1
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Ortjohann M, Leippe M. Molecular characterization of two newly recognized lysozymes of the protist Dictyostelium discoideum. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2025; 164:105334. [PMID: 39909204 DOI: 10.1016/j.dci.2025.105334] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2025] [Revised: 01/23/2025] [Accepted: 02/02/2025] [Indexed: 02/07/2025]
Abstract
The model organism Dictyostelium discoideum functions as a social amoeba that can aggregate, eventually forming a fruiting body composed of a fixed number of cells. This behavior requires a soluble counting factor (CF) complex, which plays a key role in group size determination and has been identified earlier. The CF complex comprises among others the proteins CF45-1 and CF50. Although both proteins share sequence similarities with characterized Chalaropsis- and Entamoeba-type lysozymes, enzymatic activity has not been confirmed until now. CF lysozymes have unusual sequence characteristics consisting of an N-terminal glycoside hydrolase family 25 (GH25) domain and a C-terminal low-complexity region rich in serine, glycine, alanine, and asparagine residues. In this study, we present the production and purification of soluble recombinant CF lysozymes and demonstrate notable enzymatic activity, in particular for CF50. Additionally, a truncated version of CF50, which lacks the C-terminal low-complexity region, displayed significantly enhanced lysozyme activity compared to the entire enzyme. Both CF lysozymes exerted strict pH dependence with maximal activity observed under acidic conditions at pH 3.0-3.5. Moreover, the enzymes displayed highest activity at low ionic strengths and were stable at relatively low temperatures only. Using structural modeling and site-directed mutagenesis, we identified a glutamic acid residue essential for catalysis. Conclusively, we propose a neighboring group catalytic mechanism analogous to that of other GH25 lysozymes.
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Affiliation(s)
- Marius Ortjohann
- Comparative Immunobiology, Zoological Institute, Christian-Albrechts-Universität Kiel, Am Botanischen Garten 1-9, D-24118, Kiel, Germany
| | - Matthias Leippe
- Comparative Immunobiology, Zoological Institute, Christian-Albrechts-Universität Kiel, Am Botanischen Garten 1-9, D-24118, Kiel, Germany.
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2
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Ortjohann M, Leippe M. Molecular Characterization of Ancient Prosaposin-like Proteins from the Protist Dictyostelium discoideum. Biochemistry 2024; 63:2768-2777. [PMID: 39421968 PMCID: PMC11542183 DOI: 10.1021/acs.biochem.4c00479] [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: 08/17/2024] [Revised: 10/09/2024] [Accepted: 10/09/2024] [Indexed: 10/19/2024]
Abstract
To combat the permanent exposure to potential pathogens every organism relies on an immune system. Important factors in innate immunity are antimicrobial peptides (AMPs) that are structurally highly diverse. Some AMPs are known to belong to the saposin-like proteins (SAPLIPs), a group of polypeptides with a broad functional spectrum. The model organism Dictyostelium discoideum possesses a remarkably large arsenal of potential SAPLIPs, which are termed amoebapore-like peptides (Apls), but the knowledge about these proteins is very limited. Here, we report about the biochemical characterization of AplE1, AplE2, AplK1, and AplK2, which are derived from the two precursor proteins AplE and AplK, thereby resembling prosaposins of vertebrates. We produced these Apls as recombinant polypeptides in Escherichia coli using a self-splicing intein to remove an affinity tag used for purification. All recombinant Apls exhibited pore-forming activity in a pH-dependent manner, as evidenced by liposome depolarization, showing higher activities the more acidic the setting was. Lipid preference was detected for negatively charged phospholipids and in particular for cardiolipin. Antimicrobial activity against various bacteria was found to be inferior in classical microdilution assays. However, all of the Apls studied permeabilized the cytoplasmic membrane of live Bacillus subtilis. Collectively, we assume that the selected Apls interact by their cationic charge with negatively charged bacterial membranes in acidic environments such as phagolysosomes and eventually lyse the target cells by pore formation.
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Affiliation(s)
- Marius Ortjohann
- Comparative Immunobiology,
Zoological Institute, Christian-Albrechts-Universität
Kiel, Am Botanischen Garten 1-9, D-24118 Kiel, Germany
| | - Matthias Leippe
- Comparative Immunobiology,
Zoological Institute, Christian-Albrechts-Universität
Kiel, Am Botanischen Garten 1-9, D-24118 Kiel, Germany
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3
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Herb M, Schatz V, Hadrian K, Hos D, Holoborodko B, Jantsch J, Brigo N. Macrophage variants in laboratory research: most are well done, but some are RAW. Front Cell Infect Microbiol 2024; 14:1457323. [PMID: 39445217 PMCID: PMC11496307 DOI: 10.3389/fcimb.2024.1457323] [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: 06/30/2024] [Accepted: 09/06/2024] [Indexed: 10/25/2024] Open
Abstract
Macrophages play a pivotal role in the innate immune response. While their most characteristic function is phagocytosis, it is important not to solely characterize macrophages by this activity. Their crucial roles in body development, homeostasis, repair, and immune responses against pathogens necessitate a broader understanding. Macrophages exhibit remarkable plasticity, allowing them to modify their functional characteristics in response to the tissue microenvironment (tissue type, presence of pathogens or inflammation, and specific signals from neighboring cells) swiftly. While there is no single defined "macrophage" entity, there is a diverse array of macrophage types because macrophage ontogeny involves the differentiation of progenitor cells into tissue-resident macrophages, as well as the recruitment and differentiation of circulating monocytes in response to tissue-specific cues. In addition, macrophages continuously sense and respond to environmental cues and tissue conditions, adjusting their functional and metabolic states accordingly. Consequently, it is of paramount importance to comprehend the heterogeneous origins and functions of macrophages employed in in vitro studies, as each available in vitro macrophage model is associated with specific sets of strengths and limitations. This review centers its attention on a comprehensive comparison between immortalized mouse macrophage cell lines and primary mouse macrophages. It provides a detailed analysis of the strengths and weaknesses inherent in these in vitro models. Finally, it explores the subtle distinctions between diverse macrophage cell lines, offering insights into numerous factors beyond the model type that can profoundly influence macrophage function.
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Affiliation(s)
- Marc Herb
- Institute for Medical Microbiology, Immunology and Hygiene, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany
| | - Valentin Schatz
- Institute for Medical Microbiology, Immunology and Hygiene, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany
| | - Karina Hadrian
- Department of Ophthalmology, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany
| | - Deniz Hos
- Department of Ophthalmology, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany
| | - Bohdan Holoborodko
- Institute of Clinical Microbiology and Hygiene, University Hospital Regensburg and University of Regensburg, Regensburg, Germany
| | - Jonathan Jantsch
- Institute for Medical Microbiology, Immunology and Hygiene, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany
| | - Natascha Brigo
- Institute for Medical Microbiology, Immunology and Hygiene, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany
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4
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Shirokawa Y. Evolutionary stability of developmental commitment. Biosystems 2024; 244:105309. [PMID: 39151881 DOI: 10.1016/j.biosystems.2024.105309] [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: 07/08/2024] [Revised: 08/12/2024] [Accepted: 08/13/2024] [Indexed: 08/19/2024]
Abstract
Evolution of unicellular to multicellular organisms must resolve conflicts in reproductive interests between individual cells and the group. The social amoeba Dictyostelium discoideum is a soil-living eukaryote with facultative sociality. While cells grow in the presence of nutrients, cells aggregate under starvation to form fruiting bodies containing spores and altruistic stalk cells. Once cells socially committed, they complete formation of fruiting bodies, even if a new source of nutrients becomes available. The persistence of this social commitment raises questions as it inhibits individual cells from swiftly returning to solitary growth. I hypothesize that traits enabling premature de-commitment are hindered from being selected. Recent work has revealed outcomes of the premature de-commitment through forced refeeding; The de-committed cells take an altruistic prestalk-like position due to their reduced cohesiveness through interactions with socially committed cells. I constructed an evolutionary model assuming their division of labor. The results revealed a valley in the fitness landscape that prevented invasion of de-committing mutants, indicating evolutionary stability of the social commitment. The findings provide a general scheme that maintains multicellularity by evolving a specific division of labor, in which less cohesive individuals become altruists.
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Affiliation(s)
- Yuka Shirokawa
- Graduate School of Arts and Sciences, University of Tokyo, 3-8-1 Komaba, Meguro-ku, Tokyo, 153-8902, Japan.
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5
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Scott TJ, Queller DC, Strassmann JE. Complex third-party effects in the Dictyostelium-Paraburkholderia symbiosis: prey bacteria that are eaten, carried or left behind. Proc Biol Sci 2024; 291:20241111. [PMID: 39016123 PMCID: PMC11253208 DOI: 10.1098/rspb.2024.1111] [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: 01/08/2024] [Revised: 06/13/2024] [Accepted: 06/18/2024] [Indexed: 07/18/2024] Open
Abstract
Symbiotic interactions may change depending on third parties like predators or prey. Third-party interactions with prey bacteria are central to the symbiosis between Dictyostelium discoideum social amoeba hosts and Paraburkholderia bacterial symbionts. Symbiosis with inedible Paraburkholderia allows host D. discoideum to carry prey bacteria through the dispersal stage where hosts aggregate and develop into fruiting bodies that disperse spores. Carrying prey bacteria benefits hosts when prey are scarce but harms hosts when prey bacteria are plentiful, possibly because hosts leave some prey bacteria behind while carrying. Thus, understanding benefits and costs in this symbiosis requires measuring how many prey bacteria are eaten, carried and left behind by infected hosts. We found that Paraburkholderia infection makes hosts leave behind both symbionts and prey bacteria. However, the number of prey bacteria left uneaten was too small to explain why infected hosts produced fewer spores than uninfected hosts. Turning to carried bacteria, we found that hosts carry prey bacteria more often after developing in prey-poor environments than in prey-rich ones. This suggests that carriage is actively modified to ensure hosts have prey in the harshest conditions. Our results show that multi-faceted interactions with third parties shape the evolution of symbioses in complex ways.
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Affiliation(s)
- Trey J. Scott
- Department of Biology, Washington University, St. Louis, MO63130, USA
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA02138, USA
| | - David C. Queller
- Department of Biology, Washington University, St. Louis, MO63130, USA
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6
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Guallar-Garrido S, Soldati T. Exploring host-pathogen interactions in the Dictyostelium discoideum-Mycobacterium marinum infection model of tuberculosis. Dis Model Mech 2024; 17:dmm050698. [PMID: 39037280 PMCID: PMC11552500 DOI: 10.1242/dmm.050698] [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: 07/23/2024] Open
Abstract
Mycobacterium tuberculosis is a pathogenic mycobacterium that causes tuberculosis. Tuberculosis is a significant global health concern that poses numerous clinical challenges, particularly in terms of finding effective treatments for patients. Throughout evolution, host immune cells have developed cell-autonomous defence strategies to restrain and eliminate mycobacteria. Concurrently, mycobacteria have evolved an array of virulence factors to counteract these host defences, resulting in a dynamic interaction between host and pathogen. Here, we review recent findings, including those arising from the use of the amoeba Dictyostelium discoideum as a model to investigate key mycobacterial infection pathways. D. discoideum serves as a scalable and genetically tractable model for human phagocytes, providing valuable insights into the intricate mechanisms of host-pathogen interactions. We also highlight certain similarities between M. tuberculosis and Mycobacterium marinum, and the use of M. marinum to more safely investigate mycobacteria in D. discoideum.
