# Comparative Transcriptomic Analysis Reveals Divergent Host Cell Responses to Classical and Variant Pseudorabies Virus Strains

## TL;DR

This study compares how classical and variant pseudorabies virus strains affect host cells, finding that the variant strain causes more severe changes in gene activity and may pose a greater health risk.

## Contribution

The study identifies PCNA and CYP1A1 as key host factors in variant PRV infection and highlights their potential as antiviral targets.

## Key findings

- The variant PRV (WH) strain shows higher infectivity in cells and mice compared to the classical MinA strain.
- Transcriptomic analysis reveals that WH infection alters host gene expression, particularly in cell cycle and immune response pathways.
- Pharmacological inhibition of PCNA and CYP1A1 reduces PRV infection, indicating their role in the viral process.

## Abstract

The objective of this study was to compare the biological characteristics of the classical and variant pseudorabies virus (PRV) in vitro and in vivo. The results showed that the variant PRV (WH) strain exhibits enhanced infectivity in 3D4/21 cells and murine models compared to the classical MinA strain. Transcriptomic analysis revealed that infection with the WH strain induces significant alterations in host cell gene expression at 12 h post-infection, with differentially expressed genes predominantly associated with the cell cycle and immune response pathways. Notably, the genes PCNA and CYP1A1 were upregulated following infection, and pharmacological inhibition of these genes effectively attenuated PRV infection. These findings suggest that the mutated PRV strain may represent an increased threat to human health. Furthermore, the identification of PCNA and CYP1A1 as critical host factors in the viral infection process offers promising targets for the development of novel antiviral interventions.

Classical and variant strains of pseudorabies virus (PRV, also called suid alphaherpesvirus 1) have been concurrently prevalent in China, with recent studies indicating that variant PRV strains may possess zoonotic potential, thereby representing a possible threat to human health. Despite this, the comparative transcriptomic responses of host cells by classical and variant PRV strains have not been thoroughly investigated. In this study, we conducted in vitro and in vivo experiments to compare the biological characteristics of the classical MinA strain and the variant WH strain. Moreover, we performed a comprehensive gene expression profiling of porcine alveolar macrophage cells (3D4/21) infected with the WH strain at 12 h post-infection, relative to those infected with the MinA strain. Our findings demonstrated that both 3D4/21 cells and Kunming mice exhibited increased susceptibility to the WH strain compared to the MinA strain. Transcriptomic analysis identified 569 significantly upregulated genes and 1091 significantly downregulated genes in WH-infected cells relative to uninfected controls, whereas MinA-infected cells showed 343 upregulated and 515 downregulated genes. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses revealed that the most prominent differentially expressed genes (DEGs) were predominantly associated with cell cycle regulation, DNA replication and immune response pathways. Notably, the genes PCNA and CYP1A1 were involved in these pathways; both of them were upregulated after PRV infection. Further investigation demonstrated that pharmacological inhibition of CYP1A1 and PCNA effectively suppressed PRV infection, suggesting their involvement in the viral infection process. Nonetheless, the precise mechanisms underlying their roles warrant further elucidation. In summary, this study provides comparative evidence for the heightened threat posed by variant PRV strains and identifies PCNA and CYP1A1 as key host–cell factors involved in the infection process, offering new potential targets for antiviral strategies against this economically significant pathogen.