Airway Eosinophil Infiltration Research Articles

Resveratrol modulates the Nrf2/NF-κB pathway and inhibits TSLP-mediated atopic march.

Resveratrol has been found to have anti-inflammatory and anti-allergic properties. The effects of resveratrol on thymic stromal lymphopoietin (TSLP)-mediated atopic march remain unclear. To explore the potential role of resveratrol in TSLP-mediated atopic march. The atopic march mouse model was established by topical application of MC903 (a vitamin D3 analog). Following the treatment with resveratrol, airway resistance in mice was discovered by pulmonary function apparatus, and the number of total cells, neutrophils, and eosinophils in bronchoalveolar lavage fluid was counted. The histopathological features of pulmonary and ear skin tissues, inflammation, and cell infiltration were determined by hematoxylin and eosin staining. The messenger RNA (mRNA) levels of TSLP, immunoglobulin E, interleukin (IL)-4, IL-5, and IL-13 were measured by real-time quantitative polymerase chain reaction. The protein expression of nuclear factor kappa B (NF-κB)/nuclear factor erythroid 2-related factor 2 (Nrf2) signaling-associated molecules (p-p65, p65, p-I kappa B kinase alpha (IκBα), IκBα, Nrf2, and TSLP) in lung and ear skin tissues were assessed by Western blot analysis. Resveratrol attenuated airway resistance and infiltration of total cells, eosinophils, and neutrophils in both lung and ear skin tissues. Resveratrol ameliorates serum inflammatory markers in allergic mice. Moreover, the phosphorylation levels of NF-κB pathway-related proteins were significantly reduced by administration of resveratrol in allergic lung and ear skin tissues. Similarly, the protein expression of TSLP in both lung and ear skin tissues was reduced by resveratrol, and Nrf2, a protector molecule, was increased with resveratrol treatment. Resveratrol attenuates TSLP-reduced atopic march through ameliorating inflammation and cell infiltration in pulmonary and ear skin tissues by inhibiting the abnormal activation of NF-κB signaling pathway.

Mulberroside F improves airway hyperresponsiveness and inflammation in asthmatic mice.

Mulberroside F is isolated from the leaves and roots of Morus alba L. Here, we investigated whether mulberroside F could alleviate airway inflammation and eosinophil infiltration in the lungs of asthmatic mice. We also examined whether mulberroside F attenuated inflammatory responses in human tracheal epithelial BEAS-2B cells. Female BALB/c mice were sensitized and challenged with ovalbumin (OVA), and administered different doses of mulberroside F via intraperitoneal injection. Additionally, tumor necrosis factor (TNF)-α-stimulated BEAS-2B cells were treated with various doses of mulberroside F, followed by detection of the expressions of inflammatory cytokines and chemokines. The results demonstrated that mulberroside F mitigated the levels of proinflammatory cytokines and chemokines, and CCL11, in inflammatory BEAS-2B cells. Mulberroside F also suppressed reactive oxygen species (ROS) production and ICAM-1 expression in TNF-α-stimulated BEAS-2B cells, which effectively suppressed monocyte cell adherence. In an animal model of asthma, mulberroside F treatment attenuated airway hyperresponsiveness, eosinophil infiltration, and goblet cell hyperplasia. Mulberroside F treatment also decreased lung fibrosis and airway inflammation in OVA-sensitized mice. Moreover, mulberroside F significantly reduced expressions of Th2-associated cytokines (including interleukin(IL)-4, IL-5, and IL-13) in bronchoalveolar lavage fluid compared to OVA-sensitized mice. Our results confirmed that mulberroside F is a novel bioactive compound that can effectively reduce airway inflammation and eosinophil infiltration in asthmatic mice via inhibition of Th2-cell activation.

