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Sample records for kaposis sarcoma-associated herpesvirus

  1. Molecular piracy of Kaposi's sarcoma associated herpesvirus.

    PubMed

    Choi, J; Means, R E; Damania, B; Jung, J U

    2001-01-01

    Kaposi's Sarcoma associated Herpesvirus (KSHV) is the most recently discovered human tumor virus and is associated with the pathogenesis of Kaposi's sarcoma, primary effusion lymphoma, and Multicentric Casttleman's disease. KSHV contains numerous open reading frames with striking homology to cellular genes. These viral gene products play a variety of roles in KSHV-associated pathogenesis by disrupting cellular signal transduction pathways, which include interferon-mediated anti-viral responses, cytokine-regulated cell growth, apoptosis, and cell cycle control. In this review, we will attempt to cover our understanding of how viral proteins deregulate cellular signaling pathways, which ultimately contribute to the conversion of normal cells to cancerous cells.

  2. Kaposi sarcoma-associated herpesvirus: immunobiology, oncogenesis, and therapy.

    PubMed

    Dittmer, Dirk P; Damania, Blossom

    2016-09-01

    Kaposi sarcoma-associated herpesvirus (KSHV), also known as human herpesvirus 8, is the etiologic agent underlying Kaposi sarcoma, primary effusion lymphoma, and multicentric Castleman's disease. This human gammaherpesvirus was discovered in 1994 by Drs. Yuan Chang and Patrick Moore. Today, there are over five thousand publications on KSHV and its associated malignancies. In this article, we review recent and ongoing developments in the KSHV field, including molecular mechanisms of KSHV pathogenesis, clinical aspects of KSHV-associated diseases, and current treatments for cancers associated with this virus.

  3. Kaposi Sarcoma-associated Herpesvirus: mechanisms of oncogenesis.

    PubMed

    Schulz, Thomas F; Cesarman, Ethel

    2015-10-01

    Kaposi Sarcoma-associated Herpesvirus (KSHV, HHV8) causes three human malignancies, Kaposi Sarcoma (KS), an endothelial tumor, as well as Primary Effusion Lymphoma (PEL) and the plasma cell variant of Multicentric Castleman's Disease (MCD), two B-cell lymphoproliferative diseases. All three cancers occur primarily in the context of immune deficiency and/or HIV infection, but their pathogenesis differs. KS most likely results from the combined effects of an endotheliotropic virus with angiogenic properties and inflammatory stimuli and thus represents an interesting example of a cancer that arises in an inflammatory context. Viral and cellular angiogenic and inflammatory factors also play an important role in the pathogenesis of MCD. In contrast, PEL represents an autonomously growing malignancy that is, however, still dependent on the continuous presence of KSHV and the action of several KSHV proteins.

  4. Polyadenylylated nuclear RNA encoded by Kaposi sarcoma-associated herpesvirus.

    PubMed Central

    Sun, R; Lin, S F; Gradoville, L; Miller, G

    1996-01-01

    A newly recognized gamma herpesvirus known as Kaposi sarcoma-associated herpesvirus (KSHV) or human herpesvirus 8 (HHV8) is present in Kaposi sarcomas and body-cavity-based lymphomas. Here we identify a novel abundant 1.2-kb RNA, polyadenylated nuclear RNA (PAN RNA), encoded by the virus. The majority of cDNAs produced from poly(A)-selected RNA isolated from a human body cavity lymphoma cell line 48 hr after butyrate induction of KSHV lytic replication represented PAN RNA. Within PAN RNA were two 9 and 16 nt stretches with 89% and 94% identity to U1 RNA. A third stretch of 14 nt was 93% complementary to U1. The 5' upstream region of PAN RNA contained both proximal and distal sequence elements characteristic of regulatory regions of U snRNAs, whereas the 3' end was polyadenylylated. PAN RNA was transcribed by RNA polymerase II, lacked a trimethylguanosine cap, and did not associate with polyribosomes. PAN RNA formed a speckled pattern in the nucleus typical of U snRNAs and colocalized with Sm protein. Therefore, PAN represents a new type of RNA, possessing features of both U snRNA and mRNA. Images Fig. 2 Fig. 3 Fig. 4 PMID:8876232

  5. The role of Kaposi sarcoma-associated herpesvirus in the pathogenesis of Kaposi sarcoma.

    PubMed

    Gramolelli, Silvia; Schulz, Thomas F

    2015-01-01

    Kaposi sarcoma (KS) is an unusual vascular tumour caused by an oncogenic-herpesvirus, Kaposi sarcoma-associated herpesvirus (KSHV), also known as human herpesvirus 8 (HHV 8). KS lesions are characterized by an abundant inflammatory infiltrate, the presence of KSHV-infected endothelial cells that show signs of aberrant differentiation, as well as faulty angiogenesis/ vascularization. Here we discuss the molecular mechanisms that lead to the development of these histological features of KS, with an emphasis on the viral proteins that are responsible for their development.

  6. Kaposi's Sarcoma-Associated Herpesvirus Encodes a Viral Deubiquitinase▿

    PubMed Central

    González, Carlos M.; Wang, Ling; Damania, Blossom

    2009-01-01

    Kaposi's sarcoma-associated herpesvirus (KSHV) is etiologically linked to Kaposi's sarcoma, primary effusion lymphomas, and multicentric Castleman's disease. Like other herpesviruses, KSHV can exist in either a lytic or a latent phase during its life cycle. We report that the lytic protein encoded by KSHV open reading frame 64 (Orf64) is a viral deubiquitinase (DUB) enzyme capable of deubiquitinating cellular proteins in vitro and in vivo. Orf64 DUB activity is effective against lysine 48 (K48)- and lysine 63 (K63)-linked ubiquitin chains. Thus, KSHV Orf64 is a viral DUB that does not show specificity toward K48 or K63 ubiquitin linkages. Orf64 DUB activity lies within the first 205 residues of the protein, and deubiquitination is dependent on a cysteine at position 29, since mutation of this residue ablated this activity. Cell fractionation studies revealed that the N terminus and the full-length protein localized to both the nuclear and cytoplasmic compartments. The function of Orf64 was tested by short interfering RNA (siRNA) knockdown studies on latently infected cells that were induced into lytic replication. We found that depletion of Orf64 by siRNA resulted in decreased viral lytic transcription and lytic protein expression. These experiments indicate that Orf64 plays a role in KSHV lytic replication. PMID:19640989

  7. Molecular virology of Kaposi's sarcoma-associated herpesvirus.

    PubMed Central

    Moore, P S; Chang, Y

    2001-01-01

    Kaposi's sarcoma-associated herpesvirus (KSHV), the most recently discovered human tumour virus, is the causative agent of Kaposi's sarcoma, primary effusion lymphoma and some forms of Castleman's disease. KSHV is a rhadinovirus, and like other rhadinoviruses, it has an extensive array of regulatory genes obtained from the host cell genome. These pirated KSHV proteins include homologues to cellular CD21, three different beta-chemokines, IL-6, BCL-2, several different interferon regulatory factor homologues, Fas-ligand ICE inhibitory protein (FLIP), cyclin D and a G-protein-coupled receptor, as well as DNA synthetic enzymes including thymidylate synthase, dihydrofolate reductase, DNA polymerase, thymidine kinase and ribonucleotide reductases. Despite marked differences between KSHV and Epstein-Barr virus, both viruses target many of the same cellular pathways, but use different strategies to achieve the same effects. KSHV proteins have been identified which inhibit cell-cycle regulation checkpoints, apoptosis control mechanisms and the immune response regulatory machinery. Inhibition of these cellular regulatory networks app ears to be a defensive means of allowing the virus to escape from innate antiviral immune responses. However, due to the overlapping nature of innate immune and tumour-suppressor pathways, inhibition of these regulatory networks can lead to unregulated cell proliferation and may contribute to virus-induced tumorigenesis. PMID:11313008

  8. RNAs in the virion of Kaposi's sarcoma-associated herpesvirus.

    PubMed

    Bechtel, Jill; Grundhoff, Adam; Ganem, Don

    2005-08-01

    De novo infection of cultured cells with Kaposi's sarcoma-associated herpesvirus (KSHV) typically results in a latent infection. Recently, however, it has been reported that a subset of lytic mRNAs can be detected in cells shortly after KSHV infection; this expression is transient and eventually subsides, leading to latent infection (H. H. Krishnan et al., J. Virol 78:3601-3620, 2004). Since it has been shown that viral RNAs can be packaged into other herpesvirus virions, we sought to determine if KSHV virions contained RNAs and, if so, whether these RNAs contributed to the pool of lytic transcripts detected immediately after infection. Using DNA microarray, reverse transcription (RT)-PCR, and Northern blotting analyses, we identified 11 virally encoded RNAs in KSHV virions. These corresponded in size to the full-length mRNAs found in cytoplasmic RNA, and at least one was directly demonstrated to be translated upon infection in the presence of actinomycin D. Ten of these RNAs correspond to transcripts reported by Krishnan et al. at early times of infection, representing ca. 30% of such RNAs. Thus, import of RNAs in virions can account for some but not all of the early-appearing lytic transcripts. Quantitative RT-PCR analysis of infected-cell RNA demonstrated that most of the virion RNAs were very abundant at late times of infection, consistent with nonspecific incorporation during budding. However, the intracellular levels of one virion mRNA, encoding the viral protease, were much lower than those of transcripts not packaged in the virus particle, strongly suggesting that it may be incorporated by a specific mechanism.

  9. Kinetics of Kaposi's sarcoma-associated herpesvirus gene expression.

    PubMed

    Sun, R; Lin, S F; Staskus, K; Gradoville, L; Grogan, E; Haase, A; Miller, G

    1999-03-01

    Herpesvirus gene expression can be classified into four distinct kinetic stages: latent, immediate early, early, and late. Here we characterize the kinetic class of a group of 16 Kaposi's sarcoma-associated herpesvirus (KSHV)/human herpesvirus 8 genes in a cultured primary effusion cell line and examine the expression of a subset of these genes in KS biopsies. Expression of two latent genes, LANA and vFLIP, was constitutive and was not induced by chemicals that induce the lytic cycle in primary effusion lymphoma (PEL) cell lines. An immediate-early gene, Rta (open reading frame 50 [ORF50]), was induced within 4 h of the addition of n-butyrate, and its 3.6-kb mRNA was resistant to inhibition by cycloheximide. Early genes, including K3 and K5 that are homologues of the "immediate-early" gene of bovine herpesvirus 4, K8 that is a positional homologue of Epstein-Barr virus BZLF1, vMIP II, vIL-6, and polyadenylated nuclear (PAN) RNA, appeared 8 to 13 h after chemical induction. A second group of early genes that were slightly delayed in their appearance included viral DHFR, thymidylate synthase, vMIP I, G protein-coupled receptor, K12, vBcl2, and a lytic transcript that overlapped LANA. The transcript of sVCA (ORF65), a late gene whose expression was abolished by Phosphonoacetic acid, an inhibitor of KSHV DNA replication, did not appear until 30 h after induction. Single-cell assays indicated that the induction of lytic cycle transcripts resulted from the recruitment of additional cells into the lytic cycle. In situ hybridization of KS biopsies showed that about 3% of spindle-shaped tumor cells expressed Rta, ORF K8, vIL-6, vMIP I, vBcl-2, PAN RNA, and sVCA. Our study shows that several KSHV-encoded homologues of cellular cytokines, chemokines, and antiapoptotic factors are expressed during the viral lytic cycle in PEL cell lines and in KS biopsies. The lytic cycle of KSHV, probably under the initial control of the KSHV/Rta gene, may directly contribute to tumor

  10. Treatment of Kaposi Sarcoma-Associated Herpesvirus-Associated Cancers

    PubMed Central

    Dittmer, Dirk P.; Richards, Kristy L.; Damania, Blossom

    2012-01-01

    Kaposi sarcoma (KS) is the most frequent AIDS-defining cancer worldwide. KS-associated herpesvirus (KSHV) is the etiological agent of KS, and the virus is also associated with two lymphoproliferative diseases. Both KS and KSHV-associated lymphomas, are cancers of unique molecular composition. They represent a challenge for cancer treatment and an opportunity to identify new mechanisms of transformation. Here, we review the current clinical insights into KSHV-associated cancers and discuss scientific insights into the pathobiology of KS, primary effusion lymphoma, and multicentric Castleman’s disease. PMID:22529843

  11. Epidemiology and pathogenesis of Kaposi's sarcoma-associated herpesvirus.

    PubMed Central

    Boshoff, C; Weiss, R A

    2001-01-01

    Kaposi's sarcoma (KS) occurs in Europe and the Mediterranean countries (classic KS) and Africa (endemic KS), immunosuppressed patients (iatrogenic or post-transplant KS) and those with acquired immune deficiency syndrome (AIDS), especially among those who acquired human immunodeficiency virus sexually (AIDS-KS). KS-associated herpesvirus (KSHV or HHV-8) is unusual among herpesviruses in having a restricted geographical distribution. Like KS, which it induces in immunosuppressed or elderly people, the virus is prevalent in Africa, in Mediterranean countries, among Jews and Arabs and certain Amerindians. Distinct KSHV genotypes occur in different parts of the world, but have not been identified as having a differential pathogenesis. KSHV is aetiologically linked to three distinct neoplasms: (i) KS, (ii) primary effusion lymphoma, and (iii) plasmablastic multicentric Castleman's disease. The histogenesis, clonality and pathology of the tumours are described, together with the epidemiology and possible modes of transmission of the virus. PMID:11313009

  12. Construction of a lytically replicating Kaposi's sarcoma-associated herpesvirus.

    PubMed

    Budt, Matthias; Hristozova, Tsvetana; Hille, Georg; Berger, Katrin; Brune, Wolfram

    2011-10-01

    Karposi's sarcoma-associated herpesvirus (KSHV) is found predominantly in a latent state in most cell types, impeding investigations of the lytic replication cycle. Here, we engineered the cloned KSHV genome, bacterial artificial chromosome 36 (BAC36), to enforce constitutive expression of the main lytic switch regulator, the replication and transcription activator (RTA) (open reading frame 50 [ORF50]). The resulting virus, KSHV-lyt, activated by default the lytic cycle and replicated to high titers in various cells. Using KSHV-lyt, we showed that ORF33 (encoding a tegument protein) is essential for lytic KSHV replication in cell culture, but ORF73 (encoding the latent nuclear antigen [LANA]) is not. Thus, KSHV-lyt should be highly useful to study viral gene function during lytic replication.

  13. Comparative analysis of the transforming mechanisms of Epstein-Barr virus, Kaposi's sarcoma-associated herpesvirus, and Herpesvirus saimiri.

    PubMed

    Damania, B; Jung, J U

    2001-01-01

    Members of the gamma herpesvirus family include the lymphocryptoviruses (gamma-1 herpesviruses) and the rhadinoviruses (gamma-2 herpesviruses). Gammaherpesvirinae uniformly establish long-term, latent, reactivatable infection of lymphocytes, and several members of the gamma herpesviruses are associated with lymphoproliferative diseases. Epstein-Barr virus is a lymphocryptovirus, whereas Kaposi sarcoma-associated herpesvirus and Herpesvirus saimiri are members of the rhadinovirus family. Genes encoded by these viruses are involved in a diverse array of cellular signaling pathways. This review attempts to cover our understanding of how viral proteins deregulate cellular signaling pathways that ultimately contribute to the conversion of normal cells to cancerous cells.

  14. Spectrum of Kaposi's Sarcoma-Associated Herpesvirus, or Human Herpesvirus 8, Diseases

    PubMed Central

    Ablashi, Dharam V.; Chatlynne, Louise G.; Whitman, Jr., James E.; Cesarman, Ethel

    2002-01-01

    Human herpesvirus 8 (HHV-8), also known as Kaposi's sarcoma-associated herpesvirus (KSHV), discovered in 1994, is a human rhadinovirus (gamma-2 herpesvirus). Unlike other human herpesviruses (herpes simplex virus, Epstein-Barr virus, varicella-zoster virus, cytomegalovirus, HHV-6, and HHV-7), it is not widespread in the general population and has many unique proteins. HHV-8 is strongly associated with all subtypes of Kaposi's sarcoma (KS), multicentric Castleman's disease, and a rare form of B-cell lymphoma, primary effusion lymphoma. In addition, HHV-8 DNA sequences have been found in association with other diseases, but the role of the virus in these diseases is largely unconfirmed and remains controversial. The seroprevalence of HHV-8, based on detection of latent and lytic proteins, is 2 to 5% in healthy donors except in certain geographic areas where the virus is endemic, 80 to 95% in classic KS patients, and 40 to 50% in HIV-1 patients without KS. This virus can be transmitted both sexually and through body fluids (e.g., saliva and blood). HHV-8 is a transforming virus, as evidenced by its presence in human malignancies, by the in vitro transforming properties of several of its viral genes, and by its ability to transform some primary cells in culture. It is not, however, sufficient for transformation, and other cofactors such as immunosuppressive cytokines are involved in the development of HHV-8-associated malignancies. In this article, we review the biology, molecular virology, epidemiology, transmission, detection methods, pathogenesis, and antiviral therapy of this newly discovered human herpesvirus. PMID:12097251

  15. Kaposi's sarcoma-associated herpesvirus K7 modulates Rubicon-mediated inhibition of autophagosome maturation.

    PubMed

    Liang, Qiming; Chang, Brian; Brulois, Kevin F; Castro, Kamilah; Min, Chan-Ki; Rodgers, Mary A; Shi, Mude; Ge, Jianning; Feng, Pinghui; Oh, Byung-Ha; Jung, Jae U

    2013-11-01

    Autophagy is an important innate safeguard mechanism for protecting an organism against invasion by pathogens. We have previously discovered that Kaposi's sarcoma-associated herpesvirus (KSHV) evades this host defense through tight suppression of autophagy by targeting multiple steps of autophagy signal transduction. Here, we report that KSHV K7 protein interacts with Rubicon autophagy protein and inhibits the autophagosome maturation step by blocking Vps34 enzymatic activity, further highlighting how KSHV deregulates autophagy-mediated host immunity for its life cycle.

  16. Transmissible Kaposi's sarcoma-associated herpesvirus (human herpesvirus 8) in saliva of men with a history of Kaposi's sarcoma.

    PubMed Central

    Vieira, J; Huang, M L; Koelle, D M; Corey, L

    1997-01-01

    We have evaluated the physical state and infectious nature of Kaposi's sarcoma-associated herpesvirus (KSHV) in the saliva of nine persons with past or current Kaposi's sarcoma (KS). KSHV DNA in saliva had the physical characteristics of DNA present in virions. Inoculation of 293 cells with cell-free saliva fluid resulted in the persistence of KSHV DNA in culture for at least 13 passages of the cells. The addition of tetradecanoyl phorbol acetate to KSHV-infected 293 cells led to increased viral DNA. Two virus-specific RNAs were detected by reverse transcriptase PCR in 293 cells infected with cell-free saliva fluid and in cells present in saliva from subjects with KSHV salivary shedding. These results indicate that infectious KSHV can be present in saliva of patients with KS. PMID:9261440

  17. Comparative Pathobiology of Kaposi Sarcoma-associated Herpesvirus and Related Primate Rhadinoviruses

    PubMed Central

    Westmoreland, Susan V; Mansfield, Keith G

    2008-01-01

    With the emergence of the AIDS epidemic over the last 2 decades and the more recent identification of Kaposi sarcoma-associated herpesvirus (KSHV, Human herpesvirus 8), the genera of rhadinoviruses have gained importance as a family of viruses with oncogenic potential. First recognized in New World primates more than 30 y ago, the rhadinoviruses Saimiriine herpesvirus 2 and Ateline herpesvirus 2 have well-described transforming capabilities. Recently several new species-specific rhadinoviruses of Old World primates have been described, including retroperitoneal fibromatosis herpesvirus and rhesus rhadinovirus (Cercopithecine herpesvirus 17). Molecular analysis of these viruses has elucidated several functionally conserved genes and properties shared with KSHV involved in cellular proliferation, transformation, and immune evasion that facilitate the oncogenic potential of these viruses. This review examines the comparative pathobiology of KSHV, discusses the role of macaque rhadinoviruses as models of human disease, and outlines the derivation of specific pathogen-free animals. PMID:19793454

  18. Epigenetic Landscape of Kaposi's Sarcoma-Associated Herpesvirus Genome in Classic Kaposi's Sarcoma Tissues

    PubMed Central

    Wang, Xiaodong; Yang, Lei; Robertson, Erle S.; Lan, Ke

    2017-01-01

    Kaposi's sarcoma-associated herpesvirus (KSHV) is etiologically related to Kaposi's sarcoma (KS), primary effusion lymphoma (PEL) and multicentric Castleman's disease (MCD). It typically displays two different phases in its life cycle, the default latency and occasional lytic replication. The epigenetic modifications are thought to determine the fate of KSHV infection. Previous studies elegantly depicted epigenetic landscape of latent viral genome in in vitro cell culture systems. However, the physiologically relevant scenario in clinical KS tissue samples is unclear. In the present study, we established a protocol of ChIP-Seq for clinical KS tissue samples and mapped out the epigenetic landscape of KSHV genome in classic KS tissues. We examined AcH3 and H3K27me3 histone modifications on KSHV genome, as well as the genome-wide binding sites of latency associated nuclear antigen (LANA). Our results demonstrated that the enriched AcH3 was mainly restricted at latent locus while H3K27me3 was widespread on KSHV genome in classic KS tissues. The epigenetic landscape at the region of vIRF3 gene confirmed its silenced state in KS tissues. Meanwhile, the abundant enrichment of LANA at the terminal repeat (TR) region was also validated in the classic KS tissues, however, different LANA binding sites were observed on the host genome. Furthermore, we verified the histone modifications by ChIP-qPCR and found the dominant repressive H3K27me3 at the promoter region of replication and transcription activator (RTA) in classic KS tissues. Intriguingly, we found that the TR region in classic KS tissues was lacking in AcH3 histone modifications. These data now established the epigenetic landscape of KSHV genome in classic KS tissues, which provides new insights for understanding KSHV epigenetics and pathogenesis. PMID:28118409

  19. Kaposi's sarcoma-associated herpesvirus infection of bone marrow dendritic cells from multiple myeloma patients.

    PubMed

    Rettig, M B; Ma, H J; Vescio, R A; Põld, M; Schiller, G; Belson, D; Savage, A; Nishikubo, C; Wu, C; Fraser, J; Said, J W; Berenson, J R

    1997-06-20

    Kaposi's sarcoma-associated herpesvirus (KSHV) was found in the bone marrow dendritic cells of multiple myeloma patients but not in malignant plasma cells or bone marrow dendritic cells from normal individuals or patients with other malignancies. In addition the virus was detected in the bone marrow dendritic cells from two out of eight patients with monoclonal gammopathy of undetermined significance (MGUS), a precursor to myeloma. Viral interleukin-6, the human homolog of which is a growth factor for myeloma, was found to be transcribed in the myeloma bone marrow dendritic cells. KSHV may be required for transformation from MGUS to myeloma and perpetuate the growth of malignant plasma cells.

  20. Kaposi's Sarcoma-Associated Herpesvirus Latency Locus Compensates for Interleukin-6 in Initial B Cell Activation.

    PubMed

    Sin, Sang-Hoon; Kang, Sun Ah; Kim, Yongbaek; Eason, Anthony; Tan, Kelly; An, Hyowon; Dittmer, Dirk P

    2015-12-09

    Interleukin 6 (IL-6) is considered a proliferation and survival factor for B cells. To assess the role of IL-6 in Kaposi sarcoma-associated herpesvirus (KSHV) latency, KSHV latency locus-transgenic mice (referred to as latency mice) lacking IL-6 were evaluated. IL-6(-/-) latency mice had the same phenotypes as the latency mice, i.e., increased frequency of marginal zone B cells, hyperplasia, and hyperglobulinemia, indicating that the KSHV latency locus, which includes all viral microRNAs (miRNAs), can compensate for lack of IL-6 in premalignant B cell activation.

  1. Molecular piracy: manipulation of the ubiquitin system by Kaposi's sarcoma-associated herpesvirus.

    PubMed

    Fujimuro, Masahiro; Hayward, S Diane; Yokosawa, Hideyoshi

    2007-01-01

    Ubiquitination, one of several post-translational protein modifications, plays a key role in the regulation of cellular events, including protein degradation, signal transduction, endocytosis, protein trafficking, apoptosis and immune responses. Ubiquitin attachment at the lysine residue of cellular factors acts as a signal for endocytosis and rapid degradation by the 26S proteasome. It has recently been observed that viruses, especially oncogenic herpesviruses, utilise molecular piracy by encoding their own proteins to interfere with regulation of cell signalling. Kaposi's sarcoma- associated herpesvirus (KSHV) manipulates the ubiquitin system to facilitate cell proliferation, anti-apoptosis and evasion from immunity. In this review, we will describe the strategies used by KSHV at distinct stages of the viral life-cycle to control the ubiquitin system and promote oncogenesis and viral persistence.

  2. Structural map of Kaposi sarcoma-associated herpesvirus RNA provides clues to molecular interactions | Center for Cancer Research

    Cancer.gov

    Scientists from CCR have generated a comprehensive structural map of Kaposi sarcoma-associated herpesvirus polyadenylated nuclear (PAN) RNA, a long non-coding RNA that helps the virus evade detection by its host’s immune system. The findings open new oppportunites to study the life cycle of this cancer-causing virus.  Learn more...

  3. ARID3B: a Novel Regulator of the Kaposi's Sarcoma-Associated Herpesvirus Lytic Cycle

    PubMed Central

    Wood, Jennifer J.; Boyne, James R.; Paulus, Christina; Jackson, Brian R.; Nevels, Michael M.

    2016-01-01

    ABSTRACT Kaposi's sarcoma-associated herpesvirus (KSHV) is the causative agent of commonly fatal malignancies of immunocompromised individuals, including primary effusion lymphoma (PEL) and Kaposi's sarcoma (KS). A hallmark of all herpesviruses is their biphasic life cycle—viral latency and the productive lytic cycle—and it is well established that reactivation of the KSHV lytic cycle is associated with KS pathogenesis. Therefore, a thorough appreciation of the mechanisms that govern reactivation is required to better understand disease progression. The viral protein replication and transcription activator (RTA) is the KSHV lytic switch protein due to its ability to drive the expression of various lytic genes, leading to reactivation of the entire lytic cycle. While the mechanisms for activating lytic gene expression have received much attention, how RTA impacts cellular function is less well understood. To address this, we developed a cell line with doxycycline-inducible RTA expression and applied stable isotope labeling of amino acids in cell culture (SILAC)-based quantitative proteomics. Using this methodology, we have identified a novel cellular protein (AT-rich interacting domain containing 3B [ARID3B]) whose expression was enhanced by RTA and that relocalized to replication compartments upon lytic reactivation. We also show that small interfering RNA (siRNA) knockdown or overexpression of ARID3B led to an enhancement or inhibition of lytic reactivation, respectively. Furthermore, DNA affinity and chromatin immunoprecipitation assays demonstrated that ARID3B specifically interacts with A/T-rich elements in the KSHV origin of lytic replication (oriLyt), and this was dependent on lytic cycle reactivation. Therefore, we have identified a novel cellular protein whose expression is enhanced by KSHV RTA with the ability to inhibit KSHV reactivation. IMPORTANCE Kaposi's sarcoma-associated herpesvirus (KSHV) is the causative agent of fatal malignancies of

  4. A negative element involved in Kaposi's sarcoma-associated herpesvirus-encoded ORF11 gene expression

    SciTech Connect

    Chen, Lei

    2009-01-01

    The ORF11 of the Kaposi's sarcoma-associated herpesvirus (KSHV) is a lytic viral gene with delayed-early expression kinetics. How the ORF11 gene expression is regulated in the KSHV lytic cascade is largely unknown. Here we report that the deletion of the KSHV viral IL-6 gene from the viral genome leads to deregulated ORF11 gene expression. The KSHV-encoded viral IL-6 protein was found not to be essentially involved in the regulation of ORF11, suggesting a potential transcriptional cis-regulation. A negative element was identified downstream of the ORF11 gene, which suppresses the ORF11 basal promoter activity in a position-independent manner.

  5. Multiple defects, including premature apoptosis, prevent Kaposi's sarcoma-associated herpesvirus replication in murine cells.

    PubMed

    Austgen, Kathryn; Oakes, Scott A; Ganem, Don

    2012-02-01

    The development of a mouse model for Kaposi's sarcoma-associated herpesvirus (KSHV) infection has been impeded by the limited host range of the virus. Here, we have examined the molecular basis of this host range restriction. KSHV efficiently enters murine cells and establishes latency. However, ectopic expression of the lytic switch protein RTA (replication and transcription activator) in these cells induces little viral gene expression and no virus production. Upon treatment with histone deacetylase inhibitors, KSHV-infected murine cells display more extensive but aberrant viral transcription and do not support either viral DNA synthesis or the production of infectious virions. These aberrantly infected cells also display markedly enhanced apoptosis. Genetic ablation of the mitochondrial apoptotic pathway in these cells prolongs their survival and permits viral DNA replication but does not rescue the generation of virions. We conclude that multiple defects, both prior to and following DNA synthesis, restrict lytic KSHV infection in murine cells.

  6. Kaposi's sarcoma-associated herpesvirus stably clusters its genomes across generations to maintain itself extrachromosomally.

    PubMed

    Chiu, Ya-Fang; Sugden, Arthur U; Fox, Kathryn; Hayes, Mitchell; Sugden, Bill

    2017-09-04

    Genetic elements that replicate extrachromosomally are rare in mammals; however, several human tumor viruses, including the papillomaviruses and the gammaherpesviruses, maintain their plasmid genomes by tethering them to cellular chromosomes. We have uncovered an unprecedented mechanism of viral replication: Kaposi's sarcoma-associated herpesvirus (KSHV) stably clusters its genomes across generations to maintain itself extrachromosomally. To identify and characterize this mechanism, we developed two complementary, independent approaches: live-cell imaging and a predictive computational model. The clustering of KSHV requires the viral protein, LANA1, to bind viral genomes to nucleosomes arrayed on both cellular and viral DNA. Clustering affects both viral partitioning and viral genome numbers of KSHV. The clustering of KSHV plasmids provides it with an effective evolutionary strategy to rapidly increase copy numbers of genomes per cell at the expense of the total numbers of cells infected. © 2017 Chiu et al.

  7. Myc is required for the maintenance of Kaposi's sarcoma-associated herpesvirus latency.

    PubMed

    Li, Xudong; Chen, Shijia; Feng, Jun; Deng, Hongyu; Sun, Ren

    2010-09-01

    Myc is deregulated by Kaposi's sarcoma-associated herpesvirus (KSHV) latent proteins, but its role in KSHV latency is not clear. We found that Myc knockdown with RNA interference (RNAi) induced KSHV reactivation and increased the protein and mRNA levels of RTA, a key viral regulator of KSHV reactivation. Myc knockdown increased, whereas Myc overexpression inhibited, RTA promoter activity. KSHV reactivation and the activation of the RTA promoter induced by Myc depletion were inhibited by c-Jun N-terminal kinase (JNK) and p38 inhibitors but not by a MEK1 inhibitor. Myc knockdown inhibited primary effusion lymphoma (PEL) cell proliferation through inducing apoptosis and G(1) cell cycle arrest. Thus, Myc may be a key cellular node coupling cellular transformation and KSHV latency.

  8. Kaposi's sarcoma-associated herpesvirus infection of blood endothelial cells induces lymphatic differentiation.

    PubMed

    Carroll, Patrick A; Brazeau, Elizabeth; Lagunoff, Michael

    2004-10-10

    Kaposi's sarcoma-associated herpesvirus (KSHV) is necessary for KS, a highly vascularized tumor predominated by endothelial-derived spindle cells that express markers of lymphatic endothelium. Following KSHV infection of TIME cells, an immortalized human dermal microvascular endothelial cell (DMVEC) line, expression of many genes specific to lymphatic endothelium, including VEGFR3, podoplanin, LYVE-1, and Prox-1, is significantly increased. Increases in VEGFR3 and podoplanin protein are also demonstrated following latent infection. Examination of cytokine secretion showed that KSHV infection significantly induces hIL-6 while strongly inhibiting secretion of IL-8, a gene product that is decreased by differentiation of blood to lymphatic endothelial cells. These studies support the hypotheses that latent KSHV infection of blood endothelial cells drives their differentiation to lymphatic endothelial cells.

  9. Kaposi's Sarcoma-Associated Herpesvirus Infection of Neurons in HIV-Positive Patients.

    PubMed

    Tso, For Yue; Sawyer, Ashley; Kwon, Eun Hee; Mudenda, Victor; Langford, Dianne; Zhou, You; West, John; Wood, Charles

    2017-06-15

    Kaposi's sarcoma-associated herpesvirus (KSHV) is the causative agent of Kaposi sarcoma (KS), one of the leading cancers in human immunodeficiency virus (HIV)-infected patients in Zambia. KSHV was detected in the human central nervous system (CNS) by polymerase chain reaction (PCR) analysis, but tissue location and cell tropism for KSHV infection has not been established. Given the neurotropism exhibited by other herpesviruses and the frequent coinfection of HIV-positive individuals by KSHV, we sought to determine whether the central nervous system (CNS) can be infected by KSHV in HIV-positive Zambian individuals. Postmortem brain tissue specimens were collected from individuals coinfected with KSHV and HIV. PCR and Southern blots were performed on DNA extracted from the brain tissue specimens to verify KSHV infection. Immunohistochemical analysis and immunofluorescent microscopy were used to localize and identify KSHV-infected cells. Tropism was further established by in vitro infection of primary human neurons with rKSHV.219. KSHV DNA was detected in the CNS from 4 of 11 HIV-positive individuals. Immunohistochemical analysis and immunofluorescent microscopy demonstrated that KSHV infected neurons and oligodendrocytes in parenchymal brain tissues. KSHV infection of neurons was confirmed by in vitro infection of primary human neurons with rKSHV.219. Our study showed that KSHV infects human CNS-resident cells, primarily neurons, in HIV-positive Zambian individuals.

  10. Multiplexed colorimetric detection of Kaposi's sarcoma associated herpesvirus and Bartonella DNA using gold and silver nanoparticles

    NASA Astrophysics Data System (ADS)

    Mancuso, Matthew; Jiang, Li; Cesarman, Ethel; Erickson, David

    2013-01-01

    Kaposi's sarcoma (KS) is an infectious cancer occurring most commonly in human immunodeficiency virus (HIV) positive patients and in endemic regions, such as Sub-Saharan Africa, where KS is among the top four most prevalent cancers. The cause of KS is the Kaposi's sarcoma-associated herpesvirus (KSHV, also called HHV-8), an oncogenic herpesvirus that while routinely diagnosed in developed nations, provides challenges to developing world medical providers and point-of-care detection. A major challenge in the diagnosis of KS is the existence of a number of other diseases with similar clinical presentation and histopathological features, requiring the detection of KSHV in a biopsy sample. In this work we develop an answer to this challenge by creating a multiplexed one-pot detection system for KSHV DNA and DNA from a frequently confounding disease, bacillary angiomatosis. Gold and silver nanoparticle aggregation reactions are tuned for each target and a multi-color change system is developed capable of detecting both targets down to levels between 1 nM and 2 nM. The system developed here could later be integrated with microfluidic sample processing to create a final device capable of solving the two major challenges in point-of-care KS detection.

  11. The HIV protease inhibitor nelfinavir inhibits Kaposi's sarcoma-associated herpesvirus replication in vitro.

    PubMed

    Gantt, Soren; Carlsson, Jacquelyn; Ikoma, Minako; Gachelet, Eliora; Gray, Matthew; Geballe, Adam P; Corey, Lawrence; Casper, Corey; Lagunoff, Michael; Vieira, Jeffrey

    2011-06-01

    Kaposi's sarcoma (KS) is the most common HIV-associated cancer worldwide and is associated with high levels of morbidity and mortality in some regions. Antiretroviral (ARV) combination regimens have had mixed results for KS progression and resolution. Anecdotal case reports suggest that protease inhibitors (PIs) may have effects against KS that are independent of their effect on HIV infection. As such, we evaluated whether PIs or other ARVs directly inhibit replication of Kaposi's sarcoma-associated herpesvirus (KSHV), the gammaherpesvirus that causes KS. Among a broad panel of ARVs tested, only the PI nelfinavir consistently displayed potent inhibitory activity against KSHV in vitro as demonstrated by an efficient quantitative assay for infectious KSHV using a recombinant virus, rKSHV.294, which expresses the secreted alkaline phosphatase. This inhibitory activity of nelfinavir against KSHV replication was confirmed using virus derived from a second primary effusion lymphoma cell line. Nelfinavir was similarly found to inhibit in vitro replication of an alphaherpesvirus (herpes simplex virus) and a betaherpesvirus (human cytomegalovirus). No activity was observed with nelfinavir against vaccinia virus or adenovirus. Nelfinavir may provide unique benefits for the prevention or treatment of HIV-associated KS and potentially other human herpesviruses by direct inhibition of replication.

  12. Cancer angiogenesis induced by Kaposi sarcoma-associated herpesvirus is mediated by EZH2.

    PubMed

    He, Meilan; Zhang, Wei; Bakken, Thomas; Schutten, Melissa; Toth, Zsolt; Jung, Jae U; Gill, Parkash; Cannon, Mark; Gao, Shou-Jiang

    2012-07-15

    EZH2 is a component of the epigenetic regulator PRC2 that suppresses gene expression. Elevated expression of EZH2 is common in human cancers and is associated with tumor progression and poor prognosis. In this study, we show that EZH2 elevation is associated with epigenetic modifications of Kaposi sarcoma-associated herpesvirus (KSHV), an oncogenic virus that promotes the development of Kaposi sarcoma and other malignancies that occur in patients with chronic HIV infections. KSHV induction of EZH2 expression was essential for KSHV-induced angiogenesis. High expression of EZH2 was observed in Kaposi sarcoma tumors. In cell culture, latent KSHV infection upregulated the expression of EZH2 in human endothelial cells through the expression of vFLIP and LANA, two KSHV-latent genes that activate the NF-κB pathway. KSHV-mediated upregulation of EZH2 was required for the induction of Ephrin-B2, an essential proangiogenic factor that drives endothelial cell tubule formation. Taken together, our findings indicate that KSHV regulates the host epigenetic modifier EZH2 to promote angiogenesis.

  13. Identification and Characterization of the Orf49 Protein of Kaposi's Sarcoma-Associated Herpesvirus

    PubMed Central

    González, Carlos M.; Wong, Emily L.; Bowser, Brian S.; Hong, Gregory K.; Kenney, Shannon; Damania, Blossom

    2006-01-01

    Kaposi's sarcoma-associated herpesvirus (KSHV) is the etiological agent of Kaposi's sarcoma, primary effusion lymphoma, and multicentric Castleman's disease. Kaposi's sarcoma is the most common neoplasm among human immunodeficiency virus-positive individuals. Like other herpesviruses, KSHV is able to establish a predominantly latent, life-long infection in its host. The KSHV lytic cycle can be triggered by a number of stimuli that induce the expression of the key lytic switch protein, the replication and transcription activator (RTA) encoded by Orf50. The expression of Rta is necessary and sufficient to trigger the full lytic program resulting in the ordered expression of viral proteins, release of viral progeny, and host cell death. We have characterized an unknown open reading frame, Orf49, which lies adjacent and in the opposite orientation to Orf50. Orf49 is expressed during the KSHV lytic cycle and shows early transcription kinetics. We have mapped the 5′ and 3′ ends of the unspliced Orf49 transcript, which encodes a 30-kDa protein that is localized to both the nucleus and the cytoplasm. Interestingly, we found that Orf49 was able to cooperate with Rta to activate several KSHV lytic promoters containing AP-1 sites. The Orf49-encoded protein was also able to induce transcriptional activation through c-Jun but not the ATF1, ATF2, or CREB transcription factor. We found that Orf49 could induce phosphorylation and activation of the transcription factor c-Jun, the Jun N-terminal kinase (JNK), and p38. Our data suggest that Orf49 functions to activate the JNK and p38 pathways during the KSHV lytic cycle. PMID:16501115

  14. MicroRNAs encoded by Kaposi's sarcoma-associated herpesvirus regulate viral life cycle.

    PubMed

    Lu, Chih-Chung; Li, Zhonghan; Chu, Chia-Ying; Feng, Jiaying; Feng, Jun; Sun, Ren; Rana, Tariq M

    2010-10-01

    Kaposi's sarcoma-associated herpesvirus (KSHV) is linked with Kaposi's sarcoma and lymphomas. The pathogenesis of KSHV depends on the balance between two phases of the viral cycle: latency and lytic replication. In this study, we report that KSHV-encoded microRNAs (miRNAs) function as regulators by maintaining viral latency and inhibiting viral lytic replication. MiRNAs are short, noncoding, small RNAs that post-transcriptionally regulate the expression of messenger RNAs. Of the 12 viral miRNAs expressed in latent KSHV-infected cells, we observed that expression of miR-K3 can suppress both viral lytic replication and gene expression. Further experiments indicate that miR-K3 can regulate viral latency by targeting nuclear factor I/B. Nuclear factor I/B can activate the promoter of the viral immediate-early transactivator replication and transcription activator (RTA), and depletion of nuclear factor I/B by short hairpin RNAs had similar effects on the viral life cycle to those of miR-K3. Our results suggest a role for KSHV miRNAs in regulating the viral life cycle.

  15. Kaposi sarcoma-associated herpesvirus promotes tumorigenesis by modulating the Hippo pathway.

    PubMed

    Liu, G; Yu, F-X; Kim, Y C; Meng, Z; Naipauer, J; Looney, D J; Liu, X; Gutkind, J S; Mesri, E A; Guan, K-L

    2015-07-01

    Kaposi sarcoma-associated herpesvirus (KSHV) is an oncogenic virus and the culprit behind the human disease Kaposi sarcoma (KS), an AIDS-defining malignancy. KSHV encodes a viral G-protein-coupled receptor (vGPCR) critical for the initiation and progression of KS. In this study, we identified that YAP/TAZ, two homologous oncoproteins inhibited by the Hippo tumor suppressor pathway, are activated in KSHV-infected cells in vitro, KS-like mouse tumors and clinical human KS specimens. The KSHV-encoded vGPCR acts through Gq/11 and G12/13 to inhibit the Hippo pathway kinases Lats1/2, promoting the activation of YAP/TAZ. Furthermore, depletion of YAP/TAZ blocks vGPCR-induced cell proliferation and tumorigenesis in a xenograft mouse model. The vGPCR-transformed cells are sensitive to pharmacologic inhibition of YAP. Our study establishes a pivotal role of the Hippo pathway in mediating the oncogenic activity of KSHV and development of KS, and also suggests a potential of using YAP inhibitors for KS intervention.

  16. Protein complexes associated with the Kaposi's sarcoma-associated herpesvirus-encoded LANA

    SciTech Connect

    Kaul, Rajeev; Verma, Subhash C.; Robertson, Erle S. . E-mail: erle@mail.med.upenn.edu

    2007-08-01

    Kaposi's sarcoma-associated herpesvirus (KSHV) is the major biological cofactor contributing to development of Kaposi's sarcoma. KSHV establishes a latent infection in human B cells expressing the latency-associated nuclear antigen (LANA), a critical factor in the regulation of viral latency. LANA is known to modulate viral and cellular gene expression. We report here on some initial proteomic studies to identify cellular proteins associated with the amino and carboxy-terminal domains of LANA. The results of these studies show an association of known cellular proteins which support LANA functions and have identified additional LANA-associated proteins. These results provide new evidence for complexes involving LANA with a number of previously unreported functional classes of proteins including DNA polymerase, RNA helicase and cell cycle control proteins. The results also indicate that the amino terminus of LANA can interact with its carboxy-terminal domain. This interaction is potentially important for facilitating associations with other cell cycle regulatory proteins which include CENP-F identified in association with both the amino and carboxy-termini. These novel associations add to the diversity of LANA functions in relation to the maintenance of latency and subsequent transformation of KSHV infected cells.

  17. Subversion of autophagy by Kaposi's sarcoma-associated herpesvirus impairs oncogene-induced senescence.

    PubMed

    Leidal, Andrew M; Cyr, David P; Hill, Richard J; Lee, Patrick W K; McCormick, Craig

    2012-02-16

    Acute oncogenic stress can activate autophagy and facilitate permanent arrest of the cell cycle through a failsafe mechanism known as oncogene-induced senescence (OIS). Kaposi's sarcoma-associated herpesvirus (KSHV) proteins are known to subvert autophagic pathways, but the link to Kaposi's sarcoma pathogenesis is unclear. We find that oncogenic assault caused by latent KSHV infection elicits DNA damage responses (DDRs) characteristic of OIS, yet infected cells display only modest levels of autophagy and fail to senesce. These aberrant responses result from the combined activities of tandemly expressed KSHV v-cyclin and v-FLIP proteins. v-Cyclin deregulates the cell cycle, triggers DDRs, and if left unchecked can promote autophagy and senescence. However, during latency v-FLIP blocks v-cyclin-induced autophagy and senescence in a manner that requires intact v-FLIP ATG3-binding domains. Together, these data reveal a coordinated viral gene expression program that usurps autophagy, blocks senescence, and facilitates the proliferation of KSHV-infected cells. Copyright © 2012 Elsevier Inc. All rights reserved.

  18. Reactive Oxygen Species Hydrogen Peroxide Mediates Kaposi's Sarcoma-Associated Herpesvirus Reactivation from Latency

    PubMed Central

    Ye, Fengchun; Zhou, Fuchun; Bedolla, Roble G.; Jones, Tiffany; Lei, Xiufen; Kang, Tao; Guadalupe, Moraima; Gao, Shou-Jiang

    2011-01-01

    Kaposi's sarcoma-associated herpesvirus (KSHV) establishes a latent infection in the host following an acute infection. Reactivation from latency contributes to the development of KSHV-induced malignancies, which include Kaposi's sarcoma (KS), the most common cancer in untreated AIDS patients, primary effusion lymphoma and multicentric Castleman's disease. However, the physiological cues that trigger KSHV reactivation remain unclear. Here, we show that the reactive oxygen species (ROS) hydrogen peroxide (H2O2) induces KSHV reactivation from latency through both autocrine and paracrine signaling. Furthermore, KSHV spontaneous lytic replication, and KSHV reactivation from latency induced by oxidative stress, hypoxia, and proinflammatory and proangiogenic cytokines are mediated by H2O2. Mechanistically, H2O2 induction of KSHV reactivation depends on the activation of mitogen-activated protein kinase ERK1/2, JNK, and p38 pathways. Significantly, H2O2 scavengers N-acetyl-L-cysteine (NAC), catalase and glutathione inhibit KSHV lytic replication in culture. In a mouse model of KSHV-induced lymphoma, NAC effectively inhibits KSHV lytic replication and significantly prolongs the lifespan of the mice. These results directly relate KSHV reactivation to oxidative stress and inflammation, which are physiological hallmarks of KS patients. The discovery of this novel mechanism of KSHV reactivation indicates that antioxidants and anti-inflammation drugs could be promising preventive and therapeutic agents for effectively targeting KSHV replication and KSHV-related malignancies. PMID:21625536

  19. Reactive oxygen species hydrogen peroxide mediates Kaposi's sarcoma-associated herpesvirus reactivation from latency.

    PubMed

    Ye, Fengchun; Zhou, Fuchun; Bedolla, Roble G; Jones, Tiffany; Lei, Xiufen; Kang, Tao; Guadalupe, Moraima; Gao, Shou-Jiang

    2011-05-01

    Kaposi's sarcoma-associated herpesvirus (KSHV) establishes a latent infection in the host following an acute infection. Reactivation from latency contributes to the development of KSHV-induced malignancies, which include Kaposi's sarcoma (KS), the most common cancer in untreated AIDS patients, primary effusion lymphoma and multicentric Castleman's disease. However, the physiological cues that trigger KSHV reactivation remain unclear. Here, we show that the reactive oxygen species (ROS) hydrogen peroxide (H₂O₂) induces KSHV reactivation from latency through both autocrine and paracrine signaling. Furthermore, KSHV spontaneous lytic replication, and KSHV reactivation from latency induced by oxidative stress, hypoxia, and proinflammatory and proangiogenic cytokines are mediated by H₂O₂. Mechanistically, H₂O₂ induction of KSHV reactivation depends on the activation of mitogen-activated protein kinase ERK1/2, JNK, and p38 pathways. Significantly, H₂O₂ scavengers N-acetyl-L-cysteine (NAC), catalase and glutathione inhibit KSHV lytic replication in culture. In a mouse model of KSHV-induced lymphoma, NAC effectively inhibits KSHV lytic replication and significantly prolongs the lifespan of the mice. These results directly relate KSHV reactivation to oxidative stress and inflammation, which are physiological hallmarks of KS patients. The discovery of this novel mechanism of KSHV reactivation indicates that antioxidants and anti-inflammation drugs could be promising preventive and therapeutic agents for effectively targeting KSHV replication and KSHV-related malignancies.

  20. Transcriptional regulation of the open reading frame 35 encoded by Kaposi's sarcoma-associated herpesvirus.

    PubMed

    Masa, Shiri-Rivka; Lando, Revital; Sarid, Ronit

    2008-02-05

    Kaposi's sarcoma-associated herpesvirus (KSHV) is a member of the Gammaherpesvirinae and is causally associated with Kaposi's sarcoma, primary effusion lymphoma, and multicentric Castleman's disease. The KSHV genome encodes over 85 genes; the function of some is entirely unknown. We have characterized the transcriptional regulation of a conserved and uncharacterized Gammaherpesvirinae open reading frame, orf35, which lies in a cluster of several overlapping genes, orf34 to orf38. We identified the transcription start site and analyzed upstream sequences. We found that expression of the KSHV lytic replication and transcription activator (RTA) strongly increased the orf35 promoter activity through a 46-nucleotide region which includes a conserved AP-1 binding site. Electrophoretic mobility shift assay demonstrated direct binding of cJUN and cFOS to the predicted AP-1 binding site. Finally, using a mutated promoter lacking the AP-1 site and dominant-negative cFOS, we established that the RTA-mediated orf35 transactivation is AP-1-dependent.

  1. Identification and characterization of Kaposi's sarcoma-associated herpesvirus open reading frame 11 promotor activation

    SciTech Connect

    Chen, Lei

    2008-01-01

    Open reading frame 11 (ORF11) of Kaposi's sarcoma-associated herpesvirus belongs to a herpesviral homologous protein family shared by some members of the gamma- herpesvirus subfamily. Little is known about this ORF11 homologous protein family. We have characterized an unknown open reading frame, ORF11, located adjacent and in the opposite orientation to a well-characterized viral IL-6 gene. Northern blot analysis reveals that ORF11 is expressed during the KSHV lytic cycle with delayed-early transcription kinetics. We have determined the 5{prime} and 3{prime} untranslated region of the unspliced ORF11 transcript and identified both the transcription start site and the transcription termination site. Core promoter region, representing ORF11 promoter activity, was mapped to a 159nt fragment 5{prime} most proximal to the transcription start site. A functional TATA box was identified in the core promoter region. Interestingly, we found that ORF11 transcriptional activation is not responsive to Rta, the KSHV lytic switch protein. We also discovered that part of the ORF11 promoter region, the 209nt fragment upstream of the transcription start site, was repressed by phorbol esters. Our data help to understand transcription regulation of ORF11 and to elucidate roles of ORF11 in KSHV pathogenesis and life cycle.

  2. Next-Generation Sequencing in the Understanding of Kaposi's Sarcoma-Associated Herpesvirus (KSHV) Biology.

    PubMed

    Strahan, Roxanne; Uppal, Timsy; Verma, Subhash C

    2016-03-31

    Non-Sanger-based novel nucleic acid sequencing techniques, referred to as Next-Generation Sequencing (NGS), provide a rapid, reliable, high-throughput, and massively parallel sequencing methodology that has improved our understanding of human cancers and cancer-related viruses. NGS has become a quintessential research tool for more effective characterization of complex viral and host genomes through its ever-expanding repertoire, which consists of whole-genome sequencing, whole-transcriptome sequencing, and whole-epigenome sequencing. These new NGS platforms provide a comprehensive and systematic genome-wide analysis of genomic sequences and a full transcriptional profile at a single nucleotide resolution. When combined, these techniques help unlock the function of novel genes and the related pathways that contribute to the overall viral pathogenesis. Ongoing research in the field of virology endeavors to identify the role of various underlying mechanisms that control the regulation of the herpesvirus biphasic lifecycle in order to discover potential therapeutic targets and treatment strategies. In this review, we have complied the most recent findings about the application of NGS in Kaposi's sarcoma-associated herpesvirus (KSHV) biology, including identification of novel genomic features and whole-genome KSHV diversities, global gene regulatory network profiling for intricate transcriptome analyses, and surveying of epigenetic marks (DNA methylation, modified histones, and chromatin remodelers) during de novo, latent, and productive KSHV infections.

  3. Fluorescent Tagging and Cellular Distribution of the Kaposi's Sarcoma-Associated Herpesvirus ORF45 Tegument Protein

    PubMed Central

    Bergson, Shir; Kalt, Inna; Itzhak, Inbal; Brulois, Kevin F.; Jung, Jae U.

    2014-01-01

    ABSTRACT Kaposi's sarcoma-associated herpesvirus (KSHV), also known as human herpesvirus 8 (HHV-8), is a cancer-related human virus, classified as a member of the Gammaherpesvirinae subfamily. We report here the construction of a dual fluorescent-tagged KSHV genome (BAC16-mCherry-ORF45), which constitutively expresses green fluorescent protein (GFP) and contains the tegument multifunctional ORF45 protein as a fusion protein with monomeric Cherry fluorescent protein (mCherry). We confirmed that this virus is properly expressed and correctly replicates and that the mCherry-ORF45 protein is incorporated into the virions. Using this labeled virus, we describe the dynamics of mCherry-ORF45 expression and localization in newly infected cells as well as in latently infected cells undergoing lytic induction and show that mCherry can be used to monitor cells undergoing the lytic viral cycle. This virus is likely to enable future studies monitoring the dynamics of viral trafficking and tegumentation during viral ingress and egress. IMPORTANCE The present study describes the construction and characterization of a new recombinant KSHV genome BAC16 clone which expresses mCherry-tagged ORF45. This virus enables the tracking of cells undergoing lytic infection and can be used to address issues related to the trafficking and maturation pathways of KSHV virions. PMID:25165104

  4. Kaposi's sarcoma-associated herpesvirus in non-AIDS related lymphomas occurring in body cavities.

    PubMed Central

    Cesarman, E.; Nador, R. G.; Aozasa, K.; Delsol, G.; Said, J. W.; Knowles, D. M.

    1996-01-01

    DNA sequences belonging to the recently discovered Kaposi's sarcoma-associated herpesvirus (KSHV), now provisionally designated human herpesvirus 8, have been previously identified in an uncommonly occurring subset of AIDS-related lymphomas, referred to as body-cavity-based lymphomas (BCBLs), which present as lymphomatous effusions. Pyothorax-associated lymphomas (PALS) are non-Hodgkin's lymphomas that arise in the pleural cavity after long-standing pleural inflammation resulting from therapeutic artificial pneumothorax or from tuberculosis pleuritis. Although PALs present as solid tumor masses, they are otherwise similar to BCBLs in that they also are B cell lymphomas, usually exhibit immunoblastic morphology, and contain Epstein-Barr virus. We investigated whether KSHV sequences are present in 2 BCBLs in patients without AIDS and 12 in Japanese and 2 French PALs. The 2 BCBLs were positive for KSHV sequences, whereaas all 14 PALs were KSHV negative. This finding strongly suggests that BCBLs and PALs are distinct clinicopathological entities and further strengthens the association between the presence of KSHV and an effusion phenotype. Based on these findings, we propose replacing the term body-cavity-based lymphoma with the term primary effusion lymphoma, which describes these non-Hodgkin's lymphomas more accurately and avoids confusion with other lymphomas that may occur in the body cavities, such as the PALs. Images Figure 1 Figure 2 PMID:8686762

  5. Modulation of Kaposi's sarcoma-associated herpesvirus interleukin-6 function by hypoxia-upregulated protein 1.

    PubMed

    Giffin, Louise; Yan, Feng; Ben Major, M; Damania, Blossom

    2014-08-01

    Kaposi's sarcoma-associated herpesvirus (KSHV, also called human herpesvirus 8) is linked to the development of Kaposi's sarcoma (KS), primary effusion lymphoma (PEL), and multicentric Castleman's disease (MCD). KSHV expresses several proteins that modulate host cell signaling pathways. One of these proteins is viral interleukin-6 (vIL-6), which is a homolog of human IL-6 (hIL-6). vIL-6 is able to prevent apoptosis and promote proinflammatory signaling, angiogenesis, and cell proliferation. Although it can be secreted, vIL-6 is mainly an intracellular protein that is retained in the endoplasmic reticulum (ER). We performed affinity purification and mass spectrometry to identify novel vIL-6 binding partners and found that a cellular ER chaperone, hypoxia-upregulated protein 1 (HYOU1), interacts with vIL-6. Immunohistochemical staining reveals that both PEL and KS tumor tissues express significant amounts of HYOU1. We also show that HYOU1 increases endogenous vIL-6 protein levels and that HYOU1 facilitates vIL-6-induced JAK/STAT signaling, migration, and survival in endothelial cells. Furthermore, our data suggest that HYOU1 also modulates vIL-6's ability to induce CCL2, a chemokine involved in cell migration. Finally, we investigated the impact of HYOU1 on cellular hIL-6 signaling. Collectively, our data indicate that HYOU1 is important for vIL-6 function and may play a role in the pathogenesis of KSHV-associated cancers. KSHV vIL-6 is detectable in all KSHV-associated malignancies and promotes tumorigenesis and inflammation. We identified a cellular protein, called hypoxia-upregulated protein 1 (HYOU1), that interacts with KSHV vIL-6 and is present in KSHV-infected tumors. Our data suggest that HYOU1 facilitates the vIL-6-induced signaling, migration, and survival of endothelial cells. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

  6. Kaposi's Sarcoma-Associated Herpesvirus Hijacks RNA Polymerase II To Create a Viral Transcriptional Factory.

    PubMed

    Chen, Christopher Phillip; Lyu, Yuanzhi; Chuang, Frank; Nakano, Kazushi; Izumiya, Chie; Jin, Di; Campbell, Mel; Izumiya, Yoshihiro

    2017-06-01

    Locally concentrated nuclear factors ensure efficient binding to DNA templates, facilitating RNA polymerase II recruitment and frequent reutilization of stable preinitiation complexes. We have uncovered a mechanism for effective viral transcription by focal assembly of RNA polymerase II around Kaposi's sarcoma-associated herpesvirus (KSHV) genomes in the host cell nucleus. Using immunofluorescence labeling of latent nuclear antigen (LANA) protein, together with fluorescence in situ RNA hybridization (RNA-FISH) of the intron region of immediate early transcripts, we visualized active transcription of viral genomes in naturally infected cells. At the single-cell level, we found that not all episomes were uniformly transcribed following reactivation stimuli. However, those episomes that were being transcribed would spontaneously aggregate to form transcriptional "factories," which recruited a significant fraction of cellular RNA polymerase II. Focal assembly of "viral transcriptional factories" decreased the pool of cellular RNA polymerase II available for cellular gene transcription, which consequently impaired cellular gene expression globally, with the exception of selected ones. The viral transcriptional factories localized with replicating viral genomic DNAs. The observed colocalization of viral transcriptional factories with replicating viral genomic DNA suggests that KSHV assembles an "all-in-one" factory for both gene transcription and DNA replication. We propose that the assembly of RNA polymerase II around viral episomes in the nucleus may be a previously unexplored aspect of KSHV gene regulation by confiscation of a limited supply of RNA polymerase II in infected cells.IMPORTANCE B cells infected with Kaposi's sarcoma-associated herpesvirus (KSHV) harbor multiple copies of the KSHV genome in the form of episomes. Three-dimensional imaging of viral gene expression in the nucleus allows us to study interactions and changes in the physical distribution of

  7. Kaposi's Sarcoma-Associated Herpesvirus Hijacks RNA Polymerase II To Create a Viral Transcriptional Factory

    PubMed Central

    Chen, Christopher Phillip; Lyu, Yuanzhi; Chuang, Frank; Nakano, Kazushi; Izumiya, Chie; Jin, Di; Campbell, Mel

    2017-01-01

    ABSTRACT Locally concentrated nuclear factors ensure efficient binding to DNA templates, facilitating RNA polymerase II recruitment and frequent reutilization of stable preinitiation complexes. We have uncovered a mechanism for effective viral transcription by focal assembly of RNA polymerase II around Kaposi's sarcoma-associated herpesvirus (KSHV) genomes in the host cell nucleus. Using immunofluorescence labeling of latent nuclear antigen (LANA) protein, together with fluorescence in situ RNA hybridization (RNA-FISH) of the intron region of immediate early transcripts, we visualized active transcription of viral genomes in naturally infected cells. At the single-cell level, we found that not all episomes were uniformly transcribed following reactivation stimuli. However, those episomes that were being transcribed would spontaneously aggregate to form transcriptional “factories,” which recruited a significant fraction of cellular RNA polymerase II. Focal assembly of “viral transcriptional factories” decreased the pool of cellular RNA polymerase II available for cellular gene transcription, which consequently impaired cellular gene expression globally, with the exception of selected ones. The viral transcriptional factories localized with replicating viral genomic DNAs. The observed colocalization of viral transcriptional factories with replicating viral genomic DNA suggests that KSHV assembles an “all-in-one” factory for both gene transcription and DNA replication. We propose that the assembly of RNA polymerase II around viral episomes in the nucleus may be a previously unexplored aspect of KSHV gene regulation by confiscation of a limited supply of RNA polymerase II in infected cells. IMPORTANCE B cells infected with Kaposi's sarcoma-associated herpesvirus (KSHV) harbor multiple copies of the KSHV genome in the form of episomes. Three-dimensional imaging of viral gene expression in the nucleus allows us to study interactions and changes in the

  8. Ugandan Kaposi's sarcoma-associated herpesvirus phylogeny: evidence for cross-ethnic transmission of viral subtypes.

    PubMed

    Kajumbula, Henry; Wallace, Robert G; Zong, Jian-Chao; Hokello, Joseph; Sussman, Noah; Simms, Simon; Rockwell, Robert F; Pozos, Robert; Hayward, Gary S; Boto, William

    2006-01-01

    The aim of this study was to test the relationship between Kaposi's sarcoma-associated herpesvirus (KSHV) phylogeny and host ethnicity at the within-country scale. KSHV genomic DNA samples were isolated from 31 patients across eleven Ugandan ethnic groups. Amino acid sequences of the ORF-K1 gene were used to construct a neighbor-joining phylogenetic tree. A5 and B1 variants predominated with no evidence of distinct ethnic or geographic distribution. A new K1 subtype (F) was identified in a member of the Bantu Gisu tribe and a new subtype B variant (B3) among members of the Bantu Ganda tribe. The phylogeny may yet be structured by host ethnicity if members of Ugandan groups have convoluted biological origins, even as they identify with single tribes. An alternative possibility is that KSHV subtype evolution may have preceded major diversification of sub-Saharan Africans into ethnicities as we know them today, with ethnic groups beginning their histories already hosting multiple subtypes. A third alternative is that horizontal transmission of multiple KSHV subtypes may have broken up vertical lineages of the virus passed down within Ugandan populations.

  9. RNA Sequencing Reveals that Kaposi Sarcoma-Associated Herpesvirus Infection Mimics Hypoxia Gene Expression Signature

    PubMed Central

    Viollet, Coralie; Davis, David A.; Tekeste, Shewit S.; Reczko, Martin; Pezzella, Francesco; Ragoussis, Jiannis

    2017-01-01

    Kaposi sarcoma-associated herpesvirus (KSHV) causes several tumors and hyperproliferative disorders. Hypoxia and hypoxia-inducible factors (HIFs) activate latent and lytic KSHV genes, and several KSHV proteins increase the cellular levels of HIF. Here, we used RNA sequencing, qRT-PCR, Taqman assays, and pathway analysis to explore the miRNA and mRNA response of uninfected and KSHV-infected cells to hypoxia, to compare this with the genetic changes seen in chronic latent KSHV infection, and to explore the degree to which hypoxia and KSHV infection interact in modulating mRNA and miRNA expression. We found that the gene expression signatures for KSHV infection and hypoxia have a 34% overlap. Moreover, there were considerable similarities between the genes up-regulated by hypoxia in uninfected (SLK) and in KSHV-infected (SLKK) cells. hsa-miR-210, a HIF-target known to have pro-angiogenic and anti-apoptotic properties, was significantly up-regulated by both KSHV infection and hypoxia using Taqman assays. Interestingly, expression of KSHV-encoded miRNAs was not affected by hypoxia. These results demonstrate that KSHV harnesses a part of the hypoxic cellular response and that a substantial portion of hypoxia-induced changes in cellular gene expression are induced by KSHV infection. Therefore, targeting hypoxic pathways may be a useful way to develop therapeutic strategies for KSHV-related diseases. PMID:28046107

  10. Humanized-BLT mouse model of Kaposi's sarcoma-associated herpesvirus infection.

    PubMed

    Wang, Lin-Xu; Kang, Guobin; Kumar, Pankaj; Lu, Wuxun; Li, Yue; Zhou, You; Li, Qingsheng; Wood, Charles

    2014-02-25

    Lack of an effective small-animal model to study the Kaposi's sarcoma-associated herpesvirus (KSHV) infection in vivo has hampered studies on the pathogenesis and transmission of KSHV. The objective of our study was to determine whether the humanized BLT (bone marrow, liver, and thymus) mouse (hu-BLT) model generated from NOD/SCID/IL2rγ mice can be a useful model for studying KSHV infection. We have tested KSHV infection of hu-BLT mice via various routes of infection, including oral and intravaginal routes, to mimic natural routes of transmission, with recombinant KSHV over a 1- or 3-mo period. Infection was determined by measuring viral DNA, latent and lytic viral transcripts and antigens in various tissues by PCR, in situ hybridization, and immunohistochemical staining. KSHV DNA, as well as both latent and lytic viral transcripts and proteins, were detected in various tissues, via various routes of infection. Using double-labeled immune-fluorescence confocal microscopy, we found that KSHV can establish infection in human B cells and macrophages. Our results demonstrate that KSHV can establish a robust infection in the hu-BLT mice, via different routes of infection, including the oral mucosa which is the most common natural route of infection. This hu-BLT mouse not only will be a useful model for studying the pathogenesis of KSHV in vivo but can potentially be used to study the routes and spread of viral infection in the infected host.

  11. RNA Sequencing Reveals that Kaposi Sarcoma-Associated Herpesvirus Infection Mimics Hypoxia Gene Expression Signature.

    PubMed

    Viollet, Coralie; Davis, David A; Tekeste, Shewit S; Reczko, Martin; Ziegelbauer, Joseph M; Pezzella, Francesco; Ragoussis, Jiannis; Yarchoan, Robert

    2017-01-01

    Kaposi sarcoma-associated herpesvirus (KSHV) causes several tumors and hyperproliferative disorders. Hypoxia and hypoxia-inducible factors (HIFs) activate latent and lytic KSHV genes, and several KSHV proteins increase the cellular levels of HIF. Here, we used RNA sequencing, qRT-PCR, Taqman assays, and pathway analysis to explore the miRNA and mRNA response of uninfected and KSHV-infected cells to hypoxia, to compare this with the genetic changes seen in chronic latent KSHV infection, and to explore the degree to which hypoxia and KSHV infection interact in modulating mRNA and miRNA expression. We found that the gene expression signatures for KSHV infection and hypoxia have a 34% overlap. Moreover, there were considerable similarities between the genes up-regulated by hypoxia in uninfected (SLK) and in KSHV-infected (SLKK) cells. hsa-miR-210, a HIF-target known to have pro-angiogenic and anti-apoptotic properties, was significantly up-regulated by both KSHV infection and hypoxia using Taqman assays. Interestingly, expression of KSHV-encoded miRNAs was not affected by hypoxia. These results demonstrate that KSHV harnesses a part of the hypoxic cellular response and that a substantial portion of hypoxia-induced changes in cellular gene expression are induced by KSHV infection. Therefore, targeting hypoxic pathways may be a useful way to develop therapeutic strategies for KSHV-related diseases.

  12. Targeted inhibition of calcineurin signaling blocks calcium-dependent reactivation of Kaposi sarcoma-associated herpesvirus.

    PubMed

    Zoeteweij, J P; Moses, A V; Rinderknecht, A S; Davis, D A; Overwijk, W W; Yarchoan, R; Orenstein, J M; Blauvelt, A

    2001-04-15

    Kaposi sarcoma-associated herpesvirus (KSHV) is associated with KS, primary effusion lymphoma (PEL), and multicentric Castleman disease. Reactivation of KSHV in latently infected cells and subsequent plasma viremia occur before the development of KS. Intracellular signaling pathways involved in KSHV reactivation were studied. In latently infected PEL cells (BCBL-1), KSHV reactivation in single cells was determined by quantitative flow cytometry. Viral particle production was determined by electron microscope analyses and detection of minor capsid protein in culture supernatants. Agents that mobilized intracellular calcium (ionomycin, thapsigargin) induced expression of KSHV lytic cycle-associated proteins and led to increased virus production. Calcium-mediated virus reactivation was blocked by specific inhibitors of calcineurin-dependent signal transduction (cyclosporine, FK506). Similarly, calcium-mediated virus reactivation in KSHV-infected dermal microvascular endothelial cells was blocked by cyclosporine. Furthermore, retroviral transduction with plasmid DNA encoding VIVIT, a peptide specifically blocking calcineurin-NFAT interactions, inhibited calcium-dependent KSHV reactivation. By contrast, chemical induction of lytic-phase infection by the phorbol ester 12-O-tetradecanoyl-phorbol-13-acetate was blocked by protein kinase C inhibitors, but not by calcineurin inhibitors. In summary, calcineurin-dependent signal transduction, an important signaling cascade in vivo, induces calcium-dependent KSHV replication, providing a possible target for the design of antiherpesvirus strategies in KSHV-infected patients.

  13. Host and viral proteins in the virion of Kaposi's sarcoma-associated herpesvirus.

    PubMed

    Bechtel, Jill T; Winant, Richard C; Ganem, Don

    2005-04-01

    Infection of cultured cells with Kaposi's sarcoma associated herpesvirus (KSHV) typically establishes a latent infection, in which only a few viral genes are expressed. Recently, it has been reported that a subset of lytic genes are transiently expressed very early after viral entry but that this burst of abortive lytic gene expression is terminated with the supervention of latency (H. H. Krishnan, P. P. Naranatt, M. S. Smith, L. Zeng, C. Bloomer, and B. Chandran, J. Virol. 78:3601-3620, 2004). To identify molecules imported into cells by KSHV that might influence this gene expression program, we have examined the protein composition of the KSHV particle. Immunoblotting of virus particles demonstrated that RTA, the lytic switch protein, and RAP, a viral protein that is a transcriptional and cell cycle modulator, were both incorporated into virus particles. In a second approach, polypeptides isolated from purified virions were identified by mass-spectrometric analysis of their constituent tryptic peptides. With this approach we were able to identify 18 major virion proteins, including structural, regulatory, and signaling proteins of both viral and cellular origin.

  14. CTCF Regulates Kaposi's Sarcoma-Associated Herpesvirus Latency Transcription by Nucleosome Displacement and RNA Polymerase Programming

    PubMed Central

    Cho, Hyosun; Sung, Gi-Ho

    2013-01-01

    CCCTC-binding factor (CTCF) has been implicated in various aspects of viral and host chromatin organization and transcriptional control. We showed previously that CTCF binds to a cluster of three sites in the first intron of the Kaposi's sarcoma-associated herpesvirus (KSHV) multicistronic latency-associated transcript that encodes latency-associated nuclear antigen (LANA), viral cyclin (vCyclin), vFLIP, viral microRNAs, and kaposin. We show here that these CTCF binding sites regulate mRNA production, RNA polymerase II (RNAPII) programming, and nucleosome organization of the KSHV latency transcript control region. We also show that KSHV bacmids lacking these CTCF binding sites have elevated and altered ratios of spliced latency transcripts. CTCF binding site mutations altered RNAPII and RNAPII-accessory factor interactions with the latency control region. CTCF binding sites were required for the in vitro recruitment of RNAPII to the latency control region, suggesting that direct interactions between CTCF and RNAPII contribute to transcription regulation. Histone modifications in the latency control region were also altered by mutations in the CTCF binding sites. Finally, we show that CTCF binding alters the regular phasing of nucleosomes in the latency gene transcript and intron, suggesting that nucleosome positioning can be an underlying biochemical mechanism of CTCF function. We propose that RNAPII interactions and nucleosome displacement serve as a biochemical basis for programming RNAPII in the KSHV transcriptional control region. PMID:23192870

  15. Control of Kaposi's Sarcoma-Associated Herpesvirus Reactivation Induced by Multiple Signals

    PubMed Central

    Feng, Jiaying; Li, Xudong; Liao, Chia Wei; Ho, Chih-Ming; Shamma, Jeff S.; Sun, Ren

    2011-01-01

    The ability to control cellular functions can bring about many developments in basic biological research and its applications. The presence of multiple signals, internal as well as externally imposed, introduces several challenges for controlling cellular functions. Additionally the lack of clear understanding of the cellular signaling network limits our ability to infer the responses to a number of signals. This work investigates the control of Kaposi's sarcoma-associated herpesvirus reactivation upon treatment with a combination of multiple signals. We utilize mathematical model-based as well as experiment-based approaches to achieve the desired goals of maximizing virus reactivation. The results show that appropriately selected control signals can induce virus lytic gene expression about ten folds higher than a single drug; these results were validated by comparing the results of the two approaches, and experimentally using multiple assays. Additionally, we have quantitatively analyzed potential interactions between the used combinations of drugs. Some of these interactions were consistent with existing literature, and new interactions emerged and warrant further studies. The work presents a general method that can be used to quantitatively and systematically study multi-signal induced responses. It enables optimization of combinations to achieve desired responses. It also allows identifying critical nodes mediating the multi-signal induced responses. The concept and the approach used in this work will be directly applicable to other diseases such as AIDS and cancer. PMID:21904595

  16. Epidemiology of Kaposi's sarcoma-associated herpesvirus in Asia: Challenges and opportunities.

    PubMed

    Zhang, Tiejun; Wang, Linding

    2017-04-01

    Kaposi's sarcoma-associated herpes virus (KSHV) also referred to as human herpesvirus-8 (HHV-8), is a gamma herpes virus and recently discovered human virus. Since its discovery, a myriad of studies has been conducted to explore its pathogenesis mechanisms. However, despite our consistently increasing understanding of KSHV biology and its clinical manifestations, only little progress has been made in understanding of its epidemiology characteristics which in turn hampered the management of KSHV-associated diseases and public health. Asia, the largest continent with a diversity of populations, has been thought to be with relative lower KSHV prevalence and diseases burden. The epidemiology of KSHV in this area is obscure either. The present review summarizes the current knowledge pertaining to the epidemiology of KSHV across Asian countries. Studies available in the literature have shown a substantial variation in this region indicating the virus is not ubiquitous in Asia countries as is the case with other human herpes viruses. Also, the MSM has been reconfirmed to be at the highest risk of KSHV infection in Asia highlighting the need for an increased focus on this previously marginalized population. Because of the paucity of data available, the epidemiologic characteristics of KSHV are difficult to determine in Asian countries. Future systematic collection of data to inform KSHV prevention strategies in Asia is urgently needed. J. Med. Virol. 89:563-570, 2017. © 2016 Wiley Periodicals, Inc.

  17. Role of heme oxygenase-1 in the pathogenesis and tumorigenicity of Kaposi's sarcoma-associated herpesvirus.

    PubMed

    Dai, Lu; Qiao, Jing; Nguyen, David; Struckhoff, Amanda P; Doyle, Lisa; Bonstaff, Karlie; Del Valle, Luis; Parsons, Chris; Toole, Bryan P; Renne, Rolf; Qin, Zhiqiang

    2016-03-01

    Kaposi's Sarcoma-associated Herpesvirus (KSHV) is the etiologic agent of several malignancies, including Kaposi's Sarcoma (KS), which preferentially arise in immunocompromised patients such as HIV+ subpopulation and lack effective therapeutic options. Heme oxygenase-1 (HO-1) has been reported as an important regulator of endothelial cell cycle control, proliferation and angiogenesis. HO-1 has also been found to be highly expressed in KSHV-infected endothelial cells and oral AIDS-KS lesions. We previously demonstrate that the multifunctional glycoprotein CD147 is required for KSHV/LANA-induced endothelial cell invasiveness. During the identification of CD147 controlled downstream genes by microarray analysis, we found that the expression of HO-1 is significantly elevated in both CD147-overexpressing and KSHV-infected HUVEC cells when compared to control cells. In the current study, we further identify the regulation of HO-1 expression and mediated cellular functions by both CD147 and KSHV-encoded LANA proteins. Targeting HO-1 by either RNAi or the chemical inhibitor, SnPP, effectively induces cell death of KSHV-infected endothelial cells (the major cellular components of KS) through DNA damage and necrosis process. By using a KS-like nude mouse model, we found that SnPP treatment significantly suppressed KSHV-induced tumorigenesis in vivo. Taken together, our data demonstrate the important role of HO-1 in the pathogenesis and tumorigenesis of KSHV-infected endothelial cells, the underlying regulatory mechanisms for HO-1 expression and targeting HO-1 may represent a promising therapeutic strategy against KSHV-related malignancies.

  18. Peripheral Blood Endothelial Progenitors as Potential Reservoirs of Kaposi's Sarcoma-Associated Herpesvirus

    PubMed Central

    Della Bella, Silvia; Brambilla, Lucia; Bellinvia, Monica; Bergamo, Elisa; Clerici, Mario; Villa, Maria L.

    2008-01-01

    Background The cellular reservoirs of Kaposi's sarcoma-associated herpesvirus (KSHV) and the exact nature of the putative KSHV-infected circulating precursor of spindle cells of Kaposi's sarcoma (KS) still remain poorly defined. Because KS spindle cells are thought to be of endothelial origin, and because mature endothelial cells do not sustain persistent KSHV-infection, our attention was focalized on circulating hematopoietic precursors able to differentiate into endothelial lineage. Methods and Findings Late endothelial progenitor cells (late-EPCs) were cultured from the peripheral blood mononuclear cells of 16 patients with classic KS. The presence and load of KSHV genomes were analyzed by real-time polymerase chain reaction in DNA extracted from cells and supernatants of late-EPC cultures obtained from 7 patients. Endothelial colonies cultured from the peripheral blood of KS patients were found to satisfy all requisites to be defined late-EPCs: they appeared from the CD14-negative fraction of adherent cells after 11–26 days of culture, could be serially expanded in vitro, expressed high levels of endothelial antigens but lacked leukocyte markers. Late-EPC cultures were found to harbor KSHV-DNA at variable levels and to retain the virus after multiple passages in cells as well as in supernatants, suggesting that a quote of KSHV lytic infection may spontaneously occur. Lytic phase induction or hypoxia could amplify virus release in supernatants. Conclusion Our results suggest that circulating endothelial progenitors from KS patients are KSHV-infected and support viral productive replication and may therefore represent potential virus reservoirs and putative precursors of KS spindle cells. PMID:18231605

  19. Latency-associated nuclear antigen of Kaposi sarcoma-associated herpesvirus promotes angiogenesis through targeting notch signaling effector Hey1.

    PubMed

    Wang, Xing; He, Zhiheng; Xia, Tian; Li, Xiaofan; Liang, Deguang; Lin, Xianzhi; Wen, Hao; Lan, Ke

    2014-04-01

    Notch signaling has been implicated in the pathogenesis of Kaposi sarcoma. Kaposi sarcoma is an angioproliferative neoplasm that originates from Kaposi sarcoma-associated herpesvirus (KSHV) infection. Previously, we showed that the KSHV LANA protein can stabilize intracellular Notch in KSHV-infected tumor cells and promote cell proliferation. However, whether Notch signaling functions in pathologic angiogenesis of Kaposi sarcoma remains largely unknown. Hey1, an essential downstream effector of the Notch signaling pathway, has been demonstrated to play a fundamental role in vascular development. In the present study, we performed whole transcriptome, paired-end sequencing on three patient-matched clinical Kaposi sarcoma specimens and their corresponding adjacent stroma samples, with an average depth of 42 million reads per sample. Dll4, Hey1, and HeyL displayed significant upregulation in Kaposi sarcoma. Further verification based on immunohistochemistry analysis demonstrated that Hey1 was indeed highly expressed in Kaposi sarcoma lesions. Using the Matrigel plug assay, we showed that downregulation of Hey1 and γ-secretase inhibitor treatment caused dramatic reduction in the formation of new blood vessels in mice. Interestingly, LANA was responsible for the elevated level of Hey1 through inhibition of its degradation. Importantly, Hey1 stabilized by LANA promoted the neoplastic vasculature. Taken together, our data suggest that hijacking of the proangiogenic property of Hey1 by LANA is an important strategy utilized by KSHV to achieve pathologic angiogenesis and that Hey1 is a potential therapeutic target in Kaposi sarcoma.

  20. Intracellular-activated Notch1 can reactivate Kaposi's sarcoma-associated herpesvirus from latency

    SciTech Connect

    Lan, Ke; Murakami, Masanao; Choudhuri, Tathagata; Kuppers, Daniel A.; Robertson, Erle S. . E-mail: erle@mail.med.upenn.edu

    2006-08-01

    Kaposi's sarcoma-associated herpesvirus (KSHV) establishes a predominantly latent infection in the infected host. Importantly, during latency, only a small number of viral encoded genes are expressed. This viral gene expression pattern contributes to the establishment of long-term infection as well as the ability of the virus to evade the immune system. Previous studies have been shown that the replication and transcription activator (RTA) encoded by ORF50 activates it downstream genes and initiates viral lytic reactivation through functional interaction with RBP-J{kappa}, the major downstream effector of the Notch signaling pathway. This indicates that RTA can usurp the conserved Notch signaling pathway and mimic the activities of intracellular Notch1 to modulate gene expression. In this report, we show that the activated intracellular domain of Notch1 (ICN) is aberrantly accumulated in KSHV latently infected pleural effusion lymphoma (PEL) cells. ICN activated the RTA promoter in a dose-dependent manner, and forced expression of ICN in latently infected KSHV-positive cells initiated full blown lytic replication with the production of infectious viral progeny. However, latency-associated nuclear antigen (LANA) which is predominantly expressed during latency can specifically down-modulate ICN-mediated transactivation of RTA and so control KSHV for lytic reactivation. These results demonstrate that LANA can inhibit viral lytic replication by antagonizing ICN function and suggest that LANA is a critical component of the regulatory control mechanism for switching between viral latent and lytic replication by directly interacting with effectors of the conserved cellular Notch1 pathway.

  1. Viral Bcl-2 Encoded by the Kaposi's Sarcoma-Associated Herpesvirus Is Vital for Virus Reactivation

    PubMed Central

    Gelgor, Anastasia; Kalt, Inna; Bergson, Shir; Brulois, Kevin F.; Jung, Jae U.

    2015-01-01

    ABSTRACT The Kaposi's sarcoma-associated herpesvirus (KSHV) open reading frame 16 (orf16) encodes a viral Bcl-2 (vBcl-2) protein which shares sequence and functional homology with the Bcl-2 family. Like its cellular homologs, vBcl-2 protects various cell types from apoptosis and can also negatively regulate autophagy. vBcl-2 is transcribed during lytic infection; however, its exact function has not been determined to date. By using bacterial artificial chromosome 16 (BAC16) clone carrying the full-length KSHV genome, we have generated recombinant KSHV mutants that fail to express vBcl-2 or express mCherry-tagged vBcl-2. We show that the vBcl-2 protein is expressed at relatively low levels during lytic induction and that a lack of vBcl-2 largely reduces the efficiency of KSHV reactivation in terms of lytic gene expression, viral DNA replication, and production of infectious particles. In contrast, the establishment of latency was not affected by the absence of vBcl-2. Our findings suggest an important role for vBcl-2 during initial phases of lytic reactivation and/or during subsequent viral propagation. Given the known functions of vBcl-2 in regulating apoptosis and autophagy, which involve its direct interaction with cellular proteins and thus require high levels of protein expression, it appears that vBcl-2 may have additional regulatory functions that do not depend on high levels of protein expression. IMPORTANCE The present study shows for the first time the expression of endogenous vBcl-2 protein in KSHV-infected cell lines and demonstrates the importance of vBcl-2 during the initial phases of lytic reactivation and/or during its subsequent propagation. It is suggested that vBcl-2 has additional regulatory functions beyond apoptosis and autophagy repression that do not depend on high levels of protein expression. PMID:25740992

  2. Seroprevalence of antibodies against Kaposi's sarcoma-associated herpesvirus among HIV-negative people in China.

    PubMed

    Zhang, Tiejun; Liu, Zhenqiu; Wang, Jun; Minhas, Veenu; Wood, Charles; Clifford, Gary M; He, Na; Franceschi, Silvia

    2017-01-01

    Little information on the prevalence of Kaposi's sarcoma associated herpesvirus (KSHV) among HIV-negative individuals is available from Asia. In the present study, we report findings from a new survey of KSHV in 983 HIV-negative male migrants from Shanghai and their combination with previous similar surveys of 600 female migrants, 600 female sex-workers (FSW), 1336 sexually transmitted infection (STI) clinic male patients, 439 intravenous drug-users (IVDU), and 226 men having sex with men (MSM) from China. KSHV-specific antibodies against latent and lytic antigens were assessed using Sf9 and BC3 monoclonal immunofluorescence assay. Age-adjusted prevalence ratios (PR) and 95% confidence interval (95% CI) for KSHV-positivity were estimated using Poisson regression. In total, 4184 HIV-negative participants were included. KSHV prevalence ranged from 9.8% (95% CI: 7.9%-11.7%) in male migrants to 32.3% (95% CI: 24.1%-34.1%) in MSM. IVDU show intermediate level (17.5%, 95%CI: 14.1%-21.4%). KSHV was associated with syphilis (PR = 2.03, 95% CI: 1.38-2.98) in MSM but not in other groups. An association with human herpes virus 2 was also found among MSM (PR = 1. 83, 95%: 1.22-2.75) but not in migrant workers or FSW. KSHV prevalence in HIV-negative heterosexuals, FSW, and STI male patients from China is approximately 10%, but 2- and 3-fold higher in IVDU and MSM, respectively. Associations of KSHV with STIs among MSM only suggest that sexual transmission of the virus is important in MSM but not in heterosexuals.

