Platelet-derived growth factor isoforms PDGF-AA, -AB and -BB exert specific effects on collagen gene expression and mitotic activity of cultured human wound fibroblasts.

This study was designed to clarify the action of three different isoforms of PDGF (PDGF-AA, PDGF-AB and PDGF-BB) on the proliferation rate and collagen synthesis of fibroblasts cultured from normal human wounds. PDGF-AA and PDGF-BB down-regulated both the steady-state levels of pro alpha 1 (I) and pro alpha 1 (III) collagen chain mRNAs and the production of collagen, both in a dose-dependent manner. Interestingly, low concentrations (1 ng/ml) of PDGF-AB up-regulated the expression of type I and III procollagen mRNAs by cultured wound fibroblasts, while under high concentrations (30 ng/ml) of PDGF-AB this effect changed to the opposite. The proliferation rate of wound fibroblasts was stimulated by PDGF-BB which elicited a dose-dependent (1-30 ng/ml) stimulation of cell proliferation, whereas PDGF-AB and -AA were less effective in this respect.