1
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Wyber BW, Tomkins JL, Simmons LW. No evidence for an up-regulation of female immune function in response to elevated risk of sexual conflict. Biol Lett 2024; 20:20240141. [PMID: 39226921 PMCID: PMC11371421 DOI: 10.1098/rsbl.2024.0141] [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: 03/19/2024] [Revised: 05/21/2024] [Accepted: 07/08/2024] [Indexed: 09/05/2024] Open
Abstract
Sexual conflict is widespread among sexually reproducing organisms. Phenotypic plasticity in female resistance traits has the potential to moderate the harm imposed by males during mating, yet female plasticity has rarely been explored. In this experiment, we investigated whether female seed beetles invest more in immunocompetence, measured as phenoloxidase (PO) capacity, when exposed to cues signalling a greater risk of sexual conflict. Risk perception was manipulated by housing focal individuals alone or with a companion as developing larvae, followed by exposure to a mating-free male- or female-biased social environment when adults. We predicted that females exposed to cues of increased sexual conflict would have increased PO capacity. However, PO capacity did not differ between either larval or adult social treatments. Our results suggest that females may not perceive a risk to their fitness on the basis of increased male presence or are unable to adjust this aspect of their phenotype in response to that risk.
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Affiliation(s)
- Blake W. Wyber
- Centre for Evolutionary Biology, School of Biological Sciences, The University of Western Australia, Crawley6009, Australia
| | - Joseph L. Tomkins
- Centre for Evolutionary Biology, School of Biological Sciences, The University of Western Australia, Crawley6009, Australia
| | - Leigh W. Simmons
- Centre for Evolutionary Biology, School of Biological Sciences, The University of Western Australia, Crawley6009, Australia
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2
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Goerlinger A, Develay C, Balourdet A, Rigaud T, Moret Y. Infection risk by oral contamination does not induce immune priming in the mealworm beetle ( Tenebrio molitor) but triggers behavioral and physiological responses. Front Immunol 2024; 15:1354046. [PMID: 38404577 PMCID: PMC10885348 DOI: 10.3389/fimmu.2024.1354046] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2023] [Accepted: 01/29/2024] [Indexed: 02/27/2024] Open
Abstract
In invertebrates, immune priming is the ability of individuals to enhance their immune response based on prior immunological experiences. This adaptive-like immunity likely evolved due to the risk of repeated infections by parasites in the host's natural habitat. The expression of immune priming varies across host and pathogen species, as well as infection routes (oral or wounds), reflecting finely tuned evolutionary adjustments. Evidence from the mealworm beetle (Tenebrio molitor) suggests that Gram-positive bacterial pathogens play a significant role in immune priming after systemic infection. Despite the likelihood of oral infections by natural bacterial pathogens in T. molitor, it remains debated whether ingestion of contaminated food leads to systemic infection, and whether oral immune priming is possible is currently unknown. We first attempted to induce immune priming in both T. molitor larvae and adults by exposing them to food contaminated with living or dead Gram-positive and Gram-negative bacterial pathogens. We found that oral ingestion of living bacteria did not kill them, but septic wounds caused rapid mortality. Intriguingly, the consumption of either dead or living bacteria did not protect against reinfection, contrasting with injury-induced priming. We further examined the effects of infecting food with various living bacterial pathogens on variables such as food consumption, mass gain, and feces production in larvae. We found that larvae exposed to Gram-positive bacteria in their food ingested less food, gained less mass and/or produced more feces than larvae exposed to contaminated food with Gram-negative bacteria or control food. This suggests that oral contamination with Gram-positive bacteria induced both behavioral responses and peristalsis defense mechanisms, even though no immune priming was observed here. Considering that the oral route of infection neither caused the death of the insects nor induced priming, we propose that immune priming in T. molitor may have primarily evolved as a response to the infection risk associated with wounds rather than oral ingestion.
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Affiliation(s)
| | | | | | | | - Yannick Moret
- CNRS UMR 6282 Biogéosciences, Université de Bourgogne, Dijon, France
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3
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Somé BM, Guissou E, Da DF, Richard Q, Choisy M, Yameogo KB, Hien DF, Yerbanga RS, Ouedraogo GA, Dabiré KR, Djidjou-Demasse R, Cohuet A, Lefèvre T. Mosquito ageing modulates the development, virulence and transmission potential of pathogens. Proc Biol Sci 2024; 291:20232097. [PMID: 38166422 PMCID: PMC10762442 DOI: 10.1098/rspb.2023.2097] [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: 09/15/2023] [Accepted: 11/27/2023] [Indexed: 01/04/2024] Open
Abstract
Host age variation is a striking source of heterogeneity that can shape the evolution and transmission dynamic of pathogens. Compared with vertebrate systems, our understanding of the impact of host age on invertebrate-pathogen interactions remains limited. We examined the influence of mosquito age on key life-history traits driving human malaria transmission. Females of Anopheles coluzzii, a major malaria vector, belonging to three age classes (4-, 8- and 12-day-old), were experimentally infected with Plasmodium falciparum field isolates. Our findings revealed reduced competence in 12-day-old mosquitoes, characterized by lower oocyst/sporozoite rates and intensities compared with younger mosquitoes. Despite shorter median longevities in older age classes, infected 12-day-old mosquitoes exhibited improved survival, suggesting that the infection might act as a fountain of youth for older mosquitoes specifically. The timing of sporozoite appearance in the salivary glands remained consistent across mosquito age classes, with an extrinsic incubation period of approximately 13 days. Integrating these results into an epidemiological model revealed a lower vectorial capacity for older mosquitoes compared with younger ones, albeit still substantial owing to extended longevity in the presence of infection. Considering age heterogeneity provides valuable insights for ecological and epidemiological studies, informing targeted control strategies to mitigate pathogen transmission.
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Affiliation(s)
- Bernard M. Somé
- Unité Paludisme et Maladies Tropicales Négligées, Institut de Recherche en Sciences de la Santé (IRSS), 01 BP 545 Bobo Dioulasso, Burkina Faso
- Laboratoire Mixte International sur les Vecteurs (LAMIVECT), Bobo Dioulasso, Burkina Faso
- Département de Biochimie, Université Nazi Boni, 01 BP 1091 Bobo Dioulasso, Burkina Faso
| | - Edwige Guissou
- Unité Paludisme et Maladies Tropicales Négligées, Institut de Recherche en Sciences de la Santé (IRSS), 01 BP 545 Bobo Dioulasso, Burkina Faso
- Laboratoire Mixte International sur les Vecteurs (LAMIVECT), Bobo Dioulasso, Burkina Faso
- Département de Biochimie, Université Nazi Boni, 01 BP 1091 Bobo Dioulasso, Burkina Faso
- MIVEGEC, IRD, CNRS, University of Montpellier, 34090 Montpellier cedex 5, France
- Ecole Normale Supérieure, BP 376 Koudougou, Burkina Faso
| | - Dari F. Da
- Unité Paludisme et Maladies Tropicales Négligées, Institut de Recherche en Sciences de la Santé (IRSS), 01 BP 545 Bobo Dioulasso, Burkina Faso
| | - Quentin Richard
- IMAG, Université de Montpellier, CNRS, 34090 Montpellier, France
| | - Marc Choisy
- Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, 700000, Ho Chi Minh City, Vietnam
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford OX3 7BN, UK
| | - Koudraogo B. Yameogo
- Unité Paludisme et Maladies Tropicales Négligées, Institut de Recherche en Sciences de la Santé (IRSS), 01 BP 545 Bobo Dioulasso, Burkina Faso
- Laboratoire Mixte International sur les Vecteurs (LAMIVECT), Bobo Dioulasso, Burkina Faso
| | - Domombabele FdS. Hien
- Unité Paludisme et Maladies Tropicales Négligées, Institut de Recherche en Sciences de la Santé (IRSS), 01 BP 545 Bobo Dioulasso, Burkina Faso
- Laboratoire Mixte International sur les Vecteurs (LAMIVECT), Bobo Dioulasso, Burkina Faso
| | - Rakiswende S. Yerbanga
- Unité Paludisme et Maladies Tropicales Négligées, Institut de Recherche en Sciences de la Santé (IRSS), 01 BP 545 Bobo Dioulasso, Burkina Faso
- Laboratoire Mixte International sur les Vecteurs (LAMIVECT), Bobo Dioulasso, Burkina Faso
| | - Georges A. Ouedraogo
- Département de Biochimie, Université Nazi Boni, 01 BP 1091 Bobo Dioulasso, Burkina Faso
| | - Kounbobr R. Dabiré
- Unité Paludisme et Maladies Tropicales Négligées, Institut de Recherche en Sciences de la Santé (IRSS), 01 BP 545 Bobo Dioulasso, Burkina Faso
- Laboratoire Mixte International sur les Vecteurs (LAMIVECT), Bobo Dioulasso, Burkina Faso
| | | | - Anna Cohuet
- Laboratoire Mixte International sur les Vecteurs (LAMIVECT), Bobo Dioulasso, Burkina Faso
- MIVEGEC, IRD, CNRS, University of Montpellier, 34090 Montpellier cedex 5, France
| | - Thierry Lefèvre
- Unité Paludisme et Maladies Tropicales Négligées, Institut de Recherche en Sciences de la Santé (IRSS), 01 BP 545 Bobo Dioulasso, Burkina Faso
- Laboratoire Mixte International sur les Vecteurs (LAMIVECT), Bobo Dioulasso, Burkina Faso
- MIVEGEC, IRD, CNRS, University of Montpellier, 34090 Montpellier cedex 5, France
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4
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Zhou SO, Arunkumar R, Irfan A, Ding SD, Leitão AB, Jiggins FM. The evolution of constitutively active humoral immune defenses in Drosophila populations under high parasite pressure. PLoS Pathog 2024; 20:e1011729. [PMID: 38206983 PMCID: PMC10807768 DOI: 10.1371/journal.ppat.1011729] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2023] [Revised: 01/24/2024] [Accepted: 01/04/2024] [Indexed: 01/13/2024] Open
Abstract
Both constitutive and inducible immune mechanisms are employed by hosts for defense against infection. Constitutive immunity allows for a faster response, but it comes with an associated cost that is always present. This trade-off between speed and fitness costs leads to the theoretical prediction that constitutive immunity will be favored where parasite exposure is frequent. We selected populations of Drosophila melanogaster under high parasite pressure from the parasitoid wasp Leptopilina boulardi. With RNA sequencing, we found the evolution of resistance in these populations was associated with them developing constitutively active humoral immunity, mediated by the larval fat body. Furthermore, these evolved populations were also able to induce gene expression in response to infection to a greater level, which indicates an overall more activated humoral immune response to parasitization. The anti-parasitoid immune response also relies on the JAK/STAT signaling pathway being activated in muscles following infection, and this induced response was only seen in populations that had evolved under high parasite pressure. We found that the cytokine Upd3, which induces this JAK/STAT response, is being expressed by immature lamellocytes. Furthermore, these immune cells became constitutively present when populations evolved resistance, potentially explaining why they gained the ability to activate JAK/STAT signaling. Thus, under intense parasitism, populations evolved resistance by increasing both constitutive and induced immune defenses, and there is likely an interplay between these two forms of immunity.
