TRPV2 channel inhibitors attenuate fibroblast differentiation and contraction mediated by keratinocyte-derived TGF-β1 in an in vitro wound healing model of rats

Abstract Background Keratinocytesrelease several factors that are involved in wound contractureand scar formation. We previously reported that a three-dimensional reconstruction model derived from rat skin represents a good wound healing model. Objective We characterized the role of transient receptor potential(TRP) channels in the release of transforming growth factor (TGF)-β1 from keratinocytesand the differentiation of fibroblasts to identify possible promising pharmacological approaches to prevent scar formation and contractures. Methods The three-dimensional culture model was made from rat keratinocytesseeded on a collagen gel in which dermal fibroblastshad been embedded. Results Among the TRP channel inhibitors tested, the TRPV2inhibitors SKF96365 and tranilastattenuated most potently keratinocyte-dependent and — independent collagen gel contraction due to TGF-β signaling as well as TGF-β1 release from keratinocytesand α-smooth muscle actin production in myofibroblasts. Besides the low amounts detected in normal dermis, TRPV2mRNA and protein levels were increased after fibroblasts were embedded in the gel. TRPV2was also expressed in the epidermis and keratinocytelayers of the model. Both inhibitors and TRPV2siRNA attenuated the intracellular increase of Ca 2+ induced by the TRPVagonist 2-aminoethoxydiphenyl borate in TGF-β1-pretreated fibroblasts. Conclusion This is the first study to show that compounds targeting TRPV2channels ameliorate wound contraction through the inhibition of TGF-β1 release and the differentiation of dermal fibroblastsin a culture model.