Gene expression profiling of cells involved in periodontal regeneration

Understanding the molecular mechanisms involved in periodontal regeneration is important for the development of more predictable clinical techniques. This study aimed to identify these mechanisms by comparing the gene expression profiles of cells derived from regenerating defects with patient-matched periodontal ligament cells. Gene profiling was carried out via Affymetrix U133A arrays containing probes for 22,000 genes. Robust differences in gene expression were obtained by identifying genes that consistently changed by a minimum of 2-fold. Analysis of molecular function as designated by gene ontology (GO) identified differentially regulated mechanisms including protein metabolism, tyrosine kinase activity, and skeletal development. The differentially expressed genes could be broadly divided into the categories of protein biosynthesis and turnover, structural constituents of the cytoskeleton and extracellular matrix, and signal transduction. The differential expression of 4 genes (EGR-1, elastin, osteoprotegerin, and IGFBP3) was confirmed via real-time polymerase chain reaction (PCR). Further, the expression of another 2 differentially expressed transcripts, decorin and biglycan, was immunohistochemically confirmed in a periodontal wound healing model and the protein expression was consistent with the pattern of gene expression. This study gives insight into the molecular processes involved in periodontal regeneration and identifies cell markers that are characteristic of regenerating periodontal tissues.