scholarly journals Kaposi’s sarcoma-associated herpesvirus promotes mesenchymal-to-endothelial transition by resolving the bivalent chromatin of PROX1 gene

2021 ◽  
Vol 17 (9) ◽  
pp. e1009847
Author(s):  
Yao Ding ◽  
Weikang Chen ◽  
Zhengzhou Lu ◽  
Yan Wang ◽  
Yan Yuan
Keyword(s):  
Stem Cells ◽  
Kaposi's Sarcoma ◽  
Embryonic Stem ◽  
Kaposi’S Sarcoma ◽  
Kshv Infection ◽  
Invasion And Migration ◽  
Endothelial Lineage ◽  
Kaposi's Sarcoma Associated Herpesvirus ◽  
Kaposi’S Sarcoma Associated Herpesvirus ◽  
Msc Differentiation

Increasing evidence suggests that Kaposi’s sarcoma (KS) arises from Kaposi’s sarcoma-associated herpesvirus (KSHV)-infected mesenchymal stem cells (MSCs) through mesenchymal-to-endothelial transition (MEndT). KSHV infection promotes MSC differentiation of endothelial lineage and acquisition of tumorigeneic phenotypes. To understand how KSHV induces MEndT and transforms MSCs to KS cells, we investigated the mechanism underlying KSHV-mediated MSC endothelial lineage differentiation. Like embryonic stem cells, MSC differentiation and fate determination are under epigenetic control. Prospero homeobox 1 (PROX1) is a master regulator that controls lymphatic vessel development and endothelial differentiation. We found that the PROX1 gene in MSCs harbors a distinctive bivalent epigenetic signature consisting of both active marker H3K4me3 and repressive marker H3K27me3, which poises expression of the genes, allowing timely activation upon differentiation signals or environmental stimuli. KSHV infection effectively resolves the bivalent chromatin by decreasing H3K27me3 and increasing H3K4me3 to activate the PROX1 gene. vIL-6 signaling leads to the recruitment of MLL2 and SET1 complexes to the PROX1 promoter to increase H3K4me3, and the vGPCR-VEGF-A axis is responsible for removing PRC2 from the promoter to reduce H3K27me3. Therefore, through a dual signaling process, KSHV activates PROX1 gene expression and initiates MEndT, which renders MSC tumorigenic features including angiogenesis, invasion and migration.

scholarly journals Kaposi’s Sarcoma-associated Herpesvirus Promotes Mesenchymal-to-Endothelial Transition by Resolving the Bivalent Chromatin of PROX1 Gene

2021 ◽  
Author(s):  
Yao Ding ◽  
Weikang Chen ◽  
Zhengzhou Lu ◽  
Yan Wang ◽  
Yan Yuan
Keyword(s):  
Stem Cells ◽  
Kaposi's Sarcoma ◽  
Embryonic Stem ◽  
Human Mesenchymal Stem Cells ◽  
Kaposi’S Sarcoma ◽  
Kshv Infection ◽  
Invasion And Migration ◽  
Lineage Differentiation ◽  
Kaposi's Sarcoma Associated Herpesvirus ◽  
Kaposi’S Sarcoma Associated Herpesvirus

AbstractHuman mesenchymal stem cells (MSCs) are highly susceptible to Kaposi’s sarcoma-associated herpesvirus (KSHV) infection, and the infection promotes mesenchymal-to-endothelial transition (MEndT) and acquisition of Kaposi’s sarcoma (KS)-like phenotypes. Increasing evidence suggests that KS may arise from KSHV-infected MSCs. To understand how KSHV induces MEndT and transforms MSCs to KS cells, we investigated the mechanism underlying KSHV-mediated MSC endothelial lineage differentiation. Like embryonic stem cells, MSC differentiation and fate determination are under epigenetic control. Prospero homeobox 1 (PROX1) is a master regulator that controls lymphatic vessel development and endothelial differentiation. We found that the PROX1 gene in MSCs harbors a distinctive bivalent epigenetic signature consisting of both active marker H3K4me3 and repressive marker H3K27me3, which poises expression of the genes, allowing timely activation upon differentiation signals or environmental stimuli. KSHV infection effectively resolved the bivalent chromatin by decreased H3K27me3 and increased H3K4me3 to activate the PROX1 gene. vIL-6 signaling leads to the recruitment of MLL2 and Set1 complexes to the PROX1 promoter to increase H3K4me3, and the vGPCR-VEGF-A axis is responsible for removing PRC2 from the promoter to reduce H3K27me3. Therefore, through a dual signaling process, KSHV activates PROX1 gene expression and initiates MEndT, which renders MSC tumorigenic features including angiogenesis, invasion and migration.

