EBV infection is common in gingival epithelial cells of the periodontium and worsens during chronic periodontitis

Epstein-Barr Virus Promotes Inflammatory Cytokine Production in Human Gingival Fibroblasts

BACKGROUND

Periodontitis is one of the most common chronic oral inflammatory diseases. Over the past decade, herpes viruses, particularly Epstein-Barr virus (EBV), have been considered promising pathogenic candidates for periodontitis. However, the specific mechanism by which EBV contributes to the development of periodontitis is still unknown. This study aimed to explore the mechanism of EBV underlying the inflammatory response in human gingival fibroblasts (HGFs).

MATERIALS AND METHODS

HGFs were stimulated with different concentrations of EBV (104, 105, 106, 107, and 108 DNA copies/mL) for 0, 8, 24, or 48 hours. The mRNA levels of interleukin (IL)-1β, tumour necrosis factor-α (TNF-α), IL-8, monocyte chemoattractant protein-1 (MCP-1), and Toll-like receptor 9 (TLR9) were measured using quantitative real-time polymerase chain reaction (PCR). Enzyme-linked immunosorbent assays (ELISAs) were performed for determining the mRNA and protein levels of IL-1β, TNF-α, IL-8, and MCP-1. Real-time PCR and ELISA were performed to determine the protein levels of IL-1β, TNF-α, IL-8, and MCP-1. Activation of the TLR9/myeloid differentiation factor 88 (MyD88)/nuclear factor kappa B (NF-κB) pathway was evaluated using western blotting.

RESULTS

The expressions of IL-1β, TNF-α, IL-8, and MCP-1 were significantly upregulated in HGFs under EBV stimulation in a concentration- and time-dependent manner. EBV promoted TLR9 and MyD88 expression and induced NF-κB transcription. On the contrary, the upregulation of these factors and the activation of NF-κB pathway were drastically inhibited by TLR9 antagonists.

CONCLUSIONS

Our findings demonstrate that EBV promotes the production of inflammatory cytokines IL-1β and TNF-α and chemokines IL-8 and MCP-1 in HGFs through the TLR9/MyD88/NF-κB pathway.

Human immunodeficiency virus and oral microbiota: mutual influence on the establishment of a viral gingival reservoir in individuals under antiretroviral therapy

The role of the oral microbiota in the overall health and in systemic diseases has gained more importance in the recent years, mainly due to the systemic effects that are mediated by the chronic inflammation caused by oral diseases, such as periodontitis, through the microbial communities of the mouth. The chronic infection by the human immunodeficiency virus (HIV) interacts at the tissue level (e.g. gut, genital tract, brain) to create reservoirs; the modulation of the gut microbiota by HIV infection is a good example of these interactions. The purpose of the present review is to assess the state of knowledge on the oral microbiota (microbiome, mycobiome and virome) of HIV-infected patients in comparison to that of HIV-negative individuals and to discuss the reciprocal influence of HIV infection and oral microbiota in patients with periodontitis on the potential establishment of a viral gingival reservoir. The influence of different clinical and biological parameters are reviewed including age, immune and viral status, potent antiretroviral therapies, smoking, infection of the airway and viral coinfections, all factors that can modulate the oral microbiota during HIV infection. The analysis of the literature proposed in this review indicates that the comparisons of the available studies are difficult due to their great heterogeneity. However, some important findings emerge: (i) the oral microbiota is less influenced than that of the gut during HIV infection, although some recurrent changes in the microbiome are identified in many studies; (ii) severe immunosuppression is correlated with altered microbiota and potent antiretroviral therapies correct partially these modifications; (iii) periodontitis constitutes a major factor of dysbiosis, which is exacerbated in HIV-infected patients; its pathogenesis can be described as a reciprocal reinforcement of the two conditions, where the local dysbiosis present in the periodontal pocket leads to inflammation, bacterial translocation and destruction of the supporting tissues, which in turn enhances an inflammatory environment that perpetuates the periodontitis cycle. With the objective of curing viral reservoirs of HIV-infected patients in the future years, it appears important to develop further researches aimed at defining whether the inflamed gingiva can serve of viral reservoir in HIV-infected patients with periodontitis.

Detection of Epstein-Barr virus infection in primary junctional epithelial cell cultures

Background

Junctional epithelium (JE) provides the front-line defense against pathogens invading periodontium. The breakdown of the JE barrier is the hallmark of periodontitis. Recent studies have implicated the Epstein-Barr virus (EBV) as one of the etiopathogenetic factors of periodontitis. EBV exhibits tropism for two target cells in vivo: B cells, where it primarily remains latent, and epithelial cells, where viral replication occurs.

Objective

Our knowledge of junctional epithelial cell (JEC) infection with EBV has been limited by the difficulty of generating cell cultures and the inability to infect JECs in vitro readily.

Design

To study EBV infection in JECs, we developed human JEC cultures derived from a periodontitis patient. Furthermore, we established a successful contact-free co-culture infection model between the EBV-donor B95-8 cell line and the EBV-permissive JEC culture. JECs and EBV infection of JECs were detected using immunofluorescent staining of cytokeratin 19 and EBNA1, respectively. In addition, EBV infection was confirmed by RT-qPCR for EBNA1, LMP1, and BZLF1 expression.

Results and conclusions

Our results suggest that the infection of JECs with EBV can occur in an in vitro experimental model. These outcomes have the potential to enhance our understanding of EBV's involvement in periodontitis and advance periodontal research.

A distinct isoform of lymphoid enhancer binding factor 1 (LEF1) epigenetically restricts EBV reactivation to maintain viral latency

As a human tumor virus, EBV is present as a latent infection in its associated malignancies where genetic and epigenetic changes have been shown to impede cellular differentiation and viral reactivation. We reported previously that levels of the Wnt signaling effector, lymphoid enhancer binding factor 1 (LEF1) increased following EBV epithelial infection and an epigenetic reprogramming event was maintained even after loss of the viral genome. Elevated LEF1 levels are also observed in nasopharyngeal carcinoma and Burkitt lymphoma. To determine the role played by LEF1 in the EBV life cycle, we used in silico analysis of EBV type 1 and 2 genomes to identify over 20 Wnt-response elements, which suggests that LEF1 may bind directly to the EBV genome and regulate the viral life cycle. Using CUT&RUN-seq, LEF1 was shown to bind the latent EBV genome at various sites encoding viral lytic products that included the immediate early transactivator BZLF1 and viral primase BSLF1 genes. The LEF1 gene encodes various long and short protein isoforms. siRNA depletion of specific LEF1 isoforms revealed that the alternative-promoter derived isoform with an N-terminal truncation (ΔN LEF1) transcriptionally repressed lytic genes associated with LEF1 binding. In addition, forced expression of the ΔN LEF1 isoform antagonized EBV reactivation. As LEF1 repression requires histone deacetylase activity through either recruitment of or direct intrinsic histone deacetylase activity, siRNA depletion of LEF1 resulted in increased histone 3 lysine 9 and lysine 27 acetylation at LEF1 binding sites and across the EBV genome. Taken together, these results indicate a novel role for LEF1 in maintaining EBV latency and restriction viral reactivation via repressive chromatin remodeling of critical lytic cycle factors.