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Affiliation(s)
- Shuyu Olivia Zhou
- Department of Genetics, University of Cambridge, Cambridge, United Kingdom
| | - Ramesh Arunkumar
- Section of population genetics, School of Life Sciences, Technical University of Munich, Freising, Germany
| | - Amina Irfan
- Department of Genetics, University of Cambridge, Cambridge, United Kingdom
| | | | - Alexandre B. Leitão
- Champalimaud Foundation, Champalimaud Centre of the Unknown, Lisbon, Portugal
| | - Francis M. Jiggins
- Department of Genetics, University of Cambridge, Cambridge, United Kingdom
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5
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Tang L, Qiu W, Zhang S, Wang J, Yang X, Xu B, Magnuson JT, Xu EG, Wu M, Zheng C. Poly- and Perfluoroalkyl Substances Induce Immunotoxicity via the TLR Pathway in Zebrafish: Links to Carbon Chain Length. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:6139-6149. [PMID: 37017313 DOI: 10.1021/acs.est.2c09716] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
Previous studies have reported the immunotoxicity of per- and polyfluoroalkyl substances (PFASs), but it remains a significant challenge to assess over 10,000 distinct PFASs registered in the distributed structure-searchable toxicity (DSSTox) database. We aim to reveal the mechanisms of immunotoxicity of different PFASs and hypothesize that PFAS immunotoxicity is dependent on the carbon chain length. Perfluorobutanesulfonic acid (PFBA), perfluorooctanoic acid (PFOA), and perfluorononanoic acid (PFNA) representing different carbon chain lengths (4-9) at environmentally relevant levels strongly reduced the host's antibacterial ability during the zebrafish's early-life stage. Innate and adaptive immunities were both suppressed after PFAS exposures, exhibiting a significant induction of macrophages and neutrophils and expression of immune-related genes and indicators. Interestingly, the PFAS-induced immunotoxic responses were positively correlated to the carbon chain length. Moreover, PFASs activated downstream genes of the toll-like receptor (TLR), uncovering a seminal role of TLR in PFAS immunomodulatory effects. Myeloid differentiation factor 88 (MyD88) morpholino knock-down experiments and MyD88 inhibitors alleviated the immunotoxicity of PFASs. Overall, the comparative results demonstrate differences in the immunotoxic responses of PFASs due to carbon chain length in zebrafish, providing new insights into the prediction and classification of PFASs mode of toxic action based on carbon chain length.
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Affiliation(s)
- Liang Tang
- Key Laboratory of Organic Compound Pollution Control Engineering (MOE), School of Environmental and Chemical Engineering, Shanghai University, Shanghai 200444, China
| | - Wenhui Qiu
- Guangdong Provincial Key Laboratory of Soil and Groundwater Pollution Control, School of Environmental Science and Engineering, Southern University of Science and Technology, 1088 Xueyuan Avenue, Nanshan District, Shenzhen 518055, China
| | - Shuwen Zhang
- Guangdong Provincial Key Laboratory of Soil and Groundwater Pollution Control, School of Environmental Science and Engineering, Southern University of Science and Technology, 1088 Xueyuan Avenue, Nanshan District, Shenzhen 518055, China
| | - Jiazhen Wang
- Guangdong Provincial Key Laboratory of Soil and Groundwater Pollution Control, School of Environmental Science and Engineering, Southern University of Science and Technology, 1088 Xueyuan Avenue, Nanshan District, Shenzhen 518055, China
| | - Xin Yang
- Shenzhen Key Laboratory of Precision Measurement and Early Warning Technology for Urban Environmental Health Risks, School of Environmental Science and Engineering, Southern University of Science and Technology, 1088 Xueyuan Avenue, Nanshan District, Shenzhen 518055, China
| | - Bentuo Xu
- National and Local Joint Engineering Research Center of Ecological Treatment Technology for Urban Water Pollution, School of Life and Environmental Science, Wenzhou University, Chashan University Town, Wenzhou 325035, China
| | - Jason T Magnuson
- Department of Chemistry, Bioscience and Environmental Engineering, University of Stavanger, Måltidets Hus - Richard Johnsens gate 4, Stavanger 4021, Norway
| | - Elvis Genbo Xu
- Department of Biology, University of Southern Denmark, Campusvej 55, Odense 5230, Denmark
| | - Minghong Wu
- Key Laboratory of Organic Compound Pollution Control Engineering (MOE), School of Environmental and Chemical Engineering, Shanghai University, Shanghai 200444, China
| | - Chunmiao Zheng
- Guangdong Provincial Key Laboratory of Soil and Groundwater Pollution Control, School of Environmental Science and Engineering, Southern University of Science and Technology, 1088 Xueyuan Avenue, Nanshan District, Shenzhen 518055, China
- EIT Institute for Advanced Study, 568 Tongxin Road, Zhenhai District, Ningbo 315410, China
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6
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Ferguson LV, Adamo SA. From perplexing to predictive: are we ready to forecast insect disease susceptibility in a warming world? J Exp Biol 2023; 226:288412. [PMID: 36825944 DOI: 10.1242/jeb.244911] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/25/2023]
Abstract
Insects are critical to our ecosystems, but we do not fully understand their future in our warming world. Rising temperatures are affecting insect physiology in myriad ways, including changes to their immune systems and the ability to fight infection. Whether predicted changes in temperature will contribute to insect mortality or success, and the role of disease in their future survival, remains unclear. Although heat can enhance immunity by activating the integrated defense system (e.g. via the production of protective molecules such as heat-shock proteins) and accelerating enzyme activity, heat can also compromise the immune system through energetic-resource trade-offs and damage. The responses to heat are highly variable among species. The reasons for this variability are poorly known, and we are lagging in our understanding of how and why the immune system responds to changes in temperature. In this Commentary, we highlight the variation in insect immune responses to heat and the likely underlying mechanisms. We suggest that we are currently limited in our ability to predict the effects of rising temperatures on insect immunity and disease susceptibility, largely owing to incomplete information, coupled with a lack of tools for data integration. Moreover, existing data are concentrated on a relatively small number of insect Orders. We provide suggestions for a path towards making more accurate predictions, which will require studies with realistic temperature exposures and housing design, and a greater understanding of both the thermal biology of the immune system and connections between immunity and the physiological responses to heat.
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Affiliation(s)
- Laura V Ferguson
- Department of Biology, Acadia University, Wolfville, NS B4P 2R6, Canada
| | - Shelley A Adamo
- Department of Psychology and Neuroscience, Dalhousie University, Halifax, NS B3H 4R2, Canada
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7
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Field EK, Hartzheim A, Terry J, Dawson G, Haydt N, Neuman-Lee LA. Reptilian Innate Immunology and Ecoimmunology: What Do We Know and Where Are We Going? Integr Comp Biol 2022; 62:1557-1571. [PMID: 35833292 DOI: 10.1093/icb/icac116] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Revised: 06/27/2022] [Accepted: 06/28/2022] [Indexed: 01/05/2023] Open
Abstract
Reptiles, the only ectothermic amniotes, employ a wide variety of physiological adaptations to adjust to their environments but remain vastly understudied in the field of immunology and ecoimmunology in comparison to other vertebrate taxa. To address this knowledge gap, we assessed the current state of research on reptilian innate immunology by conducting an extensive literature search of peer-reviewed articles published across the four orders of Reptilia (Crocodilia, Testudines, Squamata, and Rhynchocephalia). Using our compiled dataset, we investigated common techniques, characterization of immune components, differences in findings and type of research among the four orders, and immune responses to ecological and life-history variables. We found that there are differences in the types of questions asked and approaches used for each of these reptilian orders. The different conceptual frameworks applied to each group has led to a lack of unified understanding of reptilian immunological strategies, which, in turn, have resulted in large conceptual gaps in the field of ecoimmunology as a whole. To apply ecoimmunological concepts and techniques most effectively to reptiles, we must combine traditional immunological studies with ecoimmunological studies to continue to identify, characterize, and describe the reptilian immune components and responses. This review highlights the advances and gaps that remain to help identify targeted and cohesive approaches for future research in reptilian ecoimmunological studies.
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Affiliation(s)
- Emily K Field
- Department of Biological Sciences, Arkansas State University, Jonesboro, AR 72401, USA
| | - Alyssa Hartzheim
- Department of Biological Sciences, Arkansas State University, Jonesboro, AR 72401, USA
| | - Jennifer Terry
- Department of Biological Sciences, Arkansas State University, Jonesboro, AR 72401, USA
| | - Grant Dawson
- Department of Biological Sciences, Arkansas State University, Jonesboro, AR 72401, USA
| | - Natalie Haydt
- Department of Biological Sciences, Arkansas State University, Jonesboro, AR 72401, USA
| | - Lorin A Neuman-Lee
- Department of Biological Sciences, Arkansas State University, Jonesboro, AR 72401, USA
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8
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Shit B, Prakash A, Sarkar S, Vale PF, Khan I. Ageing leads to reduced specificity of antimicrobial peptide responses in Drosophila melanogaster. Proc Biol Sci 2022; 289:20221642. [PMID: 36382522 PMCID: PMC9667363 DOI: 10.1098/rspb.2022.1642] [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: 08/20/2022] [Accepted: 10/24/2022] [Indexed: 11/17/2022] Open
Abstract
Evolutionary theory predicts a late-life decline in the force of natural selection, possibly leading to late-life deregulations of the immune system. A potential outcome of such deregulations is the inability to produce specific immunity against target pathogens. We tested this possibility by infecting multiple Drosophila melanogaster lines (with bacterial pathogens) across age groups, where either individual or different combinations of Imd- and Toll-inducible antimicrobial peptides (AMPs) were deleted using CRISPR gene editing. We show a high degree of non-redundancy and pathogen-specificity of AMPs in young flies: in some cases, even a single AMP could confer complete resistance. However, ageing led to drastic reductions in such specificity to target pathogens, warranting the action of multiple AMPs across Imd and Toll pathways. Moreover, use of diverse AMPs either lacked survival benefits or even accompanied survival costs post-infection. These features were also sexually dimorphic: females required a larger repertoire of AMPs than males but extracted equivalent survival benefits. Finally, age-specific expansion of the AMP-repertoire was accompanied with ageing-induced downregulation of negative-regulators of the Imd pathway and damage to renal function post-infection, as features of poorly regulated immunity. Overall, we could highlight the potentially non-adaptive role of ageing in producing less-specific AMP responses, across sexes and pathogens.
