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Sukkar D, Kanso A, Laval-Gilly P, Falla-Angel J. A clash on the Toll pathway: competitive action between pesticides and zymosan A on components of innate immunity in Apis mellifera. Front Immunol 2023; 14:1247582. [PMID: 37753094 PMCID: PMC10518393 DOI: 10.3389/fimmu.2023.1247582] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2023] [Accepted: 08/21/2023] [Indexed: 09/28/2023] Open
Abstract
Background The immune system of honeybees includes multiple pathways that may be affected by pesticide exposure decreasing the immune competencies of bees and increasing their susceptibility to diseases like the fungal Nosema spp. infection, which is detected in collapsed colonies. Methods To better understand the effect of the co-presence of multiple pesticides that interact with bees like imidacloprid and amitraz, we evaluated the expression of immune-related genes in honeybee hemocytes. Results Imidacloprid, amitraz, and the immune activator, zymosan A, mainly affect the gene expression in the Toll pathway. Discussion Imidacloprid, amitraz, and zymosan A have a synergistic or an antagonistic relationship on gene expression depending on the level of immune signaling. The presence of multiple risk factors like pesticides and pathogens requires the assessment of their complex interaction, which has differential effects on the innate immunity of honeybees as seen in this study.
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Affiliation(s)
- Dani Sukkar
- Université de Lorraine, INRAE, LSE, F-54000 Nancy, France
- Biology Department, Faculty of Sciences I, Lebanese University, Hadath, Lebanon
| | - Ali Kanso
- Biology Department, Faculty of Sciences I, Lebanese University, Hadath, Lebanon
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2
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Raval D, Daley L, Eleftherianos I. Drosophila melanogaster larvae are tolerant to oral infection with the bacterial pathogen Photorhabdus luminescens. MICROPUBLICATION BIOLOGY 2023; 2023:10.17912/micropub.biology.000938. [PMID: 37711508 PMCID: PMC10498274 DOI: 10.17912/micropub.biology.000938] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Figures] [Subscribe] [Scholar Register] [Received: 07/29/2023] [Revised: 08/10/2023] [Accepted: 08/28/2023] [Indexed: 09/16/2023]
Abstract
The fruit fly Drosophila melanogaster is an excellent model for dissecting the molecular and functional bases of bacterial pathogenicity and host antibacterial immune response. The Gram-negative bacterium Photorhabdus luminescens is an insect-specific pathogen that forms a mutualistic relationship with the entomopathogenic nematode Heterorhabditis bacteriophora . Here we find that oral infection of D. melanogaster larvae with P. luminescens moderately reduces their survival ability while the bacteria replicate efficiently in the infected insects. This information will contribute towards understanding host gut immunity against potent bacterial pathogens.
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Affiliation(s)
- Dhaivat Raval
- Department of Biological Sciences, The George Washington University, Washington, DC, USA
| | - Lillia Daley
- Department of Biological Sciences, The George Washington University, Washington, DC, USA
| | - Ioannis Eleftherianos
- Department of Biological Sciences, The George Washington University, Washington, DC, USA
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3
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Arch M, Vidal M, Koiffman R, Melkie ST, Cardona PJ. Drosophila melanogaster as a model to study innate immune memory. Front Microbiol 2022; 13:991678. [PMID: 36338030 PMCID: PMC9630750 DOI: 10.3389/fmicb.2022.991678] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Accepted: 10/03/2022] [Indexed: 09/12/2023] Open
Abstract
Over the last decades, research regarding innate immune responses has gained increasing importance. A growing body of evidence supports the notion that the innate arm of the immune system could show memory traits. Such traits are thought to be conserved throughout evolution and provide a survival advantage. Several models are available to study these mechanisms. Among them, we find the fruit fly, Drosophila melanogaster. This non-mammalian model has been widely used for innate immune research since it naturally lacks an adaptive response. Here, we aim to review the latest advances in the study of the memory mechanisms of the innate immune response using this animal model.
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Affiliation(s)
- Marta Arch
- Tuberculosis Research Unit, Germans Trias i Pujol Research Institute (IGTP), Badalona, Spain
- Department of Genetics and Microbiology, Universitat Autònoma de Barcelona, Bellaterra, Spain
| | - Maria Vidal
- Tuberculosis Research Unit, Germans Trias i Pujol Research Institute (IGTP), Badalona, Spain
- Department of Genetics and Microbiology, Universitat Autònoma de Barcelona, Bellaterra, Spain
- Comparative Medicine and Bioimage Centre of Catalonia (CMCiB), Germans Trias I Pujol Research Institute (IGTP), Badalona, Spain
- Microbiology Department, Laboratori Clínic Metropolitana Nord, Germans Trias i Pujol University Hospital, Badalona, Spain
| | - Romina Koiffman
- Tuberculosis Research Unit, Germans Trias i Pujol Research Institute (IGTP), Badalona, Spain
- UCBL, UnivLyon, Université Claude Bernard Lyon 1 (UCBL1), Villeurbanne, France
| | - Solomon Tibebu Melkie
- Tuberculosis Research Unit, Germans Trias i Pujol Research Institute (IGTP), Badalona, Spain
- UCBL, UnivLyon, Université Claude Bernard Lyon 1 (UCBL1), Villeurbanne, France
| | - Pere-Joan Cardona
- Tuberculosis Research Unit, Germans Trias i Pujol Research Institute (IGTP), Badalona, Spain
- Department of Genetics and Microbiology, Universitat Autònoma de Barcelona, Bellaterra, Spain
- Comparative Medicine and Bioimage Centre of Catalonia (CMCiB), Germans Trias I Pujol Research Institute (IGTP), Badalona, Spain
- Microbiology Department, Laboratori Clínic Metropolitana Nord, Germans Trias i Pujol University Hospital, Badalona, Spain
- Centro de Investigación Biomédica en Red en Enfermedades Respiratorias (CIBERES), Instituto de Salud Carlos III (ISCIII), Madrid, Spain
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4
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Parks SC, Nguyen S, Nasrolahi S, Bhat C, Juncaj D, Lu D, Ramaswamy R, Dhillon H, Fujiwara H, Buchman A, Akbari OS, Yamanaka N, Boulanger MJ, Dillman AR. Parasitic nematode fatty acid- and retinol-binding proteins compromise host immunity by interfering with host lipid signaling pathways. PLoS Pathog 2021; 17:e1010027. [PMID: 34714893 PMCID: PMC8580252 DOI: 10.1371/journal.ppat.1010027] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Revised: 11/10/2021] [Accepted: 10/11/2021] [Indexed: 12/19/2022] Open
Abstract
Parasitic nematodes cause significant morbidity and mortality globally. Excretory/secretory products (ESPs) such as fatty acid- and retinol- binding proteins (FARs) are hypothesized to suppress host immunity during nematode infection, yet little is known about their interactions with host tissues. Leveraging the insect parasitic nematode, Steinernema carpocapsae, we describe here the first in vivo study demonstrating that FARs modulate animal immunity, causing an increase in susceptibility to bacterial co-infection. Moreover, we show that FARs dampen key components of the fly immune response including the phenoloxidase cascade and antimicrobial peptide (AMP) production. Our data also reveal that FARs deplete lipid signaling precursors in vivo as well as bind to these fatty acids in vitro, suggesting that FARs elicit their immunomodulatory effects by altering the availability of lipid signaling molecules necessary for an efficient immune response. Collectively, these data support a complex role for FARs in immunosuppression in animals and provide detailed mechanistic insight into parasitism in phylum Nematoda.