  3. Subcellular fractionation method to study endosomal trafficking of Kaposi's sarcoma-associated herpesvirus.

    PubMed

    Walker, Lia R; Hussein, Hosni A M; Akula, Shaw M

    2016-01-01

    Virus entry involves multiple steps and is a highly orchestrated process on which successful infection collectively depends. Entry processes are commonly analyzed by monitoring internalized virus particles via Western blotting, polymerase chain reaction, and imaging techniques that allow scientist to track the intracellular location of the pathogen. Such studies have provided abundant direct evidence on how viruses interact with receptor molecules on the cell surface, induce cell signaling at the point of initial contact with the cell to facilitate internalization, and exploit existing endocytic mechanisms of the cell for their ultimate infectious agenda. However, there is dearth of knowledge in regards to trafficking of a virus via endosomes. Herein, we describe an optimized laboratory procedure to isolate individual organelles during different stages of endocytosis by performing subcellular fractionation. This methodology is established using Kaposi's sarcoma-associated herpesvirus (KSHV) infection of human foreskin fibroblast (HFF) cells as a model. With KSHV and other herpesviruses alike, envelope glycoproteins have been widely reported to physically engage target cell surface receptors, such as integrins, in interactions leading to entry and subsequent infection. Subcellular fractionation was used to isolate early and late endosomes (EEs and LEs) by performing a series of centrifugations steps. Specifically, a centrifugation step post-homogenization was utilized to obtain the post-nuclear supernatant containing intact intracellular organelles in suspension. Successive fractionation via sucrose density gradient centrifugation was performed to isolate specific organelles including EEs and LEs. Intracellular KSHV trafficking was directly traced in the isolated endosomal fractions. Additionally, the subcellular fractionation approach demonstrates a key role for integrins in the endosomal trafficking of KSHV. The results obtained from fractionation studies

  4. CD147 and downstream ADAMTSs promote the tumorigenicity of Kaposi's sarcoma-associated herpesvirus infected endothelial cells.

    PubMed

    Dai, Lu; Trillo-Tinoco, Jimena; Chen, Yihan; Bonstaff, Karlie; Del Valle, Luis; Parsons, Chris; Ochoa, Augusto C; Zabaleta, Jovanny; Toole, Bryan P; Qin, Zhiqiang

    2016-01-26

    Kaposi's sarcoma-associated herpesvirus (KSHV) is the etiologic agent of several human cancers, including Kaposi's sarcoma (KS), which preferentially arise in immunocompromised patients and lack effective therapeutic options. We have previously shown that KSHV or viral protein LANA up-regulates the glycoprotein CD147, thereby inducing primary endothelial cell invasiveness. In the current study, we identify the global network controlled by CD147 in KSHV-infected endothelial cells using Illumina microarray analysis. Among downstream genes, two specific metalloproteases, ADAMTS1 and 9, are strongly expressed in AIDS-KS tissues and contribute to KSHV-infected endothelial cell invasiveness through up-regulation of IL-6 and VEGF. By using a KS-like nude mouse model, we found that targeting CD147 and downstream ADAMTSs significantly suppressed KSHV-induced tumorigenesis in vivo. Taken together, targeting CD147 and associated proteins may represent a promising therapeutic strategy against these KSHV-related malignancies.

  5. The Crystal Structure of PF-8, the DNA Polymerase Accessory Subunit from Kaposi's Sarcoma-Associated Herpesvirus

    SciTech Connect

    Baltz, Jennifer L.; Filman, David J.; Ciustea, Mihai; Silverman, Janice Elaine Y.; Lautenschlager, Catherine L.; Coen, Donald M.; Ricciardi, Robert P.; Hogle, James M.

    2009-12-01

    Kaposi's sarcoma-associated herpesvirus is an emerging pathogen whose mechanism of replication is poorly understood. PF-8, the presumed processivity factor of Kaposi's sarcoma-associated herpesvirus DNA polymerase, acts in combination with the catalytic subunit, Pol-8, to synthesize viral DNA. We have solved the crystal structure of residues 1 to 304 of PF-8 at a resolution of 2.8 {angstrom}. This structure reveals that each monomer of PF-8 shares a fold common to processivity factors. Like human cytomegalovirus UL44, PF-8 forms a head-to-head dimer in the form of a C clamp, with its concave face containing a number of basic residues that are predicted to be important for DNA binding. However, there are several differences with related proteins, especially in loops that extend from each monomer into the center of the C clamp and in the loops that connect the two subdomains of each protein, which may be important for determining PF-8's mode of binding to DNA and to Pol-8. Using the crystal structures of PF-8, the herpes simplex virus catalytic subunit, and RB69 bacteriophage DNA polymerase in complex with DNA and initial experiments testing the effects of inhibition of PF-8-stimulated DNA synthesis by peptides derived from Pol-8, we suggest a model for how PF-8 might form a ternary complex with Pol-8 and DNA. The structure and the model suggest interesting similarities and differences in how PF-8 functions relative to structurally similar proteins.

  6. Broad target cell selectivity of Kaposi's sarcoma-associated herpesvirus glycoprotein-mediated cell fusion and virion entry

    SciTech Connect

    Kaleeba, Johnan A.R.; Berger, Edward A. . E-mail: edward_berger@nih.gov

    2006-10-10

    The molecular mechanism of Kaposi's sarcoma-associated herpesvirus (KSHV, human herpesvirus 8) entry is poorly understood. We tested a broad variety of cell types of diverse species and tissue origin for their ability to function as targets in a quantitative reporter gene assay for KSHV-glycoprotein-mediated cell fusion. Several human, non-human primate, and rabbit cell lines were efficient targets, whereas rodent and all human lymphoblastoid cell lines were weak targets. Parallel findings were obtained with a virion entry assay using a recombinant KSHV encoding a reporter gene. No correlation was observed between target cell activity and surface expression of {alpha}3{beta}1 integrin, a proposed KSHV receptor. We hypothesize that target cell permissiveness in both the cell fusion and virion entry assays reflects the presence of a putative KSHV fusion-entry receptor.

  7. The contribution of systems biology and reverse genetics to the understanding of Kaposi's sarcoma-associated herpesvirus pathogenesis in endothelial cells.

    PubMed

    Stürzl, Michael; Konrad, Andreas; Alkharsah, Khaled R; Jochmann, Ramona; Thurau, Mathias; Marquardt, Gaby; Schulz, Thomas F

    2009-12-01

    Kaposi's sarcoma-associated herpesvirus (KSHV)/human herpesvirus-8 is the causative agent of the endothelial cell-derived tumour Kaposi's sarcoma. Herpesviruses possess large complex genomes which provide many options to regulate cellular physiology during the viral life cycle and in the course of tumourigenicity. Novel techniques of systems biology and reverse genetics are increasingly applied to dissect the complex interaction of KSHV with endothelial cells. This review will outline novel results and pitfalls of these technologies in the elucidation of KSHV pathogenicity.

  8. The Kaposi's-sarcoma-associated herpesvirus orf35 gene product is required for efficient lytic virus reactivation.

    PubMed

    Bergson, Shir; Itzhak, Inbal; Wasserman, Talya; Gelgor, Anastasia; Kalt, Inna; Sarid, Ronit

    2016-12-01

    Kaposi's sarcoma-associated herpesvirus (KSHV) is implicated in the etiology of several human malignancies. KSHV open reading frame (orf) 35 encodes a conserved gammaherpesvirus protein with an, as yet, unknown function. Employing the bacterial artificial chromosome (BAC) system, we generated a recombinant viral clone that fails to express ORF35 (BAC16-ORF35-stop) but preserves intact adjacent and overlapping reading frames. Using this construct, we studied the role of this previously uncharacterized gene product during lytic reactivation of KSHV. Upon lytic reactivation, the ORF35-stop recombinant virus displayed significantly reduced lytic viral gene expression, viral DNA replication, and progeny virus production as compared to control wild-type virus. Exogenous expression of ORF35-Flag reversed the effects of ORF35 deficiency. These results demonstrate that ORF35 is important for efficient lytic virus reactivation.

  9. Nuclear Localization and Cleavage of STAT6 Is Induced by Kaposi's Sarcoma-Associated Herpesvirus for Viral Latency.

    PubMed

    Wang, Chong; Zhu, Caixia; Wei, Fang; Gao, Shujun; Zhang, Liming; Li, Yuhong; Feng, Yanling; Tong, Yin; Xu, Jianqing; Wang, Bin; Yuan, Zhenghong; Robertson, Erle S; Cai, Qiliang

    2017-01-01

    Emerging evidence implies that STAT6 plays an important role in both the adaptive and innate immune responses to virus infection. Kaposi's sarcoma-associated herpesvirus (KSHV) is an oncogenic γ-herpesvirus agent associated with several human malignancies, including Kaposi's sarcoma (KS) and primary effusion lymphomas (PELs). Previously, we demonstrated that KSHV blocks IL-4-induced STAT6 phosphorylation and retains a basal IL-13/STAT6 constitutive activation for cell survival and proliferation. However, the mechanism by which KSHV regulates STAT6 remains largely unknown. Here, we found that KSHV-encoded LANA interacts with STAT6 and promotes nuclear localization of STAT6 independent of the tyrosine 641-phosphorylation state. Moreover, nuclear localization of STAT6 is also dramatically increased in KS tissue. The latent antigen LANA induces serine protease-mediated cleavage of STAT6 in the nucleus, where the cleaved STAT6 lacking transactivation domain functions as a dominant-negative regulator to repress transcription of Replication and Transcription Activator (RTA) and in turn shut off viral lytic replication. Blockade of STAT6 by small interference RNA dramatically enhances expression of RTA, and in turn reduces KSHV-infected endothelial cell growth and colony formation. Taken together, these results suggest that nuclear localization and cleavage of STAT6 is important for modulating the viral latency and pathogenesis of KSHV.

  10. Regulation and autoregulation of the promoter for the latency-associated nuclear antigen of Kaposi's sarcoma-associated herpesvirus.

    PubMed

    Jeong, Joseph H; Orvis, Joshua; Kim, Jong Wook; McMurtrey, Curtis P; Renne, Rolf; Dittmer, Dirk P

    2004-04-16

    Kaposi's sarcoma-associated herpesvirus (KSHV) or human herpesvirus 8 has been established as the etiological agent of Kaposi's sarcoma and certain AIDS-associated lymphomas. KSHV establishes latent infection in these tumors, invariably expressing high levels of the viral latency-associated nuclear antigen (LANA) protein. LANA is necessary and sufficient to maintain the KSHV episome. It also modulates viral and cellular transcription and has been implicated directly in oncogenesis because of its ability to bind to the p53 and pRb tumor suppressor proteins. Previously, we identified the LANA promoter (LANAp) and showed that it was positively regulated by LANA itself. Here, we present a detailed mutational analysis and define cis-acting elements and trans-acting factors for the core LANAp. We found that a downstream promoter element, TATA box, and GC box/Sp1 site at -29 are all individually required for activity. This architecture places LANAp into the small and unusual group of eukaryotic promoters that contain both the downstream promoter element and TATA element but lack a defined initiation site. Furthermore, we demonstrate that LANA regulates its own promoter via its C-terminal domain and does bind to a defined site within the core promoter.

  11. Fumagillin, a potent angiogenesis inhibitor, induces Kaposi sarcoma-associated herpesvirus replication in primary effusion lymphoma cells.

    PubMed

    Kanno, Takayuki; Uehara, Taeko; Osawa, Madori; Fukumoto, Hitomi; Mine, Sohtaro; Ueda, Keiji; Hasegawa, Hideki; Katano, Harutaka

    2015-08-07

    Kaposi sarcoma and primary effusion lymphoma cells are infected with Kaposi sarcoma-associated herpesvirus (KSHV), predominantly in the latent form, and KSHV replication is observed rarely. Angiogenesis plays a crucial role in the pathogenesis of both Kaposi sarcoma and primary effusion lymphoma. In this study, we found that fumagillin, a potent angiogenesis inhibitor, induced replication of KSHV in primary effusion lymphoma cell lines. The transcript and protein product of replication transcriptional activator (RTA) were induced by 1-10 μM fumagillin at 24 and 48 h, respectively. Western blot analysis demonstrated that 10 μM fumagillin induced not only RTA expression but also other KSHV-encoded lytic proteins. A real-time PCR array detecting KSHV gene expression demonstrated that the expression profiles of KSHV induced by fumagillin were similar to those induced by 12-O-tetradecanoylphorbol-13-acetate (TPA), but the amounts of each transcript were lower than those induced by TPA. Finally, real-time PCR demonstrated an increase in that viral DNA copy number per cell in fumagillin-stimulated primary effusion lymphoma cell lines, indicating replication of KSHV. In addition to TPA, 10 μM fumagillin resulted in growth inhibition of primary effusion lymphoma cell lines. These observations suggest that an angiogenesis inhibitor is an agent with potent effects on cell growth and KSHV reactivation in primary effusion lymphoma cells. Copyright © 2015 Elsevier Inc. All rights reserved.

  12. Cannabidiol inhibits growth and induces programmed cell death in kaposi sarcoma-associated herpesvirus-infected endothelium.

    PubMed

    Maor, Yehoshua; Yu, Jinlong; Kuzontkoski, Paula M; Dezube, Bruce J; Zhang, Xuefeng; Groopman, Jerome E

    2012-07-01

    Kaposi sarcoma is the most common neoplasm caused by Kaposi sarcoma-associated herpesvirus (KSHV). It is prevalent among the elderly in the Mediterranean, inhabitants of sub-Saharan Africa, and immunocompromised individuals such as organ transplant recipients and AIDS patients. Current treatments for Kaposi sarcoma can inhibit tumor growth but are not able to eliminate KSHV from the host. When the host's immune system weakens, KSHV begins to replicate again, and active tumor growth ensues. New therapeutic approaches are needed. Cannabidiol (CBD), a plant-derived cannabinoid, exhibits promising antitumor effects without inducing psychoactive side effects. CBD is emerging as a novel therapeutic for various disorders, including cancer. In this study, we investigated the effects of CBD both on the infection of endothelial cells (ECs) by KSHV and on the growth and apoptosis of KSHV-infected ECs, an in vitro model for the transformation of normal endothelium to Kaposi sarcoma. While CBD did not affect the efficiency with which KSHV infected ECs, it reduced proliferation and induced apoptosis in those infected by the virus. CBD inhibited the expression of KSHV viral G protein-coupled receptor (vGPCR), its agonist, the chemokine growth-regulated protein α (GRO-α), vascular endothelial growth factor receptor 3 (VEGFR-3), and the VEGFR-3 ligand, vascular endothelial growth factor C (VEGF-C). This suggests a potential mechanism by which CBD exerts its effects on KSHV-infected endothelium and supports the further examination of CBD as a novel targeted agent for the treatment of Kaposi sarcoma.

  13. Increased prevalence of Kaposi΄s sarcoma-associated herpesvirus in the Kaposi΄s sarcoma-endemic area of western Kenya in 1981-2000.

    PubMed

    Senba, M; Buziba, N; Mori, N; Morimoto, K; Nakamura, T

    2011-01-01

    Kaposi΄s sarcoma (KS) had been endemic in Africa before the appearance of human immunodeficiency viruses (HIV) in 1985. Incidence of African KS has increased over the time and the risk of contracting KS become greater in HIV-positive as opposed to HIV-negative individuals. KS specimens were collected in 1981-2000 from 228 surgical cases originating from a KS-endemic area of Western Kenya and examined for Kaposi΄s sarcoma-associated herpesvirus (KSHV) by an immunoperoxidase assay. The results showed that the specimens from 1981-1985 (before the HIV epidemic) were KSHV-positive in 10.3% in contrast to the KSHV positivity of 50.1-63.5% in 1986-2000. The linear increase of KSHV positivity in 1981-2000 was statistically significant. The most plausible explanation for the increased prevalence of KSHV in KS cases is that the endemic KS has changed to the epidemic one.

  14. The exonuclease and host shutoff functions of the SOX protein of Kaposi's sarcoma-associated herpesvirus are genetically separable.

    PubMed

    Glaunsinger, Britt; Chavez, Leonard; Ganem, Don

    2005-06-01

    The Kaposi's sarcoma-associated herpesvirus (KSHV) SOX protein, encoded by ORF37, promotes shutoff of host cell gene expression during lytic viral replication by dramatically impairing mRNA accumulation. SOX is the KSHV homolog of the alkaline exonuclease of other herpesviruses, which has been shown to function as a DNase involved in processing and packaging the viral genome. Although the exonuclease activity of these proteins is widely conserved across all herpesviruses, the host shutoff activity observed for KSHV SOX is not. We show here that SOX expression sharply reduces the half-life of target mRNAs. Extensive mutational analysis reveals that the DNase and host shutoff activities of SOX are genetically separable. Lesions affecting the DNase activity cluster in conserved regions of the protein, but residues critical for mRNA degradation are not conserved across the viral family. Additionally, we present evidence suggesting that the two different functions of SOX occur within distinct cellular compartments-DNase activity in the nucleus and host shutoff activity in the cytoplasm.

  15. Discovery of a Coregulatory Interaction between Kaposi's Sarcoma-Associated Herpesvirus ORF45 and the Viral Protein Kinase ORF36

    PubMed Central

    Avey, Denis; Tepper, Sarah; Pifer, Benjamin; Bahga, Amritpal; Williams, Hunter; Gillen, Joseph; Li, Wenwei; Ogden, Sarah

    2016-01-01

    ABSTRACT Kaposi's sarcoma-associated herpesvirus (KSHV) is the causative agent of three human malignancies. KSHV ORF36 encodes a serine/threonine viral protein kinase, which is conserved throughout all herpesviruses. Although several studies have identified the viral and cellular substrates of conserved herpesvirus protein kinases (CHPKs), the precise functions of KSHV ORF36 during lytic replication remain elusive. Here, we report that ORF36 interacts with another lytic protein, ORF45, in a manner dependent on ORF36 kinase activity. We mapped the regions of ORF36 and ORF45 involved in the binding. Their association appears to be mediated by electrostatic interactions, since deletion of either the highly basic N terminus of ORF36 or an acidic patch of ORF45 abolished the binding. In addition, the dephosphorylation of ORF45 protein dramatically reduced its association with ORF36. Importantly, ORF45 enhances both the stability and kinase activity of ORF36. Consistent with previous studies of CHPK homologs, we detected ORF36 protein in extracellular virions. To investigate the roles of ORF36 in the context of KSHV lytic replication, we used bacterial artificial chromosome mutagenesis to engineer both ORF36-null and kinase-dead mutants. We found that ORF36-null/mutant virions are moderately defective in viral particle production and are further deficient in primary infection. In summary, our results uncover a functionally important interaction between ORF36 and ORF45 and indicate a significant role of ORF36 in the production of infectious progeny virions. IMPORTANCE Kaposi's sarcoma-associated herpesvirus (KSHV) is a human tumor virus with a significant public health burden. KSHV ORF36 encodes a serine/threonine viral protein kinase, whose functions throughout the viral life cycle have not been elucidated. Here, we report that ORF36 interacts with another KSHV protein, ORF45. We mapped the regions of ORF36 and ORF45 involved in their association and further

  16. Discovery of a Coregulatory Interaction between Kaposi's Sarcoma-Associated Herpesvirus ORF45 and the Viral Protein Kinase ORF36.

    PubMed

    Avey, Denis; Tepper, Sarah; Pifer, Benjamin; Bahga, Amritpal; Williams, Hunter; Gillen, Joseph; Li, Wenwei; Ogden, Sarah; Zhu, Fanxiu

    2016-07-01

    Kaposi's sarcoma-associated herpesvirus (KSHV) is the causative agent of three human malignancies. KSHV ORF36 encodes a serine/threonine viral protein kinase, which is conserved throughout all herpesviruses. Although several studies have identified the viral and cellular substrates of conserved herpesvirus protein kinases (CHPKs), the precise functions of KSHV ORF36 during lytic replication remain elusive. Here, we report that ORF36 interacts with another lytic protein, ORF45, in a manner dependent on ORF36 kinase activity. We mapped the regions of ORF36 and ORF45 involved in the binding. Their association appears to be mediated by electrostatic interactions, since deletion of either the highly basic N terminus of ORF36 or an acidic patch of ORF45 abolished the binding. In addition, the dephosphorylation of ORF45 protein dramatically reduced its association with ORF36. Importantly, ORF45 enhances both the stability and kinase activity of ORF36. Consistent with previous studies of CHPK homologs, we detected ORF36 protein in extracellular virions. To investigate the roles of ORF36 in the context of KSHV lytic replication, we used bacterial artificial chromosome mutagenesis to engineer both ORF36-null and kinase-dead mutants. We found that ORF36-null/mutant virions are moderately defective in viral particle production and are further deficient in primary infection. In summary, our results uncover a functionally important interaction between ORF36 and ORF45 and indicate a significant role of ORF36 in the production of infectious progeny virions. Kaposi's sarcoma-associated herpesvirus (KSHV) is a human tumor virus with a significant public health burden. KSHV ORF36 encodes a serine/threonine viral protein kinase, whose functions throughout the viral life cycle have not been elucidated. Here, we report that ORF36 interacts with another KSHV protein, ORF45. We mapped the regions of ORF36 and ORF45 involved in their association and further characterized the consequences

  17. Tissue Specificity of the Kaposi's Sarcoma-Associated Herpesvirus Latent Nuclear Antigen (LANA/orf73) Promoter in Transgenic Mice

    PubMed Central

    Jeong, Joseph H.; Hines-Boykin, Rebecca; Ash, John D.; Dittmer, Dirk P.

    2002-01-01

    Kaposi's sarcoma-associated herpesvirus (KSHV/HHV-8) is a human-oncogenic herpesvirus. Cells from KSHV-associated tumors, such as Kaposi's sarcoma (KS) and primary effusion lymphoma (PEL), are of endothelial and B-cell origin, respectively. KSHV persists indefinitely in these cell lineages during latent infection. Indeed, cellular latency is a hallmark of all herpesviruses that is intimately linked to their pathogenesis. We previously characterized the promoter for the KSHV latency-associated nuclear antigen LANA/orf73. LANA is required for latent episome maintenance and has also been implicated in oncogenesis. Hence, regulation of LANA expression is critical to KSHV persistence. We find that a region extending to bp −1299 upstream of the LANA transcription start site is able to drive lacZ-reporter gene expression in several lines of transgenic mice. In agreement with KSHV's natural tropism, we detected reporter gene expression in CD19-positive B cells but not in CD3-positive T cells. We also detected expression in the kidney and, at a lower level, in the liver. In contrast to KS tumors, transgene expression was localized to kidney tubular epithelium rather than vascular endothelial cells. This suggests that our promoter fragment contains all cis-regulatory elements sufficient for B-cell specificity but not those required for endothelial specificity. Alternatively, while the trans-acting factors required for LANA expression in B cells are evolutionarily conserved, those that regulate endothelial cell-specific expression are unique to humans. Our in vivo studies address a conundrum in KSHV biology: in culture, KSHV is able to infect a variety of cell types indiscriminately, while in healthy latent carriers KSHV is found in B lymphocytes. The transgenic-mouse experiments reported here suggest that tissue-restricted LANA gene expression could explain B-cell-specific viral persistence. PMID:12368345

  18. Parasite infection is associated with Kaposi's sarcoma associated herpesvirus (KSHV) in Ugandan women

    PubMed Central

    2011-01-01

    Background Immune modulation by parasites may influence susceptibility to bacteria and viruses. We examined the association between current parasite infections, HIV and syphilis (measured in blood or stool samples using standard methods) and antibodies against Kaposi's sarcoma herpesvirus (KSHV), measured by ELISA, in 1915 stored plasma samples from pregnant women in Entebbe, Uganda. Results Seroprevalence of KSHV was higher in women with malaria parasitaemia (73% vs 60% p = 0.01), hookworm (67% vs 56% p = 0.001) and Mansonella perstans (69% vs 59% p = 0.05); seroprevalence increased with increasing intensity of hookworm infection (p < 0.001[trend]). No associations were found for HIV, five other parasites or active syphilis. These effects were not explained by socioeconomic status or education. Conclusions Specific parasite infections are associated with presence of antibodies against KSHV, perhaps mediated via their effect on immune function. PMID:21962023

  19. Kaposi's sarcoma-associated herpesvirus-encoded LANA associates with glucocorticoid receptor and enhances its transcriptional activities.

    PubMed

    Togi, Sumihito; Nakasuji, Misa; Muromoto, Ryuta; Ikeda, Osamu; Okabe, Kanako; Kitai, Yuichi; Kon, Shigeyuki; Oritani, Kenji; Matsuda, Tadashi

    2015-07-31

    Kaposi's sarcoma-associated herpesvirus (KSHV)-encoded latency-associated nuclear antigen (LANA), which interacts with cellular proteins, plays a central role in modification of viral and/or cellular gene expression. Here, we show that LANA associates with glucocorticoid receptor (GR), and that LANA enhances the transcriptional activity of GR. Co-immunoprecipitation revealed a physical interaction between LANA and GR in transiently transfected 293T and HeLa cells. In human B-lymphoma cells, LANA overexpression enhanced GR activity and cell growth suppression following glucocorticoid stimulation. Furthermore, confocal microscopy showed that activated GR was bound to LANA and accumulated in the nucleus, leading to an increase in binding of activated GR to the glucocorticoid response element of target genes. Taken together, KSHV-derived LANA acts as a transcriptional co-activator of GR. Our results might suggest a careful use of glucocorticoids in the treatment of patients with KSHV-related malignancies such as Kaposi's sarcoma, primary effusion lymphoma, and multicentric Castleman disease. Copyright © 2015 Elsevier Inc. All rights reserved.

  20. Kaposi΄s sarcoma-associated herpesvirus ORF36 protein induces chromosome condensation and phosphorylation of histone H3.

    PubMed

    Kim, Sunmi; Cha, Seho; Jang, Jun Hyeong; Kim, Yejin; Seo, Taegun

    2013-01-01

    Kaposi΄s sarcoma-associated herpesvirus (KSHV) has been known as an agent causing Kaposi΄s sarcoma, primary effusion lymphoma, and multicentric Castleman΄s disease. In the lytic phase of the virus cycle, various viral genes are expressed, which causes host cell dysregulation. Among the lytic genes, viral protein kinase (vPK) encoded by ORF36 is a member of serine/threonine protein kinase (CHPK) family, which is involved in viral gene expression, viral DNA replication and encapsidation, and nuclear egress of virions. Recent studies have shown that the BGLF4 protein of Epstein-Barr virus (EBV), a member of the CHPK family, alters the host cell chromatin structure through phosphorylation of its key regulators. The role of KSHV ORF36 in cellular mitotic events, however, is not yet understood. In the current study, we showed that KSHV ORF36 induced chromosome condensation and phosphorylation of histone H3 on Ser 10, which are known as cellular mitosis markers. These processes have occurred in a kinase activity-dependent manner.

  1. Identification of an immunoreceptor tyrosine-based activation motif of K1 transforming protein of Kaposi's sarcoma-associated herpesvirus.

    PubMed

    Lee, H; Guo, J; Li, M; Choi, J K; DeMaria, M; Rosenzweig, M; Jung, J U

    1998-09-01

    Kaposi's sarcoma-associated herpesvirus (KSHV) is consistently identified in Kaposi's sarcoma and body cavity-based lymphoma. KSHV encodes a transforming protein called K1 which is structurally similar to lymphocyte receptors. We have found that a highly conserved region of the cytoplasmic domain of K1 resembles the sequence of immunoreceptor tyrosine-based activation motifs (ITAMs). To demonstrate the signal-transducing activity of K1, we constructed a chimeric protein in which the cytoplasmic tail of the human CD8alpha polypeptide was replaced with that of KSHV K1. Expression of the CD8-K1 chimera in B cells induced cellular tyrosine phosphorylation and intracellular calcium mobilization upon stimulation with an anti-CD8 antibody. Mutational analyses showed that the putative ITAM of K1 was required for its signal-transducing activity. Furthermore, tyrosine residues of the putative ITAM of K1 were phosphorylated upon stimulation, and this allowed subsequent binding of SH2-containing proteins. These results demonstrate that the KSHV transforming protein K1 contains a functional ITAM in its cytoplasmic domain and that it can transduce signals to induce cellular activation.

  2. Identification of Novel Kaposi's Sarcoma-Associated Herpesvirus Orf50 Transcripts: Discovery of New RTA Isoforms with Variable Transactivation Potential.

    PubMed

    Wakeman, Brian S; Izumiya, Yoshihiro; Speck, Samuel H

    2017-01-01

    Kaposi's sarcoma-associated herpesvirus (KSHV) is a gammaherpesvirus that has been associated with primary effusion lymphoma and multicentric Castleman's disease, as well as its namesake Kaposi's sarcoma. As a gammaherpesvirus, KSHV is able to acutely replicate, enter latency, and reactivate from this latent state. A key protein involved in both acute replication and reactivation from latency is the replication and transcriptional activator (RTA) encoded by the gene Orf50 RTA is a known transactivator of multiple viral genes, allowing it to control the switch between latency and virus replication. We report here the identification of six alternatively spliced Orf50 transcripts that are generated from four distinct promoters. These newly identified promoters are shown to be transcriptionally active in 293T (embryonic kidney), Vero (African-green monkey kidney epithelial), 3T12 (mouse fibroblast), and RAW 264.7 (mouse macrophage) cell lines. Notably, the newly identified Orf50 transcripts are predicted to encode four different isoforms of the RTA which differ by 6 to 10 residues at the amino terminus of the protein. We show the global viral transactivation potential of all four RTA isoforms and demonstrate that all isoforms can transcriptionally activate an array of KSHV promoters to various levels. The pattern of transcriptional activation appears to support a transcriptional interference model within the Orf50 region, where silencing of previously expressed isoforms by transcription initiation from upstream Orf50 promoters has the potential to modulate the pattern of viral gene activation.

  3. beta-Adrenoreceptors reactivate Kaposi's sarcoma-associated herpesvirus lytic replication via PKA-dependent control of viral RTA.

    PubMed

    Chang, Margaret; Brown, Helen J; Collado-Hidalgo, Alicia; Arevalo, Jesusa M; Galic, Zoran; Symensma, Tonia L; Tanaka, Lena; Deng, Hongyu; Zack, Jerome A; Sun, Ren; Cole, Steve W

    2005-11-01

    Reactivation of Kaposi's sarcoma-associated herpesvirus (KSHV) lytic replication is mediated by the viral RTA transcription factor, but little is known about the physiological processes controlling its expression or activity. Links between autonomic nervous system activity and AIDS-associated Kaposi's sarcoma led us to examine the potential influence of catecholamine neurotransmitters. Physiological concentrations of epinephrine and norepinephrine efficiently reactivated lytic replication of KSHV in latently infected primary effusion lymphoma cells via beta-adrenergic activation of the cellular cyclic AMP/protein kinase A (PKA) signaling pathway. Effects were blocked by PKA antagonists and mimicked by pharmacological and physiological PKA activators (prostaglandin E2 and histamine) or overexpression of the PKA catalytic subunit. PKA up-regulated RTA gene expression, enhanced activity of the RTA promoter, and posttranslationally enhanced RTA's trans-activating capacity for its own promoter and heterologous lytic promoters (e.g., the viral PAN gene). Mutation of predicted phosphorylation targets at RTA serines 525 and 526 inhibited PKA-mediated enhancement of RTA trans-activating capacity. Given the high catecholamine levels at sites of KSHV latency such as the vasculature and lymphoid organs, these data suggest that beta-adrenergic control of RTA might constitute a significant physiological regulator of KSHV lytic replication. These findings also suggest novel therapeutic strategies for controlling the activity of this oncogenic gammaherpesvirus in vivo.

  4. Activation of latent Kaposi's sarcoma-associated herpesvirus by demethylation of the promoter of the lytic transactivator

    PubMed Central

    Chen, Jiguo; Ueda, Keiji; Sakakibara, Shuhei; Okuno, Toshiomi; Parravicini, Carlo; Corbellino, Mario; Yamanishi, Koichi

    2001-01-01

    Kaposi's sarcoma-associated herpesvirus (KSHV) is strongly linked to Kaposi's sarcoma, primary effusion lymphomas, and a subset of multicentric Castleman's disease. The mechanism by which this virus establishes latency and reactivation is unknown. KSHV Lyta (lytic transactivator, also named KSHV/Rta), mainly encoded by the ORF 50 gene, is a lytic switch gene for viral reactivation from latency, inasmuch as it is both essential and sufficient to drive the entire viral lytic cycle. Here we show that the Lyta promoter region was heavily methylated in latently infected cells. Treatment of primary effusion lymphoma-delivered cell lines with tetradecanoylphorbol acetate caused demethylation of the Lyta promoter and induced KSHV lytic phase in vitro. Methylation cassette assay shows demethylation of the Lyta promoter region was essential for the expression of Lyta. In vivo, biopsy samples obtained from patients with KSHV-related diseases show the most demethylation in the Lyta promoter region, whereas samples from a latently infected KSHV carrier remained in a methylated status. These results suggest a relationship among a demethylation status in the Lyta promoter, the reactivation of KSHV, and the development of KSHV-associated diseases. PMID:11274437

  5. Kaposi's sarcoma-associated herpesvirus-encoded LANA associates with glucocorticoid receptor and enhances its transcriptional activities

    SciTech Connect

    Togi, Sumihito; Nakasuji, Misa; Muromoto, Ryuta; Ikeda, Osamu; Okabe, Kanako; Kitai, Yuichi; Kon, Shigeyuki; Oritani, Kenji; Matsuda, Tadashi

    2015-07-31

    Kaposi's sarcoma-associated herpesvirus (KSHV)-encoded latency-associated nuclear antigen (LANA), which interacts with cellular proteins, plays a central role in modification of viral and/or cellular gene expression. Here, we show that LANA associates with glucocorticoid receptor (GR), and that LANA enhances the transcriptional activity of GR. Co-immunoprecipitation revealed a physical interaction between LANA and GR in transiently transfected 293T and HeLa cells. In human B-lymphoma cells, LANA overexpression enhanced GR activity and cell growth suppression following glucocorticoid stimulation. Furthermore, confocal microscopy showed that activated GR was bound to LANA and accumulated in the nucleus, leading to an increase in binding of activated GR to the glucocorticoid response element of target genes. Taken together, KSHV-derived LANA acts as a transcriptional co-activator of GR. Our results might suggest a careful use of glucocorticoids in the treatment of patients with KSHV-related malignancies such as Kaposi's sarcoma, primary effusion lymphoma, and multicentric Castleman disease. - Highlights: • KSHV-LANA enhances the transcriptional activity of GR in 293T and HeLa cells. • KSHV-LANA physically associates with GR. • KSHV-LANA enhances GR activation and cell growth suppression in human B-lymphocytes. • KSHV-LANA influences the nuclear retention and DNA binding activity of GR.

  6. Identification, expression, and immunogenicity of Kaposi's sarcoma-associated herpesvirus-encoded small viral capsid antigen.

    PubMed Central

    Lin, S F; Sun, R; Heston, L; Gradoville, L; Shedd, D; Haglund, K; Rigsby, M; Miller, G

    1997-01-01

    We describe a recombinant antigen for use in serologic tests for antibodies to Kaposi's sarcoma (KS)-associated herpesvirus (KSHV). The cDNA for a small viral capsid antigen (sVCA) was identified by immunoscreening of a library prepared from the BC-1 body cavity lymphoma cell line induced into KSHV lytic gene expression by sodium butyrate. The cDNA specified a 170-amino-acid peptide with homology to small viral capsid proteins encoded by the BFRF3 gene of Epstein-Barr virus and the ORF65 gene of herpesvirus saimiri. KSHV sVCA was expressed from a 0.85-kb mRNA present late in lytic KSHV replication in BC-1 cells. This transcript was sensitive to phosphonoacetic acid and phosphonoformic acid, inhibitors of herpesvirus DNA replication. KSHV sVCA expressed in mammalian cells or Escherichia coli or translated in vitro was recognized as an antigen by antisera from KS patients. Rabbit antisera raised to KSHV sVCA expressed in E. coli detected a 22-kDa protein in KSHV-infected human B cells. Overexpressed KSHV sVCA purified from E. coli and used as an antigen in immunoblot screening assay did not cross-react with EBV BFRF3. Antibodies to sVCA were present in 89% of 47 human immunodeficiency virus (HIV)-positive patients with KS, in 20% of 54 HIV-positive patients without KS, but in none of 122 other patients including children born to HIV-seropositive mothers and patients with hemophilia, autoimmune disease, or nasopharyngeal carcinoma. Low-titer antibody was detected in three sera from 28 healthy subjects. Antibodies to recombinant sVCA correlate with KS in high-risk populations. Recombinant sVCA can be used to examine the seroepidemiology of infection with KSHV in the general population. PMID:9060668

  7. Identification, expression, and immunogenicity of Kaposi's sarcoma-associated herpesvirus-encoded small viral capsid antigen.

    PubMed

    Lin, S F; Sun, R; Heston, L; Gradoville, L; Shedd, D; Haglund, K; Rigsby, M; Miller, G

    1997-04-01

    We describe a recombinant antigen for use in serologic tests for antibodies to Kaposi's sarcoma (KS)-associated herpesvirus (KSHV). The cDNA for a small viral capsid antigen (sVCA) was identified by immunoscreening of a library prepared from the BC-1 body cavity lymphoma cell line induced into KSHV lytic gene expression by sodium butyrate. The cDNA specified a 170-amino-acid peptide with homology to small viral capsid proteins encoded by the BFRF3 gene of Epstein-Barr virus and the ORF65 gene of herpesvirus saimiri. KSHV sVCA was expressed from a 0.85-kb mRNA present late in lytic KSHV replication in BC-1 cells. This transcript was sensitive to phosphonoacetic acid and phosphonoformic acid, inhibitors of herpesvirus DNA replication. KSHV sVCA expressed in mammalian cells or Escherichia coli or translated in vitro was recognized as an antigen by antisera from KS patients. Rabbit antisera raised to KSHV sVCA expressed in E. coli detected a 22-kDa protein in KSHV-infected human B cells. Overexpressed KSHV sVCA purified from E. coli and used as an antigen in immunoblot screening assay did not cross-react with EBV BFRF3. Antibodies to sVCA were present in 89% of 47 human immunodeficiency virus (HIV)-positive patients with KS, in 20% of 54 HIV-positive patients without KS, but in none of 122 other patients including children born to HIV-seropositive mothers and patients with hemophilia, autoimmune disease, or nasopharyngeal carcinoma. Low-titer antibody was detected in three sera from 28 healthy subjects. Antibodies to recombinant sVCA correlate with KS in high-risk populations. Recombinant sVCA can be used to examine the seroepidemiology of infection with KSHV in the general population.

  8. Differential regulation of the overlapping Kaposi's sarcoma-associated herpesvirus vGCR (orf74) and LANA (orf73) promoters.

    PubMed

    Jeong, J; Papin, J; Dittmer, D

    2001-02-01

    Similar to that of other herpesviruses, Kaposi's sarcoma-associated herpesvirus (KSHV/HHV-8) lytic replication destroys the host cell, while the virus can persist in a latent state in synchrony with the host. During latency only a few genes are transcribed, and the question becomes one of what determines latent versus lytic gene expression. Here we undertake a detailed analysis of the latency-associated nuclear antigen (LANA [orf73]) promoter (LANAp). We characterized a minimal region that is necessary and sufficient to maintain high-level transcription in all tissues tested, including primary endothelial cells and B cells, which are the suspected natural host for KSHV. We show that in transient-transfection assays LANAp mimics the expression pattern observed for the authentic promoter in the context of the KSHV episome. Unlike other KSHV promoters tested thus far, LANAp is not affected by tetradecanoyl phorbol acetate or viral lytic cycle functions. It is, however, subject to control by LANA itself and cellular regulatory factors, such as p53. This is in contrast to the K14/vGCR (orf74) promoter, which overlaps LANAp and directs transcription on the opposite strand. We isolated a minimal cis-regulatory region sufficient for K14/vGCR promoter activity and show that it, too, mimics the regulation observed for the authentic viral promoter. In particular, we demonstrate that its activity is absolutely dependent on the immediate-early transactivator orf50, the KSHV homolog of the Epstein-Barr virus Rta transactivator.

  9. Charting Latency Transcripts in Kaposi's Sarcoma-Associated Herpesvirus by Whole-Genome Real-Time Quantitative PCR

    PubMed Central

    Fakhari, Farnaz D.; Dittmer, Dirk P.

    2002-01-01

    The division into a latent or lytic life cycle is fundamental to all herpesviridae. In the case of Kaposi's sarcoma-associated herpesvirus (KSHV) (human herpesvirus 8), latent genes have been implicated in cell autonomous transformation, while certain lytic genes procure a tumor friendly milieu through paracrine mechanism. To query KSHV transcription, we devised and validated a high-throughput, high-specificity, high-sensitivity, real-time quantitative reverse transcription-PCR array. This novel methodology is applicable to many human pathogens. Its first use demonstrated that the mRNA levels for KSHV LANA, v-cyclin, and v-FLIP do not increase at any time after viral reactivation. The mRNA for LANA-2/vIRF-3 is similarly resistant to viral reactivation. In contrast, every other latent or lytic message was induced. Hence, LANA, v-FLIP, v-cyclin, and LANA-2 constitute a group of uniquely regulated transcripts in the KSHV genome. PMID:12021355

  10. Quantitative determinations of anti-Kaposi sarcoma-associated herpesvirus antibody levels in men who have sex with men.

    PubMed

    Gogineni, Emile; Marshall, Vickie; Miley, Wendell; Bayat, Ahmad; Whitby, Denise; Kovacs, Joseph A; Burbelo, Peter D

    2013-05-01

    Infection with Kaposi sarcoma-associated herpesvirus (KSHV; also called human herpesvirus-8) is common among men who have sex with men (MSM). Here, quantitative anti-KSHV antibody levels were measured using luciferase immunoprecipitation systems (LIPS) in an MSM cohort with and without HIV from the NIH Clinical Center. Antibodies were detected using a mixture of 4 KSHV antigens in the MSM cohort and in Kaposi sarcoma (KS) patients. Along with HIV status, these results were compared with K8.1 and ORF73 ELISA, PCR virus detection, and additional LIPS testing. LIPS revealed that 25% (76/307) of the MSM cohort were KSHV seropositive, including 59 HIV+ and 17 HIV- subjects. The anti-KSHV antibody levels detected by LIPS were not statistically different between the KSHV+/HIV+ and KSHV+/HIV- subgroups but were lower than the KS patients (P < 0.0001). ELISA analysis of the MSM cohort detected a 35.5% frequency of KSHV infection and showed agreement with 81% of the samples evaluated by LIPS. Further LIPS testing with v-cyclin, a second ORF73 fragment and ORF38 reconciled some of the differences observed between LIPS and the ELISA immunoassays, and the revised LIPS seroprevalence in the MSM cohort was increased to 31%. Additional quantitative antibody analysis demonstrated statistically lower KSHV antibody levels in MSM compared to KS patients, but no difference was found between KSHV infected with and without HIV coinfection. These findings also suggest that antibodies against v-cyclin and ORF38 are useful for identifying patients with asymptomatic KSHV infection.

  11. Induction of chemokine production by latent Kaposi's sarcoma-associated herpesvirus infection of endothelial cells.

    PubMed

    Xu, Yiyiang; Ganem, Don

    2007-01-01

    Infection with Kaposi's sarcoma (KS)-associated herpesvirus (KSHV) is linked strongly to development of KS, an endothelial neoplasm also characterized by striking neoangiogenesis and infiltration with inflammatory cells. To elucidate the links between endothelial infection and inflammation, primary human umbilical vein endothelial cells (HUVECs) were examined for the production of chemokines following latent KSHV infection. Several chemokines that are produced in the ground state, including MCP-1, NAP 2 and RANTES, are upregulated significantly by KSHV infection. Moreover, the chemokine CXCL16, which is nearly absent in uninfected cells, is induced significantly following infection. This induction is attributable primarily to expression of vFLIP, a known inducer of NF-kappaB. CXCL16 induces the chemotaxis of activated T cells, whose products have been proposed to positively regulate KS tumour-cell survival and growth. Whilst CXCL16 has also been proposed as a direct endothelial chemoattractant and mitogen, neither proliferation nor chemotaxis of HUVECs was observed following CXCL16 exposure. These results suggest that CXCL16 induction by KSHV contributes to the inflammatory phenotype of KS, but plays little role in the recruitment of endothelial spindle cells.

  12. Characterization of the bipartite nuclear localization signal of protein LANA2 from Kaposi's sarcoma-associated herpesvirus.

    PubMed Central

    Muñoz-Fontela, Cesar; Rodríguez, Estefanía; Nombela, Cesar; Arroyo, Javier; Rivas, Carmen

    2003-01-01

    LANA2 is a nuclear latent protein detected exclusively in Kaposi's sarcoma-associated herpesvirus-infected B cells. The protein inhibits p53-dependent transactivation and apoptosis, suggesting an important role in the transforming activity of the virus. To explore the molecular mechanisms of its nuclear localization, fusion proteins of green fluorescent protein (EGFP) and deletion constructs of LANA2 were expressed in HeLa cells. Only the fragment comprising amino acid residues 355-440 of LANA2 localized in the cell nucleus. This fragment contains two closely located basic domains and forms a putative bipartite nuclear localization signal (NLS). The putative LANA2 NLS was able to target EGFP to the nucleus consistently. Site-directed mutation analyses demonstrated that LANA2 contains a functional bipartite NLS between amino acid positions 367 and 384. In addition, analysis of cells transfected with a cytoplasmic LANA2 mutant revealed that an appropriate subcellular localization may be crucial to regulate p53 activity. PMID:12767255

  13. New insights into the expression and functions of the Kaposi's sarcoma-associated herpesvirus long noncoding PAN RNA.

    PubMed

    Conrad, Nicholas K

    2016-01-02

    The Kaposi's sarcoma-associated herpesvirus (KSHV) is a clinically relevant pathogen associated with several human diseases that primarily affect immunocompromised individuals. KSHV encodes a noncoding polyadenylated nuclear (PAN) RNA that is essential for viral propagation and viral gene expression. PAN RNA is the most abundant viral transcript produced during lytic replication. The accumulation of PAN RNA depends on high levels of transcription driven by the Rta protein, a KSHV transcription factor necessary and sufficient for latent-to-lytic phase transition. In addition, KSHV uses several posttranscriptional mechanisms to stabilize PAN RNA. A cis-acting element, called the ENE, prevents PAN RNA decay by forming a triple helix with its poly(A) tail. The viral ORF57 and the cellular PABPC1 proteins further contribute to PAN RNA stability during lytic phase. PAN RNA functions are only beginning to be uncovered, but PAN RNA has been proposed to control gene expression by several different mechanisms. PAN RNA associates with the KSHV genome and may regulate gene expression by recruiting chromatin-modifying factors. Moreover, PAN RNA binds the viral latency-associated nuclear antigen (LANA) protein and decreases its repressive activity by sequestering it from the viral genome. Surprisingly, PAN RNA was found to associate with translating ribosomes, so this noncoding RNA may be additionally used to produce viral peptides. In this review, I highlight the mechanisms of PAN RNA accumulation and describe recent insights into potential functions of PAN RNA.

  14. Promoter switching allows simultaneous transcription of LANA and K14/vGPCR of Kaposi's sarcoma-associated herpesvirus.

    PubMed

    Staudt, Michelle R; Dittmer, Dirk P

    2006-06-20

    Latent transcription of the latency-associated nuclear antigen (LANA/ORF73) of Kaposi's sarcoma-associated herpesvirus is driven by the LANAp-c. Complexity arises during lytic reactivation, however, as the bicistronic K14/vGPCR transcript initiates 32 bp downstream of LANAp-c in the opposite orientation. We identify an Rta/ORF50-inducible LANA promoter (LANAp-i) that is distinct from the LANAp-c. LANAp-c is unaffected by Rta/ORF50. Utilization of the second, downstream LANAp-i explains how LANA and K14/vGPCR are simultaneously transcribed during de novo infection or lytic reactivation. Transactivation of LANAp-i and K14/vGPCRp requires the C-terminal activation domain of Rta/ORF50 and is mediated by DNA-binding-dependent and -independent Rta/ORF50 mechanisms. Transcriptional profiling following viral reactivation support promoter reporter phenotypes. In sum, cis-elements within the LANAp were selected to ensure faithful expression of LANA and other genes regulated by LANAp during all stages of the KSHV lifecycle despite potential interference from K14/vGPCRp activity.

  15. Ribosomal Protein S6 Interacts with the Latency-Associated Nuclear Antigen of Kaposi's Sarcoma-Associated Herpesvirus

    PubMed Central

    Chen, Wuguo; Dittmer, Dirk P.

    2011-01-01

    The latency-associated nuclear antigen (LANA) is central to the maintenance of Kaposi's sarcoma-associated herpesvirus (KSHV) and to the survival of KSHV-carrying tumor cells. In an effort to identify interaction partners of LANA, we purified authentic high-molecular-weight complexes of LANA by conventional chromatography followed by immunoprecipitation from the BC-3 cell line. This is the first analysis of LANA-interacting partners that is not based on forced ectopic expression of LANA. Subsequent tandem mass spectrometry (MS/MS) analysis identified many of the known LANA-interacting proteins. We confirmed LANA's interactions with histones. Three classes of proteins survived our stringent four-step purification procedure (size, heparin, anion, and immunoaffinity chromatography): two heat shock proteins (Hsp70 and Hsp96 precursor), signal recognition particle 72 (SRP72), and 10 different ribosomal proteins. These proteins are likely involved in structural interactions within LANA high-molecular-weight complexes. Here, we show that ribosomal protein S6 (RPS6) interacts with LANA. This interaction is mediated by the N-terminal domain of LANA and does not require DNA or RNA. Depletion of RPS6 from primary effusion lymphoma (PEL) cells dramatically decreases the half-life of full-length LANA. The fact that RPS6 has a well-established nuclear function beyond its role in ribosome assembly suggests that RPS6 (and by extension other ribosomal proteins) contributes to the extraordinary stability of LANA. PMID:21734034

  16. Kaposi's sarcoma-associated herpesvirus ORF57 protein interacts with PYM to enhance translation of viral intronless mRNAs

    PubMed Central

    Boyne, James R; Jackson, Brian R; Taylor, Adam; Macnab, Stuart A; Whitehouse, Adrian

    2010-01-01

    Kaposi's sarcoma-associated herpesvirus (KSHV) expresses numerous intronless mRNAs that are unable to access splicing-dependent cellular mRNA nuclear export pathways. To circumvent this problem, KSHV encodes the open reading frame 57 (ORF57) protein, which orchestrates the formation of an export-competent virus ribonucleoprotein particle comprising the nuclear export complex hTREX, but not the exon-junction complex (EJC). Interestingly, EJCs stimulate mRNA translation, which raises the intriguing question of how intronless KSHV transcripts are efficiently translated. Herein, we show that ORF57 associates with components of the 48S pre-initiation complex and co-sediments with the 40S ribosomal subunits. Strikingly, we observed a direct interaction between ORF57 and PYM, a cellular protein that enhances translation by recruiting the 48S pre-initiation complex to newly exported mRNAs, through an interaction with the EJC. Moreover, detailed biochemical analysis suggests that ORF57 recruits PYM to intronless KSHV mRNA and PYM then facilitates the association of ORF57 and the cellular translation machinery. We, therefore, propose a model whereby ORF57 interacts directly with PYM to enhance translation of intronless KSHV transcripts. PMID:20436455

  17. Kaposi's Sarcoma-Associated Herpesvirus Utilizes and Manipulates RNA N(6)-Adenosine Methylation To Promote Lytic Replication.

    PubMed

    Ye, Fengchun; Chen, E Ricky; Nilsen, Timothy W

    2017-08-15

    N(6)-adenosine methylation (m(6)A) is the most common posttranscriptional RNA modification in mammalian cells. We found that most transcripts encoded by the Kaposi's sarcoma-associated herpesvirus (KSHV) genome undergo m(6)A modification. The levels of m(6)A-modified mRNAs increased substantially upon stimulation for lytic replication. The blockage of m(6)A inhibited splicing of the pre-mRNA encoding the replication transcription activator (RTA), a key KSHV lytic switch protein, and halted viral lytic replication. We identified several m(6)A sites in RTA pre-mRNA crucial for splicing through interactions with YTH domain containing 1 (YTHDC1), an m(6)A nuclear reader protein, in conjunction with serine/arginine-rich splicing factor 3 (SRSF3) and SRSF10. Interestingly, RTA induced m(6)A and enhanced its own pre-mRNA splicing. Our results not only demonstrate an essential role of m(6)A in regulating RTA pre-mRNA splicing but also suggest that KSHV has evolved a mechanism to manipulate the host m(6)A machinery to its advantage in promoting lytic replication.IMPORTANCE KSHV productive lytic replication plays a pivotal role in the initiation and progression of Kaposi's sarcoma tumors. Previous studies suggested that the KSHV switch from latency to lytic replication is primarily controlled at the chromatin level through histone and DNA modifications. The present work reports for the first time that KSHV genome-encoded mRNAs undergo m(6)A modification, which represents a new mechanism at the posttranscriptional level in the control of viral replication. Copyright © 2017 American Society for Microbiology.

  18. Differential Regulation of the Overlapping Kaposi's Sarcoma-Associated Herpesvirus vGCR (orf74) and LANA (orf73) Promoters

    PubMed Central

    Jeong, Joseph; Papin, James; Dittmer, Dirk

    2001-01-01

    Similar to that of other herpesviruses, Kaposi's sarcoma-associated herpesvirus (KSHV/HHV-8) lytic replication destroys the host cell, while the virus can persist in a latent state in synchrony with the host. During latency only a few genes are transcribed, and the question becomes one of what determines latent versus lytic gene expression. Here we undertake a detailed analysis of the latency-associated nuclear antigen (LANA [orf73]) promoter (LANAp). We characterized a minimal region that is necessary and sufficient to maintain high-level transcription in all tissues tested, including primary endothelial cells and B cells, which are the suspected natural host for KSHV. We show that in transient-transfection assays LANAp mimics the expression pattern observed for the authentic promoter in the context of the KSHV episome. Unlike other KSHV promoters tested thus far, LANAp is not affected by tetradecanoyl phorbol acetate or viral lytic cycle functions. It is, however, subject to control by LANA itself and cellular regulatory factors, such as p53. This is in contrast to the K14/vGCR (orf74) promoter, which overlaps LANAp and directs transcription on the opposite strand. We isolated a minimal cis-regulatory region sufficient for K14/vGCR promoter activity and show that it, too, mimics the regulation observed for the authentic viral promoter. In particular, we demonstrate that its activity is absolutely dependent on the immediate-early transactivator orf50, the KSHV homolog of the Epstein-Barr virus Rta transactivator. PMID:11160678

  19. Reduced seroprevalence of Kaposi's sarcoma-associated herpesvirus (KSHV), human herpesvirus 8 (HHV8), related to suppression of Anopheles density in Italy.

    PubMed

    Coluzzi, M; Calabrò, M L; Manno, D; Chieco-Bianchi, L; Schulz, T F; Ascoli, V

    2003-12-01

    In two formerly malarious parts of Italy, age-related seroprevalence rates of Kaposi's sarcoma-associated herpesvirus [human herpesvirus 8 (KSHV/HHV8)] were determined from local blood donors and correlated with periods of vector control during anti-malaria campaigns. In Veneto, decreased KSHV/HHV8 seroprevalence in the 1951-1955 birth cohort coincides with the peak of DDT house-spraying. In Sardinia, where larviciding augmented indoor DDT-spraying, a significant drop of KSHV/HHV8 seroprevalence between 1945 and 1950 and 1951-1955 birth cohorts (P = 0.0046) coincides with suppression of the malaria vector Anopheles labranchiae Falleroni (Diptera: Culicidae). These results are consistent with age-related association between KSHV/HHV8 seroprevalence rates in native/resident populations and the density of malaria vectors in Veneto and Sardinia. This example supports our 'promoter arthropod' hypothesis on the role of haematophagous insects [putatively blackflies (Simuliidae), sandflies (Phlebotominae) and biting midges (Ceratopogonidae), as well as mosquitoes] when their bites induce hypersensitivity and immunosuppression, potentiate KSHV/HHV8 transmission via human saliva (when insect bite lesions are licked by another person whose saliva carries the virus) and may facilitate Kaposi's sarcoma.

  20. Glycolysis, Glutaminolysis, and Fatty Acid Synthesis Are Required for Distinct Stages of Kaposi's Sarcoma-Associated Herpesvirus Lytic Replication.

    PubMed

    Sanchez, Erica L; Pulliam, Thomas H; Dimaio, Terri A; Thalhofer, Angel B; Delgado, Tracie; Lagunoff, Michael

    2017-05-15

    Kaposi's sarcoma-associated herpesvirus (KSHV) is the etiologic agent of Kaposi's sarcoma (KS). KSHV infection induces and requires multiple metabolic pathways, including the glycolysis, glutaminolysis, and fatty acid synthesis (FAS) pathways, for the survival of latently infected endothelial cells. To determine the metabolic requirements for productive KSHV infection, we induced lytic replication in the presence of inhibitors of different metabolic pathways. We found that glycolysis, glutaminolysis, and FAS are all required for maximal KSHV virus production and that these pathways appear to participate in virus production at different stages of the viral life cycle. Glycolysis and glutaminolysis, but not FAS, inhibit viral genome replication and, interestingly, are required for different early steps of lytic gene expression. Glycolysis is necessary for early gene transcription, while glutaminolysis is necessary for early gene translation but not transcription. Inhibition of FAS resulted in decreased production of extracellular virions but did not reduce intracellular genome levels or block intracellular virion production. However, in the presence of FAS inhibitors, the intracellular virions are noninfectious, indicating that FAS is required for virion assembly or maturation. KS tumors support both latent and lytic KSHV replication. Previous work has shown that multiple cellular metabolic pathways are required for latency, and we now show that these metabolic pathways are required for efficient lytic replication, providing novel therapeutic avenues for KS tumors.IMPORTANCE KSHV is the etiologic agent of Kaposi's sarcoma, the most common tumor of AIDS patients. KS spindle cells, the main tumor cells, all contain KSHV, mostly in the latent state, during which there is limited viral gene expression. However, a percentage of spindle cells support lytic replication and production of virus and these cells are thought to contribute to overall tumor formation. Our previous

  1. Trends in Kaposi's sarcoma-associated Herpesvirus antibodies prior to the development of HIV-associated Kaposi's sarcoma: A nested case-control study

    PubMed Central

    Wakeham, Katie; Johnston, W Thomas; Nalwoga, Angela; Webb, Emily L; Mayanja, Billy N; Miley, Wendell; Elliott, Alison M; Whitby, Denise; Newton, Robert

    2015-01-01

    HIV-associated Kaposi's sarcoma (KS) is a public health challenge in sub-Saharan Africa since both the causative agent, Kaposi's sarcoma associated-herpesvirus (KSHV), and the major risk factor, HIV, are prevalent. In a nested case-control study within a long-standing clinical cohort in rural Uganda, we used stored sera to examine the evolution of antibody titres against the KSHV antigens K8.1 and latency-associated nuclear antigen (LANA) among 30 HIV-infected subjects who subsequently developed HIV-related KS (cases) and among 108 matched HIV/KSHV coinfected controls who did not develop KS. Throughout the 6 years prior to diagnosis, antibody titres to K8.1 and LANA were significantly higher among cases than controls (p < 0.0001), and titres increased prior to diagnosis in the cases. K8.1 titres differed more between KS cases and controls, compared to LANA titres. These differences in titre between cases and controls suggest a role for lytic viral replication in the pathogenesis of HIV-related KS in this setting. PMID:25395177

  2. Kaposi's sarcoma-associated herpesvirus-G protein-coupled receptor-expressing endothelial cells exhibit reduced migration and stimulated chemotaxis by chemokine inverse agonists.

    PubMed

    Couty, Jean-Pierre; Lupu-Meiri, Monica; Oron, Yoram; Gershengorn, Marvin C

    2009-06-01

    A constitutively active G protein-coupled receptor (GPCR) encoded by Kaposi's sarcoma-associated herpesvirus (human herpesvirus-8) (KSHV) is expressed in endothelial (spindle) cells of Kaposi's sarcoma lesions. In this study, we report novel effects of basal signaling by this receptor and of inverse agonist chemokines on migration of KSHV-GPCR-expressing mouse lung endothelial cells. We show that basal signaling by KSHV-GPCR inhibits migration of endothelial cells in two systems, movement through porous filters and in vitro wound closure. Naturally occurring chemokines, interferon gamma-inducible protein-10 and stromal-derived factor-1, which act as inverse agonists at KSHV-GPCR, abrogate the inhibition of migration and stimulate directed migration (or chemotaxis) of these cells. Thus, the expression of KSHV-GPCR may allow infected endothelial cells in situ to remain in a localized environment or to directionally migrate along a gradient of specific chemokines that are inverse agonists at KSHV-GPCR.

  3. Induction of lytic cycle replication of Kaposi's sarcoma-associated herpesvirus by herpes simplex virus type 1: involvement of IL-10 and IL-4.

    PubMed

    Qin, Di; Zeng, Yi; Qian, Chao; Huang, Zan; Lv, Zhigang; Cheng, Lin; Yao, Shuihong; Tang, Qiao; Chen, Xiuying; Lu, Chun

    2008-03-01

    Previously, we identified that both human herpesvirus 6 and human immunodeficiency virus type 1 Tat were important cofactors that activated lytic cycle replication of Kaposi's sarcoma-associated herpesvirus (KSHV). Here, we further investigated the potential of herpes simplex virus type 1 (HSV-1) to influence KSHV replication. We demonstrated that HSV-1 was a potentially important factor in the pathogenesis of Kaposi's sarcoma, as determined by production of lytic phase mRNA transcripts, viral proteins and infectious viral particles in BCBL-1 cells. These results were further confirmed by an RNA interference experiment using small interfering RNA targeting KSHV ORF50 and a luciferase reporter assay testing ORF50 promoter-driven luciferase activity. Finally, we discovered that production of human interleukin-10 (IL-10) and IL-4 partially contributed to HSV-1-induced KSHV replication. Our data present the first direct evidence that HSV-1 can activate KSHV lytic replication and suggest a role of HSV-1 in KSHV pathogenesis.

  4. Prevalence of Kaposi's sarcoma-associated herpesvirus infection in sex workers and women from the general population in Spain.

    PubMed

    de Sanjosé, Sílvia; Marshall, Vickie; Solà, Judit; Palacio, Virgilio; Almirall, Rosa; Goedert, James J; Bosch, F Xavier; Whitby, Denise

    2002-03-01

    Transmission routes of Kaposi's sarcoma-associated herpesvirus (KSHV) in the general population are poorly understood. Whereas sexual transmission appears to be common in homosexual men, the evidence for heterosexual transmission is less convincing. In our study, prevalence of KSHV infection was examined among women in the Spanish general population and among sex workers. Subjects consisted of 100 prostitutes and 100 women randomly sampled from the general population and age-matched to the prostitutes. Women had a personal interview and gynecologic examinations in which a blood sample, cervical cells and oral cells were obtained. Peripheral blood mononuclear cells (PBMC), oral and cervical samples were tested for KSHV DNA by quantitative real-time PCR. Sera were tested for antibodies against human immunodeficiency virus (HIV) by ELISA and against KSHV by latent IFA and K8.1 ELISA. Women who were positive in either serologic assay or PCR were considered infected by KSHV. Human papillomavirus (HPV) DNA in cervical scrapes were evaluated using the Hybrid Capture System. The study population had an average age of 30 years and were HIV-negative. Women from the general population were largely of Spanish nationality, and 61% reported lifetime monogamy. The majority of the prostitutes (76%) were immigrants, primarily from South America. Sex workers were twice as likely to be infected with KSHV than women in the general population (16% vs. 8%, prevalence odds ratio [OR] = 2.2). KSHV was more prevalent among HPV DNA-positive women (OR = 2.5) and among women with an early age at first sexual intercourse (OR = 2.7, p < 0.05). KSHV DNA was detected by PCR in 3% of the oral cavity samples, in 2% of the cervical samples of the prostitutes and in 1% of the cervical samples of women in the general population. All PBMC samples were negative. These results suggest that in low-risk countries for KSHV, oral shedding and heterosexual contacts are potential pathways for KSHV transmission.

  5. Was Kaposi's sarcoma-associated herpesvirus introduced into China via the ancient Silk Road? An evolutionary perspective.

    PubMed

    Liu, Zhenqiu; Fang, Qiwen; Zuo, Jialu; Minhas, Veenu; Wood, Charles; He, Na; Zhang, Tiejun

    2017-07-07

    Kaposi's sarcoma-associated herpesvirus (KSHV) has become widely dispersed worldwide since it was first reported in 1994, but the seroprevalence of KSHV varies geographically. KSHV is relatively ubiquitous in Mediterranean areas and the Xinjiang Uygur Autonomous Region, China. The origin of KSHV has long been puzzling. In the present study, we collected and analysed 154 KSHV ORF-K1 sequences obtained from samples originating from Xinjiang, Italy, Greece, Iran and southern Siberia using Bayesian evolutionary analysis in BEAST to test the hypothesis that KSHV was introduced into Xinjiang via the ancient Silk Road. According to the phylogenetic analysis, 72 sequences were subtype A and 82 subtype C, with C2 (n = 56) being the predominant subtype. The times to the most recent common ancestors (tMRCAs) of KSHV were 29,872 years (95% highest probability density [HPD], 26,851-32,760 years) for all analysed sequences and 2037 years (95% HPD, 1843-2229 years) for Xinjiang sequences in particular. The tMRCA of Xinjiang KSHV was exactly matched with the time period of the ancient Silk Road approximately two thousand years ago. This route began in Chang'an, the capital of the Han dynasty of China, and crossed Central Asia, ending in the Roman Empire. The evolution rate of KSHV was slow, with 3.44 × 10(-6) substitutions per site per year (95% HPD, 2.26 × 10(-6) to 4.71 × 10(-6)), although 11 codons were discovered to be under positive selection pressure. The geographic distances from Italy to Iran and Xinjiang are more than 4000 and 7000 kilometres, respectively, but no explicit relationship between genetic distance and geographic distance was detected.

  6. Identification of Host-Chromosome Binding Sites and Candidate Gene Targets for Kaposi's Sarcoma-Associated Herpesvirus LANA

    PubMed Central

    Lu, Fang; Tsai, Kevin; Chen, Horng-Shen; Wikramasinghe, Priyankara; Davuluri, Ramana V.; Showe, Louise; Domsic, John; Marmorstein, Ronen

    2012-01-01

    LANA is essential for tethering the Kaposi's sarcoma-associated herpesvirus (KSHV) genome to metaphase chromosomes and for modulating host-cell gene expression, but the binding sites in the host-chromosome remain unknown. Here, we use LANA-specific chromatin immunoprecipitation coupled with high-throughput sequencing (ChIP-Seq) to identify LANA binding sites in the viral and host-cell genomes of a latently infected pleural effusion lymphoma cell line BCBL1. LANA bound with high occupancy to the KSHV genome terminal repeats (TR) and to a few minor binding sites in the KSHV genome, including the LANA promoter region. We identified 256 putative LANA binding site peaks with P < 0.01 and overlap in two independent ChIP-Seq experiments. We validated several of the high-occupancy binding sites by conventional ChIP assays and quantitative PCR. Candidate cellular LANA binding motifs were identified and assayed for binding to purified recombinant LANA protein in vitro but bound with low affinity compared to the viral TR binding site. More than half of the LANA binding sites (170/256) could be mapped to within 2.5 kb of a cellular gene transcript. Pathways and Gene Ontogeny (GO) analysis revealed that LANA binds to genes within the p53 and tumor necrosis factor (TNF) regulatory network. Further analysis revealed partial overlap of LANA and STAT1 binding sites in several gamma interferon (IFN-γ)-regulated genes. We show that ectopic expression of LANA can downmodulate IFN-γ-mediated activation of a subset of genes, including the TAP1 peptide transporter and proteasome subunit beta type 9 (PSMB9), both of which are required for class I antigen presentation. Our data provide a potential mechanism through which LANA may regulate several host cell pathways by direct binding to gene regulatory elements. PMID:22419807

  7. Activation of the Kaposi's Sarcoma-Associated Herpesvirus Major Latency Locus by the Lytic Switch Protein RTA (ORF50)

    PubMed Central

    Matsumura, Satoko; Fujita, Yuriko; Gomez, Evan; Tanese, Naoko; Wilson, Angus C.

    2005-01-01

    Kaposi's sarcoma-associated herpesvirus (KSHV) maintains a latent infection in primary effusion lymphoma cells but can be induced to enter full lytic replication by exposure to a variety of chemical inducing agents or by expression of the KSHV-encoded replication and transcription activator (RTA) protein. During latency, only a few viral genes are expressed, and these include the three genes of the so-called latency transcript (LT) cluster: v-FLIP (open reading frame 71 [ORF71]), v-cyclin (ORF72), and latency-associated nuclear antigen (ORF73). During latency, all three open reading frames are transcribed from a common promoter as part of a multicistronic mRNA. Subsequent alternative mRNA splicing and internal ribosome entry allows for the expression of each protein. Here, we show that transcription of LT cassette mRNA can be induced by RTA through the activation of a second promoter (LTi) immediately downstream of the constitutively active promoter (LTc). We identified a minimal cis-regulatory region, which overlaps with the promoter for the bicistronic K14/v-GPCR delayed early gene that is transcribed in the opposite direction. In addition to a TATA box at −30 relative to the LTi mRNA start sites, we identified three separate RTA response elements that are also utilized by the K14/v-GPCR promoter. Interestingly, LTi is unresponsive to sodium butyrate, a potent inducer of lytic replication. This suggests there is a previously unrecognized class of RTA-responsive promoters that respond to direct, but not indirect, induction of RTA. These studies highlight the fact that induction method can influence the precise program of viral gene expression during early events in reactivation and also suggest a mechanism by which RTA contributes to establishment of latency during de novo infections. PMID:15956592

  8. Kaposi's Sarcoma-Associated Herpesvirus RTA Promotes Degradation of the Hey1 Repressor Protein through the Ubiquitin Proteasome Pathway▿

    PubMed Central

    Gould, Faye; Harrison, Sally M.; Hewitt, Eric W.; Whitehouse, Adrian

    2009-01-01

    The Kaposi's sarcoma-associated herpesvirus (KSHV) replication and transcription activator (RTA) protein regulates the latent-lytic switch by transactivating a variety of KSHV lytic and cellular promoters. RTA is a novel E3 ubiquitin ligase that targets a number of transcriptional repressor proteins for degradation by the ubiquitin proteasome pathway. Herein, we show that RTA interacts with the cellular transcriptional repressor protein Hey1. We demonstrate that Hey1 is a target for RTA-mediated ubiquitination and is subsequently degraded by the proteasome. Moreover, a Cys-plus-His-rich region within RTA is important for RTA-mediated degradation of Hey1. We confirm that Hey1 represses the RTA promoter and, furthermore, show that Hey1 binds to the RTA promoter. An interaction was observed between Hey1 and the corepressor mSin3A, and this interaction was abolished in the presence of RTA. Additionally, mSin3A associated with the RTA promoter in nonreactivated, but not reactivated, BCBL1 cells. Small interfering RNA knockdown of Hey1 in HEK 293T cells latently infected with the recombinant virus rKSHV.219 led to increased levels of RTA expression upon reactivation but was insufficient to induce complete lytic reactivation. These results suggest that other additional transcriptional repressors are also important in maintenance of KSHV latency. Taken together, our results suggest that Hey1 has a contributory role in the maintenance of KSHV latency and that disruption of the Hey1 repressosome by RTA-targeted degradation may be one step in the mechanism to regulate lytic reactivation. PMID:19369342

  9. Regulation of the Abundance of Kaposi's Sarcoma-Associated Herpesvirus ORF50 Protein by Oncoprotein MDM2.

    PubMed

    Chang, Tzu-Hsuan; Wang, Shie-Shan; Chen, Lee-Wen; Shih, Ying-Ju; Chang, Li-Kwan; Liu, Shih-Tung; Chang, Pey-Jium

    2016-10-01

    The switch between latency and the lytic cycle of Kaposi's sarcoma-associated herpesvirus (KSHV) is controlled by the expression of virally encoded ORF50 protein. Thus far, the regulatory mechanism underlying the protein stability of ORF50 is unknown. Our earlier studies have demonstrated that a protein abundance regulatory signal (PARS) at the ORF50 C-terminal region modulates its protein abundance. The PARS region consists of PARS-I (aa 490-535) and PARS-II (aa 590-650), and mutations in either component result in abundant expression of ORF50. Here, we show that ORF50 protein is polyubiquitinated and its abundance is controlled through the proteasomal degradation pathway. The PARS-I motif mainly functions as a nuclear localization signal in the control of ORF50 abundance, whereas the PARS-II motif is required for the binding of ubiquitin enzymes in the nucleus. We find that human oncoprotein MDM2, an ubiquitin E3 ligase, is capable of interacting with ORF50 and promoting ORF50 degradation in cells. The interaction domains between both proteins are mapped to the PARS region of ORF50 and the N-terminal 220-aa region of MDM2. Additionally, we identify lysine residues at positions 152 and 154 in the N-terminal domain of ORF50 critically involved in MDM2-mediated downregulation of ORF50 levels. Within KSHV-infected cells, the levels of MDM2 were greatly reduced during viral lytic cycle and genetic knockdown of MDM2 in these cells favored the enhancement of ORF50 expression, supporting that MDM2 is a negative regulator of ORF50 expression. Collectively, the study elucidates the regulatory mechanism of ORF50 stability and implicates that MDM2 may have a significant role in the maintenance of viral latency by lowering basal level of ORF50.

  10. Constitutively active K-cyclin/cdk6 kinase in Kaposi sarcoma-associated herpesvirus-infected cells.

    PubMed

    Van Dross, Rukiyah; Yao, Shan; Asad, Shaheena; Westlake, Grant; Mays, Deborah J; Barquero, Laura; Duell, Stephanie; Pietenpol, Jennifer A; Browning, Philip J

    2005-05-04

    Kaposi sarcoma-associated human herpesvirus (KSHV) encodes K-cyclin, a homologue of D-type cellular cyclins, which binds cyclin-dependent kinases to phosphorylate various substrates. K-cyclin/cdk phosphorylates a subset of substrates normally targeted by cyclins D, E, and A. We used cells naturally infected with KSHV to further characterize the biochemical features of K-cyclin. We used immunoprecipitation with K-cyclin antibodies to examine the association of K-cyclin with cdk2, cdk6, p21Cip1, and p27Kip1 proteins in BC3 cells. We separated populations of BC3 cells enriched in cells in G1, S, or G2/M phases by elutriation and measured K-cyclin protein and the kinase activity of K-cyclin/cdk6 complexes. The half-life of K-cyclin and cyclin D2 proteins was determined by blocking protein synthesis with cycloheximide and measuring proteins in cell lysates by western blot analysis. We fused the entire K-cyclin sequence to the carboxyl-terminal sequence of cellular cyclin D that contains the PEST degradation sequence to produce K-cyclin/D2 and transfected K-cyclin/D2 into K-cyclin-negative cells to investigate the effect of the PEST sequence on K-cyclin's stability. Viral K-cyclin interacted with cyclin-dependent kinases cdk2, cdk4, and cdk6 and with the cyclin/cdk inhibitory proteins p21Cip1 and p27Kip1 in BC3 cell lysates. Unlike D-type cyclins, whose expression is cell cycle dependent, the level of K-cyclin was stable throughout the cell cycle, and the kinase associated with the K-cyclin/cdk6 complex was constitutively active. The half-life of K-cyclin (6.9 hours) was much longer than that of cellular cyclin D2 (0.6 hour) and that of K-cyclin/D2 (0.5 hour), probably because K-cyclin lacks the PEST degradation sequence present in D-type cyclins. The constitutive activation of K-cyclin/cdk complexes in KSHV-infected cells appears to result from the extended half-life of K-cyclin and may explain its role in Kaposi sarcoma.

  11. Expression of the Antisense-to-Latency Transcript Long Noncoding RNA in Kaposi's Sarcoma-Associated Herpesvirus.

    PubMed

    Schifano, Jason M; Corcoran, Kathleen; Kelkar, Hemant; Dittmer, Dirk P

    2017-02-15

    The regulation of latency is central to herpesvirus biology. Recent transcriptome-wide surveys have uncovered evidence for promiscuous transcription across the entirety of the Kaposi's sarcoma-associated herpesvirus (KSHV) genome and postulated the existence of multiple viral long noncoding RNAs (lncRNAs). Next-generation sequencing studies are highly dependent on the specific experimental approach and particular algorithms of analysis and therefore benefit from independent confirmation of the results. The antisense-to-latency transcript (ALT) lncRNA was discovered by genome-tiling microarray (Chandriani et al., J Virol 86:7934-7942, 2010, https://doi.org/10.1128/JVI.00645-10). To characterize ALT in detail, we physically isolated this lncRNA by a strand-specific hybrid capture assay and then employed transcriptome sequencing and novel reverse transcription-PCR (RT-PCR) assays to distinguish all RNA species in the KSHV latency region. These methods confirm that ALT initiates at positions 120739/121012 and encodes a single splice site, which is shared with the 3'-coterminal K14-vGPCR/ORF74 mRNA, terminating at 130873 (GenBank accession number GQ994935), resulting in an ∼10,000-nucleotide transcript. No shorter ALT isoforms were identified. This study also identified a novel intron within the LANA 5' untranslated region using a splice acceptor at 127888. In summary, ALT joins PAN/nut1/T1.1 as a bona fide lncRNA of KSHV with potentially important roles in viral gene regulation and pathogenesis. Increasing data support the importance of noncoding RNAs (ncRNAs), including microRNAs (miRNAs) and lncRNAs, which have been shown to exert critical regulatory functions without coding for recognizable proteins. Defining the sequences of these ncRNAs is essential for future studies aiming to functionally characterize a specific ncRNA. Most lncRNA studies are highly dependent on high-throughput sequencing and bioinformatic analyses, few studies follow up on the initial

  12. Rapid Multiplexed Immunoassay for Detection of Antibodies to Kaposi's Sarcoma-Associated Herpesvirus.

    PubMed

    Logan, Cathy; Todorof, Kathryn; Fiorillo, Suzanne P; Campbell, Thomas B; Elder, John H; Borok, Margaret; Gudza, Ivy; Gwanzura, Lovemore; Ndemera, Buxton; Lochhead, Michael J; Benson, Constance A; Schooley, Robert T

    Diagnosis of KSHV-infected individuals remains a challenge. KSHV prevalence is high in several populations with high prevalence of HIV, leading to increased risk of development of Kaposi's sarcoma (KS). While current assays are reliable for detecting antibodies to KSHV, none are routinely utilized to identify individuals with KSHV infection and thus at increased risk for KS due to assay complexity, lack of access to testing, and cost, particularly in resource-limited settings. Here we describe the addition of KSHV proteins LANA and K8.1 to a previously evaluated HIV/co-infection multiplexed fluorescence immunoassay system. This study demonstrates assay performance by measuring antibody reactivity for KSHV and HIV-1 in a collection of clinical specimens from patients with biopsy-proven KS and sourced negative controls. The KSHV assay correctly identified 155 of 164 plasma samples from patients with biopsy-proven KS and 85 of 93 KSHV antibody (Ab)-negative samples for a sensitivity of 95.1% and specificity of 91.4%. Assay performance for HIV-1 detection was also assessed with 100% agreement with independently verified HIV-1 Ab-positive and Ab-negative samples. These results demonstrate good sensitivity and specificity for detection of antibody to KSHV antigens, and demonstrate the potential for multiplexed co-infection testing in resource-limited settings to identify those at increased risk for HIV-1-related complications.

  13. Complete Genome Sequence of Pig-Tailed Macaque Rhadinovirus 2 and Its Evolutionary Relationship with Rhesus Macaque Rhadinovirus and Human Herpesvirus 8/Kaposi's Sarcoma-Associated Herpesvirus

    PubMed Central

    Bruce, A. Gregory; Thouless, Margaret E.; Haines, Anthony S.; Pallen, Mark J.; Grundhoff, Adam

    2015-01-01

    ABSTRACT Two rhadinovirus lineages have been identified in Old World primates. The rhadinovirus 1 (RV1) lineage consists of human herpesvirus 8, Kaposi's sarcoma-associated herpesvirus (KSHV), and closely related rhadinoviruses of chimpanzees, gorillas, macaques and other Old World primates. The RV2 rhadinovirus lineage is distinct and consists of closely related viruses from the same Old World primate species. Rhesus macaque rhadinovirus (RRV) is the RV2 prototype, and two RRV isolates, 26-95 and 17577, were sequenced. We determined that the pig-tailed macaque RV2 rhadinovirus, MneRV2, is highly associated with lymphomas in macaques with simian AIDS. To further study the role of rhadinoviruses in the development of lymphoma, we sequenced the complete genome of MneRV2 and identified 87 protein coding genes and 17 candidate microRNAs (miRNAs). A strong genome colinearity and sequence homology were observed between MneRV2 and RRV26-95, although the open reading frame (ORF) encoding the KSHV ORFK15 homolog was disrupted in RRV26-95. Comparison with MneRV2 revealed several genomic anomalies in RRV17577 that were not present in other rhadinovirus genomes, including an N-terminal duplication in ORF4 and a recombinative exchange of more distantly related homologs of the ORF22/ORF47 interacting glycoprotein genes. The comparison with MneRV2 has revealed novel genes and important conservation of protein coding domains and transcription initiation, termination, and splicing signals, which have added to our knowledge of RV2 rhadinovirus genetics. Further comparisons with KSHV and other RV1 rhadinoviruses will provide important avenues for dissecting the biology, evolution, and pathology of these closely related tumor-inducing viruses in humans and other Old World primates. IMPORTANCE This work provides the sequence characterization of MneRV2, the pig-tailed macaque homolog of rhesus rhadinovirus (RRV). MneRV2 and RRV belong to the rhadinovirus 2 (RV2) rhadinovirus lineage of

  14. The lytic transcriptome of Kaposi's sarcoma-associated herpesvirus reveals extensive transcription of noncoding regions, including regions antisense to important genes.

    PubMed

    Chandriani, Sanjay; Xu, Yiyang; Ganem, Don

    2010-08-01

    Genomewide analyses of the mammalian transcriptome have revealed that large tracts of sequence previously annotated as noncoding are frequently transcribed and give rise to stable RNA. Although the transcription of individual genes of the Kaposi's sarcoma-associated herpesvirus (KSHV) has been well studied, little is known of the architecture of the viral transcriptome on a genomewide scale. Here we have employed a genomewide tiling array to examine the lytic transcriptome of the Kaposi's sarcoma-associated herpesvirus, KSHV. Our results reveal that during lytic growth (but not during latency), there is extensive transcription from noncoding regions, including both intergenic regions and, especially, noncoding regions antisense to known open reading frames (ORFs). Several of these transcripts have been characterized in more detail, including (i) a 10-kb RNA antisense to the major latency locus, including many of its microRNAs as well as its ORFs; (ii) a 17-kb RNA antisense to numerous ORFs at the left-hand end of the genome; and (iii) a 0.7-kb RNA antisense to the viral homolog of interleukin-6 (vIL-6). These studies indicate that the lytic herpesviral transcriptome resembles a microcosm of the host transcriptome and provides a useful system for the study of noncoding RNAs.

