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Chuphal B, Sathoria P, Rai U, Roy B. Sexual dimorphism in NLR transcripts and its downstream signaling protein IL-1ꞵ in teleost Channa punctata (Bloch, 1793). Sci Rep 2024; 14:1923. [PMID: 38253695 PMCID: PMC10803744 DOI: 10.1038/s41598-024-51702-7] [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: 07/29/2023] [Accepted: 01/08/2024] [Indexed: 01/24/2024] Open
Abstract
Nucleotide-binding oligomerization domain-like receptors (NOD-like receptors or NLRs) are a family of intracellular pattern recognition receptors (PRRs) that initiates as well as regulate inflammatory responses. NLRs are characterized by a centrally located nucleotide binding domain and a leucine rich repeat domain at the C-terminal responsible for the recognition of intracellular microbe-associated molecular patterns (MAMPs) and danger-associated molecular patterns (DAMPs). In the present study in adult spotted snakehead we have investigated the sex-dependent tissue distribution of NLRs known to be associated with inflammation in teleost namely NOD1, NOD2, NLRC3, NLRC5, and NLRX1. Further, the sexual dimorphism in the expression of NLR transcript as well as the pro-inflammatory protein IL-1β was explored in fish under normal conditions, and in fish exposed to bacterial lipopolysaccharide (LPS). The NLRs show ubiquitous and constitutive expression in all the tissues. Moreover, a prominent disparity between males and females was observed in the basal expression of these genes in various tissues. The sexual dimorphism in NLR expression was also prominent when fish were exposed to LPS. Similarly, IL-1β exhibited sexual dimorphism in both normal as well as LPS-exposed fish.
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Affiliation(s)
- Bhawna Chuphal
- Department of Zoology, Miranda House, University of Delhi, Delhi, 110007, India
| | - Priyanka Sathoria
- Department of Zoology, Maitreyi College, University of Delhi, Chanakyapuri, Delhi, 110021, India
| | - Umesh Rai
- University of Jammu, Jammu and Kashmir, Jammu, 180006, India.
| | - Brototi Roy
- Department of Zoology, Maitreyi College, University of Delhi, Chanakyapuri, Delhi, 110021, India.
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2
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Campbell JH, Dang X, Rodríguez-Ramos T, Carpio Y, Estrada MP, Dixon B. The effect of PACAP administration on LPS-induced cytokine expression in the Atlantic salmon SHK-1 cell line. FISH AND SHELLFISH IMMUNOLOGY REPORTS 2023; 5:100116. [PMID: 37753327 PMCID: PMC10518582 DOI: 10.1016/j.fsirep.2023.100116] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2023] [Revised: 09/13/2023] [Accepted: 09/16/2023] [Indexed: 09/28/2023] Open
Abstract
Recent work has identified pituitary adenylate cyclase activating polypeptide (PACAP) as a potential antimicrobial and immune stimulating agent which may be suitable for use in aquaculture. However, its effects on teleost immunity are not well studied and may be significantly different than what has been observed in mammals. In this study we examined the effects of PACAP on the Atlantic salmon macrophage cell line SHK-1. PACAP was able to increase the expression of LPS-induced il-1β in at concentrations of 1 uM when administered 24h prior to LPS stimulation. Furthermore, concentrations as low as 40nM had an effect when administered both 24h prior and in tandem with LPS. PACAP was also capable of increasing the expression of il-1β and tnf-α in SHK-1 cells challenged with a low dose of heat-killed Flavobacterium columnare. We attempted to get a better understanding of the mechanism underlying this enhancement of il-1β expression by manipulating downstream signaling of PACAP with inhibitors of phosphodiesterase and phospholipase C activity. We found that inducing cAMP accumulation with phosphodiesterase inhibitors failed to recapitulate the effect of PACAP administration on LPS-mediated il-1β expression by PACAP, while use of a phospholipase C inhibitor caused a PACAP-like enhancement in LPS-mediated il-1β expression. Interestingly, the VPAC1 receptor inhibitor PG97-269, but not the PAC1 inhibitor max.d.4, also was capable of causing a PACAP-like enhancement in LPS-mediated il-1β expression. This suggests that fish do not utilize the PACAP receptors in the same manner as mammals, but that it still exerts an immunostimulatory effect that make it a good immunostimulant for use in aquaculture.
