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Hajdú G, Szathmári C, Sőti C. Modeling Host-Pathogen Interactions in C. elegans: Lessons Learned from Pseudomonas aeruginosa Infection. Int J Mol Sci 2024; 25:7034. [PMID: 39000143 PMCID: PMC11241598 DOI: 10.3390/ijms25137034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2024] [Revised: 06/17/2024] [Accepted: 06/22/2024] [Indexed: 07/16/2024] Open
Abstract
Infections, such as that by the multiresistant opportunistic bacterial pathogen Pseudomonas aeruginosa, may pose a serious health risk, especially on vulnerable patient populations. The nematode Caenorhabditis elegans provides a simple organismal model to investigate both pathogenic mechanisms and the emerging role of innate immunity in host protection. Here, we review the virulence and infection strategies of P. aeruginosa and host defenses of C. elegans. We summarize the recognition mechanisms of patterns of pathogenesis, including novel pathogen-associated molecular patterns and surveillance immunity of translation, mitochondria, and lysosome-related organelles. We also review the regulation of antimicrobial and behavioral defenses by the worm's neuroendocrine system. We focus on how discoveries in this rich field align with well-characterized evolutionary conserved protective pathways, as well as on potential crossovers to human pathogenesis and innate immune responses.
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Affiliation(s)
- Gábor Hajdú
- Department of Molecular Biology, Semmelweis University, 1094 Budapest, Hungary
| | - Csenge Szathmári
- Department of Molecular Biology, Semmelweis University, 1094 Budapest, Hungary
| | - Csaba Sőti
- Department of Molecular Biology, Semmelweis University, 1094 Budapest, Hungary
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2
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Lee H, Boor SA, Hilbert ZA, Meisel JD, Park J, Wang Y, McKeown R, Fischer SEJ, Andersen EC, Kim DH. Genetic variants that modify neuroendocrine gene expression and foraging behavior of C. elegans. SCIENCE ADVANCES 2024; 10:eadk9481. [PMID: 38865452 PMCID: PMC11168454 DOI: 10.1126/sciadv.adk9481] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2023] [Accepted: 04/30/2024] [Indexed: 06/14/2024]
Abstract
The molecular mechanisms underlying diversity in animal behavior are not well understood. A major experimental challenge is determining the contribution of genetic variants that affect neuronal gene expression to differences in behavioral traits. In Caenorhabditis elegans, the neuroendocrine transforming growth factor-β ligand, DAF-7, regulates diverse behavioral responses to bacterial food and pathogens. The dynamic neuron-specific expression of daf-7 is modulated by environmental and endogenous bacteria-derived cues. Here, we investigated natural variation in the expression of daf-7 from the ASJ pair of chemosensory neurons. We identified common genetic variants in gap-2, encoding a Ras guanosine triphosphatase (GTPase)-activating protein homologous to mammalian synaptic Ras GTPase-activating protein, which modify daf-7 expression cell nonautonomously and promote exploratory foraging behavior in a partially DAF-7-dependent manner. Our data connect natural variation in neuron-specific gene expression to differences in behavior and suggest that genetic variation in neuroendocrine signaling pathways mediating host-microbe interactions may give rise to diversity in animal behavior.
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Affiliation(s)
- Harksun Lee
- Division of Infectious Diseases, Department of Pediatrics, Boston Children’s Hospital and Harvard Medical School, Boston, MA 02115, USA
| | - Sonia A. Boor
- Division of Infectious Diseases, Department of Pediatrics, Boston Children’s Hospital and Harvard Medical School, Boston, MA 02115, USA
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Zoë A. Hilbert
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Joshua D. Meisel
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Jaeseok Park
- Division of Infectious Diseases, Department of Pediatrics, Boston Children’s Hospital and Harvard Medical School, Boston, MA 02115, USA
| | - Ye Wang
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60208, USA
| | - Ryan McKeown
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60208, USA
| | - Sylvia E. J. Fischer
- Division of Infectious Diseases, Department of Pediatrics, Boston Children’s Hospital and Harvard Medical School, Boston, MA 02115, USA
- Harvard Medical School Initiative for RNA Medicine, Boston, MA 02115, USA
| | - Erik C. Andersen
- Department of Biology, Johns Hopkins University, Baltimore, MD 21212, USA
| | - Dennis H. Kim
- Division of Infectious Diseases, Department of Pediatrics, Boston Children’s Hospital and Harvard Medical School, Boston, MA 02115, USA
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3
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Gao B, Ruiz D, Case H, Jinkerson RE, Sun Q. Engineering bacterial warriors: harnessing microbes to modulate animal physiology. Curr Opin Biotechnol 2024; 87:103113. [PMID: 38564969 DOI: 10.1016/j.copbio.2024.103113] [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: 12/10/2023] [Revised: 02/21/2024] [Accepted: 03/04/2024] [Indexed: 04/04/2024]
Abstract
A central goal of synthetic biology is the reprogramming of living systems for predetermined biological functions. While many engineering efforts have been made in living systems, these innovations have been mainly employed with microorganisms or cell lines. The engineering of multicellular organisms including animals remains challenging owing to the complexity of these systems. In this context, microbes, with their intricate impact on animals, have opened new opportunities. Through the utilization of the symbiotic relationships between microbes and animals, researchers have effectively manipulated animals in various ways using engineered microbes. This focused approach has demonstrated its significance in scientific exploration and engineering with model animals, coral preservation and restoration, and advancements in human health.
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Affiliation(s)
- Baizhen Gao
- Department of Chemical Engineering, Texas A&M University, College Station, TX 77840, United States
| | - Daniela Ruiz
- Department of Chemical Engineering, Texas A&M University, College Station, TX 77840, United States; Program of Genetics and Genomics, Texas A&M University, College Station, TX 77840, United States
| | - Hayden Case
- Department of Biology, Texas A&M University, College Station, TX 77840, United States
| | - Robert E Jinkerson
- Department of Chemical and Environmental Engineering, University of California, Riverside, Riverside, CA 92521, United States; Department of Botany and Plant Sciences, University of California, Riverside, Riverside, CA 92521, United States
| | - Qing Sun
- Department of Chemical Engineering, Texas A&M University, College Station, TX 77840, United States; Program of Genetics and Genomics, Texas A&M University, College Station, TX 77840, United States.
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4
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Singh A, Luallen RJ. Understanding the factors regulating host-microbiome interactions using Caenorhabditis elegans. Philos Trans R Soc Lond B Biol Sci 2024; 379:20230059. [PMID: 38497260 PMCID: PMC10945399 DOI: 10.1098/rstb.2023.0059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Accepted: 01/01/2024] [Indexed: 03/19/2024] Open
Abstract
The Human Microbiome Project was a research programme that successfully identified associations between microbial species and healthy or diseased individuals. However, a major challenge identified was the absence of model systems for studying host-microbiome interactions, which would increase our capacity to uncover molecular interactions, understand organ-specificity and discover new microbiome-altering health interventions. Caenorhabditis elegans has been a pioneering model organism for over 70 years but was largely studied in the absence of a microbiome. Recently, ecological sampling of wild nematodes has uncovered a large amount of natural genetic diversity as well as a slew of associated microbiota. The field has now explored the interactions of C. elegans with its associated gut microbiome, a defined and non-random microbial community, highlighting its suitability for dissecting host-microbiome interactions. This core microbiome is being used to study the impact of host genetics, age and stressors on microbiome composition. Furthermore, single microbiome species are being used to dissect molecular interactions between microbes and the animal gut. Being amenable to health altering genetic and non-genetic interventions, C. elegans has emerged as a promising system to generate and test new hypotheses regarding host-microbiome interactions, with the potential to uncover novel paradigms relevant to other systems. This article is part of the theme issue 'Sculpting the microbiome: how host factors determine and respond to microbial colonization'.
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Affiliation(s)
- Anupama Singh
- Department of Biology, San Diego State University, San Diego, CA 92182, USA
| | - Robert J. Luallen
- Department of Biology, San Diego State University, San Diego, CA 92182, USA
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5
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Pei H, Lin Z, Yao K, Luo Y, Tong P, Chen H, Wu Y, Wu Z, Gao J. Ovalbumin promotes innate immune response of Caenorhabditis elegans through DAF-16 and SKN-1 pathways in insulin/IGF-1 signaling. J Physiol Biochem 2024:10.1007/s13105-024-01021-2. [PMID: 38632209 DOI: 10.1007/s13105-024-01021-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2023] [Accepted: 04/05/2024] [Indexed: 04/19/2024]
Abstract
Ovalbumin (OVA) is a major allergen in eggs and could induce severe allergic reactions in sensitive individuals, where the innate immune system works as a regulator. The mechanism of how innate immunity adjusts to food allergy is relatively well-studied, however, the effects of allergen uptake on the innate immune system remain unclear. Therefore, the Caenorhabditis elegans (C. elegans) model was utilized to assess the effects of OVA on its innate immune system. OVA enhanced the immune response of C. elegans with higher survival rates under Pseudomonas aeruginosa infection. Moreover, sustaining OVA treatment improved the health states that were reflected in the prolonged lifespan, alleviated oxidative stress, accelerated growth, and promoted motility. RNA-sequencing analysis and the slow-killing assays in the mutants of insulin/IGF-1 signaling (IIS)-related genes confirmed that IIS was necessary for OVA to regulate innate immunity. Besides, OVA activated SKN-1 temporarily and facilitated the nuclear localization of DAF-16 for improving immunity and health status in C. elegans. Together, OVA could enhance the innate immune responses via DAF-16 and SKN-1 pathways in the IIS of C. elegans, and this work will provide novel insights into the regulation of innate immunity by OVA in higher organisms.
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Affiliation(s)
- Haibing Pei
- State Key Laboratory of Food Science and Resources, Nanchang University, Nanchang, 330047, P.R. China
- College of Food Science & Technology, Nanchang University, Nanchang, 330047, P.R. China
- Jiangxi Province Key Laboratory of Food Allergy, Nanchang, 330047, P.R. China
| | - Zhiyin Lin
- State Key Laboratory of Food Science and Resources, Nanchang University, Nanchang, 330047, P.R. China
- College of Food Science & Technology, Nanchang University, Nanchang, 330047, P.R. China
- Jiangxi Province Key Laboratory of Food Allergy, Nanchang, 330047, P.R. China
| | - Kexin Yao
- State Key Laboratory of Food Science and Resources, Nanchang University, Nanchang, 330047, P.R. China
- College of Food Science & Technology, Nanchang University, Nanchang, 330047, P.R. China
- Jiangxi Province Key Laboratory of Food Allergy, Nanchang, 330047, P.R. China
| | - Yeqing Luo
- State Key Laboratory of Food Science and Resources, Nanchang University, Nanchang, 330047, P.R. China
- College of Food Science & Technology, Nanchang University, Nanchang, 330047, P.R. China
- Jiangxi Province Key Laboratory of Food Allergy, Nanchang, 330047, P.R. China
| | - Ping Tong
- State Key Laboratory of Food Science and Resources, Nanchang University, Nanchang, 330047, P.R. China.
- Jiangxi Province Key Laboratory of Food Allergy, Nanchang, 330047, P.R. China.
| | - Hongbing Chen
- State Key Laboratory of Food Science and Resources, Nanchang University, Nanchang, 330047, P.R. China
- Jiangxi Province Key Laboratory of Food Allergy, Nanchang, 330047, P.R. China
- Sino-German Joint Research Institute, Nanchang University, Nanchang, 330047, P.R. China
| | - Yong Wu
- State Key Laboratory of Food Science and Resources, Nanchang University, Nanchang, 330047, P.R. China
- Jiangxi Province Key Laboratory of Food Allergy, Nanchang, 330047, P.R. China
- Sino-German Joint Research Institute, Nanchang University, Nanchang, 330047, P.R. China
| | - Zhihua Wu
- State Key Laboratory of Food Science and Resources, Nanchang University, Nanchang, 330047, P.R. China
- Jiangxi Province Key Laboratory of Food Allergy, Nanchang, 330047, P.R. China
- Sino-German Joint Research Institute, Nanchang University, Nanchang, 330047, P.R. China
| | - Jinyan Gao
- College of Food Science & Technology, Nanchang University, Nanchang, 330047, P.R. China.
- Jiangxi Province Key Laboratory of Food Allergy, Nanchang, 330047, P.R. China.
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6
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Pradeu T, Thomma BPHJ, Girardin SE, Lemaitre B. The conceptual foundations of innate immunity: Taking stock 30 years later. Immunity 2024; 57:613-631. [PMID: 38599162 DOI: 10.1016/j.immuni.2024.03.007] [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: 01/14/2024] [Revised: 02/23/2024] [Accepted: 03/06/2024] [Indexed: 04/12/2024]
Abstract
While largely neglected over decades during which adaptive immunity captured most of the attention, innate immune mechanisms have now become central to our understanding of immunology. Innate immunity provides the first barrier to infection in vertebrates, and it is the sole mechanism of host defense in invertebrates and plants. Innate immunity also plays a critical role in maintaining homeostasis, shaping the microbiota, and in disease contexts such as cancer, neurodegeneration, metabolic syndromes, and aging. The emergence of the field of innate immunity has led to an expanded view of the immune system, which is no longer restricted to vertebrates and instead concerns all metazoans, plants, and even prokaryotes. The study of innate immunity has given rise to new concepts and language. Here, we review the history and definition of the core concepts of innate immunity, discussing their value and fruitfulness in the long run.
