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1.
Front Immunol ; 13: 1011646, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36405723

RESUMO

Purpose: Heterozygous mutations in CTLA4 lead to an inborn error of immunity characterized by immune dysregulation and immunodeficiency, known as CTLA-4 insufficiency. Cohort studies on CTLA4 mutation carriers showed a reduced penetrance (around 70%) and variable disease expressivity, suggesting the presence of modifying factors. It is well studied that infections can trigger autoimmunity in humans, especially in combination with a genetic predisposition. Methods: To investigate whether specific infections or the presence of specific persisting pathogens are associated with disease onset or severity in CTLA-4 insufficiency, we have examined the humoral immune response in 13 CTLA4 mutation carriers, seven without clinical manifestation and six with autoimmune manifestations, but without immunoglobulin replacement therapy against cytomegalovirus (CMV), Epstein-Barr virus (EBV), herpes simplex virus 1/2 (HSV 1/2), parvovirus B19 and Toxoplasma gondii. Additionally, we have measured FcγRIII/CD16A activation by EBV-specific IgG antibodies to examine the functional capabilities of immunoglobulins produced by CTLA4 mutation carriers. Results: The seroprevalence between affected and unaffected CTLA4 mutation carriers did not differ significantly for the examined pathogens. Additionally, we show here that CTLA4 mutation carriers produce EBV-specific IgG, which are unimpaired in activating FcγRIII/CD16A. Conclusions: Our results show that the investigated pathogens are very unlikely to trigger the disease onset in CTLA-4-insufficient individuals, and their prevalence is not correlated with disease severity or expressivity.


Assuntos
Infecções por Vírus Epstein-Barr , Herpesvirus Humano 4 , Humanos , Antígeno CTLA-4/genética , Herpesvirus Humano 4/fisiologia , Infecções por Vírus Epstein-Barr/complicações , Infecções por Vírus Epstein-Barr/epidemiologia , Estudos Soroepidemiológicos , Anticorpos Antivirais , Imunoglobulina G
2.
PLoS Pathog ; 18(11): e1010990, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-36417478

RESUMO

Kaposi's sarcoma-associated herpesvirus (KSHV) and Epstein-Barr (EBV) are gammaherpesviruses associated with multiple human malignancies. KSHV is the etiological agent of Kaposi's Sarcoma, primary effusion lymphoma (PEL) and multicentric Castleman's disease (MCD). EBV is associated with Burkitt's lymphoma (BL), Hodgkin's lymphoma (HL), nasopharyngeal carcinoma (NPC) and gastric carcinoma (GC). KSHV and EBV establish life-long latency in the human host with intermittent periods of lytic reactivation. Here, we identified a cellular factor named transforming growth factor-beta regulator 4 (TBRG4) that plays a role in the gammaherpesvirus lifecycle. We find that TBRG4, a protein that is localized to the mitochondria, can regulate lytic reactivation from latency of both KSHV and EBV. Knockdown of TBRG4 in cells latently infected with KSHV or EBV induced viral lytic gene transcription and replication. TBRG4 deficiency causes mitochondrial stress and increases reactive oxygen species (ROS) production. Treatment with a ROS scavenger decreased viral reactivation from latency in TBRG4-depleted cells. These data suggest that TBRG4 serves as a cellular repressor of KSHV and EBV reactivation through the regulation of ROS production.


Assuntos
Herpesvirus Humano 4 , Herpesvirus Humano 8 , Proteínas Mitocondriais , Latência Viral , Humanos , Herpesvirus Humano 4/fisiologia , Herpesvirus Humano 8/fisiologia , Proteínas Mitocondriais/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Proteínas de Ligação a RNA/metabolismo
3.
Viruses ; 14(10)2022 09 22.
Artigo em Inglês | MEDLINE | ID: mdl-36298660

RESUMO

Among numerous causative agents recognized as oncogenic drivers, 13% of total cancer cases occur as a result of viral infections. The intricacy and diversity of carcinogenic processes, however, raise significant concerns about the mechanistic function of viruses in cancer. All tumor-associated viruses have been shown to encode viral oncogenes with a potential for cell transformation and the development of malignancies, including diffuse large B-cell lymphoma (DLBCL). Given the difficulties in identifying single mechanistic explanations, it is necessary to combine ideas from systems biology and viral evolution to comprehend the processes driving viral cancer. The potential for more efficient and acceptable therapies lies in targeted medicines that aim at viral proteins or trigger immune responses to either avoid infection or eliminate infected or cancerous cells. In this review, we aim to describe the role of viral infections and their mechanistic approaches in DLBCL tumorigenesis. To the best of our knowledge, this is the first review summarizing the oncogenic potential of numerous viral agents in DLBCL development.