Conditional Cell Reprogramming and Air-Liquid Interface Modeling Life Cycle of Oncogenic Viruses (HPV and EBV) in Epithelial Cells and Virus-Associated Human Carcinomas

Several oncogenic viruses are associated with approximately 20% of human cancers. Experimental models are crucial for studying the pathogenicity and biological aspects of oncogenic viruses and their potential mechanisms in tumorigenesis. Current cell models have considerable limitations such as: their low yield, genetic and epigenetic modification, and reduction in tumor heterogeneity during long propagation. Cancer cell lines are limited and not appropriate for studying the viral life cycle, for example, natural viral life cycles of HPV and EBV, and their persistence and latency in epithelial cells are poorly understood, since these processes are highly related to epithelial differentiation. Therefore, there is an urgent need of reliable human physiological cell models to study viral life cycle and cancer initiation. Conditional cell reprogramming (CCR) is a rapid and robust cell culture system, where the cells can be established from minimally invasive or noninvasive specimens and their lineage functions preserved during the long-term culture. These CR cells retain their ability to differentiate at air-liquid interface (ALI). Here, we recapitulated the applications of CR and ALI approaches in modeling host-virus interactions and viral-mediated tumorigenesis.

IL-8 Secreted by Gastric Epithelial Cells Infected with Helicobacter pylori CagA Positive Strains Is a Chemoattractant for Epstein–Barr Virus Infected B Lymphocytes

Helicobacter pylori and EBV are considered the main risk factors in developing gastric cancer. Both pathogens establish life-lasting infections and both are considered carcinogenic in humans. Different lines of evidence support that both pathogens cooperate to damage the gastric mucosa. Helicobacter pylori CagA positive virulent strains induce the gastric epithelial cells to secrete IL-8, which is a potent chemoattractant for neutrophils and one of the most important chemokines for the bacterium-induced chronic gastric inflammation. EBV is a lymphotropic virus that persists in memory B cells. The mechanism by which EBV reaches, infects and persists in the gastric epithelium is not presently understood. In this study, we assessed whether Helicobacter pylori infection would facilitate the chemoattraction of EBV-infected B lymphocytes. We identified IL-8 as a powerful chemoattractant for EBV-infected B lymphocytes, and CXCR2 as the main IL-8 receptor whose expression is induced by the EBV in infected B lymphocytes. The inhibition of expression and/or function of IL-8 and CXCR2 reduced the ERK1/2 and p38 MAPK signaling and the chemoattraction of EBV-infected B lymphocytes. We propose that IL-8 at least partially explains the arrival of EBV-infected B lymphocytes to the gastric mucosa, and that this illustrates a mechanism of interaction between Helicobacter pylori and EBV.

New insight into Epstein-Barr virus infection using models of stratified epithelium

Epstein-Barr virus (EBV) is a ubiquitous human pathogen that is transmitted in saliva. EBV transits through the oral epithelium to infect B cells, where it establishes a life-long latent infection. Reinfection of the epithelium is believed to be mediated by virus shed from B cells, but whether a latent reservoir can exist in the epithelia is unknown. We previously developed an in vitro organotypic model of stratified epithelium where EBV can readily replicate within the suprabasal layers of the epithelium following apical infection mediated by virus-producing B cells. Given that infected epithelial cells and cell-free virus are observed in saliva, we examined the ability of both of these to mediate infection in organotypic cultures. Epithelial-derived cell-free virus was able to infect organotypic cultures from the apical surface, but showed enhanced infection of B cells. Conversely, B cell-derived virus exhibited enhanced infection of epithelial cells. While EBV has been detected in basal cells in oral hairy leukoplakia, it is unknown whether EBV can be seen in undifferentiated primary keratinocytes in the basal layer. Undifferentiated epithelial cells expressed proposed EBV receptors in monolayer and were susceptible to viral binding and entry. Integrins, and occasionally ephrin A2, were expressed in the basal layer of gingiva and tonsil derived organotypic cultures, but the known B-cell receptors HLAII and CD21 were not detected. Following infection with cell-free virus or virus-producing B cells at either the apical or basolateral surface of preformed organotypic cultures, abundant infection was detected in differentiated suprabasal cells while more limited but readily detectable infection was observed in the undifferentiated basal cells. Together, our data has provided new insight into EBV infection in stratified epithelium.

EBV Association with Lymphomas and Carcinomas in the Oral Compartment

Epstein-Barr virus (EBV) is an oncogenic human herpesvirus infecting approximately 90% of the world's population. The oral cavity serves a central role in the life cycle, transmission, and pathogenesis of EBV. Transmitted to a new host via saliva, EBV circulates between cellular compartments within oral lymphoid tissues. Epithelial cells primarily support productive viral replication, while B lymphocytes support viral latency and reactivation. EBV infections are typically asymptomatic and benign; however, the latent virus is associated with multiple lymphomas and carcinomas arising in the oral cavity. EBV association with cancer is complex as histologically similar cancers often test negative for the virus. However, the presence of EBV is associated with distinct features in certain cancers. The intrinsic ability of EBV to immortalize B-lymphocytes, via manipulation of survival and growth signaling, further implicates the virus as an oncogenic cofactor. A distinct mutational profile and burden have been observed in EBV-positive compared to EBV-negative tumors, suggesting that viral infection can drive alternative pathways that converge on oncogenesis. Taken together, EBV is also an important prognostic biomarker that can direct alternative therapeutic approaches. Here, we discuss the prevalence of EBV in oral malignancies and the EBV-dependent mechanisms associated with tumorigenesis.

Epstein-Barr Virus Promotes the Production of Inflammatory Cytokines in Gingival Fibroblasts and RANKL-Induced Osteoclast Differentiation in RAW264.7 Cells

Periodontitis is an inflammatory condition that causes the destruction of the supporting tissues of teeth and is a major public health problem affecting more than half of the adult population worldwide. Recently, members of the herpes virus family, such as the Epstein–Barr virus (EBV), have been suggested to be involved in the etiology of periodontitis because bacterial activity alone does not adequately explain the clinical characteristics of periodontitis. However, the role of EBV in the etiology of periodontitis is unknown. This study aimed to examine the effect of inactivated EBV on the expression of inflammatory cytokines in human gingival fibroblasts (HGFs) and the induction of osteoclast differentiation. We found that extremely high levels of interleukin (IL)-6 and IL-8 were induced by inactivated EBV in a copy-dependent manner in HGFs. The levels of IL-6 and IL-8 in HGFs were higher when the cells were treated with EBV than when treated with lipopolysaccharide and lipoteichoic acid. EBV induced IκBα degradation, NF-κB transcription, and RAW264.7 cell differentiation into osteoclast-like cells. These findings suggest that even without infecting the cells, EBV contributes to inflammatory cytokine production and osteoclast differentiation by contact with oral cells or macrophage lineage, resulting in periodontitis onset and progression.

High-Risk Human Papillomavirus and Epstein-Barr Virus Coinfection: A Potential Role in Head and Neck Carcinogenesis

Simple Summary

A subset of carcinomas that arise in the head and neck region show a viral etiology. In fact, a subgroup of oropharyngeal cancers are caused by some types of human papillomavirus (HPV), so-called high-risk (HR)-HPVs, whereas undifferentiated nasopharyngeal carcinomas are etiologically related to Epstein–Barr virus (EBV). However, studies have reported the presence of both HR-HPV and EBV in some types of head and neck cancers. In this review, we discuss the potential contribution and role of HR-HPV/EBV coinfection in head and neck carcinogenesis, as well as the mechanisms that are potentially involved. In addition, HR-HPV/EBV interaction models are proposed.

