Methylation pattern of IFN-γ and IL-10 genes in periodontal tissues

DNA methylation is characterized by the addition of methyl groups in cytosines within CpG islands. Unmethylated CpCs are related to transcriptionally active structure, whereas methylated CpG recruits methyl-binding proteins that promote chromatin compaction. DNA methylation can influence the expression of cytokines and affect the development of periodontal disease. Objectives: The purpose of the present study was to evaluate the methylation status of the interferon gamma (IFN-gamma) and interleukin-10 (IL-10) genes in periodontal tissues. Design: Methylation-specific polymerase chain reaction (MSP) and DNA sequencing analysis were used to verify the DNA methylation status of the IFN-gamma and IL-10 genes, respectively, in samples from subjects without periodontitis and individuals with chronic periodontitis. Histological sections stained by hematoxylin-eosin were used for histopathological evaluation of samples. Results: The methylation status of the IFN-y and IL-10 genes was similar among the groups. Most of the samples were positive for IFN-gamma methylation. Only 11% of the periodontitis group showed unmethylated DNA. Considering the IL-10 gene, no unmethylated sample was observed. The profile of total or partial methylation was detected in CpGs evaluated. Conclusions: The results showed evidence that methylation of IFN-y and IL-10 genes is a usual feature on periodontal tissues. Further studies are needed to determine the functional relevance of these alterations. (C) 2011 Elsevier GmbH. All rights reserved.