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Affiliation(s)
- James Hugh Campbell
- Department of Biology, University of Waterloo, 200 University Ave W, Waterloo, ON N2L 3G1
| | - Xiaoqing Dang
- Department of Biology, University of Waterloo, 200 University Ave W, Waterloo, ON N2L 3G1
| | - Tania Rodríguez-Ramos
- Department of Biology, University of Waterloo, 200 University Ave W, Waterloo, ON N2L 3G1
| | - Yamila Carpio
- Center for Genetic Engineering and Biotechnology, Avenida 31 No. 15802, Havana, Cuba
| | - Mario P. Estrada
- Center for Genetic Engineering and Biotechnology, Avenida 31 No. 15802, Havana, Cuba
| | - Brian Dixon
- Department of Biology, University of Waterloo, 200 University Ave W, Waterloo, ON N2L 3G1
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3
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Frenette AP, Rodríguez-Ramos T, Zanuzzo F, Ramsay D, Semple SL, Soullière C, Rodríguez-Cornejo T, Heath G, McKenzie E, Iwanczyk J, Bruder M, Aucoin MG, Gamperl AK, Dixon B. Expression of Interleukin-1β protein in vitro,exvivo and in vivo salmonid models. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2023; 147:104767. [PMID: 37406840 DOI: 10.1016/j.dci.2023.104767] [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: 05/07/2023] [Revised: 06/30/2023] [Accepted: 07/01/2023] [Indexed: 07/07/2023]
Abstract
Interleukin-1β (IL-1β) is one of the first cytokines expressed during immune responses, and its levels are affected by many factors, including stress. To date, it has only been possible to measure IL-1β transcript (mRNA) expression quantitatively in fish using qPCR. This is because previous studies that measured IL-1β protein concentrations in these taxa used western blotting, which only provides qualitative data. To advance our knowledge of fish IL-1β biology, and because post-translational processing plays a critical role in the activation of this molecule, we developed a quantitative enzyme-linked immunosorbent assay (ELISA) to accurately measure the concentration of IL-1β protein in several cell cultures and in vivo in salmonids. We compared changes in IL-1β protein levels to the expression of its mRNA. The developed ELISA was quite sensitive and has a detection limit of 12.5 pg/mL. The tools developed, and information generated through this research, will allow for a more accurate and complete understanding of IL-1β's role in the immune response of salmonids.The assay described here has the potential to significantly advance our ability to assess fish health and immune status.
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Affiliation(s)
- Aaron P Frenette
- Department of Biology, University of Waterloo, Waterloo, ON, Canada
| | | | - Fabio Zanuzzo
- Department of Ocean Sciences, Memorial University of Newfoundland and Labrador, St. John's, NL, Canada; Universidade Estadual Paulista - UNESP, Centro de Aquicultura da UNESP, Faculdade de Ciências Agrárias e Veterinárias, Via de Acesso Prof. Paulo Donato Castellane, Jaboticabal, CEP, 14884-900, SP, Brazil
| | - Devyn Ramsay
- Department of Ocean Sciences, Memorial University of Newfoundland and Labrador, St. John's, NL, Canada
| | - Shawna L Semple
- Department of Biology, University of Waterloo, Waterloo, ON, Canada
| | - Cheryl Soullière
- Department of Biology, University of Waterloo, Waterloo, ON, Canada
| | | | - George Heath
- Department of Biology, University of Waterloo, Waterloo, ON, Canada
| | - Emily McKenzie
- Department of Biology, University of Waterloo, Waterloo, ON, Canada
| | | | - Mark Bruder
- Department of Chemical Engineering, University of Waterloo, Waterloo, ON, Canada
| | - Marc G Aucoin
- Department of Chemical Engineering, University of Waterloo, Waterloo, ON, Canada
| | - A Kurt Gamperl
- Department of Ocean Sciences, Memorial University of Newfoundland and Labrador, St. John's, NL, Canada
| | - Brian Dixon
- Department of Biology, University of Waterloo, Waterloo, ON, Canada.
