No abstract

Virus infections are a major cause of chronic obstructive pulmonary disease (COPD) exacerbations. Recently, Toll-like receptor 3 (TLR3) has been demonstrated to react to double-stranded RNA (dsRNA) and to be involved in the immune responses after viral infections. In the present study, we examined whether oxidative stress, which is involved in the pathogenesis of COPD, enhances the responses of TLR3 in airway epithelial cells. The effect of hydrogen peroxide (H 2 O 2 ) on the release of IL-8 from BEAS-2B cells and primary human bronchial epithelial cells after stimulation with polyinosinepolycytidylic acid [poly(I:C)], a synthetic analog of viral dsRNA and a ligand for TLR3, and the signal transduction were examined. One hundred to 150 mM H 2 O 2 significantly potentiated the release of IL-8 from the epithelial cells after stimulation with 10 mg/ml poly(I:C). The H 2 O 2 -augmented IL-8 release was inhibited by treatment with N-acetylcysteine. One hundred micromoles of H 2 O 2 enhanced the translocation of nuclear factor (NF)-kB p65, but not that of interferon regulatory factor-3 (IRF-3), into the nucleus and the NF-kB DNA binding activity after poly(I:C) stimulation, which effect was inhibited not by the silencing of IRF-3 but by MG132, a proteasome inhibitor, or dexamethasone. One hundred micromoles of H 2 O 2 potentiated the TLR3 expression on the airway epithelial cells treated with poly(I:C). These data suggest that oxidative stress augments the response of TLR3 in airway epithelial cells via NF-kB and that this effect might be partly mediated by the enhancement of TLR3 expression. Modulation of this pathway may be a therapeutic target for viral-induced exacerbations of COPD.

Background: The DynaPort Activity Monitor (DAM) has been reported to be useful to evaluate the activity in healthy subjects and patients with chronic obstructive pulmonary disease (COPD). However, it is difficult to estimate the activity of COPD patients using DAM, because its battery works only for several hours and sensors should be worn at two parts of the body. A newly developed compact, single-position triaxial accelerometer (Actimarker) can measure the activity for >1 month, but has not been validated for COPD patients. Objectives: The validity of the Actimarker was evaluated in COPD patients. Methods: In study 1, the validity of the device was tested in 14 stable COPD patients by comparing it with DAM. In study 2, the influence of the weather on activity was examined. In study 3, the number of measurement days required to ensure repeatability was determined. Results: The durations of activity measured by the Actimarker and DAM were significantly correlated at intensity values ≧2.0, ≧2.5 and ≧3.0 METs. The duration of activity on rainy days was significantly shorter than that on non-rainy days. The values of intraclass correlation coefficients were >0.8 in 3-, 4- or 5-day measurements, and there was no systematic bias at any number of days or intensities with Bland-Altman plots. Conclusions: The validity of the Actimarker was confirmed, and repeatability was obtained when the data from at least 3 non-rainy weekdays were analyzed. Actimarker appears to be useful as a simplified method to evaluate the physical activity of COPD patients.

Because the pathophysiology of asthma has diverse characteristics, to manage the disease effectively, it is important for clinicians to distinguish among the clinical phenotypes. Among them, adult-onset asthma, that is, late-onset asthma (LOA), is increasing because of the aging of the population. The phenotype of LOA is largely divided into two types according to the presence or absence of eosinophilic inflammation, T-helper (Th)2- and non–Th2-associated LOA. Especially in Th2 LOA related to rhinosinusitis, as pulmonary function at onset is poor and asthma exacerbations occur frequently, it is important to detect this phenotype in the early phase by using a biomarker of Th2-type inflammation such as fractional exhaled nitric oxide (FENO). As non–Th2-LOA is often resistant to corticosteroids, this phenotype often requires another treatment strategy such as macrolide, diet, or smoking cessation. We often struggle with the management of LOA patients due to a lack of evidence; therefore, the elucidation of the mechanism of LOA contributes to increased efficiency of diagnosis and treatment of LOA. Age-related immune system and structural changes are thought to be associated with the pathophysiology of LOA. In the former case, changes in inflammatory cell function such as variations in the innate immune response and acquisition of autoimmunity or upregulation of oxidative stress are thought to be involved in the mechanism. Meanwhile, the latter can also become triggers or exacerbating factors of LOA via enhancement of airway hyperresponsiveness, decline in lung function, increased air trapping, and reduction in chest wall compliance. Therefore, appropriate individualized management in LOA may be possible through precisely assessing the pathophysiology based on age-related functional changes, including the immune and structural system.

