Role of Caffeic Acid on Collagen Production in Nasal Polyp-Derived Fibroblasts

ABSTRACT

OBJECTIVES: Caffeic acids are known to have anti-oxidant, anti-inflammatory, immunomodulatory, and tissue reparative effects. The purposes of this study were to determine the effect of caffeic acid on transforming growth factor (TGF) beta1-induced myofibroblast differentiation and collagen production, and to determine whether caffeic acid is involved in the antioxidant effect in nasal polyp-derived fibroblasts (NPDFs). METHODS: NPDFs were pretreated with caffeic acid (1-10 microM) for 2 hours and stimulated with TGF-beta1 (5 ng/mL) for 24 hours. The expression of alpha-smooth muscle actin (SMA), collagen types I and III, and Nox4 mRNA was determined by a reverse transcription-polymerase chain reaction, and the expression of alpha-SMA protein was determined by actin ned by immunofluorescence microscopy. The amount of total soluble collagen production was analyzed by the Sircol collagen dye-binding assay. The reactive oxygen species (ROS) generated by NPDFs were determined using 2',7'-dichlorfluorescein-diacetate. siNox4 was used to determine the effect of Nox4. RESULTS: The expression of alpha-SMA and production of collagen were significantly increased following TGF-beta1 treatment. In contrast, the level of expression of alpha-SMA and the level of production of collagen were decreased by pretreatment with caffeic acid. The activation of Nox4 and the subsequent production of ROS were also reduced by pretreatment with caffeic acid. The expression of alpha-SMA was prevented by inhibition of ROS generation with siNox4. CONCLUSION: Caffeic acid may inhibit TGF-beta1-induced differentiation of fibroblasts into myofibroblasts and collagen production by regulating ROS.