Abstract
Granulation tissue formation during skin wound healing requires the migration and proliferation of dermal fibroblasts in the wound site, where a subsequent remodeling of extracellular matrices (ECM) occurs. An abnormality of ECM remodeling within the healing wound leads to fibrosis and a contracted scar. To evaluate whether acteoside, a phenylethanoid glycoside isolated from the leaves of Rehmannia glutinosa LIBOSCH., exhibits wound-healing actions, we examined the effect of acteoside on the expression of matrix metalloproteinases (MMPs) in normal human dermal fibroblasts (NHDF). Acteoside dose- and time-dependently augmented the activation of the precursor of MMP-2 (proMMP-2/progelatinase A) in untreated- and interleukin-1β-treated NHDF, while the alteration of the MMP-2 gene expression was negligible. The acteoside-induced proMMP-2 activation was associated with the augmented membrane-type 1 MMP (MT1-MMP) expression in the NHDF. In addition, the proMMP-2 activation was enhanced by two aglycones in acteoside: caffeic acid and 3,4-dihydroxyphenylethanol, which consist of catechol. However, there was no change in the proMMP-2 activation in other catechol derivatives: homovanillyl alcohol- and homovanillic acid-treated NHDF, indicating that catechols in acteoside were requisite for the regulation of the MMP activation and expression in NHDF. Furthermore, the proMMP-2 activation by acteoside was selectively inhibited by LY294002, a potent phosphatidylinositol-3-kinase (PI3K) inhibitor. These results provide novel evidence that acteoside augments proMMP-2 activation along with an increase in MT1-MMP expression through a PI3K signal pathway in NHDF. Thus, acteoside is likely to be an attractive candidate that facilitates ECM remodeling in the skin wound repair process.
