DNA methylation status of the IL8 gene promoter in oral cells of smokers and non-smokers with chronic periodontitis.
OBJECTIVE
This study analysed the status of DNA methylation in the promoter region of the IL8 gene in oral mucosa cells from healthy, smoker and non-smoker subjects with chronic periodontitis and compared these findings among groups with mRNA levels.


METHODS
Genomic DNA from epithelial oral cells of 41 healthy subjects, 30 smokers with chronic periodontitis and 40 non-smokers with chronic periodontitis were purified and modified by sodium bisulphite. Genomic DNA from blood leucocytes and gingival cells from biopsies of 13 subjects of each group were also purified and modified by sodium bisulphite. Modified DNA was submitted by methylation-specific polymerase chain reaction (PCR) (MSP), electrophoresed on 10% polyacrylamide gels and stained with SYBR Gold. Total RNA from gingival cells was also isolated using the TRIzol reagent, and real-time PCR performance was used to detect the levels of interleukin-8 mRNA.


RESULTS
Our results indicate that individuals with chronic periodontitis, independent of smoking habit, have a higher percentage of hipomethylation of the IL8 gene than those controls in epithelial oral cells (p<0.0001), and expression of higher levels of interleukin-8 (IL-8) mRNA than controls in gingival cells (p=0.007). No significant differences among groups were observed in gingival cells and blood cells.


CONCLUSIONS
We conclude that inflammation in the oral mucosa might lead to changes in the DNA methylation status of the IL8 gene in epithelial oral cells.
Oliveira
Naila F P
NF
Laboratory of Molecular Biology, Department of Morphology, Division of Histology, School of Dentistry of Piracicaba, University of Campinas-UNICAMP, Piracicaba, SP, Brazil.
Damm
Gilcy R
GR
Andia
Denise C
DC
Salmon
Cristiane
C
Nociti
Francisco H
FH
Line
Sérgio R P
SR
de Souza
Ana Paula
AP
D000328:Adult; D016022:Case-Control Studies; D055113:Chronic Periodontitis / Q000235:genetics* / Q000378:metabolism*; D018899:CpG Islands; D019175:DNA Methylation; D044127:Epigenesis, Genetic; D004847:Epithelial Cells / Q000378:metabolism; D005260:Female; D006801:Humans; D016209:Interleukin-8 / Q000235:genetics*; D008297:Male; D008875:Middle Aged; D009061:Mouth Mucosa / Q000166:cytology / Q000378:metabolism*; D016133:Polymerase Chain Reaction; D011401:Promoter Regions, Genetic; D012907:Smoking / Q000235:genetics* / Q000378:metabolism*
D016209:Interleukin-8