There exists a great need for the modeling of axonal transport and persistence of the human herpesvirus Varicella zoster Virus in neurons. The sensory neuron is critical to successful VZV pathogenesis as it is the site of a decades-long state of persistence, from which VZV can reactivate to cause the debilitating disease Herpes zoster. VZV remains a major source of human morbidity, even in an age of commercial vaccines, as most adults harbor wild type VZV strains and some 1/5 will suffer zoster (""""""""shingles""""""""). Zoster morbidity includes a subsequent chronic intractable neuropathic pain state that can affect quality of life and is often refractory to any treatment. Even if all eligible persns received the zoster vaccine (which is far from being achieved);the partial effectiveness would still result upwards of half as million zoster cases annually and some 50,000 cases of severe post herpetic neuralgia. We know little of the parameters affecting VZV axonal transport and the latent state, because most animal models and their neurological tissues do not support VZV replication or reactivation. Yet, if axonal transport, latency or the interneuronal spread associated with zoster can be prevented, disease could more easily be controlled. Our overlying hypothesis is that we can explore VZV axonal transport and persistence using an innovative system involving peripheral neurons developed from human embryonic stem cells (hESC). We have partly established this system and shown VZV axonal infection and neuron to neuron spread. The first specific aim is to use hESC derived neurons in microfluidic chambers to examine retrograde and anteriograde transport kinetics of VZV capsids and the association of known VZV tegument regulatory proteins with the transporting capsid, using live cell imaging of fluorescent VZV capsids in axons, which has never been previously described.
Specific Aim 2 will test the hypothesis that axonal transport and/or interneuronal spread can be disrupted by specific VZV gene deletions. As yet we know little of the VZV proteins involved in VZV transport.
The third aim i s to develop the hESC neurons to model VZV persistence, the events of latency, and to attempt to reactivate persistent VZV genomes, which heretofore has arguably never been achieved.
Varicella zoster virus causes chickenpox, the disfiguring disease shingles and intractable, difficult to treat chronic pain. This proposal uses a simplified cultured human neuron system, developed from human embryonic stem cells, to examine the unexplored areas of transport of the virus to the neuron and the establishment of a state of persistence. These mirror events that occur in humans following chickenpox, and are key steps that can be therapeutically targeted to prevent the debilitating disease Herpes zoster (Shingles) and the intractable chronic pain that often follows.
