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Midtbø HMD, Eichner C, Hamre LA, Dondrup M, Flesland L, Tysseland KH, Kongshaug H, Borchel A, Skoge RH, Nilsen F, Øvergård AC. Salmon louse labial gland enzymes: implications for host settlement and immune modulation. Front Genet 2024; 14:1303898. [PMID: 38299097 PMCID: PMC10828956 DOI: 10.3389/fgene.2023.1303898] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2023] [Accepted: 12/18/2023] [Indexed: 02/02/2024] Open
Abstract
Salmon louse (Lepeophtheirus salmonis) is a skin- and blood-feeding ectoparasite, infesting salmonids. While feeding, labial gland proteins from the salmon louse may be deposited on the Atlantic salmon (Salmo salar) skin. Previously characterized labial gland proteins are involved in anti-coagulation and may contribute to inhibiting Atlantic salmon from mounting a sufficient immune response against the ectoparasite. As labial gland proteins seem to be important in the host-parasite interaction, we have, therefore, identified and characterized ten enzymes localized to the labial gland. They are a large group of astacins named L. salmonis labial gland astacin 1-8 (LsLGA 1-8), one serine protease named L. salmonis labial gland serine protease 1 (LsLGSP1), and one apyrase named L. salmonis labial gland apyrase 1 (LsLGAp1). Protein domain predictions showed that LsLGA proteins all have N-terminal ShK domains, which may bind to potassium channels targeting the astacins to its substrate. LsLGA1 and -4 are, in addition, expressed in another gland type, whose secrete also meets the host-parasite interface. This suggests that LsLGA proteins may have an anti-microbial function and may prevent secondary infections in the wounds. LsLGAp1 is predicted to hydrolyze ATP or AMP and is, thereby, suggested to have an immune dampening function. In a knockdown study targeting LsLGSP1, a significant increase in IL-8 and MMP13 at the skin infestation site was seen under LsLGSP1 knockdown salmon louse compared to the control, suggesting that LsLGSP1 may have an anti-inflammatory effect. Moreover, most of the identified labial gland proteins are expressed in mature copepodids prior to host settlement, are not regulated by starvation, and are expressed at similar or higher levels in lice infesting the salmon louse-resistant pink salmon (Oncorhynchus gorbuscha). This study, thereby, emphasizes the importance of labial gland proteins for host settlement and their immune dampening function. This work can further contribute to anti-salmon louse treatment such as vaccine development, functional feed, or gene-edited salmon louse-resistant Atlantic salmon.
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Affiliation(s)
| | - Christiane Eichner
- Sea Lice Research Centre, Department of Biological Sciences, University of Bergen, Bergen, Norway
| | - Lars Are Hamre
- Sea Lice Research Centre, Department of Biological Sciences, University of Bergen, Bergen, Norway
| | - Michael Dondrup
- Sea Lice Research Centre, Department of Informatics, University of Bergen, Bergen, Norway
| | - Linn Flesland
- Sea Lice Research Centre, Department of Biological Sciences, University of Bergen, Bergen, Norway
| | | | - Heidi Kongshaug
- Sea Lice Research Centre, Department of Biological Sciences, University of Bergen, Bergen, Norway
| | - Andreas Borchel
- Sea Lice Research Centre, Department of Biological Sciences, University of Bergen, Bergen, Norway
| | - Renate Hvidsten Skoge
- Sea Lice Research Centre, Department of Biological Sciences, University of Bergen, Bergen, Norway
| | - Frank Nilsen
- Sea Lice Research Centre, Department of Biological Sciences, University of Bergen, Bergen, Norway
| | - Aina-Cathrine Øvergård
- Sea Lice Research Centre, Department of Biological Sciences, University of Bergen, Bergen, Norway
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Stølen Ugelvik M, Mennerat A, Mæhle S, Dalvin S. Repeated exposure affects susceptibility and responses of Atlantic salmon ( Salmo salar) towards the ectoparasitic salmon lice ( Lepeophtheirus salmonis). Parasitology 2023; 150:990-1005. [PMID: 37705306 PMCID: PMC10941223 DOI: 10.1017/s0031182023000847] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2023] [Revised: 09/05/2023] [Accepted: 09/05/2023] [Indexed: 09/15/2023]
Abstract
Atlantic salmon (Salmo salar) is repeatedly exposed to and infected with ectoparasitic salmon lice (Lepeophtheirus salmonis) both in farms and in nature. However, this is not reflected in laboratory experiments where fish typically are infected only once. To investigate if a previous lice infection affects host response to subsequent infections, fish received 4 different experimental treatments; including 2 groups of fish that had previously been infected either with adult or infective salmon lice larvae (copepodids). Thereafter, fish in all treatment groups were infected with either a double or a single dose of copepodids originating from the same cohort. Fish were sampled when lice had developed into the chalimus, the pre-adult and the adult stage, respectively. Both the specific growth rate and cortisol levels (i.e. a proxy for stress) of the fish differed between treatments. Lice success (i.e. ability to infect and survive on the host) was higher in naïve than in previously infected fish (pre-adult stage). The expression of immune and wound healing transcripts in the skin also differed between treatments, and most noticeable was a higher upregulation early in the infection in the group previously infected with copepodids. However, later in the infection, the least upregulation was observed in this group, suggesting that previous exposure to salmon lice affects the response of Atlantic salmon towards subsequent lice infections.
