Zebrafish fin immune responses during high mortality infections with viral haemorrhagic septicemia rhabdovirus. A proteomic and transcriptomic approach

Abstract

BackgroundDespite rhabdoviral infections being one of the best known fish diseases, the gene expression changes induced at the surface tissues after the natural route of infection (infection-by-immersion) have not been described yet. This work describes the differential infected versus non-infected expression of proteins and immune-related transcripts in fins and organs of zebrafish Danio rerio shortly after infection-by-immersion with viral haemorrhagic septicemia virus (VHSV).ResultsTwo-dimensional differential gel electrophoresis detected variations on the protein levels of the enzymes of the glycolytic pathway and cytoskeleton components but it detected very few immune-related proteins. Differential expression of immune-related gene transcripts estimated by quantitative polymerase chain reaction arrays and hybridization to oligo microarrays showed that while more transcripts increased in fins than in organs (spleen, head kidney and liver), more transcripts decreased in organs than in fins. Increased differential transcript levels in fins detected by both arrays corresponded to previously described infection-related genes such as complement components (c3b, c8 and c9) or class I histocompatibility antigens (mhc1) and to newly described genes such as secreted immunoglobulin domain (sid4), macrophage stimulating factor (mst1) and a cluster differentiation antigen (cd36).ConclusionsThe genes described would contribute to the knowledge of the earliest molecular events occurring in the fish surfaces at the beginning of natural rhabdoviral infections and/or might be new candidates to be tested as adjuvants for fish vaccines.

Use of Microarray Technology to Improve DNA Vaccines in Fish Aquaculture - The Rhabdoviral Model

“…A number of IFN-related genes (including the unknown LB3 (8)) and mx increased 7 days after injection, thereby confirming the observations made in previous studies using reverse transcriptase-quantitative polymerase chain reaction (RT-qPCR) (Acosta et al, 2005;Robertsen, 2008). Further studies included differential gene expression in kidneys from Japanese flounder injected with the HRV G gene (protective) in comparison with the N gene •, Infection-by-immersion of zebrafish with VHSV and expression on fins (Encinas et al, 2010). ■, VHSV infection-byimmersion of zebrafish and expression in internal organs (head kidney, liver and spleeen) (Encinas et al, 2010).…”

“…Therefore, an upregulated response of immune-related genes was greatest in fin tissues, while a downregulated response was most detected in the internal organ responses. The latter might be targets of viral inhibitory signals early after infection (Encinas et al, 2010). These results showed that 2 days after infection-by-immersion, VHSV had not yet caused an strong response from zebrafish internal organs, which contrasts with reports in other fish at later times after infection-by-injection (such as ifn1, mx, il1b, tnfa, etc) (Acosta et al, 2006;Samuel, 2001;Tafalla et al, 2007;Tafalla et al, 2005) or infection-by-immersion (Jorgensen et al, 2011;Zhang et al, 2009).…”

“…In addition, large-scale experimentation with zebrafish is easier than with other fish models and zebrafish are susceptible to several viruses, most of these belonging to the fish rhabdoviral family (Sullivan & Kim, 2008). Of these, VHSV (Novoa et al, 2006) was chosen in a recent study using microarrays (Encinas et al, 2010) over IHNV , snake-head rhabdovirus (SHRV) (Phelan et al, 2005) and spring viremia of carp (SVC) (Sanders et al, 2003), because only in the VHSV/zebrafish model have infection-by-immersion (the natural route of infection) and successful vaccination been described (Novoa et al, 2006).…”

“…Further studies included differential gene expression in kidneys from Japanese flounder injected with the HRV G gene (protective) in comparison with the N gene •, Infection-by-immersion of zebrafish with VHSV and expression on fins (Encinas et al, 2010). ■, VHSV infection-byimmersion of zebrafish and expression in internal organs (head kidney, liver and spleeen) (Encinas et al, 2010). □, Injection of trout with the IHNV G gene and expression in muscle tissue with p>0.01 (Purcell et al, 2006b).…”

Recommendations for Health Monitoring and Reporting for Zebrafish Research Facilities

“…62 Many aquatic viruses are not host specific, which increases the risk that naive laboratory zebrafish may be susceptible to viral diseases transmitted from other fish species housed in the same facility or from zebrafish acquired from aquaculture facilities or pet stores. 58 Zebrafish have been shown to be experimentally susceptible to a number of fish viruses, [63][64][65][66] including infectious spleen and kidney necrosis virus, [67][68][69][70] a Megalocytivirus, which infects a very broad range of fish hosts 71,72 and is prevalent in the tropical ornamental fish trade. 73,74 Zebrafish have also been shown to be experimentally susceptible to a commercially important Rhabdovirus, spring viremia of carp virus (SVCV), 75,76 which has restricted importation of laboratory zebrafish into Canada and other nations.…”