RESUMEN

Kaposi's sarcoma-associated herpesvirus (KSHV) is the causative agent for primary effusion lymphoma (PEL), multicentric Castleman's disease (MCD) and Kaposi's sarcoma (KS). KSHV is one of the oncoviruses that contribute to 1.5 million new infection-related cancer cases annually. Currently, there are no targeted therapies for KSHV-associated diseases. Through the development of a medium-throughput phenotype-based ELISA screening platform based on KSHV ORF57 protein detection, we screened the Medicines for Malaria Venture (MMV) Pandemic Response Box for non-cytotoxic inhibitors of KSHV lytic replication. MMV1645152 was identified as a promising inhibitor of KSHV lytic replication, suppressing KSHV immediate-early and late lytic gene expression and blocking the production of infectious KSHV virion particles at non-cytotoxic concentrations in cell line models of KSHV infection with or without EBV coinfection. MMV1645152 is a promising hit compound for the development of future therapeutic agents against KSHV-associated malignancies.

Asunto(s)

Antivirales , Descubrimiento de Drogas , Herpesvirus Humano 8 , Replicación Viral , Herpesvirus Humano 8/efectos de los fármacos , Herpesvirus Humano 8/fisiología , Herpesvirus Humano 8/genética , Humanos , Replicación Viral/efectos de los fármacos , Antivirales/farmacología , Línea Celular , Evaluación Preclínica de Medicamentos , Bibliotecas de Moléculas Pequeñas/farmacología , Sarcoma de Kaposi/virología , Sarcoma de Kaposi/tratamiento farmacológico

RESUMEN

Kaposi's sarcoma-associated herpesvirus (KSHV) establishes persistent infection in the host by encoding a vast network of proteins that aid immune evasion. One of these targeted innate immunity pathways is the cGAS-STING pathway, which inhibits the reactivation of KSHV from latency. Previously, we identified multiple cGAS/STING inhibitors encoded by KSHV, suggesting that the counteractions of this pathway by viral proteins are critical for maintaining a successful KSHV life cycle. However, the detailed mechanisms of how these viral proteins block innate immunity and facilitate KSHV lytic replication remain largely unknown. In this study, we report that ORF48, a previously identified negative regulator of the cGAS/STING pathway, is required for optimal KSHV lytic replication. We used both siRNA and deletion-based systems to evaluate the importance of intact ORF48 in the KSHV lytic cycle. In both systems, loss of ORF48 resulted in defects in lytic gene transcription, lytic protein expression, viral genome replication and infectious virion production. ORF48 genome deletion caused more robust and global repression of the KSHV transcriptome, possibly due to the disruption of RTA promoter activity. Mechanistically, overexpressed ORF48 was found to colocalize and interact with endogenous STING in HEK293 cells. Endogenous ORF48 and STING interactions were also detected in reactivated iSLK.219 cells. Compared with the control cell line, HUVEC cells stably expressing ORF48 exhibited repressed STING-dependent innate immune signaling upon ISD or diABZI treatment. However, the loss of ORF48 in our iSLK-based lytic system failed to induce IFNß production, suggesting a redundant role of ORF48 on STING signaling during the KSHV lytic phase. Thus, ORF48 is required for optimal KSHV lytic replication through additional mechanisms that need to be further explored.

Asunto(s)

Herpesvirus Humano 8 , Proteínas Virales , Replicación Viral , Herpesvirus Humano 8/fisiología , Humanos , Replicación Viral/fisiología , Proteínas Virales/metabolismo , Proteínas Virales/genética , Inmunidad Innata , Células HEK293 , Sarcoma de Kaposi/virología , Sarcoma de Kaposi/metabolismo , Regulación Viral de la Expresión Génica , Latencia del Virus/fisiología , Infecciones por Herpesviridae/metabolismo , Infecciones por Herpesviridae/virología

RESUMEN

Kaposi sarcoma (KS) is a neoplasm of vascular origin that promotes angiogenesis and the growth of endothelial cells triggered by the Kaposi Sarcoma-associated Herpes Virus (KSHV). When associated with HIV, KSHV becomes more aggressive and rapidly evolves. The HIV-1 TAT protein can be essential in developing AIDS-associated KS by promoting angiogenesis and increasing KSHV replication. Therefore, we evaluated the genetic profile of the first exon of tat gene among groups of people living with HIV (PLHIV) with (case group, n = 36) or without KS, this later with (positive control group, n = 46) and without KSHV infection (negative control group, n = 24); all individuals under antiretroviral therapy. The genetic diversity, the DN/DS ratio, and the genetic entropy of the first exon of tat were higher in the case group, followed by the positive control group, which was higher than the negative control group. The number of tat codons under positive selection was seven in the case group, six in the positive control group, and one in the negative control group. The prevalence of HIV viral loads below the detection limit was equal in the case and positive control groups, which were lower than in the negative control group. The mean CD4+ T cell counts were higher in the negative control group, followed by the positive control group, and followed by the case group. These results emphasize the negative influence of KSHV in antiretroviral treatment, as well as the HIV-specific TAT profile among PLHIV who developed KS.

