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Widdicombe M, Coff L, Nowak BF, Ramsland PA, Bott NJ. Understanding the host response of farmed fish to blood flukes (Trematoda: Aporocotylidae) for developing new treatment strategies. FISH & SHELLFISH IMMUNOLOGY 2024; 149:109613. [PMID: 38710341 DOI: 10.1016/j.fsi.2024.109613] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2024] [Revised: 04/29/2024] [Accepted: 05/03/2024] [Indexed: 05/08/2024]
Abstract
Aporocotylids (Trematoda: Digenea), also known as fish blood flukes infect the circulatory system of fish leading to serious health problems and mortality. Aporocotylids are a particular concern for farmed fish as infection intensity can increase within the farming environment and lead to mortalities. In the context of managing these infections, one of the most crucial aspects to consider is the host response of the infected fish against these blood flukes. Understanding the response is essential to improving current treatment strategies that are largely based on the use of anthelmintic praziquantel to manage infections in aquaculture. This review focuses on the current knowledge of farmed fish host responses against the different life stages of aporocotylids. New treatment strategies that are able to provide protection against reinfections should be a long-term goal and is not possible without understanding the fish response to infection and the interactions between host and parasite.
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Affiliation(s)
- Maree Widdicombe
- School of Science, STEM College, RMIT University, Bundoora, Victoria, 3083, Australia
| | - Lachlan Coff
- School of Science, STEM College, RMIT University, Bundoora, Victoria, 3083, Australia; Australian Centre for Disease Preparedness, CSIRO, East Geelong, Victoria, 3219, Australia
| | - Barbara F Nowak
- School of Science, STEM College, RMIT University, Bundoora, Victoria, 3083, Australia; Institute for Marine and Antarctic Studies, University of Tasmania, Locked Bag 1370, Launceston, Tasmania, 7250, Australia
| | - Paul A Ramsland
- School of Science, STEM College, RMIT University, Bundoora, Victoria, 3083, Australia; Department of Immunology, Monash University, Melbourne, Victoria, 3004. Australia; Department of Surgery, Austin Health, University of Melbourne, Heidelberg, Victoria, 3084, Australia
| | - Nathan J Bott
- School of Science, STEM College, RMIT University, Bundoora, Victoria, 3083, Australia.
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Leal Y, Valenzuela-Muñoz V, Casuso A, Benavente BP, Gallardo-Escárate C. Comparative Transcriptomics in Atlantic Salmon Head Kidney and SHK-1 Cell Line Exposed to the Sea Louse Cr-Cathepsin. Genes (Basel) 2023; 14:genes14040905. [PMID: 37107663 PMCID: PMC10138087 DOI: 10.3390/genes14040905] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 04/03/2023] [Accepted: 04/07/2023] [Indexed: 04/29/2023] Open
Abstract
The development of vaccines against sea lice in salmon farming is complex, expensive, and takes several years for commercial availability. Recently, transcriptome studies in sea louse have provided valuable information for identifying relevant molecules with potential use for fish vaccines. However, the bottleneck is the in vivo testing of recombinant protein candidates, the dosage, and the polyvalent formulation strategies. This study explored a cell-based approach to prospect antigens as candidate vaccines against sea lice by comparison with immunized fish. Herein, SHK-1 cells and Atlantic salmon head kidney tissue were exposed to the antigen cathepsin identified from the sea louse Caligus rogercresseyi. The cathepsin protein was cloned and recombinantly expressed in Escherichia coli, and then SHK-1 cell lines were stimulated with 100 ng/mL cathepsin recombinant for 24 h. In addition, Atlantic salmons were vaccinated with 30 ug/mL recombinant protein, and head kidney samples were then collected 30 days post-immunization. SHK-1 cells and salmon head kidney exposed to cathepsin were analyzed by Illumina RNA sequencing. The statistical comparisons showed differences in the transcriptomic profiles between SHK-1 cells and the salmon head kidney. However, 24.15% of the differentially expressed genes were shared. Moreover, putative gene regulation through lncRNAs revealed tissue-specific transcription patterns. The top 50 up and downregulated lncRNAs were highly correlated with genes involved in immune response, iron homeostasis, pro-inflammatory cytokines, and apoptosis. Also, highly enriched pathways related to the immune system and signal transduction were shared between both tissues. These findings highlight a novel approach to evaluating candidate antigens for sea lice vaccine development, improving the antigens screening in the SHK-1 cell line model.
