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Critchlow JT, Prakash A, Zhong KY, Tate AT. Mapping the functional form of the trade-off between infection resistance and reproductive fitness under dysregulated immune signaling. PLoS Pathog 2024; 20:e1012049. [PMID: 38408106 PMCID: PMC10919860 DOI: 10.1371/journal.ppat.1012049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2023] [Revised: 03/07/2024] [Accepted: 02/15/2024] [Indexed: 02/28/2024] Open
Abstract
Immune responses benefit organismal fitness by clearing parasites but also exact costs associated with immunopathology and energetic investment. Hosts manage these costs by tightly regulating the induction of immune signaling to curtail excessive responses and restore homeostasis. Despite the theoretical importance of turning off the immune response to mitigate these costs, experimentally connecting variation in the negative regulation of immune responses to organismal fitness remains a frontier in evolutionary immunology. In this study, we used a dose-response approach to manipulate the RNAi-mediated knockdown efficiency of cactus (IκBα), a central regulator of Toll pathway signal transduction in flour beetles (Tribolium castaneum). By titrating cactus activity across four distinct levels, we derived the shape of the relationship between immune response investment and traits associated with host fitness, including infection susceptibility, lifespan, fecundity, body mass, and gut homeostasis. Cactus knock-down increased the overall magnitude of inducible immune responses and delayed their resolution in a dsRNA dose-dependent manner, promoting survival and resistance following bacterial infection. However, these benefits were counterbalanced by dsRNA dose-dependent costs to lifespan, fecundity, body mass, and gut integrity. Our results allowed us to move beyond the qualitative identification of a trade-off between immune investment and fitness to actually derive its functional form. This approach paves the way to quantitatively compare the evolution and impact of distinct regulatory elements on life-history trade-offs and fitness, filling a crucial gap in our conceptual and theoretical models of immune signaling network evolution and the maintenance of natural variation in immune systems.
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Affiliation(s)
- Justin T Critchlow
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, United States of America
| | - Arun Prakash
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, United States of America
| | - Katherine Y Zhong
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, United States of America
| | - Ann T Tate
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, United States of America
- Evolutionary Studies Institute, Vanderbilt University, Nashville, Tennessee, United States of America
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2
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Telleria EL, Tinoco-Nunes B, Forrest DM, Di-Blasi T, Leštinová T, Chang KP, Volf P, Pitaluga AN, Traub-Csekö YM. Evidence of a conserved mammalian immunosuppression mechanism in Lutzomyia longipalpis upon infection with Leishmania. Front Immunol 2023; 14:1162596. [PMID: 38022562 PMCID: PMC10652419 DOI: 10.3389/fimmu.2023.1162596] [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: 02/09/2023] [Accepted: 10/13/2023] [Indexed: 12/01/2023] Open
Abstract
Introduction Sand flies (Diptera: Phlebotominae) belonging to the Lutzomyia genus transmit Leishmania infantum parasites. To understand the complex interaction between the vector and the parasite, we have been investigating the sand fly immune responses during the Leishmania infection. Our previous studies showed that genes involved in the IMD, Toll, and Jak-STAT immunity pathways are regulated upon Leishmania and bacterial challenges. Nevertheless, the parasite can thrive in the vectors' gut, indicating the existence of mechanisms capable of modulating the vector defenses, as was already seen in mammalian Leishmania infections. Methods results and discussion In this study, we investigated the expression of Lutzomyia longipalpis genes involved in regulating the Toll pathway under parasitic infection. Leishmania infantum infection upregulated the expression of two L. longipalpis genes coding for the putative repressors cactus and protein tyrosine phosphatase SHP. These findings suggest that the parasite can modulate the vectors' immune response. In mammalian infections, the Leishmania surface glycoprotein GP63 is one of the inducers of host immune depression, and one of the known effectors is SHP. In L. longipalpis we found a similar effect: a genetically modified strain of Leishmania amazonensis over-expressing the metalloprotease GP63 induced a higher expression of the sand fly SHP indicating that the L. longipalpis SHP and parasite GP63 increased expressions are connected. Immuno-stained microscopy of L. longipalpis LL5 embryonic cells cultured with Leishmania strains or parasite conditioned medium showed cells internalization of parasite GP63. A similar internalization of GP63 was observed in the sand fly gut tissue after feeding on parasites, parasite exosomes, or parasite conditioned medium, indicating that GP63 can travel through cells in vitro or in vivo. When the sand fly SHP gene was silenced by RNAi and females infected by L. infantum, parasite loads decreased in the early phase of infection as expected, although no significant differences were seen in late infections of the stomodeal valve. Conclusions Our findings show the possible role of a pathway repressor involved in regulating the L. longipalpis immune response during Leishmania infections inside the insect. In addition, they point out a conserved immunosuppressive effect of GP63 between mammals and sand flies in the early stage of parasite infection.
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Affiliation(s)
- Erich Loza Telleria
- Department of Parasitology, Faculty of Science, Charles University, Prague, Czechia
| | - Bruno Tinoco-Nunes
- Laboratório de Biologia Molecular de Parasitas e Vetores, Instituto Oswaldo Cruz - Fiocruz, Rio de Janeiro, RJ, Brazil
| | - David M. Forrest
- Laboratório de Biologia Molecular de Parasitas e Vetores, Instituto Oswaldo Cruz - Fiocruz, Rio de Janeiro, RJ, Brazil
| | - Tatiana Di-Blasi
- Laboratório de Biologia Molecular de Parasitas e Vetores, Instituto Oswaldo Cruz - Fiocruz, Rio de Janeiro, RJ, Brazil
| | - Tereza Leštinová
- Department of Parasitology, Faculty of Science, Charles University, Prague, Czechia
| | - Kwang Poo Chang
- Department of Microbiology and Immunology, Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, IL, United States
| | - Petr Volf
- Department of Parasitology, Faculty of Science, Charles University, Prague, Czechia
| | - André Nóbrega Pitaluga
- Laboratório de Biologia Molecular de Parasitas e Vetores, Instituto Oswaldo Cruz - Fiocruz, Rio de Janeiro, RJ, Brazil
| | - Yara Maria Traub-Csekö
- Laboratório de Biologia Molecular de Parasitas e Vetores, Instituto Oswaldo Cruz - Fiocruz, Rio de Janeiro, RJ, Brazil
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3
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Critchlow JT, Prakash A, Zhong KY, Tate AT. Mapping the functional form of the trade-off between infection resistance and reproductive fitness under dysregulated immune signaling. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.10.552815. [PMID: 37645726 PMCID: PMC10461925 DOI: 10.1101/2023.08.10.552815] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/31/2023]
Abstract
Immune responses benefit organismal fitness by clearing parasites but also exact costs associated with immunopathology and energetic investment. Hosts manage these costs by tightly regulating the induction of immune signaling to curtail excessive responses and restore homeostasis. Despite the theoretical importance of turning off the immune response to mitigate these costs, experimentally connecting variation in the negative regulation of immune responses to organismal fitness remains a frontier in evolutionary immunology. In this study, we used a dose-response approach to manipulate the RNAi-mediated knockdown efficiency of cactus (IκBα), a central regulator of Toll pathway signal transduction in flour beetles (Tribolium castaneum). By titrating cactus activity along a continuous gradient, we derived the shape of the relationship between immune response investment and traits associated with host fitness, including infection susceptibility, lifespan, fecundity, body mass, and gut homeostasis. Cactus knock-down increased the overall magintude of inducible immune responses and delayed their resolution in a dsRNA dose-dependent manner, promoting survival and resistance following bacterial infection. However, these benefits were counterbalanced by dsRNA dose-dependent costs to lifespan, fecundity, body mass, and gut integrity. Our results allowed us to move beyond the qualitative identification of a trade-off between immune investment and fitness to actually derive its functional form. This approach paves the way to quantitatively compare the evolution and impact of distinct regulatory elements on life-history trade-offs and fitness, filling a crucial gap in our conceptual and theoretical models of immune signaling network evolution and the maintenance of natural variation in immune systems.