Assuntos
Infecções por Vírus Epstein-Barr , Linfoma Difuso de Grandes Células B , Humanos , Herpesvirus Humano 4/fisiologia , Linfoma Difuso de Grandes Células B/complicações , Linfoma Difuso de Grandes Células B/patologia , Vírus Oncogênicos , Carcinogênese , Proteínas Virais
4.
Viruses ; 14(9)2022 08 25.
Artigo em Inglês | MEDLINE | ID: mdl-36146679

RESUMO

Beyond their pulmonary disease, many COVID-19 patients experience a complex constellation of characteristics, including hyperinflammatory responses, autoimmune disorders, and coagulopathies. However, the pathogenesis of these aspects of COVID-19 is obscure. More than 90% of people are latently infected with the lymphotropic herpesviruses Epstein-Barr Virus (EBV) and/or Human Herpesvirus-6 (HHV-6). Some of the inflammatory features of COVID-19 resemble clinical syndromes seen during EBV and HHV-6 infection, and these latent viruses can be reactivated by inflammatory mediators. We hypothesized that EBV and HHV-6 reactivation might be a common feature of early COVID-19, particularly in patients with more inflammation. We tested for EBV and HHV-6 reactivation in 67 patients acutely hospitalized with COVID-19 using previously validated quantitative PCR assays on the plasma. In our cohort, we found that 15/67 (22.4%) patients had detectable EBV and 3/67 (4.5%) had detectable HHV-6. This frequency of activation is somewhat more than the frequency reported for some healthy cohorts, such as blood donors and other healthy control cohorts. There was no association between EBV or HHV-6 and markers indicative of more inflammatory disease. We conclude that EBV and HHV-6 activation at about day 7 of hospitalization occurred in a modest fraction of our cohort of COVID-19 patients and was not associated with high levels of inflammation. In the modest fraction of patients, EBV and HHV-6 reactivation could contribute to some features of acute disease and pre-disposition to post-acute sequelae in a subset of patients.


Assuntos
COVID-19 , Infecções por Vírus Epstein-Barr , Herpesvirus Humano 6 , Herpesvirus Humano 8 , Infecções por Vírus Epstein-Barr/complicações , Herpesvirus Humano 4/fisiologia , Herpesvirus Humano 6/fisiologia , Humanos , Inflamação , Mediadores da Inflamação
5.
Front Immunol ; 13: 967026, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36119024

RESUMO

Rituximab is used to eliminate B cells as a chimeric monoclonal antibody directed against CD20, a B-cell antigen expressed on B cells. To explore the impact of rituximab administered before transplantation, we implemented a retrospective, monocentric study and utilized real-world data collected at our center between January 2018 and December 2020, and then followed until December 2021. Based on whether a dose of 375mg/m2 rituximab was used at least once within two weeks before transplantation, patients undergoing allo-HSCT were classified into two groups: rituximab (N=176) and non-rituximab (N=344) group. Amongst all the patients, the application of rituximab decreased EBV reactivation (P<0.01) and rituximab was an independent factor in the prevention of EBV reactivation by both univariate and multivariate analyses (HR 0.56, 95%CI 0.33-0.97, P=0.04). In AML patients, there were significant differences in the cumulative incidence of aGVHD between the two groups (P=0.04). Our data showed that rituximab was association with a decreased incidence of aGVHD in AML patients according to both univariate and multivariate analyses. There was no difference between the two groups in other sets of populations. Thus, our study indicated that rituximab administered before transplantation may help prevent EBV reactivation in all allo-HSCT patients, as well as prevent aGVHD in AML patients after allo-HSCT.


Assuntos
Transplante de Células-Tronco Hematopoéticas , Leucemia Mieloide Aguda , Transplante de Células-Tronco Hematopoéticas/efeitos adversos , Herpesvirus Humano 4/fisiologia , Humanos , Leucemia Mieloide Aguda/tratamento farmacológico , Estudos Retrospectivos , Rituximab/uso terapêutico , Ativação Viral
6.
Cell Rep ; 40(9): 111286, 2022 08 30.
Artigo em Inglês | MEDLINE | ID: mdl-36044865

RESUMO

Epstein-Barr virus infection of B lymphocytes elicits diverse host responses via well-adapted transcriptional control dynamics. Consequently, this host-pathogen interaction provides a powerful system to explore fundamental processes leading to consensus fate decisions. Here, we use single-cell transcriptomics to construct a genome-wide multistate model of B cell fates upon EBV infection. Additional single-cell data from human tonsils reveal correspondence of model states to analogous in vivo phenotypes within secondary lymphoid tissue, including an EBV+ analog of multipotent activated precursors that can yield early memory B cells. These resources yield exquisitely detailed perspectives of the transforming cellular landscape during an oncogenic viral infection that simulates antigen-induced B cell activation and differentiation. Thus, they support investigations of state-specific EBV-host dynamics, effector B cell fates, and lymphomagenesis. To demonstrate this potential, we identify EBV infection dynamics in FCRL4+/TBX21+ atypical memory B cells that are pathogenically associated with numerous immune disorders.