Asunto(s)

Coinfección , Infecciones por VIH , Herpesvirus Humano 8 , Sarcoma de Kaposi , Productos del Gen tat del Virus de la Inmunodeficiencia Humana , Humanos , Sarcoma de Kaposi/virología , Infecciones por VIH/complicaciones , Infecciones por VIH/tratamiento farmacológico , Infecciones por VIH/virología , Masculino , Herpesvirus Humano 8/genética , Femenino , Adulto , Persona de Mediana Edad , Productos del Gen tat del Virus de la Inmunodeficiencia Humana/genética , Coinfección/virología , Coinfección/tratamiento farmacológico , VIH-1/genética , VIH-1/efectos de los fármacos , Variación Genética , Carga Viral , Antirretrovirales/uso terapéutico , Recuento de Linfocito CD4

RESUMEN

Kaposi's sarcoma (KS) is an angio-proliferative disease with a viral etiology and a multifactorial pathogenesis that results from immune dysfunction. In patients affected by latent viral infections such as herpesviruses, SARS-CoV-2 infection may result in lytic cycle reactivation in host cells. A robust immune system response is crucial for eliminating pathogens and resolving both latent and non-latent viral infections. We report a case series of KS characterized by tumor progression after SARS-CoV-2 infection. We performed a systematic literature review of the PubMed/MEDLINE and EMBASE databases. The keyword terms included "SARS-CoV-2," "HHV-8," "Kaposi's sarcoma," "IL-6," and "COVID-19." English language restriction was applied. Items not covered by our study were excluded. KS is a complex disease linked to an impaired immune system. Conditions that result in temporary or permanent immunodeficiency can trigger viral reactivation or exacerbate an existing disease. It is feasible that the increase in cytokine levels in COVID-19 patients, coupled with lymphocyte downregulation and treatment that induces herpesvirus lytic reactivation, may contribute to the progression of KS after SARS-CoV-2 infection. These observations suggest that patients with KS should be clinically monitored both during and after SARS-CoV-2 infection. Nevertheless, prospective data should be collected to validate this hypothesis and enhance our understanding of the mechanisms implicated in the onset or progression of KS.

Asunto(s)

COVID-19 , Herpesvirus Humano 8 , SARS-CoV-2 , Sarcoma de Kaposi , Humanos , COVID-19/inmunología , COVID-19/complicaciones , COVID-19/virología , Sarcoma de Kaposi/virología , Masculino , Persona de Mediana Edad , Femenino , Anciano , Activación Viral

Asunto(s)

Enfermedad de Castleman , Herpesvirus Humano 8 , Sarcoma de Kaposi , Humanos , Enfermedad de Castleman/patología , Sarcoma de Kaposi/patología , Sarcoma de Kaposi/virología , Masculino , Ganglios Linfáticos/patología , Persona de Mediana Edad , Infecciones por Herpesviridae/complicaciones , Infecciones por Herpesviridae/patología , Femenino

RESUMEN

Human herpesviruses (HHVs) cause a wide variety of central nervous system (CNS) infections including meningitis and encephalitis. While HHV-8 is not typically associated with neurological diseases, several studies have indicated a relationship, such as secondary central nervous system (CNS) metastases and a few isolated cases of HHV-8 encephalitis in acquired immunodeficiency syndrome (HIV). However, it has not been previously linked to encephalitis in solid organ transplantation (SOT). This case presents the first-ever instance of HHV-8 encephalitis in a SOT recipient. Our case highlights the association of HHV-8-related diseases, such as post-transplant Kaposi's Sarcoma (KS), with encephalitis. The patient was diagnosed with KS before developing neurological symptoms and received a prompt clinical response through intravenous foscarnet and ganciclovir treatment for 14 days. It is important to note that HHV-8 is a rare cause of encephalitis, and diagnosis requires a high index of suspicion in the appropriate clinical context, allowing for the use of antiviral therapy. This case also underscores the importance of considering the possibility of HHV-8-related diseases in SOT recipients, as they are at risk of developing such infections.