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Affiliation(s)
- Thomas Pradeu
- CNRS UMR 5164 ImmunoConcept, University of Bordeaux, Bordeaux, France; Department of Biological and Medical Sciences, University of Bordeaux, Bordeaux, France; Presidential Fellow, Chapman University, Orange, CA, USA.
| | - Bart P H J Thomma
- Institute for Plant Sciences, University of Cologne, Cologne, Germany
| | - Stephen E Girardin
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Bruno Lemaitre
- Global Health Institute, School of Life Science, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland.
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7
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Awe T, Fasawe A, Sawe C, Ogunware A, Jamiu AT, Allen M. The modulatory role of gut microbiota on host behavior: exploring the interaction between the brain-gut axis and the neuroendocrine system. AIMS Neurosci 2024; 11:49-62. [PMID: 38617041 PMCID: PMC11007408 DOI: 10.3934/neuroscience.2024004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2023] [Revised: 03/26/2024] [Accepted: 03/28/2024] [Indexed: 04/16/2024] Open
Abstract
The brain-gut axis refers to the communication between the central nervous system and the gastrointestinal tract, with the gut microbiome playing a crucial role. While our understanding of the interaction between the gut microbiome and the host's physiology is still in its nascent stage, evidence suggests that the gut microbiota can indeed modulate host behavior. Understanding the specific mechanisms by which the gut microbiota community modulates the host's behavior remains the focus of present and future neuro-gastroenterology studies. This paper reviews several pieces of evidence from the literature on the impact of gut microbiota on host behavior across animal taxa. We explore the different pathways through which this modulation occurs, with the aim of deepening our understanding of the fascinating relationship between the gut microbiome and the central nervous system.
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Affiliation(s)
- Temitope Awe
- Department of Cell Biology and Genetics, University of Lagos, Lagos, Nigeria
- School of Biological Sciences, Illinois State University, Normal, IL, USA
| | - Ayoola Fasawe
- School of Biological Sciences, Illinois State University, Normal, IL, USA
| | - Caleb Sawe
- School of Biological Sciences, Illinois State University, Normal, IL, USA
| | - Adedayo Ogunware
- Department of Neuroscience, Developmental and Regenerative Biology, University of Texas at San Antonio, San Antonio, TX, USA
| | | | - Michael Allen
- Department of Physiology, College of Medicine, Lagos State University, Lagos, Nigeria
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8
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Kulalert W, Wells AC, Link VM, Lim AI, Bouladoux N, Nagai M, Harrison OJ, Kamenyeva O, Kabat J, Enamorado M, Chiu IM, Belkaid Y. The neuroimmune CGRP-RAMP1 axis tunes cutaneous adaptive immunity to the microbiota. Proc Natl Acad Sci U S A 2024; 121:e2322574121. [PMID: 38451947 PMCID: PMC10945812 DOI: 10.1073/pnas.2322574121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2023] [Accepted: 01/22/2024] [Indexed: 03/09/2024] Open
Abstract
The somatosensory nervous system surveils external stimuli at barrier tissues, regulating innate immune cells under infection and inflammation. The roles of sensory neurons in controlling the adaptive immune system, and more specifically immunity to the microbiota, however, remain elusive. Here, we identified a mechanism for direct neuroimmune communication between commensal-specific T lymphocytes and somatosensory neurons mediated by the neuropeptide calcitonin gene-related peptide (CGRP) in the skin. Intravital imaging revealed that commensal-specific T cells are in close proximity to cutaneous nerve fibers in vivo. Correspondingly, we observed upregulation of the receptor for the neuropeptide CGRP, RAMP1, in CD8+ T lymphocytes induced by skin commensal colonization. The neuroimmune CGRP-RAMP1 signaling axis functions in commensal-specific T cells to constrain Type 17 responses and moderate the activation status of microbiota-reactive lymphocytes at homeostasis. As such, modulation of neuroimmune CGRP-RAMP1 signaling in commensal-specific T cells shapes the overall activation status of the skin epithelium, thereby impacting the outcome of responses to insults such as wounding. The ability of somatosensory neurons to control adaptive immunity to the microbiota via the CGRP-RAMP1 axis underscores the various layers of regulation and multisystem coordination required for optimal microbiota-reactive T cell functions under steady state and pathology.
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Affiliation(s)
- Warakorn Kulalert
- Metaorganism Immunity Section, Laboratory of Host Immunity and Microbiome, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, MD20892
| | - Alexandria C. Wells
- Metaorganism Immunity Section, Laboratory of Host Immunity and Microbiome, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, MD20892
| | - Verena M. Link
- Metaorganism Immunity Section, Laboratory of Host Immunity and Microbiome, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, MD20892
| | - Ai Ing Lim
- Metaorganism Immunity Section, Laboratory of Host Immunity and Microbiome, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, MD20892
| | - Nicolas Bouladoux
- Metaorganism Immunity Section, Laboratory of Host Immunity and Microbiome, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, MD20892
- National Institute of Allergy and Infectious Diseases Microbiome Program, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, MD20892
| | - Motoyoshi Nagai
- Metaorganism Immunity Section, Laboratory of Host Immunity and Microbiome, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, MD20892
| | - Oliver J. Harrison
- Metaorganism Immunity Section, Laboratory of Host Immunity and Microbiome, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, MD20892
| | - Olena Kamenyeva
- Biological Imaging Section, Research Technology Branch, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, MD20892
| | - Juraj Kabat
- Biological Imaging Section, Research Technology Branch, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, MD20892
| | - Michel Enamorado
- Metaorganism Immunity Section, Laboratory of Host Immunity and Microbiome, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, MD20892
- Kimberly and Eric J. Waldman Department of Dermatology, Mark Lebwohl Center for Neuroinflammation and Sensation, Marc and Jennifer Lipschultz Precision Immunology Institute, and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY10029
| | - Isaac M. Chiu
- Department of Immunology, Harvard Medical School, Boston, MA02115
| | - Yasmine Belkaid
- Metaorganism Immunity Section, Laboratory of Host Immunity and Microbiome, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, MD20892
- National Institute of Allergy and Infectious Diseases Microbiome Program, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, MD20892
- Unite Metaorganisme, Immunology Department, Pasteur Institute, 75015 Paris, France
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9
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Fox BW, Helf MJ, Burkhardt RN, Artyukhin AB, Curtis BJ, Palomino DF, Schroeder AF, Chaturbedi A, Tauffenberger A, Wrobel CJJ, Zhang YK, Lee SS, Schroeder FC. Evolutionarily related host and microbial pathways regulate fat desaturation in C. elegans. Nat Commun 2024; 15:1520. [PMID: 38374083 PMCID: PMC10876521 DOI: 10.1038/s41467-024-45782-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2023] [Accepted: 01/31/2024] [Indexed: 02/21/2024] Open
Abstract
Fatty acid desaturation is central to metazoan lipid metabolism and provides building blocks of membrane lipids and precursors of diverse signaling molecules. Nutritional conditions and associated microbiota regulate desaturase expression, but the underlying mechanisms have remained unclear. Here, we show that endogenous and microbiota-dependent small molecule signals promote lipid desaturation via the nuclear receptor NHR-49/PPARα in C. elegans. Untargeted metabolomics of a β-oxidation mutant, acdh-11, in which expression of the stearoyl-CoA desaturase FAT-7/SCD1 is constitutively increased, revealed accumulation of a β-cyclopropyl fatty acid, becyp#1, that potently activates fat-7 expression via NHR-49. Biosynthesis of becyp#1 is strictly dependent on expression of cyclopropane synthase by associated bacteria, e.g., E. coli. Screening for structurally related endogenous metabolites revealed a β-methyl fatty acid, bemeth#1, which mimics the activity of microbiota-dependent becyp#1 but is derived from a methyltransferase, fcmt-1, that is conserved across Nematoda and likely originates from bacterial cyclopropane synthase via ancient horizontal gene transfer. Activation of fat-7 expression by these structurally similar metabolites is controlled by distinct mechanisms, as microbiota-dependent becyp#1 is metabolized by a dedicated β-oxidation pathway, while the endogenous bemeth#1 is metabolized via α-oxidation. Collectively, we demonstrate that evolutionarily related biosynthetic pathways in metazoan host and associated microbiota converge on NHR-49/PPARα to regulate fat desaturation.
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Affiliation(s)
- Bennett W Fox
- Boyce Thompson Institute and Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY, 14853, USA
| | - Maximilian J Helf
- Boyce Thompson Institute and Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY, 14853, USA
| | - Russell N Burkhardt
- Boyce Thompson Institute and Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY, 14853, USA
| | - Alexander B Artyukhin
- Chemistry Department, College of Environmental Science and Forestry, State University of New York, Syracuse, NY, 13210, USA
| | - Brian J Curtis
- Boyce Thompson Institute and Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY, 14853, USA
| | - Diana Fajardo Palomino
- Boyce Thompson Institute and Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY, 14853, USA
| | - Allen F Schroeder
- Boyce Thompson Institute and Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY, 14853, USA
| | - Amaresh Chaturbedi
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY, 14853, USA
| | - Arnaud Tauffenberger
- Boyce Thompson Institute and Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY, 14853, USA
| | - Chester J J Wrobel
- Boyce Thompson Institute and Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY, 14853, USA
| | - Ying K Zhang
- Boyce Thompson Institute and Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY, 14853, USA
| | - Siu Sylvia Lee
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY, 14853, USA
| | - Frank C Schroeder
- Boyce Thompson Institute and Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY, 14853, USA.
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10
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Boor SA, Meisel JD, Kim DH. Neuroendocrine gene expression coupling of interoceptive bacterial food cues to foraging behavior of C. elegans. eLife 2024; 12:RP91120. [PMID: 38231572 PMCID: PMC10945577 DOI: 10.7554/elife.91120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2024] Open
Abstract
Animal internal state is modulated by nutrient intake, resulting in behavioral responses to changing food conditions. The neural mechanisms by which internal states are generated and maintained are not well understood. Here, we show that in the nematode Caenorhabditis elegans, distinct cues from bacterial food - interoceptive signals from the ingestion of bacteria and gustatory molecules sensed from nearby bacteria - act antagonistically on the expression of the neuroendocrine TGF-beta ligand DAF-7 from the ASJ pair of sensory neurons to modulate foraging behavior. A positive-feedback loop dependent on the expression of daf-7 from the ASJ neurons acts to promote transitions between roaming and dwelling foraging states and influence the persistence of roaming states. SCD-2, the C. elegans ortholog of mammalian anaplastic lymphoma kinase (ALK), which has been implicated in the central control of metabolism of mammals, functions in the AIA interneurons to regulate foraging behavior and cell-non-autonomously control the expression of DAF-7 from the ASJ neurons. Our data establish how a dynamic neuroendocrine daf-7 expression feedback loop regulated by SCD-2 functions to couple sensing and ingestion of bacterial food to foraging behavior. We further suggest that this neuroendocrine feedback loop underlies previously characterized exploratory behaviors in C. elegans. Our data suggest that the expression of daf-7 from the ASJ neurons contributes to and is correlated with an internal state of 'unmet need' that regulates exploratory foraging behavior in response to bacterial cues in diverse physiological contexts.
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Affiliation(s)
- Sonia A Boor
- Division of Infectious Diseases, Department of Pediatrics, Boston Children’s Hospital and Harvard Medical SchoolBostonUnited States
- Department of Biology, Massachusetts Institute of TechnologyCambridgeUnited States
| | - Joshua D Meisel
- Department of Biology, Massachusetts Institute of TechnologyCambridgeUnited States
- Department of Molecular Biology, Massachusetts General HospitalBostonUnited States
| | - Dennis H Kim
- Division of Infectious Diseases, Department of Pediatrics, Boston Children’s Hospital and Harvard Medical SchoolBostonUnited States
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11
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Chai VZ, Farajzadeh T, Meng Y, Lo SB, Asaed TA, Taylor CJ, Glater EE. Chemical basis of microbiome preference in the nematode C. elegans. Sci Rep 2024; 14:1350. [PMID: 38228683 PMCID: PMC10791660 DOI: 10.1038/s41598-024-51533-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2023] [Accepted: 01/06/2024] [Indexed: 01/18/2024] Open
Abstract
Animals are exposed to many microbes in their environment, some of which have been shown to colonize various tissues including the intestine. The composition of the intestinal microbiota affects many aspects of the host's physiology and health. Despite this, very little is known about whether host behavior contributes to the colonization. We approach this question in the nematode C. elegans, which feeds on bacteria and also harbors an intestinal microbiome. We examined the behavior of C. elegans towards CeMbio, a simplified microbiome consisting of twelve strains that represent the bacteria found in the animal's natural environment. We observed that C. elegans raised on E. coli shows a strong preference for three members of CeMbio (Lelliottia amnigena JUb66, Enterobacter hormaechei CEent1, and Pantoea nemavictus BIGb0393) compared to E. coli. Previously, these three bacterial strains have been shown to support faster C. elegans development time than E. coli OP50 and are low colonizers compared to eight other members of CeMbio. We then used gas chromatography coupled to mass spectrometry to identify that these three bacteria release isoamyl alcohol, a previously described C. elegans chemoattractant. We suggest that C. elegans seeks bacteria that release isoamyl alcohol and support faster growth.
