Prevalence of airflow limitation in Japan is higher than previously reported, suggesting a high degree of under-recognition of COPD. The high prevalence of smoking coupled with an aging population threatens to further increase the burden of COPD, highlighting the need for enhanced screening efforts and interventions of prevention and treatment.

Idiopathic interstitial pneumonias (IIPs) are histopathologically classified into several types, including usual interstitial pneumonia (UIP), nonspecific interstitial pneumonia (NSIP) and cryptogenic organising pneumonia (COP). We investigated whether periostin, a matrix protein, could be used as a biomarker to assess histopathological types of IIPs.We performed immunohistochemical analyses in each histopathological type of IIP, examined serum levels of periostin in IIP patients and analysed the relationship between serum levels of periostin and the pulmonary functions in patients with idiopathic pulmonary fibrosis (IPF).Periostin was strongly expressed in lungs of UIP and fibrotic NSIP patients, whereas expression of periostin was weak in the lungs of cellular NSIP and COP patients, as well as in normal lungs. Serum levels of periostin in IPF were significantly higher than those of healthy subjects and COP patients. Furthermore, periostin levels in IPF patients were inversely correlated with their pulmonary functions.Thus, we have found that periostin is a novel component of fibrosis in IIP. Periostin may be a potential biomarker to distinguish IIP with fibrosis.

Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive, and usually fatal form of interstitial lung disease (ILD). The precise molecular mechanisms of IPF remain poorly understood. However, analyses of mice receiving bleomycin (BLM) as a model of IPF established the importance of preceding inflammation for the formation of fibrosis. Periostin is a recently characterized matricellular protein involved in modulating cell functions. We recently found that periostin is highly expressed in the lung tissue of patients with IPF, suggesting that it may play a role in the process of pulmonary fibrosis. To explore this possibility, we administered BLM to periostin-deficient mice, and they subsequently showed a reduction of pulmonary fibrosis. We next determined whether this result was caused by a decrease in the preceding recruitment of neutrophils and macrophages in the lungs because of the lower production of chemokines and proinflammatory cytokines. We performed an in vitro analysis of chemokine production in lung fibroblasts, which indicated that periostin-deficient fibroblasts produced few or no chemokines in response to TNF-α compared with control samples, at least partly explaining the lack of inflammatory response and, therefore, fibrosis after BLM administration to periostin-deficient mice. In addition, we confirmed that periostin is highly expressed in the lung tissue of chemotherapeutic-agent-induced ILD as well as of patients with IPF. Taking these results together, we conclude that periostin plays a unique role as an inducer of chemokines to recruit neutrophils and macrophages important in the process of pulmonary fibrosis in BLM-administered model mice. Our results suggest a therapeutic potential for periostin in IPF and drug-induced ILD.

Excessive production of airway mucus is a cardinal feature of bronchial asthma and chronic obstructive pulmonary disease (COPD) and contributes to morbidity and mortality in these diseases. IL-13, a Th2-type cytokine, is a central mediator in the pathogenesis of bronchial asthma, including mucus overproduction. Using a genome-wide search for genes induced in airway epithelial cells in response to IL-13, we identified pendrin encoded by the SLC26A4 (PDS) gene as a molecule responsible for airway mucus production. In both asthma and COPD mouse models, pendrin was up-regulated at the apical side of airway epithelial cells in association with mucus overproduction. Pendrin induced expression of MUC5AC, a major product of mucus in asthma and COPD, in airway epithelial cells. Finally, the enforced expression of pendrin in airway epithelial cells in vivo, using a Sendai virus vector, rapidly induced mucus overproduction in the lumens of the lungs together with neutrophilic infiltration in mice. These findings collectively suggest that pendrin can induce mucus production in airway epithelial cells and may be a therapeutic target candidate for bronchial asthma and COPD.

B7-H1 (PD-L1) and B7-DC (PD-L2) are the ligands for programmed death-1 (PD-1), which is a member of the CD28/CTLA-4 family and has been implicated in peripheral tolerance. We investigated the roles of B7-H1 and B7-DC in a murine OVA-induced allergic asthma model. B7-H1 was constitutively expressed on dendritic cells, macrophages, B cells, and T cells in the lungs of naive mice, and its expression could be dramatically increased after allergen challenge. In contrast, B7-DC expression was scarcely expressed on dendritic cells in naive mice, but was up-regulated after allergen challenge, although the up-regulation of B7-DC expression on macrophages was minimal. Treatment of mice with anti-B7-DC mAb at the time of allergen challenge, but not at the time of sensitization, significantly increased their airway hyper-reactivity and eosinophilia. Such treatment also resulted in the increased production of IL-5 and IL-13, and decreased IFN-γ production in the lungs and draining lymph node cells. These changes were diminished when mice were depleted of IFN-γ by anti-IFN-γ mAb pretreatment. Interestingly, treatment with anti-B7-H1 or anti-PD-1 mAb did not significantly affect the asthmatic response. These results suggest a unique role for B7-DC in the regulation of asthmatic response through an IFN-γ-dependent, but PD-1-independent, mechanism.

