Comparative studies on the secretion and activation of MMPs in two reconstructed XXXX skin models using HaCaT- and HaCaT-ras-transfected cell lines.

@entity1 @entity3334 @entity1476 @entity5 @entity1549 @entity1495
Matrix metalloproteinases play an important role in tissue regeneration, wound healing and @entity5 invasion. Our previous studies have shown a higher motility of HaCaT-ras-transfected cells compared with HaCaT or normal @entity1 keratinocytes (NHK) in correlation with a higher secretion of @entity1476 (72 kDa) or @entity1495 (92 kDa), according to the medium used for cell cultures. Presently, the expression and activity of MMPs were investigated in two reconstructed skin models, using a dead de-epidermized dermis (DED) or a dermal substitute including living fibroblasts. In all experiments, @entity1495 was essentially secreted by NHK and to a greater extent by HaCaT cells. Its active form (86 kDa) was only detected in both reconstructed skin models according to keratinocyte differentiation. @entity1476 was mainly secreted by living fibroblasts included in the dermal substitute skin model. In this case, its activation was up-regulated when HaCaT cell lines were seeded onto the dermal substitute according to their culture at air/liquid interface as shown for @entity1495 . The collagenase @entity3334 and stromelysin-1 ( @entity1549 ), susceptible to activate pro- @entity1476 and -9, respectively, were detected in their inactive form by ELISA. @entity3334 was expressed in both models but @entity1549 required the presence of living fibroblasts. Their activities were not detected using specific fluorogenic substrates. In the skin equivalent model using HaCaT, the extensive secretion and activation of @entity1476 and @entity1495 could explain the defect observed in basal membrane reconstruction, suggesting a direct interaction of HaCaT with fibroblasts.
