Fast anterograde transport of Herpes Simplex Virus: Role for the amyloid precursor protein of Alzheimer's disease

Abstract

SummaryAnterograde transport of herpes simplex virus (HSV) from its site of synthesis in the neuronal cell body out the neuronal process to the mucosal membrane is crucial for transmission of the virus from one person to another, yet the molecular mechanism is not known. By injecting GFP-labeled HSV into the giant axon of the squid, we reconstitute fast anterograde transport of human HSV and use this as an assay to uncover the underlying molecular mechanism. HSV travels by fast axonal transport at velocities four-fold faster (0.9 µ µ µ µ m/sec average, 1.2 µ µ µ µ m/sec maximal) than that of mitochondria moving in the same axon (0.2 µ µ µ µ m/sec) and ten-fold faster than negatively charged beads (0.08 µ µ µ µ m/sec). Transport of HSV utilizes cellular transport mechanisms because it appears to be driven from inside cellular membranes as revealed by negative stain electron microscopy and by the association of TGN46, a component of the cellular secretory pathway, with GFP-labeled viral particles. Finally, we show that amyloid precursor protein (APP), a putative receptor for the microtubule motor, kinesin, is a major component of viral particles, at least as abundant as any viral encoded protein, while another putative motor receptor, JIP 1/2, is not detected. Conventional kinesin is also associated with viral particles. This work links fast anterograde transport of the common pathogen, HSV, with the neurodegenerative Alzheimer's disease. This novel connection should prompt new ideas for treatment and prevention strategies.

Transport and egress of herpes simplex virus in neurons

“…In this case, pUS11 would not be accessible to kinesin and most likely a kinesin-cellular receptor or viral glycoprotein cytoplasmic tail would be required for transport. This is supported by a recent study which showed KIF5B associated with enveloped HSV-1 also containing the known kinesin cellular receptor, amyloid precursor protein (APP) [121]. Furthermore, pUS11 is not conserved across the closely related alphaherpesviruses, implying that other viral tegument/capsid proteins are recruited for axonal transport of unenveloped capsids.…”

A peptide zipcode sufficient for anterograde transport within amyloid precursor protein

“…The activity of the APP-C peptide paralleled the activity of C99, a polypeptide containing the complete cytoplasmic domain. C99 also mediated transport of beads when conjugated to beads at molar amounts equivalent to that associated with motile HSV (3,000 copies of APP per particle) (6). Truncation of the terminal 15 aa removes transport capability.…”

“…Intracellular pathogens, such as herpes simplex virus (HSV), appear to coopt this cellular transport machinery (1)(2)(3)(4)(5) and thus may serve as tools to uncover the mechanisms governing cargo-motor interactions (5,6). HSV, a neurotropic virus that causes the recurrent cold sore, travels back and forth within neuronal processes at different stages in its life cycle (7).…”

“…Upon reactivation, newly synthesized viral particles are packaged in the cell body and then travel out to the periphery by fast axonal transport within neuronal processes (1)(2)(3)(8)(9)(10). Recently we reconstituted HSV transport in the giant axon of the squid in both directions [retrograde, as detergent-stripped particles (11), and anterograde (6)] by injecting GFP-labeled virus into the giant axon of the squid. Viral particles transported in the anterograde direction were associated with a high copy number (Ϸ3,000 molecules per virion) of amyloid precursor protein (APP) (6).…”

“…Recently we reconstituted HSV transport in the giant axon of the squid in both directions [retrograde, as detergent-stripped particles (11), and anterograde (6)] by injecting GFP-labeled virus into the giant axon of the squid. Viral particles transported in the anterograde direction were associated with a high copy number (Ϸ3,000 molecules per virion) of amyloid precursor protein (APP) (6). Because APP has been implicated as a motor receptor for transport in other systems (12)(13)(14), we became interested in whether APP might play a role in anterograde transport of virus.…”