Herpes simplex is a viral infection caused by the herpes simplex virus. Oral herpes involves the face or mouth. It may result in small blisters in groups often called cold sores or fever blisters or may just cause a sore throat. The most effective method of avoiding genital infections is by avoiding vaginal, oral, and anal sex. HSV infection causes zimplex distinct medical disorders.
Here we show that HSV-1 productive infection in cortical neurons causes the accumulation of DNA lesions that include both single SSBs and double strand breaks DSBswhich smplex reported to be implicated in the neuronal loss observed in neurodegenerative diseases.
Since HSV-1 usually causes life-long recurrent infections, it is possible to speculate that cumulating damages, including those occurring on DNA, may contribute to virus induced neurotoxicity and neurodegeneration, further suggesting HSV-1 as a risk factor for neurodegenerative conditions.
HSV-1 is an ubiquitous human pathogen causing recurrent hrepes manifestations mainly in epithelial cells of oralmucosa and perioral region, replicating in the nuclei of infected cells. After a primary infection, the virus is able to establish latency in the peripheral nervous ganglia that it reaches through anterograde axonal transport.
Following periodic reactivations, the neo-formed virions come simpoex to the site of primary infection, causing recurrent infections Dobson and Itzhaki, ; Roizman and Knipe, ; Mori et al.
The virus may repaiir reach the brain, targeting sipmlex same regions altered in AD, where it herpes establish latent simplex and periodically reactivate. Thus, beyond a massive brain infection, resulting in rare, but severe form of herpetic encephalitis, milder, but periodically repeated, cerebral infections may also occur.
These may cause damages that, accumulating over life, result in pathological outcomes in the elderly. Overall these data, allow us to hypothesize that HSV-1 may affect Virus repair systems in neurons, thus contributing to neurodegeneration through DNA the accumulation. Such an effect seems to be mainly related to a viral induced impairment of Hdrpes repair activity and, in particular, to a degradation of Ku80, one of the key factors of NHEJ pathway.
The authors certify that all ximplex experimental protocols used in the present study were in compliance with the European Guide for the Care and Use of Laboratory Animals and institutional guidelines and with the Italian legislation on animal experimentation Decreto L. Monolayers of kidney epithelial VERO cells were cultivated in 75 cm 2 tissue culture flasks and infected with HSV-1 strain F at a multiplicity of infection m.
Cell debris was removed with low-speed centrifugation, and virus titers virus measured by standard plaque assay Killington and Powell, C was added to inhibit glial proliferation. Seven to 9 days after plating, the culture medium was replaced with Neurobasal medium containing The Strain F at a m. The HSVcontaining medium was then simplex and, after two washes in phosphate buffered saline PBSthe cells were returned to the original medium and cultured for the indicated times.
Viral titer in the supernatants of infected cells was evaluated by standard plaque forming unit pfu assay Killington and Powell, Mock-infection was performed with conditioned medium from uninfected VERO cells by using the same dilution as that used for the virus. The quantitation of protein expression was determined after normalization to tubulin or actin by measuring the optical density of respective band blots using the Quantity One software Bio-Rad, Hercules, CA, USA.
In particular, cells with undamaged DNA do not migrate due to the lack of free ends and large size of Virus fragments, whereas cells with damaged DNA migrate and have the appearance of a comet with a bright fluorescent head simplex a tail repair length and fluorescent intensity are related to the number herpes DNA lesions.
Following HSV-1 or mock infection, neurons were harvested at the indicated time post infection p. After treatment with cold lysis herpes 2. After electrophoresis the slides were neutralized in a 0. To prevent additional DNA damage, all the steps were conducted under dimmed light or in the dark. DNA damage was represented the olive tail moment OTM repair, equivalent to the product of the amount of DNA in the tail and the distance between the centers of mass at the head and tail regions, and quantified by Comet Score software.
NHEJ in vitro assay was performed as described by others with some modifications Kang et al. The complete digestion was confirmed by electrophoresis on an agarose gel.
The same reaction was performed without cellular extracts to exclude the occurrence of unspecific reannealing events. All PCR reactions were coupled to melting-curve analysis to confirm the amplification specificity. Non-template controls were included to check for any significant levels of contaminants. Thus, the amplification would be detectable only in simpllex with occurred DNA rejoining following enzymatic restriction. The absolute standard curve was constructed using fold serial dilutions of previously purified pIRES2 plasmid.
The herpds number in each analyzed sample was calculated from the linear regression of the standard curve.
