Transcriptomic Identification and Functional Assessment of Candidate Host Factors Affecting Akabane Virus Replication

Akabane virus (AKAV) causes abortion, stillbirth, and congenital malformations in ruminants, yet the transcriptional response of Madin-Darby bovine kidney (MDBK) cells and the roles of infection-responsive host genes in AKAV replication remain incompletely characterized. We profiled AKAV-infected and time-matched mock-infected MDBK cells by RNA sequencing at 12 and 24 h post-infection (hpi). Differentially expressed genes (DEGs) were examined using Gene Ontology functional classification and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis, six DEGs were evaluated by RT-qPCR, and OAS2 and ZBP1 were assessed by overexpression in BHK-21 cells. We identified 119 DEGs at 12 hpi (82 upregulated and 37 downregulated) and 149 at 24 hpi (85 upregulated and 64 downregulated). The DEG sets were associated with antiviral defense, interferon responses, pattern recognition receptor signaling, DNA replication, cell cycle regulation, chromosome organization, and metabolism. RT-qPCR measurements were consistent with the RNA-seq trends. OAS2 and ZBP1 transcripts were significantly upregulated at 12 hpi, while ZBP1 transcript levels remained significantly elevated at 24 hpi. Overexpression of either gene was associated with reductions in AKAV Gc protein abundance, viral RNA levels, and infectious titers. These results define transcriptional changes in AKAV-infected MDBK cells and nominate OAS2 and ZBP1 as candidate host factors for further investigation, while their endogenous roles in bovine cells remain to be established.