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Affiliation(s)
- Mathias Stølen Ugelvik
- Institute of Marine Research, Bergen, Norway
- Department of Biological Sciences, University of Bergen, Bergen, Norway
| | - Adele Mennerat
- Department of Biological Sciences, University of Bergen, Bergen, Norway
| | - Stig Mæhle
- Institute of Marine Research, Bergen, Norway
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Gou M, Duan X, Li J, Wang Y, Li Q, Pang Y, Dong Y. Spatial Metabolomics Reveals the Multifaceted Nature of Lamprey Buccal Gland and Its Diverse Mechanisms for Blood-Feeding. Commun Biol 2023; 6:881. [PMID: 37640823 PMCID: PMC10462737 DOI: 10.1038/s42003-023-05250-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2022] [Accepted: 08/16/2023] [Indexed: 08/31/2023] Open
Abstract
Lampreys are blood-sucking vampires in marine environments. From a survival perspective, it is expected that the lamprey buccal gland exhibits a repository of pharmacologically active components to modulate the host's homeostasis, inflammatory and immune responses. By analyzing the metabolic profiles of 14 different lamprey tissues, we show that two groups of metabolites in the buccal gland of lampreys, prostaglandins and the kynurenine pathway metabolites, can be injected into the host fish to assist lamprey blood feeding. Prostaglandins are well-known blood-sucking-associated metabolites that act as vasodilators and anticoagulants to maintain vascular homeostasis and are involved in inflammatory responses. The vasomotor reactivity test on catfish aortic ring showed that kynurenine can also relax the blood vessels of the host fish, thus improving the blood flow of the host fish at the bite site. Finally, a lamprey spatial metabolomics database ( https://www.lampreydb.com ) was constructed to assist studies using lampreys as animal model.
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Affiliation(s)
- Meng Gou
- College of Life Science, Liaoning Normal University, Dalian, 116081, China
- Lamprey Research Center, Liaoning Normal University, Dalian, 116081, China
| | - Xuyuan Duan
- College of Life Science, Liaoning Normal University, Dalian, 116081, China
- Lamprey Research Center, Liaoning Normal University, Dalian, 116081, China
| | - Jun Li
- College of Life Science, Liaoning Normal University, Dalian, 116081, China
- Lamprey Research Center, Liaoning Normal University, Dalian, 116081, China
| | - Yaocen Wang
- College of Life Science, Liaoning Normal University, Dalian, 116081, China
- Lamprey Research Center, Liaoning Normal University, Dalian, 116081, China
| | - Qingwei Li
- College of Life Science, Liaoning Normal University, Dalian, 116081, China
- Lamprey Research Center, Liaoning Normal University, Dalian, 116081, China
| | - Yue Pang
- College of Life Science, Liaoning Normal University, Dalian, 116081, China.
- Lamprey Research Center, Liaoning Normal University, Dalian, 116081, China.
| | - Yonghui Dong
- Life Sciences Core Facilities, Weizmann Institute of Science, Rehovot, 7610001, Israel.