scholarly journals Disintegrin-like domain of glycoprotein B regulates Kaposi’s sarcoma-associated herpesvirus infection of cells

2014 ◽  
Vol 95 (8) ◽  
pp. 1770-1782 ◽  
Author(s):  
Lia R. Walker ◽  
Hosni A. M. Hussein ◽  
Shaw M. Akula
Keyword(s):  
Kaposi's Sarcoma ◽  
Kaposi’S Sarcoma ◽  
Glycoprotein B ◽  
Binding Motif ◽  
Wild Type ◽  
Infection Rates ◽  
Herpesvirus Infection ◽  
Kshv Infection ◽  
Kaposi's Sarcoma Associated Herpesvirus ◽  
Kaposi’S Sarcoma Associated Herpesvirus

Kaposi's sarcoma-associated herpesvirus (KSHV) glycoprotein B (gB) is a lytic structural protein expressed on the envelope of mature virions and on the membrane of cells supporting lytic infection. In addition to this viral glycoprotein’s interaction with integrins via its RGD (Arg-Gly-Asp) motif, KSHV gB possesses a disintegrin-like domain (DLD), which binds integrins as well. Prior to this study, there has been minimal research involving the less common integrin-binding motif, DLD, of gB as it pertains to herpesvirus infection. By using phage display peptide library screening and molecular biology techniques, the DLD of KSHV gB was shown to interact specifically with non-RGD binding α9β1 integrins. Similarly, monitoring wild-type infection confirmed α9β1:DLD interactions to be critical to successful KSHV infection of human foreskin fibroblast (HFF) cells and human dermal microvascular endothelial cells (HMVEC-d) compared with 293 cells. To further demonstrate the importance of the DLD of gB in KSHV infection, two recombinant virus constructs were generated using a bacterial artificial chromosome (BAC) system harbouring the KSHV genome (BAC36): BAC36ΔD-KSHV (lacking a functionally intact DLD of gB and containing an introduced tetracycline cassette) and BAC36.T-KSHV (containing an intact DLD sequence and an introduced tetracycline cassette). Accordingly, BAC36ΔD-KSHV presented significantly lower infection rates in HFF and HMVEC-d cells compared with the comparable infection rates achieved by wild-type BAC36-KSHV and BAC36.T-KSHV. Thus, the present report has delineated a critical role for the DLD of gB in KSHV infection, which may lead to a broader knowledge regarding the sophisticated mechanisms utilized by virus-encoded structural proteins in KSHV entry and infection.

scholarly journals Focal Adhesion Kinase Is Critical for Entry of Kaposi's Sarcoma-Associated Herpesvirus into Target Cells

2006 ◽  
Vol 80 (3) ◽  
pp. 1167-1180 ◽  
Author(s):  
Harinivas H. Krishnan ◽  
Neelam Sharma-Walia ◽  
Daniel N. Streblow ◽  
Pramod P. Naranatt ◽  
Bala Chandran
Keyword(s):  
Focal Adhesion Kinase ◽  
Focal Adhesion ◽  
Viral Entry ◽  
Kaposi's Sarcoma ◽  
Kaposi’S Sarcoma ◽  
Target Cells ◽  
Viral Dna ◽  
Kshv Infection ◽  
Kaposi's Sarcoma Associated Herpesvirus ◽  
Kaposi’S Sarcoma Associated Herpesvirus