Airway remodeling is observed in the airways of patients with asthma, and differentiation of fibroblasts to myofibroblasts plays a critical role in the progress of airway remodeling. Viral infection induces not only the disease development and exacerbations but also airway remodeling. The aim of this study was to evaluate whether the activation of Toll-like receptor 3 (TLR3) can affect the differentiation of fibroblasts to myofibroblasts and the extracellular matrix (ECM) protein production. Human fetal lung fibroblasts (HFL-1) and adult lung fibroblasts were treated with a synthetic double-stranded RNA, polyinosine-polycytidylic acid (poly[I:C]) and the expression of alpha-smooth muscle actin (alpha-SMA), a marker of myofibroblast differentiation, was evaluated. The release of transforming growth factor-beta(1) (TGF-beta(1)) and ECM protein production were assessed. The effect of anti-TGF-beta antibody on the alpha-SMA and ECM production was also assessed. Poly(I:C) significantly augmented the alpha-SMA expression (P < 0.01) and release of TGF-beta(1) (P < 0.01) compared with control. Bafilomycin, an inhibitor of TLR3 signaling, diminished poly(I:C)-augmented TGF-beta(1) release. Anti-TGF-beta(1) antibody inhibited the poly(I:C)-augmented alpha-SMA expression. Poly(I:C) enhanced translocation of nuclear factor-kB (NF-kappaB) and interferon regulatory factor-3 (IRF-3) into the nucleus. Poly(I:C)-augmented TGF-beta(1) release was almost completely blocked by NF-kappaB inhibitors, but not by silencing IRF-3. The production of fibronectin and collagen I expression were significantly increased by poly(I:C) (P < 0.01) and they were inhibited by anti-TGF-beta antibody. These results suggest that activation of TLR3 can affect the differentiation to myofibroblasts and enhance ECM production via the NF-kappaB-TGF-beta(1)-dependent pathway.

The cutoff values presented may be useful for the interpretation of FE(NO) values in the clinical practice.

Backgrounds: Inhaled corticosteroids (ICS)/inhaled long-acting beta2-agonists (LABA) combination drugs are widely used for the long-term management of chronic obstructive pulmonary disease (COPD). However, COPD is a heterogeneous condition and treatment with ICS is associated with a higher risk of pneumonia. The identification of a specific marker for predicting the efficacy of ICS/LABA on pulmonary function would be useful in the treatment of COPD. Methods: Fourteen COPD patients receiving tiotropium therapy participated consecutively. The relationship between the baseline exhaled nitric oxide (FENO) levels as well as serum markers and changes in pulmonary function by fluticasone propionate (FP)/salmeterol (SAL) were analyzed. Results: FP/SAL therapy significantly improved forced vital capacity, forced expiratory volume in 1 s (FEV1), and the third phase slope of the single nitrogen washout curve (ΔN2) as well as the FENO level. The baseline FENO levels and positive specific IgE (atopy+) were significantly associated with airway obstructive changes assessed by FEV1 and ΔN2. A baseline FENO level >35 ppb yielded 80.0% sensitivity and 66.7% specificity for identifying the subjects with significant improvement in FEV1 (greater than 200 mL). An atopy+ yielded 60.0% sensitivity and 88.9% specificity for an improvement in FEV1. When combined with FENO > 35 ppb and atopy+, it showed 40% sensitivity and 100.0% specificity for FEV1 improvement. Alternatively, COPD subjects with FENO ≤ 35 ppb and atopy− did not show significant improvement in FEV1. Conclusion: Combining FENO and specific IgE may be a useful marker for predicting the response to ICS/LABA on airflow limitation in COPD.

Background25-hydroxycholesterol (25-HC) is one of the oxysterols, which are oxidized derivatives of cholesterol, and has been reported to be involved in the pathogenesis of atherosclerosis and Alzheimer’s disease. In lung, the possible involvement of 25-HC in airway diseases has been revealed. In the present study, we examined whether 25-HC affects the release of cytokines and also modulates the responses of toll-like receptor 3 (TLR3) in airway epithelial cells.MethodsThe effect of 25-HC on the release of cytokines from primary human bronchial epithelial cells after stimulation with or without polyinosine-polycytidylic acid [poly(I:C)], a ligand for TLR3, and the signal transduction were examined.Results25-HC significantly potentiated the release of interleukin-8 (IL-8) and IL-6 from the cells. This effect was more potent compared with that of other oxysterols, 22-HC and 27-HC. GW3965 and TO901317, synthetic agonists of liver X receptors that are receptors for oxysterols, did not augment the IL-8 release. 25-HC enhanced the nuclear factor-kappa B (NF-κB) DNA binding activity and translocation of phosphorylated c-Jun into the nucleus. The release of IL-8 was inhibited by the NF-κB inhibitor, caffeic acid phenethyl ester (CAPE), an inhibitor of nuclear factor kappa-B alpha (IκBα) inhibitor, BAY 11–7085, and an inhibitor of nuclear factor kappa-B kinase-2 (IKK-2) inhibitor, SC-514, but not by a c-Jun N-terminal kinase (JNK) inhibitory peptide, L-JNKi1. 25-HC significantly potentiated IL-8 release in poly(I:C)-treated cells and the augmentation was inhibited by CAPE, BAY 11–7085, and SC-514. Furthermore, 25-HC potentiated the translocation of interferon regulatory factor 3 into the nucleus and the release of interferon-beta (IFN-β) in poly(I:C)-treated cells.ConclusionsThese data demonstrated that 25-HC augments the release of IL-8 and IL-6 via NF-κB signalling pathway and enhances the release of IL-8 and IFN-β after stimulation of TLR3 in airway epithelial cells. 25-HC may be involved in the neutrophilic airway inflammation through the stimulant effect of IL-8 and IL-6 release and also potentiate the TLR3-mediated innate immunity in airway diseases.