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Chauhan M, Martinak PE, Hollenberg BM, Goodman AG. Drosophila melanogaster Toll-9 elicits antiviral immunity against Drosophila C virus. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.19.599730. [PMID: 38948804 PMCID: PMC11212974 DOI: 10.1101/2024.06.19.599730] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/02/2024]
Abstract
The Toll pathway plays a pivotal role in innate immune responses against pathogens. The evolutionary conserved pathogen recognition receptors (PRRs), including Toll like receptors (TLRs), play a crucial role in recognition of pathogen associated molecular patterns (PAMPs). The Drosophila genome encodes nine Toll receptors that are orthologous to mammalian TLRs. While mammalian TLRs directly recognize PAMPs, most Drosophila Tolls recognize the proteolytically cleaved ligand Spätzle to activate downstream signaling cascades. In this study, we demonstrated that Toll-9 is crucial for antiviral immunity against Drosophila C virus (DCV), a natural pathogen of Drosophila . A transposable element insertion in the Toll-9 gene renders the flies more susceptible to DCV. The stable expression of Toll-9 in S2 cells confers resistance against DCV infection by upregulation of the RNAi pathway. Toll-9 promotes the dephosphorylation of AKT, resulting in the induction of antiviral RNAi genes to inhibit DCV replication. Toll-9 localizes to the endosome where it binds dsRNA, suggesting its role to detect viral dsRNA. Toll-9 also induces apoptosis during DCV infection, contributing to its antiviral role. Together, this work identifies the role of Toll-9 in antiviral immunity against DCV infection through its ability to bind dsRNA and induce AKT-mediated RNAi antiviral immunity. IMPORTANCE Insects rely on innate immunity and RNA interference (RNAi) to combat viral infections. Our study underscores the pivotal role of Drosophila Toll-9 in antiviral immunity, aligning with findings in Bombyx mori , where Toll-9 activation upregulates the RNAi component Dicer2 . We demonstrate that Drosophila Toll-9 functions as a pattern recognition receptor (PRR) for double-stranded RNA (dsRNA) during Drosophila C virus (DCV) infection, akin to mammalian TLRs. Toll-9 activation leads to the upregulation of key RNAi components, Dicer2 and Argonaute2 , and dephosphorylation of AKT triggers apoptosis via induction of proapoptotic genes Hid and Reaper . This study also reveals that Toll-9 localizes in endosomal compartments where it interacts with dsRNA. These insights enhance our understanding of Drosophila innate immune mechanisms, reflecting the evolutionary conservation of immune responses across diverse species and providing impetus for further research into the conserved roles of TLRs across the animal kingdom.
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2
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Shamjana U, Vasu DA, Hembrom PS, Nayak K, Grace T. The role of insect gut microbiota in host fitness, detoxification and nutrient supplementation. Antonie Van Leeuwenhoek 2024; 117:71. [PMID: 38668783 DOI: 10.1007/s10482-024-01970-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Accepted: 04/15/2024] [Indexed: 05/01/2024]
Abstract
Insects are incredibly diverse, ubiquitous and have successfully flourished out of the dynamic and often unpredictable nature of evolutionary processes. The resident microbiome has accompanied the physical and biological adaptations that enable their continued survival and proliferation in a wide array of environments. The host insect and microbiome's bidirectional relationship exhibits their capability to influence each other's physiology, behavior and characteristics. Insects are reported to rely directly on the microbial community to break down complex food, adapt to nutrient-deficit environments, protect themselves from natural adversaries and control the expression of social behavior. High-throughput metagenomic approaches have enhanced the potential for determining the abundance, composition, diversity and functional activities of microbial fauna associated with insect hosts, enabling in-depth investigation into insect-microbe interactions. We undertook a review of some of the major advances in the field of metagenomics, focusing on insect-microbe interaction, diversity and composition of resident microbiota, the functional capability of endosymbionts and discussions on different symbiotic relationships. The review aims to be a valuable resource on insect gut symbiotic microbiota by providing a comprehensive understanding of how insect gut symbionts systematically perform a range of functions, viz., insecticide degradation, nutritional support and immune fitness. A thorough understanding of manipulating specific gut symbionts may aid in developing advanced insect-associated research to attain health and design strategies for pest management.
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Affiliation(s)
- U Shamjana
- Department of Genomic Science, School of Biological Sciences, Central University of Kerala, Kasaragod, Kerala, 671316, India
| | - Deepa Azhchath Vasu
- Department of Genomic Science, School of Biological Sciences, Central University of Kerala, Kasaragod, Kerala, 671316, India
| | - Preety Sweta Hembrom
- Department of Genomic Science, School of Biological Sciences, Central University of Kerala, Kasaragod, Kerala, 671316, India
| | - Karunakar Nayak
- Department of Genomic Science, School of Biological Sciences, Central University of Kerala, Kasaragod, Kerala, 671316, India
| | - Tony Grace
- Department of Genomic Science, School of Biological Sciences, Central University of Kerala, Kasaragod, Kerala, 671316, India.
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3
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Mpamhanga CD, Kounatidis I. The utility of Drosophila melanogaster as a fungal infection model. Front Immunol 2024; 15:1349027. [PMID: 38550600 PMCID: PMC10973011 DOI: 10.3389/fimmu.2024.1349027] [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: 12/04/2023] [Accepted: 02/27/2024] [Indexed: 04/02/2024] Open
Abstract
Invasive fungal diseases have profound effects upon human health and are on increase globally. The World Health Organization (WHO) in 2022 published the fungal priority list calling for improved public health interventions and advance research. Drosophila melanogaster presents an excellent model system to dissect host-pathogen interactions and has been proved valuable to study immunopathogenesis of fungal diseases. In this review we highlight the recent advances in fungal-Drosophila interplay with an emphasis on the recently published WHO's fungal priority list and we focus on available tools and technologies.
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Affiliation(s)
- Chengetai D Mpamhanga
- School of Life Health and Chemical Sciences, The Open University, Milton Keynes, United Kingdom
| | - Ilias Kounatidis
- School of Life Health and Chemical Sciences, The Open University, Milton Keynes, United Kingdom
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4
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Cabrera K, Hoard DS, Gibson O, Martinez DI, Wunderlich Z. Drosophila immune priming to Enterococcus faecalis relies on immune tolerance rather than resistance. PLoS Pathog 2023; 19:e1011567. [PMID: 37566589 PMCID: PMC10446173 DOI: 10.1371/journal.ppat.1011567] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2022] [Revised: 08/23/2023] [Accepted: 07/19/2023] [Indexed: 08/13/2023] Open
Abstract
Innate immune priming increases an organism's survival of a second infection after an initial, non-lethal infection. We used Drosophila melanogaster and an insect-derived strain of Enterococcus faecalis to study transcriptional control of priming. In contrast to other pathogens, the enhanced survival in primed animals does not correlate with decreased E. faecalis load. Further analysis shows that primed organisms tolerate, rather than resist infection. Using RNA-seq of immune tissues, we found many genes were upregulated in only primed flies, suggesting a distinct transcriptional program in response to initial and secondary infections. In contrast, few genes continuously express throughout the experiment or more efficiently re-activate upon reinfection. Priming experiments in immune deficient mutants revealed Imd is largely dispensable for responding to a single infection but needed to fully prime. Together, this indicates the fly's innate immune response is plastic-differing in immune strategy, transcriptional program, and pathway use depending on infection history.
