sPLA(2)s expressed at the highest levels in airway cells of subjects with asthma were groups X and XIIA. Group X sPLA(2) (sPLA(2)-X) was differentially overexpressed in asthma and localized to airway epithelial cells and bronchial macrophages. The gene expression, immunostaining in airway epithelial cells and bronchial macrophages, and the level of the extracellular sPLA(2)-X protein in the airways increased in response to exercise challenge in the asthma group, whereas the levels were lower and unchanged after challenge in nonasthmatic control subjects., Conclusions: Increased expression of sPLA(2)-X may play a key role in the dysregulated eicosanoid synthesis in asthma.

Pulmonary eosinophilia is one of the most consistent hallmarks of asthma. Infiltration of eosinophils into the lung in experimental asthma is dependent on the adhesion molecule vascular cell adhesion molecule-1 (VCAM-1) on endothelial cells. Ligation of VCAM-1 activates endothelial cell NADPH oxidase, which is required for VCAM-1-dependent leukocyte migration in vitro. To examine whether endothelial-derived NADPH oxidase modulates eosinophil recruitment in vivo, mice deficient in NADPH oxidase (CYBB mice) were irradiated and received wild-type hematopoietic cells to generate chimeric CYBB mice. In response to ovalbumin (OVA) challenge, the chimeric CYBB mice had increased numbers of eosinophils bound to the endothelium as well as reduced eosinophilia in the lung tissue and bronchoalveolar lavage. This occurred independent of changes in VCAM-1 expression, cytokine/chemokine levels (IL-5, IL-10, IL-13, IFNgamma, or eotaxin), or numbers of T cells, neutrophils, or mononuclear cells in the lavage fluids or lung tissue of OVA-challenged mice. Importantly, the OVA-challenged chimeric CYBB mice had reduced airway hyperresponsiveness (AHR). The AHR in OVA-challenged chimeric CYBB mice was restored by bypassing the endothelium with intratracheal administration of eosinophils. These data suggest that VCAM-1 induction of NADPH oxidase in the endothelium is necessary for the eosinophil recruitment during allergic inflammation. Moreover, these studies provide a basis for targeting VCAM-1-dependent signaling pathways in asthma therapies.