Asunto(s)

Antivirales , Encefalitis Viral , Ganciclovir , Infecciones por Herpesviridae , Herpesvirus Humano 8 , Sarcoma de Kaposi , Humanos , Herpesvirus Humano 8/aislamiento & purificación , Sarcoma de Kaposi/virología , Antivirales/uso terapéutico , Masculino , Infecciones por Herpesviridae/virología , Infecciones por Herpesviridae/complicaciones , Infecciones por Herpesviridae/diagnóstico , Encefalitis Viral/virología , Encefalitis Viral/diagnóstico , Encefalitis Viral/tratamiento farmacológico , Ganciclovir/uso terapéutico , Foscarnet/uso terapéutico , Persona de Mediana Edad , Receptores de Trasplantes , Trasplante de Órganos/efectos adversos

RESUMEN

Kaposi's sarcoma-associated herpesvirus (KSHV) is an oncogenic herpesvirus that is linked directly to the development of Kaposi's sarcoma. KSHV establishes a latent infection in B cells, which can be reactivated to initiate lytic replication, producing infectious virions. Using pharmacological and genetic silencing approaches, we showed that the voltage-gated K+ channel Kv1.3 in B cells enhanced KSHV lytic replication. The KSHV replication and transcription activator (RTA) protein increased the abundance of Kv1.3 and led to enhanced K+ channel activity and hyperpolarization of the B cell membrane. Enhanced Kv1.3 activity promoted intracellular Ca2+ influx, leading to the Ca2+-driven nuclear localization of KSHV RTA and host nuclear factor of activated T cells (NFAT) proteins and subsequently increased the expression of NFAT1 target genes. KSHV lytic replication and infectious virion production were inhibited by Kv1.3 blockers or silencing. These findings highlight Kv1.3 as a druggable host factor that is key to the successful completion of KSHV lytic replication.

Asunto(s)

Herpesvirus Humano 8 , Canal de Potasio Kv1.3 , Factores de Transcripción NFATC , Replicación Viral , Herpesvirus Humano 8/fisiología , Herpesvirus Humano 8/genética , Herpesvirus Humano 8/metabolismo , Humanos , Canal de Potasio Kv1.3/metabolismo , Canal de Potasio Kv1.3/genética , Canal de Potasio Kv1.3/antagonistas & inhibidores , Factores de Transcripción NFATC/metabolismo , Factores de Transcripción NFATC/genética , Proteínas Inmediatas-Precoces/metabolismo , Proteínas Inmediatas-Precoces/genética , Transactivadores/metabolismo , Transactivadores/genética , Linfocitos B/virología , Linfocitos B/metabolismo , Calcio/metabolismo , Sarcoma de Kaposi/virología , Sarcoma de Kaposi/metabolismo , Sarcoma de Kaposi/genética

RESUMEN

Recently published near full-length KSHV genomes from a Cameroon Kaposi sarcoma case-control study showed strong evidence of viral recombination and mixed infections, but no sequence variations associated with disease. Using the same methodology, an additional 102 KSHV genomes from 76 individuals with KSHV-associated diseases have been sequenced. Diagnoses comprise all KSHV-associated diseases (KAD): Kaposi sarcoma (KS), primary effusion lymphoma (PEL), KSHV-associated large cell lymphoma (KSHV-LCL), a type of multicentric Castleman disease (KSHV-MCD), and KSHV inflammatory cytokine syndrome (KICS). Participants originated from 22 different countries, providing the opportunity to obtain new near full-length sequences of a wide diversity of KSHV genomes. These include near full-length sequence of genomes with KSHV K1 subtypes A, B, C, and F as well as subtype E, for which no full sequence was previously available. High levels of recombination were observed. Fourteen individuals (18%) showed evidence of infection with multiple KSHV variants (from two to four unique genomes). Twenty-six comparisons of sequences, obtained from various sampling sites including PBMC, tissue biopsies, oral fluids, and effusions in the same participants, identified near complete genome conservation between different biological compartments. Polymorphisms were identified in coding and non-coding regions, including indels in the K3 and K15 genes and sequence inversions here reported for the first time. One such polymorphism in KSHV ORF46, specific to the KSHV K1 subtype E2, encoded a mutation in the leucine loop extension of the uracil DNA glycosylase that results in alteration of biochemical functions of this protein. This confirms that KSHV sequence variations can have functional consequences warranting further investigation. This study represents the largest and most diverse analysis of KSHV genome sequences to date among individuals with KAD and provides important new information on global KSHV genomics.

Asunto(s)

Genoma Viral , Herpesvirus Humano 8 , Sarcoma de Kaposi , Humanos , Herpesvirus Humano 8/genética , Sarcoma de Kaposi/virología , Sarcoma de Kaposi/genética , Masculino , Femenino , Persona de Mediana Edad , Adulto , Polimorfismo Genético , Anciano , Infecciones por Herpesviridae/genética , Infecciones por Herpesviridae/virología , Etnicidad/genética , Enfermedad de Castleman/virología , Enfermedad de Castleman/genética , Filogenia

RESUMEN

SUMMARYWithin weeks of the first report of acquired immunodeficiency syndrome (AIDS) in 1981, it was observed that these patients often had Kaposi sarcoma (KS), a hitherto rarely seen skin tumor in the USA. It soon became apparent that AIDS was also associated with an increased incidence of high-grade lymphomas caused by Epstein-Barr virus (EBV). The association of AIDS with KS remained a mystery for more than a decade until Kaposi sarcoma-associated herpesvirus (KSHV) was discovered and found to be the cause of KS. KSHV was subsequently found to cause several other diseases associated with AIDS and human immunodeficiency virus (HIV) infection. People living with HIV/AIDS continue to have an increased incidence of certain cancers, and many of these cancers are caused by EBV and/or KSHV. In this review, we discuss the epidemiology, virology, pathogenesis, clinical manifestations, and treatment of cancers caused by EBV and KSHV in persons living with HIV.