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Affiliation(s)
- Yeny Leal
- Interdisciplinary Center for Aquaculture Research (INCAR), Universidad de Concepción, P.O. Box 160-C, Concepción 4030000, Chile
- Laboratory of Biotechnology and Aquatic Genomics, Department of Oceanography, Universidad de Concepción, Concepción 4030000, Chile
| | - Valentina Valenzuela-Muñoz
- Interdisciplinary Center for Aquaculture Research (INCAR), Universidad de Concepción, P.O. Box 160-C, Concepción 4030000, Chile
- Laboratory of Biotechnology and Aquatic Genomics, Department of Oceanography, Universidad de Concepción, Concepción 4030000, Chile
| | - Antonio Casuso
- Interdisciplinary Center for Aquaculture Research (INCAR), Universidad de Concepción, P.O. Box 160-C, Concepción 4030000, Chile
- Laboratory of Biotechnology and Aquatic Genomics, Department of Oceanography, Universidad de Concepción, Concepción 4030000, Chile
| | - Bárbara P Benavente
- Interdisciplinary Center for Aquaculture Research (INCAR), Universidad de Concepción, P.O. Box 160-C, Concepción 4030000, Chile
- Laboratory of Biotechnology and Aquatic Genomics, Department of Oceanography, Universidad de Concepción, Concepción 4030000, Chile
| | - Cristian Gallardo-Escárate
- Interdisciplinary Center for Aquaculture Research (INCAR), Universidad de Concepción, P.O. Box 160-C, Concepción 4030000, Chile
- Laboratory of Biotechnology and Aquatic Genomics, Department of Oceanography, Universidad de Concepción, Concepción 4030000, Chile
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Valenzuela-Aviles P, Torrealba D, Figueroa C, Mercado L, Dixon B, Conejeros P, Gallardo-Matus J. Why vaccines fail against Piscirickettsiosis in farmed salmon and trout and how to avoid it: A review. Front Immunol 2022; 13:1019404. [PMID: 36466828 PMCID: PMC9714679 DOI: 10.3389/fimmu.2022.1019404] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Accepted: 10/24/2022] [Indexed: 09/28/2023] Open
Abstract
Piscirickettsiosis is the most severe, persistent, and damaging disease that has affected the Chilean salmon industry since its origins in the 1980s. As a preventive strategy for this disease, different vaccines have been developed and used over the last 30 years. However, vaccinated salmon and trout frequently die in the sea cages and the use of antibiotics is still high demonstrating the low efficiency of the available vaccines. The reasons why the vaccines fail so often are still debated, but it could involve different extrinsic and intrinsic factors. Among the extrinsic factors, mainly associated with chronic stress, we can distinguish: 1) biotic including coinfection with sea lice, sealions attacks or harmful algal blooms; 2) abiotic including low oxygen or high temperature; and 3) farm-management factors including overcrowding or chemical delousing treatments. Among the intrinsic factors, we can distinguish: 1) fish-related factors including host's genetic variability (species, population and individual), sex or age; 2) pathogen-related factors including their variability and ability to evade host immune responses; and 3) vaccine-related factors including low immunogenicity and poor matches with the circulating pathogen strain. Based on the available evidence, in order to improve the development and the efficacy of vaccines against P. salmonis we recommend: a) Do not perform efficacy evaluations by intraperitoneal injection of pathogens because they generate an artificial protective immune response, instead cohabitation or immersion challenges must be used; b) Evaluate the diversity of pathogen strains in the field and ensure a good antigenic match with the vaccines; c) Investigate whether host genetic diversity could be improved, e.g. through selection, in favor of better and longer responses to vaccination; d) To reduce the stressful effects at the cage level, controlling the co-infection of pathogens and avoiding fish overcrowding. To date, we do not know the immunological mechanisms by which the vaccines against P. salmonis may or may not generate protection. More studies are required to identify what type of response, cellular or molecular, is required to develop effective vaccines.