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Affiliation(s)
- Sophia C. Parks
- Department of Nematology, University of California, Riverside, California, United States of America
| | - Susan Nguyen
- Department of Nematology, University of California, Riverside, California, United States of America
| | - Shyon Nasrolahi
- Department of Nematology, University of California, Riverside, California, United States of America
| | - Chaitra Bhat
- Department of Nematology, University of California, Riverside, California, United States of America
| | - Damian Juncaj
- Department of Nematology, University of California, Riverside, California, United States of America
| | - Dihong Lu
- Department of Nematology, University of California, Riverside, California, United States of America
| | - Raghavendran Ramaswamy
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, British Columbia, Canada
| | - Harpal Dhillon
- Department of Nematology, University of California, Riverside, California, United States of America
| | - Hideji Fujiwara
- Division of Endocrinology, Metabolism, and Lipid Research, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Anna Buchman
- Division of Biological Sciences, Section of Cell and Developmental Biology, University of California, San Diego, California, United States of America
| | - Omar S. Akbari
- Division of Biological Sciences, Section of Cell and Developmental Biology, University of California, San Diego, California, United States of America
| | - Naoki Yamanaka
- Department of Entomology, University of California, Riverside, California, United States of America
| | - Martin J. Boulanger
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, British Columbia, Canada
| | - Adler R. Dillman
- Department of Nematology, University of California, Riverside, California, United States of America
- * E-mail:
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5
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Groisman EA, Duprey A, Choi J. How the PhoP/PhoQ System Controls Virulence and Mg 2+ Homeostasis: Lessons in Signal Transduction, Pathogenesis, Physiology, and Evolution. Microbiol Mol Biol Rev 2021; 85:e0017620. [PMID: 34191587 PMCID: PMC8483708 DOI: 10.1128/mmbr.00176-20] [Citation(s) in RCA: 48] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
The PhoP/PhoQ two-component system governs virulence, Mg2+ homeostasis, and resistance to a variety of antimicrobial agents, including acidic pH and cationic antimicrobial peptides, in several Gram-negative bacterial species. Best understood in Salmonella enterica serovar Typhimurium, the PhoP/PhoQ system consists o-regulated gene products alter PhoP-P amounts, even under constant inducing conditions. PhoP-P controls the abundance of hundreds of proteins both directly, by having transcriptional effects on the corresponding genes, and indirectly, by modifying the abundance, activity, or stability of other transcription factors, regulatory RNAs, protease regulators, and metabolites. The investigation of PhoP/PhoQ has uncovered novel forms of signal transduction and the physiological consequences of regulon evolution.
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Affiliation(s)
- Eduardo A. Groisman
- Department of Microbial Pathogenesis, Yale School of Medicine, New Haven, Connecticut, USA
- Yale Microbial Sciences Institute, West Haven, Connecticut, USA
| | - Alexandre Duprey
- Department of Microbial Pathogenesis, Yale School of Medicine, New Haven, Connecticut, USA
| | - Jeongjoon Choi
- Department of Microbial Pathogenesis, Yale School of Medicine, New Haven, Connecticut, USA
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6
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Faucher C, Mazana V, Kardacz M, Parthuisot N, Ferdy JB, Duneau D. Step-Specific Adaptation and Trade-Off over the Course of an Infection by GASP Mutation Small Colony Variants. mBio 2021; 12:e01399-20. [PMID: 33436427 PMCID: PMC7845629 DOI: 10.1128/mbio.01399-20] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Accepted: 11/17/2020] [Indexed: 11/20/2022] Open
Abstract
During an infection, parasites face a succession of challenges, each decisive for disease outcome. The diversity of challenges requires a series of parasite adaptations to successfully multiply and transmit from host to host. Thus, the pathogen genotypes that succeed during one step might be counterselected in later stages of the infection. Using the bacterium Xenorhabdus nematophila and adult Drosophila melanogaster flies as hosts, we showed that such step-specific adaptations, here linked to GASP (i.e., growth advantage in stationary phase) mutations in the X. nematophila master gene regulator lrp, exist and can trade off with each other. We found that nonsense lrp mutations had lowered the ability to resist the host immune response, while all classes of mutations in lrp were associated with a decrease in the ability to proliferate during early infection. We demonstrate that reduced proliferation of X. nematophila best explains diminished virulence in this infection model. Finally, decreased proliferation during the first step of infection is accompanied by improved proliferation during late infection, suggesting a trade-off between the adaptations to each step. Step-specific adaptations could play a crucial role in the chronic phase of infections in any disease organisms that show similar small colony variants (SCVs) to X. nematophilaIMPORTANCE Within-host evolution has been described in many bacterial diseases, and the genetic basis behind the adaptations has stimulated a lot of interest. Yet, the studied adaptations are generally focused on antibiotic resistance and rarely on the adaptation to the environment given by the host, and the potential trade-offs hindering adaptations to each step of the infection are rarely considered. Those trade-offs are key to understanding intrahost evolution and thus the dynamics of the infection. However, understanding these trade-offs supposes a detailed study of host-pathogen interactions at each step of the infection process, with an adapted methodology for each step. Using Drosophila melanogaster as the host and the bacterium Xenorhabdus nematophila, we investigated the bacterial adaptations resulting from GASP mutations known to induce the small colony variant (SCV) phenotype positively selected within the host over the course of an infection, as well as the trade-off between step-specific adaptations.
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Affiliation(s)
- Christian Faucher
- CNRS, UMR5174 EDB (Laboratoire Évolution & Diversité Biologique), Université Toulouse 3 Paul Sabatier, Toulouse, France
| | - Vincent Mazana
- CNRS, UMR5174 EDB (Laboratoire Évolution & Diversité Biologique), Université Toulouse 3 Paul Sabatier, Toulouse, France
| | - Marion Kardacz
- CNRS, UMR5174 EDB (Laboratoire Évolution & Diversité Biologique), Université Toulouse 3 Paul Sabatier, Toulouse, France
| | - Nathalie Parthuisot
- CNRS, UMR5174 EDB (Laboratoire Évolution & Diversité Biologique), Université Toulouse 3 Paul Sabatier, Toulouse, France
| | - Jean-Baptiste Ferdy
- CNRS, UMR5174 EDB (Laboratoire Évolution & Diversité Biologique), Université Toulouse 3 Paul Sabatier, Toulouse, France
| | - David Duneau
- CNRS, UMR5174 EDB (Laboratoire Évolution & Diversité Biologique), Université Toulouse 3 Paul Sabatier, Toulouse, France
- Instituto Gulbenkian de Ciência, Oeiras, Portugal
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7
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Ozakman Y, Eleftherianos I. Immune interactions between Drosophila and the pathogen Xenorhabdus. Microbiol Res 2020; 240:126568. [PMID: 32781380 DOI: 10.1016/j.micres.2020.126568] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Revised: 07/24/2020] [Accepted: 07/25/2020] [Indexed: 12/22/2022]
Abstract
Deciphering host innate immune function and bacterial pathogenic tactics require a system that facilitates both facets of host-pathogen interactions. In recent years, a model that becomes established in dissecting mechanisms of host antibacterial immune response through probing with a potent bacterial pathogen involves the fruit fly Drosophila melanogaster and the insect pathogenic bacteria Xenorhabdus spp. The elegance of this system involves not only the genetic tractability of D. melanogaster, but also the association of Xenorhabdus with parasitic nematodes of insects that supervise the release of the bacteria as well as influence their pathogenic properties during the infection process. These dynamic aspects have enabled us to start decoding the specific features of the D. melanogaster host defense that participate in confronting the activity of Xenorhabdus molecular components, which are designed to evade the immune system. Here we outline recent information on the cellular, humoral and phenoloxidase reactions that are induced in D. melanogaster larvae and adults to oppose the Xenorhabdus attack, and the bacterial factors responsible for triggering these effects. This knowledge is critical not only for understanding how invertebrate immunity operates, but also for devising novel approaches to exploit the virulence ability of certain bacteria with the ultimate goal to counteract harmful insect pests or vectors of infectious disease.
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Affiliation(s)
- Yaprak Ozakman
- Infection and Innate Immunity Lab, Department of Biological Sciences, Institute for Biomedical Sciences, The George Washington University, Science and Engineering Hall, 800 22nd Street NW, Washington DC 20052, USA
| | - Ioannis Eleftherianos
- Infection and Innate Immunity Lab, Department of Biological Sciences, Institute for Biomedical Sciences, The George Washington University, Science and Engineering Hall, 800 22nd Street NW, Washington DC 20052, USA.
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8
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Huot L, Bigourdan A, Pagès S, Ogier JC, Girard PA, Nègre N, Duvic B. Partner-specific induction of Spodoptera frugiperda immune genes in response to the entomopathogenic nematobacterial complex Steinernema carpocapsae-Xenorhabdus nematophila. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2020; 108:103676. [PMID: 32184079 DOI: 10.1016/j.dci.2020.103676] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Revised: 03/10/2020] [Accepted: 03/11/2020] [Indexed: 06/10/2023]
Abstract
The Steinernema carpocapsae-Xenorhabdus nematophila association is a nematobacterial complex used in biological control of insect crop pests. The infection success of this dual pathogen strongly depends on its interactions with the host's immune system. Here, we used the lepidopteran pest Spodoptera frugiperda to analyze the respective impact of each partner in the induction of its immune responses. First, we used previously obtained RNAseq data to construct the immunome of S. frugiperda and analyze its induction. We then selected representative genes to study by RT-qPCR their induction kinetics and specificity after independent injections of each partner. We showed that both X. nematophila and S. carpocapsae participate in the induction of stable immune responses to the complex. While X. nematophila mainly induces genes classically involved in antibacterial responses, S. carpocapsae induces lectins and genes involved in melanization and encapsulation. We discuss putative relationships between these differential inductions and the pathogen immunosuppressive strategies.