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4
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Heath G, Semple SL, Rodríguez-Ramos T, Hardy S, Harrison P, Mulder IM, Power M, Dixon B. Surface material of acoustic transmitters influences the inflammatory response of rainbow trout (Oncorhynchus mykiss) during long-term implantation. Vet Immunol Immunopathol 2023; 264:110660. [PMID: 37820428 DOI: 10.1016/j.vetimm.2023.110660] [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: 11/18/2022] [Accepted: 10/04/2023] [Indexed: 10/13/2023]
Abstract
Telemetry tags are a widely used technology for tracking animals that are difficult to observe in their natural environment. This technology has been increasingly used to monitor and study populations of high value salmonid species in Canadian waters. This study expands on a previous study of the impacts of tag implantation on the immune system of Rainbow Trout (Oncorhynchus mykiss). Pro-inflammatory cytokines and protein level markers were examined in fish that underwent peritoneal implantation of three tag types and compared to a sham surgery control group. The different materials on the surface of the tags showed differential immune induction extending over a two-month period. This included peritoneal total protein, IL-1β protein, the immunoglobulins IgT and IgM, as well as pro-inflammatory transcripts in the spleen. These results are suggestive of a prolonged, costly foreign body response which may be differentially induced by the different types of tag coating, with ceramic tags being least immunogenic. Examining tag impacts at the level of the immune system will facilitate the development of more biocompatible tags which will improve data fidelity. This will support more effective strategies for the management of fisheries resources.
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Affiliation(s)
- George Heath
- University of Waterloo, Department of Biology, Waterloo, Canada
| | - Shawna L Semple
- University of Waterloo, Department of Biology, Waterloo, Canada
| | | | - Sarah Hardy
- University of Waterloo, Department of Biology, Waterloo, Canada
| | - Philip Harrison
- Canadian Rivers Institute Faculty of Forestry and Environmental Management, University of New Brunswick, Fredericton, NB, Canada
| | | | - Michael Power
- University of Waterloo, Department of Biology, Waterloo, Canada
| | - Brian Dixon
- University of Waterloo, Department of Biology, Waterloo, Canada.
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5
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Guo H, Whitehouse L, Danzmann R, Dixon B. Effects of juvenile thermal preconditioning on the heat-shock, immune, and stress responses of rainbow trout upon a secondary thermal challenge. Comp Biochem Physiol A Mol Integr Physiol 2023; 280:111413. [PMID: 36893937 DOI: 10.1016/j.cbpa.2023.111413] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Revised: 03/03/2023] [Accepted: 03/03/2023] [Indexed: 03/09/2023]
Abstract
Higher water temperatures and pathogens are both significant factors that negatively affect the welfare of teleost fish. In aquaculture, compared to natural populations, these problems are especially exacerbated, as the animals have relatively limited mobility, and the higher density promotes faster spread of infectious diseases. Because of the potential harm these stressors can inflict, methods that can limit the damage of these stressors are particularly valuable. As a method of interest, early-life thermal preconditioning of animals demonstrated some potential for effective improvements in thermotolerance. However, the potential effects of the method on the immune system via the heat-stress model have not been explored. In this experiment, juvenile-stage thermal preconditioned rainbow trout (Oncorhynchus mykiss) were subjected to a secondary thermal challenge, animals were collected and sampled at the time of lost equilibrium. The effects of preconditioning on the general stress response was assessed by measuring the plasma cortisol levels. In addition, we also examined hsp70 and hsc70 mRNA levels in the spleen and gill tissues, as well as IL-1β, IL-6, TNF-α, IFN-1, β2m, and MH class I transcripts via qRT-PCR. No changes in CTmax were observed between the preconditioned and control cohorts upon the second challenge. IL-1β and IL-6 transcripts were generally upregulated with increased temperature of the secondary thermal challenge, whereas IFN-1 transcripts were upregulated in the spleen, but downregulated in the gills, along with MH class I. The juvenile thermal preconditioning produced a series of changes in transcript levels for IL-1β, TNF-α, IFN-1, and hsp70 but the dynamics of these differences were inconsistent. Finally, analysis of plasma cortisol levels presented significantly lower cortisol levels in the pre-conditioned animals compared to the non-pre-conditioned control cohort.
