Epidermal growth factor affects the synthesis and degradation of type I collagen in cultured human dermal fibroblasts

EGF and type I collagen are known to play important roles in wound healing. In the present study, we demonstrated that EGF down-regulates the expression of type I procollagen protein as well as α2(I) collagen mRNA in cultured human dermal fibroblasts. EGF induced the degradation of type I procollagen protein in conditioned medium through the up-regulation of MMP-1 expression. EGF down-regulated α2(I) mRNA expression partially at the post-transcriptional level by reducing the mRNA stability. In contrast, EGF up-regulated MMP-1 mRNA expression mostly at the transcriptional level, in that it had a stimulatory effect on MMP-1 promoter activity, but no effect on MMP-1 mRNA stability. The MEK/ERK signaling pathway was shown to be involved in EGF-mediated type I collagen and MMP-1 expression.