Keratinocyte growth factor down-regulates intracellular ROS production induced by UVB

Background: Exposure to ultraviolet (UV) radiation causes a complex cellular response, mostly mediated by the production of reactive oxygen species (ROS), which can be counteracted by exogenous treatments and endogenous mechanisms with anti-oxidant and scavenger properties. Keratinocyte growth factor (KGF/FGF7), a member of the fibroblast growth factor family, promotes epithelial growth and differentiation and is involved in cell survival after oxidant injuries. Objective: We analyzed the role of KGF in the control of intracellular ROS production and oxidative stress after UVB exposure on KGF receptor (KGFR) transfected cells and human immortalized and primary keratinocytes. Methods: We assessed the intracellular ROS production measuring the intensity of the oxidation-sensitive fluorescent probe 2′,7′-dichlorofluorescein diacetate (DCFH-DA) by confocal microscopy, as well as the catalase activity by spectrophotometric assay. Moreover, morphological and biochemical analysis of actin cytoskeleton reorganization was evaluated as a further marker of oxidative damage. Results: Our data show that KGF significantly reduces intracellular ROS generation in response to UVB, preserves the decrease of catalase activity and prevents actin cytoskeleton rearrangement. Conclusion: Our results provide a further evidence that KGF may be crucial for an efficient skin photoprotection, demonstrating a direct role for KGF in the reduction of intracellular ROS content following UVB exposure.