Assuntos
Infecções por Vírus Epstein-Barr , Linfócitos B , Infecções por Vírus Epstein-Barr/genética , Herpesvirus Humano 4/fisiologia , Interações Hospedeiro-Patógeno , Humanos , Transcriptoma/genética
7.
Chem Biodivers ; 19(9): e202200527, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-35979671

RESUMO

Although primary infection of Epstein-Barr virus is generally non-lethal, viral reactivation is often associated with fatal outcomes. Regardless, there is no FDA-approved treatment available for this omnipresent viral infection. The current investigation targets viral maintenance and reactivation by inhibiting the functioning of viral deoxyuridine-triphosphatase (dUTPase) using phytochemicals. The EBV-dUTPase is essential for maintaining nucleotide balance and thus, plays a vital role in the viral replication cycle. Additionally, the protein has shown neuroinflammatory effects on the host. To selectively target the protein and possibly alter its activity, we utilized a virtual screening approach and screened 45 phytochemicals reported to have antiviral, anti-inflammatory, and neuroprotective properties. The analysis revealed several phytochemicals bound to the target protein with high affinity. In-silico ADMET and Lipinski's rule analysis predicted favorable druggability of Dehydroevodiamine (DHE) among all the phytochemicals. Further, we corroborated our findings by molecular dynamic simulation and binding affinity estimation. Our outcomes ascertained a stable binding of DHE to EBV-dUTPase primarily through electrostatic interactions. We identified that the protein-ligand binding involves the region around His71, previously reported as a potent drug target site. Conclusively, the phytochemical DHE showed a promising future as a drug development candidate against EBV-dUTPase.


Assuntos
Infecções por Vírus Epstein-Barr , Herpesvirus Humano 4 , Anti-Inflamatórios/farmacologia , Antivirais/farmacologia , Desoxiuridina , Infecções por Vírus Epstein-Barr/tratamento farmacológico , Herpesvirus Humano 4/fisiologia , Humanos , Ligantes , Nucleotídeos , Compostos Fitoquímicos/farmacologia , Pirofosfatases
8.
J Virol ; 96(17): e0102822, 2022 09 14.
Artigo em Inglês | MEDLINE | ID: mdl-35969079

RESUMO

Herpesviruses establish latency to ensure permanent residence in their hosts. Upon entry into a cell, these viruses are rapidly silenced by the host, thereby limiting the destructive viral lytic phase while allowing the virus to hide from the immune system. Notably, although the establishment of latency by the oncogenic herpesvirus Epstein-Barr virus (EBV) requires the expression of viral latency genes, latency can be maintained with a negligible expression of viral genes. Indeed, in several herpesviruses, the host DNA sensor IFI16 facilitated latency via H3K9me3 heterochromatinization. This silencing mark is typically imposed by the constitutive heterochromatin machinery (HCM). The HCM, in an antiviral role, also silences the lytic phase of EBV and other herpes viruses. We investigated if IFI16 restricted EBV lytic activation by partnering with the HCM and found that IFI16 interacted with core components of the HCM, including the KRAB-associated protein 1 (KAP1) and the site-specific DNA binding KRAB-ZFP SZF1. This partnership silenced the EBV lytic switch protein ZEBRA, encoded by the BZLF1 gene, thereby favoring viral latency. Indeed, IFI16 contributed to H3K9 trimethylation at lytic genes of all kinetic classes. In defining topology, we found that IFI16 coenriched with KAP1 at the BZLF1 promoter, and while IFI16 and SZF1 were each adjacent to KAP1 in latent cells, IFI16 and SZF1 were not. Importantly, we also found that disruption of latency involved rapid downregulation of IFI16 transcription. These findings revealed a previously unknown partnership between IFI16 and the core HCM that supports EBV latency via antiviral heterochromatic silencing. IMPORTANCE The interferon-gamma inducible protein 16 (IFI16) is a nuclear DNA sensor that mediates antiviral responses by activating the inflammasome, triggering an interferon response, and silencing lytic genes of herpesviruses. The last, which helps maintain latency of the oncoherpesvirus Epstein-Barr virus (EBV), is accomplished via H3K9me3 heterochromatinization through unknown mechanisms. Here, we report that IFI16 physically partners with the core constitutive heterochromatin machinery to silence the key EBV lytic switch protein, thereby ensuring continued viral latency in B lymphocytes. We also find that disruption of latency involves rapid transcriptional downregulation of IFI16. These findings point to hitherto unknown physical and functional partnerships between a well-known antiviral mechanism and the core components of the constitutive heterochromatin machinery.


Assuntos
Infecções por Vírus Epstein-Barr , Herpesvirus Humano 4 , Proteínas Nucleares , Fosfoproteínas , Proteína 28 com Motivo Tripartido , Latência Viral , Linhagem Celular Tumoral , Infecções por Vírus Epstein-Barr/genética , Regulação Viral da Expressão Gênica , Herpesvirus Humano 4/fisiologia , Heterocromatina/genética , Heterocromatina/metabolismo , Humanos , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , Fosfoproteínas/genética , Fosfoproteínas/metabolismo , Fatores de Transcrição/metabolismo , Proteína 28 com Motivo Tripartido/genética , Proteína 28 com Motivo Tripartido/metabolismo , Ativação Viral
9.
Int J Mol Sci ; 23(16)2022 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-36012375

RESUMO

It is emerging that targeting the adaptive functions of Unfolded Protein Response (UPR) may represent a promising anti-cancer therapeutic approach. This is particularly relevant for B-cell lymphomas, characterized by a high level of constitutive stress due to high c-Myc expression. In this study, we found that IRE1α/XBP1 axis inhibition exerted a stronger cytotoxic effect compared to the inhibition of the other two UPR sensors, namely PERK and ATF6, in Burkitt lymphoma (BL) cells, in correlation with c-Myc downregulation. Interestingly, such an effect was more evident in Epstein-Barr virus (EBV)-negative BL cells or those cells expressing type I latency compared to type III latency BL cells. The other interesting finding of this study was that the inhibition of IRE1α/XBP1 downregulated BRCA-1 and RAD51 and potentiated the cytotoxicity of PARP inhibitor AZD2661 against BL cells and also against Primary Effusion Lymphoma (PEL), another aggressive B-cell lymphoma driven by c-Myc and associated with gammaherpesvirus infection. These results suggest that combining the inhibition of UPR sensors, particularly IRE1α/XBP1 axis, and molecules involved in DDR, such as PARP, could offer a new therapeutic opportunity for treating aggressive B-cell lymphomas such as BL and PEL.


