Tetraspanin CD63 Bridges Autophagic and Endosomal Processes To Regulate Exosomal Secretion and Intracellular Signaling of Epstein-Barr Virus LMP1

ABSTRACT The tetraspanin protein CD63 has been recently described as a key factor in extracellular vesicle (EV) production and endosomal cargo sorting. In the context of Epstein-Barr virus (EBV) infection, CD63 is required for the efficient packaging of the major viral oncoprotein latent membrane protein 1 (LMP1) into exosomes and other EV populations and acts as a negative regulator of LMP1 intracellular signaling. Accumulating evidence has also pointed to intersections of the endosomal and autophagy pathways in maintaining cellular secretory processes and as sites for viral assembly and replication. Indeed, LMP1 can activate the mammalian target of rapamycin (mTOR) pathway to suppress host cell autophagy and facilitate cell growth and proliferation. Despite the growing recognition of cross talk between endosomes and autophagosomes and its relevance to viral infection, little is understood about the molecular mechanisms governing endosomal and autophagy convergence. Here, we demonstrate that CD63-dependent vesicle protein secretion directly opposes intracellular signaling activation downstream of LMP1, including mTOR-associated proteins. Conversely, disruption of normal autolysosomal processes increases LMP1 secretion and dampens signal transduction by the viral protein. Increases in mTOR activation following CD63 knockout are coincident with the development of serum-dependent autophagic vacuoles that are acidified in the presence of high LMP1 levels. Altogether, these findings suggest a key role of CD63 in regulating the interactions between endosomal and autophagy processes and limiting cellular signaling activity in both noninfected and virally infected cells. IMPORTANCE The close connection between extracellular vesicles and viruses is becoming rapidly and more widely appreciated. EBV, a human gamma herpesvirus that contributes to the progression of a multitude of lymphomas and carcinomas in immunocompromised or genetically susceptible populations, packages its major oncoprotein, LMP1, into vesicles for secretion. We have recently described a role of the host cell protein CD63 in regulating intracellular signaling of the viral oncoprotein by shuttling LMP1 into exosomes. Here, we provide strong evidence of the utility of CD63-dependent EVs in regulating global intracellular signaling, including mTOR activation by LMP1. We also demonstrate a key role of CD63 in coordinating endosomal and autophagic processes to regulate LMP1 levels within the cell. Overall, this study offers new insights into the complex intersection of cellular secretory and degradative mechanisms and the implications of these processes in viral replication.

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Radio-Susceptibility of Nasopharyngeal Carcinoma: Focus on Epstein- Barr Virus, MicroRNAs, Long Non-Coding RNAs and Circular RNAs

Current Molecular Pharmacology ◽

10.2174/1874467213666191227104646 ◽

2020 ◽

Vol 13 (3) ◽

pp. 192-205 ◽

Cited By ~ 2

Author(s):

Fanghong Lei ◽

Tongda Lei ◽

Yun Huang ◽

Mingxiu Yang ◽

Mingchu Liao ◽

...

Keyword(s):

Nasopharyngeal Carcinoma ◽

Regulatory Networks ◽

Epstein Barr Virus ◽

Molecular Mechanisms ◽

Acquired Resistance ◽

Treatment Strategies ◽

Circular Rnas ◽

Barr Virus ◽

Non Coding Rnas ◽

Epstein Barr

Nasopharyngeal carcinoma (NPC) is a type of head and neck cancer. As a neoplastic disorder, NPC is a highly malignant squamous cell carcinoma that is derived from the nasopharyngeal epithelium. NPC is radiosensitive; radiotherapy or radiotherapy combining with chemotherapy are the main treatment strategies. However, both modalities are usually accompanied by complications and acquired resistance to radiotherapy is a significant impediment to effective NPC therapy. Therefore, there is an urgent need to discover effective radio-sensitization and radio-resistance biomarkers for NPC. Recent studies have shown that Epstein-Barr virus (EBV)-encoded products, microRNAs (miRNAs), long non-coding RNAs (lncRNAs) and circular RNAs (circRNAs), which share several common signaling pathways, can function in radio-related NPC cells or tissues. Understanding these interconnected regulatory networks will reveal the details of NPC radiation sensitivity and resistance. In this review, we discuss and summarize the specific molecular mechanisms of NPC radio-sensitization and radio-resistance, focusing on EBV-encoded products, miRNAs, lncRNAs and circRNAs. This will provide a foundation for the discovery of more accurate, effective and specific markers related to NPC radiotherapy. EBVencoded products, miRNAs, lncRNAs and circRNAs have emerged as crucial molecules mediating the radio-susceptibility of NPC. This understanding will improve the clinical application of markers and inform the development of novel therapeutics for NPC.

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Role of surgery in treating epstein‐barr virus‐associated smooth muscle tumor (EBV‐SMT) with central nervous system invasion: A systemic review from 1997 to 2019

Cancer Medicine ◽

10.1002/cam4.3770 ◽

2021 ◽

Vol 10 (5) ◽

pp. 1473-1484

Author(s):

Ka‐Wei Lau ◽

Yu‐Wei Hsu ◽

Yin‐Ting Lin ◽

Ko‐Ting Chen

Keyword(s):

Central Nervous System ◽

Nervous System ◽

Epstein Barr Virus ◽

Smooth Muscle Tumor ◽

Systemic Review ◽

Barr Virus ◽

Epstein Barr ◽

Central Nervous System Invasion ◽

Muscle Tumor

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Molecular Genetics in Epstein–Barr Virus-Associated Malignancies

Life ◽

10.3390/life11070593 ◽

2021 ◽

Vol 11 (7) ◽

pp. 593

Author(s):