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Affiliation(s)
- Kevin Cabrera
- Department of Developmental and Cell Biology, University of California, Irvine, California, United States of America
- Biological Design Center, Boston University, Boston, Massachusetts, United States of America
| | - Duncan S. Hoard
- Department of Developmental and Cell Biology, University of California, Irvine, California, United States of America
| | - Olivia Gibson
- Department of Biology, Boston University, Boston, Massachusetts, United States of America
| | - Daniel I. Martinez
- Department of Developmental and Cell Biology, University of California, Irvine, California, United States of America
| | - Zeba Wunderlich
- Biological Design Center, Boston University, Boston, Massachusetts, United States of America
- Department of Biology, Boston University, Boston, Massachusetts, United States of America
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5
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Hanson MA, Grollmus L, Lemaitre B. Ecology-relevant bacteria drive the evolution of host antimicrobial peptides in Drosophila. Science 2023; 381:eadg5725. [PMID: 37471548 DOI: 10.1126/science.adg5725] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2023] [Accepted: 06/08/2023] [Indexed: 07/22/2023]
Abstract
Antimicrobial peptides are host-encoded immune effectors that combat pathogens and shape the microbiome in plants and animals. However, little is known about how the host antimicrobial peptide repertoire is adapted to its microbiome. Here, we characterized the function and evolution of the Diptericin antimicrobial peptide family of Diptera. Using mutations affecting the two Diptericins (Dpt) of Drosophila melanogaster, we reveal the specific role of DptA for the pathogen Providencia rettgeri and DptB for the gut mutualist Acetobacter. The presence of DptA- or DptB-like genes across Diptera correlates with the presence of Providencia and Acetobacter in their environment. Moreover, DptA- and DptB-like sequences predict host resistance against infection by these bacteria across the genus Drosophila. Our study explains the evolutionary logic behind the bursts of rapid evolution of an antimicrobial peptide family and reveals how the host immune repertoire adapts to changing microbial environments.
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Affiliation(s)
- M A Hanson
- Global Health Institute, School of Life Science, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
- Disease Ecology and Evolution, Biosciences, University of Exeter, Penryn, United Kingdom
| | - L Grollmus
- Global Health Institute, School of Life Science, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - B Lemaitre
- Global Health Institute, School of Life Science, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
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6
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Huang J, Lou Y, Liu J, Bulet P, Cai C, Ma K, Jiao R, Hoffmann JA, Liégeois S, Li Z, Ferrandon D. A Toll pathway effector protects Drosophila specifically from distinct toxins secreted by a fungus or a bacterium. Proc Natl Acad Sci U S A 2023; 120:e2205140120. [PMID: 36917667 PMCID: PMC10041126 DOI: 10.1073/pnas.2205140120] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2022] [Accepted: 01/09/2023] [Indexed: 03/16/2023] Open
Abstract
The Drosophila systemic immune response against many Gram-positive bacteria and fungi is mediated by the Toll pathway. How Toll-regulated effectors actually fulfill this role remains poorly understood as the known Toll-regulated antimicrobial peptide (AMP) genes are active only against filamentous fungi and not against Gram-positive bacteria or yeasts. Besides AMPs, two families of peptides secreted in response to infectious stimuli that activate the Toll pathway have been identified, namely Bomanins and peptides derived from a polyprotein precursor known as Baramicin A (BaraA). Unexpectedly, the deletion of a cluster of 10 Bomanins phenocopies the Toll mutant phenotype of susceptibility to infections. Here, we demonstrate that BaraA is required specifically in the host defense against Enterococcus faecalis and against the entomopathogenic fungus Metarhizium robertsii, albeit the fungal burden is not altered in BaraA mutants. BaraA protects the fly from the action of distinct toxins secreted by these Gram-positive and fungal pathogens, respectively, Enterocin V and Destruxin A. The injection of Destruxin A leads to the rapid paralysis of flies, whether wild type (WT) or mutant. However, a larger fraction of wild-type than BaraA flies recovers from paralysis within 5 to 10 h. BaraAs' function in protecting the host from the deleterious action of Destruxin is required in glial cells, highlighting a resilience role for the Toll pathway in the nervous system against microbial virulence factors. Thus, in complement to the current paradigm, innate immunity can cope effectively with the effects of toxins secreted by pathogens through the secretion of dedicated peptides, independently of xenobiotics detoxification pathways.