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Affiliation(s)
- Louise Huot
- DGIMI, Univ Montpellier, INRAE, Montpellier, France
| | | | - Sylvie Pagès
- DGIMI, Univ Montpellier, INRAE, Montpellier, France
| | | | | | - Nicolas Nègre
- DGIMI, Univ Montpellier, INRAE, Montpellier, France.
| | - Bernard Duvic
- DGIMI, Univ Montpellier, INRAE, Montpellier, France.
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9
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Younes S, Al-Sulaiti A, Nasser EAA, Najjar H, Kamareddine L. Drosophila as a Model Organism in Host-Pathogen Interaction Studies. Front Cell Infect Microbiol 2020; 10:214. [PMID: 32656090 PMCID: PMC7324642 DOI: 10.3389/fcimb.2020.00214] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Accepted: 04/20/2020] [Indexed: 12/29/2022] Open
Abstract
Owing to the genetic similarities and conserved pathways between a fruit fly and mammals, the use of the Drosophila model as a platform to unveil novel mechanisms of infection and disease progression has been justified and widely instigated. Gaining proper insight into host-pathogen interactions and identifying chief factors involved in host defense and pathogen virulence in Drosophila serves as a foundation to establish novel strategies for infectious disease prevention and control in higher organisms, including humans.
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Affiliation(s)
- Salma Younes
- Biomedical Sciences Department, College of Health Sciences, QU Health, Qatar University, Doha, Qatar
| | - Asma Al-Sulaiti
- Biomedical Sciences Department, College of Health Sciences, QU Health, Qatar University, Doha, Qatar
| | | | - Hoda Najjar
- Biomedical Sciences Department, College of Health Sciences, QU Health, Qatar University, Doha, Qatar
| | - Layla Kamareddine
- Biomedical Sciences Department, College of Health Sciences, QU Health, Qatar University, Doha, Qatar
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10
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Sanda NB, Hou B, Muhammad A, Ali H, Hou Y. Exploring the Role of Relish on Antimicrobial Peptide Expressions (AMPs) Upon Nematode-Bacteria Complex Challenge in the Nipa Palm Hispid Beetle, Octodonta nipae Maulik (Coleoptera: Chrysomelidae). Front Microbiol 2019; 10:2466. [PMID: 31736908 PMCID: PMC6834688 DOI: 10.3389/fmicb.2019.02466] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Accepted: 10/15/2019] [Indexed: 11/13/2022] Open
Abstract
The humoral immune responses of the nipa palm hispid beetle Octodonta nipae involves the inducible expression of the genes coding for antimicrobial peptides (AMPs) which are mediated by immune deficiency signaling pathways. In insects, the nuclear factor-κB (NF-κB) transcription factor, Relish, has been shown to regulate AMP gene expressions upon microbial infections. Here, we dissect the expression patterns of some AMPs in O. nipae during infections by entomopathogenic nematodes (EPNs) and their symbionts, before and after Relish knock down. Our results indicate that, prior to gene silencing, the AMPs attacin C1, attacin C2, and defensin 2B were especially expressed to great extents in the insects challenged with the nematodes Steinernema carpocapsae and Heterorhabditis bacteriophora as well as with their respective symbionts Xenorhabdus nematophila and Photorhabdus luminescens. The study also established the partial sequence of OnRelish/NF-κB p110 subunit in O. nipae, with an open reading frame coding for a protein with 102 amino acid residues. A typical Death domain-containing protein was detected (as seen in Drosophila) at the C-terminus of the protein. Phylogenetic analysis revealed that in O. nipae, Relish is clustered with registered Relish/NF-κB p110 proteins from other species of insect especially Leptinotarsa decemlineata from the same order Coleoptera. Injection of OnRelish dsRNA remarkably brought down the expression of OnRelish and also reduced the magnitude of transcription of attacin C1 and defensin 2B upon S. carpocapsae and H. bacteriophora and their symbionts infections. Altogether, our data unveil the expression pattern of OnRelish as well as that of some AMP genes it influences during immune responses of O. nipae against EPNs and their symbionts.
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Affiliation(s)
- Nafiu Bala Sanda
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Department of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, China
- Department of Crop Protection, Faculty of Agriculture, Bayero University Kano, Kano, Nigeria
| | - Bofeng Hou
- Department of Entomology, College of Plant Protection, Nanjing Agricultural University, Nanjing, China
| | - Abrar Muhammad
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Department of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Habib Ali
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Department of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, China
- Department of Entomology, University of Agriculture Faisalabad, Okara, Pakistan
| | - Youming Hou
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Department of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, China
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11
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Kenney E, Hawdon JM, O'Halloran D, Eleftherianos I. Heterorhabditis bacteriophora Excreted-Secreted Products Enable Infection by Photorhabdus luminescens Through Suppression of the Imd Pathway. Front Immunol 2019; 10:2372. [PMID: 31636642 PMCID: PMC6787769 DOI: 10.3389/fimmu.2019.02372] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2019] [Accepted: 09/20/2019] [Indexed: 12/14/2022] Open
Abstract
Upon entering the hemocoel of its insect host, the entomopathogenic nematode Heterorhabditis bacteriophora releases its symbiotic bacteria Photorhabdus luminescens, which is also a strong insect pathogen. P. luminescens is known to suppress the insect immune response independently following its release, but the nematode appears to enact its own immunosuppressive mechanisms during the earliest phases of an infection. H. bacteriophora was found to produce a unique set of excreted-secreted proteins in response to host hemolymph, and while basal secretions are immunogenic with regard to Diptericin expression through the Imd pathway, host-induced secretions suppress this expression to a level below that of controls in Drosophila melanogaster. This effect is consistent in adults, larvae, and isolated larval fat bodies, and the magnitude of suppression is dose-dependent. By reducing the expression of Diptericin, an antimicrobial peptide active against Gram-negative bacteria, the activated excreted-secreted products enable a more rapid propagation of P. luminescens that corresponds to more rapid host mortality. The identification and isolation of the specific proteins responsible for this suppression represents an exciting field of study with potential for enhancing the biocontrol of insect pests and treatment of diseases associated with excessive inflammation.
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Affiliation(s)
- Eric Kenney
- Infection and Innate Immunity Lab, Department of Biological Sciences, George Washington University, Washington, DC, United States
| | - John M Hawdon
- Department of Microbiology, Immunology, and Tropical Medicine, George Washington University, Washington, DC, United States
| | - Damien O'Halloran
- Infection and Innate Immunity Lab, Department of Biological Sciences, George Washington University, Washington, DC, United States.,Institute for Neuroscience, Department of Biological Sciences, George Washington University, Washington, DC, United States
| | - Ioannis Eleftherianos
- Infection and Innate Immunity Lab, Department of Biological Sciences, George Washington University, Washington, DC, United States
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12
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Spodoptera frugiperda transcriptional response to infestation by Steinernema carpocapsae. Sci Rep 2019; 9:12879. [PMID: 31501491 PMCID: PMC6733877 DOI: 10.1038/s41598-019-49410-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2019] [Accepted: 08/24/2019] [Indexed: 12/28/2022] Open
Abstract
Steinernema carpocapsae is an entomopathogenic nematode (EPN) used in biological control of agricultural pest insects. It enters the hemocoel of its host via the intestinal tract and releases its symbiotic bacterium Xenorhabdus nematophila. In order to improve our knowledge about the physiological responses of its different hosts, we examined the transcriptional responses to EPN infestation of the fat body, the hemocytes and the midgut in the lepidopteran pest Spodoptera frugiperda. The tissues poorly respond to the infestation at an early time post-infestation of 8 h with only 5 genes differentially expressed in the fat body of the caterpillars. Strong transcriptional responses are observed at a later time point of 15 h post-infestation in all three tissues. Few genes are differentially expressed in the midgut but tissue-specific panels of induced metalloprotease inhibitors, immune receptors and antimicrobial peptides together with several uncharacterized genes are up-regulated in the fat body and the hemocytes. Among the most up-regulated genes, we identified new potential immune effectors, unique to Lepidoptera, which show homology with bacterial genes of unknown function. Altogether, these results pave the way for further functional studies of the responsive genes' involvement in the interaction with the EPN.
