Transcriptome analysis of rainbow trout in response to non-virion (NV) protein of viral haemorrhagic septicaemia virus (VHSV)

Abstract

The non-virion (NV) protein of viral haemorrhagic septicaemia virus (VHSV), an economically important fish novirhabdovirus, has been implicated in the interference of some host innate mechanisms (i.e. apoptosis) in vitro. This work aimed to characterise the immune-related transcriptome changes in rainbow trout induced by NV protein that have not yet been established in vivo. For that purpose, immune-targeted microarrays were used to analyse the transcriptomes from head kidney and spleen of rainbow trout (Oncorhynchus mykiss) after injection of recombinant NV (rNV). Results showed the extensive downregulation (and in some cases upregulation) of many innate and adaptive immune response genes not related previously to VHSV infection. The newly identified genes belonged to VHSV-induced genes (vigs), tumour necrosis factors, Toll-like receptors, antigen processing and presentation, immune co-stimulatory molecules, interleukins, macrophage chemotaxis, transcription factors, etc. Classification of differentially downregulated genes into rainbow trout immune pathways identified stat1 and jun/atf1 transcription factor genes as the most representative of the multipath gene targets of rNV. Altogether, these results contribute to define the role and effects of NV in trout by orchestrating an immunosuppression of the innate immune responses for favouring viral replication upon VHSV infection. Finally, these transcriptome results open up the possibility to find out new strategies against VHSV and better understand the interrelationships between some immune pathways in trout.

Innate Multigene Family Memories Are Implicated in the Viral-Survivor Zebrafish Phenotype

“…Early immunosuppression could be induced by rhabdoviruses to favor their initial replication, a phenomena that has been described for other viruses [ 42 – 48 ]. In this respect, the non-virion NV protein of VHSV was recently identified as an extensive immunosuppressor viral protein in trout [ 49 ] and similar preliminary results were confirmed in zebrafish (unpublished). Alternatively, cell migration (as suggested by il1b/rac1 upregulation) to the entry sites of VHSV (fins, skin, blood, etc), may cause a cell depletion in lymphoid organs, thus explaining the transcript downregulation in lymphoid tissues.…”

Transcriptomic and proteomic analyses of splenic immune mechanisms of rainbow trout (Oncorhynchus mykiss) infected by Aeromonas salmonicida subsp. salmonicida

“…The transcriptome profiling of the gills in two rainbow trout strains provided insights into their distinct immune responses to A. salmonicida [11]. Multiple transcriptome analysis has been performed in rainbow trout in response to other pathogens or pathogenesis-related proteins, such as infectious hematopoietic necrosis virus (IHNV) [12], Tetracapsuloides bryosalmonae (Myxozoa) [13] and non-virion (NV) protein of viral hemorrhagic septicemia virus (VHSV) [14]. Although, transcriptome analysis has provided a new gateway for identifying levels of gene expression and new transcripts and has thus become a powerful tool for species that lack reference genome information, a comparison of mRNA expression levels, protein amounts, and enzymatic activities has revealed low correlations between metabolome and transcriptome, indicating that transcriptome analysis is insufficient to understand protein dynamics or biochemical regulation [15,16].…”

Untitled

“…Zebrafish is an appropriate model organism for studying developmental immunology. Its significant characteristics for various studies also for modeling many infections which is affecting fish (Chinchilla, Encinas, Estepa, Coll, & Gomez-Casado, 2015;López-Muñoz, Roca, Sepulcre, Meseguer, & Mulero, 2010;Rowe, Withey, & Neely, 2014) and humans (Acik, Yuksel, Ulucan & Cetinkaya, 2016;Goody, Sullivan, & Kim, 2014).…”