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Affiliation(s)
- Victor Z Chai
- Department of Neuroscience, Pomona College, Claremont, CA, USA
| | | | - Yufei Meng
- Department of Neuroscience, Pomona College, Claremont, CA, USA
| | - Sokhna B Lo
- Department of Neuroscience, Pomona College, Claremont, CA, USA
| | - Tymmaa A Asaed
- Department of Neuroscience, Pomona College, Claremont, CA, USA
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12
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Bollen DP, Reddy KC, Lascarez-Lagunas LI, Kim DH, Colaiácovo MP. Germline mitotic quiescence and cell death are induced in Caenorhabditis elegans by exposure to pathogenic Pseudomonas aeruginosa. Genetics 2024; 226:iyad197. [PMID: 37956057 PMCID: PMC10763535 DOI: 10.1093/genetics/iyad197] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2023] [Revised: 08/08/2023] [Accepted: 11/03/2023] [Indexed: 11/15/2023] Open
Abstract
The impact of exposure to microbial pathogens on animal reproductive capacity and germline physiology is not well understood. The nematode Caenorhabditis elegans is a bacterivore that encounters pathogenic microbes in its natural environment. How pathogenic bacteria affect host reproductive capacity of C. elegans is not well understood. Here, we show that exposure of C. elegans hermaphrodites to the Gram-negative pathogen Pseudomonas aeruginosa causes a marked reduction in brood size with concomitant reduction in the number of nuclei in the germline and gonad size. We define 2 processes that are induced that contribute to the decrease in the number of germ cell nuclei. First, we observe that infection with P. aeruginosa leads to the induction of germ cell apoptosis. Second, we observe that this exposure induces mitotic quiescence in the proliferative zone of the C. elegans gonad. Importantly, these processes appear to be reversible; when animals are removed from the presence of P. aeruginosa, germ cell apoptosis is abated, germ cell nuclei numbers increase, and brood sizes recover. The reversible germline dynamics during exposure to P. aeruginosa may represent an adaptive response to improve survival of progeny and may serve to facilitate resource allocation that promotes survival during pathogen infection.
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Affiliation(s)
- Daniel P Bollen
- Division of Infectious Diseases and Department of Pediatrics, Boston Children's Hospital and Harvard Medical School, Boston, MA 02115, USA
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Kirthi C Reddy
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
- Molecular Neurobiology Laboratory, The Salk Institute for Biological Studies, La Jolla, CA 92037, USA
| | | | - Dennis H Kim
- Division of Infectious Diseases and Department of Pediatrics, Boston Children's Hospital and Harvard Medical School, Boston, MA 02115, USA
| | - Monica P Colaiácovo
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA
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13
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Purice MD, Severs LJ, Singhvi A. Glia in Invertebrate Models: Insights from Caenorhabditis elegans. ADVANCES IN NEUROBIOLOGY 2024; 39:19-49. [PMID: 39190070 DOI: 10.1007/978-3-031-64839-7_2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/28/2024]
Abstract
Glial cells modulate brain development, function, and health across all bilaterian animals, and studies in the past two decades have made rapid strides to uncover the underlying molecular mechanisms of glial functions. The nervous system of the invertebrate genetic model Caenorhabditis elegans (C. elegans) has small cell numbers with invariant lineages, mapped connectome, easy genetic manipulation, and a short lifespan, and the animal is also optically transparent. These characteristics are revealing C. elegans to be a powerful experimental platform for studying glial biology. This chapter discusses studies in C. elegans that add to our understanding of how glia modulate adult neural functions, and thereby animal behaviors, as well as emerging evidence of their roles as autonomous sensory cells. The rapid molecular and cellular advancements in understanding C. elegans glia in recent years underscore the utility of this model in studies of glial biology. We conclude with a perspective on future research avenues for C. elegans glia that may readily contribute molecular mechanistic insights into glial functions in the nervous system.
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Affiliation(s)
- Maria D Purice
- Division of Basic Sciences, Fred Hutchinson Cancer Center, Seattle, WA, USA
| | - Liza J Severs
- Division of Basic Sciences, Fred Hutchinson Cancer Center, Seattle, WA, USA
| | - Aakanksha Singhvi
- Division of Basic Sciences, Fred Hutchinson Cancer Center, Seattle, WA, USA.
- Department of Biological Structure, University of Washington School of Medicine, Seattle, WA, USA.
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14
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Moradian H, Gabriel T, Barrau M, Roblin X, Paul S. New methods to unveil host-microbe interaction mechanisms along the microbiota-gut-brain-axis. Gut Microbes 2024; 16:2351520. [PMID: 38717832 PMCID: PMC11086032 DOI: 10.1080/19490976.2024.2351520] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/20/2023] [Accepted: 05/01/2024] [Indexed: 05/12/2024] Open
Abstract
Links between the gut microbiota and human health have been supported throughout numerous studies, such as the development of neurological disease disorders. This link is referred to as the "microbiota-gut-brain axis" and is the focus of an emerging field of research. Microbial-derived metabolites and gut and neuro-immunological metabolites regulate this axis in health and many diseases. Indeed, assessing these signals, whether induced by microbial metabolites or neuro-immune mediators, could significantly increase our knowledge of the microbiota-gut-brain axis. However, this will require the development of appropriate techniques and potential models. Methods for studying the induced signals originating from the microbiota remain crucial in this field. This review discusses the methods and techniques available for studies of microbiota-gut-brain interactions. We highlight several much-debated elements of these methodologies, including the widely used in vivo and in vitro models, their implications, and perspectives in the field based on a systematic review of PubMed. Applications of various animal models (zebrafish, mouse, canine, rat, rabbit) to microbiota-gut-brain axis research with practical examples of in vitro methods and innovative approaches to studying gut-brain communications are highlighted. In particular, we extensively discuss the potential of "organ-on-a-chip" devices and their applications in this field. Overall, this review sheds light on the most widely used models and methods, guiding researchers in the rational choice of strategies for studies of microbiota-gut-brain interactions.
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Affiliation(s)
- Habibullah Moradian
- CIRI – Centre International de Recherche en Infectiologie, Team GIMAP, Univ Lyon, Université Claude Bernard Lyon 1, Saint-Etienne, France
| | - Tristan Gabriel
- CIRI – Centre International de Recherche en Infectiologie, Team GIMAP, Univ Lyon, Université Claude Bernard Lyon 1, Saint-Etienne, France
| | - Mathilde Barrau
- CIRI – Centre International de Recherche en Infectiologie, Team GIMAP, Univ Lyon, Université Claude Bernard Lyon 1, Saint-Etienne, France
- CIC 1408 Inserm Vaccinology, University Hospital of Saint-Etienne, Saint-Etienne, France
| | - Xavier Roblin
- CIRI – Centre International de Recherche en Infectiologie, Team GIMAP, Univ Lyon, Université Claude Bernard Lyon 1, Saint-Etienne, France
- CIC 1408 Inserm Vaccinology, University Hospital of Saint-Etienne, Saint-Etienne, France
| | - Stéphane Paul
- CIRI – Centre International de Recherche en Infectiologie, Team GIMAP, Univ Lyon, Université Claude Bernard Lyon 1, Saint-Etienne, France
- CIC 1408 Inserm Vaccinology, University Hospital of Saint-Etienne, Saint-Etienne, France
- Immunology Department, University Hospital of Saint-Etienne, Saint-Etienne, France
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15
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Kulalert W, Wells AC, Link VM, Lim AI, Bouladoux N, Nagai M, Harrison OJ, Kamenyeva O, Kabat J, Enamorado M, Chiu IM, Belkaid Y. The neuroimmune CGRP-RAMP1 axis tunes cutaneous adaptive immunity to the microbiota. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.26.573358. [PMID: 38234748 PMCID: PMC10793430 DOI: 10.1101/2023.12.26.573358] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2024]
Abstract
The somatosensory nervous system surveils external stimuli at barrier tissues, regulating innate immune cells under infection and inflammation. The roles of sensory neurons in controlling the adaptive immune system, and more specifically immunity to the microbiota, however, remain elusive. Here, we identified a novel mechanism for direct neuroimmune communication between commensal-specific T lymphocytes and somatosensory neurons mediated by the neuropeptide Calcitonin Gene-Related Peptide (CGRP) in the skin. Intravital imaging revealed that commensal-specific T cells are in close proximity to cutaneous nerve fibers in vivo . Correspondingly, we observed upregulation of the receptor for the neuropeptide CGRP, RAMP1, in CD8 + T lymphocytes induced by skin commensal colonization. Neuroimmune CGRP-RAMP1 signaling axis functions in commensal-specific T cells to constrain Type 17 responses and moderate the activation status of microbiota-reactive lymphocytes at homeostasis. As such, modulation of neuroimmune CGRP-RAMP1 signaling in commensal-specific T cells shapes the overall activation status of the skin epithelium, thereby impacting the outcome of responses to insults such as wounding. The ability of somatosensory neurons to control adaptive immunity to the microbiota via the CGRP-RAMP1 axis underscores the various layers of regulation and multisystem coordination required for optimal microbiota-reactive T cell functions under steady state and pathology. Significance statement Multisystem coordination at barrier surfaces is critical for optimal tissue functions and integrity, in response to microbial and environmental cues. In this study, we identified a novel neuroimmune crosstalk mechanism between the sensory nervous system and the adaptive immune response to the microbiota, mediated by the neuropeptide CGRP and its receptor RAMP1 on skin microbiota-induced T lymphocytes. The neuroimmune CGPR-RAMP1 axis constrains adaptive immunity to the microbiota and overall limits the activation status of the skin epithelium, impacting tissue responses to wounding. Our study opens the door to a new avenue to modulate adaptive immunity to the microbiota utilizing neuromodulators, allowing for a more integrative and tailored approach to harnessing microbiota-induced T cells to promote barrier tissue protection and repair.
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Boor SA, Meisel JD, Kim DH. Neuroendocrine Gene Expression Coupling of Interoceptive Bacterial Food Cues to Foraging Behavior of C. elegans. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.15.549072. [PMID: 37503081 PMCID: PMC10369937 DOI: 10.1101/2023.07.15.549072] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/29/2023]
Abstract
Animal internal state is modulated by nutrient intake, resulting in behavioral responses to changing food conditions. The neural mechanisms by which internal states are generated and maintained are not well understood. Here, we show that in the nematode Caenorhabditis elegans, distinct cues from bacterial food - interoceptive signals from the ingestion of bacteria and gustatory molecules sensed from nearby bacteria - act antagonistically on the expression of the neuroendocrine TGF-beta ligand DAF-7 from the ASJ pair of sensory neurons to modulate foraging behavior. A positive-feedback loop dependent on the expression of daf-7 from the ASJ neurons acts to promote transitions between roaming and dwelling foraging states and influence the persistence of roaming states. SCD-2, the C. elegans ortholog of mammalian Anaplastic Lymphoma Kinase (ALK), which has been implicated in the central control of metabolism of mammals, functions in the AIA interneurons to regulate foraging behavior and cell-non-autonomously control the expression of DAF-7 from the ASJ neurons. Our data establish how a dynamic neuroendocrine daf-7 expression feedback loop regulated by SCD-2 functions to couple sensing and ingestion of bacterial food to foraging behavior. We further suggest that this neuroendocrine feedback loop underlies previously characterized exploratory behaviors in C. elegans. Our data suggest that the expression of daf-7 from the ASJ neurons contributes to and is correlated with an internal state of "unmet need" that regulates exploratory foraging behavior in response to bacterial cues in diverse physiological contexts.
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Affiliation(s)
- Sonia A. Boor
- Division of Infectious Diseases, Department of Pediatrics, Boston Children’s Hospital and Harvard Medical School, Boston, MA 02115
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139
| | - Joshua D. Meisel
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114
| | - Dennis H. Kim
- Division of Infectious Diseases, Department of Pediatrics, Boston Children’s Hospital and Harvard Medical School, Boston, MA 02115
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17
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Bechtel W, Bich L. Using neurons to maintain autonomy: Learning from C. elegans. Biosystems 2023; 232:105017. [PMID: 37666409 DOI: 10.1016/j.biosystems.2023.105017] [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: 07/21/2023] [Revised: 08/29/2023] [Accepted: 08/29/2023] [Indexed: 09/06/2023]
Abstract
Understanding how biological organisms are autonomous-maintain themselves far from equilibrium through their own activities-requires understanding how they regulate those activities. In multicellular animals, such control can be exercised either via endocrine signaling through the vasculature or via neurons. In C. elegans this control is exercised by a well-delineated relatively small but distributed nervous system that relies on both chemical and electric transmission of signals. This system provides resources to integrate information from multiple sources as needed to maintain the organism. Especially important for the exercise of neural control are neuromodulators, which we present as setting agendas for control through more traditional electrical signaling. To illustrate how the C. elegans nervous system integrates multiple sources of information in controlling activities important for autonomy, we focus on feeding behavior and responses to adverse conditions. We conclude by considering how a distributed nervous system without a centralized controller is nonetheless adequate for autonomy.
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Affiliation(s)
- William Bechtel
- Department of Philosophy; University of California, San Diego; La Jolla, CA 92093-0119, USA.
| | - Leonardo Bich
- IAS-Research Centre for Life, Mind and Society; Department of Philosophy; University of the Basque Country (UPV/EHU); Avenida de Tolosa 70; Donostia-San Sebastian, 20018; Spain.