Asunto(s)

Infecciones por Virus de Epstein-Barr , Infecciones por VIH , Herpesvirus Humano 4 , Herpesvirus Humano 8 , Trastornos Linfoproliferativos , Humanos , Herpesvirus Humano 8/patogenicidad , Infecciones por Virus de Epstein-Barr/complicaciones , Infecciones por Virus de Epstein-Barr/epidemiología , Infecciones por Virus de Epstein-Barr/virología , Infecciones por VIH/complicaciones , Infecciones por VIH/epidemiología , Infecciones por VIH/virología , Trastornos Linfoproliferativos/virología , Trastornos Linfoproliferativos/epidemiología , Sarcoma de Kaposi/epidemiología , Sarcoma de Kaposi/virología , Neoplasias/virología , Neoplasias/epidemiología , Neoplasias/complicaciones

RESUMEN

Kaposi's sarcoma (KS) is a cancer affecting skin and internal organs for which the Kaposi's sarcoma associated herpesvirus (KSHV) is a necessary cause. Previous work has pursued KS diagnosis by quantifying KSHV DNA in skin biopsies using a point-of-care (POC) device which performs quantitative loop-mediated isothermal amplification (LAMP). These previous studies revealed that extracting DNA from patient biopsies was the rate limiting step in an otherwise rapid process. In this study, a simplified, POC-compatible alkaline DNA extraction, ColdSHOT, was optimized for 0.75 mm human skin punch biopsies. The optimized ColdSHOT extraction consistently produced 40,000+ copies of DNA per 5 µl reaction from 3 mg samples-a yield comparable to standard spin column extractions-within 1 h without significant equipment. The DNA yield was estimated sufficient for KSHV detection from KS-positive patient biopsies, and the LAMP assay was not affected by non-target tissue in the unpurified samples. Furthermore, the yields achieved via ColdSHOT were robust to sample storage in phosphate-buffered saline (PBS) or Tris-EDTA (TE) buffer prior to DNA extraction, and the DNA sample was stable after extraction. The results presented in this study indicate that the ColdSHOT DNA extraction could be implemented to simplify and accelerate the LAMP-based diagnosis of Kaposi's sarcoma using submillimeter biopsy samples.

Asunto(s)

ADN Viral , Herpesvirus Humano 8 , Técnicas de Amplificación de Ácido Nucleico , Sarcoma de Kaposi , Piel , Humanos , ADN Viral/genética , ADN Viral/aislamiento & purificación , Herpesvirus Humano 8/aislamiento & purificación , Herpesvirus Humano 8/genética , Biopsia/métodos , Piel/virología , Piel/patología , Sarcoma de Kaposi/diagnóstico , Sarcoma de Kaposi/virología , Sarcoma de Kaposi/patología , Sarcoma de Kaposi/genética , Técnicas de Amplificación de Ácido Nucleico/métodos , Sistemas de Atención de Punto , Técnicas de Diagnóstico Molecular/métodos

RESUMEN

Kaposi's sarcoma-associated herpesvirus is the etiologic agent of Kaposi's sarcoma and two B-cell malignancies. Recent advancements in sequencing technologies have led to high resolution transcriptomes for several human herpesviruses that densely encode genes on both strands. However, for KSHV progress remained limited due to the overall low percentage of KSHV transcripts, even during lytic replication. To address this challenge, we have developed a target enrichment method to increase the KSHV-specific reads for both short- and long-read sequencing platforms. Furthermore, we combined this approach with the Transcriptome Resolution through Integration of Multi-platform Data (TRIMD) pipeline developed previously to annotate transcript structures. TRIMD first builds a scaffold based on long-read sequencing and validates each transcript feature with supporting evidence from Illumina RNA-Seq and deepCAGE sequencing data. Our stringent innovative approach identified 994 unique KSHV transcripts, thus providing the first high-density KSHV lytic transcriptome. We describe a plethora of novel coding and non-coding KSHV transcript isoforms with alternative untranslated regions, splice junctions and open-reading frames, thus providing deeper insights on gene expression regulation of KSHV. Interestingly, as described for Epstein-Barr virus, we identified transcription start sites that augment long-range transcription and may increase the number of latency-associated genes potentially expressed in KS tumors.