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Affiliation(s)
- Justin T. Critchlow
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, United States of America
| | - Arun Prakash
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, United States of America
| | - Katherine Y. Zhong
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, United States of America
| | - Ann T. Tate
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, United States of America
- Evolutionary Studies Institute, Vanderbilt University, Nashville, Tennessee, United States of America
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4
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Shit B, Prakash A, Sarkar S, Vale PF, Khan I. Ageing leads to reduced specificity of antimicrobial peptide responses in Drosophila melanogaster. Proc Biol Sci 2022; 289:20221642. [PMID: 36382522 PMCID: PMC9667363 DOI: 10.1098/rspb.2022.1642] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2022] [Accepted: 10/24/2022] [Indexed: 11/17/2022] Open
Abstract
Evolutionary theory predicts a late-life decline in the force of natural selection, possibly leading to late-life deregulations of the immune system. A potential outcome of such deregulations is the inability to produce specific immunity against target pathogens. We tested this possibility by infecting multiple Drosophila melanogaster lines (with bacterial pathogens) across age groups, where either individual or different combinations of Imd- and Toll-inducible antimicrobial peptides (AMPs) were deleted using CRISPR gene editing. We show a high degree of non-redundancy and pathogen-specificity of AMPs in young flies: in some cases, even a single AMP could confer complete resistance. However, ageing led to drastic reductions in such specificity to target pathogens, warranting the action of multiple AMPs across Imd and Toll pathways. Moreover, use of diverse AMPs either lacked survival benefits or even accompanied survival costs post-infection. These features were also sexually dimorphic: females required a larger repertoire of AMPs than males but extracted equivalent survival benefits. Finally, age-specific expansion of the AMP-repertoire was accompanied with ageing-induced downregulation of negative-regulators of the Imd pathway and damage to renal function post-infection, as features of poorly regulated immunity. Overall, we could highlight the potentially non-adaptive role of ageing in producing less-specific AMP responses, across sexes and pathogens.
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Affiliation(s)
- Biswajit Shit
- Ashoka University, Plot No. 2, Rajiv Gandhi Education City, National Capital Region P.O. Rai, Sonepat, Haryana-131029, India
| | - Arun Prakash
- Institute of Ecology and Evolution, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3FL, UK
| | - Saubhik Sarkar
- Ashoka University, Plot No. 2, Rajiv Gandhi Education City, National Capital Region P.O. Rai, Sonepat, Haryana-131029, India
| | - Pedro F. Vale
- Institute of Ecology and Evolution, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3FL, UK
| | - Imroze Khan
- Ashoka University, Plot No. 2, Rajiv Gandhi Education City, National Capital Region P.O. Rai, Sonepat, Haryana-131029, India
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5
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Masuzzo A, Manière G, Grosjean Y, Kurz L, Royet J. Bacteria-Derived Peptidoglycan Triggers a Noncanonical Nuclear Factor-κB-Dependent Response in Drosophila Gustatory Neurons. J Neurosci 2022; 42:7809-7823. [PMID: 36414007 PMCID: PMC9581565 DOI: 10.1523/jneurosci.2437-21.2022] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Revised: 07/13/2022] [Accepted: 07/15/2022] [Indexed: 12/14/2022] Open
Abstract
Probing the external world is essential for eukaryotes to distinguish beneficial from pathogenic micro-organisms. If it is clear that the main part of this task falls to the immune cells, recent work shows that neurons can also detect microbes, although the molecules and mechanisms involved are less characterized. In Drosophila, detection of bacteria-derived peptidoglycan by pattern recognition receptors of the peptidoglycan recognition protein (PGRP) family expressed in immune cells triggers nuclear factor-κB (NF-κB)/immune deficiency (IMD)-dependent signaling. We show here that one PGRP protein, called PGRP-LB, is expressed in bitter gustatory neurons of proboscises. In vivo calcium imaging in female flies reveals that the PGRP/IMD pathway is cell-autonomously required in these neurons to transduce the peptidoglycan signal. We finally show that NF-κB/IMD pathway activation in bitter-sensing gustatory neurons influences fly behavior. This demonstrates that a major immune response elicitor and signaling module are required in the peripheral nervous system to sense the presence of bacteria in the environment.SIGNIFICANCE STATEMENT In addition to the classical immune response, eukaryotes rely on neuronally controlled mechanisms to detect microbes and engage in adapted behaviors. However, the mechanisms of microbe detection by the nervous system are poorly understood. Using genetic analysis and calcium imaging, we demonstrate here that bacteria-derived peptidoglycan can activate bitter gustatory neurons. We further show that this response is mediated by the PGRP-LC membrane receptor and downstream components of a noncanonical NF-κB signaling cascade. Activation of this signaling cascade triggers behavior changes. These data demonstrate that bitter-sensing neurons and immune cells share a common detection and signaling module to either trigger the production of antibacterial effectors or to modulate the behavior of flies that are in contact with bacteria. Because peptidoglycan detection doesn't mobilize the known gustatory receptors, it also demonstrates that taste perception is much more complex than anticipated.
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Affiliation(s)
- Ambra Masuzzo
- Centre National de la Recherche Scientifique, Aix-Marseille Université, Institut de Biologie du Developpement de Marseille, 13009 Marseille, France
| | - Gérard Manière
- Centre National de la Recherche Scientifique; Institut National de Recherche pour l'Agriculture, l'Alimentation et l'Environnement; Université Bourgogne Franche-Comté, Centre des Sciences du Goût et de l'Alimentation, L'Institut Agro Dijon, Dijon 21000, France
| | - Yaël Grosjean
- Centre National de la Recherche Scientifique; Institut National de Recherche pour l'Agriculture, l'Alimentation et l'Environnement; Université Bourgogne Franche-Comté, Centre des Sciences du Goût et de l'Alimentation, L'Institut Agro Dijon, Dijon 21000, France
| | - Léopold Kurz
- Centre National de la Recherche Scientifique, Aix-Marseille Université, Institut de Biologie du Developpement de Marseille, 13009 Marseille, France
| | - Julien Royet
- Centre National de la Recherche Scientifique, Aix-Marseille Université, Institut de Biologie du Developpement de Marseille, 13009 Marseille, France
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Hua Y, Zhu Y, Hu Y, Kong F, Duan R, Zhang C, Zhang C, Zhang S, Jin Y, Ye Y, Cai Q, Ji S. A Feedback Regulatory Loop Involving dTrbd/dTak1 in Controlling IMD Signaling in Drosophila Melanogaster. Front Immunol 2022; 13:932268. [PMID: 35911722 PMCID: PMC9329959 DOI: 10.3389/fimmu.2022.932268] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Accepted: 06/23/2022] [Indexed: 11/23/2022] Open
Abstract
Negative regulators of the inflammatory responses are essential for the maintenance of immune homeostasis and organismal fitness. In Drosophila, the deubiquitinase (Dub) dTrbd selectively restricts the K63-linked ubiquitination modification of dTak1, a pivotal kinase of the IMD signaling pathway, to regulate the IMD innate immune response. However, which domain and how it functions to enable dTrbd's activity remain unexplored. Here, we provide compelling evidence showing that the NZF domain of dTrbd is essential for its association with dTak1. Meanwhile, the Linker region of dTrbd is involved in modulating its condensation, a functional state representing the Dub enzymatical activity of dTrbd. Of interest, the activated IMD signals following bacterial stimuli enhance the dTrbd/dTak1 interaction, as well as the condensate assembly and Dub enzymatical activity of dTrbd. Collectively, our studies shed light on the dual mechanisms by which the IMD signaling-mediated feedback loop of dTrbd/dTak1 precisely regulates the innate immune response in Drosophila.