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Affiliation(s)
- Jianqiong Huang
- Sino-French Hoffmann Institute, Guangzhou Medical University, Guangzhou511436, China
| | - Yanyan Lou
- Sino-French Hoffmann Institute, Guangzhou Medical University, Guangzhou511436, China
| | - Jiyong Liu
- Sino-French Hoffmann Institute, Guangzhou Medical University, Guangzhou511436, China
| | - Philippe Bulet
- Université Grenoble Alpes, Institute for Advanced Biosciences, INSERM U1209, CNRS, UMR 5309, 38000Grenoble, France
- Platform BioPark Archamps, 74160Archamps, France
| | - Chuping Cai
- Sino-French Hoffmann Institute, Guangzhou Medical University, Guangzhou511436, China
- Université de Strasbourg, Faculté des Sciences de la Vie, 67000Strasbourg, France
- Modèles Insectes d'Immunité Innée, Unité Propre de Recherche 9022 du CNRS, Institut de Biologie Moléculaire et Cellulaire du CNRS, 67084Strasbourg, France
| | - Kaiyu Ma
- Sino-French Hoffmann Institute, Guangzhou Medical University, Guangzhou511436, China
| | - Renjie Jiao
- Sino-French Hoffmann Institute, Guangzhou Medical University, Guangzhou511436, China
| | - Jules A. Hoffmann
- Sino-French Hoffmann Institute, Guangzhou Medical University, Guangzhou511436, China
- Université de Strasbourg, Faculté des Sciences de la Vie, 67000Strasbourg, France
- Modèles Insectes d'Immunité Innée, Unité Propre de Recherche 9022 du CNRS, Institut de Biologie Moléculaire et Cellulaire du CNRS, 67084Strasbourg, France
- Université de Strasbourg Institute for Advanced Study, 67000Strasbourg, France
| | - Samuel Liégeois
- Sino-French Hoffmann Institute, Guangzhou Medical University, Guangzhou511436, China
- Université de Strasbourg, Faculté des Sciences de la Vie, 67000Strasbourg, France
- Modèles Insectes d'Immunité Innée, Unité Propre de Recherche 9022 du CNRS, Institut de Biologie Moléculaire et Cellulaire du CNRS, 67084Strasbourg, France
| | - Zi Li
- Sino-French Hoffmann Institute, Guangzhou Medical University, Guangzhou511436, China
| | - Dominique Ferrandon
- Sino-French Hoffmann Institute, Guangzhou Medical University, Guangzhou511436, China
- Université de Strasbourg, Faculté des Sciences de la Vie, 67000Strasbourg, France
- Modèles Insectes d'Immunité Innée, Unité Propre de Recherche 9022 du CNRS, Institut de Biologie Moléculaire et Cellulaire du CNRS, 67084Strasbourg, France
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7
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Unraveling the Role of Antimicrobial Peptides in Insects. Int J Mol Sci 2023; 24:ijms24065753. [PMID: 36982826 PMCID: PMC10059942 DOI: 10.3390/ijms24065753] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Revised: 03/14/2023] [Accepted: 03/15/2023] [Indexed: 03/19/2023] Open
Abstract
Antimicrobial peptides (AMPs) are short, mainly positively charged, amphipathic molecules. AMPs are important effectors of the immune response in insects with a broad spectrum of antibacterial, antifungal, and antiparasitic activity. In addition to these well-known roles, AMPs exhibit many other, often unobvious, functions in the host. They support insects in the elimination of viral infections. AMPs participate in the regulation of brain-controlled processes, e.g., sleep and non-associative learning. By influencing neuronal health, communication, and activity, they can affect the functioning of the insect nervous system. Expansion of the AMP repertoire and loss of their specificity is connected with the aging process and lifespan of insects. Moreover, AMPs take part in maintaining gut homeostasis, regulating the number of endosymbionts as well as reducing the number of foreign microbiota. In turn, the presence of AMPs in insect venom prevents the spread of infection in social insects, where the prey may be a source of pathogens.
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8
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Qiu JF, Cui WZ, Zhang Q, Dai TM, Liu K, Li JL, Wang YJ, Sima YH, Xu SQ. Temporal transcriptome reveals that circadian clock is involved in the dynamic regulation of immune response to bacterial infection in Bombyx mori. INSECT SCIENCE 2023; 30:31-46. [PMID: 35446483 DOI: 10.1111/1744-7917.13043] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Revised: 03/11/2022] [Accepted: 03/23/2022] [Indexed: 06/14/2023]
Abstract
The circadian clock plays a critical role in the regulation of host immune defense. However, the mechanistic basis for this regulation is largely unknown. Herein, the core clock gene cryptochrome1 (cry1) knockout line in Bombyx mori, an invertebrate animal model, was constructed to obtain the silkworm with dysfunctional molecular clock, and the dynamic regulation of the circadian clock on the immune responsiveness within 24 h of Staphylococcus aureus infection was analyzed. We found that deletion of cry1 decreased viability of silkworms and significantly reduced resistance of larvae to S. aureus. Time series RNA-seq analysis identified thousands of rhythmically expressed genes, including immune response genes, in the larval immune tissue, fat bodies. Uninfected cry1 knockout silkworms exhibited expression patterns of rhythmically expressed genes similar to wild-type (WT) silkworms infected with S. aureus. However, cry1 knockout silkworms exhibited a seriously weakened response to S. aureus infection. The immune response peaked at 6 and 24 h after infection, during which "transcription storms" occurred, and the expression levels of the immune response genes, PGRP and antimicrobial peptides (AMPs), were significantly upregulated in WT. In contrast, cry1 knockout did not effectively activate Toll, Imd, or NF-κB signaling pathways during the immune adjustment period from 12 to 18 h after infection, resulting in failure to initiate the immune responsiveness peak at 24 h after infection. This may be related to inhibited silkworm fat body energy metabolism. These results demonstrated the dynamic regulation of circadian clock on silkworm immune response to bacterial infection and provided important insights into host antimicrobial defense mechanisms.
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Affiliation(s)
- Jian-Feng Qiu
- School of Biology and Basic Medical Sciences, Suzhou Medical College, Soochow University, Suzhou, China, Jiangsu Province
- Institute of Agricultural Biotechnology & Ecology (IABE), Soochow University, Suzhou, China, Jiangsu Province
| | - Wen-Zhao Cui
- School of Biology and Basic Medical Sciences, Suzhou Medical College, Soochow University, Suzhou, China, Jiangsu Province
- Institute of Agricultural Biotechnology & Ecology (IABE), Soochow University, Suzhou, China, Jiangsu Province
| | - Qiang Zhang
- School of Biology and Basic Medical Sciences, Suzhou Medical College, Soochow University, Suzhou, China, Jiangsu Province
- Institute of Agricultural Biotechnology & Ecology (IABE), Soochow University, Suzhou, China, Jiangsu Province
| | - Tai-Ming Dai
- School of Biology and Basic Medical Sciences, Suzhou Medical College, Soochow University, Suzhou, China, Jiangsu Province
- Institute of Agricultural Biotechnology & Ecology (IABE), Soochow University, Suzhou, China, Jiangsu Province
| | - Kai Liu
- School of Biology and Basic Medical Sciences, Suzhou Medical College, Soochow University, Suzhou, China, Jiangsu Province
- Institute of Agricultural Biotechnology & Ecology (IABE), Soochow University, Suzhou, China, Jiangsu Province
| | - Jiang-Lan Li
- School of Biology and Basic Medical Sciences, Suzhou Medical College, Soochow University, Suzhou, China, Jiangsu Province
- Institute of Agricultural Biotechnology & Ecology (IABE), Soochow University, Suzhou, China, Jiangsu Province
| | - Yu-Jun Wang
- Guangxi Key Laboratory of Beibu Gulf Marine Biodiversity Conservation, College of Marine Sciences, Beibu Gulf University, Qinzhou, China, Guangxi Province
| | - Yang-Hu Sima
- School of Biology and Basic Medical Sciences, Suzhou Medical College, Soochow University, Suzhou, China, Jiangsu Province
- Institute of Agricultural Biotechnology & Ecology (IABE), Soochow University, Suzhou, China, Jiangsu Province
| | - Shi-Qing Xu
- School of Biology and Basic Medical Sciences, Suzhou Medical College, Soochow University, Suzhou, China, Jiangsu Province
- Institute of Agricultural Biotechnology & Ecology (IABE), Soochow University, Suzhou, China, Jiangsu Province
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9
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Sakakibara Y, Yamashiro R, Chikamatsu S, Hirota Y, Tsubokawa Y, Nishijima R, Takei K, Sekiya M, Iijima KM. Drosophila Toll-9 is induced by aging and neurodegeneration to modulate stress signaling and its deficiency exacerbates tau-mediated neurodegeneration. iScience 2023; 26:105968. [PMID: 36718365 PMCID: PMC9883205 DOI: 10.1016/j.isci.2023.105968] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2022] [Revised: 12/06/2022] [Accepted: 01/10/2023] [Indexed: 01/15/2023] Open
Abstract
Drosophila Toll-9 is most closely related to mammalian Toll-like receptors; however, physiological functions of Toll-9 remain elusive. We examined the roles of Toll-9 in fly brains in aging and neurodegeneration. Toll-9 mRNA levels were increased in aged fly heads accompanied by activation of nuclear factor-kappa B (NF-kB) and stress-activated protein kinase (SAPK) signaling, and many of these changes were modulated by Toll-9 in glial cells. The loss of Toll-9 did not affect lifespan or brain integrity, whereas it exacerbated hydrogen peroxide-induced lethality. Toll-9 expression was also induced by nerve injury but did not affect acute stress response or glial engulfment activity, suggesting Toll-9 may modulate subsequent neurodegeneration. In a fly tauopathy model, Toll-9 deficiency enhanced neurodegeneration and disease-related tau phosphorylation with reduced SAPK activity, and blocking SAPK enhanced tau phosphorylation and neurodegeneration. In sum, Toll-9 is induced upon aging and nerve injury and affects neurodegeneration by modulating stress kinase signaling.