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Affiliation(s)
- Huming Guo
- University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - Lindy Whitehouse
- University of Waterloo, Waterloo, Ontario N2L 3G1, Canada. https://twitter.com/LindyWhitehouse
| | - Roy Danzmann
- University of Guelph, Guelph, Ontario N1G 2W1, Canada
| | - Brian Dixon
- University of Waterloo, Waterloo, Ontario N2L 3G1, Canada.
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6
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Varga JFA, Brunner SR, Cheng G, Min D, Aucoin MG, Doxey AC, Dixon B. Identification and characterization of a novel peptide from rainbow trout (Oncorhynchus mykiss) with antimicrobial activity against Streptococcus iniae. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2022; 137:104518. [PMID: 36044968 DOI: 10.1016/j.dci.2022.104518] [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: 07/21/2022] [Revised: 08/11/2022] [Accepted: 08/23/2022] [Indexed: 06/15/2023]
Abstract
The overuse and misuse of antibiotics has led to the emergence of antibiotic-resistant bacterial species which remain a challenge to treat therapeutically. Novel and efficacious drugs are desperately needed to combat pathogens. One method to facilitate these discoveries is the use of in silico methods. Computational biology has the power to scan large data sets and screen for potential molecules with antibacterial function. In the current study, an in silico approach was used to identify an antimicrobial peptide (AMP) derived from rainbow trout von Willebrand Factor. The AMP was tested against a panel of aquatic bacterial pathogens and was found to possess antibacterial activity against Streptococcus iniae (S. iniae). Since S. iniae is a zoonotic pathogen, this may be useful in other species as well. The peptide was non-hemolytic and non-cytotoxic at the concentrations tested in rainbow trout cells. Pre-treatment of rainbow trout cells with the peptide did not result in an upregulation of immune genes but stimulating the rainbow trout macrophage/monocyte-like cell line, RTS11, with heat-killed S. iniae, did result in a significant upregulation of the tumor necrosis factor alpha (tnfa) gene. In this study, a new AMP has been identified but its expression, synthesis and role in vivo remains unknown. Nevertheless, the findings presented improve our understanding of fish gill and macrophage responses towards this important zoonotic pathogen.
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Affiliation(s)
- Joseph F A Varga
- Department of Biology, University of Waterloo, Waterloo, N2L 3G1, Canada
| | - Sascha R Brunner
- Groningen Institute for Evolutionary Life Sciences, University of Groningen, 9747 AG Groningen, the Netherlands
| | - Grant Cheng
- Department of Biology, University of Waterloo, Waterloo, N2L 3G1, Canada
| | - Daniel Min
- Department of Biology, University of Waterloo, Waterloo, N2L 3G1, Canada; Department of Chemical Engineering, University of Waterloo, Waterloo, N2L 3G1, Canada
| | - Marc G Aucoin
- Department of Chemical Engineering, University of Waterloo, Waterloo, N2L 3G1, Canada
| | - Andrew C Doxey
- Department of Biology, University of Waterloo, Waterloo, N2L 3G1, Canada
| | - Brian Dixon
- Department of Biology, University of Waterloo, Waterloo, N2L 3G1, Canada.
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7
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Campbell JH, Dixon B, Whitehouse LM. The intersection of stress, sex and immunity in fishes. Immunogenetics 2021; 73:111-129. [PMID: 33426582 DOI: 10.1007/s00251-020-01194-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Accepted: 11/18/2020] [Indexed: 11/27/2022]
Abstract
While sexual dimorphism in immune responses has been documented in other vertebrates, evidence for a similar phenomenon in fish is lacking. Here, we review the relationship between immunity, stress, spawning, and sex hormones in fish to gain a better understanding of sex-based differences in fish immune responses and its consequences for aquaculture. It is well known that there is a strong link between the stress response and immune function in fish. In addition, research to date has demonstrated that sexual dimorphism in the stress response exists in many species; yet, the relationship between the sexual dimorphic stress responses and immune function has rarely been explored together. Aside from stress, spawning is also known to trigger changes in fish immune responses. Estrogens and androgens have been shown to modulate the immune system which could account for differences between the two sexes of fish when spawning; however, evidence regarding the sexual dimorphism of these changes varies between fishes and is likely related to the spawning strategy employed by a given species. Sex hormones are also used in aquaculture practices to produce monosex populations, and exposure to these hormones early in development has been shown to impact the development of immune organs in several fishes. While female fish are generally thought to be more robust than males, aquaculture practices should also consider the role that maternal stress has on the immune function of the offspring and what role this plays in compromising the immune response of farmed fish.