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Affiliation(s)
- Yongzhi Hua
- Centre for Developmental Biology, School of Life Sciences, Anhui Agricultural University, Hefei, China
| | - Yangyang Zhu
- Centre for Developmental Biology, School of Life Sciences, Anhui Agricultural University, Hefei, China
| | - Yixuan Hu
- Centre for Developmental Biology, School of Life Sciences, Anhui Agricultural University, Hefei, China
| | - Fanrui Kong
- Centre for Developmental Biology, School of Life Sciences, Anhui Agricultural University, Hefei, China
| | - Renjie Duan
- Centre for Developmental Biology, School of Life Sciences, Anhui Agricultural University, Hefei, China
- School of Preclinical Medicine, Wannan Medical College, Wuhu, China
| | - Chao Zhang
- Centre for Developmental Biology, School of Life Sciences, Anhui Agricultural University, Hefei, China
| | - Chuchu Zhang
- Centre for Developmental Biology, School of Life Sciences, Anhui Agricultural University, Hefei, China
| | - Shikun Zhang
- Centre for Developmental Biology, School of Life Sciences, Anhui Agricultural University, Hefei, China
| | - Yiheng Jin
- Centre for Developmental Biology, School of Life Sciences, Anhui Agricultural University, Hefei, China
| | - Yizhu Ye
- Centre for Developmental Biology, School of Life Sciences, Anhui Agricultural University, Hefei, China
| | - Qingshuang Cai
- Centre for Developmental Biology, School of Life Sciences, Anhui Agricultural University, Hefei, China
| | - Shanming Ji
- Centre for Developmental Biology, School of Life Sciences, Anhui Agricultural University, Hefei, China
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7
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Prakash P, Roychowdhury-Sinha A, Goto A. Verloren negatively regulates the expression of IMD pathway dependent antimicrobial peptides in Drosophila. Sci Rep 2021; 11:15549. [PMID: 34330981 PMCID: PMC8324896 DOI: 10.1038/s41598-021-94973-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Accepted: 07/16/2021] [Indexed: 11/08/2022] Open
Abstract
Drosophila immune deficiency (IMD) pathway is similar to the human tumor necrosis factor receptor (TNFR) signaling pathway and is preferentially activated by Gram-negative bacterial infection. Recent studies highlighted the importance of IMD pathway regulation as it is tightly controlled by numbers of negative regulators at multiple levels. Here, we report a new negative regulator of the IMD pathway, Verloren (Velo). Silencing of Velo led to constitutive expression of the IMD pathway dependent antimicrobial peptides (AMPs), and Escherichia coli stimulation further enhanced the AMP expression. Epistatic analysis indicated that Velo knock-down mediated AMP upregulation is dependent on the canonical members of the IMD pathway. The immune fluorescent study using overexpression constructs revealed that Velo resides both in the nucleus and cytoplasm, but the majority (~ 75%) is localized in the nucleus. We also observed from in vivo analysis that Velo knock-down flies exhibit significant upregulation of the AMP expression and reduced bacterial load. Survival experiments showed that Velo knock-down flies have a short lifespan and are susceptible to the infection of pathogenic Gram-negative bacteria, P. aeruginosa. Taken together, these data suggest that Velo is an additional new negative regulator of the IMD pathway, possibly acting in both the nucleus and cytoplasm.
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Affiliation(s)
- Pragya Prakash
- INSERM, Université de Strasbourg, CNRS, Insect Models of Innate Immunity (M3I; UPR9022), 67084, Strasbourg, France
| | | | - Akira Goto
- INSERM, Université de Strasbourg, CNRS, Insect Models of Innate Immunity (M3I; UPR9022), 67084, Strasbourg, France.
- Sino-French Hoffmann Institute, School of Basic Medical Science, Guangzhou Medical University, Guangzhou, 511436, China.
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8
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Arora S, Ligoxygakis P. Beyond Host Defense: Deregulation of Drosophila Immunity and Age-Dependent Neurodegeneration. Front Immunol 2020; 11:1574. [PMID: 32774336 PMCID: PMC7387716 DOI: 10.3389/fimmu.2020.01574] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Accepted: 06/15/2020] [Indexed: 12/12/2022] Open
Abstract
Age-dependent neurodegenerative disorders are a set of diseases that affect millions of individuals worldwide. Apart from a small subset that are the result of well-defined inherited autosomal dominant gene mutations (e.g., those encoding the β-amyloid precursor protein and presenilins), our understanding of the genetic network that underscores their pathology, remains scarce. Genome-wide association studies (GWAS) especially in Alzheimer's disease patients and research in Parkinson's disease have implicated inflammation and the innate immune response as risk factors. However, even if GWAS etiology points toward innate immunity, untangling cause, and consequence is a challenging task. Specifically, it is not clear whether predisposition to de-regulated immunity causes an inadequate response to protein aggregation (such as amyloid or α-synuclein) or is the direct cause of this aggregation. Given the evolutionary conservation of the innate immune response in Drosophila and humans, unraveling whether hyperactive immune response in glia have a protective or pathological role in the brain could be a potential strategy in combating age-related neurological diseases.
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Affiliation(s)
- Srishti Arora
- Laboratory of Cell Biology, Development and Genetics, Department of Biochemistry, University of Oxford, Oxford, United Kingdom
| | - Petros Ligoxygakis
- Laboratory of Cell Biology, Development and Genetics, Department of Biochemistry, University of Oxford, Oxford, United Kingdom
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9
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Charroux B, Daian F, Royet J. Drosophila Aversive Behavior toward Erwinia carotovora carotovora Is Mediated by Bitter Neurons and Leukokinin. iScience 2020; 23:101152. [PMID: 32450516 PMCID: PMC7251953 DOI: 10.1016/j.isci.2020.101152] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Revised: 03/02/2020] [Accepted: 05/06/2020] [Indexed: 12/18/2022] Open
Abstract
The phytopathogen Erwinia carotovora carotovora (Ecc) has been used successfully to decipher some of the mechanisms that regulate the interactions between Drosophila melanogaster and bacteria, mostly following forced association between the two species. How do Drosophila normally perceive and respond to the presence of Ecc is unknown. Using a fly feeding two-choice assay and video tracking, we show that Drosophila are first attracted but then repulsed by an Ecc-contaminated solution. The initial attractive phase is dependent on the olfactory Gr63a and Gαq proteins, whereas the second repulsive phase requires a functional gustatory system. Genetic manipulations and calcium imaging indicate that bitter neurons and gustatory receptors Gr66a and Gr33a are needed for the aversive phase and that the neuropeptide leukokinin is also involved. We also demonstrate that these behaviors are independent of the NF-κB cascade that controls some of the immune, metabolic, and behavioral responses to bacteria.
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Affiliation(s)
| | - Fabrice Daian
- Aix-Marseille Université, CNRS, IBDM, Marseille, France
| | - Julien Royet
- Aix-Marseille Université, CNRS, IBDM, Marseille, France.