Asunto(s)

Empalme Alternativo , Herpesvirus Humano 8 , Transcriptoma , Herpesvirus Humano 8/genética , Humanos , Transcriptoma/genética , Transcripción Genética , Regulación Viral de la Expresión Génica , Sistemas de Lectura Abierta/genética , Secuenciación de Nucleótidos de Alto Rendimiento , Sarcoma de Kaposi/virología , Sarcoma de Kaposi/genética , ARN Viral/genética , ARN Viral/metabolismo

RESUMEN

During viral infection, the innate immune system utilizes a variety of specific intracellular sensors to detect virus-derived nucleic acids and activate a series of cellular signaling cascades that produce type I IFNs and proinflammatory cytokines and chemokines. Kaposi's sarcoma-associated herpesvirus (KSHV) is an oncogenic double-stranded DNA virus that has been associated with a variety of human malignancies, including Kaposi's sarcoma, primary effusion lymphoma, and multicentric Castleman disease. Infection with KSHV activates various DNA sensors, including cGAS, STING, IFI16, and DExD/H-box helicases. Activation of these DNA sensors induces the innate immune response to antagonize the virus. To counteract this, KSHV has developed countless strategies to evade or inhibit DNA sensing and facilitate its own infection. This review summarizes the major DNA-triggered sensing signaling pathways and details the current knowledge of DNA-sensing mechanisms involved in KSHV infection, as well as how KSHV evades antiviral signaling pathways to successfully establish latent infection and undergo lytic reactivation.

Asunto(s)

ADN Viral , Herpesvirus Humano 8 , Inmunidad Innata , Transducción de Señal , Herpesvirus Humano 8/genética , Herpesvirus Humano 8/fisiología , Humanos , ADN Viral/metabolismo , Infecciones por Herpesviridae/virología , Infecciones por Herpesviridae/metabolismo , Sarcoma de Kaposi/virología , Nucleotidiltransferasas/metabolismo , Interacciones Huésped-Patógeno , Animales , Proteínas de la Membrana/metabolismo , Proteínas Nucleares , Fosfoproteínas

RESUMEN

Kaposi's sarcoma (KS) may derive from Kaposi's sarcoma herpesvirus (KSHV)-infected human mesenchymal stem cells (hMSCs) that migrate to sites characterized by inflammation and angiogenesis, promoting the initiation of KS. By analyzing the RNA sequences of KSHV-infected primary hMSCs, we have identified specific cell subpopulations, mechanisms, and conditions involved in the initial stages of KSHV-induced transformation and reprogramming of hMSCs into KS progenitor cells. Under proangiogenic environmental conditions, KSHV can reprogram hMSCs to exhibit gene expression profiles more similar to KS tumors, activating cell cycle progression, cytokine signaling pathways, endothelial differentiation, and upregulating KSHV oncogenes indicating the involvement of KSHV infection in inducing the mesenchymal-to-endothelial (MEndT) transition of hMSCs. This finding underscores the significance of this condition in facilitating KSHV-induced proliferation and reprogramming of hMSCs towards MEndT and closer to KS gene expression profiles, providing further evidence of these cell subpopulations as precursors of KS cells that thrive in a proangiogenic environment.

Asunto(s)

Herpesvirus Humano 8 , Células Madre Mesenquimatosas , Sarcoma de Kaposi , Humanos , Herpesvirus Humano 8/fisiología , Herpesvirus Humano 8/genética , Sarcoma de Kaposi/virología , Células Madre Mesenquimatosas/virología , Diferenciación Celular , Células Cultivadas , Perfilación de la Expresión Génica , Proliferación Celular

RESUMEN

TRIM32 is often aberrantly expressed in many types of cancers. Kaposi's sarcoma-associated herpesvirus (KSHV) is linked with several human malignancies, including Kaposi's sarcoma and primary effusion lymphomas (PELs). Increasing evidence has demonstrated the crucial role of KSHV lytic replication in viral tumorigenesis. However, the role of TRIM32 in herpesvirus lytic replication remains unclear. Here, we reveal that the expression of TRIM32 is upregulated by KSHV in latency, and reactivation of KSHV lytic replication leads to the inhibition of TRIM32 in PEL cells. Strikingly, RTA, the master regulator of lytic replication, interacts with TRIM32 and dramatically promotes TRIM32 for degradation via the proteasome systems. Inhibition of TRIM32 induces cell apoptosis and in turn inhibits the proliferation and colony formation of KSHV-infected PEL cells and facilitates the reactivation of KSHV lytic replication and virion production. Thus, our data imply that the degradation of TRIM32 is vital for the lytic activation of KSHV and is a potential therapeutic target for KSHV-associated cancers. IMPORTANCE: TRIM32 is associated with many cancers and viral infections; however, the role of TRIM32 in viral oncogenesis remains largely unknown. In this study, we found that the expression of TRIM32 is elevated by Kaposi's sarcoma-associated herpesvirus (KSHV) in latency, and RTA (the master regulator of lytic replication) induces TRIM32 for proteasome degradation upon viral lytic reactivation. This finding provides a potential therapeutic target for KSHV-associated cancers.

