Interleukin-4 and interleukin-13 induce fibronectin production by human lung fibroblasts

Interleukin (IL)-4 and IL-13, which play a role in the production of allergic inflammation, can activate fibroblasts to elicit a variety of cellular functions. However, the effect of IL-4 and IL-13 on fibronectin production by human lung fibroblasts (HLF) has not been determined. In the present study, we examined the effect of IL-4 and IL-13 on fibronectin production by HLF in order to clarify these issues. We stimulated HLF with various concentrations of IL-4 and IL-13 for 12, 24, 48 and 72 h and fibronectin concentrations in the culture supernatants were determined by ELISA The results showed that IL-4 and IL-13 induced fibronectin production in a time- and a concentration-dependent manner. Anti-transforming growth factor (TGF)β1 antibody (ab) inhibited TGF-β1 induced fibronectin production but not IL-4- and IL-1 3-induced fibronectin production, indicating that TGF-β1 is not involved in the IL-4- and IL-13-induced fibronectin production by HLF. These results indicate that IL-4 and IL-13 are capable of inducing fibronectin production by HLF and play an important role in the production of airway remodeling by inducing fibronectin production as well as allergic inflammation.