Downregulation of Integrin β4 Decreases the Ability of Airway Epithelial Cells to Present Antigens

Airway epithelial cells have been demonstrated to be accessory antigen presentation cells (APC) capable of activating T cells and may play an important role in the development of allergic airway inflammation of asthma. In asthmatic airways, loss of expression of the adhesion molecule integrin β4 (ITGB4) and an increase in Th2 inflammation bias has been observed in our previous study. Given that ITGB4 is engaged in multiple signaling pathways, we studied whether disruption of ITGB4-mediated cell adhesion may contribute to the adaptive immune response of epithelial cells, including their ability to present antigens, induce the activate and differentiate of T cells. We silenced ITGB4 expression in bronchial epithelial cells with an effective siRNA vector and studied the effects of ITGB4 silencing on the antigen presentation ability of airway epithelial cells. T cell proliferation and cytokine production was investigated after co-culturing with ITGB4-silenced epithelial cells. Surface expression of B7 homologs and the major histocompatibility complex (MHC) class II was also detected after ITGB4 was silenced. Our results demonstrated that silencing of ITGB4 resulted in impaired antigen presentation processes and suppressed T cell proliferation. Meanwhile, decrease in Th1 cytokine production and increase in Th17 cytokine production was induced after co-culturing with ITGB4-silenced epithelial cells. Moreover, HLA-DR was decreased and the B7 homologs expression was different after ITGB4 silencing. Overall, this study suggested that downregulation of ITGB4 expression in airway epithelial cells could impair the antigen presentation ability of these cells, which further regulate airway inflammation reaction in allergic asthma

The biodiversity hypothesis and allergic disease: world allergy organization position statement

Peer reviewe

A randomised controlled study of the effectiveness of breathing retraining exercises taught by a physiotherapist either by instructional DVD or in face-to-face sessions in the management of asthma in adults.

BACKGROUND: Asthma control is suboptimal, resulting in quality of life (QoL) impairment and costs. Breathing retraining exercises have evidence of effectiveness as adjuvant treatment, but are infrequently used. OBJECTIVES: To transfer the contents of a brief (three-session) physiotherapist-delivered breathing retraining programme to a digital versatile disc (DVD) and booklet format; to compare the effectiveness of the self-guided intervention with that of 'face-to-face' physiotherapy and usual care for QoL and other asthma-related outcomes; to perform a health economic assessment of both interventions; and to perform a process evaluation using quantitative and qualitative methods. DESIGN: Parallel-group three-arm randomised controlled trial. SETTING: General practice surgeries in the UK. PARTICIPANTS: In total, 655 adults currently receiving asthma treatment with impaired asthma-related QoL were randomly allocated to the DVD (n = 261), physiotherapist (n = 132) and control (usual care) (n = 262) arms in a 2 : 1 : 2 ratio. It was not possible to blind participants but data collection and analysis were performed blinded. INTERVENTIONS: Physiotherapy-based breathing retraining delivered through three 'face-to-face' respiratory physiotherapist sessions or a self-guided programme (DVD plus our theory-based behaviour change booklet) developed by the research team, with a control of usual care. MAIN OUTCOME MEASURES: The primary outcome measure was asthma-specific QoL, measured using the Asthma Quality of Life Questionnaire (AQLQ). Secondary outcomes included asthma symptom control [Asthma Control Questionnaire (ACQ)], psychological state [Hospital Anxiety and Depression Scale (HADS)], hyperventilation symptoms (Nijmegen questionnaire), generic QoL [EuroQol-5 Dimensions (EQ-5D)], assessments of airway physiology (spirometry) and inflammation (exhaled nitric oxide) and health resource use and costs. Assessments were carried out at baseline and at 3, 6 and 12 months post randomisation. Patient engagement and experience were also assessed using quantitative and qualitative methods. RESULTS: Primary efficacy analysis was between-group comparison of changes in AQLQ scores from baseline to 12 months in the intention-to-treat population with adjustments for prespecified covariates. Significant improvements occurred in the DVD group compared with the control group [adjusted mean difference 0.28, 95% confidence interval (CI) 0.11 to 0.44; p < 0.001] and in the face-to-face physiotherapy group compared with the control group (adjusted mean difference 0.24, 95% CI 0.04 to 0.44; p < 0.05), with equivalence between the DVD and the face-to-face physiotherapy groups (adjusted mean difference 0.04, 95% CI -0.16 to 0.24). In all sensitivity analyses, both interventions remained significantly superior to the control and equivalence between the interventions was maintained. In other questionnaire outcome measures and in the physiological measures assessed, there were no significant between-group differences. Process evaluations showed that participants engaged well with both of the active interventions, but that some participants in the DVD arm would have liked to receive tuition from a professional. Asthma health-care costs were lower in both intervention arms than in the control group, indicating 'dominance' for both of the interventions compared with the control, with lowest costs in the DVD arm. The rate of adverse events was lower in the DVD and face-to-face physiotherapy groups than in the control group. CONCLUSIONS: Only 10% of the potentially eligible population responded to the study invitation. However, breathing retraining exercises improved QoL and reduced health-care costs in adults with asthma whose condition remains uncontrolled despite standard pharmacological therapy, were engaged with well by patients and can be delivered effectively as a self-guided intervention. The intervention should now be transferred to an internet-based platform and implementation studies performed. Interventions for younger patients should be developed and trialled. TRIAL REGISTRATION: Current Controlled Trials ISRCTN88318003. FUNDING: This project was primarily funded by the NIHR Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 21, No. 53. See the NIHR Journals Library website for further project information. Additional financial support was received from Comprehensive Local Research Networks