Abstract

High-risk human papillomaviruses (HR-HPVs) and Epstein–Barr virus (EBV) are recognized oncogenic viruses involved in the development of a subset of head and neck cancers (HNCs). HR-HPVs are etiologically associated with a subset of oropharyngeal carcinomas (OPCs), whereas EBV is a recognized etiological agent of undifferentiated nasopharyngeal carcinomas (NPCs). In this review, we address epidemiological and mechanistic evidence regarding a potential cooperation between HR-HPV and EBV for HNC development. Considering that: (1) both HR-HPV and EBV infections require cofactors for carcinogenesis; and (2) both oropharyngeal and oral epithelium can be directly exposed to carcinogens, such as alcohol or tobacco smoke, we hypothesize possible interaction mechanisms. The epidemiological and experimental evidence suggests that HR-HPV/EBV cooperation for developing a subset of HNCs is plausible and warrants further investigation.

Masulili SL, Soeroso Y, Djoko Santoso W, S. Kusdhany L. Association between Epstein-Barr virus and periodontitis: A meta-analysis

Purpose

Previous studies have found that Epstein-Barr virus (EBV) is associated with periodontitis, though some controversy remains. This meta-analysis aimed to clarify and update the relationship between EBV and periodontitis as well as clinical parameters.

Methods

A comprehensive search was conducted in the PubMed and Scopus databases in December 2020. Original data were extracted according to defined inclusion and exclusion criteria. Outcomes were analyzed, including overall odds ratios (ORs) and 95% confidence intervals (CIs). A random-effects model was used, and publication bias was assessed by Egger’s and Begg’s tests. Sensitivity analysis was used to evaluate the stability of the outcome.

Results

Twenty-six studies were included in the present meta-analysis, involving 1354 periodontitis patients and 819 healthy controls. The included studies mostly showed high quality. The overall quantitative synthesis for the association between EBV and periodontitis was an increased odds ratio when subgingival EBV was detected OR = 7.069, 95% CI = 4.197–11.905, P<0.001). The results of subgroup analysis suggested that the association of EBV with periodontitis was significant in Asian, European, and American populations (P<0.001; P = 0.04; P = 0.003, respectively) but not in African populations (P = 0.29). Subgroup analysis by sample type showed that subgingival plaque (SgP), tissue and gingival crevicular fluid GCF were useful for EBV detection (P<0.001). EBV detection amplification methods included nested PCR, multiplex PCR and PCR (P<0.001; P = 0.05, P<0.001, respectively), but EBV detection by real-time PCR and loop-mediated isothermal amplification presented no significant result (P = 0.06; P = 0.3, respectively). For the clinical parameters of periodontitis, pocket depth (PD) and bleeding of probing (BOP) percentages were higher in the EBV-positive sites than in the EBV-negative sites (MD 0.47 [0.08, 0.85], P = 0.02; MD 19.45 [4.47, 34.43], P = 0.01).

Conclusions

A high frequency of EBV detection is associated with an increased risk of periodontitis. The EBV association was particularly significant in all populations except in African populations. Subgigival plaque (SgP), tissue and GCF were not significantly different useful material for detecting EBV in periodontitis. Nested PCR and multiplex PCR are reliable methods for this purpose. In the presence of EBV, PD and BOP are reliable clinical parameters for gingival inflammation. However, some caution in such interpretation is justified due to heterogeneity among studies. A suggested extension could assess the parallel influence of other human herpesviruses.

The human oral virome: Shedding light on the dark matter

Mediators of the initiation, development, and recurrence of periodontitis include the oral microbiome embedded in subgingival plaque and the host immune response to a dysbiosis within this dynamic and complex microbial community. Although mediators have been studied extensively, researchers in the field have been unable to fully ascribe certain clinical presentations of periodontitis to their nature. Emergence of high-throughput sequencing technologies has resulted in better characterization of the microbial oral dysbiosis that extends beyond the extensively studied putative bacterial periodontopathogens to a shift in the oral virome composition during disease conditions. Although the biological dark matter inserted by retroviruses was once believed to be nonfunctional, research has revealed that it encodes historical viral-eukaryotic interactions and influences host development. The objective of this review is to evaluate the proposed association of herpesviruses to the etiology and pathogenesis of periodontal disease and survey the highly abundant prokaryotic viruses to delineate their potential roles in biofilm dynamics, as well as their interactions with putative bacterial periodontopathogens and eukaryotic cells. The findings suggest that potential novel periodontal therapies targeting or utilizing the oral virome can alleviate certain clinical presentations of periodontitis. Perhaps it is time to embrace the viral dark matter within the periodontal environment to fully comprehend the pathogenesis and systemic implications of periodontitis.

Hippo signaling effectors YAP and TAZ induce Epstein-Barr Virus (EBV) lytic reactivation through TEADs in epithelial cells

The Epstein-Barr virus (EBV) human herpesvirus is associated with B-cell and epithelial-cell malignancies, and both the latent and lytic forms of viral infection contribute to the development of EBV-associated tumors. Here we show that the Hippo signaling effectors, YAP and TAZ, promote lytic EBV reactivation in epithelial cells. The transcriptional co-activators YAP/TAZ (which are inhibited by Hippo signaling) interact with DNA-binding proteins, particularly TEADs, to induce transcription. We demonstrate that depletion of either YAP or TAZ inhibits the ability of phorbol ester (TPA) treatment, cellular differentiation or the EBV BRLF1 immediate-early (IE) protein to induce lytic EBV reactivation in oral keratinocytes, and show that over-expression of constitutively active forms of YAP and TAZ reactivate lytic EBV infection in conjunction with TEAD family members. Mechanistically, we find that YAP and TAZ interact with, and activate, the EBV BZLF1 immediate-early promoter. Furthermore, we demonstrate that YAP, TAZ, and TEAD family members are expressed at much higher levels in epithelial cell lines in comparison to B-cell lines, and find that EBV infection of oral keratinocytes increases the level of activated (dephosphorylated) YAP and TAZ. Finally, we have discovered that lysophosphatidic acid (LPA), a known YAP/TAZ activator that plays an important role in inflammation, induces EBV lytic reactivation in epithelial cells through a YAP/TAZ dependent mechanism. Together these results establish that YAP/TAZ are powerful inducers of the lytic form of EBV infection and suggest that the ability of EBV to enter latency in B cells at least partially reflects the extremely low levels of YAP/TAZ and TEADs in this cell type.

The Role of Coinfections in the EBV-Host Broken Equilibrium

The Epstein–Barr virus (EBV) is a well-adapted human virus, and its infection is exclusive to our species, generally beginning in the childhood and then persisting throughout the life of most of the affected adults. Although this infection generally remains asymptomatic, EBV can trigger life-threatening conditions under unclear circumstances. The EBV lifecycle is characterized by interactions with other viruses or bacteria, which increases the probability of awakening its pathobiont capacity. For instance, EBV infects B cells with the potential to alter the germinal center reaction (GCR)—an adaptive immune structure wherein mutagenic-driven processes take place. HIV- and Plasmodium falciparum-induced B cell hyperactivation also feeds the GCR. These agents, along with the B cell tropic KSHV, converge in the ontogeny of germinal center (GC) or post-GC lymphomas. EBV oral transmission facilitates interactions with local bacteria and HPV, thereby increasing the risk of periodontal diseases and head and neck carcinomas. It is less clear as to how EBV is localized in the stomach, but together with Helicobacter pylori, they are known to be responsible for gastric cancer. Perhaps this mechanism is reminiscent of the local inflammation that attracts different herpesviruses and enhances graft damage and chances of rejection in transplanted patients. In this review, we discussed the existing evidence suggestive of EBV possessing the potential to synergize or cooperate with these agents to trigger or worsen the disease.