Assuntos
Linfoma de Burkitt , Infecções por Vírus Epstein-Barr , Inibidores de Poli(ADP-Ribose) Polimerases , Resposta a Proteínas não Dobradas , Linfoma de Burkitt/tratamento farmacológico , Linfoma de Burkitt/virologia , Endorribonucleases/genética , Endorribonucleases/metabolismo , Infecções por Vírus Epstein-Barr/tratamento farmacológico , Herpesvirus Humano 4/fisiologia , Humanos , Inibidores de Poli(ADP-Ribose) Polimerases/farmacologia , Proteínas Serina-Treonina Quinases/genética , Proteína 1 de Ligação a X-Box/genética , Proteína 1 de Ligação a X-Box/metabolismo
10.
Integr Biol (Camb) ; 14(4): 89-97, 2022 07 11.
Artigo em Inglês | MEDLINE | ID: mdl-35780312

RESUMO

The brain microvascular endothelial cells (ECs) play an important role in protecting the brain from hazardous pathogens. However, some viral pathogens can smartly modulate the endothelial pathways to gain entry inside the brain. Further, these viruses can cause endothelial dysfunction which could develop serious neurological ailments. Epstein-Barr virus (EBV), an oncogenic virus, has also been linked to various neurological disorders. The virus primarily infects epithelial and B cells, however, it also has a tendency to infect ECs and cause endothelial activation. However, the impact of EBV influence on ECs is still underexplored. Studying the early events of virus-mediated cellular modulation could help in understanding the virus' infection strategy or aftermath. Raman microspectroscopy has been widely utilized in biomedical sciences to decipher cellular changes. To understand the EBV-influenced EC modulation by studying intracellular biomolecular changes at early time points, we utilized the Raman microspectroscopy tool. We treated the ECs with EBV and acquired the Raman spectra at different time points (2, 4, 6, 12, 24 and 36 h) and different sites (nucleus and periphery) to check changes in Raman intensities associated with specific biomolecules. In the EBV-treated cells, the status of various biomolecules in terms of Raman intensities was observed to be altered compared with uninfected cells. Specifically, the cholesterol, polysaccharide, nucleotides, nucleic acid and proline moieties were altered at different time points. We also investigated the possible correlation between these molecules using molecular network analysis and observed various associated factors. These factors could be influenced by EBV to alter the associated biomolecular levels. Our study paves the pathway to study EBV infection in human brain microvascular ECs and highlights specific biomolecular alterations, which can be focused for further mechanistic investigations.


Assuntos
Infecções por Vírus Epstein-Barr , Herpesvirus Humano 4 , Linfócitos B , Encéfalo/metabolismo , Células Endoteliais/metabolismo , Infecções por Vírus Epstein-Barr/metabolismo , Herpesvirus Humano 4/fisiologia , Humanos
11.
Front Immunol ; 13: 858583, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35874728

RESUMO

Epstein-Barr virus (EBV) has been identified as a putative trigger of multiple sclerosis (MS). Previously, we reported that mice latently infected with murine gammaherpesvirus 68 (γHV-68), the murine homolog to EBV, and induced for experimental autoimmune encephalomyelitis (EAE), developed an enhanced disease more reminiscent of MS. These prior results showed that expression of CD40 on CD11b+CD11c+ cells in latently infected mice was required to prime the strong Th1 response driving disease as well as decreasing Treg frequencies in the periphery and CNS. Subsequent work demonstrated that transfer of B cells from latently infected mice was sufficient to enhance disease. Herein, we show that B cells from infected mice do not need type I IFN signaling to drive a strong Th1 response, yet are important in driving infiltration of the CNS by CD8+ T cells. Given the importance of type I IFNs in MS, we used IFNARko mice in order to determine if type I IFN signaling was important in the enhancement of EAE in latently infected mice. We found that while type I IFNs are important for the control of γHV-68 infection and maintenance of latency, they do not have a direct effect in the development of enhanced EAE.