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Øvergård AC, Eichner C, Nuñez-Ortiz N, Kongshaug H, Borchel A, Dalvin S. Transcriptomic and targeted immune transcript analyses confirm localized skin immune responses in Atlantic salmon towards the salmon louse. FISH & SHELLFISH IMMUNOLOGY 2023:108835. [PMID: 37236552 DOI: 10.1016/j.fsi.2023.108835] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Revised: 05/12/2023] [Accepted: 05/16/2023] [Indexed: 05/28/2023]
Abstract
Atlantic salmon (Salmo salar) are highly susceptible to infestations with the ectoparasite Lepeophtheirus salmonis, the salmon louse. Infestations elicit an immune response in the fish, but the response does not lead to parasite clearance, nor does it protect against subsequent infestations. It is, however, not known why the immune response is not adequate, possibly because the local response directly underneath the louse has been poorly evaluated. The present study describes the transcriptomic response by RNA sequencing of skin at the site of copepodid attachment. Analysing differentially expressed genes, 2864 were higher and 1357 were lower expressed at the louse attachment site compared to uninfested sites in the louse infested fish, while gene expression at uninfested sites were similar to uninfested control fish. The transcriptional patterns of selected immune genes were further detailed in three skin compartments/types: Whole skin, scales only and fin tissue. The elevation of pro-inflammatory cytokines and immune cell marker transcripts observed in whole skin and scale samples were not induced in fin, and a higher cytokine transcript level in scale samples suggest it can be used as a nonlethal sampling method to enhance selective breeding trials. Furthermore, the immune response was followed in both skin and anterior kidney as the infestation developed. Here, newly moulted preadult 1 stage lice induced a higher immune response than chalimi and adult lice. Overall, infestation with salmon louse induce a modest but early immune response with an elevation of mainly innate immune transcripts, with the response primarily localized to the site of attachment.
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Affiliation(s)
- Aina-Cathrine Øvergård
- SLCR-Sea Lice Research Centre, Department of Biological Sciences, University of Bergen, Pb. 7803, Bergen, NO-5020, Norway.
| | - Christiane Eichner
- SLCR-Sea Lice Research Centre, Department of Biological Sciences, University of Bergen, Pb. 7803, Bergen, NO-5020, Norway
| | - Noelia Nuñez-Ortiz
- SLCR-Sea Lice Research Centre, Disease and Pathogen Transmission, Institute of Marine Research, Pb. 1870 Nordnes, Bergen, NO-5817, Norway
| | - Heidi Kongshaug
- SLCR-Sea Lice Research Centre, Department of Biological Sciences, University of Bergen, Pb. 7803, Bergen, NO-5020, Norway
| | - Andreas Borchel
- SLCR-Sea Lice Research Centre, Department of Biological Sciences, University of Bergen, Pb. 7803, Bergen, NO-5020, Norway
| | - Sussie Dalvin
- SLCR-Sea Lice Research Centre, Disease and Pathogen Transmission, Institute of Marine Research, Pb. 1870 Nordnes, Bergen, NO-5817, Norway
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Ugelvik MS, Dalvin S. The effect of different intensities of the ectoparasitic salmon lice (Lepeophtheirus salmonis) on Atlantic salmon (Salmo salar). JOURNAL OF FISH DISEASES 2022; 45:1133-1147. [PMID: 35612902 PMCID: PMC9544591 DOI: 10.1111/jfd.13649] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Revised: 04/29/2022] [Accepted: 05/02/2022] [Indexed: 06/01/2023]
Abstract
The effect of different intensities of the ectoparasitic salmon lice (Lepeophtheirus salmonis) on stress, growth and the expression of immune and wound healing transcripts in the skin of Atlantic salmon (Salmo salar) was investigated. Lice infection success and survival were similar at the chalimus and preadult stage in the low and high dose group, but infection success and survival were significantly lower in the high than in the low dose group at the adult stage. The expression of investigated transcripts was not correlated to lice intensities, but several of them were significantly differently expressed locally in the skin at the site of lice attachment in infected fish compared to controls. This included an up-regulation of pro-inflammatory markers at the site of lice attachment (e.g., interleukin 1-beta, interleukin 8 and the acute phase protein serum amyloid A), a reduction of markers of adaptive immunity (cluster of differentiation 8-alpha and immunoglobulin M) and decreased expression of the anti-inflammatory cytokine interleukin 10.
