Transforming growth factor β increases steady state levels of type I procollagen and fibronectin messenger RNAs posttranscriptionally in cultured human dermal fibroblasts

Abstract

Transforming growth factor-β (TGFβ), when injected subcutaneously into newborn mice, induces a rapid fibrotic response, stimulates chemotaxis, and elevates the rates of biosynthesis of collagen and fibronectin by fibroblasts in vitro. We explored the molecular mechanisms of TGFβ-mediated stimulation of collagen and fibronectin synthesis in cultured human foreskin fibroblasts. TGFβ preferentially stimulated the synthesis of fibronectin and type I procollagen chains 3-5-fold as shown by polypeptide analysis. Concomitant elevation in the steady state levels of messenger RNAs (mRNAs) coding for type I procollagen and fibronectin also occurred but without a net increase in the rate of transcription of either of these genes. The preferential stabilization of mRNAs specifying type I procollagen and fibronectin provides a partial explanation for the mechanisms by which TGFβ enhances the synthesis of type I procollagen and fibronectin in mesenchymal cells.