Profiling the transcriptome response of Atlantic salmon head kidney to formalin-killed Renibacterium salmoninarum

2020 ◽  
Vol 98 ◽  
pp. 937-949 ◽  
Author(s):  
Khalil Eslamloo ◽  
Surendra Kumar ◽  
Albert Caballero-Solares ◽  
Hajarooba Gnanagobal ◽  
Javier Santander ◽  
...  
Keyword(s):  
Atlantic Salmon ◽  
Head Kidney ◽  
Renibacterium Salmoninarum ◽  
Transcriptome Response

scholarly journals Lumpfish (Cyclopterus lumpus) Is Susceptible to Renibacterium salmoninarum Infection and Induces Cell-Mediated Immunity in the Chronic Stage

2021 ◽  
Vol 12 ◽  
Author(s):  
Hajarooba Gnanagobal ◽  
Trung Cao ◽  
Ahmed Hossain ◽  
My Dang ◽  
Jennifer R. Hall ◽  
...  
Keyword(s):  
Immune Response ◽  
Atlantic Salmon ◽  
Fish Species ◽  
Clinical Signs ◽  
Head Kidney ◽  
Acute Phase Reactant ◽  
High Dose ◽  
Cell Mediated Immunity ◽  
Renibacterium Salmoninarum ◽  
Cyclopterus Lumpus

Renibacterium salmoninarum is a Gram-positive, intracellular pathogen that causes Bacterial Kidney Disease (BKD) in several fish species in freshwater and seawater. Lumpfish (Cyclopterus lumpus) is utilized as a cleaner fish to biocontrol sea lice infestation in Atlantic salmon (Salmo salar) farms. Atlantic salmon is susceptible to R. salmoninarum, and it can transfer the infection to other fish species. Although BKD outbreaks have not been reported in lumpfish, its susceptibility and immune response to R. salmoninarum is unknown. In this study, we evaluated the susceptibility and immune response of lumpfish to R. salmoninarum infection. Groups of lumpfish were intraperitoneally (i.p.) injected with either R. salmoninarum (1×107, 1×108, or 1×109 cells dose-1) or PBS (control). R. salmoninarum infection kinetics and mortality were followed for 98 days post-infection (dpi). Transcript expression levels of 33 immune-relevant genes were measured in head kidney (n = 6) of fish infected with 1×109 cells/dose and compared to the control at 28 and 98 dpi. Infected lumpfish displayed characteristic clinical signs of BKD. Lumpfish infected with high, medium, and low doses had a survival rate of 65%, 93%, and 95%, respectively. Mortality in the high-dose infected group stabilized after 50 dpi, but R. salmoninarum persisted in the fish tissues until 98 dpi. Cytokines (il1β, il8a, il8b), pattern recognition receptors (tlr5a), interferon-induced effectors (rsad2, mxa, mxb, mxc), and iron regulation (hamp) and acute phase reactant (saa5) related genes were up-regulated at 28 dpi. In contrast, cell-mediated adaptive immunity-related genes (cd4a, cd4b, ly6g6f, cd8a, cd74) were down-regulated at 28 dpi, revealing the immune suppressive nature of R. salmoninarum. However, significant upregulation of cd74 at 98 dpi suggests induction of cell-mediated immune response. This study showed that R. salmoninarum infected lumpfish in a similar fashion to salmonid fish species and caused a chronic infection, enhancing cell-mediated adaptive immune response.

scholarly journals Investigating mechanisms underlying genetic resistance to Salmon Rickettsial Syndrome in Atlantic salmon using RNA sequencing

BMC Genomics ◽  
2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Carolina P. Moraleda ◽  
Diego Robledo ◽  
Alejandro P. Gutiérrez ◽  
Jorge del-Pozo ◽  
José M. Yáñez ◽  
...  
Keyword(s):  
Atlantic Salmon ◽  
Rna Sequencing ◽  
Host Resistance ◽  
Large Population ◽  
Genetic Resistance ◽  
Head Kidney ◽  
Breeding Values ◽  
Association Analyses ◽  
Polygenic Trait ◽  
Salmon Rickettsial Syndrome

Abstract Background Salmon Rickettsial Syndrome (SRS), caused by Piscirickettsia salmonis, is one of the primary causes of morbidity and mortality in Atlantic salmon aquaculture, particularly in Chile. Host resistance is a heritable trait, and functional genomic studies have highlighted genes and pathways important in the response of salmon to the bacteria. However, the functional mechanisms underpinning genetic resistance are not yet well understood. In the current study, a large population of salmon pre-smolts were challenged with P. salmonis, with mortality levels recorded and samples taken for genotyping. In parallel, head kidney and liver samples were taken from animals of the same population with high and low genomic breeding values for resistance, and used for RNA-Sequencing to compare their transcriptome profile both pre and post infection. Results A significant and moderate heritability (h2 = 0.43) was shown for the trait of binary survival. Genome-wide association analyses using 38 K imputed SNP genotypes across 2265 animals highlighted that resistance is a polygenic trait. Several thousand genes were identified as differentially expressed between controls and infected samples, and enriched pathways related to the host immune response were highlighted. In addition, several networks with significant correlation with SRS resistance breeding values were identified, suggesting their involvement in mediating genetic resistance. These included apoptosis, cytoskeletal organisation, and the inflammasome. Conclusions While resistance to SRS is a polygenic trait, this study has highlighted several relevant networks and genes that are likely to play a role in mediating genetic resistance. These genes may be future targets for functional studies, including genome editing, to further elucidate their role underpinning genetic variation in host resistance.