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Affiliation(s)
- Yasufumi Sakakibara
- Department of Neurogenetics, Center for Development of Advanced Medicine for Dementia, National Center for Geriatrics and Gerontology, Obu, Aichi 474-8511, Japan
| | - Risa Yamashiro
- Department of Experimental Gerontology, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya 467-8603, Japan
| | - Sachie Chikamatsu
- Department of Neurogenetics, Center for Development of Advanced Medicine for Dementia, National Center for Geriatrics and Gerontology, Obu, Aichi 474-8511, Japan,Department of Experimental Gerontology, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya 467-8603, Japan
| | - Yu Hirota
- Department of Neurogenetics, Center for Development of Advanced Medicine for Dementia, National Center for Geriatrics and Gerontology, Obu, Aichi 474-8511, Japan,Reseach Fellow of Japan Society for the Promotion of Science, Tokyo, Japan
| | - Yoko Tsubokawa
- Department of Neurogenetics, Center for Development of Advanced Medicine for Dementia, National Center for Geriatrics and Gerontology, Obu, Aichi 474-8511, Japan
| | - Risa Nishijima
- Department of Neurogenetics, Center for Development of Advanced Medicine for Dementia, National Center for Geriatrics and Gerontology, Obu, Aichi 474-8511, Japan
| | - Kimi Takei
- Department of Neurogenetics, Center for Development of Advanced Medicine for Dementia, National Center for Geriatrics and Gerontology, Obu, Aichi 474-8511, Japan
| | - Michiko Sekiya
- Department of Neurogenetics, Center for Development of Advanced Medicine for Dementia, National Center for Geriatrics and Gerontology, Obu, Aichi 474-8511, Japan,Department of Experimental Gerontology, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya 467-8603, Japan,Corresponding author
| | - Koichi M. Iijima
- Department of Neurogenetics, Center for Development of Advanced Medicine for Dementia, National Center for Geriatrics and Gerontology, Obu, Aichi 474-8511, Japan,Department of Experimental Gerontology, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya 467-8603, Japan,Corresponding author
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10
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Xu R, Lou Y, Tidu A, Bulet P, Heinekamp T, Martin F, Brakhage A, Li Z, Liégeois S, Ferrandon D. The Toll pathway mediates Drosophila resilience to Aspergillus mycotoxins through specific Bomanins. EMBO Rep 2023; 24:e56036. [PMID: 36322050 PMCID: PMC9827548 DOI: 10.15252/embr.202256036] [Citation(s) in RCA: 3] [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: 08/26/2022] [Revised: 10/06/2022] [Accepted: 10/14/2022] [Indexed: 12/28/2022] Open
Abstract
Host defense against infections encompasses both resistance, which targets microorganisms for neutralization or elimination, and resilience/disease tolerance, which allows the host to withstand/tolerate pathogens and repair damages. In Drosophila, the Toll signaling pathway is thought to mediate resistance against fungal infections by regulating the secretion of antimicrobial peptides, potentially including Bomanins. We find that Aspergillus fumigatus kills Drosophila Toll pathway mutants without invasion because its dissemination is blocked by melanization, suggesting a role for Toll in host defense distinct from resistance. We report that mutants affecting the Toll pathway or the 55C Bomanin locus are susceptible to the injection of two Aspergillus mycotoxins, restrictocin and verruculogen. The vulnerability of 55C deletion mutants to these mycotoxins is rescued by the overexpression of Bomanins specific to each challenge. Mechanistically, flies in which BomS6 is expressed in the nervous system exhibit an enhanced recovery from the tremors induced by injected verruculogen and display improved survival. Thus, innate immunity also protects the host against the action of microbial toxins through secreted peptides and thereby increases its resilience to infection.