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10
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Colombani J, Andersen DS. The
Drosophila
gut: A gatekeeper and coordinator of organism fitness and physiology. WILEY INTERDISCIPLINARY REVIEWS-DEVELOPMENTAL BIOLOGY 2020; 9:e378. [DOI: 10.1002/wdev.378] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2019] [Revised: 02/03/2020] [Accepted: 02/17/2020] [Indexed: 12/31/2022]
Affiliation(s)
- Julien Colombani
- Department of Biology, Faculty of Science University of Copenhagen Copenhagen O Denmark
- Novo Nordisk Foundation Center for Stem Cell Research, Faculty of Health and Medical Science University of Copenhagen Copenhagen N Denmark
| | - Ditte S. Andersen
- Department of Biology, Faculty of Science University of Copenhagen Copenhagen O Denmark
- Novo Nordisk Foundation Center for Stem Cell Research, Faculty of Health and Medical Science University of Copenhagen Copenhagen N Denmark
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11
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Innate immune responses to paraquat exposure in a Drosophila model of Parkinson's disease. Sci Rep 2019; 9:12714. [PMID: 31481676 PMCID: PMC6722124 DOI: 10.1038/s41598-019-48977-6] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2019] [Accepted: 08/13/2019] [Indexed: 12/25/2022] Open
Abstract
Parkinson’s disease (PD) is a progressive, neurodegenerative movement disorder characterized by the loss of dopaminergic (DA) neurons. Limited understanding of the early molecular pathways associated with the demise of DA neurons, including those of inflammatory exacerbation of neurodegeneration, is a major impediment to therapeutic development. Recent studies have implicated gene-environment interactions in PD susceptibility. We used transcriptomic profiling in a Drosophila PD model in response to paraquat (PQ)-induced oxidative stress to identify pre-symptomatic signatures of impending neuron dysfunction. Our RNAseq data analysis revealed extensive regulation of innate immune response genes following PQ ingestion. We found that PQ exposure leads to the activation of the NF-κB transcription factor, Relish, and the stress signaling factor JNK, encoded by the gene basket in Drosophila. Relish knockdown in the dopaminergic neurons confers PQ resistance and rescues mobility defects and DA neuron loss. Furthermore, PQ-induced toxicity is mediated through the immune deficiency signaling pathway. Surprisingly, the expression of Relish-dependent anti-microbial peptide (AMPs) genes is suppressed upon PQ exposure causing increased sensitivity to Gram-negative bacterial infection. This work provides a novel link between PQ exposure and innate immune system modulation underlying environmental toxin-induced neurodegeneration, thereby underscoring the role of the innate immune system in PD pathogenesis.
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12
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Affiliation(s)
- Steven A. Frank
- Department of Ecology and Evolutionary Biology, University of California, Irvine, California, United States of America
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13
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Swevers L, Liu J, Smagghe G. Defense Mechanisms against Viral Infection in Drosophila: RNAi and Non-RNAi. Viruses 2018; 10:E230. [PMID: 29723993 PMCID: PMC5977223 DOI: 10.3390/v10050230] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2018] [Revised: 04/20/2018] [Accepted: 04/27/2018] [Indexed: 12/20/2022] Open
Abstract
RNAi is considered a major antiviral defense mechanism in insects, but its relative importance as compared to other antiviral pathways has not been evaluated comprehensively. Here, it is attempted to give an overview of the antiviral defense mechanisms in Drosophila that involve both RNAi and non-RNAi. While RNAi is considered important in most viral infections, many other pathways can exist that confer antiviral resistance. It is noted that very few direct recognition mechanisms of virus infections have been identified in Drosophila and that the activation of immune pathways may be accomplished indirectly through cell damage incurred by viral replication. In several cases, protection against viral infection can be obtained in RNAi mutants by non-RNAi mechanisms, confirming the variability of the RNAi defense mechanism according to the type of infection and the physiological status of the host. This analysis is aimed at more systematically investigating the relative contribution of RNAi in the antiviral response and more specifically, to ask whether RNAi efficiency is affected when other defense mechanisms predominate. While Drosophila can function as a useful model, this issue may be more critical for economically important insects that are either controlled (agricultural pests and vectors of diseases) or protected from parasite infection (beneficial insects as bees) by RNAi products.
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Affiliation(s)
- Luc Swevers
- Institute of Biosciences & Applications, NCSR "Demokritos", 15341 Athens, Greece.
| | - Jisheng Liu
- School of Life Sciences, Guangzhou University, 510006 Guangzhou, China.
| | - Guy Smagghe
- Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, 9000 Ghent, Belgium.
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14
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Wei G, Sun L, Li R, Li L, Xu J, Ma F. Dynamic miRNA-mRNA regulations are essential for maintaining Drosophila immune homeostasis during Micrococcus luteus infection. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2018; 81:210-224. [PMID: 29198775 DOI: 10.1016/j.dci.2017.11.019] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2017] [Revised: 11/15/2017] [Accepted: 11/29/2017] [Indexed: 06/07/2023]
Abstract
Pathogen bacteria infections can lead to dynamic changes of microRNA (miRNA) and mRNA expression profiles, which may control synergistically the outcome of immune responses. To reveal the role of dynamic miRNA-mRNA regulation in Drosophila innate immune responses, we have detailedly analyzed the paired miRNA and mRNA expression profiles at three time points during Drosophila adult males with Micrococcus luteus (M. luteus) infection using RNA- and small RNA-seq data. Our results demonstrate that differentially expressed miRNAs and mRNAs represent extensively dynamic changes over three time points during Drosophila with M. luteus infection. The pathway enrichment analysis indicates that differentially expressed genes are involved in diverse signaling pathways, including Toll and Imd as well as orther signaling pathways at three time points during Drosophila with M. luteus infection. Remarkably, the dynamic change of miRNA expression is delayed by compared to mRNA expression change over three time points, implying that the "time" parameter should be considered when the function of miRNA/mRNA is further studied. In particular, the dynamic miRNA-mRNA regulatory networks have shown that miRNAs may synergistically regulate gene expressions of different signaling pathways to promote or inhibit innate immune responses and maintain homeostasis in Drosophila, and some new regulators involved in Drosophila innate immune response have been identified. Our findings strongly suggest that miRNA regulation is a key mechanism involved in fine-tuning cooperatively gene expressions of diverse signaling pathways to maintain innate immune response and homeostasis in Drosophila. Taken together, the present study reveals a novel role of dynamic miRNA-mRNA regulation in immune response to bacteria infection, and provides a new insight into the underlying molecular regulatory mechanism of Drosophila innate immune responses.
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Affiliation(s)
- Guanyun Wei
- Laboratory for Comparative Genomics and Bioinformatics, Jiangsu Key Laboratory for Biodiversity and Biotechnology, College of Life Science, Nanjing Normal University, Nanjing 210046, China
| | - Lianjie Sun
- Laboratory for Comparative Genomics and Bioinformatics, Jiangsu Key Laboratory for Biodiversity and Biotechnology, College of Life Science, Nanjing Normal University, Nanjing 210046, China
| | - Ruimin Li
- Laboratory for Comparative Genomics and Bioinformatics, Jiangsu Key Laboratory for Biodiversity and Biotechnology, College of Life Science, Nanjing Normal University, Nanjing 210046, China
| | - Lei Li
- Laboratory for Comparative Genomics and Bioinformatics, Jiangsu Key Laboratory for Biodiversity and Biotechnology, College of Life Science, Nanjing Normal University, Nanjing 210046, China; Laboratory of Intelligent Computation, School of Computer Science, Nanjing Normal University, Nanjing 210046, China
| | - Jiao Xu
- Laboratory for Comparative Genomics and Bioinformatics, Jiangsu Key Laboratory for Biodiversity and Biotechnology, College of Life Science, Nanjing Normal University, Nanjing 210046, China
| | - Fei Ma
- Laboratory for Comparative Genomics and Bioinformatics, Jiangsu Key Laboratory for Biodiversity and Biotechnology, College of Life Science, Nanjing Normal University, Nanjing 210046, China.
