Klouser, L. M. | Search bioRxiv

bioRxiv2023

Viral gene drive spread during herpes simplex virus 1 infection in mice

Gene drives are genetic modifications designed to propagate efficiently through a population. Most applications rely on homologous recombination during sexual reproduction in diploid organisms such as insects, but we recently developed a gene drive in herpesviruses that relies on co-infection of cells by wild-type and engineered viruses. Here, we developed a viral gene drive against human herpes simplex virus 1 (HSV-1) and showed that it propagated efficiently in vitro and during HSV-1 infection in mice. We observed high levels of co-infection and gene drive-mediated recombination in neuronal tissues during herpes encephalitis as the infection progressed from the site of inoculation to the peripheral and central nervous systems. In addition, we found evidence that a superinfecting gene drive virus could recombine with wild-type viruses during latent infection. These findings indicated that HSV-1 achieves high rates of co-infection and recombination during viral infection, a phenomenon that is currently underappreciated. Overall, this study showed that a viral gene drive could spread in vivo during HSV-1 infection, paving the way toward therapeutic applications.

microbiology↗

bioRxiv2022

AAV-delivered gene editing for latent genital or orofacial herpes simplex virus infection reduces ganglionic viral load and minimizes subsequent viral shedding in mice

Herpes simplex virus (HSV) establishes latency in ganglionic neurons of the peripheral nervous system, from which it can reactivate, causing recurrent disease and possible transmission to a new host. Current anti-HSV therapy does not eliminate latent HSV, and thus is only suppressive rather than curative. We developed a potentially curative approach to latent HSV infection and pathogenesis, based on gene editing using HSV-specific meganucleases delivered by adeno-associated virus (AAV) vectors. Our results demonstrated that a dual meganuclease therapy, composed of two anti-HSV-1 meganucleases delivered by a triple AAV serotype combination (AAV9, AAV-Dj/8, AAV-Rh10), can eliminate up to 97% of latent HSV DNA from ganglia in both ocular and vaginal mouse models of latent HSV infection. Using a novel pharmacological approach to reactivate latent HSV-1 in mice with the bromodomain inhibitor JQ-1, we demonstrated that this reduction in ganglionic viral load leads to a significant reduction of viral shedding from treated vs. control mice, with many treated mice showing no detectable virus shedding. In general, therapy was well tolerated, although dose-ranging studies showed hepatotoxicity at high AAV doses, consistent with previous observations in animals and humans. Also in agreement with previous literature, we observed subtle histological evidence of neuronal injury in some experimental mice, although none of the mice demonstrated observable neurological signs or deficits. These results reinforce the curative potential of gene editing for latent orofacial and genital HSV disease, and provide a framework for additional safety studies before human trials can begin.

neuroscience↗