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13
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Participation of the Serine Protease Jonah66Ci in the Drosophila Antinematode Immune Response. Infect Immun 2019; 87:IAI.00094-19. [PMID: 31182620 DOI: 10.1128/iai.00094-19] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Accepted: 05/29/2019] [Indexed: 01/27/2023] Open
Abstract
Serine proteases and serine protease homologs form the second largest gene family in the Drosophila melanogaster genome. Certain genes in the Jonah multigene family encoding serine proteases have been implicated in the fly antiviral immune response. Here, we report the involvement of Jonah66Ci in the Drosophila immune defense against Steinernema carpocapsae nematode infection. We find that Drosophila Jonah66Ci is upregulated in response to symbiotic (carrying the mutualistic bacterium Xenorhabdus nematophila) or axenic (lacking Xenorhabdus) Steinernema nematodes and is expressed exclusively in the gut of Drosophila larvae. Inactivation of Jonah66Ci provides a survival advantage to larvae against axenic nematodes and results in differential expression of Toll and Imd pathway effector genes, specifically in the gut. Also, inactivation of Jonah66Ci increases the numbers of enteroendocrine and mitotic cells in the gut of uninfected larvae, and infection with Steinernema nematodes reduces their numbers, whereas the numbers of intestinal stem cells are unaffected by nematode infection. Jonah66Ci knockdown further reduces nitric oxide levels in response to infection with symbiotic Steinernema nematodes. Finally, we show that Jonah66Ci knockdown does not alter the feeding rates of uninfected Drosophila larvae; however, infection with axenic Steinernema nematodes lowers larval feeding. In conclusion, we report that Jonah66Ci participates in maintaining homeostasis of certain physiological processes in Drosophila larvae in the context of Steinernema nematode infection. Similar findings will take us a step further toward understanding the molecular and physiological mechanisms that take place during parasitic nematode infection in insects.
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Chevée V, Sachar U, Yadav S, Heryanto C, Eleftherianos I. The peptidoglycan recognition protein PGRP-LE regulates the Drosophila immune response against the pathogen Photorhabdus. Microb Pathog 2019; 136:103664. [PMID: 31404632 DOI: 10.1016/j.micpath.2019.103664] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Revised: 08/09/2019] [Accepted: 08/09/2019] [Indexed: 12/15/2022]
Abstract
Photorhabdus bacteria are potent pathogens of insects and humans. To elucidate the infection strategies Photorhabdus employs to subvert the host innate immune response, it is critical to use model organisms that permit the genetic dissection of the dynamics involved in host-pathogen interactions. Here, we employed the fruit fly Drosophila melanogaster to interrogate the role of the immune deficiency (Imd) pathway receptor peptidoglycan recognition protein LE (PGRP-LE) in the regulation of the fly's response to the insect pathogen Photorhabdus luminescens and the insect/human pathogen P. asymbiotica. We show that PGRP-LE is upregulated in response to injection of Photorhabdus bacteria in background control flies, and that loss-of-function PGRP-LE mutant flies are more sensitive specifically to P. luminescens infection and harbor a higher bacterial burden of this species compared to background controls. Also, our results indicate that the absence of functional PGRP-LE alters the transcriptional pathway activity of Imd and Jnk signaling upon infection with P. asymbiotica, while infection with P. luminescens modifies the activity of Jak/Stat signaling. These findings denote the participation of the PGRP-LE receptor in the response of D. melanogaster to Photorhabdus challenge and contribute to a better understanding of pathogen detection and host immune regulation against virulent microbial invaders.
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Affiliation(s)
- Victoria Chevée
- Infection and Innate Immunity Lab, Department of Biological Sciences, 800 22nd Street NW, Washington, DC, 200 52, USA
| | - Upasana Sachar
- Infection and Innate Immunity Lab, Department of Biological Sciences, 800 22nd Street NW, Washington, DC, 200 52, USA
| | - Shruti Yadav
- Infection and Innate Immunity Lab, Department of Biological Sciences, 800 22nd Street NW, Washington, DC, 200 52, USA
| | - Christa Heryanto
- Infection and Innate Immunity Lab, Department of Biological Sciences, 800 22nd Street NW, Washington, DC, 200 52, USA
| | - Ioannis Eleftherianos
- Infection and Innate Immunity Lab, Department of Biological Sciences, 800 22nd Street NW, Washington, DC, 200 52, USA.
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Harsh S, Heryanto C, Eleftherianos I. Intestinal lipid droplets as novel mediators of host-pathogen interaction in Drosophila. Biol Open 2019; 8:bio.039040. [PMID: 31278163 PMCID: PMC6679391 DOI: 10.1242/bio.039040] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Lipid droplets (LDs) are lipid-carrying multifunctional organelles, which might also interact with pathogens and influence the host immune response. However, the exact nature of these interactions remains currently unexplored. Here we show that systemic infection of Drosophila adult flies with non-pathogenic Escherichia coli, the extracellular bacterial pathogen Photorhabdus luminescens or the facultative intracellular pathogen Photorhabdus asymbiotica results in intestinal steatosis marked by lipid accumulation in the midgut. Accumulation of LDs in the midgut also correlates with increased whole-body lipid levels characterized by increased expression of genes regulating lipogenesis. The lipid-enriched midgut further displays reduced expression of the enteroendocrine-secreted hormone, Tachykinin. The observed lipid accumulation requires the Gram-negative cell wall pattern recognition molecule, PGRP-LC, but not PGRP-LE, for the humoral immune response. Altogether, our findings indicate that Drosophila LDs are inducible organelles, which can serve as markers for inflammation and, depending on the nature of the challenge, they can dictate the outcome of the infection. Summary: Lipid droplets are inducible organelles, act as inflammatory markers and, depending on the nature of challenge, can dictate the outcome of the infection.
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Affiliation(s)
- Sneh Harsh
- Department of Biological Sciences, Institute for Biomedical Sciences, The George Washington University, Washington DC 20052, USA
| | - Christa Heryanto
- Department of Biological Sciences, Institute for Biomedical Sciences, The George Washington University, Washington DC 20052, USA
| | - Ioannis Eleftherianos
- Department of Biological Sciences, Institute for Biomedical Sciences, The George Washington University, Washington DC 20052, USA
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Patrnogic J, Castillo JC, Shokal U, Yadav S, Kenney E, Heryanto C, Ozakman Y, Eleftherianos I. Pre-exposure to non-pathogenic bacteria does not protect Drosophila against the entomopathogenic bacterium Photorhabdus. PLoS One 2018; 13:e0205256. [PMID: 30379824 PMCID: PMC6209181 DOI: 10.1371/journal.pone.0205256] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Accepted: 09/22/2018] [Indexed: 01/27/2023] Open
Abstract
Immune priming in insects involves an initial challenge with a non-pathogenic microbe or exposure to a low dose of pathogenic microorganisms, which provides a certain degree of protection against a subsequent pathogenic infection. The protective effect of insect immune priming has been linked to the activation of humoral or cellular features of the innate immune response during the preliminary challenge, and these effects might last long enough to promote the survival of the infected animal. The fruit fly Drosophila melanogaster is a superb model to dissect immune priming processes in insects due to the availability of molecular and genetic tools, and the comprehensive understanding of the innate immune response in this organism. Previous investigations have indicated that the D. melanogaster immune system can be primed efficiently. Here we have extended these studies by examining the result of immune priming against two potent entomopathogenic bacteria, Photorhabdus luminescens and P. asymbiotica. We have found that rearing D. melanogaster on diet containing a non-pathogenic strain of Escherichia coli alone or in combination with Micrococcus luteus upregulates the antibacterial peptide immune response in young adult flies, but it does not prolong fly life span. Also, subsequent intrathoracic injection with P. luminescens or P. asymbiotica triggers the Immune deficiency and Toll signaling pathways in flies previously exposed to a live or heat-killed mix of the non-pathogenic bacteria, but the immune activation fails to promote fly survival against the pathogens. These findings suggest that immune priming in D. melanogaster, and probably in other insects, is determined by the type of microbes involved as well as the mode of microbial exposure, and possibly requires a comprehensive and precise alteration of immune signaling and function to provide efficient protection against pathogenic infection.