ABSTRACT Kaposi's sarcoma-associated herpesvirus/human herpesvirus 8 (KSHV/HHV-8) interacts with cell surface α3β1 integrin early during in vitro infection of human endothelial cells and fibroblasts and activates the focal adhesion kinase (FAK) that is immediately downstream in the outside-in signaling pathway by integrins, leading to the activation of several downstream signaling molecules. In this study, using real-time DNA and reverse transcription-PCR assays to measure total internalized viral DNA, viral DNA associated with infected nuclei, and viral gene expression, we examined the stage of infection at which FAK plays the most significant role. Early during KSHV infection, FAK was phosphorylated in FAK-positive Du17 mouse embryonic fibroblasts. The absence of FAK in Du3 (FAK−/−) cells resulted in about 70% reduction in the internalization of viral DNA, suggesting that FAK plays a role in KSHV entry. Expression of FAK in Du3 (FAK−/−) cells via an adenovirus vector augmented the internalization of viral DNA. Expression of the FAK dominant-negative mutant FAK-related nonkinase (FRNK) in Du17 cells significantly reduced the entry of virus. Virus entry in Du3 cells, albeit in reduced quantity, delivery of viral DNA to the infected cell nuclei, and expression of KSHV genes suggested that in the absence of FAK, another molecule(s) may be partially compensating for FAK function. Infection of Du3 cells induced the phosphorylation of the FAK-related proline-rich tyrosine kinase (Pyk2) molecule, which has been shown to complement some of the functions of FAK. Expression of an autophosphorylation site mutant of Pyk2 in which Y402 is mutated to F (F402 Pyk2) reduced viral entry in Du3 cells, suggesting that Pyk2 facilitates viral entry moderately in the absence of FAK. These results suggest a critical role for KSHV infection-induced FAK in the internalization of viral DNA into target cells.

scholarly journals NFAT and CREB Regulate Kaposi's Sarcoma-Associated Herpesvirus-Induced Cyclooxygenase 2 (COX-2)

2010 ◽  
Vol 84 (24) ◽  
pp. 12733-12753 ◽  
Author(s):  
Neelam Sharma-Walia ◽  
Arun George Paul ◽  
Kinjan Patel ◽  
Karthic Chandran ◽  
Waseem Ahmad ◽  
...  
Keyword(s):  
Transcriptional Regulation ◽  
Protein Kinase ◽  
Kaposi's Sarcoma ◽  
Kaposi’S Sarcoma ◽  
Prostaglandin E ◽  
Intracellular Camp ◽  
Kshv Infection ◽  
Cox 2 ◽  
Kaposi's Sarcoma Associated Herpesvirus ◽  
Kaposi’S Sarcoma Associated Herpesvirus

ABSTRACT COX-2 has been implicated in Kaposi's sarcoma-associated herpesvirus (KSHV) latency and pathogenesis (A. George Paul, N. Sharma-Walia, N. Kerur, C. White, and B. Chandran, Cancer Res. 70:3697-3708, 2010; P. P. Naranatt, H. H. Krishnan, S. R. Svojanovsky, C. Bloomer, S. Mathur, and B. Chandran, Cancer Res. 64:72-84, 2004; N. Sharma-Walia, A. G. Paul, V. Bottero, S. Sadagopan, M. V. Veettil, N. Kerur, and B. Chandran, PLoS Pathog. 6:e1000777, 2010; N. Sharma-Walia, H. Raghu, S. Sadagopan, R. Sivakumar, M. V. Veettil, P. P. Naranatt, M. M. Smith, and B. Chandran, J. Virol. 80:6534-6552, 2006). However, the precise regulatory mechanisms involved in COX-2 induction during KSHV infection have never been explored. Here, we identified cis-acting elements involved in the transcriptional regulation of COX-2 upon KSHV de novo infection. Promoter analysis using human COX-2 promoter deletion and mutation reporter constructs revealed that nuclear factor of activated T cells (NFAT) and the cyclic AMP (cAMP) response element (CRE) modulate KSHV-mediated transcriptional regulation of COX-2. Along with multiple KSHV-induced signaling pathways, infection-induced prostaglandin E2 (PGE2) also augmented COX-2 transcription. Infection of endothelial cells markedly induced COX-2 expression via a cyclosporine A-sensitive, calcineurin/NFAT-dependent pathway. KSHV infection increased intracellular cAMP levels and activated protein kinase A (PKA), which phosphorylated the CRE-binding protein (CREB) at serine 133, which probably led to interaction with CRE in the COX-2 promoter, thereby enhancing COX-2 transcription. PKA selective inhibitor H-89 pretreatment strongly inhibited CREB serine 133, indicating the involvement of a cAMP-PKA-CREB-CRE loop in COX-2 transcriptional regulation. In contrast to phosphatidylinositol 3-kinase and protein kinase C, inhibition of FAK and Src effectively reduced KSHV infection-induced COX-2 transcription and protein levels. Collectively, our study indicates that mediation of COX-2 transcription upon KSHV infection is a paradigm of a complex regulatory milieu involving the interplay of multiple signal cascades and transcription factors. Intervention at each step of COX-2/PGE2 induction can be used as a potential therapeutic target to treat KSHV-associated neoplasm and control inflammatory sequels of KSHV infection.