Srikanth Umakanthan ◽

Maryann M Bukelo

Keyword(s):

Epstein Barr Virus ◽

Diagnostic Tools ◽

Main Role ◽

Genetic Changes ◽

Barr Virus ◽

Cancer Pathogenesis ◽

Genomic Studies ◽

Epstein Barr ◽

Oncogenic Form

Global genomic studies have detected the role of genomic alterations in the pathogenesis of Epstein–Barr virus (EBV)-associated tumors. EBV oncoproteins cause a vital shift of EBV from an infectious virus to an oncogenic form during the latent and lytic phase within the lymphoid B cells and epithelial cells. This epigenetic alteration modulates the virus and host genomes and inactivates and disrupts numerous tumor suppressors and signaling pathways. Genomic profiling has played the main role in identifying EBV cancer pathogenesis and its related targeted therapies. This article reviews the role of genetic changes in EBV-associated lymphomas and carcinomas. This includes the prolific molecular genesis, key diagnostic tools, and target-specific drugs that have been in recent clinical use.

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EBV load is associated with cfDNA fragmentation and renal damage in SLE patients

Lupus ◽

10.1177/09612033211010339 ◽

2021 ◽

pp. 096120332110103

Author(s):

Anna Truszewska ◽

Agnieszka Wirkowska ◽

Kamila Gala ◽

Piotr Truszewski ◽

Łucja Krzemień-Ojak ◽

...

Keyword(s):

Kidney Disease ◽

Lupus Erythematosus ◽

Epstein Barr Virus ◽

Renal Damage ◽

Healthy Individuals ◽

Pcr Assay ◽

Barr Virus ◽

Fragmentation Index ◽

Epstein Barr

Background For long Epstein–Barr virus (EBV) has been suspected to be involved in the pathogenesis of systemic lupus erythematosus (SLE). The aim of this study was to verify the association between EBV, cell-free DNA (cfDNA) and kidney disease in SLE. Methods Blood samples were obtained from 43 SLE patients and 50 healthy individuals. EBV load was measured via real-time PCR assay. Sizing and quantification of plasma cfDNA was performed on Bioanalyzer. We proposed that the uniformity of cfDNA fragmentation can be described using cfDNA fragmentation index. Results SLE patients with chronic kidney disease (CKD +) had higher EBV load compared to CKD(–) patients (P = 0.042). Patients with high cfDNA level had higher EBV load (P = 0.041) and higher cfDNA fragmentation index (P < 0.001) compared to patients with low cfDNA level. Among patients with high cfDNA level, EBV load was higher in CKD(+) group compared to CKD(–) group (P = 0.035). EBV load was positively correlated with the fragmentation index in all SLE patients (P = 0.028, R2 = 0.13), and the correlation was even more pronounced in CKD (+) patients (P < 0.001, R2 = 0.20). Conclusions We showed that EBV load was associated with non-uniform cfDNA fragmentation, higher cfDNA levels, and kidney disease in SLE patients. Although the causality of this relationship could not be determined with the current study, it brings rationale for further investigations on the role of EBV and cfDNA interplay in SLE pathogenesis.

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Promoter-Proximal Regulatory Elements Involved in oriP-EBNA1-Independent and -Dependent Activation of the Epstein-Barr Virus C Promoter in B-Lymphoid Cell Lines

Journal of Virology ◽

10.1128/jvi.75.13.5796-5811.2001 ◽

2001 ◽

Vol 75 (13) ◽

pp. 5796-5811 ◽

Cited By ~ 31

Author(s):

Tina Nilsson ◽

Henrik Zetterberg ◽

Yuyan Camilla Wang ◽

Lars Rymo

Keyword(s):

Transcription Factor ◽

Epstein Barr Virus ◽

Regulatory Elements ◽

Negative Regulator ◽

Regulatory Sequences ◽

Barr Virus ◽

Group I ◽

Epstein Barr ◽

B Lymphoid ◽

Virus C

ABSTRACT The identification of the cellular factors that control the transcription regulatory activity of the Epstein-Barr virus C promoter (Cp) is fundamental to the understanding of the molecular mechanisms that control virus latent gene expression. Using transient transfection of reporter plasmids in group I phenotype B-lymphoid cells, we have previously shown that the −248 to −55 region (−248/−55 region) of Cp contains elements that are essential fororiPI-EBNA1-dependent as well asoriPI-EBNA1-independent activation of the promoter. We now establish the importance of this region by a detailed mutational analysis of reporter plasmids carrying Cp regulatory sequences together with or without oriPI. The reporter plasmids were transfected into group I phenotype Rael cells and group III phenotype cbc-Rael cells, and the Cp activity measured was correlated with the binding of candidate transcription factors in electrophoretic mobility shift assays and further assessed in cotransfection experiments. We show that the NF-Y transcription factor interacts with the previously identified CCAAT box in the −71/−63 Cp region (M. T. Puglielli, M. Woisetschlaeger, and S. H. Speck, J. Virol. 70:5758–5768, 1996). We also show that members of the C/EBP transcription factor family interact with a C/EBP consensus sequence in the −119/−112 region of Cp and that this interaction is important for promoter activity. A central finding is the identification of a GC-rich sequence in the −99/−91 Cp region that is essential fororiPI-EBNA1-independent as well asoriPI-EBNA1-dependent activity of the promoter. This region contains overlapping binding sites for Sp1 and Egr-1, and our results suggest that Sp1 is a positive and Egr-1 is a negative regulator of Cp activity. Furthermore, we demonstrate that a reporter plasmid that in addition to oriPI contains only the −111/+76 region of Cp still retains the ability to be activated by EBNA1.

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