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Affiliation(s)
- Rui Xu
- Sino‐French Hoffmann InstituteGuangzhou Medical UniversityGuangzhouChina
- Université de StrasbourgStrasbourgFrance
- Modèles Insectes de l'Immunité InnéeUPR 9022 du CNRSStrasbourgFrance
| | - Yanyan Lou
- Sino‐French Hoffmann InstituteGuangzhou Medical UniversityGuangzhouChina
- Université de StrasbourgStrasbourgFrance
- Modèles Insectes de l'Immunité InnéeUPR 9022 du CNRSStrasbourgFrance
| | - Antonin Tidu
- Université de StrasbourgStrasbourgFrance
- Architecture et Réactivité de l'ARNUPR 9002 du CNRSStrasbourgFrance
| | - Philippe Bulet
- CR Université Grenoble Alpes, Institute for Advanced Biosciences, Inserm U1209CNRS UMR 5309GrenobleFrance
- Platform BioPark ArchampsArchampsFrance
| | - Thorsten Heinekamp
- Department of Molecular and Applied MicrobiologyLeibniz Institute for Natural Product Research and Infection Biology ‐ Hans Knöll Institute (Leibniz‐HKI)JenaGermany
| | - Franck Martin
- Université de StrasbourgStrasbourgFrance
- Architecture et Réactivité de l'ARNUPR 9002 du CNRSStrasbourgFrance
| | - Axel Brakhage
- Department of Molecular and Applied MicrobiologyLeibniz Institute for Natural Product Research and Infection Biology ‐ Hans Knöll Institute (Leibniz‐HKI)JenaGermany
- Institute of MicrobiologyFriedrich Schiller University JenaJenaGermany
| | - Zi Li
- Sino‐French Hoffmann InstituteGuangzhou Medical UniversityGuangzhouChina
| | - Samuel Liégeois
- Sino‐French Hoffmann InstituteGuangzhou Medical UniversityGuangzhouChina
- Université de StrasbourgStrasbourgFrance
- Modèles Insectes de l'Immunité InnéeUPR 9022 du CNRSStrasbourgFrance
| | - Dominique Ferrandon
- Sino‐French Hoffmann InstituteGuangzhou Medical UniversityGuangzhouChina
- Université de StrasbourgStrasbourgFrance
- Modèles Insectes de l'Immunité InnéeUPR 9022 du CNRSStrasbourgFrance
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11
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Vaibhvi V, Künzel S, Roeder T. Hemocytes and fat body cells, the only professional immune cell types in Drosophila, show strikingly different responses to systemic infections. Front Immunol 2022; 13:1040510. [PMID: 36505446 PMCID: PMC9726733 DOI: 10.3389/fimmu.2022.1040510] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2022] [Accepted: 11/07/2022] [Indexed: 11/24/2022] Open
Abstract
The fruit fly Drosophila is an excellent model to study the response of different immunocompetent organs during systemic infection. In the present study, we intended to test the hypothesis that the only professional immune organs of the fly, the fat body and hemocytes, show substantial similarities in their responses to systemic infection. However, comprehensive transcriptome analysis of isolated organs revealed highly divergent transcript signatures, with the few commonly regulated genes encoding mainly classical immune effectors from the antimicrobial peptide family. The fat body and the hemocytes each have specific reactions that are not present in the other organ. Fat body-specific responses comprised those enabling an improved peptide synthesis and export. This reaction is accompanied by transcriptomic shifts enabling the use of the energy resources of the fat body more efficiently. Hemocytes, on the other hand, showed enhanced signatures related to phagocytosis. Comparing immune-induced signatures of both cell types with those of whole-body responses showed only a minimal correspondence, mostly restricted again to antimicrobial peptide genes. In summary, the two major immunocompetent cell types of Drosophila show highly specific responses to infection, which are closely linked to the primary function of the respective organ in the landscape of the systemic immune response.
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Affiliation(s)
- Vaibhvi Vaibhvi
- Department of Molecular Physiology, Zoology Institute, Kiel University, Kiel, Germany
| | - Sven Künzel
- Department of Evolutionary Genetics, Max Planck Institute for Evolutionary Biology, Plön, Germany
| | - Thomas Roeder
- Department of Molecular Physiology, Zoology Institute, Kiel University, Kiel, Germany,German Center for Lung Research, Airway Research Center North, Kiel, Germany,*Correspondence: Thomas Roeder,
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12
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Nishide Y, Nagamine K, Kageyama D, Moriyama M, Futahashi R, Fukatsu T. A new antimicrobial peptide, Pentatomicin, from the stinkbug Plautia stali. Sci Rep 2022; 12:16503. [PMID: 36192417 PMCID: PMC9529961 DOI: 10.1038/s41598-022-20427-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Accepted: 09/13/2022] [Indexed: 12/29/2022] Open
Abstract
Antimicrobial peptides (AMPs) play crucial roles in the innate immunity of diverse organisms, which exhibit remarkable diversity in size, structural property and antimicrobial spectrum. Here, we describe a new AMP, named Pentatomicin, from the stinkbug Plautia stali (Hemiptera: Pentatomidae). Orthologous nucleotide sequences of Pentatomicin were present in stinkbugs and beetles but not in other insect groups. Notably, orthologous sequences were also detected from a horseshoe crab, cyanobacteria and proteobacteria, suggesting the possibility of inter-domain horizontal gene transfers of Pentatomicin and allied protein genes. The recombinant protein of Pentatomicin was effective against an array of Gram-positive bacteria but not against Gram-negative bacteria. Upon septic shock, the expression of Pentatomicin drastically increased in a manner similar to other AMPs. On the other hand, unlike other AMPs, mock and saline injections increased the expression of Pentatomicin. RNAi-mediated downregulation of Imd pathway genes (Imd and Relish) and Toll pathway genes (MyD88 and Dorsal) revealed that the expression of Pentatomicin is under the control of Toll pathway. Being consistent with in vitro effectiveness of the recombinant protein, adult insects injected with dsRNA of Pentatomicin exhibited higher vulnerability to Gram-positive Staphylococcus aureus than to Gram-negative Escherichia coli. We discovered high levels of Pentatomicin expression in eggs, which is atypical of other AMPs and suggestive of its biological functioning in eggs. Contrary to the expectation, however, RNAi-mediated downregulation of Pentatomicin did not affect normal embryonic development of P. stali. Moreover, the downregulation of Pentatomicin in eggs did not affect vertical symbiont transmission to the offspring even under heavily contaminated conditions, which refuted our expectation that the antimicrobial activity of Pentatomicin may contribute to egg surface-mediated symbiont transmission by suppressing microbial contaminants.
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Affiliation(s)
- Yudai Nishide
- Institute of Agrobiological Sciences Ohwashi, National Agriculture and Food Research Organization (NARO), Tsukuba, 305-8634, Japan.
| | - Keisuke Nagamine
- Institute of Agrobiological Sciences Ohwashi, National Agriculture and Food Research Organization (NARO), Tsukuba, 305-8634, Japan
- Japan Society for the Promotion of Science (JSPS), Tokyo, 102-0083, Japan
| | - Daisuke Kageyama
- Institute of Agrobiological Sciences Ohwashi, National Agriculture and Food Research Organization (NARO), Tsukuba, 305-8634, Japan
| | - Minoru Moriyama
- National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, 305-8566, Japan
| | - Ryo Futahashi
- National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, 305-8566, Japan.
| | - Takema Fukatsu
- National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, 305-8566, Japan.
- Department of Biological Sciences, Graduate School of Science, University of Tokyo, Tokyo, 113-0033, Japan.
- Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, 305-8572, Japan.
