TY - JOUR
T1 - TLR-2 gene methylation in peripheral blood monocytes from apical periodontitis individuals
T2 - A cross-sectional study
AU - Bordagaray, María José
AU - Fernández, Alejandra
AU - Pellegrini, Elizabeth
AU - Garrido, Mauricio
AU - Hernández, Patricia
AU - González-Quintanilla, David
AU - Navia, Gabriel
AU - Rehbein, Daniela
AU - Baeza, Mauricio
AU - Gebicke-Haerter, Peter
AU - Hernández, Marcela
N1 - Publisher Copyright:
© 2025 British Endodontic Society. Published by John Wiley & Sons Ltd.
PY - 2025
Y1 - 2025
N2 - Aim: Apical periodontitis (AP) is a chronic inflammatory disease arising from the contamination of the root canal system. Epigenetic regulation plays a pivotal role in controlling monocyte/macrophage-mediated local and systemic responses to bacterial challenges via toll-like receptors (TLRs). We aimed to explore the relationship between the methylation and expression patterns of TLR-2 in peripheral blood monocytes of individuals with AP and controls. Methodology: Cross-sectional study. Otherwise healthy individuals with AP (n = 25) and controls (n = 29) were recruited. Peripheral blood monocytes were isolated from blood samples by Ficoll gradient and negative immunoselection. DNA and RNA were extracted from monocytes. DNA was bisulfite-treated, amplified and sequenced to evaluate the global and cytosine-phosphate-guanine (CpG) single-site methylation pattern of the TLR-2 gene promoter. mRNA relative levels of TLR-2 were assessed by qPCR. The potential associations between AP, TLR-2 DNA methylation and TLR-2 gene expression were explored using generalized structural equation models (GSEM). Results: TLR-2 expression was significantly upregulated in peripheral blood monocytes from individuals with AP compared to controls (p = 0.005). Though no differences were found in the global methylation pattern, CpG single sites from the TLR-2 gene were differentially methylated at positions −40 and +24 (p < 0.05). The methylated positions at −40 and −20 in TLR-2 were associated with TLR-2 transcriptional upregulation (p < 0.05). Further evaluation with GSEM analysis showed that AP promoted the methylation of the −40 CpG single site on the TLR-2 gene, which, in turn, upregulated TLR-2. Conversely, the methylation of the −20 CpG single site did not act as a mediator of TLR-2 transcription in AP. Conclusions: AP diagnosis activates peripheral blood monocytes via −40 CpG single-site methylation, independently promoting TLR-2 expression.
AB - Aim: Apical periodontitis (AP) is a chronic inflammatory disease arising from the contamination of the root canal system. Epigenetic regulation plays a pivotal role in controlling monocyte/macrophage-mediated local and systemic responses to bacterial challenges via toll-like receptors (TLRs). We aimed to explore the relationship between the methylation and expression patterns of TLR-2 in peripheral blood monocytes of individuals with AP and controls. Methodology: Cross-sectional study. Otherwise healthy individuals with AP (n = 25) and controls (n = 29) were recruited. Peripheral blood monocytes were isolated from blood samples by Ficoll gradient and negative immunoselection. DNA and RNA were extracted from monocytes. DNA was bisulfite-treated, amplified and sequenced to evaluate the global and cytosine-phosphate-guanine (CpG) single-site methylation pattern of the TLR-2 gene promoter. mRNA relative levels of TLR-2 were assessed by qPCR. The potential associations between AP, TLR-2 DNA methylation and TLR-2 gene expression were explored using generalized structural equation models (GSEM). Results: TLR-2 expression was significantly upregulated in peripheral blood monocytes from individuals with AP compared to controls (p = 0.005). Though no differences were found in the global methylation pattern, CpG single sites from the TLR-2 gene were differentially methylated at positions −40 and +24 (p < 0.05). The methylated positions at −40 and −20 in TLR-2 were associated with TLR-2 transcriptional upregulation (p < 0.05). Further evaluation with GSEM analysis showed that AP promoted the methylation of the −40 CpG single site on the TLR-2 gene, which, in turn, upregulated TLR-2. Conversely, the methylation of the −20 CpG single site did not act as a mediator of TLR-2 transcription in AP. Conclusions: AP diagnosis activates peripheral blood monocytes via −40 CpG single-site methylation, independently promoting TLR-2 expression.
KW - DNA methylation
KW - monocytes
KW - periapical periodontitis
KW - toll-like receptor-2
UR - http://www.scopus.com/inward/record.url?scp=105006785601&partnerID=8YFLogxK
U2 - 10.1111/iej.14255
DO - 10.1111/iej.14255
M3 - Article
AN - SCOPUS:105006785601
SN - 0143-2885
JO - International Endodontic Journal
JF - International Endodontic Journal
ER -