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Affiliation(s)
- Jelena Patrnogic
- Infection and Innate Immunity Lab, Department of Biological Sciences, George Washington University, Washington, District of Columbia, United States of America
| | - Julio Cesar Castillo
- Infection and Innate Immunity Lab, Department of Biological Sciences, George Washington University, Washington, District of Columbia, United States of America
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland, United States of America
| | - Upasana Shokal
- Infection and Innate Immunity Lab, Department of Biological Sciences, George Washington University, Washington, District of Columbia, United States of America
| | - Shruti Yadav
- Infection and Innate Immunity Lab, Department of Biological Sciences, George Washington University, Washington, District of Columbia, United States of America
| | - Eric Kenney
- Infection and Innate Immunity Lab, Department of Biological Sciences, George Washington University, Washington, District of Columbia, United States of America
| | - Christa Heryanto
- Infection and Innate Immunity Lab, Department of Biological Sciences, George Washington University, Washington, District of Columbia, United States of America
| | - Yaprak Ozakman
- Infection and Innate Immunity Lab, Department of Biological Sciences, George Washington University, Washington, District of Columbia, United States of America
| | - Ioannis Eleftherianos
- Infection and Innate Immunity Lab, Department of Biological Sciences, George Washington University, Washington, District of Columbia, United States of America
- * E-mail:
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Entomopathogenic nematode Steinernema carpocapsae surpasses the cellular immune responses of the hispid beetle, Octodonta nipae (Coleoptera: Chrysomelidae). Microb Pathog 2018; 124:337-345. [PMID: 30172903 DOI: 10.1016/j.micpath.2018.08.063] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Revised: 08/29/2018] [Accepted: 08/29/2018] [Indexed: 12/29/2022]
Abstract
The Nipa palm hispid, Octodonta nipae (Maulik) is an important invasive pest of palm trees particularly in Southern China. How this beetle interacts with invading pathogens via its immune system remains to be dissected. Steinernema carpocapsae is a pathogenic nematode that attacks a number of insects of economic importance. The present study systematically investigates the cellular immune responses of O. nipae against S. carpocapsae infection using combined immunological, biochemical and transcriptomics approaches. Our data reveal that S. carpocapsae efficiently resists being encapsulated and melanized within the host's hemolymph and most of the nematodes were observed moving freely in the hemolymph even at 24 h post incubation. Consistently, isolated cuticles from the parasite also withstand encapsulation by the O. nipae hemocytes at all-time points. However, significant encapsulation and melanization of the isolated cuticles were recorded following heat treatment of the cuticles. The host's phenoloxidase activity was found to be slightly suppressed due to S. carpocapsae infection. Furthermore, the expression levels of some antimicrobial peptide (AMP) genes were significantly up-regulated in the S. carpocapsae-challenged O. nipae. Taken together, our data suggest that S. carpocapsae modulates and surpasses the O. nipae immune responses and hence can serve as an excellent biological control agent of the pest.
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Yadav S, Gupta S, Eleftherianos I. Differential Regulation of Immune Signaling and Survival Response in Drosophila melanogaster Larvae upon Steinernema carpocapsae Nematode Infection. INSECTS 2018; 9:insects9010017. [PMID: 29419764 PMCID: PMC5872282 DOI: 10.3390/insects9010017] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/09/2017] [Revised: 01/27/2018] [Accepted: 02/01/2018] [Indexed: 01/11/2023]
Abstract
Drosophila melanogaster is an excellent model to dissect the molecular components and pathways of the innate anti-pathogen immune response. The nematode parasite Steinernema carpocapsae and its mutualistic bacterium Xenorhabdus nematophila form a complex that is highly pathogenic to insects, including D. melanogaster. We have used symbiotic (carrying X. nematophila) and axenic (lacking X. nematophila) nematodes to probe the regulation of genes belonging to different immune signaling pathways in D. melanogaster larvae and assess the survival response of certain mutants to these pathogens. We found that both types of S. carpocapsae upregulate MyD88 (Toll), but not PGRP-LE (Imd); whereas axenic S. carpocapsae strongly upregulate Wengen (Jnk), Domeless (Jak/Stat), Dawdle (TGFβ, Activin), and Decapentaplegic (TGFβ, BMP). We further found that inactivation of Wengen and Decapentaplegic confers a survival advantage to larvae infected with axenic S. carpocapsae, whereas mutating PGRP-LE promotes the survival of larvae infected with symbiotic nematodes.
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Affiliation(s)
- Shruti Yadav
- Insect Infection and Immunity Lab., Department of Biological Sciences, The George Washington University, Washington, DC 20052, USA.
| | - Sonali Gupta
- Insect Infection and Immunity Lab., Department of Biological Sciences, The George Washington University, Washington, DC 20052, USA.
| | - Ioannis Eleftherianos
- Insect Infection and Immunity Lab., Department of Biological Sciences, The George Washington University, Washington, DC 20052, USA.
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19
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Eleftherianos I, Yadav S, Kenney E, Cooper D, Ozakman Y, Patrnogic J. Role of Endosymbionts in Insect-Parasitic Nematode Interactions. Trends Parasitol 2017; 34:430-444. [PMID: 29150386 DOI: 10.1016/j.pt.2017.10.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2017] [Revised: 09/12/2017] [Accepted: 10/19/2017] [Indexed: 12/12/2022]
Abstract
Endosymbiotic bacteria exist in many animals where they develop relationships that affect certain physiological processes in the host. Insects and their nematode parasites form great models for understanding the genetic and molecular basis of immune and parasitic processes. Both organisms contain endosymbionts that possess the ability to interfere with certain mechanisms of immune function and pathogenicity. This review summarizes recent information on the involvement of insect endosymbionts in the response to parasitic nematode infections, and the influence of nematode endosymbionts on specific aspects of the insect immune system. Analyzing this information will be particularly useful for devising endosymbiont-based strategies to intervene in insect immunity or nematode parasitism for the efficient management of noxious insects in the field.
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Affiliation(s)
- Ioannis Eleftherianos
- Insect Infection and Immunity Laboratory, Department of Biological Sciences, The George Washington University, Science and Engineering Hall, 800 22nd Street NW, Washington, DC 20052, USA.
| | - Shruti Yadav
- Insect Infection and Immunity Laboratory, Department of Biological Sciences, The George Washington University, Science and Engineering Hall, 800 22nd Street NW, Washington, DC 20052, USA
| | - Eric Kenney
- Insect Infection and Immunity Laboratory, Department of Biological Sciences, The George Washington University, Science and Engineering Hall, 800 22nd Street NW, Washington, DC 20052, USA
| | - Dustin Cooper
- Insect Infection and Immunity Laboratory, Department of Biological Sciences, The George Washington University, Science and Engineering Hall, 800 22nd Street NW, Washington, DC 20052, USA
| | - Yaprak Ozakman
- Insect Infection and Immunity Laboratory, Department of Biological Sciences, The George Washington University, Science and Engineering Hall, 800 22nd Street NW, Washington, DC 20052, USA
| | - Jelena Patrnogic
- Insect Infection and Immunity Laboratory, Department of Biological Sciences, The George Washington University, Science and Engineering Hall, 800 22nd Street NW, Washington, DC 20052, USA
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Kausar S, Abbas MN, Qian C, Zhu B, Sun Y, Sun Y, Wang L, Wei G, Maqsood I, Liu CL. Serpin-14 negatively regulates prophenoloxidase activation and expression of antimicrobial peptides in Chinese oak silkworm Antheraea pernyi. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2017; 76:45-55. [PMID: 28545959 DOI: 10.1016/j.dci.2017.05.017] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2017] [Revised: 05/21/2017] [Accepted: 05/21/2017] [Indexed: 06/07/2023]
Abstract
Genes encoding proteins of serpins superfamily are widely distributed in invertebrates. In insects, serpins play important roles in regulating immune responses and other physiological processes. Here, we report the cloning and characterization of cDNA of Apserpin-14 from Chinese oak silkworm (Antheraea pernyi). The Apserpin-14 gene contains 1206 bp open reading frame, encoding a predicted 401 amino acid residue protein. We expressed the recombinant Apserpin-14 protein in Escherichia coli and then purified protein was used to prepare rabbit anti-Apserpin-14 polyclonal antibodies. Quantitative real-time PCR analysis revealed that mRNA level of Apserpin-14 was highest in the fat body, whereas, among developmental stages the 5th instar and pupal stage showed greatest expression. Furthermore, Escherichia coli, Beauveria bassiana, Micrococcus luteus and nuclear polyhedrosis virus challenge enhanced Apserpin-14 transcript in both the fat body and hemocyte. Recombinant Apserpin-14 added to hemolymph inhibited spontaneous melanization and suppressed prophenoloxidase activation stimulated by M. luteus, but did not affect phenoloxidase (PO) activity. Injection of recombinant Apserpin-14 protein into A. pernyi larvae significantly reduced the transcript levels of antimicrobial peptides in the fat body, while its depletion by double stranded RNA enhanced their expression. We concluded that Apserpin-14 likely involved in regulation of proPO activation and production of antimicrobial peptides, implying its important role in the innate immune system of A. pernyi.