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Affiliation(s)
- Paula Valenzuela-Aviles
- Laboratorio de Genética y Genómica Aplicada, Escuela de Ciencias del Mar, Pontificia Universidad Católica de Valparaíso, Valparaíso, Chile
| | - Débora Torrealba
- Laboratorio de Genética y Genómica Aplicada, Escuela de Ciencias del Mar, Pontificia Universidad Católica de Valparaíso, Valparaíso, Chile
| | - Carolina Figueroa
- Laboratorio de Genética y Genómica Aplicada, Escuela de Ciencias del Mar, Pontificia Universidad Católica de Valparaíso, Valparaíso, Chile
| | - Luis Mercado
- Grupo de Marcadores Inmunológicos en Organismos Acuáticos, Pontificia Universidad Católica de Valparaíso, Instituto de Biología, Valparaíso, Chile
| | - Brian Dixon
- Department of Biology, Faculty of Science, University of Waterloo, Waterloo, Canada
| | - Pablo Conejeros
- Centro de Investigación y Gestión de Recursos Naturales (CIGREN), Facultad de Ciencias, Instituto de Biología, Universidad de Valparaíso, Valparaíso, Chile
| | - José Gallardo-Matus
- Laboratorio de Genética y Genómica Aplicada, Escuela de Ciencias del Mar, Pontificia Universidad Católica de Valparaíso, Valparaíso, Chile
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Dual RNA-Seq Analysis Reveals Transcriptome Effects during the Salmon–Louse Interaction in Fish Immunized with Three Lice Vaccines. Vaccines (Basel) 2022; 10:vaccines10111875. [PMID: 36366383 PMCID: PMC9692469 DOI: 10.3390/vaccines10111875] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2022] [Revised: 10/27/2022] [Accepted: 10/27/2022] [Indexed: 11/11/2022] Open
Abstract
Due to the reduced efficacy of delousing drugs used for sea lice control in salmon aquaculture, fish vaccines have emerged as one of the most sustainable strategies in animal health. Herein, the availability of C. rogercresseyi and Salmo salar genomes increases the capability of identifying new candidate antigens for lice vaccines using RNA sequencing and computational tools. This study aimed to evaluate the effects of two recombinant antigens characterized as peritrophin and cathepsin proteins on the transcriptome profiling of Atlantic salmon during a sea lice infestation. Four experimental groups were used: Peritrophin, cathepsin, and peritrophin/cathepsin (P/C), and PBS as the control. C. rogercresseyi female, S. salar head kidney, and skin tissue samples were sampled at 25 days post-infestation (dpi) for Illumina sequencing and RNA-seq analysis. Differential gene expression, gene ontology, and chromosomal expression analyses were performed. Furthermore, the dual RNA-seq analysis approach was performed to simultaneously explore host and pathogen transcriptomes, identifying functional associations for vaccine design. The morphometry of female sea lice exposed to immunized fish was also evaluated. The RNA-Seq analysis exhibited prototype-dependent transcriptome modulation, showing a conspicuous competition for metal ions during the infestation. Moreover, Dual RNA-seq analysis revealed vaccine-dependent gene patterns in both the host and the pathogen. Notably, significant morphometric differences between lice collected from immunized and control fish were observed, where cathepsin and P/C showed 57% efficacy. This study showed the potential of two proteins as lice vaccines for the salmon industry, suggesting novel molecular mechanisms between host–parasite interactions.
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Exploring Sea Lice Vaccines against Early Stages of Infestation in Atlantic Salmon (Salmo salar). Vaccines (Basel) 2022; 10:vaccines10071063. [PMID: 35891227 PMCID: PMC9324576 DOI: 10.3390/vaccines10071063] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Revised: 05/31/2022] [Accepted: 06/01/2022] [Indexed: 11/17/2022] Open
Abstract
The sea louse Caligus rogercresseyi genome has opened the opportunity to apply the reverse vaccinology strategy for identifying antigens with potential effects on lice development and its application in sea lice control. This study aimed to explore the efficacy of three sea lice vaccines against the early stage of infestation, assessing the transcriptome modulation of immunized Atlantic salmon. Therein, three experimental groups of Salmo salar (Atlantic salmon) were vaccinated with the recombinant proteins: Peritrophin (prototype A), Cathepsin (prototype B), and the mix of them (prototype C), respectively. Sea lice infestation was evaluated during chalimus I-II, the early-infective stages attached at 7-days post infestation. In parallel, head kidney and skin tissue samples were taken for mRNA Illumina sequencing. Relative expression analyses of genes were conducted to identify immune responses, iron transport, and stress responses associated with the tested vaccines during the early stages of sea lice infection. The vaccine prototypes A, B, and C reduced the parasite burden by 24, 44, and 52% compared with the control group. In addition, the RNA-Seq analysis exhibited a prototype-dependent transcriptome modulation. The high expression differences were observed in genes associated with metal ion binding, molecular processes, and energy production. The findings suggest a balance between the host’s inflammatory response and metabolic process in vaccinated fish, increasing their transcriptional activity, which can alter the early host–parasite interactions. This study uncovers molecular responses produced by three vaccine prototypes at the early stages of infestation, providing new knowledge for sea lice control in the salmon aquaculture.
