The Junctional Epithelium Is Maintained by a Stem Cell Population.
The most fundamental function of an epithelial tissue is to act as a barrier, regulating interactions between the external environment and the body. This barrier function typically requires a contiguous cell layer but since teeth penetrate the oral epithelium, a modified barrier has evolved, called the junctional epithelium (JE). In health, the JE attaches to the tooth, sealing the inside of the body against oral micro-organisms. Breakdown of the JE barrier results in periodontal ligament (PDL) disintegration, alveolar bone resorption, and ultimately tooth loss. Using lineage tracing and DNA pulse-chase analyses, we identified an anatomical location in the JE that supported both fast- and slow-cycling Wnt-responsive stem cells that contributed to self-renewal of the tissue. Stem cells produced daughter cells with an extraordinarily high rate of turnover that maintained JE integrity for 1.4 y in mice. Blocking cell proliferation via a chemotherapeutic agent 5-fluorouracil (5-Fu) eliminated fast-cycling stem cells, which caused JE degeneration, PDL destruction, and bone resorption. Upon removal of 5-Fu, slow-cycling stem cells regenerated both the structure and barrier function of the JE. Taken together, our studies identified a stem cell population in the JE and have potential clinical implications for prevention and treatment of periodontitis.
['Yuan|X|X|0000-0002-8063-9431', 'Chen|J|J|', 'Grauer|J A|JA|', 'Xu|Q|Q|', 'Van Brunt|L A|LA|', 'Helms|J A|JA|0000-0002-0463-396X']
D000818:Animals D004846:Epithelial Attachment D004848:Epithelium D005881:Gingiva D051379:Mice D010513:Periodontal Ligament D013234:Stem Cells D014070:Tooth
periodontitis cell proliferation Wnt signaling pathway epithelial cells gingiva stem cell research