Phillyrin attenuates airway inflammation and Th2 cell activities in a mouse asthma model

ABSTRACT Phillyrin is isolated from the fruit of Forsythia suspensa, and exhibits multiple pharmacological effects, including anti-tumor, anti-inflammation, and anti-oxidation activities. Here, we investigated whether phillyrin could alleviate airway hyperresponsiveness (AHR) and eosinophil infiltration in the lungs of asthmatic mice, and mitigate inflammatory responses in tracheal epithelial BEAS-2B cells. IL-4/TNF-α-stimulated BEAS-2B cells were treated with various phillyrin doses. Female BALB/c mice were sensitised and challenged with ovalbumin (OVA), and then treated with intraperitoneal injection different phillyrin doses. In IL-4/TNF-α-stimulated BEAS-2B cells, phillyrin effectively reduced proinflammatory cytokines, chemokines, and eotaxin (CCL11) levels. In the lungs of asthmatic mice, phillyrin treatment relieved AHR, airway inflammation, eosinophil infiltration, and goblet cell hyperplasia. Phillyrin also reduced serum OVA-IgE, and Th2-associated cytokine levels in splenocyte culture medium, and in bronchoalveolar lavage fluid of asthmatic mice. Our results indicate that phillyrin attenuated airway inflammation and eosinophil infiltration in asthmatic mice by suppressing Th2 cytokine production.

IL-1β Derived Th17 Immune Responses Are a Critical Factor for Neutrophilic-Eosinophilic Airway Inflammation on Psychological Stress-Induced Immune Tolerance Breakdown in Mice

Introduction: Asthma is an inflammatory reaction mediated by type 2 helper T (Th2) cells and is known to increase eosinophil levels. Our previous study showed that stress-related asthma can cause neutrophilic and eosinophilic airway inflammation by suppressing immune tolerance. However, the mechanism of stress-induced neutrophilic and eosinophilic airway inflammation remains unclear. Therefore, to elucidate the cause of neutrophilic and eosinophilic inflammation, we investigated the immune response during the induction of airway inflammation. In addition, we focused on the relationship between immune response modulation immediately after stress exposure and the development of airway inflammation. Methods: Asthmatic mice were induced by three phases using female BALB/c mice. During the first phase, the mice were made to inhale ovalbumin (OVA) to induce immune tolerance before sensitization. Some mice were exposed to restraint stress during the induction of immune tolerance. In the second phase, the mice were sensitized with OVA/alum intraperitoneal injections. In the final phase, onset of asthma was induced through OVA exposure. Asthma development was evaluated based on airway inflammation and T-cell differentiation. Microarray and qPCR analyses were used to enumerate candidate factors to investigate the starting point of immunological modification immediately after stress exposure. Furthermore, we focused on interleukin-1β (IL-1β), which initiates these immune modifications, and performed experiments using its receptor blocker interleukin-1 receptor antagonist (IL-1RA). Results: Stress exposure during immune tolerance induction increased eosinophil and neutrophil airway infiltration. This inflammation was associated with decreased T regulatory cell levels and increased Th2 and Th17 levels in bronchial lymph node cells. Microarray and qPCR analyses showed that the initiation of Th17 differentiation might be triggered by stress exposure during tolerance induction. IL-1RA administration during stress exposure suppressed neutrophilic and eosinophilic airway inflammation via Th17 reduction and Treg increase. Conclusions: Our results show that psychological stress causes both eosinophilic and neutrophilic inflammatory responses due to the breakdown of immune tolerance. Furthermore, stress-induced inflammation can be abolished using IL-1RA.

MIF is essential to the establishment of house dust mite-induced airway inflammation and tissue remodeling in mice.

Macrophage migration inhibitory factor (MIF) is present in high amounts in the bronchoalveolar lavage fluid (BALF) and serum of asthmatic patients contributing to the pathogenesis of experimental asthma induced by ovalbumin (OVA) in mice. Whether MIF contributes to the physiopathology on a more complex and relevant asthma model has not been characterized. Mif-deficient (Mif-/- ) or wild-type (WT) mice treated with anti-MIF antibody were challenged multiple times using house dust mite (HDM) extract by intranasal route. HDM-challenged Mif-/- mice presented decreased airway hyperresponsiveness, lung infiltration of eosinophils, mucus hypersecretion and subepithelial fibrosis compared to HDM-challenged WT mice. Amounts IL-4, IL-5 and IL-13 were decreased in the lungs of Mif-/- mice upon HDM challenges, but the increase of CCL11 was preserved, compared to HDM-challenged WT mice. We also observed increased numbers of group 2 innate lymphoid cells and Th2 cells in the BALF and mediastinal lymph nodes (mLN) induced challenged by HDM of WT mice, but not in HDM-challenged Mif-/- mice. Anti-MIF treatment abrogated the airways infiltration of eosinophils, mucus hypersecretion and subepithelial fibrosis in the lungs of HDM-challenged mice. In conclusion, MIF ablation prevents the pathologic hallmarks of asthma in HDM-challenged mice, reinforcing the promising target of MIF for asthma therapy. This article is protected by copyright. All rights reserved.

