Project description:Epstein-Barr virus (EBV) reactivation in latently infected B cells is essential for persistent infection and B cell receptor (BCR) activation is a physiologically relevant stimulus for EBV reactivation. Post-translational modifications, such as phosphorylation and ubiquitination, are known to be regulated by antigen binding to BCR within minutes. However, a detailed understanding of the signaling alterations at later time when EBV is being actively replicated remains elusive. To gain insights into BCR activation-mediated reprogramming of the cellular environment in both Akata-BX1 (EBV+) and Akata-4E3 (EBV-) B cells, we utilized a 3-plex stable isotope labeling by amino acid in cell culture (SILAC)-based quantitative proteomic approach to monitor the dynamic changes of protein ubiquitination during the course of immunoglobulin G (IgG) cross-linking of BCRs. We observed temporal alterations in the level of ubiquitination on approximately 150 sites in both Akata-BX1 (EBV+) and Akata-4E3 (EBV-) B cells post-IgG cross-linking compared with no cross-linking controls, with the majority of protein ubiquitination down-regulated. Our analysis revealed that IgG cross-linking plays a major role in the regulation of protein ubiquitination in both EBV+ and EBV- B cells. Bioinformatic analyses of up-regulated ubiquitination events revealed significant enrichment of proteins involved in RNA processing. Among the down-regulated ubiquitination events are proteins enriched in apoptosis and the ubiquitin-proteasome pathway. The comparative and quantitative studies provide a foundation for further understanding how BCR activation regulates cellular protein ubiquitination and how EBV utilizes or subverts BCR engagement-mediated changes to facilitate viral replication.
Project description:RNAseq was used to identify host and EBV viral transcriptome changes in CHAF1B knock-out Akata EBV+ cells. CHAF1B KO Akata EBV+ cells were subjected to RNAseq analysis. The Akata EBV+ cells expressing control sgRNA was used as the control.
Project description:Analyze possible changes in the transcriptome of host cell line infected with a recombinant EBV virus. The recombinant virus is an Akata cell-derived NeoR EBV strain, previously used in PMID: 12969959
Project description:Transition of Akata Burkitt lymphoma (BL) cells from a malignant to nonmalignant phenotype upon loss of Epstein-Barr virus (EBV) genomes in vitro is evidence for a viral contribution to tumor maintenance despite the tightly restricted pattern of EBV gene expression in BL. Akata cells retaining virus manifest increased resistance to apoptosis under growth limiting conditions, although ambiguity exists regarding the exact mechanisms involved. By examining global cellular gene expression differences in Akata subclones that had either retained or lost EBV, we identified spermidine/spermine N1-acetyltransferase (SSAT), an inducible acetylating enzyme whose catabolism of polyamines affects both apoptosis and cell growth, as one of a limited number of cellular genes up-regulated upon loss of EBV. Keywords: Disease state analysis We used Affymetrix microarrays to examine variations in global gene expression between the paired EBV-positive (1B6) and EBV-negative (2A8) Akata Burkitt's lymphoma clones. EBV-negative Akata clones were generated by treatment with hydroxyurea, an inhibitor of ribonucleotide reductase that forced rapid loss of EBV episomes and compared to their EBV-positive counterparts. Logarithmically growing EBV-negative and positive Akata EBV clones were seeded at 2.5x10^5 cells/ml in RPMI1640 supplemented with 10% fetal bovine serum, 2mM glutamine, and 100units/ml penicillin/streptomycin. The next day, the cells were incubated for 4 hours in media containing 1% fetal bovine serum (low serum), 2mM glutatmine and 100units/ml penicillin/streptomycin to begin selection of the Akata tumor phenotype. The short incubation time was intended to minimize cell death and other potential downstream effects of low serum treatment, while at the same time initiating expression changes contributing to the tumorigenic phenotype.
Project description:To gain insights into how EBV latency is maintained, we performed a human genome-wide CRISPR screen in latently EBV-infected Burkitt lymphoma B-cells. Our analyses identified a network of host factors that repress EBV lytic reactivation, centered on the transcription factor MYC and including cohesins, FACT, STAGA and Mediator. RNAseq was used to identify host and viral transcriptome changes in P3HR-1 Burkitt lymphoma cells expressing control, smc1a, supt16h, med12, or tada2b sgRNAs. RNAseq was used to identify host and viral transcriptome changes in Akata EBV+ burkitt lymphoma cells expressing control or myc sgRNAs.
