EBV-encoded microRNAs profile evaluation in pediatric liver transplant recipients

Novel plasma microRNA expression features in diagnostic use for Epstein-Barr virus-associated febrile diseases

Background

Epstein-Barr virus (EBV) is widely infected in humans and causes various diseases. Among them, microRNAs of EBV play a key role in the progression of EBV-associated febrile diseases. There're few specific indicators for rapid differential diagnosis of various febrile diseases associated with EBV, and the lack of more reliable screening methods with high diagnostic utility has led to spaces for improvement in the accurate diagnosis and efficient treatment of relevant patients, making EBV infection a complicated clinical problem. With recent advances in plasma microRNA testing, the apparent presence of EBV microRNAs in plasma can help screen for EBV infection. The gene networks targeted by these microRNAs can also indicate potential biomarkers of EBV-associated febrile diseases. This study aimed to identify some novel miRNAs as potential biomarkers for early diagnosis of respectively EBV-associated febrile diseases.

Materials and methods

A total of 110 participants were recruited for this task. First, we performed high-throughput sequencing and preliminary PCR validation of differentially expressed miRNAs in 15 participants with EBV-associated fever (divided into common EBV carriers), infectious mononucleosis (IM) and chronic active EBV infection (CAEBV), EBV-associated Hemophagocytic Lymphohistiocytosis group (EBV-HLH), and 3 healthy individuals. After a comprehensive analysis, 10 miRNAs with abnormal expression were screened, and then qRT-PCR was performed in the rest of 95 participants to detect the validation of miRNAs expression in plasma samples. Thereafter, we further investigated their potential for clinical application in EBV-related febrile diseases by using a combination of Gene Ontology analysis, Kyoto Encyclopedia of Genes and Genomes pathway analysis, and Protein-protein interaction network analysis.

Results

Through identification and detailed analysis of the obtained data, we found significant differences in the expression of Hsa-miR-320d, EBV-miR-BART22, and EBV-miR-BART2-3p in blood samples from patients with different EBV-related febrile diseases. We found that the expression levels of Hsa-miR-320d, EBV-miR-BART22, and EBV-miR-BART2-3p in plasma are indicative of determining different disease types of EBV-related febrile diseases, while EBV-miR-BART22 and EBV-miR-BART2-3p may be potential therapeutic targets.

Conclusion

The expression levels of Hsa-miR-320d, EBV-miR-BART22, and EBV-miR-BART2-3p suggest that they may be used as transcriptional features for early differential diagnosis of EBV-related febrile diseases, and EBV-miR-BART22 and EBV-miR-BART2-3p may be potential therapeutic targets.

The IPTA Nashville Consensus Conference on Post-Transplant lymphoproliferative disorders after solid organ transplantation in children: III - Consensus guidelines for Epstein-Barr virus load and other biomarker monitoring

The International Pediatric Transplant Association convened an expert consensus conference to assess current evidence and develop recommendations for various aspects of care relating to post-transplant lymphoproliferative disorders after solid organ transplantation in children. In this report from the Viral Load and Biomarker Monitoring Working Group, we reviewed the existing literature regarding the role of Epstein-Barr viral load and other biomarkers in peripheral blood for predicting the development of PTLD, for PTLD diagnosis, and for monitoring of response to treatment. Key recommendations from the group highlighted the strong recommendation for use of the term EBV DNAemia instead of "viremia" to describe EBV DNA levels in peripheral blood as well as concerns with comparison of EBV DNAemia measurement results performed at different institutions even when tests are calibrated using the WHO international standard. The working group concluded that either whole blood or plasma could be used as matrices for EBV DNA measurement; optimal specimen type may be clinical context dependent. Whole blood testing has some advantages for surveillance to inform pre-emptive interventions while plasma testing may be preferred in the setting of clinical symptoms and treatment monitoring. However, EBV DNAemia testing alone was not recommended for PTLD diagnosis. Quantitative EBV DNAemia surveillance to identify patients at risk for PTLD and to inform pre-emptive interventions in patients who are EBV seronegative pre-transplant was recommended. In contrast, with the exception of intestinal transplant recipients or those with recent primary EBV infection prior to SOT, surveillance was not recommended in pediatric SOT recipients EBV seropositive pre-transplant. Implications of viral load kinetic parameters including peak load and viral set point on pre-emptive PTLD prevention monitoring algorithms were discussed. Use of additional markers, including measurements of EBV specific cell mediated immunity was discussed but not recommended though the importance of obtaining additional data from prospective multicenter studies was highlighted as a key research priority.

