Identification of differentially expressed Atlantic salmon miRNAs responding to salmonid alphavirus (SAV) infection

BMC Genomics

Research Article

Oleg Agafonov¹  Bjørn Høyheim²  Nardos Tesfaye Woldemariam³  Rune Andreassen³  Ine Østråt Egeland³  Hilde Sindre⁴ 

[1] Bioinformatics Core Facility, Department of Core Facilities, Institute of Cancer Research, Radium hospital, part of Oslo University Hospital, Oslo, Norway;Department of Basic Sciences and Aquatic Medicine, School of Veterinary Medicine, Norwegian University of Life Sciences, Ullevålsveien 72, 0454, Oslo, Norway;Department of Pharmacy and Biomedical and Laboratory Sciences, Faculty of Health Sciences, Oslo and Akershus University College of Applied Sciences, Pilestredet 50, N-0130, Oslo, Norway;Norwegian Veterinary Institute, PB 750 Sentrum, N-106, Oslo, Norway;

关键词: miRNA;    Virus;    Atlantic salmon;    Innate immune response;   

DOI  :  10.1186/s12864-017-3741-3

 received in 2016-10-29, accepted in 2017-04-27,  发布年份 2017

来源: Springer

【 摘 要 】

BackgroundMicroRNAs (miRNAs) control multiple biological processes including the innate immune responses by negative post-transcriptional regulation of gene expression. As there were no studies on the role(s) of miRNAs in viral diseases in Atlantic salmon, we aimed to identify miRNAs responding to salmonid alphavirus (SAV) infection. Their expression were studied at different time points post infection with SAV isolates associated with different mortalities. Furthermore, the genome sequences of the identified miRNAs were analysed to reveal putative cis-regulatory elements, and, finally, their putative target genes were predicted.ResultsTwenty differentially expressed miRNAs (DE miRNAs) were identified. The expression of the majority of these increased post infection with maximum levels reached after the viral load were stabilized or decreasing. On the other hand, some miRNAs (e.g. the miRNA-21 family) showed decreased expression at the early time points post infection. There were significant differences in the temporal expression of individual miRNA associated with different SAV isolates. Target gene prediction in SAV responsive immune network genes showed that seventeen of the DE miRNAs could target 24 genes (e.g. IRF3, IRF7). Applying the Atlantic salmon transcriptome as input 28 more immune network genes were revealed as putative targets (e.g. IRF5, IRF4). The majority of the predicted target genes promote inflammatory response. The upstream sequences of the miRNA genes revealed a high density of cis-regulatory sequences known as binding sites for immune network transcription factors (TFs). A high expression in the late phase could therefore be due to increased transcription promoted by immune response activated TFs. Based on the in silico target predictions, we discuss their putative roles as early promotors or late inhibitors of inflammation. We propose that the differences in expressions associated with different SAV isolates could contribute to their differences in mortality rates.ConclusionsThis study represents the first steps in exploring miRNAs important in viral-host interaction in Atlantic salmon. We identified several miRNAs responding to SAV infection. Some likely to prohibit harmful inflammation while other may promote an early immune response. Their predicted functions need to be validated and further studied in functional assays to fully understand their roles in immune homeostasis.

【 授权许可】

CC BY   
© The Author(s). 2017