MARCH1 Controls an Exhaustion-like Program of Effector CD4+ T Cells Promoting Allergic Airway Inflammation.

Persistent antigenic signaling leads to T cell exhaustion, a dysfunctional state arising in many chronic infections and cancers. Little is known concerning mechanisms limiting exhaustion in immune-stimulatory diseases such as asthma. We report that membrane-associated RING-CH1 (MARCH1), the ubiquitin ligase that mediates surface turnover of MHC class II (MHCII) and CD86 in professional APCs, plays an essential role in restraining an exhaustion-like program of effector CD4+ T cells in a mouse model of asthma. Mice lacking MARCH1 or the ubiquitin acceptor sites of MHCII and CD86 exhibited increased MHCII and CD86 surface expression on lung APCs, and this increase promoted enhanced expression of immune-inhibitory receptors by effector CD4+ T cells and inhibited their proliferation. Remarkably, ablation of MARCH1 in mice with established asthma reduced airway infiltration of eosinophils and Th2 cells. Thus, MARCH1 controls an exhaustion-like program of effector CD4+ T cells during allergic airway inflammation and may serve as a therapeutic target for asthma.

DJ-1 governs airway progenitor cell/eosinophil interactions to promote allergic inflammation

DJ-1 is an antioxidant protein known to regulate mast cell-mediated allergic response, but its role in airway eosinophilic interactions and allergic inflammation is not known. The aim of this study was to investigate the role of DJ-1 in airway eosinophilic inflammation invitro and invivo. Ovalbumin-induced airway allergic inflammation was established in mice. ELISA was adopted to analyze DJ-1 and cytokine levels in mouse bronchoalveolar lavage fluid. Transcriptional profiling of mouse lung tissues was conducted by single-cell RNA-sequencing technology. The role of DJ-1 in the differentiation of airway progenitor cells into goblet cells was examined by organoid cultures, immunofluorescence staining, quantitative PCR, and cell transplantation in normal, DJ-1 knockout (KO), or conditional DJ-1 KO mice. This study observed that DJ-1 was increased in the lung tissues of ovalbumin-sensitized and challenged mice. DJ-1 KO mice exhibited reduced airway eosinophil infiltration and goblet cell differentiation. Mechanistically, we discovered that eosinophil-club cell interactions are reduced in the absence of DJ-1. Organoid cultures indicated that eosinophils impair the proliferative potential of club cells. Intratracheal transplantation of DJ-1-deficient eosinophils suppresses airway goblet cell differentiation. Loss of DJ-1 inhibits the metabolism of arachidonic acid into cysteinyl leukotrienes in eosinophils while these secreted metabolites promote airway goblet cell fate in organoid cultures and invivo. DJ-1-mediated interactions between airway epithelial progenitor cells and immune cells are essential in controlling airway goblet cell metaplasia and eosinophilia. Blockade of the DJ-1 pathway is protective against airway allergic inflammation.

