Differential regulation of skin fibroblasts for their TGF-β1-dependent wound healing activities by biomimetic nanofibers

Abstract

With the increase in interest for using electrospun nanofibers for skin tissue formation, it has become essential to establish the correlation between nanofiber configurations and skin cell responses. In this regard, the present study was aimed at understanding how nanofiber matrices, especially their chemical composition, regulate the phenotype of dermal fibroblasts in a transforming growth factor (TGF)-β1 rich milieu close to the native wound-healing microenvironment. Cultures of human dermal fibroblasts on fibrinogen- and collagen-containing electrospun nanofiber matrices revealed that with the presence of exogenous TGF-β1 the fibroblasts on fibrinogen matrices exhibited a differentiation phenotype, characterized by lower proliferation, faster migration and higher expression of α-smooth muscle actin (α-SMA), in contrast to the proliferation phenotype on collagen matrices. Such distinct cellular responses are a result of the differential activation of TGF-β1/Smad signaling in fibroblasts on different nanofiber matrices, with marked elevation of TGF-β1 receptor I and Smad2/3 phosphorylation on the fibrinogen fibers. Blockade of integrin α_Vβ₃ with an inhibitor (Cilengitide) showed a decreased migration and expression of α-SMA in fibroblasts along with a reduced Smad3 phosphorylation, confirming the involvement of integrin α_Vβ₃ in TGF-β1-induced fibroblast differentiation on the fibrinogen-containing nanofibers. These findings demonstrate the regulatory effects of nanofiber composition on the TGF-β1-dependent wound-healing activities of skin fibroblasts through the integrin-mediated signaling pathway. Meanwhile, these results also point out the importance of recreating the wound microenvironment for in vitro studies on materials–cell interactions.