Campos Kelma, Franscisconi Carolina F, Okehie Valerie, de Souza Letícia C, Trombone Ana Paula F, Letra Ariadne, Garlet Gustavo P, Gomez Ricardo S, Silva Renato M
Department of Oral Surgery and Pathology, Federal University of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil.
Department of Biological Sciences, School of Dentistry of Bauru, University of Sao Paulo, Bauru, São Paulo, Brazil.
J Endod. 2015 Feb;41(2):212-8. doi: 10.1016/j.joen.2014.10.003. Epub 2014 Nov 11.
Epigenetic mechanisms, such as DNA methylation, can modify gene expression patterns without changing the DNA sequence, comprising a tool that cells use to lock genes in the "off" position. Variations in the methylation profile have been correlated to a variety of human diseases. Here, we hypothesize that DNA methylation in immune response-related genes may contribute to the development of periapical lesions.
The DNA methylation patterns of 22 immune response-related gene promoters were evaluated in 137 human periapical granulomas, 8 apical cysts, and 31 healthy gingival tissues from 2 independent cohorts using a pathway-specific real-time polymerase chain reaction array (EpiTect Methyl II; Qiagen Inc, Valencia, CA). Messenger RNA expression analysis by qualitative polymerase chain reaction was also performed. SABiosciences's hierarchical clustering and methylation (Qiagen, Valencia, CA) and Prism6 software (GraphPad Software, Inc, La Jolla, CA) were used for data analysis.
FOXP3 gene promoter showed the highest level of methylation in both periapical granulomas and apical cysts (P < .001), and methylation levels were inversely correlated with FOXP3 messenger RNA expression in the lesions. Furthermore, FOXP3 expression was prevalent in inactive lesions and was positively correlated with interleukin-10 and transforming growth factor beta levels.
Our results suggest that FOXP3 acts as a master switch governing the development and function of T-regulatory cells, whose functions include the inhibition of immune responses and temper inflammation. The observed differential methylation patterns of FOXP3 in periapical lesions may be crucial in determining its suppressive activity and may be involved in periapical lesion development.
表观遗传机制，如DNA甲基化，可在不改变DNA序列的情况下修饰基因表达模式，是细胞用于将基因锁定在“关闭”位置的一种工具。甲基化谱的变化与多种人类疾病相关。在此，我们假设免疫反应相关基因中的DNA甲基化可能促成根尖周病变的发生。
使用通路特异性实时聚合酶链反应阵列（EpiTect Methyl II；Qiagen公司，加利福尼亚州瓦伦西亚），在来自2个独立队列的137例人类根尖周肉芽肿、8例根尖囊肿和31例健康牙龈组织中，评估22个免疫反应相关基因启动子的DNA甲基化模式。还通过定性聚合酶链反应进行信使核糖核酸表达分析。使用SABiosciences的层次聚类和甲基化（Qiagen，加利福尼亚州瓦伦西亚）以及Prism6软件（GraphPad软件公司，加利福尼亚州拉霍亚）进行数据分析。
FOXP3基因启动子在根尖周肉芽肿和根尖囊肿中均显示出最高水平的甲基化（P <.001），且甲基化水平与病变中FOXP3信使核糖核酸的表达呈负相关。此外，FOXP3表达在非活动性病变中普遍存在，且与白细胞介素-10和转化生长因子β水平呈正相关。
我们的结果表明，FOXP3作为一种主开关，控制着调节性T细胞的发育和功能，其功能包括抑制免疫反应和减轻炎症。在根尖周病变中观察到的FOXP3不同甲基化模式可能对确定其抑制活性至关重要，并可能参与根尖周病变的发生发展。