Asunto(s)

Herpesvirus Humano 8 , Proteínas Inmediatas-Precoces , Proteolisis , Transactivadores , Factores de Transcripción , Proteínas de Motivos Tripartitos , Ubiquitina-Proteína Ligasas , Activación Viral , Replicación Viral , Humanos , Apoptosis , Línea Celular , Herpesvirus Humano 8/crecimiento & desarrollo , Herpesvirus Humano 8/metabolismo , Herpesvirus Humano 8/patogenicidad , Herpesvirus Humano 8/fisiología , Proteínas Inmediatas-Precoces/metabolismo , Proteínas Inmediatas-Precoces/genética , Linfoma de Efusión Primaria/virología , Linfoma de Efusión Primaria/metabolismo , Complejo de la Endopetidasa Proteasomal/metabolismo , Sarcoma de Kaposi/virología , Sarcoma de Kaposi/metabolismo , Transactivadores/metabolismo , Transactivadores/genética , Factores de Transcripción/metabolismo , Factores de Transcripción/genética , Proteínas de Motivos Tripartitos/metabolismo , Proteínas de Motivos Tripartitos/genética , Ubiquitina-Proteína Ligasas/metabolismo , Ubiquitina-Proteína Ligasas/genética , Latencia del Virus

RESUMEN

Kaposi sarcoma-associated herpesvirus (KSHV), also known as human herpesvirus-8, is the causal agent of Kaposi sarcoma, a cancer that appears as tumors on the skin or mucosal surfaces, as well as primary effusion lymphoma and KSHV-associated multicentric Castleman disease, which are B-cell lymphoproliferative disorders. Effective prophylactic and therapeutic strategies against KSHV infection and its associated diseases are needed. To develop these strategies, it is crucial to identify and target viral glycoproteins involved in KSHV infection of host cells. Multiple KSHV glycoproteins expressed on the viral envelope are thought to play a pivotal role in viral infection, but the infection mechanisms involving these glycoproteins remain largely unknown. We investigated the role of two KSHV envelope glycoproteins, KSHV complement control protein (KCP) and K8.1, in viral infection in various cell types in vitro and in vivo. Using our newly generated anti-KCP antibodies, previously characterized anti-K8.1 antibodies, and recombinant mutant KSHV viruses lacking KCP, K8.1, or both, we demonstrated the presence of KCP and K8.1 on the surface of both virions and KSHV-infected cells. We showed that KSHV lacking KCP and/or K8.1 remained infectious in KSHV-susceptible cell lines, including epithelial, endothelial, and fibroblast, when compared to wild-type recombinant KSHV. We also provide the first evidence that KSHV lacking K8.1 or both KCP and K8.1 can infect human B cells in vivo in a humanized mouse model. Thus, these results suggest that neither KCP nor K8.1 is required for KSHV infection of various host cell types and that these glycoproteins do not determine KSHV cell tropism. IMPORTANCE: Kaposi sarcoma-associated herpesvirus (KSHV) is an oncogenic human gamma-herpesvirus associated with the endothelial malignancy Kaposi sarcoma and the lymphoproliferative disorders primary effusion lymphoma and multicentric Castleman disease. Determining how KSHV glycoproteins such as complement control protein (KCP) and K8.1 contribute to the establishment, persistence, and transmission of viral infection will be key for developing effective anti-viral vaccines and therapies to prevent and treat KSHV infection and KSHV-associated diseases. Using newly generated anti-KCP antibodies, previously characterized anti-K8.1 antibodies, and recombinant mutant KSHV viruses lacking KCP and/or K8.1, we show that KCP and K8.1 can be found on the surface of both virions and KSHV-infected cells. Furthermore, we show that KSHV lacking KCP and/or K8.1 remains infectious to diverse cell types susceptible to KSHV in vitro and to human B cells in vivo in a humanized mouse model, thus providing evidence that these viral glycoproteins are not required for KSHV infection.

Asunto(s)

Herpesvirus Humano 8 , Sarcoma de Kaposi , Proteínas del Envoltorio Viral , Proteínas Virales , Herpesvirus Humano 8/genética , Herpesvirus Humano 8/fisiología , Humanos , Animales , Ratones , Proteínas Virales/metabolismo , Proteínas Virales/genética , Sarcoma de Kaposi/virología , Proteínas del Envoltorio Viral/metabolismo , Proteínas del Envoltorio Viral/genética , Línea Celular , Enfermedad de Castleman/virología , Enfermedad de Castleman/metabolismo , Infecciones por Herpesviridae/virología , Infecciones por Herpesviridae/metabolismo , Células HEK293 , Células Endoteliales/virología