  15. A microRNA Encoded by Kaposi Sarcoma-Associated Herpesvirus Promotes B-Cell Expansion In Vivo

    PubMed Central

    Dahlke, Christine; Maul, Katrin; Christalla, Thomas; Walz, Nicole; Schult, Philipp; Stocking, Carol; Grundhoff, Adam

    2012-01-01

    The human gammaherpesvirus Kaposi sarcoma-associated herpesvirus is strongly linked to neoplasms of endothelial and B-cell origin. The majority of tumor cells in these malignancies are latently infected, and latency genes are consequently thought to play a critical role in virus-induced tumorigenesis. One such factor is kshv-miR-K12-11, a viral microRNA that is constitutively expressed in cell lines derived from KSHV-associated tumors, and that shares perfect homology of its seed sequence with the cellular miR-155. Since miR-155 is overexpressed in a number of human tumors, it is conceivable that mimicry of miR-155 by miR-K12-11 may contribute to cellular transformation in KSHV-associated disease. Here, we have performed a side-by-side study of phenotypic alterations associated with constitutive expression of either human miR-155 or viral miR-K12-11 in bone marrow-derived hematopoietic stem cells. We demonstrate that retroviral-mediated gene transfer and hematopoietic progenitor cell transplantation into C57BL/6 mice leads to increased B-cell fractions in lymphoid organs, as well as to enhanced germinal center formation in both microRNA-expressing mouse cohorts. We furthermore identify Jarid2, a component of Polycomb repressive complex 2, as a novel validated target of miR-K12-11, and confirm its downregulation in miR-K12-11 as well as miR-155 expressing bone marrow cells. Our findings confirm and extend previous observations made in other mouse models, and underscore the notion that miR-K12-11 may have arisen to mimic miR-155 functions in KSHV-infected B-cells. The expression of miR-K12-11 may represent one mechanism by which KSHV presumably aims to reprogram naïve B-cells towards supporting long-term latency, which at the same time is likely to pre-dispose infected lymphocytes to malignant transformation. PMID:23185331

  16. Identification of the Essential Role of Viral Bcl-2 for Kaposi's Sarcoma-Associated Herpesvirus Lytic Replication

    PubMed Central

    Liang, Qiming; Chang, Brian; Lee, Patrick; Brulois, Kevin F.; Ge, Jianning; Shi, Mude; Rodgers, Mary A.; Feng, Pinghui; Oh, Byung-Ha; Liang, Chengyu

    2015-01-01

    ABSTRACT Kaposi's sarcoma-associated herpesvirus (KSHV) evades host defenses through tight suppression of autophagy by targeting each step of its signal transduction: by viral Bcl-2 (vBcl-2) in vesicle nucleation, by viral FLIP (vFLIP) in vesicle elongation, and by K7 in vesicle maturation. By exploring the roles of KSHV autophagy-modulating genes, we found, surprisingly, that vBcl-2 is essential for KSHV lytic replication, whereas vFLIP and K7 are dispensable. Knocking out vBcl-2 from the KSHV genome resulted in decreased lytic gene expression at the mRNA and protein levels, a lower viral DNA copy number, and, consequently, a dramatic reduction in the amount of progeny infectious viruses, as also described in the accompanying article (A. Gelgor, I. Kalt, S. Bergson, K. F. Brulois, J. U. Jung, and R. Sarid, J Virol 89:5298–5307, 2015). More importantly, the antiapoptotic and antiautophagic functions of vBcl-2 were not required for KSHV lytic replication. Using a comprehensive mutagenesis analysis, we identified that glutamic acid 14 (E14) of vBcl-2 is critical for KSHV lytic replication. Mutating E14 to alanine totally blocked KSHV lytic replication but showed little or no effect on the antiapoptotic and antiautophagic functions of vBcl-2. Our study indicates that vBcl-2 harbors at least three important and genetically separable functions to modulate both cellular signaling and the virus life cycle. IMPORTANCE The present study shows for the first time that vBcl-2 is essential for KSHV lytic replication. Removal of the vBcl-2 gene results in a lower level of KSHV lytic gene expression, impaired viral DNA replication, and consequently, a dramatic reduction in the level of progeny production. More importantly, the role of vBcl-2 in KSHV lytic replication is genetically separated from its antiapoptotic and antiautophagic functions, suggesting that the KSHV Bcl-2 carries a novel function in viral lytic replication. PMID:25740994

  17. A Kaposi's sarcoma-associated herpesvirus/human herpesvirus 8 ORF50 deletion mutant is defective for reactivation of latent virus and DNA replication.

    PubMed

    Xu, Yiyang; AuCoin, David P; Huete, Alicia Rodriguez; Cei, Sylvia A; Hanson, Lisa J; Pari, Gregory S

    2005-03-01

    Kaposi's sarcoma-associated herpesvirus (also called human herpesvirus type 8 [HHV8]) latently infects a number of cell types. Reactivation of latent virus can occur by treatment with the phorbol ester tetradecanoyl phorbol acetate (TPA) or with the transfection of plasmids expressing the lytic switch activator protein K-Rta, the gene product of ORF50. K-Rta expression is sufficient for the activation of the entire lytic cycle and the transactivation of viral genes necessary for DNA replication. In addition, recent evidence has suggested that K-Rta may participate directly in the initiation of lytic DNA synthesis. We have now generated a recombinant HHV8 bacterial artificial chromosome (BAC) with a large deletion within the ORF50 locus. This BAC, BAC36Delta50, failed to produce infectious virus upon treatment with TPA and was defective for DNA synthesis. Expression of K-Rta in trans in BAC36Delta50-containing cells was able to abolish both defects. Real-time PCR revealed that K-bZIP, ORF40/41, and K8.1 were not expressed when BAC36Delta50-containing cells were induced with TPA. However, the mRNA levels of ORF57 were over fivefold higher in TPA-treated BAC36Delta50-containing cells than those observed in similarly treated wild-type BAC-containing cells. In addition, immunohistochemical analysis showed that while the latency-associated nuclear antigen (LANA) was expressed in the mutant BAC-containing cells, ORF59 and K8.1 expression was not detected in TPA-induced BAC36Delta50-containing cells. These results showed that K-Rta is essential for lytic viral reactivation and transactivation of viral genes contributing to DNA replication.

  18. Epidemiology, pathophysiology and treatment of Kaposi sarcoma-associated herpesvirus disease: Kaposi sarcoma, primary effusion lymphoma, and multicentric Castleman disease

    PubMed Central

    Sullivan, Ryan J.; Pantanowitz, Liron; Casper, Corey; Stebbing, Justin; Dezube, Bruce J.

    2009-01-01

    KSHV infection is associated with the development of three proliferative diseases: Kaposi sarcoma (KS), primary effusion lymphoma (PEL), and multicentric Castleman disease (MCD). These conditions are also intimately associated with human immunodeficiency virus (HIV) infection, and important synergistic interactions between these two viruses have been described. Despite differences in viral gene expression patterns for each condition, KSHV encodes similar oncogenic proteins which promote the activation of sequential and parallel signaling pathways. Therapeutic strategies have been implemented to target these unique signaling pathways, and such molecular targeting is the focus of many current research efforts. The scope of this review is to present contemporary knowledge about the epidemiology, virology, and immunology of KSHV, as well as highlight several key oncogene products, which may be targets for chemotherapy. PMID:18808357

  19. Intracellular activated Notch1 is critical for proliferation of Kaposi's sarcoma-associated herpesvirus-associated B-lymphoma cell lines in vitro.

    PubMed

    Lan, Ke; Choudhuri, Tathagata; Murakami, Masanao; Kuppers, Daniel A; Robertson, Erle S

    2006-07-01

    Kaposi's sarcoma-associated herpesvirus (KSHV) is a human tumor virus expressing latent antigens critical for pathogenesis. The mechanism by which KSHV mediates oncogenesis has not been fully elucidated. Notch signaling is an evolutionarily conserved pathway controlling diverse events related to development, proliferation, and tissue homeostasis. Deregulation of Notch signaling has also been shown to be highly correlated with oncogenesis. Here we show that the activated intracellular domain of Notch1 (ICN) is aberrantly accumulated in latently KSHV-infected pleural effusion lymphoma cells and results in increased proliferation. Specifically, growth of the infected cells was dramatically inhibited at the G(1) phase by treatment with a gamma-secretase inhibitor which specifically blocks the production of ICN. Increased ICN also up-regulated the cyclin D1 cell cycle regulator. Taken together, these studies define an important mechanism directly linking latent KSHV infection to induction of oncogenesis through dysregulation of the conserved Notch signaling pathway.

  20. DNA-PK/Ku complex binds to latency-associated nuclear antigen and negatively regulates Kaposi's sarcoma-associated herpesvirus latent replication

    SciTech Connect

    Cha, Seho; Lim, Chunghun; Lee, Jae Young; Song, Yoon-Jae; Park, Junsoo; Choe, Joonho; Seo, Taegun

    2010-04-16

    During latent infection, latency-associated nuclear antigen (LANA) of Kaposi's sarcoma-associated herpesvirus (KSHV) plays important roles in episomal persistence and replication. Several host factors are associated with KSHV latent replication. Here, we show that the catalytic subunit of DNA protein kinase (DNA-PKcs), Ku70, and Ku86 bind the N-terminal region of LANA. LANA was phosphorylated by DNA-PK and overexpression of Ku70, but not Ku86, impaired transient replication. The efficiency of transient replication was significantly increased in the HCT116 (Ku86 +/-) cell line, compared to the HCT116 (Ku86 +/+) cell line, suggesting that the DNA-PK/Ku complex negatively regulates KSHV latent replication.

  1. Propranolol Decreases Proliferation of Endothelial Cells Transformed by Kaposi's Sarcoma-Associated Herpesvirus and Induces Lytic Viral Gene Expression

    PubMed Central

    Hanson, Ryan S.; Manion, Rory D.

    2015-01-01

    Kaposi's sarcoma (KS) is common in Africa, but economic constraints hinder successful treatment in most patients. Propranolol, a generic β-adrenergic antagonist, decreased proliferation of KS-associated herpesvirus (KSHV)-infected cells. Downregulation of cyclin A2 and cyclin-dependent kinase 1 (CDK1) recapitulated this phenotype. Additionally, propranolol induced lytic gene expression in association with downregulation of CDK6. Thus, propranolol has diverse effects on KSHV-infected cells, and this generic drug has potential as a therapeutic agent for KS. PMID:26269192

  2. Propranolol Decreases Proliferation of Endothelial Cells Transformed by Kaposi's Sarcoma-Associated Herpesvirus and Induces Lytic Viral Gene Expression.

    PubMed

    McAllister, Shane C; Hanson, Ryan S; Manion, Rory D

    2015-11-01

    Kaposi's sarcoma (KS) is common in Africa, but economic constraints hinder successful treatment in most patients. Propranolol, a generic β-adrenergic antagonist, decreased proliferation of KS-associated herpesvirus (KSHV)-infected cells. Downregulation of cyclin A2 and cyclin-dependent kinase 1 (CDK1) recapitulated this phenotype. Additionally, propranolol induced lytic gene expression in association with downregulation of CDK6. Thus, propranolol has diverse effects on KSHV-infected cells, and this generic drug has potential as a therapeutic agent for KS. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  3. X-Box Binding Protein 1 Contributes to Induction of the Kaposi's Sarcoma-Associated Herpesvirus Lytic Cycle under Hypoxic Conditions▿

    PubMed Central

    Dalton-Griffin, Lucy; Wilson, Sam J.; Kellam, Paul

    2009-01-01

    Kaposi's sarcoma-associated herpesvirus (KSHV), like other herpesviruses, has two stages to its life cycle: latency and lytic replication. KSHV is required for development of Kaposi's sarcoma, a tumor of endothelial origin, and is associated with the B-cell tumor primary effusion lymphoma (PEL) and the plasmablastic variant of multicentric Castleman's disease, all of which are characterized by predominantly latent KSHV infection. Recently, we and others have shown that the activated form of transcription factor X-box binding protein 1 (XBP-1) is a physiological trigger of KSHV lytic reactivation in PEL. Here, we show that XBP-1s transactivates the ORF50/RTA promoter though an ACGT core containing the XBP-1 response element, an element previously identified as a weakly active hypoxia response element (HRE). Hypoxia induces the KSHV lytic cycle, and active HREs that respond to hypoxia-inducible factor 1α are present in the ORF50/RTA promoter. Hypoxia also induces active XBP-1s, and here, we show that both transcription factors contribute to the induction of RTA expression, leading to the production of infectious KSHV under hypoxic conditions. PMID:19403667

  4. Selective killing of Kaposi's sarcoma-associated herpesvirus lytically infected cells with a recombinant immunotoxin targeting the viral gpK8.1A envelope glycoprotein

    PubMed Central

    Chatterjee, Deboeeta; Chandran, Bala

    2012-01-01

    Kaposi sarcoma-associated herpesvirus (KSHV, human herpesvirus 8) is etiologically associated with three neoplastic syndromes: Kaposi sarcoma and the uncommon HIV-associated B-cell lymphoproliferative disorders primary effusion lymphoma and multicentric Castleman disease. The incidence of the latter B-cell pathology has been increasing in spite of antiretroviral therapy; its association with lytic virus replication has prompted interest in therapeutic strategies aimed at this phase of the virus life cycle. We designed and expressed a recombinant immunotoxin (2014-PE38) targeting the gpK8.1A viral glycoprotein expressed on the surface of the virion and infected cells. We show that this immunotoxin selectively kills KSHV-infected cells in dose-dependent fashion, resulting in major reductions of infectious virus release. The immunotoxin and ganciclovir, an inhibitor of viral DNA replication, showed marked reciprocal potentiation of antiviral activities. These results suggest that the immunotoxin, alone or in combination, may represent a new approach to treat diseases associated with KSHV lytic replication. PMID:22377676

  5. Array-based transcript profiling and limiting-dilution reverse transcription-PCR analysis identify additional latent genes in Kaposi's sarcoma-associated herpesvirus.

    PubMed

    Chandriani, Sanjay; Ganem, Don

    2010-06-01

    Kaposi's sarcoma-associated herpesvirus (KSHV) is a B-lymphotropic herpesvirus strongly linked to both lymphoproliferative diseases and Kaposi's sarcoma. The viral latency program of KSHV is central to persistent infection and plays important roles in the pathogenesis of KSHV-related tumors. Up to six polypeptides and 18 microRNAs are known to be expressed in latency, but it is unclear if all major latency genes have been identified. Here, we have employed array-based transcript profiling and limiting-dilution reverse transcription-PCR (RT-PCR) methodologies to explore this issue in several KSHV-infected cell lines. Our results show that RNAs encoding the K1 protein are found at low levels in most latently infected cell lines. The gene encoding v-IL-6 is also expressed as a latent transcript in some contexts. Both genes encode powerful signaling molecules with particular relevance to B cell biology: K1 mimics signaling through the B cell receptor, and v-IL-6 promotes B cell survival. These data resolve earlier controversies about K1 and v-IL-6 expression and indicate that, in addition to core latency genes, some transcripts can be expressed in KSHV latency in a context-dependent manner.

  6. Generation of high-titre virus stocks using BrK.219, a B-cell line infected stably with recombinant Kaposi's sarcoma-associated herpesvirus.

    PubMed

    Kati, Semra; Hage, Elias; Mynarek, Martin; Ganzenmueller, Tina; Indenbirken, Daniela; Grundhoff, Adam; Schulz, Thomas F

    2015-06-01

    Kaposi's sarcoma-associated herpesvirus (KSHV) is a gamma-2-lymphotropic human oncogenic herpesvirus associated with Kaposi's sarcoma (KS) and two B-cell lymphoproliferative diseases, primary effusion lymphoma (PEL) and multicentric Castleman's disease (MCD). KSHV establishes latency soon after infection in vivo and in vitro. Consequently, it is technically difficult to generate high-titre virus stocks required for infection experiments in tissue culture. Currently used methods of KSHV stock production involve induction of the lytic/productive cycle in PEL cell lines or in adherent cell lines harbouring recombinant KSHV genomes. In this study, the BJAB-derived B-cell line BrK.219, which is infected latently with a recombinant KSHV (rKSHV.219), is used to produce high-titre virus stocks. BrK.219 cells enter the lytic KSHV replication cycle upon cross-linking of B-cell receptors (BCRs) with anti-IgM antibodies without the need for additional, potentially toxic chemical inducers. High cell concentrations can be cultured and induced easily in spinner flasks, saving time and resources. The established protocol allows the generation of KSHV virus stocks with titres of up to 10(6) IU/ml in unconcentrated culture supernatants, representing a 10(3)-10(4)-fold improvement compared to conventional methods.

  7. SIAH-1 interacts with the Kaposi's sarcoma-associated herpesvirus-encoded ORF45 protein and promotes its ubiquitylation and proteasomal degradation.

    PubMed

    Abada, Rinat; Dreyfuss-Grossman, Tsofia; Herman-Bachinsky, Yifat; Geva, Haim; Masa, Shiri-Rivka; Sarid, Ronit

    2008-03-01

    Kaposi's sarcoma-associated herpesvirus (KSHV), also referred to as human herpesvirus 8, is a potentially tumorigenic virus implicated in the etiology of Kaposi's sarcoma, primary effusion lymphoma, and some forms of multicentric Castleman's disease. The open reading frame 45 (ORF45) protein, encoded by the KSHV genome, is capable of inhibiting virus-dependent interferon induction and appears to be essential for both early and late stages of infection. In the present study, we show, both in yeast two-hybrid assays and in mammalian cells, that the ORF45 protein interacts with the cellular ubiquitin E3 ligase family designated seven in absentia homologue (SIAH). We provide evidence that SIAH-1 promotes the degradation of KSHV ORF45 through a RING domain-dependent mechanism and via the ubiquitin-proteasome system. Furthermore, our data indicate the involvement of SIAH-1 in the regulation of the expression of ORF45 in KSHV-infected cells. Since the availability of KSHV ORF45 is expected to influence the course of KSHV infection, our findings identify a novel biological role for SIAH proteins as modulators of virus infection.

  8. SIAH-1 Interacts with the Kaposi's Sarcoma-Associated Herpesvirus-Encoded ORF45 Protein and Promotes Its Ubiquitylation and Proteasomal Degradation▿

    PubMed Central

    Abada, Rinat; Dreyfuss-Grossman, Tsofia; Herman-Bachinsky, Yifat; Geva, Haim; Masa, Shiri-Rivka; Sarid, Ronit

    2008-01-01

    Kaposi's sarcoma-associated herpesvirus (KSHV), also referred to as human herpesvirus 8, is a potentially tumorigenic virus implicated in the etiology of Kaposi's sarcoma, primary effusion lymphoma, and some forms of multicentric Castleman's disease. The open reading frame 45 (ORF45) protein, encoded by the KSHV genome, is capable of inhibiting virus-dependent interferon induction and appears to be essential for both early and late stages of infection. In the present study, we show, both in yeast two-hybrid assays and in mammalian cells, that the ORF45 protein interacts with the cellular ubiquitin E3 ligase family designated seven in absentia homologue (SIAH). We provide evidence that SIAH-1 promotes the degradation of KSHV ORF45 through a RING domain-dependent mechanism and via the ubiquitin-proteasome system. Furthermore, our data indicate the involvement of SIAH-1 in the regulation of the expression of ORF45 in KSHV-infected cells. Since the availability of KSHV ORF45 is expected to influence the course of KSHV infection, our findings identify a novel biological role for SIAH proteins as modulators of virus infection. PMID:18077711

  9. The ubiquitin-specific protease USP7 modulates the replication of Kaposi's sarcoma-associated herpesvirus latent episomal DNA.

    PubMed

    Jäger, Wiebke; Santag, Susann; Weidner-Glunde, Magdalena; Gellermann, Eva; Kati, Semra; Pietrek, Marcel; Viejo-Borbolla, Abel; Schulz, Thomas F

    2012-06-01

    Kaposi's sarcoma herpesvirus (KSHV) belongs to the gamma-2 Herpesviridae and is associated with three neoplastic disorders: Kaposi's sarcoma (KS), primary effusion lymphoma (PEL), and multicentric Castleman's disease (MCD). The viral latency-associated nuclear antigen 1 (LANA) is expressed in all latently KSHV-infected cells and is involved in viral latent replication and maintenance of the viral genome. We show that LANA interacts with the ubiquitin-specific protease USP7 through its N-terminal TRAF (tumor necrosis factor [TNF] receptor-associated factor) domain. This interaction involves a short sequence (amino acids [aa] 971 to 986) within the C-terminal domain of LANA with strong similarities to the USP7 binding site of the Epstein-Barr virus (EBV) EBNA-1 protein. A LANA mutant with a deletion of the identified USP7 binding site showed an enhanced ability to replicate a plasmid containing the KSHV latent origin of replication but was comparable to the wild-type LANA (LANA WT) with regard to the regulation of viral and cellular promoters. Furthermore, the LANA homologues of two other gamma-2 herpesviruses, MHV68 and RRV, also recruit USP7. Our findings suggest that recruitment of USP7 to LANA could play a role in the regulation of viral latent replication. The recruitment of USP7, and its role in herpesvirus latent replication, previously described for the latent EBNA-1 protein of the gamma-1 herpesvirus (lymphocryptovirus) EBV (M. N. Holowaty et al., J. Biol. Chem. 278:29987-29994, 2003), may thereby be a conserved feature among gammaherpesvirus latent origin binding proteins.

  10. The Ubiquitin-Specific Protease USP7 Modulates the Replication of Kaposi's Sarcoma-Associated Herpesvirus Latent Episomal DNA

    PubMed Central

    Jäger, Wiebke; Santag, Susann; Weidner-Glunde, Magdalena; Gellermann, Eva; Kati, Semra; Pietrek, Marcel; Viejo-Borbolla, Abel

    2012-01-01

    Kaposi's sarcoma herpesvirus (KSHV) belongs to the gamma-2 Herpesviridae and is associated with three neoplastic disorders: Kaposi's sarcoma (KS), primary effusion lymphoma (PEL), and multicentric Castleman's disease (MCD). The viral latency-associated nuclear antigen 1 (LANA) is expressed in all latently KSHV-infected cells and is involved in viral latent replication and maintenance of the viral genome. We show that LANA interacts with the ubiquitin-specific protease USP7 through its N-terminal TRAF (tumor necrosis factor [TNF] receptor-associated factor) domain. This interaction involves a short sequence (amino acids [aa] 971 to 986) within the C-terminal domain of LANA with strong similarities to the USP7 binding site of the Epstein-Barr virus (EBV) EBNA-1 protein. A LANA mutant with a deletion of the identified USP7 binding site showed an enhanced ability to replicate a plasmid containing the KSHV latent origin of replication but was comparable to the wild-type LANA (LANA WT) with regard to the regulation of viral and cellular promoters. Furthermore, the LANA homologues of two other gamma-2 herpesviruses, MHV68 and RRV, also recruit USP7. Our findings suggest that recruitment of USP7 to LANA could play a role in the regulation of viral latent replication. The recruitment of USP7, and its role in herpesvirus latent replication, previously described for the latent EBNA-1 protein of the gamma-1 herpesvirus (lymphocryptovirus) EBV (M. N. Holowaty et al., J. Biol. Chem. 278:29987–29994, 2003), may thereby be a conserved feature among gammaherpesvirus latent origin binding proteins. PMID:22514345

  11. CTCF and Rad21 act as host cell restriction factors for Kaposi's sarcoma-associated herpesvirus (KSHV) lytic replication by modulating viral gene transcription.

    PubMed

    Li, Da-Jiang; Verma, Dinesh; Mosbruger, Tim; Swaminathan, Sankar

    2014-01-01

    Kaposi's sarcoma-associated herpesvirus (KSHV) is a human herpesvirus that causes Kaposi's sarcoma and is associated with the development of lymphoproliferative diseases. KSHV reactivation from latency and virion production is dependent on efficient transcription of over eighty lytic cycle genes and viral DNA replication. CTCF and cohesin, cellular proteins that cooperatively regulate gene expression and mediate long-range DNA interactions, have been shown to bind at specific sites in herpesvirus genomes. CTCF and cohesin regulate KSHV gene expression during latency and may also control lytic reactivation, although their role in lytic gene expression remains incompletely characterized. Here, we analyze the dynamic changes in CTCF and cohesin binding that occur during the process of KSHV viral reactivation and virion production by high resolution chromatin immunoprecipitation and deep sequencing (ChIP-Seq) and show that both proteins dissociate from viral genomes in kinetically and spatially distinct patterns. By utilizing siRNAs to specifically deplete CTCF and Rad21, a cohesin component, we demonstrate that both proteins are potent restriction factors for KSHV replication, with cohesin knockdown leading to hundred-fold increases in viral yield. High-throughput RNA sequencing was used to characterize the transcriptional effects of CTCF and cohesin depletion, and demonstrated that both proteins have complex and global effects on KSHV lytic transcription. Specifically, both proteins act as positive factors for viral transcription initially but subsequently inhibit KSHV lytic transcription, such that their net effect is to limit KSHV RNA accumulation. Cohesin is a more potent inhibitor of KSHV transcription than CTCF but both proteins are also required for efficient transcription of a subset of KSHV genes. These data reveal novel effects of CTCF and cohesin on transcription from a relatively small genome that resemble their effects on the cellular genome by acting as

  12. Kaposi's sarcoma-associated herpesvirus polyadenylated nuclear RNA: a structural scaffold for nuclear, cytoplasmic and viral proteins

    PubMed Central

    Rausch, Jason W.; Smith, Rodman; Miller, Jennifer T.; Whitby, Denise

    2017-01-01

    Abstract Kaposi's sarcoma-associated herpes virus (KSHV) polyadenylated nuclear (PAN) RNA facilitates lytic infection, modulating the cellular immune response by interacting with viral and cellular proteins and DNA. Although a number nucleoprotein interactions involving PAN have been implicated, our understanding of binding partners and PAN RNA binding motifs remains incomplete. Herein, we used SHAPE-mutational profiling (SHAPE-MaP) to probe PAN in its nuclear, cytoplasmic or viral environments or following cell/virion lysis and removal of proteins. We thus characterized and put into context discrete RNA structural elements, including the cis-acting Mta responsive element and expression and nuclear retention element (1,2). By comparing mutational profiles in different biological contexts, we identified sites on PAN either protected from chemical modification by protein binding or characterized by a loss of structure. While some protein binding sites were selectively localized, others were occupied in all three biological contexts. Individual binding sites of select KSHV gene products on PAN RNA were also identified in in vitro experiments. This work constitutes the most extensive structural characterization of a viral lncRNA and interactions with its protein partners in discrete biological contexts, providing a broad framework for understanding the roles of PAN RNA in KSHV infection. PMID:28383682

  13. Kaposi's sarcoma-associated herpesvirus polyadenylated nuclear RNA: a structural scaffold for nuclear, cytoplasmic and viral proteins.

    PubMed

    Sztuba-Solinska, Joanna; Rausch, Jason W; Smith, Rodman; Miller, Jennifer T; Whitby, Denise; Le Grice, Stuart F J

    2017-04-05

    Kaposi's sarcoma-associated herpes virus (KSHV) polyadenylated nuclear (PAN) RNA facilitates lytic infection, modulating the cellular immune response by interacting with viral and cellular proteins and DNA. Although a number nucleoprotein interactions involving PAN have been implicated, our understanding of binding partners and PAN RNA binding motifs remains incomplete. Herein, we used SHAPE-mutational profiling (SHAPE-MaP) to probe PAN in its nuclear, cytoplasmic or viral environments or following cell/virion lysis and removal of proteins. We thus characterized and put into context discrete RNA structural elements, including the cis-acting Mta responsive element and expression and nuclear retention element (1,2). By comparing mutational profiles in different biological contexts, we identified sites on PAN either protected from chemical modification by protein binding or characterized by a loss of structure. While some protein binding sites were selectively localized, others were occupied in all three biological contexts. Individual binding sites of select KSHV gene products on PAN RNA were also identified in in vitro experiments. This work constitutes the most extensive structural characterization of a viral lncRNA and interactions with its protein partners in discrete biological contexts, providing a broad framework for understanding the roles of PAN RNA in KSHV infection.

  14. SIRT1-mediated downregulation of p27Kip1 is essential for overcoming contact inhibition of Kaposi's sarcoma-associated herpesvirus transformed cells.

    PubMed

    He, Meilan; Yuan, Hongfeng; Tan, Brandon; Bai, Rosemary; Kim, Heon Seok; Bae, Sangsu; Che, Lu; Kim, Jin-Soo; Gao, Shou-Jiang

    2016-11-15

    Kaposi's sarcoma-associated herpesvirus (KSHV) is an oncogenic virus associated with Kaposi's sarcoma (KS), a malignancy commonly found in AIDS patients. Despite intensive studies in the last two decades, the mechanism of KSHV-induced cellular transformation and tumorigenesis remains unclear. In this study, we found that the expression of SIRT1, a metabolic sensor, was upregulated in a variety of KSHV-infected cells. In a model of KSHV-induced cellular transformation, SIRT1 knockdown with shRNAs or knockout by CRISPR/Cas9 gene editing dramatically suppressed cell proliferation and colony formation in soft agar of KSHV-transformed cells by inducing cell cycle arrest and contact inhibition. SIRT1 knockdown or knockout induced the expression of cyclin-dependent kinase inhibitor 1B (p27Kip1). Consequently, p27 knockdown rescued the inhibitory effect of SIRT1 knockdown or knockout on cell proliferation and colony formation. Furthermore, treatment of KSHV-transformed cells with a SIRT1 inhibitor, nicotinamide (NAM), had the same effect as SIRT1 knockdown and knockout. NAM significantly inhibited cell proliferation in culture and colony formation in soft agar, and induced cell cycle arrest. Significantly, NAM inhibited the progression of tumors and extended the survival of mice in a KSHV-induced tumor model. Collectively, these results demonstrate that SIRT1 suppression of p27 is required for KSHV-induced tumorigenesis and identify a potential therapeutic target for KS.

  15. Inhibition of replication and transcription activator and latency-associated nuclear antigen of Kaposi's sarcoma-associated herpesvirus by morpholino oligomers.

    PubMed

    Zhang, Yan-Jin; Wang, Kai-Yu; Stein, David A; Patel, Deendayal; Watkins, Rheba; Moulton, Hong M; Iversen, Patrick L; Matson, David O

    2007-01-01

    Kaposi's sarcoma-associated herpesvirus (KSHV) is associated with Kaposi's sarcoma and primary effusion lymphoma (PEL). The KSHV replication and transcription activator (RTA) and latency-associated nuclear antigen (LANA) play key roles in activating KSHV lytic replication and maintaining KSHV latency, respectively. Phosphorodiamidate morpholino oligomers (PMO) are similar to short single-stranded DNA oligomers, but possess a modified backbone that confers highly specific binding and resistance to nucleases. In this study, RTA and LANA mRNA in PEL cells were targeted by antisense peptide-conjugated PMO (P-PMO) in an effort to suppress KSHV replication. Highly efficient P-PMO uptake by PEL cells was observed. Treatment of PEL cells with a RTA P-PMO (RP1) reduced RTA expression in a dose-dependent and sequence-specific manner, and also caused a significant decrease in several KSHV early and late gene products, including vIL-6, vIRF-1, and ORF-K8.1A. KSHV viral DNA levels were reduced both in cells and culture supernatants of RP1 P-PMO-treated cells, indicating that KSHV lytic replication was suppressed. Treatment of BCBL-1 cells with P-PMO against LANA resulted in a reduction of LANA expression. Cell viability assays detected no cytotoxicity from P-PMO alone, within the concentration range used for the experiments in this study. These results suggest that RP1 P-PMO can specifically block KSHV replication, and further study is warranted.

  16. NEDDylation is essential for Kaposi's sarcoma-associated herpesvirus latency and lytic reactivation and represents a novel anti-KSHV target.

    PubMed

    Hughes, David J; Wood, Jennifer J; Jackson, Brian R; Baquero-Pérez, Belinda; Whitehouse, Adrian

    2015-03-01

    Kaposi's sarcoma-associated herpesvirus (KSHV) is the causative agent of Kaposi's sarcoma (KS) and primary effusion lymphoma (PEL), which are aggressive malignancies associated with immunocompromised patients. For many non-viral malignancies, therapeutically targeting the ubiquitin proteasome system (UPS) has been successful. Likewise, laboratory studies have demonstrated that inhibition of the UPS might provide a promising avenue for the treatment of KSHV-associated diseases. The largest class of E3 ubiquitin ligases are the cullin-RING ligases (CRLs) that are activated by an additional ubiquitin-like protein, NEDD8. We show that pharmacological inhibition of NEDDylation (using the small molecule inhibitor MLN4924) is cytotoxic to PEL cells by inhibiting NF-κB. We also show that CRL4B is a novel regulator of latency as its inhibition reactivated lytic gene expression. Furthermore, we uncovered a requirement for NEDDylation during the reactivation of the KSHV lytic cycle. Intriguingly, inhibition prevented viral DNA replication but not lytic cycle-associated gene expression, highlighting a novel mechanism that uncouples these two features of KSHV biology. Mechanistically, we show that MLN4924 treatment precluded the recruitment of the viral pre-replication complex to the origin of lytic DNA replication (OriLyt). These new findings have revealed novel mechanisms that regulate KSHV latency and reactivation. Moreover, they demonstrate that inhibition of NEDDylation represents a novel approach for the treatment of KSHV-associated malignancies.

  17. High incidence of Kaposi sarcoma-associated herpesvirus infection in HIV-related solid immunoblastic/plasmablastic diffuse large B-cell lymphoma.

    PubMed

    Deloose, S T P; Smit, L A; Pals, F T; Kersten, M-J; van Noesel, C J M; Pals, S T

    2005-05-01

    Kaposi sarcoma-associated herpesvirus (KSHV) is known to be associated with two distinct lymphoproliferative disorders: primary effusion lymphoma (PEL) and multicentric Castleman disease (MCD)/MCD-associated plasmablastic lymphoma. We here report a high incidence of KSHV infection in solid HIV-associated immunoblastic/plasmablastic non-Hodgkin's lymphomas (NHLs), in patients lacking effusions and without evidence of (prior) MCD. Within a cohort of 99 HIV-related NHLs, 10 cases were found to be KSHV positive on the basis of immunostaining for KSHV LNA-1 as well as KSHV-specific polymerase chain reaction. All but one of the tumors coexpressed Epstein-Barr virus. Interestingly, all KSHV-positive cases belonged to a distinctive subgroup of 26 diffuse large B-cell lymphomas characterized by the expression of CD138 (syndecan-1) and plasmablastic/immunoblastic morphology. These KSHV-positive lymphomas were preceded by Kaposi sarcoma in 60% of the patients and involved the gastrointestinal tract in 80%. Our results indicate that KSHV infection is not restricted to PEL and MCD; it is also common (38%) in HIV-related solid immunoblastic/plasmablastic lymphomas.

  18. Induction of Kaposi's sarcoma-associated herpesvirus latency-associated nuclear antigen by the lytic transactivator RTA: a novel mechanism for establishment of latency.

    PubMed

    Lan, Ke; Kuppers, Daniel A; Verma, Subhash C; Sharma, Nikhil; Murakami, Masanao; Robertson, Erle S

    2005-06-01

    Kaposi's sarcoma-associated herpesvirus (KSHV) is the etiological agent contributing to development of Kaposi's sarcoma, primary effusion lymphoma, and multicentric Castleman desease. Following primary infection, latency is typically established. However, the mechanism by which KSHV establishes latency is not understood. We have reported that the latency-associated nuclear antigen (LANA) can repress RTA (for replication and transcription activator) expression by down-regulating its promoter. In this study, we show that RTA is associated with the virion particle. We also show that RTA can activate the LANA promoter and induce LANA expression in transient reporter assays. Additionally, the transcription of RTA correlates with LANA expression in the early stages of de novo infection of KSHV, and induction of LANA transcription is responsive to induction of RTA with an inducible system. This induction in LANA transcription was dependent on recombination signal sequence binding protein Jkappa (RBP-Jkappa), as a RBP-Jkappa-deficient cell line was significantly delayed and inefficient in LANA transcription with expression of RTA. These studies suggest that RTA contributes to establishment of KSHV latency by activating LANA expression in the early stages of infection by utilizing the major effector of the Notch signaling pathway RBP-Jkappa. This describes a feedback mechanism by which LANA and RTA can regulate each other and is likely to be a key event in the establishment of KSHV latency.

  19. Induction of Kaposi's Sarcoma-Associated Herpesvirus Latency-Associated Nuclear Antigen by the Lytic Transactivator RTA: a Novel Mechanism for Establishment of Latency

    PubMed Central

    Lan, Ke; Kuppers, Daniel A.; Verma, Subhash C.; Sharma, Nikhil; Murakami, Masanao; Robertson, Erle S.

    2005-01-01

    Kaposi's sarcoma-associated herpesvirus (KSHV) is the etiological agent contributing to development of Kaposi's sarcoma, primary effusion lymphoma, and multicentric Castleman desease. Following primary infection, latency is typically established. However, the mechanism by which KSHV establishes latency is not understood. We have reported that the latency-associated nuclear antigen (LANA) can repress RTA (for replication and transcription activator) expression by down-regulating its promoter. In this study, we show that RTA is associated with the virion particle. We also show that RTA can activate the LANA promoter and induce LANA expression in transient reporter assays. Additionally, the transcription of RTA correlates with LANA expression in the early stages of de novo infection of KSHV, and induction of LANA transcription is responsive to induction of RTA with an inducible system. This induction in LANA transcription was dependent on recombination signal sequence binding protein Jκ (RBP-Jκ), as a RBP-Jκ-deficient cell line was significantly delayed and inefficient in LANA transcription with expression of RTA. These studies suggest that RTA contributes to establishment of KSHV latency by activating LANA expression in the early stages of infection by utilizing the major effector of the Notch signaling pathway RBP-Jκ. This describes a feedback mechanism by which LANA and RTA can regulate each other and is likely to be a key event in the establishment of KSHV latency. PMID:15919901

  20. Kaposi's sarcoma-associated herpesvirus viral IFN regulatory factor 3 stabilizes hypoxia-inducible factor-1 alpha to induce vascular endothelial growth factor expression.

    PubMed

    Shin, Young C; Joo, Chul-Hyun; Gack, Michaela U; Lee, Hye-Ra; Jung, Jae U

    2008-03-15

    Kaposi's sarcoma-associated herpesvirus (KSHV) is the etiologic agent associated with Kaposi's sarcoma, primary effusion lymphoma, and multicentric Castleman's disease. Hypoxia-inducible factor-1 (HIF-1) is the master regulator of both developmental and pathologic angiogenesis, composed of an oxygen-sensitive alpha-subunit and a constitutively expressed beta-subunit. HIF-1 activity in tumors depends on the availability of the HIF-1 alpha subunit, the levels of which are increased under hypoxic conditions. Recent studies have shown that HIF-1 plays an important role in KSHV reactivation from latency and pathogenesis. Here, we report a novel mechanism by which KSHV activates HIF-1 activity. Specific interaction between KSHV viral IFN regulatory factor 3 (vIRF3) and the HIF-1 alpha subunit led to the HIF-1 alpha stabilization and transcriptional activation, which induced vascular endothelial growth factor expression and ultimately facilitated endothelial tube formation. Remarkably, the central domain of vIRF3, containing double alpha-helix motifs, was sufficient not only for binding to HIF-1 alpha but also for blocking its degradation in normoxic conditions. This indicates that KSHV has developed a unique mechanism to enhance HIF-1 alpha protein stability and transcriptional activity by incorporating a viral homologue of cellular IRF gene into its genome, which may contribute to viral pathogenesis.

  1. Suppression of lytic replication of Kaposi's sarcoma-associated herpesvirus by autophagy during initial infection in NIH 3T3 fibroblasts.

    PubMed

    Jang, Gun-Hee; Lee, Jihui; Kim, Na-Yeon; Kim, Jae-Hyeon; Yeh, Jung-Yong; Han, Minsub; Ahn, Soon Kil; Kang, Hara; Lee, Michael

    2016-03-01

    Kaposi's sarcoma-associated herpesvirus (KSHV) is the infectious cause of the angioproliferative neoplasm Kaposi's sarcoma (KS). We first confirmed the susceptibility of NIH 3T3 fibroblasts to KSHV by infecting them with BCP-1-derived KSHV. Lytic replication of KSHV was confirmed by PCR amplification of viral DNA isolated from culture supernatants of KSHV-infected cells. The template from KSHV-infected NIH 3T3 cells resulted in an intense viral DNA PCR product. A time course experiment revealed the disappearance of KSHV-specific DNA in culture supernatant of NIH 3T3 cells during a period between 48 h and 72 h postinfection. Furthermore, 3 days postinfection, infected NIH 3T3 cells showed no evidence of latent or lytic transcripts, including LANA, vFLIP, vCyclin, and vIL-6. These results imply that KSHV infection in NIH 3T3 cells is unstable and is rapidly lost on subsequent culturing. Additionally, we detected an enhancement of autophagy early in infection with KSHV. More interestingly, inhibition of autophagy by Beclin 1 siRNA or 3-methyladenine significantly increased the amount of KSHV-specific DNA in the culture supernatant of NIH 3T3 cells when compared to the group treated with KSHV infection alone, implying that autophagy prevents lytic replication of KSHV. Taken together, our data suggest that autophagy could be one of the cellular mechanisms utilized by host cells to promote viral clearance.

  2. SIRT1-mediated downregulation of p27Kip1 is essential for overcoming contact inhibition of Kaposi's sarcoma-associated herpesvirus transformed cells

    PubMed Central

    Tan, Brandon; Bai, Rosemary; Kim, Heon Seok; Bae, Sangsu; Che, Lu; Kim, Jin-Soo; Gao, Shou-Jiang

    2016-01-01

    Kaposi's sarcoma-associated herpesvirus (KSHV) is an oncogenic virus associated with Kaposi's sarcoma (KS), a malignancy commonly found in AIDS patients. Despite intensive studies in the last two decades, the mechanism of KSHV-induced cellular transformation and tumorigenesis remains unclear. In this study, we found that the expression of SIRT1, a metabolic sensor, was upregulated in a variety of KSHV-infected cells. In a model of KSHV-induced cellular transformation, SIRT1 knockdown with shRNAs or knockout by CRISPR/Cas9 gene editing dramatically suppressed cell proliferation and colony formation in soft agar of KSHV-transformed cells by inducing cell cycle arrest and contact inhibition. SIRT1 knockdown or knockout induced the expression of cyclin-dependent kinase inhibitor 1B (p27Kip1). Consequently, p27 knockdown rescued the inhibitory effect of SIRT1 knockdown or knockout on cell proliferation and colony formation. Furthermore, treatment of KSHV-transformed cells with a SIRT1 inhibitor, nicotinamide (NAM), had the same effect as SIRT1 knockdown and knockout. NAM significantly inhibited cell proliferation in culture and colony formation in soft agar, and induced cell cycle arrest. Significantly, NAM inhibited the progression of tumors and extended the survival of mice in a KSHV-induced tumor model. Collectively, these results demonstrate that SIRT1 suppression of p27 is required for KSHV-induced tumorigenesis and identify a potential therapeutic target for KS. PMID:27708228

  3. Kaposi's Sarcoma-Associated Herpesvirus-Encoded LANA Down-Regulates IL-22R1 Expression through a Cis-Acting Element within the Promoter Region

    PubMed Central

    Su, Ling; Liao, Qingjiao; Wu, Yang; Chen, Xulin

    2011-01-01

    Kaposi's sarcoma-associated herpesvirus (KSHV) is considered to be a necessary, but not sufficient, causal agent of Kaposi's sarcoma (KS). All forms of KS are characterized by the proliferation of spindle-shaped cells, and most (>90%) spindle cells from KS lesions are latently infected with KSHV. During KSHV latency, only a few viral genes are expressed. Among those latent genes, the ORF 73 gene encodes the latency-associated nuclear antigen (LANA), which is critical for the establishment and maintenance of the latent KSHV infection. Much evidence suggests that many cytokines can increase the frequency and aggressiveness of KS. In this study, a microarray analysis of KS and normal tissues revealed that multiple cytokines and cytokine receptors are regulated by KSHV latent infection. Of special interest, IL-22R1 transcript level was found to be down-regulated in the KS tissue. To study the possible regulation of IL-22R1 by LANA, the IL-22R1 promoter was constructed and found to contain a LANA-binding site (LBS). LANA was demonstrated to down-regulate IL-22R1 expression via direct binding to the LBS located within the IL-22R1 promoter region. Furthermore, KSHV latently infected cells showed an impaired response to IL-22 stimulation. These results suggest that LANA can regulate host factor expression by directly binding to a cis-acting element within the factor's promoter to benefit latent viral infection and suppression of the antiviral immune response. PMID:21544244

  4. KSHV 2.0: a comprehensive annotation of the Kaposi's sarcoma-associated herpesvirus genome using next-generation sequencing reveals novel genomic and functional features.

    PubMed

    Arias, Carolina; Weisburd, Ben; Stern-Ginossar, Noam; Mercier, Alexandre; Madrid, Alexis S; Bellare, Priya; Holdorf, Meghan; Weissman, Jonathan S; Ganem, Don

    2014-01-01

    Productive herpesvirus infection requires a profound, time-controlled remodeling of the viral transcriptome and proteome. To gain insights into the genomic architecture and gene expression control in Kaposi's sarcoma-associated herpesvirus (KSHV), we performed a systematic genome-wide survey of viral transcriptional and translational activity throughout the lytic cycle. Using mRNA-sequencing and ribosome profiling, we found that transcripts encoding lytic genes are promptly bound by ribosomes upon lytic reactivation, suggesting their regulation is mainly transcriptional. Our approach also uncovered new genomic features such as ribosome occupancy of viral non-coding RNAs, numerous upstream and small open reading frames (ORFs), and unusual strategies to expand the virus coding repertoire that include alternative splicing, dynamic viral mRNA editing, and the use of alternative translation initiation codons. Furthermore, we provide a refined and expanded annotation of transcription start sites, polyadenylation sites, splice junctions, and initiation/termination codons of known and new viral features in the KSHV genomic space which we have termed KSHV 2.0. Our results represent a comprehensive genome-scale image of gene regulation during lytic KSHV infection that substantially expands our understanding of the genomic architecture and coding capacity of the virus.

  5. Protein kinase CK2 phosphorylation regulates the interaction of Kaposi's sarcoma-associated herpesvirus regulatory protein ORF57 with its multifunctional partner hnRNP K

    PubMed Central

    Malik, Poonam; Clements, J. Barklie

    2004-01-01

    ORF57 protein of Kaposi's sarcoma-associated herpesvirus has a counterpart in all herpesvirus of mammals and birds and regulates gene expression at transcriptional and post-transcriptional levels. ORF57 was capable of self-interaction and bound a rapidly migrating form of heterogeneous nuclear ribonucleoprotein K (hnRNP K), a multifunctional cellular protein involved in gene expression. In virus infected cell extracts, ORF57 was present in a complex with hnRNP K that had protein kinase CK2 activity, and was phosphorylated by CK2. Different regions of ORF57 bound both catalytic α/α′ and regulatory β subunits of CK2. CK2 modification enhanced the ORF57–hnRNP K interaction, and may regulate the presence and activities of components in the complex. We suggest that ORF57 and hnRNP K interaction may modulate ORF57-mediated regulation of viral gene expression. Herpesviral ORF57 (Rhadinovirus) and ICP27 (Simplexvirus) proteins both interact with hnRNP K and CK2 implying that adaptation of the ancestral hnRNP K and CK2 to associate with viral regulatory ancestor protein likely pre-dates divergence of these Herpesviridae genera that occurred 200 million years ago. PMID:15486205

  6. DNA binding by Kaposi's sarcoma-associated herpesvirus lytic switch protein is necessary for transcriptional activation of two viral delayed early promoters.

    PubMed

    Lukac, D M; Garibyan, L; Kirshner, J R; Palmeri, D; Ganem, D

    2001-08-01

    Kaposi's sarcoma-associated herpesvirus (KSHV; also known as human herpesvirus-8) establishes latent and lytic infections in both lymphoid and endothelial cells and has been associated with diseases of both cell types. The KSHV open reading frame 50 (ORF50) protein is a transcriptional activator that plays a central role in the reactivation of lytic viral replication from latency. Here we identify and characterize a DNA binding site for the ORF50 protein that is shared by the promoters of two delayed early genes (ORF57 and K-bZIP). Transfer of this element to heterologous promoters confers on them high-level responsiveness to ORF50, indicating that the element is both necessary and sufficient for activation. The element consists of a conserved 12-bp palindromic sequence and less conserved sequences immediately 3' to it. Mutational analysis reveals that sequences within the palindrome are critical for binding and activation by ORF50, but the presence of a palindrome itself is not absolutely required. The 3' flanking sequences also play a critical role in DNA binding and transactivation. The strong concordance of DNA binding in vitro with transcriptional activation in vivo strongly implies that sequence-specific DNA binding is necessary for ORF50-mediated activation through this element. Expression of truncated versions of the ORF50 protein reveals that DNA binding is mediated by the amino-terminal 272 amino acids of the polypeptide.

  7. The Kaposi's Sarcoma-Associated Herpesvirus ORF34 Protein Binds to HIF-1α and Causes Its Degradation via the Proteasome Pathway

    PubMed Central

    Kousoulas, Konstantin G.

    2013-01-01

    Kaposi's sarcoma-associated herpesvirus (KSHV) is the causative agent for Kaposi's sarcoma (KS) and two other lymphoproliferative disorders, primary effusion lymphoma (PEL) and multicentric Castleman's disease (MCD). Kaposi's sarcoma is a highly vascular tumor, and recently both hypoxia-inducible factor 1α (HIF-1α) and HIF-2α were detected in KS samples, indicating a role of HIFs in the KSHV life cycle. Previously, we showed that ORF34, a lytic gene of unassigned function, was activated by hypoxia and that ORF34 transcription was upregulated by both HIFs (M. Haque, D. A. Davis, V. Wang, I. Widmer, and R. Yarchoan, J Virol. 77:6761–6768, 2003). In the present study, we show that coexpression of ORF34 with HIF-1αm (degradation-resistant HIF-1α) caused substantial reduction in HIF-1α-dependent transcription, as evidenced by reporter assays. Two-way immunoprecipitation experiments revealed that ORF34 physically interacted with HIF-1αm in transient expression experiments. Deletion analysis revealed that three different ORF34 domains interacted with the amino-terminal domain of HIF-1α. Also, purified HIF-1α and ORF34 proteins interacted with each other. The observed transcriptional inhibition of HIF-1α-dependent promoters was attributed to degradation of HIF-1α after binding with ORF34, since the overall amount of wild-type HIF-1α but not the degradation-resistant one (HIF-1αm) was reduced in the presence of ORF34. Moreover, ORF34 caused degradation of HIF-1α in a dose-dependent manner. Inhibition of the ubiquitin-dependent pathway by the chemical proteasome inhibitor MG132 prevented HIF-1α degradation in the presence of ORF34. These results show that ORF34 binds to HIF-1α, leading to its degradation via the proteasome-dependent pathway. PMID:23221556

  8. Latency-associated nuclear antigen of Kaposi's sarcoma-associated herpesvirus (KSHV) upregulates survivin expression in KSHV-Associated B-lymphoma cells and contributes to their proliferation.

    PubMed

    Lu, Jie; Verma, Subhash C; Murakami, Masanao; Cai, Qiliang; Kumar, Pankaj; Xiao, Bingyi; Robertson, Erle S

    2009-07-01

    Survivin is a master regulator of cell proliferation and cell viability and is highly expressed in most human tumors. The molecular network linked to survivin expression in tumors has not been completely elucidated. In this study, we show that latency-associated nuclear antigen (LANA), a multifunctional protein of Kaposi's sarcoma-associated herpesvirus (KSHV) that is found in Kaposi's sarcoma tumors, upregulates survivin expression and increases the proliferation of KSHV-infected B cells. Analysis of pathway-specific gene arrays showed that survivin expression was highly upregulated in BJAB cells expressing LANA. The mRNA levels of survivin were also upregulated in HEK 293 and BJAB cells expressing LANA. Similarly, protein levels of survivin were significantly higher in LANA-expressing, as well as KSHV-infected, cells. Survivin promoter activity assays identified GC/Sp1 and p53 cis-acting elements within the core promoter region as being important for LANA activity. Gel mobility shift assays revealed that LANA forms a complex with Sp1 or Sp1-like proteins bound to the GC/Sp1 box of the survivin promoter. In addition, a LANA/p53 complex bound to the p53 cis-acting element within the survivin promoter, indicating that upregulation of survivin expression can also occur through suppression of p53 function. Furthermore, immunohistochemistry analyses revealed that survivin expression was upregulated in KSHV-associated Kaposi's sarcoma tissue, suggesting that LANA plays an important role in the upregulation of survivin expression in KSHV-infected endothelial cells. Knockdown of survivin expression by lentivirus-delivered small hairpin RNA resulted in loss of cell proliferation in KSHV-infected cells. Therefore, upregulation of survivin expression in KSHV-associated human cells contributes to their proliferation.

  9. Murine Gammaherpesvirus 68 Expressing Kaposi Sarcoma-Associated Herpesvirus Latency-Associated Nuclear Antigen (LANA) Reveals both Functional Conservation and Divergence in LANA Homologs.

    PubMed

    Gupta, Arundhati; Oldenburg, Darby G; Salinas, Eduardo; White, Douglas W; Forrest, J Craig

    2017-10-01

    Latency-associated nuclear antigen (LANA) is a multifunctional protein encoded by members of the Rhadinovirus genus of gammaherpesviruses. Studies using murine gammaherpesvirus 68 (MHV68) demonstrated that LANA is important for acute replication, latency establishment, and reactivation in vivo Despite structural similarities in their DNA-binding domains (DBDs), LANA homologs from Kaposi sarcoma-associated herpesvirus (KSHV) and MHV68 exhibit considerable sequence divergence. We sought to determine if KSHV and MHV68 LANA homologs are functionally interchangeable. We generated an MHV68 virus that encodes KSHV LANA (kLANA) in place of MHV68 LANA (mLANA) and evaluated the virus's capacity to replicate, establish and maintain latency, and reactivate. kLANA knock-in (KLKI) MHV68 was replication competent in vitro and in vivo but exhibited slower growth kinetics and lower titers than wild-type (WT) MHV68. Following inoculation of mice, KLKI MHV68 established and maintained latency in splenocytes and peritoneal cells but did not reactivate efficiently ex vivo kLANA repressed the MHV68 promoter for ORF50, the gene that encodes the major lytic transactivator protein RTA, while mLANA did not, suggesting a likely mechanism for the KLKI MHV68 phenotypes. Bypassing this repression by providing MHV68 RTA in trans rescued KLKI MHV68 replication in tissue culture and enabled detection of KLKI MHV68 reactivation ex vivo These data demonstrate that kLANA and mLANA are functionally interchangeable for establishment and maintenance of latency and suggest that repression of lytic replication by kLANA, as previously shown with KSHV, is a kLANA-specific function that is transferable to MHV68.IMPORTANCE Kaposi sarcoma-associated herpesvirus (KSHV) and murine gammaherpesvirus 68 (MHV68) are members of the Rhadinovirus genus of gammaherpesviruses. These viruses establish lifelong infections that place their respective human and murine hosts at risk for cancer. Latency-associated nuclear

  10. Major Histocompatibility Complex Class II HLA-DRα Is Downregulated by Kaposi's Sarcoma-Associated Herpesvirus-Encoded Lytic Transactivator RTA and MARCH8

    PubMed Central

    Sun, Zhiguo; Jha, Hem Chandra; Pei, Yong-gang

    2016-01-01

    ABSTRACT Kaposi's sarcoma-associated herpesvirus (KSHV) maintains two modes of life cycle, the latent and lytic phases. To evade the attack of the cell host's immune system, KSHV switches from the lytic to the latent phase, a phase in which only a few of viral proteins are expressed. The mechanism by which KSHV evades the attack of the immune system and establishes latency has not been fully understood. Major histocompatibility complex class II (MHC-II) molecules are key components of the immune system defense mechanism against viral infections. Here we report that HLA-DRα, a member of the MHC-II molecules, was downregulated by the replication and transcription activator (RTA) protein encoded by KSHV ORF50, an important regulator of the viral life cycle. RTA not only downregulated HLA-DRα at the protein level through direct binding and degradation through the proteasome pathway but also indirectly downregulated the protein level of HLA-DRα by enhancing the expression of MARCH8, a member of the membrane-associated RING-CH (MARCH) proteins. Our findings indicate that KSHV RTA facilitates evasion of the virus from the immune system through manipulation of HLA-DRα. IMPORTANCE Kaposi's sarcoma-associated herpesvirus (KSHV) has a causal role in a number of human cancers, and its persistence in infected cells is controlled by the host's immune system. The mechanism by which KSHV evades an attack by the immune system has not been well understood. This work represents studies which identify a novel mechanism by which the virus can facilitate evasion of an immune system. We now show that RTA, the replication and transcription activator encoded by KSHV (ORF50), can function as an E3 ligase to degrade HLA-DRα. It can directly bind and induce degradation of HLA-DRα through the ubiquitin-proteasome degradation pathway. In addition to the direct regulation of HLA-DRα, RTA can also indirectly downregulate the level of HLA-DRα protein by upregulating transcription of MARCH8

  11. Kaposi's-sarcoma-associated-herpesvirus-activated dendritic cells promote HIV-1 trans-infection and suppress CD4{sup +} T cell proliferation

    SciTech Connect

    Liu, Wan; Qin, Yan; Bai, Lei; Lan, Ke; Wang, Jian-Hua

    2013-06-05

    Infection of Kaposi's sarcoma-associated herpesvirus (KSHV) is commonly occurred in AIDS patients. KSHV and HIV-1 act cooperatively in regulating infection with each other and in human carcinogenesis. Dendritic cells (DCs), as the pivotal cells in host immunity, may be modulated by both viruses, for immunoevasion and dissemination, therefore, the interaction between DCs and each virus has been a prior focus for pathogenesis elucidation. Here, we assessed the potential effect of KSHV on DC–HIV-1 interaction. We found that KSHV stimulation could promote maturation of monocyte-derived DCs (MDDCs) and impaired the ability of MDDCs to drive proliferation of resting CD4{sup +} T cells, demonstrating the immunosuppression induced by KSHV. More importantly, KSHV-stimulated MDDCs could capture more HIV-1 and efficiently transferred these infectious viruses to Hut/CCR5 T cell line. Our results reveal the novel modulation of DC-mediated HIV-1 dissemination by KSHV, and highlight the importance of studying DC–HIV-1 interaction to elucidate HIV/AIDS pathogenesis. - Highlights: ► KSHV impaired the ability of MDDCs to drive proliferation of resting CD4{sup +} T cells. ► KSHV stimulation matured MDDCs and enhanced HIV-1 endocytosis. ► KSHV stimulated MDDCs increased ICAM-1 expression and tighten contact with T cells. ► KSHV-stimulated MDDCs promoted HIV-1 trans-infection of CD4{sup +} T cells.

  12. Kaposi's Sarcoma-associated herpesvirus lytic switch protein stimulates DNA binding of RBP-Jk/CSL to activate the Notch pathway.

    PubMed

    Carroll, Kyla Driscoll; Bu, Wei; Palmeri, Diana; Spadavecchia, Sophia; Lynch, Stephen J; Marras, Salvatore A E; Tyagi, Sanjay; Lukac, David M

    2006-10-01

    Kaposi's sarcoma-associated herpesvirus (KSHV) lytic switch protein, Rta, is a ligand-independent inducer of the Notch signal transduction pathway, and KSHV cannot reactivate from latency in cells null for the Notch target protein RBP-Jk. Here we show that Rta promotes DNA binding of RBP-Jk, a mechanism that is fundamentally different from that established for the RBP-Jk-activating proteins, Notch intracellular domain (NICD) and Epstein-Barr virus EBNA2. Although constitutively active RBP-Jk and NICD do not transactivate KSHV promoters independently, cotransfection of an Rta mutant lacking its transactivation domain robustly restores transcriptional activation. Cooperation requires intact DNA binding sites for Rta and RBP-Jk and trimeric complex formation between the three molecules in vitro. In infected cells, RBP-Jk is virtually undetectable on a series of viral and cellular promoters during KSHV latency but is significantly enriched following Rta expression during viral reactivation. Accordingly, Rta, but not EBNA2 and NICD, reactivates the complete viral lytic cycle.

  13. Kaposi's Sarcoma-Associated Herpesvirus Open Reading Frame 50/Rta Protein Activates the Entire Viral Lytic Cycle in the HH-B2 Primary Effusion Lymphoma Cell Line†

    PubMed Central

    Gradoville, Lyndle; Gerlach, Jennifer; Grogan, Elizabeth; Shedd, Duane; Nikiforow, Sarah; Metroka, Craig; Miller, George

    2000-01-01

    Rta, the gene product of Kaposi's sarcoma-associated herpesvirus (KSHV) encoded mainly in open reading frame 50 (ORF50), is capable of activating expression of viral lytic cycle genes. What was not demonstrated in previous studies was whether KSHV Rta was competent to initiate the entire viral lytic life cycle including lytic viral DNA replication, late-gene expression with appropriate kinetics, and virus release. In HH-B2, a newly established primary effusion lymphoma (PEL) cell line, KSHV ORF50 behaved as an immediate-early gene and autostimulated its own expression. Expression of late genes, ORF65, and K8.1 induced by KSHV Rta was eliminated by phosphonoacetic acid, an inhibitor of viral DNA polymerase. Transfection of KSHV Rta increased the production of encapsidated DNase-resistant viral DNA from HH-B2 cells. Thus, introduction of an ORF50 expression plasmid is sufficient to drive the lytic cycle to completion in cultured PEL cells. PMID:10846108

  14. Exploring the DNA binding interactions of the Kaposi's sarcoma-associated herpesvirus lytic switch protein by selective amplification of bound sequences in vitro.

    PubMed

    Ziegelbauer, Joseph; Grundhoff, Adam; Ganem, Don

    2006-03-01

    The lytic switch protein RTA of Kaposi's sarcoma-associated herpesvirus (KSHV) can be targeted to DNA by either direct sequence-specific recognition or via protein-protein interactions with host transcription factors. We have searched for sequences capable of direct RTA binding by screening synthetic oligonucleotide pools and KSHV genomic libraries for RTA-interacting elements, using repeated cycles of in vitro binding followed by amplification of the bound sequences. Multiple low-affinity sequences were recovered from the random pools, with generation of only a weak consensus sequence. The genomic library, by contrast, yielded many biologically relevant fragments, most of which could be shown to interact with RTA in vitro and some of which likely play important regulatory roles in vivo. Surprisingly, the most highly selected fragment came from the promoter of a late gene (gB) and contained at least two direct RTA binding sites, as well as one RBP-Jkappa binding site. This raises the possibility that some late KSHV genes may also be subject to direct RTA regulation, though indirect models are not excluded.

  15. Assay Development and High-Throughput Screening for Inhibitors of Kaposi's Sarcoma-Associated Herpesvirus N-Terminal Latency-Associated Nuclear Antigen Binding to Nucleosomes.

    PubMed

    Beauchemin, Chantal; Moerke, Nathan J; Faloon, Patrick; Kaye, Kenneth M

    2014-07-01

    Kaposi's sarcoma-associated herpesvirus (KSHV) has a causative role in several human malignancies, especially in immunocompromised hosts. KSHV latently infects tumor cells and persists as an extrachromosomal episome (plasmid). KSHV latency-associated nuclear antigen (LANA) mediates KSHV episome persistence. LANA binds specific KSHV sequence to replicate viral DNA. In addition, LANA tethers KSHV genomes to mitotic chromosomes to efficiently segregate episomes to daughter nuclei after mitosis. N-terminal LANA (N-LANA) binds histones H2A and H2B to attach to chromosomes. Currently, there are no specific inhibitors of KSHV latent infection. To enable high-throughput screening (HTS) of inhibitors of N-LANA binding to nucleosomes, here we develop, miniaturize, and validate a fluorescence polarization (FP) assay that detects fluorophore-labeled N-LANA peptide binding to nucleosomes. We also miniaturize a counterscreen to identify DNA intercalators that nonspecifically inhibit N-LANA binding to nucleosomes, and also develop an enzyme-linked immunosorbent assay to assess N-LANA binding to nucleosomes in the absence of fluorescence. HTS of libraries containing more than 350,000 compounds identified multiple compounds that inhibited N-LANA binding to nucleosomes. No compounds survived all counterscreens, however. More complex small-molecule libraries will likely be necessary to identify specific inhibitors of N-LANA binding to histones H2A and H2B; these assays should prove useful for future screens.

  16. Selective peptide inhibitors of antiapoptotic cellular and viral Bcl-2 proteins lead to cytochrome c release during latent Kaposi's sarcoma-associated herpesvirus infection.

    PubMed

    Burrer, Christine M; Foight, Glenna W; Keating, Amy E; Chan, Gary C

    2016-01-04

    Kaposi's sarcoma-associated herpesvirus (KSHV) is associated with B-cell lymphomas including primary effusion lymphoma and multicentric Castleman's disease. KSHV establishes latency within B cells by modulating or mimicking the antiapoptotic Bcl-2 family of proteins to promote cell survival. Our previous BH3 profiling analysis, a functional assay that assesses the contribution of Bcl-2 proteins towards cellular survival, identified two Bcl-2 proteins, cellular Mcl-1 and viral KsBcl-2, as potential regulators of mitochondria polarization within a latently infected B-cell line, Bcbl-1. In this study, we used two novel peptide inhibitors identified in a peptide library screen that selectively bind KsBcl-2 (KL6-7_Y4eK) or KsBcl-2 and Mcl-1 (MS1) in order to decipher the relative contribution of Mcl-1 and KsBcl-2 in maintaining mitochondrial membrane potential. We found treatment with KL6-7_Y4eK and MS1 stimulated a similar amount of cytochrome c release from mitochondria isolated from Bcbl-1 cells, indicating that inhibition of KsBcl-2 alone is sufficient for mitochondrial outer membrane permiabilzation (MOMP) and thus apoptosis during a latent B cell infection. In turn, this study also identified and provides a proof-of-concept for the further development of novel KsBcl-2 inhibitors for the treatment of KSHV-associated B-cell lymphomas via the targeting of latently infected B cells.

  17. Mechanism of Glycyrrhizic Acid Inhibition of Kaposi's Sarcoma-Associated Herpesvirus: Disruption of CTCF-Cohesin-Mediated RNA Polymerase II Pausing and Sister Chromatid Cohesion ▿

    PubMed Central

    Kang, Hyojeung; Lieberman, Paul M.

    2011-01-01

    Glycyrrhizic acid (GA), a derivative of licorice, selectively inhibits the growth of lymphocytes latently infected with Kaposi's sarcoma-associated herpesvirus. The mechanism involves the deregulation of the multicistronic latency transcript, including the failure to generate the mature forms of viral mRNA encoding LANA. We show here that GA disrupts an RNA polymerase II (RNAPII) complex that accumulates at the CTCF-cohesin binding site within the first intron of the latency transcript. GA altered the enrichment of the RNAPII pausing complex, along with pausing factors SPT5 and NELF-A, at the intragenic CTCF-cohesin binding sites. GA blocked the interaction of cohesin subunit SMC3 with another cohesin subunit, RAD21, and reduced SPT5 interaction with RNAPII. Covalent coupling of GA to a solid support revealed that GA interacts with several cellular proteins, including SMC3 and SPT5, but not their respective interaction partners RAD21 and RNAPII. GA treatment also inhibited the transcription of some cellular genes, like c-myc, which contain a similar CTCF-cohesin binding site within the first intron. We also found that GA leads to a more general loss of sister chromatid cohesion for cellular chromosomes. These findings suggest that RNAPII pauses at intragenic CTCF-cohesin binding sites and that abrogation of this pausing by GA leads to loss of proper mRNA production and defects in sister chromatid cohesion, a process important for both viral and cellular chromosome stability. PMID:21880767

  18. Attenuation of the suppressive activity of cellular splicing factor SRSF3 by Kaposi sarcoma-associated herpesvirus ORF57 protein is required for RNA splicing.

    PubMed

    Majerciak, Vladimir; Lu, Mathew; Li, Xiaofan; Zheng, Zhi-Ming

    2014-11-01

    Kaposi sarcoma-associated herpesvirus (KSHV) ORF57 is a multifunctional post-transcriptional regulator essential for viral gene expression during KSHV lytic infection. ORF57 requires interactions with various cellular proteins for its function. Here, we identified serine/arginine-rich splicing factor 3 (SRSF3, formerly known as SRp20) as a cellular cofactor involved in ORF57-mediated splicing of KSHV K8β RNA. In the absence of ORF57, SRSF3 binds to a suboptimal K8β intron and inhibits K8β splicing. Knockdown of SRSF3 promotes K8β splicing, mimicking the effect of ORF57. The N-terminal half of ORF57 binds to the RNA recognition motif of SRSF3, which prevents SRSF3 from associating with the K8β intron RNA and therefore attenuates the suppressive effect of SRSF3 on K8β splicing. ORF57 also promotes splicing of heterologous non-KSHV transcripts that are negatively regulated by SRSF3, indicating that the effect of ORF57 on SRSF3 activity is independent of RNA target. SPEN proteins, previously identified as ORF57-interacting partners, suppress ORF57 splicing activity by displacing ORF57 from SRSF3-RNA complexes. In summary, we have identified modulation of SRSF3 activity as the molecular mechanism by which ORF57 promotes RNA splicing.

  19. Capsid Structure of Kaposi's Sarcoma-Associated Herpesvirus, a Gammaherpesvirus, Compared to Those of an Alphaherpesvirus, Herpes Simplex Virus Type 1, and a Betaherpesvirus, Cytomegalovirus

    PubMed Central

    Trus, Benes L.; Heymann, J. Bernard; Nealon, Karin; Cheng, Naiqian; Newcomb, William W.; Brown, Jay C.; Kedes, Dean H.; Steven, Alasdair C.

    2001-01-01

    The capsid of Kaposi's sarcoma-associated herpesvirus (KSHV) was visualized at 24-Å resolution by cryoelectron microscopy. Despite limited sequence similarity between corresponding capsid proteins, KSHV has the same T=16 triangulation number and much the same capsid architecture as herpes simplex virus (HSV) and cytomegalovirus (CMV). Its capsomers are hexamers and pentamers of the major capsid protein, forming a shell with a flat, close-packed, inner surface (the “floor”) and chimney-like external protrusions. Overlying the floor at trigonal positions are (αβ2) heterotrimers called triplexes. The floor structure is well conserved over all three viruses, and the most variable capsid features reside on the outer surface, i.e., in the shapes of the protrusions and triplexes, in which KSHV resembles CMV and differs from HSV. Major capsid protein sequences from the three subfamilies have some similarity, which is closer between KSHV and CMV than between either virus and HSV. The triplex proteins are less highly conserved, but sequence analysis identifies relatively conserved tracts. In alphaherpesviruses, the α-subunit (VP19c in HSV) has a 100-residue N-terminal extension and an insertion near the C terminus. The small basic capsid protein sequences are highly divergent: whereas the HSV and CMV proteins bind only to hexons, difference mapping suggests that the KSHV protein, ORF65, binds around the tips of both hexons and pentons. PMID:11222713

  20. Complex alternative cytoplasmic protein isoforms of the Kaposi's sarcoma-associated herpesvirus latency-associated nuclear antigen 1 generated through noncanonical translation initiation.

    PubMed

    Toptan, Tuna; Fonseca, Lidia; Kwun, Hyun Jin; Chang, Yuan; Moore, Patrick S

    2013-03-01

    Kaposi's sarcoma-associated herpesvirus (KSHV) latency associated-nuclear antigen 1 (LANA1) protein is constitutively expressed in all KSHV-infected cells, as well as in all forms of KSHV-associated malignancies. LANA1 is a multifunctional KSHV oncoprotein containing multiple repeat sequences that is important for viral episome maintenance and the regulation of cellular and viral gene expression. We characterize here multiple LANA1 isoforms and show that ∼50% of LANA1 is naturally generated as N-terminally truncated shoulder proteins that are detected on SDS-PAGE as faster-migrating shoulder bands designated LANA1(S). Higher-molecular-weight LANA1(S) isoforms initiate downstream at noncanonical sites within the N-terminal region, whereas lower-molecular-weight LANA1(S) isoforms initiate downstream within the central repeat 1 domain. LANA1(S) proteins lack an N-terminal nuclear localization signal motif, and some isoforms differ from full-length, canonical LANA1 by localizing to perinuclear and cytoplasmic sites. Although LANA1 has until now been assumed to be solely active in the nucleus, this finding indicates that this major KSHV oncoprotein may have cytoplasmic activities as well. KSHV overcomes its limited genetic coding capacity by generating alternatively initiated protein isoforms that may have distinct biological functions.

  1. Kaposi sarcoma associated with lipoedema.

    PubMed

    Ekmekci, T R; Ayabakan, O; Sakiz, D; Koslu, A

    2005-05-01

    Lipoedema is a form of lipodistrophy, which consists of abnormal accumulation of fat in subcutaneous tissue of the lower limbs. It does not cause any disease and it has not been reported association with malignity. We describe a 63-year-old woman occurring of Kaposi sarcoma on the lipoedema base.

  2. Azidothymidine Sensitizes Primary Effusion Lymphoma Cells to Kaposi Sarcoma-Associated Herpesvirus-Specific CD4+ T Cell Control and Inhibits vIRF3 Function

    PubMed Central

    Stürzl, Michael; Sabbah, Shereen

    2016-01-01

    Kaposi sarcoma-associated herpesvirus (KSHV) is linked with the development of Kaposi sarcoma and the B lymphocyte disorders primary effusion lymphoma (PEL) and multi-centric Castleman disease. T cell immunity limits KSHV infection and disease, however the virus employs multiple mechanisms to inhibit efficient control by these effectors. Thus KSHV-specific CD4+ T cells poorly recognize most PEL cells and even where they can, they are unable to kill them. To make KSHV-infected cells more sensitive to T cell control we treated PEL cells with the thymidine analogue azidothymidine (AZT), which sensitizes PEL lines to Fas-ligand and TRAIL challenge; effector mechanisms which T cells use. PELs co-cultured with KSHV-specific CD4+ T cells in the absence of AZT showed no control of PEL outgrowth. However in the presence of AZT PEL outgrowth was controlled in an MHC-restricted manner. To investigate how AZT sensitizes PELs to immune control we first examined BJAB cells transduced with individual KSHV-latent genes for their ability to resist apoptosis mediated by stimuli delivered through Fas and TRAIL receptors. This showed that in addition to the previously described vFLIP protein, expression of vIRF3 also inhibited apoptosis delivered by these stimuli. Importantly vIRF3 mediated protection from these apoptotic stimuli was inhibited in the presence of AZT as was a second vIRF3 associated phenotype, the downregulation of surface MHC class II. Although both vFLIP and vIRF3 are expressed in PELs, we propose that inhibiting vIRF3 function with AZT may be sufficient to restore T cell control of these tumor cells. PMID:27893813

  3. Ets-1 Is Required for the Activation of VEGFR3 during Latent Kaposi's Sarcoma-Associated Herpesvirus Infection of Endothelial Cells

    PubMed Central

    Gutierrez, Kimberley D.; Morris, Valerie A.; Wu, David; Barcy, Serge

    2013-01-01

    Kaposi's sarcoma-associated herpesvirus (KSHV), the etiologic agent of Kaposi's sarcoma (KS), is present in the predominant tumor cells of KS, the spindle cells. Spindle cells express markers of lymphatic endothelium and, interestingly, KSHV infection of blood endothelial cells reprograms them to a lymphatic endothelial cell phenotype. KSHV-induced reprogramming requires the activation of STAT3 and phosphatidylinositol 3 (PI3)/AKT through the activation of cellular receptor gp130. Importantly, KSHV-induced reprogramming is specific to endothelial cells, indicating that there are additional host genes that are differentially regulated during KSHV infection of endothelial cells that contribute to lymphatic reprogramming. We found that the transcription factor Ets-1 is highly expressed in KS spindle cells and is upregulated during KSHV infection of endothelial cells in culture. The KSHV latent vFLIP gene is sufficient to induce Ets-1 expression in an NF-κB-dependent fashion. Ets-1 is required for KSHV-induced expression of VEGFR3, a lymphatic endothelial-cell-specific receptor important for lymphangiogenesis, and Ets-1 activates the promoter of VEGFR3. Ets-1 knockdown does not alter the expression of another lymphatic-specific gene, the podoplanin gene, but does inhibit the expression of VEGFR3 in uninfected lymphatic endothelium, indicating that Ets-1 is a novel cellular regulator of VEGFR3 expression. Knockdown of Ets-1 affects the ability of KSHV-infected cells to display angiogenic phenotypes, indicating that Ets-1 plays a role in KSHV activation of endothelial cells during latent KSHV infection. Thus, Ets-1 is a novel regulator of VEGFR3 and is involved in the induction of angiogenic phenotypes by KSHV. PMID:23552426

  4. Ets-1 is required for the activation of VEGFR3 during latent Kaposi's sarcoma-associated herpesvirus infection of endothelial cells.

    PubMed

    Gutierrez, Kimberley D; Morris, Valerie A; Wu, David; Barcy, Serge; Lagunoff, Michael

    2013-06-01

    Kaposi's sarcoma-associated herpesvirus (KSHV), the etiologic agent of Kaposi's sarcoma (KS), is present in the predominant tumor cells of KS, the spindle cells. Spindle cells express markers of lymphatic endothelium and, interestingly, KSHV infection of blood endothelial cells reprograms them to a lymphatic endothelial cell phenotype. KSHV-induced reprogramming requires the activation of STAT3 and phosphatidylinositol 3 (PI3)/AKT through the activation of cellular receptor gp130. Importantly, KSHV-induced reprogramming is specific to endothelial cells, indicating that there are additional host genes that are differentially regulated during KSHV infection of endothelial cells that contribute to lymphatic reprogramming. We found that the transcription factor Ets-1 is highly expressed in KS spindle cells and is upregulated during KSHV infection of endothelial cells in culture. The KSHV latent vFLIP gene is sufficient to induce Ets-1 expression in an NF-κB-dependent fashion. Ets-1 is required for KSHV-induced expression of VEGFR3, a lymphatic endothelial-cell-specific receptor important for lymphangiogenesis, and Ets-1 activates the promoter of VEGFR3. Ets-1 knockdown does not alter the expression of another lymphatic-specific gene, the podoplanin gene, but does inhibit the expression of VEGFR3 in uninfected lymphatic endothelium, indicating that Ets-1 is a novel cellular regulator of VEGFR3 expression. Knockdown of Ets-1 affects the ability of KSHV-infected cells to display angiogenic phenotypes, indicating that Ets-1 plays a role in KSHV activation of endothelial cells during latent KSHV infection. Thus, Ets-1 is a novel regulator of VEGFR3 and is involved in the induction of angiogenic phenotypes by KSHV.

  5. Kaposi's Sarcoma-Associated Herpesvirus MicroRNAs Target GADD45B To Protect Infected Cells from Cell Cycle Arrest and Apoptosis.

    PubMed

    Liu, Xiaoyan; Happel, Christine; Ziegelbauer, Joseph M

    2017-02-01

    Kaposi's sarcoma is one of the most common malignancies in HIV-infected individuals. The responsible agent, Kaposi's sarcoma-associated herpesvirus (KSHV; HHV8), expresses multiple microRNAs (miRNAs), but the targets and functions of these miRNAs are not completely understood. After infection in primary endothelial cells with KSHV, growth arrest DNA damage-inducible gene 45 beta (GADD45B) is one of the most repressed genes using genomic expression profiling. GADD45B was also repressed in mRNA expression profiling experiments when KSHV miRNAs were introduced to uninfected cells. We hypothesized that KSHV miRNAs target human GADD45B to protect cells from consequences of DNA damage, which can be triggered by viral infection. Expression of GADD45B protein is induced by the p53 activator, Nutlin-3, and KSHV miRNA-K9 inhibits this induction. In addition, Nutlin-3 increased apoptosis and cell cycle arrest based on flow cytometry assays. KSHV miR-K9 protected primary endothelial cells from apoptosis and cell cycle arrest following Nutlin-3 treatment. Similar protective phenotypes were seen for targeting GADD45B with short interfering RNAs (siRNAs), as with miR-K9. KSHV miR-K9 also decreased the protein levels of cleaved caspase-3, cleaved caspase-7, and cleaved poly(ADP-ribose) polymerase (PARP). In B lymphocytes latently infected with KSHV, specific inhibitors of KSHV miR-K9 led to increased GADD45B expression and apoptosis, indicating that miR-K9 is important for reducing apoptosis in infected cells. Furthermore, ectopic expression of GADD45B in KSHV-infected cells promoted apoptosis. Together, these results identify a new miRNA target and demonstrate that KSHV miRNAs are important for protecting infected cells from DNA damage responses.

  6. Transcriptional activation by the Kaposi's sarcoma-associated herpesvirus latency-associated nuclear antigen is facilitated by an N-terminal chromatin-binding motif.

    PubMed

    Wong, Lai-Yee; Matchett, Gerald A; Wilson, Angus C

    2004-09-01

    In immunocompromised patients, infection with Kaposi's sarcoma-associated herpesvirus (KSHV) can give rise to Kaposi's sarcoma and several lymphoproliferative disorders. In these tumors, KSHV establishes a latent infection in many of the rapidly proliferating and morphologically abnormal cells. Only a few viral gene products are expressed by the latent virus, and one of the best characterized is the latency-associated nuclear antigen (LANA), a nuclear protein required for the maintenance of viral episomal DNA in the dividing host cell. LANA can also activate or repress an assortment of cellular and viral promoters and may contribute to pathogenesis by allowing the proliferation and survival of host cells. Here we show that activation of the human E2F1 and cyclin-dependent kinase-2 (CDK2) promoters requires elements from both the N- and C-terminal regions of LANA. Deletion of the first 22 amino acids, which are necessary for episome tethering, does not affect nuclear localization but significantly reduces transactivation. Within the deleted peptide, we have identified a short sequence, termed the chromatin-binding motif (CBM), that binds tightly to interphase and mitotic chromatin. A second chromatin-binding activity resides in the C terminus but is not sufficient for optimal transactivation. Alanine substitutions within the CBM reveal a close correlation between the transactivation and chromatin binding activities, implying a mechanistic link. In contrast to promoter activation, we find that the 223 amino acids of the LANA C terminus are sufficient to inhibit p53-mediated activation of the human BAX promoter, indicating that the CBM is not required for all transcription-related functions.

