scholarly journals Reactivation of Herpes Simplex Virus (HSV) from Latency in Response to Neuronal Hyperexcitability

Proceedings ◽  
2020 ◽  
Vol 50 (1) ◽  
pp. 91
Author(s):  
Sean Cuddy ◽  
Austin Schinlever ◽  
Sara Dochnal ◽  
Jon Suzich ◽  
Mina Farah ◽  
...  

Herpes Simplex Virus (HSV) establishes a latent infection in neurons, in which viral transcription is restricted and viral promoters are associated with heterochromatin. In response to certain stimuli, the virus reactivates to permit transmission. The exact physiological triggers of reactivation, the cell signaling pathways involved, and how signals act on heterochromatin-associated lytic promoters, are not understood. Previously, we identified a role for a neural stress pathway involving DLK and JNK activity in HSV reactivation, triggered by nerve growth factor (NGF) deprivation. Reactivation was associated with a JNK-dependent histone phospho/methyl switch on lytic gene promoters. Because the same histone phospho/methyl switch occurs in cortical neurons following hyperexcitability (triggered by forskolin), we examined whether HSV reactivation was linked to hyperexcitability, and the contribution of JNK activity and histone phosphorylation. Using our primary neuronal model of HSV reactivation, we found that forskolin triggered DLK/JNK-dependent reactivation via a pathway that was distinct from NGF deprivation. The initial burst of HSV lytic gene expression in response to forskolin occurred independently of histone demethylase activity, and was accompanied by a histone phospho/methyl switch. To determine whether forskolin-mediated reactivation was linked to neuronal activity, we investigated the contribution of ion channel activity. Inhibition of voltage-gated potassium and sodium channels, or hyperpolarization-activated cyclic nucleotide-gated channels, prevented forskolin-mediated reactivation. In addition, hyperexcitability, resulting from the removal of a tetrodotoxin block, triggered HSV reactivation in a DLK/JNK-dependent manner. We next investigated whether physiological triggers induce HSV reactivation via hyperexcitability. IL-1 induced DNA damage associated with hyperexcitability in adult neurons. IL-1 also triggered DLK/JNK-dependent HSV reactivation, which was dependent on ion channel activity. Therefore, these data indicate that neuronal hyperexcitability in response to physiological stimuli, such as inflammation, trigger HSV reactivation, and mark out the activation of DLK/JNK and a histone phospho/methyl switch as key events in the hyperexcitability-mediated reactivation.

2009 ◽  
Vol 84 (1) ◽  
pp. 565-572 ◽  
Author(s):  
Rodolfo D. Vicetti Miguel ◽  
Brian S. Sheridan ◽  
Stephen A. K. Harvey ◽  
Robert S. Schreiner ◽  
Robert L. Hendricks ◽  
...  

ABSTRACT Correlations between estrogen and herpes simplex virus (HSV) reactivation from latency have been suggested by numerous clinical reports, but causal associations are not well delineated. In a murine HSV-1 corneal infection model, we establish 17-β estradiol (17-βE) treatment of latently infected ovariectomized mice induces viral reactivation, as demonstrated by increased viral load and increased immediate-early viral gene expression in the latently infected trigeminal ganglia (TG). Interestingly, the increased HSV reactivation occurred in the absence of inhibition of viral specific CD8+ T-cell effector function. 17-βE administration increased HSV reactivation in CD45+ cell-depleted TG explant cultures, providing further support that leukocyte-independent effects on latently infected neurons were responsible for the increased reactivation. The drug-induced increases in HSV copy number were not recapitulated upon in vivo treatment of latently infected estrogen receptor alpha-deficient mice, evidence that HSV reactivation promoted by 17-βE was estrogen receptor dependent. These findings provide additional framework for the emerging conceptualization of HSV latency as a dynamic process maintained by complex interactions among multiple cooperative and competing host, viral, and environmental forces. Additional research is needed to confirm whether pregnancy or hormonal contraceptives containing 17-βE also promote HSV reactivation from latency in an estrogen receptor-dependent manner.


Author(s):  
Giovanna De Chiara ◽  
Mauro Racaniello ◽  
Cristiana Mollinari ◽  
Maria Elena Marcocci ◽  
Giorgia Aversa ◽  
...  

