Effect of sulfated GAGs on the expression and activation of MMP-2 and MMP-9 in corneal and dermal explant cultures

It has been shown previously that hyaluronan (HA) added to fibroblast and keratocyte cell cultures or corneal explant cultures produces an up-regulation of MMP-2 and MMP-9 expression and activation. Here, we examine the effect of sulfated GAG-s, chondroitin 4 and 6 sulfate (CS4, CS6), dermatan sulfate (DS), keratan sulfate (KS) and heparan sulfate (HS) on MMP-2 and 9 expression and activation under the same culture conditions. It appears that CS4 has only minor effects, KS inhibits MMP-2 activation and CS6, DS and HS increase MMP-2 activation in corneal explant cultures. For skin explant cultures, DS, KS and HS strongly increase MMP-9 activation, whereas KS inhibits and DS increases MMP-2 activation. All these effects can be strongly inhibited by the addition of an antibody to CD44, except CS6 and DS. Activation by these two GAGs was only slightly affected, supporting the contention that the effects of HA, CS4, KS and HS are mediated by one of the isoforms of this CD44 receptor. The physio-pathological significance of these results is discussed for cornea and skin ageing, because of the divergent evolution with in vitro ageing of the relative proportions of GAGs synthesised by these two cell types.