Pseudorabies viral replication is inhibited by a novel target of miR-21

The pseudorabies virus (PRV) is a porcine virus classified as a member of the Alphaherpesvirinae subfamily of Herpesviridae. Recent studies have confirmed that viruses regulate the gene expression in host cells. Commonly affected genes include oxidative-stress response genes, genes involved in the phosphatidylinositol 3-kinase/Protein Kinase B (PI3K/Akt) signaling pathway, and interferon- and interleukin-related genes. However, the post-transcriptional regulation of host genes following PRV infection is hitherto unclear. In this study, we used miRNA microarray approaches to assess miRNA expression in PRV-infected porcine kidney 15 cell line (PK-15), and observed that miR-21 was expressed at high level 12 h after the cells were infected with PRV. Furthermore, we identified chemokine (C-X-C motif) ligand 10 (CXCL10), also named interferon-γ inducible protein-10 (IP-10), as a novel target gene of miR-21. IP-10 was down-regulated at 4 h after PRV infection. PRV replication was significantly inhibited by IP-10 overexpression.