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Affiliation(s)
- Sandra Guallar-Garrido
- Department of Biochemistry, Faculty of Science, University of Geneva, 30 quai Ernest-Ansermet, Science II, 1211 Geneva-4, Switzerland
| | - Thierry Soldati
- Department of Biochemistry, Faculty of Science, University of Geneva, 30 quai Ernest-Ansermet, Science II, 1211 Geneva-4, Switzerland
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7
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Shirokawa Y, Shimada M, Shimada N, Sawai S. Prestalk-like positioning of de-differentiated cells in the social amoeba Dictyostelium discoideum. Sci Rep 2024; 14:7677. [PMID: 38561423 PMCID: PMC10985001 DOI: 10.1038/s41598-024-58277-3] [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: 02/01/2024] [Accepted: 03/27/2024] [Indexed: 04/04/2024] Open
Abstract
The social amoeba Dictyostelium discoideum switches between solitary growth and social fruitification depending on nutrient availability. Under starvation, cells aggregate and form fruiting bodies consisting of spores and altruistic stalk cells. Once cells socially committed, they complete fruitification, even if a new source of nutrients becomes available. This social commitment is puzzling because it hinders individual cells from resuming solitary growth quickly. One idea posits that traits that facilitate premature de-commitment are hindered from being selected. We studied outcomes of the premature de-commitment through forced refeeding. Our results show that when refed cells interacted with non-refed cells, some of them became solitary, whereas a fraction was redirected to the altruistic stalk, regardless of their original fate. The refed cells exhibited reduced cohesiveness and were sorted out during morphogenesis. Our findings provide an insight into a division of labor of the social amoeba, in which less cohesive individuals become altruists.
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Affiliation(s)
- Yuka Shirokawa
- Graduate School of Arts and Sciences, University of Tokyo, Tokyo, 153-8902, Japan.
| | - Masakazu Shimada
- Graduate School of Arts and Sciences, University of Tokyo, Tokyo, 153-8902, Japan
| | - Nao Shimada
- Graduate School of Arts and Sciences, University of Tokyo, Tokyo, 153-8902, Japan
| | - Satoshi Sawai
- Graduate School of Arts and Sciences, University of Tokyo, Tokyo, 153-8902, Japan
- Research Center for Complex Systems Biology, Universal Biology Institute, University of Tokyo, Tokyo, 153-8902, Japan
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8
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Steele MI, Peiser JM, Shreenidhi PM, Strassmann JE, Queller DC. Predation-resistant Pseudomonas bacteria engage in symbiont-like behavior with the social amoeba Dictyostelium discoideum. THE ISME JOURNAL 2023; 17:2352-2361. [PMID: 37884792 PMCID: PMC10689837 DOI: 10.1038/s41396-023-01535-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Revised: 10/04/2023] [Accepted: 10/06/2023] [Indexed: 10/28/2023]
Abstract
The soil amoeba Dictyostelium discoideum acts as both a predator and potential host for diverse bacteria. We tested fifteen Pseudomonas strains that were isolated from transiently infected wild D. discoideum for ability to escape predation and infect D. discoideum fruiting bodies. Three predation-resistant strains frequently caused extracellular infections of fruiting bodies but were not found within spores. Furthermore, infection by one of these species induces secondary infections and suppresses predation of otherwise edible bacteria. Another strain can persist inside of amoebae after being phagocytosed but is rarely taken up. We sequenced isolate genomes and discovered that predation-resistant isolates are not monophyletic. Many Pseudomonas isolates encode secretion systems and toxins known to improve resistance to phagocytosis in other species, as well as diverse secondary metabolite biosynthetic gene clusters that may contribute to predation resistance. However, the distribution of these genes alone cannot explain why some strains are edible and others are not. Each lineage may employ a unique mechanism for resistance.
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Affiliation(s)
- Margaret I Steele
- Biology Department, Washington University in St. Louis, St. Louis, MO, USA.
| | - Jessica M Peiser
- Biology Department, Washington University in St. Louis, St. Louis, MO, USA
| | - P M Shreenidhi
- Biology Department, Washington University in St. Louis, St. Louis, MO, USA
| | - Joan E Strassmann
- Biology Department, Washington University in St. Louis, St. Louis, MO, USA
| | - David C Queller
- Biology Department, Washington University in St. Louis, St. Louis, MO, USA
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9
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Scott TJ, Larsen TJ, Brock DA, Uhm SYS, Queller DC, Strassmann JE. Symbiotic bacteria, immune-like sentinel cells, and the response to pathogens in a social amoeba. ROYAL SOCIETY OPEN SCIENCE 2023; 10:230727. [PMID: 37593719 PMCID: PMC10427822 DOI: 10.1098/rsos.230727] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/29/2023] [Accepted: 07/27/2023] [Indexed: 08/19/2023]
Abstract
Some endosymbionts living within a host must modulate their hosts' immune systems in order to infect and persist. We studied the effect of a bacterial endosymbiont on a facultatively multicellular social amoeba host. Aggregates of the amoeba Dictyostelium discoideum contain a subpopulation of sentinel cells that function akin to the immune systems of more conventional multicellular organisms. Sentinel cells sequester and discard toxins from D. discoideum aggregates and may play a central role in defence against pathogens. We measured the number and functionality of sentinel cells in aggregates of D. discoideum infected by bacterial endosymbionts in the genus Paraburkholderia. Infected D. discoideum produced fewer and less functional sentinel cells, suggesting that Paraburkholderia may interfere with its host's immune system. Despite impaired sentinel cells, however, infected D. discoideum were less sensitive to ethidium bromide toxicity, suggesting that Paraburkholderia may also have a protective effect on its host. By contrast, D. discoideum infected by Paraburkholderia did not show differences in their sensitivity to two non-symbiotic pathogens. Our results expand previous work on yet another aspect of the complicated relationship between D. discoideum and Paraburkholderia, which has considerable potential as a model for the study of symbiosis.
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Affiliation(s)
- Trey J. Scott
- Department of Biology, Washington University in St. Louis, St. Louis, MO 63130, USA
| | - Tyler J. Larsen
- Department of Biology, Washington University in St. Louis, St. Louis, MO 63130, USA
| | - Debra A. Brock
- Department of Biology, Washington University in St. Louis, St. Louis, MO 63130, USA
| | - So Yeon Stacey Uhm
- Department of Biology, Washington University in St. Louis, St. Louis, MO 63130, USA
| | - David C. Queller
- Department of Biology, Washington University in St. Louis, St. Louis, MO 63130, USA
| | - Joan E. Strassmann
- Department of Biology, Washington University in St. Louis, St. Louis, MO 63130, USA
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Ricci-Tam C, Kuipa S, Kostman MP, Aronson MS, Sgro AE. Microbial models of development: Inspiration for engineering self-assembled synthetic multicellularity. Semin Cell Dev Biol 2023; 141:50-62. [PMID: 35537929 DOI: 10.1016/j.semcdb.2022.04.014] [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: 03/01/2022] [Accepted: 04/13/2022] [Indexed: 10/18/2022]
Abstract
While the field of synthetic developmental biology has traditionally focused on the study of the rich developmental processes seen in metazoan systems, an attractive alternate source of inspiration comes from microbial developmental models. Microbes face unique lifestyle challenges when forming emergent multicellular collectives. As a result, the solutions they employ can inspire the design of novel multicellular systems. In this review, we dissect the strategies employed in multicellular development by two model microbial systems: the cellular slime mold Dictyostelium discoideum and the biofilm-forming bacterium Bacillus subtilis. Both microbes face similar challenges but often have different solutions, both from metazoan systems and from each other, to create emergent multicellularity. These challenges include assembling and sustaining a critical mass of participating individuals to support development, regulating entry into development, and assigning cell fates. The mechanisms these microbial systems exploit to robustly coordinate development under a wide range of conditions offer inspiration for a new toolbox of solutions to the synthetic development community. Additionally, recreating these phenomena synthetically offers a pathway to understanding the key principles underlying how these behaviors are coordinated naturally.
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Affiliation(s)
- Chiara Ricci-Tam
- Department of Biomedical Engineering, Boston University, Boston, MA 02215, USA; Biological Design Center, Boston University, Boston, MA 02215, USA
| | - Sophia Kuipa
- Department of Biomedical Engineering, Boston University, Boston, MA 02215, USA; Biological Design Center, Boston University, Boston, MA 02215, USA
| | - Maya Peters Kostman
- Biological Design Center, Boston University, Boston, MA 02215, USA; Molecular Biology, Cell Biology & Biochemistry Program, Boston University, Boston, MA 02215, USA
| | - Mark S Aronson
- Department of Biomedical Engineering, Boston University, Boston, MA 02215, USA; Biological Design Center, Boston University, Boston, MA 02215, USA
| | - Allyson E Sgro
- Department of Biomedical Engineering, Boston University, Boston, MA 02215, USA; Biological Design Center, Boston University, Boston, MA 02215, USA; Molecular Biology, Cell Biology & Biochemistry Program, Boston University, Boston, MA 02215, USA.
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11
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Rijal R, Ismail I, Jing S, Gomer RH. Starvation Induces Extracellular Accumulation of Polyphosphate in Dictyostelium discoideum to Inhibit Macropinocytosis, Phagocytosis, and Exocytosis. Int J Mol Sci 2023; 24:5923. [PMID: 36982997 PMCID: PMC10056890 DOI: 10.3390/ijms24065923] [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: 02/16/2023] [Revised: 03/10/2023] [Accepted: 03/16/2023] [Indexed: 03/30/2023] Open
Abstract
Dictyostelium discoideum is a soil-dwelling unicellular eukaryote that accumulates extracellular polyphosphate (polyP). At high cell densities, when the cells are about to overgrow their food supply and starve, the corresponding high extracellular concentrations of polyP allow the cells to preemptively anticipate starvation, inhibit proliferation, and prime themselves to begin development. In this report, we show that starved D. discoideum cells accumulate cell surface and extracellular polyP. Starvation reduces macropinocytosis, exocytosis, and phagocytosis, and we find that these effects require the G protein-coupled polyP receptor (GrlD) and two enzymes, Polyphosphate kinase 1 (Ppk1), which is required for synthesizing intracellular polyP, cell surface polyP, and some of the extracellular polyP, and Inositol hexakisphosphate kinase (I6kA), which is required for cell surface polyP and polyP binding to cells, and some of the extracellular polyP. PolyP reduces membrane fluidity, and we find that starvation reduces membrane fluidity; this effect requires GrlD and Ppk1, but not I6kA. Together, these data suggest that in starved cells, extracellular polyP decreases membrane fluidity, possibly as a protective measure. In the starved cells, sensing polyP appears to decrease energy expenditure from ingestion, and decrease exocytosis, and to both decrease energy expenditures and retain nutrients.
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Affiliation(s)
- Ramesh Rijal
- Department of Biology, Texas A&M University, College Station, TX 77843-3474, USA
| | | | | | - Richard H. Gomer
- Department of Biology, Texas A&M University, College Station, TX 77843-3474, USA
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12
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de Lima FMR, Abrahão I, Pentagna N, Carneiro K. Gradual specialization of phagocytic ameboid cells may have impaired regenerative capacities in metazoan lineages. Dev Dyn 2023; 252:343-362. [PMID: 36205096 DOI: 10.1002/dvdy.543] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Revised: 09/20/2022] [Accepted: 09/30/2022] [Indexed: 11/08/2022] Open
Abstract
Animal regeneration is a fascinating field of research that has captured the attention of many generations of scientists. Among the cellular mechanisms underlying tissue and organ regeneration, we highlight the role of phagocytic ameboid cells (PACs). Beyond their ability to engulf nutritional particles, microbes, and apoptotic cells, their involvement in regeneration has been widely documented. It has been extensively described that, at least in part, animal regenerative mechanisms rely on PACs that serve as a hub for a range of critical physiological functions, both in health and disease. Considering the phylogenetics of PAC evolution, and the loss and gain of nutritional, immunological, and regenerative potential across Metazoa, we aim to discuss when and how phagocytic activity was first co-opted to regenerative tissue repair. We propose that the gradual specialization of PACs during metazoan derivation may have contributed to the loss of regenerative potential in animals, with critical impacts on potential translational strategies for regenerative medicine.
