Increased expression of integrin α2 and abnormal response to TGF‐β1 in hereditary gingival fibromatosis

Abstract

To investigate the possible correlation between integrin alpha1, alpha2, and beta1 expression and excessive collagen synthesis in fibroblasts from 3 unrelated Chinese families with hereditary gingival fibromatosis (HGF). Gingival fibroblasts from three Chinese HGF patients and three healthy subjects were included. The expression of alpha1, alpha2, and beta1 integrin subunits was examined by immunohistochemistry, quantitative PCR, and flow cytometry. We also investigated the effects of transforming growth factor-beta1 (TGF-beta1) on the expression of these integrin subunits. Our results demonstrate that the expression of alpha2 was significantly higher in HGF fibroblasts compared with control fibroblasts (P < 0.01). No significant differences in the expression of alpha1 and beta1 were detected. Furthermore, TGF-beta1 promoted the expression of alpha1 and alpha2 in fibroblasts from both HGF patients and controls. However, it had a larger effect on the expression of alpha2 in HGF fibroblasts than in control cells. In contrast, alpha1 expression was stimulated more in control fibroblasts. The increased expression of integrin alpha2 and the increased response to TGF-beta1 of HGF fibroblasts may be related to the excessive collagen deposition in HGF patients.