Transforming Growth Factor-??, Smad, and Collagen Expression Patterns in Fetal and Adult Keratinocytes

The study investigated the expression patterns of Transforming Growth Factor-β (TGF-β) isoforms, receptors, Smad signaling molecules, and collagen type I in keratinocytes from fetal (n = 6), newborn (n = 4), and adult (n = 4) Sprague-Dawley rats. Results showed an increase in TGF-β isoform expression, particularly TGF-β1, from fetal to adult stages, with a 25-fold higher expression in fetal keratinocytes. TGF-β receptor 1 (RI) and receptor 2 (RII) expressions also increased with age, as did Smad4, while Smad7 remained unchanged. Collagen type I expression saw a dramatic over 100-fold increase from fetal to adult stages. These findings suggest an upregulation of the TGF-β system and collagen production with age in keratinocytes, which may contribute to the scarring observed in postnatal wounds. The study highlights the need for further research into the role of keratinocyte collagen synthesis in wound repair and the differences in TGF-β3 expression between fetal and postnatal keratinocytes and fibroblasts.