The STAT6 inhibitor AS1517499 reduces the risk of asthma in mice with 2,4-dinitrochlorobenzene-induced atopic dermatitis by blocking the STAT6 signaling pathway

BackgroundEpidemiological studies have revealed a link between atopic dermatitis (AD) and asthma. AS1517499, a selective signal transducer and activation of transcription 6 (STAT6) inhibitor, has been shown to effectively block this connection. In this study, we further explored the underlying mechanism by constructing an AD mouse model.MethodsFemale BALB/c mice were randomly divided into four groups (n = 10/group). The AD mouse model was established by 2,4-dinitrochlorobenzene induction with repeated ovalbumin challenge. AS1517499 and corn oil were used as treatment interventions. The features of airway inflammation, remodeling, and hyperactivity were analyzed.ResultsActive use of AS1517499 in AD mice effectively reduced Th2-related cytokine levels, alleviated airway eosinophil and lymphocyte infiltration, and regulated GATA3/Foxp3 levels and subepithelial collagen deposition. These changes might be due to specific blockade of the STAT6 signaling pathway.ConclusionAS1517499 could partially block the association between AD and asthma by specifically inhibiting the STAT6 signaling pathway.

Critical roles of interleukin-33/suppression of tumorigenicity 2 (IL-33/ST2) in pulmonary disorders.

Critical roles of interleukin-33/suppression of tumorigenicity 2 (IL-33/ST2) in pulmonary disorders.

Early IL-17A Prevention Rather Than Late IL-17A Neutralization Attenuates Toluene Diisocyanate-Induced Mixed Granulocytic Asthma.

PurposeInterleukin (IL)-17A plays a critical role in the pathogenesis of allergic airway inflammation. Yet, the exact roles of IL-17A in asthma are still controversial. Thus, the aim of this study was to dissect the roles of IL-17A in toluene diisocyanate (TDI)-induced mixed granulocytic asthma and to assess the effects of neutralizing antibody in different effector phases on TDI-induced asthma.MethodsIL-17A functions in allergic airway inflammation were evaluated using mice deficient in IL-17A (Il17a−/−) or IL-17A monoclonal antibody (IL-17A mab, intraperitoneally, 50 μg per mouse, 100 μg per mouse). Moreover, the effects of exogenous recombinant IL (rIL)-17A in vivo (murine rIL-17A, intranasally, 1 μg per mouse) and in vitro (human rIL-17A, 100 ng/mL) were investigated.ResultsTDI-induced mixed granulocytic airway inflammation was IL-17A-dependent because airway hyperreactivity, neutrophil and eosinophil infiltration, airway smooth muscle thickness, epithelium injury, dysfunctional T helper (Th) 2 and Th17 responses, granulocytic chemokine production and mucus overproduction were more markedly reduced in the Il17a−/− mice or by IL-17A neutralization during the sensitization phase of wild-type (WT) mice. By contrast, IL-17A neutralization during the antigen-challenge phase aggravated TDI-induced eosinophils recruitment, with markedly elevated Th2 response. In line with this, instillation of rIL-17 during antigen sensitization exacerbated airway inflammation by promoting neutrophils aggregation, while rIL-17A during the antigen-challenge phase protected the mice from TDI-induced airway eosinophilia. Moreover, rIL-17A exerted distinct effects on eosinophil- or neutrophil-related signatures in vitro.ConclusionsOur data demonstrated that IL-17A was required for the initiation of TDI-induced asthma, but functioned as a negative regulator of established allergic inflammation, suggesting that early abrogation of IL-17A signaling, but not late IL-17A neutralization, may prevent the progression of TDI-induced asthma and could be used as a therapeutic strategy for severe asthmatics in clinical settings.

Sputum IL-25, IL-33 and TSLP, IL-23 and IL-36 in airway obstructive diseases. Reduced levels of IL-36 in eosinophilic phenotype

