The serum proteome of Atlantic salmon, Salmo salar, during pancreas disease (PD) following infection with salmonid alphavirus subtype 3 (SAV3).

M Braceland,M F Mcloughlin,W Weir,P D Eckersall,D A Graham,R Bickerdike,J Tinsley,C Wallace,D Cockerill,R J Burchmore

doi:10.1016/j.jprot.2013.10.016

Abstract

Salmonid alphavirus is the aetological agent of pancreas disease (PD) in marine Atlantic salmon, Salmo salar, and rainbow trout, Oncorhynchus mykiss, with most outbreaks in Norway caused by SAV subtype 3 (SAV3). This atypical alphavirus is transmitted horizontally causing a significant economic impact on the aquaculture industry. This histopathological and proteomic study, using an established cohabitational experimental model, investigated the correlation between tissue damage during PD and a number of serum proteins associated with these pathologies in Atlantic salmon. The proteins were identified by two-dimensional electrophoresis, trypsin digest and peptide MS/MS fingerprinting. A number of humoral components of immunity which may act as biomarkers of the disease were also identified. For example, creatine kinase, enolase and malate dehydrogenase serum concentrations were shown to correlate with pathology during PD. In contrast, hemopexin, transferrin, and apolipoprotein, amongst others, altered during later stages of the disease and did not correlate with tissue pathologies. This approach has given new insight into not only PD but also fish disease as a whole, by characterisation of the protein response to infection, through pathological processes to tissue recovery.Biological significanceSalmonid alphavirus causes pancreas disease (PD) in Atlantic salmon, Salmo salar, and has a major economic impact on the aquaculture industry. A proteomic investigation of the change to the serum proteome during PD has been made with an established experimental model of the disease. Serum proteins were identified by two-dimensional electrophoresis, trypsin digest and peptide MS/MS fingerprinting with 72 protein spots being shown to alter significantly over the 12 week period of the infection. The concentrations of certain proteins in serum such as creatine kinase, enolase and malate dehydrogenase were shown to correlate with tissue pathology while other proteins such as hemopexin, transferrin, and apolipoprotein, altered in concentration during later stages of the disease and did not correlate with tissue pathologies. The protein response to infection may be used to monitor disease progression and enhance understanding of the pathology of PD.

Highlights

First described in farmed Atlantic salmon, Salmo salar L., from Scotland, in 1976, pancreas disease (PD) is characterized by lethargy and other behavioural modifications, sequential acute necrosis of the pancreatic acinar cells, cardiomyopathy and skeletal muscle necrosis, fibrosis and degeneration whilst damage to the kidney, liver and brain can be observed in some individuals [1,2,3]
Salmonid alphavirus is the aetological agent of pancreas disease (PD) in marine Atlantic salmon, Salmo salar, and rainbow trout, Oncorhynchus mykiss, with most outbreaks in Norway caused by salmonid alphavirus (SAV) subtype 3 (SAV3)
Prostaglandin-D synthase in serum has not been studied to any extent in fish or other species immunity, inhibition of the protein has been shown to correlate with muscular necrosis [49] which may have significance in PD and other viral diseases that cause necrosis of muscle fibres. This histopathological and proteomic study of PD in Atlantic salmon, Salmo salar, has identified numerous serum proteins which are altered in abundance during the disease

Summary

Introduction

First described in farmed Atlantic salmon, Salmo salar L., from Scotland, in 1976, pancreas disease (PD) is characterized by lethargy and other behavioural modifications, sequential acute necrosis of the pancreatic acinar cells, cardiomyopathy and skeletal muscle necrosis, fibrosis and degeneration whilst damage to the kidney, liver and brain can be observed in some individuals [1,2,3]. Subsequent to the initial histopathological characterization of PD in Scotland the disease was described in other regions including: North America [4], Norway [5], Ireland [6], France and Spain [7] It was not until 1995, that the aetiological agent of the disease was discovered and given the name salmon pancreas disease virus (SPDV) [8]. The aetiological agent of sleeping disease (SD), which shares the same pathogenesis as PD, in freshwater rainbow trout, Oncorhynchus mykiss, was isolated and named sleeping disease virus (SDV) [9]. SDV and SPDV were identified as two related isolates of the same virus and the species name salmonid alphavirus (SAV) proposed

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