Neuronal cytoskeletal dynamic modification and neurodegeneration induced by infection with herpes simplex virus type 1.

Herpes simplex virus type 1 (HSV-1) and herpes simplex virus type 2 (HSV-2) belong to the family Herpesviridae, the subfamily Alphaherpesvirinae, and the genus Simplexvirus. They are ubiquitous, neurotropic, and the most common pathogenic cause of sporadic acute encephalitis in humans. Herpes simplex encephalitis (HSE) is associated with a high mortality rate and significant neurological, neuropsychological, and neurobehavioral sequelae, which afflict patients for life. HSV-1 has been suggested as an environmental risk factor for Alzheimer's disease. However, the mechanisms involved in HSV-1 infection that may trigger the neurodegenerative process are still unknown. In general, HSV-1 induced cytoskeletal alterations reported to date involve the overall disruption of one or more elements of the cytoskeleton in cell lines. Axonal injury has recently attracted attention as a key predictor for the outcome of a number of brain disorders. Here we show that infection of mice neuronal cultures with HSV-1 result in marked neurite damage and neuronal death. Furthermore, in this in vitro model of infection, neurons manifested considerable alterations in microtubule dynamics and tau hyperphosphorylation. These results suggest a possible link between HSV-1 infection and neuronal cytoskeletal disruption.