Morphogenesis of dermal–epidermal junction in a model of reconstructed skin: beneficial effects of vitamin C

In skin, cohesion between the dermis and the epidermis is ensured by the dermal-epidermal junction which is also required for control of epidermal growth and differentiation. Here we showed that addition of vitamin C optimized the formation of the dermal-epidermal junction in an in vitro human reconstructed skin model leading to a structure closer to that of normal human skin. Compared with controls, vitamin C treatment led to a better organization of basal keratinocytes, an increase in fibroblast number and a faster formation of the dermal-epidermal junction. Vitamin C also accelerated deposition of several basement membrane proteins, like type IV and VII collagens, nidogen, laminin 10/11, procollagens I and III, tenascin C and fibrillin-1 at the dermal-epidermal junction. The mechanism of action of vitamin C was investigated by quantitative polymerase chain reaction in fibroblasts and keratinocytes respectively. Vitamin C effects passed in part through an increase in col I alpha1, col III alpha1 and fibrillin-1 mRNA levels. Effects on the other markers appeared to happen at the translational and/or post-translational level, as illustrated for tenascin C, col IV alpha2 and col VII alpha1 mRNA levels which were reduced by vitamin C in both cell types.