RESUMO
Wounds within the oral mucosa, similarly to fetal wounds, exhibit rapid healing with reduced scarring. We hypothesized that a progenitor population resident within the oral mucosal lamina propria (OMLP) contributes to this preferential healing. Progenitor cells (PC) were reliably isolated from the OMLP by differential adhesion to fibronectin. Isolated colonies originating from a single cell demonstrated a rapid initial phase of proliferation, completing in excess of 50 population doublings (PDs) before entering cellular senescence. These data were supported by the expression of active telomerase within both developing colonies and expanded clones as assessed by immunocytochemistry (ICC) and the quantitative telomeric repeat amplification protocol. FACS analysis confirmed expression of the stem cell markers CD44, CD90, CD105, and CD166, but negative expression of CD34 and CD45 ruling out a hematopoietic or fibrocyte origin for these progenitors. A neural crest origin was confirmed by increased colony-forming efficiency (CFE) in the presence of Jagged 1 and the expression of a number of neural crest markers within the developing colonies by ICC and serially passaged clones by Western blotting. The multipotency of this novel PC population was demonstrated by differentiation of the cells down both mesenchymal (chondrogenic, osteoblastic, and adipogenic) and neuronal (neuron and Schwann-like cells) cell lineages. This article reports for the first time, the isolation and characterization of a novel, clonally derived PC population resident within the OMLP. The attributes of this adult stem cell (ASC) population and its accessibility lends itself to future therapeutic applications.