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Affiliation(s)
- James H Campbell
- Department of Biology, University of Waterloo, 200 University Ave W, Waterloo, ON, N2L 3G1, USA
| | - Brian Dixon
- Department of Biology, University of Waterloo, 200 University Ave W, Waterloo, ON, N2L 3G1, USA.
| | - Lindy M Whitehouse
- Department of Biology, University of Waterloo, 200 University Ave W, Waterloo, ON, N2L 3G1, USA
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8
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Song L, Dixon B. Fish and shellfish immunology reports: A new open access journal. FISH AND SHELLFISH IMMUNOLOGY REPORTS 2020; 1:100001. [DOI: 10.1016/j.fsirep.2020.100001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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9
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Hjelmstedt P, Sundh H, Brijs J, Ekström A, Sundell KS, Berg C, Sandblom E, Bowman J, Morgenroth D, Gräns A. Effects of prophylactic antibiotic-treatment on post-surgical recovery following intraperitoneal bio-logger implantation in rainbow trout. Sci Rep 2020; 10:5583. [PMID: 32221366 PMCID: PMC7101407 DOI: 10.1038/s41598-020-62558-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Accepted: 03/09/2020] [Indexed: 11/09/2022] Open
Abstract
Bio-logging devices can provide unique insights on the life of freely moving animals. However, implanting these devices often requires invasive surgery that causes stress and physiological side-effects. While certain medications in connection to surgeries have therapeutic capacity, others may have aversive effects. Here, we hypothesized that the commonly prescribed prophylactic treatment with enrofloxacin would increase the physiological recovery rate and reduce the presence of systemic inflammation following the intraperitoneal implantation of a heart rate bio-logger in rainbow trout (Oncorhynchus mykiss). To assess post-surgical recovery, heart rate was recorded for 21 days in trout with or without enrofloxacin treatment. Contrary to our hypothesis, treated trout exhibited a prolonged recovery time and elevated resting heart rates during the first week of post-surgical recovery compared to untreated trout. In addition, an upregulated mRNA expression of TNFα in treated trout indicate a possible inflammatory response 21 days post-surgery. Interestingly, the experience level of the surgeon was observed to have a long-lasting impact on heart rate. In conclusion, our study showed no favorable effects of enrofloxacin treatment. Our findings highlight the importance of adequate post-surgical recovery times and surgical training with regards to improving the welfare of experimental animals and reliability of research outcomes.
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Affiliation(s)
- Per Hjelmstedt
- Department of Animal Environment and Health, Swedish University of Agricultural Sciences, Skara, SE-532 31, Sweden.
| | - Henrik Sundh
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, SE-405-30, Sweden.,Swedish Mariculture Research Center, Centre for Sea and Society at University of Gothenburg, Gothenburg, SE-405-30, Sweden
| | - Jeroen Brijs
- Department of Animal Environment and Health, Swedish University of Agricultural Sciences, Skara, SE-532 31, Sweden
| | - Andreas Ekström
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, SE-405-30, Sweden
| | - Kristina Snuttan Sundell
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, SE-405-30, Sweden.,Swedish Mariculture Research Center, Centre for Sea and Society at University of Gothenburg, Gothenburg, SE-405-30, Sweden
| | - Charlotte Berg
- Department of Animal Environment and Health, Swedish University of Agricultural Sciences, Skara, SE-532 31, Sweden
| | - Erik Sandblom
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, SE-405-30, Sweden
| | - Jennifer Bowman
- Department of Animal Environment and Health, Swedish University of Agricultural Sciences, Skara, SE-532 31, Sweden
| | - Daniel Morgenroth
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, SE-405-30, Sweden
| | - Albin Gräns
- Department of Animal Environment and Health, Swedish University of Agricultural Sciences, Skara, SE-532 31, Sweden
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10