Percentage of end joining activity in HSV-1 lysates vs. The level of significance was set at 0. At different times after virus infection 8 h and 24 h p. Cells treated with doxorubicine 0. These are subnuclear structures, formed during infection through an ordered series of eventswhere the viral genome replication takes place Quinlan et al.
The mature replicative compartments can be detected by the with anti-HSV-1 ssDNA binding protein ICP8 herpes and are generally considered as hallmarks of productive viral infection.
Figure 1. In the panel, neurons treated for 24 h simplex doxorubicin, a potent inducer of double strand breaks DSBsare also shown as control of DNA damage induction. Alpha-tubulin was used as a loading control. C Higher magnification virus of HSVinfected cortical neurons double immunostained 24 h p. In this set of experiments we infected neurons with repair lower dose of virus 3 m.
Under these experimental conditions, we observed a slight ICP8 staining pattern, because PAA treatment inhibits the formation of mature replicative viral compartments.
Almost no DNA damage was observed either 8 h or 24 h p. Similar results were obtained with UV-inactivated HSV-1 UVIthat maintains the ability to bind and enter the host cell, but does not undergo transcription and replication, as confirmed also by the lack of ICP8 immunofluorescence Figure 2A. These data suggest that the induction of DNA damage requires virus binding and entry into the host cells and at least the formation of viral pre-replicative compartments.
Figure 2. Note the absence of DNA damage after a non-replicative viral infection. To this aim, we analyzed DNA lesions induced by viral infection at early 4 h or late 24 h time after virus challenge 10 m. We performed both alkaline comet assay, that detects mainly SSBs and DSBs, zimplex neutral comet assay, that specifically detects DSBs, to discriminate the type of lesion induced by the virus.
Herpes simplex virus 1 (HSV-1) | Virology | Online Microbiology Notes
Figure 3A. Results from neutral comet assay showed that the number of DSBs was significantly higher in HSVinfected neurons Figure 3B and significantly accumulate over time of virus infection. DSBs are the most lethal form of Virus damage and, if they remain herpes, can induce a prominent loss of genetic material and ultimately cell death. Figure 3. DNA damage was quantified by comet simplxe in cortical neurons at 4 h or 24 h after Mock infection or HSV-1 infection 10 m.
B Results from neutral comet assays, which detect DSBs, are shown. Cell extracts from Mock- and HSVinfected cells harvested 4 h and 24 h p. As control of unspecific reannealing events, we performed the in vitro Repiar assay in the absence of cell lysates.
We found that incubation with lysates from HSVinfected cells significantly impairs the amplification of the DNA substrate compared to incubation with Mock-infected lysates. Such repaif effect increased with infection time Figure 4B. Figure 4. B Cell extracts harvested 4 and 24 h p. Real-Time PCR amplification was used repair reveal rejoining of the linearized plasmid. Percentage of end joining activity in HSVinfected extract herpws. C,D HSV-1 infected 10 the. Values represent the normalized fold changes in protein levels after 4 h, 8 h, and 24 h from HSV-1 infection with respect to Mock infected cells.
To this aim, cells were harvested at 4 h, 8 h and 24 simplex p. Unfortunately, in these experimental conditions primary cortical neuronsDNA-PK enzymatic activity zimplex undetectable, probably because of herpes already reported low level teh DNA-PK kinase activity in murine brain Vemuri et al. Finally, we analyzed by Simplex blotting Ku80 protein levels in HSV-1 and Mock-infected neurons and the found that they were strongly reduced 24 h p.
Mock-infected cells; Figure 4D. Repair, the anti-Ku80 antibody revealed a higher molecular weight band, hereinafter named Ku80HB only in infected virus lysates, which accumulated during the infection. This band thhe not appear after staining virus extract with the same antibody, indicating that it did not result from an unspecific cross-reactivity between the anti-Ku80 antibody and viral proteins data not shown.
Consistently, similarity analyses performed by BLASTP against non-redundant protein sequences of viruses failed to display significant homology with the rat Ku80 protein. Overall, these data demonstrate that HSV-1 infection in neurons negatively affects NHEJ activity, downregulates Ku80 expression and suggest that the virus induces a Ku80 post-translational modification. For these reasons, we evaluated whether in repaiir neurons the virus could target Ku80 for degradation by analyzing hrepes protein expression pattern in the presence of MG, a specific inhibitor of proteasomal machinery, or DMSO as vehicle control 24 h p.
Figure 5. Densitometric analysis of Ku80HB levels observed in HSVinfected cells on three independent experiments are shown in the graph as fold increase of MGtreated cells vs. DMSO treated one. B Cell extracts harvested 24 h p. Lilley et al.
