title: Expression, polymorphism and methylation pattern of interleukin-6 in periodontal tissues.
abstract: Periodontitis is considered an inflammatory disorder of bacterial etiology that results in periodontal tissue destruction, as a result of complex interactions between periodontal pathogens, host and immune response. Genetic and epigenetic mechanisms may modulate the individual response since it is able to influence the gene expression. The aim of this study was to evaluate the impact of -174 G/C polymorphism and the methylation status of the promoter region of IL-6 gene on the expression of IL-6 in gingival samples from individuals with chronic periodontitis. Gingival biopsies were collected from 21 patients with chronic periodontitis and 21 controls. Histologic sections stained by hematoxylin-eosin were used for histopathological evaluation. The IL-6 gene expression was assessed by quantitative real-time PCR. The polymorphism IL-6 -174 C/G was studied by polymerase chain reaction (PCR) amplification and restriction endonuclease digestion (HspII). Methylation-specific polymerase chain reaction was used to verify the DNA methylation pattern. The number of inflammatory cells in tissue fragments from individuals with chronic periodontitis was higher than in the control group and the inflammatory infiltrate was predominantly mononuclear. The expression of IL-6 was higher in the group with periodontitis. In polymorphism assay, no statistical difference in the distribution of genotypes and alleles in both groups were observed. The most of samples were partially methylated. No difference was observed in methylation pattern from two different regions of the IL-6 gene among groups. The high expression of IL-6 is an important factor related to chronic periodontitis, but was not associated with methylation status or the -174 (G/C) genetic polymorphism, suggesting that other mechanisms are involved in this gene transcription regulation.
authors: Laboratory of Molecular Biology, Department of Oral Surgery and Pathology, School of Dentistry, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil.
authors: Florença Abdanur
authors: FA
authors: Stefani
authors: Michelle Beatriz
authors: MB
authors: Viana
authors: Ana Carolina
authors: AC
authors: Dupim
authors: João Artur Ricieri
authors: JA
authors: Brito
authors: Ricardo Santiago
authors: RS
authors: Gomez
authors: José Eustáquio
authors: JE
authors: da Costa
authors: Paula Rocha
authors: PR
authors: Moreira
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000483:Alleles; D016022:Case-Control Studies; D055113:Chronic Periodontitis / Q000235:genetics* / Q000276:immunology / Q000473:pathology; D019175:DNA Methylation; D005260:Female; D005786:Gene Expression Regulation; D005787:Gene Frequency; D005838:Genotype; D005881:Gingiva / Q000276:immunology* / Q000473:pathology; D006801:Humans; D015850:Interleukin-6 / Q000235:genetics* / Q000276:immunology; D007963:Leukocytes, Mononuclear / Q000276:immunology / Q000473:pathology; D008297:Male; D008875:Middle Aged; D020641:Polymorphism, Single Nucleotide; D011401:Promoter Regions, Genetic
chemical_list: C508600:IL6 protein, human; D015850:Interleukin-6