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15
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Charroux B, Capo F, Kurz CL, Peslier S, Chaduli D, Viallat-Lieutaud A, Royet J. Cytosolic and Secreted Peptidoglycan-Degrading Enzymes in Drosophila Respectively Control Local and Systemic Immune Responses to Microbiota. Cell Host Microbe 2018; 23:215-228.e4. [PMID: 29398649 DOI: 10.1016/j.chom.2017.12.007] [Citation(s) in RCA: 67] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2017] [Revised: 10/10/2017] [Accepted: 12/14/2017] [Indexed: 12/19/2022]
Abstract
Gut-associated bacteria produce metabolites that both have a local influence on the intestinal tract and act at a distance on remote organs. In Drosophila, bacteria-derived peptidoglycan (PGN) displays such a dual role. PGN triggers local antimicrobial peptide production by enterocytes; it also activates systemic immune responses in fat-body cells and modulates fly behavior by acting on neurons. How these responses to a single microbiota-derived compound are simultaneously coordinated is not understood. We show here that the PGRP-LB locus generates both cytosolic and secreted PGN-cleaving enzymes. Through genetic analysis, we demonstrate that the cytosolic PGRP-LB isoforms cell-autonomously control the intensity of NF-κB activation in enterocytes, whereas the secreted isoform prevents massive and detrimental gut-derived PGN dissemination throughout the organism. This study explains how Drosophila are able to uncouple the modulation of local versus systemic responses to a single gut-bacteria-derived product by using isoform-specific enzymes.
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Affiliation(s)
| | - Florence Capo
- Aix Marseille Université, CNRS, IBDM, Marseille, France
| | | | | | | | | | - Julien Royet
- Aix Marseille Université, CNRS, IBDM, Marseille, France.
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16
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Maki K, Shibata T, Kawabata SI. Transglutaminase-catalyzed incorporation of polyamines masks the DNA-binding region of the transcription factor Relish. J Biol Chem 2017; 292:6369-6380. [PMID: 28258224 DOI: 10.1074/jbc.m117.779579] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2017] [Revised: 02/27/2017] [Indexed: 02/01/2023] Open
Abstract
In Drosophila, the final immune deficiency (IMD) pathway-dependent signal is transmitted through proteolytic conversion of the nuclear factor-κB (NF-κB)-like transcription factor Relish to the active N-terminal fragment Relish-N. Relish-N is then translocated from the cytosol into the nucleus for the expression of IMD-controlled genes. We previously demonstrated that transglutaminase (TG) suppresses the IMD pathway by polymerizing Relish-N to inhibit its nuclear translocation. Conversely, we also demonstrated that orally ingested synthetic amines, such as monodansylcadaverine (DCA) and biotin-labeled pentylamine, are TG-dependently incorporated into Relish-N, causing the nuclear translocation of modified Relish-N in gut epithelial cells. It remains unclear, however, whether polyamine-containing Relish-N retains transcriptional activity. Here, we used mass spectrometry analysis of a recombinant Relish-N modified with DCA by TG activity after proteolytic digestion and show that the DCA-modified Gln residues are located in the DNA-binding region of Relish-N. TG-catalyzed DCA incorporation inhibited binding of Relish-N to the Rel-responsive element in the NF-κB-binding DNA sequence. Subcellular fractionation of TG-expressing Drosophila S2 cells indicated that TG was localized in both the cytosol and nucleus. Of note, natural polyamines, including spermidine and spermine, competitively inhibited TG-dependent DCA incorporation into Relish-N. Moreover, in vivo experiments demonstrated that Relish-N was modified by spermine and that this modification reduced transcription of IMD pathway-controlled cecropin A1 and diptericin genes. These findings suggest that intracellular TG regulates Relish-N-mediated transcriptional activity by incorporating polyamines into Relish-N and via protein-protein cross-linking.
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Affiliation(s)
- Kouki Maki
- From the Graduate School of Systems Life Sciences
| | - Toshio Shibata
- Institute for Advanced Study, and.,Department of Biology, Faculty of Science, Kyushu University, Fukuoka 819-0395, Japan
| | - Shun-Ichiro Kawabata
- From the Graduate School of Systems Life Sciences, .,Department of Biology, Faculty of Science, Kyushu University, Fukuoka 819-0395, Japan
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17
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Inhibition of a NF-κB/Diap1 Pathway by PGRP-LF Is Required for Proper Apoptosis during Drosophila Development. PLoS Genet 2017; 13:e1006569. [PMID: 28085885 PMCID: PMC5279808 DOI: 10.1371/journal.pgen.1006569] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Revised: 01/30/2017] [Accepted: 01/04/2017] [Indexed: 12/15/2022] Open
Abstract
NF-κB pathways are key signaling cascades of the Drosophila innate immune response. One of them, the Immune Deficiency (IMD) pathway, is under a very tight negative control. Although molecular brakes exist at each step of this signaling module from ligand availability to transcriptional regulation, it remains unknown whether repressors act in the same cells or tissues and if not, what is rationale behind this spatial specificity. We show here that the negative regulator of IMD pathway PGRP-LF is epressed in ectodermal derivatives. We provide evidence that, in the absence of any immune elicitor, PGRP-LF loss-of-function mutants, display a constitutive NF-κB/IMD activation specifically in ectodermal tissues leading to genitalia and tergite malformations. In agreement with previous data showing that proper development of these structures requires induction of apoptosis, we show that ectopic activation of NF-κB/IMD signaling leads to apoptosis inhibition in both genitalia and tergite primordia. We demonstrate that NF-κB/IMD signaling antagonizes apoptosis by up-regulating expression of the anti-apoptotic protein Diap1. Altogether these results show that, in the complete absence of infection, the negative regulation of NF-κB/IMD pathway by PGRP-LF is crucial to ensure proper induction of apoptosis and consequently normal fly development. These results highlight that IMD pathway regulation is controlled independently in different tissues, probably reflecting the different roles of this signaling cascade in both developmental and immune processes. In multicellular organism such as mammals or insects, activation of innate immune responses occurs following detection of microbes by dedicated receptors called pattern recognition receptors. Such immune activation is taking place in immune competent tissue such as the skin, the digestive and respiratory epithelia and is under a tight negative control. Negative control is essential to finely adjust the duration and the intensity of the immune response to the level of infection. We found that the Drosophila innate immunity negative regulator PGRP-LF, is specifically expressed in non-immune tissues and plays an essential role during development, in absence of any infection. Lack of PGRP-LF function in these tissues inhibits apoptosis leading to incomplete genitalia rotation and tergite malformations. We show that such apoptosis inhibition results from the over expression of the negative regulator of apoptosis Diap1 specifically in PGRP-LF expressing cells. Our data highlight that proper negative regulation of immune signaling pathway in non-immune tissues is contributing to normal development and illustrate the growing evidence of the dual role of immune signaling pathway contribution to both immunity and in development processes.