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18
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Lee H, Boor SA, Hilbert ZA, Meisel JD, Park J, Wang Y, McKeown R, Fischer SEJ, Andersen EC, Kim DH. Genetic Variants That Modify the Neuroendocrine Regulation of Foraging Behavior in C. elegans. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.09.556976. [PMID: 37745484 PMCID: PMC10515746 DOI: 10.1101/2023.09.09.556976] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/26/2023]
Abstract
The molecular mechanisms underlying diversity in animal behavior are not well understood. A major experimental challenge is determining the contribution of genetic variants that affect neuronal gene expression to differences in behavioral traits. The neuroendocrine TGF-beta ligand, DAF-7, regulates diverse behavioral responses of Caenorhabditis elegans to bacterial food and pathogens. The dynamic neuron-specific expression of daf-7 is modulated by environmental and endogenous bacteria-derived cues. Here, we investigated natural variation in the expression of daf-7 from the ASJ pair of chemosensory neurons and identified common variants in gap-2, encoding a GTPase-Activating Protein homologous to mammalian SynGAP proteins, which modify daf-7 expression cell-non-autonomously and promote exploratory foraging behavior in a DAF-7-dependent manner. Our data connect natural variation in neuron-specific gene expression to differences in behavior and suggest that genetic variation in neuroendocrine signaling pathways mediating host-microbe interactions may give rise to diversity in animal behavior.
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Affiliation(s)
- Harksun Lee
- Division of Infectious Diseases, Department of Pediatrics, Boston Children’s Hospital and Harvard Medical School; Boston, 02115, USA
| | - Sonia A. Boor
- Division of Infectious Diseases, Department of Pediatrics, Boston Children’s Hospital and Harvard Medical School; Boston, 02115, USA
- Department of Biology, Massachusetts Institute of Technology; Cambridge, 02139, USA
| | - Zoë A. Hilbert
- Department of Biology, Massachusetts Institute of Technology; Cambridge, 02139, USA
| | - Joshua D. Meisel
- Department of Biology, Massachusetts Institute of Technology; Cambridge, 02139, USA
| | - Jaeseok Park
- Division of Infectious Diseases, Department of Pediatrics, Boston Children’s Hospital and Harvard Medical School; Boston, 02115, USA
| | - Ye Wang
- Department of Molecular Biosciences, Northwestern University; Evanston, 60208, USA
| | - Ryan McKeown
- Department of Molecular Biosciences, Northwestern University; Evanston, 60208, USA
| | - Sylvia E. J. Fischer
- Division of Infectious Diseases, Department of Pediatrics, Boston Children’s Hospital and Harvard Medical School; Boston, 02115, USA
| | - Erik C. Andersen
- Department of Molecular Biosciences, Northwestern University; Evanston, 60208, USA
| | - Dennis H. Kim
- Division of Infectious Diseases, Department of Pediatrics, Boston Children’s Hospital and Harvard Medical School; Boston, 02115, USA
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19
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Fox BW, Helf MJ, Burkhardt RN, Artyukhin AB, Curtis BJ, Palomino DF, Chaturbedi A, Tauffenberger A, Wrobel CJ, Zhang YK, Lee SS, Schroeder FC. Evolutionarily related host and microbial pathways regulate fat desaturation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.31.555782. [PMID: 37693574 PMCID: PMC10491262 DOI: 10.1101/2023.08.31.555782] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/12/2023]
Abstract
Fatty acid desaturation is central to metazoan lipid metabolism and provides building blocks of membrane lipids and precursors of diverse signaling molecules. Nutritional conditions and associated microbiota regulate desaturase expression1-4, but the underlying mechanisms have remained unclear. Here, we show that endogenous and microbiota-dependent small molecule signals promote lipid desaturation via the nuclear receptor NHR-49/PPARα in C. elegans. Untargeted metabolomics of a β-oxidation mutant, acdh-11, in which expression of the stearoyl-CoA desaturase FAT-7/SCD1 is constitutively increased, revealed accumulation of a β-cyclopropyl fatty acid, becyp#1, that potently activates fat-7 expression via NHR-49. Biosynthesis of becyp#1 is strictly dependent on expression of cyclopropane synthase by associated bacteria, e.g., E. coli. Screening for structurally related endogenous metabolites revealed a β-methyl fatty acid, bemeth#1, whose activity mimics that of microbiota-dependent becyp#1, but is derived from a methyltransferase, fcmt-1, that is conserved across Nematoda and likely originates from bacterial cyclopropane synthase via ancient horizontal gene transfer. Activation of fat-7 expression by these structurally similar metabolites is controlled by distinct mechanisms, as microbiota-dependent becyp#1 is metabolized by a dedicated β-oxidation pathway, while the endogenous bemeth#1 is metabolized via α-oxidation. Collectively, we demonstrate that evolutionarily related biosynthetic pathways in metazoan host and associated microbiota converge on NHR-49/PPARα to regulate fat desaturation.
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Affiliation(s)
- Bennett W. Fox
- Boyce Thompson Institute and Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
| | - Maximilian J. Helf
- Boyce Thompson Institute and Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
| | - Russell N. Burkhardt
- Boyce Thompson Institute and Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
| | - Alexander B. Artyukhin
- Chemistry Department, College of Environmental Science and Forestry, State University of New York, Syracuse, New York 13210, United States
| | - Brian J. Curtis
- Boyce Thompson Institute and Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
| | - Diana Fajardo Palomino
- Boyce Thompson Institute and Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
| | - Amaresh Chaturbedi
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York 14853, United States
| | - Arnaud Tauffenberger
- Boyce Thompson Institute and Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
| | - Chester J.J. Wrobel
- Boyce Thompson Institute and Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
| | - Ying K. Zhang
- Boyce Thompson Institute and Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
| | - Siu Sylvia Lee
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York 14853, United States
| | - Frank C. Schroeder
- Boyce Thompson Institute and Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
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Muthubharathi BC, Ravichandiran V, Balamurugan K. Distinct global metabolomic profiles of the model organism Caenorhabditis elegans during interactions with Staphylococcus aureus and Salmonella enterica Serovar Typhi. Mol Omics 2023; 19:574-584. [PMID: 37272185 DOI: 10.1039/d3mo00040k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The interactive network of hosts with pathogenic microbes is still questionable. It has been hypothesized and reported that the host shows altered regulatory mechanisms for different pathogens. Several studies using transcriptomics and proteomics revealed the altered pathways and sequential regulations displayed by the host during bacterial interactions. Still, there is a gap in understanding the triggering molecule at transcriptomic and proteomic levels due to the lack of the knowledge of the interactive metabolites produced during their interactions. In this study, the global metabolomic approach was performed in the nematode model organism Caenorhabditis elegans upon exposure to a Gram-negative bacteria, Salmonella enterica Serovar Typhi, and a Gram-positive bacteria, Staphylococcus aureus, and the whole metabolome was categorized as endo-metabolome (internally produced) and exo-metabolome (externally releasing). The extracted metabolites were subjected to liquid chromatography mass spectrometry (ESI-LC/qToF-MS/MS). In total 5578, 4554 and 4046 endo-metabolites and 4451, 3625 and 1281 exo-metabolites were identified in C. elegans when exposed to E. coli OP50, S. Typhi and S. aureus, respectively. Both the multivariate and univariate analyses were performed. The variation in endo- and exo-metabolome during candidate bacterial interactions was observed. The results indicated that, during S. aureus interaction, the exclusively enriched metabolites were significantly involved in alpha-linoleic acid metabolism. Similarly, the exclusively enriched metabolites during the interaction of S. Typhi were significantly involved in the phosphatidylinositol signalling system. The whole metabolomic profile presented here will build the scope to understand the role of metabolites and the respective pathways in host response during the early period of bacterial infections.
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21
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Bollen DP, Reddy KC, Kim DH, Colaiácovo MP. Germline mitotic quiescence and programmed cell death are induced in C. elegans by exposure to pathogenic P. aeruginosa. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.08.552522. [PMID: 37609207 PMCID: PMC10441368 DOI: 10.1101/2023.08.08.552522] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/24/2023]
Abstract
The impact of exposure to microbial pathogens on animal reproductive capacity and germline physiology is not well understood. The nematode Caenorhabditis elegans is a bacterivore that encounters pathogenic microbes in its natural environment. How pathogenic bacteria affect host reproductive capacity of C. elegans is not well understood. Here, we show that exposure of C. elegans hermaphrodites to the Gram-negative pathogen Pseudomonas aeruginosa causes a marked reduction in brood size with concomitant reduction in the number of nuclei in the germline and gonad size. We define two processes that are induced that contribute to the decrease in the number of germ cell nuclei. First, we observe that infection with P. aeruginosa leads to the induction of programmed germ cell death. Second, we observe that this exposure induces mitotic quiescence in the proliferative zone of the C. elegans gonad. Importantly, these processes appear to be reversible; when animals are removed from the presence of P. aeruginosa, germ cell death is abated, germ cell nuclei numbers increase, and brood sizes recover. The reversible germline dynamics during exposure to P. aeruginosa may represent an adaptive response to improve survival of progeny and may serve to facilitate resource allocation that promotes survival during pathogen infection.
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Affiliation(s)
- Daniel P. Bollen
- Division of Infectious Diseases and Department of Pediatrics, Boston Children’s Hospital and Harvard Medical School, Boston, MA 02115, USA
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Kirthi C. Reddy
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Dennis H. Kim
- Division of Infectious Diseases and Department of Pediatrics, Boston Children’s Hospital and Harvard Medical School, Boston, MA 02115, USA
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22
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Beydoun S, Kitto ES, Wang E, Huang S, Leiser SF. Methodology to Metabolically Inactivate Bacteria for Caenorhabditis elegans Research. J Vis Exp 2023:10.3791/65775. [PMID: 37578251 PMCID: PMC11064985 DOI: 10.3791/65775] [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] [Indexed: 08/15/2023] Open
Abstract
Caenorhabditis elegans is a common model organism for research in genetics, development, aging, metabolism, and behavior. Because C. elegans consume a diet of live bacteria, the metabolic activity of their food source can confound experiments looking for the direct effects of various interventions on the worm. To avoid the confounding effects of bacterial metabolism, C. elegans researchers have used multiple methods to metabolically inactivate bacteria, including ultraviolet (UV)-irradiation, heat-killing, and antibiotics. UV treatment is relatively low-throughput and cannot be used in liquid culture because each plate must be examined for successful bacterial killing. A second treatment method, heat-killing, negatively affects the texture and nutritional quality of the bacteria, leading to the developmental arrest of C. elegans. Finally, antibiotic treatment can directly alter C. elegans physiology in addition to preventing bacterial growth. This manuscript describes an alternative method to metabolically inactivate bacteria using paraformaldehyde (PFA). PFA treatment cross-links proteins within bacterial cells to prevent metabolic activity while preserving cellular structure and nutritional content. This method is high-throughput and can be used in liquid culture or solid plates, as testing one plate of PFA-treated bacteria for growth validates the whole batch. Metabolic inactivation through PFA treatment can be used to eliminate the confounding effects of bacterial metabolism on studies of drug or metabolite supplementation, stress resistance, metabolomics, and behavior in C. elegans.
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Affiliation(s)
- Safa Beydoun
- Molecular and Integrative Physiology Department, University of Michigan, Ann Arbor
| | - Elizabeth S Kitto
- Molecular and Integrative Physiology Department, University of Michigan, Ann Arbor
| | - Emily Wang
- Molecular and Integrative Physiology Department, University of Michigan, Ann Arbor
| | - Shijiao Huang
- Molecular and Integrative Physiology Department, University of Michigan, Ann Arbor
| | - Scott F Leiser
- Molecular and Integrative Physiology Department, University of Michigan, Ann Arbor; Department of Internal Medicine, University of Michigan, Ann Arbor;
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23
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Maushe D, Ogi V, Divakaran K, Verdecia Mogena AM, Himmighofen PA, Machado RAR, Towbin BD, Ehlers RU, Molina C, Parisod C, Maud Robert CA. Stress tolerance in entomopathogenic nematodes: Engineering superior nematodes for precision agriculture. J Invertebr Pathol 2023:107953. [PMID: 37336478 DOI: 10.1016/j.jip.2023.107953] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Revised: 06/13/2023] [Accepted: 06/16/2023] [Indexed: 06/21/2023]
Abstract
Entomopathogenic nematodes (EPNs) are soil-dwelling parasitic roundworms commonly used as biocontrol agents of insect pests in agriculture. EPN dauer juveniles locate and infect a host in which they will grow and multiply until resource depletion. During their free-living stage, EPNs face a series of internal and environmental stresses. Their ability to overcome these challenges is crucial to determine their infection success and survival. In this review, we provide a comprehensive overview of EPN response to stresses associated with starvation, low/elevated temperatures, desiccation, osmotic stress, hypoxia, and ultra-violet light. We further report EPN defense strategies to cope with biotic stressors such as viruses, bacteria, fungi, and predatory insects. By comparing the genetic and biochemical basis of these strategies to the nematode model Caenorhabditis elegans, we provide new avenues and targets to select and engineer precision nematodes adapted to specific field conditions.
