Rhinovirus 16 3C Protease Induces Interleukin-8 and Granulocyte-Macrophage Colony-Stimulating Factor Expression in Human Bronchial Epithelial Cells

Abstract

Rhinovirus (RV), a member of the Picornaviridae family, accounts for many virus-induced asthma exacerbations. RV induces airway cell chemokine expression both in vivo and in vitro. Because of the known interactions of proteases with cellular functions, we hypothesized that RV 3C protease is sufficient for cytokine up-regulation. A cDNA encoding RV16 3C protease was constructed by PCR amplification and transfected into 16HBE14oϪ human bronchial epithelial cells. 3C protease induced expression of both IL-8 and GM-CSF, as well as transcription from both the IL-8 and GM-CSF promoters. 3C expression also induced activator protein 1 and NF-B transcriptional activation. Finally, mutation of IL-8 promoter AP-1 and NF-B promoter sequences significantly reduced 3C-induced responses. Together, these data suggest expression of RV16 3C protease is RVs are the most common upper respiratory pathogens, inducing the majority of common colds worldwide. Viral infections trigger asthma in 80 to 85% of asthma exacerbations in children and 44% in adults (1, 2) RV, a member of the Picornaviridae family of small, positive-stranded RNA viruses, accounts for much of virus-induced asthma exacerbations (1, 2). Cytokines are elaborated in vivo in the nasal mucosa, and most likely also from bronchial epithelium, after RV infection. Neutrophils, eosinophils, and lymphocytes increase in the nasal secretions of RV-infected patients compared with uninfected controls (3, 4).The cytokines IL-8 and GM-CSF have been implicated in the pathogenesis of asthma. IL-8 is a potent activator and chemoattractant of neutrophils (5) and eosinophils (6), and GM-CSF promotes the differentiation and survival of recruited eosinophils (7). Increased levels of IL-8, GM-CSF (8), and ICAM-1 (9), the receptor of 90% of RV serotypes, as well as IL-1 and IL-6, have been found in the nasal secretions of individuals infected with RVs (10 -12). In bronchial mucosal biopsies obtained after experimental infection with RV, Bardin and colleagues (13) noted a significant increase in submucosal lymphocytes and epithelial eosinophils, which, in asthmatics, persisted into convalescence. Although increases in cytokine secretion in the nasal mucosa does not prove increased expression in the epithelium in the lower airways, taken together the above data strongly suggest that cytokine elaboration is increased in the RV-infected lower airway epithelium.RV infection also induces cytokine production and adhesion molecule expression in cell culture. Divergent findings regard-

Rhinovirus-Induced MMP-9 Expression Is Dependent on Fra-1, Which Is Modulated by Formoterol and Dexamethasone

“…Fra-1 siRNA was then used to confirm a role for Fra-1 in HRVinduced MMP-9 expression. An increase in AP-1 transactivation has previously been reported in response to transfection of a construct expressing the rhinovirus 3C protease (38), although to our knowledge this is the first report to show that Fra-1 expression is inducible upon HRV infection of BEAS-2B cells. Whereas we saw a significant increase in Fra-1 expression in BEAS-2B cells, little to no induction of Fra-1 above baseline levels was noted upon HRV infection of primary HBE cells.…”

Phosphatidylinositol 3-Kinase Is Required for Rhinovirus-induced Airway Epithelial Cell Interleukin-8 Expression

“…The serine-threonine kinase inhibitor 2-aminopurine blocks double-stranded RNA-induced secretion of IL-8 (48). Previous work in this lab has shown that RV16 3C protease is sufficient to increase IL-8 response via NF-B activation (49).…”

Differential Processing of Nuclear Pore Complex Proteins by Rhinovirus 2A Proteases from Different Species and Serotypes

“…As the workhorse of every polyprotein-processing scheme, it contributes significantly to viral replication mechanisms (31) and synergistically to the host shutoff activities instigated by 2A pro or, e.g., the L proteins, which have similar antihost functions in other genera (11,23). 3C pro localizes to nuclei (2), cleaves crucial nuclear transcription factors (14), and participates (to a degree) in cellular cytokine regulation (12). These life cycle contributions are under investigation in a number of laboratories, and they are likely to show commonalities shared across many viruses. )…”