Assuntos
Encefalomielite Autoimune Experimental , Infecções por Vírus Epstein-Barr , Interferon Tipo I , Esclerose Múltipla , Animais , Linfócitos T CD8-Positivos , Herpesvirus Humano 4/fisiologia , Camundongos
12.
Front Immunol ; 13: 903063, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35903096

RESUMO

Epstein-Barr virus (EBV) establishes a lifelong latent infection in healthy humans, kept under immune control by cytotoxic T cells (CTLs). Following paediatric haematopoetic stem cell transplantation (HSCT), a loss of immune surveillance leads to opportunistic outgrowth of EBV-infected cells, resulting in EBV reactivation, which can ultimately progress to post-transplant lymphoproliferative disorder (PTLD). The aims of this study were to identify risk factors for EBV reactivation in children in the first 100 days post-HSCT and to assess the suitability of a previously reported mathematical model to mechanistically model EBV reactivation kinetics in this cohort. Retrospective electronic data were collected from 56 children who underwent HSCT at Great Ormond Street Hospital (GOSH) between 2005 and 2016. Using EBV viral load (VL) measurements from weekly quantitative PCR (qPCR) monitoring post-HSCT, a multivariable Cox proportional hazards (Cox-PH) model was developed to assess time to first EBV reactivation event in the first 100 days post-HSCT. Sensitivity analysis of a previously reported mathematical model was performed to identify key parameters affecting EBV VL. Cox-PH modelling revealed EBV seropositivity of the HSCT recipient and administration of anti-thymocyte globulin (ATG) pre-HSCT to be significantly associated with an increased risk of EBV reactivation in the first 100 days post-HSCT (adjusted hazard ratio (AHR) = 2.32, P = 0.02; AHR = 2.55, P = 0.04). Five parameters were found to affect EBV VL in sensitivity analysis of the previously reported mathematical model. In conclusion, we have assessed the effect of multiple covariates on EBV reactivation in the first 100 days post-HSCT in children and have identified key parameters in a previously reported mechanistic mathematical model that affect EBV VL. Future work will aim to fit this model to patient EBV VLs, develop the model to account for interindividual variability and model the effect of clinically relevant covariates such as rituximab therapy and ATG on EBV VL.


Assuntos
Infecções por Vírus Epstein-Barr , Transplante de Células-Tronco Hematopoéticas , Soro Antilinfocitário , Criança , Infecções por Vírus Epstein-Barr/complicações , Transplante de Células-Tronco Hematopoéticas/efeitos adversos , Herpesvirus Humano 4/fisiologia , Humanos , Modelos Teóricos , Estudos Retrospectivos , Fatores de Risco
13.
Molecules ; 27(14)2022 Jul 21.
Artigo em Inglês | MEDLINE | ID: mdl-35889536

RESUMO

Reactivation of Epstein-Barr virus (EBV) is associated with EBV-associated malignancies and is considered to be a benefit target for treatment. Andrographolide is claimed to have antiviral and anti-tumor activities. Therefore, this study aimed to investigate the effect of andrographolide on the inhibition of EBV lytic reactivation in EBV-positive cancer cells. The cytotoxicity of andrographolide was firstly evaluated in EBV-positive cancer cells; P3HR1, AGS-EBV and HONE1-EBV cells, using an MTT assay. Herein, the spontaneous expression of EBV lytic genes; BALF5, BRLF1 and BZLF1, was significantly inhibited in andrographolide-treated cells. Accordingly, andrographolide inhibited the expression of Zta and viral production in sodium butyrate (NaB)-induced EBV lytic reactivation. Additionally, proteomics and bioinformatics analysis revealed the differentially expressed proteins that inhibit EBV lytic reactivation in all treated cell lines were functionally related with the histone modifications and chromatin organization, such as histone H3-K9 modification and histone H3-K27 methylation. Taken together, andrographolide inhibits EBV reactivation in EBV-positive cancer cells by inhibiting EBV lytic genes, probably, through the histone modifications.


Assuntos
Infecções por Vírus Epstein-Barr , Neoplasias , Linhagem Celular , Diterpenos , Epigênese Genética , Herpesvirus Humano 4/fisiologia , Histonas/metabolismo , Humanos , Neoplasias/genética , Transativadores/genética , Ativação Viral
14.
J Virol ; 96(14): e0051822, 2022 Jul 27.
Artigo em Inglês | MEDLINE | ID: mdl-35862711

RESUMO

Protein-protein interactions (PPIs) are crucial for various biological processes. Epstein-Barr virus (EBV) proteins typically form complexes, regulating the replication and persistence of the viral genome in human cells. However, the role of EBV protein complexes under physiological conditions remains unclear. In this study, we performed comprehensive analyses of EBV PPIs in living cells using the NanoBiT system. We identified 195 PPIs, many of which have not previously been reported. Computational analyses of these PPIs revealed that BLRF2, which is only found in gammaherpesviruses, is a central protein in the structural network of EBV tegument proteins. To characterize the role of BLRF2, we generated two BLRF2 knockout EBV clones using CRISPR/Cas9. BLRF2 knockout significantly decreased the production of infectious virus particles, which was partially restored by exogenous BLRF2 expression. In addition, self-association of BLRF2 protein was found, and mutation of the residues crucial for the self-association affected stability of the protein. Our data imply that BLRF2 is a tegument network hub that plays important roles in progeny virion maturation. IMPORTANCE EBV remains a significant public health challenge, causing infectious mononucleosis and several cancer types. Therefore, the better understanding of the molecular mechanisms underlying EBV replication is of high clinical importance. As protein-protein interactions (PPIs) are major regulators of virus-associated pathogenesis, comprehensive analyses of PPIs are essential. Previous studies on PPIs in EBV or other herpesviruses have predominantly employed the yeast two-hybrid (Y2H) system, immunoprecipitation, and pulldown assays. Herein, using a novel luminescence-based method, we identified 195 PPIs, most of which have not previously been reported. Computational and functional analyses using knockout viruses revealed that BLRF2 plays a central role in the EBV life cycle, which makes it a valuable target for drug development.