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Affiliation(s)
- Felipe Matheus Ribeiro de Lima
- Laboratory of Cellular Proliferation and Differentiation, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
- Developmental Biology, Postgraduate Program in Morphological Sciences, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Isabella Abrahão
- Laboratory of Cellular Proliferation and Differentiation, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Nathalia Pentagna
- Laboratory of Cellular Proliferation and Differentiation, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
- Postgraduate Program in Medicine (Pathological Anatomy), Faculty of Medicine, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Katia Carneiro
- Laboratory of Cellular Proliferation and Differentiation, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
- Developmental Biology, Postgraduate Program in Morphological Sciences, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
- Postgraduate Program in Medicine (Pathological Anatomy), Faculty of Medicine, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
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13
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Rijal R, Ismail I, Jing S, Gomer RH. Starvation induces extracellular accumulation of polyphosphate in Dictyostelium discoideum to inhibit macropinocytosis, phagocytosis, and exocytosis. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.02.16.528874. [PMID: 36824815 PMCID: PMC9949037 DOI: 10.1101/2023.02.16.528874] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/19/2023]
Abstract
Dictyostelium discoideum is a soil-dwelling unicellular eukaryote that accumulates extracellular polyphosphate (polyP). At high cell densities, when the cells are about to overgrow their food supply and starve, the corresponding high extracellular concentrations of polyP allow the cells to preemptively anticipate starvation, inhibit proliferation, and prime themselves to begin development. In this report, we show that starved D. discoideum cells accumulate cell surface and extracellular polyP. Starvation reduces macropinocytosis, exocytosis, and phagocytosis, and we find that these effects require the G protein-coupled polyP receptor (GrlD) and two enzymes, Polyphosphate kinase 1 (Ppk1), which is required for synthesizing intracellular polyP, cell surface polyP, and some of the extracellular polyP, and Inositol hexakisphosphate kinase (I6kA), which is required for cell surface polyP and polyP binding to cells, and some of the extracellular polyP. PolyP reduces membrane fluidity, and we find that starvation reduces membrane fluidity, and this effect requires GrlD and Ppk1 but not I6kA. Together, these data suggest that in starved cells, extracellular polyP decreases membrane fluidity, possibly as a protective measure. In the starved cells, sensing polyP appears to decrease energy expenditure from ingestion, and decrease exocytosis, to both decrease energy expenditures and retain nutrients.
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Dereeper A, Allouch N, Guerlais V, Garnier M, Ma L, De Jonckheere JF, Joseph SJ, Ali IKM, Talarmin A, Marcelino I. Naegleria genus pangenome reveals new structural and functional insights into the versatility of these free-living amoebae. Front Microbiol 2023; 13:1056418. [PMID: 36817109 PMCID: PMC9928731 DOI: 10.3389/fmicb.2022.1056418] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Accepted: 12/21/2022] [Indexed: 02/04/2023] Open
Abstract
Introduction Free-living amoebae of the Naegleria genus belong to the major protist clade Heterolobosea and are ubiquitously distributed in soil and freshwater habitats. Of the 47 Naegleria species described, N. fowleri is the only one being pathogenic to humans, causing a rare but fulminant primary amoebic meningoencephalitis. Some Naegleria genome sequences are publicly available, but the genetic basis for Naegleria diversity and ability to thrive in diverse environments (including human brain) remains unclear. Methods Herein, we constructed a high-quality Naegleria genus pangenome to obtain a comprehensive catalog of genes encoded by these amoebae. For this, we first sequenced, assembled, and annotated six new Naegleria genomes. Results and Discussion Genome architecture analyses revealed that Naegleria may use genome plasticity features such as ploidy/aneuploidy to modulate their behavior in different environments. When comparing 14 near-to-complete genome sequences, our results estimated the theoretical Naegleria pangenome as a closed genome, with 13,943 genes, including 3,563 core and 10,380 accessory genes. The functional annotations revealed that a large fraction of Naegleria genes show significant sequence similarity with those already described in other kingdoms, namely Animalia and Plantae. Comparative analyses highlighted a remarkable genomic heterogeneity, even for closely related strains and demonstrate that Naegleria harbors extensive genome variability, reflected in different metabolic repertoires. If Naegleria core genome was enriched in conserved genes essential for metabolic, regulatory and survival processes, the accessory genome revealed the presence of genes involved in stress response, macromolecule modifications, cell signaling and immune response. Commonly reported N. fowleri virulence-associated genes were present in both core and accessory genomes, suggesting that N. fowleri's ability to infect human brain could be related to its unique species-specific genes (mostly of unknown function) and/or to differential gene expression. The construction of Naegleria first pangenome allowed us to move away from a single reference genome (that does not necessarily represent each species as a whole) and to identify essential and dispensable genes in Naegleria evolution, diversity and biology, paving the way for further genomic and post-genomic studies.
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Affiliation(s)
- Alexis Dereeper
- Institut Pasteur de la Guadeloupe, Unité TReD-Path, Les Abymes, Guadeloupe, France
| | - Nina Allouch
- Institut Pasteur de la Guadeloupe, Unité TReD-Path, Les Abymes, Guadeloupe, France
| | - Vincent Guerlais
- Institut Pasteur de la Guadeloupe, Unité TReD-Path, Les Abymes, Guadeloupe, France
| | - Maëlle Garnier
- Institut Pasteur de la Guadeloupe, Unité TReD-Path, Les Abymes, Guadeloupe, France
| | - Laurence Ma
- Institut Pasteur de Paris, Biomics, Paris, France
| | | | - Sandeep J. Joseph
- Centers for Disease Control and Prevention (CDC), Atlanta, GA, United States
| | - Ibne Karim M. Ali
- Centers for Disease Control and Prevention (CDC), Atlanta, GA, United States
| | - Antoine Talarmin
- Institut Pasteur de la Guadeloupe, Unité TReD-Path, Les Abymes, Guadeloupe, France
| | - Isabel Marcelino
- Institut Pasteur de la Guadeloupe, Unité TReD-Path, Les Abymes, Guadeloupe, France,*Correspondence: Isabel Marcelino,
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15
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Sarkar A, Kumari N, Mukherjee P. The curious case of SARM1: Dr. Jekyll and Mr. Hyde in cell death and immunity? FEBS J 2023; 290:340-358. [PMID: 34710262 DOI: 10.1111/febs.16256] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Revised: 09/21/2021] [Accepted: 10/27/2021] [Indexed: 02/06/2023]
Abstract
Sterile alpha and toll/interleukin-1 receptor motif-containing protein 1 (SARM1) was first identified as a novel ortholog of Drosophila protein CG7915 and was subsequently placed as the fifth member of the human TIR-containing adaptor protein. SARM1 holds a unique position in this family where, unlike other members, it downregulates NFκB activity in response to immunogenic stimulation, interacts with another member of the family, TRIF, to negatively regulate its function, and it also mediates cell death responses. Over the past decade, SARM1 has emerged as one of the primary mediators of programmed axonal degeneration and this robust regulation of axonal degeneration-especially in models of peripheral neuropathy and traumatic injury-makes it an attractive target for therapeutic intervention. The TIR domain of SARM1 possesses an intrinsic NADase activity resulting in cellular energy deficits within the axons, a striking deviation from its other family members of human TLR adaptors. Interestingly, the TIR NADase activity, as seen in SARM1, is also observed in several prokaryotic TIR-containing proteins where they are involved in immune evasion once within the host. Although the immune function of SARM1 is yet to be conclusively discerned, this closeness in function with the prokaryotic TIR-domain containing proteins, places it at an interesting juncture of evolution raising questions about its origin and function in cell death and immunity. In this review, we discuss how a conserved immune adaptor protein like SARM1 switches to a pro-neurodegenerative function and the evolutionarily significance of the process.
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Affiliation(s)
- Ankita Sarkar
- School of Biotechnology, Presidency University, Kolkata, West Bengal, India
| | - Nripa Kumari
- School of Biotechnology, Presidency University, Kolkata, West Bengal, India
| | - Piyali Mukherjee
- School of Biotechnology, Presidency University, Kolkata, West Bengal, India
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16
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Bajgar A, Krejčová G. On the origin of the functional versatility of macrophages. Front Physiol 2023; 14:1128984. [PMID: 36909237 PMCID: PMC9998073 DOI: 10.3389/fphys.2023.1128984] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Accepted: 02/07/2023] [Indexed: 02/25/2023] Open
Abstract
Macrophages represent the most functionally versatile cells in the animal body. In addition to recognizing and destroying pathogens, macrophages remove senescent and exhausted cells, promote wound healing, and govern tissue and metabolic homeostasis. In addition, many specialized populations of tissue-resident macrophages exhibit highly specialized functions essential for the function of specific organs. Sometimes, however, macrophages cease to perform their protective function and their seemingly incomprehensible response to certain stimuli leads to pathology. In this study, we address the question of the origin of the functional versatility of macrophages. To this end, we have searched for the evolutionary origin of macrophages themselves and for the emergence of their characteristic properties. We hypothesize that many of the characteristic features of proinflammatory macrophages evolved in the unicellular ancestors of animals, and that the functional repertoire of macrophage-like amoebocytes further expanded with the evolution of multicellularity and the increasing complexity of tissues and organ systems. We suggest that the entire repertoire of macrophage functions evolved by repurposing and diversification of basic functions that evolved early in the evolution of metazoans under conditions barely comparable to that in tissues of multicellular organisms. We believe that by applying this perspective, we may find an explanation for the otherwise counterintuitive behavior of macrophages in many human pathologies.
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Affiliation(s)
- Adam Bajgar
- Faculty of Science, Department of Molecular Biology and Genetics, University of South Bohemia, Ceske Budejovice, Czechia.,Biology Centre, Institute of Entomology, Academy of Sciences, Ceske Budejovice, Czechia
| | - Gabriela Krejčová
- Faculty of Science, Department of Molecular Biology and Genetics, University of South Bohemia, Ceske Budejovice, Czechia.,Biology Centre, Institute of Entomology, Academy of Sciences, Ceske Budejovice, Czechia
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17
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Gauthier AE, Rotjan RD, Kagan JC. Lipopolysaccharide detection by the innate immune system may be an uncommon defence strategy used in nature. Open Biol 2022; 12:220146. [PMID: 36196535 PMCID: PMC9533005 DOI: 10.1098/rsob.220146] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Accepted: 09/09/2022] [Indexed: 11/12/2022] Open
Abstract
Since the publication of the Janeway's Pattern Recognition hypothesis in 1989, study of pathogen-associated molecular patterns (PAMPs) and their immuno-stimulatory activities has accelerated. Most studies in this area have been conducted in model organisms, which leaves many open questions about the universality of PAMP biology across living systems. Mammals have evolved multiple proteins that operate as receptors for the PAMP lipopolysaccharide (LPS) from Gram-negative bacteria, but LPS is not immuno-stimulatory in all eukaryotes. In this review, we examine the history of LPS as a PAMP in mammals, recent data on LPS structure and its ability to activate mammalian innate immune receptors, and how these activities compare across commonly studied eukaryotes. We discuss why LPS may have evolved to be immuno-stimulatory in some eukaryotes but not others and propose two hypotheses about the evolution of PAMP structure based on the ecology and environmental context of the organism in question. Understanding PAMP structures and stimulatory mechanisms across multi-cellular life will provide insights into the evolutionary origins of innate immunity and may lead to the discovery of new PAMP variations of scientific and therapeutic interest.
