Characterisation of Epithelial-Mesenchymal Transition (EMT) in Oral Keratinocytes

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INTRODUCTION: The oral cavity is heavily colonised by a diverse microflora. Complex bacterial biofilms develop on the dental hard tissues (teeth) and in particular on the root surface in the gingival crevice where they become intimately associated with the crevicular epithelium. This epithelium, exhibits properties in common with other bodily sites and plays a key role in protecting the underlying host tissues from bacterial invasion. Indeed this epithelium can orchestrate the local inflammatory response and releases defence molecules which help maintain its integrity. A potential novel process that occurs in the oral epithelia is that of epithelial-mesenchymal transition (EMT) which results in the conversion of epithelial cells to a mesenchymal phenotype. While EMT is essential in tissue formation and repair its dysregulation during disease can result in the development of prolonged and chronic cytokine release perpetuating bacterial tissue invasion and resulting in a chronic inflammatory lesion.HYPOTHESIS: Key oral bacteria disrupt the epithelial barrier via EMT resulting in ulceration and a non-resolving chronic inflammatory lesion.The project will involve the development of an EMT model system (2D & 3D) using immortal and primary human cells. EMT regulation will subsequently be assessed using molecular and cellular assays including gene & protein expression analysis, cell morphological & histological characterisation, epithelial barrier and bacterial invasion studies which involve relevant interacting immune system cells, e.g. neutrophils. EMT intracellular signalling pathways (e.g. NF-kB, SMAD) will also be dissected in model systems using pharmaceutical modulators. KEY REFERENCES: 1. Milward. MR, Chapple ILC, Wright HJ, Millard JL, Matthews JB, Cooper PR. Differential Activation of NF-kB and gene expression in oral epithelial cells by periodontal pathogens. Clin Exp Immunol. 2007 May;148 (2): 307-324 2. Prime SS, Nixon SV, Crane IJ. The behaviour of human oral squamous cell carcinoma in cell culture. J Pathol 1990; 160 (3): 259-269 3. Khan E, Shelton RM, Cooper PR, Hamburger J, Landini G. Architectural characterization of organotypic cultures of H400 and primary rat keratinocytes. J Biomed Mater Res A. 2012 Jun 26.4. Abdulkareem; Milward; Cooper; Shelton; Landini. Periodontal pathogens promote EMT in oral squamous carcinoma cells in vitro, accepted for publication in Cell Adhesion & Migration 2017.