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Semple SL, Bols NC, Lumsden JS, Dixon B. Understanding the pathogenesis of Flavobacterium psychrophilum using the rainbow trout monocyte/macrophage-like cell line, RTS11, as an infection model. Microb Pathog 2019; 139:103910. [PMID: 31809795 DOI: 10.1016/j.micpath.2019.103910] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Revised: 11/28/2019] [Accepted: 12/02/2019] [Indexed: 02/05/2023]
Abstract
The life cycle of Flavobacterium psychrophilum (Fp), the causative agent of bacterial coldwater disease (BCWD) and rainbow trout fry syndrome (RTFS), appears to involve interactions with spleen and head kidney macrophages. To develop an in vitro model for studying this, F. psychrophilum was incubated with a rainbow trout splenic monocyte/macrophage-like cell line (RTS11) and fundamental macrophage functions evaluated. The animal cell basal medium, L15, supplemented with bovine serum (FBS) supports RTS11 maintenance, and surprisingly, L15 with 2% FBS (L15/FBS) also supported F. psychrophilum growth. L15/FBS in which the bacteria had been grown is referred to as F. psychrophilum conditioned medium (FpCM). Adding FpCM to RTS11 cultures caused a small, yet significant, percentage of cells to die, many cells to become more diffuse, and phagocytosis to be temporarily reduced. FpCM also significantly stimulated transcript expression for pro-inflammatory cytokines (IL-1β, TNFα and IL-6) and the anti-inflammatory cytokine (IL-10) after one day of exposure but this upregulation rapidly declined over time. Adding live F. psychrophilum to RTS11 cultures also altered the cellular morphology and stimulated cytokine expression more profoundly than FpCM. Additionally, the phagocytic activity of RTS11 was also significantly impaired by live F. psychrophilum, but not to the same extent as when exposed to FpCM. Adding heat-killed bacteria to RTS11 cultures elicited few changes. These bacteria/RTS11 co-cultures should be useful for gaining a deeper understanding of the pathogenesis of F. psychrophilum and may aid in the development of effective measures to prevent infection and spread of this troublesome disease.
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Affiliation(s)
- Shawna L Semple
- University of Waterloo, Department of Biology, Waterloo, Canada
| | - Niels C Bols
- University of Waterloo, Department of Biology, Waterloo, Canada
| | - John S Lumsden
- University of Guelph, Ontario Veterinary College, Department of Pathobiology, Guelph, Canada
| | - Brian Dixon
- University of Waterloo, Department of Biology, Waterloo, Canada.
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11
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Semple SL, Heath G, Christie D, Braunstein M, Kales SC, Dixon B. Immune stimulation of rainbow trout reveals divergent regulation of MH class II-associated invariant chain isoforms. Immunogenetics 2019; 71:407-420. [PMID: 31037384 DOI: 10.1007/s00251-019-01115-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2018] [Accepted: 04/06/2019] [Indexed: 12/20/2022]
Abstract
Major histocompatibility complex (MHC) class II-associated invariant chain is a chaperone responsible for targeting the MHC class II dimer to the endocytic pathway, thus enabling the loading of exogenous antigens onto the MHC class II receptor. In the current study, in vivo and in vitro methods were used to investigate the regulation of the rainbow trout invariant chain proteins S25-7 and INVX, upon immune system activation. Whole rainbow trout and the macrophage/monocyte-like cell line RTS11 were treated with PMA at concentrations shown to induce IL-1β transcripts and homotypic aggregation of RTS11. S25-7 transcript levels remained unchanged in the gill, spleen, and liver and were found to be significantly decreased in head kidney beginning 24 h post-stimulation. Meanwhile, INVX transcript levels remained unchanged in all tissues studied. Both S25-7 and INVX proteins were produced in gill and spleen tissues but their expression was unaffected by immune system stimulation. Surprisingly, neither INVX nor S25-7 protein was detected in the secondary immune organ, the head kidney. Analysis of RTS11 cultures demonstrated that both INVX and S25-7 transcript levels significantly increased at 96 h and 120 h following PMA stimulation before returning to control levels at 168 h. Meanwhile, at the protein level in RTS11, S25-7 remained unchanged while INVX had a significant decrease at 168 h post-stimulation. These results indicate that neither INVX nor S25-7 is upregulated upon immune system activation; thus, teleosts have evolved a system of immune regulation that is different than that found in mammals.
