Gene-expression profiles of epithelial cells treated with EMD in vitro: analysis using complementary DNA arrays I. Kapferer 1 , S. Schmidt 2 , R. Gstir 3 , G. Durstberger 4 , L. A. Huber 3 , I. Vietor 3 1 Department of Operative Dentistry, Dental School, Innsbruck Medical University, Innsbruck, Austria, 2 Department of Internal Medicine, Division of Hematology and Oncology, Innsbruck Medical University, Innsbruck, Austria, 3 Division of Cell Biology, Biocenter, Innsbruck Medical University, Innsbruck, Austria and 4 Department of Periodontology, Bernhard-Gottlieb Dental School, Vienna Medical University, Vienna, Austria Clinical and histological investigations have demonstrated that intrasurgical application of porcine EMD results in the regeneration of various periodontal tissues, such as alveolar bone, acellular cementum and new periodontal liga- ment (1–4). Wound healing following conventional periodontal therapy fre- quently does not result in regeneration but rather in the down-growth of a long junctional epithelium (1). When applied to denuded root surfaces, EMD precipitates to form an extra- cellular matrix layer, potentially sup- porting interactions with cells in adjacent tissues (4). EMD is produced by HertwigÕs epithelial sheath during dentinogenesis and is commercially available from acid extracts of enamel buds of 6-mo-old pigs. The composi- tion is rather heterogeneous and includes concentrated amelogenin components, degradation products and specific splicing products, along with Kapferer I, Schmidt S, Gstir R, Durstberger G, Huber LA, Vietor I. Gene-expression profiles of epithelial cells treated with EMD in vitro: analysis using complementary DNA arrays. J Periodont Res 2011; 46: 118–125. Ó 2010 John Wiley & Sons A/S Background and Objective: During surgical periodontal treatment, EMD is topi- cally applied in order to facilitate regeneration of the periodontal ligament, acel- lular cementum and alveolar bone. Suppresion of epithelial down-growth is essential for successful periodontal regeneration; however, the underlying mech- anisms of how EMD influences epithelial wound healing are poorly understood. In the present study, the effects of EMD on gene-expression profiling in an epithelial cell line (HSC-2) model were investigated. Material and Methods: Gene-expression modifications, determined using a com- parative genome-wide expression-profiling strategy, were independently validated by quantitative real-time RT-PCR. Additionally, cell cycle, cell growth and in vitro wound-healing assays were conducted. Results: A set of 43 EMD-regulated genes was defined, which may be responsible for the reduced epithelial down-growth upon EMD application. Gene ontology analysis revealed genes that could be attributed to pathways of locomotion, developmental processes and associated processes such as regulation of cell size and cell growth. Additionally, eight regulated genes have previously been reported to take part in the process of epithelial-to-mesenchymal transition. Several inde- pendent experimental assays revealed significant inhibition of cell migration, growth and cell cycle by EMD. Conclusion: The set of EMD-regulated genes identified in this study offers the opportunity to clarify mechanisms underlying the effects of EMD on epithelial cells. Reduced epithelial repopulation of the dental root upon periodontal surgery may be the consequence of reduced migration and cell growth, as well as epithelial- to-mesenchymal transition. Ines Kapferer, DMD, MSc, Reichenauerstraße 46, 6020 Innsbruck, Austria Tel: 0043 512 504 27221 Fax: 0043 512 504 27184 e-mail: ines.kapferer@gmx.net Key words: enamel proteins; epithelium; micro- array; wound healing Accepted for publication July 19, 2010 J Periodont Res 2011; 46: 118–125 All rights reserved Ó 2010 John Wiley & Sons A/S JOURNAL OF PERIODONTAL RESEARCH doi:10.1111/j.1600-0765.2010.01321.x