Effects In Allergic Airway Inflammation Research Articles

German cockroach extract prevents IL-13-induced CCL26 expression in airway epithelial cells through IL-13 degradation.

Inhaled aeroallergens can directly activate airway epithelial cells (AECs). Exposure to cockroach allergens is a strong risk factor for asthma. Cockroach allergens mediate some of their effects through their serine protease activity; protease activity is also a major contributor to allergenicity. The Th2 cytokine interleukin-13 (IL-13) induces upregulation of the eosinophil chemotactic factor CCL26. CCL26 induces eosinophil migration in allergic inflammation. In this work, we studied the effect of cockroach proteases on IL-13-induced effects. Immersed cultures of the human bronchial epithelial cell line BEAS-2B and air-liquid interface (ALI) cultures of primary normal human bronchial epithelial (NHBE) cells were stimulated with IL-13, Blattella Germanica cockroach extract (CE), or both. IL-13-induced genes were analyzed with qRT-PCR. IL-13 induced upregulation of CCL26, periostin, and IL-13Rα2 in bronchial epithelial cells which were decreased by CE. CE was heat-inactivated (HICE) or pre-incubated with protease inhibitors. HICE and CE preincubated with serine protease inhibitors did not prevent IL-13-induced CCL26 upregulation. CE-degraded IL-13 and specific cleavage sites were identified. CE also decreased IL-4-induced CCL26 upregulation and degraded IL-4. Other serine proteases such as bovine trypsin and house dust mite (HDM) serine proteases did not have the same effects on IL-13-induced CCL26. We conclude that CE serine proteases antagonize IL-13-induced effects in AECs, and this CE effect is mediated primarily through proteolytic cleavage of IL-13. IL-13 cleavage by cockroach serine proteases may modulate CCL26-mediated effects in allergic airway inflammation by interfering directly with the pro-inflammatory effects of IL-13 invivo.

Extracellular vesicles of Echinococcus granulosus have therapeutic effects in allergic airway inflammation.

Previous studies have shown that Echinococcus granulosus cystic fluid can alleviate Th2 allergic airway inflammatory responses by increasing the number of CD4+ CD25+ Foxp3+ T (regulatory T; Treg) cells. Parasite-derived extracellular vesicles (EV) are known to not only promote parasite infection by communicating between parasites but also regulate the inflammatory response by acting as an immunomodulatory agent in the host. To evaluate the effect of EV extracted from the cystic fluid of E. granulosus on allergic airway inflammation, gene expression was investigated after administering EV to mouse lung epithelial cells (MLE-12) following 2h of pretreatment with Aspergillus proteins. An allergic airway inflammation animal model was used to investigate the regulation of the inflammatory response by EV and induced with ovalbumin. EV treatment significantly reduced airway resistance and the number of eosinophils and other immune cells in the bronchoalveolar lavage fluid and Th2- and Th17-related cytokine levels. EV pretreatment decreased the number of IL-4+ CD4+ T cells and increased the number of Treg cells in the lung-draining lymph nodes and spleen. Echinococcus granulosus cystic fluid derived EV ameliorated Th2 allergic airway inflammatory through Treg cells, similar to whole cystic fluid treatment. Thus, EV may be important immunomodulatory molecules in cystic fluid.

STAT5 promotes accessibility and is required for BATF-mediated plasticity at the Il9 locus

T helper cell differentiation requires lineage-defining transcription factors and factors that have shared expression among multiple subsets. BATF is required for development of multiple Th subsets but functions in a lineage-specific manner. BATF is required for IL-9 production in Th9 cells but in contrast to its function as a pioneer factor in Th17 cells, BATF is neither sufficient nor required for accessibility at the Il9 locus. Here we show that STAT5 is the earliest factor binding and remodeling the Il9 locus to allow BATF binding in both mouse and human Th9 cultures. The ability of STAT5 to mediate accessibility for BATF is observed in other Th lineages and allows acquisition of the IL-9-secreting phenotype. STAT5 and BATF convert Th17 cells into cells that mediate IL-9-dependent effects in allergic airway inflammation and anti-tumor immunity. Thus, BATF requires the STAT5 signal to mediate plasticity at the Il9 locus.