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Affiliation(s)
- Dorothy Maushe
- Institute of Plant Sciences, University of Bern, Altenbergrain 21, CH-3013 Bern, Switzerland
| | - Vera Ogi
- Institute of Plant Sciences, University of Bern, Altenbergrain 21, CH-3013 Bern, Switzerland
| | - Keerthi Divakaran
- Institute of Plant Sciences, University of Bern, Altenbergrain 21, CH-3013 Bern, Switzerland
| | | | - Paul Anton Himmighofen
- Institute of Plant Sciences, University of Bern, Altenbergrain 21, CH-3013 Bern, Switzerland
| | - Ricardo A R Machado
- Institute of Biology, University of Neuchâtel, Rue Emile Argand 11, CH-2000 Neuchâtel, Switzerland
| | - Benjamin Daniel Towbin
- Institute of Cell Biology, University of Bern, Baltzerstrasse 4, CH-3012 Bern, Switzerland
| | - Ralf-Udo Ehlers
- e- nema GmbH, Klausdorfer Str. 28-36, DE-24223 Schwentinental, Germany
| | - Carlos Molina
- e- nema GmbH, Klausdorfer Str. 28-36, DE-24223 Schwentinental, Germany
| | - Christian Parisod
- Department of Biology, University of Fribourg, Chemin du Musée 10, CH-1700 Fribourg, Switzerland
| | - Christelle Aurélie Maud Robert
- Institute of Plant Sciences, University of Bern, Altenbergrain 21, CH-3013 Bern, Switzerland; Oeschger Centre for Climate Change Research, University of Bern, Hochschulstrasse 4, CH-3012 Bern, Switzerland.
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Tang M, Ding G, Li L, Xiao G, Wang D. Exposure to polystyrene nanoparticles at predicted environmental concentrations enhances toxic effects of Acinetobacter johnsonii AC15 infection on Caenorhabditis elegans. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2023; 262:115131. [PMID: 37315368 DOI: 10.1016/j.ecoenv.2023.115131] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Revised: 06/07/2023] [Accepted: 06/10/2023] [Indexed: 06/16/2023]
Abstract
Nanoplastics and microbial pathogens are both widely distributed in the environment; however, their combined toxicity remains largely unclear. Using Caenorhabditis elegans as an animal model, we examined the possible effect of exposure to polystyrene nanoparticle (PS-NP) in Acinetobacter johnsonii AC15 (a bacterial pathogen) infected animals. Exposure to PS-NP at the concentrations of 0.1-10 μg/L significantly enhanced the toxicity of Acinetobacter johnsonii AC15 infection on lifespan and locomotion behaviors. In addition, after exposure to 0.1-10 μg/L PS-NP, the accumulation of Acinetobacter johnsonii AC15 in body of nematodes was also increased. Meanwhile, the innate immune response indicated by the increase of antimicrobial gene expressions in Acinetobacter johnsonii AC15 infected nematodes was suppressed by exposure to 0.1-10 μg/L PS-NP. Moreover, expressions of egl-1, dbl-1, bar-1, daf-16, pmk-1, and elt-2 governing the bacterial infection and immunity in Acinetobacter johnsonii AC15 infected nematodes were further inhibited by exposure to 0.1-10 μg/L PS-NP. Therefore, our data suggested the possible exposure risk of nanoplastic at predicted environmental concentrations in enhancing the toxic effects of bacterial pathogens on environmental organisms.
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Affiliation(s)
- Mingfeng Tang
- College of Biology and Food Engineering, Chongqing Three Gorges University, Wanzhou, China
| | - Guoying Ding
- College of Biology and Food Engineering, Chongqing Three Gorges University, Wanzhou, China
| | - Liane Li
- College of Biology and Food Engineering, Chongqing Three Gorges University, Wanzhou, China
| | - Guosheng Xiao
- College of Biology and Food Engineering, Chongqing Three Gorges University, Wanzhou, China.
| | - Dayong Wang
- College of Biology and Food Engineering, Chongqing Three Gorges University, Wanzhou, China; Medical School, Southeast University, Nanjing, China.
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25
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Rua R, Pujol N. Pathogen metabolite checkpoint: NHR on guard. Immunity 2023; 56:744-746. [PMID: 37044064 DOI: 10.1016/j.immuni.2023.03.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/14/2023]
Abstract
How can beneficial microorganisms be distinguished from pathogenic ones? In this issue of Immunity, Peterson et al. discovered that a specific phenazine, which is part of a family of toxic metabolites expressed by pathogenic bacteria, is detected by Caenorhabditis elegans by directly binding to a nuclear hormone receptor, promoting the expression of detoxifying enzymes and immunity-related genes, thus protecting the worm.
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Affiliation(s)
- Rejane Rua
- Aix-Marseille University, CNRS, INSERM, Centre d'Immunologie de Marseille-Luminy (CIML), Turing Centre for Living Systems, Marseille, France.
| | - Nathalie Pujol
- Aix-Marseille University, CNRS, INSERM, Centre d'Immunologie de Marseille-Luminy (CIML), Turing Centre for Living Systems, Marseille, France.
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26
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Hao X, Chen J, Li Y, Liu X, Li Y, Wang B, Cao J, Gu Y, Ma W, Ma L. Molecular Defense Response of Bursaphelenchus xylophilus to the Nematophagous Fungus Arthrobotrys robusta. Cells 2023; 12:cells12040543. [PMID: 36831210 PMCID: PMC9953903 DOI: 10.3390/cells12040543] [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: 11/23/2022] [Revised: 01/14/2023] [Accepted: 02/06/2023] [Indexed: 02/10/2023] Open
Abstract
Bursaphelenchus xylophilus causes pine wilt disease, which poses a serious threat to forestry ecology around the world. Microorganisms are environmentally friendly alternatives to the use of chemical nematicides to control B. xylophilus in a sustainable way. In this study, we isolated a nematophagous fungus-Arthrobotrys robusta-from the xylem of diseased Pinus massoniana. The nematophagous activity of A. robusta against the PWNs was observed after just 6 h. We found that B. xylophilus entered the trap of A. robusta at 24 h, and the nervous system and immunological response of B. xylophilus were stimulated by metabolites that A. robusta produced. At 30 h of exposure to A. robusta, B. xylophilus exhibited significant constriction, and we were able to identify xenobiotics. Bursaphelenchus xylophilus activated xenobiotic metabolism, which expelled the xenobiotics from their bodies, by providing energy through lipid metabolism. When PWNs were exposed to A. robusta for 36 h, lysosomal and autophagy-related genes were activated, and the bodies of the nematodes underwent disintegration. Moreover, a gene co-expression pattern network was constructed by WGCNA and Cytoscape. The gene co-expression pattern network suggested that metabolic processes, developmental processes, detoxification, biological regulation, and signaling were influential when the B. xylophilus specimens were exposed to A. robusta. Additionally, bZIP transcription factors, ankyrin, ATPases, innexin, major facilitator, and cytochrome P450 played critical roles in the network. This study proposes a model in which mobility improved whenever B. xylophilus entered the traps of A. robusta. The model will provide a solid foundation with which to understand the molecular and evolutionary mechanisms underlying interactions between nematodes and nematophagous fungi. Taken together, these findings contribute in several ways to our understanding of B. xylophilus exposed to microorganisms and provide a basis for establishing an environmentally friendly prevention and control strategy.
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Affiliation(s)
- Xin Hao
- School of Forestry, Northeast Forestry University, Harbin 150040, China
| | - Jie Chen
- School of Forestry, Northeast Forestry University, Harbin 150040, China
| | - Yongxia Li
- Key Laboratory of Forest Protection, National Forestry and Grassland Administration, Ecology and Nature Conservation Institute, Chinese Academy of Forestry, Beijing 100091, China
| | - Xuefeng Liu
- School of Forestry, Northeast Forestry University, Harbin 150040, China
| | - Yang Li
- School of Forestry, Northeast Forestry University, Harbin 150040, China
- China Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China
| | - Bowen Wang
- School of Art and Archaeology, Zhejiang University, Hangzhou 310028, China
| | - Jingxin Cao
- School of Forestry, Northeast Forestry University, Harbin 150040, China
| | - Yaru Gu
- School of Forestry, Northeast Forestry University, Harbin 150040, China
| | - Wei Ma
- College of Pharmaceutical Sciences, Heilongjiang University of Chinese Medicine, Harbin 150040, China
| | - Ling Ma
- School of Forestry, Northeast Forestry University, Harbin 150040, China
- Correspondence:
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27
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Wu T, Ge M, Wu M, Duan F, Liang J, Chen M, Gracida X, Liu H, Yang W, Dar AR, Li C, Butcher RA, Saltzman AL, Zhang Y. Pathogenic bacteria modulate pheromone response to promote mating. Nature 2023; 613:324-331. [PMID: 36599989 PMCID: PMC10732163 DOI: 10.1038/s41586-022-05561-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2021] [Accepted: 11/11/2022] [Indexed: 01/05/2023]
Abstract
Pathogens generate ubiquitous selective pressures and host-pathogen interactions alter social behaviours in many animals1-4. However, very little is known about the neuronal mechanisms underlying pathogen-induced changes in social behaviour. Here we show that in adult Caenorhabditis elegans hermaphrodites, exposure to a bacterial pathogen (Pseudomonas aeruginosa) modulates sensory responses to pheromones by inducing the expression of the chemoreceptor STR-44 to promote mating. Under standard conditions, C. elegans hermaphrodites avoid a mixture of ascaroside pheromones to facilitate dispersal5-13. We find that exposure to the pathogenic Pseudomonas bacteria enables pheromone responses in AWA sensory neurons, which mediate attractive chemotaxis, to suppress the avoidance. Pathogen exposure induces str-44 expression in AWA neurons, a process regulated by a transcription factor zip-5 that also displays a pathogen-induced increase in expression in AWA. STR-44 acts as a pheromone receptor and its function in AWA neurons is required for pathogen-induced AWA pheromone response and suppression of pheromone avoidance. Furthermore, we show that C. elegans hermaphrodites, which reproduce mainly through self-fertilization, increase the rate of mating with males after pathogen exposure and that this increase requires str-44 in AWA neurons. Thus, our results uncover a causal mechanism for pathogen-induced social behaviour plasticity, which can promote genetic diversity and facilitate adaptation of the host animals.
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Affiliation(s)
- Taihong Wu
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, USA
- Center for Brain Science, Harvard University, Cambridge, MA, USA
| | - Minghai Ge
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, USA
- Center for Brain Science, Harvard University, Cambridge, MA, USA
| | - Min Wu
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, USA
- Center for Brain Science, Harvard University, Cambridge, MA, USA
| | - Fengyun Duan
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, USA
- Center for Brain Science, Harvard University, Cambridge, MA, USA
| | - Jingting Liang
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, USA
- Center for Brain Science, Harvard University, Cambridge, MA, USA
| | - Maoting Chen
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, USA
- Center for Brain Science, Harvard University, Cambridge, MA, USA
| | - Xicotencatl Gracida
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, USA
- Center for Brain Science, Harvard University, Cambridge, MA, USA
| | - He Liu
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, USA
- Center for Brain Science, Harvard University, Cambridge, MA, USA
| | - Wenxing Yang
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, USA
- Center for Brain Science, Harvard University, Cambridge, MA, USA
| | - Abdul Rouf Dar
- Department of Chemistry, University of Florida, Gainesville, FL, USA
| | - Chengyin Li
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario, Canada
| | - Rebecca A Butcher
- Department of Chemistry, University of Florida, Gainesville, FL, USA
| | - Arneet L Saltzman
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario, Canada
| | - Yun Zhang
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, USA.
- Center for Brain Science, Harvard University, Cambridge, MA, USA.
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28
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McLachlan IG, Kramer TS, Dua M, DiLoreto EM, Gomes MA, Dag U, Srinivasan J, Flavell SW. Diverse states and stimuli tune olfactory receptor expression levels to modulate food-seeking behavior. eLife 2022; 11:e79557. [PMID: 36044259 PMCID: PMC9433090 DOI: 10.7554/elife.79557] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2022] [Accepted: 08/19/2022] [Indexed: 12/24/2022] Open
Abstract
Animals must weigh competing needs and states to generate adaptive behavioral responses to the environment. Sensorimotor circuits are thus tasked with integrating diverse external and internal cues relevant to these needs to generate context-appropriate behaviors. However, the mechanisms that underlie this integration are largely unknown. Here, we show that a wide range of states and stimuli converge upon a single Caenorhabditis elegans olfactory neuron to modulate food-seeking behavior. Using an unbiased ribotagging approach, we find that the expression of olfactory receptor genes in the AWA olfactory neuron is influenced by a wide array of states and stimuli, including feeding state, physiological stress, and recent sensory cues. We identify odorants that activate these state-dependent olfactory receptors and show that altered expression of these receptors influences food-seeking and foraging. Further, we dissect the molecular and neural circuit pathways through which external sensory information and internal nutritional state are integrated by AWA. This reveals a modular organization in which sensory and state-related signals arising from different cell types in the body converge on AWA and independently control chemoreceptor expression. The synthesis of these signals by AWA allows animals to generate sensorimotor responses that reflect the animal's overall state. Our findings suggest a general model in which sensory- and state-dependent transcriptional changes at the sensory periphery modulate animals' sensorimotor responses to meet their ongoing needs and states.
