Author ORCID Identifier
https://orcid.org/0000-0002-2269-773X
Date of Award
2025
Document Type
Thesis (Ph.D.)
Department or Program
Microbiology and Immunology
First Advisor
David A. Leib
Abstract
Herpes simplex virus 1 (HSV-1) establishes latent infections in sensory neurons, from which HSV sporadically reactivates, often due to external stress and other stimuli. Latency and reactivation are commonly studied using in vivo and ex vivo models in a variety of hosts, as well as in vitro models including primary mouse neurons and neurons derived from human pluripotent stem cells (iPSCs). The criteria for authentically modeling HSV latency include the ability to easily manipulate host genetics and biological pathways, as well as mimicking the immune response and viral pathogenesis in human infections. Presently, there remains a pressing need for models that more closely recapitulate human HSV infection. To address this, we used human iPSCs that have been genetically modified to rapidly differentiate into sensory neurons (iNeurons) as a model to study the mechanisms that regulate acute and latent HSV-1 infection.
The interferon (IFN)-based neuronal innate immune response is critical in controlling HSV-1 replication and HSV-1 counters these responses, in part, through infected-cell protein 34.5 (ICP34.5). ICP34.5 also promotes neurovirulence by preventing host translational shutoff and interfering with host cell autophagy through its interaction with the autophagy regulator Beclin 1. Here we demonstrate in iNeurons that ICP34.5 unexpectedly suppresses spontaneous reactivation and thereby is critical for maintenance of HSV-1 latency. Furthermore, our results suggest that both sustaining host translation and the interaction of ICP34.5 with Beclin 1 are important for maintaining latency in iNeurons. Experiments using primary mouse neurons show that ICP34.5 may be essential for maintaining latency but in an IRF3/7-dependent manner. In wild type mouse neurons, ICP34.5-null and ΔPP1⍺ viruses exhibited little spontaneous reactivation and had defects in induced reactivation suggesting that countering PKR-mediated responses is the key activity of ICP34.5 for enhancement of reactivation. These results highlight the value of studying HSV-1 latency and reactivation in different models and we explore explanations for how ICP34.5 may differentially impact latency in the two systems studied herein.
Recommended Citation
Canova, Paige N., "Of Mice and Men: The Regulation of Herpes Simplex Virus 1 Latency in Mouse and Human Neurons" (2025). Dartmouth College Ph.D Dissertations. 366.
https://digitalcommons.dartmouth.edu/dissertations/366