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Affiliation(s)
- Biswajit Shit
- Ashoka University, Plot No. 2, Rajiv Gandhi Education City, National Capital Region P.O. Rai, Sonepat, Haryana-131029, India
| | - Arun Prakash
- Institute of Ecology and Evolution, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3FL, UK
| | - Saubhik Sarkar
- Ashoka University, Plot No. 2, Rajiv Gandhi Education City, National Capital Region P.O. Rai, Sonepat, Haryana-131029, India
| | - Pedro F. Vale
- Institute of Ecology and Evolution, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3FL, UK
| | - Imroze Khan
- Ashoka University, Plot No. 2, Rajiv Gandhi Education City, National Capital Region P.O. Rai, Sonepat, Haryana-131029, India
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9
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Jehan C, Sabarly C, Rigaud T, Moret Y. Senescence of the immune defences and reproductive trade-offs in females of the mealworm beetle, Tenebrio molitor. Sci Rep 2022; 12:19747. [PMID: 36396809 PMCID: PMC9671880 DOI: 10.1038/s41598-022-24334-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Accepted: 11/14/2022] [Indexed: 11/18/2022] Open
Abstract
In the theory of ageing, it has been assumed that ageing is associated with a decline in somatic defences, including the immune system, as a consequence of a trade-off with reproduction. While overall immunity suffers from age-related deterioration (immune senescence), the different components of the immune response appear to age differently. It is also likely that investment among the many arms of the immune system and reproduction with age is finely adjusted to the organisms' reproductive strategy. We investigated this possibility in females of Tenebrio molitor, a species of long-lived insect with reproductive strategies similar to those of long-lived mammals. We specifically tested the effects of immunological challenges imposed early or late in adult life on immune pathway activation as well as fertility early and late in life. We found complex patterns of changes in immune defences with age and age-specific immune challenges with contrasted relationships with female reproduction. While cellular and enzymatic defences showed signs of ageing, they did not trade-off with reproduction. By contrast, the induced antibacterial immune response was found to be unaffected by age and to be highly connected to female fecundity. These findings suggest that these immunological pathways have different functions with regard to female ageing in this insect species.
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Affiliation(s)
- Charly Jehan
- Laboratoire BioGéoSciences, UMR CNRS 6282, Équipe Écologie Évolutive, Université Bourgogne-Franche Comté, 6 Boulevard Gabriel, 21000, Dijon, France
| | - Camille Sabarly
- Laboratoire BioGéoSciences, UMR CNRS 6282, Équipe Écologie Évolutive, Université Bourgogne-Franche Comté, 6 Boulevard Gabriel, 21000, Dijon, France
| | - Thierry Rigaud
- Laboratoire BioGéoSciences, UMR CNRS 6282, Équipe Écologie Évolutive, Université Bourgogne-Franche Comté, 6 Boulevard Gabriel, 21000, Dijon, France
| | - Yannick Moret
- Laboratoire BioGéoSciences, UMR CNRS 6282, Équipe Écologie Évolutive, Université Bourgogne-Franche Comté, 6 Boulevard Gabriel, 21000, Dijon, France.
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10
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Decomposing virulence to understand bacterial clearance in persistent infections. Nat Commun 2022; 13:5023. [PMID: 36028497 PMCID: PMC9418333 DOI: 10.1038/s41467-022-32118-1] [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: 10/29/2021] [Accepted: 07/15/2022] [Indexed: 11/08/2022] Open
Abstract
Following an infection, hosts cannot always clear the pathogen, instead either dying or surviving with a persistent infection. Such variation is ecologically and evolutionarily important because it can affect infection prevalence and transmission, and virulence evolution. However, the factors causing variation in infection outcomes, and the relationship between clearance and virulence are not well understood. Here we show that sustained persistent infection and clearance are both possible outcomes across bacterial species showing a range of virulence in Drosophila melanogaster. Variation in virulence arises because of differences in the two components of virulence: bacterial infection intensity inside the host (exploitation), and the amount of damage caused per bacterium (per parasite pathogenicity). As early-phase exploitation increased, clearance rates later in the infection decreased, whereas there was no apparent effect of per parasite pathogenicity on clearance rates. Variation in infection outcomes is thereby determined by how virulence - and its components - relate to the rate of pathogen clearance. Taken together we demonstrate that the virulence decomposition framework is broadly applicable and can provide valuable insights into host-pathogen interactions.
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11
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Lazzaro BP, Tate AT. Balancing sensitivity, risk, and immunopathology in immune regulation. CURRENT OPINION IN INSECT SCIENCE 2022; 50:100874. [PMID: 35051619 PMCID: PMC9133098 DOI: 10.1016/j.cois.2022.100874] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2021] [Revised: 12/23/2021] [Accepted: 01/11/2022] [Indexed: 06/14/2023]
Abstract
Activation of an immune response is energetically costly and excessive immune system activity can result in immunopathology, yet a slow or insufficient immune response carries the risk of pathogen establishment with consequent pathology arising from the infection. Mathematical theory and empirical data demonstrate that hosts balance the costs of immunity against the risk of infection by closely regulating immunological dynamics. An optimal immune system is rapidly and robustly deployed against a true infectious threat and rapidly deactivated once the threat has been controlled. Genetic variation in the sensitivity of an immune system, as well as in the activation and shutdown kinetics of host immune responses, can contribute to the evolution of pathogen virulence and host tolerance of infection. Improved understanding of the adaptive forces that operate on immune regulatory dynamics will clarify fundamental principles governing the evolution and maintenance of innate immune systems.
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Affiliation(s)
- Brian P Lazzaro
- Departments of Entomology and Ecology & Evolutionary Biology, Cornell Institute of Host-Microbe Interactions and Disease, Cornell University, Ithaca, NY, USA.
| | - Ann T Tate
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA
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12
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Hund AK, Fuess LE, Kenney ML, Maciejewski MF, Marini JM, Shim KC, Bolnick DI. Population-level variation in parasite resistance due to differences in immune initiation and rate of response. Evol Lett 2022; 6:162-177. [PMID: 35386836 PMCID: PMC8966477 DOI: 10.1002/evl3.274] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Revised: 12/15/2021] [Accepted: 12/16/2021] [Indexed: 01/20/2023] Open
Abstract
Closely related populations often differ in resistance to a given parasite, as measured by infection success or failure. Yet, the immunological mechanisms of these evolved differences are rarely specified. Does resistance evolve via changes to the host's ability to recognize that an infection exists, actuate an effective immune response, or attenuate that response? We tested whether each of these phases of the host response contributed to threespine sticklebacks' recently evolved resistance to their tapeworm Schistocephalus solidus. Although marine stickleback and some susceptible lake fish permit fast-growing tapeworms, other lake populations are resistant and suppress tapeworm growth via a fibrosis response. We subjected lab-raised fish from three populations (susceptible marine "ancestors," a susceptible lake population, and a resistant lake population) to a novel immune challenge using an injection of (1) a saline control, (2) alum, a generalized pro-inflammatory adjuvant that causes fibrosis, (3) a tapeworm protein extract, or (4) a combination of alum and tapeworm protein. With enough time, all three populations generated a robust fibrosis response to the alum treatments. Yet, only the resistant population exhibited a fibrosis response to the tapeworm protein alone. Thus, these populations differed in their ability to respond to the tapeworm protein but shared an intact fibrosis pathway. The resistant population also initiated fibrosis faster in response to alum, and was able to attenuate fibrosis, unlike the susceptible populations' slow but longer lasting response to alum. As fibrosis has pathological side effects that reduce fecundity, the faster recovery by the resistant population may reflect an adaptation to mitigate the costs of immunity. Broadly, our results confirm that parasite detection and immune initiation, activation speed, and immune attenuation simultaneously contribute to the evolution of parasite resistance and adaptations to infection in natural populations.
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Affiliation(s)
- Amanda K. Hund
- Department of Ecology, Evolution, and BehaviorUniversity of MinnesotaSt. PaulMinnesota55123
| | - Lauren E. Fuess
- Department of Ecology and Evolutionary BiologyUniversity of ConnecticutStorrsConnecticut06269
- Current Address: Department of BiologyTexas State UniversitySan MarcosTexas78666
| | - Mariah L. Kenney
- Department of Ecology and Evolutionary BiologyUniversity of ConnecticutStorrsConnecticut06269
| | - Meghan F. Maciejewski
- Department of Ecology and Evolutionary BiologyUniversity of ConnecticutStorrsConnecticut06269
| | - Joseph M. Marini
- Department of Ecology and Evolutionary BiologyUniversity of ConnecticutStorrsConnecticut06269
| | - Kum Chuan Shim
- Department of Ecology, Evolution, and BehaviorUniversity of Texas at AustinAustinTexas78712
| | - Daniel I. Bolnick
- Department of Ecology and Evolutionary BiologyUniversity of ConnecticutStorrsConnecticut06269
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Prakash A, Khan I. Why do insects evolve immune priming? A search for crossroads. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2022; 126:104246. [PMID: 34453994 DOI: 10.1016/j.dci.2021.104246] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Accepted: 08/25/2021] [Indexed: 06/13/2023]
Abstract
Until recently, it was assumed that insects lack immune memory since they do not have vertebrate-like specialized memory cells. Therefore, their most well studied evolutionary response against pathogens was increased basal immunity. However, growing evidence suggests that many insects also exhibit a form of immune memory (immune priming), where prior exposure to a low dose of infection confers protection against subsequent infection by the same pathogen that acts both within and across generations. Most strikingly, they can rapidly evolve as a highly parallel and mutually exclusive strategy from basal immunity, under different selective conditions and with divergent evolutionary trade-offs. However, the relative importance of priming as an optimal immune strategy also has contradictions, primarily because supporting mechanisms are still unclear. In this review, we adopt a comparative approach to highlight several emerging evolutionary, ecological and mechanistic features of priming vs basal immune responses that warrant immediate attention for future research.
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Affiliation(s)
- Arun Prakash
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, EH9 3FL, United Kingdom.
| | - Imroze Khan
- Department of Biology, Ashoka University, Plot No. 2, Rajiv Gandhi Education City, P.O. Rai, Sonepat, Haryana, 131029, India.