IntroductionAlarmins ((IL-25, IL-33 and thymic stromal lymphopoietin (TSLP)) are known to promote Th2 inflammation and could be associated with eosinophilic airway infiltration. They may also play a role in airway remodeling in chronic airway obstructive diseases such as asthma and chronic obstructive pulmonary disease (COPD). IL-23 and IL-36 were shown to mediate the neutrophilic airway inflammation as seen in chronic airway obstructive diseases. Objectives: The purpose of this project was to determine the expression and the production of these cytokines from induced sputum (IS) in patients with chronic airway obstructive diseases including asthmatics and COPD. The relationship of the mediators with sputum inflammatory cellular profile and the severity of airway obstruction was assessed. MethodsThe alarmins (IL-25, IL-33 and TSLP) as well as IL-23 and IL-36 concentrations were measured in IS from 24 asthmatics and 20 COPD patients compared to 25 healthy volunteers. The cytokines were assessed by ELISA in the IS supernatant and by RT-qPCR in the IS cells. ResultsAt protein level, no difference was observed between controls and patients suffering from airway obstructive diseases regarding the different mediators. IL-36 protein level was negatively correlated with sputum eosinophil and appeared significantly decreased in patients with an eosinophilic airway inflammation compared to those with a neutrophilic profile and controls. At gene level, only IL-36, IL-23 and TSLP were measurable but none differed between controls and patients with airway obstructive diseases. IL-36 and IL-23 were significantly increased in patients with an neutrophilic inflammatory profile compared to those with an eosinophilic inflammation and were correlated with sputum neutrophil proportions. None of the mediators were linked to airway obstruction. ConclusionsThe main finding of our study is that patients with eosinophilic airway inflammation exhibited a reduced IL-36 level which could make them more susceptible to airway infections as IL-36 is implicated in antimicrobial defense. This study showed also an implication of IL-36 and IL-23 in airway neutrophilic inflammation in chronic airway obstructive diseases.

Helminthostachys zeylanica Water Extract Ameliorates Airway Hyperresponsiveness and Eosinophil Infiltration by Reducing Oxidative Stress and Th2 Cytokine Production in a Mouse Asthma Model.

Helminthostachys zeylanica is a traditional folk herb used to improve inflammation and fever in Taiwan. Previous studies showed that H. zeylanica extract could ameliorate lipopolysaccharide-induced acute lung injury in mice. The aim of this study was to investigate whether H. zeylanica water (HZW) and ethyl acetate (HZE) extracts suppressed eosinophil infiltration and airway hyperresponsiveness (AHR) in asthmatic mice, and decreased the inflammatory response and oxidative stress in tracheal epithelial cells. Human tracheal epithelial cells (BEAS-2B cells) were pretreated with various doses of HZW or HZE (1 μg/ml–10 μg/ml), and cell inflammatory responses were induced with IL-4/TNF-α. In addition, female BALB/c mice sensitized with ovalbumin (OVA), to induce asthma, were orally administered with HZW or HZE. The result demonstrated that HZW significantly inhibited the levels of proinflammatory cytokines, chemokines, and reactive oxygen species in activated BEAS-2B cells. HZW also decreased ICAM-1 expression and blocked monocytic cells from adhering to inflammatory BEAS-2B cells in vitro. Surprisingly, HZW was more effective than HZE in suppressing the inflammatory response in BEAS-2B cells. Our results demonstrated that HZW significantly decreased AHR and eosinophil infiltration, and reduced goblet cell hyperplasia in the lungs of asthmatic mice. HZW also inhibited oxidative stress and reduced the levels of Th2 cytokines in bronchoalveolar lavage fluid. Our findings suggest that HZW attenuated the pathological changes and inflammatory response of asthma by suppressing Th2 cytokine production in OVA-sensitized asthmatic mice.

Épidémiologie et physiopathologie de l’inflammation de type 2 dans l’asthme sévère: Epidemiology and pathophysiology of type 2 inflammation in severe asthma

Type 2 (T2) inflammation is defined by the production of the cytokines IL-4, IL-5 and IL-13 and is characterized by an allergic and/or eosinophilic reaction. It includes the Th2 response (adaptive reaction with specific antigenic recognition) and the one linked to type 2 innate lymphoid cells (ILC2) (innate reaction without specific antigenic recognition). Epidemiological data on T2 severe asthma are heterogeneous depending on the cohorts characteristics and the definition of T2 inflammation. About 2/3 of severe asthmatics could have an allergic phenotype and 2/3 a eosinophilic phenotype with an overlap between these two populations not evaluated. In asthma, T2 inflammation arises from the interaction between genetic susceptibility (genetic polymorphisms and/or epigenetic changes) and environmental factors (allergens, viruses, pollutants). T2 inflammation involves an allergic reaction to aeroallergens (Th2 response) and/or an innate response to environmental agents (“ILC2 response”). The allergic reaction is characterized by the production of aeroallergen-specific IgE (sensitization), leading to mast cell degranulation upon exposure to aero-allergens and a delayed reaction with airway eosinophilic infiltration. The innate reaction consists of the activation of ILC2 mediated by alarmins, which are produced by the bronchial epithelium in response to environmental agents, leading to the recruitment of eosinophils into airways. T2 inflammation is classically steroid sensitive but in severe asthma, there is a steroid resistance that may be due to pathways involved in steroids mechanisms of action.© 2020 SPLF. Published by Elsevier Masson SAS. All rights reserved.