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Affiliation(s)
- Ian G McLachlan
- Picower Institute for Learning and Memory, Department of Brain and Cognitive Sciences, Massachusetts Institute of TechnologyCambridgeUnited States
| | - Talya S Kramer
- Picower Institute for Learning and Memory, Department of Brain and Cognitive Sciences, Massachusetts Institute of TechnologyCambridgeUnited States
- MIT Biology Graduate Program, Massachusetts Institute of TechnologyCambridgeUnited States
| | - Malvika Dua
- Picower Institute for Learning and Memory, Department of Brain and Cognitive Sciences, Massachusetts Institute of TechnologyCambridgeUnited States
| | - Elizabeth M DiLoreto
- Department of Biology and Biotechnology, Worcester Polytechnic InstituteWorcesterUnited States
| | - Matthew A Gomes
- Picower Institute for Learning and Memory, Department of Brain and Cognitive Sciences, Massachusetts Institute of TechnologyCambridgeUnited States
| | - Ugur Dag
- Picower Institute for Learning and Memory, Department of Brain and Cognitive Sciences, Massachusetts Institute of TechnologyCambridgeUnited States
| | - Jagan Srinivasan
- Department of Biology and Biotechnology, Worcester Polytechnic InstituteWorcesterUnited States
| | - Steven W Flavell
- Picower Institute for Learning and Memory, Department of Brain and Cognitive Sciences, Massachusetts Institute of TechnologyCambridgeUnited States
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29
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Basic M, Dardevet D, Abuja PM, Bolsega S, Bornes S, Caesar R, Calabrese FM, Collino M, De Angelis M, Gérard P, Gueimonde M, Leulier F, Untersmayr E, Van Rymenant E, De Vos P, Savary-Auzeloux I. Approaches to discern if microbiome associations reflect causation in metabolic and immune disorders. Gut Microbes 2022; 14:2107386. [PMID: 35939623 PMCID: PMC9361767 DOI: 10.1080/19490976.2022.2107386] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Our understanding of microorganisms residing within our gut and their roles in the host metabolism and immunity advanced greatly over the past 20 years. Currently, microbiome studies are shifting from association and correlation studies to studies demonstrating causality of identified microbiome signatures and identification of molecular mechanisms underlying these interactions. This transformation is crucial for the efficient translation into clinical application and development of targeted strategies to beneficially modulate the intestinal microbiota. As mechanistic studies are still quite challenging to perform in humans, the causal role of microbiota is frequently evaluated in animal models that need to be appropriately selected. Here, we provide a comprehensive overview on approaches that can be applied in addressing causality of host-microbe interactions in five major animal model organisms (Caenorhabditis elegans, Drosophila melanogaster, zebrafish, rodents, and pigs). We particularly focused on discussing methods available for studying the causality ranging from the usage of gut microbiota transfer, diverse models of metabolic and immune perturbations involving nutritional and chemical factors, gene modifications and surgically induced models, metabolite profiling up to culture-based approached. Furthermore, we addressed the impact of the gut morphology, physiology as well as diet on the microbiota composition in various models and resulting species specificities. Finally, we conclude this review with the discussion on models that can be applied to study the causal role of the gut microbiota in the context of metabolic syndrome and host immunity. We hope this review will facilitate important considerations for appropriate animal model selection.
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Affiliation(s)
- Marijana Basic
- Institute for Laboratory Animal Science, Hannover Medical School, Hannover, Germany
| | - Dominique Dardevet
- Human Nutrition Unit, UMR1019, University Clermont Auvergne, INRAE, Clermont-Ferrand, France
| | - Peter Michael Abuja
- Diagnostic & Research Centre of Molecular Biomedicine, Institute of Pathology, Medical University of Graz, Graz, Austria
| | - Silvia Bolsega
- Institute for Laboratory Animal Science, Hannover Medical School, Hannover, Germany
| | - Stéphanie Bornes
- University Clermont Auvergne, Inrae, VetAgro Sup, Umrf, Aurillac, France
| | - Robert Caesar
- The Wallenberg Laboratory, Department of Molecular and Clinical Medicine, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | | | - Massimo Collino
- Rita Levi-Montalcini Department of Neuroscience, University of Turin, Turin, Italy
| | - Maria De Angelis
- Department of Soil, Plant and Science, “Aldo Moro” University Bari, Bari, Italy
| | - Philippe Gérard
- INRAE, AgroParisTech, Micalis Institute, Université Paris-Saclay, France
| | - Miguel Gueimonde
- Department of Microbiology and Biochemistry of Dairy Products, IPLA-CSIC;Villaviciosa, Spain
| | - François Leulier
- Institut de Génomique Fonctionnelle de Lyon, Ecole Normale Supérieure de Lyon, UMR5242 CNRS, Université Claude Bernard-Lyon1, Lyon, France
| | - Eva Untersmayr
- Institute of Pathophysiology and Allergy Research, Center of Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Austria
| | - Evelien Van Rymenant
- Flanders Research Institute for Agriculture, Fisheries and Food (Ilvo), Merelbeke, Belgium
| | - Paul De Vos
- Immunoendocrinology, Division of Medical Biology, Department of Pathology and Medical Biology, University Medical Center Groningen; Groningen, Netherlands
| | - Isabelle Savary-Auzeloux
- Human Nutrition Unit, UMR1019, University Clermont Auvergne, INRAE, Clermont-Ferrand, France,CONTACT Isabelle Savary-Auzeloux Human Nutrition Unit, UMR1019, University Clermont Auvergne, INRAE, Clermont-Ferrand, France
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30
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Pérez-Carrascal OM, Choi R, Massot M, Pees B, Narayan V, Shapira M. Host Preference of Beneficial Commensals in a Microbially-Diverse Environment. Front Cell Infect Microbiol 2022; 12:795343. [PMID: 35782135 PMCID: PMC9240469 DOI: 10.3389/fcimb.2022.795343] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Accepted: 05/24/2022] [Indexed: 11/13/2022] Open
Abstract
Gut bacteria are often described by the neutral term commensals. However, the more we learn about their interactions with hosts, the more apparent it becomes that gut commensals often contribute positively to host physiology and fitness. Whether hosts can prefer beneficial bacteria, and how they do so, is not clear. This is of particular interest in the case of the bacterivore C. elegans, which depends on bacteria as food source, but also as gut colonizers that contribute to its physiology, from development to immunity. It is further unclear to what extent worms living in their microbially-diverse habitats can sense and distinguish between beneficial bacteria, food, and pathogens. Focusing on Enterobacteriaceae and members of closely related families, we isolated gut bacteria from worms raised in compost microcosms, as well as bacteria from the respective environments and evaluated their contributions to host development. Most isolates, from worms or from the surrounding environment, promoted faster development compared to the non-colonizing E. coli food strain. Pantoea strains further showed differential contributions of gut isolates versus an environmental isolate. Characterizing bacterial ability to hinder pathogenic colonization with Pseudomonas aeruginosa, supported the trend of Pantoea gut commensals being beneficial, in contrast to the environmental strain. Interestingly, worms were attracted to the beneficial Pantoea strains, preferring them over non-beneficial bacteria, including the environmental Pantoea strain. While our understanding of the mechanisms underlying these host-microbe interactions are still rudimentary, the results suggest that hosts can sense and prefer beneficial commensals.
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Alterations in Bacterial Metabolism Contribute to the Lifespan Extension Exerted by Guarana in Caenorhabditis elegans. Nutrients 2022; 14:nu14091986. [PMID: 35565952 PMCID: PMC9105138 DOI: 10.3390/nu14091986] [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: 03/31/2022] [Revised: 05/03/2022] [Accepted: 05/05/2022] [Indexed: 02/06/2023] Open
Abstract
Guarana (Paullinia cupana) is a widely consumed nutraceutical with various health benefits supported by scientific evidence. However, its indirect health impacts through the gut microbiota have not been studied. Caenorhabditis elegans is a useful model to study both the direct and indirect effects of nutraceuticals, as the intimate association of the worm with the metabolites produced by Escherichia coli is a prototypic simplified model of our gut microbiota. We prepared an ethanoic extract of guarana seeds and assessed its antioxidant capacity in vitro, with a 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay, and in vivo, utilizing C. elegans. Additionally, we studied the impact of this extract on C. elegans lifespan, utilizing both viable and non-viable E. coli, and assessed the impact of guarana on E. coli folate production. The extract showed high antioxidant capacity, and it extended worm lifespan. However, the antioxidant and life-extending effects did not correlate in terms of the extract concentration. The extract-induced life extension was also less significant when utilizing dead E. coli, which may indicate that the effects of guarana on the worms work partly through modifications on E. coli metabolism. Following this observation, guarana was found to decrease E. coli folate production, revealing one possible route for its beneficial effects.
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32
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Flavell SW, Gordus A. Dynamic functional connectivity in the static connectome of Caenorhabditis elegans. Curr Opin Neurobiol 2022; 73:102515. [PMID: 35183877 PMCID: PMC9621599 DOI: 10.1016/j.conb.2021.12.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Revised: 12/16/2021] [Accepted: 12/22/2021] [Indexed: 01/01/2023]
Abstract
A hallmark of adaptive behavior is the ability to flexibly respond to sensory cues. To understand how neural circuits implement this flexibility, it is critical to resolve how a static anatomical connectome can be modulated such that functional connectivity in the network can be dynamically regulated. Here, we review recent work in the roundworm Caenorhabditis elegans on this topic. EM studies have mapped anatomical connectomes of many C. elegans animals, highlighting the level of stereotypy in the anatomical network. Brain-wide calcium imaging and studies of specified neural circuits have uncovered striking flexibility in the functional coupling of neurons. The coupling between neurons is controlled by neuromodulators that act over long timescales. This gives rise to persistent behavioral states that animals switch between, allowing them to generate adaptive behavioral responses across environmental conditions. Thus, the dynamic coupling of neurons enables multiple behavioral states to be encoded in a physically stereotyped connectome.
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Affiliation(s)
- Steven W Flavell
- Picower Institute for Learning and Memory, Department of Brain & Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA.
| | - Andrew Gordus
- Department of Biology, Solomon H. Snyder Department of Neuroscience, Johns Hopkins University, Baltimore, MD, USA.
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33
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Wibisono P, Wibisono S, Watteyne J, Chen CH, Sellegounder D, Beets I, Liu Y, Sun J. Neuronal GPCR NMUR-1 regulates distinct immune responses to different pathogens. Cell Rep 2022; 38:110321. [PMID: 35139379 PMCID: PMC8869846 DOI: 10.1016/j.celrep.2022.110321] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Revised: 11/21/2021] [Accepted: 01/10/2022] [Indexed: 12/29/2022] Open
Abstract
A key question in current immunology is how the innate immune system generates high levels of specificity. Using the Caenorhabditis elegans model system, we demonstrate that functional loss of NMUR-1, a neuronal G-protein-coupled receptor homologous to mammalian receptors for the neuropeptide neuromedin U, has diverse effects on C. elegans innate immunity against various bacterial pathogens. Transcriptomic analyses and functional assays reveal that NMUR-1 modulates C. elegans transcription activity by regulating the expression of transcription factors involved in binding to RNA polymerase II regulatory regions, which, in turn, controls the expression of distinct immune genes in response to different pathogens. These results uncover a molecular basis for the specificity of C. elegans innate immunity. Given the evolutionary conservation of NMUR-1 signaling in immune regulation across multicellular organisms, our study could provide mechanistic insights into understanding the specificity of innate immunity in other animals, including mammals.
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Affiliation(s)
- Phillip Wibisono
- Department of Translational Medicine and Physiology, Elson S. Floyd College of Medicine, Washington State University, Spokane, WA, USA
| | - Shawndra Wibisono
- Department of Translational Medicine and Physiology, Elson S. Floyd College of Medicine, Washington State University, Spokane, WA, USA
| | - Jan Watteyne
- Department of Biology, KU Leuven, Leuven, Belgium
| | - Chia-Hui Chen
- Department of Translational Medicine and Physiology, Elson S. Floyd College of Medicine, Washington State University, Spokane, WA, USA
| | - Durai Sellegounder
- Department of Translational Medicine and Physiology, Elson S. Floyd College of Medicine, Washington State University, Spokane, WA, USA
| | - Isabel Beets
- Department of Biology, KU Leuven, Leuven, Belgium
| | - Yiyong Liu
- Department of Translational Medicine and Physiology, Elson S. Floyd College of Medicine, Washington State University, Spokane, WA, USA; Genomics Core, Washington State University, Spokane, WA, USA.
| | - Jingru Sun
- Department of Translational Medicine and Physiology, Elson S. Floyd College of Medicine, Washington State University, Spokane, WA, USA.
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Chou SH, Chen YJ, Liao CP, Pan CL. A role for dopamine in C. elegans avoidance behavior induced by mitochondrial stress. Neurosci Res 2022; 178:87-92. [PMID: 35074444 DOI: 10.1016/j.neures.2022.01.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Revised: 12/21/2021] [Accepted: 01/17/2022] [Indexed: 01/11/2023]
Abstract
Physiological stress triggers aversive learning that profoundly alters animal behavior. Systemic mitochondrial disruption induces avoidance of C. elegans to non-pathogenic food bacteria. Mutations in cat-2 and dat-1, which control dopamine synthesis and reuptake, respectively, impair this learned bacterial avoidance, suggesting that dopaminergic modulation is essential. Cell-specific rescue experiments indicate that dopamine likely acts from the CEP and ADE neurons to regulate learned bacterial avoidance. We find that mutations in multiple dopamine receptor genes, including dop-1, dop-2 and dop-3, reduced learned bacterial avoidance. Our work reveals a role for dopamine signaling in C. elegans learned avoidance behavior induced by mitochondrial stress.