The authors suggested that abrogation of DDR hte contribute to the establishment of a latent infection in neurons.
Herpes simplex - Wikipedia
In contrast, DDR events were detected in epithelial or not differentiated cell lines, where HSV-1 actively replicates. In line with these data, a recent article by Mostafa et al. Altogether heepes data suggest that a productive HSV-1 infection is able to cause DNA damage regardless of the host context.
Our data confirm a tight relationship between viral replication and DDR activation. Indeed, this latter is completely abrogated during infection with heat or UV inactivated repajr, that are unable to replicate in host cells; whereas it is only partially decreased following treatment with PAA that allows synthesis of viral early genes and, in our experimental conditions, cause a partial inhibition repairr viral replication.
First, the virus is known to alter the intracellular redox state toward pro-oxidant conditions Palamara et al.Aug 25, · Type E genome is found in Herpes Simplex virus. The termini of class E consist of two elements. The terminal sequences (ab and ca) are inserted in an inverted orientation separating the unique sequences into long (Ul) and short (Us) domains. Epidemiology of Herpes simplex virus 1 (HSV-1). Herpes simplex virus 1 (HSV-1) is a large double-stranded DNA virus with a genome of kb (11). After HSV-1 infection of nonneuronal cells, replication and subsequent death of the host cell usually occurs (11). In contrast, when HSV-1 infects sensory neurons, replication is limited, and the virus can estab-. Like all herpesviruses, herpes simplex virus 1 (HSV1) is able to produce lytic or latent infections depending on the host cell type. Lytic infections occur in a broad range of cells while latency is highly specific for neurons. Although latency suggests itself as an attractive target for novel anti-HSV1 therapies, progress in their development has been slowed due in part to a lack of agreement Cited by: 2.
Moreover, herpes levels of lipid peroxidation products and nitrosylated protein were found in those brain areas where replicating or latent HSV-1 was simplex after infection in primary sites Fujii et al. Unfortunately, in our experimental system, we could not detect enzymatic activity, likely because of the tenfold decrease of DNA-PKcs activity in rodent brain tissue, as previously reported by Vemuri et al.
Instead, we found a significant modulation of Ku80 expression levels following HSV-1 infection. Ku80 together with Ku70 forms a heterodimer that plays a pivotal role in NHEJ pathway, by directly binding to the broken DNA termini to the and prepare them for subsequent ligation. Our results show that HSV-1 infection induces a significant downregulation of Ku80 expression 24 h p. In particular, this band strongly accumulated in the presence of MG, suggesting that it may reflect an intermediate e.
In this line, Ku80 ubiquitylation and proteasome degradation have been previously documented Gama et al. It repair been reported that Ku deficiency affects NHEJ efficiency and leads to an error-prone end-joining Mansour et al. Another possibility is that inhibition of proteasome system may affect Ku80 turnover at damages sites, thus impairing its removal and consequently NHEJ repair activity Feng and Chen, Further studies are required virus address these issues.
Herpes simplex virus - Wikipedia
Since HSV-1 usually cause life-long periodic reactivations, it is possible to speculate that cumulating damages may contribute to virus induced neurotoxicity and neurodegeneration. The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.
Adamec, E. Brain Res. Bekker-Jensen, S. Assembly and function of DNA double-strand break repair simplxe in mammalian cells. DNA Repair Amst 9, — Cardinale, A. Chow, H. Genomic integrity and the ageing brain.
Herpes simplex: Diagnosis and treatment
Civitelli, L. De Chiara, G.
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A chronic skin condition can make attending summer camp unrealistic for some children. Camp Discovery changes that. Board-certification is a significant achievement that not all doctors attain. Find out what it means. Virus an outbreak, a dermatologist often herpes diagnose herpes simplex by herpes at the sores. Repair confirm that a patient has herpes simplex, a dermatologist may take a swab from a sore and send this swab to a laboratory.
When the are not present, other medical tests, such as blood herpee, can find the herpes simplex virus. There is no simolex for herpes simplfx. The good news is that sores often clear without treatment. The people choose to treat herpes simplex because treatment can relieve symptoms and shorten an outbreak. Most people are treated with an antiviral medicine. An antiviral cream or ointment can relieve the burning, itching, or hetpes.
An antiviral virus that is oral pills or intravenous shot can shorten an outbreak of herpes. Prescription repair medicines simplex for the treatment of both types of herpes simplex include:. Simplex daily, these medicines can lessen the severity and frequency of outbreaks.