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Troha K, Ayres JS. Cooperative defenses during enteropathogenic infection. Curr Opin Microbiol 2022; 65:123-130. [PMID: 34847524 PMCID: PMC8818259 DOI: 10.1016/j.mib.2021.11.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Revised: 11/09/2021] [Accepted: 11/09/2021] [Indexed: 02/03/2023]
Abstract
During their co-evolution with pathogens, hosts acquired defensive health strategies that allow them to maintain their health or promote recovery when challenged with infections. The cooperative defense system is a largely unexplored branch of these evolved defense strategies. Cooperative defenses limit physiological damage and promote health without having a negative impact on a pathogen's ability to survive and replicate within the host. Here, we review recent discoveries in the new field of cooperative defenses using the model pathogens Citrobacter rodentium and Salmonella enterica. We discuss not only host-encoded but also pathogen-encoded mechanisms of cooperative defenses. Cooperative defenses remain an untapped resource in clinical medicine. With a global pandemic exacerbated by a lack of vaccine access and a worldwide rise in antibiotic resistance, the study of cooperative defenses offers an opportunity to safeguard health in the face of pathogenic infection.
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Affiliation(s)
- Katia Troha
- Molecular and Systems Physiology Lab, Gene Expression Lab, Nomis Center for Immunobiology and Microbial Pathogenesis, Salk Institute for Biological Studies, 10010 N. Torrey Pines Road, La Jolla, CA 92037, USA
| | - Janelle S. Ayres
- Molecular and Systems Physiology Lab, Gene Expression Lab, Nomis Center for Immunobiology and Microbial Pathogenesis, Salk Institute for Biological Studies, 10010 N. Torrey Pines Road, La Jolla, CA 92037, USA,Correspondence:
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Abstract
Metabolism is one of the strongest drivers of interkingdom interactions—including those between microorganisms and their multicellular hosts. Traditionally thought to fuel energy requirements and provide building blocks for biosynthetic pathways, metabolism is now appreciated for its role in providing metabolites, small-molecule intermediates generated from metabolic processes, to perform various regulatory functions to mediate symbiotic relationships between microbes and their hosts. Here, we review recent advances in our mechanistic understanding of how microbiota-derived metabolites orchestrate and support physiological responses in the host, including immunity, inflammation, defense against infections, and metabolism. Understanding how microbes metabolically communicate with their hosts will provide us an opportunity to better describe how a host interacts with all microbes—beneficial, pathogenic, and commensal—and an opportunity to discover new ways to treat microbial-driven diseases.
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Affiliation(s)
- Justin L. McCarville
- Molecular and Systems Physiology Laboratory, Gene Expression Laboratory, NOMIS Center for Immunobiology and Microbial Pathogenesis, Salk Institute for Biological Studies, La Jolla, California 92037, USA
| | - Grischa Y. Chen
- Molecular and Systems Physiology Laboratory, Gene Expression Laboratory, NOMIS Center for Immunobiology and Microbial Pathogenesis, Salk Institute for Biological Studies, La Jolla, California 92037, USA
| | - Víctor D. Cuevas
- Molecular and Systems Physiology Laboratory, Gene Expression Laboratory, NOMIS Center for Immunobiology and Microbial Pathogenesis, Salk Institute for Biological Studies, La Jolla, California 92037, USA
| | - Katia Troha
- Molecular and Systems Physiology Laboratory, Gene Expression Laboratory, NOMIS Center for Immunobiology and Microbial Pathogenesis, Salk Institute for Biological Studies, La Jolla, California 92037, USA
| | - Janelle S. Ayres
- Molecular and Systems Physiology Laboratory, Gene Expression Laboratory, NOMIS Center for Immunobiology and Microbial Pathogenesis, Salk Institute for Biological Studies, La Jolla, California 92037, USA
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Troha K, Ayres JS. Metabolic Adaptations to Infections at the Organismal Level. Trends Immunol 2020; 41:113-125. [PMID: 31959515 DOI: 10.1016/j.it.2019.12.001] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2019] [Revised: 12/08/2019] [Accepted: 12/08/2019] [Indexed: 02/07/2023]
Abstract
Metabolic processes occurring during host-microbiota-pathogen interactions can favorably or negatively influence host survival during infection. Defining the metabolic needs of the three players, the mechanisms through which they acquire nutrients, and whether each participant cooperates or competes with each other to meet their own metabolic demands during infection has the potential to reveal new approaches to treat disease. Here, we review topical findings in organismal metabolism and infection and highlight four emerging lines of investigation: how host-microbiota metabolic partnerships protect against infection; competition for glucose between host and pathogen; significance of infection-induced anorexia; and redefinition of the role of iron during infection. We also discuss how these discoveries shape our understanding of infection biology and their likely therapeutic value.
