Methylation Status of Promoter Region of Tumor Necrosis Factor Alpha Gene in Subjects with Healthy Gingiva and Chronic Periodontitis - A Pilot Study.

Abstract

Periodontitis is a multi-factorial disease with bacterial origin. The progression is influenced by systemic disease, smoking, genetic factors. In the recent past epigenetic influences have been indentified on the candidate genes which code for proteins that play a role in the pathogenesis of the periodontal disease. Epigenetic mechanisms involve DNA methylation and histone modification. Till date, there is no existing data associating methylation status of the promoter region (-239, -245) of the TNF alpha gene and chronic periodontitis. The objective of this study was to compare the methylation status of CpG islands in the promoter region of TNF alpha (-239, -245) gene in the peripheral blood among subjects with healthy gingiva and chronic periodontitis. A case control study design involving 50 subjects (25 healthy and 25 subjects with chronic periodontitis) was performed. DNA was isolated from peripheral blood of all the subjects and bisulfate modification with methylation specific polymerase chain reaction (MS-PCR) was performed. The methylation status of the selected region of the Tumor necrosis factor alpha gene for both the test and control groups was evaluated and assessed. The mean Ct value for the methylation of control group was 24.36 and in the periodontitis group the mean Ct value was found to be 28.09. The higher the Ct value, the lower is the amount of methylation observed. The periodontitis group had a higher mean Ct value as compared to the control group; indicating a lower amount of methylation in the promoter region of the periodontitis group as compared to the control group. A lower level of TNF alpha gene promoter (-239,-245) methylation was observed in the periodontitis group as compared to the controls and this observation appears to support a de-methylation of the TNF alpha promoter in the periodontitis subjects. Further studies evaluating the transcript levels of TNF alpha needs to be performed to confirm the observations of this study.