scholarly journals Kaposi’s Sarcoma-Associated Herpesvirus, but Not Epstein-Barr Virus, Co-infection Associates With Coronavirus Disease 2019 Severity and Outcome in South African Patients

2022 ◽  
Vol 12 ◽  
Author(s):  
Melissa J. Blumenthal ◽  
Humaira Lambarey ◽  
Abeen Chetram ◽  
Catherine Riou ◽  
Robert J. Wilkinson ◽  
...  
Keyword(s):  
South Africa ◽  
South African ◽  
Kaposi's Sarcoma ◽  
Epstein Barr Virus ◽  
Kaposi’S Sarcoma ◽  
Kshv Infection ◽  
Barr Virus ◽  
Kaposi's Sarcoma Associated Herpesvirus ◽  
Epstein Barr ◽  
Kaposi’S Sarcoma Associated Herpesvirus

In South Africa, the Coronavirus Disease 2019 (COVID-19) pandemic is occurring against the backdrop of high Human Immunodeficiency Virus (HIV), tuberculosis and non-communicable disease burdens as well as prevalent herpesviruses infections such as Epstein-Barr virus (EBV) and Kaposi’s sarcoma-associated herpesvirus (KSHV). As part of an observational study of adults admitted to Groote Schuur Hospital, Cape Town, South Africa during the period June–August 2020 and assessed for Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infection, we measured KSHV serology and KSHV and EBV viral load (VL) in peripheral blood in relation to COVID-19 severity and outcome. A total of 104 patients with PCR-confirmed SARS-CoV-2 infection were included in this study. 61% were men and 39% women with a median age of 53 years (range 21–86). 29.8% (95% CI: 21.7–39.1%) of the cohort was HIV positive and 41.1% (95% CI: 31.6–51.1%) were KSHV seropositive. EBV VL was detectable in 84.4% (95% CI: 76.1–84.4%) of the cohort while KSHV DNA was detected in 20.6% (95% CI: 13.6–29.2%), with dual EBV/KSHV infection in 17.7% (95% CI: 11.1–26.2%). On enrollment, 48 [46.2% (95% CI: 36.8–55.7%)] COVID-19 patients were classified as severe on the WHO ordinal scale reflecting oxygen therapy and supportive care requirements and 30 of these patients [28.8% (95% CI: 20.8–38.0%)] later died. In COVID-19 patients, detectable KSHV VL was associated with death after adjusting for age, sex, HIV status and detectable EBV VL [p = 0.036, adjusted OR = 3.17 (95% CI: 1.08–9.32)]. Furthermore, in HIV negative COVID-19 patients, there was a trend indicating that KSHV VL may be related to COVID-19 disease severity [p = 0.054, unstandardized co-efficient 0.86 (95% CI: –0.015–1.74)] in addition to death [p = 0.008, adjusted OR = 7.34 (95% CI: 1.69–31.49)]. While the design of our study cannot distinguish if disease synergy exists between COVID-19 and KSHV nor if either viral infection is indeed fueling the other, these data point to a potential contribution of KSHV infection to COVID-19 outcome, or SARS-CoV-2 infection to KSHV reactivation, particularly in the South African context of high disease burden, that warrants further investigation.

