TY - JOUR
T1 - Role of TLR9 methylation on its active transcription in apical inflammation
AU - Fernández, Alejandra
AU - Astorga, Jessica
AU - Bordagaray, María José
AU - Lira, María Jesús
AU - Gebicke-Haerter, Peter J.
AU - Hernández, Marcela
N1 - Publisher Copyright:
© 2022 International Endodontic Journal. Published by John Wiley & Sons Ltd.
PY - 2022
Y1 - 2022
N2 - Aim: To explore the methylation pattern, its role in transcriptional regulation and potential modifiers of methylation of the TLR9 gene in chronic periapical inflammation. Methodology: In this cross-sectional study, apical lesions of endodontic origin (ALEO, n = 61) and healthy periodontal ligaments (HPL, n = 15) were included. Products from bisulfited and PCR-amplified DNA were analysed for their methylation profiles in the promoter region and at each CpG island. Additionally, TLR9 mRNA levels were quantified by qPCR and bivariate and multiple modelling were performed to better understand the influence of methylation on gene transcription. Results: TLR9 mRNA levels were upregulated in ALEO compared to HPL (p <.001). TLR9 promoter CpG sites and CpG +2086 in the intragenic island 1 were demethylated in ALEO compared to HPL (p <.05). Multivariate analysis, adjusted by smoking and gender, revealed that demethylation of TLR9 promoter sites enhanced transcriptional activity, specifically demethylated CpGs at positions −736 and −683, (p =.02), which are close to CRE binding. Although ALEO reduced the global methylation of the gene promoter and intragenic-island 2 (p <.05) by −42.5 and −9.5 percentage points, respectively, age reduced the global methylation of intragenic-island 3 within the exon 2. Conclusions: Demethylations of TLR9 promoter CpG sites, along with the intragenic DNA methylation status, were involved in higher transcription in ALEO. Hence, chronic periapical inflammation and ageing modify the methylation status both in the gene promoter and in intragenic CpG islands.
AB - Aim: To explore the methylation pattern, its role in transcriptional regulation and potential modifiers of methylation of the TLR9 gene in chronic periapical inflammation. Methodology: In this cross-sectional study, apical lesions of endodontic origin (ALEO, n = 61) and healthy periodontal ligaments (HPL, n = 15) were included. Products from bisulfited and PCR-amplified DNA were analysed for their methylation profiles in the promoter region and at each CpG island. Additionally, TLR9 mRNA levels were quantified by qPCR and bivariate and multiple modelling were performed to better understand the influence of methylation on gene transcription. Results: TLR9 mRNA levels were upregulated in ALEO compared to HPL (p <.001). TLR9 promoter CpG sites and CpG +2086 in the intragenic island 1 were demethylated in ALEO compared to HPL (p <.05). Multivariate analysis, adjusted by smoking and gender, revealed that demethylation of TLR9 promoter sites enhanced transcriptional activity, specifically demethylated CpGs at positions −736 and −683, (p =.02), which are close to CRE binding. Although ALEO reduced the global methylation of the gene promoter and intragenic-island 2 (p <.05) by −42.5 and −9.5 percentage points, respectively, age reduced the global methylation of intragenic-island 3 within the exon 2. Conclusions: Demethylations of TLR9 promoter CpG sites, along with the intragenic DNA methylation status, were involved in higher transcription in ALEO. Hence, chronic periapical inflammation and ageing modify the methylation status both in the gene promoter and in intragenic CpG islands.
KW - CpG island
KW - DNA methylation
KW - infection
KW - periapical periodontitis
KW - RNA messenger
KW - toll-like receptor 9
UR - http://www.scopus.com/inward/record.url?scp=85128782221&partnerID=8YFLogxK
U2 - 10.1111/iej.13745
DO - 10.1111/iej.13745
M3 - Article
AN - SCOPUS:85128782221
SN - 0143-2885
JO - International Endodontic Journal
JF - International Endodontic Journal
ER -