Epstein-Barr virus may contribute to the pathogenesis of adult-onset recurrent respiratory papillomatosis: A preliminary study

OBJECTIVE

Human papillomavirus (HPV) causes adult-onset recurrent respiratory papillomatosis (AORRP), but AORPP prevalence is much lower than HPV prevalence. Thus, HPV infection is necessary, but not sufficient, to cause AORRP and other factors likely contribute to its pathogenesis. The present study aimed to investigate whether co-infection with herpetic viruses may contribute to the pathogenesis of AORRP.

DESIGN

Prospective case-control study conducted from January 2018 to November 2019.

SETTINGS

Tertiary referral centre.

PARTICIPANTS

Eighteen consecutive patients with AORRP and 18 adults with healthy laryngeal mucosa (control group) undergoing surgery.

MAIN OUTCOME MEASURES

Cytomegalovirus, Epstein-Barr virus (EBV), herpes simplex viruses 1 and 2, human herpesvirus 6, varicella zoster virus and HPV (including genotyping) were detected in biopsies of papilloma or healthy mucosa using real-time polymerase chain reaction and reverse line blot. Dysplasia and Ki67 levels were determined in papilloma specimens.

RESULTS

EBV was present in 6 (33.3%) AORRP patients and no control patients (P = .019). Presence was not dependent on tobacco exposure (P = .413) or HPV genotype or concentration (P > .999). EBV presence was strongly related to increased cell proliferation (P = .005) and number of previous surgeries (P = .039), but not dysplasia (P > .999). Human herpesvirus 6 was found in 3 (16.7%) AORRP biopsies, with one false positive. No other herpetic virus was found.

CONCLUSIONS

Unlike other herpetic viruses, EBV seems to interact with HPV, enhancing cell proliferation and contributing to the pathogenesis and progression of AORRP. Further research is required to elucidate specific interactions and their role in the pathogenesis of AORRP.

Detection of Epstein-Barr Virus in Periodontitis: A Review of Methodological Approaches

Periodontitis, an inflammatory condition that affects the structures surrounding the tooth eventually leading to tooth loss, is one of the two biggest threats to oral health. Beyond oral health, it is associated with systemic diseases and even with cancer risk. Obviously, periodontitis represents a major global health problem with significant social and economic impact. Recently, a new paradigm was proposed in the etiopathogenesis of periodontitis involving a herpesviral–bacterial combination to promote long-term chronic inflammatory disease. Periodontitis as a risk factor for other systemic diseases can also be better explained based on viral–bacterial etiology. Significant efforts have brought numerous advances in revealing the links between periodontitis and Epstein–Barr virus (EBV), a gamma herpesvirus ubiquitous in the adult human population. The strong evidence from these studies may contribute to the advancement of periodontitis research and the ultimate control of the disease. Advancing the periodontitis research will require implementing suitable methods to establish EBV involvement in periodontitis. This review evaluates and summarizes the existing methods that allow the detection and diagnosis of EBV in periodontitis (also applicable in a more general way to other EBV-related diseases), and discusses the feasibility of the application of innovative emerging technologies.

Butyric Acid in Saliva of Chronic Periodontitis Patients Induces Transcription of the EBV Lytic Switch Activator BZLF1: A Pilot Study

BACKGROUND/AIM

Epstein-Barr virus (EBV) associates with human chronic periodontitis (CP) progression. We previously demonstrated that butyric acid (BA), produced by periodontopathic bacteria, induced EBV lytic switch activator BZLF1 expression. We investigated whether short chain fatty acids (SCFAs) in CP patients' saliva enabled EBV reactivation.

MATERIALS AND METHODS

Saliva was collected from seven CP patients and five periodontally healthy individuals. SCFAs were quantified using HPLC. BZLF1 mRNA and its pertinent protein ZEBRA were determined with Real-time PCR and western blotting. Histone H3 acetylation (AcH3) was further examined.

RESULTS

BZLF1 mRNA expression and transcriptional activity in EBV-infected Daudi cells were induced only when treated with the CP saliva. Among SCFAs, BA alone correlated significantly with the BZLF1 transcription (r=0.88; p<0.02). As expected, CP patients' saliva induced AcH3.

CONCLUSION

BA in saliva may play a role in EBV reactivation and hence contribute to EBV-related disease progression in CP patients.

Prevalence of herpesviruses in periodontal disease of the North Indian population: A pilot study

Introduction:

Periodontitis is a multifactorial disease of diverse microbiome, predominantly bacterial. Bacterial infection alone may not explain complete pathophysiology and clinical variations in disease pattern. Concept of herpesviruses playing a significant role in periodontal pathogenesis has been explored globally. Studies show varied results and difference may be accounted to variations existing in studied populations. The present study explored the prevalence of herpesviruses in periodontal disease of the North Indian population.

Materials and Methods:

In this case–control study, tissue samples were collected from the normal gingiva (control: n = 48) and deepest pocket (cases: n = 48) using a single curette stroke. Periodontal disease status was assessed through the gingival index, pocket depth, and clinical attachment level which were compared to viral marker positivity.

Results:

Ninety samples from 48 healthy gingiva and 48 periodontitis patients were assessed between the age range of 17–60 years. The prevalence of cytomegalovirus was 2.083% (cases) and 2.083% (controls) and Epstein–Barr virus (EBV) was 18.75% (cases) and 0% (controls). Odd's ratio for EBV in patients with periodontitis is calculated (Haldane–Anscombe correction) to be 21.82%. Herpes simplex virus 1/2 and varicella-zoster virus were absent in both groups.

Conclusions:

Within the limitation of this study, EBV was found in cases of periodontitis patients. Its role in disease initiation and progression is not clear. Further studies are required to ascertain EBV as risk factor in periodontal disease.

EBV LMP1 in Gingival Epithelium Potentially Contributes to Human Chronic Periodontitis via Inducible IL8 Production

BACKGROUND/AIM

Human chronic periodontitis is a major health problem. Although some oral bacteria have been reported to be putative pathogens, Epstein-Barr virus (EBV) is reported to be associated with the progression of periodontitis. However, the role of EBV in the aetiology of periodontitis is unknown. Therefore, we investigated periodontal pathogenesis of EBV to confirm whether EBV-encoded latent membrane protein 1 (LMP1) induces Interleukin-8 (IL8) production in human gingival cells.

MATERIALS AND METHODS

Real-time polymerase chain reaction, luciferase assay, enzyme-linked immunosorbent assay (ELISA), and western blotting were performed for determining IL8 mRNA expression, nuclear factor kappa B (NF-ĸB) transcription, IL8 production, and the phosphorylation of NF-ĸB p65 and Inhibitor of kappa B alpha (IĸBα), respectively, in Ca9-22 human gingival epithelial cells. Two LMP1 mutants lacking C-terminal activating region (CATR) domains responsible for activating NF-ĸB were used.

RESULTS

Extremely high IL8 production was induced by LMP1 in time- and dose-dependent manner, where simultaneous phosphorylation of NF-κB p65 and IĸBα and transcription of NF-ĸB were observed. On the contrary, IL8 production and NF-ĸB transcription were drastically inhibited by dominant negative mutant of IĸBα. Moreover, the LMP1 mutants failed to induce IL8 production.

CONCLUSION

Our findings suggest that due to CATR domains, LMP1 contributes to the progression of periodontitis via IL8 production attributable to NF-ĸB activation.