RESUMEN

Kaposi sarcoma (KS) is the most common cancer in persons living with HIV. It is caused by KS-associated herpesvirus (KSHV). There exists no animal model for KS. Pronuclear injection of the 170,000-bp viral genome induces early-onset, aggressive angiosarcoma in transgenic mice. The tumors are histopathologically indistinguishable from human KS. As in human KS, all tumor cells express the viral latency-associated nuclear antigen (LANA). The tumors transcribe most viral genes, whereas endothelial cells in other organs only transcribe the viral latent genes. The tumor cells are of endothelial lineage and exhibit the same molecular pattern of pathway activation as KS, namely phosphatidylinositol 3-kinase (PI3K)/Akt/mTOR, interleukin-10 (IL-10), and vascular endothelial growth factor (VEGF). The KSHV-induced tumors are more aggressive than Ha-ras-induced angiosarcomas. Overall survival is increased by prophylactic ganciclovir. Thus, whole-virus KSHV-transgenic mice represent an accurate model for KS and open the door for the genetic dissection of KS pathogenesis and evaluation of therapies, including vaccines.

Asunto(s)

Modelos Animales de Enfermedad , Hemangiosarcoma , Herpesvirus Humano 8 , Ratones Transgénicos , Sarcoma de Kaposi , Animales , Herpesvirus Humano 8/genética , Herpesvirus Humano 8/patogenicidad , Ratones , Hemangiosarcoma/virología , Hemangiosarcoma/genética , Hemangiosarcoma/patología , Sarcoma de Kaposi/virología , Sarcoma de Kaposi/patología , Genoma Viral , Humanos , Antígenos Virales/genética , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , Factor A de Crecimiento Endotelial Vascular/metabolismo , Factor A de Crecimiento Endotelial Vascular/genética , Ganciclovir/uso terapéutico , Ganciclovir/farmacología , Interleucina-10/genética

RESUMEN

BACKGROUND: Clinically, most patients with Kaposi's sarcoma (KS) are male, and several direct and indirect mechanisms may underlie this increased susceptibility in men, Kaposi's sarcoma-associated herpesvirus (KSHV), also known as human herpesvirus 8 (HHV-8), is considered to be the primary etiological agent responsible for KS. Thus, we propose the hypothesis that men are more susceptible to HHV-8 infection, leading to a higher incidence of Kaposi's sarcoma among males. A meta-analysis was conducted to evaluate the association between gender and HHV-8 seropositivity in the general population. METHODS: A comprehensive literature search was performed using 6 online databases: PubMed, EMBASE, Cochrane library, Web of Science, CNKI, and Wanfang. Studies published before March 15, 2023, were included. RESULTS: In all, 33 articles including 41 studies were included in the meta-analysis. In the included adult population. men had a higher risk of HHV-8 infection than did women in adult populations from all over the world (odds ratio [OR]: 1.08, 95% confidence interval [CI]: 1.01-1.15), but no differences were found in child population from all over the world (OR: 0.90, 95% CI: 0.79-1.01). There was a significant difference in HHV-8 seroprevalence between men and women in sub-Saharan Africa (SSA) adult population (OR: 1.15, 95% CI: 1.05-1.26). However, no significant differences were observed in sub-Saharan Africa (SSA) child population (OR: 0.90, 95%CI 0.78-1.03). As for other continents, the results showed no significant difference, such as the Asian population (OR: 1.03, 95%CI: 0.92-1.16). or the European and American populations (OR 1.01, 95%CI 0.87-1.17). CONCLUSION: There was a slight gender disparity for HHV-8 infection in the adult population. Among the adult populations from SSA and globally, men were more likely to be infected with HHV-8 than were women. However, no statistical significance was observed in the child populations from SSA and globally. In the future, the inclusion of more standardized studies may strengthen the results of this study.

Asunto(s)

Infecciones por Herpesviridae , Herpesvirus Humano 8 , Sarcoma de Kaposi , Humanos , Masculino , Femenino , Infecciones por Herpesviridae/epidemiología , Infecciones por Herpesviridae/virología , Sarcoma de Kaposi/epidemiología , Sarcoma de Kaposi/virología , Factores Sexuales , Adulto , Incidencia , Factores de Riesgo , Niño

RESUMEN

OBJECTIVE: Kaposi sarcoma is a vascular tumor that affects the pulmonary system. However, the diagnosis of airway lesions suggestive of pulmonary Kaposi sarcoma (pKS) is reliant on bronchoscopic visualization. We evaluated the role of Kaposi sarcoma herpesvirus (KSHV) viral load in bronchoalveolar lavage (BAL) as a diagnostic biomarker in patients with bronchoscopic evidence of pKS and evaluated inflammatory cytokine profiles in BAL and blood samples. DESIGN: In this retrospective study, we evaluated KSHV viral load and cytokine profiles within BAL and blood samples in patients who underwent bronchoscopy for suspected pKS between 2016 and 2021. METHODS: KSHV viral load and cytokine profiles were obtained from both the circulation and BAL samples collected at the time of bronchoscopy to evaluate compartment-specific characteristics. BAL was centrifuged and stored as cell pellets and KSHV viral load was measured using primers for the KSHV K6 gene regions. RESULTS: We evaluated 38 BAL samples from 32 patients (30 with HIV co-infection) of whom 23 had pKS. In patients with airway lesions suggestive of pKS, there was higher KSHV viral load (median 3188 vs. 0 copies/10 6 cell equivalent; P  = 0.0047). A BAL KSHV viral load cutoff of 526 copies/10 6 cells had a sensitivity of 72% and specificity of 89% in determining lesions consistent with pKS. Those with pKS also had higher IL-1ß and IL-8 levels in BAL. The 3-year survival rate for pKS patients was 55%. CONCLUSION: KSHV viral load in BAL shows potential for aiding in pKS diagnosis. Patients with pKS also have evidence of cytokine dysregulation in BAL.

