TGF-β1-induced HSP47 regulates extracellular matrix accumulation via Smad2/3 signaling pathways in nasal fibroblasts

Abstract

HSP47 is required for the production of collagen and serves an important role in tissue remodeling, a pathophysiologic mechanism of chronic rhinosinusitis (CRS). We investigated the relationship between HSP47 expression and tissue remodeling in CRS. We also determined the underlying molecular mechanisms of TGF-β1-induced HSP47 and extracellular matrix (ECM) production in nasal fibroblasts. HSP47, α-SMA, fibronectin, and collagen type I expression levels were measured using real-time PCR, western blotting, and immunofluorescence staining. Fibroblast migration was analyzed using scratch and transwell migration assays. Contractile activity was measured with a collagen gel contraction assay. HSP47 is increased in patients with CRS without nasal polyps. TGF-β1 induced HSP47 expression in nasal fibroblasts. Myofibroblast differentiation and ECM production, which are induced by TGF-β1, were inhibited by siHSP47. We also confirmed that the Smad2/3 signaling pathway is involved in TGF-β1-induced HSP47 expression in nasal fibroblasts. In a functional assay, TGF-β1-enhanced migration and contraction ability were inhibited by HSP47 knockout. Glucocorticoid reversed the stimulatory effects of TGF-β1 on HSP47 expression and ECM production in nasal fibroblasts and ex vivo organ cultures. HSP47 expression is involved in TGF-β1-induced myofibroblast differentiation and ECM production through the Smad2/3 signaling pathway, which might contribute to tissue remodeling in chronic rhinosinusitis.