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Lipopolysaccharide -mediated resistance to host antimicrobial peptides and hemocyte-derived reactive-oxygen species are the major Providencia alcalifaciens virulence factors in Drosophila melanogaster. PLoS Pathog 2022; 18:e1010825. [PMID: 36084158 PMCID: PMC9491580 DOI: 10.1371/journal.ppat.1010825] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Revised: 09/21/2022] [Accepted: 08/23/2022] [Indexed: 02/07/2023] Open
Abstract
Bacteria from the genus Providencia are ubiquitous Gram-negative opportunistic pathogens, causing “travelers’ diarrhea”, urinary tract, and other nosocomial infections in humans. Some Providencia strains have also been isolated as natural pathogens of Drosophila melanogaster. Despite clinical relevance and extensive use in Drosophila immunity research, little is known about Providencia virulence mechanisms and the corresponding insect host defenses. To close this knowledge gap, we investigated the virulence factors of a representative Providencia species—P. alcalifaciens which is highly virulent to fruit flies and amenable to genetic manipulations. We generated a P. alcalifaciens transposon mutant library and performed an unbiased forward genetics screen in vivo for attenuated mutants. Our screen uncovered 23 mutants with reduced virulence. The vast majority of them had disrupted genes linked to lipopolysaccharide (LPS) synthesis or modifications. These LPS mutants were sensitive to cationic antimicrobial peptides (AMPs) in vitro and their virulence was restored in Drosophila mutants lacking most AMPs. Thus, LPS-mediated resistance to host AMPs is one of the virulence strategies of P. alcalifaciens. Another subset of P. alcalifaciens attenuated mutants exhibited increased susceptibility to reactive oxygen species (ROS) in vitro and their virulence was rescued by chemical scavenging of ROS in flies prior to infection. Using genetic analysis, we found that the enzyme Duox specifically in hemocytes is the source of bactericidal ROS targeting P. alcalifaciens. Consistently, the virulence of ROS-sensitive P. alcalifaciens mutants was rescued in flies with Duox knockdown in hemocytes. Therefore, these genes function as virulence factors by helping bacteria to counteract the ROS immune response. Our reciprocal analysis of host-pathogen interactions between D. melanogaster and P. alcalifaciens identified that AMPs and hemocyte-derived ROS are the major defense mechanisms against P. alcalifaciens, while the ability of the pathogen to resist these host immune responses is its major virulence mechanism. Thus, our work revealed a host-pathogen conflict mediated by ROS and AMPs. Pathogens express special molecules or structures called virulence factors to successfully infect a host. By identifying these factors, we can learn how hosts fight and how pathogens cause infections. Here, we identified virulence factors of the human and fruit fly pathogen Providencia alcalifaciens, by infecting flies with a series of mutants of this pathogen. In this way, we detected 23 mutants that were less virulent. Some of these less virulent mutants were hypersensitive to fruit fly immune defense molecules called antimicrobial peptides (AMPs), while others were sensitive to reactive oxygen species (ROS) produced by the immune cells. Notably, AMPs-sensitive mutants remained virulent in a Drosophila mutant that lacks AMPs, while pathogens sensitive to oxidative stress retained their virulence in a fruit fly mutant devoid of oxidative species. These results suggest that the ability of P. alcalifaciens to resist two major host immune molecules, namely AMPs and ROS, is the major virulence mechanism. Overall, our systematic analysis of P. alcalifaciens virulence factors has identified the major defense mechanisms of the fruit fly against this pathogen and the bacterial mechanisms to combat these immune responses.
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Hanson MA, Kondo S, Lemaitre B. Drosophila immunity: the Drosocin gene encodes two host defence peptides with pathogen-specific roles. Proc Biol Sci 2022; 289:20220773. [PMID: 35730150 PMCID: PMC9233930 DOI: 10.1098/rspb.2022.0773] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Antimicrobial peptides (AMPs) are key to defence against infection in plants and animals. Use of AMP mutations in Drosophila has now revealed that AMPs can additively or synergistically contribute to defence in vivo. However, these studies also revealed high specificity, wherein just one AMP contributes an outsized role in combatting a specific pathogen. Here, we show the Drosocin locus (CG10816) is more complex than previously described. In addition to its namesake peptide 'Drosocin', it encodes a second mature peptide from a precursor via furin cleavage. This peptide corresponds to the previously uncharacterized 'Immune-induced Molecule 7'. A polymorphism (Thr52Ala) in the Drosocin precursor protein previously masked the identification of this peptide, which we name 'Buletin'. Using mutations differently affecting Drosocin and Buletin, we show that only Drosocin contributes to Drosocin gene-mediated defence against Enterobacter cloacae. Strikingly, we observed that Buletin, but not Drosocin, contributes to the Drosocin gene-mediated defence against Providencia burhodogranariea, including an importance of the Thr52Ala polymorphism for survival. Our study reveals that the Drosocin gene encodes two prominent host defence peptides with different specificity against distinct pathogens. This finding emphasizes the complexity of the Drosophila humoral response and demonstrates how natural polymorphisms can affect host susceptibility.
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Affiliation(s)
- M. A. Hanson
- Global Health Institute, School of Life Science, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - S. Kondo
- Invertebrate Genetics Laboratory, Genetic Strains Research Center, National Institute of Genetics, Mishima, Japan
| | - B. Lemaitre
- Global Health Institute, School of Life Science, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
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15
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Larval exposure to parasitic Varroa destructor mites triggers specific immune responses in different honey bee castes and species. Mol Cell Proteomics 2022; 21:100257. [PMID: 35710070 PMCID: PMC9418504 DOI: 10.1016/j.mcpro.2022.100257] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2022] [Revised: 06/03/2022] [Accepted: 06/09/2022] [Indexed: 12/03/2022] Open
Abstract
Innate immune systems are key defenses of animals and particularly important in species that lack the sophisticated adaptive immune systems as found in vertebrates. Here, we were interested to quantify variation in innate immune responses of insects in hosts that differ in their parasite susceptibility. To do this, we studied immune responses in honey bees, which can host a remarkable number of different parasites, which are major contributors of declining bee health and colony losses. The most significant parasite of honey bees is the mite Varroa destructor, which has infested the majority of global honey bee populations, and its control remains a major challenge for beekeepers. However, a number of nonmanaged honey bees seem able to control Varroa infections, for example, the Eastern honey bee Apis ceranacerana or the African honey bee Apis mellifera scutellata. These bees therefore make interesting study subjects to identify underlaying resistance traits, for example, by comparing them to more susceptible bee genotypes such as Western honey bees (A. melliferaligustica). We conducted a series of interlinked experiments and started with behavioral assays to compare the attractiveness of bee larvae to mites using different honey bee genotypes and castes. We found that 6-day-old larvae are always most attractive to mites, independently of genotype or castes. In a next step, we compared volatile profiles of the most attractive larvae to test whether they could be used by mites for host selection. We found that the abundance of volatile compounds differed between larval ages, but we also found significant differences between genotypes and castes. To further study the expected underlaying physiological differences between potentially resistant and susceptible host larvae, we compared the larval hemolymph proteomes of the three honey bee genotypes and two castes in response to mite exposure. We identified consistent upregulation of immune and stress-related genes in Varroa-exposed larvae, which differed between genotypes and castes. Tolerant honey bee castes and genotypes were characterized by stronger or more distinct immune esponses. In summary, we provide first insights into the complex involvement of the innate immune system of tolerant honey bees against mite infestations, which could be used for future breeding purposes. Honey bee larvae are most susceptible to mite infestations shortly before brood cell capping. Larval attractiveness to mites is independent of bee caste or genotype. Volatile compound abundance differed between genotypes, castes, and larval ages. Mite exposure induces specific immune and stress responses in different genotypes and castes.
