Epstein–Barr virus reactivation by persistent apical periodontal pathogens

Abstract

Aim To assess whether Epstein–Barr virus (EBV) reactivation is triggered by persistent apical periodontitis‐related microbes using in vitro and ex vivo methodologies. Methodology Surgically removed human periapical granulomas (n = 50) and healthy gingival tissues (n = 10) were analysed to determine the presence of EBV and seven persistent apical periodontitis‐related microbes. In addition, real‐time polymerase chain reaction was used to detect the mRNA expression of BZLF‐1, an immediate–early gene of EBV. Expression of latent membrane protein (LMP)‐1 and ZEBRA, an early lytic protein of EBV encoded by BZLF‐1, was also examined using triple‐colour immunofluorescence staining. n‐Butyric acid produced by the microbes was quantified, and luciferase assays were performed in association with bacterial lysates. In addition, Daudi cells were cultured with bacterial lysates, and the expression levels of BZLF‐1 mRNA and ZEBRA protein were determined. Results EBV DNA and BZLF‐1 mRNA were detected in 47 out of 50 periapical granulomas, but not in healthy gingival tissues. The EBV DNA copy number and the number of Fusobacterium nucleatum were significantly positively correlated with BZLF‐1 expression in periapical granulomas. The number of Prevotella intermedia was slightly correlated with BZLF‐1 expression; however, the other microbes were not. CD79a‐positive B cells in periapical granulomas, but not those in healthy gingival tissues, expressed both LMP‐1 and ZEBRA. n‐Butyric acid production was the highest in F. nucleatum and the lowest in P. intermedia. Enterococcus faecalis, Candida albicans and the other tested microbes did not produce n‐butyric acid. An F. nucleatum lysate exhibited significantly increased BZLF‐1‐luciferase activity in the same manner of commercial butyric acid, whereas P. intermedia did not. F. nucleatum also induced the expression of BZLF‐1 mRNA and ZEBRA protein by Daudi cells, indicating that EBV reactivation was induced. Conclusion Among the persistent apical periodontitis‐related bacteria that were tested, F. nucleatum most strongly reactivated latent EBV, whereas E. faecalis and C. albicans as well as the other microbes did not.

How Does Epstein–Barr Virus Contribute to Chronic Periodontitis?

“…In this regard, EBV was recently suggested to be involved in the pathogenesis of other chronic inflammatory infections occurring in the periodontium such as peri-implantitis and periapical periodontitis [50][51][52]. In contrast with unexplained peri-implantitis, some interesting mechanisms are reported with periapical periodontitis, i.e., BA excreted by P. endodontalis and F. nucleatum in addition to EBV is involved in the progression of periapical periodontitis [53,54]. An underlying mechanism may involve reactive oxygen species released from EBV-infected host cells that induce local imbalance between receptor activator NF-κB and osteoprotegerin, which consequently promotes alveolar bone resorption [55].…”

Interactions Between Streptococcus gordonii and Fusobacterium nucleatum Altered Bacterial Transcriptional Profiling and Attenuated the Immune Responses of Macrophages

“…Last but not least, it is a well-known fact that production of butyrate is an important virulence for F. nucleatum. F. nucelatum utilizes amino acids such as glutamate, lysine, and fructose as an energy source and produce SCFAs including butyrate (Himi et al, 2020;Llama-Palacios et al, 2020). Although we didn't identify relevant DEGs in F. nucelatum subsp.…”

How Does Epstein–Barr Virus Interact With Other Microbiomes in EBV-Driven Cancers?

“…It is reported that P. gingivalis and F. nucleatum can take part in the regulation of acetylation and deacetylase for histone, thus reactivating the EBV by modulating the BZLF1 promoter in EBV-infected cells ( Imai et al., 2012a ; Imai et al., 2012c ). Butyrate (BA), which belongs to a short-chain fatty acid (SCFA) family ( Louis et al., 2010 ; Imai et al., 2012b ), was reported to be excreted by P. endodontalis and F. nucleatum in EBV carriers, and leads to the occurrences of periapical periodontitis ( Makino et al., 2018 ; Himi et al., 2020 ). In addition, studies have also declared that the intraperitoneal injection of BA in EBV-driven cancers accelerates the expression of ZEBRA expression and reactivate the lytic EBV replication ( Westphal et al., 1999 ; Westphal et al., 2000 ).…”