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Affiliation(s)
- Katia Troha
- Molecular and Systems Physiology Laboratory, Gene Expression Laboratory, Nomis Center for Immunobiology and Microbial Pathogenesis, Salk Institute for Biological Studies, La Jolla, CA 92037, USA
| | - Janelle S Ayres
- Molecular and Systems Physiology Laboratory, Gene Expression Laboratory, Nomis Center for Immunobiology and Microbial Pathogenesis, Salk Institute for Biological Studies, La Jolla, CA 92037, USA.
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Troha K, Nagy P, Pivovar A, Lazzaro BP, Hartley PS, Buchon N. Nephrocytes Remove Microbiota-Derived Peptidoglycan from Systemic Circulation to Maintain Immune Homeostasis. Immunity 2019; 51:625-637.e3. [DOI: 10.1016/j.immuni.2019.08.020] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2018] [Revised: 05/14/2019] [Accepted: 08/27/2019] [Indexed: 10/25/2022]
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Troha K, Buchon N. Methods for the study of innate immunity in Drosophila melanogaster. Wiley Interdiscip Rev Dev Biol 2019; 8:e344. [PMID: 30993906 DOI: 10.1002/wdev.344] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Revised: 02/25/2019] [Accepted: 03/20/2019] [Indexed: 12/12/2022]
Abstract
From flies to humans, many components of the innate immune system have been conserved during metazoan evolution. This foundational observation has allowed us to develop Drosophila melanogaster, the fruit fly, into a powerful model to study innate immunity in animals. Thanks to an ever-growing arsenal of genetic tools, an easily manipulated genome, and its winning disposition, Drosophila is now employed to study not only basic molecular mechanisms of pathogen recognition and immune signaling, but also the nature of physiological responses activated in the host by microbial challenge and how dysregulation of these processes contributes to disease. Here, we present a collection of methods and protocols to challenge the fly with an assortment of microbes, both systemically and orally, and assess its humoral, cellular, and epithelial response to infection. Our review covers techniques for measuring the reaction to microbial infection both qualitatively and quantitatively. Specifically, we describe survival, bacterial load, BLUD (a measure of disease tolerance), phagocytosis, melanization, clotting, and ROS production assays, as well as efficient protocols to collect hemolymph and measure immune gene expression. We also offer an updated catalog of online resources and a collection of popular reporter lines and mutants to facilitate research efforts. This article is categorized under: Technologies > Analysis of Cell, Tissue, and Animal Phenotypes.