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Affiliation(s)
- Shawna L Semple
- Department of Biology, University of Waterloo, 200 University Ave W., Waterloo, ON, N2L 3G1, Canada
| | - George Heath
- Department of Biology, University of Waterloo, 200 University Ave W., Waterloo, ON, N2L 3G1, Canada
| | - Darah Christie
- Department of Biology, University of Waterloo, 200 University Ave W., Waterloo, ON, N2L 3G1, Canada
| | - Marsela Braunstein
- Department of Biology, University of Waterloo, 200 University Ave W., Waterloo, ON, N2L 3G1, Canada
| | - Stephen C Kales
- Department of Biology, University of Waterloo, 200 University Ave W., Waterloo, ON, N2L 3G1, Canada
| | - Brian Dixon
- Department of Biology, University of Waterloo, 200 University Ave W., Waterloo, ON, N2L 3G1, Canada.
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12
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Semple SL, Rodríguez-Ramos T, Carpio Y, Lumsden JS, Estrada MP, Dixon B. PACAP Is Lethal to Flavobacterium psychrophilum Through Either Direct Membrane Permeabilization or Indirectly, by Priming the Immune Response in Rainbow Trout Macrophages. Front Immunol 2019; 10:926. [PMID: 31105711 PMCID: PMC6498415 DOI: 10.3389/fimmu.2019.00926] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2019] [Accepted: 04/10/2019] [Indexed: 01/26/2023] Open
Abstract
Pituitary adenylate cyclase-activating polypeptide (PACAP) is a multifunctional neuropeptide that is widely distributed in mammals and is capable of performing roles as a neurotransmitter, neuromodulator, and vasodilator. This polypeptide belongs to the glucagon/secretin superfamily, of which some members have been shown to act as antimicrobial peptides in both mammalian and aquatic organisms. In teleosts, PACAP has been demonstrated to have direct antimicrobial activity against several aquatic pathogens, yet this phenomenon has never been studied throughout a live bacterial challenge. The present study focuses on the influence of synthetic Clarias gariepinus 38 amino acid PACAP on the rainbow trout monocyte/macrophage-like cell line, RTS11, when exposed to the coldwater bacterial pathogen Flavobacterium psychrophilum. PACAP was shown to have direct antimicrobial activity on F. psychrophilum when grown in both cytophaga broth and cell culture media (L-15). Further, the ability of teleostean PACAP to permeabilize the membrane of an aquatic pathogen, F. psychrophilum, was demonstrated for the first time. The viability of RTS11 when exposed to PACAP was also observed using a trypan blue exclusion assay to determine optimal experimental doses of the antimicrobial peptide. This displayed that only concentrations higher than 0.1 μM negatively impacted RTS11 survival. Interestingly, when RTS11 was pre-treated with PACAP for 24 h before experiencing infection with live F. psychrophilum, growth of the pathogen was severely inhibited in a dose-dependent manner when compared to cells receiving no pre-treatment with the polypeptide. Relative expression of pro-inflammatory cytokines (IL-1β, TNFα, and IL-6) and PACAP receptors (VPAC1 and PAC1) was also analyzed in RTS11 following PACAP exposure alone and in conjunction with live F. psychrophilum challenge. These qRT-PCR findings revealed that PACAP may have a synergistic effect on RTS11 immune function. The results of this study provide evidence that PACAP has immunostimulatory activity on rainbow trout immune cells as well as antimicrobial activity against aquatic bacterial pathogens such as F. psychrophilum. As there are numerous pathogens that plague the aquaculture industry, PACAP may stimulate the teleost immune system while also providing an efficacious alternative to antibiotic use.
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Affiliation(s)
- Shawna L Semple
- Department of Biology, University of Waterloo, Waterloo, ON, Canada
| | | | - Yamila Carpio
- Center for Genetic Engineering and Biotechnology, Havana, Cuba
| | - John S Lumsden
- Department of Pathobiology, Ontario Veterinary College, University of Guelph, Guelph, ON, Canada
| | - Mario P Estrada
- Center for Genetic Engineering and Biotechnology, Havana, Cuba
| | - Brian Dixon
- Department of Biology, University of Waterloo, Waterloo, ON, Canada
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