Investigating the impact of Herpes simplex virus type 1 latency-associated non-coding RNAs on apoptosis in human neuronal cells

Abstract

Herpes simplex virus 1 (HSV-1) establishes latency in sensory neurons, allowing it to persist for the lifetime of the host. During latency, the only abundantly transcribed HSV-1 gene is the latency-associated transcript (LAT), which is processed into the 2.0 kb major LAT intron and several microRNAs. These non-coding RNAs (ncRNAs) have been reported to influence latency, possibly through limiting apoptosis of infected cells. As these studies have used animal models or non-neuronal cell culture, we have developed a differentiated human neuroblastoma (SH-SY5Y cells) model to examine their effect in human neuronal cells. We have infected these neuronal cultures with replication-defective HSV-1, which establishes a quiescent infection and strongly expresses the latency ncRNAs. We show that quiescent HSV-1 infection reproducibly protects differentiated SH-SY5Y from etoposide-induced apoptosis. We are also further defining the contribution of different LAT ncRNAs using recombinant lentiviruses to drive expression of the LAT intron or microRNAs. Furthermore, we are also currently exploring the mechanisms of this anti-apoptosis effect, and broader virus-neuron interactions by characterising whether the human neuronal transcriptome is altered by LAT RNA expression. Improving our understanding of the molecular interactions underpinning HSV-1 latency in neurons could help develop novel therapies to target HSV-1 latency.