Assuntos
Infecções por Vírus Epstein-Barr , Gammaherpesvirinae , Herpesvirus Humano 4/fisiologia , Humanos , Replicação Viral/genética
15.
mBio ; 13(3): e0083622, 2022 06 28.
Artigo em Inglês | MEDLINE | ID: mdl-35642944

RESUMO

The oncogenic gammaherpesviruses, including human Epstein-Barr virus (EBV), human Kaposi's sarcoma-associated herpesvirus (KSHV), and murine gammaherpesvirus 68 (MHV68, γHV68, MuHV-4), are associated with numerous malignancies, including B cell lymphomas and nasopharyngeal carcinoma. These viruses employ numerous molecular strategies to colonize the host, including the expression of noncoding RNAs (ncRNAs). As the first viral ncRNAs identified, EBV-encoded RNA 1 and 2 (EBER1 and EBER2, respectively) have been investigated extensively for decades; however, their specific in vivo functions remain largely unknown. In work here, we used chimeric MHV68 viruses in an in vivo complementation system to test whether EBV EBER2 contributes to acute and/or chronic phases of infection. Expression of EBER2 derived from EBV strain B95-8 resulted in a significant expansion of latently infected B cells in vivo, which was accompanied by a decrease in virus-infected plasma cells. EBV strains typically carry one of two variants of EBER2, which differ primarily by a 5-nucleotide core polymorphism identified initially in the EBV strain M81. Strikingly, mutation of the 5 nucleotides that define this core polymorphism resulted in the loss of the infected B cell expansion and restored plasma cell infection. This work reveals that the B95-8 variant of EBER2 promotes the expansion of the latently infected B cell pool in vivo and may do so in part through inhibition of terminal differentiation. These findings provide new insight into mechanisms by which viral ncRNAs promote in vivo colonization and further and provide further evidence of the inherent tumorigenic risks associated with gammaherpesvirus manipulation of B cell differentiation. IMPORTANCE The oncogenic gammaherpesviruses, including human Epstein-Barr virus (EBV), human Kaposi's sarcoma-associated herpesvirus (KSHV), and murine gammaherpesvirus 68, employ numerous strategies to colonize the host, including expression of noncoding RNAs (ncRNAs). As the first viral ncRNAs ever identified, EBV-encoded RNA 1 and 2 (EBER1 and EBER2) have been investigated extensively for decades; however, their specific in vivo functions remain largely unknown. Work here reveals that an EBV EBER2 variant highly associated with B cell lymphoma promoted a significantly increased expansion of the infected B cell pool in vivo, which coincided with altered B cell differentiation. Mutation of the 5 nucleotides that define this EBER2 variant resulted in the loss of B cell expansion and normal B cell differentiation. These findings provide new insight into the mechanisms by which EBV manipulates B cells in vivo to retain infected cells in the high-risk B cell differentiation pathway where they are poised for tumorigenesis.


Assuntos
Infecções por Vírus Epstein-Barr , Gammaherpesvirinae , Herpesvirus Humano 8 , Rhadinovirus , Animais , Infecções por Vírus Epstein-Barr/genética , Gammaherpesvirinae/genética , Herpesvirus Humano 4/fisiologia , Herpesvirus Humano 8/genética , Humanos , Camundongos , Nucleotídeos , Polimorfismo Genético , RNA não Traduzido/genética , RNA não Traduzido/metabolismo , RNA Viral , Rhadinovirus/genética , Latência Viral/genética
16.
Clin Lab ; 68(5)2022 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-35536068

RESUMO

BACKGROUND: The combination of EBV associated myositis and hemophagocytic syndrome is very rare and is lacking sufficient clinical study. The authors describe a novel case of myositis and hemophagocytic syndrome in a 17-year-old boy with chronic EBV infection. METHODS: Hematological and immunological blood investigation, bone marrow aspirate, labial and muscle pathological test and immunohistochemistry staining of Epstein-Barr virus-encoded small RNA (EBER) were performed. RESULTS: The patient was started on prednisolone and methotrexate for treatment of the myositis and his symptoms decrease for 2 months and rapidly progressed with worsening cytopenia, liver function tests, and coagulation profile. The patient was treated empirically with intravenous antibiotics and human immunoglobulin G. He developed fulminant hemophagocytic syndrome and passed away due to multiorgan failure 14 months after the onset of the disease. CONCLUSIONS: Performing a limited IHC with EBER will be helpful to diagnose EBV infection involving muscle. EBV infection as a prognostic factor of myositis needs further studies.