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Affiliation(s)
- Anna E. Gauthier
- Division of Gastroenterology, Boston Children's Hospital and Harvard Medical School, 300 Longwood Avenue, Boston, MA 02115, USA
- Program in Virology, Harvard Medical School, Boston, MA, USA
| | - Randi D. Rotjan
- Department of Biology, Boston University, 5 Cummington Mall, Boston, MA 02215, USA
| | - Jonathan C. Kagan
- Division of Gastroenterology, Boston Children's Hospital and Harvard Medical School, 300 Longwood Avenue, Boston, MA 02115, USA
- Harvard Medical School, and Boston Children's Hospital, Division of Immunology, Division of Gastroenterology, USA
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18
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Saito T, Iijima T, Koyama K, Shinagawa T, Yamanaka A, Araki T, Suzuki N, Usuki T, Kay RR. Generating polyketide diversity in Dictyostelium: a Steely hybrid polyketide synthase produces alternate products at different developmental stages. Proc Biol Sci 2022; 289:20221176. [PMID: 36126683 PMCID: PMC9489281 DOI: 10.1098/rspb.2022.1176] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
The soil is a rich ecosystem where many ecological interactions are mediated by small molecules, and in which amoebae are low-level predators and also prey. The social amoeba Dictyostelium discoideum has a high genomic potential for producing polyketides to mediate its ecological interactions, including the unique 'Steely' enzymes, consisting of a fusion between a fatty acid synthase and a chalcone synthase. We report here that D. discoideum further increases its polyketide potential by using the StlB Steely enzyme, and a downstream chlorinating enzyme, to make both a chlorinated signal molecule, DIF-1, during its multi-cellular development, and a set of abundant polyketides in terminally differentiated stalk cells. We identify one of these as a chlorinated dibenzofuran with potent anti-bacterial activity. To do this, StlB switches expression from prespore to stalk cells in late development and is cleaved to release the chalcone synthase domain. Expression of this domain alone in StlB null cells allows synthesis of the stalk-associated, chlorinated polyketides. Thus, by altered expression and processing of StlB, cells make first a signal molecule, and then abundant secondary metabolites, which we speculate help to protect the mature spores from bacterial infection.
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Affiliation(s)
- Tamao Saito
- Faculty of Science and Technology, Sophia University, Tokyo 102-8554, Japan
| | - Tomoyuki Iijima
- Graduate School of Science and Technology, Sophia University, Tokyo 102-8554, Japan
| | - Kohei Koyama
- Graduate School of Science and Technology, Sophia University, Tokyo 102-8554, Japan
| | - Tomonori Shinagawa
- Graduate School of Science and Technology, Sophia University, Tokyo 102-8554, Japan
| | - Ayaka Yamanaka
- Graduate School of Science and Technology, Sophia University, Tokyo 102-8554, Japan
| | - Tsuyoshi Araki
- Faculty of Science and Technology, Sophia University, Tokyo 102-8554, Japan
| | - Noriyuki Suzuki
- Faculty of Science and Technology, Sophia University, Tokyo 102-8554, Japan
| | - Toyonobu Usuki
- Faculty of Science and Technology, Sophia University, Tokyo 102-8554, Japan
| | - Robert R. Kay
- MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, UK
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19
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DuBose JG, Robeson MS, Hoogshagen M, Olsen H, Haselkorn TS. Complexities of Inferring Symbiont Function: Paraburkholderia Symbiont Dynamics in Social Amoeba Populations and Their Impacts on the Amoeba Microbiota. Appl Environ Microbiol 2022; 88:e0128522. [PMID: 36043858 PMCID: PMC9499018 DOI: 10.1128/aem.01285-22] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Accepted: 08/11/2022] [Indexed: 11/20/2022] Open
Abstract
The relationship between the social amoeba Dictyostelium discoideum and its endosymbiotic bacteria Paraburkholderia provides a model system for studying the development of symbiotic relationships. Laboratory experiments have shown that any of three species of the Paraburkholderia symbiont allow D. discoideum food bacteria to persist through the amoeba life cycle and survive in amoeba spores rather than being fully digested. This phenomenon is termed "farming," as it potentially allows spores dispersed to food-poor locations to grow their own. The occurrence and impact of farming in natural populations, however, have been a challenge to measure. Here, we surveyed natural D. discoideum populations and found that only one of the three symbiont species, Paraburkholderia agricolaris, remained prevalent. We then explored the effect of Paraburkholderia on the amoeba microbiota, expecting that by facilitating bacterial food carriage, it would diversify the microbiota. Contrary to our expectations, Paraburkholderia tended to infectiously dominate the D. discoideum microbiota, in some cases decreasing diversity. Similarly, we found little evidence for Paraburkholderia facilitating the carriage of particular food bacteria. These findings highlight the complexities of inferring symbiont function in nature and suggest the possibility that Paraburkholderia could be playing multiple roles for its host. IMPORTANCE The functions of symbionts in natural populations can be difficult to completely discern. The three Paraburkholderia bacterial farming symbionts of the social amoeba Dictyostelium discoideum have been shown in the laboratory environment to allow the amoebas to carry, rather than fully digest, food bacteria. This potentially provides a fitness benefit to the amoebas upon dispersal to food-poor environments, as they could grow their food. We expected that meaningful food carriage would manifest as a more diverse microbiota. Surprisingly, we found that Paraburkholderia tended to infectiously dominate the D. discoideum microbiota rather than diversifying it. We determined that only one of the three Paraburkholderia symbionts has increased in prevalence in natural populations in the past 20 years, suggesting that this symbiont may be beneficial, however. These findings suggest that Paraburkholderia may have an alternative function for its host, which drives its prevalence in natural populations.
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Affiliation(s)
- James G. DuBose
- Department of Biology, University of Central Arkansas, Conway, Arkansas, USA
| | - Michael S. Robeson
- Department of Biomedical Informatics, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA
| | | | - Hunter Olsen
- Department of Biology, University of Central Arkansas, Conway, Arkansas, USA
| | - Tamara S. Haselkorn
- Department of Biology, University of Central Arkansas, Conway, Arkansas, USA
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20
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Abstract
Progress in neuroimmunology established that the nervous and the immune systems are two functionally related physiological systems. Unique sensory and immune receptors enable them to control interactions of the organism with the inner and the outer worlds. Both systems undergo an experience-driven selection process during their ontogeny. They share the same mediators/neurotransmitters and use synapses for intercellular communication. They keep a memory of previous experiences. Immune cells can affect nervous cells, nervous cells can affect immune cells, and they regulate each other. I however argue that the two systems differ by three major points: 1) Unlike the nervous system, the immune system has a loose anatomical structure, in which molecular and cellular events mostly occur at random; 2) The immune system can respond to molecules of the living world whereas the nervous system can respond to phenomena of the physical world; 3) Responses of the immune system act both on the organism and on the stimulus that triggered the response, whereas responses of the nervous system act on the organism only. The nervous and the immune systems therefore appear as two complementary systems of relations that closely work together, and whose reactivities are well-suited to deal with physical and biological stimuli, respectively. Its ability both to adapt the organism to the living world and to adapt the living world to the organism endows the immune system with powerful adaptive properties that enable the organism to live in peace with itself and with other living beings, whether pathogens or commensals.
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Affiliation(s)
- Marc Daëron
- Centre d’Immunologie de Marseille-Luminy, Aix Marseille Université-CNRS-Inserm, Marseille, France
- Institut Pasteur-Université Paris Cité, Paris, France
- Institut d’histoire et de philosophie des sciences et des techniques, Université Paris 1 Panthéon Sorbonne-CNRS, Paris, France
- *Correspondence: Marc Daëron,
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21
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Abstract
Introduction Neutrophilic granulocytes are short‐lived cells continuously circulating in the vascular system of vertebrates. They play a basic and decisive role in the innate immune defence of the hosts against all types of pathogenic microorganisms. Methods Based on a literature study, the functions of neutrophils and cells with similar functions are described. The study places special emphasis on organisms in the aquatic environment and the pathogens occurring in that particular environment. Results The evolutionary origin of this specific cell type is not clear, but its most basic traits (recognition of foreign elements, extracellular trap release, phagocytosis and elimination of ingested material) are found in phagocytes in members of evolutionary ancient invertebrate groups spanning from amoebae, sponges, sea‐anemones, mollusks (snails and mussels), arthropods (crustaceans and insects) to echinoderms (sea stars and sea urchins). Their functions as innate immune sentinels and effector cells in these groups are well described. Neutrophilic granulocytes with elongated and lobed nuclei (possibly allowing cell movements through narrow extracellular spaces and leaving space for phagosomes) occur in vertebrates including fish, amphibians, reptiles, birds and mammals although the morphology of the nucleus, stainability of cytoplasmic granula, and the antimicrobial armament vary among groups. Following the pathogen invasion of a fish host, the neutrophils migrates from the vascular system into the infection focus. They apply their PRRs (including TLRs) to recognize the invader as non‐self, produce netosis by casting extracellular chromatin containing traps in the microenvironment. These nets assist the immobilization of invading microbes and prevents their further spread. The cells attach to and engulf the microbes by phagocytosis, whereafter they eliminate the pathogen in phagolysosomes equipped with a range of killing mechanisms and attract, by release of chemokines, additional immune cells (monocytes, macrophages and lymphocytes) to the site of invasion. Their role in innate immunity of fish hosts towards aquatic pathogens has been elucidated by in vivo and in vitro studies. Neutrophils interact with virus (e.g. IPNV and VHSV), bacteria (e.g. Aeromonas, Vibrio, Edwardsiella, Mycobacterium and Renibacterium) and parasites, including monogeneans (Gyrodactylus), cestodes (Diphyllobothrium), trematodes (Diplostomum) and ciliates (Ichthyophthirius and Philasterides). Despite the decisive function of neutrophils in innate immunity and early protection, the excessive production of ROS, RNS and NETs may lead to pathological disturbances in the host, which are exacerbated if the pathogens evolve immune evasion mechanisms. Conclusion Neutrophils in aquatic organisms play a central role in innate immunity but may serve as a toll and a support in acquired protection. The strong impact of the cellular reactions not only on pathogen but also on host tissues emphasizes that an optimal immune reaction is balanced, involves targeted and specific effector mechanisms, which leaves a minimum of collateral damage in host organs.
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Affiliation(s)
- Kurt Buchmann
- Laboratory of Aquatic Pathobiology, Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark
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22
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D'Amico AE, Wong AC, Zajd CM, Zhang X, Murali A, Trebak M, Lennartz MR. PKC-ε regulates vesicle delivery and focal exocytosis for efficient IgG-mediated phagocytosis. J Cell Sci 2021; 134:jcs258886. [PMID: 34622926 PMCID: PMC8627556 DOI: 10.1242/jcs.258886] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Accepted: 09/27/2021] [Indexed: 11/20/2022] Open
Abstract
Protein kinase C (PKC)-ε is required for membrane addition during IgG-mediated phagocytosis, but its role in this process is ill defined. Here, we performed high-resolution imaging, which reveals that PKC-ε exits the Golgi and enters phagosomes on vesicles that then fuse. TNF and PKC-ε colocalize at the Golgi and on vesicles that enter the phagosome. Loss of PKC-ε and TNF delivery upon nocodazole treatment confirmed vesicular transport on microtubules. That TNF+ vesicles were not delivered in macrophages from PKC-ε null mice, or upon dissociation of the Golgi-associated pool of PKC-ε, implies that Golgi-tethered PKC-ε is a driver of Golgi-to-phagosome trafficking. Finally, we established that the regulatory domain of PKC-ε is sufficient for delivery of TNF+ vesicles to the phagosome. These studies reveal a novel role for PKC-ε in focal exocytosis - its regulatory domain drives Golgi-derived vesicles to the phagosome, whereas catalytic activity is required for their fusion. This is one of the first examples of a PKC requirement for vesicular trafficking and describes a novel function for a PKC regulatory domain. This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Anna E. D'Amico
- Albany Medical College, 47 New Scotland Ave MC-165, Albany, NY 12208, USA
| | - Alexander C. Wong
- Albany Medical College, 47 New Scotland Ave MC-165, Albany, NY 12208, USA
| | - Cheryl M. Zajd
- Albany Medical College, 47 New Scotland Ave MC-165, Albany, NY 12208, USA
| | - Xuexin Zhang
- Penn State College of Medicine, 500 University Dr., Hershey, PA 17033, USA
| | - Ananya Murali
- Albany Medical College, 47 New Scotland Ave MC-165, Albany, NY 12208, USA
| | - Mohamed Trebak
- University of Pittsburgh School of Medicine, 2550 Terrace Street, Pittsburgh, PA 15231, USA
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23
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Pears CJ, Brustel J, Lakin ND. Dictyostelium discoideum as a Model to Assess Genome Stability Through DNA Repair. Front Cell Dev Biol 2021; 9:752175. [PMID: 34692705 PMCID: PMC8529158 DOI: 10.3389/fcell.2021.752175] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Accepted: 09/20/2021] [Indexed: 11/25/2022] Open
Abstract
Preserving genome integrity through repair of DNA damage is critical for human health and defects in these pathways lead to a variety of pathologies, most notably cancer. The social amoeba Dictyostelium discoideum is remarkably resistant to DNA damaging agents and genome analysis reveals it contains orthologs of several DNA repair pathway components otherwise limited to vertebrates. These include the Fanconi Anemia DNA inter-strand crosslink and DNA strand break repair pathways. Loss of function of these not only results in malignancy, but also neurodegeneration, immune-deficiencies and congenital abnormalities. Additionally, D. discoideum displays remarkable conservations of DNA repair factors that are targets in cancer and other therapies, including poly(ADP-ribose) polymerases that are targeted to treat breast and ovarian cancers. This, taken together with the genetic tractability of D. discoideum, make it an attractive model to assess the mechanistic basis of DNA repair to provide novel insights into how these pathways can be targeted to treat a variety of pathologies. Here we describe progress in understanding the mechanisms of DNA repair in D. discoideum, and how these impact on genome stability with implications for understanding development of malignancy.