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Affiliation(s)
- Katia Troha
- Department of Entomology, Cornell Institute of Host-Microbe Interactions and Disease, Cornell University, Ithaca, New York
| | - Nicolas Buchon
- Department of Entomology, Cornell Institute of Host-Microbe Interactions and Disease, Cornell University, Ithaca, New York
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Troha K, Im JH, Revah J, Lazzaro BP, Buchon N. Comparative transcriptomics reveals CrebA as a novel regulator of infection tolerance in D. melanogaster. PLoS Pathog 2018; 14:e1006847. [PMID: 29394281 PMCID: PMC5812652 DOI: 10.1371/journal.ppat.1006847] [Citation(s) in RCA: 68] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Revised: 02/14/2018] [Accepted: 01/01/2018] [Indexed: 12/15/2022] Open
Abstract
Host responses to infection encompass many processes in addition to activation of the immune system, including metabolic adaptations, stress responses, tissue repair, and other reactions. The response to bacterial infection in Drosophila melanogaster has been classically described in studies that focused on the immune response elicited by a small set of largely avirulent microbes. Thus, we have surprisingly limited knowledge of responses to infection that are outside the canonical immune response, of how the response to pathogenic infection differs from that to avirulent bacteria, or even of how generic the response to various microbes is and what regulates that core response. In this study, we addressed these questions by profiling the D. melanogaster transcriptomic response to 10 bacteria that span the spectrum of virulence. We found that each bacterium triggers a unique transcriptional response, with distinct genes making up to one third of the response elicited by highly virulent bacteria. We also identified a core set of 252 genes that are differentially expressed in response to the majority of bacteria tested. Among these, we determined that the transcription factor CrebA is a novel regulator of infection tolerance. Knock-down of CrebA significantly increased mortality from microbial infection without any concomitant change in bacterial number. Upon infection, CrebA is upregulated by both the Toll and Imd pathways in the fat body, where it is required to induce the expression of secretory pathway genes. Loss of CrebA during infection triggered endoplasmic reticulum (ER) stress and activated the unfolded protein response (UPR), which contributed to infection-induced mortality. Altogether, our study reveals essential features of the response to bacterial infection and elucidates the function of a novel regulator of infection tolerance.
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Affiliation(s)
- Katia Troha
- Cornell Institute of Host-Microbe Interactions and Disease, Department of Entomology, Cornell University, Ithaca, New York, United States of America
| | - Joo Hyun Im
- Cornell Institute of Host-Microbe Interactions and Disease, Department of Entomology, Cornell University, Ithaca, New York, United States of America
| | - Jonathan Revah
- Cornell Institute of Host-Microbe Interactions and Disease, Department of Entomology, Cornell University, Ithaca, New York, United States of America
| | - Brian P. Lazzaro
- Cornell Institute of Host-Microbe Interactions and Disease, Department of Entomology, Cornell University, Ithaca, New York, United States of America
| | - Nicolas Buchon
- Cornell Institute of Host-Microbe Interactions and Disease, Department of Entomology, Cornell University, Ithaca, New York, United States of America
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Guillou A, Troha K, Wang H, Franc NC, Buchon N. The Drosophila CD36 Homologue croquemort Is Required to Maintain Immune and Gut Homeostasis during Development and Aging. PLoS Pathog 2016; 12:e1005961. [PMID: 27780230 PMCID: PMC5079587 DOI: 10.1371/journal.ppat.1005961] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2016] [Accepted: 09/29/2016] [Indexed: 12/11/2022] Open
Abstract
Phagocytosis is an ancient mechanism central to both tissue homeostasis and immune defense. Both the identity of the receptors that mediate bacterial phagocytosis and the nature of the interactions between phagocytosis and other defense mechanisms remain elusive. Here, we report that Croquemort (Crq), a Drosophila member of the CD36 family of scavenger receptors, is required for microbial phagocytosis and efficient bacterial clearance. Flies mutant for crq are susceptible to environmental microbes during development and succumb to a variety of microbial infections as adults. Crq acts parallel to the Toll and Imd pathways to eliminate bacteria via phagocytosis. crq mutant flies exhibit enhanced and prolonged immune and cytokine induction accompanied by premature gut dysplasia and decreased lifespan. The chronic state of immune activation in crq mutant flies is further regulated by negative regulators of the Imd pathway. Altogether, our data demonstrate that Crq plays a key role in maintaining immune and organismal homeostasis.
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Affiliation(s)
- Aurélien Guillou
- Department of Entomology, Cornell University, Ithaca, NY, United States Of America
| | - Katia Troha
- Department of Entomology, Cornell University, Ithaca, NY, United States Of America
| | - Hui Wang
- Department of Cell & Molecular Biology, The Scripps Research Institute, La Jolla, CA, United States Of America
| | - Nathalie C. Franc
- Department of Cell & Molecular Biology, The Scripps Research Institute, La Jolla, CA, United States Of America
| | - Nicolas Buchon
- Department of Entomology, Cornell University, Ithaca, NY, United States Of America
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