Effects of allergic airway inflammation and chronic intermittent hypoxia on systemic blood pressure.

Asthma and obstructive sleep apnea (OSA) are highly prevalent chronic conditions, and both are associated with systemic hypertension. Additionally, asthma and OSA reciprocally interact, mutually exacerbating each other. In this study, we tested the effect of allergen-induced lower airway inflammation and concurrent chronic intermittent hypoxia (CIH) on systemic blood pressure (BP), pulmonary function, and proinflammatory cytokines, in a rat model. Brown Norway rats were exposed to 43 days of normoxia (NORM) or CIH, concurrent with weekly house dust mite (HDM) challenges. BP was measured 1 day after the last HDM challenge. On day 44, pulmonary function was tested, and blood for Th-2 and Th-1 cytokine levels was collected. HDM significantly increased mean (P = 0.002), systolic (P = 0.003), and diastolic (P = 0.004) BP compared with saline-challenged controls. Higher mean BP significantly correlated to increased total respiratory system resistance (R2 = 0.266, P = 0.002), driven by an association with parenchymal tissue dampening (R2 = 0.166, P = 0.016). HDM relative to saline-challenged controls increased the expression of serum IL-6 (P = 0.008), but no relationships of systemic BP with IL-6 or any other cytokines were found. CIH did not alter the allergen-induced responses on BP, although it tended to increase the expression of serum IL-6 (P = 0.06) and monocyte chemoattractant protein-1 (MCP-1, P = 0.09), regardless of HDM challenge. Chronic allergen-induced airway inflammation results in systemic hypertension that is correlated to the degree of distal airway obstruction induced by the allergen. These effects do not appear to be explained by the associated systemic inflammation.

Notch ligands DLL4 and Jagged1 exert differential effects in allergic airway inflammation

Abstract Notch is a pleiotropic signaling family that has been implicated in pathogenesis of allergic airway diseases; however, the distinct function of individual Notch ligands remains elusive. By using an OVA-induced murine asthma model, we investigated whether Notch ligands, Jagged1 and DLL4, exert differential effects during allergic airway inflammation. We found that whilst Jagged1 inhibition mitigated Th2-dominated airway inflammation, blockage of DLL4 aggravated the Th2-mediated asthma phenotypes. Additionally, blockage of Jagged1 signaling enhanced IL-17 production and neutrophilic airway infiltration. In vitro, exogenous Jagged1 induced Th2-skewed responses, whereas augmented DLL4 signaling displayed a dual role by promoting expansion of both Tregs and Th17. In vivo, DLL4 blockage impaired Treg differentiation which plausibly resulted in exaggerated asthma phenotypes. On the contrary, administration of DLL4-expressing antigen-presenting cells promoted endogenous Treg expansion and ameliorated the allergic responses. Therefore, whilst Jagged1 induces Th2-skewed inflammation, DLL4 elicits an essential self-regulatory mechanism via Treg-mediated pathway that overcomes Jagged1-induced Th2 responses and facilitates resolution of the airway inflammation. These findings uncover a disparate function of Jagged1 and DLL4 in allergic airway diseases, suggesting the feasibility of Notch ligand-specific targeting in therapy of allergic airway diseases.

Clearance of Aspergillus fumigatus is impaired in the airway in allergic inflammation