Establishment of a mouse model with all four clinical features of eosinophilic bronchitis

Eosinophilic bronchitis (EB) is a clinical disease characterized by chronic cough, airway eosinophil infiltration, and responsive to steroid therapy but with the absence of airway hyperreactivity (AHR). This study established an EB mouse model with all the above features. First, 42 mice were divided into 7 groups to investigate the optimal time interval between cough and AHR detections. Afterward, 28 mice were divided into the asthma, EB, normal saline (NS), and dexamethasone (DXM) groups. Mice were challenged using nasal drops of 200 µg ovalbumin (OVA), 10 µg OVA, NS, or intraperitoneal injections of 5 mg/kg of DXM one hour prior to 10 µg OVA challenge. Airway reactivity was measured 6 h after cough was observed. The frequency of coughs in the asthma and EB groups increased significantly compared to mice in the NS group. After DXM administration, frequency of coughs was significantly decreased compared to mice in the asthma and EB groups. Lung resistance in the asthma group was significantly higher compared to mice in the NS, EB, and DXM groups. Obvious airway eosinophilic inflammation in BALF and lung tissues were observed in the asthma and EB groups, while DXM administration could attenuate airway inflammatory infiltration. In summary, we developed a mouse EB model with all four clinical features of EB by the administration of 10 µg OVA nasal drops.

Oral administration of Sargassum horneri extract containing Mojabanchromanol attenuates PM-exacerbated allergic airway response in murine model of asthma

Abstract Epidemiological studies indicate correlation with particulate matter (PM) and the pathogenesis of airway inflammatory lung diseases. We sought to identify whether Sargassum horneri ethanol extract containing mojabanchromanol (SHE) confers maximal health benefit against PM exacerbated allergic asthma. Using BALB/c mice undergoing sensitization and challenge with ovalbumin (OVA, 10 μg) we developed a PM exacerbated mouse model of asthma. After 2 weeks of sensitization, mice were challenged with PM (5 mg/m3) for 7 days consecutively together with oral administration of SHE (200, 400 mg/Kg), Prednisone (5mg/Kg) or PBS. SHE restrained Th2 polarization by attenuating transcription factors GATA3 and Signal transducer and activator of transcription (STAT) 5. This resulted in mitigated eosinophil infiltration in airway and balf and secretion of Th2 cytokines interleukin (IL)-4, IL-5, IL-13 in lung homogenates of PM exacerbated asthmatic mice. Immunoglobulin (Ig) E secretion in serum and activation of mast cells in trachea were markedly attenuated. Concomitantly, SHE further restrained the Th17 cell response in PM exposed allergic mice through attenuating expression of transcription factors RORγT, STAT3 and expression of relevant effector cytokines IL-17a. This further mitigated CD11b+ Ly6G+ neutrophil population in lung. Taken together, SHE significantly suppressed PM exacerbated histopathological changes, hyper secretion of mucus in asthmatic mice. These results suggest that SHE might portend a natural candidate against against PM exacerbated allergic asthma via concomitant inhibiting of Th2/Th17 responses. This research was supported by the Ministry of Oceans and Fisheries, Korea (No. 20170285).