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Ugelvik MS, Mæhle S, Dalvin S. Temperature affects settlement success of ectoparasitic salmon lice (Lepeophtheirus salmonis) and impacts the immune and stress response of Atlantic salmon (Salmo salar). JOURNAL OF FISH DISEASES 2022; 45:975-990. [PMID: 35397139 PMCID: PMC9320951 DOI: 10.1111/jfd.13619] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Revised: 03/09/2022] [Accepted: 03/11/2022] [Indexed: 06/01/2023]
Abstract
In this study, the effect of temperature on Atlantic salmon (Salmo salar) stress and immune response to the ectoparasitic salmon lice (Lepeophtheirus salmonis) was investigated. We found that infestation affected the expression of several immune and wound healing transcripts in the skin especially at the site of lice attachment compared to un-infested control fish. Moreover, expression patterns in the skin of infested fish suggest that host immune responses towards salmon lice are impaired at low temperatures. However, reduced lice infestation success and survival at the lowest investigated temperatures suggest that cold water temperatures are more detrimental to the lice than their fish hosts. Finally, temperature affected the stress response of the fish and infected fish had a higher increase in cortisol levels in response to handling (a stressor) than un-infested controls.
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Affiliation(s)
| | - Stig Mæhle
- Institute of Marine ResearchBergenNorway
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Small, charged proteins in salmon louse (Lepeophtheirus salmonis) secretions modulate Atlantic salmon (Salmo salar) immune responses and coagulation. Sci Rep 2022; 12:7995. [PMID: 35568726 PMCID: PMC9107468 DOI: 10.1038/s41598-022-11773-w] [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: 12/18/2021] [Accepted: 04/28/2022] [Indexed: 11/08/2022] Open
Abstract
Little is known about glandular proteins secreted from the skin- and blood-feeding ectoparasite salmon louse (Lepeophtheirus salmonis). The labial gland has ducts extending into the oral cavity of the lice, and the present study aimed to identify novel genes expressed by this gland type and to investigate their role in modulation of host parameters at the lice feeding site. Five genes associated with labial gland function were identified and named Lepeophteirus salmonis labial gland protein (LsLGP) 1-4 and 1 like (LsLGP1L). All LsLGPs were predicted to be small charged secreted proteins not encoding any known protein domains. Functional studies revealed that LsLGP1 and/or LsLGP1L regulated the expression of other labial gland genes. Immune dampening functions were indicated for LsLGP2 and 3. Whereas LsLGP2 was expressed throughout the parasitic life cycle and found to dampen inflammatory cytokines, LsLGP3 displayed an increased expression in mobile stages and appeared to dampen adaptive immune responses. Expression of LsLGP4 coincided with moulting to the mobile pre-adult I stage where hematophagous feeding is initiated, and synthetic LsLGP4 decreased the clotting time of Atlantic salmon plasma. Results from the present study confirm that the salmon louse secretes immune modulating and anti-coagulative proteins with a potential application in new immune based anti-salmon louse treatments.
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Glutathione S-Transferases in Marine Copepods. JOURNAL OF MARINE SCIENCE AND ENGINEERING 2021. [DOI: 10.3390/jmse9091025] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
The glutathione S-transferase (GST) is a complex family of phase II detoxification enzymes, known for their ability to catalyze the conjugation of the reduced form of glutathione (GSH) to a wide variety of endogenous and exogenous electrophilic compounds for detoxification purposes. In marine environments, copepods are constantly exposed to multiple exogenous stressors, thus their capability of detoxification is key for survival. Full identification of the GST family in copepods has been limited only to few species. As for insects, the GST family includes a wide range of genes that, based on their cellular localization, can be divided in three classes: cytosolic, microsomal, and mitochondrial. The role of GSTs might have class-specific features, thus understanding the nature of the GST family has become crucial. This paper covers information of the GST activity in marine copepods based on studies investigating gene expression, protein content, and enzymatic activity. Using published literature and mining new publicly available transcriptomes, we characterized the multiplicity of the GST family in copepods from different orders and families, highlighting the possible role of these genes as biomarker for ocean health status monitoring.
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