Downregulation of caveolin-1 in chronic rhinosinusitis with and without nasal polyps.

The pathogenesis of human chronic rhinosinusitis (CRS) remains controversial. Recent evidence has suggested that caveolin-1 (Cav-1) is a 22 kDa scaffolding protein and plays a pivotal role in host defense against infections and tumour suppression by reducing production of cyclin D1 and endothelial nitric oxide-synthase (eNOS). However, little is known about their roles in CRS. Therefore, we aimed to investigate the expression and role of Cav-1 in CRS. Cav-1 protein expression were investigated by immunohistochemistry method and mRNA expression of Cav-1, cyclin D1 and eNOS were assessed by real-time polymerase chain reaction in CRS and control subjects. Moreover, the effects of various stimulators with different concentrations and time on Cav-1 were evaluated on nasal explant culture. The results showed that weaker expression of Cav-1 protein and mRNA were observed in CRS, especially in CRS with nasal polyps (CRSwNP), stronger mRNA expression of cyclin D1 and eNOS were observed in CRS and Cav-1 expression was negatively related to cyclin D1 and eNOS expression, respectively. Cav-1 mRNA was augmented by IFN-γ, but supressed by IL-4 and IL-1β. In conclusion, the expression of Cav-1 was downregulated in CRS and the role of Cav-1 was impaired in CRS, especially in CRSwNP, leading to the attenuation of inhibition effect on cyclin D1 and eNOS and resulted in the overexpression of cyclin D1 and eNOS. IFN-γ may be essential for Cav-1 gene expression.