How Does Epstein-Barr Virus Contribute to Chronic Periodontitis?

Chronic periodontitis is spreading worldwide and mutually interacts with systemic diseases like diabetes mellitus. Although periodontopathic bacteria are inevitable pathogens in their onset and progression, many cases are not ascribable to the virulence of these bacteria because the effect of plaque control is limited. In contrast, Epstein-Barr virus (EBV) in the periodontium has been correlated with chronic periodontitis and has recently been considered as a promising pathogenic candidate for this disease. However, several important questions have yet to be addressed. For instance, although EBV latently infects more than 90% of individuals over the world, why do patients with chronic periodontitis exclusively harbor progeny EBV in the oral cavity? In addition, how does latently infected or reactivated EBV in the periodontium relate to the onset or progression of chronic periodontitis? Finally, is periodontitis incurable because EBV is the pathogen for chronic periodontitis? In this review, we attempt to answer these questions by reporting the current understanding of molecular relations and mechanisms between periodontopathic bacteria and EBV reactivation in the context of how this relationship may pertain to the etiology of chronic periodontitis.

Epstein-Barr virus-infected plasma cells in periodontitis lesions

Growing evidence supports that the Epstein-Barr virus (EBV) is a putative periodontal pathogen, but little is known regarding EBV behavior in periodontitis. Here, EBV infection was monitored in saliva and periodontal pocket (PP), at baseline and 3 months after periodontal non-surgical therapy (p-NST) in 20 patients diagnosed with periodontitis. After the treatment, the patients with the improved periodontal condition (good responders) showed a significant decrease in salivary EBV load. In contrast, in poor responders, EBV load was slightly increased. Moreover, after the therapy, most patients showed clear signs of EBV infection in a deep PP (≥5 mm) selected as a study site. To investigate how EBV can persist in a PP, we further investigate cellular sites of viral replication in PP. We identified large amounts of infiltrated EBV-infected cells, mostly overlapping with CD138⁺ plasma cells (PC). EBV-infected PCs formed high-density clusters within the infiltrate and along the periodontal epithelium which were commonly associated with CD3⁺ T-cells and CD20⁺ B-cells to evoke diffuse ectopic lymphoid-like structures. Taking together, this study provides new insights to support a model where the periodontal condition may play a major role in oral EBV shedding. Since PC harbors the late productive phases of EBV replication, the periodontal condition may favor B-cell differentiation with possible amplification of periodontal EBV infection and viral spreading. PCs have long been recognized as pathogenic markers in inflammatory lesions. Our finding sheds new light on the role of EBV infection and PC in periodontitis.

Periodontal herpesvirus morbidity and treatment

Four billion individuals worldwide have a history of periodontitis, with the poorest people in society most affected. Periodontitis can lead to unsightly drifting of teeth and tooth loss that may interfere with the wellbeing of daily living and has also been linked to at least 57 medical diseases and disabilities. The etiology of severe periodontitis includes active herpesviruses, specific bacterial pathogens, and destructive immune responses, but herpesviruses seem to be the major pathogenic determinant. Periodontal herpesviruses that disseminate via the systemic circulation to nonoral sites may represent a major link between periodontitis and systemic diseases. Current treatment of periodontitis focuses almost exclusively on bacterial biofilm and will require revision. Periodontal therapy that targets both herpesviruses and bacterial pathogens can provide long-term clinical improvement and potentially reduces the risk of systemic diseases. Molecular diagnostic tests for periodontal pathogens may enable early microbial identification and preemptive therapy. This review details an efficient and reliable anti-infective treatment of severe periodontitis that can be carried out in minimal time with minimal cost.

New Viral Facets in Oral Diseases: The EBV Paradox

The oral cavity contributes to overall health, psychosocial well-being and quality of human life. Oral inflammatory diseases represent a major global health problem with significant social and economic impact. The development of effective therapies, therefore, requires deeper insights into the etiopathogenesis of oral diseases. Epstein–Barr virus (EBV) infection results in a life-long persistence of the virus in the host and has been associated with numerous oral inflammatory diseases including oral lichen planus (OLP), periodontal disease and Sjogren’s syndrome (SS). There is considerable evidence that the EBV infection is a strong risk factor for the development and progression of these conditions, but is EBV a true pathogen? This long-standing EBV paradox yet needs to be solved. This review discusses novel viral aspects of the etiopathogenesis of non-tumorigenic diseases in the oral cavity, in particular, the contribution of EBV in OLP, periodontitis and SS, the tropism of EBV infection, the major players involved in the etiopathogenic mechanisms and emerging contribution of EBV-pathogenic bacteria bidirectional interaction. It also proposes the involvement of EBV-infected plasma cells in the development and progression of oral inflammatory diseases. A new direction for preventing and treating these conditions may focus on controlling pathogenic EBV with anti-herpetic drugs.

The Spectrum of EBV-Positive Mucocutaneous Ulcer: A Study of 9 Cases

We describe a series of 9 patients with Epstein-Barr virus (EBV)-positive mucocutaneous lymphoproliferative lesions that broadens the concept of EBV-positive mucocutaneous ulcer. We report 5 female and 4 male patients, with an average age of 74 years (range, 55 to 87 y), 2 of whom were HIV-positive. The lesions were located in the oropharynx, skin, and rectal and/or genital mucosa. Histopathologically, 6 cases showed a polymorphic pattern and 3 had a monomorphic and diffuse one, with angiotropism in 4 cases (2 each with the polymorphic and monomorphic patterns). Three of the cases expressed PDL1. In addition to its presence in the neoplastic lymphoid cells, EBV was also detected in adjacent epithelial cells in an oropharyngeal lesion. All cases responded to local therapy or adapted systemic chemotherapy in selected cases. This series extends the spectrum of this disorder to include some HIV-positive cases, patients with multiple lesions confined to a single anatomic area, lesions with an angiocentric pattern, and some cases with monomorphous large-cell cytology. We discuss the differential clinicopathologic diagnosis of this disorder and that of classic EBV large B-cell lymphoma.

Detection of Virus Herpes Simplex Type 1 in Patients with Chronic Periodontal Disease

BACKGROUND

Periodontal disease is an inflammatory-destructive condition of the supporting tissues of the teeth. Microorganisms found in the dental plaque were considered to be the primary local etiologic factor responsible for the periodontal destruction. It is also evident that herpes simplex viruses may have an impact in the etiopathogenesis of periodontal disease.

AIM

This study has been made with the aim to analyse the prevalence of herpes simplex virus type 1 (HSV-1) in the dental plaque (supra- and subgingival) of patients with the chronic periodontal disease.

MATERIAL AND METHODS

The study comprised a total of 89 patients with chronic periodontal disease divided into two groups (patients with moderate and severe periodontitis). Supragingival dental plaque samples were taken with sterile cotton (supragingival), and subgingival dental plaque samples were taken with paper absorbents. Samples were subjected to extraction of DNA and further analysis with multiplex PCR for the presence of herpes viral DNA.

RESULTS

HSV-1 virus was detected In 24.7% of all patients included in the study. HSV-1 was detected in 22.2% of patients with the moderate stage of the disease, of which in all (100%) in the supragingival plaque samples and only 16.7% in subgingival plaque samples. In two patients HSV-1 was concomitantly detected in supra and subgingival plaque samples. In patients with advanced stage of the disease, the HSV-1 virus was detected in 28.6% patients. In two of the patients, HSV-1 was concomitantly detected in supra and subgingival plaque samples. Statistically, a significant difference was found in HSV-1 positive patients with a moderate stage of disease, between the presence of the virus in subgingival (100%) and subgingival (16.7%) dental plaque samples, p < 0.05.