BackgroundAspergillus fumigatus (Af) sometimes colonizes and persists within the respiratory tree in some patients with asthma. To date, the precise reasons why the clearance of Af is impaired in patients with asthma remain unknown. ObjectiveTo characterize the effects of allergic airway inflammation on clearance of Af. MethodsControl and Dermatophagoides farinae (Df) allergen-sensitized BALB/c mice were intranasally infected with Af. After 2 and 9 days of infection, the pathology, fungal burden, and cytokine profile in lung tissue were compared. In a different set of experiments, the phagocytotic activity of alveolar macrophages and the expression of their pathogen recognition receptors also were determined. ResultsThe Af conidia and neutrophilic airway inflammation disappeared by day 9 after infection in control mice. In Df-sensitized mice, Af conidia and neutrophilic and eosinophilic airway inflammation persisted at day 9 after infection. Compared with control mice, Df allergen-sensitized mice showed significant increases in interleukin (IL)-5 and decreases in IL-12 and interferon-γ in lung tissues at day 2 after infection. Most importantly, compared with Af-infected non–Df-sensitized mice, IL-17 in lung tissues was significantly decreased in Df allergen-sensitized Af-infected mice at day 2 after infection but was significantly increased at day 9. Alveolar macrophages isolated from Df allergen-sensitized mice exhibited significant decreases in phagocytotic activity and expression of Toll-like receptor-4 and dectin-1 compared with those from control mice. ConclusionIn the airway of patients with allergy, T-helper cell type 2–dominant immunity potentially affects the expression of pathogen recognition receptors and attenuates cellular defense against Af. Prolonged IL-17 production also could play an important role.

Asthma Severity and Expression Of CLC3 On Human Peripheral Blood and Nasal Lavage Eosinophils

RationaleWe have reported the role of CLC3 in TGF-β-induced migration and activation of eosinophils, and increased expression of CLC3b and CLC3e transcript variants on TGF-β and eotaxin-treated eosinophils. Severity of asthma and corticosteroid treatment may determine the CLC3 expression on eosinophils.MethodsEosinophils were isolated from human venous blood (>99%pure; >98%viable) with negative selection from healthy (n=10), mild-to-moderate (n=10) and moderate-to-severe (n=10) allergic asthmatics. Nasal washings were taken from respective groups. Q-PCR, Western blot, and fluorescence microscopy were used to obtain outcome measures.ResultsmRNA transcripts of CLC3 variants varied among groups based on the severity of asthma and corticosteroid treatment. Eosinophils from mild-to-moderate asthmatics had 5-6-fold increase in CLC3 mRNA transcripts compared to healthy volunteers. However, moderate-to-severe asthmatics on inhaled corticosteroid had 2-3-fold increase in CLC3 transcripts. The CLC3b and CLC3e transcripts were increased 5-7 and 6-8-fold in mild-to-moderate asthmatics, and in moderate-severe asthmatics increase by 4-5 and 3-4 fold, respectively. Protein expression of CLC3 also followed the same trend. Asthmatics nasal lavage contained multiple eosinophils expressing different levels of CLC3 with increased expression in mild-to-moderate than moderate-to-severe asthmatic and no inflammatory cells in healthy subjects.ConclusionsThe CLC3 expression on eosinophils correlates with asthma severity. Reduction in CLC3 expression may be an additional mechanism of corticosteroid effects in allergic airway inflammation. Differential CLC3 expression on nasal eosinophils could be a biomarker of asthma severity and treatment with corticosteroids. RationaleWe have reported the role of CLC3 in TGF-β-induced migration and activation of eosinophils, and increased expression of CLC3b and CLC3e transcript variants on TGF-β and eotaxin-treated eosinophils. Severity of asthma and corticosteroid treatment may determine the CLC3 expression on eosinophils. We have reported the role of CLC3 in TGF-β-induced migration and activation of eosinophils, and increased expression of CLC3b and CLC3e transcript variants on TGF-β and eotaxin-treated eosinophils. Severity of asthma and corticosteroid treatment may determine the CLC3 expression on eosinophils. MethodsEosinophils were isolated from human venous blood (>99%pure; >98%viable) with negative selection from healthy (n=10), mild-to-moderate (n=10) and moderate-to-severe (n=10) allergic asthmatics. Nasal washings were taken from respective groups. Q-PCR, Western blot, and fluorescence microscopy were used to obtain outcome measures. Eosinophils were isolated from human venous blood (>99%pure; >98%viable) with negative selection from healthy (n=10), mild-to-moderate (n=10) and moderate-to-severe (n=10) allergic asthmatics. Nasal washings were taken from respective groups. Q-PCR, Western blot, and fluorescence microscopy were used to obtain outcome measures. ResultsmRNA transcripts of CLC3 variants varied among groups based on the severity of asthma and corticosteroid treatment. Eosinophils from mild-to-moderate asthmatics had 5-6-fold increase in CLC3 mRNA transcripts compared to healthy volunteers. However, moderate-to-severe asthmatics on inhaled corticosteroid had 2-3-fold increase in CLC3 transcripts. The CLC3b and CLC3e transcripts were increased 5-7 and 6-8-fold in mild-to-moderate asthmatics, and in moderate-severe asthmatics increase by 4-5 and 3-4 fold, respectively. Protein expression of CLC3 also followed the same trend. Asthmatics nasal lavage contained multiple eosinophils expressing different levels of CLC3 with increased expression in mild-to-moderate than moderate-to-severe asthmatic and no inflammatory cells in healthy subjects. mRNA transcripts of CLC3 variants varied among groups based on the severity of asthma and corticosteroid treatment. Eosinophils from mild-to-moderate asthmatics had 5-6-fold increase in CLC3 mRNA transcripts compared to healthy volunteers. However, moderate-to-severe asthmatics on inhaled corticosteroid had 2-3-fold increase in CLC3 transcripts. The CLC3b and CLC3e transcripts were increased 5-7 and 6-8-fold in mild-to-moderate asthmatics, and in moderate-severe asthmatics increase by 4-5 and 3-4 fold, respectively. Protein expression of CLC3 also followed the same trend. Asthmatics nasal lavage contained multiple eosinophils expressing different levels of CLC3 with increased expression in mild-to-moderate than moderate-to-severe asthmatic and no inflammatory cells in healthy subjects. ConclusionsThe CLC3 expression on eosinophils correlates with asthma severity. Reduction in CLC3 expression may be an additional mechanism of corticosteroid effects in allergic airway inflammation. Differential CLC3 expression on nasal eosinophils could be a biomarker of asthma severity and treatment with corticosteroids. The CLC3 expression on eosinophils correlates with asthma severity. Reduction in CLC3 expression may be an additional mechanism of corticosteroid effects in allergic airway inflammation. Differential CLC3 expression on nasal eosinophils could be a biomarker of asthma severity and treatment with corticosteroids.

