Gingival Keratinocytes Contribute to Superior Wound Healing

Objectives: The gingival tissue, compared to skin, is renowned for its ability to heal both at an accelerated rate and with reduced scarring. In this project we aim to explore the differing healing efficiencies of gingival versus cutaneous keratinocytes, alongside investigating their differential gene expression patterns.

Methods: To achieve these aims we developed 3D organotypic culture models of primary cells to recreate human gingiva and skin. Wounding these models has enabled us to visualise re-epithelialisation and analyse both the migration and proliferation of keratinocytes to close the wound gap in a 3D environment. Concurrently, we identified and validated genes that are differentially expressed between primary gingival versus cutaneous keratinocytes using qPCR and protein quantification. We then utilised siRNA to knockdown a selection of these genes and study the functional effects on viability, migration and proliferation.

Results: Our 3D cultures of the gingiva and skin show similar stratification and differentiation, via immunofluorescence, to their in vivo tissue counterparts. Upon wounding, gingival models display a markedly higher efficiency in healing, closing the wound gap within 24 hours, whereas the skin models are still migrating after 72 hours. We also show that a number of genes, including PITX1 and PITX2, are expressed at a significantly higher level in gingival versus skin keratinocytes, both prior to and post wounding. We are currently investigating the effect that siRNA knockdown of these genes has on the healing efficiency of the cells.

Conclusions: We show that superior wound healing of the gingiva found in vivo is replicable in vitro, highlighting the importance of keratinocytes in the healing process. Furthermore, comparing gene expression between gingival versus cutaneous keratinocytes indicates intrinsic differences between the cells. It is hoped that with further research it will be possible to apply this knowledge to improve healing efficiency of other tissues.