Transforming Growth Factors β1, β2, and β3 and Their Receptors Are Differentially Regulated during Normal and Impaired Wound Healing

Abstract

A series of studies has shown that application of transforming growth factor beta (TGF-beta) to a wound has a beneficial effect, especially in animals with wound healing disorders. In this study we have investigated the regulation of TGF-beta1, beta2, and beta3 and their receptors during the repair process. We found a large induction of all three TGF-beta isoforms and also of TGF-beta types I and II receptors, although the time course of induction and the absolute expression levels were different for these genes. Furthermore, each TGF-beta isoform had distinct sites of expression in the wound. Systemic treatment with glucocorticoids significantly altered the expression levels of TGF-betas and TGF-beta receptors. Whereas expression of TGF-beta1, TGF-beta2, and TGF-beta type II receptor was suppressed by glucocorticoids in normal and wounded skin, expression of TGF-beta3 and TGF-beta receptor type I mRNA was stimulated. These findings provide an explanation for the beneficial effect of exogenous TGF-beta in the treatment of impaired wound healing in glucocorticoid-treated animals. Furthermore, they suggest that a disturbed balance between the levels of the three TGF- beta isoforms and their receptors might underlie the wound healing defect seen in glucocorticoid-treated animals.