Assuntos
Infecções por Vírus Epstein-Barr , Linfo-Histiocitose Hemofagocítica , Miosite , Polimiosite , Adolescente , Infecções por Vírus Epstein-Barr/complicações , Infecções por Vírus Epstein-Barr/diagnóstico , Herpesvirus Humano 4/fisiologia , Humanos , Linfo-Histiocitose Hemofagocítica/diagnóstico , Masculino , Miosite/diagnóstico , Polimiosite/diagnóstico
17.
J Transl Med ; 20(1): 217, 2022 05 13.
Artigo em Inglês | MEDLINE | ID: mdl-35562811

RESUMO

BACKGROUND: The two oncogenic human gammaherpesviruses, Kaposi sarcoma-associated herpesvirus (KSHV) and Epstein-Barr virus (EBV), both downregulate immune surface molecules, such as MHC-I, ICAM-1, and B7-2, enabling them to evade T-cell and natural killer cell immunity. Both also either encode for human cyclin homologues or promote cellular cyclin activity, and this has been shown to be important for proliferation and survival of gammaherpesvirus-induced tumors. CDK4/6 inhibitors, which are approved for certain breast cancers, have been shown to enhance expression of MHC-I in cell lines and murine models of breast cancer, and this was attributed to activation of interferons by endogenous retrovirus elements. However, it was not known if this would occur in gammaherpesvirus-induced tumors in which interferons are already activated. METHODS: Multiple KSHV/EBV-infected cell lines were treated with CDK4/6 inhibitors. The growth of viable cells and expression of surface markers was assessed. T cell activation stimulated by the treated cells was assayed by a T-cell activation bioassay. Both viral and host gene expression was surveyed using RT-qPCR. RESULTS: Three CDK4/6 inhibitors, abemaciclib, palbociclib, and ribociclib, inhibited cell growth in KSHV-induced primary effusion lymphoma (PEL) and EBV positive Burkitt's lymphoma (BL) cell lines, and KSHV-infected human umbilical vein endothelial cells (HUVECs). Moreover, CDK4/6 inhibitors increased mRNA and surface expression of MHC-I in all three and prevented downregulation of MHC-I surface expression during lytic replication in KSHV-infected cells. CDK4/6 inhibitors also variably increased mRNA and surface expression of ICAM-1 and B7-2 in the tested lines. Abemaciclib also significantly enhanced T-cell activation induced by treated PEL and BL cells. Certain gammaherpesvirus genes as well as endogenous retrovirus (ERV) 3-1 genes were enhanced by CDK4/6 inhibitors in most PEL and BL lines and this enhancement was associated with expression of gamma interferon-induced genes including MHC-I. CONCLUSIONS: These observations provide evidence that CDK4/6 inhibitors can induce expression of surface immune markers MHC-I, B7-2, and ICAM-1 in gammaherpesvirus-infected cell lines and induce virus-specific immunity. They can thus thwart virus-induced immune evasion. These effects, along with their direct effects on KSHV- or EBV-induced tumors, provide a rational for the clinical testing of these drugs in these tumors.


Assuntos
Infecções por Vírus Epstein-Barr , Herpesvirus Humano 8 , Neoplasias , Animais , Morte Celular , Quinase 4 Dependente de Ciclina , Quinase 6 Dependente de Ciclina , Ciclinas , Células Endoteliais , Infecções por Vírus Epstein-Barr/complicações , Herpesvirus Humano 4/fisiologia , Herpesvirus Humano 8/fisiologia , Humanos , Molécula 1 de Adesão Intercelular , Interferons , Neoplasias/complicações , RNA Mensageiro , Linfócitos T
18.
PLoS Pathog ; 18(4): e1010206, 2022 04.
Artigo em Inglês | MEDLINE | ID: mdl-35452490

RESUMO

Reconstitution of the T cell repertoire after allogeneic stem cell transplantation is a long and often incomplete process. As a result, reactivation of Epstein-Barr virus (EBV) is a frequent complication that may be treated by adoptive transfer of donor-derived EBV-specific T cells. We generated donor-derived EBV-specific T cells by stimulation with peptides representing defined epitopes covering multiple HLA restrictions. T cells were adoptively transferred to a patient who had developed persisting high titers of EBV after allogeneic stem cell transplantation for angioimmunoblastic T-cell lymphoma (AITL). T cell receptor beta (TCRß) deep sequencing showed that the T cell repertoire of the patient early after transplantation (day 60) was strongly reduced and only very low numbers of EBV-specific T cells were detectable. Manufacturing and in vitro expansion of donor-derived EBV-specific T cells resulted in enrichment of EBV epitope-specific, HLA-restricted T cells. Monitoring of T cell clonotypes at a molecular level after adoptive transfer revealed that the dominant TCR sequences from peptide-stimulated T cells persisted long-term and established an EBV-specific TCR clonotype repertoire in the host, with many of the EBV-specific TCRs present in the donor. This reconstituted repertoire was associated with immunological control of EBV and with lack of further AITL relapse.


