DNA Microarray Analysis of Healthy and Diseased Periodontal Tissues

Objectives: The onset and progression of periodontitis is determined by a biofilm induced inflammatory response. Although the expression of individual candidate genes has been studied extensively in vitro, there is limited information on the complex interplay of inflammatory genes in vivo. A comprehensive analysis of genes involved in the inflammatory process, may help elucidate regulatory pathways in periodontitis. The aim of the study was to identify over- or underexpressed inflammatory genes in the gingival tissue of patients with severe chronic periodontitis. Material & Methods: Gingival biopsies from 12 patients with severe chronic periodontitis and 11 healthy controls were obtained under local anaesthesia. RNA of an immortalized human keratinocyte line (HaCaT) was used as the internal standard. Tissue and cell culture specimen were kept in a RNA stabilizing agent until RNA-isolation. The quality and concentration of the RNA was analyzed by an Agilent 2100 Bioanalyzer (Agilent Technologies Inc., USA). The 260/280 Quotient was 1.9 – 2.1 and the concentration between 0.5 – 1.5 µg/µl. Total RNA was subjected to gene expression profiling using a commercially available microarray system (MWG Biotech, Germany). The 5% most and the 5% least expressed genes were identified and their possible interaction analyzed by the PathwayAssist software (Stratagene Inc, USA). Post-hoc confirmation was done by real-time-PCR of selected samples of the overexpressed genes. Results: Out of the 136 genes analyzed, IL-12, CSPG-2, MMP-1, DSCR-1, CXCL-3, BIRC-1, CD38, RGS-1, and C-FOS were upregulated and RIPK-2, C3, PTGS-2, CXCL-8, EDN-1, SERPINB-2, MMP-14, and IRF-7 were downregulated. Analysis of these data indicated that a DSCR-1 dependent regulatory process might be involved in periodontitis. Conclusion: The data indicates that the Down Critical Region Protein-1 (DSCR-1) may play a crucial role in the regulation of periodontal inflammation. This study was supported by the Federal German Ministry of Education and Research (No. 01KS9604/0).