A Neuron-Specific Host MicroRNA Targets Herpes Simplex Virus-1 ICP0 Expression and Promotes Latency

Pan, Dongli; Flores, Omar Gabriel Mejí­a; Umbach, Jennifer L.; Pesola, Jean M.; Bentley, Peris; Rosato, Pamela C.; Leib, David A.; Cullen, Bryan R.; Coen, Donald M.

doi:10.1016/j.chom.2014.03.004

Cited by 133 publications

(146 citation statements)

References 67 publications

(68 reference statements)

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“…Maillet et al noted nuclear accumulation of ICP0 in mouse TG neurons during latency (38). Indeed, a recent study suggests that in mouse neuronal cells, miR138 specifically targets ICP0 transcript, prevents its translation, and increases its degradation (58). A similar mechanism might be operating in tree shrew TG neurons as well.…”

Section: Discussionmentioning

confidence: 97%

Herpes Simplex Virus 1 Infection of Tree Shrews Differs from That of Mice in the Severity of Acute Infection and Viral Transcription in the Peripheral Nervous System

Wang

et al. 2016

J Virol

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Studies of herpes simplex virus (HSV) infections of humans are limited by the use of rodent models such as mice, rabbits, and guinea pigs. Tree shrews (Tupaia belangeri chinensis) are small mammals indigenous to southwest Asia. At behavioral, anatomical, genomic, and evolutionary levels, tree shrews are much closer to primates than rodents are, and tree shrews are susceptible to HSV infection. Thus, we have studied herpes simplex virus 1 (HSV-1) infection in the tree shrew trigeminal ganglion (TG) following ocular inoculation. In situ hybridization, PCR, and quantitative reverse transcription-PCR (qRT-PCR) analyses confirm that HSV-1 latently infects neurons of the TG. When explant cocultivation of trigeminal ganglia was performed, the virus was recovered after 5 days of cocultivation with high efficiency. Swabbing the corneas of latently infected tree shrews revealed that tree shrews shed virus spontaneously at low frequencies. However, tree shrews differ significantly from mice in the expression of key HSV-1 genes, including ICP0, ICP4, and latency-associated transcript (LAT). In acutely infected tree shrew TGs, no level of ICP4 was observed, suggesting the absence of infection or a very weak, acute infection compared to that of the mouse. Immunofluorescence staining with ICP4 monoclonal antibody, and immunohistochemistry detection by HSV-1 polyclonal antibodies, showed a lack of viral proteins in tree shrew TGs during both acute and latent phases of infection. Cultivation of supernatant from homogenized, acutely infected TGs with RS1 cells also exhibited an absence of infectious HSV-1 from tree shrew TGs. We conclude that the tree shrew has an undetectable, or a much weaker, acute infection in the TGs. Interestingly, compared to mice, tree shrew TGs express high levels of ICP0 transcript in addition to LAT during latency. However, the ICP0 transcript remained nuclear, and no ICP0 protein could be seen during the course of mouse and tree shrew TG infections. Taken together, these observations suggest that the tree shrew TG infection differs significantly from the existing rodent models. IMPORTANCEHerpes simplex viruses (HSVs) establish lifelong infection in more than 80% of the human population, and their reactivation leads to oral and genital herpes. Currently, rodent models are the preferred models for latency studies. Rodents are distant from primates and may not fully represent human latency. The tree shrew is a small mammal, a prosimian primate, indigenous to southwest Asia. In an attempt to further develop the tree shrew as a useful model to study herpesvirus infection, we studied the establishment of latency and reactivation of HSV-1 in tree shrews following ocular inoculation. We found that the latent virus, which resides in the sensory neurons of the trigeminal ganglion, could be stress reactivated to produce infectious virus, following explant cocultivation and that spontaneous reactivation could be detected by cell culture of tears. Interestingly, the tree shrew model is quite different from...

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Section: Discussionmentioning

confidence: 97%

Herpes Simplex Virus 1 Infection of Tree Shrews Differs from That of Mice in the Severity of Acute Infection and Viral Transcription in the Peripheral Nervous System

Wang

et al. 2016

J Virol

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“…Intriguingly, it may also result from microRNA (miRNA)-mediated translational repression, as a viral microRNA, miR-UL36, has been reported to downregulate UL138 (53) and is expressed during both experimental and natural latent infections (54). Regulation by cellular miRNAs is also possible, as has been detected for viral IE1 transcripts in latently infected cells (22,55). The very low levels of UL138 proteins detected are consistent with viral attempts at immune evasion during latency, as UL138 possesses known cytotoxic T-cell-specific epitopes (56).…”

Section: Discussionmentioning

confidence: 99%

Long and Short Isoforms of the Human Cytomegalovirus UL138 Protein Silence IE Transcription and Promote Latency

