Gene Profile in Periodontal Ligament Clones with Enamel Matrix Proteins

Background: Enamel matrix proteins (EMP) mostly composed of amelogenins, have been proven to enhance proliferation, total protein synthesis and mineral nodule formation by PDL cells in-vitro. PDL cell population is heterogeneous and composed of fibroblastic and mineralized tissue forming lineages. Objectives: The present study is aimed at providing gene expression profiles derived from EMP treated cultured human clones. Materials and methods: Human PDL cells were explanted from freshly extracted tooth roots. Clones were divided to fibroblastic (Fb) clones and mineralized tissue-forming (MTF) on the basis of their capacity to express alkaline phosphatase and to form mineralized tissue in vitro. Clones were immortalized using the recombinant retroviral vector from Papilloma virus. Cultures of immortalized clones were grown for 7 days, with and without the addition of EMP to the medium and were assessed for expression profiling of different genes. Following RNA extraction from cells, expression profiling was performed via hybridization with DNA microarray. Results: The main functional gene groups activated in the MTF clones were the nucleic acid metabolism, protein metabolism and signal transduction. While, in the Fb clones, were cell adhesion, nucleic acid metabolism, and signal transduction. Conclusions: EMP significantly influenced PDL cell function, by up- or down-regulating several gene expressions, with a general effect on enhanced cell functional metabolism. EMP affected differently both clones.