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14
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Jehan C, Sabarly C, Rigaud T, Moret Y. Age-specific fecundity under pathogenic threat in an insect: Terminal investment versus reproductive restraint. J Anim Ecol 2021; 91:101-111. [PMID: 34626485 DOI: 10.1111/1365-2656.13604] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Accepted: 10/04/2021] [Indexed: 11/27/2022]
Abstract
The terminal investment hypothesis predicts that as an organism's prospects for survival decrease, through age or when exposed to a pathogenic infection, it will invest more in reproduction, which should trade-off against somatic maintenance (including immunity) and therefore future survival. Attempts to test this hypothesis have produced mixed results, which, in addition, mainly rely on the assessment of changes in reproductive effort and often overlooking its impact on somatic defences and survival. Alternatively, animals may restrain current reproduction to sustain somatic protection, increasing the chance of surviving for additional reproductive opportunities. We tested both of these hypotheses in females of the yellow mealworm beetle, Tenebrio molitor, an iteroparous insect with reproductive tactics similar to that of long-lived organisms. To achieve this, we mimicked pathogenic bacterial infections early or late in the life of breeding females by injecting them with a suspension of inactivated Bacillus cereus, a known natural pathogen of T. molitor, and measured female age-specific fecundity, survival, body mass and immunity. Inconsistent with a terminal investment, females given either an early or late-life immune challenge did not exhibit reduced survival or enhance their reproductive output. Female fecundity declined with age and was reduced by the early but not the late immune challenge. Both early and late-life fecundity correlated positively with life expectancy. Finally, young and old females exhibited similar antibacterial immune responses, suggesting that they both restrained reproduction to sustain immunity. Our results clearly demonstrate that age-specific reproduction of T. molitor females under pathogenic threat is inconsistent with a terminal investment. In contrast, our results instead suggest that females used a reproductive restraint strategy to sustain immunity and therefore subsequent reproductive opportunities. However, as infections were mimicked only, the fitness benefit of this reproductive restraint could not be shown.
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Affiliation(s)
- Charly Jehan
- UMR CNRS 6282 BioGéoSciences, Équipe Écologie Évolutive, Université Bourgogne-Franche Comté, Dijon, France
| | - Camille Sabarly
- UMR CNRS 6282 BioGéoSciences, Équipe Écologie Évolutive, Université Bourgogne-Franche Comté, Dijon, France
| | - Thierry Rigaud
- UMR CNRS 6282 BioGéoSciences, Équipe Écologie Évolutive, Université Bourgogne-Franche Comté, Dijon, France
| | - Yannick Moret
- UMR CNRS 6282 BioGéoSciences, Équipe Écologie Évolutive, Université Bourgogne-Franche Comté, Dijon, France
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15
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Seal S, Dharmarajan G, Khan I. Evolution of pathogen tolerance and emerging infections: A missing experimental paradigm. eLife 2021; 10:e68874. [PMID: 34544548 PMCID: PMC8455132 DOI: 10.7554/elife.68874] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Accepted: 08/23/2021] [Indexed: 12/11/2022] Open
Abstract
Researchers worldwide are repeatedly warning us against future zoonotic diseases resulting from humankind's insurgence into natural ecosystems. The same zoonotic pathogens that cause severe infections in a human host frequently fail to produce any disease outcome in their natural hosts. What precise features of the immune system enable natural reservoirs to carry these pathogens so efficiently? To understand these effects, we highlight the importance of tracing the evolutionary basis of pathogen tolerance in reservoir hosts, while drawing implications from their diverse physiological and life-history traits, and ecological contexts of host-pathogen interactions. Long-term co-evolution might allow reservoir hosts to modulate immunity and evolve tolerance to zoonotic pathogens, increasing their circulation and infectious period. Such processes can also create a genetically diverse pathogen pool by allowing more mutations and genetic exchanges between circulating strains, thereby harboring rare alive-on-arrival variants with extended infectivity to new hosts (i.e., spillover). Finally, we end by underscoring the indispensability of a large multidisciplinary empirical framework to explore the proposed link between evolved tolerance, pathogen prevalence, and spillover in the wild.
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Affiliation(s)
| | - Guha Dharmarajan
- Savannah River Ecology Laboratory, University of GeorgiaAikenUnited States
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16
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Bagchi B, Corbel Q, Khan I, Payne E, Banerji D, Liljestrand-Rönn J, Martinossi-Allibert I, Baur J, Sayadi A, Immonen E, Arnqvist G, Söderhäll I, Berger D. Sexual conflict drives micro- and macroevolution of sexual dimorphism in immunity. BMC Biol 2021; 19:114. [PMID: 34078377 PMCID: PMC8170964 DOI: 10.1186/s12915-021-01049-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Accepted: 05/07/2021] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND Sexual dimorphism in immunity is believed to reflect sex differences in reproductive strategies and trade-offs between competing life history demands. Sexual selection can have major effects on mating rates and sex-specific costs of mating and may thereby influence sex differences in immunity as well as associated host-pathogen dynamics. Yet, experimental evidence linking the mating system to evolved sexual dimorphism in immunity are scarce and the direct effects of mating rate on immunity are not well established. Here, we use transcriptomic analyses, experimental evolution and phylogenetic comparative methods to study the association between the mating system and sexual dimorphism in immunity in seed beetles, where mating causes internal injuries in females. RESULTS We demonstrate that female phenoloxidase (PO) activity, involved in wound healing and defence against parasitic infections, is elevated relative to males. This difference is accompanied by concomitant sex differences in the expression of genes in the prophenoloxidase activating cascade. We document substantial phenotypic plasticity in female PO activity in response to mating and show that experimental evolution under enforced monogamy (resulting in low remating rates and reduced sexual conflict relative to natural polygamy) rapidly decreases female (but not male) PO activity. Moreover, monogamous females had evolved increased tolerance to bacterial infection unrelated to mating, implying that female responses to costly mating may trade off with other aspects of immune defence, an hypothesis which broadly accords with the documented sex differences in gene expression. Finally, female (but not male) PO activity shows correlated evolution with the perceived harmfulness of male genitalia across 12 species of seed beetles, suggesting that sexual conflict has a significant influence on sexual dimorphisms in immunity in this group of insects. CONCLUSIONS Our study provides insights into the links between sexual conflict and sexual dimorphism in immunity and suggests that selection pressures moulded by mating interactions can lead to a sex-specific mosaic of immune responses with important implications for host-pathogen dynamics in sexually reproducing organisms.
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Affiliation(s)
- Basabi Bagchi
- Department of Biology, Ashoka University, Sonipat, India
| | - Quentin Corbel
- Department of Ecology and Genetics, Program of Animal Ecology, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden
- Cavanilles Institute of Biodiversity and Evolutionary Biology, University of Valencia, Valencia, Spain
| | - Imroze Khan
- Department of Biology, Ashoka University, Sonipat, India
| | - Ellen Payne
- Department of Ecology and Genetics, Program of Animal Ecology, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden
| | | | - Johanna Liljestrand-Rönn
- Department of Ecology and Genetics, Program of Animal Ecology, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden
| | - Ivain Martinossi-Allibert
- Department of Ecology and Genetics, Program of Animal Ecology, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden
- Department of Organismal Biology, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden
| | - Julian Baur
- Department of Ecology and Genetics, Program of Animal Ecology, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden
| | - Ahmed Sayadi
- Department of Ecology and Genetics, Program of Animal Ecology, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden
- Department of Chemistry, Biochemistry, Uppsala University, Uppsala, Sweden
| | - Elina Immonen
- Department of Ecology and Genetics, Program of Evolutionary Biology, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden
| | - Göran Arnqvist
- Department of Ecology and Genetics, Program of Animal Ecology, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden
| | - Irene Söderhäll
- Department of Organismal Biology, Program of Comparative Physiology, Uppsala University, Uppsala, Sweden
| | - David Berger
- Department of Ecology and Genetics, Program of Animal Ecology, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden.
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17
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Sheehan G, Margalit A, Sheehan D, Kavanagh K. Proteomic profiling of bacterial and fungal induced immune priming in Galleria mellonella larvae. JOURNAL OF INSECT PHYSIOLOGY 2021; 131:104213. [PMID: 33662378 DOI: 10.1016/j.jinsphys.2021.104213] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Revised: 02/19/2021] [Accepted: 02/24/2021] [Indexed: 06/12/2023]
Abstract
Some insects display immunological priming as a result of elevated humoral and cellular responses which give enhanced survival against subsequent infection. The humoral immune response of Galleria mellonella larvae following pre-exposure to heat killed Staphylococcus aureus or Candida albicans cells was determined by quantitative mass spectrometry in order to assess the relationship between the humoral immune response and resistance to subsequent bacterial or fungal infection. Larvae pre-exposed to heat killed S. aureus showed increased resistance to subsequent bacterial and fungal infection. Larvae displayed an increased hemocyte density (14.08 ± 2.14 × 106 larva-1 (p < 0.05) compared to the PBS injected control [10.41 ± 1.67 × 106 larva-1]) and increased abundance of antimicrobial proteins (cecropin-D-like peptide (+22.23 fold), hdd11 (+12.61 fold) and prophenol oxidase activating enzyme 3 (+5.96 fold) in response to heat killed S. aureus. Larvae pre-exposed to heat killed C. albicans cells were resistant to subsequent fungal infection but not bacterial infection and showed a reduced hemocyte density (6.01 ± 1.63 × 106 larva-1 (p < 0.01) and increased abundance of hdd11 (+32.73 fold) and moricin-like peptide C1 (+16.76 fold). While immune priming is well recognised in G. mellonella larvae the results presented here indicate distinct differences in the response of larvae following exposure to heat killed bacterial and fungal cells.
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Affiliation(s)
- Gerard Sheehan
- Department of Biology, Maynooth University, Maynooth, Co. Kildare, Ireland
| | - Anatte Margalit
- Department of Biology, Maynooth University, Maynooth, Co. Kildare, Ireland
| | - David Sheehan
- Department of Biology, Maynooth University, Maynooth, Co. Kildare, Ireland
| | - Kevin Kavanagh
- Department of Biology, Maynooth University, Maynooth, Co. Kildare, Ireland.