Lee

Caviness

Albright

et al. 2016

J Virol

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The UL133-138 locus present in clinical strains of human cytomegalovirus (HCMV) encodes proteins required for latency and reactivation in CD34؉ hematopoietic progenitor cells and virion maturation in endothelial cells. The encoded proteins form multiple homo-and hetero-interactions and localize within secretory membranes. One of these genes, UL136 gene, is expressed as at least five different protein isoforms with overlapping and unique functions. Here we show that another gene from this locus, the UL138 gene, also generates more than one protein isoform. A long form of UL138 (pUL138-L) initiates translation from codon 1, possesses an amino-terminal signal sequence, and is a type one integral membrane protein. Here we identify a short protein isoform (pUL138-S) initiating from codon 16 that displays a subcellular localization similar to that of pUL138-L. Reporter, short-term transcription, and long-term virus production assays revealed that both pUL138-L and pUL138-S are able to suppress major immediate early (IE) gene transcription and the generation of infectious virions in cells in which HCMV latency is studied. The long form appears to be more potent at silencing IE transcription shortly after infection, while the short form seems more potent at restricting progeny virion production at later times, indicating that both isoforms of UL138 likely cooperate to promote HCMV latency. IMPORTANCELatency allows herpesviruses to persist for the lives of their hosts in the face of effective immune control measures for productively infected cells. Controlling latent reservoirs is an attractive antiviral approach complicated by knowledge deficits for how latently infected cells are established, maintained, and reactivated. This is especially true for betaherpesviruses. The functional consequences of HCMV UL138 protein expression during latency include repression of viral IE1 transcription and suppression of virus replication. Here we show that short and long isoforms of UL138 exist and can themselves support latency but may do so in temporally distinct manners. Understanding the complexity of gene expression and its impact on latency is important for considering potential antivirals targeting latent reservoirs. Human cytomegalovirus (HCMV) is a betaherpesvirus that causes birth defects and disease in immunocompromised and immunosuppressed patients and has been associated with cancers, cardiovascular disease, and immune dysfunction (1-3). HCMV productively (lytically) infects differentiated cells, such as fibroblasts, endothelial cells, and epithelial cells, and latently infects incompletely differentiated cells of the myeloid lineage, such as monocytes and CD34 ϩ hematopoietic progenitor cells (HPC) (4, 5). Productive infection in multiple cell types within the human host facilitates viral dissemination, while latency ensures lifelong persistence despite an effective immune response against lyticphase antigens. Periodic reactivations of latent infections into the productive phase perpetuate both lifelong infecti...

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“…The effect of miRNA on HSV-1 gene expression is not limited to virus-encoded miRNA. Recently, a neuronal-specific miRNA (miR-138) has been shown to target sequences within HSV-1 ICP0/RF2, reducing ICP0 expression and thus expression of most lytic virus genes (Pan et al, 2014). In addition, two small (961 and 36 nt) HSV-1 RNAs reduce expression of HSV-1 ICP4, productive virus yields and cold shock-induced apoptosis (Shen et al, 2009).…”

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confidence: 99%

A comparison of herpes simplex virus type 1 and varicella-zoster virus latency and reactivation

Kennedy

Rovnak

Badani

et al. 2015

Journal of General Virology

133

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Herpes simplex virus type 1 (HSV-1; human herpesvirus 1) and varicella-zoster virus (VZV; human herpesvirus 3) are human neurotropic alphaherpesviruses that cause lifelong infections in ganglia. Following primary infection and establishment of latency, HSV-1 reactivation typically results in herpes labialis (cold sores), but can occur frequently elsewhere on the body at the site of primary infection (e.g. whitlow), particularly at the genitals. Rarely, HSV-1 reactivation can cause encephalitis; however, a third of the cases of HSV-1 encephalitis are associated with HSV-1 primary infection. Primary VZV infection causes varicella (chickenpox) following which latent virus may reactivate decades later to produce herpes zoster (shingles), as well as an increasingly recognized number of subacute, acute and chronic neurological conditions. Following primary infection, both viruses establish a latent infection in neuronal cells in human peripheral ganglia. However, the detailed mechanisms of viral latency and reactivation have yet to be unravelled. In both cases latent viral DNA exists in an 'end-less' state where the ends of the virus genome are joined to form structures consistent with unit length episomes and concatemers, from which viral gene transcription is restricted. In latently infected ganglia, the most abundantly detected HSV-1 RNAs are the spliced products originating from the primary latency associated transcript (LAT). This primary LAT is an 8.3 kb unstable transcript from which two stable (1.5 and 2.0 kb) introns are spliced. Transcripts mapping to 12 VZV genes have been detected in human ganglia removed at autopsy; however, it is difficult to ascribe these as transcripts present during latent infection as early-stage virus reactivation may have transpired in the post-mortem time period in the ganglia. Nonetheless, low-level transcription of VZV ORF63 has been repeatedly detected in multiple ganglia removed as close to death as possible. There is increasing evidence that HSV-1 and VZV latency is epigenetically regulated. In vitro models that permit pathway analysis and identification of both epigenetic modulations and global transcriptional mechanisms of HSV-1 and VZV latency hold much promise for our future understanding in this complex area. This review summarizes the molecular biology of HSV-1 and VZV latency and reactivation, and also presents future directions for study. Received 5 January 2015Accepted 18 March 2015 IntroductionHerpes simplex virus type 1 (HSV-1; human herpesvirus 1) and varicella-zoster virus (VZV; human herpesvirus 3) are human neurotropic alphaherpesviruses usually acquired early in life. Primary HSV-1 infection is usually localized and may be asymptomatic, although it can produce a more widespread systemic infection in neonates and immunocompromised adults, whilst primary VZV infection is systemic and results in childhood varicella (chickenpox). During primary infection, both viruses gain access to neurons most likely through retrograde transport from the site of cutaneous lesion...

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A Neuron-Specific Host MicroRNA Targets Herpes Simplex Virus-1 ICP0 Expression and Promotes Latency

Cited by 133 publications

References 67 publications

Herpes Simplex Virus 1 Infection of Tree Shrews Differs from That of Mice in the Severity of Acute Infection and Viral Transcription in the Peripheral Nervous System

Herpes Simplex Virus 1 Infection of Tree Shrews Differs from That of Mice in the Severity of Acute Infection and Viral Transcription in the Peripheral Nervous System

Long and Short Isoforms of the Human Cytomegalovirus UL138 Protein Silence IE Transcription and Promote Latency

A comparison of herpes simplex virus type 1 and varicella-zoster virus latency and reactivation

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