IADR Abstract Archives
Epigenetic regulation of TLR2-mediated inflammation in extra-radicular infection
Objectives: To assess bacterial loads of Porphyromonas sp.and the modulation of the inflammatory response through Toll-like receptor (TLR)2 DNA methylation in symptomatic and asymptomatic apical lesions
Methods: Cross-sectional study. Apical lesions were obtained from volunteers with asymptomatic apical periodontitis (AAP) (n=17) and symptomatic apical periodontitis (SAP) (n=17) having indication of tooth extraction, and both total RNA and DNA were extracted. TLR2, IL-6, TNF-a, IL-10,and TGF-bmRNA levels were quantified by qPCR. DNA was bisulfited, amplified by qPCR using a previously validated primer for the CpG island on its promoter, and the products were sequenced. The results were analyzed by BiQanalyzer. Additionally, the bacterial DNA was extracted using lysis buffer containing lysozyme (AAP n= 29; SAP n=35) for P. endodontalis,P. gingivalisand total bacterial quantification by qPCR using validated primers
Results: The frequencies of detection of P. endondotalis, P. gingivalis and total bacteria were 6.9%, 13.8% and 65.5% in PAA and 37.1%, 22.9% and 72.2% in PAS, respectively; but differences were statistically significant only for detection of P. endodontalis(p<0.05). SAP demonstrated a hypomethylated DNA profile at the TLR2 CpG island compared to AAP, along with up-regulated expression of TLR2 and pro-inflammatory cytokine IL-6; while TLR2 hypomethylation associated with IL-10 levels in SAP. (p <0.05). Specifically, lower methylation frequencies of CpG dinucleotides localized in -8, -10 (binding sites for NF-κB) and -142 (binding site for Sp1) from TLR2 promoter were identified in SAP versus AAP (p<0.05).
Conclusions: TLR2-mediated inflammation can be epigenetically regulated in symptomatic apical lesions through DNA hypomethylation, favoring the binding of the main transcription factors responsible for the induction of TLR2 transcription inresponse to bacterial challenge
Methods: Cross-sectional study. Apical lesions were obtained from volunteers with asymptomatic apical periodontitis (AAP) (n=17) and symptomatic apical periodontitis (SAP) (n=17) having indication of tooth extraction, and both total RNA and DNA were extracted. TLR2, IL-6, TNF-a, IL-10,and TGF-bmRNA levels were quantified by qPCR. DNA was bisulfited, amplified by qPCR using a previously validated primer for the CpG island on its promoter, and the products were sequenced. The results were analyzed by BiQanalyzer. Additionally, the bacterial DNA was extracted using lysis buffer containing lysozyme (AAP n= 29; SAP n=35) for P. endodontalis,P. gingivalisand total bacterial quantification by qPCR using validated primers
Results: The frequencies of detection of P. endondotalis, P. gingivalis and total bacteria were 6.9%, 13.8% and 65.5% in PAA and 37.1%, 22.9% and 72.2% in PAS, respectively; but differences were statistically significant only for detection of P. endodontalis(p<0.05). SAP demonstrated a hypomethylated DNA profile at the TLR2 CpG island compared to AAP, along with up-regulated expression of TLR2 and pro-inflammatory cytokine IL-6; while TLR2 hypomethylation associated with IL-10 levels in SAP. (p <0.05). Specifically, lower methylation frequencies of CpG dinucleotides localized in -8, -10 (binding sites for NF-κB) and -142 (binding site for Sp1) from TLR2 promoter were identified in SAP versus AAP (p<0.05).
Conclusions: TLR2-mediated inflammation can be epigenetically regulated in symptomatic apical lesions through DNA hypomethylation, favoring the binding of the main transcription factors responsible for the induction of TLR2 transcription inresponse to bacterial challenge