Efficacy of HSV1-specific meganucleases in a mouse model of relapsing herpes keratitis

Abstract

Purpose: While conventional drugs used in the treatment of infections by Herpes simplex virus type 1 (HSV1) does not reduce the burden of latent virus and therefore the risk of viral reactivation, specific endonucleases (such as méganucléases) could be an issue to reduce the relapsing herpetic keratitis in previously treated tissues.

Methods: Three weeks after subconjunctival inoculation of rAAV (recombinant adenovirus-associated) encoding a meganuclease specific to HSV1 (or the Green Fluorescent Protein, GFP), mice were infected in the lip with a wild type strain of HSV1 (SC16) to induce a latent infection in the trigeminal ganglia (TGs) TG. After 28 days, mice were subjected to a reactivation stimulus (heatshock) and then sacrificed. Corneas and TGs were analyzed for the presence of HSV-1 genome and several viral transcripts (LAT, TK and UL18).

Results: In the corneas, as in TG, mice treated with rAAV encoding meganuclease had more copies of viral genomes (viral load) and LAT, TK and UL18 transcripts (signs of viral replication) that control mice, ie treated with rAAV encoding GFP (p = 0.002 to p = 0.0008), suggesting a significant reduction in the activity of viral replication after herpes reactivation stimulus.

Conclusions: The subconjunctival inoculation of rAAV encoding a specific HSV1 meganuclease in ocular tissues seems to reduce the importance of HSV1 reactivation in TGs (the site of herpetic latency) and corneas. These results suggest that specific HSV1 meganuclease could be tested in therapeutic protocols with the aim of reducing the risk of herpes reactivation in the cornea.

Keywords: 545 herpes simplex virus • 573 keratitis • 425 antiviral drugs