To determine whether herpes simplex virus type 1 (HSV-1) infection causes oxidative stress and lipid peroxidation in cultured neural cells, mouse P19 embryonal carcinoma cells were differentiated into cells with neural phenotypes (P19N cells) by retinoic acid and were then infected with HSV-1. Cellular levels of reactive oxygen species (ROS) and the release of lipid peroxidation by-products into the tissue culture medium were then measured by the generation of fluorescent markers hydroxyphenyl fluorescein and a stable chromophore produced by lipid peroxidation products, malondialdehyde (MDA) and hydroxyalkenals (4-HAEs; predominantly 4-hydroxy-2-nonenal [HNE]), respectively. HSV-1 infection increased ROS levels in neural cells as early as 1 h post infection (p.i.) and ROS levels remained elevated at 24 h p.i. This viral effect required viral entry and replication as heat- and ultraviolet light-inactivated HSV-1 were ineffective. HSV-1 infection also was associated with increased levels of MDA/HAE in the culture medium at 2 and 4 h p.i., but MDA/HAE levels were not different from those detected in mock infected control cultures at 1, 6, and 24 h p.i. HSV-1 replication in P19N cells was inhibited by the antioxidant compound ebselen and high concentrations of HNE added to the cultures, but was increased by low concentrations of HNE. These findings indicate that HSV-1 infection of neural cells causes oxidative stress that is required for efficient viral replication. Furthermore, these observations raise the possibility that soluble, bioactive lipid peroxidation by-products generated in infected neural cells may be important regulators of HSV-1 pathogenesis in the nervous system.

HSV-1 entry into HCjE cells is a pH-dependent process that is aided by targeted virus travel on filopodia. HCjE cells express all three major entry receptors, with nectin-1 and HVEM playing the predominant role in mediating entry.

To better understand melanoma resistance to herpes simplex virus type 1 (HSV-1)-mediated oncolysis, traditional two-dimensional (2D) cultures and extracellular matrix (ECM) containing three-dimensional (3D) cultures of OCM1 and C918 uveal melanoma cells were infected with an HSV-1 strain that expresses the green fluorescent protein (GFP) marker during replication. Although 2D cultures were completely destroyed within a few days of HSV-1 inoculation, viable GFP-negative tumor cells remained detectable in 3D cultures for several weeks. Tumor cells with increased resistance to HSV-1 included cells that formed vasculogenic mimicry patterns and multicellular spheroids and cells that invaded Matrigel individually. Mechanisms of tumor resistance against HSV-1 in the 3D environment included impaired virus spread in the ECM and ECM-mediated inhibition of viral replication after viral entry into tumor cells. Observations also suggested that HSV-1 established quiescent infection in some tumor cells present in multicellular spheroids and that this could revert to productive viral infection when the tumor growth pattern changed. These findings indicate that 3D tumor cell cultures can be used to identify distinct tumor cell populations with increased resistance to HSV-1 and to explore mechanisms of ECM-mediated tumor resistance to oncolytic virotherapy.

Multiple Sclerosis (MS) is a chronic disease, but in rare fulminant cases rapid progression may lead to death shortly after diagnosis. Currently there is no diagnostic test to predict disease course. The aim of this study was to identify potential biomarkers/proteins related to rapid progression. We present the case history of a 15-year-old male MS patient. Cerebrospinal fluid (CSF) was taken at diagnosis and at the time of rapid progression leading to the patient’s death. Using isobaric tag labeling and nanoflow liquid chromatography in conjunction with matrix assisted laser desorption/ionization time of flight tandem mass spectrometry we quantitatively analyzed the protein content of two CSF samples from the patient with fulminant MS as well as one relapsing-remitting (RR) MS patient and one control headache patient, whose CSF analysis was normal. Seventy-eight proteins were identified and seven proteins were found to be more abundant in both fulminant MS samples but not in the RR MS sample compared to the control. These proteins are involved in the immune response, blood coagulation, cell proliferation and cell adhesion. In conclusion, in this pilot study we were able to show differences in the CSF proteome of a rapidly progressing MS patient compared to a more typical clinical form of MS and a control subject.

HVEM is expressed in the cornea and TG and therefore may serve as an HSV entry receptor in these tissues. Furthermore, these findings raise the possibility that changes in HVEM expression following ocular HSV-1 infection can modulate HSV spread and infection-induced inflammation in the cornea and TG.

Herpes simplex viruses (HSV) produce age-dependent encephalitis characterized by more severe involvement of the cerebral cortex in younger hosts. To elucidate the potential role of the major neural entry receptor of HSV, nectin-1, in age-dependent susceptibility of cortical neurons to viral encephalitis, the authors examined the anatomical distribution of the receptor protein in the developing human and mouse cerebral cortex, hippocampus, and cerebellum by immunohistochemistry. Nectin-1 is expressed at high levels in guiding cells (radial glial cells and Cajal-Retzius cells) that regulate radial migration of neurons in cortical lamination, at lower levels in migrating neurons, and at variable levels in the transient ventricular and marginal zones of the cerebral cortical wall. These results may have implications regarding the selective spatiotemporal tropism of HSV to specific neuronal populations, and for the better understanding of neurodevelopmental defects caused by fetal HSV infections.

Numerous epidemiological studies have proposed a link between herpes simplex virus (HSV) infection and several common chronic neuropsychiatric and neurodegenerative diseases. Experimental HSV infection of mice can lead to chronic behavioral and neurological deficits and chronic pain. While neuron injury and loss are well documented consequences of the acute phase of infection, the pathologic consequences of latent HSV infection are poorly understood. To determine whether latent HSV infection can cause neuronal injury in mice, trigeminal ganglia (TG) derived from adult BALB/c mice 1, 12, and 31 weeks after corneal herpes simplex virus type 1 (HSV-1) inoculation were analyzed for evidence of productive or latent HSV-1 infection, inflammation, and changes in neuron size, density, and number. We found that latent HSV-1 infection between 12 and 31 weeks after corneal virus inoculation was associated with inflammation and progressive deficits in mean neuron diameter, neuronal nucleus diameter, neuron density, and neuron number in the TG relative to mock-infected controls. The extent of neuronal injury during latent infection correlated with the extent of inflammation. These studies demonstrate that latent HSV infection is associated with progressive neuronal pathology and may lead to a better understanding of the role of HSV infections in chronic neurological diseases.

No abstract