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Valenzuela-Muñoz V, Benavente BP, Casuso A, Leal Y, Valenzuela-Miranda D, Núñez-Acuña G, Sáez-Vera C, Gallardo-Escárate C. Transcriptome and morphological analysis in Caligus rogercresseyi uncover the effects of Atlantic salmon vaccination with IPath®. FISH & SHELLFISH IMMUNOLOGY 2021; 117:169-178. [PMID: 34389379 DOI: 10.1016/j.fsi.2021.08.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/01/2021] [Revised: 08/04/2021] [Accepted: 08/06/2021] [Indexed: 06/13/2023]
Abstract
It is known that iron transporter proteins and their regulation can modulate the fish's immune system, suggesting these proteins as a potential candidate for fish vaccines. Previous studies have evidenced the effects of Atlantic salmon immunized with the chimeric iron-related protein named IPath® against bacterial and ectoparasitic infections. The present study aimed to explore the transcriptome modulation and the morphology of the sea louse Caligus rogercresseyi in response to Atlantic salmon injected with IPath®. Herein, Atlantic salmon were injected with IPath® and challenged to sea lice in controlled laboratory conditions. Then, female adults were collected after 25 days post-infection for molecular and morphological evaluation. Transcriptome analysis conducted in lice collected from immunized fish revealed high modulation of transcripts compared with the control groups. Notably, the low number of up/downregulated transcripts was mainly found in lice exposed to the IPath® fish group. Among the top-25 differentially expressed genes, Vitellogenin, Cytochrome oxidases, and proteases genes were strongly downregulated, suggesting that IPath® can alter lipid transport, hydrogen ion transmembrane transport, and proteolysis. The morphological analysis in lice collected from IPath® fish revealed abnormal embryogenesis and inflammatory processes of the genital segment. Furthermore, head kidney, spleen, and skin were also analyzed in immunized fish to evaluate the transcription expression of immune and iron homeostasis-related genes. The results showed downregulation of TLR22, MCHII, IL-1β, ALAs, HO, BLVr, GSHPx, and Ferritin genes in head kidney and skin tissues; meanwhile, those genes did not show significant differences in spleen tissue. Overall, our findings suggest that IPath® can be used to enhance the fish immune response, showing a promissory commercial application against lice infections.
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Affiliation(s)
- Valentina Valenzuela-Muñoz
- Interdisciplinary Center for Aquaculture Research (INCAR), University of Concepción, Concepción, Chile; Laboratory of Biotechnology and Aquatic Genomics, Department of Oceanography, University of Concepción, Concepción, Chile
| | - Bárbara P Benavente
- Interdisciplinary Center for Aquaculture Research (INCAR), University of Concepción, Concepción, Chile; Laboratory of Biotechnology and Aquatic Genomics, Department of Oceanography, University of Concepción, Concepción, Chile
| | - Antonio Casuso
- Interdisciplinary Center for Aquaculture Research (INCAR), University of Concepción, Concepción, Chile; Laboratory of Biotechnology and Aquatic Genomics, Department of Oceanography, University of Concepción, Concepción, Chile
| | - Yeny Leal
- Interdisciplinary Center for Aquaculture Research (INCAR), University of Concepción, Concepción, Chile; Laboratory of Biotechnology and Aquatic Genomics, Department of Oceanography, University of Concepción, Concepción, Chile
| | - Diego Valenzuela-Miranda
- Interdisciplinary Center for Aquaculture Research (INCAR), University of Concepción, Concepción, Chile; Laboratory of Biotechnology and Aquatic Genomics, Department of Oceanography, University of Concepción, Concepción, Chile
| | - Gustavo Núñez-Acuña
- Interdisciplinary Center for Aquaculture Research (INCAR), University of Concepción, Concepción, Chile; Laboratory of Biotechnology and Aquatic Genomics, Department of Oceanography, University of Concepción, Concepción, Chile
| | - Constanza Sáez-Vera
- Interdisciplinary Center for Aquaculture Research (INCAR), University of Concepción, Concepción, Chile; Laboratory of Biotechnology and Aquatic Genomics, Department of Oceanography, University of Concepción, Concepción, Chile
| | - Cristian Gallardo-Escárate
- Interdisciplinary Center for Aquaculture Research (INCAR), University of Concepción, Concepción, Chile; Laboratory of Biotechnology and Aquatic Genomics, Department of Oceanography, University of Concepción, Concepción, Chile.
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