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Affiliation(s)
- Catherine J. Pears
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom
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24
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Haselkorn TS, Jimenez D, Bashir U, Sallinger E, Queller DC, Strassmann JE, DiSalvo S. Novel Chlamydiae and Amoebophilus endosymbionts are prevalent in wild isolates of the model social amoeba Dictyostelium discoideum. ENVIRONMENTAL MICROBIOLOGY REPORTS 2021; 13:708-719. [PMID: 34159734 PMCID: PMC8518690 DOI: 10.1111/1758-2229.12985] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2020] [Accepted: 06/12/2021] [Indexed: 05/24/2023]
Abstract
Amoebae interact with bacteria in multifaceted ways. Amoeba predation can serve as a selective pressure for the development of bacterial virulence traits. Bacteria may also adapt to life inside amoebae, resulting in symbiotic relationships. Indeed, particular lineages of obligate bacterial endosymbionts have been found in different amoebae. Here, we screened an extensive collection of Dictyostelium discoideum wild isolates for the presence of these bacterial symbionts using endosymbiont specific PCR primers. We find that these symbionts are surprisingly common, identified in 42% of screened isolates (N = 730). Members of the Chlamydiae phylum are particularly prevalent, occurring in 27% of the amoeba isolated. They are novel and phylogenetically distinct from other Chlamydiae. We also found Amoebophilus symbionts in 8% of screened isolates (N = 730). Antibiotic-cured amoebae behave similarly to their Chlamydiae or Amoebophilus-infected counterparts, suggesting that these endosymbionts do not significantly impact host fitness, at least in the laboratory. We found several natural isolates were co-infected with multiple endosymbionts, with no obvious fitness effect of co-infection under laboratory conditions. The high prevalence and novelty of amoeba endosymbiont clades in the model organism D. discoideum opens the door to future research on the significance and mechanisms of amoeba-symbiont interactions.
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Affiliation(s)
- Tamara S. Haselkorn
- Department of BiologyUniversity of Central Arkansas201 Donaghey Avenue, ConwayAR72035USA
| | - Daniela Jimenez
- Department of BiologyWashington University in St. LouisOne Brookings Drive St. LouisMO63130USA
| | - Usman Bashir
- Department of BiologyWashington University in St. LouisOne Brookings Drive St. LouisMO63130USA
| | - Eleni Sallinger
- Department of BiologyUniversity of Central Arkansas201 Donaghey Avenue, ConwayAR72035USA
| | - David C. Queller
- Department of BiologyWashington University in St. LouisOne Brookings Drive St. LouisMO63130USA
| | - Joan E. Strassmann
- Department of BiologyWashington University in St. LouisOne Brookings Drive St. LouisMO63130USA
| | - Susanne DiSalvo
- Department of Biological SciencesSouthern Illinois University Edwardsville44 Circle Drive, EdwardsvilleIL62026USA
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25
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Xu X, Pan M, Jin T. How Phagocytes Acquired the Capability of Hunting and Removing Pathogens From a Human Body: Lessons Learned From Chemotaxis and Phagocytosis of Dictyostelium discoideum (Review). Front Cell Dev Biol 2021; 9:724940. [PMID: 34490271 PMCID: PMC8417749 DOI: 10.3389/fcell.2021.724940] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Accepted: 07/15/2021] [Indexed: 12/01/2022] Open
Abstract
How phagocytes find invading microorganisms and eliminate pathogenic ones from human bodies is a fundamental question in the study of infectious diseases. About 2.5 billion years ago, eukaryotic unicellular organisms-protozoans-appeared and started to interact with various bacteria. Less than 1 billion years ago, multicellular animals-metazoans-appeared and acquired the ability to distinguish self from non-self and to remove harmful organisms from their bodies. Since then, animals have developed innate immunity in which specialized white-blood cells phagocytes- patrol the body to kill pathogenic bacteria. The social amoebae Dictyostelium discoideum are prototypical phagocytes that chase various bacteria via chemotaxis and consume them as food via phagocytosis. Studies of this genetically amendable organism have revealed evolutionarily conserved mechanisms underlying chemotaxis and phagocytosis and shed light on studies of phagocytes in mammals. In this review, we briefly summarize important studies that contribute to our current understanding of how phagocytes effectively find and kill pathogens via chemotaxis and phagocytosis.
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Affiliation(s)
| | | | - Tian Jin
- Chemotaxis Signal Section, Laboratory of Immunogenetics, NIAID, NIH, Rockville, MD, United States
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Amoebae as Targets for Toxins or Effectors Secreted by Mammalian Pathogens. Toxins (Basel) 2021; 13:toxins13080526. [PMID: 34437397 PMCID: PMC8402458 DOI: 10.3390/toxins13080526] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Revised: 07/26/2021] [Accepted: 07/26/2021] [Indexed: 11/28/2022] Open
Abstract
Numerous microorganisms, pathogenic for mammals, come from the environment where they encounter predators such as free-living amoebae (FLA). The selective pressure due to this interaction could have generated virulence traits that are deleterious for amoebae and represents a weapon against mammals. Toxins are one of these powerful tools that are essential for bacteria or fungi to survive. Which amoebae are used as a model to study the effects of toxins? What amoeba functions have been reported to be disrupted by toxins and bacterial secreted factors? Do bacteria and fungi effectors affect eukaryotic cells similarly? Here, we review some studies allowing to answer these questions, highlighting the necessity to extend investigations of microbial pathogenicity, from mammals to the environmental reservoir that are amoebae.
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Host-pathogen interactions: lessons from phagocytic predation on fungi. Curr Opin Microbiol 2021; 62:38-44. [PMID: 34051610 DOI: 10.1016/j.mib.2021.04.010] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2021] [Revised: 04/21/2021] [Accepted: 04/30/2021] [Indexed: 12/24/2022]
Abstract
Free living amoebae share striking similarities with innate immune cells in terms of cell morphology, motility and phagocytic processing of microbes. Their abilities to find, ingest and kill bacteria and fungi in their natural habitats have fostered the hypothesis that amoebae could have served as a training ground for environmentally acquired pathogens. What may have been more obvious for intracellular bacteria, becomes increasingly clear also for several fungal pathogens: a number of virulence determinants of human pathogenic fungi such as Cryptococcus neoformans or Aspergillus fumigatus are equally relevant to resist innate immune cells and environmental phagocytic predators. Here, we summarize the most recent experimental examples underlining the concept of amoeba models to study fungal pathogens.
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Abstract
Tissue-resident macrophages are present in most tissues with developmental, self-renewal, or functional attributes that do not easily fit into a textbook picture of a plastic and multifunctional macrophage originating from hematopoietic stem cells; nor does it fit a pro- versus anti-inflammatory paradigm. This review presents and discusses current knowledge on the developmental biology of macrophages from an evolutionary perspective focused on the function of macrophages, which may aid in study of developmental, inflammatory, tumoral, and degenerative diseases. We also propose a framework to investigate the functions of macrophages in vivo and discuss how inherited germline and somatic mutations may contribute to the roles of macrophages in diseases.
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Affiliation(s)
- Nehemiah Cox
- Immunology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA;
| | - Maria Pokrovskii
- Immunology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA;
| | - Rocio Vicario
- Immunology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA;
| | - Frederic Geissmann
- Immunology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA;
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Pears CJ, Gross JD. Microbe Profile: Dictyostelium discoideum: model system for development, chemotaxis and biomedical research. MICROBIOLOGY-SGM 2021; 167. [PMID: 33646931 DOI: 10.1099/mic.0.001040] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The social amoeba Dictyostelium discoideum is a versatile organism that is unusual in alternating between single-celled and multi-celled forms. It possesses highly-developed systems for cell motility and chemotaxis, phagocytosis, and developmental pattern formation. As a soil amoeba growing on microorganisms, it is exposed to many potential pathogens; it thus provides fruitful ways of investigating host-pathogen interactions and is emerging as an influential model for biomedical research.
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Affiliation(s)
- Catherine J Pears
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
| | - Julian D Gross
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
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Ramos-Martínez E, Hernández-González L, Ramos-Martínez I, Pérez-Campos Mayoral L, López-Cortés GI, Pérez-Campos E, Mayoral Andrade G, Hernández-Huerta MT, José MV. Multiple Origins of Extracellular DNA Traps. Front Immunol 2021; 12:621311. [PMID: 33717121 PMCID: PMC7943724 DOI: 10.3389/fimmu.2021.621311] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Accepted: 01/06/2021] [Indexed: 01/21/2023] Open
Abstract
Extracellular DNA traps (ETs) are evolutionarily conserved antimicrobial mechanisms present in protozoa, plants, and animals. In this review, we compare their similarities in species of different taxa, and put forward the hypothesis that ETs have multiple origins. Our results are consistent with a process of evolutionary convergence in multicellular organisms through the application of a congruency test. Furthermore, we discuss why multicellularity is related to the presence of a mechanism initiating the formation of ETs.
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Affiliation(s)
- Edgar Ramos-Martínez
- School of Sciences, Benito Juárez Autonomous University of Oaxaca, Oaxaca, Mexico
| | | | - Iván Ramos-Martínez
- Glycobiology, Cell Growth and Tissue Repair Research Unit (Gly-CRRET), Université Paris Est Créteil (UPEC), Créteil, France
| | - Laura Pérez-Campos Mayoral
- Research Centre Medicine UNAM-UABJO, Faculty of Medicine, Benito Juárez Autonomous University of Oaxaca, Oaxaca, Mexico
| | | | - Eduardo Pérez-Campos
- Biochemistry and Immunology Unit, National Technological of Mexico/ITOaxaca, Oaxaca, Mexico
- Research Centre Medicine UNAM-UABJO, Faculty of Medicine, Benito Juárez Autonomous University of Oaxaca, Oaxaca, Mexico
| | - Gabriel Mayoral Andrade
- Research Centre Medicine UNAM-UABJO, Faculty of Medicine, Benito Juárez Autonomous University of Oaxaca, Oaxaca, Mexico
| | | | - Marco V. José
- Theoretical Biology Group, National Autonomous University of Mexico, Mexico City, Mexico
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Abstract
Amoebae are protists that have complicated relationships with bacteria, covering the whole spectrum of symbiosis. Amoeba-bacterium interactions contribute to the study of predation, symbiosis, pathogenesis, and human health. Given the complexity of their relationships, it is necessary to understand the ecology and evolution of their interactions. In this paper, we provide an updated review of the current understanding of amoeba-bacterium interactions. We start by discussing the diversity of amoebae and their bacterial partners. We also define three types of ecological interactions between amoebae and bacteria and discuss their different outcomes. Finally, we focus on the implications of amoeba-bacterium interactions on human health, horizontal gene transfer, drinking water safety, and the evolution of symbiosis. In conclusion, amoeba-bacterium interactions are excellent model systems to investigate a wide range of scientific questions. Future studies should utilize advanced techniques to address research gaps, such as detecting hidden diversity, lack of amoeba genomes, and the impacts of amoeba predation on the microbiome.