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Affiliation(s)
- Saima Kausar
- College of Life Sciences, Anhui Agricultural University, Hefei, 230036, China.
| | | | - Cen Qian
- College of Life Sciences, Anhui Agricultural University, Hefei, 230036, China.
| | - Baojian Zhu
- College of Life Sciences, Anhui Agricultural University, Hefei, 230036, China.
| | - Yu Sun
- College of Life Sciences, Anhui Agricultural University, Hefei, 230036, China.
| | - Yuxuan Sun
- College of Life Sciences, Anhui Agricultural University, Hefei, 230036, China.
| | - Lei Wang
- College of Life Sciences, Anhui Agricultural University, Hefei, 230036, China.
| | - Guoqing Wei
- College of Life Sciences, Anhui Agricultural University, Hefei, 230036, China.
| | - Iram Maqsood
- College of Wildlife Resources, Department of Wildlife Conservation and Utilization, Northeast Forestry University Harbin, China.
| | - Chao-Liang Liu
- College of Life Sciences, Anhui Agricultural University, Hefei, 230036, China.
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Miller CVL, Cotter SC. Resistance and tolerance: The role of nutrients on pathogen dynamics and infection outcomes in an insect host. J Anim Ecol 2017; 87:500-510. [PMID: 28975615 DOI: 10.1111/1365-2656.12763] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2017] [Accepted: 08/11/2017] [Indexed: 11/26/2022]
Abstract
Tolerance and resistance are the two ways in which hosts can lessen the effects of infection. Tolerance aims to minimize the fitness effects resulting from incumbent pathogen populations, whereas resistance aims to reduce the pathogen population size within the host. While environmental impacts on resistance have been extensively, recorded their impacts on variation in tolerance are virtually unexplored. Here, we ask how the environment, namely the host diet, influences the capacity of an organism to tolerate and resist infection, using a model host-parasite system, the burying beetle, Nicrophorus vespilloides and the entomopathogenic bacteria, Photorhabdus luminescens. We first considered dose-responses and pathogen dynamics within the host, and compared our findings to responses known from other host species. We then investigated how investment in tolerance and resistance changed under different nutritional regimes. Beetles were maintained on one of five diets that varied in their ratio of protein to fat for 48 hr and then injected with P. luminescens. Survival was monitored and the phenoloxidase (PO) response and bacterial load at 24-hr postinfection were ascertained. The dose required to kill 50% of individuals in this species was several magnitudes higher than in other species and the bacteria were shown to display massive decreases in population size, in contrast to patterns of proliferation found in other host species. Diet strongly modified host survival after infection, with those on the high fat/low protein diet showing 30% survival at 8 days, vs. almost 0% survival on the low-fat/high-protein diet. However, this was independent of bacterial load or variation in PO, providing evidence for diet-mediated tolerance mechanisms rather than immune-driven resistance. Evolutionary ecology has long focussed on immune resistance when investigating how organisms avoid succumbing to infection. Tolerance of infection has recently become a much more prominent concept and is suggested to be influential in disease dynamics. This is one of the first studies to find diet-mediated tolerance.
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Affiliation(s)
- Charlotte V L Miller
- School of Biological Sciences, Queen's University Belfast, Belfast, UK.,School of Life Sciences, University of Lincoln, Lincoln, UK
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The Global Transcription Factor Lrp Is both Essential for and Inhibitory to Xenorhabdus nematophila Insecticidal Activity. Appl Environ Microbiol 2017; 83:AEM.00185-17. [PMID: 28411220 DOI: 10.1128/aem.00185-17] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2017] [Accepted: 04/06/2017] [Indexed: 01/04/2023] Open
Abstract
In the entomopathogenic bacterium Xenorhabdus nematophila, cell-to-cell variation in the abundance of the Lrp transcription factor leads to virulence modulation; low Lrp levels are associated with a virulent phenotype and suppression of antimicrobial peptides (AMPs) in Manduca sexta insects, while cells that lack lrp or express high Lrp levels are virulence attenuated and elicit AMP expression. To better understand the basis of these phenotypes, we examined X. nematophila strains expressing fixed Lrp levels. Unlike the lrp-null mutant, the high-lrp strain is fully virulent in Drosophila melanogaster, suggesting that these two strains have distinct underlying causes of virulence attenuation in M. sexta Indeed, the lrp-null mutant was defective in cytotoxicity against M. sexta hemocytes relative to that in the high-lrp and low-lrp strains. Further, supernatant derived from the lrp-null mutant but not from the high-lrp strain was defective in inhibiting weight gain when fed to 1st instar M. sexta These data suggest that contributors to the lrp-null mutant virulence attenuation phenotype are the lack of Lrp-dependent cytotoxic and extracellular oral growth inhibitory activities, which may be particularly important for virulence in D. melanogaster In contrast, the high-Lrp strain was sensitive to the antimicrobial peptide cecropin, had a transient survival defect in M. sexta, and had reduced extracellular levels of insecticidal activity, measured by injection of supernatant into 4th instar M. sexta Thus, high-lrp strain virulence attenuation may be explained by its hypersensitivity to M. sexta host immunity and its inability to secrete one or more insecticidal factors.IMPORTANCE Adaptation of a bacterial pathogen to host environments can be achieved through the coordinated regulation of virulence factors that can optimize success under prevailing conditions. In the insect pathogen Xenorhabdus nematophila, the global transcription factor Lrp is necessary for virulence when injected into Manduca sexta or Drosophila melanogaster insect hosts. However, high levels of Lrp, either naturally occurring or artificially induced, cause attenuation of X. nematophila virulence in M. sexta but not D. melanogaster Here, we present evidence suggesting that the underlying cause of high-Lrp-dependent virulence attenuation in M. sexta is hypersensitivity to host immune responses and decreased insecticidal activity and that high-Lrp virulence phenotypes are insect host specific. This knowledge suggests that X. nematophila faces varied challenges depending on the type of insect host it infects and that its success in these environments depends on Lrp-dependent control of a multifactorial virulence repertoire.
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Mouammine A, Pages S, Lanois A, Gaudriault S, Jubelin G, Bonabaud M, Cruveiller S, Dubois E, Roche D, Legrand L, Brillard J, Givaudan A. An antimicrobial peptide-resistant minor subpopulation of Photorhabdus luminescens is responsible for virulence. Sci Rep 2017; 7:43670. [PMID: 28252016 PMCID: PMC5333078 DOI: 10.1038/srep43670] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2016] [Accepted: 01/27/2017] [Indexed: 11/09/2022] Open
Abstract
Some of the bacterial cells in isogenic populations behave differently from others. We describe here how a new type of phenotypic heterogeneity relating to resistance to cationic antimicrobial peptides (CAMPs) is determinant for the pathogenic infection process of the entomopathogenic bacterium Photorhabdus luminescens. We demonstrate that the resistant subpopulation, which accounts for only 0.5% of the wild-type population, causes septicemia in insects. Bacterial heterogeneity is driven by the PhoPQ two-component regulatory system and expression of pbgPE, an operon encoding proteins involved in lipopolysaccharide (LPS) modifications. We also report the characterization of a core regulon controlled by the DNA-binding PhoP protein, which governs virulence in P. luminescens. Comparative RNAseq analysis revealed an upregulation of marker genes for resistance, virulence and bacterial antagonism in the pre-existing resistant subpopulation, suggesting a greater ability to infect insect prey and to survive in cadavers. Finally, we suggest that the infection process of P. luminescens is based on a bet-hedging strategy to cope with the diverse environmental conditions experienced during the lifecycle.
