The Up-Regulated Expression of Tenascin C in Human Nasal Polyp Tissues is Related to Eosinophil-Derived Transforming Growth Factor β1

Abstract

Background Tissue remodeling is an important characteristic of nasal polyps (NPs). However, the mechanisms underlying the remodeling processes are poorly defined. This study investigated the role of transforming growth factor (TGF) β1 and eosinophils in the expression of tenascin C (Tn-C), an extracellular matrix glycoprotein, in NPs. Methods The protein expression of Tn-C and TGF-β1 was examined by means of immunohistochemistry in NPs and normal control inferior turbinate tissues. Furthermore, cell culture, quantitative RT-PCR, and in situ immunocytofluorescence techniques were used to investigate the direct effect of TGF-β1 and eosinophils on Tn-C production in primary nasal epithelial cells. Results Tn-C protein expression was significantly up-regulated in NP tissues and correlated with TGF-β1+ eosinophils. TGF-β1 and eosinophils dramatically induced Tn-C mRNA and protein expression in nasal epithelial cells. The effect of eosinophils could be inhibited partly by a neutralizing antibody to TGF-β1. Conclusion Eosinophil-derived TGF-β1 may contribute, at least in part, to the tissue remodeling in NPs.