  7. Long-Term-Infected Telomerase-Immortalized Endothelial Cells: a Model for Kaposi's Sarcoma-Associated Herpesvirus Latency In Vitro and In Vivo†

    PubMed Central

    An, Feng-Qi; Folarin, Hope Merlene; Compitello, Nicole; Roth, Justin; Gerson, Stanton L.; McCrae, Keith R.; Fakhari, Farnaz D.; Dittmer, Dirk P.; Renne, Rolf

    2006-01-01

    Kaposi's sarcoma-associated herpesvirus (KSHV) is associated with Kaposi's sarcoma (KS), primary effusion lymphoma (PEL), and multicentric Castleman's disease. Most KS tumor cells are latently infected with KSHV and are of endothelial origin. While PEL-derived cell lines maintain KSHV indefinitely, all KS tumor-derived cells to date have lost viral genomes upon ex vivo cultivation. To study KSHV latency and tumorigenesis in endothelial cells, we generated telomerase-immortalized human umbilical vein endothelial (TIVE) cells. TIVE cells express all KSHV latent genes 48 h postinfection, and productive lytic replication could be induced by RTA/Orf50. Similar to prior models, infected cultures gradually lost viral episomes. However, we also obtained, for the first time, two endothelial cell lines in which KSHV episomes were maintained indefinitely in the absence of selection. Long-term KSHV maintenance correlated with loss of reactivation in response to RTA/Orf50 and complete oncogenic transformation. Long-term-infected TIVE cells (LTC) grew in soft agar and proliferated under reduced-serum conditions. LTC, but not parental TIVE cells, formed tumors in nude mice. These tumors expressed high levels of the latency-associated nuclear antigen (LANA) and expressed lymphatic endothelial specific antigens as found in KS (LYVE-1). Furthermore, host genes, like those encoding interleukin 6, vascular endothelial growth factor, and basic fibroblast growth factor, known to be highly expressed in KS lesions were also induced in LTC-derived tumors. KSHV-infected LTCs represent the first xenograft model for KS and should be of use to study KS pathogenesis and for the validation of anti-KS drug candidates. PMID:16641275

  8. Kaposi's Sarcoma-Associated Herpesvirus Transactivator Rta Induces Cell Cycle Arrest in G0/G1 Phase by Stabilizing and Promoting Nuclear Localization of p27kip

    PubMed Central

    Kumar, Pankaj

    2013-01-01

    The Kaposi's sarcoma-associated herpesvirus (KSHV) immediate-early gene, replication, and transcription activator (K-Rta) is a key viral protein that serves as the master regulator for viral lytic replication. In this study, we investigated the role of K-Rta in cell cycle regulation and found that the expression of K-Rta in doxycycline (Dox)-inducible BJAB cells induced cell cycle arrest in G0/G1 phase. Western blot analysis of key cell cycle regulators revealed that K-Rta-mediated cell cycle arrest was associated with a decrease in cyclin A and phosphorylated Rb (pS807/pS811) protein levels, both markers of S phase progression, and an increase in protein levels for p27, a cyclin-dependent kinase inhibitor. Further, we found that K-Rta does not affect the transcription of p27 but regulates p27 at the posttranslational level by inhibiting its proteosomal degradation. Immunofluorescence staining and cell fractionation experiments revealed largely nuclear compartmentalization of p27 in K-Rta-expressing cells, demonstrating that K-Rta not only stabilizes p27 but also modulates its cellular localization. Finally, short hairpin RNA knockdown of p27 significantly abrogates cell cycle arrest in K-Rta-expressing cells, supporting its key role in K-Rta-mediated cell cycle arrest. Our findings are consistent with previous studies which showed that expression of immediate-early genes of several herpesviruses, including herpes simplex virus, Epstein-Barr virus, and cytomegalovirus, results in cell cycle arrest at the G0/G1 phase, possibly to avoid competition for resources needed for host cell replication during the S phase. PMID:24067984

  9. Kaposi's Sarcoma-Associated Herpesvirus Latency-Associated Nuclear Antigen 1 Mimics Epstein-Barr Virus EBNA1 Immune Evasion through Central Repeat Domain Effects on Protein Processing▿

    PubMed Central

    Kwun, Hyun Jin; da Silva, Suzane Ramos; Shah, Ishita M.; Blake, Neil; Moore, Patrick S.; Chang, Yuan

    2007-01-01

    Kaposi's sarcoma-associated herpesvirus (KSHV/human herpesvirus 8 [HHV8]) and Epstein-Barr virus (EBV/HHV4) are distantly related gammaherpesviruses causing tumors in humans. KSHV latency-associated nuclear antigen 1 (LANA1) is functionally similar to the EBV nuclear antigen-1 (EBNA1) protein expressed during viral latency, although they have no amino acid similarities. EBNA1 escapes cytotoxic lymphocyte (CTL) antigen processing by inhibiting its own proteosomal degradation and retarding its own synthesis to reduce defective ribosomal product processing. We show here that the LANA1 QED-rich central repeat (CR) region, particularly the CR2CR3 subdomain, also retards LANA1 synthesis and markedly enhances LANA1 stability in vitro and in vivo. LANA1 isoforms have half-lives greater than 24 h, and fusion of the LANA1 CR2CR3 domain to a destabilized heterologous protein markedly decreases protein turnover. Unlike EBNA1, the LANA1 CR2CR3 subdomain retards translation regardless of whether it is fused to the 5′ or 3′ end of a heterologous gene construct. Manipulation of sequence order, orientation, and composition of the CR2 and CR3 subdomains suggests that specific peptide sequences rather than RNA structures are responsible for synthesis retardation. Although mechanistic differences exist between LANA1 and EBNA1, the primary structures of both proteins have evolved to minimize provoking CTL immune responses. Simple strategies to eliminate these viral inhibitory regions may markedly improve vaccine effectiveness by maximizing CTL responses. PMID:17522213

  10. A Structural Basis for BRD2/4-Mediated Host Chromatin Interaction and Oligomer Assembly of Kaposi Sarcoma-Associated Herpesvirus and Murine Gammaherpesvirus LANA Proteins

    PubMed Central

    Krausze, Joern; Richter, Ulrike; Adler, Heiko; Fedorov, Roman; Pietrek, Marcel; Rückert, Jessica; Ritter, Christiane; Schulz, Thomas F.; Lührs, Thorsten

    2013-01-01

    Kaposi sarcoma-associated herpesvirus (KSHV) establishes a lifelong latent infection and causes several malignancies in humans. Murine herpesvirus 68 (MHV-68) is a related γ2-herpesvirus frequently used as a model to study the biology of γ-herpesviruses in vivo. The KSHV latency-associated nuclear antigen (kLANA) and the MHV68 mLANA (orf73) protein are required for latent viral replication and persistence. Latent episomal KSHV genomes and kLANA form nuclear microdomains, termed ‘LANA speckles’, which also contain cellular chromatin proteins, including BRD2 and BRD4, members of the BRD/BET family of chromatin modulators. We solved the X-ray crystal structure of the C-terminal DNA binding domains (CTD) of kLANA and MHV-68 mLANA. While these structures share the overall fold with the EBNA1 protein of Epstein-Barr virus, they differ substantially in their surface characteristics. Opposite to the DNA binding site, both kLANA and mLANA CTD contain a characteristic lysine-rich positively charged surface patch, which appears to be a unique feature of γ2-herpesviral LANA proteins. Importantly, kLANA and mLANA CTD dimers undergo higher order oligomerization. Using NMR spectroscopy we identified a specific binding site for the ET domains of BRD2/4 on kLANA. Functional studies employing multiple kLANA mutants indicate that the oligomerization of native kLANA CTD dimers, the characteristic basic patch and the ET binding site on the kLANA surface are required for the formation of kLANA ‘nuclear speckles’ and latent replication. Similarly, the basic patch on mLANA contributes to the establishment of MHV-68 latency in spleen cells in vivo. In summary, our data provide a structural basis for the formation of higher order LANA oligomers, which is required for nuclear speckle formation, latent replication and viral persistence. PMID:24146614

  11. p130Cas Scaffolds the Signalosome To Direct Adaptor-Effector Cross Talk during Kaposi's Sarcoma-Associated Herpesvirus Trafficking in Human Microvascular Dermal Endothelial Cells

    PubMed Central

    Bandyopadhyay, Chirosree; Veettil, Mohanan Valiya; Dutta, Sujoy

    2014-01-01

    ABSTRACT Kaposi's sarcoma-associated herpesvirus (KSHV) interacts with cell surface receptors, such as heparan sulfate, integrins (α3β1, αVβ3, and αVβ5), and EphrinA2 (EphA2), and activates focal adhesion kinase (FAK), Src, phosphoinositol 3-kinase (PI3-K), c-Cbl, and RhoA GTPase signal molecules early during lipid raft (LR)-dependent productive macropinocytic entry into human dermal microvascular endothelial cells. Our recent studies have identified CIB1 as a signal amplifier facilitating EphA2 phosphorylation and subsequent cytoskeletal cross talk during KSHV macropinocytosis. Although CIB1 lacks an enzymatic activity and traditional adaptor domain or known interacting sequence, it associated with the KSHV entry signal complex and the CIB1-KSHV association was sustained over 30 min postinfection. To identify factors scaffolding the EphA2-CIB1 signal axis, the role of major cellular scaffold protein p130Cas (Crk-associated substrate of Src) was investigated. Inhibitor and small interfering RNA (siRNA) studies demonstrated that KSHV induced p130Cas in an EphA2-, CIB1-, and Src-dependent manner. p130Cas and Crk were associated with KSHV, LRs, EphA2, and CIB1 early during infection. Live-cell microscopy and biochemical studies demonstrated that p130Cas knockdown did not affect KSHV entry but significantly reduced productive nuclear trafficking of viral DNA and routed KSHV to lysosomal degradation. p130Cas aided in scaffolding adaptor Crk to downstream guanine nucleotide exchange factor phospho-C3G possibly to coordinate GTPase signaling during KSHV trafficking. Collectively, these studies demonstrate that p130Cas acts as a bridging molecule between the KSHV-induced entry signal complex and the downstream trafficking signalosome in endothelial cells and suggest that simultaneous targeting of KSHV entry receptors with p130Cas would be an attractive potential avenue for therapeutic intervention in KSHV infection. IMPORTANCE Eukaryotic cell adaptor molecules

  12. p130Cas scaffolds the signalosome to direct adaptor-effector cross talk during Kaposi's sarcoma-associated herpesvirus trafficking in human microvascular dermal endothelial cells.

    PubMed

    Bandyopadhyay, Chirosree; Veettil, Mohanan Valiya; Dutta, Sujoy; Chandran, Bala

    2014-12-01

    Kaposi's sarcoma-associated herpesvirus (KSHV) interacts with cell surface receptors, such as heparan sulfate, integrins (α3β1, αVβ3, and αVβ5), and EphrinA2 (EphA2), and activates focal adhesion kinase (FAK), Src, phosphoinositol 3-kinase (PI3-K), c-Cbl, and RhoA GTPase signal molecules early during lipid raft (LR)-dependent productive macropinocytic entry into human dermal microvascular endothelial cells. Our recent studies have identified CIB1 as a signal amplifier facilitating EphA2 phosphorylation and subsequent cytoskeletal cross talk during KSHV macropinocytosis. Although CIB1 lacks an enzymatic activity and traditional adaptor domain or known interacting sequence, it associated with the KSHV entry signal complex and the CIB1-KSHV association was sustained over 30 min postinfection. To identify factors scaffolding the EphA2-CIB1 signal axis, the role of major cellular scaffold protein p130Cas (Crk-associated substrate of Src) was investigated. Inhibitor and small interfering RNA (siRNA) studies demonstrated that KSHV induced p130Cas in an EphA2-, CIB1-, and Src-dependent manner. p130Cas and Crk were associated with KSHV, LRs, EphA2, and CIB1 early during infection. Live-cell microscopy and biochemical studies demonstrated that p130Cas knockdown did not affect KSHV entry but significantly reduced productive nuclear trafficking of viral DNA and routed KSHV to lysosomal degradation. p130Cas aided in scaffolding adaptor Crk to downstream guanine nucleotide exchange factor phospho-C3G possibly to coordinate GTPase signaling during KSHV trafficking. Collectively, these studies demonstrate that p130Cas acts as a bridging molecule between the KSHV-induced entry signal complex and the downstream trafficking signalosome in endothelial cells and suggest that simultaneous targeting of KSHV entry receptors with p130Cas would be an attractive potential avenue for therapeutic intervention in KSHV infection. Eukaryotic cell adaptor molecules, without any intrinsic

  13. Convergence of Kaposi's sarcoma-associated herpesvirus reactivation with Epstein-Barr virus latency and cellular growth mediated by the notch signaling pathway in coinfected cells.

    PubMed

    Spadavecchia, Sophia; Gonzalez-Lopez, Olga; Carroll, Kyla Driscoll; Palmeri, Diana; Lukac, David M

    2010-10-01

    Kaposi's sarcoma-associated herpesvirus (KSHV) is the etiologic agent of primary effusion lymphoma (PEL). All PEL cell lines are infected with KSHV, and 70% are coinfected with Epstein-Barr virus (EBV). KSHV reactivation from latency requires promoter-specific transactivation by the KSHV Rta protein through interactions with RBP-Jk (CSL), the cellular DNA-binding component of the Notch signal transduction pathway. EBV transformation of primary B cells requires EBV nuclear antigen 2 (EBNA-2) to interact with RBP-Jk to direct the latent viral and cellular gene expression program. Although KSHV Rta and EBV EBNA-2 both require RBP-Jk for transactivation, previous studies have suggested that RBP-Jk-dependent transactivators do not function identically. We have found that the EBV latent protein LMP-1 is expressed in less than 5% of KSHV(+)/EBV(+) PEL cells but is induced in an Rta-dependent fashion when KSHV reactivates. KSHV Rta transactivates the EBV latency promoters in an RBP-Jk-dependent fashion and forms a ternary complex with RBP-Jk on the promoters. In B cells that are conditionally transformed by EBV alone, we show that KSHV Rta complements a short-term EBNA-2 growth deficiency in an autocrine/paracrine manner. Complementation of EBNA-2 deficiency by Rta depends on RBP-Jk and LMP-1, and Rta transactivation is required for optimal growth of KSHV(+)/EBV(+) PEL lines. Our data suggest that Rta can contribute to EBV-driven cellular growth by transactivating RBP-Jk-dependent EBV latency genes. However, our data also suggest that EBNA-2 and Rta induce distinct alterations in the cellular proteomes that contribute to the growth of infected cells.

  14. Kaposi's sarcoma-associated herpesvirus ORF57 interacts with cellular RNA export cofactors RBM15 and OTT3 to promote expression of viral ORF59.

    PubMed

    Majerciak, Vladimir; Uranishi, Hiroaki; Kruhlak, Michael; Pilkington, Guy R; Massimelli, Maria Julia; Bear, Jenifer; Pavlakis, George N; Felber, Barbara K; Zheng, Zhi-Ming

    2011-02-01

    Kaposi's sarcoma-associated herpesvirus (KSHV) encodes ORF57, which promotes the accumulation of specific KSHV mRNA targets, including ORF59 mRNA. We report that the cellular export NXF1 cofactors RBM15 and OTT3 participate in ORF57-enhanced expression of KSHV ORF59. We also found that ectopic expression of RBM15 or OTT3 augments ORF59 production in the absence of ORF57. While RBM15 promotes the accumulation of ORF59 RNA predominantly in the nucleus compared to the levels in the cytoplasm, we found that ORF57 shifted the nucleocytoplasmic balance by increasing ORF59 RNA accumulation in the cytoplasm more than in the nucleus. By promoting the accumulation of cytoplasmic ORF59 RNA, ORF57 offsets the nuclear RNA accumulation mediated by RBM15 by preventing nuclear ORF59 RNA from hyperpolyadenylation. ORF57 interacts directly with the RBM15 C-terminal portion containing the SPOC domain to reduce RBM15 binding to ORF59 RNA. Although ORF57 homologs Epstein-Barr virus (EBV) EB2, herpes simplex virus (HSV) ICP27, varicella-zoster virus (VZV) IE4/ORF4, and cytomegalovirus (CMV) UL69 also interact with RBM15 and OTT3, EBV EB2, which also promotes ORF59 expression, does not function like KSHV ORF57 to efficiently prevent RBM15-mediated nuclear accumulation of ORF59 RNA and RBM15's association with polyadenylated RNAs. Collectively, our data provide novel insight elucidating a molecular mechanism by which ORF57 promotes the expression of viral intronless genes.

  15. Kaposi's sarcoma-associated herpesvirus microRNA single-nucleotide polymorphisms identified in clinical samples can affect microRNA processing, level of expression, and silencing activity.

    PubMed

    Han, Soo-Jin; Marshall, Vickie; Barsov, Eugene; Quiñones, Octavio; Ray, Alex; Labo, Nazzarena; Trivett, Matthew; Ott, David; Renne, Rolf; Whitby, Denise

    2013-11-01

    Kaposi's sarcoma-associated herpesvirus (KSHV) encodes 12 pre-microRNAs that can produce 25 KSHV mature microRNAs. We previously reported single-nucleotide polymorphisms (SNPs) in KSHV-encoded pre-microRNA and mature microRNA sequences from clinical samples (V. Marshall et al., J. Infect. Dis., 195:645-659, 2007). To determine whether microRNA SNPs affect pre-microRNA processing and, ultimately, mature microRNA expression levels, we performed a detailed comparative analysis of (i) mature microRNA expression levels, (ii) in vitro Drosha/Dicer processing, and (iii) RNA-induced silencing complex-dependent targeting of wild-type (wt) and variant microRNA genes. Expression of pairs of wt and variant pre-microRNAs from retroviral vectors and measurement of KSHV mature microRNA expression by real-time reverse transcription-PCR (RT-PCR) revealed differential expression levels that correlated with the presence of specific sequence polymorphisms. Measurement of KSHV mature microRNA expression in a panel of primary effusion lymphoma cell lines by real-time RT-PCR recapitulated some observed expression differences but suggested a more complex relationship between sequence differences and expression of mature microRNA. Furthermore, in vitro maturation assays demonstrated significant SNP-associated changes in Drosha/DGCR8 and/or Dicer processing. These data demonstrate that SNPs within KSHV-encoded pre-microRNAs are associated with differential microRNA expression levels. Given the multiple reports on the involvement of microRNAs in cancer, the biological significance of these phenotypic and genotypic variants merits further studies in patients with KSHV-associated malignancies.

  16. Accumulation of Heterochromatin Components on the Terminal Repeat Sequence of Kaposi's Sarcoma-Associated Herpesvirus Mediated by the Latency-Associated Nuclear Antigen

    PubMed Central

    Sakakibara, Shuhei; Ueda, Keiji; Nishimura, Ken; Do, Eunju; Ohsaki, Eriko; Okuno, Toshiomi; Yamanishi, Koichi

    2004-01-01

    In the latent infection of Kaposi's sarcoma-associated herpesvirus (KSHV), its 160-kb circularized episomal DNA is replicated and maintained in the host nucleus. KSHV latency-associated nuclear antigen (LANA) is a key factor for maintaining viral latency. LANA binds to the terminal repeat (TR) DNA of the viral genome, leading to its localization to specific dot structures in the nucleus. In such an infected cell, the expression of the viral genes is restricted by a mechanism that is still unclear. Here, we found that LANA interacts with SUV39H1 histone methyltransferase, a key component of heterochromatin formation, as determined by use of a DNA pull-down assay with a biotinylated DNA fragment that contained a LANA-specific binding sequence and a maltose-binding protein pull-down assay. The diffuse localization of LANA on the chromosomes of uninfected cells changed to a punctate one with the introduction of a bacterial artificial chromosome containing most of the TR region, and SUV39H1 clearly colocalized with the LANA-associated dots. Thus, the LANA foci in KSHV-infected cells seemed to include SUV39H1 as well as heterochromatin protein 1. Furthermore, a chromatin immunoprecipitation assay revealed that the TR and the open reading frame (ORF) K1 and ORF50/RTA genes, but not the ORF73/LANA gene, lay within the heterochromatin during KSHV latency. Taken together, these observations indicate that LANA recruits heterochromatin components to the viral genome, which may lead to the establishment of viral latency and govern the transcription program. PMID:15220403

  17. Two Subclasses of Kaposi's Sarcoma-Associated Herpesvirus Lytic Cycle Promoters Distinguished by Open Reading Frame 50 Mutant Proteins That Are Deficient in Binding to DNA

    PubMed Central

    Chang, Pey-Jium; Shedd, Duane; Miller, George

    2005-01-01

    A transcriptional activator encoded in open reading frame 50 (ORF50) of the Kaposi's sarcoma-associated herpesvirus (KSHV) genome initiates the viral lytic cycle. Here we classify four lytic cycle genes on the basis of several characteristics of the ORF50 response elements (ORF50 REs) in their promoters: nucleotide sequence homology, the capacity to bind ORF50 protein in vitro, the ability to bind the cellular protein RBP-Jκ in vitro, and the capacity to confer activation by DNA binding-deficient mutants of ORF50 protein. ORF50 expressed in human cells binds the promoters of PAN and K12 but does not bind ORF57 or vMIP-1 promoters. Conversely, the RBP-Jκ protein binds ORF57 and vMIP-1 but not PAN or K12 promoters. DNA binding-deficient mutants of ORF50 protein differentiate these two subclasses of promoters in reporter assays; the PAN and K12 promoters cannot be activated, while the ORF57 and vMIP-1 promoters are responsive. Although DNA binding-deficient mutants of ORF50 protein are defective in activating direct targets, they are nonetheless capable of activating the lytic cascade of KSHV. Significantly, DNA binding-deficient ORF50 mutants are competent to autostimulate expression of endogenous ORF50 and to autoactivate ORF50 promoter reporters. The experiments show that ORF50 protein activates downstream targets by at least two distinct mechanisms: one involves direct binding of ORF50 REs in promoter DNA; the other mechanism employs interactions with the RBP-Jκ cellular protein bound to promoter DNA in the region of the ORF50 RE. The DNA binding-deficient mutants allow classification of ORF50-responsive genes and will facilitate study of the several distinct mechanisms of activation of KSHV lytic cycle genes that are under the control of ORF50 protein. PMID:15994769

  18. Comparative Study of Kaposi's Sarcoma-Associated Herpesvirus Serological Assays Using Clinically and Serologically Defined Reference Standards and Latent Class Analysis▿

    PubMed Central

    Nascimento, Maria Claudia; de Souza, Vanda Akico; Sumita, Laura Masami; Freire, Wilton; Munoz, Fernando; Kim, Joseph; Pannuti, Claudio S.; Mayaud, Philippe

    2007-01-01

    Accurate determination of infection with Kaposi's sarcoma-associated herpesvirus (KSHV) has been hindered by the lack of a “gold standard” for comparison of serological assays used to estimate KSHV prevalence in serosurveys conducted in different settings. We have evaluated the performance of five in-house (developed at University College London [UCL], United Kingdom, and at the virology laboratory of the Instituto de Medicine Tropical [IMT] in Sao Paulo, Brazil) and two commercial (ABI and DIAVIR) serological assays to detect antibodies to latency-associated nuclear antigen (LANA) and to lytic KSHV antigens. We used a variety of serum samples assembled to represent populations likely to be at high, intermediate, and low risk of KSHV infection in Brazil. Composite reference standard panels were prepared based on clinical and serological parameters, against which assay performances were assessed using conventional Bayesian statistics and latent class analysis (LCA). Against the clinical reference standard, in-house immunofluorescence assays to detect anti-LANA antibodies (IFA-LANA) produced at UCL and IMT had similar performances, with sensitivities of 61% (95% confidence interval [CI], 48% to 74%) and 72% (95% CI, 58% to 83%) and specificities of 99% (95% CI, 94% to 100%) and 100% (95% CI, 96% to 100%), respectively, and only the IMT IFA-LANA was included in LCA, together with the IMT IFA-lytic and four enzyme-linked immunosorbent assays (ELISAs). The LCA indicated that the IMT whole-virus ELISA performed best (sensitivity, 87% [95% CI, 81% to 91%]; and specificity, 100% [95% CI, 98% to 100%]), confirming the results obtained with the conventional statistical approach. Commercially available ELISA-based tests yielded the lowest specificities using a spectrum of serum samples. The evaluation of KSHV serological assays is warranted before planning serosurveys in various settings. PMID:17182752

  19. Comparative study of Kaposi's sarcoma-associated herpesvirus serological assays using clinically and serologically defined reference standards and latent class analysis.

    PubMed

    Nascimento, Maria Claudia; de Souza, Vanda Akico; Sumita, Laura Masami; Freire, Wilton; Munoz, Fernando; Kim, Joseph; Pannuti, Claudio S; Mayaud, Philippe

    2007-03-01

    Accurate determination of infection with Kaposi's sarcoma-associated herpesvirus (KSHV) has been hindered by the lack of a "gold standard" for comparison of serological assays used to estimate KSHV prevalence in serosurveys conducted in different settings. We have evaluated the performance of five in-house (developed at University College London [UCL], United Kingdom, and at the virology laboratory of the Instituto de Medicine Tropical [IMT] in Sao Paulo, Brazil) and two commercial (ABI and DIAVIR) serological assays to detect antibodies to latency-associated nuclear antigen (LANA) and to lytic KSHV antigens. We used a variety of serum samples assembled to represent populations likely to be at high, intermediate, and low risk of KSHV infection in Brazil. Composite reference standard panels were prepared based on clinical and serological parameters, against which assay performances were assessed using conventional Bayesian statistics and latent class analysis (LCA). Against the clinical reference standard, in-house immunofluorescence assays to detect anti-LANA antibodies (IFA-LANA) produced at UCL and IMT had similar performances, with sensitivities of 61% (95% confidence interval [CI], 48% to 74%) and 72% (95% CI, 58% to 83%) and specificities of 99% (95% CI, 94% to 100%) and 100% (95% CI, 96% to 100%), respectively, and only the IMT IFA-LANA was included in LCA, together with the IMT IFA-lytic and four enzyme-linked immunosorbent assays (ELISAs). The LCA indicated that the IMT whole-virus ELISA performed best (sensitivity, 87% [95% CI, 81% to 91%]; and specificity, 100% [95% CI, 98% to 100%]), confirming the results obtained with the conventional statistical approach. Commercially available ELISA-based tests yielded the lowest specificities using a spectrum of serum samples. The evaluation of KSHV serological assays is warranted before planning serosurveys in various settings.

  20. Immunoreceptor tyrosine-based activation motif-dependent signaling by Kaposi's sarcoma-associated herpesvirus K1 protein: effects on lytic viral replication.

    PubMed

    Lagunoff, M; Lukac, D M; Ganem, D

    2001-07-01

    The Kaposi's sarcoma-associated herpesvirus (KSHV) K1 gene encodes a polypeptide bearing an immunoreceptor tyrosine-based activation motif (ITAM) that is constitutively active for ITAM-based signal transduction. Although ectopic overexpression of K1 in cultured fibroblasts can lead to growth transformation, in vivo this gene is primarily expressed in lymphoid cells undergoing lytic infection. Here we have examined function of K1 in the setting of lytic replication, through the study of K1 mutants lacking functional ITAMs. Expression of such mutants in BJAB cells cotransfected with wild-type K1 results in dramatic inhibition of K1 signal transduction, as judged by impaired activation of Syk kinase and phospholipase C-gamma2 as well as by diminished expression of a luciferase reporter gene dependent upon K1-induced calcium and Ras signaling. Thus, the mutants behave as dominantly acting inhibitors of K1 function. To assess the role of K1 in lytic replication, we introduced these K1 mutants into BCBL-1 cells, a B-cell lymphoma line latently infected with KSHV, and induced lytic replication by ectopic expression of the KSHV ORF50 transactivator. Expression of lytic cycle genes was diminished up to 80% in the presence of a K1 dominant negative mutant. These inhibitory effects could be overridden by tetradecanoyl phorbol acetate treatment, indicating that inhibition was not due to irreversible cell injury and suggesting that other signaling events could bypass the block. We conclude that ITAM-dependent signaling by K1 is not absolutely required for lytic reactivation but functions to modestly augment lytic replication in B cells, the natural reservoir of KSHV.

  1. Two subclasses of Kaposi's sarcoma-associated herpesvirus lytic cycle promoters distinguished by open reading frame 50 mutant proteins that are deficient in binding to DNA.

    PubMed

    Chang, Pey-Jium; Shedd, Duane; Miller, George

    2005-07-01

    A transcriptional activator encoded in open reading frame 50 (ORF50) of the Kaposi's sarcoma-associated herpesvirus (KSHV) genome initiates the viral lytic cycle. Here we classify four lytic cycle genes on the basis of several characteristics of the ORF50 response elements (ORF50 REs) in their promoters: nucleotide sequence homology, the capacity to bind ORF50 protein in vitro, the ability to bind the cellular protein RBP-Jkappa in vitro, and the capacity to confer activation by DNA binding-deficient mutants of ORF50 protein. ORF50 expressed in human cells binds the promoters of PAN and K12 but does not bind ORF57 or vMIP-1 promoters. Conversely, the RBP-Jkappa protein binds ORF57 and vMIP-1 but not PAN or K12 promoters. DNA binding-deficient mutants of ORF50 protein differentiate these two subclasses of promoters in reporter assays; the PAN and K12 promoters cannot be activated, while the ORF57 and vMIP-1 promoters are responsive. Although DNA binding-deficient mutants of ORF50 protein are defective in activating direct targets, they are nonetheless capable of activating the lytic cascade of KSHV. Significantly, DNA binding-deficient ORF50 mutants are competent to autostimulate expression of endogenous ORF50 and to autoactivate ORF50 promoter reporters. The experiments show that ORF50 protein activates downstream targets by at least two distinct mechanisms: one involves direct binding of ORF50 REs in promoter DNA; the other mechanism employs interactions with the RBP-Jkappa cellular protein bound to promoter DNA in the region of the ORF50 RE. The DNA binding-deficient mutants allow classification of ORF50-responsive genes and will facilitate study of the several distinct mechanisms of activation of KSHV lytic cycle genes that are under the control of ORF50 protein.

  2. An Sp1 response element in the Kaposi's sarcoma-associated herpesvirus open reading frame 50 promoter mediates lytic cycle induction by butyrate.

    PubMed

    Ye, Jianjiang; Shedd, Duane; Miller, George

    2005-02-01

    Kaposi's sarcoma-associated herpesvirus (KSHV) can be driven into the lytic cycle in vitro by phorbol esters and sodium butyrate. This report begins to analyze the process by which butyrate activates the promoter of KSHV open reading frame 50 (ORF50), the key viral regulator of the KSHV latency to lytic cycle switch. A short fragment of the promoter, 134 nucleotides upstream of the translational start of ORF50, retained basal uninduced activity and conferred maximal responsiveness to sodium butyrate. The butyrate response element was mapped to a consensus Sp1-binding site. By means of electrophoretic mobility shift assays, both Sp1 and Sp3 were shown to form complexes in vitro with the ORF50 promoter at the Sp1 site. Butyrate induced the formation of a group of novel complexes, including several Sp3-containing complexes, one Sp1-containing complex, and several other complexes that were not identified with antibodies to Sp1 or Sp3. Formation of all butyrate-induced DNA-protein complexes was mediated by the consensus Sp1 site. In insect and mammalian cell lines, Sp1 significantly activated the ORF50 promoter linked to luciferase. Chromatin immunoprecipitation experiments in a PEL cell line showed that butyrate induced Sp1, CBP, and p300 binding to the ORF50 promoter in vivo in an on-off manner. The results suggest that induction of the KSHV lytic cycle by butyrate is mediated through interactions at the Sp1/Sp3 site located 103 to 112 nucleotides upstream of the translational initiation of ORF50 presumably by enhancing the binding of Sp1 to this site.

  3. Kaposi's Sarcoma-Associated Herpesvirus MicroRNA Single-Nucleotide Polymorphisms Identified in Clinical Samples Can Affect MicroRNA Processing, Level of Expression, and Silencing Activity

    PubMed Central

    Han, Soo-Jin; Marshall, Vickie; Barsov, Eugene; Quiñones, Octavio; Ray, Alex; Labo, Nazzarena; Trivett, Matthew; Ott, David; Renne, Rolf

    2013-01-01

    Kaposi's sarcoma-associated herpesvirus (KSHV) encodes 12 pre-microRNAs that can produce 25 KSHV mature microRNAs. We previously reported single-nucleotide polymorphisms (SNPs) in KSHV-encoded pre-microRNA and mature microRNA sequences from clinical samples (V. Marshall et al., J. Infect. Dis., 195:645–659, 2007). To determine whether microRNA SNPs affect pre-microRNA processing and, ultimately, mature microRNA expression levels, we performed a detailed comparative analysis of (i) mature microRNA expression levels, (ii) in vitro Drosha/Dicer processing, and (iii) RNA-induced silencing complex-dependent targeting of wild-type (wt) and variant microRNA genes. Expression of pairs of wt and variant pre-microRNAs from retroviral vectors and measurement of KSHV mature microRNA expression by real-time reverse transcription-PCR (RT-PCR) revealed differential expression levels that correlated with the presence of specific sequence polymorphisms. Measurement of KSHV mature microRNA expression in a panel of primary effusion lymphoma cell lines by real-time RT-PCR recapitulated some observed expression differences but suggested a more complex relationship between sequence differences and expression of mature microRNA. Furthermore, in vitro maturation assays demonstrated significant SNP-associated changes in Drosha/DGCR8 and/or Dicer processing. These data demonstrate that SNPs within KSHV-encoded pre-microRNAs are associated with differential microRNA expression levels. Given the multiple reports on the involvement of microRNAs in cancer, the biological significance of these phenotypic and genotypic variants merits further studies in patients with KSHV-associated malignancies. PMID:24006441

  4. Kaposi's Sarcoma-Associated Herpesvirus Viral Interferon Regulatory Factor 4 (vIRF4) Perturbs the G1-S Cell Cycle Progression via Deregulation of the cyclin D1 Gene.

    PubMed

    Lee, Hye-Ra; Mitra, Jaba; Lee, Stacy; Gao, Shou-Jiang; Oh, Tae-Kwang; Kim, Myung Hee; Ha, Taekjip; Jung, Jae U

    2015-10-21

    Kaposi's sarcoma-associated herpesvirus (KSHV) infection modulates the host cell cycle to create an environment optimal for its viral-DNA replication during the lytic life cycle. We report here that KSHV vIRF4 targets the β-catenin/CBP cofactor and blocks its occupancy on the cyclin D1 promoter, suppressing the G1-S cell cycle progression and enhancing KSHV replication. This shows that KSHV vIRF4 suppresses host G1-S transition, possibly providing an intracellular milieu favorable for its replication.

  5. ORF33 and ORF38 of Kaposi's Sarcoma-Associated Herpesvirus Interact and Are Required for Optimal Production of Infectious Progeny Viruses

    PubMed Central

    Wu, Jian-jun; Avey, Denis; Li, Wenwei; Gillen, Joseph; Fu, Bishi; Miley, Wendell; Whitby, Denise

    2015-01-01

    ABSTRACT We recently showed that the interaction between Kaposi's sarcoma-associated herpesvirus (KSHV) tegument proteins ORF33 and ORF45 is crucial for progeny virion production, but the exact functions of KSHV ORF33 during lytic replication were unknown (J. Gillen, W. Li, Q. Liang, D. Avey, J. Wu, F. Wu, J. Myoung, and F. Zhu, J Virol 89:4918–4931, 2015, http://dx.doi.org/10.1128/JVI.02925-14). Therefore, here we investigated the relationship between ORF33 and ORF38, whose counterparts in both alpha- and betaherpesviruses interact with each other. Using specific monoclonal antibodies, we found that both proteins are expressed during the late lytic cycle with similar kinetics and that both are present in mature virions as components of the tegument. Furthermore, we confirmed that ORF33 interacts with ORF38. Interestingly, we observed that ORF33 tightly associates with the capsid, whereas ORF38 associates with the envelope. We generated ORF33-null, ORF38-null, and double-null mutants and found that these mutants apparently have identical phenotypes: the mutations caused no apparent effect on viral gene expression but reduced the yield of progeny virion by about 10-fold. The progeny virions also lack certain virion component proteins, including ORF45. During viral lytic replication, the virions associate with cytoplasmic vesicles. We also observed that ORF38 associates with the membranes of vesicles and colocalizes with the Golgi membrane or early endosome membrane. Further analyses of ORF33/ORF38 mutants revealed the reduced production of virion-containing vesicles, suggesting that ORF33 and ORF38 are involved in the transport of newly assembled viral particles into cytoplasmic vesicles, a process important for viral maturation and egress. IMPORTANCE Herpesvirus assembly is an essential step in virus propagation that leads to the generation of progeny virions. It is a complicated process that depends on the delicate regulation of interactions among virion

  6. Kaposi sarcoma-associated herpesvirus and response to antiretroviral therapy: A prospective study of HIV-infected adults

    PubMed Central

    Maskew, Mhairi; MacPhail, A Patrick; Whitby, Denise; Egger, Matthias; Fox, Matthew P.

    2013-01-01

    Background The possible impact of co-infection with Kaposi’s sarcoma associated herpes virus on the response to antiretroviral therapy (ART) is unknown. Prospective studies are rare, particularly in Africa. Methods We enrolled a prospective cohort of HIV-infected adults initiating ART in Johannesburg, South Africa. Subjects were defined as seropositive to KSHV if reactive to either KSHV lytic K8.1 or latent Orf73 antigen or both. Subjects were followed from ART initiation until 18-months on treatment. HIV viral load and CD4 counts were tested 6 monthly. Linear generalized estimating and log-binomial regression models were used to estimate the effect of KSHV infection on immunologic recovery and response as well as HIV viral load suppression within 18-months after ART initiation. Results 385 subjects initiating ART from November 2008-March 2009 were eligible including 184 (48%) KSHV+. The KSHV+ group was similar to the KSHV− in terms of age, gender, initiating CD4 count, body mass index, tuberculosis and haemoglobin levels. The KSHV+ group gained a similar number of cells at 6- (difference of 10 cells/mm3, 95% CI: −11–31), 12- (3 cells/mm3, 95% CI: −19–25) and 18-months (24 cells/mm3, 95% CI: −13–61) compared to the KSHV− group. Adjusted relative risk of failure to suppress viral load to <400 copies/mL (1.03; 95% CI: 0.90–1.17) were similar for KSHV+ and KSHV− by 6-months on treatment. Conclusions In a population with a high KSHV prevalence, HIV-positive adults co-infected with KSHV achieved similar immunologic and virologic responses to ART early after treatment initiation compared to those KSHV−. PMID:23614996

  7. Activation and repression of Epstein-Barr Virus and Kaposi's sarcoma-associated herpesvirus lytic cycles by short- and medium-chain fatty acids.

    PubMed

    Gorres, Kelly L; Daigle, Derek; Mohanram, Sudharshan; Miller, George

    2014-07-01

    The lytic cycles of Epstein-Barr virus (EBV) and Kaposi's sarcoma-associated herpesvirus (KSHV) are induced in cell culture by sodium butyrate (NaB), a short-chain fatty acid (SCFA) histone deacetylase (HDAC) inhibitor. Valproic acid (VPA), another SCFA and an HDAC inhibitor, induces the lytic cycle of KSHV but blocks EBV lytic reactivation. To explore the hypothesis that structural differences between NaB and VPA account for their functional effects on the two related viruses, we investigated the capacity of 16 structurally related short- and medium-chain fatty acids to promote or prevent lytic cycle reactivation. SCFAs differentially affected EBV and KSHV reactivation. KSHV was reactivated by all SCFAs that are HDAC inhibitors, including phenylbutyrate. However, several fatty acid HDAC inhibitors, such as isobutyrate and phenylbutyrate, did not reactivate EBV. Reactivation of KSHV lytic transcripts could not be blocked completely by any fatty acid tested. In contrast, several medium-chain fatty acids inhibited lytic activation of EBV. Fatty acids that blocked EBV reactivation were more lipophilic than those that activated EBV. VPA blocked activation of the BZLF1 promoter by NaB but did not block the transcriptional function of ZEBRA. VPA also blocked activation of the DNA damage response that accompanies EBV lytic cycle activation. Properties of SCFAs in addition to their effects on chromatin are likely to explain activation or repression of EBV. We concluded that fatty acids stimulate the two related human gammaherpesviruses to enter the lytic cycle through different pathways. Importance: Lytic reactivation of EBV and KSHV is needed for persistence of these viruses and plays a role in carcinogenesis. Our direct comparison highlights the mechanistic differences in lytic reactivation between related human oncogenic gammaherpesviruses. Our findings have therapeutic implications, as fatty acids are found in the diet and produced by the human microbiota. Small

  8. Primary B Lymphocytes Infected with Kaposi's Sarcoma-Associated Herpesvirus Can Be Expanded In Vitro and Are Recognized by LANA-Specific CD4+ T Cells

    PubMed Central

    Nicol, Samantha M.; Sabbah, Shereen; Brulois, Kevin F.; Jung, Jae U.; Bell, Andrew I.

    2016-01-01

    ABSTRACT Kaposi's sarcoma-associated herpesvirus (KSHV) has tropism for B lymphocytes, in which it establishes latency, and can also cause lymphoproliferative disorders of these cells manifesting as primary effusion lymphoma (PEL) and multicentric Castleman disease (MCD). T cell immunity is vital for the control of KSHV infection and disease; however, few models of B lymphocyte infection exist to study immune recognition of such cells. Here, we developed a model of B lymphocyte infection with KSHV in which infected tonsillar B lymphocytes were expanded by providing mitogenic stimuli and then challenged with KSHV-specific CD4+ T cells. The infected cells expressed viral proteins found in PELs, namely, LANA and viral IRF3 (vIRF3), albeit at lower levels, with similar patterns of gene expression for the major latency, viral interleukin 6 (vIL-6), and vIRF3 transcripts. Despite low-level expression of open reading frame 50 (ORF50), transcripts for the immune evasion genes K3 and K5 were detected, with some downregulation of cell surface-expressed CD86 and ICAM. The vast majority of infected lymphocytes expressed IgM heavy chains with Igλ light chains, recapitulating the features seen in infected cells in MCD. We assessed the ability of the infected lymphocytes to be targeted by a panel of major histocompatibility complex (MHC) class II-matched CD4+ T cells and found that LANA-specific T cells restricted to different epitopes recognized these infected cells. Given that at least some KSHV latent antigens are thought to be poor targets for CD8+ T cells, we suggest that CD4+ T cells are potentially important effectors for the in vivo control of KSHV-infected B lymphocytes. IMPORTANCE KSHV establishes a latent reservoir within B lymphocytes, but few models exist to study KSHV-infected B cells other than the transformed PEL cell lines, which have likely accrued mutations during the transformation process. We developed a model of KSHV-infected primary B lymphocytes that

  9. Activation and Repression of Epstein-Barr Virus and Kaposi's Sarcoma-Associated Herpesvirus Lytic Cycles by Short- and Medium-Chain Fatty Acids

    PubMed Central

    Gorres, Kelly L.; Daigle, Derek; Mohanram, Sudharshan

    2014-01-01

    ABSTRACT The lytic cycles of Epstein-Barr virus (EBV) and Kaposi's sarcoma-associated herpesvirus (KSHV) are induced in cell culture by sodium butyrate (NaB), a short-chain fatty acid (SCFA) histone deacetylase (HDAC) inhibitor. Valproic acid (VPA), another SCFA and an HDAC inhibitor, induces the lytic cycle of KSHV but blocks EBV lytic reactivation. To explore the hypothesis that structural differences between NaB and VPA account for their functional effects on the two related viruses, we investigated the capacity of 16 structurally related short- and medium-chain fatty acids to promote or prevent lytic cycle reactivation. SCFAs differentially affected EBV and KSHV reactivation. KSHV was reactivated by all SCFAs that are HDAC inhibitors, including phenylbutyrate. However, several fatty acid HDAC inhibitors, such as isobutyrate and phenylbutyrate, did not reactivate EBV. Reactivation of KSHV lytic transcripts could not be blocked completely by any fatty acid tested. In contrast, several medium-chain fatty acids inhibited lytic activation of EBV. Fatty acids that blocked EBV reactivation were more lipophilic than those that activated EBV. VPA blocked activation of the BZLF1 promoter by NaB but did not block the transcriptional function of ZEBRA. VPA also blocked activation of the DNA damage response that accompanies EBV lytic cycle activation. Properties of SCFAs in addition to their effects on chromatin are likely to explain activation or repression of EBV. We concluded that fatty acids stimulate the two related human gammaherpesviruses to enter the lytic cycle through different pathways. IMPORTANCE Lytic reactivation of EBV and KSHV is needed for persistence of these viruses and plays a role in carcinogenesis. Our direct comparison highlights the mechanistic differences in lytic reactivation between related human oncogenic gammaherpesviruses. Our findings have therapeutic implications, as fatty acids are found in the diet and produced by the human microbiota

  10. ESCRT-I Protein Tsg101 Plays a Role in the Post-macropinocytic Trafficking and Infection of Endothelial Cells by Kaposi's Sarcoma-Associated Herpesvirus.

    PubMed

    Kumar, Binod; Dutta, Dipanjan; Iqbal, Jawed; Ansari, Mairaj Ahmed; Roy, Arunava; Chikoti, Leela; Pisano, Gina; Veettil, Mohanan Valiya; Chandran, Bala

    2016-10-01

    Kaposi's sarcoma-associated herpesvirus (KSHV) binding to the endothelial cell surface heparan sulfate is followed by sequential interactions with α3β1, αVβ3 and αVβ5 integrins and Ephrin A2 receptor tyrosine kinase (EphA2R). These interactions activate host cell pre-existing FAK, Src, PI3-K and RhoGTPase signaling cascades, c-Cbl mediated ubiquitination of receptors, recruitment of CIB1, p130Cas and Crk adaptor molecules, and membrane bleb formation leading to lipid raft dependent macropinocytosis of KSHV into human microvascular dermal endothelial (HMVEC-d) cells. The Endosomal Sorting Complexes Required for Transport (ESCRT) proteins, ESCRT-0, -I, -II, and-III, play a central role in clathrin-mediated internalized ubiquitinated receptor endosomal trafficking and sorting. ESCRT proteins have also been shown to play roles in viral egress. We have recently shown that ESCRT-0 component Hrs protein associates with the plasma membrane during macropinocytosis and mediates KSHV entry via ROCK1 mediated phosphorylation of NHE1 and local membrane pH change. Here, we demonstrate that the ESCRT-I complex Tsg101 protein also participates in the macropinocytosis of KSHV and plays a role in KSHV trafficking. Knockdown of Tsg101 did not affect virus entry in HMVEC-d and human umbilical vein endothelial (HUVEC) cells but significantly inhibited the KSHV genome entry into the nucleus and consequently viral gene expression in these cells. Double and triple immunofluorescence, proximity ligation immunofluorescence and co-immuoprecipitation studies revealed the association of Tsg101 with the KSHV containing macropinosomes, and increased levels of Tsg101 association/interactions with EphA2R, c-Cbl, p130Cas and Crk signal molecules, as well as with upstream and downstream ESCRT components such as Hrs (ESCRT-0), EAP45 (ESCRT-II), CHMP6 (ESCRT-III) and CHMP5 (ESCRT-III) in the KSHV infected cells. Tsg101 was also associated with early (Rab5) and late endosomal (Rab7) stages of

  11. Ago HITS-CLIP Expands Understanding of Kaposi's Sarcoma-associated Herpesvirus miRNA Function in Primary Effusion Lymphomas

    PubMed Central

    Haecker, Irina; Gay, Lauren A.; Yang, Yajie; Hu, Jianhong; Morse, Alison M.; McIntyre, Lauren M.; Renne, Rolf

    2012-01-01

    KSHV is the etiological agent of Kaposi's sarcoma (KS), primary effusion lymphoma (PEL), and a subset of multicentricCastleman's disease (MCD). The fact that KSHV-encoded miRNAs are readily detectable in all KSHV-associated tumors suggests a potential role in viral pathogenesis and tumorigenesis. MiRNA-mediated regulation of gene expression is a complex network with each miRNA having many potential targets, and to date only few KSHV miRNA targets have been experimentally determined. A detailed understanding of KSHV miRNA functions requires high-through putribonomics to globally analyze putative miRNA targets in a cell type-specific manner. We performed Ago HITS-CLIP to identify viral and cellular miRNAs and their cognate targets in two latently KSHV-infected PEL cell lines. Ago HITS-CLIP recovered 1170 and 950 cellular KSHVmiRNA targets from BCBL-1 and BC-3, respectively. Importantly, enriched clusters contained KSHV miRNA seed matches in the 3′UTRs of numerous well characterized targets, among them THBS1, BACH1, and C/EBPβ. KSHV miRNA targets were strongly enriched for genes involved in multiple pathways central for KSHV biology, such as apoptosis, cell cycle regulation, lymphocyte proliferation, and immune evasion, thus further supporting a role in KSHV pathogenesis and potentially tumorigenesis. A limited number of viral transcripts were also enriched by HITS-CLIP including vIL-6 expressed only in a subset of PEL cells during latency. Interestingly, Ago HITS-CLIP revealed extremely high levels of Ago-associated KSHV miRNAs especially in BC-3 cells where more than 70% of all miRNAs are of viral origin. This suggests that in addition to seed match-specific targeting of cellular genes, KSHV miRNAs may also function by hijacking RISCs, thereby contributing to a global de-repression of cellular gene expression due to the loss of regulation by human miRNAs. In summary, we provide an extensive list of cellular and viral miRNA targets representing an important

  12. Activated Nrf2 Interacts with Kaposi's Sarcoma-Associated Herpesvirus Latency Protein LANA-1 and Host Protein KAP1 To Mediate Global Lytic Gene Repression

    PubMed Central

    Gjyshi, Olsi; Roy, Arunava; Dutta, Sujoy; Veettil, Mohanan Valiya; Dutta, Dipanjan

    2015-01-01

    ABSTRACT Kaposi's sarcoma-associated herpesvirus (KSHV) is etiologically associated with Kaposi's sarcoma (KS), primary effusion lymphoma (PEL), and multicentric Castleman's disease. We have previously shown that KSHV utilizes the host transcription factor Nrf2 to aid in infection of endothelial cells and oncogenesis. Here, we investigate the role of Nrf2 in PEL and PEL-derived cell lines and show that KSHV latency induces Nrf2 protein levels and transcriptional activity through the COX-2/PGE2/EP4/PKCζ axis. Next-generation sequencing of KSHV transcripts in the PEL-derived BCBL-1 cell line revealed that knockdown of this activated Nrf2 results in global elevation of lytic genes. Nrf2 inhibition by the chemical brusatol also induces lytic gene expression. Both Nrf2 knockdown and brusatol-mediated inhibition induced KSHV lytic reactivation in BCBL-1 cells. In a series of follow-up experiments, we characterized the mechanism of Nrf2-mediated regulation of KSHV lytic repression during latency. Biochemical assays showed that Nrf2 interacted with KSHV latency-associated nuclear antigen 1 (LANA-1) and the host transcriptional repressor KAP1, which together have been shown to repress lytic gene expression. Promoter studies showed that although Nrf2 alone induces the open reading frame 50 (ORF50) promoter, its association with LANA-1 and KAP1 abrogates this effect. Interestingly, LANA-1 is crucial for efficient KAP1/Nrf2 association, while Nrf2 is essential for LANA-1 and KAP1 recruitment to the ORF50 promoter and its repression. Overall, these results suggest that activated Nrf2, LANA-1, and KAP1 assemble on the ORF50 promoter in a temporal fashion. Initially, Nrf2 binds to and activates the ORF50 promoter during early de novo infection, an effect that is exploited during latency by LANA-1-mediated recruitment of the host transcriptional repressor KAP1 on Nrf2. Cell death assays further showed that Nrf2 and KAP1 knockdown induce significant cell death in PEL cell lines

  13. A potential alpha-helix motif in the amino terminus of LANA encoded by Kaposi's sarcoma-associated herpesvirus is critical for nuclear accumulation of HIF-1alpha in normoxia.

    PubMed

    Cai, Qiliang; Murakami, Masanao; Si, Huaxin; Robertson, Erle S

    2007-10-01

    Hypoxia-inducible factor 1 (HIF-1) is a ubiquitously expressed transcriptional regulator involved in induction of numerous genes associated with angiogenesis and tumor growth. Kaposi's sarcoma, associated with increased angiogenesis, is a highly vascularized, endothelial cell-derived tumor. Previously, we have shown that the latency-associated nuclear antigen (LANA) encoded by Kaposi's sarcoma-associated herpesvirus (KSHV) targets the HIF-1alpha suppressors von Hippel-Lindau protein and p53 for degradation via its suppressor of cytokine signaling-box motif, which recruits the EC5S ubiquitin complex. Here we further show that HIF-1alpha was aberrantly accumulated in KSHV latently infected primary effusion lymphoma (PEL) cells, as well as HEK293 cells infected with KSHV, and also show that a potential alpha-helical amino-terminal domain of LANA was important for HIF-1alpha nuclear accumulation in normoxic conditions. Moreover, we have now determined that this association was dependent on the residues 46 to 89 of LANA and the oxygen-dependent degradation domain of HIF-1alpha. Introduction of specific small interfering RNA against LANA into PEL cells also resulted in a diminished nuclear accumulation of HIF-1alpha. Therefore, these data show that LANA can function not only as an inhibitor of HIF-1alpha suppressor proteins but can also induce nuclear accumulation of HIF-1alpha during KSHV latent infection.

  14. Kaposi's sarcoma-associated herpesvirus K3 and K5 ubiquitin E3 ligases have stage-specific immune evasion roles during lytic replication.

    PubMed

    Brulois, Kevin; Toth, Zsolt; Wong, Lai-Yee; Feng, Pinghui; Gao, Shou-Jiang; Ensser, Armin; Jung, Jae U

    2014-08-01

    The downregulation of immune synapse components such as major histocompatibility complex class I (MHC-I) and ICAM-1 is a common viral immune evasion strategy that protects infected cells from targeted elimination by cytolytic effector functions of the immune system. Kaposi's sarcoma-associated herpesvirus (KSHV) encodes two membrane-bound ubiquitin E3 ligases, called K3 and K5, which share the ability to induce internalization and degradation of MHC-I molecules. Although individual functions of K3 and K5 outside the viral genome are well characterized, their roles during the KSHV life cycle are still unclear. In this study, we individually introduced the amino acid-coding sequences of K3 or K5 into a ΔK3 ΔK5 recombinant virus, at either original or interchanged genomic positions. Recombinants harboring coding sequences within the K5 locus showed higher K3 and K5 protein expression levels and more rapid surface receptor downregulation than cognate recombinants in which coding sequences were introduced into the K3 locus. To identify infected cells undergoing K3-mediated downregulation of MHC-I, we employed a novel reporter virus, called red-green-blue-BAC16 (RGB-BAC16), which was engineered to harbor three fluorescent protein expression cassettes: EF1α-monomeric red fluorescent protein 1 (mRFP1), polyadenylated nuclear RNA promoter (pPAN)-enhanced green fluorescent protein (EGFP), and pK8.1-monomeric blue fluorescent protein (tagBFP), marking latent, immediate early, and late viral gene expression, respectively. Analysis of RGB-derived K3 and K5 deletion mutants showed that while the K5-mediated downregulation of MHC-I was concomitant with pPAN induction, the reduction of MHC-I surface expression by K3 was evident in cells that were enriched for pPAN-driven EGFP(high) and pK8.1-driven blue fluorescent protein-positive (BFP(+)) populations. These data support the notion that immunoreceptor downregulation occurs by a sequential process wherein K5 is critical during

  15. Kaposi's Sarcoma-Associated Herpesvirus K3 and K5 Ubiquitin E3 Ligases Have Stage-Specific Immune Evasion Roles during Lytic Replication

    PubMed Central

    Brulois, Kevin; Toth, Zsolt; Wong, Lai-Yee; Feng, Pinghui; Gao, Shou-Jiang; Ensser, Armin

    2014-01-01

    ABSTRACT The downregulation of immune synapse components such as major histocompatibility complex class I (MHC-I) and ICAM-1 is a common viral immune evasion strategy that protects infected cells from targeted elimination by cytolytic effector functions of the immune system. Kaposi's sarcoma-associated herpesvirus (KSHV) encodes two membrane-bound ubiquitin E3 ligases, called K3 and K5, which share the ability to induce internalization and degradation of MHC-I molecules. Although individual functions of K3 and K5 outside the viral genome are well characterized, their roles during the KSHV life cycle are still unclear. In this study, we individually introduced the amino acid-coding sequences of K3 or K5 into a ΔK3 ΔK5 recombinant virus, at either original or interchanged genomic positions. Recombinants harboring coding sequences within the K5 locus showed higher K3 and K5 protein expression levels and more rapid surface receptor downregulation than cognate recombinants in which coding sequences were introduced into the K3 locus. To identify infected cells undergoing K3-mediated downregulation of MHC-I, we employed a novel reporter virus, called red-green-blue-BAC16 (RGB-BAC16), which was engineered to harbor three fluorescent protein expression cassettes: EF1α-monomeric red fluorescent protein 1 (mRFP1), polyadenylated nuclear RNA promoter (pPAN)-enhanced green fluorescent protein (EGFP), and pK8.1-monomeric blue fluorescent protein (tagBFP), marking latent, immediate early, and late viral gene expression, respectively. Analysis of RGB-derived K3 and K5 deletion mutants showed that while the K5-mediated downregulation of MHC-I was concomitant with pPAN induction, the reduction of MHC-I surface expression by K3 was evident in cells that were enriched for pPAN-driven EGFPhigh and pK8.1-driven blue fluorescent protein-positive (BFP+) populations. These data support the notion that immunoreceptor downregulation occurs by a sequential process wherein K5 is critical

  16. Kaposi's sarcoma-associated herpesvirus (human herpesvirus 8) replication and transcription factor activates the K9 (vIRF) gene through two distinct cis elements by a non-DNA-binding mechanism.

    PubMed

    Ueda, Keiji; Ishikawa, Kayo; Nishimura, Ken; Sakakibara, Shuhei; Do, Eunju; Yamanishi, Koichi

    2002-12-01

    The replication and transcription activator (RTA) of Kaposi's sarcoma-associated herpesvirus (KSHV), or human herpesvirus 8, a homologue of Epstein-Barr virus BRLF1 or Rta, is a strong transactivator and inducer of lytic replication. RTA acting alone can induce lytic replication of KSHV in infected cell lines that originated from primary effusion lymphomas, leading to virus production. During the lytic replication process, RTA activates many kinds of genes, including polyadenylated nuclear RNA, K8, K9 (vIRF), ORF57, and so on. We focused here on the mechanism of how RTA upregulates the K9 (vIRF) promoter and identified two independent cis-acting elements in the K9 (vIRF) promoter that responded to RTA. These elements were finally confined to the sequence 5'-TCTGGGACAGTC-3' in responsive element (RE) I-2B and the sequence 5'-GTACTTAAAATA-3' in RE IIC-2, both of which did not share sequence homology. Multiple factors bound specifically with these elements, and their binding was correlated with the RTA-responsive activity. Electrophoretic mobility shift assay with nuclear extract from infected cells and the N-terminal part of RTA expressed in Escherichia coli, however, did not show that RTA interacted directly with these elements, in contrast to the RTA responsive elements in the PAN/K12 promoter region, the ORF57/K8 promoter region. Thus, it was likely that RTA could transactivate several kinds of unique cis elements without directly binding to the responsive elements, probably through cooperation with other DNA-binding factors.

  17. Differences in Kaposi sarcoma-associated herpesvirus-specific and –nonspecific immune responses in classic Kaposi sarcoma cases and matched controls in Sicily

    PubMed Central

    Amodio, Emanuele; Goedert, James J.; Barozzi, Patrizia; Riva, Giovanni; Firenze, Alberto; Bonura, Filippa; Viviano, Enza; Romano, Nino; Luppi, Mario

    2011-01-01

    SUMMARY Kaposi sarcoma (KS) may develop because of incompetent immune responses, both nonspecifically and specifically against the KS-associated herpes virus (KSHV). Peripheral blood mononuclear cells from 15 classic (non-AIDS) KS cases, 13 KSHV seropositives (without KS), and 15 KSHV-seronegative controls were tested for interferon-γ T-cell (Elispot) responses to KSHV-LANA, KSHV-K8.1, and CMV/EBV peptide pools. The forearm and thigh of each participant also was tested for delayed-type hypersensitivity (DTH) against common recall antigens. Groups were compared with Fisher exact test and multinomial logistic regression to calculate odds ratios (OR) and 95% confidence intervals (CI). KSHV Elispot response was detected in 10 (67%) classic KS cases, 11 (85%) KSHV seropositives (without KS), and 2 (13%) seronegative controls. All 4 cases with KSHV-LANA responses had current KS lesions, whereas 5 of 6 cases with KSHV-K8.1 responses had no lesions (P=0.048). No case responded to both LANA and K8.1. Compared to seronegative controls, risk for classic KS was inversely related to DTH in the thigh (OR 0.71, 95% CI 0.55–0.94, P=0.01), directly associated with DTH in the forearm (OR 1.35, 95% CI 1.02–1.80, P=0.04), and tended to be increased 5-fold per KSHV Elispot response (OR 5.13, 95% CI 0.86–30.77, P=0.07). Compared to KSHV seropositives (without KS), risk for classic KS, was reduced 5-fold (OR 0.20, CI 0.03–0.77, P=0.04) per KSHV response. CMV/EBV Elispot responses were irrelevant. Deficiency of both KSHV-specific and –nonspecific immunity is associated with classic KS. This may clarify why Kaposi sarcoma responds to immune reconstitution. PMID:21740480

  18. HIV-1 Vpr Inhibits Kaposi's Sarcoma-Associated Herpesvirus Lytic Replication by Inducing MicroRNA miR-942-5p and Activating NF-κB Signaling

    PubMed Central

    Yan, Qin; Shen, Chenyou; Qin, Jie; Li, Wan; Hu, Minmin; Lu, Hongmei; Qin, Di; Zhu, Jianzhong; Gao, Shou-Jiang

    2016-01-01

    ABSTRACT Kaposi's sarcoma-associated herpesvirus (KSHV) infection is required for the development of several AIDS-related malignancies, including Kaposi's sarcoma (KS) and primary effusion lymphoma (PEL). The high incidence of AIDS-KS has been ascribed to the interaction of KSHV and HIV-1. We have previously shown that HIV-1-secreted proteins Tat and Nef regulate the KSHV life cycle and synergize with KSHV oncogenes to promote angiogenesis and tumorigenesis. Here, we examined the regulation of KSHV latency by HIV-1 viral protein R (Vpr). We found that soluble Vpr inhibits the expression of KSHV lytic transcripts and proteins, as well as viral particle production by activating NF-κB signaling following internalization into PEL cells. By analyzing the expression profiles of microRNAs combined with target search by bioinformatics and luciferase reporter analyses, we identified a Vpr-upregulated cellular microRNA (miRNA), miR-942-5p, that directly targeted IκBα. Suppression of miR-942-5p relieved the expression of IκBα and reduced Vpr inhibition of KSHV lytic replication, while overexpression of miR-942-5p enhanced Vpr inhibition of KSHV lytic replication. Our findings collectively illustrate that, by activating NF-κB signaling through upregulating a cellular miRNA to target IκBα, internalized HIV-1 Vpr inhibits KSHV lytic replication. These results have demonstrated an essential role of Vpr in the life cycle of KSHV. IMPORTANCE Coinfection by HIV-1 promotes the aggressive growth of Kaposi's sarcoma-associated herpesvirus (KSHV)-related malignancies, including Kaposi's sarcoma (KS) and primary effusion lymphoma (PEL). In this study, we have shown that soluble HIV-1 Vpr inhibits KSHV lytic replication by activating NF-κB signaling following internalization into PEL cells. Mechanistic studies revealed that a cellular microRNA upregulated by Vpr, miR-942-5p, directly targeted IκBα. Suppression of miR-942-5p relieved IκBα expression and reduced Vpr inhibition

  19. Kaposi Sarcoma-associated Herpesvirus vIRF-3 Protein Binds to F-box of Skp2 Protein and Acts as a Regulator of c-Myc Protein Function and Stability*

    PubMed Central

    Baresova, Petra; Pitha, Paula M.; Lubyova, Barbora

    2012-01-01

    The Kaposi sarcoma-associated herpesvirus (KSHV) has been linked to Kaposi sarcoma, body cavity-based lymphoma, and Castleman disease. vIRF-3 is a KSHV latent gene that is critical for proliferation of KSHV-positive lymphoid cells. Furthermore, vIRF-3 contributes to KSHV-associated pathogenesis by stimulating c-Myc transcription activity. Here we show that vIRF-3 can associate with Skp2, a key component of the SCFskp2 ubiquitin ligase complex. Skp2 is a transcriptional co-factor for c-Myc that was shown to regulate the stability of c-Myc protein as well as c-Myc-dependent transcription. In this study, we show that vIRF-3 binds to the F-box of Skp2 and recruits it to c-Myc-regulated promoters to activate c-Myc-dependent transcription. Additionally, cells overexpressing vIRF-3 exhibit higher levels of c-Myc ubiquitylation, suggesting that ubiquitylation is necessary for c-Myc-mediated transcription. Moreover, vIRF-3 can stabilize the c-Myc protein by increasing its half-life. Collectively, these results indicate that vIRF-3 can effectively manipulate c-Myc stability and function and thus contribute to c-Myc-induced KSHV-associated lymphomagenesis. PMID:22453922

  20. Lytic Replication of Kaposi's Sarcoma-Associated Herpesvirus Results in the Formation of Multiple Capsid Species: Isolation and Molecular Characterization of A, B, and C Capsids from a Gammaherpesvirus

    PubMed Central

    Nealon, K.; Newcomb, W. W.; Pray, T. R.; Craik, C. S.; Brown, J. C.; Kedes, D. H.

    2001-01-01

    Despite the discovery of Epstein-Barr virus more than 35 years ago, a thorough understanding of gammaherpesvirus capsid composition and structure has remained elusive. We approached this problem by purifying capsids from Kaposi's sarcoma-associated herpesvirus (KSHV), the only other known human gammaherpesvirus. The results from our biochemical and imaging analyses demonstrate that KSHV capsids possess a typical herpesvirus icosahedral capsid shell composed of four structural proteins. The hexameric and pentameric capsomers are composed of the major capsid protein (MCP) encoded by open reading frame 25. The heterotrimeric complexes, forming the capsid floor between the hexons and pentons, are each composed of one molecule of ORF62 and two molecules of ORF26. Each of these proteins has significant amino acid sequence homology to capsid proteins in alpha- and betaherpesviruses. In contrast, the fourth protein, ORF65, lacks significant sequence homology to its structural counterparts from the other subfamilies. Nevertheless, this small, basic, and highly antigenic protein decorates the surface of the capsids, as does, for example, the even smaller basic capsid protein VP26 of herpes simplex virus type 1. We have also found that, as with the alpha- and betaherpesviruses, lytic replication of KSHV leads to the formation of at least three capsid species, A, B, and C, with masses of approximately 200, 230, and 300 MDa, respectively. A capsids are empty, B capsids contain an inner array of a fifth structural protein, ORF17.5, and C capsids contain the viral genome. PMID:11222712

  1. Kaposi's sarcoma-associated herpesvirus Rta tetramers make high-affinity interactions with repetitive DNA elements in the Mta promoter to stimulate DNA binding of RBP-Jk/CSL.

    PubMed

    Palmeri, Diana; Carroll, Kyla Driscoll; Gonzalez-Lopez, Olga; Lukac, David M

    2011-11-01

    Kaposi's sarcoma-associated herpesvirus (KSHV; also known as human herpesvirus 8 [HHV-8]) is the etiologic agent of Kaposi's sarcoma (KS) and lymphoproliferative diseases. We previously demonstrated that the KSHV lytic switch protein Rta stimulates DNA binding of the cellular RBP-Jk/CSL protein, the nuclear component of the Notch pathway, on Rta target promoters. In the current study, we define the promoter requirements for formation of transcriptionally productive Rta/RBP-Jk/DNA complexes. We show that highly pure Rta footprints 7 copies of a previously undescribed repetitive element in the promoter of the essential KSHV Mta gene. We have termed this element the "CANT repeat." CANT repeats are found on both strands of DNA and have a consensus sequence of ANTGTAACANT(A/T)(A/T)T. We demonstrate that Rta tetramers make high-affinity interactions (i.e., nM) with 64 bp of the Mta promoter but not single CANT units. The number of CANT repeats, their presence in palindromes, and their positions relative to the RBP-Jk binding site determine the optimal target for Rta stimulation of RBP-Jk DNA binding and formation of ternary Rta/RBP-Jk/DNA complexes. DNA binding and tetramerization mutants of Rta fail to stimulate RBP-Jk DNA binding. Our chromatin immunoprecipitation assays show that RBP-Jk DNA binding is broadly, but selectively, stimulated across the entire KSHV genome during reactivation. We propose a model in which tetramerization of Rta allows it to straddle RBP-Jk and contact repeat units on both sides of RBP-Jk. Our study integrates high-affinity Rta DNA binding with the requirement for a cellular transcription factor in Rta transactivation.

  2. The specificities of Kaposi's sarcoma-associated herpesvirus-encoded E3 ubiquitin ligases are determined by the positions of lysine or cysteine residues within the intracytoplasmic domains of their targets.

    PubMed

    Cadwell, Ken; Coscoy, Laurent

    2008-04-01

    Kaposi's sarcoma-associated herpesvirus encodes two homologous E3 ligases, MIR1 and MIR2, that mediate the ubiquitination and subsequent downregulation of several cell surface proteins, and in particular major histocompatibility complex class I (MHC-I) molecules. We have previously shown that, in addition to lysine ubiquitination, MIR1 has the unique ability of transferring ubiquitin onto MHC-I molecules lacking available lysine residues, in a cysteine-dependent manner. Here we report that MIR1 activity is maximal when either a lysine or cysteine residue is placed approximately 15 amino acids away from the transmembrane domain, whereas MIR2 preferentially targets residues, including cysteines, that are closer to the transmembrane domain. Thus MIR1 and -2 can distinguish their substrates based on the position of the lysine or cysteine residues, suggesting that these proteins have evolved to target different sets of surface molecules. These results indicate that the position of target residues within a substrate is an essential determinant of E3 ubiquitin ligase specificity.

  3. Making sense of antisense: seemingly noncoding RNAs antisense to the master regulator of Kaposi's sarcoma-associated herpesvirus lytic replication do not regulate that transcript but serve as mRNAs encoding small peptides.

    PubMed

    Xu, Yiyang; Ganem, Don

    2010-06-01

    The mammalian transcriptome is studded with putative noncoding RNAs, many of which are antisense to known open reading frames (ORFs). Roles in the regulation of their complementary mRNAs are often imputed to these antisense transcripts, but few have been experimentally examined, and such functions remain largely conjectural. Kaposi's sarcoma-associated herpesvirus (KSHV) encodes two transcripts that lack obvious ORFs and are complementary to the gene (RTA) encoding the master regulator of the latent/lytic switch. Here, we show that, contrary to expectation, these RNAs do not regulate RTA expression. Rather, they are found on polysomes, and genetic analysis indicates that translational initiation occurs at several AUG codons in the RNA, leading to the presumptive synthesis of peptides of 17 to 48 amino acids. These findings underscore the need for circumspection in the computational assessment of coding potential and raise the possibility that the mammalian proteome may contain many previously unsuspected peptides generated from seemingly noncoding RNAs, some of which could have important biological functions. Irrespective of their function, such peptides could also contribute substantially to the repertoire of T cell epitopes generated in both uninfected and infected cells.

  4. A survey of the interactome of Kaposi's sarcoma-associated herpesvirus ORF45 revealed its binding to viral ORF33 and cellular USP7, resulting in stabilization of ORF33 that is required for production of progeny viruses.

    PubMed

    Gillen, Joseph; Li, Wenwei; Liang, Qiming; Avey, Denis; Wu, Jianjun; Wu, Fayi; Myoung, JinJong; Zhu, Fanxiu

    2015-05-01

    The ORF45 protein of Kaposi's sarcoma-associated herpesvirus (KSHV) is a gammaherpesvirus-specific immediate-early tegument protein. Our previous studies have revealed its crucial roles in both early and late stages of KSHV infection. In this study, we surveyed the interactome of ORF45 using a panel of monoclonal antibodies. In addition to the previously identified extracellular regulated kinase (ERK) and p90 ribosomal S6 kinase (RSK) proteins, we found several other copurified proteins, including prominent ones of ∼38 kDa and ∼130 kDa. Mass spectrometry revealed that the 38-kDa protein is viral ORF33 and the 130-kDa protein is cellular USP7 (ubiquitin-specific protease 7). We mapped the ORF33-binding domain to the highly conserved carboxyl-terminal 19 amino acids (aa) of ORF45 and the USP7-binding domain to the reported consensus motif in the central region of ORF45. Using immunofluorescence staining, we observed colocalization of ORF45 with ORF33 or USP7 both under transfected conditions and in KSHV-infected cells. Moreover, we noticed ORF45-dependent relocalization of a portion of ORF33/USP7 from the nucleus to the cytoplasm. We found that ORF45 caused an increase in ORF33 protein accumulation that was abolished if either the ORF33- or USP7-binding domain in ORF45 was deleted. Furthermore, deletion of the conserved carboxyl terminus of ORF45 in the KSHV genome drastically reduced the level of ORF33 protein in KSHV-infected cells and abolished production of progeny virions. Collectively, our results not only reveal new components of the ORF45 interactome, but also demonstrate that the interactions among these proteins are crucial for KSHV lytic replication. Kaposi's sarcoma-associated herpesvirus (KSHV) is the causative agent of several human cancers. KSHV ORF45 is a multifunctional protein that is required for KSHV lytic replication, but the exact mechanisms by which ORF45 performs its critical functions are unclear. Our previous studies revealed that all

  5. A Survey of the Interactome of Kaposi's Sarcoma-Associated Herpesvirus ORF45 Revealed Its Binding to Viral ORF33 and Cellular USP7, Resulting in Stabilization of ORF33 That Is Required for Production of Progeny Viruses

    PubMed Central

    Gillen, Joseph; Li, Wenwei; Liang, Qiming; Avey, Denis; Wu, Jianjun; Wu, Fayi; Myoung, JinJong

    2015-01-01

    ABSTRACT The ORF45 protein of Kaposi's sarcoma-associated herpesvirus (KSHV) is a gammaherpesvirus-specific immediate-early tegument protein. Our previous studies have revealed its crucial roles in both early and late stages of KSHV infection. In this study, we surveyed the interactome of ORF45 using a panel of monoclonal antibodies. In addition to the previously identified extracellular regulated kinase (ERK) and p90 ribosomal S6 kinase (RSK) proteins, we found several other copurified proteins, including prominent ones of ∼38 kDa and ∼130 kDa. Mass spectrometry revealed that the 38-kDa protein is viral ORF33 and the 130-kDa protein is cellular USP7 (ubiquitin-specific protease 7). We mapped the ORF33-binding domain to the highly conserved carboxyl-terminal 19 amino acids (aa) of ORF45 and the USP7-binding domain to the reported consensus motif in the central region of ORF45. Using immunofluorescence staining, we observed colocalization of ORF45 with ORF33 or USP7 both under transfected conditions and in KSHV-infected cells. Moreover, we noticed ORF45-dependent relocalization of a portion of ORF33/USP7 from the nucleus to the cytoplasm. We found that ORF45 caused an increase in ORF33 protein accumulation that was abolished if either the ORF33- or USP7-binding domain in ORF45 was deleted. Furthermore, deletion of the conserved carboxyl terminus of ORF45 in the KSHV genome drastically reduced the level of ORF33 protein in KSHV-infected cells and abolished production of progeny virions. Collectively, our results not only reveal new components of the ORF45 interactome, but also demonstrate that the interactions among these proteins are crucial for KSHV lytic replication. IMPORTANCE Kaposi's sarcoma-associated herpesvirus (KSHV) is the causative agent of several human cancers. KSHV ORF45 is a multifunctional protein that is required for KSHV lytic replication, but the exact mechanisms by which ORF45 performs its critical functions are unclear. Our previous studies

  6. Kaposi's Sarcoma-Associated Herpesvirus Latency-Associated Nuclear Antigen Inhibits Major Histocompatibility Complex Class II Expression by Disrupting Enhanceosome Assembly through Binding with the Regulatory Factor X Complex

    PubMed Central

    Thakker, Suhani; Purushothaman, Pravinkumar; Gupta, Namrata; Challa, Shanthan; Cai, Qiliang

    2015-01-01

    ABSTRACT Major histocompatibility complex class II (MHC-II) molecules play a central role in adaptive antiviral immunity by presenting viral peptides to CD4+ T cells. Due to their key role in adaptive immunity, many viruses, including Kaposi's sarcoma-associated herpesvirus (KSHV), have evolved multiple strategies to inhibit the MHC-II antigen presentation pathway. The expression of MHC-II, which is controlled mainly at the level of transcription, is strictly dependent upon the binding of the class II transactivator (CIITA) to the highly conserved promoters of all MHC-II genes. The recruitment of CIITA to MHC-II promoters requires its direct interactions with a preassembled MHC-II enhanceosome consisting of cyclic AMP response element-binding protein (CREB) and nuclear factor Y (NF-Y) complex and regulatory factor X (RFX) complex proteins. Here, we show that KSHV-encoded latency-associated nuclear antigen (LANA) disrupts the association of CIITA with the MHC-II enhanceosome by binding to the components of the RFX complex. Our data show that LANA is capable of binding to all three components of the RFX complex, RFX-associated protein (RFXAP), RFX5, and RFX-associated ankyrin-containing protein (RFXANK), in vivo but binds more strongly with the RFXAP component in in vitro binding assays. Levels of MHC-II proteins were significantly reduced in KSHV-infected as well as LANA-expressing B cells. Additionally, the expression of LANA in a luciferase promoter reporter assay showed reduced HLA-DRA promoter activity in a dose-dependent manner. Chromatin immunoprecipitation assays showed that LANA binds to the MHC-II promoter along with RFX proteins and that the overexpression of LANA disrupts the association of CIITA with the MHC-II promoter. These assays led to the conclusion that the interaction of LANA with RFX proteins interferes with the recruitment of CIITA to MHC-II promoters, resulting in an inhibition of MHC-II gene expression. Thus, the data presented here identify

  7. Kaposi sarcoma herpesvirus pathogenesis

    PubMed Central

    Koch, Sandra; Schulz, Thomas F.

    2017-01-01

    Kaposi sarcoma herpesvirus (KSHV), taxonomical name human gammaherpesvirus 8, is a phylogenetically old human virus that co-evolved with human populations, but is now only common (seroprevalence greater than 10%) in sub-Saharan Africa, around the Mediterranean Sea, parts of South America and in a few ethnic communities. KSHV causes three human malignancies, Kaposi sarcoma, primary effusion lymphoma, and many cases of the plasmablastic form of multicentric Castleman's disease (MCD) as well as occasional cases of plasmablastic lymphoma arising from MCD; it has also been linked to rare cases of bone marrow failure and hepatitis. As it has colonized humans physiologically for many thousand years, cofactors are needed to allow it to unfold its pathogenic potential. In most cases, these include immune defects of genetic, iatrogenic or infectious origin, and inflammation appears to play an important role in disease development. Our much improved understanding of its life cycle and its role in pathogenesis should now allow us to develop new therapeutic strategies directed against key viral proteins or intracellular pathways that are crucial for virus replication or persistence. Likewise, its limited (for a herpesvirus) distribution and transmission should offer an opportunity for the development and use of a vaccine to prevent transmission. This article is part of the themed issue ‘Human oncogenic viruses’. PMID:28893942

  8. The central repeat domain 1 of Kaposi's sarcoma-associated herpesvirus (KSHV) latency associated-nuclear antigen 1 (LANA1) prevents cis MHC class I peptide presentation

    SciTech Connect

    Kwun, Hyun Jin; Ramos da Silva, Suzane; Qin Huilian; Ferris, Robert L.; Tan Rusung; Chang Yuan; Moore, Patrick S.

    2011-04-10

    KSHV LANA1, a latent protein expressed during chronic infection to maintain a viral genome, inhibits major histocompatibility complex class I (MHC I) peptide presentation in cis as a means of immune evasion. Through deletional cloning, we localized this function to the LANA1 central repeat 1 (CR1) subregion. Other CR subregions retard LANA1 translation and proteasomal processing but do not markedly inhibit LANA1 peptide processing by MHC I. Inhibition of proteasomal processing ablates LANA1 peptide presentation. Direct expression of LANA1 within the endoplasmic reticulum (ER) overcomes CR1 inhibition suggesting that CR1 acts prior to translocation of cytoplasmic peptides into the ER. By physically separating CR1 from other subdomains, we show that LANA1 evades MHC I peptide processing by a mechanism distinct from other herpesviruses including Epstein-Barr virus (EBV). Although LANA1 and EBV EBNA1 are functionally similar, they appear to use different mechanisms to evade host cytotoxic T lymphocyte surveillance.

  9. De novo protein synthesis is required for lytic cycle reactivation of Epstein-Barr virus, but not Kaposi's sarcoma-associated herpesvirus, in response to histone deacetylase inhibitors and protein kinase C agonists.

    PubMed

    Ye, Jianjiang; Gradoville, Lyndle; Daigle, Derek; Miller, George

    2007-09-01

    The oncogenic human gammaherpesviruses, Epstein-Barr virus (EBV) and Kaposi's sarcoma-associated herpesvirus (KSHV), are latent in cultured lymphoma cells. We asked whether reactivation from latency of either virus requires de novo protein synthesis. Using Northern blotting and quantitative reverse transcriptase PCR, we measured the kinetics of expression of the lytic cycle activator genes and determined whether abundance of mRNAs encoding these genes from either virus was reduced by treatment with cycloheximide (CHX), an inhibitor of protein synthesis. CHX blocked expression of mRNAs of EBV BZLF1 and BRLF1, the two EBV lytic cycle activator genes, when HH514-16 Burkitt lymphoma cells were treated with histone deacetylase (HDAC) inhibitors, sodium butyrate or trichostatin A, or a DNA methyltransferase inhibitor, 5-Aza-2'-deoxycytidine. CHX also inhibited EBV lytic cycle activation in B95-8 marmoset lymphoblastoid cells by phorbol ester phorbol-12-myristate-13-acetate (TPA). EBV lytic cycle induction became resistant to CHX between 4 and 6 h after application of the inducing stimulus. KSHV lytic cycle activation, as assessed by ORF50 mRNA expression, was rapidly induced by the HDAC inhibitors, sodium butyrate and trichostatin A, in HH-B2 primary effusion lymphoma cells. In HH-B2 cells, CHX did not inhibit, but enhanced, expression of the KSHV lytic cycle activator gene, ORF50. In BC-1, a primary effusion lymphoma cell line that is dually infected with EBV and KSHV, CHX blocked EBV BRLF1 lytic gene expression induced by TPA and sodium butyrate; KSHV ORF50 mRNA induced simultaneously in the same cells by the same inducing stimuli was resistant to CHX. The experiments show, for the cell lines and inducing agents studied, that the EBV BZLF1 and BRLF1 genes do not behave with "immediate-early" kinetics upon reactivation from latency. KSHV ORF50 is a true "immediate-early" gene. Our results indicate that the mechanism by which HDAC inhibitors and TPA induce lytic cycle

  10. Kaposi's Sarcoma-Associated Herpesvirus (KSHV) Induces the Oncogenic miR-17-92 Cluster and Down-Regulates TGF-β Signaling.

    PubMed

    Choi, Hong Seok; Jain, Vaibhav; Krueger, Brian; Marshall, Vickie; Kim, Chang Hee; Shisler, Joanna L; Whitby, Denise; Renne, Rolf

    2015-01-01

    KSHV is a DNA tumor virus that causes Kaposi's sarcoma. Upon KSHV infection, only a limited number of latent genes are expressed. We know that KSHV infection regulates host gene expression, and hypothesized that latent genes also modulate the expression of host miRNAs. Aberrant miRNA expression contributes to the development of many types of cancer. Array-based miRNA profiling revealed that all six miRNAs of the oncogenic miR-17-92 cluster are up-regulated in KSHV infected endothelial cells. Among candidate KSHV latent genes, we found that vFLIP and vCyclin were shown to activate the miR-17-92 promoter, using luciferase assay and western blot analysis. The miR-17-92 cluster was previously shown to target TGF-β signaling. We demonstrate that vFLIP and vCyclin induce the expression of the miR-17-92 cluster to strongly inhibit the TGF-β signaling pathway by down-regulating SMAD2. Moreover, TGF-β activity and SMAD2 expression were fully restored when antagomirs (inhibitors) of miR-17-92 cluster were transfected into cells expressing either vFLIP or vCyclin. In addition, we utilized viral genetics to produce vFLIP or vCyclin knock-out viruses, and studied the effects in infected TIVE cells. Infection with wildtype KSHV abolished expression of SMAD2 protein in these endothelial cells. While single-knockout mutants still showed a marked reduction in SMAD2 expression, TIVE cells infected by a double-knockout mutant virus were fully restored for SMAD2 expression, compared to non-infected TIVE cells. Expression of either vFLIP or vCycIin was sufficient to downregulate SMAD2. In summary, our data demonstrate that vFLIP and vCyclin induce the oncogenic miR-17-92 cluster in endothelial cells and thereby interfere with the TGF-β signaling pathway. Manipulation of the TGF-β pathway via host miRNAs represents a novel mechanism that may be important for KSHV tumorigenesis and angiogenesis, a hallmark of KS.

  11. Constitutive activation of NF-kappa B and secretion of interleukin-8 induced by the G protein-coupled receptor of Kaposi's sarcoma-associated herpesvirus involve G alpha(13) and RhoA.

    PubMed

    Shepard, L W; Yang, M; Xie, P; Browning, D D; Voyno-Yasenetskaya, T; Kozasa, T; Ye, R D

    2001-12-07

    The Kaposi's sarcoma herpesvirus (KSHV) open reading frame 74 encodes a G protein-coupled receptor (GPCR) for chemokines. Exogenous expression of this constitutively active GPCR leads to cell transformation and vascular overgrowth characteristic of Kaposi's sarcoma. We show here that expression of KSHV-GPCR in transfected cells results in constitutive transactivation of nuclear factor kappa B (NF-kappa B) and secretion of interleukin-8, and this response involves activation of G alpha(13) and RhoA. The induced expression of a NF-kappa B luciferase reporter was partially reduced by pertussis toxin and the G beta gamma scavenger transducin, and enhanced by co-expression of G alpha(13) and to a lesser extent, G alpha(q). These results indicate coupling of KSHV-GPCR to multiple G proteins for NF-kappa B activation. Expression of KSHV-GPCR led to stress fiber formation in NIH 3T3 cells. To examine the involvement of the G alpha(13)-RhoA pathway in KSHV-GPCR-mediated NF-kappa B activation, HeLa cells were transfected with KSHV-GPCR alone and in combination with the regulator of G protein signaling (RGS) from p115RhoGEF or a dominant negative RhoA(T19N). Both constructs, as well as the C3 exoenzyme from Clostritium botulinum, partially reduced NF-kappa B activation by KSHV-GPCR, and by a constitutively active G alpha(13)(Q226L). KSHV-GPCR-induced NF-kappa B activation is accompanied by increased secretion of IL-8, a function mimicked by the activated G alpha(13) but not by an activated G alpha(q)(Q209L). These results suggest coupling of KSHV-GPCR to the G alpha(13)-RhoA pathway in addition to other G proteins.

  12. Kaposi's sarcoma-associated herpesvirus microRNAs target IRAK1 and MYD88, two components of the toll-like receptor/interleukin-1R signaling cascade, to reduce inflammatory-cytokine expression.

    PubMed

    Abend, Johanna R; Ramalingam, Dhivya; Kieffer-Kwon, Philippe; Uldrick, Thomas S; Yarchoan, Robert; Ziegelbauer, Joseph M

    2012-11-01

    Kaposi's sarcoma (KS)-associated herpesvirus (KSHV) is the causative agent of KS, an important AIDS-associated malignancy. KSHV expresses at least 18 different mature microRNAs (miRNAs). We identified interleukin-1 receptor (IL-1R)-associated kinase 1 (IRAK1) as a potential target of miR-K12-9 (miR-K9) in an array data set examining changes in cellular gene expression levels in the presence of KSHV miRNAs. Using 3'-untranslated region (3'UTR) luciferase reporter assays, we confirmed that miR-K9 and other miRNAs inhibit IRAK1 expression. In addition, IRAK1 expression is downregulated in cells transfected with miR-K9 and during de novo KSHV infection. IRAK1 is an important component of the Toll-like receptor (TLR)/IL-1R signaling cascade. The downregulation of IRAK1 by miR-K9 resulted in the decreased stimulation of NF-κB activity in endothelial cells treated with IL-1α and in B cells treated with a TLR7/8 agonist. Interestingly, miR-K9 had a greater effect on NF-κB activity than did a small interfering RNA (siRNA) targeting IRAK1 despite the more efficient downregulation of IRAK1 expression with the siRNA. We hypothesized that KSHV miRNAs may also be regulating a second component of the TLR/IL-1R signaling cascade, resulting in a stronger phenotype. Reanalysis of the array data set identified myeloid differentiation primary response protein 88 (MYD88) as an additional potential target. 3'UTR luciferase reporter assays and Western blot analysis confirmed the targeting of MYD88 by miR-K5. The presence of miR-K9 and miR-K5 inhibited the production of IL-6 and IL-8 upon the IL-1α stimulation of endothelial cells. These results demonstrate KSHV-encoded miRNAs regulating the TLR/IL-1R signaling cascade at two distinct points and suggest the importance of these pathways during viral infection.

