scholarly journals HCMV exploits STING signaling and counteracts IFN and ISG induction to facilitate dendritic cell infection

Author(s):  
Bibiana Costa ◽  
Jennifer Becker ◽  
Tobias Krammer ◽  
Felix Mulenge ◽  
Verónica Durán ◽  
...  

Abstract Human cytomegalovirus (HCMV) is a widespread obligatory human pathogen causing life-threatening disease in immunocompromised hosts. Myeloid cells such as monocyte-derived dendritic cells (moDCs) are targets of HCMV. Here, we performed single-cell RNA sequencing, which revealed infection of most moDCs upon in vitro HCMV exposure, whereas only a fraction of them initiated viral gene expression. We identified three moDC subsets, of which CD1a−/CD86− cells showed the highest susceptibility. Upon HCMV entry, STING activation not only induced IFN-β, but also promoted viral gene expression. Upon progression of infection, IFN-β but not IFN-λ1 expression was inhibited. Similarly, ISG expression was initially induced and then shut off and thus allowed productive infection. Increased viral gene expression was associated with the induction of several pro- (RHOB, HSP1A1, DNAJB1) and anti-viral (RNF213, TNFSF10, IFI16) genes. Thus, moDC permissiveness to HCMV depends on complex interactions between virus sensing, regulation of IFNs/ISGs and viral gene expression.

2007 ◽  
Vol 81 (8) ◽  
pp. 3949-3968 ◽  
Author(s):  
Sathish Sadagopan ◽  
Neelam Sharma-Walia ◽  
Mohanan Valiya Veettil ◽  
Hari Raghu ◽  
Ramu Sivakumar ◽  
...  

ABSTRACT In vitro Kaposi's sarcoma-associated herpesvirus (KSHV) infection of primary human dermal microvascular endothelial (HMVEC-d) cells and human foreskin fibroblast (HFF) cells is characterized by the induction of preexisting host signal cascades, sustained expression of latency-associated genes, transient expression of a limited number of lytic genes, and induction of several cytokines, growth factors, and angiogenic factors. Since NF-κB is a key molecule involved in the regulation of several of these factors, here, we examined NF-κB induction during de novo infection of HMVEC-d and HFF cells. Activation of NF-κB was observed as early as 5 to 15 min postinfection by KSHV, and translocation of p65-NF-κB into nuclei was detected by immunofluorescence assay, electrophoretic mobility shift assay, and p65 enzyme-linked immunosorbent assay. IκB phosphorylation inhibitor (Bay11-7082) reduced this activation significantly. A sustained moderate level of NF-κB induction was seen during the observed 72 h of in vitro KSHV latency. In contrast, high levels of ERK1/2 activation at earlier time points and a moderate level of activation at later times were observed. p38 mitogen-activated protein kinase was activated only at later time points, and AKT was activated in a cyclic manner. Studies with UV-inactivated KSHV suggested a role for virus entry stages in NF-κB induction and a requirement for KSHV viral gene expression in sustained induction. Inhibition of NF-κB did not affect target cell entry by KSHV but significantly reduced the expression of viral latent open reading frame 73 and lytic genes. KSHV infection induced the activation of several host transcription factors, including AP-1 family members, as well as several cytokines, growth factors, and angiogenic factors, which were significantly affected by NF-κB inhibition. These results suggest that during de novo infection, KSHV induces sustained levels of NF-κB to regulate viral and host cell genes and thus possibly regulates the establishment of latent infection.


2011 ◽  
Vol 112 (1) ◽  
pp. 307-317 ◽  
Author(s):  
Maria-Cristina Arcangeletti ◽  
Isabella Rodighiero ◽  
Prisco Mirandola ◽  
Flora De Conto ◽  
Silvia Covan ◽  
...  

Author(s):  
Werner J. D. Ouwendijk ◽  
Daniel P. Depledge ◽  
Labchan Rajbhandari ◽  
Tihana Lenac Rovis ◽  
Stipan Jonjic ◽  
...  

SummaryVaricella-zoster virus (VZV) establishes lifelong neuronal latency in most humans world-wide, reactivating in one-third to cause herpes zoster and occasionally chronic pain. How VZV establishes, maintains and reactivates from latency is largely unknown. Latent VZV gene expression is restricted to VZV latency-associated transcript (VLT) and open reading frame 63 (ORF63) in naturally VZV-infected human trigeminal ganglia (TG). Notably, these transcript levels positively correlated suggesting co-regulated transcription during latency. Here, we used direct RNA-sequencing to identify fusion transcripts that combine VLT and ORF63 loci (VLT-ORF63) and are expressed during both lytic and latent VZV infections. Furthermore, real-time PCR, RNA in situ hybridization and 5’ rapid amplification of cDNA ends (RACE) all confirmed VLT-ORF63, but not canonical ORF63, expression in human TG. During lytic infection, one of the two major VLT-ORF63 isoforms encodes a novel fusion protein combining VLT and ORF63 proteins (pVLT-ORF63). In vitro, VLT is transcribed in latently VZV-infected human sensory neurons, whereas VLT-ORF63 expression is induced by reactivation stimuli. Moreover, the pVLT-ORF63-encoding VLT-ORF63 isoform induced transcription of lytic VZV genes. Collectively, our findings show that VZV expresses a unique set of VLT-ORF63 transcripts, potentially involved in the transition from latency to lytic VZV infection.