Critical review of Epstein-Barr virus microRNAs relation with EBV-associated gastric cancer

Epstein-Barr virus (EBV)-associated gastric cancer (EBVaGC) is regarded as the most prevalent malignant tumor triggered by EBV infection. In recent years, increasing attention has been considered to recognize more about the disease process's exact mechanisms. There is accumulating evidence that showing epigenetic modifications play critical roles in the EBVaGC pathogenesis. MicroRNAs (miRNAs), as critical epigenetic modulators, are single-strand short noncoding RNA (length ~ <200 bp), which regulate gene expression through binding to the 3'-untranslated region (3'-UTR) of target RNA transcripts and either degrade or repress their activities. In the latest research on EBV, it was found that this virus could encode miRNAs. Mechanistically, EBV-encoded miRNAs are involved in carcinogenesis and the progression of EBV-associated malignancies. Moreover, these miRNAs implicated in immune evasion, identification of pattern recognition receptors, regulation of lymphocyte activation and lethality, modulation of infected host cell antigen, maintain of EBV infection status, promotion of cell proliferation, invasion and migration, and reduction of apoptosis. As good news, not only has recent data demonstrated the crucial function of EBV-encoded miRNAs in the pathogenesis of EBVaGC, but it has also been revealed that aberrant expression of exosomal miRNAs in EBVaGC has made them biomarkers for detection of EBVaGC. Regarding these substantial characterizes, the critical role of EBV-encoded miRNAs has been a hot topic in research. In this review, we will focus on the multiple mechanisms involved in EBVaGC caused by EBV-encoded miRNAs and briefly discuss their potential application in the clinic as a diagnostic biomarker.

miR-4721, Induced by EBV-miR-BART22, Targets GSK3β to Enhance the Tumorigenic Capacity of NPC through the WNT/β-catenin Pathway

Nasopharyngeal carcinoma (NPC) is prevalent in East and Southeast Asia. In a previous study, Epstein-Barr virus (EBV)-miR-BART22 induces tumor metastasis and stemness and is significantly involved in NPC progression. In the present study, we observed that miR-4721 is induced by EBV-miR-BART22 through phosphatidylinositol 3-kinase (PI3K)/AKT/c-JUN/Sp1 signaling to promote its transcription. In a subsequent study, we observed that miR-4721 serves as a potential oncogenic factor promoting NPC cell cycle progression and cell proliferation in vitro and in vivo. Mechanism analysis indicated that miR-4721 directly targetes GSK3β and reduces its expression, which therefore elevates β-catenin intra-nuclear aggregation and activates its downstream cell cycle factors, including CCND1 and c-MYC. In clinical samples, miR-4721 and GSK3β are respectively observed to be upregulated and downregulated in NPC progression. Elevated expression of miR-4721 is positively associated with clinical progression and poor prognosis. Our study first demonstrated that miR-4721 as an oncogene is induced by EBV-miR-BART22 via modulating PI3K/AKT/c-JUN/Sp1 signaling to target GSK3β, which thus activates the WNT/β-catenin-stimulated cell cycle signal and enhances the tumorigenic capacity in NPC. miR-4721 may be a potential biomarker or therapeutic target in NPC treatment in the future.

