trichostatin-a and Herpes-Simplex

Myriocin is a fungal metabolite with antiviral activity, including influenza, hepatitis B, and hepatitis C viruses. We investigated whether myriocin has activity against human HSV-2, one of the most prevalent pathogens of sexually transmitted disease.. Cell culture systems were used to evaluate myriocin effect on HSV-2 infection. Plaque forming assay and immunoblotting studies were used to determine virus production and viral protein expression, respectively.. Myriocin showed no cytotoxic effect at up to 5 μM. Myriocin treatment did not inhibit HSV-2 infection. Instead, the treatment resulted in accelerated replication of HSV-2 and increased titers of infectious virion. The effect was detected at concentrations as low as 3 nM and plateaued at approximately 30 nM. Myriocin at 30 nM increased HSV-2 production by approximately 1.7 logs. Myriocin also promoted HSV-1 infection but required higher concentrations. A time course study revealed that myriocin promoted HSV-2 infection by acceleration of virus replication. Unlike trichostatin A that promotes HSV-2 infection and histone modifications, myriocin treatment did not alter histone modifications. Myriocin is a well characterized inhibitor of sphingolipid biosynthesis pathway. Structurally different inhibitors of the pathway showed no effect on HSV-2 infection. Exogenous sphingolipids did not reverse the effect of myriocin on HSV-2 infection either.. We found that myriocin promotes HSV-2 replication at nanomolar concentrations with yet unknown mechanisms. Further studies may uncover novel mechanisms regulating HSV replication and targets of myriocin action. This may have potential application in enhancing efficacy of oncolytic HSV for cancer therapy and other diseases.

Topics: Animals; Antiviral Agents; Cell Line, Tumor; Chlorocebus aethiops; Disease Progression; Dose-Response Relationship, Drug; Fatty Acids, Monounsaturated; Herpes Simplex; Herpesvirus 2, Human; Histones; Humans; Hydroxamic Acids; Sphingolipids; Vero Cells; Virus Replication

Intrinsic differences in neurons of the vestibular ganglia result in the increased likelihood of superior vestibular ganglion involvement in vestibular neuritis.. Vestibular neuritis is hypothesized to result from herpes simplex type I (HSV1) infection or reactivation in vestibular ganglia. Involvement of the inferior vestibular ganglion is extremely rare in patients with vestibular neuritis.. Primary cultures of rat superior and inferior vestibular ganglion neurons (VGNs) were cultivated separately. Neurons were lytically and latently infected with HSV1 with a US11-green fluorescent protein (GFP) chimera. Percentage lytic infection and baseline reactivation was assessed by microscopy for GFP fluorescence. Trichostatin-A (TSA) was used to stimulate HSV1 reactivation. Virion production was assessed by viral titers. Relative numbers of latency-associated (LAT) transcripts were determined by real-time reverse-transcription polymerase chain reaction (real-time RT-PCR).. Lytic infection rates were equivalent between the two ganglia (p > 0.05). Lytic infections yielded similar amounts of plaque-forming units (p > 0.05). Relative amounts of LAT transcripts did not differ between latently infected superior and inferior VGNs. Latently infected cultures showed no differences in rates of baseline and TSA-induced HSV1 reactivation (p > 0.05). Production of virions was not significantly different between reactivated, latently infected superior versus inferior VGNs (p = 0.45).. Differences in prevalence of superior and inferior vestibular neuritis do not result from intrinsic differences in HSV1 infection or virion production of these neurons. Other factors, such as the length and width of the bony canal containing the ganglia and nerves, account for the greater involvement of the superior vestibular ganglion in vestibular neuritis.

Topics: Animals; Chimera; Female; Ganglia; Green Fluorescent Proteins; Herpes Simplex; Herpesvirus 1, Human; Hydroxamic Acids; Male; Neurons; Polymerase Chain Reaction; Rats; Rats, Sprague-Dawley; Vestibular Nerve; Vestibular Neuronitis; Vestibule, Labyrinth; Virus Activation; Virus Latency

Histone acetylation is implicated in the regulation of herpes simplex virus type 1 (HSV-1) latency. However, the role of histone acetylation in HSV-1 reactivation is less clear. In this study, the well-established model system, quiescently infected, neuronally differentiated PC12 (QIF-PC12) cells, was used to address the participation of histone acetylation in HSV-1 reactivation. In this model, sodium butyrate and trichostatin A (TSA), two histone deacetylase inhibitors, stimulated production of infectious HSV-1 progeny from a quiescent state. To identify viral genes responsive to TSA, the authors analyzed representative alpha, beta, and gamma viral genes using quantitative real-time polymerase chain reaction. Only the latency-associated transcript (LAT) accumulated in response to TSA treatment, under culture conditions that restricted virus replication and spread. This led the authors to evaluate the importance of LAT expression on TSA-induced reactivation. In QIF-PC12 cells, the LAT deletion mutant virus dLAT2903 reactivated equivalently with its wild-type parental strain (McKrae) after TSA treatment, as well as forskolin and heat stress treatment. Both viruses also reactivated equivalently from latently infected trigeminal ganglia explants from rabbits. In contrast, there was a marked reduction in the recovery of dLAT2903, as compared to wild-type virus, from the eyes of latently infected rabbits following epinephrine iontophoresis. These combined in vitro, ex vivo, and in vivo data suggest that LAT is not required for reactivation from latently infected neuronal cells per se, but may enhance processes that allow for the arrival of virus at, or close to, the site of original inoculation (i.e., recrudescence).

Topics: Animals; Butyrates; Coculture Techniques; Cornea; Herpes Simplex; Herpesvirus 1, Human; Histone Deacetylase Inhibitors; Histone Deacetylases; Hydroxamic Acids; MicroRNAs; PC12 Cells; Rabbits; Rats; Trigeminal Ganglion; Viral Proteins; Virus Activation