Project description:Herpesviruses are frequently co-present with bacterial infection at multiple sites within the body, including the mouth, gut, and genitourinary tract. The detection of replicating virus in these compartments prompted investigation into the relationship between bacterial infection and Kaposi’s Sarcoma-associated Herpesvirus (KSHV) reactivation. Using a cell line latently infected with KSHV, we examined the ability of crude spent media containing metabolic products from periodontal and gut pathogens to reactivate KSHV. Upon incubation with crude spent media, KSHV was reactivated and we detected the up-regulation of viral early and late genes, linear viral genomes, and virions. Furthermore, KSHV reactivation was associated with global increases in histone H3 and histone H4 acetylation, consistent with viral expression. To explore the transcriptional consequences of spent media, we compared the gene expression changes following reactivation by P. gingivalis spent medium to those of two well-established pharmacological activators of KSHV reactivation, tetradecanolyl phorbol acetate and sodium butyrate. Microarray analyses revealed a unique gene expression signature with P. gingivalis-associated reactivation. Concurrent with KSHV reactivation, P. gingivalis spent medium increased the hypoxia response. Hypoxia was associated with effects on epigenetic regulators, including down-regulation of UHRF1, a modulator of DNA methylation. Our findings demonstrate that products secreted by oral bacteria not only stimulate a hypoxia response, but also result in global changes in epigenetic modifications and modifiers. These findings suggest that epigenetic changes induced by P. gingivalis underlie the KSHV reactivation pathway.
Project description:Epstein-Barr virus (EBV) uses a biphasic lifecycle of latency and lytic reactivation to infect >95% of adults worldwide. Despite its central role in EBV persistence and oncogenesis, much remains unknown about how EBV latency is maintained. We used a human genome-wide CRISPR/Cas9 screen to identify that the nuclear protein SFPQ was critical for latency. SFPQ supported expression of linker histone H1, which stabilizes nucleosomes and regulates nuclear architecture, but has not been previously implicated in EBV gene regulation. H1 occupied latent EBV genomes, including the immediate early gene BZLF1 promoter. Upon reactivation, SFPQ was sequestered into sub-nuclear puncta, and EBV genomic H1 occupancy diminished. Enforced H1 expression blocked EBV reactivation upon SFPQ knockout, confirming it as necessary downstream of SFPQ. SFPQ knockout triggered reactivation of EBV in B and epithelial cells as well as in Kaposi’s Sarcoma Associated Herpesvirus, suggesting a conserved gamma-herpesvirus role. These findings highlight SFPQ as a major regulator of H1 expression and EBV latency.
Project description:Purpose: Kaposi’s sarcoma associated-herpesvirus (KSHV) causes several hyperproliferative disorders, including Kaposi’s sarcoma, primary effusion lymphoma and multicentric Castleman’s disease. KSHV encodes for a number of microRNAs (miRNAs), and KSHV infection can affect the expression of cellular miRNAs. Hypoxia has been shown to induce KSHV reactivation, directly induce several KSHV lytic genes, and also induce the most abundant latent viral protein, LANA. Also, several KSHV proteins can stabilize and increase the cellular levels of hypoxia-inducible factor (HIF-1α). However, the degree to which hypoxic pathways are utilized by KSHV has yet to be determined. Methods: We investigated the interplay between hypoxia and KSHV infection by comparing the 31effects of hypoxia and KSHV infection on miRNA and mRNA expression, and by examining the 32effects of hypoxia on uninfected and KSHV-infected cells. This was accomplished using next-33generation sequencing (NGS), qRT-PCR, Taqman assays, and pathway analysis. Results: NGS analysis of human mRNAs revealed striking similarities (~34%) between the transcriptomic response to hypoxia and the transcriptomic response to KSHV infection. Additionally, hsa-miR-210, a key hypoxia-inducible miRNA with pro-angiogenic and anti-apoptotic properties, was found significantly up-regulated by both KSHV infection and hypoxia using Taqman assays. Finally, KSHV infected cells differed somewhat in their response to hypoxia compared to KSHV-uninfected controls. Conclusions: These results demonstrate that KSHV harnesses a part of the hypoxic cellular response and induces miR-210 up-regulation. The understanding of how these miRNAs, genes and pathways are regulated by HIF-1α and KSHV infection are essential to a better understanding of the biology of KSHV-associated diseases.