scholarly journals Secretome Profiling of Atlantic Salmon Head Kidney Leukocytes Highlights the Role of Phagocytes in the Immune Response to Soluble β-Glucan

2021 ◽  
Vol 12 ◽  
Author(s):  
Dimitar B. Iliev ◽  
Guro Strandskog ◽  
Mehrdad Sobhkhez ◽  
Jack A. Bruun ◽  
Jorunn B. Jørgensen
Keyword(s):  
Immune System ◽  
Atlantic Salmon ◽  
Primary Cultures ◽  
Head Kidney ◽  
Cell Types ◽  
Mononuclear Phagocytes ◽  
Immunostimulatory Activity ◽  
Complement Receptor 3 ◽  
Bacteria And Fungi

β‐Glucans (BG) are glucose polymers which are produced in bacteria and fungi but not in vertebrate organisms. Being recognized by phagocytic leukocytes including macrophages and neutrophils through receptors such as dectin-1 and Complement receptor 3 (CR3), the BG are perceived by the innate immune system of vertebrates as foreign substances known as Pathogen Associated Molecular Patterns (PAMPs). The yeast-derived BG has been recognized for its potent biological activity and it is used as an immunomodulator in human and veterinary medicine. The goal of the current study was to characterize the immunostimulatory activity of soluble yeast BG in primary cultures of Atlantic salmon (Salmo salar) head kidney leukocytes (HKLs) in which phagocytic cell types including neutrophils and mononuclear phagocytes predominate. The effect of BG on the secretome of HKL cultures, including secretion of extracellular vesicles (EVs) and soluble protein55s was characterized through western blotting and mass spectrometry. The results demonstrate that, along with upregulation of proinflammatory genes, BG induces secretion of ubiquitinated proteins (UbP), MHCII-containing EVs from professional antigen presenting cells as well as proteins derived from granules of polymorphonuclear granulocytes (PMN). Among the most abundant proteins identified in BG-induced EVs were beta-2 integrin subunits, including CD18 and CD11 homologs, which highlights the role of salmon granulocytes and mononuclear phagocytes in the response to soluble BG. Overall, the current work advances the knowledge about the immunostimulatory activity of yeast BG on the salmon immune system by shedding light on the effect of this PAMP on the secretome of salmon leukocytes.

scholarly journals Identification of a New Infectious Pancreatic Necrosis Virus (IPNV) Variant in Atlantic Salmon (Salmo salar L.) that can Cause High Mortality Even in Genetically Resistant Fish

2021 ◽  
Vol 12 ◽  
Author(s):  
Borghild Hillestad ◽  
Stein Johannessen ◽  
Geir Olav Melingen ◽  
Hooman K. Moghadam
Keyword(s):  
Amino Acid ◽  
Atlantic Salmon ◽  
Pancreatic Necrosis ◽  
Single Gene ◽  
Head Kidney ◽  
Comparative Sequence Analysis ◽  
Infectious Pancreatic Necrosis Virus ◽  
Life Cycles ◽  
New Variant ◽  
Infectious Pancreatic Necrosis

Infectious pancreatic necrosis (IPN) is an important viral disease of salmonids that can affect fish during various life cycles. In Atlantic salmon, selecting for genetically resistant fish against IPN has been one of the most highly praised success stories in the history of fish breeding. During the late 2000s, the findings that resistance against this disease has a significant genetic component, which is mainly controlled by variations in a single gene, have helped to reduce the IPN outbreaks to a great extent. In this paper, we present the identification of a new variant of the IPN virus from a field outbreak in Western Norway that had caused mortality, even in genetically resistant salmon. We recovered and assembled the full-length genome of this virus, following the deep-sequencing of the head-kidney transcriptome. The comparative sequence analysis revealed that for the critical amino acid motifs, previously found to be associated with the degree of virulence, the newly identified variant is similar to the virus’s avirulent form. However, we detected a set of deduced amino acid residues, particularly in the hypervariable domain of the VP2, that collectively are unique to this variant compared to all other reference sequences assessed in this study. We suggest that these mutations have likely equipped the virus with the capacity to escape the host defence mechanism more efficiently, even in the genetically deemed IPN resistant fish.

Sign in / Sign up

Export Citation Format

Share Document