Poliovirus replication and spread in primary neuron cultures

AbstractWhile some neurotropic viruses cause rapid central nervous system (CNS) disease upon entry into the brain parenchyma, other viruses that are cytolytic in the periphery either result in little neuropathology or are associated with a protracted course of CNS disease consistent with persistent infection. One such virus, poliovirus (PV), is an extremely lytic RNA virus that requires the expression of CD155, the poliovirus receptor (PVR), for infection. To compare the kinetics of PV infection in neuronal and non-neuronal cell types, primary hippocampal neurons and fibroblasts were isolated from CD155+ transgenic embryos and infected with the Mahoney and Sabin strains of PV. Despite similar levels of infection in these ex vivo cultures, PV-infected neurons produced 100-fold fewer infectious particles as compared to fibroblasts throughout infection, and death of PV-infected neurons was delayed approximately 48 h. Spread in neurons occurred primarily by trans-synaptic transmission and was CD155-dependent. Together, these results demonstrate that the magnitude and speed with which PV replication, spread, and subsequent cell death occur in neurons is decreased as compared to non-neuronal cells, implicating cell-specific effects on replication that may then influence viral pathogenesis

Neurokinin-1 enables measles virus trans-synaptic spread in neurons

AbstractMeasles virus (MV), a morbillivirus that remains a significant human pathogen, can infect the central nervous system, resulting in rare but often fatal diseases, such as subacute sclerosing panencephalitis. Previous work demonstrated that MV was transmitted trans-synaptically and that, while a cellular receptor for the hemagglutinin (H) protein was required for MV entry, it was dispensable for subsequent cell-to-cell spread. Here, we explored what role the other envelope protein, fusion (F), played in trans-synaptic transport. We made the following observations: (1) MV-F expression in infected neurons was similar to that seen in infected fibroblasts; (2) fusion inhibitory peptide (FIP), an inhibitor of MV fusion, prevented both infection and spread in primary neurons; (3) Substance P, a neurotransmitter with the same active site as FIP, also blocked neuronal MV spread; and (4) both genetic deletion and pharmacological inhibition of the Substance P receptor, neurokinin-1 (NK-1), reduced infection of susceptible mice. Together, these data implicate a role for NK-1 in MV CNS infection and spread, perhaps serving as an MV-F receptor or co-receptor on neurons