Project description:Purpose: Kaposi’s sarcoma associated-herpesvirus (KSHV) causes several hyperproliferative disorders, including Kaposi’s sarcoma, primary effusion lymphoma and multicentric Castleman’s disease. KSHV encodes for a number of microRNAs (miRNAs), and KSHV infection can affect the expression of cellular miRNAs. Hypoxia has been shown to induce KSHV reactivation, directly induce several KSHV lytic genes, and also induce the most abundant latent viral protein, LANA. Also, several KSHV proteins can stabilize and increase the cellular levels of hypoxia-inducible factor (HIF-1α). However, the degree to which hypoxic pathways are utilized by KSHV has yet to be determined. Methods: We investigated the interplay between hypoxia and KSHV infection by comparing the 31effects of hypoxia and KSHV infection on miRNA and mRNA expression, and by examining the 32effects of hypoxia on uninfected and KSHV-infected cells. This was accomplished using next-33generation sequencing (NGS), qRT-PCR, Taqman assays, and pathway analysis. Results: NGS analysis of human mRNAs revealed striking similarities (~34%) between the transcriptomic response to hypoxia and the transcriptomic response to KSHV infection. Additionally, hsa-miR-210, a key hypoxia-inducible miRNA with pro-angiogenic and anti-apoptotic properties, was found significantly up-regulated by both KSHV infection and hypoxia using Taqman assays. Finally, KSHV infected cells differed somewhat in their response to hypoxia compared to KSHV-uninfected controls. Conclusions: These results demonstrate that KSHV harnesses a part of the hypoxic cellular response and induces miR-210 up-regulation. The understanding of how these miRNAs, genes and pathways are regulated by HIF-1α and KSHV infection are essential to a better understanding of the biology of KSHV-associated diseases.
Project description:Kaposi’s Sarcoma Herpesvirus (KSHV) is the causative agent of Kaposi’s Sarcoma (KS) and isassociated with primary effusion lymphoma (PEL), multicentric Castleman’s disease (MCD) and two inflammatory diseases. KSHV-associated cancers are primarily associated with genes expressed during latency, while other pathologies are associated with lytic gene expression. The major lytic switch of the virus, RTA, interacts with cellular machinery to co-opt the host ubiquitin proteasome system to evade the immune response as well as activate the program of lytic replication. Through SILAC labeling, ubiquitin remnant enrichment and mass spectrometry, we have analyzed the RTA dependent ubiquitin-modified proteome. We identified RTA dependent changes in the populations of polyubiquitin chains, as well as changes in ubiquitinated proteins in both cells expressing RTA and naturally infected cells following lytic reactivation. We observed an enrichment of proteins that are also reported to be SUMOylated, suggesting that RTA, a SUMO targeting ubiquitin ligase, may function to alleviate a SUMO dependent block to lytic reactivation. RTA targeted substrates directly through a ubiquitin ligase domain dependent mechanism as well as indirectly through cellular ubiquitin ligases, including RAUL. Our ubiquitome analysis revealed an RTA dependent mechanism of immune evasion. We provide evidence of inhibition of TAP dependent peptide transport, resulting in decreased HLA complex stability. The results of this analysis increase our understanding of mechanisms governing the latent to lytic transition in addition to the identification of a novel RTA dependent mechanism of immune evasion.Kaposi’s Sarcoma Herpesvirus (KSHV) is the causative agent of Kaposi’s Sarcoma (KS) and is associated with primary effusion lymphoma (PEL), multicentric Castleman’s disease (MCD) and two inflammatory diseases. KSHV-associated cancers are primarily associated with genes expressed during latency, while other pathologies are associated with lytic gene expression. The major lytic switch of the virus, RTA, interacts with cellular machinery to co-opt the host ubiquitin proteasome system to evade the immune response as well as activate the program of lytic replication. Through SILAC labeling, ubiquitin remnant enrichment and mass spectrometry, we have analyzed the RTA dependent ubiquitin-modified proteome. We identified RTA dependent changes in the populations of polyubiquitin chains, as well as changes in ubiquitinated proteins in both cells expressing RTA and naturally infected cells following lytic reactivation. We observed an enrichment of proteins that are also reported to be SUMOylated, suggesting that RTA, a SUMO targeting ubiquitin ligase, may function to alleviate a SUMO dependent block to lytic reactivation. RTA targeted substrates directly through a ubiquitin ligase domain dependent mechanism as well as indirectly through cellular ubiquitin ligases, including RAUL. Our ubiquitome analysis revealed an RTA dependent mechanism of immune evasion. We provide evidence of inhibition of TAP dependent peptide transport, resulting in decreased HLA complex stability. The results of this analysis increase our understanding of mechanisms governing the latent to lytic transition in addition to the identification of a novel RTA dependent mechanism of immune evasion.
