Changes of microRNAs expression profiles from red swamp crayfish (Procambarus clarkia) hemolymph exosomes in response to WSSV infection.

MicroRNAs (miRNAs) as short noncoding RNAs play important regulatory roles in diverse biological processes by degrading the target mRNAs, and could be delivered by exosomes. WSSV is a highly pathogenic and prevalent virus, and has brought high mortality of P. clarkia. Till present, no studies focus on the miRNAs changes in exosomes during WSSV infection. To understand the different virulence of WSSV on miRNAs expression in P. clarkia hemolymph exosome, the deep sequencing was performed to compare the small RNA libraries from the hemolymph exosome of P. clarkia individuals with or without WSSV infections. From the TEM observations, NTA and Western Blot analysis, the extracted exosomes were well identified with classic characteristics. The 209 conserved miRNAs and 250 novel miRNAs were identified from the small RNA libraries. In response to WSSV infection, there were about 98 miRNAs significantly up-regulated and 59 miRNAs significantly down-regulated. The target genes prediction, GO and KEGG enrichment analysis revealed that some target genes of P. clarkia miRNAs were grouped mainly into the categories of biological regulation, immune system process, signal pathway and other more functions. This is the first report of comprehensive identification of P. clarkia hemolymph exosome miRNAs being differentially regulated in response to WSSV infection. These results will help to understand the hemolymph exosome miRNAs response to different virulence WSSV infection.