CONCLUSION

Herpes simplex viruses type 1 are present in supragingival and subgingival dental plaque.

Age-related changes in immune function (immune senescence) in caries and periodontal diseases: a systematic review

AIM

To systematically review the evidence regarding immune senescence in the pathogenesis of periodontitis and dental caries.

METHODS

A systematic search of electronic databases utilizing medical subject headings (MeSH terms) supplemented by screening of review articles and other relevant texts was undertaken.

RESULTS

Seventy-three articles were included (43 for periodontitis, 30 for caries). Study results were found to be generally heterogeneous. Regarding periodontitis, human studies suggest evidence for altered neutrophil function and increased production of pro-inflammatory mediators (e.g. interleukin-1β, interleukin-6 and prostaglandin E₂ ) in older compared to younger subjects, and animal experiments suggest increased expression of genes that contribute to a pro-inflammatory state in older compared to younger animals. Regarding dental caries, research relating to changes in immune functioning and the impact of ageing is in its infancy. A small number of studies have reported components of innate and adaptive immunity that affect the composition of saliva and dental biofilms with possible impacts on caries progression.

CONCLUSION

There is evidence that immune functioning related to periodontitis and (less investigated) dental caries alters with increasing age. In both conditions, age-associated mechanistic changes in immune functioning are complex and incompletely understood and it is not clear how these relate to disease susceptibility.

Epstein-Barr Virus–Infected Plasma Cells Infiltrate Erosive Oral Lichen Planus

Epstein-Barr virus (EBV), in addition to its transforming properties, contributes to the pathogenesis of several inflammatory diseases. Here, we investigated its involvement in oral lichen planus (OLP), a common autoimmune-like disease of unknown etiopathogenesis that can display a malignant potential. EBV-infected cells (EBV+ cells) were sought in a large series of clinically representative OLPs ( n = 99) through in situ hybridization to detect small noncoding EBV-encoded RNAs. Overall, our results demonstrated that EBV was commonly found in OLP (74%), with significantly higher frequency (83%) in the erosive form than in the reticular/keratinized type mild form (58%). Strikingly, many erosive OLPs were massively infiltrated by large numbers of EBV+ cells, which could represent a large part of the inflammatory infiltrate. Moreover, the number of EBV+ cells in each OLP section significantly correlated with local inflammatory parameters (OLP activity, infiltrate depth, infiltrate density), suggesting a direct relationship between EBV infection and inflammatory status. Finally, we characterized the nature of the infiltrated EBV+ cells by performing detailed immunohistochemistry profiles ( n = 21). Surprisingly, nearly all EBV+ cells detected in OLP lesions were CD138+ plasma cells (PCs) and more rarely CD20+ B cells. The presence of EBV+ PCs in erosive OLP was associated with profound changes in cytokine expression profile; notably, the expression of key inflammatory factors, such as IL1-β and IL8, were specifically increased in OLP heavily infiltrated with EBV+ PCs. Moreover, electron microscopy–based experiments showed that EBV+ PCs actively produced EBV viral particles, suggesting possible amplification of EBV infection within the lesion. Our study thus brings conclusive evidence showing that OLP is commonly infiltrated with EBV+ PCs, adding a further puzzling element to OLP pathogenesis, given that PCs are now considered to be major regulatory immune cells involved in several autoimmune diseases (ClinicalTrials.gov NCT02276573).

Herpesvirus-encoded microRNAs detected in human gingiva alter host cell transcriptome and regulate viral infection

MicroRNAs (miRNAs) are small, non-coding RNAs of ~18-25 nucleotides that have gained extensive attention as critical regulators in complex gene networks including immune cell lineage commitment, differentiation, maturation, and maintenance of immune homeostasis and function. Many viruses encode miRNAs that directly downregulate the expression of factors of the innate immune system, which includes proteins involved in promoting apoptosis and recruitment. In this study, we examined the expression profiles of three previously identified viral miRNAs (v-miRs) from the human herpesvirus (HHV) family, HSV-1 (miR-H1), KSHV (miR-K12-3-3p), and HCMV (miR-US4) in healthy and diseased periodontal tissues and observed increased levels of v-miRs in diseased tissues. To understand the significance of this increase, we overexpressed v-miRs in human oral keratinocytes (HOK), a common target for various HHV, and analyzed the impact of miR-H1 and miR-K12-3-3p on the host transcriptome. More than 1300 genes were altered in HOK overexpressing miR-H1 and miR-K12-3-3p. Global pathway analysis of deregulated genes identified several key cellular pathways that may favor viral persistence. Using bioinformatic analysis, we predicted hundreds of potential v-miR binding sites on genes downregulated by miR-H1 and miR-K12-3-3p and validated three novel target v-miR sites suggesting widespread direct and indirect modulation of numerous host genes/pathways by a single v-miR. Finally, in vitro HSV-1 infection assays showed that miR-H1 can regulate viral entry and infection in human oral keratinocytes (HOK). Overall, our results demonstrate clinical and functional relevance of pathogenic viral molecules viz., v-miRs that regulate both host and viral functions and may contribute to the pathogenesis of inflammatory oral diseases.

Viral miRNAs Alter Host Cell miRNA Profiles and Modulate Innate Immune Responses

Prevalence of the members of herpesvirus family in oral inflammatory diseases is increasingly acknowledged suggesting their likely role as an etiological factor. However, the underlying mechanisms remain obscure. In our recent miRNA profiling of healthy and diseased human tooth pulps, elevated expression of human herpesvirus encoded viral microRNAs (v-miRs) were identified. Based on the fold induction and significance values, we selected three v-miRs namely miR-K12-3-3p [Kaposi sarcoma-associated virus (KSHV)], miR-H1 [herpes simplex virus 1 (HSV1)], and miR-UL-70-3p [human cytomegalovirus (HCMV)] to further examine their impact on host cellular functions. We examined their impact on cellular miRNA profiles of primary human oral keratinocytes (HOK). Our results show differential expression of several host miRNAs in v-miR-transfected HOK. High levels of v-miRs were detected in exosomes derived from v-miR transfected HOK as well as the KSHV-infected cell lines. We show that HOK-derived exosomes release their contents into macrophages (Mφ) and alter expression of endogenous miRNAs. Concurrent expression analysis of precursor (pre)-miRNA and mature miRNA suggest transcriptional or posttranscriptional impact of v-miRs on the cellular miRNAs. Employing bioinformatics, we predicted several pathways targeted by deregulated cellular miRNAs that include cytoskeletal organization, endocytosis, and cellular signaling. We validated three novel targets of miR-K12-3-3p and miR-H1 that are involved in endocytic and intracellular trafficking pathways. To evaluate the functional consequence of this regulation, we performed phagocytic uptake of labeled bacteria and noticed significant attenuation in miR-H1 and miR-K12-3-3p but not miR-UL70-3p transfected primary human Mφ. Multiple cytokine analysis of E. coli challenged Mφ revealed marked reduction of secreted cytokine levels with important roles in innate and adaptive immune responses suggesting a role of v-miRs in immune subversion. Our findings reveal that oral disease associated v-miRs can dysregulate functions of key host cells that shape oral mucosal immunity thus exacerbating disease severity and progression.