Smoking in asthma is associated with elevated levels of corticosteroid resistant sputum cytokines—an exploratory study

&lt;p&gt;Background: Current cigarette smoking is associated with reduced acute responses to corticosteroids and worse clinical outcomes in stable chronic asthma. The mechanism by which current smoking promotes this altered behavior is currently unclear. Whilst cytokines can induce corticosteroid insensitivity in-vitro, how current and former smoking affects airway cytokine concentrations and their responses to oral corticosteroids in stable chronic asthma is unclear.&lt;/p&gt; &lt;p&gt;Objectives: To examine blood and sputum cytokine concentrations in never, ex and current smokers with asthma before and after oral corticosteroids.&lt;/p&gt; &lt;p&gt;Methods: Exploratory study utilizing two weeks of oral dexamethasone (equivalent to 40 mg/day prednisolone) in 22 current, 21 never and 10 ex-smokers with asthma. Induced sputum supernatant and plasma was obtained before and after oral dexamethasone. 25 cytokines were measured by multiplex microbead system (Invitrogen, UK) on a Luminex platform.&lt;/p&gt; &lt;p&gt;Results: Smokers with asthma had elevated sputum cytokine interleukin (IL) -6, -7, and -12 concentrations compared to never smokers with asthma. Few sputum cytokine concentrations changed in response to dexamethasone IL-17 and IFNα increased in smokers, CCL4 increased in never smokers and CCL5 and CXCL10 reduced in ex-smokers with asthma. Ex-smokers with asthma appeared to have evidence of an ongoing corticosteroid resistant elevation of cytokines despite smoking cessation. Several plasma cytokines were lower in smokers wi&lt;/p&gt; &lt;p&gt;Conclusion: Cigarette smoking in asthma is associated with a corticosteroid insensitive increase in multiple airway cytokines. Distinct airway cytokine profiles are present in current smokers and never smokers with asthma and could provide an explanatory mechanism for the altered clinical behavior observed in smokers with asthma.&lt;/p&gt

Chronic Respiratory Aeroallergen Exposure in Mice Induces Epithelial-Mesenchymal Transition in the Large Airways

Chronic allergic asthma is characterized by Th2-polarized inflammation and leads to airway remodeling and fibrosis but the mechanisms involved are not clear. To determine whether epithelial-mesenchymal transition contributes to airway remodeling in asthma, we induced allergic airway inflammation in mice by intranasal administration of house dust mite (HDM) extract for up to 15 consecutive weeks. We report that respiratory exposure to HDM led to significant airway inflammation and thickening of the smooth muscle layer in the wall of the large airways. Transforming growth factor beta-1 (TGF-β1) levels increased in mouse airways while epithelial cells lost expression of E-cadherin and occludin and gained expression of the mesenchymal proteins vimentin, alpha-smooth muscle actin (α-SMA) and pro-collagen I. We also observed increased expression and nuclear translocation of Snail1, a transcriptional repressor of E-cadherin and a potent inducer of EMT, in the airway epithelial cells of HDM-exposed mice. Furthermore, fate-mapping studies revealed migration of airway epithelial cells into the sub-epithelial regions of the airway wall. These results show the contribution of EMT to airway remodeling in chronic asthma-like inflammation and suggest that Th2-polarized airway inflammation can trigger invasion of epithelial cells into the subepithelial regions of the airway wall where they contribute to fibrosis, demonstrating a previously unknown plasticity of the airway epithelium in allergic airway disease

Using models of the ocean's mean dynamic topography to identify errors in coastal geodetic levelling

Identifying errors (blunders and systematic errors) in coastal geodetic levelling networks has often been problematic. This is because (1) mean sea level (MSL) at tide gauges cannot be directly compared to height differences from levelling because the geoid/quasigeoid and MSL are not parallel, being separated by the ocean’s mean dynamic topography (MDT) and (2) the lack of redundancy at the edge of the levelling network. This paper sets out a methodology to independently identify blunders and/or systematic errors (over long distances) in geodetic levelling using MDT models to account for the separation between the geoid/quasigeoid and MSL at tide gauges. This method is then tested in a case study using an oceanographic MDT model, MSL observations, GNSS data and a quasigeoid model. The results are significant because the errors found could not be detected by standard levelling misclosure checks alone, with supplementary data from an MDT model, with cross-validation from GNSS-quasigeoid allowing their detection. In addition, it appears that an oceanographic-only MDT is as effective as GNSS and a quasigeoid model for detecting levelling errors, which could be particularly useful for countries with coastal levelling errors in their levelling networks that cannot be identified by conventional levelling closure checks