  13. High-level variability in the ORF-K1 membrane protein gene at the left end of the Kaposi's sarcoma-associated herpesvirus genome defines four major virus subtypes and multiple variants or clades in different human populations.

    PubMed

    Zong, J C; Ciufo, D M; Alcendor, D J; Wan, X; Nicholas, J; Browning, P J; Rady, P L; Tyring, S K; Orenstein, J M; Rabkin, C S; Su, I J; Powell, K F; Croxson, M; Foreman, K E; Nickoloff, B J; Alkan, S; Hayward, G S

    1999-05-01

    Infection with Kaposi's sarcoma (KS)-associated herpesvirus (KSHV) or human herpesvirus 8 (HHV8) is common in certain parts of Africa, the Middle East, and the Mediterranean, but is rare elsewhere, except in AIDS patients. Nevertheless, HHV8 DNA is found consistently in nearly all classical, endemic, transplant and AIDS-associated KS lesions as well as in some rare AIDS-associated lymphomas. The concept that HHV8 genomes fall into several distinct subgroups has been confirmed and refined by PCR DNA sequence analysis of the ORF-K1 gene encoding a highly variable glycoprotein related to the immunoglobulin receptor family that maps at the extreme left-hand end of the HHV-8 genome. Among more than 60 different tumor samples from the United States, central Africa, Saudi Arabia, Taiwan, and New Zealand, amino acid substitutions were found at a total of 62% of the 289 amino acid positions. These variations defined four major subtypes and 13 distinct variants or clades similar to those found for the HIV ENV protein. The B and D subtype ORF-K1 proteins differ from the A and C subtypes by 30 and 24%, respectively, whereas A and C differ from each other by 15%. In all cases tested, multiple samples from the same patient were identical. Examples of the B subtype were found almost exclusively in KS patients from Africa or of African heritage, whereas the rare D subtypes were found only in KS patients of Pacific Island heritage. In contrast, C subtypes were found predominantly in classic KS and in iatrogenic and AIDS KS in the Middle East and Asia, whereas U.S. AIDS KS samples were primarily A1, A4, and C3 variants. We conclude that this unusually high diversity, in which 85% of the nucleotide changes lead to amino acid changes, reflects some unknown powerful biological selection process that has been acting preferentially on this early lytic cycle membrane signalling protein. Two distinct levels of ORF-K1 variability are recognizable. Subtype-specific variability indicative of

  14. Kaposi's Sarcoma Associated-Herpes Virus (KSHV) Seroprevalence in Pregnant Women in South Africa

    PubMed Central

    2010-01-01

    Background Factors previously associated with Kaposi's sarcoma-associated herpesvirus (KSHV) transmission in Africa include sexual, familial, and proximity to river water. We measured the seroprevalence of KSHV in relation to HIV, syphilis, and demographic factors among pregnant women attending public antenatal clinics in the Gauteng province of South Africa. Methods We tested for antibodies to KSHV lytic K8.1 and latent Orf73 antigens in 1740 pregnant women attending antenatal clinics who contributed blood to the "National HIV and Syphilis Sero-Prevalence Survey - South Africa, 2001". Information on HIV and syphilis serology, age, education, residential area, gravidity, and parity was anonymously linked to evaluate risk factors for KSHV seropositivity. Clinics were grouped by municipality regions and their proximity to the two main river catchments defined. Results KSHV seropositivity (reactive to either lytic K8.1 and latent Orf73) was nearly twice that of HIV (44.6% vs. 23.1%). HIV and syphilis seropositivity was 12.7% and 14.9% in women without KSHV, and 36.1% and 19.9% respectively in those with KSHV. Women who are KSHV seropositive were 4 times more likely to be HIV positive than those who were KSHV seronegative (AOR 4.1 95%CI: 3.4 - 5.7). Although, women with HIV infection were more likely to be syphilis seropositive (AOR 1.8 95%CI: 1.3 - 2.4), no association between KSHV and syphilis seropositivity was observed. Those with higher levels of education had lower levels of KSHV seropositivity compared to those with lower education levels. KSHV seropositivity showed a heterogeneous pattern of prevalence in some localities. Conclusions The association between KSHV and HIV seropositivity and a lack of common association with syphilis, suggests that KSHV transmission may involve geographical and cultural factors other than sexual transmission. PMID:20807396

  15. Restoration of immune surface molecules in Kaposi sarcoma-associated herpes virus infected cells by lenalidomide and pomalidomide.

    PubMed

    Davis, David A; Mishra, Suraj; Anagho, Holda A; Aisabor, Ashley I; Shrestha, Prabha; Wang, Victoria; Takamatsu, Yuki; Maeda, Kenji; Mitsuya, Hiroaki; Zeldis, Jerome B; Yarchoan, Robert

    2017-08-01

    Kaposi sarcoma-associated herpesvirus (KSHV) is the cause of several tumors, including Kaposi sarcoma and primary effusion lymphoma (PEL). Most viruses have evolved means of escaping immune recognition. KSHV downregulates MHC-I expression during lytic infection, and expression of ICAM-1 and B7-2 (CD86) during latent infection, allowing evasion of T cell and natural killer immunity respectively. These effects are largely mediated by two KSHV-encoded proteins, K3 and K5. We show here that lenalidomide (Len) and pomalidomide (Pom) prevent down-regulation of MHC-I during lytic activation, and restore ICAM-1 and B7-2 surface expression in latently infected PEL cells. Importantly, these changes occurred at clinically achievable concentrations and prior to any cytotoxic effects. Exploration of the mechanism revealed that Pom blocked lytic down-regulation of MHC-I induced by transfection with K3 but not K5. Although Pom alone did not significantly increase HLA mRNA expression in PEL cells, it did blunt the butyrate-induced decrease in MHC-I mRNA expression and decreased the upregulation of K3 mRNA in lytic cells. Virus-induced tumors express foreign antigens, but immunotherapy can be thwarted by viral strategies to evade immune recognition. The effects of Pom and Len described here can prevent these strategies and support the use of these drugs to treat KSHV-induced tumors.

  16. BALB/c mice immunized with a combination of virus-like particles incorporating Kaposi sarcoma-associated herpesvirus (KSHV) envelope glycoproteins gpK8.1, gB, and gH/gL induced comparable serum neutralizing antibody activity to UV-inactivated KSHV.

    PubMed

    Barasa, Anne K; Ye, Peng; Phelps, Meredith; Arivudainambi, Ganapathiram T; Tison, Timelia; Ogembo, Javier Gordon

    2017-05-23

    Infection with Kaposi sarcoma-associated herpesvirus (KSHV) is estimated to account for over 44,000 new cases of Kaposi sarcoma annually, with 84% occurring in Africa, where the virus is endemic. To date, there is no prophylactic vaccine against KSHV. KSHV gpK8.1, gB, and gH/gL glycoproteins, implicated in the virus entry into host cells, are attractive vaccine targets for eliciting potent neutralizing antibodies (nAbs) against virus infection. We incorporated gpK8.1, gB, or gH/gL on the surface of virus-like particles (VLPs) and characterized these VLPs for their composition, size, and functionality. To determine which viral glycoprotein(s) elicit the most effective serum-nAbs, we immunized BALB/c mice with gpK8.1, gB, or gH/gL VLPs individually or in combination. Neutralizing antibody assay revealed that sera from mice immunized with the VLPs inhibited KSHV infection of HEK-293 cells in a dose-dependent manner. As a single immunogen, gpK8.1 VLPs stimulated comparable nAb activity to that of UV-inactivated KSHV (UV-KSHV). In contrast, UV-KSHV stimulated higher titers of nAb compared to gB (p = 0.0316) or gH/gL (p = 0.0486). Mice immunized with the combination of gB and gH/gL VLPs had a better nAb response than those immunized with either gB (p = 0.0268), or gH/gL (p = 0.0397) as single VLP immunogens. Immunization with any VLP combination stimulated comparable nAb activity to UV-KSHV serum. Our data provide the first evidence that KSHV gpK8.1, gB, and gH/gL glycoproteins can be incorporated onto the surface of VLPs and used as prophylactic vaccine candidates, with potential to prevent KSHV infection.

  17. Association between malaria exposure and Kaposi's sarcoma-associated herpes virus seropositivity in Uganda

    PubMed Central

    Nalwoga, Angela; Cose, Stephen; Wakeham, Katie; Miley, Wendell; Ndibazza, Juliet; Drakeley, Christopher; Elliott, Alison; Whitby, Denise; Newton, Robert

    2015-01-01

    Objective Unlike other herpes viruses, Kaposi's sarcoma-associated herpes virus (KSHV) is not ubiquitous worldwide and is most prevalent in sub-Saharan Africa. The reasons for this are unclear. As part of a wider investigation of factors that facilitate transmission in Uganda, a high prevalence country, we examined the association between antimalaria antibodies and seropositivity against KSHV. Methods Antibodies against P. falciparum merozoite surface protein (PfMSP)-1, P. falciparum apical membrane antigen (PfAMA)-1 and KSHV antigens (ORF73 and K8.1) were measured in samples from 1164 mothers and 1227 children. Results Kaposi's sarcoma-associated herpes virus seroprevalence was 69% among mothers and 15% children. Among mothers, KSHV seroprevalence increased with malaria antibody titres: from 60% to 82% and from 54% to 77%, comparing those with the lowest and highest titres for PfMSP-1 and PfAMA-1, respectively (P < 0.0001). Among children, only antibodies to PfAMA-1 were significantly associated with KSHV seropositivity, (P < 0.0001). In both mothers and children, anti-ORF73 antibodies were more strongly associated with malaria antibodies than anti-K8.1 antibodies. Conclusion The association between malaria exposure and KSHV seropositivity suggests that malaria is a cofactor for KSHV infection or reactivation. PMID:25611008

  18. Activation of DNA Damage Response Induced by the Kaposi's Sarcoma-Associated Herpes Virus.

    PubMed

    Di Domenico, Enea Gino; Toma, Luigi; Bordignon, Valentina; Trento, Elisabetta; D'Agosto, Giovanna; Cordiali-Fei, Paola; Ensoli, Fabrizio

    2016-06-01

    The human herpes virus 8 (HHV-8), also known as Kaposi sarcoma-associated herpes virus (KSHV), can infect endothelial cells often leading to cell transformation and to the development of tumors, namely Kaposi's sarcoma (KS), primary effusion lymphoma (PEL), and the plasmablastic variant of multicentric Castleman's disease. KSHV is prevalent in areas such as sub-Saharan Africa and the Mediterranean region presenting distinct genotypes, which appear to be associated with differences in disease manifestation, according to geographical areas. In infected cells, KSHV persists in a latent episomal form. However, in a limited number of cells, it undergoes spontaneous lytic reactivation to ensure the production of new virions. During both the latent and the lytic cycle, KSHV is programmed to express genes which selectively modulate the DNA damage response (DDR) through the activation of the ataxia telangiectasia mutated (ATM) pathway and by phosphorylating factors associated with the DDR, including the major tumor suppressor protein p53 tumor suppressor p53. This review will focus on the interplay between the KSHV and the DDR response pathway throughout the viral lifecycle, exploring the putative molecular mechanism/s that may contribute to malignant transformation of host cells.

  19. A viral gene that activates lytic cycle expression of Kaposi’s sarcoma-associated herpesvirus

    PubMed Central

    Sun, Ren; Lin, Su-Fang; Gradoville, Lyndle; Yuan, Yan; Zhu, Fanxiu; Miller, George

    1998-01-01

    Herpesviruses exist in two states, latency and a lytic productive cycle. Here we identify an immediate-early gene encoded by Kaposi’s sarcoma-associated herpesvirus (KSHV)/human herpesvirus eight (HHV8) that activates lytic cycle gene expression from the latent viral genome. The gene is a homologue of Rta, a transcriptional activator encoded by Epstein–Barr virus (EBV). KSHV/Rta activated KSHV early lytic genes, including virus-encoded interleukin 6 and polyadenylated nuclear RNA, and a late gene, small viral capsid antigen. In cells dually infected with Epstein–Barr virus and KSHV, each Rta activated only autologous lytic cycle genes. Expression of viral cytokines under control of the KSHV/Rta gene is likely to contribute to the pathogenesis of KSHV-associated diseases. PMID:9724796

  20. Genipin Enhances Kaposi’s Sarcoma-Associated Herpesvirus Genome Maintenance

    PubMed Central

    Son, Kuwon; Park, Gyu Hwan; Jung, Jong-Wha; Shin, Yu Su; Seo, Taegun; Hyosun Cho; Kang, Hyojeung

    2016-01-01

    Kaposi's sarcoma-associated herpesvirus (KSHV) is a Gammaherpesvirus that causes acute infection and establishes life-long latency. KSHV causes several human cancers, including Kaposi's sarcoma, an acquired immune deficiency syndrome (AIDS)-related form of non-Hodgkin lymphoma. Genipin, an aglycone derived from geniposide found in Gardenia jasminoides, is known to be an excellent natural cross-linker, strong apoptosis inducer, and antiviral agent. Although evidence suggests antiviral activity of genipin in several in vitro viral infection systems, no inhibitory effect of genipin on KSHV infection has been reported. Thus, our aim was to determine, using the iSLK-BAC16 KSHV infection system, whether genipin has inhibitory effects on KSHV infection. For this purpose, we evaluated biological effects of genipin on KSHV infection and finally determined the underlying mechanisms responsible for the bioactive effects of genipin. A cytotoxicity assay revealed that genipin caused 50% cytotoxicity at 49.5 μM in iSLK-puro (KSHV-negative) cells and at 72.5 μM in iSLK-BAC16 (KSHV-positive) cells. Caspase 3/7 activities were slightly suppressed by genipin treatment in iSLK-BAC16 cells while significantly induced in iSLK-puro cells. Production of the KSHV latency-associated nuclear antigen (LANA), but not that of the R-transactivator (RTA) protein, was significantly induced by genipin treatment at lower concentration. Consistent with the LANA upregulation, KSHV LANA transcripts, but not RTA transcripts, were expressed at a higher level. Furthermore, KSHV intracellular copy numbers were slightly increased at lower concentration of genipin, while KSHV extracellular copy numbers were significantly increased at higher concentration of genipin. Interestingly, genipin treatment at a lower concentration did induce the expression of DNA (cytosine-5)-methyltransferase 1 (DNMT1); however, a co-immunoprecipitation assay showed that the DNMT1 and LANA induced by genipin did not co

  1. Gender Difference of Kaposi’s sarcoma-associated Herpesvirus Infection in Population with Schistosomiasis in Rural China

    PubMed Central

    Fu, Bishi; Xia, Fan; Li, Baolin; Ouyang, Xinxing; Gao, Shou-Jiang; Yang, Rongge; Wang, Linding

    2012-01-01

    Summary Kaposi sarcoma-associated herpesvirus (KSHV) is the causal agent of (KS), a common cancer in AIDS patients. The risk factors for KSHV infection have been extensively studied in Western countries but remain largely undefined in other parts of the World. Schistosomiasis caused by infection of Schistosoma japonicum is recently identified as a cofactor for KSHV infection in rural Egypt. In this study, we examined the seroprevalence of KSHV in a population with high incidence of Schistomasis along the Yangtze River in China. The seroprevalence of KSHV is slightly higher in subjects with than without Schistosomiasis but it is not statistically significant (8.4% vs 6.6%, p = 0.204). The seroprevalence of KSHV is significantly higher in female than male subjects (9.3% vs 5.9%, OR: 1.621, 95% CI: 1.084–2.425, p = 0.019). When adjusted for gender, the seroprevalence of KSHV is significantly higher in subjects with than without Schistosomiasis in male subjects (8.4% vs 2.8%, OR: 3.170, 95% CI: 1.501–6.694, p = 0.002). PMID:22814163

  2. The Chromatin Landscape of Kaposi’s Sarcoma-Associated Herpesvirus

    PubMed Central

    Toth, Zsolt; Brulois, Kevin; Jung, Jae U.

    2013-01-01

    Kaposi’s sarcoma-associated herpesvirus is an oncogenic γ-herpesvirus that causes latent infection in humans. In cells, the viral genome adopts a highly organized chromatin structure, which is controlled by a wide variety of cellular and viral chromatin regulatory factors. In the past few years, interrogation of the chromatinized KSHV genome by whole genome-analyzing tools revealed that the complex chromatin landscape spanning the viral genome in infected cells has important regulatory roles during the viral life cycle. This review summarizes the most recent findings regarding the role of histone modifications, histone modifying enzymes, DNA methylation, microRNAs, non-coding RNAs and the nuclear organization of the KSHV epigenome in the regulation of latent and lytic viral gene expression programs as well as their connection to KSHV-associated pathogenesis. PMID:23698402

  3. The Ubiquitin System and Kaposi’s Sarcoma-Associated Herpesvirus

    PubMed Central

    Ashizawa, Akira; Higashi, Chizuka; Masuda, Kazuki; Ohga, Rie; Taira, Takahiro; Fujimuro, Masahiro

    2012-01-01

    Ubiquitination is a post-translational modification in which one or more ubiquitin molecules are covalently linked to lysine residues of target proteins. The ubiquitin system plays a key role in the regulation of protein degradation, which contributes to cell signaling, vesicular trafficking, apoptosis, and immune regulation. Bacterial and viral pathogens exploit the cellular ubiquitin system by encoding their own proteins to serve their survival and replication in infected cells. Recent studies have revealed that Kaposi’s sarcoma-associated herpesvirus (KSHV) manipulates the ubiquitin system of infected cells to facilitate cell proliferation, anti-apoptosis, and evasion from immunity. This review summarizes recent developments in our understanding of the molecular mechanisms used by KSHV to interact with the cellular ubiquitin machinery. PMID:22375140

  4. Kaposi sarcoma–associated herpesvirus: immunobiology, oncogenesis, and therapy

    PubMed Central

    Dittmer, Dirk P.

    2016-01-01

    Kaposi sarcoma–associated herpesvirus (KSHV), also known as human herpesvirus 8, is the etiologic agent underlying Kaposi sarcoma, primary effusion lymphoma, and multicentric Castleman’s disease. This human gammaherpesvirus was discovered in 1994 by Drs. Yuan Chang and Patrick Moore. Today, there are over five thousand publications on KSHV and its associated malignancies. In this article, we review recent and ongoing developments in the KSHV field, including molecular mechanisms of KSHV pathogenesis, clinical aspects of KSHV-associated diseases, and current treatments for cancers associated with this virus. PMID:27584730

  5. Combination chemotherapy and alpha-interferon in the treatment of Kaposi's sarcoma associated with acquired immune deficiency syndrome.

    PubMed

    Shepherd, F A; Evans, W K; Garvey, B; Read, S E; Klein, M; Fanning, M M; Coates, R

    1988-10-01

    Thirteen men with a median age of 37 (range 28 to 46) years who had extensive Kaposi's sarcoma associated with acquired immune deficiency syndrome (AIDS) were treated with combination chemotherapy and alpha-interferon. Four patients had stage III disease and nine had stage IV disease (one with pulmonary and eight with gastrointestinal involvement). Treatment consisted of monthly courses of actinomycin D, 1 mg/m2, and vinblastine sulfate, 6 mg/m2, given intravenously on day 1, bleomycin, 10 mg/m2 given intravenously on days 1 and 8, and human lymphoblastoid (alpha-) interferon, 10 million U/m2 given subcutaneously three times a week for six doses starting on day 14. Forty-one treatment cycles (median 3, range 1 to 12) were administered. The median granulocyte and platelet counts on day 14 before the start of interferon therapy were 600 X 10(9)/L and 134 X 10(9)/L respectively; the counts did not fall further during interferon therapy. There was no difference in T-cell subsets, 2',5'-oligoadenylate synthetase level or results of blastogenesis studies after interferon therapy. Four patients required admission to hospital for neutropenia-associated fever. A complete response (of 24 weeks' duration) was seen in one patient and a partial response (of 14 to 44 weeks' duration) in four. One patient had a mixed response, with regression of skin involvement but progression of pulmonary disease. The median length of survival was 48 (range 4 to 143) weeks. Eleven patients died of progressive Kaposi's sarcoma, one of lymphoma and one of Pneumocystis carinii pneumonia. The results suggest that this form of therapy is not appropriate for patients with Kaposi's sarcoma associated with AIDS.

  6. Kinetics of Kaposi’s Sarcoma-Associated Herpesvirus Gene Expression

    PubMed Central

    Sun, Ren; Lin, Su-Fang; Staskus, Katherine; Gradoville, Lyndle; Grogan, Elizabeth; Haase, Ashley; Miller, George

    1999-01-01

    Herpesvirus gene expression can be classified into four distinct kinetic stages: latent, immediate early, early, and late. Here we characterize the kinetic class of a group of 16 Kaposi’s sarcoma-associated herpesvirus (KSHV)/human herpesvirus 8 genes in a cultured primary effusion cell line and examine the expression of a subset of these genes in KS biopsies. Expression of two latent genes, LANA and vFLIP, was constitutive and was not induced by chemicals that induce the lytic cycle in primary effusion lymphoma (PEL) cell lines. An immediate-early gene, Rta (open reading frame 50 [ORF50]), was induced within 4 h of the addition of n-butyrate, and its 3.6-kb mRNA was resistant to inhibition by cycloheximide. Early genes, including K3 and K5 that are homologues of the “immediate-early” gene of bovine herpesvirus 4, K8 that is a positional homologue of Epstein-Barr virus BZLF1, vMIP II, vIL-6, and polyadenylated nuclear (PAN) RNA, appeared 8 to 13 h after chemical induction. A second group of early genes that were slightly delayed in their appearance included viral DHFR, thymidylate synthase, vMIP I, G protein-coupled receptor, K12, vBcl2, and a lytic transcript that overlapped LANA. The transcript of sVCA (ORF65), a late gene whose expression was abolished by Phosphonoacetic acid, an inhibitor of KSHV DNA replication, did not appear until 30 h after induction. Single-cell assays indicated that the induction of lytic cycle transcripts resulted from the recruitment of additional cells into the lytic cycle. In situ hybridization of KS biopsies showed that about 3% of spindle-shaped tumor cells expressed Rta, ORF K8, vIL-6, vMIP I, vBcl-2, PAN RNA, and sVCA. Our study shows that several KSHV-encoded homologues of cellular cytokines, chemokines, and antiapoptotic factors are expressed during the viral lytic cycle in PEL cell lines and in KS biopsies. The lytic cycle of KSHV, probably under the initial control of the KSHV/Rta gene, may directly contribute to tumor

  7. Kaposi’s Sarcoma-Associated Herpesvirus Viral Interferon Regulatory Factor

    PubMed Central

    Li, Mengtao; Lee, Heuiran; Guo, Jie; Neipel, Frank; Fleckenstein, Bernhard; Ozato, Keiko; Jung, Jae U.

    1998-01-01

    Interferons (IFNs) are a family of multifunctional cytokines with antiviral activities. The K9 open reading frame of Kaposi’s sarcoma-associated herpesvirus (KSHV) exhibits significant homology with cellular IFN regulatory factors (IRFs). We have investigated the functional consequence of K9 expression in IFN-mediated signal transduction. Expression of K9 dramatically repressed transcriptional activation induced by IFN-α, -β, and -γ. Further, it induced transformation of NIH 3T3 cells, resulting in morphologic changes, focus formation, and growth in reduced-serum conditions. The expression of antisense K9 in KSHV-infected BCBL-1 cells consistently increased IFN-mediated transcriptional activation but drastically decreased the expression of certain KSHV genes. Thus, the K9 gene of KSHV encodes the first virus-encoded IRF (v-IRF) which functions as a repressor for cellular IFN-mediated signal transduction. In addition, v-IRF likely plays an important role in regulating KSHV gene expression. These results suggest that KSHV employs an unique mechanism to antagonize IFN-mediated antiviral activity by harboring a functional v-IRF. PMID:9620998

  8. Kaposi sarcoma herpesvirus-associated cancers and related diseases.

    PubMed

    Goncalves, Priscila H; Ziegelbauer, Joseph; Uldrick, Thomas S; Yarchoan, Robert

    2017-01-01

    This review discusses the pathogenesis and recent advances in the management of Kaposi sarcoma herpesvirus (KSHV)-associated diseases. KSHV, a gammaherpesvirus, causes several tumors and related diseases, including Kaposi sarcoma, a form of multicentric Castleman disease (KSHV-MCD), and primary effusion lymphoma. These most often develop in patients infected with human immunodeficiency virus (HIV). KSHV inflammatory cytokine syndrome (KICS) is a newly described syndrome with high mortality that has inflammatory symptoms-like MCD but not the pathologic lymph node findings. KSHV-associated diseases are often associated with dysregulated human interleukin-6, and KSHV encodes a viral interleukin-6, both of which contribute to disease pathogenesis. Treatment of HIV is important in HIV-infected patients. Strategies to prevent KSHV infection may reduce the incidence of these tumors. Pomalidomide, an immunomodulatory agent, has activity in Kaposi sarcoma. Rituximab is active in KSHV-MCD but can cause Kaposi sarcoma exacerbation; rituximab plus liposomal doxorubicin is useful to treat KSHV-MCD patients with concurrent Kaposi sarcoma. KSHV is the etiological agents of all forms of Kaposi sarcoma and several other diseases. Strategies employing immunomodulatory agents, cytokine inhibition, and targeting of KSHV-infected cells are areas of active research.

  9. NEDDylation Is Essential for Kaposi’s Sarcoma-Associated Herpesvirus Latency and Lytic Reactivation and Represents a Novel Anti-KSHV Target

    PubMed Central

    Hughes, David J.; Wood, Jennifer J.; Jackson, Brian R.; Baquero-Pérez, Belinda; Whitehouse, Adrian

    2015-01-01

    Kaposi’s sarcoma-associated herpesvirus (KSHV) is the causative agent of Kaposi's sarcoma (KS) and primary effusion lymphoma (PEL), which are aggressive malignancies associated with immunocompromised patients. For many non-viral malignancies, therapeutically targeting the ubiquitin proteasome system (UPS) has been successful. Likewise, laboratory studies have demonstrated that inhibition of the UPS might provide a promising avenue for the treatment of KSHV-associated diseases. The largest class of E3 ubiquitin ligases are the cullin-RING ligases (CRLs) that are activated by an additional ubiquitin-like protein, NEDD8. We show that pharmacological inhibition of NEDDylation (using the small molecule inhibitor MLN4924) is cytotoxic to PEL cells by inhibiting NF-κB. We also show that CRL4B is a novel regulator of latency as its inhibition reactivated lytic gene expression. Furthermore, we uncovered a requirement for NEDDylation during the reactivation of the KSHV lytic cycle. Intriguingly, inhibition prevented viral DNA replication but not lytic cycle-associated gene expression, highlighting a novel mechanism that uncouples these two features of KSHV biology. Mechanistically, we show that MLN4924 treatment precluded the recruitment of the viral pre-replication complex to the origin of lytic DNA replication (OriLyt). These new findings have revealed novel mechanisms that regulate KSHV latency and reactivation. Moreover, they demonstrate that inhibition of NEDDylation represents a novel approach for the treatment of KSHV-associated malignancies. PMID:25794275

  10. A role for MALT1 activity in Kaposi's sarcoma-associated herpes virus latency and growth of primary effusion lymphoma.

    PubMed

    Bonsignore, L; Passelli, K; Pelzer, C; Perroud, M; Konrad, A; Thurau, M; Stürzl, M; Dai, L; Trillo-Tinoco, J; Del Valle, L; Qin, Z; Thome, M

    2017-03-01

    Primary effusion lymphoma (PEL) is an incurable malignancy that develops in immunodeficient patients as a consequence of latent infection of B-cells with Kaposi's sarcoma-associated herpes virus (KSHV). Malignant growth of KSHV-infected B cells requires the activity of the transcription factor nuclear factor (NF)-κB, which controls maintenance of viral latency and suppression of the viral lytic program. Here we show that the KSHV proteins K13 and K15 promote NF-κB activation via the protease mucosa-associated lymphoid tissue lymphoma translocation protein-1 (MALT1), a key driver of NF-κB activation in lymphocytes. Inhibition of the MALT1 protease activity induced a switch from the latent to the lytic stage of viral infection, and led to reduced growth and survival of PEL cell lines in vitro and in a xenograft model. These results demonstrate a key role for the proteolytic activity of MALT1 in PEL, and provide a rationale for the pharmacological targeting of MALT1 in PEL therapy.

  11. A role for MALT1 activity in Kaposi's sarcoma-associated herpes virus latency and growth of primary effusion lymphoma

    PubMed Central

    Bonsignore, L; Passelli, K; Pelzer, C; Perroud, M; Konrad, A; Thurau, M; Stürzl, M; Dai, L; Trillo-Tinoco, J; Del Valle, L; Qin, Z; Thome, M

    2017-01-01

    Primary effusion lymphoma (PEL) is an incurable malignancy that develops in immunodeficient patients as a consequence of latent infection of B-cells with Kaposi's sarcoma-associated herpes virus (KSHV). Malignant growth of KSHV-infected B cells requires the activity of the transcription factor nuclear factor (NF)-κB, which controls maintenance of viral latency and suppression of the viral lytic program. Here we show that the KSHV proteins K13 and K15 promote NF-κB activation via the protease mucosa-associated lymphoid tissue lymphoma translocation protein-1 (MALT1), a key driver of NF-κB activation in lymphocytes. Inhibition of the MALT1 protease activity induced a switch from the latent to the lytic stage of viral infection, and led to reduced growth and survival of PEL cell lines in vitro and in a xenograft model. These results demonstrate a key role for the proteolytic activity of MALT1 in PEL, and provide a rationale for the pharmacological targeting of MALT1 in PEL therapy. PMID:27538487

  12. Cellular and Kaposi's sarcoma-associated herpes virus microRNAs in sepsis and surgical trauma

    PubMed Central

    Tudor, S; Giza, D E; Lin, H Y; Fabris, L; Yoshiaki, K; D'Abundo, L; Toale, K M; Shimizu, M; Ferracin, M; Challagundla, K B; Angelica Cortez, M; Fuentes-Mattei, E; Tulbure, D; Gonzalez, C; Henderson, J; Row, M; Rice, T W; Ivan, C; Negrini, M; Fabbri, M; Morris, J S; Yeung, S-C J; Vasilescu, C; Calin, G A

    2014-01-01

    Once a patient is in septic shock, survival rates drop by 7.6% for every hour of delay in antibiotic therapy. Biomarkers based on the molecular mechanism of sepsis are important for timely diagnosis and triage. Here, we study the potential roles of a panel of cellular and viral miRNAs as sepsis biomarkers. We performed genome-wide microRNA (miRNA) expression profiling in leukocytes from septic patients and nonseptic controls, combined with quantitative RT-PCR in plasmas from two cohorts of septic patients, two cohorts of nonseptic surgical patients and healthy volunteers. Enzyme-linked immunosorbent assay, miRNA transfection and chromatin immunoprecipitation were used to study the effects of Kaposi sarcoma herpes virus (KSHV) miRNAs on interleukin's secretion. Differences related to sepsis etiology were noted for plasma levels of 10 cellular and 2 KSHV miRNAs (miR-K-10b and miR-K-12-12*) between septic and nonseptic patients. All the sepsis groups had high KSHV miRNAs levels compared with controls; Afro-American patients had higher levels of KSHV-miR-K12-12* than non-Afro-American patients. Both KSHV miRNAs were increased on postoperative day 1, but returned to baseline on day 7; they acted as direct agonists of Toll-like receptor 8 (TLR8), which might explain the increased secretion of the IL-6 and IL-10. Cellular and KSHV miRNAs are differentially expressed in sepsis and early postsurgical patients and may be exploited for diagnostic and therapeutic purposes. Increased miR-K-10b and miR-K12-12* are functionally involved in sepsis as agonists of TLR8, forming a positive feedback that may lead to cytokine dysregulation. PMID:25476907

  13. Cellular and Kaposi's sarcoma-associated herpes virus microRNAs in sepsis and surgical trauma.

    PubMed

    Tudor, S; Giza, D E; Lin, H Y; Fabris, L; Yoshiaki, K; D'Abundo, L; Toale, K M; Shimizu, M; Ferracin, M; Challagundla, K B; Cortez, M Angelica; Fuentes-Mattei, E; Tulbure, D; Gonzalez, C; Henderson, J; Row, M; Rice, T W; Ivan, C; Negrini, M; Fabbri, M; Morris, J S; Yeung, S-C J; Vasilescu, C; Calin, G A

    2014-12-04

    Once a patient is in septic shock, survival rates drop by 7.6% for every hour of delay in antibiotic therapy. Biomarkers based on the molecular mechanism of sepsis are important for timely diagnosis and triage. Here, we study the potential roles of a panel of cellular and viral miRNAs as sepsis biomarkers. We performed genome-wide microRNA (miRNA) expression profiling in leukocytes from septic patients and nonseptic controls, combined with quantitative RT-PCR in plasmas from two cohorts of septic patients, two cohorts of nonseptic surgical patients and healthy volunteers. Enzyme-linked immunosorbent assay, miRNA transfection and chromatin immunoprecipitation were used to study the effects of Kaposi sarcoma herpes virus (KSHV) miRNAs on interleukin's secretion. Differences related to sepsis etiology were noted for plasma levels of 10 cellular and 2 KSHV miRNAs (miR-K-10b and miR-K-12-12*) between septic and nonseptic patients. All the sepsis groups had high KSHV miRNAs levels compared with controls; Afro-American patients had higher levels of KSHV-miR-K12-12* than non-Afro-American patients. Both KSHV miRNAs were increased on postoperative day 1, but returned to baseline on day 7; they acted as direct agonists of Toll-like receptor 8 (TLR8), which might explain the increased secretion of the IL-6 and IL-10. Cellular and KSHV miRNAs are differentially expressed in sepsis and early postsurgical patients and may be exploited for diagnostic and therapeutic purposes. Increased miR-K-10b and miR-K12-12* are functionally involved in sepsis as agonists of TLR8, forming a positive feedback that may lead to cytokine dysregulation.

  14. Molecular and immunohistochemical detection of Kaposi sarcoma herpesvirus/human herpesvirus-8.

    PubMed

    Chadburn, Amy; Wilson, Janet; Wang, Y Lynn

    2013-01-01

    Kaposi sarcoma herpesvirus/human herpesvirus-8 (KSHV/HHV-8) is etiologically related to the development of several human diseases, including Kaposi sarcoma, primary effusion lymphoma (PEL)/extra-cavitary (EC) PEL, multicentric Castleman disease (MCD), and large B-cell lymphoma arising in KSHV/HHV-8-associated multicentric Castleman disease. Although serologic studies can identify persons infected with this virus, molecular genetics, specifically PCR (polymerase chain reaction) and immunohistochemical techniques, are rapid, sensitive, and specific, and are able to more closely link KSHV/HHV-8 to a given disease process. As these KSHV/HHV-8-related diseases cause significant morbidity and mortality in affected individuals, the identification of the virus within lesional tissue will allow for more targeted therapy.

  15. Quantitative Determinations of Anti-Kaposi’s Sarcoma-Associated Herpesvirus (KSHV) Antibody Levels in Men Who Have Sex with Men

    PubMed Central

    Gogineni, Emile; Marshall, Vickie; Miley, Wendell; Bayat, Ahmad; Whitby, Denise; Kovacs, Joseph A.; Burbelo, Peter D.

    2013-01-01

    Infection with Kaposi’s Sarcoma-Associated Herpesvirus (KSHV/HHV-8) is common among men who have sex with men (MSM). Here quantitative anti-KSHV antibody levels were measured using Luciferase Immunoprecipitation Systems (LIPS) in a MSM cohort with and without HIV from the NIH Clinical Center. Antibodies were detected using a mixture of four KSHV antigens in the MSM cohort and in Kaposi Sarcoma (KS) patients. Along with HIV status, these results were compared with K8.1 and ORF73 ELISA, PCR virus detection, and additional LIPS testing. LIPS revealed that 25% (76/307) of the MSM cohort were KSHV seropositive, including 59 HIV+ and 17 HIV− subjects. The anti-KSHV antibody levels detected by LIPS were not statistically different between the KSHV+/HIV+ and KSHV+/HIV− subgroups, but were lower than the KS patients (P<0.0001). ELISA analysis of the MSM cohort detected a 35.5% frequency of KSHV infection and showed agreement with 81% of the samples evaluated by LIPS. Further LIPS testing with v-cyclin, a second ORF73 fragment and ORF38 reconciled some of the differences observed between LIPS and the ELISA immunoassays and the revised LIPS seroprevalence in the MSM cohort was increased to 31%. Additional quantitative antibody analysis demonstrated statistically lower KSHV antibody levels in MSM compared to KS patients, but no difference was found between KSHV infected with and without HIV coinfection. These findings also suggest that antibodies against v-cyclin and ORF38 are useful for identifying patients with asymptomatic KSHV infection. PMID:23541691

  16. Kaposi's Sarcoma Herpesvirus MicroRNAs Induce Metabolic Transformation of Infected Cells

    PubMed Central

    Yogev, Ohad; Lagos, Dimitris; Enver, Tariq; Boshoff, Chris

    2014-01-01

    Altered cell metabolism is inherently connected with pathological conditions including cancer and viral infections. Kaposi's sarcoma-associated herpesvirus (KSHV) is the etiological agent of Kaposi's sarcoma (KS). KS tumour cells display features of lymphatic endothelial differentiation and in their vast majority are latently infected with KSHV, while a small number are lytically infected, producing virions. Latently infected cells express only a subset of viral genes, mainly located within the latency-associated region, among them 12 microRNAs. Notably, the metabolic properties of KSHV-infected cells closely resemble the metabolic hallmarks of cancer cells. However, how and why KSHV alters host cell metabolism remains poorly understood. Here, we investigated the effect of KSHV infection on the metabolic profile of primary dermal microvascular lymphatic endothelial cells (LEC) and the functional relevance of this effect. We found that the KSHV microRNAs within the oncogenic cluster collaborate to decrease mitochondria biogenesis and to induce aerobic glycolysis in infected cells. KSHV microRNAs expression decreases oxygen consumption, increase lactate secretion and glucose uptake, stabilize HIF1α and decreases mitochondria copy number. Importantly this metabolic shift is important for latency maintenance and provides a growth advantage. Mechanistically we show that KSHV alters host cell energy metabolism through microRNA-mediated down regulation of EGLN2 and HSPA9. Our data suggest that the KSHV microRNAs induce a metabolic transformation by concurrent regulation of two independent pathways; transcriptional reprograming via HIF1 activation and reduction of mitochondria biogenesis through down regulation of the mitochondrial import machinery. These findings implicate viral microRNAs in the regulation of the cellular metabolism and highlight new potential avenues to inhibit viral latency. PMID:25255370

  17. Antibodies against lytic and latent Kaposi's sarcoma-associated herpes virus antigens and lymphoma in the European EpiLymph case–control study

    PubMed Central

    Benavente, Y; Mbisa, G; Labo, N; Casabonne, D; Becker, N; Maynadie, M; Foretova, L; Cocco, P L; Nieters, A; Staines, A; Bofetta, P; Brennan, P; Whitby, D; de Sanjosé, S

    2011-01-01

    Background: Kaposi's sarcoma-associated herpes virus is associated with primary effusion lymphoma and multicentric Castleman's disease. Methods: Seropositivity to lytic and latent Kaposi's sarcoma herpes virus (KSHV) antigens were examined in 2083 lymphomas and 2013 controls from six European countries. Results: Antibodies against KSHV latent and lytic antigens were detectable in 4.5% and 3.4% of controls, respectively, and 3.6% of cases (P>0.05). The KSHV seropositivity was associated with splenic marginal zone lymphoma (SMZL) (odds ratio (OR)=4.11, 95% confidence interval (CI)=1.57–10.83) and multiple myeloma (OR=0.31, 95% CI=0.11–0.85). Conclusion: The KSHV is unlikely to contribute importantly to lymphomagenesis among immunocompetent subjects. However, the observed association with SMZL may underline a chronic antigen mechanism in its aetiology. PMID:21952625

  18. Next-Generation Sequencing in the Understanding of Kaposi’s Sarcoma-Associated Herpesvirus (KSHV) Biology

    PubMed Central

    Strahan, Roxanne; Uppal, Timsy; Verma, Subhash C.

    2016-01-01

    Non-Sanger-based novel nucleic acid sequencing techniques, referred to as Next-Generation Sequencing (NGS), provide a rapid, reliable, high-throughput, and massively parallel sequencing methodology that has improved our understanding of human cancers and cancer-related viruses. NGS has become a quintessential research tool for more effective characterization of complex viral and host genomes through its ever-expanding repertoire, which consists of whole-genome sequencing, whole-transcriptome sequencing, and whole-epigenome sequencing. These new NGS platforms provide a comprehensive and systematic genome-wide analysis of genomic sequences and a full transcriptional profile at a single nucleotide resolution. When combined, these techniques help unlock the function of novel genes and the related pathways that contribute to the overall viral pathogenesis. Ongoing research in the field of virology endeavors to identify the role of various underlying mechanisms that control the regulation of the herpesvirus biphasic lifecycle in order to discover potential therapeutic targets and treatment strategies. In this review, we have complied the most recent findings about the application of NGS in Kaposi’s sarcoma-associated herpesvirus (KSHV) biology, including identification of novel genomic features and whole-genome KSHV diversities, global gene regulatory network profiling for intricate transcriptome analyses, and surveying of epigenetic marks (DNA methylation, modified histones, and chromatin remodelers) during de novo, latent, and productive KSHV infections. PMID:27043613

  19. Multiplexed Colorimetric Detection of Kaposi’s Sarcoma Associated Herpesvirus and Bartonella DNA using Gold and Silver Nanoparticles

    PubMed Central

    Mancuso, Matthew; Jiang, Li; Cesarman, Ethel; Erickson, David

    2013-01-01

    Kaposi’s sarcoma (KS) is an infectious cancer occurring most commonly in human immunodeficiency virus (HIV) positive patients and in endemic regions, such as Sub-Saharan Africa, where KS is among the top four most prevalent cancers. The cause of KS is the Kaposi’s sarcoma-associated herpesvirus (KSHV, also called HHV-8), an oncogenic herpesvirus that while routinely diagnosed in developed nations, provides challenges to developing world medical providers and point-of-care detection. A major challenge in the diagnosis of KS is the existence of a number of other diseases with similar clinical presentation and histopathological features, requiring the detection of KSHV in a biopsy sample. In this work we develop an answer to this challenge by creating a multiplexed one-pot detection system for KSHV DNA and DNA from a frequently confounding disease, bacillary angiomatosis. Gold and silver nanoparticle aggregation reactions are tuned for each target and a multi-color change system is developed capable of detecting both targets down to levels between 1 nM and 2 nM. The system developed here could later be integrated with microfluidic sample processing to create a final device capable of solving the two major challenges in point-of-care KS detection. PMID:23340972

  20. Nuclear Localization and Cleavage of STAT6 Is Induced by Kaposi’s Sarcoma-Associated Herpesvirus for Viral Latency

    PubMed Central

    Zhang, Liming; Li, Yuhong; Feng, Yanling; Xu, Jianqing; Wang, Bin; Yuan, Zhenghong; Robertson, Erle S.; Cai, Qiliang

    2017-01-01

    Emerging evidence implies that STAT6 plays an important role in both the adaptive and innate immune responses to virus infection. Kaposi’s sarcoma-associated herpesvirus (KSHV) is an oncogenic γ-herpesvirus agent associated with several human malignancies, including Kaposi’s sarcoma (KS) and primary effusion lymphomas (PELs). Previously, we demonstrated that KSHV blocks IL-4-induced STAT6 phosphorylation and retains a basal IL-13/STAT6 constitutive activation for cell survival and proliferation. However, the mechanism by which KSHV regulates STAT6 remains largely unknown. Here, we found that KSHV-encoded LANA interacts with STAT6 and promotes nuclear localization of STAT6 independent of the tyrosine 641-phosphorylation state. Moreover, nuclear localization of STAT6 is also dramatically increased in KS tissue. The latent antigen LANA induces serine protease-mediated cleavage of STAT6 in the nucleus, where the cleaved STAT6 lacking transactivation domain functions as a dominant-negative regulator to repress transcription of Replication and Transcription Activator (RTA) and in turn shut off viral lytic replication. Blockade of STAT6 by small interference RNA dramatically enhances expression of RTA, and in turn reduces KSHV-infected endothelial cell growth and colony formation. Taken together, these results suggest that nuclear localization and cleavage of STAT6 is important for modulating the viral latency and pathogenesis of KSHV. PMID:28099521

  1. Hsp70 Isoforms Are Essential for the Formation of Kaposi’s Sarcoma-Associated Herpesvirus Replication and Transcription Compartments

    PubMed Central

    Baquero-Pérez, Belinda; Whitehouse, Adrian

    2015-01-01

    Kaposi’s sarcoma-associated herpesvirus (KSHV) is an oncogenic herpesvirus associated with various AIDS-related malignancies. Like other herpesviruses, multiple processes required for KSHV lytic replication, including viral transcription, viral DNA synthesis and capsid assembly occur in virus-induced intranuclear structures, termed replication and transcription compartments (RTCs). Here we utilised a novel methodology, combining subcellular fractionation and quantitative proteomics, to identify cellular proteins which are recruited to KSHV-induced RTCs and thus play a key role in KSHV lytic replication. We show that several isoforms of the HSP70 chaperone family, Hsc70 and iHsp70, are redistributed from the cytoplasm into the nucleus coinciding with the initial formation of KSHV-induced RTCs. We demonstrate that nuclear chaperone foci are dynamic, initially forming adjacent to newly formed KSHV RTCs, however during later time points the chaperones move within KSHV RTCs and completely co-localise with actively replicating viral DNA. The functional significance of Hsp70 isoforms recruitment into KSHV RTCs was also examined using the specific Hsp70 isoform small molecule inhibitor, VER-155008. Intriguingly, results highlight an essential role of Hsp70 isoforms in the KSHV replication cycle independent of protein stability and maturation. Notably, inhibition of Hsp70 isoforms precluded KSHV RTC formation and RNA polymerase II (RNAPII) relocalisation to the viral genome leading to the abolishment of global KSHV transcription and subsequent viral protein synthesis and DNA replication. These new findings have revealed novel mechanisms that regulate KSHV lytic replication and highlight the potential of HSP70 inhibitors as novel antiviral agents. PMID:26587836

  2. Structural Analysis of Thymidylate Synthase from Kaposi’s Sarcoma-Associated Herpesvirus with the Anticancer Drug Raltitrexed

    PubMed Central

    Choi, Yong Mi; Yeo, Hyun Ku; Park, Young Woo; Lee, Jae Young

    2016-01-01

    Kaposi’s sarcoma-associated herpesvirus (KSHV) is a highly infectious human herpesvirus that causes Kaposi’s sarcoma. KSHV encodes functional thymidylate synthase, which is a target for anticancer drugs such as raltitrexed or 5-fluorouracil. Thymidylate synthase catalyzes the conversion of 2′-deoxyuridine-5′-monophosphate (dUMP) to thymidine-5′-monophosphate (dTMP) using 5,10-methylenetetrahydrofolate (mTHF) as a co-substrate. The crystal structures of thymidylate synthase from KSHV (apo), complexes with dUMP (binary), and complexes with both dUMP and raltitrexed (ternary) were determined at 1.7 Å, 2.0 Å, and 2.4 Å, respectively. While the ternary complex structures of human thymidylate synthase and E. coli thymidylate synthase had a closed conformation, the ternary complex structure of KSHV thymidylate synthase was observed in an open conformation, similar to that of rat thymidylate synthase. The complex structures of KSHV thymidylate synthase did not have a covalent bond between the sulfhydryl group of Cys219 and C6 atom of dUMP, unlike the human thymidylate synthase. The catalytic Cys residue demonstrated a dual conformation in the apo structure, and its sulfhydryl group was oriented toward the C6 atom of dUMP with no covalent bond upon ligand binding in the complex structures. These structural data provide the potential use of antifolates such as raltitrexed as a viral induced anticancer drug and structural basis to design drugs for targeting the thymidylate synthase of KSHV. PMID:27936107

  3. Identification and Characterization of Kaposi’s Sarcoma-Associated Herpesvirus K8.1 Virion Glycoprotein

    PubMed Central

    Li, Mengtao; MacKey, John; Czajak, Susan C.; Desrosiers, Ronald C.; Lackner, Andrew A.; Jung, Jae U.

    1999-01-01

    Kaposi’s sarcoma-associated herpesvirus (KSHV) has been consistently identified in Kaposi’s sarcomas (KS), body cavity-based lymphomas (BCBL), and some forms of Castleman’s disease. Previous serological tests with KS patient sera have detected lytic-cycle polypeptides from KSHV-infected BCBL cells. We have found that these polypeptides are predominantly encoded by the K8.1 open reading frame, which is present in the same genomic position as virion envelope glycoproteins of other gammaherpesviruses. The cDNA of K8.1 from BCBL-1 cells was found to encode a glycosylated protein with an apparent molecular mass of 37 kDa. K8.1 was found to be expressed during lytic KSHV replication in BCBL-1 cells and was localized on the surface of cells and virions. The results of immunofluorescence and immunoelectron microscopy suggest that KSHV acquires K8.1 protein on its virion surface during the process of budding at the plasma cell membrane. When KSHV K8.1 derived from mammalian cells was used as an antigen in immunoblot tests, antibodies to K8.1 were detected in 18 of 20 KS patients and in 0 of 10 KS-negative control subjects. These results demonstrate that the K8.1 gene encodes a KSHV virion-associated glycoprotein and suggest that antibodies to K8.1 may prove useful as contributory serological markers for infection by KSHV. PMID:9882339

  4. Regulation of the Abundance of Kaposi’s Sarcoma-Associated Herpesvirus ORF50 Protein by Oncoprotein MDM2

    PubMed Central

    Chang, Tzu-Hsuan; Chen, Lee-Wen; Shih, Ying-Ju; Chang, Li-Kwan; Liu, Shih-Tung; Chang, Pey-Jium

    2016-01-01

    The switch between latency and the lytic cycle of Kaposi’s sarcoma-associated herpesvirus (KSHV) is controlled by the expression of virally encoded ORF50 protein. Thus far, the regulatory mechanism underlying the protein stability of ORF50 is unknown. Our earlier studies have demonstrated that a protein abundance regulatory signal (PARS) at the ORF50 C-terminal region modulates its protein abundance. The PARS region consists of PARS-I (aa 490–535) and PARS-II (aa 590–650), and mutations in either component result in abundant expression of ORF50. Here, we show that ORF50 protein is polyubiquitinated and its abundance is controlled through the proteasomal degradation pathway. The PARS-I motif mainly functions as a nuclear localization signal in the control of ORF50 abundance, whereas the PARS-II motif is required for the binding of ubiquitin enzymes in the nucleus. We find that human oncoprotein MDM2, an ubiquitin E3 ligase, is capable of interacting with ORF50 and promoting ORF50 degradation in cells. The interaction domains between both proteins are mapped to the PARS region of ORF50 and the N-terminal 220-aa region of MDM2. Additionally, we identify lysine residues at positions 152 and 154 in the N-terminal domain of ORF50 critically involved in MDM2-mediated downregulation of ORF50 levels. Within KSHV-infected cells, the levels of MDM2 were greatly reduced during viral lytic cycle and genetic knockdown of MDM2 in these cells favored the enhancement of ORF50 expression, supporting that MDM2 is a negative regulator of ORF50 expression. Collectively, the study elucidates the regulatory mechanism of ORF50 stability and implicates that MDM2 may have a significant role in the maintenance of viral latency by lowering basal level of ORF50. PMID:27698494

  5. Kaposi's sarcoma herpesvirus C-terminal LANA concentrates at pericentromeric and peri-telomeric regions of a subset of mitotic chromosomes

    SciTech Connect

    Kelley-Clarke, Brenna; Ballestas, Mary E.; Komatsu, Takashi; Kaye, Kenneth M. . E-mail: kkaye@rics.bwh.harvard.edu

    2007-01-20

    The Kaposi's sarcoma-associated herpesvirus (KSHV) latency-associated nuclear antigen (LANA) tethers KSHV terminal repeat (TR) DNA to mitotic chromosomes to efficiently segregate episomes to progeny nuclei. LANA contains N- and C-terminal chromosome binding regions. We now show that C-terminal LANA preferentially concentrates to paired dots at pericentromeric and peri-telomeric regions of a subset of mitotic chromosomes through residues 996-1139. Deletions within C-terminal LANA abolished both self-association and chromosome binding, consistent with a requirement for self-association to bind chromosomes. A deletion abolishing TR DNA binding did not affect chromosome targeting, indicating LANA's localization is not due to binding its recognition sequence in chromosomal DNA. LANA distributed similarly on human and non-human mitotic chromosomes. These results are consistent with C-terminal LANA interacting with a cell factor that concentrates at pericentromeric and peri-telomeric regions of mitotic chromosomes.

  6. Simian homologues of human herpesvirus 8.

    PubMed Central

    Damania, B; Desrosiers, R C

    2001-01-01

    Gamma-herpesviruses can be found in most primates including Old World an New World monkeys. The gamma-herpesvirinae are grouped into two classes: lymphocryptoviruses (gamma1) and rhadinoviruses (gamma2). The lymphocryptoviruses include Epstein-Barr virus, lymphocryptovirus of rhesus monkeys, and Herpesvirus papio of baboons. Rhadinoviruses that infect New World monkeys include Herpesvirus saimiri, whose natural host is the squirrel monkey, and Herpesvirus ateles, which infects spider monkeys. Rhadinoviruses that infect hominoids and Old World monkeys include Kaposi's sarcoma-associated herpesvirus, also known as HHV-8, and rhesus monkey rhadinovirus. PMID:11313010

  7. Simian homologues of human herpesvirus 8.

    PubMed

    Damania, B; Desrosiers, R C

    2001-04-29

    Gamma-herpesviruses can be found in most primates including Old World an New World monkeys. The gamma-herpesvirinae are grouped into two classes: lymphocryptoviruses (gamma1) and rhadinoviruses (gamma2). The lymphocryptoviruses include Epstein-Barr virus, lymphocryptovirus of rhesus monkeys, and Herpesvirus papio of baboons. Rhadinoviruses that infect New World monkeys include Herpesvirus saimiri, whose natural host is the squirrel monkey, and Herpesvirus ateles, which infects spider monkeys. Rhadinoviruses that infect hominoids and Old World monkeys include Kaposi's sarcoma-associated herpesvirus, also known as HHV-8, and rhesus monkey rhadinovirus.

  8. Kaposi's sarcoma herpesvirus-encoded latency-associated nuclear antigen stabilizes intracellular activated Notch by targeting the Sel10 protein.

    PubMed

    Lan, Ke; Verma, Subhash C; Murakami, Masanao; Bajaj, Bharat; Kaul, Rajeev; Robertson, Erle S

    2007-10-09

    Deregulation of the evolutionarily conserved Notch signaling is highly correlated with oncogenesis. Intracellular activated Notch (ICN) is a protooncogene linked to the transcription activation of a number of cellular genes involved in cell cycle regulation, differentiation, and proliferation. Stability of ICN is tightly regulated by the Sel10-mediated ubiquitin-proteasome pathway. Sel10 can function as a negative regulator of Notch and exhibits activities of a tumor-suppressor protein. This article shows that the Kaposi's sarcoma-associated herpesvirus (KSHV) latency-associated nuclear antigen (LANA) directly interacts with Sel10 and forms a complex in KSHV-infected cells. This results in suppression of ICN ubiquitination and degradation. The carboxyl terminus of LANA interacts with the F-box and WD40 domains of Sel10 and competes with ICN for binding to Sel10. This elevated level of ICN is also critical for maintaining the enhanced proliferation of KSHV-infected tumor cells. These findings describe a mechanism by which the KSHV-encoded LANA protein regulates ubiquitination of ICN mediated by the F-box component of the E3 ligase Sel10, leading to proliferation of the virus-infected cells.

  9. Human Herpesvirus 8 Genotype E in Patients with Kaposi Sarcoma, Peru

    PubMed Central

    Cassar, Olivier; Blondot, Marie-Lise; Mohanna, Salim; Jouvion, Gregory; Bravo, Francisco; Maco, Vicente; Duprez, Renan; Huerre, Michel; Gotuzzo, Eduardo

    2010-01-01

    To determine human herpesvirus 8 (HHV-8) K1 genotypes in patients with Kaposi sarcoma (KS) from Peru, we characterized HHV-8 in 25 KS biopsy samples. Our findings of 8 A, 1 B, 14 C, and 2 E subtypes showed high HHV-8 diversity in these patients and association between E genotype and KS development. PMID:20735933

  10. p120-catenin regulates VE-cadherin endocytosis and degradation induced by the Kaposi sarcoma-associated ubiquitin ligase K5.

    PubMed

    Nanes, Benjamin A; Grimsley-Myers, Cynthia M; Cadwell, Chantel M; Robinson, Brian S; Lowery, Anthony M; Vincent, Peter A; Mosunjac, Marina; Früh, Klaus; Kowalczyk, Andrew P

    2017-01-01

    Vascular endothelial (VE)-cadherin undergoes constitutive internalization driven by a unique endocytic motif that also serves as a p120-catenin (p120) binding site. p120 binding masks the motif, stabilizing the cadherin at cell junctions. This mechanism allows constitutive VE-cadherin endocytosis and recycling to contribute to adherens junction dynamics without resulting in junction disassembly. Here we identify an additional motif that drives VE-cadherin endocytosis and pathological junction disassembly associated with the endothelial-derived tumor Kaposi sarcoma. Human herpesvirus 8, which causes Kaposi sarcoma, expresses the MARCH family ubiquitin ligase K5. We report that K5 targets two membrane-proximal VE-cadherin lysine residues for ubiquitination, driving endocytosis and down-regulation of the cadherin. K5-induced VE-cadherin endocytosis does not require the constitutive endocytic motif. However, K5-induced VE-cadherin endocytosis is associated with displacement of p120 from the cadherin, and p120 protects VE-cadherin from K5. Thus multiple context-dependent signals drive VE-cadherin endocytosis, but p120 binding to the cadherin juxtamembrane domain acts as a master regulator guarding cadherin stability. © 2017 Nanes et al. This article is distributed by The American Society for Cell Biology under license from the author(s). Two months after publication it is available to the public under an Attribution–Noncommercial–Share Alike 3.0 Unported Creative Commons License (http://creativecommons.org/licenses/by-nc-sa/3.0).

  11. Deficient autologous mixed lymphocyte reaction in Kaposi's sarcoma associated with deficiency of Leu-3+ responder T cells.

    PubMed Central

    Gupta, S; Safai, B

    1983-01-01

    Autologous mixed lymphocyte reaction (AMLR) and T cell subsets defined with monoclonal antibodies were analyzed in the peripheral blood of homosexual males with Kaposi's sarcoma (KS). All seven patients demonstrated decreased AMLR (P less than 0.001) when compared with age- and sex-matched simultaneously studied controls. These patients also showed decreased proportions of Leu-3+ (helper/inducer phenotype) and an increase in the proportion of Leu-2+ (suppressor/cytotoxic phenotype) T cells. Leu-3+ T cells were purified from two patients by depleting Leu-2+ T cells in complement-dependent cytotoxicity. Leu-3+ T cells from both patients demonstrated poor proliferative response in the AMLR. In allogeneic MLR, patients' T cells were poor responders and their non-T cells were poor stimulators against healthy controls. This study demonstrates deficiency of both AMLR and allogeneic MLR in patients with KS. The decreased AMLR is associated with qualitative and functional deficiency of Leu-3+ responder T cells. Whether the functional deficiency of Leu-3+ responder T cells in the AMLR is a general phenomena or a feature of a subset of patients with KS remains to be determined. PMID:6218186

  12. Cyclooxygenase-2-prostaglandin E2-eicosanoid receptor inflammatory axis: a key player in Kaposi's sarcoma-associated herpes virus associated malignancies.

    PubMed

    Paul, Arun George; Chandran, Bala; Sharma-Walia, Neelam

    2013-08-01

    The role of cyclooxygenase-2 (COX-2), its lipid metabolite prostaglandin E2 (PGE2), and Eicosanoid (EP) receptors (EP; 1-4) underlying the proinflammatory mechanistic aspects of Burkitt's lymphoma, nasopharyngeal carcinoma, cervical cancer, prostate cancer, colon cancer, and Kaposi's sarcoma (KS) is an active area of investigation. The tumorigenic potential of COX-2 and PGE2 through EP receptors forms the mechanistic context underlying the chemotherapeutic potential of nonsteroidal anti-inflammatory drugs (NSAIDs). Although role of the COX-2 is described in several viral associated malignancies, the biological significance of the COX-2/PGE2/EP receptor inflammatory axis is extensively studied only in Kaposi's sarcoma-associated herpes virus (KSHV/HHV-8) associated malignancies such as KS, a multifocal endothelial cell tumor and primary effusion lymphoma (PEL), a B cell-proliferative disorder. The purpose of this review is to summarize the salient findings delineating the molecular mechanisms downstream of COX-2 involving PGE2 secretion and its autocrine and paracrine interactions with EP receptors (EP1-4), COX-2/PGE2/EP receptor signaling regulating KSHV pathogenesis and latency. KSHV infection induces COX-2, PGE2 secretion, and EP receptor activation. The resulting signal cascades modulate the expression of KSHV latency genes (latency associated nuclear antigen-1 [LANA-1] and viral-Fas (TNFRSF6)-associated via death domain like interferon converting enzyme-like- inhibitory protein [vFLIP]). vFLIP was also shown to be crucial for the maintenance of COX-2 activation. The mutually interdependent interactions between viral proteins (LANA-1/vFLIP) and COX-2/PGE2/EP receptors was shown to play key roles in the biological mechanisms involved in KS and PEL pathogenesis such as blockage of apoptosis, cell cycle regulation, transformation, proliferation, angiogenesis, adhesion, invasion, and immune-suppression. Understanding the COX-2/PGE2/EP axis is very important to

  13. Piracy of prostaglandin E2/EP receptor-mediated signaling by Kaposi's sarcoma-associated herpes virus (HHV-8) for latency gene expression: strategy of a successful pathogen.

    PubMed

    George Paul, Arun; Sharma-Walia, Neelam; Kerur, Nagaraj; White, Carl; Chandran, Bala

    2010-05-01

    Kaposi's sarcoma-associated herpes virus (KSHV) is implicated in the pathogenesis of KS, a chronic inflammation-associated malignancy. Cyclooxygenase-2 (COX-2) and its metabolite prostaglandin E2 (PGE2), two pivotal proinflammatory/oncogeneic molecules, are proposed to play roles in the expression of major KSHV latency-associated nuclear antigen-1 (LANA-1). Microsomal PGE2 synthase, PGE2, and its receptors (EP1, EP2, EP3, and EP4) were detected in KS lesions with the distinct staining of EP2/EP4 in KS lesions. In latently infected endothelial TIVE-LTC cells, EP receptor antagonists downregulated LANA-1 expression as well as Ca(2+), p-Src, p-PI3K, p-PKCzeta/lambda, and p-NF-kappaB, which are also some of the signal molecules proposed to be important in KS pathogenesis. Exogenous PGE2 and EP receptor agonists induced the LANA-1 promoter in 293 cells, and YY1, Sp1, Oct-1, Oct-6, C/EBP, and c-Jun transcription factors seem to be involved in this induction. PGE2/EP receptor-induced LANA-1 promoter activity was downregulated significantly by the inhibition of Ca(2+), p-Src, p-PI3K, p-PKCzeta/lambda, and p-NF-kappaB. These findings implicate the inflammatory PGE2/EP receptors and the associated signal molecules in herpes virus latency and uncover a novel paradigm that shows the evolution of KSHV genome plasticity to use inflammatory response for its survival advantage of maintaining latent gene expression. These data also suggest that potential use of anti-COX-2 and anti-EP receptor therapy may not only ameliorate the chronic inflammation associated with KS but could also lead to elimination of the KSHV latent infection and the associated KS lesions.

  14. Kaposi’s Sarcoma-Associated Herpesvirus K3 and K5 Proteins Down Regulate Both DC-SIGN and DC-SIGNR

    PubMed Central

    Karki, Roshan; Tartell, Michael A.; Means, Robert E.

    2013-01-01

    Kaposi’s sarcoma-associated herpesvirus (KSHV) is the etiological agent of multicentric Castleman’s disease, primary effusion lymphoma and Kaposi’s sarcoma. In this study, we show that like the C-type lectin DC-SIGN, the closely related DC-SIGNR can also enhance KSHV infection. Following infection, they are both targeted for down modulation and our data indicate that the KSHV MARCH-family ubiquitin ligase K5 is mediating this regulation and subsequent targeting for degradation of DC-SIGN and DC-SIGNR in the context of the virus. The closely related viral K3 protein, is also able to target these lectins in exogenous expressions studies, but only weakly during viral infection. In addition to requiring a functional RING-CH domain, several protein trafficking motifs in the C-terminal region of both K3 and K5 are important in regulation of DC-SIGN and DC-SIGNR. Further exploration of this modulation revealed that DC-SIGN is endocytosed from the cell surface in THP-1 monocytes, but degraded from an internal location with minimal endocytosis in HEK-293 cells. Pull-down data indicate that both K3 and K5 preferentially associate with immature forms of the lectins, mediating their ubiquitylation and degradation. Together, these data emphasize the molecular complexities of K3 and K5, while expanding the repertoire of targets of these two viral proteins. PMID:23460925

  15. Human herpesvirus 8 open reading frame 26 and open reading frame 65 sequences from multiple myeloma patients: a shared pattern not found in Kaposi's sarcoma or primary effusion lymphoma.

    PubMed

    Ma, H J; Sjak-Shie, N N; Vescio, R A; Kaminsky, M; Mikail, A; Pold, M; Parker, K; Beksac, M; Belson, D; Moss, T J; Wu, C H; Zhou, J; Zhang, L; Chen, G; Said, J W; Berenson, J R

    2000-11-01

    Human herpesvirus 8 (HHV-8), also known as Kaposi's sarcoma-associated herpesvirus, has been implicated in the pathogenesis of Kaposi's sarcoma (KS), primary effusion lymphoma (PEL), multicentric Castleman's disease, and recently multiple myeloma (MM). DNA sequence analyses of HHV-8 suggest that multiple HHV-8 strains exist. We extracted DNA from 24 patients with MM and 3 patients with monoclonal gammopathy of undetermined significance and compared HHV-8 open reading frames (ORFs) 26 and 65 sequences with those derived from patients with KS, PEL, and two HHV-8-positive PEL cell lines KS-1 and BC-1. ORF26 sequence data suggest that MM patients are consistently carriers of HHV-8 strain subtype C3. All MM patients also consistently revealed either a single bp deletion or substitution at position 112197 in ORF65. This unique alteration is not present in patients with KS or PEL or in PEL cell lines. It occurs in the portion of ORF65 that is known to be responsible for a serological response to HHV-8.

  16. The Kaposi Sarcoma Herpesvirus Latency-associated Nuclear Antigen DNA Binding Domain Dorsal Positive Electrostatic Patch Facilitates DNA Replication and Episome Persistence.

    PubMed

    Li, Shijun; Tan, Min; Juillard, Franceline; Ponnusamy, Rajesh; Correia, Bruno; Simas, J Pedro; Carrondo, Maria A; McVey, Colin E; Kaye, Kenneth M

    2015-11-20

    Kaposi sarcoma-associated herpesvirus (KSHV) has a causative role in several human malignancies. KSHV latency-associated nuclear antigen (LANA) mediates persistence of viral episomes in latently infected cells. LANA mediates KSHV DNA replication and segregates episomes to progeny nuclei. The structure of the LANA DNA binding domain was recently solved, revealing a positive electrostatic patch opposite the DNA binding surface, which is the site of BET protein binding. Here we investigate the functional role of the positive patch in LANA-mediated episome persistence. As expected, LANA mutants with alanine or glutamate substitutions in the central, peripheral, or lateral portions of the positive patch maintained the ability to bind DNA by EMSA. However, all of the substitution mutants were deficient for LANA DNA replication and episome maintenance. Mutation of the peripheral region generated the largest deficiencies. Despite these deficiencies, all positive patch mutants concentrated to dots along mitotic chromosomes in cells containing episomes, similar to LANA. The central and peripheral mutants, but not the lateral mutants, were reduced for BET protein interaction as assessed by co-immunoprecipitation. However, defects in BET protein binding were independent of episome maintenance function. Overall, the reductions in episome maintenance closely correlated with DNA replication deficiencies, suggesting that the replication defects account for the reduced episome persistence. Therefore, the electrostatic patch exerts a key role in LANA-mediated DNA replication and episome persistence and may act through a host cell partner(s) other than a BET protein or by inducing specific structures or complexes.

  17. Functional characterization of Kaposi's sarcoma-associated herpesvirus small capsid protein by bacterial artificial chromosome-based mutagenesis

    SciTech Connect

    Sathish, Narayanan; Yuan Yan

    2010-11-25

    A systematic investigation of interactions amongst KSHV capsid proteins was undertaken in this study to comprehend lesser known KSHV capsid assembly mechanisms. Interestingly the interaction patterns of the KSHV small capsid protein, ORF65 suggested its plausible role in viral capsid assembly pathways. Towards further understanding this, ORF65-null recombinant mutants (BAC-{Delta}65 and BAC-stop65) employing a bacterial artificial chromosome (BAC) system were generated. No significant difference was found in both overall viral gene expression and lytic DNA replication between stable monolayers of 293T-BAC36 (wild-type) and 293T-BAC-ORF65-null upon induction with 12-O-tetradecanoylphorbol-13-acetate, though the latter released 30-fold fewer virions to the medium than 293T-BAC36 cells. Sedimentation profiles of capsid proteins of ORF65-null recombinant mutants were non-reflective of their organization into the KSHV capsids and were also undetectable in cytoplasmic extracts compared to noticeable levels in nuclear extracts. These observations collectively suggested the pivotal role of ORF65 in the KSHV capsid assembly processes.

  18. Kaposi’s Sarcoma-Associated Herpesvirus Genome Programming during the Early Stages of Primary Infection of Peripheral Blood Mononuclear Cells

    PubMed Central

    Jha, Hem C.; Lu, Jie; Verma, Subhash C.; Banerjee, Shuvomoy; Mehta, Devan

    2014-01-01

    ABSTRACT The early period of Kaposi’s sarcoma-associated herpesvirus (KSHV) infection involves the dynamic expression of viral genes, which are temporally and epigenetically regulated. KSHV can effectively infect and persist in endothelial as well as human B cells with different gene expression patterns. To understand the temporal epigenetic changes which occur when KSHV infects the lymphocytic compartment, we infected human peripheral blood mononuclear cells (PBMCs) and comprehensively analyzed the changes which occurred at the binding sites of virally encoded lytic as well as latent proteins along with epigenetic modifications across the KSHV genome during early primary infection. Using chromatin immunoprecipitation (ChIP) assays, we showed that the KSHV genome acquires a uniquely distinct histone modification pattern of methylation (H3K4me3, H3K9me3, and H3K27me3) and acetylation (H3Ac) during de novo infection of human PBMCs. This pattern showed that the epigenetic changes were temporally controlled. The binding profiles of KSHV latent protein LANA and the immediate early proteins RTA and K8 showed specific patterns at different times postinfection, which reflects the gene expression program. Further analysis demonstrated that KSHV can concurrently express lytic and latent genes which were associated with histone modifications at these specific regions on the viral genome. We identified three KSHV genes, K3, ORF49, and ORF64, which exhibited different profiles of histone modifications during the early stages of PBMC infection. These studies established a distinct pattern of epigenetic modification which correlates with viral gene expression temporally regulated during the first 7 days of PBMC infection and provides clues to the regulatory program required for successful infection by KSHV of human PBMCs. PMID:25516617

  19. Polymerase Chain Reaction Detection of Kaposi’s Sarcoma-Associated Herpesvirus-Optimized Protocols and Their Application to Myeloma

    PubMed Central

    Pan, Langxing; Milligan, Laura; Michaeli, Joseph; Cesarman, Ethel; Knowles, Daniel M.

    2001-01-01

    Since its discovery in 1994, KSHV (also called human herpesvirus-8 or HHV8) has been implicated in a variety of disorders. Although the association of KSHV with Kaposi’s sarcoma (KS), primary effusion lymphoma (PEL), and multicentric Castleman’s disease has been well established, its presence in some other diseases, such as multiple myeloma, remains controversial. Because most KSHV studies are based on polymerase chain reaction (PCR) analysis, the conflicting data may be attributable to variations in the methods, primer sets, and target sequences selected. To establish an efficient and reliable PCR approach for KSHV detection we designed eight sets of primers to six regions (ORFK1, ORFK2, ORFK9, ORK26, ORF72, and ORF74) of the KSHV genome using appropriate database and software. The detection sensitivity of these primers was carefully assessed and their reliability was strictly validated in a series of positive (15 KS and PEL samples) and negative (16 lymphoid tissues) controls. We found that primer sets to the ORFK9 region showed the highest sensitivity, whereas primer sets to ORFK1 and ORF74 showed the lowest sensitivity. Primer sets to ORFK9, ORF26 and ORF72 regions detected all of the positive cases, whereas other primer sets showed varying detection rates or nonspecific bands. All 16 negative controls were negative with all primer sets. However, six of 16 negative controls became positive when we used nested PCR targeting ORF26. Therefore, multiple target KSHV sequences increase the detection efficiency, while nested PCR protocols are likely to introduce false positivity. Using ORFK9, ORF26 and ORF72 primer sets, we screened bone marrow biopsies from 18 cases of multiple myeloma, and failed to detect any KSHV sequences. This finding supports the conclusion that KSHV is not associated with multiple myeloma. Indeed, our results further confirm that although KSHV is universally present in Kaposi’s sarcoma and primary effusion lymphoma, it is not ubiquitous

  20. Next-Generation Sequence Analysis of the Genome of RFHVMn, the Macaque Homolog of Kaposi's Sarcoma (KS)-Associated Herpesvirus, from a KS-Like Tumor of a Pig-Tailed Macaque

    PubMed Central

    Bruce, A. Gregory; Ryan, Jonathan T.; Thomas, Mathew J.; Peng, Xinxia; Grundhoff, Adam; Tsai, Che-Chung

    2013-01-01

    The complete sequence of retroperitoneal fibromatosis-associated herpesvirus Macaca nemestrina (RFHVMn), the pig-tailed macaque homolog of Kaposi's sarcoma-associated herpesvirus (KSHV), was determined by next-generation sequence analysis of a Kaposi's sarcoma (KS)-like macaque tumor. Colinearity of genes was observed with the KSHV genome, and the core herpesvirus genes had strong sequence homology to the corresponding KSHV genes. RFHVMn lacked homologs of open reading frame 11 (ORF11) and KSHV ORFs K5 and K6, which appear to have been generated by duplication of ORFs K3 and K4 after the divergence of KSHV and RFHV. RFHVMn contained positional homologs of all other unique KSHV genes, although some showed limited sequence similarity. RFHVMn contained a number of candidate microRNA genes. Although there was little sequence similarity with KSHV microRNAs, one candidate contained the same seed sequence as the positional homolog, kshv-miR-K12-10a, suggesting functional overlap. RNA transcript splicing was highly conserved between RFHVMn and KSHV, and strong sequence conservation was noted in specific promoters and putative origins of replication, predicting important functional similarities. Sequence comparisons indicated that RFHVMn and KSHV developed in long-term synchrony with the evolution of their hosts, and both viruses phylogenetically group within the RV1 lineage of Old World primate rhadinoviruses. RFHVMn is the closest homolog of KSHV to be completely sequenced and the first sequenced RV1 rhadinovirus homolog of KSHV from a nonhuman Old World primate. The strong genetic and sequence similarity between RFHVMn and KSHV, coupled with similarities in biology and pathology, demonstrate that RFHVMn infection in macaques offers an important and relevant model for the study of KSHV in humans. PMID:24109218

  1. Kaposi's sarcoma herpesvirus and HIV-1 seroprevalences in prostitutes in Djibouti.

    PubMed

    Marcelin, Anne-Geneviève; Grandadam, Marc; Flandre, Philippe; Nicand, Elisabeth; Milliancourt, Catherine; Koeck, Jean-Louis; Philippon, Michel; Teyssou, Remy; Agut, Henri; Dupin, Nicolas; Calvez, Vincent

    2002-10-01

    Kaposi's sarcoma herpesvirus (KSHV) is linked causally to Kaposi's sarcoma. Epidemiological studies have shown that KSHV transmission can occur during sex among homosexual men, but heterosexual transmission seems to be very rare in KSHV low prevalence countries. A seroepidemiological study was conducted to determine whether KSHV is transmitted sexually between heterosexuals in an endemic country. Sera from 282 subjects of African origin living in Djibouti were tested for antibodies to KSHV and HIV-1. Among the 282 individuals, 43 were female prostitutes working in the streets (group 1), 123 were female prostitutes working in luxury bars (group 2), 41 were non-prostitute females (group 3), and 75 were non-prostitute males (group 4). KSHV seroprevalence was 26, 20, 17, and 36% in groups 1, 2, 3, and 4, respectively. The seroprevalence of KSHV is not different between street or bar prostitutes and non-prostitute females (OR = 1.67; P = 0.34 and OR = 1.18; P = 0.73). These results suggest that in this endemic country commercial sex work does not seem to be a risk factor for KSHV infection and provides evidence against heterosexual transmission of KSHV in the female population studied.

  2. Ser-634 and Ser-636 of Kaposi’s Sarcoma-Associated Herpesvirus RTA are Involved in Transactivation and are Potential Cdk9 Phosphorylation Sites

    PubMed Central

    Tsai, Wan-Hua; Wang, Pei-Wen; Lin, Shu-Yu; Wu, I-Lin; Ko, Ying-Chieh; Chen, Yu-Lian; Li, Mengtao; Lin, Su-Fang

    2011-01-01

    The replication and transcription activator (RTA) of Kaposi’s sarcoma-associated herpesvirus (KSHV), K-RTA, is a lytic switch protein that moderates the reactivation process of KSHV latency. By mass spectrometric analysis of affinity purified K-RTA, we showed that Thr-513 or Thr-514 was the primary in vivo phosphorylation site. Thr-513 and Thr-514 are proximal to the nuclear localization signal (527KKRK530) and were previously hypothesized to be target sites of Ser/Thr kinase hKFC. However, substitutions of Thr with Ala at 513 and 514 had no effect on K-RTA subcellular localization or transactivation activity. By contrast, replacement of Ser with Ala at Ser-634 and Ser-636 located in a Ser/Pro-rich region of K-RTA, designated as S634A/S636A, produced a polypeptide with ∼10 kDa shorter in molecular weight and reduced transactivation in a luciferase reporter assay relative to the wild type. In contrast to prediction, the decrease in molecular weight was not due to lack of phosphorylation because the overall Ser and Thr phosphorylation state in K-RTA and S634A/S636A were similar, excluding that Ser-634 or Ser-636 motif served as docking sites for consecutive phosphorylation. Interestingly, S634A/S636A lost ∼30% immuno-reactivity to MPM2, an antibody specific to pSer/pThr-Pro motif, indicating that 634SPSP637 motif was in vivo phosphorylated. By in vitro kinase assay, we showed that K-RTA is a substrate of CDK9, a Pro-directed Ser/Thr kinase central to transcriptional regulation. Importantly, the capability of K-RTA in associating with endogenous CDK9 was reduced in S634A/S636A, which suggested that Ser-634 and Ser-636 may be involved in CDK9 recruitment. In agreement, S634A/S636A mutant exhibited ∼25% reduction in KSHV lytic cycle reactivation relative to that by the wild type K-RTA. Taken together, our data propose that Ser-634 and Ser-636 of K-RTA are phosphorylated by host transcriptional kinase CDK9 and such a process contributes to a full

  3. ESCRT-I Protein Tsg101 Plays a Role in the Post-macropinocytic Trafficking and Infection of Endothelial Cells by Kaposi’s Sarcoma-Associated Herpesvirus

    PubMed Central

    Kumar, Binod; Dutta, Dipanjan; Iqbal, Jawed; Ansari, Mairaj Ahmed; Roy, Arunava; Chikoti, Leela; Pisano, Gina; Veettil, Mohanan Valiya; Chandran, Bala

    2016-01-01

    Kaposi’s sarcoma-associated herpesvirus (KSHV) binding to the endothelial cell surface heparan sulfate is followed by sequential interactions with α3β1, αVβ3 and αVβ5 integrins and Ephrin A2 receptor tyrosine kinase (EphA2R). These interactions activate host cell pre-existing FAK, Src, PI3-K and RhoGTPase signaling cascades, c-Cbl mediated ubiquitination of receptors, recruitment of CIB1, p130Cas and Crk adaptor molecules, and membrane bleb formation leading to lipid raft dependent macropinocytosis of KSHV into human microvascular dermal endothelial (HMVEC-d) cells. The Endosomal Sorting Complexes Required for Transport (ESCRT) proteins, ESCRT-0, -I, -II, and–III, play a central role in clathrin-mediated internalized ubiquitinated receptor endosomal trafficking and sorting. ESCRT proteins have also been shown to play roles in viral egress. We have recently shown that ESCRT-0 component Hrs protein associates with the plasma membrane during macropinocytosis and mediates KSHV entry via ROCK1 mediated phosphorylation of NHE1 and local membrane pH change. Here, we demonstrate that the ESCRT-I complex Tsg101 protein also participates in the macropinocytosis of KSHV and plays a role in KSHV trafficking. Knockdown of Tsg101 did not affect virus entry in HMVEC-d and human umbilical vein endothelial (HUVEC) cells but significantly inhibited the KSHV genome entry into the nucleus and consequently viral gene expression in these cells. Double and triple immunofluorescence, proximity ligation immunofluorescence and co-immuoprecipitation studies revealed the association of Tsg101 with the KSHV containing macropinosomes, and increased levels of Tsg101 association/interactions with EphA2R, c-Cbl, p130Cas and Crk signal molecules, as well as with upstream and downstream ESCRT components such as Hrs (ESCRT-0), EAP45 (ESCRT-II), CHMP6 (ESCRT-III) and CHMP5 (ESCRT-III) in the KSHV infected cells. Tsg101 was also associated with early (Rab5) and late endosomal (Rab7) stages of

  4. mTOR inhibitors block Kaposi sarcoma growth by inhibiting essential autocrine growth factors and tumor angiogenesis.

    PubMed

    Roy, Debasmita; Sin, Sang-Hoon; Lucas, Amy; Venkataramanan, Raman; Wang, Ling; Eason, Anthony; Chavakula, Veenadhari; Hilton, Isaac B; Tamburro, Kristen M; Damania, Blossom; Dittmer, Dirk P

    2013-04-01

    Kaposi sarcoma originates from endothelial cells and it is one of the most overt angiogenic tumors. In Sub-Saharan Africa, where HIV and the Kaposi sarcoma-associated herpesvirus (KSHV) are endemic, Kaposi sarcoma is the most common cancer overall, but model systems for disease study are insufficient. Here, we report the development of a novel mouse model of Kaposi sarcoma, where KSHV is retained stably and tumors are elicited rapidly. Tumor growth was sensitive to specific allosteric inhibitors (rapamycin, CCI-779, and RAD001) of the pivotal cell growth regulator mTOR. Inhibition of tumor growth was durable up to 130 days and reversible. mTOR blockade reduced VEGF secretion and formation of tumor vasculature. Together, the results show that mTOR inhibitors exert a direct anti-Kaposi sarcoma effect by inhibiting angiogenesis and paracrine effectors, suggesting their application as a new treatment modality for Kaposi sarcoma and other cancers of endothelial origin.

  5. Relationship between human herpesvirus 8 loads and disease stage in classic Kaposi sarcoma patients.

    PubMed

    Guttman-Yassky, Emma; Abada, Rinat; Kra-Oz, Zipi; Sattinger, Judith; Perelman, Alex; Bergman, Reuven; Sarid, Ronit

    2007-04-01

    Human herpesvirus 8 (HHV-8), also known as Kaposi sarcoma (KS)-associated herpesvirus, is causally implicated in all forms of KS, including the classic form. Our objective was to investigate the relationship between HHV-8 load in peripheral blood mononuclear cells (PBMCs) and the stage of the disease in classic KS (CKS) patients. HHV-8 loads were measured in 41 PBMC samples from CKS patients with different Krigel-based classification stages using a quantitative real-time polymerase chain reaction assay. Low HHV-8 DNA loads reaching a maximum of 75.5 copies/10(5) cells were detected in 73.2% of the patients. HHV-8 loads in patients with stages I and II were similarly distributed. An increased detection rate of HHV-8 DNA, although not statistically significant, was evident in patients diagnosed with CKS stages III and IV. We conclude that the measurements of HHV-8 load in PBMCs provide a limited correlation with the clinical stage of KS.