Therapeutic approach to steroid-resistant asthma

Abstract Background To control therapy-resistant eosinophilia, synergistic effects of CTLA4-Ig and glucocorticoid was investigated on T cell-induced asthma model. Methods Ovalbumin (OVA) specific murine helper T cell (Th) clones were established from DO11.10 transgenic mice. To analyze steroid responsiveness in vitro, Th clones were cultured with antigen presenting cells and OVA in the presence of various concentration of dexamethasone (DEX). Proliferative responses were measured by incorporation of either 3H-thymidine or BrdU. For in vivo analysis, unprimed Balb/c mice were transferred with Th clones, challenged with OVA, and administered with DEX subcutaneously. CTLA4-Ig was administered intravenously. BALF was obtained 48 hours after the challenge, and the number of infiltrating cells was differentially counted. Results Steroid-sensitive (SS) and -resistant (SR) clones were selected based on the effect of DEX on the proliferative responses of antigen-stimulated Th clones. Airway infiltration of eosinophils of mice transferred with SS clones were effectively inhibited by the administration of DEX. In contrast, those of mice transferred with SR clones were not significantly inhibited by DEX. Addition of CTLA4-Ig into the culture significantly suppressed the proliferation of DEX-treated SR clones in vitro. Administration of CTLA4-Ig significantly suppressed eosinophil infiltration of SR asthma model transferred with SR clones in vivo. CTLA4-Ig and DEX synergistically suppressed in vitro proliferation of SS clones and in vivo BALF eosinophilia of mice transferred with SS clones. Conclusion Blocking costimulatory signal mediated through CD28 is a promising target to treat therapy-resistant eosinophilia.

Plasma based targeted metabolomic analysis reveals alterations of phosphatidylcholines and oxidative stress markers in guinea pig model of allergic asthma

Bronchial asthma is one of the most common, chronic respiratory diseases, characterized by reversible airway obstruction, eosinophil and Th2 infiltration, airway hyperresponsiveness and airway remodelling; with many cells and mediators involved. Metabolomics is a relatively new field in “omics” sciences enabling the identification of metabolome for better diagnostics and studying of diseases phenotype.The aim of this study was to investigate the role of targeted metabolomics study for better understanding of the bronchial asthma pathophysiology and finding potential biomarkers in experimental models of eosinophilic inflammation.Plasma level of 185 metabolites was measured with the AbsoluteIDQ™ p180 kit in guinea pigs with experimentally-induced allergic inflammation (n = 15) compared to naïve non-sensitised and non-challenged controls (n = 18).Of the 185 metabolites identified in plasma, 22 were significantly different and changed in ovalbumin sensitised animals. Plasma level of 13 phosphatidylcholines with saturated and unsaturated long-chain fatty acids, total phosphatidylcholines count, carnitine, symmetric dimethylarginine and its ratio to total unmodified arginine, and kynurenine to tryptophan ratio were found to be decreased, while phospholipase A2 activity indicator, tryptophan, taurine and ratio of methionine sulfoxide to unmodified methionine were found to be increased in sensitised guinea pigs compared to naïve controls.Targeted metabolomic analysis revealed significant differences in plasma metabolome of sensitised guinea pigs. Our observations point to the activation of inflammatory and immune pathways, as well as the involvement of oxidative stress.

Protective Effects of Licochalcone A Improve Airway Hyper-Responsiveness and Oxidative Stress in a Mouse Model of Asthma.

Licochalcone A was isolated from Glycyrrhiza uralensis and previously reported to have antitumor and anti-inflammatory effects. Licochalcone A has also been found to inhibit the levels of Th2-associated cytokines in the bronchoalveolar lavage fluid (BALF) of asthmatic mice. However, the molecular mechanism underlying airway inflammation and how licochalcone A regulates oxidative stress in asthmatic mice are elusive. In this study, we investigated whether licochalcone A could attenuate inflammatory and oxidative responses in tracheal epithelial cells, and whether it could ameliorate oxidative stress and airway inflammation in asthmatic mice. Inflammatory human tracheal epithelial (BEAS-2B) cells were treated with licochalcone A to evaluate oxidative responses and inflammatory cytokine levels. In addition, BALB/c mice were sensitized with ovalbumin (OVA) and injected intraperitoneally with licochalcone A (5 or 10 mg/kg). Licochalcone A significantly inhibited reactive oxygen species, eotaxin, and proinflammatory cytokines in BEAS-2B cells. Licochalcone A also decreased intercellular adhesion molecule 1 levels in inflammatory BEAS-2B cells, blocking monocyte cell adherence. We also found that licochalcone A significantly decreased oxidative responses, reduced malondialdehyde levels, and increased glutathione levels in the lungs of OVA-sensitized mice. Furthermore, licochalcone A decreased airway hyper-responsiveness, eosinophil infiltration, and Th2 cytokine production in the BALF. These findings suggest that licochalcone A alleviates oxidative stress, inflammation, and pathological changes by inhibiting Th2-associated cytokines in asthmatic mice and human tracheal epithelial cells. Thus, licochalcone A demonstrated therapeutic potential for improving asthma.

