Interleukin-19 upregulates fibronectin and collagen I expression via the NF-κB-Smad2/3 pathway in fibroblasts of patients with chronic rhinosinusitis

Background Tissue remodeling is a prominent characteristic of chronic rhinosinusitis (CRS). Excess deposition of fibronectin (FN) and collagen (Col) I by fibroblasts is crucial for the pathologic tissue remodeling in CRS without nasal polyps (CRSsNP). Increased interleukin (IL)-19 level in patients with CRS had been demonstrated in our previous studies. Here, we aimed to evaluate the role of IL-19 in mediating FN and Col I expression in CRS. Methods Nasal mucosal tissue samples were collected from patients with CRS with nasal polyps (CRSwNP), CRSsNP, and controls. The expression of IL-19, vimentin, FN, and Col I were detected using immunohistochemistry and immunofluorescence. Primary human nasal fibroblasts were treated with IL-19, then the activation of Smad2/3, NF-kappa B and relevant pathways, and the expression of FN and Col I were measured. Results Expression levels of vimentin, FN, and Col I were significantly increased in nasal tissues from patients with CRSsNP compared with CRSwNP and control subjects. Moreover, IL-19 co-localized with FN and Col Iota in nasal tissues. IL-19-treated fibroblasts had increased production of FN and Col I, which was associated with the activated Smad2/3 and NF-kappa B pathways. Moreover, Smad2/3 activation was mediated by the NF-kappa B pathway in IL-19-treated fibroblasts. Conclusions IL-19 promotes FN and Col I production via the activated NF-kappa B-Smad2/3 pathway in fibroblasts, leading to fibrosis and collagen deposition in patients with CRS.