  6. HIV-associated Kaposi sarcoma and related diseases.

    PubMed

    Gonçalves, Priscila H; Uldrick, Thomas S; Yarchoan, Robert

    2017-09-10

    : The search for the etiologic agent for Kaposi sarcoma led to the discovery of Kaposi sarcoma-associated herpesvirus (KSHV) in 1994. KSHV, also called human herpesvirus-8, has since been shown to be the etiologic agent for several other tumors and diseases, including primary effusion lymphoma (PEL), an extracavitary variant of PEL, KSHV-associated diffuse large B-cell lymphoma, a form of multicentric Castleman disease, and KSHV inflammatory cytokine syndrome. KSHV encodes several genes that interfere with innate and specific immunity, thwart apoptosis, enhance cell proliferation and cytokine production, and promote angiogenesis, and these play important roles in disease pathogenesis. HIV is an important cofactor in Kaposi sarcoma pathogenesis, and widespread use of antiretroviral therapy has reduced Kaposi sarcoma incidence. However, Kaposi sarcoma remains the second most frequent tumor arising in HIV-infected patients in the United States and is particularly common in sub-Saharan Africa. KSHV prevalence varies substantially in different populations. KSHV is secreted in saliva, and public health measures to reduce its spread may help reduce the incidence of KSHV-associated diseases. Although there have been advances in the treatment of Kaposi sarcoma, KSHV-multicentric Castleman disease, and PEL, improved therapies are needed, especially those that are appropriate for Kaposi sarcoma in resource-poor regions.

  7. Glycyrrhizic acid alters Kaposi sarcoma–associated herpesvirus latency, triggering p53-mediated apoptosis in transformed B lymphocytes

    PubMed Central

    Curreli, Francesca; Friedman-Kien, Alvin E.; Flore, Ornella

    2005-01-01

    Kaposi sarcoma–associated herpesvirus (KSHV) is linked with all clinical forms of Kaposi sarcoma and several lymphoproliferative disorders. Like other herpesviruses, KSHV becomes latent in the infected cells, expressing only a few genes that are essential for the establishment and maintenance of its latency and for the survival of the infected cells. Inhibiting the expression of these latent genes should lead to eradication of herpesvirus infection. All currently available drugs are ineffective against latent infection. Here we show, for the first time to our knowledge, that latent infection with KSHV in B lymphocytes can be terminated by glycyrrhizic acid (GA), a triterpenoid compound earlier shown to inhibit the lytic replication of other herpesviruses. We demonstrate that GA disrupts latent KSHV infection by downregulating the expression of latency-associated nuclear antigen (LANA) and upregulating the expression of viral cyclin and selectively induces cell death of KSHV-infected cells. We show that reduced levels of LANA lead to p53 reactivation, an increase in ROS, and mitochondrial dysfunction, which result in G1 cell cycle arrest, DNA fragmentation, and oxidative stress–mediated apoptosis. Latent genes are involved in KSHV-induced oncogenesis, and strategies to interfere with their expression might prove useful for eradicating latent KSHV infection and have future therapeutic implications. PMID:15765147

  8. Genotypic analysis at multiple loci across Kaposi's sarcoma herpesvirus (KSHV) DNA molecules: clustering patterns, novel variants and chimerism.

    PubMed

    Zong, Jianchao; Ciufo, Dolores M; Viscidi, Raphael; Alagiozoglou, Lee; Tyring, Stephen; Rady, Peter; Orenstein, Jan; Boto, William; Kalumbuja, Henry; Romano, Nino; Melbye, Mads; Kang, Gyeong H; Boshoff, Chris; Hayward, Gary S

    2002-01-01

    The genomes of human Kaposi's sarcoma-associated herpesvirus (KSHV) display several levels of DNA sequence heterogeneity and subgrouping that show distinctive clustering patterns in related human populations. The four major subtype patterns for the hypervariable ORF-K1 protein correlate closely with the principal diasporas resulting from the migration of modern humans out of East Africa and suggest that KSHV is an ancient human virus that is transmitted primarily in a familial fashion with consequent very low recombination rates. However, chimeric genomes have also been detected, especially with regard to the presence of P versus M alleles of the ORF-K15 gene. To understand further the genetic organization and evolutionary history of KSHV, especially with regard to possible new subtypes, recombinant genomes, constant region loci and clustering in particular ethnic groups or among classic versus epidemic cases in the same geographic area. Direct PCR DNA sequencing was carried out on the ORF-K1 and ORF-K15 genes at the extreme left and right hand sides, as well as on six other internal loci of diagnostic samples collected from 70 new KSHV-positive patients in Israel, South Korea, Sicily, Scandinavia, Brazil, Uganda, South Africa and the US. Our overall results from more than 135 KSHV genomes from many different human population groups now provides evidence for seven distinct subtypes of KSHV genomes (referred to as A/P, B/P, C/P, D/P, M, N and Q). However, the two most closely related subtypes (A/P and C/P) are only differentiated at the LHS side of the genome, and the three most distantly related forms (M, N and Q) appear to exist only as small chimeric segments that are remnants from the RHS of more ancient forms of the virus. By analyzing multiple conserved loci across the B subtype genomes that predominate in sub-Saharan Africa, we can also now recognize three to four distinct B genome subgroups with varying patterns of inter and intratypic mosaicism. Analysis of

  9. Risk Factors for Seropositivity to Kaposi Sarcoma–Associated Herpesvirus Among Children in Uganda

    PubMed Central

    Webb, Emily L.; Sebina, Ismail; Nalwoga, Angela; Muhangi, Lawrence; Miley, Wendell; Johnston, W. Thomas; Ndibazza, Juliet; Whitby, Denise; Newton, Robert; Elliott, Alison M.

    2013-01-01

    Background: Determinants of Kaposi sarcoma–associated herpesvirus (KSHV) seropositivity among children living in sub-Saharan African populations where infection is endemic are not well understood. Local environmental factors, including other infectious agents, may be key. Methods: Within the context of a well-characterized birth cohort, we examined associations between various factors and antibodies against KSHV, measured in stored plasma samples from 1823 mother–child pairs in Entebbe, Uganda. Results: Seroprevalence increased with increasing age of the child (P = 0.0003) and was higher among those with KSHV seropositive mothers than in those without (12% vs 9%; odds ratio: 1.4, 95% confidence interval: 1.1 to 2.0). It was also higher among children with HIV infection (29% vs 10%; odds ratio: 3.1, 95% confidence interval: 1.2 to 8.3) or malaria parasitemia (30% vs 10%; odds ratio: 4.1, 95% confidence interval: 2.4 to 7.0) than in children without. These associations were not explained by socioeconomic status. Conclusions: The finding that KSHV serostatus is associated with malaria parasitemia in children is novel. In a country endemic for KSHV, malaria may be a cofactor for KSHV infection or reactivation among children. PMID:23403859

  10. Cancers associated with Kaposi's sarcoma (KS) in AIDS: a link between KS herpesvirus and immunoblastic lymphoma

    PubMed Central

    Engels, E A; Rosenberg, P S; Frisch, M; Goedert, J J

    2001-01-01

    Kaposi's sarcoma (KS), common among persons with acquired immunodeficiency syndrome (AIDS), is caused by KS herpesvirus (KSHV) but whether KSHV causes other malignancies is uncertain. Using linked United States AIDS and cancer registries, we measured the incidence of specific malignancies in persons with AIDS (4–27 months after AIDS onset). We identified associations with KSHV by calculating a relative risk: cancer incidence in persons with KS (all were KSHV-infected) divided by incidence in persons without KS. Using Poisson regression, relative risks were adjusted for human immunodeficiency virus risk group, gender, age, race, and calendar year. We included 189 159 subjects (26 972 with KS). Immunoblastic lymphoma was significantly associated with KS (506 cases; relative risks: unadjusted 2.44, 95%CI 2.00–2.96, adjusted 1.58, 95%CI 1.29–1.93). Only one immunoblastic lymphoma had pleura as primary site. None of 37 other specified malignancies (other non-Hodgkin lymphomas, haematological malignancies, solid tumours) was significantly associated with KS. In summary, the association of immunoblastic lymphoma with KS was specific among examined malignancies and remained significant after statistical adjustment. Our findings, and the previously demonstrated presence of KSHV in the histologically related primary effusion lymphoma, suggest that KSHV is involved in the pathogenesis of some immunoblastic lymphomas. © 2001 Cancer Research Campaign PMID:11720464

  11. The latency-associated nuclear antigen of Kaposi sarcoma–associated herpesvirus induces B cell hyperplasia and lymphoma

    PubMed Central

    Fakhari, Farnaz D.; Jeong, Joseph H.; Kanan, Yogita; Dittmer, Dirk P.

    2006-01-01

    Kaposi sarcoma–associated herpesvirus (KSHV) is a human lymphotropic herpesvirus. It is implicated in B cell neoplasias such as primary effusion lymphoma and multicentric Castleman disease in AIDS patients. The KSHV latency-associated nuclear antigen (LANA) is consistently expressed in all KSHV-associated tumor cells and was shown to bind the tumor suppressor proteins p53 and pRb. To test LANA’s contribution to lymphomagenesis in vivo we generated transgenic mice expressing LANA under the control of its own promoter, which is B cell specific. All of the transgenic mice developed splenic follicular hyperplasia due to an expansion of IgM+IgD+ B cells and showed increased germinal center formation. We also observed lymphomas, implying that LANA can activate B cells and provide the first step toward lymphomagenesis. PMID:16498502

  12. Human herpesvirus 8-encoded cytokines.

    PubMed

    Nicholas, John

    2010-03-01

    Human herpesvirus (HHV)-8, also called Kaposi's sarcoma-associated herpesvirus, was discovered in 1994 and was rapidly sequenced, revealing several unique and surprising features of its genetic makeup. Among these discoveries was the identification of the first viral homolog of IL-6 and three CC/beta-chemokine ligands (viral CCL-1, -2 and -3), not previously found in gamma-herpesviruses. Viral IL-6 was immediately recognized as a potential contributor to HHV-8 pathogenesis, specifically endothelial-derived Kaposi's sarcoma and the B-cell malignancy multicentric Castleman's disease with which IL-6, a proangiogenic and B-cell growth factor, had previously been implicated. The roles of the viral chemokines were speculated to involve immune evasion; however, like viral IL-6, the viral chemokines have the potential to contribute to pathogenesis through their shared angiogenic activities, known to be important for Kaposi's sarcoma and HHV-8-associated primary effusion lymphoma, and also via direct prosurvival activities. This article will discuss the molecular properties, activities and functions of viral IL-6 and the viral CCLs, proteins that could provide appropriate targets for antiviral and therapeutic strategies.

  13. Cannabidiol Inhibits Growth and Induces Programmed Cell Death in Kaposi Sarcoma–Associated Herpesvirus-Infected Endothelium

    PubMed Central

    Maor, Yehoshua; Yu, Jinlong; Kuzontkoski, Paula M.; Dezube, Bruce J.; Zhang, Xuefeng

    2012-01-01

    Kaposi sarcoma is the most common neoplasm caused by Kaposi sarcoma–associated herpesvirus (KSHV). It is prevalent among the elderly in the Mediterranean, inhabitants of sub-Saharan Africa, and immunocompromised individuals such as organ transplant recipients and AIDS patients. Current treatments for Kaposi sarcoma can inhibit tumor growth but are not able to eliminate KSHV from the host. When the host’s immune system weakens, KSHV begins to replicate again, and active tumor growth ensues. New therapeutic approaches are needed. Cannabidiol (CBD), a plant-derived cannabinoid, exhibits promising antitumor effects without inducing psychoactive side effects. CBD is emerging as a novel therapeutic for various disorders, including cancer. In this study, we investigated the effects of CBD both on the infection of endothelial cells (ECs) by KSHV and on the growth and apoptosis of KSHV-infected ECs, an in vitro model for the transformation of normal endothelium to Kaposi sarcoma. While CBD did not affect the efficiency with which KSHV infected ECs, it reduced proliferation and induced apoptosis in those infected by the virus. CBD inhibited the expression of KSHV viral G protein–coupled receptor (vGPCR), its agonist, the chemokine growth-regulated protein α (GRO-α), vascular endothelial growth factor receptor 3 (VEGFR-3), and the VEGFR-3 ligand, vascular endothelial growth factor C (VEGF-C). This suggests a potential mechanism by which CBD exerts its effects on KSHV-infected endothelium and supports the further examination of CBD as a novel targeted agent for the treatment of Kaposi sarcoma. PMID:23264851

  14. Probing the Solution Structure of IκB Kinase (IKK) Subunit γ and Its Interaction with Kaposi Sarcoma-associated Herpes Virus Flice-interacting Protein and IKK Subunit β by EPR Spectroscopy.

    PubMed

    Bagnéris, Claire; Rogala, Kacper B; Baratchian, Mehdi; Zamfir, Vlad; Kunze, Micha B A; Dagless, Selina; Pirker, Katharina F; Collins, Mary K; Hall, Benjamin A; Barrett, Tracey E; Kay, Christopher W M

    2015-07-03

    Viral flice-interacting protein (vFLIP), encoded by the oncogenic Kaposi sarcoma-associated herpes virus (KSHV), constitutively activates the canonical nuclear factor κ-light-chain-enhancer of activated B cells (NF-κB) pathway. This is achieved through subversion of the IκB kinase (IKK) complex (or signalosome), which involves a physical interaction between vFLIP and the modulatory subunit IKKγ. Although this interaction has been examined both in vivo and in vitro, the mechanism by which vFLIP activates the kinase remains to be determined. Because IKKγ functions as a scaffold, recruiting both vFLIP and the IKKα/β subunits, it has been proposed that binding of vFLIP could trigger a structural rearrangement in IKKγ conducive to activation. To investigate this hypothesis we engineered a series of mutants along the length of the IKKγ molecule that could be individually modified with nitroxide spin labels. Subsequent distance measurements using electron paramagnetic resonance spectroscopy combined with molecular modeling and molecular dynamics simulations revealed that IKKγ is a parallel coiled-coil whose response to binding of vFLIP or IKKβ is localized twisting/stiffening and not large-scale rearrangements. The coiled-coil comprises N- and C-terminal regions with distinct registers accommodated by a twist: this structural motif is exploited by vFLIP, allowing it to bind and subsequently activate the NF-κB pathway. In vivo assays confirm that NF-κB activation by vFLIP only requires the N-terminal region up to the transition between the registers, which is located directly C-terminal of the vFLIP binding site.

  15. Probing the Solution Structure of IκB Kinase (IKK) Subunit γ and Its Interaction with Kaposi Sarcoma-associated Herpes Virus Flice-interacting Protein and IKK Subunit β by EPR Spectroscopy*

    PubMed Central

    Bagnéris, Claire; Rogala, Kacper B.; Baratchian, Mehdi; Zamfir, Vlad; Kunze, Micha B. A.; Dagless, Selina; Pirker, Katharina F.; Collins, Mary K.; Hall, Benjamin A.; Barrett, Tracey E.; Kay, Christopher W. M.

    2015-01-01

    Viral flice-interacting protein (vFLIP), encoded by the oncogenic Kaposi sarcoma-associated herpes virus (KSHV), constitutively activates the canonical nuclear factor κ-light-chain-enhancer of activated B cells (NF-κB) pathway. This is achieved through subversion of the IκB kinase (IKK) complex (or signalosome), which involves a physical interaction between vFLIP and the modulatory subunit IKKγ. Although this interaction has been examined both in vivo and in vitro, the mechanism by which vFLIP activates the kinase remains to be determined. Because IKKγ functions as a scaffold, recruiting both vFLIP and the IKKα/β subunits, it has been proposed that binding of vFLIP could trigger a structural rearrangement in IKKγ conducive to activation. To investigate this hypothesis we engineered a series of mutants along the length of the IKKγ molecule that could be individually modified with nitroxide spin labels. Subsequent distance measurements using electron paramagnetic resonance spectroscopy combined with molecular modeling and molecular dynamics simulations revealed that IKKγ is a parallel coiled-coil whose response to binding of vFLIP or IKKβ is localized twisting/stiffening and not large-scale rearrangements. The coiled-coil comprises N- and C-terminal regions with distinct registers accommodated by a twist: this structural motif is exploited by vFLIP, allowing it to bind and subsequently activate the NF-κB pathway. In vivo assays confirm that NF-κB activation by vFLIP only requires the N-terminal region up to the transition between the registers, which is located directly C-terminal of the vFLIP binding site. PMID:25979343

  16. Seroprevalence of Human herpesvirus 8 (HHV-8) and incidence of Kaposi's sarcoma in Iran

    PubMed Central

    2011-01-01

    Seroepidemiological surveys show that the prevalence of human herpesvirus 8 (HHV-8) infection mostly varies in various geographical areas and reflects the local incidence of classic and endemic KS, being widespread in sub-Saharan Africa and Mediterranean countries and uncommon in the USA and Northern Europe. In the Middle East only few populations, such as Ashkenazi and Sephardic groups in Israel, have been adequately evaluated for HHV-8 seroprevalence. Among Iranian population a striking higher seroprevalence of HHV8 has been reported among haemodialysis (16.9%), renal transplant recipients (25%) and HIV (45.7%) patients compared to blood donors (2%). Kaposi's sarcoma (KS) is the rarest cancer in Iran, with an annual age-standardized incidence varying from 0.10 to 0.17 per 100,000 in males and from 0.06 to 0.08 per 100,000 in females. KS, however, is one of the most important malignancies in Iranian renal transplanted patients affecting up to 2.4% of organ recipients. The epidemiology of HHV8 and KS in Iran needs further evaluation. While the high prevalence of HHV-8 antibodies in HIV positive and haemodialysis individuals may be attributed to high-risk sexual behavior and polytransfusions, respectively, unknown determinants may be responsible for high seroprevalence of HHV8 and high incidence of KS in solid organ recipients. A global survey on HHV8 seroprevalence in Iran is mandatory to define co-factors associated with HHV8 infection and KS risk in the general Iranian population and in specific patient groups. PMID:21527020

  17. Seroprevalence of Human herpesvirus 8 (HHV-8) and incidence of Kaposi's sarcoma in Iran.

    PubMed

    Jalilvand, Somayeh; Shoja, Zabihollah; Mokhtari-Azad, Talat; Nategh, Rakhshandeh; Gharehbaghian, Ahmad

    2011-04-28

    Seroepidemiological surveys show that the prevalence of human herpesvirus 8 (HHV-8) infection mostly varies in various geographical areas and reflects the local incidence of classic and endemic KS, being widespread in sub-Saharan Africa and Mediterranean countries and uncommon in the USA and Northern Europe. In the Middle East only few populations, such as Ashkenazi and Sephardic groups in Israel, have been adequately evaluated for HHV-8 seroprevalence. Among Iranian population a striking higher seroprevalence of HHV8 has been reported among haemodialysis (16.9%), renal transplant recipients (25%) and HIV (45.7%) patients compared to blood donors (2%). Kaposi's sarcoma (KS) is the rarest cancer in Iran, with an annual age-standardized incidence varying from 0.10 to 0.17 per 100,000 in males and from 0.06 to 0.08 per 100,000 in females. KS, however, is one of the most important malignancies in Iranian renal transplanted patients affecting up to 2.4% of organ recipients. The epidemiology of HHV8 and KS in Iran needs further evaluation. While the high prevalence of HHV-8 antibodies in HIV positive and haemodialysis individuals may be attributed to high-risk sexual behavior and polytransfusions, respectively, unknown determinants may be responsible for high seroprevalence of HHV8 and high incidence of KS in solid organ recipients. A global survey on HHV8 seroprevalence in Iran is mandatory to define co-factors associated with HHV8 infection and KS risk in the general Iranian population and in specific patient groups.

  18. Identification of a Spliced Gene from Kaposi’s Sarcoma-Associated Herpesvirus Encoding a Protein with Similarities to Latent Membrane Proteins 1 and 2A of Epstein-Barr Virus

    PubMed Central

    Glenn, Mark; Rainbow, Lucille; Auradé, Frédéric; Davison, Andrew; Schulz, Thomas F.

    1999-01-01

    Kaposi’s sarcoma-associated herpesvirus (KSHV) or human herpesvirus 8 (HHV-8) is a novel herpesvirus implicated as the causative agent of Kaposi’s sarcoma (KS), primary effusion lymphoma, and some cases of multicentric Castleman’s disease. KSHV persists in the majority of KS spindle (endothelial tumor) cells and lymphoid cells in a latent form, with only a limited set of viral genes expressed in a tissue-specific manner. Here, we report the identification of a family of alternatively-spliced transcripts of approximately 7.5 kb expressed in latently infected body cavity-based lymphoma (BCBL) cell lines which are predicted to encode membrane proteins with similarities to the LMP2A and LMP1 proteins of Epstein-Barr virus. In two highly divergent sequence variants of the right end of the KSHV genome, alternative splicing of eight exons located between KSHV ORF 75 and the terminal repeats yields transcripts appropriate for proteins with up to 12 transmembrane domains, followed by a hydrophilic C-terminal, presumably cytoplasmic, domain. This C-terminal domain contains several YxxI/L motifs reminiscent of LMP2A and a putative TRAF binding site as in LMP1. In latently (persistently) infected BCBL cells the predominant transcript utilizes all eight exons, whereas in phorbol-ester-induced cells, a shorter transcript, lacking exons 4 and 5, is also abundant. We also found evidence for an alternative use of exon 1. Transfection of an epitope-tagged cDNA construct containing all exons indicates that the encoded protein is localized on cell surface and intracellular membranes, and glutathione S-transferase pull-down experiments indicate that its cytoplasmic domain, like that of LMP1, interacts with TRAF1, -2, and -3. Two of 20 KS patients had antibodies to the hydrophilic C-terminal domain, suggesting that the protein is expressed in vivo. PMID:10400794

  19. Serologic association of human herpesvirus eight with posttransplant Kaposi's sarcoma in Saudi Arabia.

    PubMed

    Qunibi, W; Al-Furayh, O; Almeshari, K; Lin, S F; Sun, R; Heston, L; Ross, D; Rigsby, M; Miller, G

    1998-02-27

    In Saudi Arabia, Kaposi's sarcoma occurs in 4.1% of renal transplant recipients and accounts for 70% of malignancies in this group. Human herpes virus 8 (HHV8) has been identified in the DNA of many of these patients. The association between HHV8 and Kaposi's sarcoma was investigated further in post-renal transplant Kaposi's sarcoma patients from a tertiary care hospital (King Faisal Specialist Hospital and Research Center) in Riyadh, Saudi Arabia (n = 14), and non-Kaposi's sarcoma controls with renal transplant (n = 18), chronic renal failure (n = 14), other cancers that did not affect renal function (n = 15), and healthy volunteers (n = 15). The median time from transplant to Kaposi's sarcoma was 13 months. A serum sample was assumed to have antibodies to HHV8 if antibody to either p40 or sVCA was detected. The prevalence of HHV8 seroreactivity was 13/14 (93%) in cases, 5/18 (28%) in renal transplants without Kaposi's sarcoma, and 11/62 (18%) in the aggregate control group. HHV8 seroreactivity was significantly more common (p 0.001) among transplant patients with Kaposi's sarcoma than those without this cancer (odds ratio, 33.80; 95% confidence interval, 2.96-904). These findings suggest an etiologic link between HHV8 and Kaposi's sarcoma presumably due to immunologic or cellular factors that influence host-virus interactions.

  20. Immunohistochemical detection of the latent nuclear antigen-1 of the human herpesvirus type 8 to differentiate cutaneous epidemic Kaposi sarcoma and its histological simulators.

    PubMed

    Pereira, Patricia Fonseca; Cuzzi, Tullia; Galhardo, Maria Clara Gutierrez

    2013-01-01

    Kaposi's sarcoma is the most common neoplasia diagnosed in AIDS patients and the expression of the human herpesvirus-8 (HHV-8) latent nuclear antigen-1 has been useful for its histological diagnosis. The aim of this study is to confirm that immunohistochemistry is a valuable tool for differentiating KS from its simulators in skin biopsies of HIV patients. Immunohistochemical and histological analyses were performed in 49 Kaposi's sarcoma skin biopsies and 60 of its histological simulators. Positivity was present in the 49 Kaposi's sarcoma skin biopsies and no staining was observed in the 60 simulators analyzed, resulting in sensibility and specificity of 100%. HHV-8 immunohistochemical detection is an effective tool for diagnosing Kaposi's sarcoma, especially in early lesions in which neoplastic features are not evident. It also contributes to its histological differential diagnosis.

  1. Independence of Herpesvirus-Induced T Cell Lymphoma from Viral Cyclin D Homologue

    PubMed Central

    Ensser, Armin; Glykofrydes, Diana; Niphuis, Henk; Kuhn, Eva M.; Rosenwirth, Brigitte; Heeney, Jonathan L.; Niedobitek, Gerald; Müller-Fleckenstein, Ingrid; Fleckenstein, Bernhard

    2001-01-01

    Cyclin D family members are cellular protooncogenes, and their viral homologues in the Kaposi's sarcoma-associated herpesvirus (KSHV, human herpesvirus type 8 [HHV-8]) and the closely related Herpesvirus saimiri have been implicated as putative cofactors of viral transformation and pathogenesis. KSHV is regularly found in Kaposi's sarcoma and in the primary effusion B cell lymphoma and Castleman's disease associated with immunosuppression and AIDS. H. saimiri strain C488 transforms human and marmoset T cells in vitro and causes polyclonal T cell lymphoma in New World monkeys. The viral cyclins stimulate cell cycle progression of quiescent fibroblasts, and they form active cyclin-dependent kinase (CDK)6 complexes of broad substrate specificity that can resist and downregulate cellular CDK inhibitors. This study shows that the viral cyclin of H. saimiri strain C488 is not required for viral replication, T cell transformation, and pathogenicity in New World primates. PMID:11238594

  2. Independence of herpesvirus-induced T cell lymphoma from viral cyclin D homologue.

    PubMed

    Ensser, A; Glykofrydes, D; Niphuis, H; Kuhn, E M; Rosenwirth, B; Heeney, J L; Niedobitek, G; Müller-Fleckenstein, I; Fleckenstein, B

    2001-03-05

    Cyclin D family members are cellular protooncogenes, and their viral homologues in the Kaposi's sarcoma-associated herpesvirus (KSHV, human herpesvirus type 8 [HHV-8]) and the closely related Herpesvirus saimiri have been implicated as putative cofactors of viral transformation and pathogenesis. KSHV is regularly found in Kaposi's sarcoma and in the primary effusion B cell lymphoma and Castleman's disease associated with immunosuppression and AIDS. H. saimiri strain C488 transforms human and marmoset T cells in vitro and causes polyclonal T cell lymphoma in New World monkeys. The viral cyclins stimulate cell cycle progression of quiescent fibroblasts, and they form active cyclin-dependent kinase (CDK)6 complexes of broad substrate specificity that can resist and downregulate cellular CDK inhibitors. This study shows that the viral cyclin of H. saimiri strain C488 is not required for viral replication, T cell transformation, and pathogenicity in New World primates.

  3. High prevalence of antibodies to human herpesvirus 8 in relatives of patients with classic Kaposi's sarcoma from Sardinia.

    PubMed

    Angeloni, A; Heston, L; Uccini, S; Sirianni, M C; Cottoni, F; Masala, M V; Cerimele, D; Lin, S F; Sun, R; Rigsby, M; Faggioni, A; Miller, G

    1998-06-01

    A survey for antibodies to a recombinant small viral capsid antigen (sVCA) of human herpesvirus type 8 (HHV-8) was conducted in Sardinia, one of the world's highest incidence areas for classic Kaposi's sarcoma (KS). Prevalence of antibodies to HHV-8 sVCA was greatest in patients with KS (95%), followed by family members (39%) and a Sardinian control population age- and sex-matched to the relatives (11%). Within families, prevalence of antibodies was about equal among spouses, children, and siblings of KS patients, a finding that raises the possibilities of intrafamilial person-to-person or vertical transmission. Antibodies were detected 2-3 times more frequently in males than in females. The data show that prevalence of antibodies to HHV-8 sVCA correlates with the distribution of classic KS in a high- incidence area. Clustering of seroprevalence within some families suggests the presence of familial risk factors for active HHV-8 infection.

  4. Effect of electrochemotherapy on human herpesvirus 8 kinetics in classic Kaposi sarcoma.

    PubMed

    Starita, Noemy; Di Monta, Gianluca; Cerasuolo, Andrea; Marone, Ugo; Anniciello, Anna Maria; Botti, Gerardo; Buonaguro, Luigi; Buonaguro, Franco M; Tornesello, Maria Lina

    2017-01-01

    Electrochemotherapy (ECT) has shown to be an effective treatment for cutaneous and subcutaneous Kaposi sarcoma (KS) lesions. However, no study has investigated the impact of ECT treatment on the kinetics of human herpesvirus type 8 (HHV8), which is considered the necessary causal agent of KS. We aimed to evaluate HHV8 viral load and expression levels in patients affected by classic KS who received one or more ECT treatments and have been followed semi annually for up to four years. A total of 27 classic KS patients were enrolled in this study. Tumour biopsies and blood samples were obtained before ECT treatment. Additional blood samples were collected at six month intervals for 12-48 months. HHV8 viral load and expression profiles of latent (ORF72 and ORF73) and lytic (K2, K8, K8.1, K10/K10.1, K10.5/K10.6 and ORF16) genes were assessed in all samples by real-time PCR. HHV8 ORF26 and K1 regions were amplified and subjected to direct nucleotide sequencing followed by phylogenetic analysis for variant identification. All KS biopsies and 46.4% of peripheral blood mononuclear cells (PBMCs) collected before ECT treatment were positive for HHV8 DNA. Viral load ranged from 0.02 to 2.3 copies per cell in KS lesions and 3.0 × 10(-7) to 6.9 × 10(-4) copies per cell in PBMCs. Overall, latent ORF72 and ORF73 as well as lytic K2, K8 and K10/K10.1 were expressed in all KS biopsies. ORF16 mRNA was detected in 71.4% and both K8.1 and K10.5/K10.6 mRNAs in 57.1% of KS samples. The ORF72, ORF73 and K2 transcripts were amplified in 37.5%, 25% and 25% of PBMCs collected before ECT, respectively. After the first ECT session, complete response was achieved in 20 out of 27 (74.1%) patients and HHV8 DNA was detected in four out of 27 (14.8%) PBMC samples at six month follow up. Phylogenetic analysis of ORF26 amplimers showed that most viral variants belonged to A/C (82.3%), and few to C2 (5.9%) or C3 (11.8%) subtype. The K1/VR1 variants fell into A (33.3%) and C (66.7%) HHV8 clade

  5. Fine-Tuning of the Kaposi’s Sarcoma-Associated Herpesvirus Life Cycle in Neighboring Cells through the RTA-JAG1-Notch Pathway

    PubMed Central

    He, Zhiheng; Liang, Deguang; Sun, Rui; Lan, Ke

    2016-01-01

    Kaposi’s sarcoma (KS)-associated herpesvirus (KSHV) is an oncogenic pathogen that displays latent and lytic life cycles. In KS lesions, infiltrated immune cells, secreted viral and/or cellular cytokines, and hypoxia orchestrate a chronic pro-lytic microenvironment that can promote KSHV reactivation. However, only a small subset of viruses spontaneously undergoes lytic replication in this pro-lytic microenvironment while the majority remains in latency. Here, we show that the expression of the Notch ligand JAG1 is induced by KSHV-encoded replication and transcription activator (RTA) during reactivation. JAG1 up-regulation activates Notch signaling in neighboring cells and prevents viral lytic replication. The suppression of JAG1 and Notch1 with inhibitors or small interfering RNA promotes lytic replication in the presence of RTA induction or under conditions of hypoxia. The underlying mechanism involves the Notch downstream effector hairy and enhancer of split 1 (Hes1), which directly binds lytic gene promoters and attenuates viral lytic gene expression. RTA interacts with lymphoid enhancer-binding factor 1 (LEF1), disrupts LEF1/Groucho/TLE suppressive complexes and releases LEF1 to activate JAG1 expression. Taken together, our results suggest that cells with viral lytic replication can inhibit KSHV reactivation in neighboring cells through an RTA-JAG1-Notch pathway. These data provide insight into the mechanism by which the virus maintains the balance between lytic and latent infection in the pro-lytic tumor microenvironment. PMID:27760204

  6. Herpesvirus saimiri.

    PubMed

    Fickenscher, H; Fleckenstein, B

    2001-04-29

    Herpesvirus saimiri (saimiriine herpesvirus 2) is the classical prototype of the gamma(2)-herpesviruses or rhadinoviruses, which also contains a human member, the Kaposi's sarcoma-associated herpesvirus. The T-lymphotropic Herpesvirus saimiri establishes specific replicative and persistent conditions in different primate host species. Virtually all squirrel monkeys (Saimiri sciureus) are persistently infected with this virus. In its natural host, the virus does not cause disease, whereas it induces fatal acute T-cell lymphoma in other monkey species after experimental infection. The virus can be isolated by cocultivation of permissive epithelial cells with peripheral blood cells from naturally infected squirrel monkeys and from susceptible New World monkeys during the virus-induced disease. Tumour-derived and in vitro-transformed T-cell lines from New World monkeys release virus particles. Herpesvirus ateles is a closely related virus of spider monkeys (Ateles spp.) and has similar pathogenic properties to Herpesvirus saimiri in other New World primate species. Similar to other rhadinoviruses, the genome of Herpesvirus saimiri harbours a series of virus genes with pronounced homology to cellular counterparts including a D-type cyclin, a G-protein-coupled receptor, an interleukin-17, a superantigen homologue, and several inhibitors of the complement cascade and of different apoptosis pathways. Preserved function has been demonstrated for most of the homologues of cellular proteins. These viral functions are mostly dispensable for the transforming and pathogenic capability of the virus. However, they are considered relevant for the apathogenic persistence of Herpesvirus saimiri in its natural host. A terminal region of the non-repetitive coding part of the virus genome is essential for pathogenicity and T-cell transformation. Based on the pathogenic phenotypes and the different alleles of this variable region, the virus strains have been assigned to three subgroups

  7. Herpesvirus saimiri.

    PubMed Central

    Fickenscher, H; Fleckenstein, B

    2001-01-01

    Herpesvirus saimiri (saimiriine herpesvirus 2) is the classical prototype of the gamma(2)-herpesviruses or rhadinoviruses, which also contains a human member, the Kaposi's sarcoma-associated herpesvirus. The T-lymphotropic Herpesvirus saimiri establishes specific replicative and persistent conditions in different primate host species. Virtually all squirrel monkeys (Saimiri sciureus) are persistently infected with this virus. In its natural host, the virus does not cause disease, whereas it induces fatal acute T-cell lymphoma in other monkey species after experimental infection. The virus can be isolated by cocultivation of permissive epithelial cells with peripheral blood cells from naturally infected squirrel monkeys and from susceptible New World monkeys during the virus-induced disease. Tumour-derived and in vitro-transformed T-cell lines from New World monkeys release virus particles. Herpesvirus ateles is a closely related virus of spider monkeys (Ateles spp.) and has similar pathogenic properties to Herpesvirus saimiri in other New World primate species. Similar to other rhadinoviruses, the genome of Herpesvirus saimiri harbours a series of virus genes with pronounced homology to cellular counterparts including a D-type cyclin, a G-protein-coupled receptor, an interleukin-17, a superantigen homologue, and several inhibitors of the complement cascade and of different apoptosis pathways. Preserved function has been demonstrated for most of the homologues of cellular proteins. These viral functions are mostly dispensable for the transforming and pathogenic capability of the virus. However, they are considered relevant for the apathogenic persistence of Herpesvirus saimiri in its natural host. A terminal region of the non-repetitive coding part of the virus genome is essential for pathogenicity and T-cell transformation. Based on the pathogenic phenotypes and the different alleles of this variable region, the virus strains have been assigned to three subgroups

  8. Requirement of UAP56, URH49, RBM15, and OTT3 in the expression of Kaposi sarcoma-associated herpesvirus ORF57

    SciTech Connect

    Majerciak, Vladimir; Deng, Merlyn; Zheng Zhiming

    2010-11-25

    Transport of mRNA from the nucleus to the cytoplasm is mediated by cellular RNA export factors. In this report, we examined how RNA export factors UAP56 and URH49, and RNA export cofactors RBM15 and OTT3, function in modulating KSHV ORF57 expression. We found that knockdown of each factor by RNAi led to decreased ORF57 expression. Specifically, reduced expression of either UAP56 or RBM15 led to nuclear export deficiency of ORF57 RNA. In the context of the KSHV genome, the near absence of UAP56 or RBM15 reduced the expression of both ORF57 and ORF59 (an RNA target of ORF57), but not ORF50. Collectively, our data indicate that the expression of KSHV ORF57 is regulated by cellular RNA export factors and cofactors at the posttranscriptional level.

  9. Regulatory T Cell Effect on CD8(+) T Cell Responses to Human Herpesvirus 8 Infection and Development of Kaposi's Sarcoma.

    PubMed

    Lepone, Lauren M; Rappocciolo, Giovanna; Piazza, Paolo A; Campbell, Diana M; Jenkins, Frank J; Rinaldo, Charles R

    2017-03-02

    We assessed CD8(+) T cell reactivity to human herpesvirus 8 (HHV-8; Kaposi's sarcoma [KS]-associated herpesvirus) and the role of CD4(+)CD25(hi)FoxP3(+) regulatory T cells (Treg) in HHV-8- and HIV-coinfected participants of the Multicenter AIDS Cohort Study who did or did not develop KS. There were similarly low CD8(+) T cell interferon-γ responses to MHC class I-restricted epitopes of HHV-8 lytic and latent proteins over 5.7 years before KS in participants who developed KS compared to those who did not. T cell reactivity to HHV-8 antigens was low relative to responses to a combination of cytomegalovirus, Epstein-Barr virus and influenza A virus (CEF) peptide epitopes, and dominant HIV peptide epitopes. There was no change in %Treg in the HHV-8- and HIV-coinfected participants who did not develop KS, whereas there was a significant increase in %Treg in HHV-8- and HIV-coinfected participants who developed KS beginning 1.8 years before development of KS. Removal of Treg enhanced HHV-8-specific T cell responses in HHV-8- and HIV-coinfected participants who did or did not develop KS, with a similar pattern observed in response to CEF and HIV peptides. Thus, long-term, low levels of anti-HHV-8 CD8(+) T cell reactivity were present in both HHV-8- and HIV-coinfected men who did and did not develop KS. This was related to moderately enhanced Treg function.

  10. Cytoplasmic isoforms of Kaposi sarcoma herpesvirus LANA recruit and antagonize the innate immune DNA sensor cGAS

    PubMed Central

    Zhang, Guigen; Chan, Baca; Samarina, Naira; Abere, Bizunesh; Weidner-Glunde, Magdalena; Buch, Anna; Pich, Andreas; Brinkmann, Melanie M.; Schulz, Thomas F.

    2016-01-01

    The latency-associated nuclear antigen (LANA) of Kaposi sarcoma herpesvirus (KSHV) is mainly localized and functions in the nucleus of latently infected cells, playing a pivotal role in the replication and maintenance of latent viral episomal DNA. In addition, N-terminally truncated cytoplasmic isoforms of LANA, resulting from internal translation initiation, have been reported, but their function is unknown. Using coimmunoprecipitation and MS, we found the cGMP-AMP synthase (cGAS), an innate immune DNA sensor, to be a cellular interaction partner of cytoplasmic LANA isoforms. By directly binding to cGAS, LANA, and particularly, a cytoplasmic isoform, inhibit the cGAS-STING–dependent phosphorylation of TBK1 and IRF3 and thereby antagonize the cGAS-mediated restriction of KSHV lytic replication. We hypothesize that cytoplasmic forms of LANA, whose expression increases during lytic replication, inhibit cGAS to promote the reactivation of the KSHV from latency. This observation points to a novel function of the cytoplasmic isoforms of LANA during lytic replication and extends the function of LANA from its role during latency to the lytic replication cycle. PMID:26811480

  11. Cross-species conservation of episome maintenance provides a basis for in vivo investigation of Kaposi's sarcoma herpesvirus LANA.

    PubMed

    Habison, Aline C; de Miranda, Marta Pires; Beauchemin, Chantal; Tan, Min; Cerqueira, Sofia A; Correia, Bruno; Ponnusamy, Rajesh; Usherwood, Edward J; McVey, Colin E; Simas, J Pedro; Kaye, Kenneth M

    2017-09-01

    Many pathogens, including Kaposi's sarcoma herpesvirus (KSHV), lack tractable small animal models. KSHV persists as a multi-copy, nuclear episome in latently infected cells. KSHV latency-associated nuclear antigen (kLANA) binds viral terminal repeat (kTR) DNA to mediate episome persistence. Model pathogen murine gammaherpesvirus 68 (MHV68) mLANA acts analogously on mTR DNA. kLANA and mLANA differ substantially in size and kTR and mTR show little sequence conservation. Here, we find kLANA and mLANA act reciprocally to mediate episome persistence of TR DNA. Further, kLANA rescued mLANA deficient MHV68, enabling a chimeric virus to establish latent infection in vivo in germinal center B cells. The level of chimeric virus in vivo latency was moderately reduced compared to WT infection, but WT or chimeric MHV68 infected cells had similar viral genome copy numbers as assessed by immunofluorescence of LANA intranuclear dots or qPCR. Thus, despite more than 60 Ma of evolutionary divergence, mLANA and kLANA act reciprocally on TR DNA, and kLANA functionally substitutes for mLANA, allowing kLANA investigation in vivo. Analogous chimeras may allow in vivo investigation of genes of other human pathogens.

  12. Immune escape of γ-herpesviruses from adaptive immunity.

    PubMed

    Hu, Zhuting; Usherwood, Edward J

    2014-11-01

    Epstein-Barr virus (EBV) and Kaposi's sarcoma-associated herpesvirus (KSHV) are two γ-herpesviruses identified in humans and are strongly associated with the development of malignancies. Murine γ-herpesvirus (MHV-68) is a naturally occurring rodent pathogen, representing a unique experimental model for dissecting γ-herpesvirus infection and the immune response. These γ-herpesviruses actively antagonize the innate and adaptive antiviral responses, thereby efficiently establishing latent or persistent infections and even promoting development of malignancies. In this review, we summarize immune evasion strategies of γ-herpesviruses. These include suppression of MHC-I-restricted and MHC-II-restricted antigen presentation, impairment of dendritic cell functions, downregulation of costimulatory molecules, activation of virus-specific regulatory T cells, and induction of inhibitory cytokines. There is a focus on how both γ-herpesvirus-derived and host-derived immunomodulators interfere with adaptive antiviral immunity. Understanding immune-evasive mechanisms is essential for developing future immunotherapies against EBV-driven and KSHV-driven tumors.

  13. Two Distinct Gamma-2 Herpesviruses in African Green Monkeys: a Second Gamma-2 Herpesvirus Lineage among Old World Primates?

    PubMed Central

    Greensill, Julie; Sheldon, Julie A.; Renwick, Neil M.; Beer, Brigitte E.; Norley, Steve; Goudsmit, Jaap; Schulz, Thomas F.

    2000-01-01

    Primate gamma-2 herpesviruses (rhadinoviruses) have so far been found in humans (Kaposi's sarcoma-associated herpesvirus [KSHV], also called human herpesvirus 8), macaques (Macaca spp.) (rhesus rhadinovirus [RRV] and retroperitoneal fibromatosis herpesvirus [RFHV]), squirrel monkeys (Saimiri sciureus) (herpesvirus saimiri), and spider monkeys (Ateles spp.) (herpesvirus ateles). Using serological screening and degenerate consensus primer PCR for the viral DNA polymerase gene, we have detected sequences from two distinct gamma-2 herpesviruses, termed Chlorocebus rhadinovirus 1 (ChRV1) and ChRV2, in African green monkeys. ChRV1 is more closely related to KSHV and RFHV, whereas ChRV2 is closest to RRV. Our findings suggest the existence of two distinct rhadinovirus lineages, represented by the KSHV/RFHV/ChRV1 group and the RRV/ChRV2 group, respectively, in at least two Old World monkey species. Antibodies to members of the RRV/ChRV2 lineage may cross-react in an immunofluorescence assay for early and late KSHV antigens. PMID:10627572

  14. Non-detection of human herpesvirus 8 (HHV-8) DNA in HHV-8-seropositive blood donors from three Brazilian regions.

    PubMed

    Levi, José Eduardo; Nascimento, Maria Claudia; Sumita, Laura Masami; de Souza, Vanda Akico Ueda Fick; Freire, Wilton S; Mayaud, Philippe; Pannuti, Claudio S

    2011-01-01

    Human herpesvirus 8 (HHV-8), also known as Kaposi's sarcoma-associated herpesvirus (KSHV), is the etiologic agent of all forms of Kaposi's sarcoma, primary effusion lymphoma and the plasmablastic cell variant of multicentric Castleman disease. In endemic areas of sub-Saharan Africa, blood transfusions have been associated with a substantial risk of HHV-8 transmission. By contrast, several studies among healthy blood donors from North America have failed to detect HHV-8 DNA in samples of seropositive individuals. In this study, using a real-time PCR assay, we investigated the presence of HHV-8 DNA in whole-blood samples of 803 HHV-8 blood donors from three Brazilian states (São Paulo, Amazon, Bahia) who tested positive for HHV-8 antibodies, in a previous multicenter study. HHV-8 DNA was not detected in any sample. Our findings do not support the introduction of routine HHV-8 screening among healthy blood donors in Brazil. (WC = 140).

  15. Human herpesvirus-8 infection and Kaposi's sarcoma after liver and kidney transplantation in different geographical areas of Spain.

    PubMed

    García-Astudillo, Luis Alfonso; Leyva-Cobián, Francisco

    2006-12-01

    Since data on human herpesvirus 8 (HHV-8) infection in Spain is not available, our purpose was to determine the prevalence of HHV-8 infection and the risk of developing Kaposi's sarcoma (KS) among organ transplant recipients in different geographical areas of Spain. The study population consisted of 1019 liver and kidney transplant recipients recruited in four transplant units in Spain. Only post-transplant serum samples were available for all participants. IgG anti-HHV-8 latent and lytic antigens were detected by using an indirect immunofluorescence assay as well as enzyme-linked immunosorbant assays. In available samples, HHV-8 DNA genome was detected by using a nested polymerase chain reaction in sera, blood mononuclear cells and KS tissues. The prevalence of HHV-8 infection after transplantation was calculated. To determine risk factors for infection, odds ratios (OR) and 95% confidence intervals (CI) were also calculated. Of the 788 kidney transplants, 5 (0.6%) were HHV-8-positive shortly after transplantation. Of the 231 liver transplant individuals, 8 (3.4%) developed IgG anti-HHV-8 antibodies after transplantation. Thus, incidence of HHV-8 infection is significantly higher among liver transplant recipients in comparison with that in the control population (OR=6, 95% CI=1.2-28.5, p<0.05). In this series, HHV-8 prevalence in liver transplant recipients was higher in the northern (6.6-6.9%) than in the central (2.9%) or the southeastern (1.4%) areas of Spain. Four renal transplant recipients (0.5%) and five of the liver transplant recipients (2.16%) developed KS after transplantation. Time of KS diagnosis after transplant is significantly higher in kidney transplant patients (33.7 months) than in liver transplant recipients (10.4 months), indicating that the latter have a higher risk of developing KS.

  16. The clinical application of plasma Kaposi sarcoma herpesvirus viral load as a tumour biomarker: results from 704 patients.

    PubMed

    Haq, I-U; Dalla Pria, A; Papanastasopoulos, P; Stegmann, K; Bradshaw, D; Nelson, M; Bower, M

    2016-01-01

    The aim of the study was to evaluate the role of plasma Kaposi sarcoma herpesvirus (KSHV) as a diagnostic and prognostic biomarker in people living with HIV (PLWH) and diagnosed with KSHV-associated diseases. Using quantitative nested polymerase chain reaction (PCR) targeting the open reading frame-26 gene of KSHV, plasma levels of KSHV were measured in consecutive PLWH with KSHV-associated diseases or as part of the investigation of lymphadenopathy. Plasma KSHV assays were performed on samples from 684 PLWH and 20 HIV-seronegative people with KSHV-associated malignancies. In PLWH, plasma KSHV was detected in 39% of those with KS, 99% of those with multicentric Castleman disease (MCD), 9% of those with non-Hodgkin lymphoma (NHL), 2% of those with non-AIDS-defining malignancies and 0% of those with nonmalignant lymphadenopathy. There was no significant difference in plasma KSHV viral load among those with KS, MCD and KSHV-associated NHL. The 5-year overall survival rate from KS diagnosis of 335 PLWH was 95.2% (95% confidence interval 92.6-97.8%). Plasma KSHV viraemia did not predict overall survival in those with KS (P = 0.73), nor when those with T0 stage KS (P = 0.52) or T1 stage KS (P = 0.62) were analysed separately. Measuring the plasma levels of KSHV as a biomarker in KSHV-associated disease has a very limited value in either diagnosis or prognostication. The only potential role of clinical value is the suggestion that an undetectable plasma KSHV excludes a diagnosis of MCD in PLWH. © 2015 British HIV Association.

  17. Human and viral interleukin-6 and other cytokines in Kaposi sarcoma herpesvirus-associated multicentric Castleman disease

    PubMed Central

    Uldrick, Thomas S.; Wang, Victoria; Aleman, Karen; Wyvill, Kathleen M.; Marshall, Vickie; Pittaluga, Stefania; O’Mahony, Deirdre; Whitby, Denise; Tosato, Giovanna; Steinberg, Seth M.; Little, Richard F.

    2013-01-01

    Kaposi sarcoma herpesvirus (KSHV)-associated multicentric Castleman disease (MCD) is a polyclonal B-cell lymphoproliferative disorder. Human (h) IL-6 and a KSHV-encoded homolog, viral IL-6, have been hypothesized to contribute to its pathogenesis, but their relative contributions to disease activity is not well understood. We prospectively characterized KSHV viral load (VL), viral (v) and hIL-6, and other cytokines during KSHV-MCD flare and remission in 21 patients with 34 flares and 20 remissions. KSHV-VL, vIL-6, hIL-6, IL-10, and to a lesser extent TNF-α, and IL-1β were each elevated during initial flares compared with remission. Flares fell into 3 distinct IL-6 profiles: those associated with elevations of vIL6-only (2 flares, 6%), hIL-6 elevations only (17 flares, 50%), and elevations in both hIL-6 and vIL-6 (13 flares, 38%). Compared with hIL-6–only flares, flares with elevated hIL-6 plus vIL-6 exhibited higher C-reactive protein (CRP) (P = .0009); worse hyponatremia (P = .02); higher KSHV VL (P = .016), and higher IL-10 (P = .012). This analysis shows vIL-6 and hIL-6 can independently or together lead to KSHV-MCD flares, and suggests that vIL-6 and hIL-6 may jointly contribute to disease severity. These findings have implications for the development of novel KSHV-MCD therapies targeting IL-6 and its downstream signaling. This trial was registered at clinicaltrials.gov as #NCT099073. PMID:24174627

  18. Classic Solitary Kaposi Sarcoma of the Foot in an Immunocompetent Patient: A Case Report.

    PubMed

    Schmidt, Brian M; Holmes, Crystal M

    2016-09-01

    Kaposi sarcoma (KS) is a tumor derived from endothelial cell lineage caused by Kaposi sarcoma-associated virus or human herpesvirus-8. The authors have set forth to describe a unique presentation of the classical form of KS in a homosexual individual. The authors demonstrate that a full history and physical are important in determining how to guide treatment along with ancillary tests, which can prove vital to determine management strategy. The authors then provide a brief discussion about variants of KS, biopsy techniques, and current treatment options available to patients diagnosed with this condition. The patient described is a 60-year-old male of Eastern European descent, who is immunocompetent in a monogamous homosexual relationship with a new onset and rapidly progressing skin lesion on the plantar aspect of his foot. Surgical excision of the tumor was performed and surveillance was determined to be the treatment of choice.

  19. Kaposi sarcoma.

    PubMed

    Radu, Oana; Pantanowitz, Liron

    2013-02-01

    Kaposi sarcoma (KS) is a low-grade vascular tumor associated with Kaposi sarcoma herpesvirus/human herpesvirus 8 (KSHV/HHV8) infection. Kaposi sarcoma lesions predominantly present at mucocutaneous sites, but may involve all organs and anatomic locations. Recognized epidemiologic-clinical forms of KS include classic, African (endemic), AIDS-associated (epidemic), and iatrogenic KS. New clinical manifestations have been described, such as antiretroviral therapy-related KS regression or flares. Kaposi sarcoma lesions evolve from early (patch stage) macules into plaques (plaque stage) that grow into larger nodules (tumor stage). Newer histologic variants include anaplastic, hyperkeratotic, lymphangioma-like, bullous, telangiectatic, ecchymotic, keloidal, pyogenic granuloma-like, micronodular, intravascular, glomeruloid and pigmented KS, as well as KS with sarcoidlike granulomas and KS with myoid nodules. Latency-associated nuclear antigen (HHV8) is the most specific immunohistochemical marker available to help distinguish KS from its mimics. Since KS remains one of the most common AIDS-defining malignancies, it is important that pathologists be able to recognize KS and its contemporary manifestations.

  20. Impact of HIV Infection and Kaposi Sarcoma on Human Herpesvirus-8 Mucosal Replication and Dissemination in Uganda

    PubMed Central

    Johnston, Christine; Orem, Jackson; Okuku, Fred; Kalinaki, Mary; Saracino, Misty; Katongole-Mbidde, Edward; Ronald, Allan; McAdam, Keith; Huang, Meei-Li; Drolette, Linda; Selke, Stacy; Wald, Anna; Corey, Lawrence; Casper, Corey

    2009-01-01

    Introduction Kaposi sarcoma (KS) is the leading cause of cancer in Uganda and occurs in people with and without HIV. Human herpesvirus-8 (HHV-8) replication is important both in transmission of HHV-8 and progression to KS. We characterized the sites and frequency of HHV-8 detection in Ugandans with and without HIV and KS. Methods Participants were enrolled into one of four groups on the basis of HIV and KS status (HIV negative/KS negative, HIV positive/KS negative, HIV negative/KS positive, and HIV positive/KS positive). Participants collected oral swabs daily and clinicians collected oral swabs, anogenital swabs, and plasma samples weekly over 4 weeks. HHV-8 DNA at each site was quantified by polymerase chain reaction (PCR). Results 78 participants collected a total of 2063 orals swabs and 358 plasma samples. Of these, 428 (21%) oral swabs and 96 (27%) plasma samples had detectable HHV-8 DNA. HHV-8 was detected more frequently in both the oropharynx of persons with KS (24 (57%) of 42 persons with KS vs. 8 (22%) of 36 persons without, p = 0.002) and the peripheral blood (30 (71%) of 42 persons with KS vs. 8 (22%) of 36 persons without, p<0.001). In a multivariate model, HHV-8 viremia was more frequent among men (IRR = 3.3, 95% CI = 1.7–6.2, p<0.001), persons with KS (IRR = 3.9, 95% CI = 1.7–9.0, p = 0.001) and persons with HIV infection (IRR = 1.7, 95% CI = 1.0–2.7, p = 0.03). Importantly, oral HHV-8 detection predicted the subsequent HHV-8 viremia. HHV-8 viremia was significantly more common when HHV-8 DNA was detected from the oropharynx during the week prior than when oral HHV-8 was not detected (RR = 3.3, 95% CI = 1.8–5.9 p<0.001). Genital HHV-8 detection was rare (9 (3%) of 272 swabs). Conclusions HHV-8 detection is frequent in the oropharynx and peripheral blood of Ugandans with endemic and epidemic KS. Replication at these sites is highly correlated, and viremia is increased in men and those with HIV. The

  1. A gamma-2 herpesvirus nucleocytoplasmic shuttle protein interacts with importin alpha 1 and alpha 5.

    PubMed

    Goodwin, D J; Whitehouse, A

    2001-06-08

    Herpesvirus saimiri (HVS) is the prototype gamma-2 herpesvirus. This is an increasing important subfamily of herpesviruses due to the identification of the first human gamma-2 herpesvirus, Kaposi's sarcoma-associated herpesvirus. The HVS open reading frame (ORF) 57 protein is a multifunctional trans-regulatory protein homologous to genes identified in all classes of herpesviruses. Recent analysis has demonstrated that ORF 57 has the ability to bind viral RNA and to shuttle between the nucleus and cytoplasm, and is required for efficient nuclear export of viral transcripts. Here we have investigated the nucleocytoplasmic shuttling mechanism utilized by the ORF 57 protein. The yeast two-hybrid system was employed to identify interacting cellular proteins using ORF 57 as bait. We demonstrate that ORF 57 interacts with importin alpha isoforms 1 and 5. In addition, the binding of ORF 57 to importin alpha was mediated by the importin alpha hydrophobic internal armadillo repeats. An ORF 57 amino-terminal arginine-rich sequence, which functions as a nuclear localization sequence, was also required for this interaction. Furthermore, the ORF 57 protein is responsible for the redistribution of importin alpha into the nucleoli. These results identify novel cellular interactions essential for the functioning of this important herpesvirus regulatory protein.

  2. Human herpesvirus 8 DNA load in leukocytes of human immunodeficiency virus-infected subjects: correlation with the presence of Kaposi's sarcoma and response to anticytomegalovirus therapy.

    PubMed

    Boivin, G; Gaudreau, A; Toma, E; Lalonde, R; Routy, J P; Murray, G; Handfield, J; Bergeron, M G

    1999-02-01

    Specific human herpesvirus 8 (HHV-8) DNA sequences were found in leukocytes of 12 of 29 (41.4%) AIDS subjects with Kaposi's sarcoma (KS), whereas they were found in 4 of 43 (9.3%) AIDS subjects without KS (P = 0.003), although the peak HHV-8 DNA load in PCR-positive subjects with KS (mean, 425 copies per 0.2 microgram of DNA) did not significantly differ from the one found in PCR-positive patients without KS (mean, 218 copies). The use of intravenous ganciclovir or foscarnet therapy to treat cytomegalovirus disease did not affect the HHV-8 DNA load in seven patients for whom serial samples were analyzed.

  3. Sequence Analysis of Kaposi Sarcoma–Associated Herpesvirus (KSHV) MicroRNAs in Patients with Multicentric Castleman Disease and KSHV-Associated Inflammatory Cytokine Syndrome

    PubMed Central

    Ray, Alex; Marshall, Vickie; Uldrick, Thomas; Leighty, Robert; Labo, Nazzarena; Wyvill, Kathy; Aleman, Karen; Polizzotto, Mark N.; Little, Richard F.; Yarchoan, Robert; Whitby, Denise

    2012-01-01

    Background Kaposi sarcoma–associated herpesvirus (KSHV) encodes 12 pre-microRNAs that yield 25 mature microRNAs. We previously reported phylogenetic analysis of the microRNA-coding region of KSHV from Kaposi sarcoma (KS), primary effusion lymphoma (PEL), and multicentric Castleman disease (MCD) patients. We observed a high level of conservation for most sequences but also a divergent cluster of 5 KSHV sequences, including 2 from MCD patients. Methods KSHV microRNA sequences from 23 MCD patients and 7 patients with a newly described KSHV-associated inflammatory cytokine syndrome (KICS) were examined by amplification, cloning, and sequencing of a 646-bp fragment of K12/T0.7 encoding microRNA-K12-10 and microRNA-K12-12 and a 2.8-kbp fragment containing the remaining 10 pre-microRNAs. Results Phylogenetic analysis showed a distinct variant cluster consisting exclusively of MCD and KICS patients in all trees. Pearson χ2 analysis revealed that 40 single-nucleotide polymorphisms (SNPs) at various loci were significantly associated with MCD and KICS risk. Cluster analysis of these SNPs generated several combinations of 3 SNPs as putative indicators of MCD and KICS risk. Conclusions These findings show that MCD and KICS patients frequently have unusual KSHV microRNA sequences and suggest an association between the observed sequence variation and risk of MCD and KICS. PMID:22448005

  4. CD68+ cells of monocyte/macrophage lineage in the environment of AIDS-associated and classic-sporadic Kaposi sarcoma are singly or doubly infected with human herpesviruses 7 and 6B

    PubMed Central

    Kempf, W.; Adams, V.; Wey, N.; Moos, R.; Schmid, M.; Avitabile, E.; Campadelli-Fiume, G.

    1997-01-01

    Earlier studies have shown that Kaposi sarcomas contain cells infected with human herpesvirus (HHV) 6B, and in current studies we report that both AIDS-associated and classic-sporadic Kaposi sarcoma contain HHV-7 genome sequences detectable by PCR. To determine the distribution of HHV-7-infected cells relative to those infected with HHV-6, sections from paraffin-embedded tissues were allowed to react with antibodies to HHV-7 virion tegument phosphoprotein pp85 and to HHV-6B protein p101. The antibodies are specific for HHV-7 and HHV-6B, respectively, and they retained reactivity for antigens contained in formalin-fixed, paraffin-embedded tissue samples. We report that (i) HHV-7 pp85 was present in 9 of 32 AIDS-associated Kaposi sarcomas, and in 1 of 7 classical-sporadic HIV-negative Kaposi sarcomas; (ii) HHV-7 pp85 was detected primarily in cells bearing the CD68 marker characteristic of the monocyte/macrophage lineage present in or surrounding the Kaposi sarcoma lesions; and (iii) in a number of Kaposi sarcoma specimens, tumor-associated CD68+ monocytes/macrophages expressed simultaneously antigens from both HHV-7 and HHV-6B, and therefore appeared to be doubly infected with the two viruses. CD68+ monocytes/macrophages infected with HHV-7 were readily detectable in Kaposi sarcoma, but virtually absent from other normal or pathological tissues that harbor macrophages. Because all of the available data indicate that HHV-7 infects CD4+ T lymphocytes, these results suggest that the environment of the Kaposi sarcoma (i) attracts circulating peripheral lymphocytes and monocytes, triggers the replication of latent viruses, and thereby increases the local concentration of viruses, (ii) renders CD68+ monocytes/macrophages susceptible to infection with HHV-7, and (iii) the combination of both events enables double infections of cells with both HHV-6B and HHV-7. PMID:9207138

  5. NFκB pathway is down-regulated by 1α,25(OH)(2)-vitamin D(3) in endothelial cells transformed by Kaposi sarcoma-associated herpes virus G protein coupled receptor.

    PubMed

    Gonzalez-Pardo, Verónica; D'Elia, Noelia; Verstuyf, Annemieke; Boland, Ricardo; Russo de Boland, Ana

    2012-09-01

    We have previously demonstrated that 1α,25 dihydroxy-vitamin D(3) (1α,25(OH)(2)D(3)) has antiproliferative effects on the growth of endothelial cells transformed by the viral G protein-coupled receptor associated to Kaposi sarcoma (vGPCR). In this work, we have investigated whether 1α,25(OH)(2)D(3) exerts its growth inhibitory effects by inhibiting the Nuclear Factor κ B (NFκB) pathway which is highly activated by vGPCR. Cell proliferation studies demonstrated that 1α,25(OH)(2)D(3), similarly to bortezomib, a proteosome inhibitor that suppresses the activation of NFκB, reduced the proliferation of endothelial cells transformed by vGPCR (SVEC-vGPCR). The activity of NFκB in these cells decreased by 70% upon 1α,25(OH)(2)D(3) treatment. Furthermore, time and dose response studies showed that the hormone significantly decreased NFκB and increased IκBα mRNA and protein levels in SVEC-vGPCR cells, whereas in SVEC only IκBα increased significantly. Moreover, NFκB translocation to the nucleus was inhibited and occurred by a mechanism independent of NFκB association with vitamin D(3) receptor (VDR). 1α,25(OH)(2)D(3)-induced increase in IκBα required de novo protein synthesis, and was independent of MAPK and PI3K/Akt pathways. Altogether, these results suggest that down-regulation of the NFκB pathway is part of the mechanism involved in the antiproliferative effects of 1α,25(OH)(2)D(3) on endothelial cells transformed by vGPCR. Copyright © 2012 Elsevier Inc. All rights reserved.

  6. Kaposi sarcoma: review and medical management update.

    PubMed

    Fatahzadeh, Mahnaz

    2012-01-01

    Despite recent advances in our understanding of pathogenic mechanisms involved, the true nature of Kaposi sarcoma remains an enigma. Four clinical variants have been described for the disease, differing in natural history, site of predilection, and prognosis. All forms of Kaposi sarcoma may manifest in the oral cavity and Kaposi sarcoma-associated virus appears essential to development of all clinical variants. The spectrum of therapeutic strategies is broad and selection of appropriate intervention mandates a thorough understanding of disease spread and the patient's symptomatology, as well as risks and benefits of therapy. This article provides an overview of epidemiology, subtypes, clinical course, pathogenesis, and management strategies for Kaposi sarcoma.

  7. Global mapping of herpesvirus-host protein complexes reveals a transcription strategy for late genes.

    PubMed

    Davis, Zoe H; Verschueren, Erik; Jang, Gwendolyn M; Kleffman, Kevin; Johnson, Jeffrey R; Park, Jimin; Von Dollen, John; Maher, M Cyrus; Johnson, Tasha; Newton, William; Jäger, Stefanie; Shales, Michael; Horner, Julie; Hernandez, Ryan D; Krogan, Nevan J; Glaunsinger, Britt A

    2015-01-22

    Mapping host-pathogen interactions has proven instrumental for understanding how viruses manipulate host machinery and how numerous cellular processes are regulated. DNA viruses such as herpesviruses have relatively large coding capacity and thus can target an extensive network of cellular proteins. To identify the host proteins hijacked by this pathogen, we systematically affinity tagged and purified all 89 proteins of Kaposi's sarcoma-associated herpesvirus (KSHV) from human cells. Mass spectrometry of this material identified over 500 virus-host interactions. KSHV causes AIDS-associated cancers, and its interaction network is enriched for proteins linked to cancer and overlaps with proteins that are also targeted by HIV-1. We found that the conserved KSHV protein ORF24 binds to RNA polymerase II and brings it to viral late promoters by mimicking and replacing cellular TATA-box-binding protein (TBP). This is required for herpesviral late gene expression, a complex and poorly understood phase of the viral lifecycle.

  8. Clinical Features and Outcomes of Patients With Symptomatic Kaposi Sarcoma Herpesvirus (KSHV)-associated Inflammation: Prospective Characterization of KSHV Inflammatory Cytokine Syndrome (KICS).

    PubMed

    Polizzotto, Mark N; Uldrick, Thomas S; Wyvill, Kathleen M; Aleman, Karen; Marshall, Vickie; Wang, Victoria; Whitby, Denise; Pittaluga, Stefania; Jaffe, Elaine S; Millo, Corina; Tosato, Giovanna; Little, Richard F; Steinberg, Seth M; Sereti, Irini; Yarchoan, Robert

    2016-03-15

    Kaposi sarcoma herpesvirus (KSHV) is the cause of Kaposi sarcoma (KS), primary effusion lymphoma (PEL), and a form of Castleman disease (KSHV-MCD). Recently a KSHV-associated inflammatory cytokine syndrome (KICS) distinct from KSHV-MCD was reported. We prospectively characterized the clinical, laboratory, virologic and immunologic features of KICS by evaluating symptomatic adults with KSHV using a prespecified definition. These features and overall survival were compared with controls from 2 prospectively characterized human immunodeficiency virus (HIV)-infected cohorts, including 1 with KSHV coinfection. All 10 KICS subjects were HIV infected males; 5 had HIV viral load (VL) suppressed <50 copies mL (median 72, range <50-74 375); all had KS and 2 also had PEL. All had multiple severe symptoms attributable to KICS: median number of symptoms 8 (6-11), median grade of worst symptom 3 (2-4). These included gastrointestinal disturbance (present in 9); edema (9); respiratory (6); and effusions (5). Laboratory abnormalities included anemia (all); hypoalbuminemia (all) and thrombocytopenia (6). None developed KSHV-MCD; 6 died with median survival from KICS diagnosis 13.6 months. KICS subjects compared with controls had more severe symptoms; lower hemoglobin and albumin; higher C-reactive protein; higher KSHV VL; elevated interleukin (IL)-6 and IL-10; and an increased risk of death (all P < .05). Anemia and hypoalbuminemia at presentation were independently associated with early death. KICS subjects demonstrated diverse severe symptoms, a high rate of KSHV-associated tumors, high mortality, and a distinct IL-6/IL-10 signature. KICS may be an important unrecognized cause of morbidity and mortality, including symptoms previously ascribed to HIV. Exploration of KSHV-directed therapy is warranted. Published by Oxford University Press for the Infectious Diseases Society of America 2015. This work is written by (a) US Government employee(s) and is in the public domain in the US.

  9. Clinical Features and Outcomes of Patients With Symptomatic Kaposi Sarcoma Herpesvirus (KSHV)-associated Inflammation: Prospective Characterization of KSHV Inflammatory Cytokine Syndrome (KICS)

    PubMed Central

    Polizzotto, Mark N.; Uldrick, Thomas S.; Wyvill, Kathleen M.; Aleman, Karen; Marshall, Vickie; Wang, Victoria; Whitby, Denise; Pittaluga, Stefania; Jaffe, Elaine S.; Millo, Corina; Tosato, Giovanna; Little, Richard F.; Steinberg, Seth M.; Sereti, Irini; Yarchoan, Robert

    2016-01-01

    Background. Kaposi sarcoma herpesvirus (KSHV) is the cause of Kaposi sarcoma (KS), primary effusion lymphoma (PEL), and a form of Castleman disease (KSHV-MCD). Recently a KSHV-associated inflammatory cytokine syndrome (KICS) distinct from KSHV-MCD was reported. Methods. We prospectively characterized the clinical, laboratory, virologic and immunologic features of KICS by evaluating symptomatic adults with KSHV using a prespecified definition. These features and overall survival were compared with controls from 2 prospectively characterized human immunodeficiency virus (HIV)-infected cohorts, including 1 with KSHV coinfection. Results. All 10 KICS subjects were HIV infected males; 5 had HIV viral load (VL) suppressed <50 copies mL (median 72, range <50–74 375); all had KS and 2 also had PEL. All had multiple severe symptoms attributable to KICS: median number of symptoms 8 (6–11), median grade of worst symptom 3 (2–4). These included gastrointestinal disturbance (present in 9); edema (9); respiratory (6); and effusions (5). Laboratory abnormalities included anemia (all); hypoalbuminemia (all) and thrombocytopenia (6). None developed KSHV-MCD; 6 died with median survival from KICS diagnosis 13.6 months. KICS subjects compared with controls had more severe symptoms; lower hemoglobin and albumin; higher C-reactive protein; higher KSHV VL; elevated interleukin (IL)-6 and IL-10; and an increased risk of death (all P < .05). Anemia and hypoalbuminemia at presentation were independently associated with early death. Conclusions. KICS subjects demonstrated diverse severe symptoms, a high rate of KSHV-associated tumors, high mortality, and a distinct IL-6/IL-10 signature. KICS may be an important unrecognized cause of morbidity and mortality, including symptoms previously ascribed to HIV. Exploration of KSHV-directed therapy is warranted. PMID:26658701

  10. Kaposi sarcoma

    MedlinePlus

    Kaposi's sarcoma; HIV - Kaposi; AIDS - Kaposi ... Before the HIV/AIDS epidemic, Kaposi sarcoma was seen mainly in older Italian and Jewish men, and rarely, in older women. Among this group, the tumors developed slowly. In ...

  11. Mycosis fungoides and Kaposi’s sarcoma association in an HIV-negative patient*

    PubMed Central

    Bariani, Maria Carolina Prado Fleury; Fleury Júnior, Luiz Fernando Fróes; Ribeiro, Ana Maria Quinteiro; Carneiro, Siderley de Souza; Pereira, Tiago Arantes

    2016-01-01

    The association of mycosis fungoides and kaposi’s sarcoma in HIV-negative patients is a rare phenomenon. The presence of human herpesvirus 8 (HHV-8) – associated with all forms of Kaposi’s sarcoma – has also been recently identified in mycosis fungoides lesions. However, a causal association between HHV-8 and the onset of mycosis fungoides has not been established yet. The present case reports a patient who developed Kaposi’s sarcoma lesions after a two-year UVB phototherapy to treat a mycosis fungoides. Negative immunohistochemistry staining for Kaposi’s sarcoma-associated herpesvirus in the initial mycosis fungoides lesions strengthens the absence of a link between Kaposi’s sarcoma-associated herpesvirus and mycosis fungoides. Immunosuppression caused by the lymphoma and prolonged phototherapy were probably the contribut ing factors for the onset of Kaposi’s sarcoma. PMID:28300912

  12. Attenuation of the suppressive activity of cellular splicing factor SRSF3 by Kaposi sarcoma–associated herpesvirus ORF57 protein is required for RNA splicing

    PubMed Central

    Majerciak, Vladimir; Lu, Mathew; Li, Xiaofan

    2014-01-01

    Kaposi sarcoma–associated herpesvirus (KSHV) ORF57 is a multifunctional post-transcriptional regulator essential for viral gene expression during KSHV lytic infection. ORF57 requires interactions with various cellular proteins for its function. Here, we identified serine/arginine-rich splicing factor 3 (SRSF3, formerly known as SRp20) as a cellular cofactor involved in ORF57-mediated splicing of KSHV K8β RNA. In the absence of ORF57, SRSF3 binds to a suboptimal K8β intron and inhibits K8β splicing. Knockdown of SRSF3 promotes K8β splicing, mimicking the effect of ORF57. The N-terminal half of ORF57 binds to the RNA recognition motif of SRSF3, which prevents SRSF3 from associating with the K8β intron RNA and therefore attenuates the suppressive effect of SRSF3 on K8β splicing. ORF57 also promotes splicing of heterologous non-KSHV transcripts that are negatively regulated by SRSF3, indicating that the effect of ORF57 on SRSF3 activity is independent of RNA target. SPEN proteins, previously identified as ORF57-interacting partners, suppress ORF57 splicing activity by displacing ORF57 from SRSF3–RNA complexes. In summary, we have identified modulation of SRSF3 activity as the molecular mechanism by which ORF57 promotes RNA splicing. PMID:25234929

  13. High-dose zidovudine plus valganciclovir for Kaposi sarcoma herpesvirus-associated multicentric Castleman disease: a pilot study of virus-activated cytotoxic therapy

    PubMed Central

    Uldrick, Thomas S.; Polizzotto, Mark N.; Aleman, Karen; O'Mahony, Deirdre; Wyvill, Kathleen M.; Wang, Victoria; Marshall, Vickie; Pittaluga, Stefania; Steinberg, Seth M.; Tosato, Giovanna; Whitby, Denise; Little, Richard F.

    2011-01-01

    Kaposi sarcoma herpesvirus (KSHV)–associated multicentric Castleman disease (MCD) is a lymphoproliferative disorder most commonly observed in HIV-infected patients. It is characterized by KSHV-infected plasmablasts that frequently express lytic genes. Patients manifest inflammatory symptoms attributed to overproduction of KSHV viral IL-6, human IL-6, and human IL-6. There is no standard therapy and no established response criteria. We investigated an approach targeting 2 KSHV lytic genes, ORF36 and ORF21, the protein of which, respectively, phosphorylate ganciclovir and zidovudine to toxic moieties. In a pilot study, 14 HIV-infected patients with symptomatic KSHV-MCD received high-dose zidovudine (600 mg orally every 6 hours) and the oral prodrug, valganciclovir (900 mg orally every 12 hours). Responses were evaluated using new response criteria. A total of 86% of patients attained major clinical responses and 50% attained major biochemical responses. Median progression-free survival was 6 months. With 43 months of median follow-up, overall survival was 86% at 12 months and beyond. At the time of best response, the patients showed significant improvements in C-reactive protein, albumin, platelets, human IL-6, IL-10, and KSHV viral load. The most common toxicities were hematologic. These observations provide evidence that therapy designed to target cells with lytic KSHV replication has activity in KSHV-MCD. This trial was registered at www.clinicaltrials.gov as #NCT00099073. PMID:21487108

  14. Host entry by gamma-herpesviruses--lessons from animal viruses?

    PubMed

    Gillet, Laurent; Frederico, Bruno; Stevenson, Philip G

    2015-12-01

    The oncogenicity of gamma-herpesviruses (γHVs) motivates efforts to control them and their persistence makes early events key targets for intervention. Human γHVs are often assumed to enter naive hosts orally and infect B cells directly. However, neither assumption is supported by direct evidence, and vaccination with the Epstein-Barr virus (EBV) gp350, to block virion binding to B cells, failed to reduce infection rates. Thus, there is a need to re-evaluate assumptions about γHV host entry. Given the difficulty of analysing early human infections, potentially much can be learned from animal models. Genomic comparisons argue that γHVs colonized mammals long before humans speciation, and so that human γHVs are unlikely to differ dramatically in behaviour from those of other mammals. Murid Herpesvirus-4 (MuHV-4), which like EBV and the Kaposi's Sarcoma-associated Herpesvirus (KSHV) persists in memory B cells, enters new hosts via olfactory neurons and exploits myeloid cells to spread. Integrating these data with existing knowledge of human and veterinary γHVs suggests a new model of host entry, with potentially important implications for infection control.

  15. Identification of Kaposi Sarcoma Herpesvirus (KSHV) vIRF1 Protein as a Novel Interaction Partner of Human Deubiquitinase USP7*

    PubMed Central

    Chavoshi, Sara; Egorova, Olga; Lacdao, Ira Kay; Farhadi, Sahar; Sheng, Yi; Saridakis, Vivian

    2016-01-01

    Viral interferon regulatory factor 1 (vIRF1), a Kaposi sarcoma herpesvirus protein, destabilizes p53 by inhibiting p53 acetylation and Hdm2 phosphorylation. This leads to increased ubiquitination and degradation of p53 by Hdm2, which cripples the cellular p53-mediated antiviral response. Ubiquitin-specific protease 7 (USP7) deubiquitinates p53 and Hdm2 and regulates their stability. We identified an EGPS consensus sequence in vIRF1, which is identical to that found in Epstein-Barr virus nuclear antigen 1 (EBNA1) that interacts with the N-terminal domain of USP7 (USP7-NTD). GST pulldown assays demonstrated that vIRF1 interacts with USP7-NTD via its EGPS motif. NMR heteronuclear single quantum correlation (HSQC) analysis revealed chemical perturbations after titration of USP7-NTD with vIRF1 44SPGEGPSGTG53 peptide. In contrast, these perturbations were reduced with a mutant vIRF1 peptide, 44SPGEGPAGTG53. Fluorescence polarization analysis indicated that the vIRF1 peptide interacted with USP7-NTD with a Kd of 2.0 μm. The crystal structure of the USP7-NTD·vIRF1 peptide complex revealed an identical mode of binding as that of the EBNA1 peptide to USP7-NTD. We also showed that USP7 interacts with vIRF1 in U2OS cells. Decreased levels of p53, but not Hdm2 or ataxia telangiectasia-mutated (ATM), were seen after expression of vIRF1, but not with a vIRF1 mutant protein. Our results support a new role for vIRF1 through deregulation of the deubiquitinating enzyme USP7 to inhibit p53-mediated antiviral responses. PMID:26786098

  16. Identification of Kaposi Sarcoma Herpesvirus (KSHV) vIRF1 Protein as a Novel Interaction Partner of Human Deubiquitinase USP7.

    PubMed

    Chavoshi, Sara; Egorova, Olga; Lacdao, Ira Kay; Farhadi, Sahar; Sheng, Yi; Saridakis, Vivian

    2016-03-18

    Viral interferon regulatory factor 1 (vIRF1), a Kaposi sarcoma herpesvirus protein, destabilizes p53 by inhibiting p53 acetylation and Hdm2 phosphorylation. This leads to increased ubiquitination and degradation of p53 by Hdm2, which cripples the cellular p53-mediated antiviral response. Ubiquitin-specific protease 7 (USP7) deubiquitinates p53 and Hdm2 and regulates their stability. We identified an EGPS consensus sequence in vIRF1, which is identical to that found in Epstein-Barr virus nuclear antigen 1 (EBNA1) that interacts with the N-terminal domain of USP7 (USP7-NTD). GST pulldown assays demonstrated that vIRF1 interacts with USP7-NTD via its EGPS motif. NMR heteronuclear single quantum correlation (HSQC) analysis revealed chemical perturbations after titration of USP7-NTD with vIRF1 (44)SPGEGPSGTG(53) peptide. In contrast, these perturbations were reduced with a mutant vIRF1 peptide, (44)SPGEGPAGTG(53). Fluorescence polarization analysis indicated that the vIRF1 peptide interacted with USP7-NTD with a Kd of 2.0 μm. The crystal structure of the USP7-NTD·vIRF1 peptide complex revealed an identical mode of binding as that of the EBNA1 peptide to USP7-NTD. We also showed that USP7 interacts with vIRF1 in U2OS cells. Decreased levels of p53, but not Hdm2 or ataxia telangiectasia-mutated (ATM), were seen after expression of vIRF1, but not with a vIRF1 mutant protein. Our results support a new role for vIRF1 through deregulation of the deubiquitinating enzyme USP7 to inhibit p53-mediated antiviral responses. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

  17. 18F-fluorodeoxyglucose Positron Emission Tomography in Kaposi Sarcoma Herpesvirus-Associated Multicentric Castleman Disease: Correlation With Activity, Severity, Inflammatory and Virologic Parameters.

    PubMed

    Polizzotto, Mark N; Millo, Corina; Uldrick, Thomas S; Aleman, Karen; Whatley, Millie; Wyvill, Kathleen M; O'Mahony, Deirdre; Marshall, Vickie; Whitby, Denise; Maass-Moreno, Roberto; Steinberg, Seth M; Little, Richard F; Yarchoan, Robert

    2015-10-15

    Kaposi sarcoma herpesvirus (KSHV)-associated multicentric Castleman disease (MCD) is a lymphoproliferative inflammatory disorder commonly associated with human immunodeficiency virus (HIV). Its presentation may be difficult to distinguish from HIV and its complications, including lymphoma. Novel imaging strategies could address these problems. We prospectively characterized (18)F-fluorodeoxyglucose positron emission tomography (PET) findings in 27 patients with KSHV-MCD. Patients were imaged with disease activity and at remission with scans evaluated blind to clinical status. Symptoms, C-reactive protein level, and HIV and KSHV loads were assessed in relation to imaging findings. KSHV-MCD activity was associated with hypermetabolic symmetric lymphadenopathy (median maximal standardized uptake value [SUVmax], 6.0; range, 2.0-8.0) and splenomegaly (3.4; 1.2-11.0), with increased metabolism also noted in the marrow (2.1; range, 1.0-3.5) and salivary glands (3.0; range, 2.0-6.0). The (18)F-fluorodeoxyglucose PET abnormalities improved at remission, with significant SUVmax decreases in the lymph nodes (P = .004), spleen (P = .008), marrow (P = .004), and salivary glands (P = .004). Nodal SUVmax correlated with symptom severity (P = .005), C-reactive protein level (R = 0.62; P = .004), and KSHV load (R = 0.54; P = .02) but not HIV load (P = .52). KSHV-MCD activity is associated with (18)F-FDG PET abnormalities of the lymph nodes, spleen, marrow, and salivary glands. These findings have clinical implications for the diagnosis and monitoring of KSHV-MCD and shed light on its pathobiologic mechanism. Published by Oxford University Press on behalf of the Infectious Diseases Society of America 2015. This work is written by (a) US Government employee(s) and is in the public domain in the US.

  18. Sequencing of bovine herpesvirus 4 v.test strain reveals important genome features

    PubMed Central

    2011-01-01

    Background Bovine herpesvirus 4 (BoHV-4) is a useful model for the human pathogenic gammaherpesviruses Epstein-Barr virus and Kaposi's Sarcoma-associated Herpesvirus. Although genome manipulations of this virus have been greatly facilitated by the cloning of the BoHV-4 V.test strain as a Bacterial Artificial Chromosome (BAC), the lack of a complete genome sequence for this strain limits its experimental use. Methods In this study, we have determined the complete sequence of BoHV-4 V.test strain by a pyrosequencing approach. Results The long unique coding region (LUR) consists of 108,241 bp encoding at least 79 open reading frames and is flanked by several polyrepetitive DNA units (prDNA). As previously suggested, we showed that the prDNA unit located at the left prDNA-LUR junction (prDNA-G) differs from the other prDNA units (prDNA-inner). Namely, the prDNA-G unit lacks the conserved pac-2 cleavage and packaging signal in its right terminal region. Based on the mechanisms of cleavage and packaging of herpesvirus genomes, this feature implies that only genomes bearing left and right end prDNA units are encapsulated into virions. Conclusions In this study, we have determined the complete genome sequence of the BAC-cloned BoHV-4 V.test strain and identified genome organization features that could be important in other herpesviruses. PMID:21846388

  19. Three-Dimensional Structure of the Human Herpesvirus 8 Capsid

    PubMed Central

    Wu, Lijun; Lo, Pierrette; Yu, Xuekui; Stoops, James K.; Forghani, B.; Zhou, Z. Hong

    2000-01-01

    Human herpesvirus 8 (HHV-8), or Kaposi's sarcoma-associated herpesvirus, is a gammaherpesvirus implicated in all forms of Kaposi's sarcoma and certain lymphomas. HHV-8 has been extensively characterized, both biochemically and immunologically, since its first description in 1994. However, its three-dimensional (3D) structure remained heretofore undetermined largely due to difficulties in viral purification. We have used log-phase cultures of body cavity-based lymphoma 1 cells induced with 12-O-tetradecanoylphorbol-13-acetate to obtain HHV-8 capsids for electron cryomicroscopy and computer reconstruction. The 3D structure of the HHV-8 capsids revealed a capsid shell composed of 12 pentons, 150 hexons, and 320 triplexes arranged on a T=16 icosahedral lattice. This structure is similar to those of herpes simplex virus type 1 (HSV-1) and human cytomegalovirus (HCMV), which are prototypical members of alpha- and betaherpesviruses, respectively. The inner radius of the HHV-8 capsid is identical to that of the HSV-1 capsid but is smaller than that of the HCMV capsid, which is consistent with the relative sizes of the genomes they enclose. While the HHV-8 capsid exhibits many structural similarities to the HSV-1 capsid, our reconstruction shows two major differences: its hexons lack the “horn-shaped” VP26 densities bound to the HSV-1 hexon subunits, and the HHV-8 triplexes appear smaller and less elongated than those of HSV-1. These differences are in excellent agreement with our sequence comparisons of HHV-8 and HSV-1 capsid proteins. This gammaherpesvirus capsid structure complements previous structural studies on alpha- and betaherpesviruses in providing an account of structural similarities and differences among capsids representing all human herpesvirus subfamilies. PMID:11000237

  20. Kaposi Sarcoma Herpesvirus (KSHV) Latency-Associated Nuclear Antigen (LANA) recruits components of the MRN (Mre11-Rad50-NBS1) repair complex to modulate an innate immune signaling pathway and viral latency.