Project description:Enhancers play indispensable roles in cell proliferation and survival through spatiotemporally regulating gene transcription. In addition, active enhancers and super-enhancers often produce noncoding enhancer RNAs (eRNAs) that precisely control RNA polymerase II activity. Kaposi’s sarcoma-associated herpesvirus (KSHV) is a human oncogenic gamma-2 herpesvirus that causes Kaposi’s sarcoma and lymphoproliferative diseases of B-cell origin such as primary effusion lymphoma (PEL). It is well characterized that KSHV utilizes host epigenetic and nuclear machineries to control the switch between two life cycles, latency and lytic replication. However, how KSHV impacts the host epigenome at different stages of viral life cycle is not well understood. Using the analysis of global run-on sequencing (GRO-seq) and chromatin-immunoprecipitation sequencing (ChIP-seq), we profiled the dynamics of host transcriptional regulatory elements during latency and lytic replication of KSHV-infected PEL cells. This study showed that a number of critical host genes for KSHV latency, including MYC proto-oncogene, were under the control of super-enhancers and eRNAs that were globally repressed upon viral reactivation. A combination of circular chromosome conformation capture combined with sequencing (4C-seq), GRO-seq and ChIP-seq indicated that the eRNA-expressing super-enhance regions were located at downstream of the MYC gene in KSHV-infected PELs. Treatment of an epigenetic drug to block enhancer function or shRNA-mediated depletion of the eRNA expression significantly reduced MYC mRNA expression in KSHV-infected PELs. Finally, while cellular IRF4 acted upon the eRNAs and super-enhancers for MYC expression during latency, the KSHV viral IRF4 repressed cellular IRF4 expression upon reactivation, decreasing MYC expression and thereby, facilitating lytic replication. Taken together, these data suggest that KSHV acts as an epigenetic driver that modifies host epigenomic status by effectively regulating enhancer function upon reactivation.
Project description:Kaposi’s sarcoma-associated herpesvirus (KSHV) is a human oncogenic virus associated with various malignancies, including Kaposi’s sarcoma, primary effusion lymphoma, and multicentric Castleman’s disease. The expression of viral products is essential for initiating and sustaining KSHV-induced tumors. KSHV ORF57, a viral RNA-binding protein, plays a crucial role in regulating viral gene expression at the posttranscriptional level by promoting viral RNA stability, splicing, and translation. In addition, ORF57 dysregulates host gene expression to promote viral replications.
Project description:Kaposi’s sarcoma-associated herpesvirus (KSHV) causes the B cell malignancy primary effusion lymphoma (PEL). Here we performed mRNA sequencing to characterize the mRNA expression profile of the primary effusion lymhoma (PEL) cell line BC-1.
Project description:Kaposi’s Sarcoma-associated herpesvirus (KSHV) is the etiologic agent of Kaposi’s sarcoma, which is the most common cancer in acquired immune deficiency syndrome patients. Because KSHV has many viral proteins modulate many response, However, various effects by extracellular vesicles (EVs) during de novo KSHV infection has not been investigated to our best knowledge. We used microarrays to detail of gene expression underlying EV treatment and identified the up-regulated genes during treatment.