Interferon‐gamma promoter hypomethylation and increased expression in chronic periodontitis

Abstract

Aim The goal of this investigation was to determine whether epigenetic modifications in the IFNG promoter are associated with an increase of IFNG transcription in different stages of periodontal diseases. Materials and Methods DNA was extracted from gingival biopsy samples collected from 47 total sites from 47 different subjects: 23 periodontally healthy sites, 12 experimentally induced gingivitis sites and 12 chronic periodontitis sites. Levels of DNA methylation within the IFNG promoter containing six CpG dinucleotides were determined using pyrosequencing technology. Interferon gamma mRNA expression was analysed by quantitative polymerase chain reactions using isolated RNA from part of the biological samples mentioned above. Results The methylation level of all six analysed CpG sites within the IFNG promoter region in the periodontitis biopsies {52% [interquartile range, IQR (43.8%, 63%)]} was significantly lower than periodontally healthy samples {62% [IQR (51.3%, 74%)], p =0.007} and gingivitis biopsies {63% [IQR (55%, 74%)], p =0.02}. The transcriptional level of IFNG in periodontitis biopsies was 1.96-fold and significantly higher than tissues with periodontal health (p =0.04). Although the mRNA level from experimental gingivitis samples exhibited an 8.5-fold increase as compared with periodontally healthy samples, no significant methylation difference was observed in experimental gingivitis sample. Conclusions A hypomethylation profile within IFNG promoter region is related to an increase of IFNG transcription present in the chronic periodontitis biopsies, while such an increase of IFNG in experimentally induced gingivitis seems independent of promoter methylation alteration.

Expression, polymorphism and methylation pattern of interleukin-6 in periodontal tissues

“…However, the same was not observed when assessed DNA from gingival tissue cells in chronic periodontitis (Oliveira et al 2009). Zhang et al (2010) showed that hypomethylation in interferon-gamma (IFN-) promoter region is associated with an increase of IFN-␥ expression in chronic periodontitis biopsies. Viana et al (2011) reported that methylation status of the IFN-and IL-10 genes was similar in periodontal tissues with chronic periodontitis and control group.…”

The Role of Epigenetics on Dental Implant Therapy: A Systematic Review

“…Several authors have investigated the role of epigenetics in chronic or aggressive periodontitis [36][37][38], and have demonstrated that the expression levels of cytokines and chemokines [39], toll-like receptors [40], protease-activated receptors [41], interleukin-8 [42], and cyclooxygenase-2 [37,38] could be affected by oral bacteria. A recent study documented that the presence of different oral bacteria resulted in a differential methylation profile in gingival epithelia [43], while another article demonstrated hypomethylated oral epithelia in patients with generalized aggressive periodontitis [36].…”

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“…[32] Methylation patterns may be different between healthy and inflamed dental pulp. [33] Histone modification Post-translational modification of core histones, by either condensing or relaxing chromatin, regulates gene transcription making it a crucial epigenetic mechanism.…”