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18
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Matetovici I, Caljon G, Van Den Abbeele J. Tsetse fly tolerance to T. brucei infection: transcriptome analysis of trypanosome-associated changes in the tsetse fly salivary gland. BMC Genomics 2016; 17:971. [PMID: 27884110 PMCID: PMC5123318 DOI: 10.1186/s12864-016-3283-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2016] [Accepted: 11/09/2016] [Indexed: 12/03/2022] Open
Abstract
Background For their transmission, African trypanosomes rely on their blood feeding insect vector, the tsetse fly (Glossina sp.). The ingested Trypanosoma brucei parasites have to overcome a series of barriers in the tsetse fly alimentary tract to finally develop into the infective metacyclic forms in the salivary glands that are transmitted to a mammalian host by the tsetse bite. The parasite population in the salivary gland is dense with a significant number of trypanosomes tightly attached to the epithelial cells. Our current knowledge on the impact of the infection on the salivary gland functioning is very limited. Therefore, this study aimed to gain a deeper insight into the global gene expression changes in the salivary glands of Glossina morsitans morsitans in response to an infection with the T. brucei parasite. A detailed whole transcriptome comparison of midgut-infected tsetse with and without a mature salivary gland infection was performed to study the impact of a trypanosome infection on different aspects of the salivary gland functioning and the mechanisms that are induced in this tissue to tolerate the infection i.e. to control the negative impact of the parasite presence. Moreover, a transcriptome comparison with age-matched uninfected flies was done to see whether gene expression in the salivary glands is already affected by a trypanosome infection in the tsetse midgut. Results By a RNA-sequencing (RNA-seq) approach we compared the whole transcriptomes of flies with a T. brucei salivary gland/midgut infection versus flies with only a midgut infection or versus non-infected flies, all with the same age and feeding history. More than 7500 salivary gland transcripts were detected from which a core group of 1214 differentially expressed genes (768 up- and 446 down-regulated) were shared between the two transcriptional comparisons. Gene Ontology enrichment analysis and detailed gene expression comparisons showed a diverse impact at the gene transcript level. Increased expression was observed for transcripts encoding for proteins involved in immunity (like several genes of the Imd-signaling pathway, serine proteases, serpins and thioester-containing proteins), detoxification of reactive species, cell death, cytoskeleton organization, cell junction and repair. Decreased expression was observed for transcripts encoding the major secreted proteins such as 5′-nucleotidases, adenosine deaminases and the nucleic acid binding proteins Tsals. Moreover, expression of some gene categories in the salivary glands were found to be already affected by a trypanosome midgut infection, before the parasite reaches the salivary glands. Conclusions This study reveals that the T. brucei population in the tsetse salivary gland has a negative impact on its functioning and on the integrity of the gland epithelium. Our RNA-seq data suggest induction of a strong local tissue response in order to control the epithelial cell damage, the ROS intoxication of the cellular environment and the parasite infection, resulting in the fly tolerance to the infection. The modified expression of some gene categories in the tsetse salivary glands by a trypanosome infection at the midgut level indicate a putative anticipatory response in the salivary glands, before the parasite reaches this tissue. Electronic supplementary material The online version of this article (doi:10.1186/s12864-016-3283-0) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Irina Matetovici
- Unit of Veterinary Protozoology, Department of Biomedical Sciences, Institute of Tropical Medicine Antwerp (ITM), Antwerp, Belgium
| | - Guy Caljon
- Unit of Veterinary Protozoology, Department of Biomedical Sciences, Institute of Tropical Medicine Antwerp (ITM), Antwerp, Belgium.,Present address: Laboratory of Microbiology, Parasitology and Hygiene (LMPH), Department of Biomedical Sciences, University of Antwerp, Wilrijk, Belgium
| | - Jan Van Den Abbeele
- Unit of Veterinary Protozoology, Department of Biomedical Sciences, Institute of Tropical Medicine Antwerp (ITM), Antwerp, Belgium.
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19
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Bonfini A, Liu X, Buchon N. From pathogens to microbiota: How Drosophila intestinal stem cells react to gut microbes. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2016; 64:22-38. [PMID: 26855015 DOI: 10.1016/j.dci.2016.02.008] [Citation(s) in RCA: 65] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2015] [Revised: 02/03/2016] [Accepted: 02/04/2016] [Indexed: 06/05/2023]
Abstract
The intestine acts as one of the interfaces between an organism and its external environment. As the primary digestive organ, it is constantly exposed to a multitude of stresses as it processes and absorbs nutrients. Among these is the recurring damage induced by ingested pathogenic and commensal microorganisms. Both the bacterial activity and immune response itself can result in the loss of epithelial cells, which subsequently requires replacement. In the Drosophila midgut, this regenerative role is fulfilled by intestinal stem cells (ISCs). Microbes not only trigger cell loss and replacement, but also modify intestinal and whole organism physiology, thus modulating ISC activity. Regulation of ISCs is integrated through a complex network of signaling pathways initiated by other gut cell populations, including enterocytes, enteroblasts, enteroendocrine and visceral muscles cells. The gut also receives signals from circulating immune cells, the hemocytes, to properly respond against infection. This review summarizes the types of gut microbes found in Drosophila, mechanisms for their elimination, and provides an integrated view of the signaling pathways that regulate tissue renewal in the midgut.
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Affiliation(s)
| | - Xi Liu
- Department of Entomology, Cornell University, Ithaca, NY 14853, USA
| | - Nicolas Buchon
- Department of Entomology, Cornell University, Ithaca, NY 14853, USA.
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20
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Regna K, Kurshan PT, Harwood BN, Jenkins AM, Lai CQ, Muskavitch MAT, Kopin AS, Draper I. A critical role for the Drosophila dopamine D1-like receptor Dop1R2 at the onset of metamorphosis. BMC DEVELOPMENTAL BIOLOGY 2016; 16:15. [PMID: 27184815 PMCID: PMC4868058 DOI: 10.1186/s12861-016-0115-z] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/11/2015] [Accepted: 05/08/2016] [Indexed: 01/26/2023]
Abstract
BACKGROUND Insect metamorphosis relies on temporal and spatial cues that are precisely controlled. Previous studies in Drosophila have shown that untimely activation of genes that are essential to metamorphosis results in growth defects, developmental delay and death. Multiple factors exist that safeguard these genes against dysregulated expression. The list of identified negative regulators that play such a role in Drosophila development continues to expand. RESULTS By using RNAi transgene-induced gene silencing coupled to spatio/temporal assessment, we have unraveled an important role for the Drosophila dopamine 1-like receptor, Dop1R2, in development. We show that Dop1R2 knockdown leads to pre-adult lethality. In adults that escape death, abnormal wing expansion and/or melanization defects occur. Furthermore we show that salivary gland expression of this GPCR during the late larval/prepupal stage is essential for the flies to survive through adulthood. In addition to RNAi-induced effects, treatment of larvae with the high affinity D1-like receptor antagonist flupenthixol, also results in developmental arrest, and in morphological defects comparable to those seen in Dop1R2 RNAi flies. To examine the basis for pupal lethality in Dop1R2 RNAi flies, we carried out transcriptome analysis. These studies revealed up-regulation of genes that respond to ecdysone, regulate morphogenesis and/or modulate defense/immunity. CONCLUSION Taken together our findings suggest a role for Dop1R2 in the repression of genes that coordinate metamorphosis. Premature release of this inhibition is not tolerated by the developing fly.
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Affiliation(s)
- Kimberly Regna
- Department of Biology, Boston College, Chestnut Hill, MA, 02467, USA
| | - Peri T Kurshan
- Molecular Cardiology Research Institute, Tufts Medical Center, Boston, MA, 02111, USA.,Present Address: Department of Biology, Stanford University, California, 94305, USA
| | - Benjamin N Harwood
- Molecular Cardiology Research Institute, Tufts Medical Center, Boston, MA, 02111, USA
| | - Adam M Jenkins
- Department of Biology, Boston College, Chestnut Hill, MA, 02467, USA
| | - Chao-Qiang Lai
- Jean Mayer USDA Human Nutrition Research Center on Aging, Tufts University, Boston, MA, 02111, USA
| | - Marc A T Muskavitch
- Department of Biology, Boston College, Chestnut Hill, MA, 02467, USA.,Discovery Research, Biogen Idec, Cambridge, MA, 02142, USA
| | - Alan S Kopin
- Molecular Cardiology Research Institute, Tufts Medical Center, Boston, MA, 02111, USA
| | - Isabelle Draper
- Molecular Cardiology Research Institute, Tufts Medical Center, Boston, MA, 02111, USA.
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21
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Cytokine Diedel and a viral homologue suppress the IMD pathway in Drosophila. Proc Natl Acad Sci U S A 2016; 113:698-703. [PMID: 26739560 DOI: 10.1073/pnas.1516122113] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Viruses are obligatory intracellular parasites that suffer strong evolutionary pressure from the host immune system. Rapidly evolving viral genomes can adapt to this pressure by acquiring genes that counteract host defense mechanisms. For example, many vertebrate DNA viruses have hijacked cellular genes encoding cytokines or cytokine receptors to disrupt host cell communication. Insect viruses express suppressors of RNA interference or apoptosis, highlighting the importance of these cell intrinsic antiviral mechanisms in invertebrates. Here, we report the identification and characterization of a family of proteins encoded by insect DNA viruses that are homologous to a 12-kDa circulating protein encoded by the virus-induced Drosophila gene diedel (die). We show that die mutant flies have shortened lifespan and succumb more rapidly than controls when infected with Sindbis virus. This reduced viability is associated with deregulated activation of the immune deficiency (IMD) pathway of host defense and can be rescued by mutations in the genes encoding the homolog of IKKγ or IMD itself. Our results reveal an endogenous pathway that is exploited by insect viruses to modulate NF-κB signaling and promote fly survival during the antiviral response.
