The Isolation of Multipotent Cells From the Oral Lamina Propria

OBJECTIVES: The oral mucosa, like foetal wounds, exhibits rapid healing with reduced scarring. We hypothesised that a progenitor population within the adult oral mucosal lamina propria [OMLP] contributes to this preferential healing.

METHODS: Potential progenitor cells [PC] were isolated from the OMLP (n=3) and colony forming efficiency determined (+/-DAPT or Jagged-1) using a differential adhesion assay. Clones were isolated, passaged and population doubling levels [PDLs] determined. Telomere lengths and telomerase activity were established. FACS was performed for CD markers. Whole, digested OMLP and PCs were analysed for neural crest [NC] and embryonic markers by PCR and immunocytochemistry [ICC]. PCs were differentiated down a chondrogenic lineage and investigated by PCR and ICC.

RESULTS: PCs (CD90, CD105, CD166 positive; CD34, CD45 negative) were reliably isolated from the OMLP. These PCs exhibited: high initial PD levels (>4PD/week), long telomeres and expressed active telomerase (an enzyme associated with an embryonic-like phenotype, a hypothesis supported by the expression of Oct 4 within digested OMLP). DAPT and Jagged-1 significantly enhanced colony formation suggesting a NC origin for these cells. ICC and PCR confirmed this, demonstrating the expression of NC markers (Slug, Snail, Twist, Sox10) within PC populations. The expression of the chondrogenic markers (type II collagen, aggrecan and Sox 9) demonstrated the ability of these PCs to differentiate down a mesenchymal lineage. Their differentiation down adipogenic, osteogenic and neural lineages is currently under investigation.

CONCLUSION: This is the first report of both isolation of telomerase positive PCs from the OMLP and expression of the embryonic marker Oct4 within the OMLP. This work demonstrates the persistence of a readily accessible, neural crest-derived embryonic PC population in the OMLP. The potential of this multipotent cell population for applications in dentistry and tissue engineering is currently being explored.

Research funded by The Osteology Foundation (06/024) and The Wellcome Trust.