Vesicle-bound EBV-BART13-3p miRNA in circulation distinguishes nasopharyngeal from other head and neck cancer and asymptomatic EBV-infections

Cell‐free microRNA (miRNA) in biofluids released by tumors in either protein or vesicle‐bound form, represent promising minimally‐invasive cancer biomarkers. However, a highly abundant non‐tumor background in human plasma and serum complicates the discovery and detection of tumor‐selective circulating miRNAs. We performed small RNA sequencing on serum and plasma RNA from Nasopharyngeal Carcinoma (NPC) patients. Collectively, Epstein Barr virus‐encoded miRNAs, more so than endogenous miRNAs, signify presence of NPC. However, RNAseq‐based EBV miRNA profiles differ between NPC patients, suggesting inter‐tumor heterogeneity or divergent secretory characteristics. We determined with sensitive qRT‐PCR assays that EBV miRNAs BART7‐3p, BART9‐3p and BART13‐3p are actively secreted by C666.1 NPC cells bound to extracellular vesicles (EVs) and soluble ribonucleoprotein complexes. Importantly, these miRNAs are expressed in all primary NPC tumor biopsies and readily detected in nasopharyngeal brushings from both early and late‐stage NPC patients. Increased levels of BART7‐3p, BART9‐3p and particularly BART13‐3p, distinguish NPC patient sera from healthy controls. Receiver operating characteristic curve analysis using sera from endemic NPC patients, other head and neck cancers and individuals with asymptomatic EBV‐infections reveals a superior diagnostic performance of EBV miRNAs over anti‐EBNA1 IgA serology and EBV‐DNA load (AUC 0.87–0.96 vs 0.86 and 0.66 respectively). The high specificity of circulating EBV‐BART13‐3p (97%) for NPC detection is in agreement with active secretion from NPC tumor cells. We conclude EV‐bound BART13‐3p in circulation is a promising, NPC‐selective, biomarker that should be considered as part of a screening strategy to identify NPC in endemic regions.

What's new?

Analysis of DNA from human tumor viruses in patient blood is a non‐invasive screening method for individuals at risk for developing cancer. A drawback is over‐diagnosis as these sensitive methods also detect non‐cancer‐related infections. Here the authors show by RNA sequencing and PCR amplification that a microRNA (BART13‐3p) encoded by the Epstein–Barr Virus (EBV) is associated with circulating vesicles in patients with nasopharyngeal carcinoma, thus distinguishing between cancer and non‐cancer‐related EBV infections.

Plasma EBV microRNAs in paediatric renal transplant recipients

BACKGROUND

Epstein-Barr virus (EBV) was the first human virus identified to express microRNA (miRNA). To date, 44 mature miRNAs are encoded for within the EBV genome. EBV miRNAs have not been profiled in paediatric renal transplant recipients. In this study, we investigated circulating EBV miRNA profiles as novel biomarkers in paediatric renal transplant patients.

METHODS

Forty-two microRNAs encoded within 2 EBV open reading frames (BART and BHRF) were examined in renal transplant recipients who resolved EBV infection (REI) or maintained chronic high viral loads (CHL), and in non-transplant patients with acute infectious mononucleosis (IM).

RESULTS

Plasma EBV-miR-BART2-5p was present in higher numbers of IM (7/8) and CHL (7/10) compared to REI (7/12) patients. A trend was observed between the numbers of plasma EBV miRNAs expressed and EBV viral load (p < 0.07). Several EBV-miRs including BART7-3p, 15, 9-3p, 11-3p, 1-3p and 3-3p were detected in IM and CHL patients only. The lytic EBV-miRs, BHRF1-2-3p and 1-1, indicating active viral replication, were detected in IM patients only. One CHL patient developed post-transplant lymphoproliferative disease (PTLD) after several years and analysis of 10 samples over a 30-month period showed an average 24-fold higher change in plasma EBV-miR-BART2-5p compared to the CHL group and 110-fold higher change compared to the REI group.

CONCLUSIONS

Our results suggest that EBV-miR-BART2-5p, which targets the stress-induced immune ligand MICB to escape recognition and elimination by NK cells, may have a role in sustaining high EBV viral loads in CHL paediatric kidney transplant recipients.