Project description:Idiopathic pulmonary fibrosis (IPF) is a refractory and lethal interstitial lung disease characterized by alveolar epithelial cells apoptosis, fibroblast proliferation and extra-cellular matrix proteins deposition. Epstein - Barr virus (EBV) has previously been localised to alveolar epithelial cells of IPF patients. In this study we utilised a microarray based differential gene expression analysis strategy to identify potential molecular drivers of EBV associated lung fibrosis. We employed an alveolar epithelial cell line infected with EBV (A-Akata). Lytic phase infection induced in the A-Akata cells by TPA/BA treatment resulted in increase of TGFbeta1 and TIEG1 mRNA expression. Treatment of the A-Akata cells with ganciclovir, resulted in a down regulation of both TIEG1 and TGFbeta1 expression, accompanied by a suppression of the EBV early response genes, Rta and Zta. This suppression of cell turnover mediators was correlated with an increase in cell activity index. To identify a possible role for Rta in driving apoptotic gene expression, we inhibited the Rta gene expression by silencing RNA, resulting in a decrease in TGFbeta1 and TIEG1 expression. This study identifies an apoptotic role of the EBV early response genes, as enhancer factors of TIEG1 and TGFbeta1 in EBV infected alveolar epithelial cells, potentially providing a possible mechanism for the role of EBV infection in pulmonary fibrosis. Keywords: EBV lytic phase infection, epithelial cell apoptosis, oligonucleotide array analysis
Project description:Epstein-Barr virus positive Burkitt's lymphoma cell line Akata (+) and it's EBV-depleted subclone Akata (-) were analyzed for human circRNA expression.
Project description:The oral cavity is the persistent reservoir for EBV with lifelong infection of resident epithelial and B cells. Infection of these cell types results in distinct EBV gene expression patterns that are regulated by epigenetic modifications involving DNA methylation and chromatin structure. Such regulation of EBV gene expression relies on viral manipulation of the host epigenetic machinery that may inadvertently result in long-lasting, oncogenic host epigenetic reprogramming. To test this hypothesis in the context of EBV infection of epithelial cells, we established a transient infection model to identify the epigenetic consequences after EBV infection of immortalized normal oral keratinocytes and subsequent viral loss. With mounting evidence that EBV can induce epigenetic alterations, we developed a transient infection model where a clonal derivative (designated cl1) from a human telomerase immortalized normal oral keratinocyte (NOK) cell line was infected with a recombinant Akata EBV carrying neomycin resistance and GfP cassette in place of the BXLF1 open reading frame. Infected cells were passaged ten times, and then selection pressure was removed for an additional ten passages to allow for viral loss. Three transiently-infected EBV-negative clones were identified by single cell cloning (designated cl1, cl3, cl4). Uninfected parental clone and cells transfected with PTRUF5 plasmid were passaged alongside the transiently-infected clones. The transcription profiles were analyzed using Affymetrix microarray U133Plus2.0 arrays in duplicate. NOK cells were single cell cloned (designated as cl1) and EBV infected by co-culture with a recombinant Akata EBV strain carrying neomcycin resistance and GFP expression cassette in place of EBV BXLF1. Cells were selected with 350 ug/ml G418. As a selection control, cells were transfected a plasmid carrying a neomycin resistance cassette. Cells were passaged 10 times with G418, followed by removal of selection pressure. After an additional 10 passages, cells were single cell cloned and the presence of EBV was determined by various methods. Three clones were identified as being EBV negative and said to be transiently infected. Uninfected parental and vector transfected cells were passaged in the same manner and also single cell cloned.
Project description:Transcriptional profiling of human mesenchymal stem cells comparing normoxic MSCs cells with hypoxic MSCs cells. Hypoxia may inhibit senescence of MSCs during expansion. Goal was to determine the effects of hypoxia on global MSCs gene expression.