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16
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Turner M, Pietri JE. Antimicrobial peptide expression in the cockroach gut during enterobacterial infection is specific and influenced by type III secretion. Biol Open 2022; 11:275513. [PMID: 35611712 PMCID: PMC9167622 DOI: 10.1242/bio.059414] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Accepted: 04/28/2022] [Indexed: 12/29/2022] Open
Abstract
Omnivorous synanthropic cockroaches, such as the German cockroach (Blattella germanica), are reservoirs and vectors of enteric bacterial pathogens. A lifestyle conducive to frequent encounters with high loads of diverse bacteria may have led to the evolution of unique innate immune systems in these insects. The innate immune response of insects relies largely on generalized mechanisms to sense and eliminate foreign microbes. However, analyses of the genomes of common synanthropic cockroaches previously revealed a repertoire of pathogen associated molecular pattern (PAMP) receptors and antimicrobial peptides (AMPs) that is significantly expanded relative to most holometabolous insect models and vectors, supporting the intriguing possibility that cockroaches may encode enhanced recognition within their immune system and may possess an enhanced capacity to fine tune innate immune responses. Investigating how cockroaches respond to infection with enterobacteria provides the opportunity to expand our fundamental knowledge of the regulation of insect innate immunity in a context that is biologically and medically relevant. German cockroaches can harbor both Salmonella enterica serovar Typhimurium and Escherichia coli in their gut without experiencing pathogenesis. The former colonizes the gut and replicates while the latter persists only transiently. We hypothesized that differences in the innate immune response may contribute to or result from the difference in infection dynamics between the two enterobacteria. To test this hypothesis, we used qRT-PCR to analyze expression of five genes encoding representative AMPs (Attacins, Blattellicin, Defensins) in the gut of German cockroaches 1 and 24 h after ingestion of live or heat-killed enterobacteria. We found that robust AMP expression was induced in response to ingestion of a live wild-type strain of S. Typhimurium, but not in response to live E. coli, heat-killed S. Typhimurium, or a live mutant strain of S. Typhimurium lacking type III secretion systems. These results indicate that the cockroach immune system does not respond to stimulation with high levels of ingested bacterial PAMPs such as peptidoglycan. Rather, AMP expression in the gut appears to be induced by active bacterial colonization involving type III secretion. We speculate that this form of regulation may have evolved to prevent over activation of the immune system from frequent ingestion of innocuous, non-colonizing, or non-viable bacteria. While additional work is needed to delineate the molecular mechanisms underlying our observations, our findings provide significant novel insight into the immunological adaptation of cockroaches to life in septic environments as well as the factors that regulate bacterial pathogen transmission by these insects.
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17
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Sensing microbial infections in the Drosophila melanogaster genetic model organism. Immunogenetics 2022; 74:35-62. [DOI: 10.1007/s00251-021-01239-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2021] [Accepted: 11/20/2021] [Indexed: 12/17/2022]
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18
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Carboni AL, Hanson MA, Lindsay SA, Wasserman SA, Lemaitre B. Cecropins contribute to Drosophila host defense against a subset of fungal and Gram-negative bacterial infection. Genetics 2022; 220:iyab188. [PMID: 34791204 PMCID: PMC8733632 DOI: 10.1093/genetics/iyab188] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Accepted: 10/15/2021] [Indexed: 11/14/2022] Open
Abstract
Cecropins are small helical secreted peptides with antimicrobial activity that are widely distributed among insects. Genes encoding Cecropins are strongly induced upon infection, pointing to their role in host defense. In Drosophila, four cecropin genes clustered in the genome (CecA1, CecA2, CecB, and CecC) are expressed upon infection downstream of the Toll and Imd pathways. In this study, we generated a short deletion ΔCecA-C removing the whole cecropin locus. Using the ΔCecA-C deficiency alone or in combination with other antimicrobial peptide (AMP) mutations, we addressed the function of Cecropins in the systemic immune response. ΔCecA-C flies were viable and resisted challenge with various microbes as wild-type. However, removing ΔCecA-C in flies already lacking 10 other AMP genes revealed a role for Cecropins in defense against Gram-negative bacteria and fungi. Measurements of pathogen loads confirm that Cecropins contribute to the control of certain Gram-negative bacteria, notably Enterobacter cloacae and Providencia heimbachae. Collectively, our work provides the first genetic demonstration of a role for Cecropins in insect host defense and confirms their in vivo activity primarily against Gram-negative bacteria and fungi. Generation of a fly line (ΔAMP14) that lacks 14 immune inducible AMPs provides a powerful tool to address the function of these immune effectors in host-pathogen interactions and beyond.