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22
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Ma X, Li X, Dong S, Xia Q, Wang F. A Fas associated factor negatively regulates anti-bacterial immunity by promoting Relish degradation in Bombyx mori. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2015; 63:144-151. [PMID: 26101847 DOI: 10.1016/j.ibmb.2015.06.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2015] [Revised: 06/15/2015] [Accepted: 06/18/2015] [Indexed: 06/04/2023]
Abstract
Negative regulation is required to keep NF-κB-dependent immune response under tight control. In previous study, we have identified a Fas associated factor (FAF) family member in Bombyx mori, BmFAF, and proposed it may act as a negative regulator in immune response. In this study, we found knock-down of BmFAF by RNAi led to a remarkable increase in transcriptional level of several antimicrobial peptide genes, including BmCecropinA1 and BmMoricin, and higher survival rate to Gram-negative bacterial infection. We also confirmed the regulatory role of BmFAF in suppressing NF-κB-dependent transcription by employing an inducible promoter in BmE cells. Consistent with these physiological phenotypes, BmFAF suppressed the activity of the essential transcription factor, Relish, in IMD signaling pathway by promoting its proteasomal degradation through direct interaction. In addition, by constructing various truncation mutants, we further demonstrated that UBA domain in BmFAF is required for the inhibitory role, and potential ubiquitination also occurs in this domain. Taken together, our results suggest that BmFAF is a negative regulator of IMD pathway by mediating degradation of Relish.
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Affiliation(s)
- Xiaojuan Ma
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing 400716, China
| | - Xianyang Li
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing 400716, China
| | - Shifeng Dong
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing 400716, China
| | - Qingyou Xia
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing 400716, China
| | - Fei Wang
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing 400716, China.
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23
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Cao X, He Y, Hu Y, Wang Y, Chen YR, Bryant B, Clem RJ, Schwartz LM, Blissard G, Jiang H. The immune signaling pathways of Manduca sexta. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2015; 62:64-74. [PMID: 25858029 PMCID: PMC4476939 DOI: 10.1016/j.ibmb.2015.03.006] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2015] [Revised: 03/16/2015] [Accepted: 03/17/2015] [Indexed: 05/10/2023]
Abstract
Signal transduction pathways and their coordination are critically important for proper functioning of animal immune systems. Our knowledge of the constituents of the intracellular signaling network in insects mainly comes from genetic analyses in Drosophila melanogaster. To facilitate future studies of similar systems in the tobacco hornworm and other lepidopteran insects, we have identified and examined the homologous genes in the genome of Manduca sexta. Based on 1:1 orthologous relationships in most cases, we hypothesize that the Toll, Imd, MAPK-JNK-p38 and JAK-STAT pathways are intact and operative in this species, as are most of the regulatory mechanisms. Similarly, cellular processes such as autophagy, apoptosis and RNA interference probably function in similar ways, because their mediators and modulators are mostly conserved in this lepidopteran species. We have annotated a total of 186 genes encoding 199 proteins, studied their domain structures and evolution, and examined their mRNA levels in tissues at different life stages. Such information provides a genomic perspective of the intricate signaling system in a non-drosophiline insect.
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Affiliation(s)
- Xiaolong Cao
- Department of Entomology and Plant Pathology, Oklahoma State University, Stillwater, OK 74078, USA
| | - Yan He
- Department of Entomology and Plant Pathology, Oklahoma State University, Stillwater, OK 74078, USA
| | - Yingxia Hu
- Department of Entomology and Plant Pathology, Oklahoma State University, Stillwater, OK 74078, USA
| | - Yang Wang
- Department of Entomology and Plant Pathology, Oklahoma State University, Stillwater, OK 74078, USA
| | - Yun-Ru Chen
- Boyce Thompson Institute, Cornell University, Ithaca, NY 14853, USA
| | - Bart Bryant
- Division of Biology, Kansas State University, Manhattan, KS 66506, USA
| | - Rollie J Clem
- Division of Biology, Kansas State University, Manhattan, KS 66506, USA
| | | | - Gary Blissard
- Boyce Thompson Institute, Cornell University, Ithaca, NY 14853, USA
| | - Haobo Jiang
- Department of Entomology and Plant Pathology, Oklahoma State University, Stillwater, OK 74078, USA.
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24
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Goto A, Fukuyama H, Imler JL, Hoffmann JA. The chromatin regulator DMAP1 modulates activity of the nuclear factor B (NF-B) transcription factor Relish in the Drosophila innate immune response. J Biol Chem 2015; 289:20470-6. [PMID: 24947515 DOI: 10.1074/jbc.c114.553719] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
The host defense of the model organism Drosophila is under the control of two major signaling cascades controlling transcription factors of the NF-B family, the Toll and the immune deficiency (IMD) pathways. The latter shares extensive similarities with the mammalian TNF-R pathway and was initially discovered for its role in anti-Gram-negative bacterial reactions. A previous interactome study from this laboratory reported that an unexpectedly large number of proteins are binding to the canonical components of the IMD pathway. Here, we focus on DNA methyltransferase-associated protein 1 (DMAP1), which this study identified as an interactant of Relish, a Drosophila transcription factor reminiscent of the mammalian p105 NF-B protein. We show that silencing of DMAP1 expression both in S2 cells and in flies results in a significant reduction of Escherichia coli-induced expression of antimicrobial peptides. Epistatic analysis indicates that DMAP1 acts in parallel or downstream of Relish. Co-immunoprecipitation experiments further reveal that, in addition to Relish, DMAP1 also interacts with Akirin and the Brahma-associated protein 55 kDa (BAP55). Taken together, these results reveal that DMAP1 is a novel nuclear modulator of the IMD pathway, possibly acting at the level of chromatin remodeling.
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25
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Gene discovery and differential expression analysis of humoral immune response elements in female Culicoides sonorensis (Diptera: Ceratopogonidae). Parasit Vectors 2014; 7:388. [PMID: 25145345 PMCID: PMC4158122 DOI: 10.1186/1756-3305-7-388] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2014] [Accepted: 08/01/2014] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Female Culicoides sonorensis midges (Diptera: Ceratopogonidae) are vectors of pathogens that impact livestock and wildlife in the United States. Little is known about their biology on a molecular-genetic level, including components of their immune system. Because the insect immune response is involved with important processes such as gut microbial homeostasis and vector competence, our aims were to identify components of the midge innate immune system and examine their expression profiles in response to diet across time. METHODS In our previous work, we de novo sequenced and analyzed the transcriptional landscape of female midges under several feeding states including teneral (unfed) and early and late time points after blood and sucrose. Here, those transcriptomes were further analyzed to identify insect innate immune orthologs, particularly humoral immune response elements. Additionally, we examined immune gene expression profiles in response to diet over time, on both a transcriptome-wide, whole-midge level and more specifically via qRTPCR analysis of antimicrobial peptide (AMP) expression in the alimentary canal. RESULTS We identified functional units comprising the immune deficiency (Imd), Toll and JAK/STAT pathways, including humoral factors, transmembrane receptors, signaling components, transcription factors/regulators and effectors such as AMPs. Feeding altered the expression of receptors, regulators, AMPs, prophenoloxidase and thioester-containing proteins, where blood had a greater effect than sucrose on the expression profiles of most innate immune components. qRTPCR of AMP genes showed that all five were significantly upregulated in the alimentary canal after blood feeding, possibly in response to proliferating populations of gut bacteria. CONCLUSIONS Identification and functional insight of humoral/innate immune components in female C. sonorensis updates our knowledge of the molecular biology of this important vector. Because diet alone influenced the expression of immune pathway components, including their effectors, subsequent study of the role of innate immunity in biological processes such as gut homeostasis and life history are being pursued. Furthermore, since the humoral response is a key contributor in gut immunity, manipulating immune gene expression will help in uncovering genetic components of vector competence, including midgut barriers to infection. The results of such studies will serve as a platform for designing novel transmission-blocking strategies.