APD588, a novel, selective S1P- receptor modulator, inhibits inflammation and airway hyperresponsiveness in the ovalbumin-induced model of allergic asthma

Abstract Background FTY720 is a non-selective sphingosine-1-phosphate (S1P) receptor modulator that has shown efficacy in mouse asthma models. APD588 is an investigational stage S1P receptor modulator with increased selectivity and potential for an improved safety profile. We hypothesized that the optimized S1P receptor profile of APD588 would confer beneficial effects in ovalbumin (OVA)-induced asthma. Aim To evaluate efficacy of prophylactic APD588 in the OVA-induced allergic asthma model Methods Receptor potency and selectivity profile of APD588 was determined (b-arrestin, GTPgS) in cell lines expressing recombinant human S1P1–5. Efficacy in allergic asthma was assessed in BALB/c mice which were sensitized with intraperitoneal OVA on days 0, 7, and 17, then exposed to intratracheal (IT) vehicle or OVA on days 21–23. From day 20, vehicle, APD588 or FTY720 were dosed IT, QD. On day 24, methacholine-induced airway hyperresponsiveness (AHR), immune cell infiltration and BAL cytokines were measured. Results APD588 was a potent modulator of S1P1, with less potency at S1P4, 5, and no detectable activity at S1P2,3. IT administration of APD588 produced a dose-dependent inhibition of AHR, significantly inhibited airway eosinophil and lymphocyte infiltration, and BAL cytokines IL-4 and IL-5. FTY720 also reduced AHR and neutrophil and lymphocyte BAL cell counts, but had no effect on eosinophil counts or cytokines. Conclusions APD588 was an effective IT therapy for OVA-induced asthma. Lung function improvements correlated with reduced Th2 cytokines and lymphocyte and eosinophil infiltration in the BAL. Based on these results, APD588 may have therapeutic potential in asthma, and broadly indicate potential in other atopic Th2 diseases.

Critical role of CCL4 in eosinophil recruitment into the airway.

Excessive eosinophil airway infiltration is a clinically critical condition in some cases. Eosinophilic pneumonia (EP) is a pulmonary condition involving eosinophil infiltration of the lungs. Although several chemokines, including eotaxin-1 (CCL11), RANTES (CCL5) and macrophage inflammatory protein 1β (MIP-1β or CCL4), have been detected in bronchoalveolar lavage fluid (BALF) from patients with EP, the pathophysiological mechanisms underlying EP, including potential relationships between eosinophils and CCL4, have not been fully elucidated. To examine the involvement of CCL4 in eosinophilic airway inflammation. We analysed supernatants of activated eosinophils and BALF from 16 patients with eosinophilic pneumonia (EP). Further, we examined the effects of CCL4 on eosinophil functions in vitro and those of anti-CCL4 neutralizing antibody in an in vivo model. We found that purified human eosinophils stimulated with IL-5 predominantly secreted CCL4 and that patients with EP had elevated CCL11 and CCL4 levels in BALF compared with samples from individuals without EP. Because CCL4 levels were more strongly correlated with eosinophil count and expression of eosinophil granule proteins than CCL11, in vitro experiments using purified eosinophils concentrated on the former chemokine. Interestingly, CCL4 acted as a chemoattractant for eosinophils. In a mouse model, administration of a CCL4-neutralizing antibody attenuated eosinophilic airway infiltration and airway hyperresponsiveness. Overall, these findings highlight an important role of CCL4 in the mechanisms underlying eosinophil recruitment into the airway and may provide a novel insight into this potential therapeutic target.