Prevalence of Epstein-Barr virus DNA and Porphyromonas gingivalis in Japanese peri-implantitis patients

Background

Peri-implantitis (PI) is an inflammatory reaction associated with functional deterioration of supporting bones around the dental implant. Recent studies suggested Epstein–Barr virus (EBV) is involved in the pathogenesis of periodontitis. We investigated the association between EBV and Porphyromonas gingivalis in Japanese PI patients.

Methods

Fifteen periodontally healthy individuals, 15 healthy implant patients and 15 PI patients were recruited. Forty five subgingival plaque samples were collected from the deepest probing pocket depth (PPD) site from each patient. Real-time PCR was used to detect EBV DNA and P. gingivalis.

Results

EBV and P. gingivalis were detected in 7 and 3 PPD sites of the healthy controls, in 9 and 4 PPD sites of the healthy implants, and in 13 and 14 PPD sites of the PI patients. P. gingivalis and coexistence of EBV and P. gingivalis were detected significantly higher in the PI patients than healthy controls and healthy implant patients. EBV was detected significantly higher in the PI patients than healthy controls.

Conclusions

Higher levels of EBV and P. gingivalis were detected in PPD sites of PI patients. These results suggest that coexistence of EBV and P. gingivalis may serve pathogenic factors cause for PI in Japanese dental patients.

Identification of Epstein-Barr Virus in the Human Placenta and Its Pathologic Characteristics

Epstein-Barr virus (EBV), a common pathogen in humans, is suspected as the cause of multiple pregnancy-related pathologies including depression, preeclampsia, and stillbirth. Moreover, transmission of EBV through the placenta has been reported. However, the focus of EBV infection within the placenta has remained unknown to date. In this study, we proved the expression of latent EBV genes in the endometrial glandular epithelial cells of the placenta and investigated the cytological characteristics of these cells. Sixty-eight placentas were obtained from pregnant women. Tissue microarray was constructed. EBV latent genes including EBV-encoding RNA-1 (EBER1), Epstein-Barr virus nuclear antigen 1 (EBNA1), late membrane antigen (LMP1), and RPMS1 were detected with silver in situ hybridization and/or mRNA in situ hybridization. Nuclear features of EBV-positive cells in EBV-infected placenta were compared with those of EBV-negative cells via image analysis. Sixteen placentas (23.5%) showed positive expression of all 4 EBV latent genes; only the glandular epithelial cells of the decidua showed EBV gene expression. EBV infection status was not significantly correlated with maternal, fetal, or placental factors. The nuclei of EBV-positive cells were significantly larger, longer, and round-shaped than those of EBV-negative cells regardless of EBV-infection status of the placenta. For the first time, evidence of EBV gene expression has been shown in placental tissues. Furthermore, we have characterized its cytological features, allowing screening of EBV infection through microscopic examination.

Evaluation of microbiota associated with Herpesviruses in active sites of generalized aggressive periodontitis

Aims

The present study aimed to investigate microbial patterns associated with disease progression and coinfection by different Herpesviruses in generalized aggressive periodontitis (GAP).

Methods

Microbiological samples were obtained from active (AS) and non-active (n-AS) sites in 165 subjects affected by GAP and were analyzed for 40 bacterial species by the Checkerboard DNA-DNA Hybridization technique and for Herpes simplex 1 (HSV-1), Human Cytomegalovirus (CMV), and Epstein Bar virus (EBV) by PCR.Common Factor Analysis and Multiple Regression Analysis were applied to disclose specific microbial patterns associated with the three viruses.

Results

Herpesviruses were detected in 37.6% of subjects. Detection of each of the searched viruses was associated with specific patterns of subgingival biofilm in AS. Logistic regression analyses evidenced several virus/bacteria associations: i) EBV with Aggregatibacter actinomycetemcomitans; ii) CMV with A. actinomycetemcomitans, Veillonella parvula, Parvimonas micra and Fusobacterium nucleatum subsp. polymorphum; iii) HSV-1 with Porphyromonas gingivalis, Tannerella forsythia, Fusobacterium periodonticum and Staphylococcus aureus.

Conclusions

Microbiological data suggest that Herpesviruses are probably not mere spectators of disease progression and that specific patterns of subgingival plaque are correlated with the presence of different Herpesviruses.

Epstein-Barr virus is associated with periodontal diseases: A meta-analysis based on 21 case-control studies

Some controversies still exist between the detection of Epstein-Barr virus (EBV)'s DNA and risks of periodontal diseases. Hence, a comprehensive meta-analysis on all available literatures was performed to clarify the relationship between EBV and preidontitis.A comprehensive search was conducted within the PUBMED, EMBASE, and WANFANG databases up to October 10th, 2016 according to inclusion and exclusion criteria and finally 21 case-control literatures were obtained. The outcomes including odds ratios (ORs) with 95% confidence intervals (CIs) were used to assess the strength of associations. Publication bias was determined by Begg or Egger test. Sensitivity analysis was used to investigate reliability and stability of the results.According to the data from included trials, the association between overall increased risks of periodontitis and the detection of EBV was significant (OR = 6.199, 95% CI = 3.119-12.319, P < 0.001). In the disease-type analysis, the pooled ORs for chronic periodontitis and aggressive periodontitis were 6.586 (95% CI = 3.042-14.262, P < 0.001) and 8.361 (95% CI = 2.109-33.143, P = 0.003), respectively. In the subgroup analysis of ethnicity, our results suggested that high EBV-detecting frequencies were correlated with increased risks of periodontitis in Asians, Europeans, and Americans (P < 0.001). Subgroup analysis by the sample type showed that subgingival plaque (SgP) samples and tissue samples were available for EBV detecting (P < 0.001). Detecting EBV of samples in ≥5 (6) mm sites of periodontal pockets were easier than in ≤3-mm sites (P = 0.023).This meta-analysis indicates that high frequent detection of EBV correlates with increased risk of periodontal diseases. SgP and tissue are available for detecting EBV in patients of periodontitis. At last, our results suggest that detecting EBV of samples in =5 (6) mm sites of periodontal pockets are more sensitive than in ≤3-mm sites.

Programmed cell death in periodontitis: recent advances and future perspectives

Periodontitis is a highly prevalent infectious disease, characterized by destruction of the periodontium, and is the main cause of tooth loss. Periodontitis is initiated by periodontal pathogens, while other risk factors including smoking, stress, and systemic diseases aggravate its progression. Periodontitis affects many people worldwide, but the molecular mechanisms by which pathogens and risk factors destroy the periodontium are unclear. Programmed cell death (PCD), different from necrosis, is an active cell death mediated by a cascade of gene expression events and can be mainly classified into apoptosis, autophagy, necroptosis, and pyroptosis. Although PCD is involved in many inflammatory diseases, its correlation with periodontitis is unclear. After reviewing the relevant published articles, we found that apoptosis has indeed been reported to play a role in periodontitis. However, the role of autophagy in periodontitis needs further verification. Additionally, implication of necroptosis or pyroptosis in periodontitis remains unknown. Therefore, we recommend future studies, which will unravel the pivotal role of PCD in periodontitis, allowing us to prevent, diagnose, and treat the disease, as well as predict its outcomes.

Human papillomavirus promotes Epstein-Barr virus maintenance and lytic reactivation in immortalized oral keratinocytes

Epstein-Barr virus and human papillomaviruses are human tumor viruses that infect and replicate in upper aerodigestive tract epithelia and cause head and neck cancers. The productive phases of both viruses are tied to stratified epithelia highlighting the possibility that these viruses may affect each other's life cycles. Our lab has established an in vitro model system to test the effects of EBV and HPV co-infection in stratified squamous oral epithelial cells. Our results indicate that HPV increases maintenance of the EBV genome in the co-infected cells and promotes lytic reactivation of EBV in upper layers of stratified epithelium. Expression of the HPV oncogenes E6 and E7 were found to be necessary and sufficient to account for HPV-mediated lytic reactivation of EBV. Our findings indicate that HPV increases the capacity of epithelial cells to support the EBV life cycle, which could in turn increase EBV-mediated pathogenesis in the oral cavity.