mBio ◽  
2016 ◽  
Vol 7 (1) ◽  
Author(s):  
Thomas M. Kristie

ABSTRACT Like their cellular hosts, herpesviruses are subject to the regulatory impacts of chromatin assembled on their genomes. Upon infection, these viruses are assembled into domains of chromatin with heterochromatic signatures that suppress viral gene expression or euchromatic characteristics that promote gene expression. The organization and modulation of these chromatin domains appear to be intimately linked to the coordinated expression of the different classes of viral genes and thus ultimately play an important role in the progression of productive infection or the establishment and maintenance of viral latency. A recent report from the Knipe laboratory (J. S. Lee, P. Raja, and D. M. Knipe, mBio 7:e02007-15, 2016) contributes to the understanding of the dynamic modulation of chromatin assembled on the herpes simplex virus genome by monitoring the levels of characteristic heterochromatic histone modifications (histone H3 lysine 9 and 27 methylation) associated with a model viral early gene during the progression of lytic infection. Additionally, this study builds upon previous observations that the viral immediate-early protein ICP0 plays a role in reducing the levels of heterochromatin associated with the early genes.


2005 ◽  
Vol 86 (10) ◽  
pp. 2697-2702 ◽  
Author(s):  
Gail Henderson ◽  
Yange Zhang ◽  
Clinton Jones

The infected cell protein 0 (bICP0) encoded by Bovine herpesvirus 1 (BHV-1) stimulates viral gene expression and productive infection. As bICP0 is expressed constitutively during productive infection, it is considered to be the major viral regulatory protein. Like other alphaherpesvirus ICP0 homologues, bICP0 contains a zinc RING finger near its N terminus that activates transcription and regulates subcellular localization. In this study, evidence is provided that bICP0 represses the human beta interferon (IFN-β) promoter and a simple promoter with consensus IFN-stimulated response elements following stimulation with double-stranded RNA (polyinosinic–polycytidylic acid), IFN regulatory factor 3 (IRF3) or IRF7. bICP0 also inhibits the ability of two protein kinases (TBK1 and IKKε) to activate IFN-β promoter activity. The zinc RING finger is necessary for inhibiting IFN-dependent transcription in certain cell types. Collectively, these studies suggest that bICP0 activates productive infection by stimulating viral gene expression and inhibiting IFN-dependent transcription.


2019 ◽  
Vol 93 (21) ◽  
Author(s):  
Sebla B. Kutluay ◽  
Ann Emery ◽  
Srinivasa R. Penumutchu ◽  
Dana Townsend ◽  
Kasyap Tenneti ◽  
...  

ABSTRACT Alternative splicing of HIV-1 mRNAs increases viral coding potential and controls the levels and timing of gene expression. HIV-1 splicing is regulated in part by heterogeneous nuclear ribonucleoproteins (hnRNPs) and their viral target sequences, which typically repress splicing when studied outside their native viral context. Here, we determined the location and extent of hnRNP binding to HIV-1 mRNAs and their impact on splicing in a native viral context. Notably, hnRNP A1, hnRNP A2, and hnRNP B1 bound to many dispersed sites across viral mRNAs. Conversely, hnRNP H1 bound to a few discrete purine-rich sequences, a finding that was mirrored in vitro. hnRNP H1 depletion and mutation of a prominent viral RNA hnRNP H1 binding site decreased the use of splice acceptor A1, causing a deficit in Vif expression and replicative fitness. This quantitative framework for determining the regulatory inputs governing alternative HIV-1 splicing revealed an unexpected splicing enhancer role for hnRNP H1 through binding to its target element. IMPORTANCE Alternative splicing of HIV-1 mRNAs is an essential yet quite poorly understood step of virus replication that enhances the coding potential of the viral genome and allows the temporal regulation of viral gene expression. Although HIV-1 constitutes an important model system for general studies of the regulation of alternative splicing, the inputs that determine the efficiency with which splice sites are utilized remain poorly defined. Our studies provide an experimental framework to study an essential step of HIV-1 replication more comprehensively and in much greater detail than was previously possible and reveal novel cis-acting elements regulating HIV-1 splicing.


2005 ◽  
Vol 79 (1) ◽  
pp. 472-485 ◽  
Author(s):  
Claire Gealy ◽  
Marian Denson ◽  
Christine Humphreys ◽  
Brian McSharry ◽  
Gavin Wilkinson ◽  
...  

ABSTRACT Human cytomegalovirus (HCMV) has evolved multiple strategies for suppression of the antiviral response of the infected cell. DNA array technology has revealed that HCMV clearly regulates host gene expression during the course of a productive infection by enhancing, sustaining, or suppressing steady-state levels of cellular transcripts. Interleukin-6 (IL-6) is a pleiotropic cytokine that plays a central role in the immune response to infection. Here we report a detailed study of the effects of HCMV infection on IL-6 expression by human fibroblasts. UV-inactivated virus was found to induce high levels of IL-6 mRNA and protein expression, and IL-6 mRNA remained abundant in cells 16 h after inoculation even though the level of ongoing IL-6 transcription was not significantly enhanced. In lytic HCMV infections, the onset of viral gene expression resulted in two apparently antagonistic effects on IL-6 expression: (i) transcriptional activation, mediated at least in part by the IE2p86 protein, and (ii) posttranscriptional suppression mediated by destabilization of IL-6 mRNA. Transcriptional activation was outweighed by the suppressive effect, such that cells undergoing productive infection produced less IL-6 than cells challenged with inactivated virus. Suppression of IL-6 expression was independent of the viral IL-10 homologue, cmvIL-10. Destabilization of IL-6 mRNA was observed to coincide with the enhanced expression and aberrant intracellular localization of HuR, an mRNA-binding protein known to interact with IL-6 and other mRNAs containing 3′ AU-rich elements. Our data suggest a novel mechanism for gene regulation by HCMV at the posttranscriptional level.


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