Administration of several chemotherapeutic drugs, such as bleomycin, busulfan, and gefitinib, often induces lethal lung injury. However, the precise mechanisms responsible for this drug-induced lung injury are still unclear. In the present study, we examined the role of the proinflammatory cytokines IL-18 and IL-1beta in the mechanism of bleomycin-induced lung injury. We performed immunohistochemical analysis of IL-18 and IL-18 receptor (R) alpha chain expression in the lungs of five patients with bleomycin-induced lethal lung injury. Enhanced expression of both IL-18 and IL-18Ralpha was observed in the lungs of all five patients with bleomycin-induced lung injury. To support the data obtained from patient samples, the levels of IL-1beta and IL-18 mRNA and protein, pulmonary inflammation, and lung fibrosis were examined in mouse models of bleomycin-induced lung injury. Intravenous administration of bleomycin induced the expression of IL-1beta and IL-18 in the serum and lungs of wild-type C57BL/6 mice. IL-18-producing F4/80(+) neutrophils, but not CD3(+) T cells, were greatly increased in the lungs of treated mice. Moreover, bleomycin-induced lung injury was significantly attenuated in caspase-1(-/-), IL-18(-/-), and IL-18Ralpha(-/-) mice in comparison with control mice. Thus, our results provide evidence for an important role of IL-1beta and IL-18 in chemotherapy-induced lung injury.

Interleukin (IL)-18 production and pulmonary function were evaluated in patients with chronic obstructive pulmonary disease (COPD) in order to determine the role of IL-18 in COPD.Immunohistochemical techniques were used to examine IL-18 production in the lungs of patients with very severe COPD (Global Initiative for Chronic Obstructive Lung Disease (GOLD) stage IV, n516), smokers (n527) and nonsmokers (n523). Serum cytokine levels and pulmonary function were analysed in patients with GOLD stage I-IV COPD (n562), smokers (n534) and nonsmokers (n547).Persistent and severe small airway inflammation was observed in the lungs of ex-smokers with very severe COPD. IL-18 proteins were strongly expressed in alveolar macrophages, CD8+ Tcells, and both the bronchiolar and alveolar epithelia in the lungs of COPD patients. Serum levels of IL-18 in COPD patients and smokers were significantly higher than those in nonsmokers. Moreover, serum levels of IL-18 in patients with GOLD stage III and IV COPD were significantly higher than in smokers and nonsmokers. There was a significant negative correlation between serum IL-18 level and the predicted forced expiratory volume in one second in patients with COPD. In contrast, serum levels of IL-4, IL-13 and interferon-c were not significantly increased in any of the three groups.In conclusion, overproduction of interleukin-18 in the lungs may be involved in the pathogenesis of chronic obstructive pulmonary disease.

Purpose: Therapeutic responses of non-small cell lung carcinoma (NSCLC) to epidermal growth factor receptor (EGFR)-targeted drugs, such as gefitinib and erlotinib, are closely associated with activating EGFR mutations. The most common mutations are delE746-A750 in exon 19 and L858R in exon 21, accounting for ∼90% of all EGFR mutations. Recently, EGFR mutation-specific antibodies were developed and did well in immunohistochemical analysis, giving a sensitivity of ∼90%. We have investigated whether this method detects activating EGFR mutations with sensitivity comparable with direct DNA sequencing, which is used to detect these mutations in NSCLC.Experimental Design: We used antibodies specific for the E746-A750 deletion mutation in exon 19 and the L858R point mutation in exon 21 in Western blot analysis and immunohistochemistry to determine the presence of these mutations in NSCLC cell lines. We also examined these EGFR mutations in NSCLC tumor samples from 60 patients by immunohistochemically and direct DNA sequencing.Results: We were able to identify EGFR mutations in NSCLC tumor samples immunohistochemically with a sensitivity of 79% using the anti-delE746-A750 antibody and 83% using the anti-L858R antibody. Additional DNA sequencing markedly improved the sensitivity obtained by immunohistochemistry.Conclusions: This simple and rapid assay for detecting EGFR mutations, even in the small bronchial biopsies obtained in stage IV NSCLC patients, will be useful for diagnosing responsiveness to EGFRtargeted drugs in patients with NSCLC. Combining this with DNA sequencing is recommended for the development of improved personalized EGFR-targeted therapeutics.