MicroRNA-4331-5p promotes FMDV replication through inhibiting interferon pathways in PK-15 cells

•FMDV infection up-regulates miRNA-4331-5p expression.•MiRNA-4331-5p mimics transfection facilitates FMDV replication.•MiRNA-4331-5p inhibitor transfection suppresses FMDV replication.•MiRNA-4331-5p regulates interferon production and antiviral genes expression during FMDV infection. MicroRNAs play vital roles in regulating the battle between pathogens and host cells during viral challenging. MiR-4331 aggravates transmissible gastroenteritis virus (TGEV) -induced mitochondrial damage, also suppresses transcription of TGEV gene 7 via targeting cellular CDCA7. Otherwise, miR-4331-5p affects H1N1/2009 influenza A virus replication by targeting viral HA and NS. However, whether microRNA ssc-miR-4331-5p (miR-4331-5p) regulates foot and mouth virus (FMDV) replication remains unclear. To explore the role of miR-4331-5p in FMDV infection, we detected the expression level of miR-4331-5p in porcine kidney (PK-15) cells. The results showed that FMDV infection directly upregulates miR-4331-5p expression, while transfection of mimics or inhibitor of miR-4331-5p promotes or inhibits FMDV replication. Further investigation clearly showed that miR-4331-5p increases FMDV replication through inhibiting type I interferon pathways. These data demonstrate that miR-4331-5p plays an important role in regulating FMDV replication.