The BDLF3 gene product of Epstein-Barr virus, gp150, mediates non-productive binding to heparan sulfate on epithelial cells and only the binding domain of CD21 is required for infection

The cell surface molecules used by Epstein-Barr virus (EBV) to attach to epithelial cells are not well-defined, although when CD21, the B cell receptor for EBV is expressed epithelial cell infection increases disproportionately to the increase in virus bound. Many herpesviruses use low affinity charge interactions with molecules such as heparan sulfate to attach to cells. We report here that the EBV glycoprotein gp150 binds to heparan sulfate proteoglycans, but that attachment via this glycoprotein is not productive of infection. We also report that only the aminoterminal two short consensus repeats of CD21 are required for efficient infection, This supports the hypothesis that, when expressed on an epithelial cell CD21 serves primarily to cluster the major attachment protein gp350 in the virus membrane and enhance access of other important glycoproteins to the epithelial cell surface.

Systemic antibiotics and the risk of superinfection in peri-implantitis

Peri-implantitis has emerged in the last few years as a complication difficult to resolve. The etiopathogenesis consensus is mainly attributed to bacteria. Following the preferred reporting items for systematic reviews and meta-analysis (PRISMA) guidelines, a PubMed/Medline literature search was performed using the US National Library of Medicine database up to 2015 to analyze available scientific data on the rationale and risk of superinfection associated to systemic antimicrobials in human peri-implant disease. A hand search was also conducted on relevant medical and microbiology journals. The methodological index for non-randomized studies (MINORS) was independently assessed for quality on the selected papers. Proposed combined therapies use broad-spectrum antibiotics to halt the disease progression. A major associated risk, particularly when prescribed empirically without microbiological follow-up, is the undetected development of superinfections and overgrowth of opportunistic pathogens difficult to eradicate. Peri-implant superinfections with opportunistic bacteria, yeast and viruses, are plausible risks associated to the use of systemic antibiotics in immunocompetent individuals. Lack of microbiological follow-up and antibiotic susceptibility testing may lead to ongoing microbial challenges that exacerbate the disease progression. The increased proliferation of antimicrobial resistance, modern implant surface topography and indiscriminative empiric antibiotic regimens may promote the escalation of peri-implant disease in years to come. A personalized 3-month supportive therapy may help prevent risks by sustaining a normal ecological balance, decreasing specific pathogen proportions and maintaining ideal plaque control.

Are herpes virus associated to aggressive periodontitis? A review of literature

Periodontal Disease includes a wide variety of infectious entities with various clinical manifestations in the oral cavity and responses to treatment. The determinants of clinical manifestations of periodontal disease include the type of infectious agent, the host immune response and environmental factors. Aggressive periodontitis (AP) is defined as a type of inflammation with specific clinical and laboratory features, which distinguish it from other types of periodontitis, with high incidence rates in a sub-group of individuals. Bacteria have been frequently mentioned as the agent inciting gingival inflammation and tissue destruction that underlies the pathogenesis of periodontitis. However, recent studies, with some controversial results, have suggested that the herpes family of viruses, including CMV and EBV-1 as well as papillomaviruses, HIV, Human T-lymphotropic virus type 1, Torquetenovirus and hepatitis B and C occur with high frequency in active periodontal lesions. There is a lack of information about this disease and the role of herpesviruses in its pathophysiology. This review provides a critical analysis of the scientific evidence linking bacteria and viruses with AP and their potential impact on clinical characteristics, prognosis and therapy.

Emerging and changing viral diseases in the new millennium

Most viral infections encountered in resource‐rich countries are relatively trivial and transient with perhaps fever, malaise, myalgia, rash (exanthema) and sometimes mucosal manifestations (enanthema), including oral in some. However, the apparent benignity may be illusory as some viral infections have unexpected consequences – such as the oncogenicity of some herpesviruses and human papillomaviruses. Infections are transmitted from various human or animal vectors, especially by close proximity, and the increasing movements of peoples across the globe, mean that infections hitherto confined largely to the tropics now appear worldwide. Global warming also increases the range of movement of vectors such as mosquitoes. Thus recent decades have seen a most dramatic change with the emergence globally also of new viral infections – notably human immunodeficiency viruses (HIV) – and the appearance of some other dangerous and sometimes lethal infections formerly seen mainly in, and reported from, resource‐poor areas especially in parts of Asia, Latin America and Africa. This study offers a brief update of the most salient new aspects of the important viral infections, especially those with known orofacial manifestations or other implications for oral health care.

Chemokine function in periodontal disease and oral cavity cancer

The chemotactic cytokines, or chemokines, comprise a superfamily of polypeptides with a wide range of activities that include recruitment of immune cells to sites of infection and inflammation, as well as stimulation of cell proliferation. As such, they function as antimicrobial molecules and play a central role in host defenses against pathogen challenge. However, their ability to recruit leukocytes and potentiate or prolong the inflammatory response may have profound implications for the progression of oral diseases such as chronic periodontitis, where tissue destruction may be widespread. Moreover, it is increasingly recognized that chronic inflammation is a key component of tumor progression. Interaction between cancer cells and their microenvironment is mediated in large part by secreted factors such as chemokines, and serves to enhance the malignant phenotype in oral and other cancers. In this article, we will outline the biological and biochemical mechanisms of chemokine action in host–microbiome interactions in periodontal disease and in oral cancer, and how these may overlap and contribute to pathogenesis.

Prevalence and quantitative analysis of Epstein-Barr virus DNA and Porphyromonas gingivalis associated with Japanese chronic periodontitis patients

Objective

A number of studies have recently suggested Epstein–Barr virus (EBV) involvement in the pathogenesis of periodontitis. In this study, we investigated the association between major periodontopathic bacteria Porphyromonas gingivalis (P. gingivalis) and EBV in Japanese chronic periodontitis (CP) patients.

Materials and methods

A group of 25 patients with CP participated in the study along with 13 individuals without periodontitis. Subgingival samples were obtained with paper points. Quantitative real-time polymerase chain reaction (PCR) was used to detect EBV DNA and P. gingivalis.

Results

In the CP patients, EBV DNA and P. gingivalis were detected in both 80 % of sites with probing pocket depths (PPD) of ≥5 mm and in 40 and 36 % of sites with PPD ≤3 mm, respectively. EBV DNA and P. gingivalis were detected in 50 and 27 % of the sites in periodontally healthy individuals. Coexistence of EBV DNA and P. gingivalis was significantly higher in the deeper PPD sites of CP patients (68 %) than in the PPD sites of the healthy controls (15 %) and shallow PPD sites of CP patients (12 %). PCR-positive deeper PPD sites of CP patients for EBV DNA and P. gingivalis range between 3.74 × 10³∼2.83 × 10⁹ and 2.73 × 10⁵∼6.65 × 10⁹ (copies/ml), respectively.

Conclusion

These results suggest an association between EBV DNA, P. gingivalis, and CP in Japanese individuals. Further studies are required to clarify this association; however, we believe that our enhanced understanding of the pathogenesis of periodontal diseases involving viral infections will lead to new treatments.