Developmental initiation of elastin gene expression by human fetal skin fibroblasts

Elastin synthesis is initiated in many organs during the latter part of fetal development. By birth, accumulation of elastin in elastic fibers accounts in large part for the integrity and resilience of skin, blood vessels, and lungs. Developmental studies in several connective tissues of nonhuman vertebrates indicate that elastin synthesis is rapidly initiated during fetal life and that its expression is largely controlled by the abundance of its mRNA. Previous evidence for elastin synthesis in the developing human fetus has been derived from either histologic inference or studies of net accumulation. We now report that the developmental induction of cutaneous elastin synthesis appears to be stably reflected in cell culture. Production of elastin by human skin fibroblasts increased 7- to 14-fold between 17 and 19 weeks of gestation, reaching the levels found in neonatal skin fibroblasts. Consistent with other developmental studies, elastin synthesis was found to be under pretranslational control with relative mRNA levels increasing 6- to 15-fold by 19 weeks of gestation. Under the same circumstances, collagen expression and total protein synthesis were relatively constant among all strains examined. Human skin fibroblasts may thus be a useful system for examining developmentally regulated elastin gene expression.