BMP/WNT-Dependent Mechanisms of Junctional Epithelium Turnover.

This article investigates the role of epithelial-to-mesenchymal transition (EMT) in the turnover and homeostasis of the junctional epithelium (JE), a tissue critical for attachment to the tooth surface and defense against periodontal disease. Using a ligature-induced periodontitis model and genetic inactivation of the bone morphogenetic protein type I receptor (BMPR1a) in mice, the study demonstrates that EMT is involved in normal JE cell migration and repair, with BMP signaling acting to regulate EMT-related pathways including Wnt/β-catenin, transforming growth factor–β, and Notch. Loss of BMP signaling leads to enhanced EMT, increased expression of matrix metalloproteinases and mesenchymal markers, and disruption of hemidesmosomal proteins essential for JE attachment. These findings suggest that EMT, modulated by BMP and Wnt signaling, is integral to JE turnover and may influence periodontal tissue integrity.