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18
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Kapila R, Kashyap M, Poddar S, Gangwal S, Prasad NGG. Evolution of pathogen-specific improved survivorship post-infection in populations of Drosophila melanogaster adapted to larval crowding. PLoS One 2021; 16:e0250055. [PMID: 33852596 PMCID: PMC8046209 DOI: 10.1371/journal.pone.0250055] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Accepted: 03/31/2021] [Indexed: 01/04/2023] Open
Abstract
The environment experienced by individuals during their juvenile stages has an impact on their adult stages. In holometabolous insects like Drosophila melanogaster, most of the resource acquisition for adult stages happens during the larval stages. Larval-crowding is a stressful environment, which exposes the larvae to scarcity of food and accumulation of toxic waste. Since adult traits are contingent upon larval stages, in larval-crowding like conditions, adult traits are prone to get affected. While the effect of resource limited, poor-developmental environment on adult immune response has been widely studied, the effect of adaptation to resource-limited developmental environment has not been studied, therefore in this study we assayed the evolution of ability to survive infection in adult stages as a correlated response to adaptation to larval crowding environments. Using four populations of Drosophila melanogaster adapted to larval crowding for 240 generations and their respective control populations, we show that populations adapted to larval crowding show an improved and evolved post-infection survivorship against a gram-negative bacteria Pseudomonas entomophila. Whereas, against a gram-positive bacteria Enterococcus faecalis, no difference in post-infection survivorship was observed across control and selected populations. In this study, we report the co-related evolution of pathogen-specific increased survivorship post-infection in populations of Drosophila melanogaster as a result of adaptation to larval crowding environment.
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Affiliation(s)
- Rohit Kapila
- Department of Biological Sciences, Indian Institute of Science Education and Research Mohali, Mohali, India
| | - Mayank Kashyap
- Department of Biological Sciences, Indian Institute of Science Education and Research Mohali, Mohali, India
| | - Soumyadip Poddar
- Department of Biological Sciences, Indian Institute of Science Education and Research Mohali, Mohali, India
| | - Shreya Gangwal
- Department of Biological Sciences, Indian Institute of Science Education and Research Mohali, Mohali, India
| | - N. G. G. Prasad
- Department of Biological Sciences, Indian Institute of Science Education and Research Mohali, Mohali, India
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19
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Hinshaw C, Evans KC, Rosa C, López-Uribe MM. The Role of Pathogen Dynamics and Immune Gene Expression in the Survival of Feral Honey Bees. Front Ecol Evol 2021. [DOI: 10.3389/fevo.2020.594263] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Studies of the ecoimmunology of feral organisms can provide valuable insight into how host–pathogen dynamics change as organisms transition from human-managed conditions back into the wild. Honey bees (Apis mellifera Linnaeus) offer an ideal system to investigate these questions as colonies of these social insects often escape management and establish in the wild. While managed honey bee colonies have low probability of survival in the absence of disease treatments, feral colonies commonly survive in the wild, where pathogen pressures are expected to be higher due to the absence of disease treatments. Here, we investigate the role of pathogen infections [Deformed wing virus (DWV), Black queen cell virus (BQCV), and Nosema ceranae] and immune gene expression (defensin-1, hymenoptaecin, pgrp-lc, pgrp-s2, argonaute-2, vago) in the survival of feral and managed honey bee colonies. We surveyed a total of 25 pairs of feral and managed colonies over a 2-year period (2017–2018), recorded overwintering survival, and measured pathogen levels and immune gene expression using quantitative polymerase chain reaction (qPCR). Our results showed that feral colonies had higher levels of DWV but it was variable over time compared to managed colonies. Higher pathogen levels were associated with increased immune gene expression, with feral colonies showing higher expression in five out of the six examined immune genes for at least one sampling period. Further analysis revealed that differential expression of the genes hymenoptaecin and vago increased the odds of overwintering survival in managed and feral colonies. Our results revealed that feral colonies express immune genes at higher levels in response to high pathogen burdens, providing evidence for the role of feralization in altering pathogen landscapes and host immune responses.
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20
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Gumiel M, de Mattos DP, Vieira CS, Moraes CS, Moreira CJDC, Gonzalez MS, Teixeira-Ferreira A, Waghabi M, Azambuja P, Carels N. Proteome of the Triatomine Digestive Tract: From Catalytic to Immune Pathways; Focusing on Annexin Expression. Front Mol Biosci 2020; 7:589435. [PMID: 33363206 PMCID: PMC7755933 DOI: 10.3389/fmolb.2020.589435] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Accepted: 10/21/2020] [Indexed: 12/15/2022] Open
Abstract
Rhodnius prolixus, Panstrongylus megistus, Triatoma infestans, and Dipetalogaster maxima are all triatomines and potential vectors of the protozoan Trypanosoma cruzi responsible for human Chagas' disease. Considering that the T. cruzi's cycle occurs inside the triatomine digestive tract (TDT), the analysis of the TDT protein profile is an essential step to understand TDT physiology during T. cruzi infection. To characterize the protein profile of TDT of D. maxima, P. megistus, R. prolixus, and T. infestans, a shotgun liquid chromatography-tandem mass spectrometry (LC-MS/MS) approach was applied in this report. Most proteins were found to be closely related to metabolic pathways such as gluconeogenesis/glycolysis, citrate cycle, fatty acid metabolism, oxidative phosphorylation, but also to the immune system. We annotated this new proteome contribution gathering it with those previously published in accordance with Gene Ontology and KEGG. Enzymes were classified in terms of class, acceptor, and function, while the proteins from the immune system were annotated by reference to the pathways of humoral response, cell cycle regulation, Toll, IMD, JNK, Jak-STAT, and MAPK, as available from the Insect Innate Immunity Database (IIID). These pathways were further subclassified in recognition, signaling, response, coagulation, melanization and none. Finally, phylogenetic affinities and gene expression of annexins were investigated for understanding their role in the protection and homeostasis of intestinal epithelial cells against the inflammation.
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Affiliation(s)
- Marcia Gumiel
- Laboratório de Bioquímica e Fisiologia de Insetos, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz (IOC/FIOCRUZ), Rio de Janeiro, Brazil
- Research Department, Universidad Privada Franz Tamayo (UNIFRANZ), La Paz, Bolivia
| | - Debora Passos de Mattos
- Laboratório de Biologia de Insetos, Departamento de Biologia Geral, Universidade Federal Fluminense, Niterói, Brazil
- Programa de Pós-Graduação em Ciências e Biotecnologia, Instituto de Biologia, Universidade Federal Fluminense, Niterói, Brazil
| | - Cecília Stahl Vieira
- Laboratório de Bioquímica e Fisiologia de Insetos, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz (IOC/FIOCRUZ), Rio de Janeiro, Brazil
- Departamento de Entomologia Molecular, Instituto Nacional de Entomologia Molecular (INCT-EM), Rio de Janeiro, Brazil
| | - Caroline Silva Moraes
- Laboratório de Bioquímica e Fisiologia de Insetos, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz (IOC/FIOCRUZ), Rio de Janeiro, Brazil
| | | | - Marcelo Salabert Gonzalez
- Laboratório de Biologia de Insetos, Departamento de Biologia Geral, Universidade Federal Fluminense, Niterói, Brazil
- Programa de Pós-Graduação em Ciências e Biotecnologia, Instituto de Biologia, Universidade Federal Fluminense, Niterói, Brazil
- Departamento de Entomologia Molecular, Instituto Nacional de Entomologia Molecular (INCT-EM), Rio de Janeiro, Brazil
| | | | - Mariana Waghabi
- Laboratório de Genômica Funcional e Bioinformática, Instituto Oswaldo Cruz, FIOCRUZ, Rio de Janeiro, Brazil
| | - Patricia Azambuja
- Laboratório de Bioquímica e Fisiologia de Insetos, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz (IOC/FIOCRUZ), Rio de Janeiro, Brazil
- Laboratório de Biologia de Insetos, Departamento de Biologia Geral, Universidade Federal Fluminense, Niterói, Brazil
- Programa de Pós-Graduação em Ciências e Biotecnologia, Instituto de Biologia, Universidade Federal Fluminense, Niterói, Brazil
- Departamento de Entomologia Molecular, Instituto Nacional de Entomologia Molecular (INCT-EM), Rio de Janeiro, Brazil
| | - Nicolas Carels
- Laboratório de Modelagem de Sistemas Biológicos, National Institute for Science and Technology on Innovation in Neglected Diseases (INCT-IDN), Centro de Desenvolvimento Tecnológico em Saúde (CDTS), Fundação Oswaldo Cruz (FIOCRUZ), Rio de Janeiro, Brazil
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21
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González-González A, Wayne ML. Immunopathology and immune homeostasis during viral infection in insects. Adv Virus Res 2020; 107:285-314. [PMID: 32711732 DOI: 10.1016/bs.aivir.2020.06.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Organisms clear infections by mounting an immune response that is normally turned off once the pathogens have been cleared. However, sometimes this immune response is not properly or timely arrested, resulting in the host damaging itself. This immune dysregulation may be referred to as immunopathology. While our knowledge of immune and metabolic pathways in insects, particularly in response to viral infections, is growing, little is known about the mechanisms that regulate this immune response and hence little is known about immunopathology in this important and diverse group of organisms. In this chapter we focus both on documenting the molecular mechanisms described involved in restoring immune homeostasis in insects after viral infections and on identifying potential mechanisms for future investigation. We argue that learning about the immunopathological consequences of an improperly regulated immune response in insects will benefit both insect and human health.
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Affiliation(s)
| | - Marta L Wayne
- Department of Biology, University of Florida, Gainesville, FL, United States
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22
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Animals have a Plan B: how insects deal with the dual challenge of predators and pathogens. J Comp Physiol B 2020; 190:381-390. [PMID: 32529590 DOI: 10.1007/s00360-020-01282-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Revised: 04/08/2020] [Accepted: 04/27/2020] [Indexed: 12/15/2022]
Abstract
When animals are faced with a life-threatening challenge, they mount an organism-wide response (i.e. Plan A). For example, both the stress response (i.e. fight-or-flight) and the immune response recruit molecular resources from other body tissues, and induce physiological changes that optimize the body for defense. However, pathogens and predators often co-occur. Animals that can optimize responses for a dual challenge, i.e. simultaneous predator and pathogen attacks, will have a selective advantage. Responses to a combined predator and pathogen attack have not been well studied, but this paper summarizes the existing literature in insects. The response to dual challenges (i.e. Plan B) results in a suite of physiological changes that are different from either the stress response or the immune response, and is not a simple summation of the two. It is also not a straight-forward trade-off of one response against the other. The response to a dual challenge (i.e. Plan B) appears to resolve physiological trade-offs between the stress and immune responses, and reconfigures both responses to provide the best overall defense. However, the dual response appears to be more costly than either response occurring singly, resulting in greater damage from oxidative stress, reduced growth rate, and increased mortality.
