title: Comparison of transcriptomic responses to pancreas disease (PD) and heart and skeletal muscle inflammation (HSMI) in heart of Atlantic salmon (Salmo salar L).
abstract: Pancreas disease (PD) and heart and skeletal muscle inflammation (HSMI) are viral diseases associated with SAV (salmonid alphavirus) and PRV (piscine reovirus), which induce systemic infections and pathologies in cardiac and skeletal muscle tissue of farmed Atlantic salmon (Salmo salar L), resulting in severe morbidity and mortality. While general features of the clinical symptoms and pathogenesis of salmonid viral diseases are relatively well studied, much less is known about molecular mechanisms associated with immunity and disease-specific changes. In this study, transcriptomic analyses of heart tissue from PD and HSMI challenged Atlantic salmon were done, focusing on the mature phases of both diseases at respectively 28-35 and 42-77 days post infection. A large number of immune genes was activated in both trials with prevalence of genes associated with early innate antiviral responses, their expression levels being slightly higher in PD challenged fish. Activation of the IFN axis was in parallel with inflammatory changes that involved diverse humoral and cellular factors. Adaptive immune response genes were more pronounced in fish with HSMI, as suggested by increased expression of a large number of genes associated with differentiation and maturation of B lymphocytes and cytotoxic T cells. A similar down-regulation of non-immune genes such as myofiber and mitochondrial proteins between diseases was most likely reflecting myocardial pathology. A suite of genes important for cardiac function including B-type natriuretic peptide and four neuropeptides displayed differential expression between PD and HSMI. Comparison of results revealed common and distinct features and added to the understanding of both diseases at their mature phases with typical clinical pictures. A number of genes that showed disease-specific changes can be of interest for diagnostics.
authors.affiliation: Nofima AS, P.O. Box 6122, N-9291 Tromsø, Norway. Electronic address: lill-heidi.johansen@nofima.no.
authors.forename: Lill-Heidi
authors.initials: LH
authors.lastname: Johansen
authors.affiliation: Norwegian College of Fisheries Science, UiT The Arctic University of Norway, N-9037 Tromsø, Norway.
authors.forename: Hanna L
authors.initials: HL
authors.lastname: Thim
authors.affiliation: Nofima AS, P.O. Box 6122, N-9291 Tromsø, Norway.
authors.forename: Sven Martin
authors.initials: SM
authors.lastname: Jørgensen
authors.affiliation: Nofima AS, P.O. Box 6122, N-9291 Tromsø, Norway; Sechenov Institute of Evolutionary Physiology and Biochemistry, M. Toreza Av. 44, Saint Petersburg 194223, Russia.
authors.forename: Sergey
authors.initials: S
authors.lastname: Afanasyev
authors.affiliation: Norwegian College of Fisheries Science, UiT The Arctic University of Norway, N-9037 Tromsø, Norway.
authors.forename: Guro
authors.initials: G
authors.lastname: Strandskog
authors.affiliation: Norwegian Veterinary Institute, P.O. Box 750, N-0106 Oslo, Norway.
authors.forename: Torunn
authors.initials: T
authors.lastname: Taksdal
authors.affiliation: Norwegian College of Fisheries Science, UiT The Arctic University of Norway, N-9037 Tromsø, Norway.
authors.forename: Kjersti
authors.initials: K
authors.lastname: Fremmerlid
authors.affiliation: Fish Vet Group, 22 Carsegate Road, Inverness IV3 8EX, UK.
authors.forename: Marion
authors.initials: M
authors.lastname: McLoughlin
authors.affiliation: Norwegian College of Fisheries Science, UiT The Arctic University of Norway, N-9037 Tromsø, Norway.
authors.forename: Jorunn B
authors.initials: JB
authors.lastname: Jørgensen
authors.affiliation: Nofima AS, P.O. Box 6122, N-9291 Tromsø, Norway.
authors.forename: Aleksei
authors.initials: A
authors.lastname: Krasnov
mesh_terms: D000524:Alphavirus / Q000502:physiology*; D018354:Alphavirus Infections / Q000276:immunology / Q000662:veterinary / Q000821:virology; D000818:Animals; D015536:Down-Regulation; D005393:Fish Diseases / Q000276:immunology* / Q000821:virology; D006331:Heart Diseases / Q000276:immunology / Q000662:veterinary* / Q000821:virology; D007249:Inflammation / Q000276:immunology / Q000662:veterinary / Q000821:virology; D009206:Myocardium / Q000276:immunology / Q000378:metabolism; D010182:Pancreatic Diseases / Q000276:immunology / Q000662:veterinary* / Q000821:virology; D012087:Reoviridae / Q000502:physiology*; D012088:Reoviridae Infections / Q000276:immunology / Q000662:veterinary / Q000821:virology; D020317:Salmo salar
keywords: Atlantic salmon; Heart; Heart and skeletal muscle inflammation; Immune genes; Pancreas disease; Transcriptomic responses