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Sallinger E, Robeson MS, Haselkorn TS. Characterization of the bacterial microbiomes of social amoebae and exploration of the roles of host and environment on microbiome composition. Environ Microbiol 2020; 23:126-142. [PMID: 33063404 DOI: 10.1111/1462-2920.15279] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Revised: 10/11/2020] [Accepted: 10/11/2020] [Indexed: 01/04/2023]
Abstract
As predators of bacteria, amoebae select for traits that allow bacteria to become symbionts by surviving phagocytosis and exploiting the eukaryotic intracellular environment. Soil-dwelling social amoebae can help us answer questions about the natural ecology of these amoeba-bacteria symbioses along the pathogen-mutualist spectrum. Our objective was to characterize the natural bacterial microbiome of phylogenetically and morphologically diverse social amoeba species using next-generation sequencing of 16S rRNA amplicons directly from amoeba fruiting bodies. We found six phyla of amoeba-associated bacteria: Proteobacteria, Bacteroidetes, Actinobacteria, Chlamydiae, Firmicutes, and Acidobacteria. The most common associates of amoebae were classified to order Chlamydiales and genus Burkholderia-Caballeronia-Paraburkholderia. These bacteria were present in multiple amoeba species across multiple locations. While there was substantial intraspecific variation, there was some evidence for host specificity and differentially abundant taxa between different amoeba hosts. Amoebae microbiomes were distinct from the microbiomes of their soil habitat, and soil pH affected amoeba microbiome diversity. Alpha-diversity was unsurprisingly lower in amoebae samples compared with soil, but beta-diversity between amoebae samples was higher than between soil samples. Further exploration of social amoebae microbiomes may help us understand the roles of bacteria, host, and environment on symbiotic interactions and microbiome formation in basal eukaryotic organisms.
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Affiliation(s)
- Eleni Sallinger
- Department of Biology, University of Central Arkansas, Conway, AR, 72035, USA
| | - Michael S Robeson
- Department of Biomedical Informatics, University of Arkansas for Medical Sciences, Little Rock, AR, 72205, USA
| | - Tamara S Haselkorn
- Department of Biology, University of Central Arkansas, Conway, AR, 72035, USA
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33
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Pull CD, McMahon DP. Superorganism Immunity: A Major Transition in Immune System Evolution. Front Ecol Evol 2020. [DOI: 10.3389/fevo.2020.00186] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
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Paraburkholderia Symbionts Display Variable Infection Patterns That Are Not Predictive of Amoeba Host Outcomes. Genes (Basel) 2020; 11:genes11060674. [PMID: 32575747 PMCID: PMC7349545 DOI: 10.3390/genes11060674] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Revised: 06/07/2020] [Accepted: 06/18/2020] [Indexed: 12/17/2022] Open
Abstract
Symbiotic interactions exist within a parasitism to mutualism continuum that is influenced, among others, by genes and context. Dynamics of intracellular invasion, replication, and prevalence may underscore both host survivability and symbiont stability. More infectious symbionts might exert higher corresponding costs to hosts, which could ultimately disadvantage both partners. Here, we quantify infection patterns of diverse Paraburkholderia symbiont genotypes in their amoeba host Dictyostelium discoideum and probe the relationship between these patterns and host outcomes. We exposed D. discoideum to thirteen strains of Paraburkholderia each belonging to one of the three symbiont species found to naturally infect D. discoideum: Paraburkholderia agricolaris, Paraburkholderia hayleyella, and Paraburkholderia bonniea. We quantified the infection prevalence and intracellular density of fluorescently labeled symbionts along with the final host population size using flow cytometry and confocal microscopy. We find that infection phenotypes vary across symbiont strains. Symbionts belonging to the same species generally display similar infection patterns but are interestingly distinct when it comes to host outcomes. This results in final infection loads that do not strongly correlate to final host outcomes, suggesting other genetic factors that are not a direct cause or consequence of symbiont abundance impact host fitness.
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35
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O'Day DH, Mathavarajah S, Myre MA, Huber RJ. Calmodulin-mediated events during the life cycle of the amoebozoan Dictyostelium discoideum. Biol Rev Camb Philos Soc 2020; 95:472-490. [PMID: 31774219 PMCID: PMC7079120 DOI: 10.1111/brv.12573] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2019] [Revised: 10/30/2019] [Accepted: 11/11/2019] [Indexed: 12/14/2022]
Abstract
This review focusses on the functions of intracellular and extracellular calmodulin, its target proteins and their binding proteins during the asexual life cycle of Dictyostelium discoideum. Calmodulin is a primary regulatory protein of calcium signal transduction that functions throughout all stages. During growth, it mediates autophagy, the cell cycle, folic acid chemotaxis, phagocytosis, and other functions. During mitosis, specific calmodulin-binding proteins translocate to alternative locations. Translocation of at least one cell adhesion protein is calmodulin dependent. When starved, cells undergo calmodulin-dependent chemotaxis to cyclic AMP generating a multicellular pseudoplasmodium. Calmodulin-dependent signalling within the slug sets up a defined pattern and polarity that sets the stage for the final events of morphogenesis and cell differentiation. Transected slugs undergo calmodulin-dependent transdifferentiation to re-establish the disrupted pattern and polarity. Calmodulin function is critical for stalk cell differentiation but also functions in spore formation, events that begin in the pseudoplasmodium. The asexual life cycle restarts with the calmodulin-dependent germination of spores. Specific calmodulin-binding proteins as well as some of their binding partners have been linked to each of these events. The functions of extracellular calmodulin during growth and development are also discussed. This overview brings to the forefront the central role of calmodulin, working through its numerous binding proteins, as a primary downstream regulator of the critical calcium signalling pathways that have been well established in this model eukaryote. This is the first time the function of calmodulin and its target proteins have been documented through the complete life cycle of any eukaryote.
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Affiliation(s)
- Danton H. O'Day
- Cell and Systems BiologyUniversity of TorontoTorontoOntarioM5S 3G5Canada
- Department of BiologyUniversity of Toronto MississaugaMississaugaOntarioL5L 1C6Canada
| | | | - Michael A. Myre
- Department of Biological Sciences, Kennedy College of SciencesUniversity of Massachusetts LowellLowellMassachusetts01854USA
| | - Robert J. Huber
- Department of BiologyTrent UniversityPeterboroughOntarioK9L 0G2Canada
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36
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Lamrabet O, Melotti A, Burdet F, Hanna N, Perrin J, Nitschke J, Pagni M, Hilbi H, Soldati T, Cosson P. Transcriptional Responses of Dictyostelium discoideum Exposed to Different Classes of Bacteria. Front Microbiol 2020; 11:410. [PMID: 32210949 PMCID: PMC7078664 DOI: 10.3389/fmicb.2020.00410] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2019] [Accepted: 02/27/2020] [Indexed: 12/19/2022] Open
Abstract
Dictyostelium discoideum amoebae feed by ingesting bacteria, then killing them in phagosomes. Ingestion and killing of different bacteria have been shown to rely on largely different molecular mechanisms. One would thus expect that D. discoideum adapts its ingestion and killing machinery when encountering different bacteria. In this study, we investigated by RNA sequencing if and how D. discoideum amoebae respond to the presence of different bacteria by modifying their gene expression patterns. Each bacterial species analyzed induced a specific modification of the transcriptome. Bacteria such as Bacillus subtilis, Klebsiella pneumoniae, or Mycobacterium marinum induced a specific and different transcriptional response, while Micrococcus luteus did not trigger a significant gene regulation. Although folate has been proposed to be one of the key molecules secreted by bacteria and recognized by hunting amoebae, it elicited a very specific and restricted transcriptional signature, distinct from that triggered by any bacteria analyzed here. Our results indicate that D. discoideum amoebae respond in a highly specific, almost non-overlapping manner to different species of bacteria. We additionally identify specific sets of genes that can be used as reporters of the response of D. discoideum to different bacteria.
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Affiliation(s)
- Otmane Lamrabet
- Department of Cell Physiology and Metabolism, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Astrid Melotti
- Department of Cell Physiology and Metabolism, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Frédéric Burdet
- Vital-IT Group, SIB, Swiss Institute of Bioinformatics, Lausanne, Switzerland
| | - Nabil Hanna
- Department of Biochemistry, Faculty of Science, University of Geneva, Geneva, Switzerland
| | - Jackie Perrin
- Department of Cell Physiology and Metabolism, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Jahn Nitschke
- Department of Biochemistry, Faculty of Science, University of Geneva, Geneva, Switzerland
| | - Marco Pagni
- Vital-IT Group, SIB, Swiss Institute of Bioinformatics, Lausanne, Switzerland
| | - Hubert Hilbi
- Faculty of Medicine, Institute of Medical Microbiology, University of Zurich, Zurich, Switzerland
| | - Thierry Soldati
- Department of Biochemistry, Faculty of Science, University of Geneva, Geneva, Switzerland
| | - Pierre Cosson
- Department of Cell Physiology and Metabolism, Faculty of Medicine, University of Geneva, Geneva, Switzerland
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37
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Butler RE, Smith AA, Mendum TA, Chandran A, Wu H, Lefrançois L, Chambers M, Soldati T, Stewart GR. Mycobacterium bovis uses the ESX-1 Type VII secretion system to escape predation by the soil-dwelling amoeba Dictyostelium discoideum. ISME JOURNAL 2020; 14:919-930. [PMID: 31896783 PMCID: PMC7082363 DOI: 10.1038/s41396-019-0572-z] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Revised: 11/26/2019] [Accepted: 12/11/2019] [Indexed: 12/11/2022]
Abstract
Mycobacterium bovis is the causative agent of bovine tuberculosis and the predominant cause of zoonotic tuberculosis in people. Bovine tuberculosis occurs in farmed cattle but also in a variety of wild animals, which form a reservoir of infection. Although direct transmission of tuberculosis occurs between mammals, the low frequency of contact between different host species and abundant shedding of bacilli by infected animals suggests an infectious route via environmental contamination. Other intracellular pathogens that transmit via the environment deploy strategies to survive or exploit predation by environmental amoebae. To explore if M. bovis has this capability, we investigated its interactions with the soil and dung-dwelling amoeba, Dictyostelium discoideum. We demonstrated that M. bovis evades phagocytosis and destruction by D. discoideum and actively transits through the amoeba using the ESX-1 Type VII Secretion System as part of a programme of mechanisms, many of which have been co-opted as virulence factors in the mammalian host. This capacity of M. bovis to utilise an environmental stage between mammalian hosts may enhance its transmissibility. In addition, our data provide molecular evidence to support an evolutionary role for amoebae as training grounds for the pathogenic M. tuberculosis complex.
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Affiliation(s)
- Rachel E Butler
- Department of Microbial Sciences, School of Biosciences and Medicine, University of Surrey, Guildford, Surrey, GU2 7XH, UK
| | - Alex A Smith
- Department of Microbial Sciences, School of Biosciences and Medicine, University of Surrey, Guildford, Surrey, GU2 7XH, UK
| | - Tom A Mendum
- Department of Microbial Sciences, School of Biosciences and Medicine, University of Surrey, Guildford, Surrey, GU2 7XH, UK
| | - Aneesh Chandran
- Department of Microbial Sciences, School of Biosciences and Medicine, University of Surrey, Guildford, Surrey, GU2 7XH, UK
| | - Huihai Wu
- Department of Microbial Sciences, School of Biosciences and Medicine, University of Surrey, Guildford, Surrey, GU2 7XH, UK
| | - Louise Lefrançois
- Department of Biochemistry, Science II, University of Geneva, 30 quai Ernest-Ansermet, Geneva, Switzerland
| | - Mark Chambers
- School of Veterinary Medicine, University of Surrey, Guildford, Surrey, GU2 7AL, UK
| | - Thierry Soldati
- Department of Biochemistry, Science II, University of Geneva, 30 quai Ernest-Ansermet, Geneva, Switzerland
| | - Graham R Stewart
- Department of Microbial Sciences, School of Biosciences and Medicine, University of Surrey, Guildford, Surrey, GU2 7XH, UK.