Assuntos
Infecções por Vírus Epstein-Barr , Transplante de Células-Tronco Hematopoéticas , Transferência Adotiva , Epitopos , Herpesvirus Humano 4/fisiologia , Humanos , Peptídeo T , Peptídeos , Linfócitos T
19.
mBio ; 13(3): e0065522, 2022 06 28.
Artigo em Inglês | MEDLINE | ID: mdl-35435703

RESUMO

This study assessed the effects of Epstein-Barr virus (EBV) and one form of virally encoded BART long noncoding RNAs (lncRNAs) on cellular expression in epithelial cells grown in vitro and as tumors in vivo determined by high-throughput RNA sequencing of mRNA and small RNAs. Hierarchical clustering based on gene expression distinguished the cell lines from the tumors and distinguished the EBV-positive tumors and the BART tumors from the EBV-negative tumors. EBV and BART expression also induced specific expression changes in cellular microRNAs (miRs) and lncRNAs. Multiple known and predicted targets of the viral miRs, the induced cellular miRs, and lncRNAs were identified in the altered gene set. The changes in expression in vivo indicated that the suppression of growth pathways in vivo reflects increased expression of cellular miRs in all tumors. In the EBV and BART tumors, many of the targets of the induced miRs were not changed and the seed sequences of the nonfunctional miRs were found to have homologous regions within the BART lncRNA. The inhibition of these miR effects on known targets suggests that these induced miRs have reduced function due to sponging by the BART lncRNA. This composite analysis identified the effects of EBV on cellular miRs and lncRNAs with a functional readout through identification of the simultaneous effects on gene expression. Major shifts in gene expression in vivo are likely mediated by effects on cellular noncoding RNAs. Additionally, a predicted property of the BART lncRNA is to functionally inhibit the induced cellular miRs. IMPORTANCE This study identified the total effects of EBV and a viral long noncoding RNA (BART lncRNA) on cellular RNA expression when grown as cells in culture and when grown as tumors in immunodeficient mice. The effects on cellular mRNA expression, lncRNA expression, and cellular and viral miR expression were determined using next-generation sequencing (NGS) and bioinformatics functional analysis. Many cellular growth pathways that are activated during growth in culture are decreased during growth as tumors. This study shows that these changes in expression are accompanied by induction of cellular-growth-inhibitory miRs. However, in the EBV tumors and in tumors expressing the BART lncRNA, many of the known targets of the inhibitory miRs are not affected. Regions of strong homology to the seed sequences of these miRs were identified in the BART lncRNA. These findings suggest that the BART lncRNA functions as a sponge for growth-inhibitory miRs.


Assuntos
Infecções por Vírus Epstein-Barr , MicroRNAs , Neoplasias , RNA Longo não Codificante , Animais , Herpesvirus Humano 4/fisiologia , Camundongos , MicroRNAs/genética , MicroRNAs/metabolismo , RNA Longo não Codificante/genética , RNA Mensageiro , RNA Viral/genética
20.
J Virol ; 96(9): e0033622, 2022 05 11.
Artigo em Inglês | MEDLINE | ID: mdl-35404082

RESUMO

Epstein-Barr virus (EBV), the first identified human tumor virus, is etiologically associated with various kinds of malignant and benign diseases, accounting for 265,000 cancer incident cases and 164,000 cancer deaths in 2017. EBV prophylactic vaccine development has been gp350 centered for several decades. However, clinical studies show that gp350-centered vaccines fail to prevent EBV infection. Advances in the EBV infection mechanisms shed light on gB and gHgL, the two key components of the infection apparatus. In this study, for the first time, we utilized recombinant vesicular stomatitis virus (VSV) to display EBV gB (VSV-ΔG-gB/gB-G) or gHgL (VSV-ΔG-gHgL). In vitro studies confirmed successful virion production and glycoprotein presentation on the virion surface. In mouse models, VSV-ΔG-gB/gB-G or VSV-ΔG-gHgL elicited potent humoral responses. Neutralizing antibodies elicited by VSV-ΔG-gB/gB-G were prone to prevent B cell infection, while those elicited by VSV-ΔG-gHgL were prone to prevent epithelial cell infection. Combinatorial vaccination yields an additive effect. The ratio of endpoint neutralizing antibody titers to the endpoint total IgG titers immunized with VSV-ΔG-gHgL was approximately 1. The ratio of IgG1/IgG2a after VSV-ΔG-gB/gB-G immunization was approximately 1 in a dose-dependent, adjuvant-independent manner. Taken together, VSV-based EBV vaccines can elicit a high ratio of epithelial and B lymphocyte neutralizing antibodies, implying their unique potential as EBV prophylactic vaccine candidates. IMPORTANCE Epstein-Barr virus (EBV), one of the most common human viruses and the first identified human oncogenic virus, accounted for 265,000 cancer incident cases and 164,000 cancer deaths in 2017 as well as millions of nonmalignant disease cases. So far, no prophylactic vaccine is available to prevent EBV infection. In this study, for the first time, we reported the VSV-based EBV vaccines presenting two key components of the EBV infection apparatus, gB and gHgL. We confirmed potent antigen-specific antibody generation; these antibodies prevented EBV from infecting epithelial cells and B cells, and the IgG1/IgG2a ratio indicated balanced humoral-cellular responses. Taken together, we suggest VSV-based EBV vaccines are potent prophylactic candidates for clinical studies and help eradicate numerous EBV-associated malignant and benign diseases.


Assuntos
Infecções por Vírus Epstein-Barr , Vesiculovirus , Vacinas Virais , Animais , Anticorpos Neutralizantes/sangue , Anticorpos Antivirais/sangue , Infecções por Vírus Epstein-Barr/prevenção & controle , Herpesvirus Humano 4/fisiologia , Imunidade Humoral , Imunoglobulina G/sangue , Camundongos , Vesiculovirus/genética , Vacinas Virais/imunologia
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