Modulation of collagen and keratin synthesis in co-cultures of fibroblasts and keratinocytes on hyaluronan-coated polysulfone membranes

Human epidermal keratinocytes and dermal fibroblasts were co-cultured on polysulfone (PSU) membranes, previously coated or not with hyaluronan (HA), and compared to monocultured keratinocytes and fibroblasts. The purpose was to define the interplay between both cell types and how it is influenced. The co-cultures reduced types I and III collagen levels, indicating that keratinocytes exerted an inhibition on matrix synthesis by fibroblasts. On the other hand, the amounts of keratins 17 and 10 were increased, suggesting that fibroblasts stimulate the production of keratins by keratinocytes. In contrast with naked PSU membranes, HA coatings increased types I and III collagens mRNA (messenger ribonucleic acid) levels, suggesting that HA counteracts the inhibition produced by keratinocytes. Changes were also observed in the expression of metalloproteinases (MMPs) on HA-coated PSU membranes. The presence of keratinocytes increased MMP1 and MMP3 synthesis by fibroblasts whereas HA exerted an inhibitory effect on MMP2 expression that depended on the culture conditions. The TGF-beta 3 mRNA levels were very high in co-cultures on PSU, whereas TGF-beta 1 mRNA was rather low; this was amplified on HA-coated membranes. These data provide a deeper insight into the intercellular interactions between dermal fibroblasts and keratinocytes, and their modulation by the culture support of these cells.