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38
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Kloc M, Uosef A, Elshawwaf M, Abdelshafy AAA, Elsaid KMK, Kubiak JZ, Ghobrial RM. The Macrophages and Intestinal Symbiosis. Results Probl Cell Differ 2020; 69:605-616. [PMID: 33263889 DOI: 10.1007/978-3-030-51849-3_23] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The human intestinal tract is inhabited by trillions of microorganisms and houses the largest pool of macrophages in the human body. Being a part of the innate immune system, the macrophages, the professional phagocytes, vigorously respond to the microbial and dietary antigens present in the intestine. Because such a robust immune response poses the danger to the survival of the non-harmful and beneficial gut microbiota, the macrophages developed mechanisms of recognition and hyposensitivity toward the non-harmful/beneficial inhabitants of the gut. We will discuss the evolution and identity of some of these mechanisms in the following chapter.
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Affiliation(s)
- Malgorzata Kloc
- The Houston Methodist Research Institute, Houston, TX, USA. .,Department of Surgery, Houston Methodist Hospital, Houston, TX, USA. .,Department of Genetics, The University of Texas, M.D. Anderson Cancer Center, Houston, TX, USA.
| | - Ahmed Uosef
- The Houston Methodist Research Institute, Houston, TX, USA.,Department of Surgery, Houston Methodist Hospital, Houston, TX, USA
| | - Mahmoud Elshawwaf
- The Houston Methodist Research Institute, Houston, TX, USA.,Department of Surgery, Houston Methodist Hospital, Houston, TX, USA
| | - Ahmed Adel Abbas Abdelshafy
- The Houston Methodist Research Institute, Houston, TX, USA.,Department of Surgery, Houston Methodist Hospital, Houston, TX, USA.,Department of General Surgery, Faculty of Medicine, Ain-Shams University, Cairo, Egypt
| | - Kamal Mamdoh Kamal Elsaid
- The Houston Methodist Research Institute, Houston, TX, USA.,Department of Surgery, Houston Methodist Hospital, Houston, TX, USA.,Department of General Surgery, Faculty of Medicine, Ain-Shams University, Cairo, Egypt
| | - Jacek Z Kubiak
- Department of Regenerative Medicine and Cell Biology, Military Institute of Hygiene and Epidemiology (WIHE), Warszawa, Poland.,Faculty of Medicine, Cell Cycle Group, Institute of Genetics and Development of Rennes, (IGDR) UnivRennes, CNRS, UMR 6290, Rennes, France
| | - Rafik Mark Ghobrial
- The Houston Methodist Research Institute, Houston, TX, USA.,Department of Surgery, Houston Methodist Hospital, Houston, TX, USA
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Saunders CA, Parent CA. Emerging roles for the nucleus during neutrophil signal relay and NETosis. Curr Opin Cell Biol 2019; 62:135-143. [PMID: 31835148 DOI: 10.1016/j.ceb.2019.10.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2019] [Revised: 10/14/2019] [Accepted: 10/29/2019] [Indexed: 01/21/2023]
Abstract
The nucleus houses and protects genomic DNA, which is surrounded by the nuclear envelope. Owing to its size and stiffness, the nucleus is often a barrier to migration through confined spaces. Neutrophils are terminally differentiated, short-lived cells that migrate through tissues in response to injury and infections. The neutrophil nucleus is soft, multilobular, and exhibits altered levels of key nuclear envelope proteins. These alterations result in a multifunctional organelle that serves as a signaling hub during migration and NETosis, a process by which neutrophils release decondensed chromatin decorated with granular enzymes that entrap pathogens. In this review, we present emerging evidence suggesting that a unique, ambiguous cell-cycle state is critical for NETosis and migration. Finally, we discuss how the mechanisms underlying migration and NETosis are evolutionarily conserved.
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Affiliation(s)
| | - Carole A Parent
- Department of Pharmacology; Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, MI, 48109, USA.
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40
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Wu Y, Cooper KM. Elastic modulus of Dictyostelium is affected by mechanotransduction. J Biol Phys 2019; 45:293-305. [PMID: 31363883 PMCID: PMC6706517 DOI: 10.1007/s10867-019-09529-1] [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: 09/24/2018] [Accepted: 07/09/2019] [Indexed: 11/28/2022] Open
Abstract
The stiffness of adherent mammalian cells is regulated by the elasticity of substrates due to mechanotransduction via integrin-based focal adhesions. Dictyostelium discoideum is an ameboid protozoan model organism that does not carry genes for classical integrin and can adhere to substrates without forming focal adhesions. It also has a life cycle that naturally includes both single-cellular and multicellular life forms. In this article, we report the measurements of the elastic modulus of single cells on varied substrate stiffnesses and the elastic modulus of the multicellular "slug" using atomic force microscopy (AFM) as a microindenter/force transducer. The results show that the elastic modulus of the Dictyostelium cell is regulated by the stiffness of the substrate and its surrounding cells, which is similar to the mechanotransduction behavior of mammalian cells.
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Affiliation(s)
- Yan Wu
- Department of Engineering Physics, University of Wisconsin-Platteville, 1 University Plaza, Platteville, WI, 53818, USA
| | - Kate M Cooper
- Department of Biology, Loras College, 1450 Alta Vista Street, Dubuque, IA, 52001, USA.
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41
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Gaertner F, Massberg S. Patrolling the vascular borders: platelets in immunity to infection and cancer. Nat Rev Immunol 2019; 19:747-760. [DOI: 10.1038/s41577-019-0202-z] [Citation(s) in RCA: 117] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/11/2019] [Indexed: 12/13/2022]
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42
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Khojandi N, Haselkorn TS, Eschbach MN, Naser RA, DiSalvo S. Intracellular Burkholderia Symbionts induce extracellular secondary infections; driving diverse host outcomes that vary by genotype and environment. THE ISME JOURNAL 2019; 13:2068-2081. [PMID: 31019270 PMCID: PMC6776111 DOI: 10.1038/s41396-019-0419-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Revised: 01/06/2019] [Accepted: 04/10/2019] [Indexed: 02/07/2023]
Abstract
Symbiotic associations impact and are impacted by their surrounding ecosystem. The association between Burkholderia bacteria and the soil amoeba Dictyostelium discoideum is a tractable model to unravel the biology underlying symbiont-endowed phenotypes and their impacts. Several Burkholderia species stably associate with D. discoideum and typically reduce host fitness in food-rich environments while increasing fitness in food-scarce environments. Burkholderia symbionts are themselves inedible to their hosts but induce co-infections with secondary bacteria that can serve as a food source. Thus, Burkholderia hosts are "farmers" that carry food bacteria to new environments, providing a benefit when food is scarce. We examined the ability of specific Burkholderia genotypes to induce secondary co-infections and assessed host fitness under a range of co-infection conditions and environmental contexts. Although all Burkholderia symbionts intracellularly infected Dictyostelium, we found that co-infections are predominantly extracellular, suggesting that farming benefits are derived from extracellular infection of host structures. Furthermore, levels of secondary infection are linked to conditional host fitness; B. agricolaris infected hosts have the highest level of co-infection and have the highest fitness in food-scarce environments. This study illuminates the phenomenon of co-infection induction across Dictyostelium associated Burkholderia species and exemplifies the contextual complexity of these associations.
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Affiliation(s)
- Niloufar Khojandi
- Department of Biological Sciences, Southern Illinois University Edwardsville, Edwardsville, IL, 62026, USA
- Department of Molecular Microbiology and Immunology, St. Louis University, St. Louis, MO, 63104, USA
| | - Tamara S Haselkorn
- Department of Biology, University of Central Arkansas, 201 Donaghey Avenue, Conway, AR, 72035, USA
| | - Madison N Eschbach
- Department of Biological Sciences, Southern Illinois University Edwardsville, Edwardsville, IL, 62026, USA
| | - Rana A Naser
- Department of Biological Sciences, Southern Illinois University Edwardsville, Edwardsville, IL, 62026, USA
| | - Susanne DiSalvo
- Department of Biological Sciences, Southern Illinois University Edwardsville, Edwardsville, IL, 62026, USA.
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Soldati T, Cardenal-Muñoz E. A brief historical and evolutionary perspective on the origin of cellular microbiology research. Cell Microbiol 2019; 21:e13083. [PMID: 31290267 DOI: 10.1111/cmi.13083] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2019] [Revised: 07/02/2019] [Accepted: 07/08/2019] [Indexed: 12/01/2022]
Abstract
Integrated with both a historical perspective and an evolutionary angle, this opinion article presents a brief and personal view of the emergence of cellular microbiology research. From the very first observations of phagocytosis by Goeze in 1777 to the exhaustive analysis of the cellular defence mechanisms performed in modern laboratories, the studies by cell biologists and microbiologists have converged into an integrative research field distinct from, but fully coupled to immunity: cellular microbiology. In addition, this brief article is thought as a humble patchwork of the motivations that have guided the research in my group over a quarter century.
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Affiliation(s)
- Thierry Soldati
- Faculty of Science, Sciences II, Department of Biochemistry, University of Geneva, Geneva, Switzerland
| | - Elena Cardenal-Muñoz
- Faculty of Science, Sciences II, Department of Biochemistry, University of Geneva, Geneva, Switzerland
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Farinholt T, Dinh C, Kuspa A. Social amoebae establish a protective interface with their bacterial associates by lectin agglutination. SCIENCE ADVANCES 2019; 5:eaav4367. [PMID: 31355329 PMCID: PMC6656538 DOI: 10.1126/sciadv.aav4367] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2018] [Accepted: 06/20/2019] [Indexed: 05/13/2023]
Abstract
Both animals and amoebae use phagocytosis and DNA-based extracellular traps as anti-bacterial defense mechanisms. Whether, like animals, amoebae also use tissue-level barriers to reduce direct contact with bacteria has remained unclear. We have explored this question in the social amoeba Dictyostelium discoideum, which forms plaques on lawns of bacteria that expand as amoebae divide and bacteria are consumed. We show that CadA, a cell adhesion protein that functions in D. discoideum development, is also a bacterial agglutinin that forms a protective interface at the plaque edge that limits exposure of vegetative amoebae to bacteria. This interface is important for amoebal survival when bacteria-to-amoebae ratios are high, optimizing amoebal feeding behavior, and protecting amoebae from oxidative stress. Lectins also control bacterial access to the gut epithelium of mammals to limit inflammatory processes; thus, this strategy of antibacterial defense is shared across a broad spectrum of eukaryotic taxa.
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Affiliation(s)
- Timothy Farinholt
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Christopher Dinh
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX 77030, USA
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Adam Kuspa
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX 77030, USA
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
- Corresponding author.
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Miermont A, Antolović V, Lenn T, Nichols JME, Millward LJ, Chubb JR. The fate of cells undergoing spontaneous DNA damage during development. Development 2019; 146:dev174268. [PMID: 30975700 PMCID: PMC6602350 DOI: 10.1242/dev.174268] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2018] [Accepted: 04/03/2019] [Indexed: 12/20/2022]
Abstract
Embryonic development involves extensive and often rapid cell proliferation. An unavoidable side effect of cell proliferation is DNA damage. The consequences of spontaneous DNA damage during development are not clear. Here, we define an approach to determine the effects of DNA damage on cell fate choice. Using single cell transcriptomics, we identified a subpopulation of Dictyostelium cells experiencing spontaneous DNA damage. Damaged cells displayed high expression of rad51, with the gene induced by multiple types of genotoxic stress. Using live imaging, we tracked high Rad51 cells from differentiation onset until cell fate assignment. High Rad51 cells were shed from multicellular structures, excluding damaged cells from the spore population. Cell shedding resulted from impaired cell motility and defective cell-cell adhesion, with damaged cells additionally defective in activation of spore gene expression. These data indicate DNA damage is not insulated from other aspects of cell physiology during development and multiple features of damaged cells prevent propagation of genetic error. Our approach is generally applicable for monitoring rare subpopulations during development, and permits analysis of developmental perturbations occurring within a physiological dynamic range.