Viral Disruption of Olfactory Progenitors Is Exacerbated in Allergic Mice

Objectives: Viral infection in the upper respiratory tract (URT) is a major cause of olfactory impairment. Allergic inflammation such as asthma or rhinosinusitis often exacerbates smell problems in patients with viral infections by a mechanism that remains unclear. Here, we examined the effects of allergic airway inflammation on the progression of virus infection and on olfactory lineage cell populations in a mouse model of respiratory syncytial virus (RSV) infection. Methods: Balb/c mice were immunized subcutaneously and intraperitoneally with cockroach antigen (CR) on day −22, then administrated intranasally with CR every 4 days from day −8 to day 0 to induce asthma and allergic inflammation (allergic mice). Allergic and control mice were infected intranasally with RSV line 19 on day 0. RSV-RNA in the nasal mucosa and olfactory bulb were quantified by reverse transcription polymerase chain reaction (RT-PCR). The numbers of OMP+ mature olfactory neurons (ORNs), Sox2+ olfactory progenitor cells (OPs), and CK5+ basal cells (BCs) were determined by immunohistochemical staining. Results: RSV-RNA rapidly decreased and became undetectable on day 14 in control mice, whereas RSV-RNA persisted over 14 days in allergic mice. There were no changes in OMP+ORN or CK5+BC numbers following RSV infection. In control mice, Sox2+OP numbers were significantly reduced on day 2 but recovered thereafter. In allergic mice, this decrease was more severe and prolonged. Conclusions: Allergic background impedes RSV clearance in the URT and exacerbates viral disruption of Sox2+OPs. These results provide novel insight into the mechanism underlying the exacerbation of virus-induced olfactory impairment in allergic airway inflammation.