    PubMed

    Mariggiò, Giuseppe; Koch, Sandra; Zhang, Guigen; Weidner-Glunde, Magdalena; Rückert, Jessica; Kati, Semra; Santag, Susann; Schulz, Thomas F

    2017-04-01

    Kaposi Sarcoma Herpesvirus (KSHV), a γ2-herpesvirus and class 1 carcinogen, is responsible for at least three human malignancies: Kaposi Sarcoma (KS), Primary Effusion Lymphoma (PEL) and Multicentric Castleman's Disease (MCD). Its major nuclear latency protein, LANA, is indispensable for the maintenance and replication of latent viral DNA in infected cells. Although LANA is mainly a nuclear protein, cytoplasmic isoforms of LANA exist and can act as antagonists of the cytoplasmic DNA sensor, cGAS. Here, we show that cytosolic LANA also recruits members of the MRN (Mre11-Rad50-NBS1) repair complex in the cytosol and thereby inhibits their recently reported role in the sensing of cytoplasmic DNA and activation of the NF-κB pathway. Inhibition of NF-κB activation by cytoplasmic LANA is accompanied by increased lytic replication in KSHV-infected cells, suggesting that MRN-dependent NF-κB activation contributes to KSHV latency. Cytoplasmic LANA may therefore support the activation of KSHV lytic replication in part by counteracting the activation of NF-κB in response to cytoplasmic DNA. This would complement the recently described role of cytoplasmic LANA in blocking an interferon response triggered by cGAS and thereby promoting lytic reactivation. Our findings highlight a second point at which cytoplasmic LANA interferes with the innate immune response, as well as the importance of the recently discovered role of cytoplasmic MRN complex members as innate sensors of cytoplasmic DNA for the control of KSHV replication.

  1. Vitamin D analogue TX 527 down-regulates the NF-κB pathway and controls the proliferation of endothelial cells transformed by Kaposi sarcoma herpesvirus

    PubMed Central

    González-Pardo, V; Verstuyf, A; Boland, R; Russo de Boland, A

    2013-01-01

    Background and Purpose The Kaposi sarcoma (KS)-associated herpesvirus GPCR (vGPCR) is a key molecule in the pathogenesis of KS, where it increases NF-κB gene expression and activates the NF-κB pathway. We investigated whether the less calcemic vitamin D analogue TX 527 inhibited the proliferation of endothelial cells transformed by vGPCR by modulation of the NF-κB pathway. Experimental Approach Endothelial cells transformed by vGPCR (SVEC-vGPCR) were treated with TX 527. Proliferation was measured by 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium, inner salt (MTS) and cell cycle by flow cytometry. mRNA and protein levels were measured by real-time quantitative reverse transcriptase-PCR (qRT-PCR) and immunoblot analysis respectively. Key Results TX 527, similar to bortezomib (0.5 nM), a proteasome inhibitor that inhibits the activation of NF-κB, reduced proliferation and induced G0/G1 cell cycle arrest in SVEC-vGPCR. TX 527 like 1α,25(OH)2D3, biological active form of vitamin D, decreased the activity of NF-κB comparable with the effect of bortezomib. Time-response studies showed that TX 527 significantly decreased NF-κB and increased IκBα mRNA and protein levels. The increase of IκBα was accompanied by a reduction in p65/NF-κB translocation to the nucleus. These responses were abolished when vitamin D receptor (VDR) expression was suppressed by stable transfection of shRNA against VDR. In parallel with NF-κB inhibition, there was a down-regulation of inflammatory genes such as IL-6, CCL2/MCP and CCL20/MIP3α. Conclusions and Implications These results suggest that the anti-proliferative effects of the vitamin D analogue TX 527 in SVEC-vGPCR occur by modulation of the NF-κB pathway and are VDR dependent. PMID:23647513

  2. Plasmacytoid dendritic cells in skin lesions of classic Kaposi's sarcoma.

    PubMed

    Karouni, Mirna; Kurban, Mazen; Abbas, Ossama

    2016-09-01

    Plasmacytoid dendritic cells (pDCs) are the most potent producers of type I interferons (IFNs), which allows them to provide anti-viral resistance and to link the innate and adaptive immunity by controlling the function of myeloid DCs, lymphocytes, and natural killer cells. pDCs are involved in the pathogenesis of several infectious [especially viral, such as Molluscum contagiosum (MC)], inflammatory/autoimmune, and neoplastic entities. Kaposi's sarcoma (KS) is a multifocal, systemic lympho-angioproliferative tumor associated with Kaposi's sarcoma-associated herpesvirus (KSHV) infection. Microscopy typically exhibits a chronic inflammatory lymphoplasmacytic infiltrate in addition to the vascular changes and spindle cell proliferation. Despite the extensive research done on the immune evasion strategies employed by KSHV, pDCs role in relation to KS has only rarely been investigated. Given this, we intend to investigate pDC occurrence and activity in the skin lesions of KS. Immunohistochemical staining for BDCA-2 (specific pDC marker) and MxA (surrogate marker for local type I IFN production) was performed on classic KS (n = 20) with the control group comprising inflamed MC (n = 20). As expected, BDCA-2+ pDCs were present in abundance with diffuse and intense MxA expression (indicative of local type I IFN production) in all inflamed MC cases (20 of 20, 100 %). Though present in all the KS cases, pDCs were significantly less abundant in KS than in inflamed MC cases, and MxA expression was patchy/weak in most KS cases. In summary, pDCs are part of the inflammatory host response in KS; however, they were generally low in number with decreased type I IFN production which is probably related to KSHV's ability to evade the immune system through the production of different viral proteins capable of suppressing IFN production as well as pDC function.

  3. Nucleotide sequence of the Kaposi sarcoma-associated herpesvirus (HHV8)

    PubMed Central

    Russo, James J.; Bohenzky, Roy A.; Chien, Ming-Cheng; Chen, Jing; Yan, Ming; Maddalena, Dawn; Parry, J. Preston; Peruzzi, Daniela; Edelman, Isidore S.; Chang, Yuan; Moore, Patrick S.

    1996-01-01

    The genome of the Kaposi sarcoma-associated herpesvirus (KSHV or HHV8) was mapped with cosmid and phage genomic libraries from the BC-1 cell line. Its nucleotide sequence was determined except for a 3-kb region at the right end of the genome that was refractory to cloning. The BC-1 KSHV genome consists of a 140.5-kb-long unique coding region flanked by multiple G+C-rich 801-bp terminal repeat sequences. A genomic duplication that apparently arose in the parental tumor is present in this cell culture-derived strain. At least 81 ORFs, including 66 with homology to herpesvirus saimiri ORFs, and 5 internal repeat regions are present in the long unique region. The virus encodes homologs to complement-binding proteins, three cytokines (two macrophage inflammatory proteins and interleukin 6), dihydrofolate reductase, bcl-2, interferon regulatory factors, interleukin 8 receptor, neural cell adhesion molecule-like adhesin, and a D-type cyclin, as well as viral structural and metabolic proteins. Terminal repeat analysis of virus DNA from a KS lesion suggests a monoclonal expansion of KSHV in the KS tumor. PMID:8962146

  4. Kaposi's sarcoma following immune suppressive therapy for Wegener's granulomatosis.

    PubMed

    Deschênes, Isabelle; Dion, Louise; Beauchesne, Claude; de Brum-Fernandes, Artur

    2003-03-01

    The association between Kaposi's sarcoma and infection with human herpesvirus 8 is now well recognized. Immunologic impairment is associated with 2 forms of Kaposi's sarcoma, epidemic [associated with human immunodeficiency virus (HIV) infection] and iatrogenic (associated with immunosuppressive treatment); both forms have become more common during the last decade. We describe an HIV negative 54-year-old man who developed Kaposi's sarcoma 2 months after the beginning of immuno-suppressive therapy for Wegener's granulomatosis (WG). With tapering of medication, complete remission of Kaposi's sarcoma was achieved in one year. To our knowledge, this is the second reported case of iatrogenic Kaposi's sarcoma in a patient with WG.

  5. A Novel γ2-Herpesvirus of the Rhadinovirus 2 Lineage in Chimpanzees

    PubMed Central

    Lacoste, Vincent; Mauclère, Philippe; Dubreuil, Guy; Lewis, John; Georges-Courbot, Marie-Claude; Gessain, Antoine

    2001-01-01

    Old World monkeys and, recently, African great apes have been shown, by serology and polymerase chain reaction (PCR), to harbor different γ2-herpesviruses closely related to Kaposi's sarcoma-associated Herpesvirus (KSHV). Although the presence of two distinct lineages of KSHV-like rhadinoviruses, RV1 and RV2, has been revealed in Old World primates (including African green monkeys, macaques, and, recently, mandrills), viruses belonging to the RV2 genogroup have not yet been identified from great apes. Indeed, the three yet known γ2-herpesviruses in chimpanzees (PanRHV1a/PtRV1, PanRHV1b) and gorillas (GorRHV1) belong to the RV1 group. To investigate the putative existence of a new RV2 Rhadinovirus in chimpanzees and gorillas we have used the degenerate consensus primer PCR strategy for the Herpesviral DNA polymerase gene on 40 wild-caught animals. This study led to the discovery, in common chimpanzees, of a novel γ2-herpesvirus belonging to the RV2 genogroup, termed Pan Rhadino-herpesvirus 2 (PanRHV2). Use of specific primers and internal oligonucleotide probes demonstrated the presence of this novel γ2-herpesvirus in three wild-caught animals. Comparison of a 1092-bp fragment of the DNA polymerase obtained from these three animals of the Pan troglodytes troglodytes subspecies, one from Gabon and the two others from Cameroon, revealed <1% of nucleotide divergence. The geographic colocalization as well as the phylogenetic “relationship” of the human and simian γ2-herpesviruses support the model according to which herpesviruses have diversified from a common ancestor in a manner mediating cospeciation of herpesviruses with their host species. By demonstrating the existence of two distinct Rhadinovirus lineages in common chimpanzees, our finding indicates the possible existence of a novel human γ2-herpesvirus belonging to the RV2 genogroup. [The Herpesviral DNA polymerase sequence data determined herein have been deposited at the GenBank database under

  6. Pomalidomide for Symptomatic Kaposi's Sarcoma in People With and Without HIV Infection: A Phase I/II Study.

    PubMed

    Polizzotto, Mark N; Uldrick, Thomas S; Wyvill, Kathleen M; Aleman, Karen; Peer, Cody J; Bevans, Margaret; Sereti, Irini; Maldarelli, Frank; Whitby, Denise; Marshall, Vickie; Goncalves, Priscila H; Khetani, Vikram; Figg, William D; Steinberg, Seth M; Zeldis, Jerome B; Yarchoan, Robert

    2016-12-01

    Purpose Kaposi's sarcoma (KS) is a multicentric tumor caused by Kaposi's sarcoma-associated herpesvirus. Unmet needs include therapies that are oral, anthracycline sparing, and deliverable in resource-limited settings. We evaluated pomalidomide, an oral immune modulatory agent, in patients with symptomatic KS. Methods The primary objectives were to assess tolerability, pharmacokinetics, and activity. Initial dosage level was 5 mg once per day for 21 days per 28-day cycle, with a de-escalated level of 3 mg if not tolerable, and aspirin 81 mg once per day thromboprophylaxis. HIV-infected patients required controlled viremia with either persistent KS despite 3 months of antiretroviral therapy (ART) or progressive KS despite 2 months of ART. Evaluations included tumor response and health-related quality of life (HRQL). Results Twenty-two patients were treated; 15 (68%) were HIV infected, 17 (77%) had advanced (T1) disease, and 19 (86%) previous KS therapy excluding ART. All were treated with 5 mg because no dose-limiting toxicities occurred. Over 156 cycles, the grade 3/4 adverse events possibly attributable to therapy were neutropenia (23 cycles, 10 patients), infection (1 cycle), and edema (1 cycle). Sixteen patients responded (73%; 95% CI, 50% to 89%): nine of 15 HIV-infected patients (60%; 95% CI, 32% to 84%) and all seven HIV-uninfected patients (100%; 95% CI, 59% to 100%). Median time to response was 4 weeks (range, 4 to 36 weeks). HRQL showed no impairment during therapy and improved satisfaction with appearance at end therapy ( P = .03). Significant increases in CD4(+) and CD8(+) cells were seen in patients with and without HIV, together with a transient increase in Kaposi's sarcoma-associated herpesvirus viral load at week 4 ( P = .05). Conclusion Pomalidomide is well tolerated and active in KS regardless of HIV status. Responses were rapid, with improved self-reported outcomes, and occurred in advanced and heavily pretreated disease. Correlative studies

  7. Oncogenic herpesvirus KSHV Hijacks BMP-Smad1-Id signaling to promote tumorigenesis.

    PubMed

    Liang, Deguang; Hu, Hao; Li, Shasha; Dong, Jiazhen; Wang, Xing; Wang, Yuhan; He, Li; He, Zhiheng; Gao, Yuan; Gao, Shou-Jiang; Lan, Ke

    2014-07-01

    Kaposi's sarcoma-associated herpesvirus (KSHV) is the etiological agent of Kaposi's sarcoma (KS), a malignancy commonly found in AIDS patients. Whether KS is a true neoplasm or hyperplasia has been a subject of intensive debate until recently when KSHV is unequivocally shown to efficiently infect, immortalize and transform rat primary mesenchymal precursor cells (MM). Moreover, KSHV-transformed MM cells (KMM) efficiently induce tumors with hallmark features of KS when inoculated into nude mice. Here, we showed Smad1 as a novel binding protein of KSHV latency-associated nuclear antigen (LANA). LANA interacted with and sustained BMP-activated p-Smad1 in the nucleus and enhanced its loading on the Id promoters. As a result, Ids were significantly up-regulated in KMM cells and abundantly expressed in human KS lesions. Strikingly, genetic and chemical inhibition of the BMP-Smad1-Id pathway blocked the oncogenic phenotype of KSHV-transformed cells in vitro and in vivo. These findings illustrate a novel mechanism by which a tumor virus hijacks and converts a developmental pathway into an indispensable oncogenic pathway for tumorigenesis. Importantly, our results demonstrate the efficacy of targeting the BMP-Smad1-Id pathway for inhibiting the growth of KSHV-induced tumors, and therefore identify the BMP pathway as a promising therapeutic target for KS.

  8. Oncogenic Herpesvirus KSHV Hijacks BMP-Smad1-Id Signaling to Promote Tumorigenesis

    PubMed Central

    Li, Shasha; Dong, Jiazhen; Wang, Xing; Wang, Yuhan; He, Li; He, Zhiheng; Gao, Yuan; Gao, Shou-Jiang; Lan, Ke

    2014-01-01

    Kaposi's sarcoma-associated herpesvirus (KSHV) is the etiological agent of Kaposi's sarcoma (KS), a malignancy commonly found in AIDS patients. Whether KS is a true neoplasm or hyperplasia has been a subject of intensive debate until recently when KSHV is unequivocally shown to efficiently infect, immortalize and transform rat primary mesenchymal precursor cells (MM). Moreover, KSHV-transformed MM cells (KMM) efficiently induce tumors with hallmark features of KS when inoculated into nude mice. Here, we showed Smad1 as a novel binding protein of KSHV latency-associated nuclear antigen (LANA). LANA interacted with and sustained BMP-activated p-Smad1 in the nucleus and enhanced its loading on the Id promoters. As a result, Ids were significantly up-regulated in KMM cells and abundantly expressed in human KS lesions. Strikingly, genetic and chemical inhibition of the BMP-Smad1-Id pathway blocked the oncogenic phenotype of KSHV-transformed cells in vitro and in vivo. These findings illustrate a novel mechanism by which a tumor virus hijacks and converts a developmental pathway into an indispensable oncogenic pathway for tumorigenesis. Importantly, our results demonstrate the efficacy of targeting the BMP-Smad1-Id pathway for inhibiting the growth of KSHV-induced tumors, and therefore identify the BMP pathway as a promising therapeutic target for KS. PMID:25010525

  9. The First Endogenous Herpesvirus, Identified in the Tarsier Genome, and Novel Sequences from Primate Rhadinoviruses and Lymphocryptoviruses

    PubMed Central

    Aswad, Amr; Katzourakis, Aris

    2014-01-01

    Herpesviridae is a diverse family of large and complex pathogens whose genomes are extremely difficult to sequence. This is particularly true for clinical samples, and if the virus, host, or both genomes are being sequenced for the first time. Although herpesviruses are known to occasionally integrate in host genomes, and can also be inherited in a Mendelian fashion, they are notably absent from the genomic fossil record comprised of endogenous viral elements (EVEs). Here, we combine paleovirological and metagenomic approaches to both explore the constituent viral diversity of mammalian genomes and search for endogenous herpesviruses. We describe the first endogenous herpesvirus from the genome of the Philippine tarsier, belonging to the Roseolovirus genus, and characterize its highly defective genome that is integrated and flanked by unambiguous host DNA. From a draft assembly of the aye-aye genome, we use bioinformatic tools to reveal over 100,000 bp of a novel rhadinovirus that is the first lemur gammaherpesvirus, closely related to Kaposi's sarcoma-associated virus. We also identify 58 genes of Pan paniscus lymphocryptovirus 1, the bonobo equivalent of human Epstein-Barr virus. For each of the viruses, we postulate gene function via comparative analysis to known viral relatives. Most notably, the evidence from gene content and phylogenetics suggests that the aye-aye sequences represent the most basal known rhadinovirus, and indicates that tumorigenic herpesviruses have been infecting primates since their emergence in the late Cretaceous. Overall, these data show that a genomic fossil record of herpesviruses exists despite their extremely large genomes, and expands the known diversity of Herpesviridae, which will aid the characterization of pathogenesis. Our analytical approach illustrates the benefit of intersecting evolutionary approaches with metagenomics, genetics and paleovirology. PMID:24945689

  10. [Historical Review of Kaposi sarcoma in pre-HAART era: evolution with different chemotherapy schedules and remission with ganciclovir use].

    PubMed

    Volkow, Patricia; Jacquemin, Benedicte; Zinser, Juan W; Pérez-Padilla, Rogelio

    2016-10-01

    Ganciclovir has shown in vitro anti-human herpesvirus-8 activity, Kaposi sarcoma agent. We analyzed all Kaposi sarcoma patients from 1985 to 1996 pre-HAART era and identified Kaposi sarcoma/AIDS patients who achieved complete remission prior to HAART use.

  11. Epidemic Kaposi Sarcoma

    MedlinePlus

    ... Kaposi sarcoma is found in patients who have acquired immunodeficiency syndrome (AIDS). Epidemic Kaposi sarcoma occurs in patients who have ... combines treatment for Kaposi sarcoma with treatment for AIDS. For the treatment of epidemic Kaposi sarcoma, combined ...

  12. What Is Kaposi Sarcoma?

    MedlinePlus

    ... Treatment? Kaposi Sarcoma About Kaposi Sarcoma What Is Kaposi Sarcoma? Cancer starts when cells in the body ... the lungs may cause trouble breathing. Types of Kaposi sarcoma The different types of KS are defined ...

  13. Can Kaposi Sarcoma Be Prevented?

    MedlinePlus

    ... Kaposi Sarcoma Causes, Risk Factors, and Prevention Can Kaposi Sarcoma Be Prevented? Kaposi sarcoma (KS) is caused ... Sarcoma? Can Kaposi Sarcoma Be Prevented? More In Kaposi Sarcoma About Kaposi Sarcoma Causes, Risk Factors, and ...

  14. Anti-CD20 Monoclonal Antibody Treatment of Human Herpesvirus 8-Associated, Body Cavity-Based Lymphoma with an Unusual Phenotype in a Human Immunodeficiency Virus-Negative Patient

    PubMed Central

    Pérez, Celeste L.; Rudoy, Silvia

    2001-01-01

    Human herpesvirus 8 (HHV-8), or Kaposi's sarcoma-associated herpesvirus, is a gammaherpesvirus first detected in Kaposi's sarcoma tumor cells and subsequently in primary effusion lymphoma (PEL) tumor cells and peripheral blood mononuclear cells from PEL patients. PEL has been recognized as an individual nosologic entity based on its distinctive features and consistent association with HHV-8 infection. PEL is an unusual form of body cavity-based B-cell lymphoma (BCBL). It occurs predominantly in human immunodeficiency virus (HIV)-positive patients but occasionally also in elderly HIV-negative patients. We describe a case of PEL, with ascites, bilateral pleural effusions, and a small axillary lymphadenopathy, in a 72-year-old HIV-negative man. PCR performed on a lymph node specimen and in liquid effusion was positive for HHV-8 and negative for Epstein-Barr virus. The immunophenotype of the neoplastic cells was B CD19+ CD20+ CD22+ with coexpression of CD10 and CD23 and with clonal kappa light chain rearrangement. The patient was treated with Rituximab, a chimeric (human-mouse) anti-CD20 monoclonal antibody. Thirteen months later, the patient continued in clinical remission. This is the first report of an HHV-8-associated BCBL in an HIV-negative patient in Argentina. PMID:11527816

  15. microRNA dependent and independent deregulation of long non-coding RNAs by an oncogenic herpesvirus.

    PubMed

    Sethuraman, Sunantha; Gay, Lauren Appleby; Jain, Vaibhav; Haecker, Irina; Renne, Rolf

    2017-07-01

    Kaposi's sarcoma (KS) is a highly prevalent cancer in AIDS patients, especially in sub-Saharan Africa. Kaposi's sarcoma-associated herpesvirus (KSHV) is the etiological agent of KS and other cancers like Primary Effusion Lymphoma (PEL). In KS and PEL, all tumors harbor latent KSHV episomes and express latency-associated viral proteins and microRNAs (miRNAs). The exact molecular mechanisms by which latent KSHV drives tumorigenesis are not completely understood. Recent developments have highlighted the importance of aberrant long non-coding RNA (lncRNA) expression in cancer. Deregulation of lncRNAs by miRNAs is a newly described phenomenon. We hypothesized that KSHV-encoded miRNAs deregulate human lncRNAs to drive tumorigenesis. We performed lncRNA expression profiling of endothelial cells infected with wt and miRNA-deleted KSHV and identified 126 lncRNAs as putative viral miRNA targets. Here we show that KSHV deregulates host lncRNAs in both a miRNA-dependent fashion by direct interaction and in a miRNA-independent fashion through latency-associated proteins. Several lncRNAs that were previously implicated in cancer, including MEG3, ANRIL and UCA1, are deregulated by KSHV. Our results also demonstrate that KSHV-mediated UCA1 deregulation contributes to increased proliferation and migration of endothelial cells.

  16. c-myc in Kaposi's sarcoma: analyses by fluorescent in situ hybridization and immunohistochemistry.

    PubMed

    Feller, K; Yang, S; Tung, N; Lee, J; Mahalingam, M

    2014-01-01

    The c-myc proto-oncogene plays a central role in the regulation of cellular transcription, differentiation, and apoptosis, and has been shown to be deregulated in many types of human cancer. Recent findings have demonstrated its amplification in select vascular neoplasms, such as secondary angiosarcomas, suggesting a role in angiogenesis as well. In vitro studies have shown that the c-Myc protein is an important regulatory molecule of spindle cell proliferation and migration in Kaposi's sarcoma (KS). In light of these findings, our primary aim was to ascertain whether c-myc, by promoting proliferation and angiogenesis, is an essential co-factor in the aetiopathogenesis of KS. We also attempted to determine a correlation between immunohistochemical expression of the c-Myc protein and c-myc gene copy amplification using fluorescent in situ hybridization (FISH). Samples analyzed included archival tissue of KS (n = 24). PCR for detection of Kaposi's sarcoma-associated herpesvirus DNA was performed on all samples of KS. For FISH analyses, a dual-labelled technique was employed and probes for the c-myc gene and chromosome 8 were used. The monoclonal anti-c-myc antibody, 9E10, was used for immunohistochemical analyses. While FISH analyses revealed no amplification of c-myc in any of the cases of KS, immunohistochemical analyses revealed positive staining for c-Myc in 13/24 cases (54%). Amplification of the c-myc gene was not witnessed in this preliminary study of 24 cases and thus cannot be correlated with the expression of the c-Myc protein. © 2012 The Authors. Journal of the European Academy of Dermatology and Venereology © 2012 European Academy of Dermatology and Venereology.

  17. Simultaneous quantification of human herpesvirus 8 DNA by real time PCR in different tissues of HIV infected cuban patients with Kaposi's sarcoma

    PubMed Central

    2010-01-01

    In Cuba, previous reports have shown an increase of epidemic KS, reaching a total of 120 cases by the end of 2007, despite the use of HAART. To evaluate and compare the role of human herpes virus 8 (HHV-8) viral loads in different compartments of AIDS-related Kaposi's sarcoma (AIDS-KS) patients real-time polymerase chain reaction (RT-PCR) was used to determine the genome copy number of HHV-8 in plasma, saliva, tissue and peripheral blood mononuclear cells (PBMC) of 49 AIDS-KS patients. Overall, 98% of AIDS-KS patients harbored detectable HHV-8. HHV-8 could be detected in 91.6% of KS tissue lesions showing the highest viral load (median log = 3.14 copies/100 ng DNA) followed by saliva and PBMC which were positive in 78%, and 69.2%; respectively. In contrast, HHV-8 was detected in only 37% of plasma samples, which also showed lower viral loads. Men who had sex with men (MSM) were more likely to have three-times higher HHV-8 genome copies in KS lesions when compared with tissues from heterosexuals individuals (OR 3; 95% CI 1.1 to 12.5). These results emphasize the systemic nature of HHV-8-infection and demonstrate the possible role of saliva in HHV-8 transmission among MSM. PMID:21429238

  18. A Herpesvirus Protein Selectively Inhibits Cellular mRNA Nuclear Export.

    PubMed

    Gong, Danyang; Kim, Yong Hoon; Xiao, Yuchen; Du, Yushen; Xie, Yafang; Lee, Kevin K; Feng, Jun; Farhat, Nisar; Zhao, Dawei; Shu, Sara; Dai, Xinghong; Chanda, Sumit K; Rana, Tariq M; Krogan, Nevan J; Sun, Ren; Wu, Ting-Ting

    2016-11-09

    Nuclear mRNA export is highly regulated to ensure accurate cellular gene expression. Viral inhibition of cellular mRNA export can enhance viral access to the cellular translation machinery and prevent anti-viral protein production but is generally thought to be nonselective. We report that ORF10 of Kaposi's sarcoma-associated herpesvirus (KSHV), a nuclear DNA virus, inhibits mRNA export in a transcript-selective manner to control cellular gene expression. Nuclear export inhibition by ORF10 requires an interaction with an RNA export factor, Rae1. Genome-wide analysis reveals a subset of cellular mRNAs whose nuclear export is blocked by ORF10 with the 3' UTRs of ORF10-targeted transcripts conferring sensitivity to export inhibition. The ORF10-Rae1 interaction is important for the virus to express viral genes and produce infectious virions. These results suggest that a nuclear DNA virus can selectively interfere with RNA export to restrict host gene expression for optimal replication.

  19. Inhibition of cGAS DNA Sensing by a Herpesvirus Virion Protein.

    PubMed

    Wu, Jian-jun; Li, Wenwei; Shao, Yaming; Avey, Denis; Fu, Bishi; Gillen, Joseph; Hand, Travis; Ma, Siming; Liu, Xia; Miley, Wendell; Konrad, Andreas; Neipel, Frank; Stürzl, Michael; Whitby, Denise; Li, Hong; Zhu, Fanxiu

    2015-09-09

    Invading viral DNA can be recognized by the host cytosolic DNA sensor, cyclic GMP-AMP (cGAMP) synthase (cGAS), resulting in production of the second messenger cGAMP, which directs the adaptor protein STING to stimulate production of type I interferons (IFNs). Although several DNA viruses are sensed by cGAS, viral strategies targeting cGAS are virtually unknown. We report here that Kaposi's sarcoma-associated herpesvirus (KSHV) ORF52, an abundant gammaherpesvirus-specific tegument protein, subverts cytosolic DNA sensing by directly inhibiting cGAS enzymatic activity through a mechanism involving both cGAS binding and DNA binding. Moreover, ORF52 homologs in other gammaherpesviruses also inhibit cGAS activity and similarly bind cGAS and DNA, suggesting conserved inhibitory mechanisms. Furthermore, KSHV infection evokes cGAS-dependent responses that can limit the infection, and an ORF52 null mutant exhibits increased cGAS signaling. Our findings reveal a mechanism through which gammaherpesviruses antagonize host cGAS DNA sensing.

  20. Molecular biology of human herpesvirus 8: novel functions and virus-host interactions implicated in viral pathogenesis and replication.

    PubMed

    Cousins, Emily; Nicholas, John

    2014-01-01

    Human herpesvirus 8 (HHV-8), also known as Kaposi's sarcoma-associated herpesvirus (KSHV), is the second identified human gammaherpesvirus. Like its relative Epstein-Barr virus, HHV-8 is linked to B-cell tumors, specifically primary effusion lymphoma and multicentric Castleman's disease, in addition to endothelial-derived KS. HHV-8 is unusual in its possession of a plethora of "accessory" genes and encoded proteins in addition to the core, conserved herpesvirus and gammaherpesvirus genes that are necessary for basic biological functions of these viruses. The HHV-8 accessory proteins specify not only activities deducible from their cellular protein homologies but also novel, unsuspected activities that have revealed new mechanisms of virus-host interaction that serve virus replication or latency and may contribute to the development and progression of virus-associated neoplasia. These proteins include viral interleukin-6 (vIL-6), viral chemokines (vCCLs), viral G protein-coupled receptor (vGPCR), viral interferon regulatory factors (vIRFs), and viral antiapoptotic proteins homologous to FLICE (FADD-like IL-1β converting enzyme)-inhibitory protein (FLIP) and survivin. Other HHV-8 proteins, such as signaling membrane receptors encoded by open reading frames K1 and K15, also interact with host mechanisms in unique ways and have been implicated in viral pathogenesis. Additionally, a set of micro-RNAs encoded by HHV-8 appear to modulate expression of multiple host proteins to provide conditions conducive to virus persistence within the host and could also contribute to HHV-8-induced neoplasia. Here, we review the molecular biology underlying these novel virus-host interactions and their potential roles in both virus biology and virus-associated disease.

  1. Cell surface heparan sulfate is a receptor for human herpesvirus 8 and interacts with envelope glycoprotein K8.1.

    PubMed

    Birkmann, A; Mahr, K; Ensser, A; Yağuboğlu, S; Titgemeyer, F; Fleckenstein, B; Neipel, F

    2001-12-01

    An immunodominant envelope glycoprotein is encoded by the human herpesvirus 8 (HHV-8) (also termed Kaposi's sarcoma-associated herpesvirus) K8.1 gene. The functional role of glycoprotein K8.1 is unknown, and recognizable sequence homology to K8.1 is not detectable in the genomes of most other closely related gammaherpesviruses, such as herpesvirus saimiri or Epstein-Barr virus. In search for a possible function for K8.1, we expressed the ectodomain of K8.1 fused to the Fc part of human immunoglobulin G1 (K8.1DeltaTMFc). K8.1DeltaTMFc specifically bound to the surface of cells expressing glycosaminoglycans but not to mutant cell lines negative for the expression of heparan sulfate proteoglycans. Binding of K8.1DeltaTMFc to mammalian cells could be blocked by heparin. Interestingly, the infection of primary human endothelial cells by HHV-8 could also be blocked by similar concentrations of heparin. The specificity and affinity of these interactions were then determined by surface plasmon resonance measurements using immobilized heparin and soluble K8.1. This revealed that K8.1 binds to heparin with an affinity comparable to that of glycoproteins B and C of herpes simplex virus, which are known to be involved in target cell recognition by binding to cell surface proteoglycans, especially heparan sulfate. We conclude that cell surface glycosaminoglycans play a crucial role in HHV-8 target cell recognition and that HHV-8 envelope protein K8.1 is at least one of the proteins involved.

  2. Kaposi's Sarcoma

    MedlinePlus

    ... blood cells. KS is caused by infection with human herpesvirus-8 (HHV-8). Most people infected with HHV-8 don't get KS. It usually happens in People with weak immune systems, due to HIV/AIDS, drugs taken after an organ transplant, or another disease Older men of Jewish ...

  3. General Information about Kaposi Sarcoma

    MedlinePlus

    ... Kaposi sarcoma is found in patients who have acquired immunodeficiency syndrome (AIDS). Epidemic Kaposi sarcoma occurs in patients who have ... combines treatment for Kaposi sarcoma with treatment for AIDS. For the treatment of epidemic Kaposi sarcoma, combined ...

  4. Immune reconstitution inflammatory syndrome associated with Kaposi sarcoma: higher incidence and mortality in Africa than in the UK.

    PubMed

    Letang, Emilio; Lewis, James J; Bower, Mark; Mosam, Anisa; Borok, Margareth; Campbell, Thomas B; Naniche, Denise; Newsom-Davis, Tom; Shaik, Fahmida; Fiorillo, Suzanne; Miro, Jose M; Schellenberg, David; Easterbrook, Philippa J

    2013-06-19

    To assess the incidence, predictors, and outcomes of Kaposi sarcoma-associated paradoxical immune reconstitution inflammatory syndrome (KS-IRIS) in antiretroviral therapy (ART)-naive HIV-infected patients with Kaposi sarcoma initiating ART in both well resourced and limited-resourced settings. Pooled analysis of three prospective cohorts of ART-naive HIV-infected patients with Kaposi sarcoma from sub-Saharan Africa (SSA) and one from the UK. KS-IRIS case definition was standardized across sites. Cox regression and Kaplan-Meier survival analysis were used to identify the incidence and predictors of KS-IRIS and Kaposi sarcoma-associated mortality. Fifty-eight of 417 (13.9%) eligible individuals experienced KS-IRIS with an incidence 2.5 times higher in the African vs. European cohorts (P=0.001). ART alone as initial Kaposi sarcoma treatment (hazard ratio 2.97, 95% confidence interval (CI) 1.02-8.69); T1 Kaposi sarcoma stage (hazard ratio 2.96, 95% CI 1.26-6.94); and plasma HIV-1 RNA more than 5 log₁₀ copies/ml (hazard ratio 2.14, 95% CI 1.25-3.67) independently predicted KS-IRIS at baseline. Detectable plasma Kaposi sarcoma-associated herpes virus (KSHV) DNA additionally predicted KS-IRIS among the 259 patients with KSHV DNA assessed (hazard ratio 2.98, 95% CI 1.23-7.19). Nineteen KS-IRIS patients died, all in SSA. Kaposi sarcoma mortality was 3.3-fold higher in Africa, and was predicted by KS-IRIS (hazard ratio 19.24, CI 7.62-48.58), lack of chemotherapy (hazard ratio 2.35, 95% CI 1.09-5.05), pre-ART CD4 cell count less than 200 cells/μl (hazard ratio 2.04, 95% CI 0.99-4.2), and detectable baseline KSHV DNA (hazard ratio 2.12, 95% CI 0.94-4.77). KS-IRIS incidence and mortality are higher in SSA than in the UK. This is largely explained by the more advanced Kaposi sarcoma disease and lower chemotherapy availability. KS-IRIS is a major contributor to Kaposi sarcoma-associated mortality in Africa. Our results support the need to increase awareness on KS

  5. Profile of Exosomal and Intracellular microRNA in Gamma-Herpesvirus-Infected Lymphoma Cell Lines

    PubMed Central

    Hoshina, Shiho; Sekizuka, Tsuyoshi; Kataoka, Michiyo; Hasegawa, Hideki; Hamada, Hiromichi; Kuroda, Makoto; Katano, Harutaka

    2016-01-01

    Exosomes are small vesicles released from cells, into which microRNAs (miRNA) are specifically sorted and accumulated. Two gamma-herpesviruses, Kaposi sarcoma-associated herpesvirus (KSHV) and Epstein—Barr virus (EBV), encode miRNAs in their genomes and express virus-encoded miRNAs in cells and exosomes. However, there is little information about the detailed distribution of virus-encoded miRNAs in cells and exosomes. In this study, we thus identified virus- and host-encoded miRNAs in exosomes released from KSHV- or EBV-infected lymphoma cell lines and compared them with intracellular miRNAs using a next-generation sequencer. Sequencing analysis demonstrated that 48% of the annotated miRNAs in the exosomes from KSHV-infected cells originated from KSHV. Human mir-10b-5p and mir-143-3p were much more highly concentrated in exosomes than in cells. Exosomes contained more nonexact mature miRNAs that did not exactly match those in miRBase than cells. Among the KSHV-encoded miRNAs, miRK12-3-5p was the most abundant exact mature miRNA in both cells and exosomes that exactly matched those in miRBase. Recently identified EXOmotifs, nucleotide motifs that control the loading of miRNAs into exosomes were frequently found within the sequences of KSHV-encoded miRNAs, and the presence of the EXOmotif CCCT or CCCG was associated with the localization of miRNA in exosomes in KSHV-infected cells. These observations suggest that specific virus-encoded miRNAs are sorted by EXOmotifs and accumulate in exosomes in virus-infected cells. PMID:27611973

  6. Kaposi sarcoma herpes virus latency associated nuclear antigen protein release the G2/M cell cycle blocks by modulating ATM/ATR mediated checkpoint pathway.

    PubMed

    Kumar, Amit; Sahu, Sushil Kumar; Mohanty, Suchitra; Chakrabarti, Sudipta; Maji, Santanu; Reddy, R Rajendra; Jha, Asutosh K; Goswami, Chandan; Kundu, Chanakya N; Rajasubramaniam, Shanmugam; Verma, Subhash C; Choudhuri, Tathagata

    2014-01-01

    The Kaposi's sarcoma-associated herpesvirus infects the human population and maintains latency stage of viral life cycle in a variety of cell types including cells of epithelial, mesenchymal and endothelial origin. The establishment of latent infection by KSHV requires the expression of an unique repertoire of genes among which latency associated nuclear antigen (LANA) plays a critical role in the replication of the viral genome. LANA regulates the transcription of a number of viral and cellular genes essential for the survival of the virus in the host cell. The present study demonstrates the disruption of the host G2/M cell cycle checkpoint regulation as an associated function of LANA. DNA profile of LANA expressing human B-cells demonstrated the ability of this nuclear antigen in relieving the drug (Nocodazole) induced G2/M checkpoint arrest. Caffeine suppressed nocodazole induced G2/M arrest indicating involvement of the ATM/ATR. Notably, we have also shown the direct interaction of LANA with Chk2, the ATM/ATR signalling effector and is responsible for the release of the G2/M cell cycle block.

  7. Activation of DNA Damage Response Induced by the Kaposi’s Sarcoma-Associated Herpes Virus

    PubMed Central

    Di Domenico, Enea Gino; Toma, Luigi; Bordignon, Valentina; Trento, Elisabetta; D’Agosto, Giovanna; Cordiali-Fei, Paola; Ensoli, Fabrizio

    2016-01-01

    The human herpes virus 8 (HHV-8), also known as Kaposi sarcoma-associated herpes virus (KSHV), can infect endothelial cells often leading to cell transformation and to the development of tumors, namely Kaposi’s sarcoma (KS), primary effusion lymphoma (PEL), and the plasmablastic variant of multicentric Castleman’s disease. KSHV is prevalent in areas such as sub-Saharan Africa and the Mediterranean region presenting distinct genotypes, which appear to be associated with differences in disease manifestation, according to geographical areas. In infected cells, KSHV persists in a latent episomal form. However, in a limited number of cells, it undergoes spontaneous lytic reactivation to ensure the production of new virions. During both the latent and the lytic cycle, KSHV is programmed to express genes which selectively modulate the DNA damage response (DDR) through the activation of the ataxia telangiectasia mutated (ATM) pathway and by phosphorylating factors associated with the DDR, including the major tumor suppressor protein p53 tumor suppressor p53. This review will focus on the interplay between the KSHV and the DDR response pathway throughout the viral lifecycle, exploring the putative molecular mechanism/s that may contribute to malignant transformation of host cells. PMID:27258263

  8. A Toolbox for Herpesvirus miRNA Research: Construction of a Complete Set of KSHV miRNA Deletion Mutants.

    PubMed

    Jain, Vaibhav; Plaisance-Bonstaff, Karlie; Sangani, Rajnikumar; Lanier, Curtis; Dolce, Alexander; Hu, Jianhong; Brulois, Kevin; Haecker, Irina; Turner, Peter; Renne, Rolf; Krueger, Brian

    2016-02-19

    Kaposi's sarcoma-associated herpesvirus (KSHV) encodes 12 viral microRNAs (miRNAs) that are expressed during latency. Research into KSHV miRNA function has suffered from a lack of genetic systems to study viral miRNA mutations in the context of the viral genome. We used the Escherichia coli Red recombination system together with a new bacmid background, BAC16, to create mutants for all known KSHV miRNAs. The specific miRNA deletions or mutations and the integrity of the bacmids have been strictly quality controlled using PCR, restriction digestion, and sequencing. In addition, stable viral producer cell lines based on iSLK cells have been created for wildtype KSHV, for 12 individual miRNA knock-out mutants (ΔmiR-K12-1 through -12), and for mutants deleted for 10 of 12 (ΔmiR-cluster) or all 12 miRNAs (ΔmiR-all). NGS, in combination with SureSelect technology, was employed to sequence the entire latent genome within all producer cell lines. qPCR assays were used to verify the expression of the remaining viral miRNAs in a subset of mutants. Induction of the lytic cycle leads to efficient production of progeny viruses that have been used to infect endothelial cells. Wt BAC16 and miR mutant iSLK producer cell lines are now available to the research community.

  9. Do We Know What Causes Kaposi Sarcoma?

    MedlinePlus

    ... Factors, and Prevention Do We Know What Causes Kaposi Sarcoma? Kaposi sarcoma (KS) is caused by infection ... Sarcoma? Can Kaposi Sarcoma Be Prevented? More In Kaposi Sarcoma About Kaposi Sarcoma Causes, Risk Factors, and ...

  10. KSHV and the pathogenesis of Kaposi sarcoma: listening to human biology and medicine

    PubMed Central

    Ganem, Don

    2010-01-01

    The linkage of Kaposi sarcoma (KS) to infection by a novel human herpesvirus (Kaposi sarcoma–associated herpesvirus [KSHV]) is one of the great successes of contemporary biomedical research and was achieved by using advanced genomic technologies in a manner informed by a nuanced understanding of epidemiology and clinical investigation. Ongoing efforts to understand the molecular mechanisms by which KSHV infection predisposes to KS continue to be powerfully influenced by insights emanating from the clinic. Here, recent developments in KS pathogenesis are reviewed, with particular emphasis on clinical, pathologic, and molecular observations that highlight the many differences between this process and tumorigenesis by other oncogenic viruses. PMID:20364091

  11. An Interaction between KSHV ORF57 and UIF Provides mRNA-Adaptor Redundancy in Herpesvirus Intronless mRNA Export

    PubMed Central

    Jackson, Brian R.; Boyne, James R.; Noerenberg, Marko; Taylor, Adam; Hautbergue, Guillaume M.; Walsh, Matthew J.; Wheat, Rachel; Blackbourn, David J.; Wilson, Stuart A.; Whitehouse, Adrian

    2011-01-01

    The hTREX complex mediates cellular bulk mRNA nuclear export by recruiting the nuclear export factor, TAP, via a direct interaction with the export adaptor, Aly. Intriguingly however, depletion of Aly only leads to a modest reduction in cellular mRNA nuclear export, suggesting the existence of additional mRNA nuclear export adaptor proteins. In order to efficiently export Kaposi's sarcoma-associated herpesvirus (KSHV) intronless mRNAs from the nucleus, the KSHV ORF57 protein recruits hTREX onto viral intronless mRNAs allowing access to the TAP-mediated export pathway. Similarly however, depletion of Aly only leads to a modest reduction in the nuclear export of KSHV intronless mRNAs. Herein, we identify a novel interaction between ORF57 and the cellular protein, UIF. We provide the first evidence that the ORF57-UIF interaction enables the recruitment of hTREX and TAP to KSHV intronless mRNAs in Aly-depleted cells. Strikingly, depletion of both Aly and UIF inhibits the formation of an ORF57-mediated nuclear export competent ribonucleoprotein particle and consequently prevents ORF57-mediated mRNA nuclear export and KSHV protein production. Importantly, these findings highlight that redundancy exists in the eukaryotic system for certain hTREX components involved in the mRNA nuclear export of intronless KSHV mRNAs. PMID:21814512

  12. Pulmonary Kaposi sarcoma in patients with AIDS: Scintigraphic diagnosis with sequential thallium and gallium scanning

    SciTech Connect

    Lee, V.W.; Fuller, J.D.; O'Brien, M.J.; Parker, D.R.; Cooley, T.P.; Liebman, H.A. )

    1991-08-01

    Pulmonary Kaposi sarcoma associated with acquired immunodeficiency syndrome (AIDS) is difficult to diagnose because the clinical presentations and radiographic findings are nonspecific. The authors report three proved cases of AIDS-associated pulmonary Kaposi sarcoma diagnosed with sequential thallium and gallium scans. These scans demonstrated abnormal increase of pulmonary thallium uptake, whereas the gallium uptake was negative. In the authors' experience and in reports in the radiology literature, infected areas of the chest are generally thallium-negative on the delayed (3-hour) scans but are gallium-avid, whereas lymphomas are both thallium- and gallium-avid. The authors conclude that sequential thallium and gallium scans can be used to help diagnose pulmonary Kaposi sarcoma and distinguish it from other common AIDS-associated chest complications such as lymphoma and infections.

  13. Bronchopulmonary Kaposi's sarcoma.

    PubMed

    Bashar, Nada; Innes, Nicholas; Orrell, Julian

    2015-01-01

    Kaposi's sarcoma (KS) is a highly vascular tumour, which was first described by the Hungarian dermatologist Moritz Kaposi Kohn before the discovery of the human immunodeficiency virus (HIV). Historically, KS has been linked to immunosuppression or to elderly male patients, especially in relation to diffuse cutaneous KS. We describe a case of Bronchopulmonary Kaposi's sarcoma in a patient with AIDS who was successfully treated with HAART and Liposomal Doxorubicin chemotherapy.

  14. Bronchopulmonary Kaposi's sarcoma

    PubMed Central

    Bashar, Nada; Innes, Nicholas; Orrell, Julian

    2015-01-01

    Kaposi's sarcoma (KS) is a highly vascular tumour, which was first described by the Hungarian dermatologist Moritz Kaposi Kohn before the discovery of the human immunodeficiency virus (HIV). Historically, KS has been linked to immunosuppression or to elderly male patients, especially in relation to diffuse cutaneous KS. We describe a case of Bronchopulmonary Kaposi's sarcoma in a patient with AIDS who was successfully treated with HAART and Liposomal Doxorubicin chemotherapy. PMID:26236600

  15. [Moritz Kaposi and his sarcoma].

    PubMed

    van Kessel, Anne; Quint, Koen D

    2011-01-01

    Nowadays, Kaposi sarcoma is a multidisciplinary condition, not only observed by dermatologists. Since the HIV epidemic in the 80s and 90s of the last century, more insight into the aetiology of Kaposi sarcoma has been acquired. However, this sarcoma had already been described in 1872 by a Hungarian dermatologist named Moritz Kaposi (1832-1902). Kaposi described the entity as 'idiopathic multiple pigmented sarcoma of the skin'. This entity was an extraordinary diagnosis at that time, mostly observed in Jewish or Mediterranean men. In 1912, 10 years after the death of Moritz Kaposi, the entity name was changed to Kaposi sarcoma.

  16. Kaposi sarcoma following postmastectomy lymphedema.

    PubMed

    Montero Pérez, Iria; Rodríguez-Pazos, Laura; Álvarez-Pérez, Adriana; Ferreirós, M Mercedes Pereiro; Aliste, Carlos; Suarez-Peñaranda, Jose Manuel; Toribio, Jaime

    2015-11-01

    Classical Kaposi sarcoma (KS) usually appears on lower extremities accompanied or preceded by local lymphedema. However, the development in areas of chronic lymphedema of the arms following mastectomy, mimicking a Stewart-Treves syndrome, has rarely been described. We report an 81-year-old woman who developed multiple, erythematous to purple tumors, located on areas of post mastectomy lymphedema. Histopathological examination evidenced several dermal nodules formed by spindle-shaped cells that delimitated slit-like vascular spaces with some red cell extravasation. Immunohistochemically, the human herpesvirus type 8 (HHV-8) latent nuclear antigen-1 was detected in the nuclei of most tumoral cells confirming the diagnosis of KS. Lymphedema could promote the development of certain tumors by altering immunocompetence. Although angiosarcoma (AS) is the most frequent neoplasia arising in the setting of chronic lymphedema, other tumors such as benign lymphangiomatous papules (BLAP) or KS can also develop in lymphedematous limbs. It is important to establish the difference between AS and KS because their prognosis and treatment are very different. Identification by immunohistochemistry of HHV-8 is useful for the distinction between KS and AS or BLAP.

  17. Dissecting host-virus interaction in lytic replication of a model herpesvirus.

    PubMed

    Dong, Xiaonan; Feng, Pinghui

    2011-10-07

    In response to viral infection, a host develops various defensive responses, such as activating innate immune signaling pathways that lead to antiviral cytokine production. In order to colonize the host, viruses are obligate to evade host antiviral responses and manipulate signaling pathways. Unraveling the host-virus interaction will shed light on the development of novel therapeutic strategies against viral infection. Murine γHV68 is closely related to human oncogenic Kaposi's sarcoma-associated herpesvirus and Epsten-Barr virus. γHV68 infection in laboratory mice provides a tractable small animal model to examine the entire course of host responses and viral infection in vivo, which are not available for human herpesviruses. In this protocol, we present a panel of methods for phenotypic characterization and molecular dissection of host signaling components in γHV68 lytic replication both in vivo and ex vivo. The availability of genetically modified mouse strains permits the interrogation of the roles of host signaling pathways during γHV68 acute infection in vivo. Additionally, mouse embryonic fibroblasts (MEFs) isolated from these deficient mouse strains can be used to further dissect roles of these molecules during γHV68 lytic replication ex vivo. Using virological and molecular biology assays, we can pinpoint the molecular mechanism of host-virus interactions and identify host and viral genes essential for viral lytic replication. Finally, a bacterial artificial chromosome (BAC) system facilitates the introduction of mutations into the viral factor(s) that specifically interrupt the host-virus interaction. Recombinant γHV68 carrying these mutations can be used to recapitulate the phenotypes of γHV68 lytic replication in MEFs deficient in key host signaling components. This protocol offers an excellent strategy to interrogate host-pathogen interaction at multiple levels of intervention in vivo and ex vivo. Recently, we have discovered that γHV68 usurps

  18. Disseminated Kaposi sarcoma with osseous metastases in an HIV-positive patient.

    PubMed

    Bell, Bruce M; Syed, Almas; Carmack, Susanne W; Thomas, Cody A; Layton, Kennith F

    2016-01-01

    Kaposi sarcoma is a neoplasm commonly associated with human herpesvirus 8 and HIV/AIDS. We present a 44-year-old African immigrant woman who presented to the emergency department after several months of abdominal pain. She was found to be HIV positive, and computed tomography demonstrated numerous lesions of the lungs, liver, and spleen, gastric wall thickening, and several lytic lesions of the spine. Fluoroscopy-guided biopsy of a lytic lesion of the spine yielded the diagnosis of Kaposi sarcoma. AIDS-related Kaposi sarcoma with osseous involvement is rare, with approximately 30 cases reported in the literature. When osteolytic lesions are encountered in an HIV-positive patient, Kaposi sarcoma should remain in the differential.

  19. Disseminated Kaposi sarcoma with osseous metastases in an HIV-positive patient

    PubMed Central

    Syed, Almas; Carmack, Susanne W.; Thomas, Cody A.; Layton, Kennith F.

    2016-01-01

    Kaposi sarcoma is a neoplasm commonly associated with human herpesvirus 8 and HIV/AIDS. We present a 44-year-old African immigrant woman who presented to the emergency department after several months of abdominal pain. She was found to be HIV positive, and computed tomography demonstrated numerous lesions of the lungs, liver, and spleen, gastric wall thickening, and several lytic lesions of the spine. Fluoroscopy-guided biopsy of a lytic lesion of the spine yielded the diagnosis of Kaposi sarcoma. AIDS-related Kaposi sarcoma with osseous involvement is rare, with approximately 30 cases reported in the literature. When osteolytic lesions are encountered in an HIV-positive patient, Kaposi sarcoma should remain in the differential. PMID:26722170

  20. Incidence and management of Kaposi sarcoma in renal transplant recipients: the Greek experience.

    PubMed

    Zavos, G; Moris, D; Vernadakis, S; Bokos, J; Lionaki, S; Mamarelis, G; Panagiotellis, K; Zavvos, V; Boletis, I

    2014-11-01

    One of the most common malignancies in kidney transplant recipients is Kaposi sarcoma. The incidence of Kaposi sarcoma, which develops after renal transplantation, is 400-500 times higher than that in the general population. The aims of this study were to review the experience with Kaposi sarcoma in the highest-volume transplantation Unit in Greece and to analyze clinical characteristics and response to treatment, with respect to both the patients' survival and the renal graft function. The records of 2008 renal graft recipients between March 1983 and December 2012 were retrospectively reviewed. Kaposi sarcoma was diagnosed based on clinical, laboratory, radiological, endoscopic, and histopathologic examinations. The disease was staged according to the classification of Al-Khader et al. The prevalence of Kaposi sarcoma was 1.2% in our renal transplant population. Of these, 1006 recipients underwent living-donor renal transplantation, whereas 1002 received their graft from deceased donors. Post-transplantation malignancy developed in 153 patients, among which, Kaposi sarcoma has been found in 24 cases. Of the 24 cases of Kaposi sarcoma, lesions were mainly cutaneous in 14 cases, visceral and cutaneous in 8, and concomitant visceral and lymph node involvement was observed in 2 patients. With regard to the final outcome, 20 patients (83.3%) showed remission of the disease, whereas 4 patients with visceral involvement (16.6%) did not respond to chemotherapy and discontinuation of immunosuppression and died. Moreover, 8 deaths occurred due to apparently unrelated causes. Kaposi sarcoma is an important part (15.7%) of all post-transplantation neoplasias in our series. Furthermore, our findings confirmed the previously described close association between human herpesvirus-8 and post-transplantation Kaposi sarcoma. Reduction of immunosuppression or discontinuation of calcineurin inhibitors results in remission of the disease in most of the cases. Prognosis in patients with

  1. Disseminated cutaneous Kaposi sarcoma in a patient receiving triptolide/tripdiolide for rheumatoid arthritis.

    PubMed

    Grzegorzewska, Alicja E; Frankiewicz, Dorota; Bręborowicz, Danuta; Matławska, Irena; Bylka, Wiesława

    2012-08-01

    To date, Kaposi sarcoma has not been mentioned among the adverse effects of triptolide/tripdiolide, ethyl acetate extracts or polyglycosides of the Chinese herbal remedy Tripterygium wilfordii Hook F. A patient was diagnosed with rheumatoid arthritis at the age of 29 years. She underwent treatment with corticosteroids, methotrexate and gold sodium thiosulfate, and was chronically taking ketoprofen. At the age of 59 years she started to take a powder (≈2 g/day) from a Chinese physician for treatment of rheumatoid arthritis. This powder was supplied to her regularly for 10 years. At the age of 69 years, multiple soft, violaceous to dark-red patches, plaques, nodules and blisters of varying sizes appeared on a background of severely edematous skin on her legs, and later on her arms. Biopsy specimens of the leg lesions were diagnostic for human herpesvirus 8-associated Kaposi sarcoma. Triptolide (235 µg/1 g) and tripdiolide were found in the Chinese powder by the use of Liquid Chromatography Electrospray Ionization Mass Spectrometry. Administration of the powder was stopped and medication with paclitaxel was introduced. General condition of the patient improved and skin lesions diminished significantly. This case indicates a possible association between triptolide/tripdiolide chronic intake and development of human herpesvirus 8-associated Kaposi sarcoma. Triptolide/tripdiolide could contribute to development of Kaposi sarcoma by reactivation of latent human herpesvirus 8, permitted by immunosuppression induced by triptolide.

  2. Co-Existence of Multicentric Castleman's Disease and Kaposi's Sarcoma

    PubMed Central

    Yaghoobi, Reza; Pazyar, Nader; Tavakoli, Sadigheh

    2015-01-01

    Castleman's disease (CD) or giant lymph node hyperplasia is a rare disorder that can be unicentric or multicentric. Multicentric Castleman's disease (MCD) is manifested by generalized lymphadenopathy, hepatosplenomegaly, polyclonal hypergammaglobulinemia, hematological abnormality, and constitutional symptoms. Human herpesvirus 8 (HHV-8) infection is present in nearly 100% MCD associated with HIV-1 infection, but in about 50% of cases of HIV negative. Herein, we report a 77-year-old man with systemic involvement and skin lesions on the anterior aspect of both legs in the previous site of saphenous vein angioplasty. Co-existence of MCD with Kaposi's sarcoma (KS) led us to present this rare case. PMID:26120185

  3. Human herpesvirus 8-associated neoplasms: the roles of viral replication and antiviral treatment.

    PubMed

    Gantt, Soren; Casper, Corey

    2011-08-01

    In this review, we highlight the importance of human herpesvirus 8 (HHV-8) lytic replication and the potential for antiviral therapies to prevent or treat HHV-8-related neoplasms. Diseases caused by HHV-8 infection include Kaposi sarcoma, multicentric Castleman disease (MCD), and primary effusion lymphoma (PEL), which occur primarily in patients with HIV infection. Kaposi sarcoma is the most common AIDS-associated malignancy worldwide. MCD and PEL occur less commonly but, like Kaposi sarcoma, are associated with poor treatment outcomes. Like all herpesviruses, HHV-8 is capable of either latent or lytic infection of cells. Although HHV-8 infection of tumor cells is predominately latent, accumulating data point to the importance of both lytic phase viral gene products and production of infectious virus. Antiviral agents that target herpesvirus DNA synthesis, such as ganciclovir, inhibit HHV-8 lytic replication and can prevent Kaposi sarcoma. Several HIV protease inhibitors may interfere with tumor growth and angiogenesis, and one protease inhibitor, nelfinavir, directly inhibits HHV-8 replication in vitro. Controlled trials are indicated to determine the clinical utility of antiviral suppression of HHV-8 replication, and identify the optimal antiretroviral regimens, for the prevention and treatment of Kaposi sarcoma.

  4. Utilising proteomic approaches to understand oncogenic human herpesviruses (Review)

    PubMed Central

    OWEN, CHRISTOPHER B.; HUGHES, DAVID J.; BAQUERO-PEREZ, BELINDA; BERNDT, ANJA; SCHUMANN, SOPHIE; JACKSON, BRIAN R.; WHITEHOUSE, ADRIAN

    2014-01-01

    The γ-herpesviruses Epstein-Barr virus and Kaposi’s sarcoma-associated herpesvirus are successful pathogens, each infecting a large proportion of the human population. These viruses persist for the life of the host and may each contribute to a number of malignancies, for which there are currently no cures. Large-scale proteomic-based approaches provide an excellent means of increasing the collective understanding of the proteomes of these complex viruses and elucidating their numerous interactions within the infected host cell. These large-scale studies are important for the identification of the intricacies of viral infection and the development of novel therapeutics against these two important pathogens. PMID:25279171

  5. Intestinal Kaposi's sarcoma may mimic gastrointestinal stromal tumor in HIV infection.

    PubMed

    Zoufaly, A; Schmiedel, S; Lohse, A W; van Lunzen, J

    2007-09-07

    Diffuse intestinal Kaposi's sarcoma shares macroscopic and histopathologic features with gastrointestinal stromal tumors. Correct diagnosis may pose a clinical challenge. We describe the case of a young HIV-1-infected African lady without advanced immunodeficiency, who presented with a diffuse spindle cell tumor of the gut. Initial diagnosis was of a gastrointestinal stromal tumor, based on endoscopy and histopathology. Further evaluation revealed evidence for human herpesvirus 8 (HHV8) and the diagnosis had to be changed to diffuse intestinal Kaposi's sarcoma. Antiretroviral triple therapy together with chemotherapy was commenced, and has led to the rapid remission of intestinal lesions. With a background of HIV infection, the presence of HHV8 as the causative agent of Kaposi's sarcoma should be determined, as distinct treatment is indicated.

  6. Kaposi’s sarcoma herpesvirus/ Human herpesvirus-8 (KSHV/HHV8), and the oncogenesis of Kaposi’s sarcoma

    PubMed Central

    Mesri, Enrique A.; Cesarman, Ethel; Boshoff, Chris

    2016-01-01

    Kaposi’s sarcoma (KS) is the most common cancer in HIV-infected untreated individuals. Kaposi’s sarcoma-associated herpesvirus (KSHV; also known as human herpesvirus 8 (HHV8)) is the infectious cause of this neoplasm. In this Review we describe the epidemiology of KS and KSHV, and the insights into the remarkable mechanisms through which KSHV can induce KS that have been gained in the past 16 years. KSHV latent transcripts, such as latency-associated nuclear antigen (LANA), viral cyclin, viral FLIP and viral-encoded microRNAs, drive cell proliferation and prevent apoptosis, whereas KSHV lytic proteins, such as viral G protein-coupled receptor, K1 and virally encoded cytokines (viral interleukin-6 and viral chemokines) further contribute to the unique angioproliferative and inflammatory KS lesions through a mechanism called paracrine neoplasia. PMID:20865011

  7. What Should You Ask Your Doctor about Kaposi Sarcoma?

    MedlinePlus

    ... What Should You Ask Your Doctor About Kaposi Sarcoma? Kaposi Sarcoma Early Detection, Diagnosis, and Staging What Should You Ask Your Doctor About Kaposi Sarcoma? As you cope with Kaposi sarcoma (KS) and ...

  8. Bilateral tonsillar and esophageal Kaposi sarcoma in an HIV-negative patient.

    PubMed

    Ozbudak, Irem Hicran; Guney, Kenan; Mutlu, Derya; Gelen, Tekinalp; Ozbilim, Gulay

    2011-07-01

    Tonsillar involvement in Kaposi sarcoma is extremely rare, as only a few such cases have been reported; all but 1 of these previously reported cases occurred in patients with human immunodeficiency virus (HIV) infection. We describe what to the best of our knowledge is the first reported case of concurrent bilateral tonsillar and esophageal Kaposi sarcoma in an HIV-negative patient. A 68-year-old man presented with sore throat and dysphagia. Clinical examination revealed the presence of bilateral and asymmetrical tonsillar masses, as well as generalized lymphadenopathy in the cervical chain. The masses were resected, and findings on histopathologic analysis were consistent with Kaposi sarcoma. In addition, human herpesvirus 8 was demonstrated on a tonsil specimen by polymerase chain reaction, and microinvasive squamous cell carcinoma was also detected. Later, another Kaposi sarcoma lesion was detected in the lower third of the esophagus. We recommend that clinicians not discount the possibility of oral classic Kaposi sarcoma in the workup of an immunocompetent patient with oral vascular lesions.

  9. Pulmonary manifestations of human herpesvirus-8 during HIV infection.

    PubMed

    Borie, Raphael; Cadranel, Jacques; Guihot, Amélie; Marcelin, Anne Geneviève; Galicier, Lionel; Couderc, Louis-Jean

    2013-10-01

    Human herpesvirus (HHV)-8 is an oncogenic gamma herpesvirus that was first described in 1994 in Kaposi sarcoma lesions. HHV-8 is involved in the pathophysiological features of multicentric Castleman's disease (MCD) and primary effusion lymphoma (PEL), both rare B-cell lymphoproliferative diseases. HHV-8-related tumours occur almost exclusively in immunocompromised patients, mostly those with HIV infection. Combined antiretroviral therapies have reduced the incidence of Kaposi sarcoma but not MCD and PEL. HHV-8-related diseases frequently exhibit pulmonary involvement, which may indicate the disease. Kaposi sarcoma in the lung is often asymptomatic but may require specific therapy. It mostly shows cutaneous or mucosal involvement. Patients with typical MCD present fever and lymphadenopathy associated with interstitial lung disease without opportunistic infection. Specific treatment may be urgent. PEL provokes a febrile, lymphocytic-exudative pleural effusion, without a pleural mass on computed tomography scan. Rapid diagnosis prevents unnecessary examinations and leads to specific, rapid treatment. Therapy is complex, combining antiretroviral therapy and chemotherapy.

  10. Drugs Approved for Kaposi Sarcoma

    Cancer.gov

    This page lists cancer drugs approved by the Food and Drug Administration (FDA) for Kaposi sarcoma. The list includes generic names and brand names. The drug names link to NCI's Cancer Drug Information summaries.

  11. Herpesviruses that Infect Fish

    PubMed Central

    Hanson, Larry; Dishon, Arnon; Kotler, Moshe

    2011-01-01

    Herpesviruses are host specific pathogens that are widespread among vertebrates. Genome sequence data demonstrate that most herpesviruses of fish and amphibians are grouped together (family Alloherpesviridae) and are distantly related to herpesviruses of reptiles, birds and mammals (family Herpesviridae). Yet, many of the biological processes of members of the order Herpesvirales are similar. Among the conserved characteristics are the virion structure, replication process, the ability to establish long term latency and the manipulation of the host immune response. Many of the similar processes may be due to convergent evolution. This overview of identified herpesviruses of fish discusses the diseases that alloherpesviruses cause, the biology of these viruses and the host-pathogen interactions. Much of our knowledge on the biology of Alloherpesvirdae is derived from research with two species: Ictalurid herpesvirus 1 (channel catfish virus) and Cyprinid herpesvirus 3 (koi herpesvirus). PMID:22163339

  12. Skin Ultrasound in Kaposi Sarcoma.

    PubMed

    Carrascosa, R; Alfageme, F; Roustán, G; Suarez, M D

    2016-05-01

    The use of ultrasound imaging has recently been increasing in numerous dermatologic diseases. This noninvasive technique provides additional details on the structure and vascularization of skin lesions. Kaposi sarcoma is a vascular tumor that typically arises in the skin and mucosas. It can spread to lymph nodes and internal organs. We performed B-mode and color Doppler ultrasound studies in 3 patients with a clinical diagnosis of Kaposi sarcoma confirmed by histological examination. We found differences in the ultrasound pattern between nodular and plaque lesions, in both B-mode and color Doppler. We believe that skin ultrasound imaging could be a useful technique for studying cutaneous Kaposi sarcoma, providing additional information on the structural and vascular characteristics of the lesion.

  13. Immune reconstitution inflammatory syndrome, human herpesvirus 8 viremia, and HIV-associated multicentric Castleman disease.

    PubMed

    Siegel, Marc O; Ghafouri, Sanaz; Ajmera, Ravi; Simon, Gary L

    2016-07-01

    Kaposi's sarcoma and multicentric Castleman Disease are HIV-related disease processes that are associated with human herpesvirus 8 (HHV-8) infection. The development of multicentric Castleman disease can often be a manifestation of the immune reconstitution inflammatory syndrome phenomenon and is associated with markedly elevated levels of HHV-8 viremia, as illustrated by this case. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

  14. Steroids are a risk factor for Kaposi's sarcoma-immune reconstitution inflammatory syndrome and mortality in HIV infection

    PubMed Central

    Fernández-Sánchez, Mónica; Iglesias, María C.; Ablanedo-Terrazas, Yuria; Ormsby, Christopher E.; Alvarado-de la Barrera, Claudia; Reyes-Terán, Gustavo

    2016-01-01

    Objectives: To investigate the association between Kaposi's sarcoma-associated immune reconstitution inflammatory syndrome (KS-IRIS) and mortality, with the use of glucocorticoids in HIV-infected individuals. Design: Case–control study. Methods: We reviewed the medical records of 145 individuals with HIV-associated Kaposi's sarcoma receiving antiretroviral therapy. The association of different variables with KS-IRIS and Kaposi's sarcoma-related mortality was explored by univariate and multivariate analyses. The main exposure of interest was the use of glucocorticoids. We also compared the time to KS-IRIS and the time to death of individuals treated with glucocorticoids vs. those nontreated with glucocorticoids, and the time to death of individuals with KS-IRIS vs. those without KS-IRIS by hazards regression. Results: Sixty of 145 individuals received glucocorticoids (41.4%) for the management or suspicion of Pneumocystis jirovecii pneumonia. Fifty individuals had KS-IRIS (37%). The use of glucocorticoids was more frequent in individuals with KS-IRIS than in those without KS-IRIS (54.9 vs. 36.47%, P = 0.047). Kaposi's sarcoma-related mortality occurred in 17 cases (11.7%), and glucocorticoid use was more frequent in this group (76.47 vs. 36.7%, P = 0.003). Glucocorticoid use was a risk factor for mortality (adjusted odds ratio = 4.719, 95% confidence interval = 1.383–16.103, P = 0.0132), and was associated with shorter periods to KS-IRIS (P = 0.03) and death (P = 0.0073). KS-IRIS was a risk factor for mortality (P = 0.049). Conclusion: In HIV-infected individuals, the use of glucocorticoids is a risk factor for KS-IRIS and Kaposi's sarcoma-associated mortality. In addition, KS-IRIS is a risk factor for mortality. Therefore, glucocorticoid administration in this population requires careful consideration based on individualized risk–benefit analysis. PMID:26636923

  15. Early Establishment of γ-Herpesvirus Latency: Implications for Immune Control1

    PubMed Central

    Flaño, Emilio; Jia, Qingmei; Moore, John; Woodland, David L.; Sun, Ren; Blackman, Marcia A.

    2011-01-01

    The human γ-herpesviruses, EBV and Kaposi’s sarcoma-associated herpesvirus, infect >90% of the population worldwide, and latent infection is associated with numerous malignancies. Rational vaccination and therapeutic strategies require an understanding of virus-host interactions during the initial asymptomatic infection. Primary EBV infection is associated with virus replication at epithelial sites and entry into the circulating B lymphocyte pool. The virus exploits the life cycle of the B cell and latency is maintained long term in resting memory B cells. In this study, using a murine γ-herpesvirus model, we demonstrate an early dominance of latent virus at the site of infection, with lung B cells harboring virus almost immediately after infection. These data reinforce the central role of the B cell not only in the later phase of infection, but early in the initial infection. Early inhibition of lytic replication does not impact the progression of the latent infection, and latency is established in lymphoid tissues following infection with a replication-deficient mutant virus. These data demonstrate that lytic viral replication is not a requirement for γ-herpesvirus latency in vivo and suggest that viral latency can be disseminated by cellular proliferation. These observations emphasize that prophylactic vaccination strategies must target latent γ-herpesvirus at the site of infection. PMID:15814726

  16. What Are the Key Statistics about Kaposi Sarcoma?

    MedlinePlus

    ... Sarcoma About Kaposi Sarcoma What Are the Key Statistics About Kaposi Sarcoma? Before the AIDS epidemic, Kaposi ... and children. Visit the American Cancer Society’s Cancer Statistics Center for more key statistics. Written by References ...

  17. What's New in Kaposi Sarcoma Research and Treatment?

    MedlinePlus

    ... and Treatment? Kaposi Sarcoma About Kaposi Sarcoma What’s New in Kaposi Sarcoma Research and Treatment? A great ... once it has developed. Treatment Researchers are studying new and different ways to treat KS. Imiquimod (Aldara) ...

  18. Kaposi’s Sarcoma Herpesvirus Genome Persistence

    PubMed Central

    Juillard, Franceline; Tan, Min; Li, Shijun; Kaye, Kenneth M.

    2016-01-01

    Kaposi’s sarcoma-associated herpesvirus (KSHV) has an etiologic role in Kaposi’s sarcoma, primary effusion lymphoma, and multicentric Castleman’s disease. These diseases are most common in immunocompromised individuals, especially those with AIDS. Similar to all herpesviruses, KSHV infection is lifelong. KSHV infection in tumor cells is primarily latent, with only a small subset of cells undergoing lytic infection. During latency, the KSHV genome persists as a multiple copy, extrachromosomal episome in the nucleus. In order to persist in proliferating tumor cells, the viral genome replicates once per cell cycle and then segregates to daughter cell nuclei. KSHV only expresses several genes during latent infection. Prominent among these genes, is the latency-associated nuclear antigen (LANA). LANA is responsible for KSHV genome persistence and also exerts transcriptional regulatory effects. LANA mediates KSHV DNA replication and in addition, is responsible for segregation of replicated genomes to daughter nuclei. LANA serves as a molecular tether, bridging the viral genome to mitotic chromosomes to ensure that KSHV DNA reaches progeny nuclei. N-terminal LANA attaches to mitotic chromosomes by binding histones H2A/H2B at the surface of the nucleosome. C-terminal LANA binds specific KSHV DNA sequence and also has a role in chromosome attachment. In addition to the essential roles of N- and C-terminal LANA in genome persistence, internal LANA sequence is also critical for efficient episome maintenance. LANA’s role as an essential mediator of virus persistence makes it an attractive target for inhibition in order to prevent or treat KSHV infection and disease. PMID:27570517

  19. Solution structure of a Bcl-2 homolog from Kaposi sarcoma virus

    PubMed Central

    Huang, Qiulong; Petros, Andrew M.; Virgin, Herbert W.; Fesik, Stephen W.; Olejniczak, Edward T.

    2002-01-01

    Kaposi sarcoma-associated herpes virus (KSHV) contains a gene that has functional and sequence homology to the apoptotic Bcl-2 family of proteins [Sarid, R., Sato, T., Bohenzky, R. A., Russo, J. J. & Chang, Y. (1997) Nat. Med. 3, 293–298]. The viral Bcl-2 protein promotes survival of infected cells and may contribute to the development of Kaposi sarcoma tumors [Boshoff, C. & Chang, Y. (2001) Annu. Rev. Med. 52, 453–470]. Here we describe the solution structure of the viral Bcl-2 homolog from KSHV. Comparison of the KSHV Bcl-2 structure to that of Bcl-2 and Bcl-xL shows that although the overall fold is the same, there are key differences in the lengths of the helices and loops. Binding studies on peptides derived from the Bcl-2 homology region 3 of proapoptotic family members indicate that the specificity of the viral protein is very different from what was previously observed for Bcl-xL and Bcl-2, suggesting that the viral protein has evolved to have a different mechanism of action than the host proteins. PMID:11904405

  20. Iron: a target for the management of Kaposi's sarcoma?

    PubMed Central

    Simonart, Thierry

    2004-01-01

    Background Kaposi's sarcoma (KS) is a mesenchymal tumour associated with human herpesvirus-8 infection. However, the incidence of human herpesvirus-8 infection is far higher than the prevalence of KS, suggesting that viral infection per se is not sufficient for the development of malignancy and that one or more additional cofactors are required. Discussion Epidemiological data suggest that iron may be one of the cofactors involved in the pathogenesis of KS. Iron is a well-known carcinogen and may favour KS growth through several pathways. Based on the apoptotic and antiproliferative effect of iron chelation on KS cells, it is suggested that iron withdrawal strategies could be developed for the management of KS. Studies using potent iron chelators in suitable KS animal models are critical to evaluate whether iron deprivation may be a useful anti-KS strategy. Summary It is suggested that iron may be one of non-viral co-factors involved of KS pathogenesis and that iron withdrawal strategies might interfere with tumour growth in patients with KS. PMID:14725718

  1. Chemotherapy of herpesvirus infections.

    PubMed

    Jawetz, E

    1975-07-01

    Herpesviruses commonly produce lesions that come to the attention of physicians. Many different chemicals are known to suppress the growth of herpesviruses in vitro, but only a few of these have found application in clinical practice. A critical assessment of the place of some of these forms of chemotherapy was briefly presented.

  2. Gastrointestinal Kaposi sarcoma with appendiceal involvement.

    PubMed

    Egwuonwu, Steve; Gatto-Weis, Cara; Miranda, Roberto; Casas, Luis De Las

    2011-04-01

    Kaposi sarcoma is a vascular tumor manifesting as nodular lesions on skin, mucous membranes, or internal organs. This is a case of a 42-year-old human immunodeficiency virus- (HIV) positive bisexual male, not on highly active antiretroviral therapy (HAART) since diagnosis four years ago. He presented with a three-day history of abdominal pains, fever, vomiting, and a one-week history of melena stools. Endoscopy revealed Kaposi sarcoma in the stomach and duodenum. Postendoscopy, he developed acute abdomen. Exploratory laparotomy revealed extensive Kaposi sarcoma of the gastrointestinal tract with appendiceal involvement. The patient underwent appendectomy and had an uneventful recovery. A review of the literature discusses appendiceal Kaposi sarcoma with appendicitis, a rare but critical manifestation of gastrointestinal Kaposi sarcoma.

  3. Kaposi sarcoma in unusual locations

    PubMed Central

    Pantanowitz, Liron; Dezube, Bruce J

    2008-01-01

    Kaposi sarcoma (KS) is a multifocal, vascular lesion of low-grade malignant potential that presents most frequently in mucocutaneous sites. KS also commonly involves lymph nodes and visceral organs. This article deals with the manifestation of KS in unusual anatomic regions. Unusual locations of KS involvement include the musculoskeletal system, central and peripheral nervous system, larynx, eye, major salivary glands, endocrine organs, heart, thoracic duct, urinary system and breast. The development of KS within wounds and blood clots is also presented. KS in these atypical sites may prove difficult to diagnose, resulting in patient mismanagement. Theories to explain the rarity and development of KS in these unusual sites are discussed. PMID:18605999

  4. [AIDS-associated Kaposi's sarcoma: 22 cases].

    PubMed

    Dhrif, Asma Sioud; Kilani, Badreddine; Ammari, Lamia; Kanoun, Fakher; Tiouri, H; Ben Chaaben, Taoufik

    2007-06-01

    Kaposi's sarcoma is the most common acquired immune deficiency syndrome (AIDS)-associated malignancy. Our aim was to analyse the epidemiological, clinical, therapeutic findings in AIDS patients with Kaposi's sarcoma. This was a retrospective chart review of AIDS patients with Kaposi's sarcoma diagnosed between 1991 and 2005. Epidemiological data, the stage of human immunodeficiency virus's (HIV) infection, clinical characteristics of Kaposi's sarcoma, treatment rendered and outcome were collected. The search of HHV8 was not done. Twenty two patients were included. They were 17 men and 5 females (sex-ratio=3.4/ 1) with a mean age of 33.6 years at the diagnosis of HIV infection. The Kaposi's sarcoma appeared after a period varying between 0 and 10 years. The Kaposi's sarcoma uncovered the infection in 5 cases. There were 6 homosexual men. The mean rate of CD4 was 216 21/mm3 at the diagnosis of Kaposi's sarcoma. All patients had skin lesions. Mucocutaneous lesions were isolated in 12 cases and associated with visceral involvement in 10 cases; lung (10 cases), gastrointestinal tract (5 cases), lymphadenopathy (5 cases), liver (4 cases), spleen (2 cases). Antiretroviral therapy was prescribed for 13 patients. Six patients received chemotherapy and 3 others radiotherapy. Outcome was favourable in 4 cases with a partial improvement of the skin lesions in 3 cases and a complete regression in 1 case. Twelve patients died. AIDS associated Kaposi's sarcoma is a severe condition because of visceral localisations and the field of immunodeficiency. It requires a precocious diagnosis and collaboration. The identification of HHV8 in the aetiopathogenic mechanism of Kaposi's sarcoma can lead to the development new therapeutic approaches.

  5. Classic Kaposi's sarcoma in Italy, 1985–1998

    PubMed Central

    Dal Maso, L; Polesel, J; Ascoli, V; Zambon, P; Budroni, M; Ferretti, S; Tumino, R; Tagliabue, G; Patriarca, S; Federico, M; Vercelli, M; Giacomin, A; Vicario, G; Bellù, F; Falcini, F; Crocetti, E; De Lisi, V; Vitarelli, S; Piffer, S; Stracci, F; Serraino, D; Rezza, G; Franceschi, S

    2004-01-01

    To evaluate incidence rates (IRs) of classic Kaposi's sarcoma (CKS) in Italy after the spread of AIDS, we distinguished CKS from AIDS-related KS (AKS) using an ‘ad hoc' record linkage procedure between 15 Cancer Registries (CRs) (21% of the Italian population) and the national AIDS Registry. Between 1985 and 1998, 874 cases of CKS and 634 cases of AKS were diagnosed in the study areas. CKS accounted for 16 and 27% of KS cases below 55 years of age in men and women, respectively, but for 91 and 100% of those above age 55. The IRs for CKS were 1.0/ in men and 0.4/100 000 in women, but they varied between 0.3 in Umbria and 4.7 in Sassari in men, and between 0.1 in Parma and 1.7 in Sassari in women. IRs of CKS in both genders were stable between 1985–1987 and 1993–1998. In Northern and Central CRs the IR (adjusted for age and gender) for CKS was 0.5 in individuals born in the same area, but 1.6 in individuals born in Southern Italy or in the Islands (rate ratio=3.2) suggesting that KS-associated herpesvirus, the cause of KS, is acquired early in life. PMID:15570306

  6. Kaposi sarcoma herpes virus-associated hemophagocytic syndrome complicated by multicentric castleman disease and kaposi sarcoma in a HIV-negative immunocompetent patient: an autopsy case.

    PubMed

    Kim, Bomi; Jeon, Yoon Kyung; Kim, Chul Woo

    2009-10-01

    Kaposi sarcoma herpes virus (KSHV), also known as human herpesvirus-8, plays an important role in the pathogenesis of Kaposi sarcoma (KS), multicentric Castleman disease (MCD) of the plasma cell type, and primary effusion lymphoma. KSHV is rarely associated with the hemophagocytic syndrome (HPS), but when it does occur, it most occurs in immunocompromised patients. We report herein an unusual case of KSHV-associated HPS in an immunocompetent patient. A previously healthy 62-yr-old male was referred for evaluation of leukocytopenia and multiple lymphadenopathies. After a lymph node biopsy, he was diagnosed with MCD of the plasma cell type. KSHV DNA was detected in the lymph node tissue by polymerase chain reaction. Following a short-term response of the leukocytopenia to prednisolone, mental change, left side weakness, fever, thrombocytopenia, hemolytic anemia, and renal failure developed. Despite intravenous immunoglobulin therapy and plasmapheresis, he expired. The lymph nodes were infiltrated by hemophagocytic histiocytes in the sinuses. Pulmonary nodules and gastric erosions were shown to be KS. KSHV DNA was detected in the stomach, lung, and liver. This is the first case of multiple KSHV associated diseases including MCD and KS with KSHV-associated hemophagocytic syndrome in an HIV-negative, non-transplant, immunocompetent patient.

  7. Kaposi Sarcoma Herpes Virus-associated Hemophagocytic Syndrome Complicated by Multicentric Castleman Disease and Kaposi Sarcoma in a HIV-negative Immunocompetent Patient: An Autopsy Case

    PubMed Central

    Kim, Bomi; Kim, Chul Woo

    2009-01-01

    Kaposi sarcoma herpes virus (KSHV), also known as human herpesvirus-8, plays an important role in the pathogenesis of Kaposi sarcoma (KS), multicentric Castleman disease (MCD) of the plasma cell type, and primary effusion lymphoma. KSHV is rarely associated with the hemophagocytic syndrome (HPS), but when it does occur, it most occurs in immunocompromised patients. We report herein an unusual case of KSHV-associated HPS in an immunocompetent patient. A previously healthy 62-yr-old male was referred for evaluation of leukocytopenia and multiple lymphadenopathies. After a lymph node biopsy, he was diagnosed with MCD of the plasma cell type. KSHV DNA was detected in the lymph node tissue by polymerase chain reaction. Following a short-term response of the leukocytopenia to prednisolone, mental change, left side weakness, fever, thrombocytopenia, hemolytic anemia, and renal failure developed. Despite intravenous immunoglobulin therapy and plasmapheresis, he expired. The lymph nodes were infiltrated by hemophagocytic histiocytes in the sinuses. Pulmonary nodules and gastric erosions were shown to be KS. KSHV DNA was detected in the stomach, lung, and liver. This is the first case of multiple KSHV associated diseases including MCD and KS with KSHV-associated hemophagocytic syndrome in an HIV-negative, non-transplant, immunocompetent patient. PMID:19795003

  8. Structural Proteomics of Herpesviruses

    PubMed Central

    Leroy, Baptiste; Gillet, Laurent; Vanderplasschen, Alain; Wattiez, Ruddy

    2016-01-01

    Herpesviruses are highly prevalent viruses associated with numerous pathologies both in animal and human populations. Until now, most of the strategies used to prevent or to cure these infections have been unsuccessful because these viruses have developed numerous immune evasion mechanisms. Therefore, a better understanding of their complex lifecycle is needed. In particular, while the genome of numerous herpesviruses has been sequenced, the exact composition of virions remains unknown for most of them. Mass spectrometry has recently emerged as a central method and has permitted fundamental discoveries in virology. Here, we review mass spectrometry-based approaches that have recently allowed a better understanding of the composition of the herpesvirus virion. In particular, we describe strategies commonly used for proper sample preparation and fractionation to allow protein localization inside the particle but also to avoid contamination by nonstructural proteins. A collection of other important data regarding post-translational modifications or the relative abundance of structural proteins is also described. This review also discusses the poorly studied importance of host proteins in herpesvirus structural proteins and the necessity to develop a quantitative workflow to better understand the dynamics of the structural proteome. In the future, we hope that this collaborative effort will assist in the development of new strategies to fight these infections. PMID:26907323

  9. Seroprevalence of antibodies against human herpesvirus 8 in a population of renal transplant recipients at Hôtel-Dieu de Québec Hospital.