Asunto(s)

Líquido del Lavado Bronquioalveolar , Citocinas , Herpesvirus Humano 8 , Sarcoma de Kaposi , Carga Viral , Humanos , Sarcoma de Kaposi/virología , Sarcoma de Kaposi/diagnóstico , Herpesvirus Humano 8/aislamiento & purificación , Masculino , Femenino , Estudios Retrospectivos , Persona de Mediana Edad , Líquido del Lavado Bronquioalveolar/virología , Líquido del Lavado Bronquioalveolar/citología , Adulto , Citocinas/análisis , Broncoscopía , Neoplasias Pulmonares/diagnóstico , Neoplasias Pulmonares/virología , Neoplasias Pulmonares/patología , Biomarcadores/análisis , Infecciones por VIH/complicaciones , Infecciones por VIH/diagnóstico , Anciano , Lavado Broncoalveolar

Asunto(s)

Herpesvirus Humano 8 , Linfohistiocitosis Hemofagocítica , Sarcoma de Kaposi , Humanos , Linfohistiocitosis Hemofagocítica/diagnóstico , Linfohistiocitosis Hemofagocítica/virología , Diagnóstico Diferencial , Sarcoma de Kaposi/diagnóstico , Sarcoma de Kaposi/virología , Herpesvirus Humano 8/aislamiento & purificación , Masculino , Síndrome de Liberación de Citoquinas/diagnóstico , Persona de Mediana Edad

RESUMEN

Protein knockdown with an inducible degradation system is a powerful tool for studying proteins of interest in living cells. Here, we adopted the auxin-inducible degron (AID) approach to detail Kaposi's sarcoma-associated herpesvirus (KSHV) latency-associated nuclear antigen (LANA) function in latency maintenance and inducible viral lytic gene expression. We fused the mini-auxin-inducible degron (mAID) tag at the LANA N-terminus with KSHV bacterial artificial chromosome 16 recombination, and iSLK cells were stably infected with the recombinant KSHV encoding mAID-LANA. Incubation with 5-phenyl-indole-3-acetic acid, a derivative of natural auxin, rapidly degraded LANA within 1.5 h. In contrast to our hypothesis, depletion of LANA alone did not trigger lytic reactivation but rather decreased inducible lytic gene expression when we stimulated reactivation with a combination of ORF50 protein expression and sodium butyrate. Decreased overall lytic gene induction seemed to be associated with a rapid loss of KSHV genomes in the absence of LANA. The rapid loss of viral genomic DNA was blocked by a lysosomal inhibitor, chloroquine. Furthermore, siRNA-mediated knockdown of cellular innate immune proteins, cyclic AMP-GMP synthase (cGAS) and simulator of interferon genes (STING), and other autophagy-related genes rescued the degradation of viral genomic DNA upon LANA depletion. Reduction of the viral genome was not observed in 293FT cells that lack the expression of cGAS. These results suggest that LANA actively prevents viral genomic DNA from sensing by cGAS-STING signaling axis, adding novel insights into the role of LANA in latent genome maintenance.IMPORTANCESensing of pathogens' components is a fundamental cellular immune response. Pathogens have therefore evolved strategies to evade such cellular immune responses. KSHV LANA is a multifunctional protein and plays an essential role in maintaining the latent infection by tethering viral genomic DNA to the host chromosome. We adopted the inducible protein knockdown approach and found that depletion of LANA induced rapid degradation of viral genomic DNA, which is mediated by innate immune DNA sensors and autophagy pathway. These observations suggest that LANA may play a role in hiding KSHV episome from innate immune DNA sensors. Our study thus provides new insights into the role of LANA in latency maintenance.

Asunto(s)

Antígenos Virales , Herpesvirus Humano 8 , Plásmidos , Sarcoma de Kaposi , Humanos , Antígenos Virales/metabolismo , ADN , Herpesvirus Humano 8/fisiología , Ácidos Indolacéticos , Nucleotidiltransferasas/genética , Sarcoma de Kaposi/virología , Latencia del Virus , Proteínas Nucleares/metabolismo