2000 ◽  
Vol 74 (2) ◽  
pp. 934-943 ◽  
Author(s):  
Rui Lu ◽  
Vikram Misra

ABSTRACT The cascade of herpes simplex virus (HSV) gene expression that results in viral replication begins with the activation of viral immediate-early (IE) genes by the virion-associated protein VP16. VP16 on its own is inefficient at associating with complexes formed on IE gene promoters and depends upon the cellular factor HCF for its activity. In this respect VP16 mimics the host basic leucine zipper (bZIP) protein Luman, which also requires HCF for activating transcription. Our objective is to explore interactions between Luman and HCF and to determine if they play a role in the biology of herpesviruses. In this report we show that in cultured cells ectopically expressed Luman was retained in the cytoplasm, where it colocalized with Calnexin, a protein normally associated with the endoplasmic reticulum (ER). Retention of Luman in the ER depends on a hydrophobic segment of the protein that probably serves as a transmembrane domain. Deletion of this domain changed the intracellular location of Luman so that most of the mutant protein was in the nucleus of cells. While HCF was present in the nucleus of most cells, in cells expressing Luman it was retained in the cytoplasm where the two proteins colocalized. This cytoplasmic association of Luman and HCF could also be demonstrated in neurons in trigeminal ganglia removed from cattle soon after death. Cells in tissue culture that expressed Luman, but not a mutant form of the protein that fails to bind HCF, were resistant to a productive infection with HSV type 1 (HSV-1). We hypothesize that similar Luman-HCF interactions in sensory neurons in trigeminal ganglia result in the suppression of viral replication and the establishment of latency. Interestingly, Luman could activate the promoters of IE110 and LAT, two genes that are critical for reactivation of HSV-1 from latency. This suggests a role for Luman in the reactivation process as well.


2016 ◽  
Vol 113 (43) ◽  
pp. 12256-12261 ◽  
Author(s):  
Shuang Tang ◽  
Amita Patel ◽  
Philip R. Krause

The herpes simplex virus (HSV) infected cell culture polypeptide 27 (ICP27) protein is essential for virus infection of cells. Recent studies suggested that ICP27 inhibits splicing in a gene-specific manner via an unknown mechanism. Here, RNA-sequencing revealed that ICP27 not only inhibits splicing of certain introns in <1% of cellular genes, but also can promote use of alternative 5′ splice sites. In addition, ICP27 induced expression of pre-mRNAs prematurely cleaved and polyadenylated from cryptic polyadenylation signals (PAS) located in intron 1 or 2 of ∼1% of cellular genes. These previously undescribed prematurely cleaved and polyadenylated pre-mRNAs, some of which contain novel ORFs, were typically intronless, <2 Kb in length, expressed early during viral infection, and efficiently exported to cytoplasm. Sequence analysis revealed that ICP27-targeted genes are GC-rich (as are HSV genes), contain cytosine-rich sequences near the 5′ splice site, and have suboptimal splice sites in the impacted intron, suggesting that a common mechanism is shared between ICP27-mediated alternative polyadenylation and splicing. Optimization of splice site sequences or mutation of nearby cytosines eliminated ICP27-mediated splicing inhibition, and introduction of C-rich sequences to an ICP27-insensitive splicing reporter conferred this phenotype, supporting the inference that specific gene sequences confer susceptibility to ICP27. Although HSV is the first virus and ICP27 is the first viral protein shown to activate cryptic PASs in introns, we suspect that other viruses and cellular genes also encode this function.


2000 ◽  
Vol 74 (3) ◽  
pp. 1355-1363 ◽  
Author(s):  
Guo-Jie Ye ◽  
Kevin T. Vaughan ◽  
Richard B. Vallee ◽  
Bernard Roizman

