| Summary: | It is widely observed that dermal wound healing results in the re-establishment of skin continuity through the formation of a scar. In comparison oral wounds heal more rapidly, with less visible scarring. The diverse nature of sub-epithelial fibroblasts has targeted them as mediators for such a distinction in phenotype. Fibroblasts and their differentiated form, the myofibroblast (characterised by the expression of α-SMA), are chief synthesisers of the ECM during wound healing. Myofibroblasts in particular play an important role in wound contracture, ECM synthesis and remodelling during normal wound healing and scar production; but are also observed in fibrosis and pathological scarring. The most potent mediator of this phenotype in the cytokine TGFβ1, which is abundantly present throughout wound healing. Here we used organotypic co-cultures and mono-cultures to assess the differences in phenotype and the relative contribution of topographically distinct fibroblasts within them. There is currently little data on the responsiveness of oral buccal mucosal and skin fibroblasts to TGFβ1, particularly when keratinocytes are present in a 3D environment. Here, for the first time, we used heterotypic organotypic co-cultures containing skin and oral buccal mucosal fibroblasts and added TGFβ1 under both resting and tethered conditions. We monitored the changes in response of these fibroblasts with and without the presence of keratinocytes, and subsequently assessed changes in phenotype upon substitution of the dermal fibroblasts with those from the reduced scarring oral buccal mucosa. Under resting conditions oral fibroblast seeded organotypics showed a lower constitutive myofibroblast expression, and were unresponsive to TGFβ1 mediated α- SMA expression, regardless of substrate compliance. These fibroblasts were found to significantly promote epithelial maturation under resting conditions, and express higher levels of active MMP-9 (and enzyme involved with keratinocyte migration) upon treatment with TGFβ1, when compared to dermal fibroblast seeded counterparts. When oral fibroblasts were introduced into a dermal organotypic co-culture environment, we observed a preferential change α-SMA phenotype, offering the potential for use of these cells in an area distinct from there origin to a favourable effect.
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