    PubMed

    Delorme, S; Houde, I; Deschênes, L

    2003-11-01

    We conducted a seroepidemiologic study to determine the prevalence of anti-human herpesvirus 8 antibodies in a renal transplant population at Hôtel-Dieu de Québec Hospital. Testing for immunoglobulin G antibodies against lytic and latent antigens was performed on serum samples from 150 renal transplant patients. Human immunodeficiency virus-positive patients with confirmed Kaposi's sarcoma were used as positive controls. None of the renal transplant patients tested positive.

  10. Seroprevalence of Antibodies against Human Herpesvirus 8 in a Population of Renal Transplant Recipients at Hôtel-Dieu de Québec Hospital

    PubMed Central

    Delorme, S.; Houde, I.; Deschênes, L.

    2003-01-01

    We conducted a seroepidemiologic study to determine the prevalence of anti-human herpesvirus 8 antibodies in a renal transplant population at Hôtel-Dieu de Québec Hospital. Testing for immunoglobulin G antibodies against lytic and latent antigens was performed on serum samples from 150 renal transplant patients. Human immunodeficiency virus-positive patients with confirmed Kaposi's sarcoma were used as positive controls. None of the renal transplant patients tested positive. PMID:14605164

  11. Pulmonary Kaposi Sarcoma: An Uncommon Cause of Respiratory Failure in the Era of Highly Active Antiretroviral Therapy—Case Report and Review of the Literature

    PubMed Central

    Hemmings, Stefan; Paul, Yonette; Habtegebriel, Yordanis; Polk, Octavius

    2016-01-01

    Kaposi Sarcoma (KS) is the most common malignancy associated with Acquired Immune Deficiency Syndrome (AIDS) and is caused by Human Herpesvirus 8 (HHV 8) or Kaposi Sarcoma Herpesvirus (KSHV). In about 90% of cases Kaposi Sarcoma is associated with cutaneous lesions; however visceral disease can occur in the absence of cutaneous involvement. In the era of Highly Active Antiretroviral Therapy (HAART), the incidence of KS has declined. Clinical features of pulmonary KS might be difficult to distinguish from pneumonia in the immunocompromised patients and could lead to diagnostic challenges. First-line treatment of KS is with HAART and the incidence has declined with its use. Systemic chemotherapy may play a role depending on the extent of the disease. We report the case of a young man who presented with pulmonary symptoms and was later found to have pulmonary KS. Interestingly this diagnosis was made in the absence of the classic skin lesions. His disease was complicated by progressive respiratory failure and he eventually died. PMID:27872774

  12. Hepatic Kaposi sarcoma: A case report and review of the literature

    PubMed Central

    Van Leer-Greenberg, Brett; Kole, Abhisake; Chawla, Saurabh

    2017-01-01

    Kaposi sarcoma (KS) is an aggressive cancer caused by human herpesvirus-8, primarily seen in immunocompromised patients. As opposed to the well-described cutaneous manifestations and pulmonary complications of KS, hepatic KS is rarely reported before death as most patients with hepatic KS do not manifest symptoms or evidence of liver injury. In patients with acquired immune deficiency syndrome, hepatic involvement of KS is present in 12%-24% of the population on incidental imaging and in approximately 35% of patients with cutaneous KS if an autopsy was completed after their death. Patients with clinically significant hepatic injury due to hepatic KS usually have an aggressive course of disease with hepatic failure often progressing to multi-organ failure and death. Here we report an unusual presentation of acute liver injury due to hepatic KS and briefly review the published literature on hepatic KS. PMID:28217255

  13. Hepatic Kaposi sarcoma: A case report and review of the literature.

    PubMed

    Van Leer-Greenberg, Brett; Kole, Abhisake; Chawla, Saurabh

    2017-02-08

    Kaposi sarcoma (KS) is an aggressive cancer caused by human herpesvirus-8, primarily seen in immunocompromised patients. As opposed to the well-described cutaneous manifestations and pulmonary complications of KS, hepatic KS is rarely reported before death as most patients with hepatic KS do not manifest symptoms or evidence of liver injury. In patients with acquired immune deficiency syndrome, hepatic involvement of KS is present in 12%-24% of the population on incidental imaging and in approximately 35% of patients with cutaneous KS if an autopsy was completed after their death. Patients with clinically significant hepatic injury due to hepatic KS usually have an aggressive course of disease with hepatic failure often progressing to multi-organ failure and death. Here we report an unusual presentation of acute liver injury due to hepatic KS and briefly review the published literature on hepatic KS.

  14. Kaposi sarcoma secondary to endogenous adrenocorticotropic hormone-dependent Cushing syndrome.

    PubMed

    Mayor-Ibarguren, A; Roldán-Puchalt, M C; Sancho-Bueso, T; Pérez-López, C; Álvarez-Linera, J; Frutos, R; Álvarez-Escolá, C; Regojo-Zapata, R; Beato-Merino, M J; Herranz-Pinto, P; Lecumberri, B

    2016-06-01

    Kaposi sarcoma (KS) is an angioproliferative tumour that develops as a result of an infection by human herpesvirus 8, which is considered a necessary cause but not sufficient. Other factors - genetic, immunological and environmental - might play a role in the development of the disease. We report a case of KS secondary to endogenous Cushing syndrome (ECS) due to a pituitary adenoma, an association that has been reported only once. We also conducted a search through the Medline and PubMed databases for cases involving KS and ECS, finding only three additional cases that shared common clinical and prognostic features with ours. ECS might favour the development of KS due to immunosuppression. Dermatologists and other clinicians should be aware of this association, as it might be an underdiagnosed condition. It also has an important impact on the management of KS, and based on this review it relies on a good prognosis when ECS is well controlled. © 2015 British Association of Dermatologists.

  15. Incidentally Detected Kaposi Sarcoma of Adrenal Gland with Anaplastic Features in an HIV Negative Patient

    PubMed Central

    Celik, Murat; Sen, Erdem; Cebeci, Hakan; Ata, Ozlem; Yavas, Cagdas

    2016-01-01

    Kaposi sarcoma (KS), a vascular tumor caused by infection with human herpesvirus 8 (HHV8), is a systemic disease that can present with cutaneous lesions with or without visceral involvement. Very few cases of KS, most of which were associated with AIDS, have been reported in the adrenal gland. Anaplastic transformation of KS is a rare clinical presentation known as an aggressive disease with local recurrence and metastatic potential. We report here a 47-year-old HIV negative male presented with extra-adrenal symptoms and had an incidentally detected anaplastic adrenal KS exhibited aggressive clinical course. To the best of our knowledge, this is the first case of anaplastic primary adrenal KS without mucocutaneous involvement but subsequently developed other side adrenal metastases in an HIV negative patient. PMID:27747121

  16. Human herpesvirus 6.

    PubMed Central

    Braun, D K; Dominguez, G; Pellett, P E

    1997-01-01

    Human herpesvirus 6 variant A (HHV-6A) and human herpesvirus 6 variant B (HHV-6B) are two closely related yet distinct viruses. These visuses belong to the Roseolovirus genus of the betaherpesvirus subfamily; they are most closely related to human herpesvirus 7 and then to human cytomegalovirus. Over 95% of people older than 2 years of age are seropositive for either or both HHV-6 variants, and current serologic methods are incapable of discriminating infection with one variant from infection with the other. HHV-6A has not been etiologically linked to any human disease, but such an association will probably be found soon. HHV-6B is the etiologic agent of the common childhood illness exanthem subitum (roseola infantum or sixth disease) and related febrile illnesses. These viruses are frequently active and associated with illness in immunocompromised patients and may play a role in the etiology of Hodgkin's disease and other malignancies. HHV-6 is a commensal inhabitant of brains; various neurologic manifestations, including convulsions and encephalitis, can occur during primary HHV-6 infection or in immunocompromised patients. HHV-6 and distribution in the central nervous system are altered in patients with multiple sclerosis; the significance of this is under investigation. PMID:9227865

  17. Risk of classic Kaposi sarcoma with residential exposure to volcanic and related soils in Sicily

    PubMed Central

    Pelser, Colleen; Dazzi, Carmelo; Graubard, Barry I.; Lauria, Carmela; Vitale, Francesco; Goedert, James J.

    2009-01-01

    Purpose Before AIDS, endemic (African) Kaposi sarcoma (KS) was noted to occur in volcanic areas and was postulated to result from dirt chronically embedded in the skin of the lower extremities. The primary cause of all KS types is KS-associated herpesvirus (KSHV) infection, but co-factors contribute to the neoplasia. We investigated whether residential exposure volcanic or related soils was associated with the risk of classic Kaposi sarcoma (cKS) in Sicily. Methods Risk of incident cKS (n=141) compared to population-based KSHV seropositive controls (n=123) was estimated for residential exposure to four types of soil, categorized with maps from the European Soil Database and direct surveying. Questionnaire data provided covariates. Results Residents in communities high in luvisols were approximately 2.7-times more likely to have cKS than those in communities with no luvisols. Risk was not specific for cKS on the limbs, but it was elevated approximately 4–5-fold with frequent bathing or tap water drinking in high luvisols communities. Risk was unrelated to communities high in andosols, tephra, or clay soils. Conclusions Iron and alumino-silicate clay, major components of luvisols, may increase cKS risk, but formal investigation and consideration of other soil types and exposures are needed. PMID:19576540

  18. AIDS-related Kaposi sarcoma: findings on thallium-201 scintigraphy

    SciTech Connect

    Lee, V.W.; Rosen, M.P.; Baum, A.; Cohen, S.E.; Cooley, T.P.; Liebman, H.A.

    1988-12-01

    No simple, noninvasive method is available for evaluating extracutaneous Kaposi sarcoma in AIDS patients or for following the tumor's response to treatment. We report our preliminary experience with thallium-201 scintigraphy in nine AIDS patients with proved Kaposi sarcoma. Eight of the nine had abnormal uptake of the radionuclide in skin, lymph nodes, oral cavity, vagina, and lungs. Only four of the nine had cutaneous Kaposi sarcoma at the time of scanning. All cutaneous and mucosal lesions were thallium avid. Two of the six patients with thallium-avid nodes underwent nodal biopsy. Both biopsies confirmed the diagnosis of Kaposi sarcoma. Cutaneous Kaposi sarcoma developed later in one of these patients, showing the efficacy of thallium scintigraphy for the early detection of extracutaneous lesions. These preliminary results show thallium avidity in Kaposi sarcoma involving the skin and various extracutaneous sites (lymph nodes, lung, mucosa, and vagina). Thallium scintigraphy is a potentially useful procedure for detecting extracutaneous Kaposi sarcoma in AIDS patients.

  19. Kaposi’s Sarcoma-Associated Herpesvirus (KSHV) Induces the Oncogenic miR-17-92 Cluster and Down-Regulates TGF-β Signaling

    PubMed Central

    Choi, Hong Seok; Jain, Vaibhav; Krueger, Brian; Marshall, Vickie; Kim, Chang Hee; Shisler, Joanna L.; Whitby, Denise; Renne, Rolf

    2015-01-01

    KSHV is a DNA tumor virus that causes Kaposi’s sarcoma. Upon KSHV infection, only a limited number of latent genes are expressed. We know that KSHV infection regulates host gene expression, and hypothesized that latent genes also modulate the expression of host miRNAs. Aberrant miRNA expression contributes to the development of many types of cancer. Array-based miRNA profiling revealed that all six miRNAs of the oncogenic miR-17-92 cluster are up-regulated in KSHV infected endothelial cells. Among candidate KSHV latent genes, we found that vFLIP and vCyclin were shown to activate the miR-17-92 promoter, using luciferase assay and western blot analysis. The miR-17-92 cluster was previously shown to target TGF-β signaling. We demonstrate that vFLIP and vCyclin induce the expression of the miR-17-92 cluster to strongly inhibit the TGF-β signaling pathway by down-regulating SMAD2. Moreover, TGF-β activity and SMAD2 expression were fully restored when antagomirs (inhibitors) of miR-17-92 cluster were transfected into cells expressing either vFLIP or vCyclin. In addition, we utilized viral genetics to produce vFLIP or vCyclin knock-out viruses, and studied the effects in infected TIVE cells. Infection with wildtype KSHV abolished expression of SMAD2 protein in these endothelial cells. While single-knockout mutants still showed a marked reduction in SMAD2 expression, TIVE cells infected by a double-knockout mutant virus were fully restored for SMAD2 expression, compared to non-infected TIVE cells. Expression of either vFLIP or vCycIin was sufficient to downregulate SMAD2. In summary, our data demonstrate that vFLIP and vCyclin induce the oncogenic miR-17-92 cluster in endothelial cells and thereby interfere with the TGF-β signaling pathway. Manipulation of the TGF-β pathway via host miRNAs represents a novel mechanism that may be important for KSHV tumorigenesis and angiogenesis, a hallmark of KS. PMID:26545119

  20. Reactivation and role of HHV-8 in Kaposi's sarcoma initiation.

    PubMed

    Ensoli, B; Stürzl, M; Monini, P

    2001-01-01

    Kaposi's sarcoma (KS) is an angioproliferative disease occurring in several clinical-epidemio-logic forms but all associated with infection by the human herpesvirus-8 (HHV-8). At least in early stages, KS is a reactive disease associated with a state of immune dysregulation characterized by CD8+ T-cell activation and production of Th1-type inflammatory cytokines (IC) that precedes lesion development. In fact, evidence indicates that IC can trigger lesion formation by inducing the activation of endothelial cells that leads to adhesion and tissue extravasation of lymphomonocytes, spindle cell formation, and angiogenesis, and HHV-8 reactivation that, in turn, leads to virus spread to all circulating cell types and virus dissemination into tissues. Due to virus escape mechanisms and deficient immune responses toward HHV-8, virus reactivation and spread are not controlled by the immune system but induce immune responses that may paradoxically exacerbate the reactive process. The virus is recruited into "activated" tissue sites where it finds an optimal environment for growth. In fact, viral load is very low in early lesions, whereas almost all spindle cells are infected in late-stage lesions. Although early KS is a reactive process of polyclonal nature that can regress, in time and in the presence of immunodeficiency, it can progress to a true sarcoma. This is likely due to the long-lasting expression of HHV-8 latency genes in spindle cells associated with the deregulated expression of oncogenes and oncosuppressor genes and, for AIDS-KS, with the effects of the HIV-1 Tat protein.

  1. Anguillid Herpesvirus 1 Transcriptome

    PubMed Central

    van Beurden, Steven J.; Gatherer, Derek; Kerr, Karen; Galbraith, Julie; Herzyk, Pawel; Peeters, Ben P. H.; Rottier, Peter J. M.; Engelsma, Marc Y.

    2012-01-01

    We used deep sequencing of poly(A) RNA to characterize the transcriptome of an economically important eel virus, anguillid herpesvirus 1 (AngHV1), at a stage during the lytic life cycle when infectious virus was being produced. In contrast to the transcription of mammalian herpesviruses, the overall level of antisense transcription from the 248,526-bp genome was low, amounting to only 1.5% of transcription in predicted protein-coding regions, and no abundant, nonoverlapping, noncoding RNAs were identified. RNA splicing was found to be more common than had been anticipated previously. Counting the 10,634-bp terminal direct repeat once, 100 splice junctions were identified, of which 58 were considered likely to be involved in the expression of functional proteins because they represent splicing between protein-coding exons or between 5′ untranslated regions and protein-coding exons. Each of the 30 most highly represented of these 58 splice junctions was confirmed by RT-PCR. We also used deep sequencing to identify numerous putative 5′ and 3′ ends of AngHV1 transcripts, confirming some and adding others by rapid amplification of cDNA ends (RACE). The findings prompted a revision of the AngHV1 genome map to include a total of 129 protein-coding genes, 5 of which are duplicated in the terminal direct repeat. Not counting duplicates, 11 genes contain integral, spliced protein-coding exons, and 9 contain 5′ untranslated exons or, because of alternative splicing, 5′ untranslated and 5′ translated exons. The results of this study sharpen our understanding of AngHV1 genomics and provide the first detailed view of a fish herpesvirus transcriptome. PMID:22787220

  2. Combination Therapy for Advanced Kaposi Sarcoma

    Cancer.gov

    In this clinical trial, adult patients with any form of advanced Kaposi sarcoma will be treated with liposomal doxorubicin and bevacizumab every 3 weeks for a maximum of six treatments.  Patients who respond to this therapy or have stable disease will rec

  3. Kaposi's varicelliform eruption: A case series

    PubMed Central

    Ferrari, Bruno; Taliercio, Vanina; Luna, Paula; Abad, María Eugenia; Larralde, Margarita

    2015-01-01

    Kaposi's varicelliform eruption is a rare and potentially fatal viral infection caused mainly by reactivation of herpes simplex virus. It concomitantly occurs with pre-existing skin conditions, mostly atopic dermatitis, so it is predominately found in children. We present a case series that includes four adults, familial cases, and previously healthy patients. We also highlight clinical features, associations and therapeutic options. PMID:26753139

  4. Kaposi's varicelliform eruption: A case series.

    PubMed

    Ferrari, Bruno; Taliercio, Vanina; Luna, Paula; Abad, María Eugenia; Larralde, Margarita

    2015-01-01

    Kaposi's varicelliform eruption is a rare and potentially fatal viral infection caused mainly by reactivation of herpes simplex virus. It concomitantly occurs with pre-existing skin conditions, mostly atopic dermatitis, so it is predominately found in children. We present a case series that includes four adults, familial cases, and previously healthy patients. We also highlight clinical features, associations and therapeutic options.

  5. Bell's palsy and herpesviruses.

    PubMed

    Gilbert, Stan C

    2002-12-01

    A growing body of evidence links reactivation of herpesviruses (primarily varicella zoster virus and herpes simplex virus type 1) with the development of a large proportion of cases of acute peripheral facial palsy, a syndrome commonly known by its eponym, Bell's palsy. This article reviews the definition and natural history of the disease, its underlying anatomy and pathophysiology, the data linking herpetic reactivation with development of signs and symptoms, and therapeutic trials utilizing antiviral therapy. In addition, it poses the question, would earlier intervention with antivirals make a larger impact on outcomes?

  6. Risk factors for classical Kaposi sarcoma in a population-based case-control study in Sicily

    PubMed Central

    Anderson, LA; Lauria, C; Romano, N; Brown, EE; Whitby, D; Graubard, BI; Li, Y; Messina, A; Gafà, L; Vitale, F

    2009-01-01

    Background Classical Kaposi sarcoma (cKS) is a rare complication of Kaposi sarcoma-associated herpes virus (KSHV) infection. We conducted a population-based, frequency-matched case-control study in Sicily to further investigate the reported inverse relationship between smoking and cKS and to identify other factors associated with altered risk. Methods All incident, histologically confirmed, cKS cases in Sicily were eligible. A two-stage cluster sample design was applied to select population controls. KSHV seropositivity was determined using 4 antibody assays (K8.1 and orf73 enzyme immunoassays and 2 immunofluroescence assays). Using SAS-callable SUDAAN we compared the characteristics of cKS cases and KSHV seropositive controls. Odds ratios (ORs) and 95% confidence intervals (CIs) are presented. Results In total, 142 cKS cases and 123 KSHV seropositive controls were recruited. Current cigarette smoking was associated with reduced risk of cKS (OR 0.20, 95% CI 0.06-0.67). Edema was associated with cKS, but only when it presented on the lower extremities (OR 3.65, 95% CI 1.62-8.23). Irrespective of presentation site, diabetes and oral corticosteroid medications were associated with increased risk (ORs, 95% CIs: 4.73, 2.02-11.1 and 2.34, 1.23-4.45, respectively). Never smoking, diabetes and oral corticosteroid medication use were all independently associated with cKS risk. Discussion We confirmed previous reports that cigarette smoking was associated with a reduced risk of cKS, and we found that risk was lowest among current smokers. We also found that cKS risk was strongly and independently associated with oral corticosteroid use and diabetes. Corroboration of these observations and investigation of possible underlying mechanisms are warranted. PMID:19064559

  7. Antiproliferative effects of Bortezomib in endothelial cells transformed by viral G protein-coupled receptor associated to Kaposi's sarcoma.

    PubMed

    Suares, A; Mori Sequeiros Garcia, M; Paz, C; González-Pardo, V

    2017-04-01

    The Kaposi's Sarcoma-associated Herpes virus G Protein-Coupled Receptor (vGPCR) is a key molecule in the pathogenesis of Kaposi Sarcoma. We have previously demonstrated that the proteasome inhibitor Bortezomib inhibits NF-κB pathway, which is required for tumor maintenance in endothelial cells that express vGPCR (vGPCR cells). In this work, we further investigated Bortezomib anti-proliferative mechanism of action. We demonstrated that Bortezomib decreases vGPCR cell number in a dose-dependent manner and induces cell morphology changes. Bortezomib decreases ERK1/2 phosphorylation whereas induces the accumulation of MKP-3 - a specific ERK1/2 MAP kinase phosphatase - in time and concentration dependent manner (1.5-32h; 0.25-1nM). The transcription factor FOXO1 is activated by dephosphorylation and regulates p21 expression. Here, we demonstrated that Bortezomib increases FOXO1 protein and decreases its phosphorylation in a concentration dependent manner (0.25-1nM). Bortezomib (0.5nM, 24h) also increase nuclear FOXO1 protein, in line with FOXO1 dephosphorylation induced by the drug. Consistent with FOXO1 dephosphorylation/activation, p21 mRNA expression is increased by Bortezomib in a MKP-3-dependent way. Bortezomib (0.5nM, 24h) also decreases VEGF, an ERK1/2 -dependent effect. It is concluded that in vGPCR cells, Bortezomib decreases ERK1/2 and FOXO1 phosphorylation through MKP-3 accumulation, leading ERK1/2 deactivation and FOXO1 activation respectively and, consequently, to cell proliferation inhibition, p21 induction and VEGF repression. Taken together, all these events contribute to the anti-tumoral effect of Bortezomib.

  8. The immunological relationship between canine herpesvirus and four other herpesviruses.

    PubMed

    Manning, A; Buchan, A; Skinner, G R; Durham, J; Thompson, H

    1988-07-01

    Canine herpesvirus (CHV) was compared with four other herpesviruses by several serological techniques. Cross-neutralization was demonstrated between CHV and herpes simplex virus types 1 and 2 and pseudorabies virus. Non-neutralizing cross-reactions were found with these viruses and also with equine abortion virus and bovine mammillitis virus. The data suggest that CHV is immunologically more closely related to herpes simplex virus than to the other viruses used in this study.

  9. [Classic and aggressive Kaposi sarcoma with bone involvement].

    PubMed

    Sbiyaa, Mouhcine; El Alaoui, Adil; El Bardai, Mohammed; Mezzani, Amine; Lahrach, Kamal; Marzouki, Amine; Boutayeb, Fawzi

    2016-01-01

    Classic Kaposi sarcoma is a multifocal rare tumor originating from vascular endothelial cells with progressive evolution and little malignant predisposition. Although Kaposi sarcoma with extensive visceral involvement is sometimes observed among HIV-positive patients, tumor dissemination to visceral lymph nodes in classic SK remains very rare. We report a rare case of aggressive classic Kaposi sarcoma of the hand with a rapid and destructive development.

  10. Dermoscopy of Kaposi's sarcoma: areas exhibiting the multicoloured 'rainbow pattern'.

    PubMed

    Hu, S C-S; Ke, C-L K; Lee, C-H; Wu, C-S; Chen, G-S; Cheng, S-T

    2009-10-01

    Kaposi's sarcoma is a vascular tumour characterized by a proliferation of spindle cells and endothelial cells to form closely arranged slit-like vascular spaces. Currently, the definitive diagnosis of Kaposi's sarcoma relies on histology. The dermoscopic features of Kaposi's sarcoma are not clearly defined in the scientific literature. We seek to evaluate the dermoscopic features of Kaposi's sarcoma and compare them with other vascular tumours. One hundred forty-one lesions from seven patients with histologically proven Kaposi's sarcoma were evaluated using polarized light dermoscopy for the presence of various dermoscopic features. Twenty patients with other vascular tumours were also examined. Dermoscopic examination revealed bluish-reddish coloration (84% of lesions), multicoloured areas showing various colours of the rainbow spectrum (36%), scaly surface (29%), and small brown globules (15%). The 'rainbow pattern' was found in six out of seven patients with Kaposi's sarcoma and was not observed in other vascular tumours. In addition, there was an absence of dermoscopic features specific for other vascular and non-vascular skin tumours, such as well-defined lacunae or structured vascular pattern, in most of the Kaposi's sarcoma lesions. The most frequent dermoscopic patterns in Kaposi's sarcoma were found to be bluish-reddish coloration, the 'rainbow pattern', and scaly surface. The rainbow pattern is a dermoscopic feature which has not been previously described. We propose that dermoscopy, as an adjunct to clinical examination, may enhance accuracy in the preoperative diagnosis of Kaposi's sarcoma.

  11. Cyprinid Herpesvirus 3

    PubMed Central

    Michel, Benjamin; Fournier, Guillaume; Lieffrig, François; Costes, Bérénice

    2010-01-01

    The recently designated cyprinid herpesvirus 3 (CyHV-3) is an emerging agent that causes fatal disease in common and koi carp. Since its emergence in the late 1990s, this highly contagious pathogen has caused severe financial losses in common and koi carp culture industries worldwide. In addition to its economic role, recent studies suggest that CyHV-3 may have a role in fundamental research. CyHV-3 has the largest genome among viruses in the order Herpesvirales and serves as a model for mutagenesis of large DNA viruses. Other studies suggest that the skin of teleost fish represents an efficient portal of entry for certain viruses. The effect of temperature on viral replication suggests that the body temperature of its poikilotherm host could regulate the outcome of the infection (replicative vs. nonreplicative). Recent advances with regard to CyHV-3 provide a role for this virus in fundamental and applied research. PMID:21122210

  12. Human herpesvirus 8-associated neoplasms: the roles of viral replication and antiviral treatment

    PubMed Central

    Gantt, Soren; Casper, Corey

    2014-01-01

    Purpose of review In this review, we highlight the importance of human herpesvirus 8 (HHV-8) lytic replication and the potential for antiviral therapies to prevent or treat HHV-8-related neoplasms. Recent findings Dieases caused by HHV-8 infection include Kaposi sarcoma (KS), multicentric Castleman disease (MCD), and primary effusion lymphoma (PEL), which occur primarily in patients with HIV infection. KS is the most common AIDS-associated malignancy worldwide. MCD and PEL occur less commonly but, like KS, are associated with poor treatment outcomes. Like all herpesviruses, HHV-8 is capable of either latent or lytic infection of cells. Although HHV-8 infection of tumor cells is predominately latent, accumulating data point to the importance of both lytic phase viral gene products and production of infectious virus. Antiviral agents that target herpesvirus DNA synthesis, such as ganciclovir, inhibit HHV-8 lytic replication and can prevent KS. Several HIV protease inhibitors may interfere with tumor growth and angiogenesis, and one PI, nelfinavir, directly inhibits HHV-8 replication in vitro. Summary Controlled trials are indicated to determine the clinical utility of antiviral suppression of HHV-8 replication, and identify the optimal antiretroviral regimens, for the prevention and treatment of KS. PMID:21666458

  13. Quantitative, Fluorogenic Probe PCR Assay for Detection of Human Herpesvirus 8 DNA in Clinical Specimens

    PubMed Central

    Stamey, Felicia R.; Patel, Mitesh M.; Holloway, Brian P.; Pellett, Philip E.

    2001-01-01

    A quantitative, fluorescence-based PCR assay (TaqMan-based system) was developed for detection of human herpesvirus 8 (HHV-8) DNA in clinical specimens. Primers and probes chosen from each of five 10-kb segments from the unique region of the HHV-8 genome were evaluated for sensitivity with dilution series of DNA extracted from a cell line (BCBL-1) that harbors HHV-8 DNA. Although several of the primer-probe sets performed similarly with BCBL-1 DNA that had been diluted in water, their performance differed when target DNA was diluted in a constant background of uninfected cell DNA, an environment more relevant to their intended use. The two best primer-probe combinations were specific for HHV-8 relative to the other known human herpesviruses and herpesvirus saimiri, a closely related gammaherpesvirus of nonhuman primates. PCRs included an enzymatic digestion step to eliminate PCR carryover and an exogenous internal positive control that enabled discrimination of false-negative from true-negative reactions. The new assays were compared to conventional PCR assays for clinical specimens (saliva, rectal brushings, rectal swab specimens, peripheral blood lymphocytes, semen, and urine) from human immunodeficiency virus-positive patients with or without Kaposi's sarcoma. In all instances, the new assays agreed with each other and with the conventional PCR system. In addition, the quantitative results obtained with the new assays were in good agreement both for duplicate reactions in the same assay and between assays. PMID:11574569

  14. Quantitative, fluorogenic probe PCR assay for detection of human herpesvirus 8 DNA in clinical specimens.

    PubMed

    Stamey, F R; Patel, M M; Holloway, B P; Pellett, P E

    2001-10-01

    A quantitative, fluorescence-based PCR assay (TaqMan-based system) was developed for detection of human herpesvirus 8 (HHV-8) DNA in clinical specimens. Primers and probes chosen from each of five 10-kb segments from the unique region of the HHV-8 genome were evaluated for sensitivity with dilution series of DNA extracted from a cell line (BCBL-1) that harbors HHV-8 DNA. Although several of the primer-probe sets performed similarly with BCBL-1 DNA that had been diluted in water, their performance differed when target DNA was diluted in a constant background of uninfected cell DNA, an environment more relevant to their intended use. The two best primer-probe combinations were specific for HHV-8 relative to the other known human herpesviruses and herpesvirus saimiri, a closely related gammaherpesvirus of nonhuman primates. PCRs included an enzymatic digestion step to eliminate PCR carryover and an exogenous internal positive control that enabled discrimination of false-negative from true-negative reactions. The new assays were compared to conventional PCR assays for clinical specimens (saliva, rectal brushings, rectal swab specimens, peripheral blood lymphocytes, semen, and urine) from human immunodeficiency virus-positive patients with or without Kaposi's sarcoma. In all instances, the new assays agreed with each other and with the conventional PCR system. In addition, the quantitative results obtained with the new assays were in good agreement both for duplicate reactions in the same assay and between assays.

  15. Kaposi's visceral sarcoma in liver transplant recipients.

    PubMed

    García-Sesma, A; Jiménez, C; Loinaz, C; Meneu, J C; Colina, F; Marqués, E; Gómez, R; Abradelo, M; Garcia, J I; Moreno González, E

    2003-08-01

    We report three cases of Kaposi's sarcoma after orthotopic liver transplantation performed for cirrhosis related to hepatitis C virus (one case), ethanol (one case), or both (one case). All patients displayed disease within the first year after liver transplantation, and only in one case was the diagnosis obtained before the patient died. All three patients were on tacrolimus-steroid therapy, and in one case mycophenolate mofetil was added to treat acute persistent rejection.

  16. Lymphangioma-like Kaposi sarcoma: case report.

    PubMed

    Posada García, Celia; García-Cruz, Aranzazu; García-Doval, Ignacio; De La Torre, Carlos; Cruces, Manuel José

    2009-09-15

    Kaposi sarcoma (KS) is a multifocal vascular disease with uncertain histogenesis. It is characterized by clinical and histologic polymorphism. The "lymphangioma-like" variant is very uncommon, accounting for less than 5% of all cases. We report the case of a 76-year-old woman, HIV negative, with a 4-year history of classic Kaposi sarcoma treated with cryotherapy who developed new bullous lesions on her lower extremities. Biopsy revealed histologic findings of lymphangioma-like KS (LLKS), together with areas of classic KS; HHV-8 staining was positive. Diagnosis of LLKS was made and the patient was proposed for radiotherapy. The lymphangioma-like Kaposi sarcoma is a rare morphologic expression of KS characterized by dilated and bizarrely shaped vascular channels lined by flattened endothelium permeating the dermis. "Bulla-like" lesions have been considered as a clinical hallmark of this variant. Its histologic appearance suggests a lymphatic origin of KS and it may resemble other vascular tumors. Findings of areas of typical KS and positive staining for HHV-8 may help to make a definitive diagnosis.

  17. Patterns of human herpesvirus-8 oral shedding among diverse cohorts of human herpesvirus-8 seropositive persons.

    PubMed

    Bender Ignacio, Rachel A; Goldman, Jason D; Magaret, Amalia S; Selke, Stacy; Huang, Meei-Li; Gantt, Soren; Johnston, Christine; Phipps, Warren T; Schiffer, Joshua T; Zuckerman, Richard A; McClelland, R Scott; Celum, Connie; Corey, Larry; Wald, Anna; Casper, Corey

    2016-01-01

    Human herpesvirus-8 (HHV-8), the etiologic agent of Kaposi sarcoma (KS), establishes lifelong latent infection with periodic lytic replication ("shedding") at mucosal sites, especially the oropharynx. Patterns of HHV-8 shedding are not well understood, and require elucidation to better predict risk of HHV-8 related malignancies in those infected. We sought to characterize patterns of HHV-8 oropharyngeal shedding among diverse cohorts that enrolled HHV-8 seropositive persons. We quantified HHV-8 oral shedding using PCR among HHV-8 seropositive persons who collected at least 14 days of oral swabs in 22 studies on 3 continents. We excluded persons taking antivirals during sampling or any prior use of antiretrovirals in those who were HIV-infected. 248 participants were enrolled from the US, Peru, Cameroon, Uganda, and Kenya; 61 % were men, 58 % were HIV seropositive, and 16 % had KS. Overall, 3,123 of 10,557 samples (29.6 %) had HHV-8 detected. Quantity of virus shed was highly correlated with shedding rate, (ρ = 0.72, p < 0.0001). HHV-8 was detected in ≥1 sample in 55 % of participants with a median of 7 % of days in the US and Kenya, 0 % in Uganda and Peru, and 18 % in Cameroon. Median episode duration was three days, and episodes with high median quantity lasted longer (42 vs 3 days, p < 0.0001). In persons with multiple observations over time, 66 % of shedding rate variance was attributable to differences between individuals. In HHV-8 infected individuals from diverse settings, oral mucosal shedding rate, quantity, and duration were correlated; individual shedding was highly variable. Studies are needed to determine factors accounting for between-person variation and the relationship of HHV-8 shedding to development of associated diseases.

  18. A neurotropic herpesvirus infecting the gastropod, abalone, shares ancestry with oyster herpesvirus and a herpesvirus associated with the amphioxus genome

    PubMed Central

    2010-01-01

    Background With the exception of the oyster herpesvirus OsHV-1, all herpesviruses characterized thus far infect only vertebrates. Some cause neurological disease in their hosts, while others replicate or become latent in neurological tissues. Recently a new herpesvirus causing ganglioneuritis in abalone, a gastropod, was discovered. Molecular analysis of new herpesviruses, such as this one and others, still to be discovered in invertebrates, will provide insight into the evolution of herpesviruses. Results We sequenced the genome of a neurotropic virus linked to a fatal ganglioneuritis devastating parts of a valuable wild abalone fishery in Australia. We show that the newly identified virus forms part of an ancient clade with its nearest relatives being a herpesvirus infecting bivalves (oyster) and, unexpectedly, one we identified, from published data, apparently integrated within the genome of amphioxus, an invertebrate chordate. Predicted protein sequences from the abalone virus genome have significant similarity to several herpesvirus proteins including the DNA packaging ATPase subunit of (putative) terminase and DNA polymerase. Conservation of amino acid sequences in the terminase across all herpesviruses and phylogenetic analysis using the DNA polymerase and terminase proteins demonstrate that the herpesviruses infecting the molluscs, oyster and abalone, are distantly related. The terminase and polymerase protein sequences from the putative amphioxus herpesvirus share more sequence similarity with those of the mollusc viruses than with sequences from any of the vertebrate herpesviruses analysed. Conclusions A family of mollusc herpesviruses, Malacoherpesviridae, that was based on a single virus infecting oyster can now be further established by including a distantly related herpesvirus infecting abalone, which, like many vertebrate viruses is neurotropic. The genome of Branchiostoma floridae (amphioxus) provides evidence for the existence of a herpesvirus

  19. Non-HIV-related Kaposi sarcoma in 2 Hispanic patients arising in the setting of chronic venous insufficiency.

    PubMed

    Que, Syril Kt; DeFelice, Taylor; Abdulla, Farah R; Cassarino, David; Patel, Rishi R

    2015-06-01

    Kaposi sarcoma (KS) is a vascular neoplasm associated with human herpesvirus 8 (HHV-8) infection that can be confused with the clinical and histological findings of chronic venous insufficiency. Definitive diagnosis of KS can only be achieved by performing a polymerase chain reaction for HHV-8 or by immunostaining for the HHV-8 antigen. We describe 2 unusual clinical presentations of KS in the setting of chronic venous insufficiency with clinical and histologic features consistent with stasis dermatitis but positive HHV-8 immunostaining. Both patients had no known risk factors for KS. We propose the possibility that these cases may represent a new clinical variant of KS that may become more prevalent over time. Further studies are needed to identify the risk factors involved. Meanwhile, skin biopsy with HHV-8 testing may be warranted for violaceous patches and plaques arising on the legs in the setting of chronic venous insufficiency, especially in patients who are unresponsive to treatment.

  20. Parma wallaby herpesvirus infection.

    PubMed

    Acland, H M

    1981-07-01

    Three Parma wallabies (Macropus parma) were inoculated with a herpesvirus recovered from a captive Parma wallaby with fatal naturally-occurring disease. Two intravenously inoculated animals died after 5 days and one animal infected via the conjunctiva and nasal mucosa was killed when moribund at 7 days. An additional two wallabies held in contact with the others became infected; they were killed at 11 days, when one was severely affected and one was mildly affected. All had small vesicles and ulcers of the skin of the upper and lower lips, eyelids, anogenital area and adjacent genital mucosa. Small vesicles and ulcers and large ulcers, with adherent necrotic epithelium and inflammatory debris, were present on the mucosa of the upper lips and adjacent gums and the conjunctiva. Numerous large basophilic or eosinophilic intranuclear inclusion bodies were observed in the epithelial cells of these vesicles and ulcers and of adjacent hair follicles and sebaceous glands. There was a mild to moderately severe rhinitis. Keratitis was present in two wallabies. Liver lesions were present in two animals but were unlike those seen in herpesviral hepatitis in other species.

  1. Ocular manifestations of feline herpesvirus.

    PubMed

    Andrew, S E

    2001-03-01

    Feline herpesvirus-1 (FHV-1) infection is ubiquitous in the domestic cat population worldwide. The most common clinical ocular manifestations of infection with FHV-1 are conjunctivitis and keratitis. This paper reviews the pathogenesis of feline herpesvirus-1 and discusses the various clinical ocular manifestations, diagnostic techniques and treatment of FHV-1-induced diseases. Ocular manifestations include: conjunctivitis, keratitis, stromal keratitis, keratoconjunctivitis sicca, ophthalmia neonatorium, symblepharon, corneal sequestrum, eosinophilic keratitis and anterior uveitis. Diagnostic techniques discussed include: virus isolation, fluorescent antibody testing, serum neutralising titers, ELISA and polymerase chain reaction. Various therapies are also discussed.

  2. Kaposi's Sarcoma and Human Herpesvirus 8 in Cuba: evidence of subtype B expansion.

    PubMed

    Kourí, Vivian; Martínez, Pedro A; Capó, Virginia; Blanco, Orestes; Rodríguez, María E; Jiménez, Narciso; Fleites, Gilberto; Caballero, Iraida; Dovigny, María C; Alemán, Yoan; Correa, Consuelo; Pérez, Lissette; Soto, Yudira; Cardellá, Lidia; Álvarez, Alina; Nambiar, Sandeep; Hengge, Ulrich

    2012-10-25

    To evaluate the temporal distribution (1991-2009) and associated variation of KSHV subtypes in Cuba. Phylogenetic characterization based on the KSHV K1 gene was performed using 90 KSHV positive samples. Molecular characterization confirmed the prevalence of a wide range of KSHV subtypes (A: n=48 [A5=12]; C: n=15; B: n=22; and E: n=5). In the current study, we observed a significant increase in HHV-8 subtype B after 2004 (p=0.0063). This Subtype B in Cuba was associated with: heterosexual behaviour (OR: 3.63, CI: 1,2-10,98; p=0.03), with the antecedent of acquiring HIV/KSHV in Africa (p=0.0003), with nodular stage of KS lesions (OR 4.2, CI: 1.1 to 15.7; p=0.04). Our study is the first to report KSHV Subtype B expansion in Cuba, that might be reflective of a change in human behavioural pattern. Copyright © 2012 Elsevier Inc. All rights reserved.

  3. Histological variants of cutaneous Kaposi sarcoma

    PubMed Central

    Grayson, Wayne; Pantanowitz, Liron

    2008-01-01

    This review provides a comprehensive overview of the broad clinicopathologic spectrum of cutaneous Kaposi sarcoma (KS) lesions. Variants discussed include: usual KS lesions associated with disease progression (i.e. patch, plaque and nodular stage); morphologic subtypes alluded to in the older literature such as anaplastic and telangiectatic KS, as well as several lymphedematous variants; and numerous recently described variants including hyperkeratotic, keloidal, micronodular, pyogenic granuloma-like, ecchymotic, and intravascular KS. Involuting lesions as a result of treatment related regression are also presented. PMID:18655700

  4. Kaposi sarcoma incidence in Mozambique: national and regional estimates.

    PubMed

    Meireles, Paula; Albuquerque, Gabriela; Vieira, Mariana; Foia, Severiano; Ferro, Josefo; Carrilho, Carla; Lunet, Nuno

    2015-11-01

    Kaposi sarcoma is expressed in four clinical variants, all associated with human herpes virus type 8 infection, namely, classic, endemic, immunosuppression-related and AIDS-related. The latter currently accounts for most of the burden of Kaposi sarcoma in sub-Saharan Africa, reflecting the frequency of HIV infection and its management. We aimed to estimate the incidence of Kaposi sarcoma in Mozambique and in its provinces. We estimated the number of incident cases of Kaposi sarcoma by adding up the expected number of endemic and AIDS-related cases. The former were estimated from the rates observed in Kyandondo, Uganda (1960-1971). The latter were computed from the number of AIDS-related deaths in each region, assuming that the ratio between the AIDS-related Kaposi sarcoma incident cases and the number of AIDS-related deaths observed in the city of Beira applies to all regions. A total of 3862 Kaposi sarcoma cases were estimated to have occurred in Mozambique in 2007, mostly AIDS-related, in the age group 25-49 years, and in provinces from South/Centre. The age-standardized incidence rates were 36.1/100 000 in men and 11.5/100 000 in women, with a more than three-fold variation across provinces. We estimated a high incidence of Kaposi sarcoma in Mozambique, along with large regional differences. These results can be used to improve disease management and to sustain political decisions on health policies.

  5. Pomalidomide for Symptomatic Kaposi's Sarcoma in People With and Without HIV Infection: A Phase I/II Study

    PubMed Central

    Polizzotto, Mark N.; Uldrick, Thomas S.; Wyvill, Kathleen M.; Aleman, Karen; Peer, Cody J.; Bevans, Margaret; Sereti, Irini; Maldarelli, Frank; Whitby, Denise; Marshall, Vickie; Goncalves, Priscila H.; Khetani, Vikram; Figg, William D.; Steinberg, Seth M.; Zeldis, Jerome B.

    2016-01-01

    Purpose Kaposi's sarcoma (KS) is a multicentric tumor caused by Kaposi's sarcoma–associated herpesvirus. Unmet needs include therapies that are oral, anthracycline sparing, and deliverable in resource-limited settings. We evaluated pomalidomide, an oral immune modulatory agent, in patients with symptomatic KS. Methods The primary objectives were to assess tolerability, pharmacokinetics, and activity. Initial dosage level was 5 mg once per day for 21 days per 28-day cycle, with a de-escalated level of 3 mg if not tolerable, and aspirin 81 mg once per day thromboprophylaxis. HIV-infected patients required controlled viremia with either persistent KS despite 3 months of antiretroviral therapy (ART) or progressive KS despite 2 months of ART. Evaluations included tumor response and health-related quality of life (HRQL). Results Twenty-two patients were treated; 15 (68%) were HIV infected, 17 (77%) had advanced (T1) disease, and 19 (86%) previous KS therapy excluding ART. All were treated with 5 mg because no dose-limiting toxicities occurred. Over 156 cycles, the grade 3/4 adverse events possibly attributable to therapy were neutropenia (23 cycles, 10 patients), infection (1 cycle), and edema (1 cycle). Sixteen patients responded (73%; 95% CI, 50% to 89%): nine of 15 HIV-infected patients (60%; 95% CI, 32% to 84%) and all seven HIV-uninfected patients (100%; 95% CI, 59% to 100%). Median time to response was 4 weeks (range, 4 to 36 weeks). HRQL showed no impairment during therapy and improved satisfaction with appearance at end therapy (P = .03). Significant increases in CD4+ and CD8+ cells were seen in patients with and without HIV, together with a transient increase in Kaposi's sarcoma–associated herpesvirus viral load at week 4 (P = .05). Conclusion Pomalidomide is well tolerated and active in KS regardless of HIV status. Responses were rapid, with improved self-reported outcomes, and occurred in advanced and heavily pretreated disease. Correlative studies support

  6. AIDS-related primary Kaposi sarcoma of the nasopharynx.

    PubMed

    Çelenk, Fatih; Yilmaz, Metin; Asal, Korhan; Ekinci, Özgür; Tokgöz, Nil

    2011-06-01

    Primary nasopharyngeal Kaposi sarcoma is extremely rare, as only 1 case has been previously reported in the literature. We report a new case, which occurred in a 37-year-old man with a known history of acquired immune deficiency syndrome (AIDS). The patient presented with complaints of recurrent epistaxis and postnasal hemorrhage. Endoscopic examination detected a bluish, smooth, firm, nonpulsatile mass in the nasopharyngeal wall. Histopathologic findings on biopsy were consistent with Kaposi sarcoma. The tumor was successfully treated with radiotherapy. Kaposi sarcoma should be considered in the differential diagnosis of any AIDS patient who presents with recurrent unilateral nasal bleeding.

  7. Pseudo-Kaposi sarcoma (acroangiodermatitis): occurring after bullous erysipelas.

    PubMed

    Kutlubay, Zekayi; Yardimci, Gürkan; Engin, Burhan; Demirkesen, Cuyan; Aydin, Övgü; Khatib, Rashid; Tuzun, Yalçın

    2015-05-18

    Pseudo-Kaposi sarcoma is a benign reactive vascular proliferative disorder, which can be seen at any age. It occurs when the chronic venous pressure changes result in vascular proliferation in the upper and mid dermis. This disease is divided into two subtypes: the most frequent subtype is the Mali type and seen in early ages. The Mali type is seen in chronic venous insufficiency and in those patients with arteriovenous shunts. The rare subtype is the Stewart-Bluefarb type. This disease must be distinguished from Kaposi sarcoma because of their clinical resemblance. Herein, we present a patient with pseudo-Kaposi sarcoma, which developed after bullous erysipelas.

  8. Epigenotypes of latent herpesvirus genomes.

    PubMed

    Minarovits, J

    2006-01-01

    Epigenotypes are modified cellular or viral genotypes which differ in transcriptional activity in spite of having an identical (or nearly identical) DNA sequence. Restricted expression of latent, episomal herpesvirus genomes is also due to epigenetic modifications. There is no virus production (lytic viral replication, associated with the expression of all viral genes) in tight latency. In vitro experiments demonstrated that DNA methylation could influence the activity of latent (and/or crucial lytic) promoters of prototype strains belonging to the three herpesvirus subfamilies (alpha-, beta-, and gamma-herpesviruses). In vivo, however, DNA methylation is not a major regulator of herpes simplex virus type 1 (HSV-1, a human alpha-herpesvirus) latent gene expression in neurons of infected mice. In these cells, the promoter/enhancer region of latency-associated transcripts (LATs) is enriched with acetyl histone H3, suggesting that histone modifications may control HSV-1 latency in terminally differentiated, quiescent neurons. Epstein-Barr virus (EBV, a human gamma-herpesvirus) is associated with a series of neoplasms. Latent, episomal EBV genomes are subject to host cell-dependent epigenetic modifications (DNA methylation, binding of proteins and protein complexes, histone modifications). The distinct viral epigenotypes are associated with distinct EBV latency types, i.e., cell type-specific usage of latent EBV promoters controlling the expression of latent, growth transformation-associated EBV genes. The contribution of major epigenetic mechanisms to the regulation of latent EBV promoters is variable. DNA methylation contributes to silencing of Wp and Cp (alternative promoters for transcripts coding for the nuclear antigens EBNA 1-6) and LMP1p, LMP2Ap, and LMP2Bp (promoters for transcripts encoding transmembrane proteins). DNA methylation does not control, however, Qp (a promoter for EBNA1 transcripts only) in lymphoblastoid cell lines (LCLs), although in vitro

  9. Fatal Outcome of Multiple Clinical Presentations of Human Herpesvirus 8-related Disease After Solid Organ Transplantation.

    PubMed

    Vijgen, Sandrine; Wyss, Caroline; Meylan, Pascal; Bisig, Bettina; Letovanec, Igor; Manuel, Oriol; Pascual, Manuel; de Leval, Laurence

    2016-01-01

    Kaposi sarcoma is the most common human herpesvirus 8 (HHV-8)-related disease described after solid organ transplantation. Multicentric Castleman disease and hemophagocytic syndrome are other potential HHV-8-induced entities but are less frequently reported. We describe the case of a liver transplant recipient who presented with an acute febrile illness 1 year after transplantation with a rapidly fatal outcome. Autopsy revealed 3 distinct HHV-8-related entities: Kaposi sarcoma, HHV-8-associated multicentric Castleman disease with microlymphomas and a severe hemophagocytic syndrome. Retrospective serologic tests suggested that HHV-8 was likely transmitted by the seropositive donor at the time of transplantation. To our knowledge, this is the first case of copresentation of 3 clinical presentations of HHV-8-mediated human disease in the post-transplant setting. Considering the absence of systematic screening of organ donors/recipients for HHV-8 infection, HHV-8-related illness should be suspected in transplant recipients who present with acute febrile illness, systemic symptoms, lymphadenopathies, and/or multiorgan failure to rapidly document the diagnosis and provide timely an adequate treatment.

  10. Cazenave, Kaposi and lupus erythematosus. A centennial and a sesquicentennial.

    PubMed

    Holubar, K; Fatović-Ferencić, S

    2001-01-01

    A review is presented calling attention to the first naming and publication of the term 'lupus erythematosus' and to the dermatologist (M. Kaposi) who first detected the systemic nature of this disease. Copyright 2001 S. Karger AG, Basel

  11. Herpesvirus BACs: past, present, and future.

    PubMed

    Warden, Charles; Tang, Qiyi; Zhu, Hua

    2011-01-01

    The herpesviridae are a large family of DNA viruses with large and complicated genomes. Genetic manipulation and the generation of recombinant viruses have been extremely difficult. However, herpesvirus bacterial artificial chromosomes (BACs) that were developed approximately 10 years ago have become useful and powerful genetic tools for generating recombinant viruses to study the biology and pathogenesis of herpesviruses. For example, BAC-directed deletion mutants are commonly used to determine the function and essentiality of viral genes. In this paper, we discuss the creation of herpesvirus BACs, functional analyses of herpesvirus mutants, and future applications for studies of herpesviruses. We describe commonly used methods to create and mutate herpesvirus BACs (such as site-directed mutagenesis and transposon mutagenesis). We also evaluate the potential future uses of viral BACs, including vaccine development and gene therapy.

  12. A New Transgenic Approach to Target Tumor Vasculature

    DTIC Science & Technology

    2006-06-01

    H. E. (1993). A receptor for subgroup A Rous sarcoma virus is related to the low density lipoprotein receptor. Cell 74, 1043-51. Bautch, V. L...Montaner, S., Sodhi, A., Servitja, J. M., Ramsdell, A. K., Barac, A., Sawai, E. T. and Gutkind, J. S. (2004). The small GTPase Rac1 links the Kaposi ... sarcoma -associated herpesvirus vGPCR to cytokine secretion and paracrine neoplasia. Blood 104, 2903-11. Mukouyama, Y. S., Shin, D., Britsch, S

  13. Cytokine-mediated growth promotion of Kaposi's sarcoma and primary effusion lymphoma.

    PubMed

    Ensoli, B; Stürzl, M; Monini, P

    2000-10-01

    Kaposi's sarcoma (KS) is an angioproliferative disease particularly frequent and aggressive in patients with AIDS but occurring also in post-transplant patients or in immunocompetent individuals of certain geographic areas. At least in its early stages, KS behaves as a reactive hyperplastic process mediated by inflammatory cytokines and angiogenic factors triggered or exacerbated by human herpesvirus-8 (HHV-8) infection. The HIV Tat protein appears to be responsible for the highly aggressive nature of AIDS-KS. Over time, however, KS may evolve into a true sarcoma in association with the expression of oncogenes and/or HHV-8 latency genes endowed with growth and anti-apoptotic properties. HHV-8 infection is also associated with primary effusion lymphoma (PEL), a rare tumor that similarly develops more frequently in the setting of HIV infection. HHV-8 latency genes are likely to contribute to the neoplastic phenotype of PEL cells, whose growth in vivo may require cytokines and factors from the host, or encoded by the virus.

  14. Whole-Genome Sequencing Identifies STAT4 as a Putative Susceptibility Gene in Classic Kaposi Sarcoma.

    PubMed

    Aavikko, Mervi; Kaasinen, Eevi; Nieminen, Janne K; Byun, Minji; Donner, Iikki; Mancuso, Roberta; Ferrante, Pasquale; Clerici, Mario; Brambilla, Lucia; Tourlaki, Athanasia; Sarid, Ronit; Guttman-Yassky, Emma; Taipale, Minna; Morgunova, Ekaterina; Pekkonen, Pirita; Ojala, Päivi M; Pukkala, Eero; Casanova, Jean-Laurent; Vaarala, Outi; Vahteristo, Pia; Aaltonen, Lauri A

    2015-06-01

    Classic Kaposi sarcoma (cKS) is an inflammatory tumor caused by human herpesvirus 8 (HHV-8) commonly observed in elderly men of Mediterranean origin. We studied a Finnish family of 5 affected individuals in 2 generations. Except for atypical mycobacterial infection of the index case, the affected individuals did not have notable histories of infection. We performed genome and exome sequencing and mapped shared chromosomal regions to identify genetic predisposition in the family. We identified 12 protein-coding candidate variants that segregated in the 3 affected cousins from whom we had samples. The affected mother of the index case was an obligatory carrier. Among the 12 candidates was a rare heterozygous substitution rs141331848 (c.1337C>T, p.Thr446Ile) in the DNA-binding domain of STAT4. The variant was not present in 242 Finnish control genomes or 180 additional regional controls. Activated T-helper cells from the HHV-8-negative variant carriers showed reduced interferon γ production, compared with age and sex matched wild-type individuals. We screened STAT4 in additional 18 familial KS cases and the variant site from 56 sporadic KS cases but detected no pathogenic mutations. Our data suggest that STAT4 is a potential cKS-predisposition gene, but further functional and genetic validation is needed. © The Author 2014. Published by Oxford University Press on behalf of the Infectious Diseases Society of America. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  15. Clinical exuberance of classic Kaposi's sarcoma and response to radiotherapy.

    PubMed

    Trujillo, Jeniffer Muñoz; Alves, Natália Ribeiro de Magalhães; Medeiros, Paula Mota; Azulay-Abulafia, Luna; Alves, Maria de Fátima Guimarães Scotelaro; Gripp, Alexandre Carlos

    2015-01-01

    Kaposi's sarcoma (KS) is a multicentric vascular neoplasm, with cutaneous and extracutaneous involvement. Different clinical and epidemiological variants have been identified. The classic form is manifested mainly in elderly men with indolent and long-term evolution, with lesions localized primarily in the lower extremities. We present two cases of classic Kaposi's sarcoma (CKS) in two female patients with extensive, exuberant skin involvement and rapid evolution, with good response to radiotherapy.

  16. Kaposi's sarcoma: DOX-SL approval recommended.

    PubMed

    1995-02-17

    The Food and Drug Administration (FDA) drug approval committee has recommended that DOX-SL be given accelerated approval for treatment of AIDS-related Kaposi's sarcoma (KS) in patients who have failed conventional treatment. This decision, coming after several votes against the drug's approval, brings up an ongoing problem with the current drug-approval system, i.e., the advisory committee for drug approvals has developed its own "corporate culture" for judging approval applications that can be disadvantageous to the smaller biotechnology company less familiar with the system. In order to prevent mistakes that may stop approval of a necessary drug, it may be necessary for the FDA to develop a body of knowledge, based on past experience with its committee system, to help committee members avoid certain perennial mistakes in drug approval.

  17. Primary Kaposi sarcoma of the subcutaneous tissue

    PubMed Central

    Pantanowitz, Liron; Mullen, John; Dezube, Bruce J

    2008-01-01

    Background Involvement of the subcutis by Kaposi sarcoma (KS) occurs primarily when cutaneous KS lesions evolve into deep penetrating nodular tumors. Primary KS of the subcutaneous tissue is an exceptional manifestation of this low-grade vascular neoplasm. Case presentation We present a unique case of acquired immune deficiency syndrome (AIDS)-associated KS manifesting primarily in the subcutaneous tissue of the anterior thigh in a 43-year-old male, which occurred without overlying visible skin changes or concomitant KS disease elsewhere. Radiological imaging and tissue biopsy confirmed the diagnosis of KS. Conclusion This is the first documented case of primary subcutaneous KS occurring in the setting of AIDS. The differential diagnosis of an isolated subcutaneous lesion in an human immunodeficiency virus (HIV)-infected individual is broad, and requires both imaging and a histopathological diagnosis to guide appropriate therapy. PMID:18764944

  18. Molecular Biology of Human Herpesvirus 8: Novel Functions and Virus–Host Interactions Implicated in Viral Pathogenesis and Replication

    PubMed Central

    Cousins, Emily; Nicholas, John

    2014-01-01

    Human herpesvirus 8 (HHV-8), also known as Kaposi’s sarcoma-associated herpesvirus (KSHV), is the second identified human gammaherpesvirus. Like its relative Epstein-Barr virus, HHV-8 is linked to B-cell tumors, specifically primary effusion lymphoma and multicentric Castleman’s disease, in addition to endothelial-derived KS. HHV-8 is unusual in its possession of a plethora of “accessory” genes and encoded proteins in addition to the core, conserved herpesvirus and gammaherpesvirus genes that are necessary for basic biological functions of these viruses. The HHV-8 accessory proteins specify not only activities deducible from their cellular protein homologies but also novel, unsuspected activities that have revealed new mechanisms of virus–host interaction that serve virus replication or latency and may contribute to the development and progression of virus-associated neoplasia. These proteins include viral interleukin-6 (vIL-6), viral chemokines (vCCLs), viral G protein–coupled receptor (vGPCR), viral interferon regulatory factors (vIRFs), and viral antiapoptotic proteins homologous to FLICE (FADD-like IL-1β converting enzyme)-inhibitory protein (FLIP) and survivin. Other HHV-8 proteins, such as signaling membrane receptors encoded by open reading frames K1 and K15, also interact with host mechanisms in unique ways and have been implicated in viral pathogenesis. Additionally, a set of micro-RNAs encoded by HHV-8 appear to modulate expression of multiple host proteins to provide conditions conducive to virus persistence within the host and could also contribute to HHV-8-induced neoplasia. Here, we review the molecular biology underlying these novel virus–host interactions and their potential roles in both virus biology and virus-associated disease. PMID:24008302

  19. Genome Sequence of Canine Herpesvirus

    PubMed Central

    Papageorgiou, Konstantinos V.; Suárez, Nicolás M.; Wilkie, Gavin S.; McDonald, Michael; Graham, Elizabeth M.; Davison, Andrew J.

    2016-01-01

    Canine herpesvirus is a widespread alphaherpesvirus that causes a fatal haemorrhagic disease of neonatal puppies. We have used high-throughput methods to determine the genome sequences of three viral strains (0194, V777 and V1154) isolated in the United Kingdom between 1985 and 2000. The sequences are very closely related to each other. The canine herpesvirus genome is estimated to be 125 kbp in size and consists of a unique long sequence (97.5 kbp) and a unique short sequence (7.7 kbp) that are each flanked by terminal and internal inverted repeats (38 bp and 10.0 kbp, respectively). The overall nucleotide composition is 31.6% G+C, which is the lowest among the completely sequenced alphaherpesviruses. The genome contains 76 open reading frames predicted to encode functional proteins, all of which have counterparts in other alphaherpesviruses. The availability of the sequences will facilitate future research on the diagnosis and treatment of canine herpesvirus-associated disease. PMID:27213534

  20. Inhibition of cGAS DNA Sensing by a Herpesvirus Virion Protein

    PubMed Central

    Wu, Jian-jun; Li, Wenwei; Shao, Yaming; Avey, Denis; Fu, Bishi; Gillen, Joseph; Hand, Travis; Ma, Siming; Liu, Xia; Miley, Wendell; Konrad, Andreas; Neipel, Frank; Stürzl, Michael; Whitby, Denise; Li, Hong; Zhu, Fanxiu

    2015-01-01

    SUMMARY Invading viral DNA can be recognized by the host cytosolic DNA sensor, cyclic GMP-AMP (cGAMP) synthase (cGAS), resulting in production of the second messenger cGAMP, which directs the adaptor protein STING to stimulate production of type I interferons (IFNs). Although several DNA viruses are sensed by cGAS, viral strategies targeting cGAS are virtually unknown. We report here that Kaposi’s sarcoma-associated herpesvirus (KSHV) ORF52, an abundant gammaherpesvirus-specific tegument protein, subverts cytosolic DNA sensing by directly inhibiting cGAS enzymatic activity through a mechanism involving both cGAS- and DNA-binding. Moreover, ORF52 homologues in other gammaherpesviruses also inhibit cGAS activity and similarly bind cGAS and DNA, suggesting conserved inhibitory mechanisms. Furthermore, KSHV infection evokes cGAS-dependent responses that can limit the infection, and an ORF52-null mutant exhibits increased cGAS signaling. Our findings reveal a mechanism through which gammaherpesviruses antagonize host cGAS DNA sensing. PMID:26320998

  1. Efficacy of paclitaxel in the treatment of Kaposi sarcoma.

    PubMed

    Ercolak, V; Sahin, B; Gunaldi, M; Duman, B B; Afsar, C U

    2015-11-01

    Kaposi sarcoma is an angioproliferative disease. Kaposi sarcoma is clinicopathologically classified into four subgroups based on epidemiological data. For its systemic treatment, in addition to some chemotherapeutics, taxanes have also been used during the recent years for their anti-angiogenic properties. In this study, we aimed to compare paclitaxel and non-paclitaxel chemotherapeutic regimens in terms of efficacy and side effects. In our center, demographical, clinical and histopathological characteristics of a total of 13 patients diagnosed with Kaposi sarcoma who received therapy were retrospectively recorded based on their medical files Among these subjects, 7 have been treated with paclitaxel and 6 with non-paclitaxel therapies. Eleven patients were male. Twelve patients were found to have classical type of Kaposi Sarcoma. The recurrence was observed in 2 patients treated with paclitaxel and in 1 patient treated with non-paclitaxel therapy. No statistically significant difference was found between the therapeutic modality, the stage of the disease and the percentage of the recurrence. Neuropathy developed in 3 patients treated with paclitaxel, whereas there was no neuropathy in the other group. Although the recurrence-free survival was worse in the patients treated with paclitaxel, there was no statistically significant difference. Cytotoxic chemotherapy is effective in treating patients with Kaposi Sarcoma, although it is palliative. Taxanes have demonstrated effectiveness against AIDS-associated Kaposi Sarcoma. The experience suggests that paclitaxel is an effective alternative in the treatment of classical form Kaposi's sarcoma. There was no difference in efficacy between paclitaxel and non-paclitaxel therapies whereas difference in occurrence of neuropathy which is one of the side effects, showed borderline statistical significance.

  2. Human herpesvirus infections: Pathogenesis, diagnosis, and treatment

    SciTech Connect

    Lopez, C.; Roizman, B.

    1986-01-01

    This book contains 24 selections. Some of the titles are: Molecular Biology of Latent HSV-1; Molecular Genetics of Antiviral Chemotherapy of Herpes Viruses; Molecular Basis of Foscarnet Action; Use of Vaccinia Virus as a Vector for Expression of Herpesvirus Genes; and Diagnosis of Herpesvirus with Monoclonal Antibodies.

  3. Production of a falcon herpesvirus vaccine.

    PubMed

    Wernery, U; Wernery, R; Kinne, J

    1999-09-01

    Ten common kestrels (Falco tinnunculus) were used for this falcon herpes vaccine experiment. Four kestrels were subcutaneously given 1 ml of an attenuated falcon herpesvirus that had originally been isolated from the liver of an American prairie falcon (Falco mexicanus). This virus was then passaged 100 times on chicken embryo fibroblast cells (CEF-cells). Another 4 kestrels were given subcutaneously an inactivated falcon herpesvirus vaccine derived from the same American field strain. This vaccine was concentrated, inactivated by heat and betapropiolactone and emulsified in complete Freund's adjuvans. Two further kestrels served as controls and were not vaccinated. Twenty-one days after vaccination, all 10 kestrels were challenged with passage 3 of the American falcon herpesvirus. The 2 control kestrels died 6 days after challenge and 3 of those given the inactivated herpes vaccine died 9 days after challenge, with typical lesions of herpesvirus inclusion body hepatitis. Before the vaccination experiment, all 10 kestrels were free of serum neutralising antibodies to the falcon herpesvirus. Twenty-one days after vaccination, all 4 kestrels vaccinated with the attenuated vaccine, and one vaccinated with the killed vaccine, had seroconverted, having shown no symptoms to the challenge with a low passage virulent American herpesvirus strain. Following the challenge their antibody titres to falcon herpesvirus increased. No herpesvirus was isolated from any of the cloacal swabs taken during this experiment, indicating that there is no danger for any other birds from the attenuated herpesvirus vaccine. This experiment clearly shows that an attenuated falcon herpesvirus vaccine can protect kestrels from fatal inclusion body hepatitis.

  4. Pulmonary involvement in Kaposi sarcoma: correlation between imaging and pathology.

    PubMed

    Gasparetto, Taisa Davaus; Marchiori, Edson; Lourenço, Sílvia; Zanetti, Gláucia; Vianna, Alberto Domingues; Santos, Alair A S M D; Nobre, Luiz Felipe

    2009-07-14

    Kaposi sarcoma is a low-grade mesenchymal tumor involving blood and lymphatic vessels. There are four variants of this disease, each presenting a different clinical manifestation: classic or sporadic, African or endemic, organ transplant-related or iatrogenic, and AIDS-related or epidemic. Kaposi sarcoma is the most common tumor among patients with HIV infection, occurring predominantly in homosexual or bisexual men. The pulmonary involvement in Kaposi sarcoma occurs commonly in critically immunosupressed patients who commonly have had preceding mucocutaneous or digestive involvement.The etiology of Kaposi sarcoma is not precisely established; genetic, hormonal, and immune factors, as well as infectious agents, have all been implicated. There is evidence from epidemiologic, serologic, and molecular studies that Kaposi sarcoma is associated with human herpes virus type 8 infection. The disease starts as a reactive polyclonal angioproliferative response towards this virus, in which polyclonal cells change to form oligoclonal cell populations that expand and undergo malignant transformation.The diagnosis of pulmonary involvement in Kaposi sarcoma usually can be made by a combination of clinical, radiographic, and laboratory findings, together with the results of bronchoscopy and transbronchial biopsy. Chest high-resolution computed tomography scans commonly reveal peribronchovascular and interlobular septal thickening, bilateral and symmetric ill-defined nodules in a peribronchovascular distribution, fissural nodularity, mediastinal adenopathies, and pleural effusions. Correlation between the high-resolution computed tomography findings and the pathology revealed by histopathological analysis demonstrate that the areas of central peribronchovascular infiltration represent tumor growth involving the bronchovascular bundles, with nodules corresponding to proliferations of neoplastic cells into the pulmonary parenchyma. The interlobular septal thickening may represent

  5. Hidden Pictures of Kaposi's Sarcoma in Psoriatic Lesions: A Diagnostic Challenge

    PubMed Central

    Yoo, Jisook; Jo, Mingyul; Kim, Min-Soo; Choi, Kwang-Hyun; Park, Hyang-Joon

    2016-01-01

    Kaposi's sarcoma is a multifocal proliferative vascular tumor involving the skin and other organ and psoriasis is a chronic cutaneous disease with papules and plaques with white scale. Development of Kaposi's sarcoma in psoriasis patients has been reported rarely. A 71-year-old man presented with multiple brownish to violaceous plaques on both feet and arms which were found 4 months ago. The biopsy confirmed Kaposi's sarcoma. The patient was diagnosed with psoriasis vulgaris 10 years ago and Kaposi's sarcoma lesions developed between psoriatic plaques. We herein report a rare case of simultaneous occurrence of Kaposi's sarcoma and psoriasis vulgaris which need quite different treatment. PMID:27904275

  6. Characterization of a caprine herpesvirus.

    PubMed

    Berrios, P E; McKercher, D G

    1975-12-01

    A virus, which was isolated from kids (Capra hircus) affected with a relatively severe generalized infection, was found to contain DNA and to have a buoyant density of 1.2820 g/cm3. The virus was sensitive to the action of lipid solvents and trypsin and was rapidly inactivated at pH 3.0 and at temperatures of 50 and 56 C. The virion, an icosahedron consisting of a nucleoid surrounded by a double membrane, measured approximately 135 nm in diameter. On the basis of its chemical and physical properties, the virus is considered a herpesvirus.

  7. [Oral lesions in Kaposi sarcoma: clinical and radiotherapeutic considerations].

    PubMed

    Barberis, M; Brenna Betti, N; Lauritano, D; Sangiani, L; Spadari, F; Villa, S

    1996-01-01

    The epidemic form of Kaposi's sarcoma is the most frequent tumor in sieropositive patients. Every part of the body including oral cavity is affected by these lesions. According to modern acknowledgement in treating oropharynge carcinoma, radiotherapy is used for management of oral Kaposi's sarcoma. This paper reports a study of 10 patients suffering from Kaposi's sarcoma correlated to AIDS (EKS) treated with radiotherapy and chemiotherapy, achieving good results, at the Istituto Nazionale per lo Studio e la Cura dei Tumori of Milan (Divisone di Radioterapia C) from 1988 to 1992. Treatment has been performed using linear accelerator (6 Mev) or Co 60 unity in order to reach the deepest layer of mucosa lesions. Radiotherapy schedule consisted of 150-200 cGy daily fractions given 5 times/week (w) for 4-5 w in split-course.

  8. p120-catenin regulates VE-cadherin endocytosis and degradation induced by the Kaposi sarcoma–associated ubiquitin ligase K5

    PubMed Central

    Nanes, Benjamin A.; Grimsley-Myers, Cynthia M.; Cadwell, Chantel M.; Robinson, Brian S.; Lowery, Anthony M.; Vincent, Peter A.; Mosunjac, Marina; Früh, Klaus; Kowalczyk, Andrew P.

    2017-01-01

    Vascular endothelial (VE)-cadherin undergoes constitutive internalization driven by a unique endocytic motif that also serves as a p120-catenin (p120) binding site. p120 binding masks the motif, stabilizing the cadherin at cell junctions. This mechanism allows constitutive VE-cadherin endocytosis and recycling to contribute to adherens junction dynamics without resulting in junction disassembly. Here we identify an additional motif that drives VE-cadherin endocytosis and pathological junction disassembly associated with the endothelial-derived tumor Kaposi sarcoma. Human herpesvirus 8, which causes Kaposi sarcoma, expresses the MARCH family ubiquitin ligase K5. We report that K5 targets two membrane-proximal VE-cadherin lysine residues for ubiquitination, driving endocytosis and down-regulation of the cadherin. K5-induced VE-cadherin endocytosis does not require the constitutive endocytic motif. However, K5-induced VE-cadherin endocytosis is associated with displacement of p120 from the cadherin, and p120 protects VE-cadherin from K5. Thus multiple context-dependent signals drive VE-cadherin endocytosis, but p120 binding to the cadherin juxtamembrane domain acts as a master regulator guarding cadherin stability. PMID:27798235

  9. Kaposi's Sarcoma in Uganda: Geographic and Ethnic Distribution

    PubMed Central

    Taylor, J. F.; Smith, P. G.; Bull, Diana; Pike, M. C.

    1972-01-01

    Over the quinquennium 1964-68 the crude annual incidence of Kaposi's sarcoma in Uganda per million of the population was 7·9 overall, 14·6 for males and 1·1 for females. Statistical analysis indicates that the disease is most prevalent in highland areas to the west and among the indigenous Bantu tribes. There was no correlation with the distribution of squamous cell carcinoma of the lower leg, and Kaposi's sarcoma was not seen in an Indian or European during the period under review. PMID:4647399

  10. Using Proteomics to Identify Viral microRNA-Regulated Genes | Center for Cancer Research

    Cancer.gov

    Kaposi sarcoma is a soft tissue malignancy that affects the skin, the mucous membranes, the lymph nodes and other organs of individuals with compromised immune systems. It is caused by infection with human herpesvirus-8 also known as Kaposi sarcoma-associated herpesvirus or KSHV. The herpesvirus family is unique in that it is the only viral family currently known to express multiple microRNAs (miRNAs); KSHV produces 12 pre-miRNAs, which are processed into at least 25 mature miRNAs. While their functions are not well understood, these miRNAs may be a way for the virus to alter the host immune response without producing proteins that could be recognized and targeted by the immune system. Joseph Ziegelbauer, Ph.D., in CCR’s HIV and AIDS Malignancy Branch, and his colleagues set out to identify human targets of KSHV miRNAs and to understand their functional importance.

  11. Rapamycin with Antiretroviral Therapy in AIDS-Associated Kaposi Sarcoma: An AIDS Malignancy Consortium Study

    PubMed Central

    Krown, Susan E.; Roy, Debasmita; Lee, Jeannette Y.; Dezube, Bruce J.; Reid, Erin G.; Venkataramanan, Raman; Han, Kelong; Cesarman, Ethel; Dittmer, Dirk P.

    2011-01-01

    Purpose The mammalian target of rapamycin (mTOR) is activated in Kaposi sarcoma (KS) and its inhibitor, rapamycin, has induced KS regression in transplant-associated KS. This study aimed to evaluate rapamycin's safety and toxicity in HIV-infected individuals with KS receiving antiretroviral therapy (ART), investigate rapamycin interactions with both protease inhibitor (PI)-containing and non-nucleoside reverse transcriptase inhibitor (NNRTI)-containing ART regimens, and assess clinical and biological endpoints including KS response and mTOR-dependent signaling. Methods Seven participants, 4 on PI-based and 3 on NNRTI-based ART, had rapamycin titrated to achieve trough concentrations of 5-10 ng/mL. Patients were monitored for safety and KS response. KS biopsies were evaluated for changes in phospho-Ribosomal S6 protein (pRPS6), and phospho-Akt expression. Interleukin-6 and vascular endothelial growth factor levels, HIV and KS-associated herpesvirus viral loads, and CD4 counts were monitored. Results Despite pharmacokinetic interactions resulting in >200-fold differences in cumulative weekly rapamycin doses between participants on PI-containing and NNRTI-containing regimens, treatment was well tolerated. There were no significant changes in viral loads or cytokine levels; modest initial decreases in CD4 counts occurred in some patients. Three participants, all on PI-containing regimens and with higher rapamycin exposure, showed partial KS responses. Three of four subjects whose biopsies were studied at ≥day 50 showed decreased pRPS6 staining. Conclusions Rapamycin appears safe in HIV-infected individuals with KS and can, in some cases, induce tumor regression and affect its molecular targets. Significant pharmacokinetic interactions require careful titration to achieve target drug trough concentrations, but may be exploited to achieve therapeutic benefit. PMID:22067664

  12. The Kynurenine Pathway of Tryptophan Catabolism and AIDS-Associated Kaposi Sarcoma in Africa.

    PubMed

    Byakwaga, Helen; Hunt, Peter W; Laker-Oketta, Miriam; Glidden, David V; Huang, Yong; Bwana, Bosco M; Mocello, A Rain; Bennett, John; Walusansa, Victoria; Dollard, Sheila C; Bangsberg, David R; Mbidde, Edward K; Martin, Jeffrey N

    2015-11-01

    Other than Kaposi sarcoma (KS)-associated herpesvirus and CD4 T-cell lymphopenia, the mechanisms responsible for KS in the context of HIV are poorly understood. One recently explored pathway of HIV pathogenesis involves induction of the enzyme indoleamine 2,3-dioxygenase-1 (IDO), which catabolizes tryptophan into kynurenine and several other immunologically active metabolites that suppress T-cell proliferation. We investigated the role of IDO in the development of KS in HIV disease. In a case-control study among untreated HIV-infected Ugandans, cases were adults with KS and controls were without KS. IDO activity was assessed by the ratio of plasma kynurenine to tryptophan levels (KT ratio), measured by liquid chromatography-tandem mass spectrometry. We studied 631 HIV-infected subjects: 222 KS cases and 409 controls. Non-KS controls had a higher median plasma KT ratio (130, interquartile range: 90 to 190 nM/μM) than KS cases (110, interquartile range: 90 to 150 nM/μM) (P = 0.004). After adjustment for age, sex, CD4 count, and plasma HIV RNA level, subjects with the highest (fourth quartile) plasma KT ratios had a 59% reduction (95% confidence interval: 27% to 77%) in the odds of KS compared with those with the lowest (first quartile) levels. KS was also independently associated with lower CD4 count, higher plasma HIV RNA, and men. Among HIV-infected individuals, greater activity of the kynurenine pathway of tryptophan catabolism, as evidenced by higher levels of plasma KT ratio, was associated with lower occurrence of KS. Some consequences of immune activation in HIV infection might actually suppress certain cancers.

  13. Clinical Presentation and Outcome of Epidemic Kaposi Sarcoma in Ugandan Children

    PubMed Central

    Gantt, Soren; Kakuru, Abel; Wald, Anna; Walusansa, Victoria; Corey, Lawrence; Casper, Corey; Orem, Jackson

    2009-01-01

    Background Kaposi sarcoma (KS) is one of the most common pediatric cancers in sub-Saharan Africa. Few data are available about the clinical presentation or response to treatment of children with epidemic (HIV-associated) KS. Methods Medical records of all children with KS and HIV infection referred to the Uganda Cancer Institute in Kampala, Uganda from October 2004 to June 2007 were reviewed. Charts were abstracted for age, sex, location of KS lesions at presentation, biopsy results, CD4 T-cell count and percentage, and KS treatment and outcome. Results Seventy-three children with epidemic KS were identified, 37 males and 36 females. The median age was 10.1 years (range 2 - 18). KS presented with lymph node involvement in 60% of cases. The median absolute and percentage CD4 T-cells at presentation were 210 cells/uL and 7.4%, respectively. Those children with lymphadenopathic KS were younger (mean difference 3.7 years; p = 0.01) and had higher CD4 T-cell counts (mean difference 242 cells/uL; p = 0.03) than those without lymph node involvement. Of 32 patients for whom outcome data were available, a complete response to chemotherapy and/or antiretroviral therapy was documented in 20 (62.5%) patients. Conclusions In comparison to cutaneous involvement, lymph node involvement of epidemic KS occurs at younger ages and at higher CD4 levels. This clinical presentation may reflect recent infection with human herpesvirus 8 followed by a rapid progression to malignancy. Favorable response to treatment was observed in the majority of cases, but prospective studies are needed to determine optimal management. PMID:20205254

  14. Clinical presentation and outcome of epidemic Kaposi sarcoma in Ugandan children.

    PubMed

    Gantt, Soren; Kakuru, Abel; Wald, Anna; Walusansa, Victoria; Corey, Lawrence; Casper, Corey; Orem, Jackson

    2010-05-01

    Kaposi sarcoma (KS) is one of the most common pediatric cancers in sub-Saharan Africa. Few data are available about the clinical presentation or response to treatment of children with epidemic (HIV-associated) KS. Medical records of all children with KS and HIV infection referred to the Uganda Cancer Institute in Kampala, Uganda from October 2004 to June 2007 were reviewed. Charts were abstracted for age, sex, location of KS lesions at presentation, biopsy results, CD4 T-cell count and percentage, and KS treatment and outcome. Seventy-three children with epidemic KS were identified, 37 males and 36 females. The median age was 10.1 years (range 2-18). KS presented with lymph node (LN) involvement in 60% of cases. The median absolute and percentage CD4 T-cells at presentation were 210 cells/microl and 7.4%, respectively. Those children with lymphadenopathic KS were younger (mean difference 3.7 years; P = 0.01) and had higher CD4 T-cell counts (mean difference 242 cells/microl; P = 0.03) than those without LN involvement. Of 32 patients for whom outcome data were available, a complete response to chemotherapy and/or antiretroviral therapy was documented in 20 (62.5%) patients. In comparison to cutaneous involvement, LN involvement of epidemic KS occurs at younger ages and at higher CD4 levels. This clinical presentation may reflect recent infection with human herpesvirus 8 followed by a rapid progression to malignancy. Favorable response to treatment was observed in the majority of cases, but prospective studies are needed to determine optimal management.

  15. Asymptomatic Pulmonary Allograft Kaposi Sarcoma: A Case Report.

    PubMed

    Nannini, Nazarena; Rebusso, Alessandro; Lunardi, Francesca; Loy, Monica; Calabrese, Francesca; Battistella, Lucia; Schiavon, Marco; Rea, Federico; Calabrese, Fiorella

    2016-01-14

    Solid-organ transplant recipients are at high risk of developing malignancies. A greater risk of Kaposi sarcoma has been reported in lung recipients in our country, particularly in those from Southern Italy, probably due to the high prevalence of Human herpes virus 8 infection. Kaposi sarcoma affecting only the lung allograft is extremely rare. We describe a case of a lung recipient who developed Kaposi sarcoma only in the graft, 22 months after transplant. The patient, a 65-year-old man from Southern Italy, underwent bilateral lung transplant for idiopathic pulmonary fibrosis in January 2009. He developed mild/moderate acute cellular rejection (≥A2) in 4 of 6 scheduled transbronchial biopsies thus was treated with increased immunosuppressive therapy, shifting from cyclosporine to tacrolimus and mycophenolate mofetil. In July 2010, a high-resolution computed tomography scan showed small bilateral lung nodules, despite a generally good condition. After 2 months, his condition worsened with a severe weight loss. A positron emission tomography scan showed mild metabolic activity in the lesions with no other localizations. In October 2010, a lung biopsy was performed, with results showing typical histologic and immunohistochemical features of Kaposi sarcoma. Molecular tissue evaluations and serologic analyses were positive for Human herpes virus 8. The patient's immunosuppressive therapy was suspended, and he started liposomal doxorubicin treatment; however, after the first cycle, he developed severe respiratory dysfunction. The patient died 27 months after lung transplant for neoplasm. Our report highlights the importance of considering Kaposi sarcoma in the differential diagnosis for lung nodules in lung transplant recipients, even in the absence of any initial specific symptom or cutaneous lesion.

  16. Close but Distinct Regions of Human Herpesvirus 8 Latency-Associated Nuclear Antigen 1 Are Responsible for Nuclear Targeting and Binding to Human Mitotic Chromosomes

    PubMed Central

    Piolot, Tristan; Tramier, Marc; Coppey, Maité; Nicolas, Jean-Claude; Marechal, Vincent

    2001-01-01

    Human herpesvirus 8 is associated with all forms of Kaposi's sarcoma, AIDS-associated body cavity-based lymphomas, and some forms of multicentric Castleman's disease. Herpesvirus 8, like other gammaherpesviruses, can establish a latent infection in which viral genomes are stably maintained as multiple episomes. The latent nuclear antigen (LANA or LNAI) may play an essential role in the stable maintenance of latent episomes, notably by interacting concomitantly with the viral genomes and the metaphase chromosomes, thus ensuring an efficient transmission of the neoduplicated episo