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Kuraishi T, Hori A, Kurata S. Host-microbe interactions in the gut of Drosophila melanogaster. Front Physiol 2013; 4:375. [PMID: 24381562 PMCID: PMC3865371 DOI: 10.3389/fphys.2013.00375] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2013] [Accepted: 12/02/2013] [Indexed: 12/02/2022] Open
Abstract
Many insect species subsist on decaying and contaminated matter and are thus exposed to large quantities of microorganisms. To control beneficial commensals and combat infectious pathogens, insects must be armed with efficient systems for microbial recognition, signaling pathways, and effector molecules. The molecular mechanisms regulating these host-microbe interactions in insects have been largely clarified in Drosophila melanogaster with its powerful genetic and genomic tools. Here we review recent advances in this field, focusing mainly on the relationships between microbes and epithelial cells in the intestinal tract where the host exposure to the external environment is most frequent.
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Affiliation(s)
- Takayuki Kuraishi
- Department of Molrcular Biopharmacy and Genetics, Graduate School of Pharmaceutical Sciences, Tohoku University Sendai, Japan ; PRESTO, Japan Science and Technology Agency Tokyo, Japan
| | - Aki Hori
- Department of Molrcular Biopharmacy and Genetics, Graduate School of Pharmaceutical Sciences, Tohoku University Sendai, Japan
| | - Shoichiro Kurata
- Department of Molrcular Biopharmacy and Genetics, Graduate School of Pharmaceutical Sciences, Tohoku University Sendai, Japan
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Abstract
Intestinal homeostasis is achieved, in part, by the integration of a complex set of mechanisms that eliminate pathogens and tolerate the indigenous microbiota. Drosophila melanogaster feeds on microorganism-enriched matter and therefore has developed efficient mechanisms to control ingested microorganisms. Regulatory mechanisms ensure an appropriate level of immune reactivity in the gut to accommodate the presence of beneficial and dietary microorganisms, while allowing effective immune responses to clear pathogens. Maintenance of D. melanogaster gut homeostasis also involves regeneration of the intestine to repair damage associated with infection. Entomopathogenic bacteria have developed common strategies to subvert these defence mechanisms and kill their host.
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Gunaratna RT, Jiang H. A comprehensive analysis of the Manduca sexta immunotranscriptome. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2013; 39. [PMID: 23178408 PMCID: PMC3595354 DOI: 10.1016/j.dci.2012.10.004] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
As a biochemical model, Manduca sexta has substantially contributed to our knowledge on insect innate immunity. The RNA-Seq approach was implemented in three studies to examine tissue immunotranscriptomes of this species. With the latest and largest focusing on highly regulated process- and tissue-specific genes, we further analyzed the same set of data using BLAST2GO to explore functional aspects of the larval fat body (F) and hemocyte (H) transcriptomes with (I) or without (C) immune challenge. Using immunity-related sequences from other insects, we found 383 homologous contigs and compared them with those discovered based on relative abundance changes. The major overlap of the two lists validated our previous research designed for gene discovery and transcript profiling in organisms lacking sequenced genomes. By concatenating the contigs, we established a repertoire of 232 immunity-related genes encoding proteins for pathogen recognition (16%), signal transduction (53%), microbe killing (13%) and others (18%). We examined their transcript levels along with attribute classifications and detected prominent differences in nine of the 30 level 2 gene ontology (GO) categories. The increase in extracellular proteins (155%) was consistent with the highly induced synthesis of defense molecules (e.g., antimicrobial peptides) in fat body after the immune challenge. We identified most members of the putative Toll, IMD, MAPK-JNK-p38 and JAK-STAT pathways and small changes in their mRNA levels. Together, these findings set the stage for on-going analysis of the M. sexta immunogenome.
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Affiliation(s)
- Ramesh T Gunaratna
- Department of Entomology and Plant Pathology, Oklahoma State University, Stillwater, OK 74078, USA
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Merkling SH, van Rij RP. Beyond RNAi: antiviral defense strategies in Drosophila and mosquito. JOURNAL OF INSECT PHYSIOLOGY 2013; 59:159-170. [PMID: 22824741 DOI: 10.1016/j.jinsphys.2012.07.004] [Citation(s) in RCA: 97] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2012] [Revised: 07/11/2012] [Accepted: 07/12/2012] [Indexed: 06/01/2023]
Abstract
Virus transmission and spread by arthropods is a major economic and public health concern. The ongoing dissemination of arthropod-borne viruses by blood-feeding insects is an important incentive to study antiviral immunity in these animals. RNA interference is a major mechanism for antiviral defense in insects, including the fruit fly Drosophila melanogaster and several vector mosquitoes. However, recent data suggest that the evolutionary conserved Toll, Imd and Jak-Stat signaling pathways also contribute to antiviral immunity. Moreover, symbionts, such as the intracellular bacterium Wolbachia and the gut microflora, influence the course of virus infection in insects. These results add an additional level of complexity to antiviral immunity, but also provide novel opportunities to control the spread of arboviruses. In this review, we provide an overview of the current knowledge and recent developments in antiviral immunity in Dipteran insects, with a focus on non-RNAi mediated inducible responses.
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Affiliation(s)
- Sarah H Merkling
- Department of Medical Microbiology, Radboud University Nijmegen Medical Centre, Nijmegen Centre for Molecular Life Sciences, P.O. Box 9101, 6500 HB, Nijmegen, The Netherlands
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Charroux B, Royet J. Gut-microbiota interactions in non-mammals: What can we learn from Drosophila? Semin Immunol 2012; 24:17-24. [DOI: 10.1016/j.smim.2011.11.003] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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Royet J. Epithelial homeostasis and the underlying molecular mechanisms in the gut of the insect model Drosophila melanogaster. Cell Mol Life Sci 2011; 68:3651-60. [PMID: 21964927 PMCID: PMC11115164 DOI: 10.1007/s00018-011-0828-x] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2011] [Revised: 09/07/2011] [Accepted: 09/07/2011] [Indexed: 11/30/2022]
Abstract
Insects mostly develop on decaying and contaminated organic matter and often serve as vectors of biologically transmitted diseases by transporting microorganisms to the plant and animal hosts. As such, insects are constantly ingesting microorganisms, a small fraction of which reach their epithelial surfaces, mainly their digestive tract, where they can establish relationships ranging from symbiosis to mutualism or even parasitism. Understanding the tight physical, genetic, and biochemical interactions that takes place between intestinal epithelia and either resident or infectious microbes has been a long-lasting objective of the immunologist. Research in this field has recently been re-vitalized with the development of deep sequencing techniques, which allow qualitative and quantitative characterization of gut microbiota. Interestingly, the recent identification of regenerative stem cells in the Drosophila gut together with the initial characterization of Drosophila gut microbiota have opened up new avenues of study aimed at understanding the mechanisms that regulate the dialog between the Drosophila gut epithelium and its microbiota of this insect model. The fact that some of the responses are conserved across species combined with the power of Drosophila genetics could make this organism model a useful tool to further elucidate some aspects of the interaction occurring between the microbiota and the human gut.
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Affiliation(s)
- Julien Royet
- IBDML, UMR 6216 CNRS, Université Aix-Marseille, Marseille, France.
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