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23
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Jehan C, Chogne M, Rigaud T, Moret Y. Sex-specific patterns of senescence in artificial insect populations varying in sex-ratio to manipulate reproductive effort. BMC Evol Biol 2020; 20:18. [PMID: 32013878 PMCID: PMC6998128 DOI: 10.1186/s12862-020-1586-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2019] [Accepted: 01/24/2020] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND The disposable soma theory of ageing assumes that organisms optimally trade-off limited resources between reproduction and longevity to maximize fitness. Early reproduction should especially trade-off against late reproduction and longevity because of reduced investment into somatic protection, including immunity. Moreover, as optimal reproductive strategies of males and females differ, sexually dimorphic patterns of senescence may evolve. In particular, as males gain fitness through mating success, sexual competition should be a major factor accelerating male senescence. In a single experiment, we examined these possibilities by establishing artificial populations of the mealworm beetle, Tenebrio molitor, in which we manipulated the sex-ratio to generate variable levels of investment into reproductive effort and sexual competition in males and females. RESULTS As predicted, variation in sex-ratio affected male and female reproductive efforts, with contrasted sex-specific trade-offs between lifetime reproduction, survival and immunity. High effort of reproduction accelerated mortality in females, without affecting immunity, but high early reproductive success was observed only in balanced sex-ratio condition. Male reproduction was costly on longevity and immunity, mainly because of their investment into copulations rather than in sexual competition. CONCLUSIONS Our results suggest that T. molitor males, like females, maximize fitness through enhanced longevity, partly explaining their comparable longevity.
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Affiliation(s)
- Charly Jehan
- UMR CNRS 6282 BioGéoSciences, Équipe Écologie Évolutive, Université Bourgogne-Franche Comté, Dijon, France.
| | - Manon Chogne
- UMR CNRS 6282 BioGéoSciences, Équipe Écologie Évolutive, Université Bourgogne-Franche Comté, Dijon, France
| | - Thierry Rigaud
- UMR CNRS 6282 BioGéoSciences, Équipe Écologie Évolutive, Université Bourgogne-Franche Comté, Dijon, France
| | - Yannick Moret
- UMR CNRS 6282 BioGéoSciences, Équipe Écologie Évolutive, Université Bourgogne-Franche Comté, Dijon, France.
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24
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Metcalf CJE, Roth O, Graham AL. Why leveraging sex differences in immune trade-offs may illuminate the evolution of senescence. Funct Ecol 2020; 34:129-140. [PMID: 32063662 PMCID: PMC7006808 DOI: 10.1111/1365-2435.13458] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Accepted: 09/10/2019] [Indexed: 12/15/2022]
Abstract
The immune system affects senescence (declines in probabilities of survival or reproduction with age), by shaping late age vulnerability to chronic inflammatory diseases and infections. It is also a dynamic interactive system that must balance competing demands across the life course. Thus, immune system function remains an important frontier in understanding the evolution of senescence.Here, we review our expanding mechanistic understanding of immune function over the life course, in the context of theoretical predictions from life-history evolution. We are especially interested in stage- and sex-dependent costs and benefits of investment in the immune system, given differential life-history priorities of the life stages and sexes.We introduce the costs likely to govern immune allocation across the life course. We then discuss theoretical expectations for differences between the sexes and their likely consequences in terms of how the immune system is both modulated by and may modulate senescence, building on information from life-history theory, experimental immunology and demography.We argue that sex differences in immune function provide a potentially powerful probe of selection pressures on the immune system across the life course. In particular, differences in 'competing' and 'caring' between the sexes have evolved across the tree of life, providing repeated instances of divergent selection pressures on immune function occurring within the same overall bauplan.We conclude by detailing an agenda for future research, including development of theoretical predictions of the differences between the sexes under an array of existing models for sex differences in immunity, and empirical tests of such predictions across the tree of life. A free http://onlinelibrary.wiley.com/doi/10.1111/1365-2435.13458/suppinfo can be found within the Supporting Information of this article.
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Affiliation(s)
| | - Olivia Roth
- GEOMAR, Marine Evolutionary EcologyHelmholtz Centre for Ocean ResearchKielGermany
| | - Andrea L. Graham
- Department of Ecology and Evolutionary BiologyPrinceton UniversityPrincetonNJUSA
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25
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Babin A, Moreau J, Moret Y. Storage of Carotenoids in Crustaceans as an Adaptation to Modulate Immunopathology and Optimize Immunological and Life-History Strategies. Bioessays 2019; 41:e1800254. [PMID: 31566782 DOI: 10.1002/bies.201800254] [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: 12/11/2018] [Revised: 08/11/2019] [Indexed: 12/14/2022]
Abstract
Why do some invertebrates store so much carotenoids in their tissues? Storage of carotenoids may not simply be passive and dependent on their environmental availability, as storage variation exists at various taxonomic scales, including among individuals within species. While the strong antioxidant and sometimes immune-stimulating properties of carotenoids may be beneficial enough to cause the evolution of features improving their assimilation and storage, they may also have fitness downsides explaining why massive carotenoid storage is not universal. Here, the functional and ecological implications of carotenoid storage for the evolution of invertebrate innate immune defenses are examined, especially in crustaceans, which massively store carotenoids for unclear reasons. Three testable hypotheses about the role of carotenoid storage in immunological (resistance and tolerance) and life-history strategies (with a focus on aging) are proposed, which may ultimately explain the storage of large amounts of these pigments in a context of host-pathogen interactions.
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Affiliation(s)
- Aurélie Babin
- Équipe Écologie Évolutive, UMR CNRS 6282 Biogéosciences, Université Bourgogne Franche-Comté, 6 Boulevard Gabriel, F-21000, Dijon, France
| | - Jérôme Moreau
- Équipe Écologie Évolutive, UMR CNRS 6282 Biogéosciences, Université Bourgogne Franche-Comté, 6 Boulevard Gabriel, F-21000, Dijon, France
| | - Yannick Moret
- Équipe Écologie Évolutive, UMR CNRS 6282 Biogéosciences, Université Bourgogne Franche-Comté, 6 Boulevard Gabriel, F-21000, Dijon, France
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26
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El Shazely B, Urbański A, Johnston PR, Rolff J. In vivo exposure of insect AMP resistant Staphylococcus aureus to an insect immune system. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2019; 110:60-68. [PMID: 31051236 DOI: 10.1016/j.ibmb.2019.04.017] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/01/2019] [Revised: 04/04/2019] [Accepted: 04/29/2019] [Indexed: 06/09/2023]
Abstract
Antimicrobial peptides (AMPs) are important immune effectors in insects. Bacteria have a limited number of ways to resist AMPs, and AMP-resistance is often costly. Recently, it has become clear that AMP activities in vitro and in vivo differ. Although some studies have followed the in vivo survival of AMP resistant pathogens, studying a pathogen resistant to the AMPs of that particular host has never been reported. Here, we infected the mealworm beetle Tenebrio molitor with Staphylococcus aureus strains that were evolved in vitro in the presence of one or two antimicrobial peptides from T. molitor. We found that the Tenebrio immune system could clear mutant Tenecin resistant strains at least as efficiently as sensitive controls. The bacterial load of Tenecin resistant S. aureus segregated by mutation. Strains with mutations in both the pmt and rpo operons showed the highest in vivo survival and therefore showed the lowest fitness cost amongst the evolved resistance mutations. In contrast, Tenecin resistant strains with mutations in the nsa and rpo operons showed much lower survival within the hosts. Our study shows that Tenecin resistant strains are phagocytosed at a lower rate. The nsa/rpo mutants were phagocytosed at a higher rate than other Tenecin resistant S. aureus strains. The differences in resistance against AMPs and phagocytosis did not translate into changes in virulence. AMP resistance, while a prerequisite for an infection in vertebrates, does not provide a survival advantage to S. aureus in a host environment that is dominated by AMPs.
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Affiliation(s)
- Baydaa El Shazely
- Evolutionary Biology, Institute for Biology, Free University of Berlin, Berlin, Germany; Zoology Department, Faculty of Science, Alexandria University, Alexandria, Egypt
| | - Arkadiusz Urbański
- Department of Animal Physiology and Development, Faculty of Biology, Adam Mickiewicz University in Poznań, Poland
| | - Paul R Johnston
- Evolutionary Biology, Institute for Biology, Free University of Berlin, Berlin, Germany; Berlin Center for Genomics in Biodiversity Research, Berlin, Germany; Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB), Berlin, Germany
| | - Jens Rolff
- Evolutionary Biology, Institute for Biology, Free University of Berlin, Berlin, Germany; Berlin Center for Genomics in Biodiversity Research, Berlin, Germany; Berlin-Brandenburg Institute of Advanced Biodiversity Research (BBIB), Berlin, Germany.
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27
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Miyashita A, Lee TYM, McMillan LE, Easy R, Adamo SA. Immunity for nothing and the eggs for free: Apparent lack of both physiological trade-offs and terminal reproductive investment in female crickets (Gryllus texensis). PLoS One 2019; 14:e0209957. [PMID: 31091239 PMCID: PMC6519836 DOI: 10.1371/journal.pone.0209957] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Accepted: 04/30/2019] [Indexed: 12/28/2022] Open
Abstract
Should females alter their reproductive strategy when attacked by pathogens? Two hypotheses provide opposite predictions. Terminal reproductive investment theory predicts that reproduction should increase when the risk of death increases. However, physiological trade-offs between reproduction and immune function might be expected to produce a decrease in reproduction during a robust immune response. There is evidence for both hypotheses. We examine whether age determines the effect of an immune challenge on reproductive strategy in long-winged females of the Texas field cricket, Gryllus texensis, when fed an ecologically valid (i.e. limited) diet. The limited diet reduced reproductive output. However, even under resource-limited conditions, immune challenge had no effect on the reproductive output of young or middle-aged females. Both reproductive output and immune function (lysozyme-like activity and phenoloxidase (PO) activity) increased with age, which is contrary to both hypotheses. We hypothesize that PO activity is pleiotropic and represents an investment in both reproduction and immune function. Three proPO genes (identified in a published RNA-seq dataset (transcriptome)) were expressed either in the fat body or the ovaries (supporting the hypothesis that PO is bifunctional). The possible bifunctionality of PO suggests that it may not be an appropriate immune measure for studies on immune/reproductive trade-offs. This study also suggests that the threshold for terminal reproductive investment may not decrease prior to senescence in some species.
