# D-glucose uptake inhibits bovine alphaherpesvirus 1 post-binding cell process entry via inhibition of PLC-γ1 signaling in a glucose transporter 1-independent manner

## TL;DR

D-glucose blocks bovine alphaherpesvirus 1 entry into cells by inhibiting a specific signaling pathway, independent of how glucose is transported into the cell.

## Contribution

This study is the first to show that D-glucose inhibits BoAHV-1 entry via PLC-γ1 signaling in a GLUT1-independent manner.

## Key findings

- D-glucose inhibits BoAHV-1 post-binding cell entry by blocking PLC-γ1 signaling.
- GLUT1 promotes viral infection by activating β-catenin signaling, but D-glucose's effects are independent of GLUT1.
- D-glucose and a PLC-γ1 inhibitor work together to synergistically block virus entry.

## Abstract

Bovine alphaherpesvirus 1 (BoAHV-1) is one of the most important viral pathogens responsible for severe economic losses in the cattle industry worldwide. We have previously shown that both phospholipase C gamma1 (PLC-γ1) and β-catenin signaling pathways play crucial roles in BoAHV-1 productive infection. In this study, we demonstrated that BoAHV-1 productive infection in bovine kidney (MDBK) cells and in bovine trigeminal ganglia neurons led to alteration of the protein expression and/or its subcellular localization glucose transporter 1 (GLUT1). In turn, GLUT1 signaling appeared to promote virus productive infection, partially by activating β-catenin-dependent transcriptional activity, as determined using GLUT1-specific small interfering RNAs or the GLUT1-specific inhibitor, BAY-876. Interestingly, D-glucose inhibited the virus post-binding cell entry process, partially through blocking PLC-γ1 signaling. Although GLUT1 is a key glucose transporter, the inhibitory effects of D-glucose on viral entry were independent of GLUT1. Moreover, we showed that D-glucose and the PLC-γ1-specific inhibitor U73122 synergistically inhibited virus cell entry. Collectively, for the first time, we revealed that D-glucose and its potential transporter GLUT1 had opposite effects on BoAHV-1 productive infection (inhibition vs promotion) via manipulation of different cell signaling pathways (PLC-γ1 vs β-catenin). These findings provide novel insights into the mechanisms underlying BoAHV-1 infection involving GLUT1 and glucose and highlight potential therapeutic targets for the development of antiviral strategies.

Virus entry is a complex process that involves the binding of viral glycoproteins to host cell receptors, and various host factors can influence this process. Here, for the first time, we found that D-glucose has the potential to block bovine alphaherpesvirus 1 (BoAHV-1) post-binding cell entry process, possibly through the inactivation of PLC-γ1 signaling. Interestingly, D-glucose regulated PLC-γ1 signaling with a GLUT1-independent mechanism, though D-glucose uptake was partially mediated by GLUT1. We also identified that β-catenin acts as a potential downstream target of GLUT1, which may represent a mechanism regarding how GLUT1 signaling contributes to BoAHV-1 productive infection. Moreover, a distinct GLUT1 staining in the pre-nuclear regions, likely corresponding to the nuclear membrane, was exclusively observed in trigeminal ganglia neurons of latently infected calves, indicating that it is also potentially involved in the virus latency, which deserves further clarification in future studies.