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Affiliation(s)
- Shih-Hua Chou
- Institute of Molecular Medicine, College of Medicine, National Taiwan University, Taipei 10002, Taiwan; Center of Precision Medicine, College of Medicine, National Taiwan University, Taipei 10002, Taiwan
| | - Yen-Ju Chen
- Institute of Molecular Medicine, College of Medicine, National Taiwan University, Taipei 10002, Taiwan; Center of Precision Medicine, College of Medicine, National Taiwan University, Taipei 10002, Taiwan
| | - Chien-Po Liao
- Institute of Molecular Medicine, College of Medicine, National Taiwan University, Taipei 10002, Taiwan
| | - Chun-Liang Pan
- Institute of Molecular Medicine, College of Medicine, National Taiwan University, Taipei 10002, Taiwan; Center of Precision Medicine, College of Medicine, National Taiwan University, Taipei 10002, Taiwan.
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Cao M, Schwartz HT, Tan CH, Sternberg PW. The entomopathogenic nematode Steinernema hermaphroditum is a self-fertilizing hermaphrodite and a genetically tractable system for the study of parasitic and mutualistic symbiosis. Genetics 2022; 220:iyab170. [PMID: 34791196 PMCID: PMC8733455 DOI: 10.1093/genetics/iyab170] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Accepted: 09/29/2021] [Indexed: 11/12/2022] Open
Abstract
Entomopathogenic nematodes (EPNs), including Heterorhabditis and Steinernema, are parasitic to insects and contain mutualistically symbiotic bacteria in their intestines (Photorhabdus and Xenorhabdus, respectively) and therefore offer opportunities to study both mutualistic and parasitic symbiosis. The establishment of genetic tools in EPNs has been impeded by limited genetic tractability, inconsistent growth in vitro, variable cryopreservation, and low mating efficiency. We obtained the recently described Steinernema hermaphroditum strain CS34 and optimized its in vitro growth, with a rapid generation time on a lawn of its native symbiotic bacteria Xenorhabdus griffiniae. We developed a simple and efficient cryopreservation method. Previously, S. hermaphroditum isolated from insect hosts was described as producing hermaphrodites in the first generation. We discovered that CS34, when grown in vitro, produced consecutive generations of autonomously reproducing hermaphrodites accompanied by rare males. We performed mutagenesis screens in S. hermaphroditum that produced mutant lines with visible and heritable phenotypes. Genetic analysis of the mutants demonstrated that this species reproduces by self-fertilization rather than parthenogenesis and that its sex is determined chromosomally. Genetic mapping has thus far identified markers on the X chromosome and three of four autosomes. We report that S. hermaphroditum CS34 is the first consistently hermaphroditic EPN and is suitable for genetic model development to study naturally occurring mutualistic symbiosis and insect parasitism.
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Affiliation(s)
- Mengyi Cao
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Hillel T Schwartz
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Chieh-Hsiang Tan
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Paul W Sternberg
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
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Abstract
Studies of C. elegans behavior have been crucial in identifying genetic pathways that control nervous system development and function, as well as basic principles of neural circuit function. Modern analysis of C. elegans behavior commonly relies on video recordings of animals, followed by automated image analysis and behavior quantification. Here, we describe two methods for recording and quantifying C. elegans behavior: a single-worm tracking approach that provides high-resolution behavioral data for individual animals and a multi-worm tracking approach that allows for quantification of the behavior of many animals in parallel. These approaches should be useful to a wide range of researchers studying the nervous system and behavior of C. elegans.
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Affiliation(s)
- Navin Pokala
- Department of Biological and Chemical Sciences, Theobald Science Center, New York Institute of Technology, Old Westbury, NY, USA.
| | - Steven W Flavell
- Department of Brain & Cognitive Sciences, Picower Institute for Learning & Memory, Massachusetts Institute of Technology, Cambridge, MA, USA.
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Wallace SW, Lizzappi MC, Magemizoğlu E, Hur H, Liang Y, Shaham S. Nuclear hormone receptors promote gut and glia detoxifying enzyme induction and protect C. elegans from the mold P. brevicompactum. Cell Rep 2021; 37:110166. [PMID: 34965433 PMCID: PMC8733895 DOI: 10.1016/j.celrep.2021.110166] [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: 07/15/2021] [Revised: 10/19/2021] [Accepted: 12/02/2021] [Indexed: 11/03/2022] Open
Abstract
Animals encounter microorganisms in their habitats, adapting physiology and behavior accordingly. The nematode Caenorhabditis elegans is found in microbe-rich environments; however, its responses to fungi are not extensively studied. Here, we describe interactions of C. elegans and Penicillium brevicompactum, an ecologically relevant mold. Transcriptome studies reveal that co-culture upregulates stress response genes, including xenobiotic-metabolizing enzymes (XMEs), in C. elegans intestine and AMsh glial cells. The nuclear hormone receptors (NHRs) NHR-45 and NHR-156 are induction regulators, and mutants that cannot induce XMEs in the intestine when exposed to P. brevicompactum experience mitochondrial stress and exhibit developmental defects. Different C. elegans wild isolates harbor sequence polymorphisms in nhr-156, resulting in phenotypic diversity in AMsh glia responses to microbe exposure. We propose that P. brevicompactum mitochondria-targeting mycotoxins are deactivated by intestinal detoxification, allowing tolerance to moldy environments. Our studies support the idea that C. elegans NHRs may be regulated by environmental cues.
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Affiliation(s)
- Sean W Wallace
- Laboratory of Developmental Genetics, The Rockefeller University, 1230 York Avenue, New York, NY 10065, USA
| | - Malcolm C Lizzappi
- Laboratory of Developmental Genetics, The Rockefeller University, 1230 York Avenue, New York, NY 10065, USA
| | - Elif Magemizoğlu
- Laboratory of Developmental Genetics, The Rockefeller University, 1230 York Avenue, New York, NY 10065, USA
| | - Hong Hur
- CCTS Research Bioinformatics, The Rockefeller University, 1230 York Avenue, New York, NY 10065, USA
| | - Yupu Liang
- CCTS Research Bioinformatics, The Rockefeller University, 1230 York Avenue, New York, NY 10065, USA
| | - Shai Shaham
- Laboratory of Developmental Genetics, The Rockefeller University, 1230 York Avenue, New York, NY 10065, USA.
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Ji N, Madan GK, Fabre GI, Dayan A, Baker CM, Kramer TS, Nwabudike I, Flavell SW. A neural circuit for flexible control of persistent behavioral states. eLife 2021; 10:e62889. [PMID: 34792019 PMCID: PMC8660023 DOI: 10.7554/elife.62889] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2020] [Accepted: 11/17/2021] [Indexed: 11/29/2022] Open
Abstract
To adapt to their environments, animals must generate behaviors that are closely aligned to a rapidly changing sensory world. However, behavioral states such as foraging or courtship typically persist over long time scales to ensure proper execution. It remains unclear how neural circuits generate persistent behavioral states while maintaining the flexibility to select among alternative states when the sensory context changes. Here, we elucidate the functional architecture of a neural circuit controlling the choice between roaming and dwelling states, which underlie exploration and exploitation during foraging in C. elegans. By imaging ensemble-level neural activity in freely moving animals, we identify stereotyped changes in circuit activity corresponding to each behavioral state. Combining circuit-wide imaging with genetic analysis, we find that mutual inhibition between two antagonistic neuromodulatory systems underlies the persistence and mutual exclusivity of the neural activity patterns observed in each state. Through machine learning analysis and circuit perturbations, we identify a sensory processing neuron that can transmit information about food odors to both the roaming and dwelling circuits and bias the animal towards different states in different sensory contexts, giving rise to context-appropriate state transitions. Our findings reveal a potentially general circuit architecture that enables flexible, sensory-driven control of persistent behavioral states.
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Affiliation(s)
- Ni Ji
- Picower Institute for Learning & Memory, Department of Brain & Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, United States
| | - Gurrein K Madan
- Picower Institute for Learning & Memory, Department of Brain & Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, United States
| | - Guadalupe I Fabre
- Picower Institute for Learning & Memory, Department of Brain & Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, United States
| | - Alyssa Dayan
- Picower Institute for Learning & Memory, Department of Brain & Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, United States
| | - Casey M Baker
- Picower Institute for Learning & Memory, Department of Brain & Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, United States
| | - Talya S Kramer
- Picower Institute for Learning & Memory, Department of Brain & Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, United States
- MIT Biology Graduate Program, Massachusetts Institute of Technology, Cambridge, United States
| | - Ijeoma Nwabudike
- Picower Institute for Learning & Memory, Department of Brain & Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, United States
| | - Steven W Flavell
- Picower Institute for Learning & Memory, Department of Brain & Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, United States
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Pujol N, Ewbank JJ. C. elegans: out on an evolutionary limb. Immunogenetics 2021; 74:63-73. [PMID: 34761293 DOI: 10.1007/s00251-021-01231-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Accepted: 10/22/2021] [Indexed: 12/18/2022]
Abstract
The natural environment of the free-living nematode Caenorhabditis elegans is rich in pathogenic microbes. There is now ample evidence to indicate that these pathogens exert a strong selection pressure on C. elegans, and have shaped its genome, physiology, and behaviour. In this short review, we concentrate on how C. elegans stands out from other animals in terms of its immune repertoire and innate immune signalling pathways. We discuss how C. elegans often detects pathogens because of their effects on essential cellular processes, or organelle integrity, in addition to direct microbial recognition. We illustrate the extensive molecular plasticity that is characteristic of immune defences in C. elegans and highlight some remarkable instances of lineage-specific innovation in innate immune mechanisms.
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Affiliation(s)
- Nathalie Pujol
- Aix Marseille Univ, CNRS, INSERM, CIML, Turing Centre for Living Systems, Marseille, France.
| | - Jonathan J Ewbank
- Aix Marseille Univ, CNRS, INSERM, CIML, Turing Centre for Living Systems, Marseille, France
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40
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An integrated view of innate immune mechanisms in C. elegans. Biochem Soc Trans 2021; 49:2307-2317. [PMID: 34623403 DOI: 10.1042/bst20210399] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Revised: 09/16/2021] [Accepted: 09/20/2021] [Indexed: 12/13/2022]
Abstract
The simple notion 'infection causes an immune response' is being progressively refined as it becomes clear that immune mechanisms cannot be understood in isolation, but need to be considered in a more global context with other cellular and physiological processes. In part, this reflects the deployment by pathogens of virulence factors that target diverse cellular processes, such as translation or mitochondrial respiration, often with great molecular specificity. It also reflects molecular cross-talk between a broad range of host signalling pathways. Studies with the model animal C. elegans have uncovered a range of examples wherein innate immune responses are intimately connected with different homeostatic mechanisms, and can influence reproduction, ageing and neurodegeneration, as well as various other aspects of its biology. Here we provide a short overview of a number of such connections, highlighting recent discoveries that further the construction of a fully integrated view of innate immunity.
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Grover M, Fasseas MK, Essmann C, Liu K, Braendle C, Félix MA, Glockling SL, Barkoulas M. Infection of C. elegans by Haptoglossa Species Reveals Shared Features in the Host Response to Oomycete Detection. Front Cell Infect Microbiol 2021; 11:733094. [PMID: 34722333 PMCID: PMC8552708 DOI: 10.3389/fcimb.2021.733094] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Accepted: 09/22/2021] [Indexed: 11/13/2022] Open
Abstract
Oomycetes are a group of eukaryotic organisms that includes many important pathogens of animals and plants. Within this group, the Haptoglossa genus is characterised by the presence of specialised gun cells carrying a harpoon-like infection apparatus. While several Haptoglossa pathogens have been morphologically described, there are currently no host systems developed to study the infection process or host responses in the lab. In this study, we report that Haptoglossa species are potent natural pathogens of Caenorhabditis nematodes. Using electron microscopy, we characterise the infection process in C. elegans and demonstrate that the oomycete causes excessive tissue degradation upon entry in the body cavity, whilst leaving the host cuticle intact. We also report that the host transcriptional response to Haptoglossa infection shares similarities with the response against the oomycete Myzocytiopsis humicola, a key example of which is the induction of chitinase-like (chil) genes in the hypodermis. We demonstrate that this shared feature of the host response can be mounted by pathogen detection without any infection, as previously shown for M. humicola. These results highlight similarities in the nematode immune response to natural infection by phylogenetically distinct oomycetes.
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Affiliation(s)
- Manish Grover
- Department of Life Sciences, Imperial College, London, United Kingdom
| | - Michael K Fasseas
- Department of Life Sciences, Imperial College, London, United Kingdom
| | - Clara Essmann
- Department of Life Sciences, Imperial College, London, United Kingdom
| | - Kenneth Liu
- Department of Life Sciences, Imperial College, London, United Kingdom
| | | | - Marie-Anne Félix
- Institut de Biologie de l'Ecole Normale Supérieure, CNRS, Inserm, Paris, France
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42
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Scharf A, Pohl F, Egan BM, Kocsisova Z, Kornfeld K. Reproductive Aging in Caenorhabditis elegans: From Molecules to Ecology. Front Cell Dev Biol 2021; 9:718522. [PMID: 34604218 PMCID: PMC8481778 DOI: 10.3389/fcell.2021.718522] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Accepted: 08/04/2021] [Indexed: 11/13/2022] Open
Abstract
Aging animals display a broad range of progressive degenerative changes, and one of the most fascinating is the decline of female reproductive function. In the model organism Caenorhabditis elegans, hermaphrodites reach a peak of progeny production on day 2 of adulthood and then display a rapid decline; progeny production typically ends by day 8 of adulthood. Since animals typically survive until day 15 of adulthood, there is a substantial post reproductive lifespan. Here we review the molecular and cellular changes that occur during reproductive aging, including reductions in stem cell number and activity, slowing meiotic progression, diminished Notch signaling, and deterioration of germ line and oocyte morphology. Several interventions have been identified that delay reproductive aging, including mutations, drugs and environmental factors such as temperature. The detailed description of reproductive aging coupled with interventions that delay this process have made C. elegans a leading model system to understand the mechanisms that drive reproductive aging. While reproductive aging has dramatic consequences for individual fertility, it also has consequences for the ecology of the population. Population dynamics are driven by birth and death, and reproductive aging is one important factor that influences birth rate. A variety of theories have been advanced to explain why reproductive aging occurs and how it has been sculpted during evolution. Here we summarize these theories and discuss the utility of C. elegans for testing mechanistic and evolutionary models of reproductive aging.
