Human rhinovirus (HRV) infections trigger acute exacerbations of chronic obstructive pulmonary disease (COPD) and asthma. The human airway epithelial cell is the primary site of HRV infection and responds to infection with altered expression of multiple genes, the products of which could regulate the outcome to infection. Cigarette smoking aggravates asthma symptoms, and is also the predominant risk factor for the development and progression of COPD. We, therefore, examined whether cigarette smoke extract (CSE) modulates viral responses by altering HRV-induced epithelial gene expression. Primary cultures of human bronchial epithelial cells were exposed to medium alone, CSE alone, purified HRV-16 alone or to HRV-16+ CSE. After 24 h, supernatants were collected and total cellular RNA was isolated. Gene array analysis was performed to examine mRNA expression. Additional experiments, using real-time RT-PCR, ELISA and/or western blotting, validated altered expression of selected gene products. CSE and HRV-16 each induced groups of genes that were largely independent of each other. When compared to gene expression in response to CSE alone, cells treated with HRV+CSE showed no obvious differences in CSE-induced gene expression. By contrast, compared to gene induction in response to HRV-16 alone, cells exposed to HRV+CSE showed marked suppression of expression of a number of HRV-induced genes associated with various functions, including antiviral defenses, inflammation, viral signaling and airway remodeling. These changes were not associated with altered expression of type I or type III interferons. Thus, CSE alters epithelial responses to HRV infection in a manner that may negatively impact antiviral and host defense outcomes.

Human rhinovirus (HRV) infections up-regulate proinflammatory mediators and growth factors that are associated with exacerbations of inflammatory airway diseases, such as asthma and chronic obstructive pulmonary disease (COPD). Matrix metalloproteinase (MMP)-9 was shown to be increased in the airways of patients with asthma and COPD. We sought to determine whether HRV infection modulated the expression of MMP-9 and its highest-affinity inhibitor, the tissue inhibitor of metalloproteinase (TIMP)-1, and we explored the mechanism by which this modulation occurs. In vitro studies, using RT-PCR, ELISA, zymography, and a fluorescent activity assay, demonstrated that MMP-9 mRNA, protein, and activity were increased upon infection with HRV, whereas TIMP-1 mRNA and protein remained unchanged. These results were verified in vivo, using nasal lavage samples obtained from subjects with confirmed rhinovirus infections. Human rhinovirus infections were shown to up-regulate NF-kB, and NF-kB has also been reported to play a role in the expression of MMP-9. We therefore investigated the role of NF-kB in HRV-induced MMP-9 expression. Using two inhibitors of IkBa kinase b, we observed a concentration-dependent decrease in HRVinduced MMP-9 expression. The role of NF-kB in HRV-induced MMP-9 expression was further confirmed using MMP-9 promoter luciferase constructs, which demonstrated that an NF-kB site at 2620/2607 base pairs was necessary for HRV-induced MMP-9 expression. Electrophoretic mobility shift assays and supershift assays confirmed the nuclear translocation and binding of p50/p65 NF-kB subunits to an MMP-9-specific NF-kB oligonucleotide. This increase in MMP-9 may be a mechanism by which rhinovirus infections contribute to airway inflammation and, potentially, to airway remodeling.Keywords: airway epithelial cell; airway inflammation; airway remodeling; human rhinovirus; matrix metalloproteinase-9Human rhinovirus (HRV) infections are associated with exacerbations of lower airway diseases, such as asthma and chronic obstructive pulmonary disease (COPD) (1). More than 100 serotypes of HRV exist, and they may be grouped according to the cell surface receptor used to gain entry into airway epithelial cells, which are their primary site of infection (2, 3). More than 90% of these HRV serotypes belong to the major group that attaches to the host cell via intercellular adhesion molecule-1, whereas at least 10 serotypes belong to the minor group and use members of the low-density lipoprotein receptor family for attachment (4).Although HRV infections are strongly linked to exacerbations of asthma and COPD, the mechanisms by which such infections cause these exacerbations are not yet fully characterized. It was demonstrated that the HRV infection of airway epithelial cells in vitro induces the production of various cytokines, chemokines, growth factors, and host defense proteins, several of which are also detected in airway secretions during in vivo HRV infections (5, 6). According to the current paradigm, these cellular products s...

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Matrix metalloproteinase-9 is implicated in airway inflammation and airway remodeling in asthma. We have previously confirmed that human rhinovirus-16 (HRV-16) infection increases MMP-9 expression both in vivo and in vitro. However, the role of the AP-1 sites within the MMP-9 promoter and the effect of commonly used asthma pharmacotherapies in modulating human rhinovirus (HRV)-induced MMP-9 production have not yet been elucidated. Experiments were performed in vitro in the human bronchial epithelial (HBE) cell line BEAS-2B and in primary HBE cells obtained from non-transplanted lungs. Using site-directed mutagenesis approaches, AP-1 sites were found to be necessary for HRV-induced MMP-9 promoter drive. EMSAs and supershift assays identified complexes consisting of Fos-related Ag-1 (Fra-1) in addition to other AP-1 subunits. Small interfering RNA approaches indicated that Fra-1 was induced upon HRV-16 infection in BEAS-2B cells and was necessary for MMP-9 expression in both BEAS-2B and primary HBE cells. Inhibition of MEK1/2 activity using PD98059 and U0126 reduced Fra-1 expression, DNA binding, MMP-9 promoter drive, and MMP-9 protein production. The long-acting β2-agonist formoterol and the glucocorticoid dexamethasone significantly reduced HRV-induced ERK phosphorylation, Fra-1, and MMP-9 expression in BEAS-2B cells. These data indicate that HRV-induced activation of the MEK/ERK MAPK pathway and Fra-1 expression are necessary for the upregulation of MMP-9 and can be modulated by two distinct but commonly used asthma pharmacotherapies. Together, these results offer insights into the mechanisms by which long-acting β2-agonists and glucocorticoids might reduce HRV-related asthma exacerbations.

Clinical research bridges patients' unmet medical need with innovative medicines, increases knowledge acquisition by clinicians, and creates solutions to improve the sustainability and quality of the Canadian health care system and economy. The Canadian Institutes of Health Research and the Canadian Lung Association have recently raised concerns over declining research activities within the Canadian respiratory community. While there are currently >3000 ongoing clinical trials in Canada, the number of trials investigating common respiratory diseases is unknown. The objective of the present study was to monitor the trends in industry- and non-industry-sponsored respiratory clinical trials in Canada from 2001 to 2011. Trialtrove 2012 (Citeline, an Informa UK business), a database containing summarized clinical trial information regarding pharmaceutical products, was searched using common chronic respiratory disease terms: "allergic rhinitis", "asthma", "chronic obstructive pulmonary disease (COPD)", "cystic fibrosis", "respiratory infections", "pulmonary fibrosis" and "smoking cessation". Over the past 10 years, the number of respiratory clinical trials conducted in Canada has increased (4.49 per year; P=0.004). From 2001 to 2011, the majority of trials were performed in asthma, followed closely by respiratory infections and COPD. Over the past decade, the number of trials investigating COPD and respiratory infections increased (P<0.05), while asthma trials showed a declining trend since 2007. Of the clinical trials performed during this 10-year period, the majority were in phase III, with a significant increase in the number of phase II trials (2.49 per year; P=0.008). However, certain trends observed are concerning and warrant further monitoring in the coming years.