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Affiliation(s)
- Agnes Miermont
- MRC Laboratory for Molecular Cell Biology and Department of Cell and Developmental Biology, University College London, Gower Street, London WC1E 6BT, London, UK
| | - Vlatka Antolović
- MRC Laboratory for Molecular Cell Biology and Department of Cell and Developmental Biology, University College London, Gower Street, London WC1E 6BT, London, UK
| | - Tchern Lenn
- MRC Laboratory for Molecular Cell Biology and Department of Cell and Developmental Biology, University College London, Gower Street, London WC1E 6BT, London, UK
| | - John M E Nichols
- MRC Laboratory for Molecular Cell Biology and Department of Cell and Developmental Biology, University College London, Gower Street, London WC1E 6BT, London, UK
| | - Lindsey J Millward
- MRC Laboratory for Molecular Cell Biology and Department of Cell and Developmental Biology, University College London, Gower Street, London WC1E 6BT, London, UK
| | - Jonathan R Chubb
- MRC Laboratory for Molecular Cell Biology and Department of Cell and Developmental Biology, University College London, Gower Street, London WC1E 6BT, London, UK
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Antolović V, Lenn T, Miermont A, Chubb JR. Transition state dynamics during a stochastic fate choice. Development 2019; 146:dev173740. [PMID: 30890571 PMCID: PMC6602359 DOI: 10.1242/dev.173740] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Accepted: 03/07/2019] [Indexed: 12/31/2022]
Abstract
The generation of multiple fates from a uniform cell population via self-organisation is a recurring feature in development and regeneration. However, for most self-organising systems, we have little understanding of the processes that allow cells to become different. One of the clearest examples of developmental self-organisation is shown by Dictyostelium, with cells segregating into two major fates, stalk and spore, within multicellular aggregates. To characterise the gene expression decisions that underlie this cell fate bifurcation, we carried out single cell transcriptomics on Dictyostelium aggregates. Our data show the transition of progenitors into prespore and prestalk cells occurs via distinct developmental intermediates. Few cells were captured switching between states, with minimal overlap in fate marker expression between cell types, suggesting states are discrete and transitions rapid. Surprisingly, fate-specific transcript dynamics were a small proportion of overall gene expression changes, with transcript divergence coinciding precisely with large-scale remodelling of the transcriptome shared by prestalk and prespore cells. These observations suggest the stepwise separation of cell identity is temporally coupled to global expression transitions common to both fates.
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Affiliation(s)
- Vlatka Antolović
- Laboratory for Molecular Cell Biology and Division of Cell and Developmental Biology, University College London, Gower Street, London WC1E 6BT, UK
| | - Tchern Lenn
- Laboratory for Molecular Cell Biology and Division of Cell and Developmental Biology, University College London, Gower Street, London WC1E 6BT, UK
| | - Agnes Miermont
- Laboratory for Molecular Cell Biology and Division of Cell and Developmental Biology, University College London, Gower Street, London WC1E 6BT, UK
| | - Jonathan R Chubb
- Laboratory for Molecular Cell Biology and Division of Cell and Developmental Biology, University College London, Gower Street, London WC1E 6BT, UK
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47
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The medicinal leech as a valuable model for better understanding the role of a TLR4-like receptor in the inflammatory process. Cell Tissue Res 2019; 377:245-257. [PMID: 30919048 DOI: 10.1007/s00441-019-03010-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Accepted: 02/26/2019] [Indexed: 12/21/2022]
Abstract
Despite extensive investigation focused on both the molecular characteristics and the expression level of Toll-like receptors (TLRs) during the inflammatory response in vertebrates, few data are available in the literature on the role of these proteins in invertebrate's immune response. Here, we propose the medicinal leech as a valuable model to better elucidate the role of TLR4 and its related products, such as tumor necrosis factor (TNF-α), after activation of the leech peripheral immune system with the endogenous medicinal leech recombinant allograft inflammatory factor-1 (rHmAIF-1) or with an exogenous stimulus, such as lipopolysaccharide (LPS). Our results indicate that activated macrophages (HmAIF-1+) and granulocytes (CD11b+) express both TLR4 and its coreceptor CD14. Moreover, functional studies performed by injecting a cyanobacterium selective TLR4 antagonist CyP demonstrated that only the TLR4 pathway was blocked, while the immune response caused by lipoteichoic acid (LTA) treatment is not affected. These results are consistent with literature on vertebrates, indicating that TLR4 functions as a LPS receptor while the recognition of LTA may involve other pathways.
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Rubin M, Miller AD, Katoh-Kurasawa M, Dinh C, Kuspa A, Shaulsky G. Cooperative predation in the social amoebae Dictyostelium discoideum. PLoS One 2019; 14:e0209438. [PMID: 30625171 PMCID: PMC6326426 DOI: 10.1371/journal.pone.0209438] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2018] [Accepted: 12/05/2018] [Indexed: 12/05/2022] Open
Abstract
The eukaryotic amoeba Dictyostelium discoideum is commonly used to study sociality. The amoebae cooperate during development, exhibiting altruism, cheating, and kin-discrimination, but growth while preying on bacteria has been considered asocial. Here we show that Dictyostelium are cooperative predators. Using mutants that grow poorly on Gram-negative bacteria but grow well on Gram-positive bacteria, we show that growth depends on cell-density and on prey type. We also found synergy, by showing that pairwise mixes of different mutants grow well on live Gram-negative bacteria. Moreover, wild-type amoebae produce diffusible factors that facilitate mutant growth and some mutants exploit the wild type in mixed cultures. Finding cooperative predation in D. discoideum should facilitate studies of this fascinating phenomenon, which has not been amenable to genetic analysis before.
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Affiliation(s)
- Michelle Rubin
- Graduate Program in Integrative Molecular and Biomedical Sciences, Baylor College of Medicine, Houston, TX, United States of America
| | - Amber D. Miller
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, United States of America
| | - Mariko Katoh-Kurasawa
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, United States of America
| | - Christopher Dinh
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX, United States of America
| | - Adam Kuspa
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, United States of America
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX, United States of America
| | - Gad Shaulsky
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, United States of America
- * E-mail:
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Shu L, Brock DA, Geist KS, Miller JW, Queller DC, Strassmann JE, DiSalvo S. Symbiont location, host fitness, and possible coadaptation in a symbiosis between social amoebae and bacteria. eLife 2018; 7:e42660. [PMID: 30596477 PMCID: PMC6336404 DOI: 10.7554/elife.42660] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2018] [Accepted: 12/30/2018] [Indexed: 12/14/2022] Open
Abstract
Recent symbioses, particularly facultative ones, are well suited for unravelling the evolutionary give and take between partners. Here we look at variation in natural isolates of the social amoeba Dictyostelium discoideum and their relationships with bacterial symbionts, Burkholderia hayleyella and Burkholderia agricolaris. Only about a third of field-collected amoebae carry a symbiont. We cured and cross-infected amoebae hosts with different symbiont association histories and then compared host responses to each symbiont type. Before curing, field-collected clones did not vary significantly in overall fitness, but infected hosts produced morphologically different multicellular structures. After curing and reinfecting, host fitness declined. However, natural B. hayleyella hosts suffered fewer fitness costs when reinfected with B. hayleyella, indicating that they have evolved mechanisms to tolerate their symbiont. Our work suggests that amoebae hosts have evolved mechanisms to tolerate specific acquired symbionts; exploring host-symbiont relationships that vary within species may provide further insights into disease dynamics.
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Affiliation(s)
- Longfei Shu
- Environmental Microbiomics Research Center and Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, School of Environmental Science and EngineeringSun Yat-sen UniversityGuangzhouChina
- Department of BiologyWashington UniversitySt LouisUnited States
| | - Debra A Brock
- Department of BiologyWashington UniversitySt LouisUnited States
| | | | - Jacob W Miller
- Department of Biological SciencesSouthern Illinois UniversityEdwardsvilleUnited States
| | - David C Queller
- Department of BiologyWashington UniversitySt LouisUnited States
| | | | - Susanne DiSalvo
- Department of Biological SciencesSouthern Illinois UniversityEdwardsvilleUnited States
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50
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Brock DA, Haselkorn TS, Garcia JR, Bashir U, Douglas TE, Galloway J, Brodie F, Queller DC, Strassmann JE. Diversity of Free-Living Environmental Bacteria and Their Interactions With a Bactivorous Amoeba. Front Cell Infect Microbiol 2018; 8:411. [PMID: 30533398 PMCID: PMC6266680 DOI: 10.3389/fcimb.2018.00411] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2018] [Accepted: 11/05/2018] [Indexed: 01/06/2023] Open
Abstract
A small subset of bacteria in soil interact directly with eukaryotes. Which ones do so can reveal what is important to a eukaryote and how eukaryote defenses might be breached. Soil amoebae are simple eukaryotic organisms and as such could be particularly good for understanding how eukaryote microbiomes originate and are maintained. One such amoeba, Dictyostelium discoideum, has both permanent and temporary associations with bacteria. Here we focus on culturable bacterial associates in order to interrogate their relationship with D. discoideum. To do this, we isolated over 250 D. discoideum fruiting body samples from soil and deer feces at Mountain Lake Biological Station. In one-third of the wild D. discoideum we tested, one to six bacterial species were found per fruiting body sorus (spore mass) for a total of 174 bacterial isolates. The remaining two-thirds of D. discoideum fruiting body samples did not contain culturable bacteria, as is thought to be the norm. A majority (71.4%) of the unique bacterial haplotypes are in Proteobacteria. The rest are in either Actinobacteria, Bacteriodetes, or Firmicutes. The highest bacterial diversity was found in D. discoideum fruiting bodies originating from deer feces (27 OTUs), greater than either of those originating in shallow (11 OTUs) or in deep soil (4 OTUs). Rarefaction curves and the Chao1 estimator for species richness indicated the diversity in any substrate was not fully sampled, but for soil it came close. A majority of the D. discoideum-associated bacteria were edible by D. discoideum and supported its growth (75.2% for feces and 81.8% for soil habitats). However, we found several bacteria genera were able to evade phagocytosis and persist in D. discoideum cells through one or more social cycles. This study focuses not on the entire D. discoideum microbiome, but on the culturable subset of bacteria that have important eukaryote interactions as prey, symbionts, or pathogens. These eukaryote and bacteria interactions may provide fertile ground for investigations of bacteria using amoebas to gain an initial foothold in eukaryotes and of the origins of symbiosis and simple microbiomes.
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Affiliation(s)
- Debra A Brock
- Queller/Strassmann Laboratory, Washington University in St. Louis, Department of Biology, St. Louis, MO, United States
| | - Tamara S Haselkorn
- Queller/Strassmann Laboratory, Washington University in St. Louis, Department of Biology, St. Louis, MO, United States
| | - Justine R Garcia
- Queller/Strassmann Laboratory, Washington University in St. Louis, Department of Biology, St. Louis, MO, United States
| | - Usman Bashir
- Queller/Strassmann Laboratory, Washington University in St. Louis, Department of Biology, St. Louis, MO, United States
| | - Tracy E Douglas
- Queller/Strassmann Laboratory, Washington University in St. Louis, Department of Biology, St. Louis, MO, United States
| | - Jesse Galloway
- Mountain Lake Biological Laboratory, University of Virginia, Mountain Lake, VA, United States
| | - Fisher Brodie
- Mountain Lake Biological Laboratory, University of Virginia, Mountain Lake, VA, United States
| | - David C Queller
- Queller/Strassmann Laboratory, Washington University in St. Louis, Department of Biology, St. Louis, MO, United States
| | - Joan E Strassmann
- Queller/Strassmann Laboratory, Washington University in St. Louis, Department of Biology, St. Louis, MO, United States
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