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Affiliation(s)
- Andrea Scharf
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, MO, United States
| | - Franziska Pohl
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, MO, United States.,Department of Medicine, Washington University School of Medicine, St. Louis, MO, United States
| | - Brian M Egan
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, MO, United States
| | - Zuzana Kocsisova
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, MO, United States
| | - Kerry Kornfeld
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, MO, United States
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Byrd DT, Jin Y. Wired for insight-recent advances in Caenorhabditis elegans neural circuits. Curr Opin Neurobiol 2021; 69:159-169. [PMID: 33957432 PMCID: PMC8387325 DOI: 10.1016/j.conb.2021.02.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Revised: 02/16/2021] [Accepted: 02/22/2021] [Indexed: 11/15/2022]
Abstract
The completion of Caenorhabditis elegans connectomics four decades ago has long guided mechanistic investigation of neuronal circuits. Recent technological advances in microscopy and computation programs have aided re-examination of this connectomics, expanding our knowledge by both uncovering previously unreported synaptic connections and also generating models for neural networks underlying behaviors. Combining molecular information from single cell transcriptomes with elegant tools for cell-specific manipulation has further enhanced the ability to precisely investigate individual neurons in behaving animals. This mini-review aims to provide an overview of new information on connectomics and progress toward a molecular atlas of C. elegans nervous system, and discuss emerging findings on neuronal circuits.
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Affiliation(s)
- Dana T Byrd
- Neurobiology Section, University of California San Diego, La Jolla, CA, 92093, USA.
| | - Yishi Jin
- Neurobiology Section, University of California San Diego, La Jolla, CA, 92093, USA; Kavli Institute of Brain and Mind, University of California San Diego, La Jolla, CA, 92093, USA.
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Pees B, Yang W, Kloock A, Petersen C, Peters L, Fan L, Friedrichsen M, Butze S, Zárate-Potes A, Schulenburg H, Dierking K. Effector and regulator: Diverse functions of C. elegans C-type lectin-like domain proteins. PLoS Pathog 2021; 17:e1009454. [PMID: 33793670 PMCID: PMC8051790 DOI: 10.1371/journal.ppat.1009454] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2020] [Revised: 04/16/2021] [Accepted: 03/05/2021] [Indexed: 11/22/2022] Open
Abstract
In C. elegans, 283 clec genes encode a highly diverse family of C-type lectin-like domain (CTLD) proteins. Since vertebrate CTLD proteins have characterized functions in defense responses against pathogens and since expression of C. elegans clec genes is pathogen-dependent, it is generally assumed that clec genes function in C. elegans immune defenses. However, little is known about the relative contribution and exact function of CLEC proteins in C. elegans immunity. Here, we focused on the C. elegans clec gene clec-4, whose expression is highly upregulated by pathogen infection, and its paralogs clec-41 and clec-42. We found that, while mutation of clec-4 resulted in enhanced resistance to the Gram-positive pathogen Bacillus thuringiensis MYBt18247 (Bt247), inactivation of clec-41 and clec-42 by RNAi enhanced susceptibility to Bt247. Further analyses revealed that enhanced resistance of clec-4 mutants to Bt247 was due to an increase in feeding cessation on the pathogen and consequently a decrease in pathogen load. Moreover, clec-4 mutants exhibited feeding deficits also on non-pathogenic bacteria that were in part reflected in the clec-4 gene expression profile, which overlapped with gene sets affected by starvation or mutation in nutrient sensing pathways. However, loss of CLEC-4 function only mildly affected life-history traits such as fertility, indicating that clec-4 mutants are not subjected to dietary restriction. While CLEC-4 function appears to be associated with the regulation of feeding behavior, we show that CLEC-41 and CLEC-42 proteins likely function as bona fide immune effector proteins that have bacterial binding and antimicrobial capacities. Together, our results exemplify functional diversification within clec gene paralogs. C-type lectin-like domain (CTLD) containing proteins fulfill various and fundamental tasks in the human and mouse immune system. Genes encoding CTLD proteins are present in all animal genomes, in some cases in very large numbers and highly diversified. While the function of several vertebrate CTLD proteins is well characterized, experimental evidence of an immune function of most invertebrate CTLD proteins is missing, although their role in immunity is usually assumed. We here explore the immune function of three related CTLD proteins in the model nematode Caenorhabditis elegans. We find that they play diverse roles in C. elegans immunity, functioning as antimicrobial immune effector proteins that are important for defense against pathogen infection and probably directly interact with bacteria, but also regulators of feeding behavior that more indirectly affect C. elegans pathogen resistance. Such insight into the functional consequence of invertebrate CTLD protein diversification contributes to our understanding of the evolution of innate and invertebrate immune systems.
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Affiliation(s)
- Barbara Pees
- Department of Evolutionary Ecology and Genetics, Christian-Albrechts-Universität zu Kiel, Kiel, Germany
- Department of Comparative Immunobiology, Christian-Albrechts-Universität zu Kiel, Kiel, Germany
| | - Wentao Yang
- Department of Evolutionary Ecology and Genetics, Christian-Albrechts-Universität zu Kiel, Kiel, Germany
| | - Anke Kloock
- Department of Evolutionary Ecology and Genetics, Christian-Albrechts-Universität zu Kiel, Kiel, Germany
| | - Carola Petersen
- Department of Evolutionary Ecology and Genetics, Christian-Albrechts-Universität zu Kiel, Kiel, Germany
- Department of Comparative Immunobiology, Christian-Albrechts-Universität zu Kiel, Kiel, Germany
| | - Lena Peters
- Department of Evolutionary Ecology and Genetics, Christian-Albrechts-Universität zu Kiel, Kiel, Germany
| | - Li Fan
- Department of Evolutionary Ecology and Genetics, Christian-Albrechts-Universität zu Kiel, Kiel, Germany
| | - Meike Friedrichsen
- Department of Evolutionary Ecology and Genetics, Christian-Albrechts-Universität zu Kiel, Kiel, Germany
| | - Sabrina Butze
- Department of Evolutionary Ecology and Genetics, Christian-Albrechts-Universität zu Kiel, Kiel, Germany
| | - Alejandra Zárate-Potes
- Department of Evolutionary Ecology and Genetics, Christian-Albrechts-Universität zu Kiel, Kiel, Germany
| | - Hinrich Schulenburg
- Department of Evolutionary Ecology and Genetics, Christian-Albrechts-Universität zu Kiel, Kiel, Germany
- Max-Planck Institute for Evolutionary Biology, Ploen, Germany
| | - Katja Dierking
- Department of Evolutionary Ecology and Genetics, Christian-Albrechts-Universität zu Kiel, Kiel, Germany
- * E-mail:
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Abstract
Although Caenorhabditis elegans has been used as a model host for studying host-pathogen interactions for more than 20 years, the mechanisms by which it identifies pathogens are not well understood. This is largely due to its lack of most known pattern recognition receptors (PRRs) that recognize pathogen-derived molecules. Recent behavioral research in C. elegans indicates that its nervous system plays a major role in microbe sensing. With the increasing integration of neurobiology in immunological research, future studies may find that neuronal detection of pathogens is an integral part of C. elegans-pathogen interactions. Similar to that of mammals, the C. elegans nervous system regulates its immune system to maintain immunological homeostasis. Studies in the nematode have revealed unprecedented details regarding the molecules, cells, and signaling pathways involved in neural regulation of immunity. Notably, some of the studies indicate that some neuroimmune regulatory circuits need not be "activated" by pathogen infection because they are tonically active and that there could be a predetermined set point for internal immunity, around which the nervous system adjusts immune responses to internal or external environmental changes. Here, we review recent progress on the roles of the C. elegans nervous system in pathogen detection and immune regulation. Because of its advantageous characteristics, we expect that the C. elegans model will be critical for deciphering complex neuroimmune signaling mechanisms that integrate and process multiple sensory cues.
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Affiliation(s)
- Yiyong Liu
- Department of Biomedical Sciences, Elson S. Floyd College of Medicine, Washington State University, Spokane, Washington, USA
- Genomics Core, Washington State University, Spokane, Washington, USA
| | - Jingru Sun
- Department of Biomedical Sciences, Elson S. Floyd College of Medicine, Washington State University, Spokane, Washington, USA
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Gamalero E, Glick BR. The Use of Plant Growth-Promoting Bacteria to Prevent Nematode Damage to Plants. BIOLOGY 2020; 9:biology9110381. [PMID: 33171782 PMCID: PMC7695023 DOI: 10.3390/biology9110381] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/18/2020] [Revised: 10/31/2020] [Accepted: 11/04/2020] [Indexed: 01/17/2023]
Abstract
Simple Summary It has been estimated that 100 g of bulk soil can host about 2000–4000 nematodes and this amount is increased 5-fold in the rhizosphere. A certain number of these nematodes are pathogenic for plants and cause yield and economic losses. Application of chemical nematicides is the most common method used to reduce nematode populations, but these chemicals can have a negative impact on both the environment and human health. Therefore, other more environmentally friendly methods of suppression of plant-parasitic nematodes have been proposed. Among them, the use of plant beneficial soil bacteria, behaving as biocontrol agents against nematodes, represent a potential alternative to chemicals. Abstract Plant-parasitic nematodes have been estimated to annually cause around US $173 billion in damage to plant crops worldwide. Moreover, with global climate change, it has been suggested that the damage to crops from nematodes is likely to increase in the future. Currently, a variety of potentially dangerous and toxic chemical agents are used to limit the damage to crops by plant-parasitic nematodes. As an alternative to chemicals and a more environmentally friendly means of decreasing nematode damage to plants, researchers have begun to examine the possible use of various soil bacteria, including plant growth-promoting bacteria (PGPB). Here, the current literature on some of the major mechanisms employed by these soil bacteria is examined. It is expected that within the next 5–10 years, as scientists continue to elaborate the mechanisms used by these bacteria, biocontrol soil bacteria will gradually replace the use of chemicals as nematicides.
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Affiliation(s)
- Elisa Gamalero
- Dipartimento di Scienze e Innovazione Tecnologica, Università del Piemonte Orientale, Viale T. Michel 11, 15121 Alessandria, Italy
- Correspondence: ; Tel.: +39-0131-360238
| | - Bernard R. Glick
- Department of Biology, University of Waterloo, Waterloo, ON N2L 3G1, Canada;
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Abstract
With a nervous system that has only a few hundred neurons, Caenorhabditis elegans was initially not regarded as a model for studies on learning. However, the collective effort of the C. elegans field in the past several decades has shown that the worm displays plasticity in its behavioral response to a wide range of sensory cues in the environment. As a bacteria-feeding worm, C. elegans is highly adaptive to the bacteria enriched in its habitat, especially those that are pathogenic and pose a threat to survival. It uses several common forms of behavioral plasticity that last for different amounts of time, including imprinting and adult-stage associative learning, to modulate its interactions with pathogenic bacteria. Probing the molecular, cellular and circuit mechanisms underlying these forms of experience-dependent plasticity has identified signaling pathways and regulatory insights that are conserved in more complex animals.
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Affiliation(s)
- He Liu
- Department of Organismic and Evolutionary Biology, Center for Brain Science, Harvard University, Cambridge, MA, USA
| | - Yun Zhang
- Department of Organismic and Evolutionary Biology, Center for Brain Science, Harvard University, Cambridge, MA, USA
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Alcedo J, Prahlad V. Neuromodulators: an essential part of survival. J Neurogenet 2020; 34:475-481. [PMID: 33170042 PMCID: PMC7811185 DOI: 10.1080/01677063.2020.1839066] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Accepted: 10/15/2020] [Indexed: 10/23/2022]
Abstract
The coordination between the animal's external environment and internal state requires constant modulation by chemicals known as neuromodulators. Neuromodulators, such as biogenic amines, neuropeptides and cytokines, promote organismal homeostasis. Over the past several decades, Caenorhabditiselegans has grown into a powerful model organism that allows the elucidation of the mechanisms of action of neuromodulators that are conserved across species. In this perspective, we highlight a collection of articles in this issue that describe how neuromodulators optimize C. elegans survival.
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Affiliation(s)
- Joy Alcedo
- Department of Biological Sciences, Wayne State University, Detroit, MI, USA
| | - Veena Prahlad
- Department of Biology, Aging Mind and Brain Initiative, and Iowa Neuroscience Institute, University of Iowa, Iowa City, IA, USA
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