Cigarette smoke combined with Toll-like receptor 3 signaling triggers exaggerated epithelial regulated upon activation, normal T-cell expressed and secreted/CCL5 expression in chronic rhinosinusitis

Background

Chronic rhinosinusitis (CRS) is characterized by persistent mucosal inflammation and frequent exacerbations.

Objective

To determine whether innate epithelial responses to cigarette smoke or bacterial or viral pathogens may be abnormal in CRS leading to an inappropriate inflammatory response.

Methods

Primary nasal epithelial cells (PNECs) were grown from middle turbinate biopsies of 9 healthy controls and 11 patients with CRS. After reaching 80% to 90% confluence, PNECs were exposed to medium or cigarette smoke extract (CSE) 5% (vol/vol) for 1 hour, washed, then stimulated with staphylococcal lipoteichoic acid, LPS, or double-stranded RNA (dsRNA). After 24 hours, gene expression was quantified by QRT-PCR.

Results

At baseline, PNECs revealed elevated TNF-α and growth-related oncogene-α (a C-X-C chemokine)/CXCL1 (GRO-α) (4-fold increase, P = .02; and 16-fold increase, P = .004, respectively) in subjects with CRS compared with controls with normal levels of IL-1β, IL-6, IL-8/CXCL8, human β-defensin-2, monocyte chemoattractant protein 2/CCL8, monocyte chemoattractant protein 3/CCL7, and regulated upon activation, normal T-cell expressed and secreted (RANTES)/CCL5. Immunostaining of nasal biopsies, however, revealed comparable epithelial staining for TNF-α, GRO-α, and RANTES. There were no differences in mRNA induction by CSE, TNF-α, lipoteichoic acid, LPS, or dsRNA alone. The combination of CSE+dsRNA induced exaggerated RANTES (12,115-fold vs 1500-fold; P = .03) and human β-defensin-2 (1120-fold vs 12.5-fold; P = .05) in subjects with CRS. No other genes were differentially induced. Furthermore, CSE+dsRNA induced normal levels of IFN-β, IFN-λ1, and IFN-λ2/3 mRNA in subjects with CRS.

Conclusion

Cigarette smoke extract plus dsRNA induces exaggerated epithelial RANTES expression in patients with CRS. We propose that an analogous response to cigarette smoke plus viral infection may contribute to acute exacerbations and eosinophilic mucosal inflammation in CRS.

Key words: Chronic rhinosinusitis, epithelial, innate, cigarette smoke, viral, RANTES, exacerbations, eosinophilic

Abbreviations used: CRS, Chronic rhinosinusitis, CSE, Cigarette smoke extract, dsRNA, Double-stranded RNA (TLR-3 agonist), GAPDH, Glyceraldehyde-3-phosphate dehydrogenase (housekeeping gene), GRO-α, Growth-related oncogene-α (a C-X-C chemokine)/CXCL1, HBD2, Human β-defensin-2, HC, Healthy control, LTA, Lipoteichoic acid, MCP, Monocyte chemoattractant protein, RANTES, Regulated upon activation, normal T-cell expressed and secreted (a C-C chemokine)/CCL5, PNEC, Primary nasal epithelial cell, TLR, Toll-like receptor