Pituitary adenylate cyclase‐activating peptide receptor 1 mediates anti‐inflammatory effects in allergic airway inflammation in mice

Bronchial asthma is characterized by airway inflammation and reversible obstruction. Since the gold standard of therapy, a combination of anti-inflammatory corticosteroids and bronchodilatory β(2) agonists, has recently been discussed to be related to an increased mortality, there is a need for novel therapeutic pathways. A new experimental concept that encompasses the vasoactive intestinal peptide/pituitary adenylate cyclase activating peptide (PACAP) family of receptors by demonstrating the anti-inflammatory effects of the PACAP receptor 1 (PAC1R) in a murine model of allergic asthma is described. PAC1R expression was investigated in lung tissue and isolated dendritic cells (DCs) via real-time PCR. Ovalbumin (OVA)-induced asthma models were used in PAC1R-deficient mice and BALB/c mice treated with PAC1R agonist maxadilan (MAX). Bronchoalveolar lavages have been performed and investigated at the cellular and cytokine levels. Fluorescence staining of a frozen lung section has been performed to detect eosinophil granulocytes in lung tissue. Plasma IgE levels have been quantified via the ELISA technique. Lung function was determined using head-out body plethysmography or whole-body plethysmography. Increased PAC1R mRNA expression in lung tissue was present under inflammatory conditions. PAC1R expression was detected on DCs. In OVA-induced asthma models, which were applied to PAC1R-deficient mice (PAC1R(-/-)) and to BALB/c mice treated with the specific PAC1R agonist MAX, PAC1R deficiency resulted in inflammatory effects, while agonistic stimulation resulted in anti-inflammatory effects. No effects on lung function were detected both in the gene-depletion and in the pharmacologic studies. In summary, here, we demonstrate that anti-inflammatory effects can be achieved via PAC1R. PAC1R agonists may represent a promising target for an anti-inflammatory therapy in airway diseases such as bronchial asthma.

Intravascular inactivation of CCR5 byn-Nonanoyl-CC chemokine ligand 14 and inhibition of allergic airway inflammation

Modulation of leukocyte recruitment through intervention with chemokine receptors is an attractive, therapeutic strategy. Recently, we have shown that n-Nonanoyl (NNY)-CCL14 internalizes and desensitizes human (h)CCR3, resulting in the inactivation of eosinophils. In this study, we investigated the interaction of NNY-CCL14 with CCR1 and CCR5 and the relevance of these NNY-CCL14 receptors on its in vivo effects in allergic airway inflammation. NNY-CCL14 has inactivating properties on CCR1(+) and CCR5(+) cell lines and primary leukocytes. It desensitizes hCCR1- and hCCR5-mediated calcium release and internalizes these receptors from the cellular surface. Treatment of OVA-sensitized BALB/c mice with NNY-CCL14 resulted in reduced pulmonary inflammation. Above all, it is demonstrated that systemic treatment with NNY-CCL14 down-modulates CCR5 from the surface of lymphocytes in vivo. Although NNY-CCL14 acts on murine lymphocytes and internalizes CCR5, it does not internalize CCR3 on mouse eosinophils, showing species selectivity regarding this particular receptor. Therefore, the inhibitory effects of NNY-CCL14 in murine models of allergic airway inflammation can be assigned to its interaction with CCR5. The presented results substantiate the relevance of CCR5 as a target for allergic airway inflammation.

Acute and chronic effects of allergic airway inflammation on pulmonary nitric oxide production.

Nitric oxide (NO) is thought to be an important modulator of airway function in normal and inflamed airways. We investigated the acute and chronic effects of induced allergic airway inflammation on NO levels in mixed expired gas and NO synthase (NOS) expression in guinea pigs and the relationship between airway responses and NO production. Airway inflammation was induced by repeated aerosolized antigen exposure, and its presence was confirmed by bronchoalveolar lavage. Acute antigen exposure in sensitized animals produced a fivefold increase in respiratory resistance over baseline that was associated with a cotemporal increase in expired NO (17 +/- 1 to 56 +/- 8 parts per billion, P < 0.01). A continuous subcutaneous infusion of nitro-L-arginine methyl ester (L-NAME), a competitive inhibitor of NOS, markedly decreased expired NO (P < 0.01) and resulted in a significantly greater rise in resistance following antigen challenge (660 +/- 60 vs. 497 +/- 42% of baseline in non-L-NAME-treated animals, P < 0.05). These data support the hypothesis that endogenous pulmonary NO production, as reflected by expired NO, has an important homeostatic role in acute allergic bronchoconstriction.