ABSTRACT To express the function encoded in its genome, the herpes simplex virus 1 capsid-tegument structure released by deenvelopment during entry into cells must be transported retrograde to the nuclear pore where viral DNA is released into the nucleus. This path is essential in the case of virus entering axons of dorsal root ganglia. The objective of the study was to identify the viral proteins that may be involved in the transport. We report the following findings. (i) The neuronal isoform of the intermediate chain (IC-1a) of the dynein complex pulled down, from lysates of [35S]methionine-labeled infected cells, two viral proteins identified as the products of UL34 and UL31 open reading frames, respectively. UL34 protein is a virion protein associated with cellular membranes and phosphorylated by the viral kinase US3. UL31 protein is a largely insoluble, evenly dispersed nuclear phosphoprotein required for optimal processing and packaging of viral DNA into preformed capsids. Reciprocal pulldown experiments verified the interaction of IC-1a and UL34 protein. In similar experiments, UL34 protein was found to interact with UL31 protein and the major capsid protein ICP5. (ii) To determine whether UL34 protein is transported to the nuclear membrane, a requirement if it is involved in transport, the UL34 protein was inserted into a baculovirus vector under the cytomegalovirus major early promoter. Cells infected with the recombinant baculovirus expressed UL34 protein in a dose-dependent manner, and the UL34 protein localized primarily in the nuclear membrane. An unexpected finding was that UL34-expressing cells showed a dissociation of the inner and outer nuclear membranes reminiscent of the morphologic changes seen in cells productively infected with herpes simplex virus 1. UL34, like many other viral proteins, may have multiple functions expressed both early and late in infection.


2005 ◽  
Vol 79 (7) ◽  
pp. 4090-4098 ◽  
Author(s):  
Wei-Li Hsu ◽  
Holly A. Saffran ◽  
James R. Smiley

ABSTRACT Herpes simplex virus (HSV) virion host shutoff protein (vhs) destabilizes cellular and viral mRNAs. Previous work from several laboratories has indicated that vhs accelerates the turnover of most host mRNAs and provided evidence that at least some of these are degraded via endonucleolytic cleavage near regions of translational initiation followed by 5′→3′ decay. In contrast, several recent reports have argued that vhs is selective, preferentially targeting a subset of mRNAs including some that bear AU-rich instability elements (such as the stress-inducible IEX-1 mRNA). These reports concluded that vhs triggers deadenylation, 3′ cleavage, and 3′→5′ decay of IEX-1 mRNA. However, we report here that HSV infection does not increase the rate of degradation of IEX-1 mRNA; rather, actinomycin D chase assays indicate that the transcript is stabilized relative to that in uninfected cells in both the presence and absence of functional vhs. Moreover, deadenylated but otherwise intact IEX-1 mRNA was readily detected in uninfected cells cultured under our experimental conditions, and its relative abundance did not increase following HSV type 1 (HSV-1) infection. We confirm that HSV infection increases the relative abundance of a discrete 0.75-kb 3′-truncated IEX-1 RNA species in a vhs-dependent manner. This truncated transcript was also detected (albeit at lower levels) in cells infected with vhs mutants and in uninfected cells, where it increased in abundance in response to tumor necrosis factor alpha, cycloheximide, and puromycin. We conclude that IEX-1 mRNA is not preferentially degraded during HSV-1 infection and that HSV-1 instead inhibits the normal turnover of this mRNA.


2004 ◽  
Vol 78 (22) ◽  
pp. 12508-12518 ◽  
Author(s):  
Nicole J. Kubat ◽  
Antonio L. Amelio ◽  
Nicole V. Giordani ◽  
David C. Bloom

ABSTRACT During herpes simplex virus type 1 (HSV-1) latency, only one region of the viral genome is actively transcribed: the region encoding the latency-associated transcript (LAT). A previous study demonstrated that during latency the LAT promoter is hyperacetylated at histone H3 (K9, K14) relative to lytic genes examined. In the present study, we examine the acetylation profile of regions downstream of the LAT promoter during a latent infection of murine dorsal root ganglia. These analyses revealed the following: (i) the region of the genome containing the 5′ exon of the LAT primary transcript was at least as enriched in acetylated H3 as the LAT promoter, and (ii) the region of hyperacetylation does not extend to the ICP0 promoter. In order to assess the contribution of LAT transcription to the acetylation of the 5′ exon region, the acetylation profile of KOS/29, a recombinant with a deletion of the LAT promoter, was examined. The region containing the 5′ exon of KOS/29 was hyperacetylated relative to lytic gene regions in the absence of detectable LAT transcription. These results indicate that the region containing the 5′ exon of LAT, known to contain enhancer activities and to be critical for induced reactivation (rcr), exists in a chromatin structure during latency that is distinct from other lytic gene regions. This result suggests a role for the 5′ exon LAT enhancer region as a cis-acting regulator of transcription that maintains a transcriptionally permissive chromatin domain in the HSV-1 latent episome.


2007 ◽  
Vol 4 (9) ◽  
pp. 692-693
Author(s):  
Daniel N Cortright ◽  
Marianne E Buck ◽  
James E Krause

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