scholarly journals Human Immunodeficiency Virus-Associated Exosomes Promote Kaposi’s Sarcoma-Associated Herpesvirus Infection via the Epidermal Growth Factor Receptor

2020 ◽  
Vol 94 (9) ◽  
Author(s):  
Lechuang Chen ◽  
Zhimin Feng ◽  
Guoxiang Yuan ◽  
Corey C. Emerson ◽  
Phoebe L. Stewart ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Kaposi's Sarcoma ◽  
Kaposi’S Sarcoma ◽  
Kshv Infection ◽  
Oral Epithelial Cells ◽  
Tar Rna ◽  
Kaposi's Sarcoma Associated Herpesvirus ◽  
Kaposi’S Sarcoma Associated Herpesvirus ◽  
Oral Epithelial ◽  
Hiv Aids

ABSTRACT Kaposi’s sarcoma-associated herpesvirus (KSHV) is the causal agent for Kaposi’s sarcoma (KS), the most common malignancy in people living with human immunodeficiency virus (HIV)/AIDS. The oral cavity is a major route for KSHV infection and transmission. However, how KSHV breaches the oral epithelial barrier for spreading to the body is not clear. Here, we show that exosomes purified from either the saliva of HIV-positive individuals or the culture supernatants of HIV-1-infected T-cell lines promote KSHV infectivity in immortalized and primary human oral epithelial cells. HIV-associated saliva exosomes contain the HIV trans-activation response element (TAR), Tat, and Nef RNAs but do not express Tat and Nef proteins. The TAR RNA in HIV-associated exosomes contributes to enhancing KSHV infectivity through the epidermal growth factor receptor (EGFR). An inhibitory aptamer against TAR RNA reduces KSHV infection facilitated by the synthetic TAR RNA in oral epithelial cells. Cetuximab, a monoclonal neutralizing antibody against EGFR, blocks HIV-associated exosome-enhanced KSHV infection. Our findings reveal that saliva containing HIV-associated exosomes is a risk factor for the enhancement of KSHV infection and that the inhibition of EGFR serves as a novel strategy for preventing KSHV infection and transmission in the oral cavity. IMPORTANCE Kaposi’s sarcoma-associated herpesvirus (KSHV) is the causal agent for Kaposi’s sarcoma (KS), the most common malignancy in HIV/AIDS patients. Oral transmission through saliva is considered the most common route for spreading the virus among HIV/AIDS patients. However, the role of HIV-specific components in the cotransfection of KSHV is unclear. We demonstrate that exosomes purified from the saliva of HIV-positive patients and secreted by HIV-infected T-cell lines promote KSHV infectivity in immortalized and primary oral epithelial cells. HIV-associated exosomes promote KSHV infection, which depends on HIV trans-activation response element (TAR) RNA and EGFR of oral epithelial cells, which can be targeted for reducing KSHV infection. These results reveal that HIV-associated exosomes are a risk factor for KSHV infection in the HIV-infected population.

scholarly journals Identifying cellular genes crucial for the reactivation of Kaposi's sarcoma-associated herpesvirus latency

2006 ◽  
Vol 87 (3) ◽  
pp. 519-529 ◽  
Author(s):  
Benjaman A. Bryan ◽  
Ossie F. Dyson ◽  
Shaw M. Akula
Keyword(s):  
Cell Cycle ◽  
Flow Cytometry ◽  
Kaposi's Sarcoma ◽  
Kaposi’S Sarcoma ◽  
S Phase ◽  
Lytic Cycle ◽  
Kshv Infection ◽  
Cellular Genes ◽  
Kaposi's Sarcoma Associated Herpesvirus ◽  
Kaposi’S Sarcoma Associated Herpesvirus