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Affiliation(s)
- Alexia L Carboni
- Global Health Institute, School of Life Science, École Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Mark A Hanson
- Global Health Institute, School of Life Science, École Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Scott A Lindsay
- Division of Biological Sciences, University of California San Diego (UCSD), La Jolla, CA 92093, USA
| | - Steven A Wasserman
- Division of Biological Sciences, University of California San Diego (UCSD), La Jolla, CA 92093, USA
| | - Bruno Lemaitre
- Global Health Institute, School of Life Science, École Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
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Csonka K, Tasi Z, Vedelek V, Vágvölgyi C, Sinka R, Gácser A. Deciphering of Candida parapsilosis induced immune response in Drosophila melanogaster. Virulence 2021; 12:2571-2582. [PMID: 34569900 PMCID: PMC8477938 DOI: 10.1080/21505594.2021.1980989] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
Abstract
Candida infections are the most prevalent cause of serious human mycoses and are the third most common pathogens isolated from bloodstream infections in hospitalized patients. C. parapsilosis is a member of the non-albicans spp., which have a predilection for causing life-threatening disease in neonates and hospitalized pediatric patients. In this study, we utilized a Drosophila melanogaster infection model to analyze the immunological responses to C. parapsilosis. Our results demonstrate that the Toll pathway in Drosophila controls C. parapsilosis proliferation as the Toll signaling mutant MyD88-/- flies are highly susceptible to C. parapsilosis. We also confirmed that the MyD88-/- fly is a convenient invertebrate animal model to analyze virulence properties of different species and strains from the C. parapsilosis sensu lato complex as C. orthopsilosis, C. metapsilosis proved to be less virulent than C. parapsilosis sensu stricto and the N-mannan deficient C. parapsilosis och1Δ/Δ strain showed attenuated pathogenicity in this immunodeficient Drosophila background. We also found that Persephone protease is not required for detection and activation of Toll pathway during C. parapsilosis infection. Furthermore, we observed that Drosophila β-glucan receptor deficient flies where more sensitive to C. parapsilosis compared to wild-type flies; however, we could not find a clear dependence on the recognition of this receptor and the cell wall β-glucan exposure-induced host response. These studies establish this D. melanogaster infection model as an efficient tool in deciphering immune responses to C. parapsilosis as well as for assessing virulence factors produced by this emerging fungal predator.
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Affiliation(s)
- Katalin Csonka
- Department of Microbiology, Faculty of Science and Informatics, University of Szeged, Szeged, Hungary
| | - Zsolt Tasi
- Department of Microbiology, Faculty of Science and Informatics, University of Szeged, Szeged, Hungary
| | - Viktor Vedelek
- Department of Genetics, Faculty of Science and Informatics, University of Szeged, Szeged, Hungary
| | - Csaba Vágvölgyi
- Department of Microbiology, Faculty of Science and Informatics, University of Szeged, Szeged, Hungary
| | - Rita Sinka
- Department of Genetics, Faculty of Science and Informatics, University of Szeged, Szeged, Hungary
| | - Attila Gácser
- HCEMM-USZ, Department of Microbiology, Faculty of Science and Informatics, University of Szeged, Szeged, Hungary.,MTA-SZTE Lendület Mycobiome Research Group, University of Szeged, Szeged, Hungary
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20
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The Drosophila Baramicin polypeptide gene protects against fungal infection. PLoS Pathog 2021; 17:e1009846. [PMID: 34432851 PMCID: PMC8423362 DOI: 10.1371/journal.ppat.1009846] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Revised: 09/07/2021] [Accepted: 07/28/2021] [Indexed: 11/19/2022] Open
Abstract
The fruit fly Drosophila melanogaster combats microbial infection by producing a battery of effector peptides that are secreted into the haemolymph. Technical difficulties prevented the investigation of these short effector genes until the recent advent of the CRISPR/CAS era. As a consequence, many putative immune effectors remain to be formally described, and exactly how each of these effectors contribute to survival is not well characterized. Here we describe a novel Drosophila antifungal peptide gene that we name Baramicin A. We show that BaraA encodes a precursor protein cleaved into multiple peptides via furin cleavage sites. BaraA is strongly immune-induced in the fat body downstream of the Toll pathway, but also exhibits expression in other tissues. Importantly, we show that flies lacking BaraA are viable but susceptible to the entomopathogenic fungus Beauveria bassiana. Consistent with BaraA being directly antimicrobial, overexpression of BaraA promotes resistance to fungi and the IM10-like peptides produced by BaraA synergistically inhibit growth of fungi in vitro when combined with a membrane-disrupting antifungal. Surprisingly, BaraA mutant males but not females display an erect wing phenotype upon infection. Here, we characterize a new antifungal immune effector downstream of Toll signalling, and show it is a key contributor to the Drosophila antimicrobial response.
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Abstract
The gut microbiota affects the physiology and metabolism of animals and its alteration can lead to diseases such as gut dysplasia or metabolic disorders. Several reports have shown that the immune system plays an important role in shaping both bacterial community composition and abundance in Drosophila, and that immune deficit, especially during aging, negatively affects microbiota richness and diversity. However, there has been little study at the effector level to demonstrate how immune pathways regulate the microbiota. A key set of Drosophila immune effectors are the antimicrobial peptides (AMPs), which confer defense upon systemic infection. AMPs and lysozymes, a group of digestive enzymes with antimicrobial properties, are expressed in the gut and are good candidates for microbiota regulation. Here, we take advantage of the model organism Drosophila melanogaster to investigate the role of AMPs and lysozymes in regulation of gut microbiota structure and diversity. Using flies lacking AMPs and newly generated lysozyme mutants, we colonized gnotobiotic flies with a defined set of commensal bacteria and analyzed changes in microbiota composition and abundance in vertical transmission and aging contexts through 16S rRNA gene amplicon sequencing. Our study shows that AMPs and, to a lesser extent, lysozymes are necessary to regulate the total and relative abundance of bacteria in the gut microbiota. We also decouple the direct function of AMPs from the immune deficiency (IMD) signaling pathway that regulates AMPs but also many other processes, more narrowly defining the role of these effectors in the microbial dysbiosis observed in IMD-deficient flies upon aging.
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22
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Regulators and signalling in insect antimicrobial innate immunity: Functional molecules and cellular pathways. Cell Signal 2021; 83:110003. [PMID: 33836260 DOI: 10.1016/j.cellsig.2021.110003] [Citation(s) in RCA: 49] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Revised: 04/02/2021] [Accepted: 04/02/2021] [Indexed: 12/29/2022]
Abstract
Insects possess an immune system that protects them from attacks by various pathogenic microorganisms that would otherwise threaten their survival. Immune mechanisms may deal directly with the pathogens by eliminating them from the host organism or disarm them by suppressing the synthesis of toxins and virulence factors that promote the invasion and destructive action of the intruder within the host. Insects have been established as outstanding models for studying immune system regulation because innate immunity can be explored as an integrated system at the level of the whole organism. Innate immunity in insects consists of basal immunity that controls the constitutive synthesis of effector molecules such as antimicrobial peptides, and inducible immunity that is activated after detection of a microbe or its product(s). Activation and coordination of innate immune defenses in insects involve evolutionary conserved immune factors. Previous research in insects has led to the identification and characterization of distinct immune signalling pathways that modulate the response to microbial infections. This work has not only advanced the field of insect immunology, but it has also rekindled interest in the innate immune system of mammals. Here we review the current knowledge on key molecular components of insect immunity and discuss the opportunities they present for confronting infectious diseases in humans.
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