MicroRNA transcriptome analysis of sea perch brain cells after infection with RGNNV

MicroRNA (miRNA) plays important roles in regulating immune system against viral infection. Nervous necrosis virus (NNV) is one of the most destructive fish viruses and affected more than 120 marine and freshwater teleost species including sea perch (Lateolabrax japonicus). To understand the regulating pattern of miRNAs to the immune system against NNV infection, the study carries out high-throughput sequencing of Lateolabrax japonicus brain cells without or with RGNNV infection at 12 and 24h. Consequently, 59 known differentially expressed (DE) miRNAs and 61 novel DE miRNAs were identified. Transcript levels of four DE miRNAs were validated by qRT-PCR, and the result was consistent with sequencing data. Furthermore, the effect of miRNAs on RGNNV infection was investigated. The result showed that lja-miR-135 and lja-miR-145 promoted RGNNV proliferation, while lja-miR-183 suppressed the infection of the virus, indicating that they might be potential targets for development of anti-viral drugs. Meanwhile, targets of DE miRNAs were predicted and the KEGG analysis of DE miRNA targets showed that the significantly enriched pathway were autophagy related signaling pathway. Expression pattern of four genes involving autophagy pathway and their corelate miRNAs confirmed the negative regulation of miRNAs to target genes. This study is of great value to understand the roles of fish miRNA in host immune response to virus.