Neuropathogenic and non-neuropathogenic EHV-1 strains induce the accumulation of hyperphosphorylated Tau in primary murine neurons.

Equid herpesvirus 1 (EHV-1) causes respiratory disease, abortion and neurological disorders in horses. Similarly, to other alphaherpesviruses, EHV-1 is neurotropic and establishes latency in the neurons of its natural host. Despite the fact that many studies have been devoted to the pathogenesis of various clinical forms of EHV-1 infection, mechanisms of the neuronal damage are still not fully understood. The aim of this study was to define the phosphorylation status of tau protein in neuronal cell culture infected with EHV-1. Phosphorylation of tau was tested at tau-ser199/ser202, tau-ser404, tau-ser262, tau-thr181, tau-thr217 and tau-thr205 sites. We described, for the first time, that EHV-1 infection leads to the accumulation of hyperphosphorylated tau in primary murine neurons. We showed that non-neuropathogenic and neuropathogenic EHV-1 strains specifically induce hyperphosphorylation of tau-ser199/ser202, tau-ser404 and tau-thr205 during long-term infection and after a controlled activation of productive infection. Keywords: tau protein; hyperphosphorylation; equid herpesvirus 1 (EHV-1); neuronal cell culture.