Kaposi's sarcoma-associated herpesvirus (KSHV) is the latest addition to the long list of human herpesviruses. Reactivation of latent herpesvirus infections is still a mystery. It was demonstrated recently that the phorbol ester TPA was efficient in inducing a reactivation of KSHV infection in the S phase of the cell cycle. In the present study, flow cytometry-sorted, TPA-induced, KSHV-infected haematopoietic cells (BCBL-1) were used to analyse the expression profiles of cancer-related cellular genes in the S phase of the cell cycle compared with the G0/1 phase by using microarrays. Overall, the S phase of the cell cycle seems to provide KSHV with an apt environment for a productive lytic cycle of infection. The apt conditions include cellular signalling that promotes survivability, DNA replication and lipid metabolism, while blocking cell-cycle progression to M phase. Some of the important genes that were overexpressed during the S phase of the cell cycle compared with the G0/1 phase of TPA-induced BCBL-1 cells are v-myb myeloblastosis (MYBL2), protein kinase-membrane associated tyrosine/threonine 1 (PKMYT1), ribonucleotide reductase M1 polypeptide (RRM1) and peroxisome proliferator-activated receptors delta (PPARD). Inhibition of PKMYT1 expression by the use of specific short interfering RNAs significantly lowered the TPA-induced KSHV lytic cycle of infection. The significance of these and other genes in the reactivation of KSHV is discussed in the following report. Taken together, a flow cytometry–microarray-based method to study the cellular conditions critical for the reactivation of KSHV infection is reported here for the first time.

scholarly journals Efficient Infection by a Recombinant Kaposi's Sarcoma-Associated Herpesvirus Cloned in a Bacterial Artificial Chromosome: Application for Genetic Analysis

2002 ◽  
Vol 76 (12) ◽  
pp. 6185-6196 ◽  
Author(s):  
Fu-Chun Zhou ◽  
Yan-Jin Zhang ◽  
Jian-Hong Deng ◽  
Xin-Ping Wang ◽  
Hong-Yi Pan ◽  
...  
Keyword(s):  
Genetic Analysis ◽  
Cell Lines ◽  
Kaposi's Sarcoma ◽  
Kaposi’S Sarcoma ◽  
Artificial Chromosome ◽  
Lytic Replication ◽  
Kshv Infection ◽  
293 Cells ◽  
Kaposi's Sarcoma Associated Herpesvirus ◽  
Kaposi’S Sarcoma Associated Herpesvirus

ABSTRACT Kaposi's sarcoma-associated herpesvirus (KSHV) is etiologically associated with Kaposi's sarcoma and several other malignancies. The lack of an efficient infection system has impeded the understanding of KSHV-related pathogenesis. A genetic approach was used to isolate infectious KSHV. Recombinant bacteria artificial chromosome (BAC) KSHV containing hygromycin resistance and green fluorescent protein (GFP) markers was generated by homologous recombination in KSHV-infected BCBL-1 cells. Recombinant KSHV genomes from cell clones that were resistant to hygromycin, expressed GFP, and produced infectious virions after induction with tetradecanoyl phorbol acetate (TPA) were rescued in Escherichia coli and reconstituted in 293 cells. Several 293 cell lines resulting from infection with recombinant virions induced from a full-length recombinant KSHV genome, named BAC36, were obtained. BAC36 virions established stable latent infection in 293 cells, harboring 1 to 2 copies of viral genome per cell and expressing viral latent proteins, with ≈0.5% of cells undergoing spontaneous lytic replication, which is reminiscent of KSHV infection in Kaposi's sarcoma tumors. TPA treatment induced BAC36-infected 293 cell lines into productive lytic replication, expressing lytic proteins and producing virions that efficiently infected normal 293 cells with a ≈50% primary infection rate. BAC36 virions were also infectious to HeLa and E6E7-immortalized human endothelial cells. Since BAC36 can be efficiently shuttled between bacteria and mammalian cells, it is useful for KSHV genetic analysis. The feasibility of the system was illustrated through the generation of a KSHV mutant with the vIRF gene deleted. This cellular model is useful for the investigation of KSHV infection and pathogenesis.

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