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Affiliation(s)
| | - Sylvie Pages
- DGIMI, INRA, Univ. Montpellier, Montpellier, France
| | - Anne Lanois
- DGIMI, INRA, Univ. Montpellier, Montpellier, France
| | | | | | | | - Stéphane Cruveiller
- Laboratoire d'Analyse Bioinformatique en Génomique et Métabolisme, CEA, Genoscope &CNRS, Evry, France
| | - Emeric Dubois
- MGX-Montpellier GenomiX, c/o IGF, Montpellier, France
| | - David Roche
- Laboratoire d'Analyse Bioinformatique en Génomique et Métabolisme, CEA, Genoscope &CNRS, Evry, France
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Shokal U, Eleftherianos I. Thioester-Containing Protein-4 Regulates the Drosophila Immune Signaling and Function against the Pathogen Photorhabdus. J Innate Immun 2016; 9:83-93. [PMID: 27771727 DOI: 10.1159/000450610] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2016] [Accepted: 09/06/2016] [Indexed: 12/18/2022] Open
Abstract
Despite important progress in identifying the molecules that participate in the immune response of Drosophila melanogaster to microbial infections, the involvement of thioester-containing proteins (TEPs) in the antibacterial immunity of the fly is not fully clarified. Previous studies mostly focused on identifying the function of TEP2, TEP3 and TEP6 molecules in the D. melanogaster immune system. Here, we investigated the role of TEP4 in the regulation and function of D. melanogaster host defense against 2 virulent pathogens from the genus Photorhabdus, i.e. the insect pathogenic bacterium Photorhabdus luminescens and the emerging human pathogen P. asymbiotica. We demonstrate that Tep4 is strongly upregulated in adult flies following the injection of Photorhabdus bacteria. We also show that Tep4 loss-of-function mutants are resistant to P. luminescens but not to P. asymbiotica infection. In addition, we find that inactivation of Tep4 results in the upregulation of the Toll and Imd immune pathways, and the downregulation of the Jak/Stat and Jnk pathways upon Photorhabdus infection. We document that loss of Tep4 promotes melanization and phenoloxidase activity in the mutant flies infected with Photorhabdus. Together, these findings generate novel insights into the immune role of TEP4 as a regulator and effector of the D. melanogaster antibacterial immune response.
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Affiliation(s)
- Upasana Shokal
- Department of Biological Sciences, Institute for Biomedical Sciences, The George Washington University, Washington, D.C., USA
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25
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Insect Immunity to Entomopathogenic Nematodes and Their Mutualistic Bacteria. Curr Top Microbiol Immunol 2016; 402:123-156. [PMID: 27995342 DOI: 10.1007/82_2016_52] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Entomopathogenic nematodes are important organisms for the biological control of insect pests and excellent models for dissecting the molecular basis of the insect immune response against both the nematode parasites and their mutualistic bacteria. Previous research involving the use of various insects has found distinct differences in the number and nature of immune mechanisms that are activated in response to entomopathogenic nematode parasites containing or lacking their associated bacteria. Recent studies using model insects have started to reveal the identity of certain molecules with potential anti-nematode or antibacterial activity as well as the molecular components that nematodes and their bacteria employ to evade or defeat the insect immune system. Identification and characterization of the genes that regulate the insect immune response to nematode-bacteria complexes will contribute significantly to the development of improved practices to control insects of agricultural and medical importance, and potentially nematode parasites that infect mammals, perhaps even humans.
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Effects of an entomopathogen nematode on the immune response of the insect pest red palm weevil: Focus on the host antimicrobial response. J Invertebr Pathol 2016; 133:110-9. [DOI: 10.1016/j.jip.2015.11.001] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2015] [Revised: 11/02/2015] [Accepted: 11/04/2015] [Indexed: 01/26/2023]
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Yadav S, Shokal U, Forst S, Eleftherianos I. An improved method for generating axenic entomopathogenic nematodes. BMC Res Notes 2015; 8:461. [PMID: 26386557 PMCID: PMC4575472 DOI: 10.1186/s13104-015-1443-y] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2015] [Accepted: 09/11/2015] [Indexed: 12/19/2022] Open
Abstract
Background Steinernema carpocapsae are parasitic nematodes that invade and kill insects. The nematodes are mutualistically associated with the bacteria Xenorhabdus nematophila and together form an excellent model to study pathogen infection processes and host anti-nematode/antibacterial immune responses. To determine the contribution of S. carpocapsae and their associated X. nematophila to the successful infection of insects as well as to investigate the interaction of each mutualistic partner with the insect immune system, it is important to develop and establish robust methods for generating nematodes devoid of their bacteria. Findings To produce S. carpocapsae nematodes without their associated X. nematophila bacteria, we have modified a previous method, which involves the use of a X. nematophilarpoS mutant strain that fails to colonize the intestine of the worms. We confirmed the absence of bacteria in the nematodes using a molecular diagnostic and two rounds of an axenicity assay involving appropriate antibiotics and nematode surface sterilization. We used axenic and symbiotic S. carpocapsae to infect Drosophila melanogaster larvae and found that both types of nematodes were able to cause insect death at similar rates. Conclusion Generation of entomopathogenic nematodes lacking their mutualistic bacteria provides an excellent tool to dissect the molecular and genetic basis of nematode parasitism and to identify the insect host immune factors that participate in the immune response against nematode infections.
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Affiliation(s)
- Shruti Yadav
- Insect Infection and Immunity Lab, Department of Biological Sciences, Institute for Biomedical Sciences, The George Washington University, Washington DC, USA.
| | - Upasana Shokal
- Insect Infection and Immunity Lab, Department of Biological Sciences, Institute for Biomedical Sciences, The George Washington University, Washington DC, USA.
| | - Steven Forst
- Department of Biological Sciences, University of Wisconsin-Milwaukee, Milwaukee, WI, USA.
| | - Ioannis Eleftherianos
- Insect Infection and Immunity Lab, Department of Biological Sciences, Institute for Biomedical Sciences, The George Washington University, Washington DC, USA.
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Peña JM, Carrillo MA, Hallem EA. Variation in the susceptibility of Drosophila to different entomopathogenic nematodes. Infect Immun 2015; 83:1130-8. [PMID: 25561714 PMCID: PMC4333445 DOI: 10.1128/iai.02740-14] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2014] [Accepted: 12/29/2014] [Indexed: 12/11/2022] Open
Abstract
Entomopathogenic nematodes (EPNs) in the genera Heterorhabditis and Steinernema are lethal parasites of insects that are of interest as models for understanding parasite-host interactions and as biocontrol agents for insect pests. EPNs harbor a bacterial endosymbiont in their gut that assists in insect killing. EPNs are capable of infecting and killing a wide range of insects, yet how the nematodes and their bacterial endosymbionts interact with the insect immune system is poorly understood. Here, we develop a versatile model system for understanding the insect immune response to parasitic nematode infection that consists of seven species of EPNs as model parasites and five species of Drosophila fruit flies as model hosts. We show that the EPN Steinernema carpocapsae, which is widely used for insect control, is capable of infecting and killing D. melanogaster larvae. S. carpocapsae is associated with the bacterium Xenorhabdus nematophila, and we show that X. nematophila induces expression of a subset of antimicrobial peptide genes and suppresses the melanization response to the nematode. We further show that EPNs vary in their virulence toward D. melanogaster and that Drosophila species vary in their susceptibilities to EPN infection. Differences in virulence among different EPN-host combinations result from differences in both rates of infection and rates of postinfection survival. Our results establish a powerful model system for understanding mechanisms of host-parasite interactions and the insect immune response to parasitic nematode infection.
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Affiliation(s)
- Jennifer M Peña
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, Los Angeles, California, USA
| | - Mayra A Carrillo
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, Los Angeles, California, USA
| | - Elissa A Hallem
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, Los Angeles, California, USA
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Eom S, Park Y, Kim Y. Sequential immunosuppressive activities of bacterial secondary metabolites from the entomopahogenic bacterium Xenorhabdus nematophila. J Microbiol 2014; 52:161-8. [DOI: 10.1007/s12275-014-3251-9] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2013] [Revised: 08/19/2013] [Accepted: 08/23/2013] [Indexed: 01/29/2023]
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Panayidou S, Ioannidou E, Apidianakis Y. Human pathogenic bacteria, fungi, and viruses in Drosophila: disease modeling, lessons, and shortcomings. Virulence 2014; 5:253-69. [PMID: 24398387 DOI: 10.4161/viru.27524] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Drosophila has been the invertebrate model organism of choice for the study of innate immune responses during the past few decades. Many Drosophila-microbe interaction studies have helped to define innate immunity pathways, and significant effort has been made lately to decipher mechanisms of microbial pathogenesis. Here we catalog 68 bacterial, fungal, and viral species studied in flies, 43 of which are relevant to human health. We discuss studies of human pathogens in flies revealing not only the elicitation and avoidance of immune response but also mechanisms of tolerance, host tissue homeostasis, regeneration, and predisposition to cancer. Prominent among those is the emerging pattern of intestinal regeneration as a defense response induced by pathogenic and innocuous bacteria. Immunopathology mechanisms and many microbial virulence factors have been elucidated, but their relevance to human health conventionally necessitates validation in mammalian models of infection.