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Affiliation(s)
- Atsushi Miyashita
- Department of Psychology and Neuroscience, Dalhousie University, Halifax, Nova Scotia, Canada
- * E-mail:
| | - Ting Yat Marco Lee
- Department of Psychology and Neuroscience, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Laura E. McMillan
- Department of Psychology and Neuroscience, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Russell Easy
- Department of Biology, Acadia University, Wolfville, Nova Scotia, Canada
| | - Shelley A. Adamo
- Department of Psychology and Neuroscience, Dalhousie University, Halifax, Nova Scotia, Canada
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28
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Kutzer MAM, Kurtz J, Armitage SAO. A multi-faceted approach testing the effects of previous bacterial exposure on resistance and tolerance. J Anim Ecol 2019; 88:566-578. [PMID: 30697699 PMCID: PMC6487967 DOI: 10.1111/1365-2656.12953] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2018] [Accepted: 12/03/2018] [Indexed: 01/03/2023]
Abstract
Hosts can alter their strategy towards pathogens during their lifetime; that is, they can show phenotypic plasticity in immunity or life history. Immune priming is one such example, where a previous encounter with a pathogen confers enhanced protection upon secondary challenge, resulting in reduced pathogen load (i.e., resistance) and improved host survival. However, an initial encounter might also enhance tolerance, particularly to less virulent opportunistic pathogens that establish persistent infections. In this scenario, individuals are better able to reduce the negative fecundity consequences that result from a high pathogen burden. Finally, previous exposure may also lead to life‐history adjustments, such as terminal investment into reproduction. Using different Drosophila melanogaster host genotypes and two bacterial pathogens, Lactococcus lactis and Pseudomonas entomophila, we tested whether previous exposure results in resistance or tolerance and whether it modifies immune gene expression during an acute‐phase infection (one day post‐challenge). We then asked whether previous pathogen exposure affects chronic‐phase pathogen persistence and longer‐term survival (28 days post‐challenge). We predicted that previous exposure would increase host resistance to an early stage bacterial infection while it might come at a cost to host fecundity tolerance. We reasoned that resistance would be due in part to stronger immune gene expression after challenge. We expected that previous exposure would improve long‐term survival, that it would reduce infection persistence, and we expected to find genetic variation in these responses. We found that previous exposure to P. entomophila weakened host resistance to a second infection independent of genotype and had no effect on immune gene expression. Fecundity tolerance showed genotypic variation but was not influenced by previous exposure. However, L. lactis persisted as a chronic infection, whereas survivors cleared the more pathogenic P. entomophila infection. To our knowledge, this is the first study that addresses host tolerance to bacteria in relation to previous exposure, taking a multi‐faceted approach to address the topic. Our results suggest that previous exposure comes with transient costs to resistance during the early stage of infection in this host–pathogen system and that infection persistence may be bacterium‐specific.
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Affiliation(s)
- Megan A M Kutzer
- Institute for Evolution and Biodiversity, University of Münster, Münster, Germany.,IST Austria, Klosterneuburg, Austria
| | - Joachim Kurtz
- Institute for Evolution and Biodiversity, University of Münster, Münster, Germany
| | - Sophie A O Armitage
- Institute for Evolution and Biodiversity, University of Münster, Münster, Germany.,Institute of Biology, Freie Universität Berlin, Berlin, Germany
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29
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Lippens C, Guivier E, Reece SE, O’Donnell AJ, Cornet S, Faivre B, Sorci G. Early Plasmodium-induced inflammation does not accelerate aging in mice. Evol Appl 2019; 12:314-323. [PMID: 30697342 PMCID: PMC6346666 DOI: 10.1111/eva.12718] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Revised: 08/30/2018] [Accepted: 09/16/2018] [Indexed: 12/25/2022] Open
Abstract
Aging is associated with a decline of performance leading to reduced reproductive output and survival. While the antagonistic pleiotropy theory of aging has attracted considerable attention, the molecular/physiological functions underlying the early-life benefits/late-life costs paradigm remain elusive. We tested the hypothesis that while early activation of the inflammatory response confers benefits in terms of protection against infection, it also incurs costs in terms of reduced reproductive output at old age and shortened longevity. We infected mice with the malaria parasite Plasmodium yoelii and increased the inflammatory response using an anti-IL-10 receptor antibody treatment. We quantified the benefits and costs of the inflammatory response during the acute phase of the infection and at old age. In agreement with the antagonistic pleiotropy hypothesis, the inflammatory response provided an early-life benefit, since infected mice that were treated with anti-IL-10 receptor antibodies had reduced parasite density and anemia. However, at old age, mice in all treatment groups had similar levels of C-reactive protein, reproductive output, survival rate, and lifespan. Overall, our results do not support the hypothesis that the benefits of a robust response to malaria infection in early life incur longer term fitness costs.
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Affiliation(s)
- Cédric Lippens
- Biogéosciences, CNRS UMR 6282Université de Bourgogne Franche‐ComtéDijonFrance
| | - Emmanuel Guivier
- Biogéosciences, CNRS UMR 6282Université de Bourgogne Franche‐ComtéDijonFrance
- Laboratoire IMBEUniversité Aix MarseilleMarseilleFrance
| | - Sarah E. Reece
- Institutes of Evolutionary Biology, and Immunology and Infection ResearchUniversity of EdinburghEdinburghUK
| | - Aidan J. O’Donnell
- Institutes of Evolutionary Biology, and Immunology and Infection ResearchUniversity of EdinburghEdinburghUK
| | - Stéphane Cornet
- IRDUMR CBGP INRA IRD Cirad Montpellier SupAgroMontpellierFrance
| | - Bruno Faivre
- Biogéosciences, CNRS UMR 6282Université de Bourgogne Franche‐ComtéDijonFrance
| | - Gabriele Sorci
- Biogéosciences, CNRS UMR 6282Université de Bourgogne Franche‐ComtéDijonFrance
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30
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Fabian DK, Garschall K, Klepsatel P, Santos‐Matos G, Sucena É, Kapun M, Lemaitre B, Schlötterer C, Arking R, Flatt T. Evolution of longevity improves immunity in Drosophila. Evol Lett 2018; 2:567-579. [PMID: 30564440 PMCID: PMC6292704 DOI: 10.1002/evl3.89] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2018] [Accepted: 10/24/2018] [Indexed: 12/20/2022] Open
Abstract
Much has been learned about the genetics of aging from studies in model organisms, but still little is known about naturally occurring alleles that contribute to variation in longevity. For example, analysis of mutants and transgenes has identified insulin signaling as a major regulator of longevity, yet whether standing variation in this pathway underlies microevolutionary changes in lifespan and correlated fitness traits remains largely unclear. Here, we have analyzed the genomes of a set of Drosophila melanogaster lines that have been maintained under direct selection for postponed reproduction and indirect selection for longevity, relative to unselected control lines, for over 35 years. We identified many candidate loci shaped by selection for longevity and late-life fertility, but - contrary to expectation - we did not find overrepresentation of canonical longevity genes. Instead, we found an enrichment of immunity genes, particularly in the Toll pathway, suggesting that evolutionary changes in immune function might underpin - in part - the evolution of late-life fertility and longevity. To test whether this genomic signature is causative, we performed functional experiments. In contrast to control flies, long-lived flies tended to downregulate the expression of antimicrobial peptides upon infection with age yet survived fungal, bacterial, and viral infections significantly better, consistent with alleviated immunosenescence. To examine whether genes of the Toll pathway directly affect longevity, we employed conditional knockdown using in vivo RNAi. In adults, RNAi against the Toll receptor extended lifespan, whereas silencing the pathway antagonist cactus--causing immune hyperactivation - dramatically shortened lifespan. Together, our results suggest that genetic changes in the age-dependent regulation of immune homeostasis might contribute to the evolution of longer life.
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Affiliation(s)
- Daniel K. Fabian
- Centre for Pathogen Evolution, Department of ZoologyUniversity of CambridgeCambridgeUnited Kingdom
- Institut für PopulationsgenetikVetmeduni ViennaViennaAustria
- Vienna Graduate School of Population GeneticsViennaAustria
| | - Kathrin Garschall
- Department of Ecology and EvolutionUniversity of LausanneLausanneSwitzerland
| | - Peter Klepsatel
- Institut für PopulationsgenetikVetmeduni ViennaViennaAustria
- Institute of ZoologySlovak Academy of Sciences845 06 BratislavaSlovakia
| | | | - Élio Sucena
- Instituto Gulbenkian de CiênciaOeirasPortugal
- Departamento de Biologia AnimalFaculdade de Ciências da Universidade de LisboaLisboaPortugal
| | - Martin Kapun
- Department of Ecology and EvolutionUniversity of LausanneLausanneSwitzerland
| | - Bruno Lemaitre
- Global Health InstituteSchool of Life Sciences, EPFLLausanneSwitzerland
| | | | - Robert Arking
- Department of Biological SciencesWayne State UniversityDetroitMichigan
| | - Thomas Flatt
- Institut für PopulationsgenetikVetmeduni ViennaViennaAustria
- Department of Ecology and EvolutionUniversity of LausanneLausanneSwitzerland
- Department of BiologyUniversity of FribourgFribourgSwitzerland
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31
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Moore MP, Lis C, Martin RA. Immune deployment increases larval vulnerability to predators and inhibits adult life-history traits in a dragonfly. J Evol Biol 2018; 31:1365-1376. [PMID: 29927003 DOI: 10.1111/jeb.13337] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2018] [Revised: 06/05/2018] [Accepted: 06/19/2018] [Indexed: 01/09/2023]
Abstract
While deploying immune defences early in ontogeny can trade-off with the production and maintenance of other important traits across the entire life cycle, it remains largely unexplored how features of the environment shape the magnitude or presence of these lifetime costs. Greater predation risk during the juvenile stage may particularly influence such costs by (1) magnifying the survival costs that arise from any handicap of juvenile avoidance traits and/or (2) intensifying allocation trade-offs with important adult traits. Here, we tested for predator-dependent costs of immune deployment within and across life stages using the dragonfly, Pachydiplax longipennis. We first examined how larval immune deployment affected two traits associated with larval vulnerability to predators: escape distance and foraging under predation risk. Larvae that were induced to mount an immune response had shorter escape distances but lower foraging activity in the presence of predator cues. We also induced immune responses in larvae and reared them through emergence in mesocosms that differed in the presence of large predatory dragonfly larvae (Aeshnidae spp.). Immune-challenged larvae had later emergence overall and lower survival in pools with predators. Immune-challenged males were also smaller at emergence and developed less sexually selected melanin wing coloration, but these effects were independent of predator treatment. Overall, these results highlight how mounting an immune defence early in ontogeny can have substantial ecological and physiological costs that manifest both within and across life stages.
