Overexpression of Transforming Growth Factor α in Psoriatic Epidermis

TLDR

Transforming growth factor α (TGF‑α) is produced by and required for the growth of epithelial cells and is angiogenic in vivo. The study aimed to assess whether TGF‑α expression differs between normal and psoriatic epidermis. The authors quantified TGF‑α mRNA and protein in epidermal biopsies from normal and psoriatic skin. Lesional psoriatic epidermis shows markedly higher TGF‑α mRNA and protein levels compared to normal skin, while TGF‑β1 levels remain unchanged, suggesting hyperplasia is driven by increased TGF‑α rather than reduced TGF‑β1.

Abstract

Transforming growth factor α (TGF-α) is produced by and required for the growth of epithelial cells and is angiogenic in vivo. Since epidermal hyperplasia and angiogenesis are hallmarks of psoriasis, TGF-α gene expression was analyzed in epidermal biopsies of normal and psoriatic skin. TGF-α messenger RNA and protein are much more abundant in lesional psoriatic epidermis than in normal-appearing skin of psoriatic patients or in normal epidermis. In contrast, messenger RNA levels of transforming growth factor β1 (TGF-β1), which inhibits epithelial cell growth, are not significantly different in normal, uninvolved, and lesional psoriatic epidermis. Thus, psoriatic epidermal hyperplasia may involve increased expression of a keratinocyte mitogen (TGF-α) rather than deficient expression of a growth inhibitor (TGF-β1).