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Affiliation(s)
- Stavria Panayidou
- Department of Biological Sciences; University of Cyprus; Nicosia, Cyprus
| | - Eleni Ioannidou
- Department of Biological Sciences; University of Cyprus; Nicosia, Cyprus
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The genetic basis of the symbiosis between Photorhabdus and its invertebrate hosts. ADVANCES IN APPLIED MICROBIOLOGY 2014; 88:1-29. [PMID: 24767424 DOI: 10.1016/b978-0-12-800260-5.00001-2] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Photorhabdus is a pathogen of insects that also maintains a mutualistic association with nematodes from the family Heterorhabditis. Photorhabdus colonizes the gut of the infective juvenile (IJ) stage of the nematode. The IJ infects an insect and regurgitates the bacteria and the bacteria reproduce to kill the insect. The nematodes feed on the resulting bacterial biomass until a new generation of IJs emerges from the insect cadaver. Therefore, during its life cycle, Photorhabdus must (1) kill the insect host, (2) support nematode growth and development, and (3) be able to colonize the new generation of IJs. In this review, functional genomic studies that have been aimed at understanding the molecular mechanisms underpinning each of these roles will be discussed. These studies have begun to reveal that distinct gene sets may be required for each of these interactions, suggesting that there is only a minimal genetic overlap between pathogenicity and mutualism in Photorhabdus.
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Casanova-Torres ÁM, Goodrich-Blair H. Immune Signaling and Antimicrobial Peptide Expression in Lepidoptera. INSECTS 2013; 4:320-38. [PMID: 25861461 PMCID: PMC4386667 DOI: 10.3390/insects4030320] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/01/2013] [Revised: 06/21/2013] [Accepted: 06/21/2013] [Indexed: 02/06/2023]
Abstract
Many lepidopteran insects are agricultural pests that affect stored grains, food and fiber crops. These insects have negative ecological and economic impacts since they lower crop yield, and pesticides are expensive and can have off-target effects on beneficial arthropods. A better understanding of lepidopteran immunity will aid in identifying new targets for the development of specific insect pest management compounds. A fundamental aspect of immunity, and therefore a logical target for control, is the induction of antimicrobial peptide (AMP) expression. These peptides insert into and disrupt microbial membranes, thereby promoting pathogen clearance and insect survival. Pathways leading to AMP expression have been extensively studied in the dipteran Drosophila melanogaster. However, Diptera are an important group of pollinators and pest management strategies that target their immune systems is not recommended. Recent advances have facilitated investigation of lepidopteran immunity, revealing both conserved and derived characteristics. Although the general pathways leading to AMP expression are conserved, specific components of these pathways, such as recognition proteins have diverged. In this review we highlight how such comparative immunology could aid in developing pest management strategies that are specific to agricultural insect pests.
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Hwang J, Park Y, Kim Y, Hwang J, Lee D. An entomopathogenic bacterium, Xenorhabdus nematophila, suppresses expression of antimicrobial peptides controlled by Toll and Imd pathways by blocking eicosanoid biosynthesis. ARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY 2013; 83:151-169. [PMID: 23740621 DOI: 10.1002/arch.21103] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Immune-associated genes of the beet armyworm, Spodoptera exigua, were predicted from 454 pyrosequencing transcripts of hemocytes collected from fifth instar larvae challenged with bacteria. Out of 22,551 contigs and singletons, 36% of the transcripts had at least one significant hit (E-value cutoff of 1e-20) and used to predict immune-associated genes implicated in pattern recognition, prophenoloxidase activation, intracellular signaling, and antimicrobial peptides (AMPs). Immune signaling and AMP genes were further confirmed in their expression patterns in response to different types of microbial challenge. To discriminate the AMP expression signaling between Toll and Imd pathways, RNA interference was applied to specifically knockdown each signal pathway; the separate silencing treatments resulted in differential suppression of AMP genes. An entomopathogenic bacterium, Xenorhabdus nematophila, suppressed expression of most AMP genes controlled by Toll and Imd pathways, while challenge with heat-killed X. nematophila induced expression of all AMPs in experimental larvae. Benzylideneacetone (BZA), a metabolite of X. nematophila, suppressed the AMP gene inductions when it was co-injected with the heat-killed X. nematophila. However, arachidonic acid, a catalytic product of PLA2 , significantly reversed the inhibitory effect of BZA on the AMP gene expression. This study suggests that X. nematophila suppresses AMP production controlled by Toll and Imd pathways by inhibiting eicosanoid biosynthesis in S. exigua.
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Affiliation(s)
- Jihyun Hwang
- Department of Bioresource Sciences, Andong National University, Andong, Korea
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Castillo JC, Shokal U, Eleftherianos I. Immune gene transcription in Drosophila adult flies infected by entomopathogenic nematodes and their mutualistic bacteria. JOURNAL OF INSECT PHYSIOLOGY 2013; 59:179-85. [PMID: 22902989 DOI: 10.1016/j.jinsphys.2012.08.003] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2012] [Revised: 08/02/2012] [Accepted: 08/03/2012] [Indexed: 05/08/2023]
Abstract
Despite impressive advances in the broad field of insect innate immunity, our understanding of the molecular basis of insect immune responses to nematode infections remains incomplete. Here we have investigated the transcriptional induction of immune pathway genes in the fruit fly Drosophila melanogaster upon infection with the entomopathogenic (or insect pathogenic) nematodes Heterorhabditis bacteriophora and their mutualistic bacteria Photorhabdus luminescens, either collectively or separately. We show that in most cases, infection of wild-type adult flies with Heterorhabditis nematodes carrying or lacking mutualistic Photorhabdus bacteria results in the up-regulation of genes in the Toll, Imd, JAK/STAT, JNK and TGF-beta pathways. We also find that direct injection of Photorhabdus bacteria into flies fails to induce the transcription of antimicrobial peptide genes and stress-related genes in Drosophila. These results suggest that Heterorhabditis nematodes and their associated Photorhabdus bacteria employ distinct strategies to evade the Drosophila immune response and establish infection.
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Affiliation(s)
- J C Castillo
- Insect Infection and Immunity Lab, Department of Biological Sciences, Institute for Biomedical Sciences, Columbian College of Arts and Sciences, The George Washington University, Washington, DC 20052, USA
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Abstract
The deleterious and sometimes fatal outcomes of bacterial infectious diseases are the net result of the interactions between the pathogen and the host, and the genetically tractable fruit fly, Drosophila melanogaster, has emerged as a valuable tool for modeling the pathogen-host interactions of a wide variety of bacteria. These studies have revealed that there is a remarkable conservation of bacterial pathogenesis and host defence mechanisms between higher host organisms and Drosophila. This review presents an in-depth discussion of the Drosophila immune response, the Drosophila killing model, and the use of the model to examine bacterial-host interactions. The recent introduction of the Drosophila model into the oral microbiology field is discussed, specifically the use of the model to examine Porphyromonas gingivalis-host interactions, and finally the potential uses of this powerful model system to further elucidate oral bacterial-host interactions are addressed.
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Affiliation(s)
- Christina O Igboin
- Division of Oral Biology, College of Dentistry, The Ohio State University, Columbus, Ohio, USA
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Insect immune responses to nematode parasites. Trends Parasitol 2011; 27:537-47. [PMID: 21982477 DOI: 10.1016/j.pt.2011.09.001] [Citation(s) in RCA: 113] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2011] [Revised: 09/01/2011] [Accepted: 09/08/2011] [Indexed: 12/16/2022]
Abstract
Host innate immunity plays a central role in detecting and eliminating microbial pathogenic infections in both vertebrate and invertebrate animals. Entomopathogenic or insect pathogenic nematodes are of particular importance for the control of insect pests and vectors of pathogens, while insect-borne nematodes cause serious diseases in humans. Recent work has begun to use the power of insect models to investigate host-nematode interactions and uncover host antiparasitic immune reactions. This review describes recent findings on innate immune evasion strategies of parasitic nematodes and host cellular and humoral responses to the infection. Such information can be used to model diseases caused by human parasitic nematodes and provide clues indicating directions for research into the interplay between vector insects and their invading tropical parasites.
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