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Affiliation(s)
- Michael P Moore
- Department of Biology, Case Western Reserve University, Cleveland, OH, USA
| | | | - Ryan A Martin
- Department of Biology, Case Western Reserve University, Cleveland, OH, USA
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32
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Khan I, Prakash A, Agashe D. Experimental evolution of insect immune memory versus pathogen resistance. Proc Biol Sci 2018; 284:rspb.2017.1583. [PMID: 29237849 DOI: 10.1098/rspb.2017.1583] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2017] [Accepted: 11/13/2017] [Indexed: 12/13/2022] Open
Abstract
Under strong pathogen pressure, insects often evolve resistance to infection. Many insects are also protected via immune memory (immune priming), whereby sublethal exposure to a pathogen enhances survival after secondary infection. Theory predicts that immune memory should evolve when the pathogen is highly virulent, or when pathogen exposure is relatively rare. However, there are no empirical tests of these hypotheses, and the adaptive benefits of immune memory relative to direct resistance against a pathogen are poorly understood. To determine the selective pressures and ecological conditions that shape immune evolution, we imposed strong pathogen selection on flour beetle (Tribolium castaneum) populations, infecting them with Bacillus thuringiensis (Bt) for 11 generations. Populations injected first with heat-killed and then live Bt evolved high basal resistance against multiple Bt strains. By contrast, populations injected only with a high dose of live Bt evolved a less effective but strain-specific priming response. Control populations injected with heat-killed Bt did not evolve priming; and in the ancestor, priming was effective only against a low Bt dose. Intriguingly, one replicate population first evolved priming and subsequently evolved basal resistance, suggesting the potential for dynamic evolution of different immune strategies. Our work is the first report showing that pathogens can select for rapid modulation of insect priming ability, allowing hosts to evolve divergent immune strategies (generalized resistance versus specific immune memory) with potentially distinct mechanisms.
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Affiliation(s)
- Imroze Khan
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, GKVK, Bellary Road, Bangalore 560065, India .,Ashoka University, Plot No. 2, Rajiv Gandhi Education City, National Capital Region, P.O. Rai, Sonepat, Haryana 131029, India
| | - Arun Prakash
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, GKVK, Bellary Road, Bangalore 560065, India
| | - Deepa Agashe
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, GKVK, Bellary Road, Bangalore 560065, India
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33
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Duffield KR, Hampton KJ, Houslay TM, Hunt J, Rapkin J, Sakaluk SK, Sadd BM. Age‐dependent variation in the terminal investment threshold in male crickets. Evolution 2018; 72:578-589. [DOI: 10.1111/evo.13443] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2017] [Revised: 01/26/2018] [Accepted: 01/29/2018] [Indexed: 01/17/2023]
Affiliation(s)
- Kristin R. Duffield
- Behavior, Ecology, Evolution and Systematics Section, School of Biological Sciences Illinois State University Normal Illinois 61761
| | - Kylie J. Hampton
- Behavior, Ecology, Evolution and Systematics Section, School of Biological Sciences Illinois State University Normal Illinois 61761
| | - Thomas M. Houslay
- Center for Ecology and Conservation, College of Life and Environmental Sciences University of Exeter Penryn TR10 9FE United Kingdom
| | - John Hunt
- Center for Ecology and Conservation, College of Life and Environmental Sciences University of Exeter Penryn TR10 9FE United Kingdom
- School of Science and Health and Hawkesbury Institute for the Environment, Western Sydney University Penrith NSW 2751 Australia
| | - James Rapkin
- Center for Ecology and Conservation, College of Life and Environmental Sciences University of Exeter Penryn TR10 9FE United Kingdom
| | - Scott K. Sakaluk
- Behavior, Ecology, Evolution and Systematics Section, School of Biological Sciences Illinois State University Normal Illinois 61761
| | - Ben M. Sadd
- Behavior, Ecology, Evolution and Systematics Section, School of Biological Sciences Illinois State University Normal Illinois 61761
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34
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Abstract
Here, we provide a brief review of the mechanistic connections between immunity and aging—a fundamental biological relationship that remains poorly understood—by considering two intertwined questions: how does aging affect immunity, and how does immunity affect aging? On the one hand, aging contributes to the deterioration of immune function and predisposes the organism to infections (“immuno-senescence”). On the other hand, excessive activation of the immune system can accelerate degenerative processes, cause inflammation and immunopathology, and thus promote aging (“inflammaging”). Interestingly, several recent lines of evidence support the hypothesis that restrained or curbed immune activity at old age (that is, optimized age-dependent immune homeostasis) might actually improve realized immune function and thereby promote longevity. We focus mainly on insights from
Drosophila, a powerful genetic model system in which both immunity and aging have been extensively studied, and conclude by outlining several unresolved questions in the field.
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Affiliation(s)
- Kathrin Garschall
- Department of Ecology & Evolution, University of Lausanne, Lausanne, Switzerland
| | - Thomas Flatt
- Department of Ecology & Evolution, University of Lausanne, Lausanne, Switzerland.,Department of Biology, University of Fribourg, Fribourg, Switzerland
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35
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Vogelweith F, Foitzik S, Meunier J. Age, sex, mating status, but not social isolation interact to shape basal immunity in a group-living insect. JOURNAL OF INSECT PHYSIOLOGY 2017; 103:64-70. [PMID: 29038016 DOI: 10.1016/j.jinsphys.2017.10.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2017] [Revised: 09/10/2017] [Accepted: 10/12/2017] [Indexed: 06/07/2023]
Abstract
Immunity is a crucial but costly trait. Individuals should therefore adjust their investment into immunity to their condition and infection risks, which are often determined by their age, sex, mating status and social environment. However, whether and how these four key factors can interact to shape basal immunity remains poorly understood. Here, we tested the simultaneous effects of these factors on hemocyte concentration and phenoloxidase activity in adults of the European earwig. We found that hemocyte concentration increased with age, and that this increase was stronger in males. We also found an age-dependent increase in phenoloxidase activity in males and virgin females, but not in mated females. However, the two immune parameters were independent of social isolation. Overall, our results reveal that a complex interplay between age, sex and mating status determines basal immunity and stress the importance of interactions in our understanding of immune investment.
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Affiliation(s)
- Fanny Vogelweith
- Institute of Organismic and Molecular Evolution, Behavioral Ecology and Social Evolution Group, Johannes-Gutenberg University of Mainz, Mainz, Germany.
| | - Susanne Foitzik
- Institute of Organismic and Molecular Evolution, Behavioral Ecology and Social Evolution Group, Johannes-Gutenberg University of Mainz, Mainz, Germany
| | - Joël Meunier
- Institute of Organismic and Molecular Evolution, Behavioral Ecology and Social Evolution Group, Johannes-Gutenberg University of Mainz, Mainz, Germany; Institut de Recherche sur la Biologie de l'Insecte, UMR CNRS 7261, University of Tours, Tours, France
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36
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Dhinaut J, Balourdet A, Teixeira M, Chogne M, Moret Y. A dietary carotenoid reduces immunopathology and enhances longevity through an immune depressive effect in an insect model. Sci Rep 2017; 7:12429. [PMID: 28963510 PMCID: PMC5622072 DOI: 10.1038/s41598-017-12769-7] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2017] [Accepted: 09/15/2017] [Indexed: 11/09/2022] Open
Abstract
Immunopathology corresponds to self-damage of the inflammatory response, resulting from oxidizing molecules produced when the immune system is activated. Immunopathology often contributes to age-related diseases and is believed to accelerate ageing. Prevention of immunopathology relies on endogenous antioxidant enzymes and the consumption of dietary antioxidants, including carotenoids such as astaxanthin. Astaxanthin currently raises considerable interest as a powerful antioxidant and for its potential in alleviating age-related diseases. Current in vitro and short-term in vivo studies provide promising results about immune-stimulating and antioxidant properties of astaxanthin. However, to what extent dietary supplementation with astaxanthin can prevent long-term adverse effects of immunopathology on longevity is unknown so far. Here, using the mealworm beetle, Tenebrio molitor, as biological model we tested the effect of lifetime dietary supplementation with astaxanthin on longevity when exposed to early life inflammation. While supplementation with astaxanthin was found to lessen immunopathology cost on larval survival and insect longevity, it was also found to reduce immunity, growth rate and the survival of non immune-challenged larvae. This study therefore reveals that astaxanthin prevents immunopathology through an immune depressive effect and can have adverse consequences on growth.
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Affiliation(s)
- Julien Dhinaut
- UMR CNRS 6282 BioGéoSciences, Équipe Écologie Évolutive, Université Bourgogne-Franche Comté, Dijon, France
| | - Aude Balourdet
- UMR CNRS 6282 BioGéoSciences, Équipe Écologie Évolutive, Université Bourgogne-Franche Comté, Dijon, France
| | - Maria Teixeira
- UMR CNRS 6282 BioGéoSciences, Équipe Écologie Évolutive, Université Bourgogne-Franche Comté, Dijon, France
| | - Manon Chogne
- UMR CNRS 6282 BioGéoSciences, Équipe Écologie Évolutive, Université Bourgogne-Franche Comté, Dijon, France
| | - Yannick Moret
- UMR CNRS 6282 BioGéoSciences, Équipe Écologie Évolutive, Université Bourgogne-Franche Comté, Dijon, France.
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Demographically framing trade-offs between sensitivity and specificity illuminates selection on immunity. Nat Ecol Evol 2017; 1:1766-1772. [PMID: 28963489 DOI: 10.1038/s41559-017-0315-3] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2017] [Accepted: 07/26/2017] [Indexed: 12/14/2022]
Abstract
A fundamental challenge faced by the immune system is to discriminate contexts meriting activation from contexts in which activation would be harmful. Selection pressures on this ability are likely to be acute: the penalty of mis-identification of pathogens (therefore failure to attack them) is mortality or morbidity linked to infectious disease, which could reduce fitness by reducing lifespan or fertility; the penalty associated with mis-identification of host (therefore self-attack) is immunopathology, whose fitness costs can also be extreme. Here we use classic epidemiological tools to frame this trade-off between sensitivity and specificity of immune activation, exploring implications for evolution of immune discrimination. We capture the expected increase in the evolutionarily optimal sensitivity under higher pathogen mortality risk, and a decrease in sensitivity with increased immunopathology mortality risk; but a number of non-intuitive predictions also emerge. All else being equal, optimal sensitivity decreases with increasing lifespan; and, where sensitivity can vary over age, decreases at late ages not solely attributable to immunosenescence are predicted. These results both enrich and challenge previous predictions concerning the relationship between life expectancy and optimal evolved defenses, highlighting the need to account for epidemiological setting, lifestage-specific immune priorities, and immune discrimination in future investigations.
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